ACTA PHYTOGEOGRAPHICA SUECICA 78

Guest editors: Inger Wallentinus & Pauli Snoeijs

Phycological studies of Nordic coastal waters

- A festschrift dedicated to Prof. Mats W rern on his 80th birthday -

Editor-in-Chief· Erik Sj ogren

OPULUS Press AB UPPSALA 1992 Thi volume of Acta Phytogeographica Suecia 'Phycological studies of Nordic coa tal waters' is dedicated to profe or Mat Wremon his 80th birthday, May 28, 1992. The contributors are invited phycologist who are worldng with marine and brackish-water plant in the Nordic countries. The volume ha been financially upported by grant from: Nordiska Kulturfonden, Nordiskt Kollegium fo r Marinbiologi, Goteborgs Marina Forskningscentrum, Stockholms Marina Forskningscentrum, Umea Marina Forskningscentrum, lnstitutionen fo r Systemeko/ogi vid Stockholms Universitet, Waiter och Andree de Nottbecks Stiftelse and Svenska Viixtgeografiska Sallskapet. Grants for printing the colour plates have been received directly by the authors. We are also much indebted for all assistance from the Department of Marine Botany, University of Goteborg.

ISBN 91-72 10-078-8 (paperback) ISBN 91-72 1 0-478-3 (cloth) ISSN 0084-59 14

Editor: Erik Sjogren Guest editors: Inger Wallentinus & Pauli Snoeijs

Editorial Board:

A.W.H. Damman, Storr , CT F.J .A. DanieJs, MUnster L. Ericson, Umea 0. Gj rerevoll, Trondheim D. Glenn-Lewin, Ames, lA 0. Hamann, Copenhagen H. Sjor , Uppsala H. Trass, Tartu

Technical editor: Marijke van der Maarel-Ver luy

©Respective author 1992

Drawing of Ceramium tenuicorne on the cover by Pauli Snoeijs

Edidit: Svenska Vaxtgeografiska Sallskapet Box 559, S-75 1 22 Uppsala

DTP: Opulu Press AB, Upp ala Phototypesetting: Fotosattarna i Uppsala AB Printed in Sweden 1992 by TK i U ppsala AB, U pp ala

Acta Phytogeogr. Suec. 78 Contents

Preface A tribute to Mats Wc.ern - the nestor of modern Swedish phycology. By lnger Wa llentinus, Marianne Pedersen & Pauli Snoeijs. 5

Ecology and taxonomy of Enteromorpha species in the vicinity of the Forsmark nuclear power plant (Bothnian Sea). By Pauli Snoeijs. 11

Effects of nutrient enrichment on planktic blue-green algae in the Baltic Sea. By Kerstin Wa llstrom, Sif Johansson & UlfLarsson. 25

Studie on the Fucus vesiculosus community in the Baltic Sea. By Hans Kautsky, Lena Kautsky, Nils Kautsky, Ulrik Kautsky & Cecilia Lindblad. 33

Contribution to the seaweed flora of Sweden: New or otherwise interesting records from the west coast. By }an Karlsson, Mats Kuylenstierna & Per Aberg. 49

Colonization and succession of macroalgae on a breakwater in Laholm Bay, a eutrophicated brackish water area (SW Sweden). By To re Wennberg. 65

f Chorda tomentosa Lyngbye in Finnish coastal water . By Guy Hiillors & Kaarina Heikkonen. 79

Primary production of macroalgae in relation to the spectral range and sublittoral light conditions in the Tvarminne archipelago, northern Baltic Sea. By Elina Leskinen, Anita Miikinen, Wilhelm Fortelius, Magnus Lindstrom & Heikki Salemaa. 85

Effects of ferry traffic on the metal content of Fucus vesiculosus in the Aland archipelago, northern Baltic Sea. By Olof Ronnberg, Toro ifO stman & Kaj Adj ers. 95

Floristic aspects of the coastal inlet Inre Verkviken, northern Aland. By Hans Mathiesen & Lisbeth Mathiesen. 101

Marine algae south of the island Vejrp, the Sam p area, Denmark. By Ruth Nielsen & Karsten DahL 111

Changes in fucoid distributions and abundances in the inner Oslofjord, Norway: 1974-80 versus 1988-90. By To r L. Bokn, Steven N. Murray, Frithjof E. Moy & Jan B. Magnusson. 117

Field and culture observations on Uronema curvatum Printz (Chlorophyta). By Jan Rueness. 125

The gradient of the benthic algal vegetation along the eastern Icelandic coast. By lvka M. Munda. 131

Acta Phytogeogr. Suec. 78

A tribute to Mats Wcern

Mats Wcern.

A tribute to Mats W cern - the nestor of modern Swedish phycology

Inger Wa llentinus1, Marianne Pedersen2 & Pauli Snoeijs3

1 Department of Marine Botany, University of Goteborg, Carl Skottsbergs gata 22, S-413 19 Goteborg, Sweden; 2Department of Physiological Botany, Uppsala University, Box 540, S-751 21 Uppsala, Sweden; 3DepartmentofEcological Botany, Uppsala University, Box 559, S-751 22 Uppsala, Sweden.

For centuries, Swedish scientists have studied the taxonomy professors G. Einar Du Rietz and Rutger Sernander, was and biology of algae. C. von Linne included already in the awarded the highest degree at the University ofUppsala and 18th century algae in his studies. He was followed by made him famous all over the world. It became the classic famous algologists such as C. A. Agardh, his son J. G. work for quotations on the Baltic algae and their ecology. Agardh, J. E. Areschoug, F. R. Kj ellman, N. Svedelius, C. Mats was not only inspired by his predecessors; his Skottsberg and H. Kylin. When Mats Wrern started his greatest inspiration has always been the sea. Together with studies on algae, and also on brackish water phanerogams his family and friends he made many summer excursions to in the late 1920s, he was certainly inspired by the works of the archipelago of Oregrund, an area which is through his those famous phycologists. Some of them were his tutors, as thesis now well known to marine scientists all over the he has pointed out in the preface to his doctoral thesis world. In the preface to the thesis he described how his (Wrern 1952). This thesis, prepared at the Department of mother performed the difficult task of navigating in these Ecological Botany (Yaxtbiologiska institutionen) under tricky waters, with many rocks hidden just below the water

Acta Phytogeogr. Suec. 78 6 I. Wa llentinus et al.

surface. Stina Wrern,his wife, played the important role of camped on the islands during the diving periods; the list of secretary and dive watcher when Mats examined the flora provisions included hard bread, butter, salt, bacon, eggs, several fathoms under the surface. In 193 8 Mats W rem herring, cocoa, milkpowder, beer and Swedish canned tarted to dive in order to study the algae down on the sea­ 'blodpudding' (blackpudding). Unfortunately, because of bed. Scientific diving was a rather new method to study the World War 11 Mats was not able to fulfil his aim to study the marine environment. Earlier, Gislen (1929-30) had used a algal vegetation across the Baltic Sea, to determine the hired diver and made ome dives himself, in order to study influence of the gradient in alinity on pecies distribution the hard-bottom communities of the Gullmar Fj ord at the and to compare the ecology of the algae on the easternand Swedish west coast. Previously dredging wa used to collect western side of the Baltic Sea. algae from the sublittoral. This method had the drawback To be able to photograph the algae, Mats designed a that algae from different levels were mixed, which made it special housing for his Rolliflex camera, which was built by impossible to determine the depth interval along which John Ambertsson at the In titute of Chemistry, University different algal species occur. Neither could any quantitative of Upp ala. This enabled him to adjust the distance and measures be obtained. wind the film after the camera hou ing was screwed down Mats wanted to know the exact position of these upper with 16 winged nuts. The time and aperture had to be et in and lower limits of species distribution and how they vary advance. A Sixtus light meter was kept in a preserving-jar. with salinity. He soon came to the conclusion that scientific Mats reported aperture and time to the boat, where the precision could only be reached by using a diving suit, and camera was prepared and lowered down to him, and then he by documertting the vegetation through photography and waited until the light meter gave the same values as before. verbal comments over a telephone. In those days one had to When the diver found an interesting and suitable place he use a heavy suit; the aqualung of Costeau and Gagnan was ordered "Weight down" and determined the depth. He then not invented until 1943. Dr. Hans Hass, the famous diver made a general survey of the ea-bed and all vegetation in and photographer, took his first under-water photos in Dal­ sight, usually to a distance of 2-8 m, and estimated the matia in the same year as Mats did in Sweden, 1938. degree of cover of the different algal species on a 1-5 scale. The expenses during the first year of the project were A frame was placed on the rock and Mats reported the cover covered by Mats' father. Certainly, the University was values by telephone to the record-keeper in the boat. Then, interested in the work, but Mats preferred not to ask for a all algae within the frame were scraped off from the surface grant, as he did not want to be compelled to continue diving and collected in a bag, which was sent up and numbered for if he found it too hard. His mother was also intere ted in the further analyses in the laboratory. project; she insisted on making one of the first dives, just to Apparently, the record-keepers have bowdlerized his re­ see that it was not too dangerous for her son. ports from the sea bottom, with the exception of Stina The diving suit was a German double suit, which Mats Wrern, who wrote down everything Mats said. The diving preferred because it allowed him to crawl safely on his reports provide evidence of his devotion and enthusiasm for knees while scraping off the algal vegetation. The alterna­ this task. One of us (M. P.) had the privilege to read the tive was the English suit, which had lead weights suspended diving reports and compare them with the precise cientific from the chest. If the diver would lose balance using this text presented later in his thesis. At the occasion of Mats' suit, he would come up feet first. The suit had rubber gloves, jubilee we will present ome fragments of the diving min­ which were sealed with dry bits of string, which shrank utes (in translation). when becoming wet. Lead-covered boots and a lifeline were used as well. Before the copper helmet was bolted into Kosten, July 4, 1944. Minutes: "Here it's deep and place, the pump connected to the suit was started. Two men rather muddy. The bottom is yellow, poor visibility. were needed to operate the pump during the long dives, I don't like walking here. The bottom is loose and which usually lasted for four to five hours. Besides the two covered with boulder and stones. Nothing remains men for the pump, Mats needed four assistants: one diver's still down here, neither algae nor I, nor the camera. assistant, one person to write down the diving records, while (Later) Observation place depth 2 m. Rocks. The two others, following in a rowing boat, supplied him with rock is like a bald head and just where the baldness is, camera, buckets, etc. Thus, all in all, six assistants were there is no bottom layer and no red or brown algae. I' 11 needed. Today it would be very difficult to carry out such a take a bloody good picture." costly project, but fortunately, diving has become less cum­ Kosten. Thesis (p. 275, plate 24) : "The diving started bersome. about 10 m beyond the shore-line of the skerry in a The dives were often interrupted by military inspections. hilly sea-landscape, in a group of rock-outcrops or Mats had permission from the Naval Commander-in-Chief shallows .... The slopes of these rock-outcrops are to dive inside a certain area, which was marked with buoys. covered with a stubbed growth of Cladophora

During World War 11, when there was a shortage of petrol, glomerata (cover degree 5). The edges of certain they could not use the motor vessel but had to sail to the rock-outcrops are destitute of any growth of tuft islets where the dives were performed. The whole crew algae, obviously shaven by the ice, see pl. 24, now

Acta Phytogeogr. Suec. 78 A tribute to Mats Wcern 7

bearing a thin cover of Diatoms (with Rivularia Through his systematical approach and cruttmzmg biasolettiana)." taxonomical work Mats laid the basis for modem marine algal tudies in Sweden. Already in the beginning of his Kosten. Minutes: "I can see a turbot looking at me! studies, Mats had learnt to emphasize the significance ofthe Once one comes down from the smooth hill there are common algae and the role they play along our coasts. This boulders here. Send the camera down. Hardly any wa later manifested in Mats' huge collections of pres ed Enteromo rp ha here - well I' 11be damned ifthere isn't and preserved algae, not only as taxonomical records, but one over there". also with the wider perspective of documenting the status of Kosten. Th esis (p. 276): "Enteromorpha intestinalis the vegetation at different localities as protocols in an is apparently very scarce, noticed only once at about 'ecological herbarium'. 2.5 m zenith." Mats has always combined taxonomy, ecology and chorology in his algal tudie . Many papers provide evi­ Vassaro Viten. Minutes: "I'm walking downwards. dence of hi taxonomic competence (Wrem 1936, 1940, This would make a good picture. Send down the 1945, 1949, 1952, 1958, 1960a, 1960b, 1961, 1992, Skytte camera. Time 1125 and aperture 6.3. Vegetation rich. Chri tian en et al. 1976, Willen & Wrem 1987). For in­ Send down bucket and bags. I am now craping off stance, he has unravelled the Sphacelaria complex on the the algae inside the iron frame. Difficult to take a Swedish east coast, which previously was considered to photo. The stand is swaying. The balance is bad. consist of two species; Mats found that in fact six distinct Something is wrong. Camera up. Now I can see that species were involved (Wrem 1945). Mats also described the back screw is not tightened in the camera housing. some algal taxa new to science, e.g. the genus Porterinema I'll come up at 12.37. (Down again at 13. 15.) I'll take (Wrem 1952), and the species Lithoderma rosenvingii, L. a good picture. Distance 2 m. The vegetation gets subextensum (Wrern 1949), Entocladia cyclostoma, thinner as I walk downwards. Bloody beautiful pic­ Nematochrysishi eroglyphica (Wrem19 52), and Ceramium ture if there will be anything on the film. Blast!! The gobii (Wrem 1992); and he made new nomenclatural com­ film is finished. Up with the damned camera." - Stina binations, e.g. Wrem (1952): Ceramium tenuicorne (Ktitz.) wrote the following note: "Damned and bloody are Wremand Porterinema fluviatile (Porter) Wrem. He also the most frequent words on the telephone and need found about 60 algal species new for Sweden. not be noted in the minutes". There are also some algal taxa named in honour of Mats Vassaro Viten. Th esis (plate 22): "Hydro- ublittoral Wrem.The cave-dwelling, minute brown alga earlier known rock-pool with boulders; ...Backgr ound 2.2 m from as Leptonema lucifugum Kuckuck, recorded for Sweden for camera. To the right on steep rock lope, border the first time by Wrem, wa transferred to the new genu between hydro- and sublittoral .... Hydrolittoral bare Waerniella by Kylin (1947). Recently a new epiphytic to naked eye. Sublittoral with a silky, short and thin brackish-water diatom Ta bularia waernii was described growth of Cladophora glomerata, Ceramium tenui­ from the Baltic Sea (Snoeij & Kuylenstiema 199 1). corne, (with Rivularia biasolettiana), Stictyosiphon Despite Mats' great achievements as a taxonomist, he is tortilis .... " most outstanding as an ecologist with his thorough knowl­ edge of the benthic vegetation, particularly along the Swed­ Stora Korssten. Minutes: "Oh hell, omething fine ish coasts (e.g. W rem 1940, 1946, 1948, 1950, 1952, 1958, here! No it's not what I thought - it' Ruppia, but 1959, 1964, 1965a, Skytte Chri tian en et al. 1976). Many possibly also Zostera marina, in that case a sensa­ of the species he recognized in the bregrund archipelago are tional finding of this plant. Camera down! The light characteristic of brackish water, or fresh-water species not values are low. The boat casts a shadow. Difficult to recognized earlier in haline environments, but later found to walk, I' 11 inflate my suit and swim. You bloody fool, be common also at other coasts around the world. In several there is a fly in the camera housing. Pull up the of his papers, including the review 'A vista on the marine camera!" Then Stina made the following remarks in vegetation' (Wrem 1 965a), Mats convincingly demonstrated the minutes: "Phase 1: Diver angry. Crew muddle­ the impact of the salinity gradient on the benthic vegetation, headed. Phase 2: Diver angry. Crew angry. Phase 3: along a gradient from the marine shores into the brackish Silence." Baltic Sea, the basins of which he compared with "rock "I've spoiled the visibility completely here by tram­ pools of extraordinary size" (Wrem 1959). pling around. I can't see anything, I'll move to He also studied the algal vegetation in other countries another place. It's so hellishly slippery here." such as the Baltic coasts of Finland and Germany in the Stora Korssten. Th esis (plate 18) "Rock-outcrop with 1930s, the coasts of Denmark, the Netherlands and Brittany, shrubs of high, tough warped, Fucus vesiculas us .... France in the 1940s (Wrem 1952), and the Norwegian Algae powdered white with sediments; a walk through shores in the 1950s (Wrem 1965 a). In 1962 he organized a this growth moves up the sediments and disturbs the cruise with RIV Sunbeam to the Mediterranean Sea, in visibility for a long time." which several of his students participated.

Acta Phytogeogr. Suec. 78 8 /. Wallentinus et al.

Mats has also been interested in fresh-water algae, especi­ team which went along the Swedish Kattegat coast with ally during the early years of his studies (Wrem 1938, RJV Sunbeam. The life on board, lasting for weeks and not 1939a, 1939b). He has made very valuable contributions to always very comfortable, did not restrain Mats who still is a the knowledge of the ecology of microalgae, submersed very active researcher. During the first cruise in the autumn phanerogams, and mosses as well. Mats' early interest in of 1988 the goal was to study the effects of the novel toxic brackish-water phanerogams led to a friendship with the phytoplankton bloom, in the spring of 1988, of Chryso­ late professor Hans Luther (University of Helsinki, Fin­ chromulina polylepis (Marston & Parke) which had devas­ land), another great botanist, who studied the Baltic flora, tated the benthos in large areas, particularly above the and worked in Uppsala at the time Mats prepared his disser­ halocline. The aim of the two cruises in 1989 was to follow tation. the recovery after the bloom. The recovery for some algae Another very important role Mats played was that of a was faster than expected. During these cruises, also changes tutor and supervisor. His lectures at the department, the at Mats' old collecting sites on the Swedish west coast and participation as a teacher in several field courses and excur­ those of Rosenvinge in the Kattegat were studied, the latter sions, both in Sweden and abroad, and his participation in in cooperation with Danish scientists. At the same time symposia and congresses have contributed substantially to Mats both made several novel studies on the crus to se brown the growth of phycology as a discipline and to the increase algae, and enthusiastically directed the divers where to in the number of phycologists. Many of us will always collect and to take photographs and video tapes of the remember the long talks and his enthusiasm when some vegetation. interesting algae had been found - or not found-, and the late Mats' career as a phycologist and marine scientist extends hours spent on discussing algae, often without time for over more than 60 years and his enthusiasm and intellectual having supper, sometimes until sunrise. Many are the days capacity have greatly inspired many students and colleagues when the light was switched off late at the department or on over the years. Mats is still active and continues to make a board RJV Sunbeam, when Mats was studying, drawing and deep impression on the young students of today, who have preserving algae. And to correctly collect, press and draw found a true nestor of phycology in Mats Wrern. algae has always been something he persuaded us to do - and With this volume 'Phycological studies of Nordic coastal we hope we have learnt. waters' we all, in Sweden, in the Nordic countries and all Mats has always been very much interested in marine over the world, would like to thank Mats for everything we environmental issues, and he became worried about the have learnt from him in a most inspiring way. Many more ongoing changes. During several cruises with RJV Sun­ scientists, also from outside the Nordic countries and repre­ beam along the Swedish coasts during the 1960s, measure­ senting other scientific fields, did not have the opportunity ments of the water quality were carried out simultaneously to contribute. The papers devoted to Mats in this volume with algal studies (e.g. Anon. 1963, 1964, 1968, Wrern have been written by scientists of the N ordic countries, who 1965b, 1966). In the 1970s Mats was the leader of a large have been inspired by his work. We all wish to say: "Happy project carried out in the Stockholm archipelago (Wrern birthday to you! Thank you for all you have contributed to 1972, 1973, Norin & Wrem19 73, Wrem& Hiibinette 1973, science and for what you have meant for us. We look Wrem& Pekkari 1973). In this project, initiated by the city forward to learn more from you!" of Waxholm, the influences of the discharges both from the large lake Malaren and the long history of discharges from sewage treatment in Stockholm on the water quality and algae in the archipelago were studied. Measurements were References also carried out in the Aland Sea (Wrern & Ek 1973). Mats' earlier studies are extremely valuable as a reference Anon. 1963. Marinbotanisk forskningsfard. - Sven. Bot. Tidskr. 57: 500. for recording changes in the algal vegetation, both in the Anon. l 964. UndersokningsfartygetSunbearn. -Sven. Bot. Tidskr. Baltic Sea and on the Swedish west coast, changes which 58: 533. have been documented in several recent studies. In 1984 Anon. l968. UndersokningsfartygetSunbearn. -Sven.Bot. Tidskr. Mats was actively involved in revisiting, after 40 years, his 62: 440. old diving sites in the bregrund archipelago: large changes Collen, J. & Pedersen, M. 1990. Vasterhav i forvandling. En studie in the distribution of Fucus vesiculosus and the deeper av alger. - In: Bohuslan Arsbok 1990. Bohuslans hem­ living algal communities were found (Kautsky et al. 1986, byggdsfOrbund och Bohuslans museum, Bohuslans museum, Kautsky et al. 1992). Others have revisited his former Uddevala. pp. 81-86. diving sites on the Swedish west coast and found changes in Gislen, T. 1929-30. Epibiosis of the Gullmar Fjord 1-11. - Kristinebergs Zoologiska Station 1877- 1 927. Nr 3-4. KVA, the depth distribution and composition of species (Pedersen Stockholm, 123 + 380 pp. 6 Plates. 1989, Collen & Pedersen 1990, Pedersen et al. 1990, Kautsky, H., Kautsky, L., Kautsky, N., Kautsky, U. & Lindblad, C. Soderlund & Bjork 1990, Soderlund & Pedersen submitted, 1992. Aspects on the Fucus vesiculosus community in the H. Kautsky pers. comm.). Baltic Sea. -Acta Phytogeogr. Suec. 78: 33-48. In 1988 and 1989 Mats was an enthusiastic member of the Kautsky, N., Kautsky, H., Kautsky, U. & Wrern, M. 1986. De-

Acta Phytogeogr. Suec. 78 A tribute to Mats Wcern 9

crea ed depth penetration of Fucus vesiculosus L. since the marines. Colloque Internationaux du Centre National de la 1 940's indicates eutrophication of the Baltic Sea. - Mar. Ecol. Recherche Scientifique 81, Dinard 20-28 eptembre 1957. Prog. Ser. 28: 1-8. CNRS, Paris. pp. 45-55. Kylin, H. 1947. Die Phaeophyceen der Schwedischen Westkiiste. Wrern, M. 1960a. A preliminary check-li t of Swedi h marine - Lunds Univ. A.r skr. N.F. Avd. 2, 40: 1-104. algae. Rhodophyceae and Phaeophyceae. - Dept. of Ecologi­ Norin, L. & Wrern, M. 1973. The zone of algal low standing crop cal Botany, Uppsala Univ. 12 pp. (Mimeographed.) near Stockholm. Nutrients and their influence on the algae in Wrern, M. 1960b. Bentiska chrysophyceer i havet. - Sven. Bot. the Stockholm Archipelago during 1970. No. 5. - Oikos Tidskr. 55: 254. Suppl. 15: 179- 1 84. W rern, M. 1961. Tillagg till Sveriges rodalgsflora (preliminart Pedersen, M. 1 989. Dramatic changes of rocky-shore algal vegeta­ meddelande). 1. Om Bertholdia neapolitana, Antithamnion tion on the Swedish west coast 1988. - Applied Phycologica1 tenuissimum och Polysiphonia nigra i Bohuslan. 2. Om Forum, Newsletter for Algal Biotechnology 6 (1): 2-3. Dumontia-kru tan och andra rodalgskrustor i Bohuslan. - Pedersen, M., Bjork, M., Larsson, C. & Soderlund, S. 1990. Ett Sven. Bot. Tid kr. 55: 234-236. marint ekosy terni obalan - dramatiska fOrandringar av hard­ Wrern, M. 1964. En algbevuxen torvbotten i Laholmsbukten. bottnarnas vaxt amhallen. - Flora Fauna 85: 202-2 1 1. [Algal growth on a peat-bottom in Laholm Bay, West Coast of Skytte Christiansen, M., von Krusenstjerna, E. & Wrern,M. 1976. Sweden.] - Sven. Bot. Tid kr. 58: 309-3 14. (With English Yar flora i farg. Kryptogamer. - Almqvist & Wiksell, Stock­ summary.) holm. 325 pp. Wrern, M. 1965a. A vista on the marine vegetation. - Acta Snoeij , P. & Kuylenstierna, M. 1991. Two new diatom species in Phytogeogr. Suec. 50: 15-27. the genus Ta bularia from the Swedish coast. - Diatom Res. Wrern,M. 1965b. Undersokningsfartyget Sunbeam.- Sven. Bot. 6: 35 1-365. Tidskr. 59: 514-5 15. Soderlund, S. & Bjork, M. 1990. Radda vara undervatten kogar. Wrern, M. 1966. Undersokningsfartyget Sunbeam.- Sven. Bot. - Sveriges Natur 1990 (6): 16-19. Tidskr. 60: 510-5 12. Soderlund, S. & Peder en, M. ( ubmitted). Hotade kogar i havet Wrern, M. 1972. Outflow from Lake Malaren and distribution in - en bok om algernas miljo. time and space of mineral nutrients in the Stockholm archi­ Wrern,M. 1936. Leptonema lucifugum, en for Sverige ny brunalg pelago during 1970. - Ambio Special Report 1: 59-60. i hygrohalina grottor. [Leptonema lucifugum, a brown alga in Wrern, M. 1973. Nutrients and their influence on the algae in the hygrohaline caves, new for Sweden.]- Sven. Bot. Tidskr. 30: Stockholm Archipelago during 1970. Introduction. - Oikos 329-342. (With English summary.) Suppl. 15: 153-154. Wrern,M. 1938. Om Cladophora aegagropila, Nostoc pruniforme Wrern,M. 1992. Ceramium gobii n. sp., a red brackish water alga och andra alger i Lilla Ullevifjarden, Malaren. [On Cladophora in the Baltic Sea. - Nord. J. Bot. 12. aegagropila, Nostoc pruniormef and other algae in Lilla Wrern, M. & Ek, K. 1973. Residual nitrogen in the Aland Sea. ­ Ullevifjarden, Lake Malaren.] - Bot. Not. 1938: 129- 142. In: Second Swedish-Soviet sympo ium on the control of the (With Engli h ummary and legends.) Baltic Sea pollution, Riga, September 1973. 7 pp. + 6 Figs. Wrern, M. 1939a. Epiliti che Algenvegetation (Takern). - Acta Wrern, M. & Hiibinette, L. 1 973. Phosphate, nitrate and ammonium Phytogeogr. Suec. 12: 43-50. in the archipelago during 1 970. Nutrient and their influence on Wrern, M. 1939b. Die Exkursion an dem Malaren mit Aufenthalt the algae in the Stockholm Archipelago during 1970. No. 2.­ am Lilla Ullevifjarden.-IX. Intern. Lirnnol. Kongr. Schweden. Oiko Suppl. 15: 164- 173. Allgem. Fiihrer. Stockholm, pp. 51-54. Wrern,M. & Pekkari, S. 1973. Outflow tudies. Nutrients and their Wrern,M. 1940. Cladophora pygmaea und Leptonema lucifugum influence on the algae in the Stockholm Archipelago during an der schwedischen Westkiiste. - Acta Phytogeogr. Suec. 13: 1970. No. 1.- Oikos Suppl. 15: 155-163. 1-6. 1 Plate. Willen, T. & Wrern, M. 1987. Alger med svenska namn. [Algae Wrern, M. 1945. Remarks on some Swedish Sphacelariaceae. ­ with Swedish names.] - Sven. Bot. Tidskr. 81: 281 -288. Sven. Bot. Tidskr. 39: 396-4 18. 2 Plates. Wrern, M. 1946. Algvegetationen vid Gotlands kuster. - In: * Doctoral dissertation Uppsala University Pettersson, B. & Curry-Lindahl, K. (eds.) Natur pa Gotland. Bokforlaget Svensk Natur, Stockholm, pp. 190- 194. Wrern, M. 1948. Algvegetationen vid Upplands klippstrander.­ In: Horstadius, S. & Curry-Lindahl, K. (eds.) Natur i Uppland. Bokforlaget Svensk Natur, Stockholm. pp. 252-260. Wrern, M. 1949. Remarks on Swedish Lithoderma. - Sven. Bot. Tidskr. 43: 633-670. 3 Plates. W rem, M. 1950. Algological excursions to the middle part of the Swedish east coast. - 7th Intern. Bot. Congr., Stockholm 1950. Excursion guides B 3 and C Ill a. Uppsala. 38 pp. Wrern,M. 1952. Rocky-shore algae in the Oregrund Archipelago. -Acta Phytogeogr. Suec. 30: I-XVI + 1-298. 32 Plates*. Wrern, M. 1958. Phycological investigations of the Swedish west coast. I. Introduction and study of the Gaso shell-bottom. - Sven. Bot. Tidskr. 52: 319-342. 4 Plates. Wrern, M. 1959. Repartition des algues «franr;aises»dans les eaux suedoises, marines et saumatres. - In: Ecologie des algues

Acta Phytogeogr. Suec. 78

Ecology and taxonomy of Enteromorpha species in the vicinity of the Forsmark nuclear power plant (Bothnian Sea)

Pauli Snoeijs

Abstract Snoeij , P. 1 992. Ecology and taxonomy of Enteromorpha species in the vicinity of the Forsmark nuclear power plant (Bothnian Sea). -Acta Phytogeog r. Suec. 78, Uppsala. ISBN 91-72 1 0-078- 8.

The ecology and taxonomy of three Enteromorpha pecie were studied in the upper littoral around the Forsmark nuclear power plant during one growing ea on (March-November 1991). Monthly field samples were taken from ten sites within reach of the cooling water di charge, and from ten sites that were not or only marginally affected by thermal discharge. The ampling site also varied in water movement conditions. In January 1992 overwintering algae were studied at the sites that were not ice-covered.

Cladophora glomerata, Ceramium tenuicorne, Enteromorpha ahlneriana and E. intestinalis are the dominant belt-forming macroalgae throughout the year in the area. The red alga C. tenuicorne is negatively affected by cooling water discharge, whereas fast-growing green fi lamentou algae are promoted. E. ahlneriana was favoured most by heating, which may be explained by its wide ecological amplitude and excellent competitive abilities, notably its overwintering capacity, wide variety in thallus morphology, and low amounts of epiphytes. The plants of E. intestinalis become longer in the discharge area, but its cover was only affected positively in winter and spring, and in water with artificial flow conditions throughout the year. The summer specie E. clathrata also howed a positive response to heating.

Keywords: Algae; Baltic Sea; Brackish water; Cooling water.

P. Snoeijs, Department of Ecological Botany, Uppsala University, Box 559, S-751 22 Uppsala, Sweden.

Introduction reported to increase in abundance near cooling water dis­ charges to the Baltic Sea, whereas E. intestinalis was not The species belonging to the genus Enteromorpha affected (Keskitalo & llus 1987, Snoeijs & Prentice 1989). ( Chlorophyta) are annual macroalgae with tube-like branched The aims of this study are: 1. To study the taxonomy of or unbranched thalli. The genus is of marine origin, but the Enteromorpha species at Forsmark in greater detail, by some species penetrate far into the brackish Baltic Sea. studying larger populations from more sampling sites than Enteromorpha spp. are especially abundant in the upper in previous studies (Snoeijs 1987). 2. To study occurrence littoral, where they can be belt-forming in pure stands or and abundance of the different Enteromorpha species in together with Cladophora glomerata and/or Ceramium relation to (natural and anomalous) environmental factors tenuicorne. Enteromorpha spp. are capable of fast growth throughout one seasonal cycle. 3. To study plant size (length under favourable conditions, react quickly to environmental and width), appearance (branching), cell size, and occur­ changes, and they are known as positive indicators of rence of swarmers (propagation) throughout one seasonal eutrophication (e.g. Hayren 1921, Wrem 1952, Peussa & cycle. 4. To discuss the competitive abilities of Entero­ Ravanko 1975, Wallentinus 1979, Kautsky 1982, Viitasalo morpha species in relation to the accompanying algal veg­ 1984, 1990, Hallfors et al. 1987). E. ahlneriana has been etation.

Acta Phytogeogr. Suec. 78 12 P. Snoeijs

' Study area ' I BOTHNIAN ' I__ , SEA Forsmark is situated on the east coast of Sweden at the NORWAY\ southern end of the Gulf of Bothnia (Fig. 1), ea. 130 km I I north of Stockholm (60° 25' 80" N, 18° 11' 14" E). Salinity I

in the area is ea. 5 and the tide is negligible ( < 5 cm), ,,' %o, I I while weather induced changes in water level can reach I I about 1 m (low in spring and high in autumn). The cooling I .. I water from the Forsmark nuclear power plant is led through :�/ an artificial enclosure, the Forsmark Biotest Basin (Fig. 2), ::: =:. before it is returned to the Baltic Sea. The basin was �:·::�6 constructed especially for environmental impact studies (Grimas 1979). It has an area of ea. 1 krn2 and provides a SWEDEN range of environments, from stagnant water to fast flow, and temperatures increased by various amounts. Inside the basin the water level is regulated, but the yearly water-level

BALTIC PROPER

Table 1. The sampling sites.

Mean Flow Ice cover Site Site temperature fa ctor in category number anomaly (min-max) winter (0C) Fig. 1. Location map.

SITES WITH ARTIFICIAL UNIDIRECTIONAL WATER FLOW

Reference sites 0.0 4. yes 2 0.0 4 no* fluctuation is similar to that outside the basin (ea. 1 m). An

Heated sites 3 7.0 2-6 no ice cover is never formed inside the Biotest Basin. The Discontinuous flow 4 7.8 3-6 no surroundings of the basin provide a complementary set of environments, with and without ice cover and with varying Heated sites 5 7.6 4-5 no Continuous flow 6 8.4 4-5 no degrees of heating (e.g. by leakage from the basin) and varying exposure to waves. The intake channel has un­ MORE-OR-LESS EXPOSED SITES heated, slowly flowing water. There is also a stand-by Reference sites 7 0.0 3 yes outlet, where part of the cooling water can be released 8 0.0 2 yes directly in the archipelago north of the basin. For further

Slightly heated sites 9 1.1 3 yes area description see Snoeijs & Prentice (1989). 10 1.7 2 yes

Heated sites 11 3. 1 3 yes 12 5 .3 3 no 13 5.4 2 no Methods

SITES WITH MORE-OR-LESS STAGNANT WATER Twenty sampling sites were selected to obtain as much 4 Reference sites 1 0.0 t yes variation in degree of heating and water movement as 15 0.0 0 yes possible (Fig. 2, Table 1). All sampling sites were visited 16 0.0 0 yes between the 19th and the 26th of each month from March Slightly heated site 17 0.8 yes 199 1 (just afterice- break) until November 199 1 (before ice­

Heated sites 1 8 3.0 1 no formation), nine times altogether. Winter samples were 19 4.2 0 no taken once, on 20 January 1992, from the sites that were not 20 4.5 0 no ice-covered. The algae were sampled in the upper-littoral zone (10-60 cm depth). Flow factor: 0: stagnant; 1: quiescent; 2: little exposed; 3: much exposed; 4: For each site/date water temperature and salinity were slowly flowing; 5: flowing; 6: rapidly flowing. The flow factors at Sites 3-6 vary between sampling dates depending on measured with a Yellow Springs Instrument Model 33. The the path of the cooling water and periods of overhaul of the power plant. seasonal trend of insolation in the area is known from

* = no ice cover is formed because the cooling water is continuously taken previous years (Snoeijs 1985). Water samples (from site 2 from under the ice before the bridge over the intake channel (Fig. 2); the throughout the sampling period, and from all sites in No­ concrete bridge reaches down to about 3 m under the water surface. vember) were frozen, and nutrient concentrations (N02-N,

Acta Phytogeogr. Suec. 78 Ecology and taxonomy of Enteromorpha species 13

Fig. 2. The Forsmark nuclear power plant and the Biote t Ba in, howing the 20 ampling ites.

N03-N, P04-P and silicate) were analysed. Seven sites from these micrographs (six squares, two from each micro­ outside the basin, with different degrees of water move­ graph). A herbarium was established of Enteromorpha, ment, served as reference sites for water temperature. The from which later maximum plant length and width (width = degree of heating (= 'temperature anomaly') for each site/ 0.5 x tube-outline of the main stem) were measured. This date was calculated as the difference in water temperature herbarium is kept at the Department of Ecological Botany in between the sampling site and the mean of the reference Uppsala. sites with the same conditions of water movement (= 'back­ Canonical correspondence analysis (CCA), implemented ground water temperature'). with the program CANOCO (ter Braak 1986), was applied For each site/date, the cover of each macroalgal species to summarize variation in macroalgal community composi­ (and bluegreens if occurring in colonies visible to the naked tion related to site, month and environmental variables. eye) was estimated in the field according to a cover scale (Table 2). Samples of Enteromorpha were taken in plastic bags with site-water for microscopic studies. Stones were Table 2. Cover ea le. also sampled for a closer investigation of the smaller algae Score Cover in the laboratory. All material was studied in fresh condition

within two days after sampling. All algae were studied by 0 0% light microscopy, notes were made of branching and 1

Acta Phytogeogr. Suec. 78 14 P. Snoeijs

Table 3. Specie li t with percentage weight (% W; weight = sum Table 4. Summary of te t variable and results of multiple of the cover score in the data et), frequency (F = number of regre sion analysis. occurrences in the 180 ite/dates), ea onal occurrence (Month), and abbreviation (Code). Taxa with W <1% are omitted. Minimum Maximum Unit Varies value value mainly with

Taxon o/oW F Month Code Predictor variable :

CYA OPHYTA A = Temperature anomaly 0 11 oc Site Phormidium sp. I 3 ------N PHO M = Water movement 0 6 0-6 scale Site Rivularia atra Roth 2 10 -----ASON RTV I = In alation (above surface) 25 520 11E m-2 s-1 Time RHODOPHYTA T = Background water temperature 19 oc Time Ceramium tenuicorne (Kiitzing) Wrern 6 MAMJJASON CER 1 N = N03-N 4 33 j.lg I-1 Time Polysiphonia nigrescens (Hudson) Greville 14 -AMJJASO - PN N0 -N 3 5 j.lg I-1 2 Polysiphonia violacea (Roth) Sprenger 8 ------0 PV P = P04-P I 9 !lg I-1 Time Si = Silicate 300 630 !lg I-1 Time CHROMOPHYTA (FUCOPHYCEAE) Chorda filum(L .) Stackhouse I 13 --MJJAS -- CHO Predictor variables¥ Min. Max. Ectocarpus siliculosus (Dillwyn) Lyngbye 2 17 -- MJ --SO ECT Dependent variable R2 I T A M value value Pilayella littoralis (L.) Kjellman 23 MAMJ ----- PIL Enteromorpha ahlneriana

CHLOROPHYTA (0-6 180 0.19 6 Cover scale) +++ +++ Capsosiphonfulvescens (C.A. Agardh) - ---- 128 0.21 0 50 4 -- JJ CAP Maximum length (cm) ++ Maximum width (mm) 128 0.08 0 0 0.2 23 Setchell & Gardner 128 0.35 0 0 72 438 C/adophorafracta (O.F. Muller) Kiitzing --MJJAS -- CF Cell size ().1m2) +++ + Cladophora glomerata (L.) Kiitzing 27 155 MAMJJASON CG Enteromorpha ahlneriana Bliding 20 128 MAMJJASO EA Enteromorpha intesrinalis Enceromorpha clathrata (0-6 180 0.31 0 5 (Roth) Greville 4 27 ---JJAS -- EC Cover scale) +++ 141 0.36 50 Enteromorplza inrestinalis (L.) Link 18 14 1 MAMJJASO El Maximum length (cm) +++ ++ I 141 0.24 0.2 75 Rhi;:.oclonium riparium (Roth) Harvey 4 31 ---JJASO RHI Maximum width (mm) Cell size ().1m2) 141 0.37 0 110 431 Spirogyra p. 3 27 ---JJ ---- SPI +++ +++ Ulothrix subjlaccida Wille 13 MAMJ ----- us Enteromorpha clathrara Ulothrix zonata (Weber & Mohr) Kiitzing 2 15 MAMJ --SO - uz (0-6 180 0.19 0 5 Cover scale) +++ + Maximum length (cm) 27 n.s. 5 30 Maximum width (mm) 27 n.s. 0.2 0.5 Cell size (J.!m2) 27 n.s. 203 522

180 0.43 Multiple regression analy is was applied to test degree of Cover Cladophora glomerata ++ +++ +++ Cover 180 0.09 0 0 cover, plant dimension , and cell size for the effects of Ceramium renuicome *** p ** p * p different environmental variables acting in combination S =Significance level : = < 0.001; = < 0.01; = < 0.05; n ..= not (Jongman et al. 1987). A ignificant regre sion coefficient significant. implies that the variable has a definite effect, when the other Re pon es to predictor variable in multiple regression analy i : Positive coefficient: +++ =p 0.00 I;++=p 0.0 I; += p 0.05; variable are held constant. < < < Negative coefficient: ---=p < 0.00 I; -- = p < 0.0 I; - =p < 0.05; 0 =no re ponse.

¥The nutrient concentrations have high positive correlations with each other and high negative correlation with in alation, therefore they cannot simultaneou ly be u ed a Results predictor variables in the multiple regre ion analy es.

Environmental factors

The site factors, temperature anomaly and water flow, also seasonal variation in nutrient concentrations during the showed some fluctuations in time. From April to September sampling period was illustrated by the analysed water sam­ part of the cooling water was discharged through the stand­ ples from site 2 (Table 4). The spatial variation was meas­ by outlet, therefore the sites (south-)west of the basin re­ ured only in November. The lowest concentrations for ceived more thermal input and the sites in the basin less nitrogen and phosphorus were generally measured in the 1 during this period than usual. In summer, the power plant area south-west of the basin (N03-N: 1 1-25 J.lg I- , P04-P: units were turned off (one at a time) for overhaul, which 1-3 J.lgI- 1 ); in the cooling water pathway and the area east of resulted in lower total thermal discharge in July and August. the basin the concentrations were slightly higher (N03-N: 1 1 Water temperatures were more influenced by air tempera­ 33-45 J.lgI- , P04-P: 1-9 J.lgI- ). N02-N varied from 4 to 7 ture at shallow sites with little water exchange than at sites J.lg 1-1 and silicate from 460 to 630 J.lg 1-1 , with variations with fast water flow, and thus relatively lower on cold days irrespective of the position of the sampling site. None of the (and vice versa). sampling sites had extremely high nutrient concentrations. Maximum background water temperatures occurred in Salinity was mostly 5.0 %o, and was always between 4.7 and July and August, maximum insolation in June. The seasonal 5.3 %o, except in March, when the melting ice cover caused cycle of nutrient concentrations is opposite to temperature extremely low salinities at some sites, e.g. 2.8 %o at site 10 and light (maximum from December to February). The and 3.7 %o at site 17.

Acta Phytogeogr. Suec. 78 Ecology and taxonomy of Enteromorpha species 15

Enteromorpha spp. and total community composition IS ites I 2 a. Altogether 30 macroalgal taxa were distinguished at the 180 site/dates; 18 taxa had � 1% weight in the dataset (Table 3). 5 1 0 Green algae dominated the communities in the upper littoral 20 1 6 • 0 in the area. The most abundant alga was Cladophora 18 4 • 1 9 1 glomerata, closely followed by Enteromorpha ahlneriana • 0 17 and E. intestinalis. These three form together with the red alga Ceramium tenuicornethe bulk of the hydrolittoral algal 0 0 1 0 9 vegetation throughout the year in the area; other algae are A rare or have a more distinct seasonal occurrence (Table 3).

8 Canonical correspondence analysis of species composi­ 0 7 tion data with respect to site and date (these were used as 0 !Months! 2 contraints) yielded two major ordination axes with eigen­ b. values 0.29 and 0.24 (compared with 0. 17 and 0. 12 for the third and fourth axes). Fig. 3 shows four kinds of informa­ tion from this analysis: centroids for all the samples taken at a given site; centroids for all samples taken in a given month; taxon scores; and vectors indicating the direction and rate of change in the environmental variables that were used passively in the ordination (temperature anomaly, water movement, insolation, nutrient concentrations and background water temperature). The site-points are differentiated according to the degree NOV of heating and water movement. The ten sampling sites receiving thermal discharge are situated on the left-hand I Species I 2 side of the ordination, and the ten unheated or only slightly c. CHO heated sites are on the right-hand side. The arrow for water 0 movement is very short (but still significant in the regres­ us 0 sion analysis performed by CANOCO); the unheated sites

C F with flowing water (sites 1 and 2) are disturbing the pattern. 0 The date-points depict the seasonal cycle of species compo­ PIL sition, which is mainly ruled by insolation, seasonal water Ec. 0 uz temperature and nutrient concentrations. Two relatively PV stable periods in spring and autumn are connected by a CER RIV0 0 PN period of more rapid change in summer. 0 The green algae Enteromorpha ahlneriana, E. clathrata, PHO 0 Cladophora glomerata and Rhizoclonium riparium showed the strongest positive responses to heating; negative re­ sponses were found for Ceramium tenuicorne (red), Polysiphonia nigrescens (red), Pilayella littoralis (brown), Fig. 3. Canonical correspondence analysis of macroalgal commu­ Chordafilum (brown), and the two Ulothrix species (green). nities with respect to site and time of year, showing (a) the Some species grew best in stagnant water (Enteromorpha centroids for sampling site (open symbols = unheated; closed spp., Cladophorafracta, Rhizoclonium riparium, Spirogyra symbols = heated), (b) the centroids for month (connected by lines), and (c) taxon scores. The arrows show the directions and sp., Capsosiphon fu lvescens), others at exposed sites rates of change for the environmental factors temperature anomaly (Ceramium tenuicorne,Polysi phonia nigrescens, Ulothrix (A), water movement (M), insolation above surface (1), back­ zonata). Artificial water flow promoted the growth of ground water temperature (T), and nutrient concentrations, N02-N Cladophora glomerata and Phormidium sp. in heated wa­ and silicate (Si). The taxon score of the + N03-N (N), P04-P (P) ter, and Chorda filum in unheated water. Most of these macroalgae with < 1% weight in the dataset are omitted; the three responses, including seasonality (Table 3) are reflected by Enteromorpha species are indicated by closed squares, the other the relative positions of the taxon scores in Fig. 3. But the taxa by open circles. For abbreviations see Table 3. increased cover of Cladophora glomerata by heating and water flow cannot be detected in the ordination.

Acta Phytogeogr. Suec. 78 16 P. Snoeijs

Enteromorpha ahlneriana

Cover <0-6 scale> Plant lengt h Plant width Cell size < p m2> 6 .------� 60 8 300.------,

5 F 50 F F F 6 40 20

30 4

100 2 10

0 0

6 �------� 60 8

5 E 50 E E 6 4

3 30 4

2 20 2

0 0 o��-�

60 8 ....------, 300,.------.,

5 s s 6 4

3 3 4

2 2

MJJASONo MAMJJASON A M J J A S 0 N o M��--� A M J J A S 0 N

Month

Fig. 4. Cover and dimensions of Enteromorpha ahlneriana (means of similar sampling ites according to Table 1 ). Open symbols apply to reference site (including slightly heated site ), closed ymbols apply to heated ite . F = flowing water; E =exposed sites; S = stagnant water. The natural situation is reflected by unheated, expo ed and stagnant sites.

Enteromorpha ahlneriana size of the pyrenoid (Figs. 4-5). In spring, numerous young sprout were observed to start growing from small older Under natural conditions E. ahlneriana was most abundant plants. Zoids were only ob erved in large amount in June, in summer and autumn, as shown by its easonal distribu­ which resulted in dense belts of new plants in July. During tion at exposed and stagnant sites (Fig. 4). Artificial heating the rest of the year no new generations of E. ahlneriana enhanced growth in winter, spring and autumn, but not in seemed to occur, and luxurious growth after a period of low summer, when the temperature anomaly in the cooling­ abundance was observed to start from small older plants water pathway was reduced to only a few °C. In water with (e.g. in September in flowing water). artificial flow conditions E. ahlneriana was almost com­ pletely absent in July and August, when Cladophora Enteromorpha intestinalis glomeratawas the only dominant species at such sites. Plant length varied more-or-less in concert with plant cover through Under natural conditions E. intestinalis was most abundant the year. The longest plants were found in stagnant water, in July and August (Fig. 6). Artificial heating had a large where also poorly attached floating mats occasionally were positive effect on plant cover only in artificially flowing found. Mostly the thallus of E. ahlneriana was rather nar­ water; in spring a positive effect was found also at exposed row (width 1-2 mm) and richly branched, but in autumn sites. The plants were longer at heated sites, and broader at broader specimens (width up to 23 mm) occurred at un­ unheated sites (except for exposed sites). The longest and heated sites. Such specimens were never encountered at the broadest plants (width up to 75 mm) were found in stagnant heated sites. Cell size was affected positively by heating water. The plants were basically unbranched or branched only in winter and early spring, and cells were smaller in near the base (forming a rosette), very seldom were there stagnant water. Cell size also varied with the season; the one or two branches higher up. Similar to E. ahlneriana the largest cells occurred from April to June, and they were cell size of E. intestinalis was affected positively by heating smallest in March and November, which is opposite to the only in winter and spring. The largest cells occurred from

Acta Phytogeogr. Suec. 78 Ecology and taxonomy of Enteromorpha species 17

E. ahlneriana E. ahlneriana E. intestinalis E. intestina lis unheated -site 14 heated - site 18 unheated -site 14 heated -site 6 M A R

MAY

JUN

JUL

AUG

SEP

Fig. 5. Cells of Enteromorpha ahlneriana and Enteromorpha intestinalis throughout the sampling period. Drawn from photographs of · living material .

Acta Phytogeogr. Suec. 78 18 P. Snoeijs

Enteromorpha intestinal is

Cover (0·6 scale> Plant length Ccm> Plant widt h Cell size C p m2> 6 60 36 400

5 F 50 F 30 F

4 40 24

3 30 18

2 20 100 10

0 0 0

6 60 36 400

5 E 50 E 3 E E

4 40 24

3 30 18

2

100

0

6 60 400

5 s 5 s s 300

3

2

100

A J J A s 0 N 0 M A M J J A s 0 N A M A s 0 N M A M A s 0 N

Month

Fig. 6. Cover and dimen ions of Enteromorpha intestinalis (cf. Fig. 4).

Enteromorpha clathrata

Cover C0-6 scale> Plant length Plant width Cell size < p m2> 6 60 .4 500

5 F 50 F F F 400 .3 4 40 300

3 30 .2 • • jl • 200 ~ 2 20 ..___ .1 100 10 0 0 0 0 0

6 60 .4 500

5 E E E E 50 400 .3 4 40 y' 300 3 30 .2 1\ 200 2 20 .1 100 10 /\ 0 0 0 0

6 60 .4 500

5 s s s s so- 400 .3 4 40 300 .2 3 30 jl jl jl • 200 2 20 .1 100 10

0 0 � 0 0 M A M A s 0 N M A M A s 0 N M A M J J A s 0 N M A M J J A s 0 N

Month

Fig. 7. Cover and dimen ions of Enteromorpha clathrata (cf. Fig. 4).

Acta Phytogeogr. Suec. 78 Ecology and taxonomy of Enteromorpha species 19

April to June, and they were smallest in March and Novem­ ber, in contrast to the size of the pyrenoid (Figs. 5-6). In stagnant water the cells were smallest. Swarmers were observed throughout the year, less often in the cold season, but even once in January at 11 oc (site 5). Many generations occurred throughout the year and very often narrow belts of different age were found growing c1ose to each other.

Enteromorpha clathrata

E. clathrata only occurred in summer, from June to Septem­ ber, and under natural conditions was mainly found in stagnant water (Fig. 7). Artificial heating generally en­ hanced growth, especially at exposed sites and sites with artificial water flow. Maximum plant length was shorter than in the other two species (only up to 30 cm). The thallus was branched and very slender (width mostly < 0.2 mm). In stagnant water E. clathrata often occurred in small poorly attached floating mats, but at sites with more water move­ ment it was firmly attached. No effect of heating on sizes of plant and cells was found. The cells were always larger than those of E. ahlneriana and E. intestinalis (Figs. 5 and 8a-d). The species was never really belt-forming, but on a few occasions completely overgrown stones (ea. 15 cm in diam­ eter) were found. Such dense populations may have emerged 50 pm from swarmers, which were observed in June only. Fig. 8. Cells ofEnteromorpha clathrata (a: Site 14, July 1991; b: Site 6, June 1991; c: Site 9, August 1991; d: Site 3, September Regression analysis 1991), Enteromorpha flexuosa ssp. paradoxa (e: Site 13, Augu t 1985; f: Site 18, October 1984), and Enteromorpha cf. compressa (g: Site 17, July 1991; h: Site 18, July 1984). The results of the multiple regression analyse are given in Table 4. The seasonal aspect is shown by trong positive correlations with seasonal background temperature for all three Enteromorpha species (maximum cover in summer). other environmental factors are shown. E. ahlneriana showed E. ahlne riana and E. clathrata also reacted posi ti vel y to an optimum at 13-21 °C, E. intestinalis at 19-24 °C, and artificial heating by increased plant cover; for the cover of E. clathrata at 22-27 °C.

E. intestinalis no reaction to heating was found. E. ahlneriana and E. intestinalis preferred quiescent water (negative cor­ Overwintering algae relation with water movement). No significant relation­ ships were found between plant dimensions and cell size of In January 1992 the ten sampling sites which never have an

E. clathrata. But E. ahlneriana and E. intestinalis showed ice cover in winter (Table 1) were visited. Because of the seasonality by correlations between plant length and sea­ warm winter 1991/1992 the two reference sites 7 and 8 sonal background temperature (longest plants in summer) (exposed sites east of the Biotest Basin) were not ice­ and between cell size and insolation (largest cells in early covered, and site 14 had only a thin ice cover. An ice cover summer). E. intestinalis reacted to artificial heating by > 10 cm thick occurred in the other seven sampling sites. growing longer, and the plants were both longer and broader Small plants of Ceramium tenuicorne and Urospora in quiescent water. Cell size had a positive correlation with penicillifo rmis (Roth) Areschoug, and a few threads of water movement for E. ahlneriana and E. intestinalis (small­ Ulothrix subflaccida were found at site 7. At site 8 no algal est cells in stagnant water). Cladophora glomerata showed vegetation was observed. At site 14 it was possible to make a positive response to artificial heating, and a clear seasonal a hole in the ice and no macroalgal vegetation was observed cycle with highest cover in summer. Ceramium tenuicorne in the field, but later some threads of V. subflaccida were had a negative correlation with artificial heating. fo und on a stone from this site by microscopic investigation. At the nine heated sites and site 2 (flowing water of 0 °C) Temperature optima the algal vegetation was dominated by diatoms in large colonies. At site 2 Melosira sp. and Berkeleya rutilans In Fig. 9 the mean cover scores of the three Enteromorpha (Trentepohl) Grunow dominated; at all other sites (6-12 °C) species for water temperature intervals, irrespective of the large colonies (up to 15 cm long) of Melosira monilifo rmis

Acta Phytogeogr. Suec. 78 20 P. Snoeijs

Cover <0-6 sea I e) Table 5. Overwintering Enteromorpha plants (20 January 1992). 4 E. ahlneriana Enreromorpha Enteromorpha ah/neriana intestinalis 3 Site WT COY LEN WID CSI COY LEN WrD csr

SITES WlTH ARTIFlCIAL U AL WATER FLOW

2 I ice 2 0.0 0 I * I 1.0 137 ± 7 3 9.S 2 12 .S 160± 11 I 2 1.0 !SI ± 12 O 4 7.0 2 12 I.S 139 ± 23 0 s 11.1 2 IS .S IS3 ± 16 2 ** 4 1.0 146± 12 O 6 12.0 2 12 o.s 77 ±S I 4 1.0 149 ± 8 0 MORE-OR-LESS EXPOSED SITES

4 7 0.2 0 0 E. intestinalis 8 0.2 0 0 9 ice

3 LO ice 11 ice 12 7.0 2 6 o.s 84 ± s 2 7 2.0 128 ± 13 13 9.9 0 2 3 1.0 14S ±6 2

SITES WITH MORE-OR-LESS STAGNANT WATER

••• 14 ice 0 0 IS ice 16 ice 0 17 ice 18 6.S I 2 0. 1 124 ± 8 2 6 1.0 ISS s 4 19 6.2 0 I s I.S 120 4 20 8.0 2 6 1.0 127 ± 18 2 s 2.0 137 s E. clathrata

WT Water temperature (0C) * = Dormant 3 COY Cover (0-6 scale, Table 2) ** = Swarmers observed LEN Maximum plant length (cm) *** = Very thin ice WID Maximum plant width (mm) ± 2 CS! Mean cell size (J..lm2) Standard deviation (n = 6).

Discussion 0 0 4 7 10- 13- 16- 19- 22 25- 3 6 9 12 15 18 21 24 27 oc Taxonomy

n = 9 17 17 21 43 28 29 9 7 The taxonomy of the genu Enteromorpha is complicated. Fig. 9. Mean cover of the three Enteromorpha species as a function Full-grown summer plants are easier to identify than tho e of water temperature, irre pective of site and time of year. The bars collected in other seasons. Mo tly, there is no problem to are standard errors. distinguish between the four sections in the genus Entero­ morpha (Koeman & van den Hoek 1982a, 1982b, 1984). However, identification to the species level is more diffi­ cult, despite the fact that the macroscopic morphology of the (O.F. Muller) C.A. Agardh covered >90% of the stones. plants is most distinctive between species within each sec­

Enteromorpha ahlneriana, E. intestinalis, or both species, tion (Koeman & van den Hoek 1982a, 1982b, 1984). Many were found at all ten sampling sites (Table 5). In 0 oc (site morphological aspects (e.g. branching, cell size, cell shape, 2) only two dark green dormant fragments of E. intestinalis size of the pyrenoids) also depend on environmental condi­ were found. But at the heated sites the Enteromorpha plants tions and time of year (Bliding 1963; this study). were healthy growing, lighter green, and mostly they had In the northern Baltic Sea at least six Enteromorpha larger cells and smaller pyrenoids than in November. species occur: E. intestinalis (L.) Link, E. compressa (L.) E. ahlneriana had the highest cover and the largest plants in Greville, E. prolife ra (O.F. Muller) J.G. Agardh, heated flowing water, and E. intestinalis at exposed sites E. ahlneriana Bliding, E. flexuosa (Wulfen ex Roth) and sites with stagnant water. Other overwintering algae (all J.G. Agardh, and E. clathrata (Roth) Greville (Wallentinus mainly in flowing water) were Cladophora glomerata 1979, Viitasalo 1984, Hallfors et al. 1987, Snoeijs 1987). (basal parts, 1 cm long), Rhizoclonium riparium, Ulothrix The study area (Forsmark) is relatively small (a few km2) subflaccida, and Urospora penicillifo rmis (the latter up to and receives no discharge of nutrients, which may explain 15 cm long, only at site 3). why the number of Enteromorpha spp. was limited. In this

Acta Phytogeogr. Suec. 78 Ecology and taxonomy of Enteromorpha species 21

study only three species, those that were common at Forsmark large cells in longitudinal rows and 2- 10 relatively small in 1992, have been studied in detail. pyrenoids. In the summer of 1984, I found at Fors mark the alga E. flexuosa ssp. paradoxa as shown by Eliding ( 1963), 1. Enteromorpha intestinalis (section Enteromorpha): but not in 1991. The two species can easily be separated when full-grown specimens are available. E. flexuosa (Fig. The plants were basically unbranched or branched only near 8e-f) has more robust plants, smaller cells and fewer the base (forming a rosette), very seldom with one or two pyrenoids than E. clathrata (Fig. 8a-d). broad branches higher up. The cells were unordered and possessed one pyrenoid and a cap-like chloroplast. It is not The size and morphology of especially E. ahlneriana, but easy to distinguish between E. intestinalis and E. compressa. also of E. intestinalis, varied very much both between and It has been proposed to combine them into one single within sampling sites and dates. It may be hypothesized that species (Silva & Burrows 1973, South & Hooper 1980), more than two species are involved, but in practice it was although this is not generally accepted (Koeman & van den impossible to distinguish any pattern whatsoever, which Hoek 1982a, Kornmann & Sahling 1983). On the Swedish would support the occurrence of more species. Besides the west coast, Eliding (1948, 1963) found a sterility limit few exceptions mentioned above, branching in E. intestinalis between the two species, as did Larsen (1981) from was always found in individuals with typical E. intestinalis different European localities. The general observation is cells, and the few unbranched E. ahlneriana plants had that E. intestinalis is unbranched with unordered cells typical E. ahlneriana cells. Such deviating plants were throughout, whereas E. compressa is branched with short always found within tight populations of typical specimens. curved cell rows between unordered cells. However, Wrern E. clathrata had a much more constant thallus morphology O (1952) found in the regrund Archipelago that most of the than the other two species. The border of the salinity range E. intestinalis plants are branched at the base and some have of this species is probably close to 5 %o judging from its one or two branches higher up (E. intestinalis sensu Ahlner small size at Forsmark compared with that in more marine 1877: Fig. 15 in Wrern 1952). Such branching of E. intesti­ conditions (Eliding 1944, 1963, Koeman & van den Hoek nalis may be caused by the low salinity in the area (Eliding 1 984). The absence of E. compressa and E. prolifera may be 1963). W remaccepted the name E. intestinalis for most of explained by the fact that none of the sampling sites was the material, except for a form from polluted water near enriched by nutrients. E. flexuosa was frequently found in sewers, which he identified as E. compressa. The bulk of my the summers of 1984 and 1 985 at Forsmark, but not in 1991; material resembled in all respects E. intestinalis as meant by the reasons for this absence are unclear. Wrern,but in 1984 I found some unbranched specimens at Traditional methods of culturing and cross-breeding ex­ Forsmark that may be E. compressa (Fig. 8h), and during periments, as performed by Eliding (1963), Larsen (198 1) thi study (1991) a specimen with two branches was found and Koeman & van den Hoek ( 1982a, 1982b, 1984 ), might with a tendency to cells in rows (Fig. 8g). throw some light on the taxonomic problems with the Baltic Enteromorpha forms. But it is more likely that only modern 2. Enteromorpha ahlneriana (section Proliferae): methods by studying genetic variability really can indicate The plants were unbranched to very richly branched, with where ecological variation stops and different species exist. cells basically arranged in longitudinal rows and one pyrenoid Such studies are highly recommended for this complicated of varying size. A few specimens of E. ahlneriana (site 12 in genus. March and April) macroscopically resembled E. prolifera, i.e. with a distinct main stem and numerous thin branches. But some features typical of E. prolife ra [including Ecology E. simplex (Vinogradova) Koeman & van den Hoek], occur­ rence of groups of 2-8 cells (Koeman & van den Hoek The responses of total algal community composition to the 1 982b) or a spirally twisted basal part (Kornmann & Sahling cooling water discharge in 1991 were comparable to 1984, 1983), were never observed. Wrern ( 1952) noted E. prolifera see Snoeijs & Prentice (1989) for an extensive discussion. only from water influenced by sewage, which also was Here I will concentrate on the Enteromorpha species and noted by Wallentinus (1979). Sometimes it was difficult to their most important competitors Cladophora glomerata distinguish between Cladophora glomerata and E. ahlneri­ and Ceramium tenuicorne. The other species in the upper ana in the field, but mostly Cladophora was heavily over­ littoral are rare or restricted to a certain season. grown with epiphytic diatoms, whereas Enteromorpha spp. Generally the heating effect was least in the middle of often were remarkably devoid of epiphytes. summer when the total thermal input was reduced. During the rest of the year E. ahlneriana was most enhanced by the 3. Enteromorpha clathrata (section Clathratae): cooling water, followed by Cladophora glomerata. A posi­ tive effect for E. intestinalis was only found in flowing The plants were always branched, and extremely slender water throughout the year, and at exposed sites in spring. (the width of the main axis was usually < 0.2 mm), with E. clathrata is exclusively a summer species, which may be

Acta Phytogeogr. Suec. 78 22 P. Snoeijs governed by water temperature; Koeman & van den Hoek Forsmark throughout the year mainly by swarmers (even in (1984) were not able to grow the species in cultures below January at 11 oc. Swarmers of E. ahlneriana were seldom 12 °C, and in Forsmark it never occurred below 14 oc. found (except in June) and, instead, luxurious vegetative The red alga Ceramium tenuicorne has a more narrow growth from small older plants was frequently observed. ecological amplitude than the green algae (with a strong Also Cladophora was observed to maintain a continuous preference for exposed localities), and it responds nega­ vegetative presence and produced zoospores only sporadi­ tively to artificial heating. Therefore C. tenuicorne loses cally. here in competition with the others despite its capability of The thallus of Enteromorpha intestinalis is simple fast growth (Wallentinus 1984) and perennial nature. (unbranched) and relatively broad. Both E. ahlneriana and Ice cover was identified as a crucial factor controlling Cladophora have thin filamentous thalli with larger surface/ timing and biomass of the vernal diatom blooms in the area volume ratios than E. intestinalis, and they may thus be (Snoeijs 1990). The absence of ice cover facilitates over­ capable of a faster nutrient uptake, resulting in faster growth wintering by increased light availability and no abrasion of (Wallentinus 1984). The largest within-species variation in the algae by ice-break. This favours especially those algal thallus morphology was found for the most opportunistic species that are capable of fast growth under relatively low alga E. ahlneriana; within reach of the cooling water the light and temperature conditions in early spring. Because of plants were always long, thin and very richly branched, the absence of any ice cover the algae do not become subject whereas under natural conditions the plants were less to a salinity-shock from ice-melting either. In the heated branched, slightly shorter and especially in autumn signifi­ water at Forsmark both E. ahlneriana and E. intestinalis cantly broader. Bliding (1944) already mentioned a very overwintered as small healthy plants. In the discharge area variable thallus as one of the characteristics of the species. of the Olkiluoto power plant on the Finnish Baltic Sea coast, Also E. intestinalis often had a longer and thinner thallus at Keskitalo & Heiitto ( 1 987) also found tufts of E. ahlneriana heated sites, but it cannot expand its surface by numerous in January 1986. The capability of overwintering in good thin branches as E. ahlneriana does. vegetative conditions can thus explain the enhanced cover Cell size decreases with higher salinity (Koeman & van of E. ahlneriana and E. intestinalis in heated sites in early den Hoek 1982a, 1982b, 1984), a richer supply of nutrients spring. At the unheated site with no ice cover (site 2), (Bliding 1963), and less water movement (this study). It E. intestinalis was fo und in January as small loose-lying, seems that generally the plants become larger, and the cells dormant fragments, similar to observations in March of both smaller, when environmental factors are beneficial for E. ahlneriana and E. intestinalis at reference sites with ice Enteromorpha species. But the seasonal size vruiation of the cover in winter. The temperature anomaly of 6- 12 oc seems cells is the reverse, with the largest cells when most light is thus necessary for the overwintering of the Enteromorpha available (June), and small cells in winter. species as healthy plants, and the low level of insolation in Being uniseriate, the surface/volume ratio of Cladophora January does not prevent the plants from growing. How­ glomerata is larger than that of any Enteromorpha species, ever, no high cover was ever found for the Enteromorpha but Cladophora is mostly heavily overgrown by epiphytic species in mid-winter (maximum cover 5%), when large diatoms, whereas Enteromorpha spp. are not. This may be diatom colonies occurred with >90% cover. The diatoms explained by the regular shedding of the outer cell wall have lower temperature optima: e.g. Berkeleya rutilans, layers of Enteromorpha, which helps to prevent the build­ which is dominating in the intake channel in January, was up of epiphytes (McArthur & Moss 1977). The thick layers shown to have an optimum abundance at 2-4 °C, and of diatoms on Cladophora decreased the light that reaches Melosira moniliformis, which dominates at all heated sites, the macroalga. Within reach of the cooling-water, the growth at 6- 12 oc (Snoeijs 1990). Among the Enteromorpha spe­ of epiphytic diatoms is promoted (Snoeijs 1989, 1990). This cies, E. ahlneriana has the lowest optimum (13-2 1 °C). The is disadvantageous for Cladophora and other algae that diatom colonies reached a length of up to 15 cm, and thus easily are invaded by diatoms, but advantageous for also inhibited light reaching the Enteromorpha tufts. Enteromorpha spp. Especially in heated flowing water, Cladophora is overwintering by its still firmly attached large Cladophora plants were observed to first turn brown basal parts, these were colourless (dormant) at 0 °C, but of diatoms, then yellow and unhealthy, after which they green and up to 1 cm long at the heated sites. They were, were ripped off near the base, and the upper part disap­ however, completely overgrown by epiphytic diatoms. peared with the water flow. In the meantime E. ahlneriana The means of propagation in Enteromorpha spp. may was still healthy green and attached at the same sites. partly explain why Enteromorpha ahlneriana is promoted Cladophora, on the contrary, has an advantage when the by cooling water discharge throughout the year, and water flow is so fast that Enteromorpha and most epiphytes E. intestinalis only in spring (except in flowing water). cannot remain attached. The attachment of Cladophora E. ahlneriana has only asexual swarmers (zoids), whereas seems to be stronger. This was the case at site 4 from June to

E. intestinalis (as well as E. clathrata) has alteration of September when pure stands of dark-green, ea. 30 cm long, generations by male and fe male gametes and zoids (Bliding rather stiff C. glomerata occurred at flow rates >3 ms-1 • 1963, Evans & Christie 1970). E. intestinalis propagated at

Acta Phytogeogr. Suec. 78 Ecology and taxonomy of Enteromorpha species 23

Acknowledgements. I thank Prof. Inger Wallentinus for 70. critically reviewing this paper. This study was financed by Koeman, R.P.T. & van den Hoek, C. 1984. The taxonomy of the Swedish Environmental Protection Agency (SNV), and Enteromorpha Link., 1820, (Chlorophyceae) in the Nether­ lands. Ill. The sections Flexuosae and Clathratae and an I am very grateful to Prof. Ulf Grimas (SNV) for giving me addition to the section Proliferae. - Cryptogamie Algol. 5: the opportunity to work at Forsmark. 21-61. Kornmann, P. & Sahling, P.H. 1983. Meeresa1gen von Helgoland - Benthi che Grlin-, Braun- und Rotalgen. Westholsteinische Verlagsdruckerei Boyens & Co., Heide. 289 pp. Larsen, J. 1981. Crossing experiment with Enteromorpha References intestinalis and E. compressa from different European locali­ ties. - Nordic J. Bot. 1: 128-136. Ahlner, K. 1877. Bidrag till kannedomen om de Svenska formema McArthur, D.M. & Moss, B.M. 1977. The ultrastructure of cell af algslagtet Enteromorpha. - Akademisk Afhandling, Cen­ walls in Enteromorpha intestinalis (L.) Link. - Br. Phycol. J. tral-Tryckeriet, Stockholm. 51 pp. 12: 359-368. Eliding, C. 1 944. Zur Systematik der schwedischen Enteromorphen. Peussa, M. & Ravanko, 0. 1975. Benthic macroalgae indicating -Bot. Not. 1944: 33 1 -356. changes in the Turku Sea area. - Merentutkimuslait. Julk. Eliding, C. 1948. Ober Enteromorpha intestinalis und compressa.­ Havsfor kningsinst. Skr. No. 239: 339-343. Bot. Not. l948: 123- 136. Snoeijs, P. 1985. Microphytobenthic biomass and environmental Eliding, C. 1963. A critical survey of European taxa in Ulvales, data in and around the Forsmark B iotest Basin 1983- 1 985. - Part I. Capsosiphon, Percursaria, Blidingia, Enteromorpha. Medd. Vaxtbiol. Inst. 1985: 2, Uppsala. 76 pp. -Opera Bot. 8(3): 1-160. Snoeijs, P. 1987. Epilithic algal assemblages in the Forsmark de Silva, M.W.R.N. & Burrows, E.M. 1973. An experimental Biotest Basin. - SNV-Report 3355, Swedish Environmental assessment of the status of the species Enteromorpha intestinalis Protection Agency, Solna. 81 pp. (L.) Link and Enteromorpha compressa (L.) Grev. - J. Mar. Snoeijs, P.J.M. 1989. Ecological effects of cooling water dis­ Bioi. Ass. U.K. 53: 895-904. charge on hydrolittoral epilithic diatom communities in the Evans, L.V. & Christie, A.O. 1970. Studies on the ship-fouling northern Baltic Sea. - Diatom Res. 4: 373-398. alga Enteromorpha. 1. Aspects of the fine structure and bio­ Snoeijs, P.J.M. 1990. Effects of temperature on spring bloom chemistry of swimming and newly-settled zoospores. - Ann. dynamics of epilithic diatom communities in the Gulf of Bot. 34: 45 1 -466. Bothnia. - J. Veg. Sci. 1: 599-608. Grimas, U. 1 979. The Biotest Basin of the For mark nuclear power Snoeijs, P.J.M. & Prentice, I.C. 1989. Effects of cooling water plant, Sweden. In: Methodology for assessing impacts of discharge on the structure and dynamics of epilithic algal radioactivity on aquatic ecosy terns. - Technical Reports communities in the northern Baltic. - Hydrobiologia 1 84: 99- Series No. 190, pp. 217-226. IAEA-AG- 1341 10, IAEA, 123. Vienna. South, G.R. & Hooper, R.G. 1980. A catalogue and atlas of the Hallfors, G., Viitasalo, I. & Niemi, A. 1987. Macrophyte vegeta­ benthic marine algae of the I land of Newfoundland. - Me­ tion and trophic statu of the Gulf of Finland - A review of morial Univ. Newfoundland Occ. Pap. Bioi. 3: 1-136. Finnish investigations. - Meri 13: 111-158. ter Braak, C.J.F. 1986. Canonical correspondence analysis: a new Hayren, E. 1921. Studier over fOroreningens inflytande pa stran­ eigenvector technique for multivariate direct gradient analy­ demas vegetation och flora i Helsingfors hamnomrade. - sis. - Ecology 67: 1 167- 1 179. Bidr. Kanned. Finlands Nat. Folk 80(3): 1-128. (With German Viitasalo, I. 1984. Changes in the littoral vegetation of a brackish­ summary.) water bay near Hel inki, Finland, fo llowing conversion of the Jongman, R.H.G, ter Braak, C.J.F. & van Tongeren, O.F.R. 1987. sewage outlet system. - Ophelia, Suppl. 3: 253-258. Data analysis in community and landscape ecology. - Pudoc, Viitasalo, I. 1990. The state of littoral submerged vegetation in the Wageningen. 299 pp. Helsinki and Espoo Sea areas in 1988. Comparison with the Kautsky, L. 1982. Primary production and uptake kinetics of years 1979 and 1984. - Rep. Water Conserv. Lab. 18, Hel­ ammonium and phosphate by Enteromorpha compressa in an sinki. 33 pp. (In Finnish, with English summary.) ammonium su1fate industry outlet area. - Aquat. Bot. 12: 23- Wallentinus, I. 1979. Environmental influences on benthic 40. macrovegetation in the Trosa-Asko area, northern Baltic Keskitalo, J. & Heiitto, L. 1987. Overwintering of benthic vegeta­ proper. II. The ecology of macroalgae and ubmersed tion outside the Olkiluoto nuclear power station, west coast of phanerogams. - Contr. Asko Lab. Univ. Stockholm 25: 1- Finland. - Ann. Bot. Fenn. 24: 23 1 -243. 210. Keskitalo, J. & llus, E. 1987. Aquatic macrophytes outside the Wallentinus, I. 1984. Comparisons of nutrient uptake rates for Olkiluoto nuclear power station, west coast of Finland. - Baltic macroalgae with different thallus morphologies. - Ann. Bot. Fenn. 24: 1-21. Mar. Bioi. 80: 215-225. Koeman, R.P.T. & van den Hoek, C. 1982a. The taxonomy of Wcern,M. 1952. Rocky-shore algae in the bregrund archipelago. Enteromorpha Link, 1820, (Chlorophyceae) in the Nether­ -Acta Phytogeogr. Suec. 30: XVI + 298 pp. lands. I. The section Enteromorpha. - Arch. Hydrobiol., Suppl. 63: 279-330. Koeman, R.P.T. & van den Hoek, C. 1982b. The taxonomy of Enteromorpha Link, 1820, (Chlorophyceae) in the Nether­ lands. II. The section Proliferae. -CryptogarnieAlg ol. 3: 37-

Acta Phytogeogr. Suec. 78

Effects of nutrient enrichment on planktic blue-green algae in the Baltic Sea

Kerstin Wallstrom1, SifJohansson & UlfLarsson2

Abstract

Wallstrom, K., Johansson, S. & Larsson, U. 1 992. Effects of nutrient enrichment on planktic blue­ green algae in the Baltic Sea. - Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-7210-078-8.

Effect of exce s phosphorus in relation to nitrogen on blue-green algae in a coastal area of the Baltic Sea were tudied in five 1000 I pla tic bag , Augu t-September 1988. The ame amount 3 1 of nitrogen, 4.5 mg NH4-N m- day- , was added to all bags, and phosphoru wa added in 3 1 concentrations of 0 . 5, 1, 2, 4 and 8 mg P04-P m- day- • The experiment started with addition of both nutrients for 14 days and continued with only phosphorus additions for another 14 days. Aphanizomenon flos-aquae, initially constituting 13% of the total phytoplankton biomass, disappeared almost completely during the first two weeks in all bags. The population ofNodularia spumigena increased during the experiment and relatively slow growth rates, with a maximum doubling time of four days, were probably caused by water temperatures below optimum. On the basis of the estimated growth rate of N. spumigena at different nutrient conditions, it is suggested that N. spumigena i superior to A. flos-aquae in competition for phosphorus. A succession in dominance of A. flos-aquae and N. spumigena at decreasing phosphorus supply during the nitrogen-fixing ea on can thus be explained by differences in competitive abilities for phospho­ rus. In the experiment, Oscillatoria limnetica increased in biomass only as long as both nitrogen and phosphorus were supplied. This is in agreement with 0. limnetica being unable to fix atmospheric nitrogen and that the pecies normally is found in nutrient-rich coastal areas of the Baltic Sea.

Keywords: Aphanizomenonjlos-aquae; Bag experiment; Growth rate; Nodularia spumigena; Ks ; Oscillatoria limnetica; Phosphorus.

' Department of Ecological Botany, Uppsala University, Box 559, S-751 22 Uppsala, Sweden. 2Department of Systems Ecology, Section Marine Ecology, Stockholm University, S-106 91 Stockholm, Sweden.

Introduction Besides, some strains of blue-green algae are highly toxic (Edler et al. 1985). In order to avoid mass occurrence of Blue-green algae usually make up a large part of the summer blue-green algae in coastal areas, the total of nutrient dis­ phytoplankton community in the Baltic Sea. Different spe­ charges must be restricted and the ratio between nitrogen cies dominate in different areas depending on nutrient con­ and phosphorus in point source discharges adjusted so as to ditions. Nitrogen-fixing species are frequent in coastal areas become unfavourable for nitrogen fixing species (Wallst rom receiving nutrient discharges of low N:P ratio (Rinne et al. 1988). 1981)as well as in nutrient-poor areas of the open Baltic Sea In August-September, 1988, an enrichment experiment proper which are characterized by a small excess of inor­ was performed with the natural phytoplankton community ganic phosphorus and a deficiency of mineralized nitrogen of the Baltic Sea proper in order to study effects on blue­ (Wallstrom 1991). In coastal areas with a high supply of green algae of increased supply of phosphorus in relation to both nitrogen and phosphorus, non-nitrogen-fixing blue­ nitrogen. The experiment was focused on nitrogen fixing green algal species of Oscillatoria and Microcystis domi­ algae with the main objective to estimate species-specific nate (Melvasalo & Viljamaa 1977, Kaiser et al. 1981, requirements for phosphorus. Improved knowledge of blue­ Nordling 1984). green algal nutrient demand will increase our ability to Mass occurrence of blue-green algae is considered a predict species composition at certain nutrient conditions nuisance. Recreational values of water are obviously low­ and, vice versa, to use specific species as indicators of the ered when bloom populations accumulate at the surface. nutrient conditions in an area.

Acta Phytogeogr. Suec. 78 26 K. Wallstrdm et al.

Table 1. Addition of nutrient (mg m-3day-1 ) to bags V. a) I- 20 ·c -Temp bag I I Day 1-14 Day IS-22

Bag NH4- P04-P NH4-N P04-P 18 I 4.S O.S 4.5 I 16 11 m 4.5 2 2 IV 4.5 4 4 14 V 4.5 8 8

12

10

0 s 10 IS 20 25 30 days Material and Methods

b) The experiment was carried out in the northern Baltic Sea - - (+0.5 mg P) e I proper at the Asko Laboratory 70 km south of Stockholm, 10 -n(+l mg P) ------3 (") (+2 mg P) Sweden. Five plastic bags of 1m (0 65 cm, depth 3 m) were I Ill E IV (+4 mg P) filled with unfiltered surface water on 9 August 1988 (day 0£) V (+8 mg P) 0). The experiment continued for four weeks. Due to the E large izes of the bag no replicates were possible. Nitrogen z (NH Cl) and phosphorus (N HP0 ) were added daily dur­ 0£) 4 � 4 I-. s 0 ing the first 14 days, but only phosphorus during the follow­ c ing 7 days (Table 1). In bag I, nutrients were added only during the first 14 days. The nutrient additions to bag I, 4.5 3 1 3 1 mg NH4-N m- day- and 0.5 mg P04-P m- day- , were expected to maintain an average primary production of 100 mg C m-3 day-1 , which i normally found in the area during 0 S 10 IS 20 2S 30 days Augu t (Larsson & Hagstrom 1982). Surface temperature and Secchi di c depth were meas­ c) ured every morning around 10 a.m. Sampling for analyses of phytoplankton and nutrient were u ually performed every 4th day before the daily addition of nutrients. Samples 1000 were taken in the upper 2 m water column of each bag with a tube sampler of 12 1 volume. After sampling, unfiltered \' 100 urface water from outside the bags was added to compen­ 0£) 5 sate for water lo s and the water was carefully stirred. 0;- 10 Water concentrations of inorganic nitrogen and pho pho­ 0 rus were analysed immediately after sampling according to 0... slightly modified method ofGrasshoff et al. (1983). Phyto­ plankton samples were preserved in Lugol's solution sup­ ()_ n.d. "$ plemented with acetic acid. Species composition and biomass 0. 1 were analyzed using an inverted microscope according to 0 S 10 IS 20 2S 30 days Edler ( 1 979). Mean filament lengths of Nodularia spumigena Mertens ex Bornet & Flahault were estimated from meas­ urements of at least 50 specimens or from a total filament Fig. 1. (a) Surface water temperature in bag L (b) Total concentra­ length of at least 5 000 J..lm in each bag. Maximum growth tion of all fractions of inorganic nitrogen (N03-, N02- and NH4-N) rate con tants ( ) were estimated from the slope of the in bags I-V. Bag I is denoted with a broken line because the period J..lmax of nutrient additions was only 14 days (Table 1). Indicated phos­ logarithmic (1n) growth curve during the exponential growth phorus value for each bag corresponds to additions in mg P04 - P phase (Ahlgren 1988). m-3 day-1 • (c) Concentration of inorganic phosphorus in bags I-V. n.d. = non detectable value. Note that the concentration of phospho­ rus is given in a logarithmic scale.

Acta Phytogeogr. Suec. 78 Ef fects on nutrient enrichment on blue-green algae 27

1200 -r------,------, +P Phytoplankton biomass and species composition

- Ell Total phytoplankton biomass increased in all bag during "i'E the first 10-14 days when both nitrogen and pho phoru Of) 800 5 were added. In the second part of the experiment, when only en en ro pho phorus was added, total bioma s decreased slightly and E 0 then remained fairly constant in all bags except for bag V. In :.0 400 this bag biomass doubled between days 14 and 16 and then remained at a level twice that of the other bag (Fig. 2). At the start of the experiment the phytoplankton commu­ nity was dominated by small ( <5J.1m)flage llates (70% of the 0 5 10 15 20 25 30 bioma ), Aphanizomenon flos-aquae Ralfs ex Bornet & days Flahault (13%), Oscillatoria limnetica Lemmermann (9%) and Nodularia spumigena (4%) (Fig. 3). During the fir t 14 Fig. 2. Total phytoplankton biomass (wet weight) for bags The 1-V. day the relative biomas of limnetica, Katodinium p., vertical line indicate the hift in daily nutrient additions. 0. Pyramimonas p. and Monoraphidium sp. increased at the cost of small flagellates and A.flos-aquae. Species compo­ sition with time was very similar in all bags although ome differences in the relative proportion of specie occurred. The high phytoplankton bioma s in bag V at the end of the Results experiment was a result of an increase of small flagellate between days 14 and 16. At the end of the experiment, Gymnodinium sp. and Monoraphidium sp. dominated in Environmental conditions bags 11-IV, whereas Gymnodinium sp. and small flagellates dominated in bag V. The temperature as measured in bag I fluctuated between 12_7 and 16.4 oc (a mean of 15.2°C) during the experiment (Fig. la). The Secchi disc depth varied between 1.4 and 2.1 Blue-green algae m. Low concentration of inorganic nitrogen, mainly N03- N, were measured in all bags, varying between 1.4 and 6 mg Wherea the three blue-green algal species differed in bio­ -3 ma development with time, each species had a similar m (Fig. 1 b). The concentration of inorganic phosphorus increased with increa ed additions. In bag I, the concentra­ biomass development in all bag , i.e. the changes in tion of phosphoru was non-detectable on day 14, which biomass seemed to be independent of the concentration of was the la t day of nutrient addititions in this bag (Fig. le). phosphorus.

+N +P +P % 100 Bag II

D flagellates <5Jlm • Monoraphidi urn • Pyramimonas 50 D Katodinium D Gyrnnodinium Oscillatoria D Nodularia • Aphanizomenon

Fig. 3. Relative bioma s (wet weight) of the 5 10 15 20 25 30 dominating phytoplankton genera in bag 11. days The vertical line indicate the shift in daily nutrient addition .

Acta Phytogeogr. Suec. 78 28 K. Wallstrom et al.

a) Nodularia spumigena Aphanizomenon flos-aquae 1000 +N +P +P 20 ,------r------� +N +P +P 6 6 -- e- - I ( +0.5 mg P)

-- e- - I ( +0.5 mg P) -5 01} --- n (+ I mg P) c:: � III (+2 mg P) E 500 IV (+4 mg P) (!) V (+8 mg P) � � t: ro (!) E

0 0 5 10 15 20 25 30 0 5 lO 15 20 25 30 days days Fig. 5. Mean fi lament length of Nodularia spumigena in bags I, II, Ill and V. b) Nodularia spumigena 50 ,------r------� +N +P +P

'�'a Aphanizomenon flos-aquae decreased dramatically dur­ 01} g ing the first 14 days (Fig. 4a). At the end of the experiment, <:/) <:/) A. flos-aquae increased slightly in bags I, II and V, but 6 25 remained low. :00 In contrast to A. flos-aquae, Nodularia spumigena in­ creased during the first 16 days, but least in bag I (Fig. 4b ). In bags II, Ill and V the biomass was about the same until day 16, but at the end of the experiment the biomass was 0 3 highest in bag Ill (42 mg wet weight m- ). In bag IV, the 0 5 10 15 20 25 30 biomass of N. spumigena was too small to be determined days accurately. The mean lengths of the filaments of N. spumigena were c) 0 cillatoria limnetica less than 150 11-mdur ing the fi rst 14 days. At the end of the 400 +N +P +P experiment the mean length increased to 500 11-m (bags II ,.-.., and V) and 860 11-m(ba g Ill) (Fig. 5). � Oscillatoria limnetica responded yet in another way. The eo biomass increased during the first period with additions of g both nitrogen and phosphorus but declined during the sec­ � 200 ro ond part of the experiment, when only phosphorus was E :00 added to the bags (Fig. 4c).

Growth estimates 0 5 10 15 20 25 30 Fig. 6 is an example of the normal and logarithmic (In) days biornass curve of Nodularia spumigena and Oscillatoria limnetica. In this example exponential growth was assumed Fig. 4. Biomass (wet weight) ofAphanizomenonjlos-aquae in bags to occur between days 10-16for N. spumigena and between I-V (a), Nodularia spumigena in bags I, II, Ill and V (b) and days 1-14 for limnetica. Maximum growth constants Oscillatoria limnetica in bags I-V (c). 0. estimated for these algae are given in Table 2. (11-maJ In all bags N. sp umigena had a lag phase of 10-14 days before exponential growth. In bag I 11-max was less than half of 11-max in bags II, ill and V, corresponding to a doubling time of approximately 9 and 4 days respectively. 0. limnetica responded rapidly to the nutrient additions and grew exponentially from the start of the experiment. The 11-maxfor 0. limnetica varied between 0.20 and 0.29, resulting in a doubling time of approximately 3 days.

Acta Phytogeogr. Suec. 78 Effe cts on nutrient enrichment on blue-green algae 29

Table2. Estimated and doubling time of Nodularia spumigena Jlmax a) and Oscillatoria limnetica in bag with different phosphoru addi­ Nodularia pumigena, bag li tions. The addition of inorganic nitrogen wa the same for all bag 3 1 (4.5 mg NH4-N m- day- ). 20 ,-... Bag P04-P Days with Doubling J.lmax (mg m-3 day- 1) (ct-1) exp. growth time (d) '76 b.() 15 Nodu/aria 5 VJ I 0.5 0.08 0.982 3 14-22 9.0 VJ ro 6 10 11 0. 17 0.978 10-16 4. 1 :00

lii 2 0. 19 0.983 10-16 3.6 5

V 0. 18 0.937 10-16 3.9 0

Oscillatoria 0 5 10 15 20 25 30 I 0.5 0.24 0.904 4 1-14 2.9 b) 11 0.22 0.98 1 4 1-14 3.2 Oscillatoria limnetica, bag li 200 2 0.26 0.984 1-10 2.7 rn --e- IV 4 0.20 0.975 1-10 3.5 150 ,-... VJ VJ V 8 0.29 0.957 1-10 2.4 \ ro b.() 100 6 5 :00 VJ .5 VJ ro 50 E :.00 0

Discussion -50 0 5 10 15 20 25 30 The total phytoplankton biomass increased when both nitro­ days gen and phosphorus were supplied. The shift to addition of Fig. 6. Normal and logarithmic growth curves (biomass in wet phosphorus only resulted in interrupted biomas increase weight) for Nodularia spumigena (a) and Oscillatoria limnetica (b) and changed species dominance, stres ing the importance in bag ll. of both total concentration and relative proportion of nutri­ ents as factors determining the development of the phytoplankton community. The fact that total phytoplankton experimental set-up was unfavourable for the pecies. Fur­ biomass in each bag did not increase in relation to added ther, the nitrogen supply during the first part of the experi­ concentration of phosphorus indicates that the phytoplankton ment may have had a negative influence on the biomass community of the experiment was not limited by phospho­ formation of A. flos-aquae as shown in other enrichment rus. Probably, the phytoplankton community was initially experiments (Riddolls 1985, Istvanovics et al. 1986). The limited by the availability of nitrogen, but as both phospho­ light biomass increase in some of the bags at the end of the rus and nitrogen were supplied during the first 14 days when experiment, when no nitrogen had been added for two the biomass increased, we cannot exclude that both nutri­ weeks, supports the latter explanation. ents limited phytoplankton growth. The results are consist­ The other nitrogen fixing species, Nodularia spumigena, ent with the commonly-held opinion that nitrogen is the was not negatively affected by the presence of inorganic predominant nutrient limiting primary production in the nitrogen as biomass increased during the period of nitrogen Baltic Sea proper, and that low availability of both nitrogen additions. An apparent termination of biomass increase at and phosphorus can limit phytoplankton during summer the end of the experiment was inconsistent with a contem­ blooms of blue-green algae (Gram!li et al. 1990). porary increase in filament length, indicating active growth When phosphorus was in excess in relation to nitrogen, of the population (Figs. 4b and 5). We suggest that these nitrogen fixing algae should be favoured by nutrient condi­ contradictory results are an effect of a population composed tions. However, as both nitrogen and phosphorus were of filaments of varied age and that the increase in biomass continuously added to the bags during the first 14 days of provided by new filaments was more or less equal to the loss experiment, a severe nitrogen deficiency could not be ex­ of biomass caused by dying filaments. pected. The rapid disappearance of the nitrogen fixing The biomass of N. spumigena reached a maximum level Aphanizomenon flos-aquae during this period has two of 42 mg m-3 (bag Ill, Fig. 4b ). This was approximately half probable explanations. First of all, it is possible that the the mean value of the N. spumigena biomass at 0-20 m depth

Acta Phytogeogr. Suec. 78 30 K. Wallstrom et al.

at nine stations in the open Baltic Sea proper during a bloom N. spumigena in the bag experiment thus indicate a in 1982 (Wallstrom in press). The environmental conditions superior competitive ability for phosphorus. Differences in in the surface layer during the Nodularia bloom in 1982 phosphorus requirements can explain the seasonal succes­ were characterized by a low concentration of inorganic sion of A. jlos-aquae and N. spumigena in the Baltic Sea nutrients and a water temperature of20-2 1 °C (Thorstensson proper. In the beginning of the summer A.jlos-aquae domi­ in press). In the experiment, the relatively low temperature, nates over N. spumigena, whereas the latter increases in a mean of 15.2 °C, probably suppressed the growth rate of abundance later on (Lindahl et al. 1978), when the pool of N. spumigena, which is known to require water tempera­ exces phosphoru ha decrea ed due to consumption. tures of at least 17 oc to reach bloom conditions (Hlibel & In the experiment, Oscillatoria limnetica increased in HUbel 1980). biomas as long as both nitrogen and phosphoru were The growth rate of a species increases with temperature, supplied, but was not able to compete successfully when but the lower sub trate limit at which maximum growth rate nitrogen additions were stopped. As 0. limnetica lacks i attained seems to be independent of temperature (Ahlgren heterocysts, it is usually not considered as a nitrogen fi xing

1987). Hence, although the growth rate of N. spumigena species, although nitrogen fi xation has been demon t.rated was not at absolute maximum for the pecies due to a to occur in some strains of Oscillatoria (e.g. Stal & Heyer relatively low temperature, some basic information regard­ 1987). Apparently there was no significant nitrogen fi xation ing the phosphorus requirements of N. spumigena is given by 0. limnetica in this experiment as the species did not in the experiment. N. spumigena grew at maximum rate in survive the nitrogen deficient part of the experiment. bags II, Ill and V (Table 2). Thus, the lower phosphorus Our result are supported by the fact that Oscillatoria limit for maximum growth was equal to or lower than the species are frequent in in-shore areas of the Baltic Sea which phosphorus supply in bag II which received the lowest are characterized by high loading of both nitrogen and pho phorus addition. In this bag, the mean water concentra­ phosphoru (Niemi 1976). Faster response to nutrient addi­ tion of inorganic phosphorus was 1 mg m-3 during the time tions and a higher growth rate of Oscillatoria limnetica than of exponential growth, i.e. days 10- 16 (Fig. le). Momen­ of Nodularia spumigena results in lower competition ad­ tarily following nutrient addition, however, the phosphorus vantages of N. spumigena in nutrient-rich conditions, al­ supply was doubled. though both species obviously grow well when both nitro­ In bag I the growth rate constant of N. spumigena was gen and phosphorus are available. approximately half of the maximum rates in the other bags It has been difficult to demonstrate changes in phyto­ (Table 2). According to the definition of the half saturation plankton composition or biomas a an effect of the increa - constant (K5), i.e. the nutrient concentration which can ing eutrophication that ha taken place during the 20th upport a growth rate which i half of the maximum growth century in the Baltic Sea (Elmgren 1989). However, ome rate, the pho phorus concentration in bag I was equal to K5 change in the relative abundance of blue-green algal pe­ during the period of exponential growth of N. spumigena. cies can be connected to large-scale changes in nutrient N. spumigena began to grow exponentially in bag I on day condition . In coastal areas of the outhern Baltic Sea, for 14, which was the last day of nutrient addition in that bag. example, Aphanizomenon jlos-aquae dominated the urn­ Before the nutrients were added, the phosphorus concentra­ mer phytoplankton community in the beginning of the tion in the water wa non-detectable (Fig. le). Thu , during century (Apstein 1902). Today, the same areas are totally the course of exponential growth of N. spumigena the dominated by Microcystis aeruginosa (Klitz.) KUtz. as an phosphorus demand of the whole phytoplankton commu­ effect of increased nutrient loading from land areas (Wiktor nity in bag I had to rely on that single addition of 0.5 mg & Plinski 1975, Borysiak & Ringer 1982). With improved 3 P04-P m- . Other phosphorus sources such as the supply knowledge on species-specific nutrient demand it is possi­ from nutrient recycling were probably important for the ble to analyse, in a more comprehensive way, the effects of pho phorus demand of the algae in this bag. From these eutrophication on the basis of phytoplankton species com­ results we conclude that the K5 value of N. spumigena for position and abundance. Further, the knowledge of phyto­ 3 phosphorus is well below 0.5 mg P04-P m- . plankton nutrient demand in combination with information Nodularia spumigena often occurs together with on phytoplankton distribution given in the literature will Aphanizomenon jlos-aquae in the summer blooms of the provide a useful tool in analyses of eutrophication develop­ Baltic Sea proper. The availability of pho phorus is decisive ment in the Baltic Sea during the last century. for the growth of both species due to the ability of the species to utilize atmospheric nitrogen, assuming that no other essential substance is deficient. The relative abilities Acknowledgements. Our warmest thanks are due to Gunnel of N. spumigena and A. flos-aquae to compete for phospho­ Ahlgren, Department of Limnology at Uppsala University, rus can be illustrated by the half saturation constant (K5) of for her advice on calculation of phytoplankton growth rates respective species. The K value of A. jlos-aquae for phos­ and for reviewing the manuscript. The study was financed phorus has been estimated to 1.5 mg m-3 (Uehlinger 1981). by grants from the Swedish Environmental Protection 3 The estimated Ks value of <0.5 mg P04-P m- for Agency.

Acta Phytogeogr. Suec. 78 Effects on nutrient enrichment on blue-green algae 31

References 248: 117- 1 27. Stal, L. J. & Heyer, H. 1987. Dark aerobic nitrogen fixation (acetylene reduction) in the cyanobacterium Oscillatoria sp. Ahlgren, G. 1987. Temperature fu nctions in biology and their - FEMS Microbial. Ecol. 45: 227-232. application to algal growth constants. - Oikos 49: 177-190. Thorstens on, B. In press. Nutrients. - In: Cederwall, H. (ed.) Ahlgren, G. 1988. Phosphorus as growth-regulating factor relative Dynamics of a Nodularia bloom. Swedish Environmental to other environmental factors in cultured algae. -In: Persson, Protection Agency. Report. G. & Jansson, M. ( eds.) Phosphorus in freshwater ecosystems. Uehlinger, U. 1981. Experimentelle Untersuchungen zur Aut­ Hydrobiologia 170: 191-210. okologie vonAphanizomenonflos-aquae. - Arch. Hydrobioi. Apstein, C. 1902. Das Plankton der Ostsee (Holsatia Expedition Suppl. 60: 260-288. 1901).- Abh. Deutschen Seefischerei-Vereins. VII: 103- Wa11strom, K. 1988. The occurrence of Aphanizomenon flos­ 129. aquae (Cyanophyceae) in a nutrient gradient in the Baltic. ­ Borysiak, M. & Ringer, Z. 1982. Composition and biomass distri­ Kiel. Meeresforsch. Sonderh. 6: 210-220. bution of phytoplankton in the southern Baltic in July 1981.­ Wallstrorn, K. 1991. Ecological studies on nitrogen fixing blue­ ICES C.M. 1982/ L:6l. 16pp. green algae and on nutrient limitation of phytoplankton in the Edler, L. (ed.) 1979. Recommendations on Methods for marine Baltic Sea. - Compr. Summ. Uppsala Di s. Fac. Sci. 337. biological studies in the Baltic Sea. Phytoplankton and chloro­ 23pp. phyll. - Baltic Mar. Bioi. Publ. 5: 1-38. Wallstrom, K. In press. Phytoplankton composition and biomass Edler, L., Ferno, S., Lind, M. G., Lundberg, R. & Nilsson, P. 0. during a Nodularia bloom in the Baltic 1982. - In: Cederwall, 1985. Mortality of dogs a ociated with a bloom of the H. (ed.) Dynamics of a Nodularia bloom. Swedish Environ­ Nodularia spumigena cyanobacterium in the Baltic Sea. - mental Protection Agency. Report. Ophelia 24: 103- 109. Wiktor, K. & Plinski, M. 1975. Changes in plankton resulting from Elmgren, R. 1989. Man's impact on the ecosystem of the Baltic the eutrophication of a Baltic firth. - Merentutkimuslait. Sea: energy flows today and at the turn of the century. - Julk./ Havsforskningsinst. Skr. 239: 311-315. Ambio 18: 326-332. Graneli, E., Wallstrom, K., Larsson, U., Graneli, W. & Elmgren, R. 1990. Nutrient limitation of primary production in the Baltic Sea area. - Ambio 19: 142-151. Grasshoff, K., Ehrhardt, M. & Krem1ing, K. 1983. Methods of eawater analysis. -Verlag Chemie GmbH, Weinheirn.419 pp. Hiibel, H. & HUbel, M. 1980. Nitrogen fixation during blooms of Nodularia in coastal waters and backwaters of the Arkona Sea (Baltic Sea) in 1974. -Int. Revue Ges. Hydrobiol. 65: 793- 808. I tvanovics, V., Voros, L., Herodec, S., Toth, L. G. & Tatrai, I. 1986. Changes ofphosphorus and nitrogen concentration and of phytoplankton in enriched lake enclo ures. - Limnol. Oceanogr. 31: 798-81 1. Kaiser, W., Schulz, S.& Kell, V. 1981. Die Wirkung der Pollution auf das Phytoplankton und seine Prirnarproduktion. - Geod. Geoph. VerOff. R. IV H. 33: 53-60. Larsson, U. & Hagstrom, A. 1982. Fractionated phytoplankton primary production, exudate relea e and bacterial production in a eutrophication gradient. - Mar. Bioi. 67: 57-70. Lindahl, G., Wallstrom, K. & Brattberg, G. 1978. On nitrogen fixation in a coastal area of the northern Baltic. - Kiel. Meeresforsch. Sonderh. 4: 171-177. Me1vasalo, T. & Viljarnaa,H. 1977. Planktonic blue-green algae in polluted coastal waters off Helsinki. - Publ. Wat. Res. Inst. 19, Helsinki. 35 pp. Nierni,A. l976. Blomning av blagronalger i bstersjon. -Norden­ skiold-samfundets Tidskr. 36: 14-25. Nordling, C. (ed.) 1984. Analysresultat fran "Naringsamnes­ undersokningen i Stockholrns skargard 1969- 1 976". - Swe­ dish Environmental Protection Agency. Report 1854. 77 pp. Riddolls, A. 1985. Aspects of nitrogen fixation in Lough Neagh. II. betweenAphanizomenonlos-aquae, Oscillatoria Competition f redekei and Oscillatoria agardhii. - Fre hw. Bioi. 15: 299- 306. Rinne, 1., Melvasalo, T., Nierni,A. & NiemistO, L. 1981. Studies on nitrogen fixation in the Gulf of Bothnia. - Finn. Mar. Res.

Acta Phytogeogr. Suec. 78

Studies on the Fucus vesiculosus community in the Baltic Sea

Hans Kautsky1, Lena Kautsky2, Nils Kautsky1, Ulrik Kautsky1• 3 & Cecilia Lindblad1• 3

Abstract Kaut ky, H. et al. 1992. Studies on the Fucus vesiculosus community in the Baltic Sea-Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-721 0-078-8.

Fucus vesiculosus L. is a keystone species in the Baltic Sea forming the basis of its most species-rich biotope with great importance for the structure and function of the coastal zone and probably for the total Baltic Sea. F. vesiculosus in the Baltic lives close to its tolerance limit of salinity, and it is threatened by pollution, both locally in industrial outlet areas, as well as by continued large-scale accumulation oftoxic substances, orby a general eutrophication of the Baltic Sea. Environmental conditions, such as salinity and wave exposure, affect growth and reproduction of F. vesiculosus and cause shifts in the community composition. Local and regional eutrophication of the Baltic Sea reduces the depth distribution of the phytobenthic community. Toxic substances may inhibit growth and reproduction of both plants and animals of the Fucus community. Enclosure experiments demonstrate the sensitivity of F. vesiculosus to tributyltin (TBT) and chlorate recorded by its changed metabolism. Structural changes of the phytobenthos have been observed outside pulp mills along the Swedish Baltic coast, and their effluents seem to have regional effects on the distribution of F. vesiculosus in the Bothnian Sea. An example of the energy flow in the F. vesiculosus community is given. As there is no other large, architectural1y complex alga penetrating into the Baltic Sea, the disappearance of F. vesiculosus over larger areas would have profound effects on the ecology and productivity of the coastal area of the Baltic Sea, as well as on fish production and human recreation.

Keywords: Energy flow; Macroalgae; Phytobenthos; Pollution; Primary production; Pulp mill; Reproduction; Tributyltin.

1 Department of Systems Ecology, Stockholm University, S-106 91 Stockholm, Sweden; 2 Department of Botany, Stockholm University, S- 106 91 Stockholm, Sweden; 3 Department of Zoology, Stockholm University, S-106 91 Stockholm, Sweden.

Introduction competition from other large algae and impact of several environmental factors such as ice-scouring during winter Much of the earlier knowledge about the ecology and distri­ and long periods of low water levels in spring (e.g. Levring bution of the marine brown alga Fucus vesiculosus L. 1940, Wrem19 52, 1 965, von Wachenfeldt 1975, Wallentinus (bladder-wrack) in the Baltic Sea dates back to the pioneer­ 1976, 1979, 1991, H. Kautsky 1988, 1989). As there is no ing diving work of Wrern(1 952, 1965). F. vesiculosus can pronounced interspecific competition for space with other be found forming belts down to about 4 %o S in the northern large algae, it can extend its depth distribution from about Quark (Pekkari 1973) (Fig. 1). It is the only large, structur­ 0.3-0.5 m to at least 5-7 m depth in the coastal areas of the ally important alga found in the Baltic Sea, except in the Baltic Sea. In offshore clear waters it reaches depths down southern partof the Baltic Sea proper, where Fucus serratus to about 10-12 m, while in areas with turbid water its depth L. also can form belts, often together with F. vesiculosus in distribution is reduced or it disappears completely. Strong mixed stands. F. vesiculosus constitutes the basis for one of water movements prevent F. vesiculosus from establishing the most important communities in the Baltic Sea. While in at wave-exposed sites. the North Sea F. vesiculosus is restricted to the intertidal, it One exception to the normal sublittoral distribution is grows submerged in the Baltic Sea, because of lack of found along the ferry routes, where Fucus vesiculosus grows

Acta Phytogeogr. Suec. 78 34 H. Kautsky et al.

Northern limit of belt-forming ?ucus Yesicu/osus

FINLAND

SWEDEN J

Investigated, described in this text

• Phytobenthic sludies by the authors

Fig. 1. The Baltic Sea and the Swedi h west coast with areas inve tigated marked and named when referred to in the text.

on rocks at 0.5 m above the water surface. This has been places and feeding ground for mobile invertebrates and fish. observed both along the Finnish and Swedish coast There i no other large alga to replace it in case of its (Ronnberg 1981, Ronnberg et al. 1992, H. Kautsky unpub­ disappearance (N. Kautsky et al. 1986). lished). Elsewhere in the Baltic Sea, due to the lack of tides, Thus, studies of the structure and function of the Baltic this growth habitat is unknown, whereas along these routes Fucus vesiculosus ecosystem are of great importance for the rocks are wave-swept several times a day by the frequent understanding and evaluating biological processes in the and regular ferry traffic, enabling F. vesiculosus to grow Baltic coastal zone. In the present paper we review the above the water surface until scraped off by the ice. autecology and morphology of F. vesiculosus. We also On shallow hard substrMa, even on single stones sur­ discuss the distribution, productivity, metabolism and en­ rounded by soft sediments, the Fucus vesiculosus commu­ ergy flows of the Fucus community in the Baltic Sea under nity is the dominant biotic element over large parts of the normal conditions and under stress from pollution. We Baltic Sea. In an open archipelago area at Asko, the northern devote special attention to studies that have been carried out Baltic Sea proper (Fig. 1), it constituted 33 % of the total at Stockholm University. plant biomass (Jansson & Kautsky 1977). With ea. 30 species of associated macrofauna and macroscopic epiflora, this is the most diverse community in the relatively species­ poor brackish Baltic Sea (e.g. Segerstrale 1944, Haage Autecology of Fucus vesiculosus 1975, 1976, H. Kautsky 1989, L. Kautsky & H. Kautsky 1 989). This productive belt also constitutes spawning, breed­ ing and foraging areas for commercially important fish (e.g. Morphological variation Aneer 1985). The reason for the comparatively high species diversity is probably the perennial nature of the Fucus belt, In the Bothnian Sea, F. vesiculosus occurs in two morphs which forms plenty of niches for epiphytes, sessile filter (Wrern 1952), one with a broader thallus, dominating in the feeders, grazers and browsers as well as shelter, hiding Baltic Sea proper, and one smaller, narrow, richly branched

Acta Phytogeogr. Suec. 78 Th e Fucus vesiculosus community in the Baltic Sea 35

30 30 30

ASKO EXPOSED � ASKO SHELTERED ASKO MEDIUM EXPOSED > 0 z w :::> 0 w a: u. 10 10

10 40 80 10 40 80

LENGTH INTERVAL (CM)

Fig. 2. Length di tribution of three Fucus vesiculosus populations at Asko, northern Baltic Sea proper, July 1989 (sheltered, medium exposed, exposed to waves).

form. These are growing side by side in the Aland Sea and 27.8 g dry weight ind-1 ) in spite of the fact that the individu­ also along the Estonian coast (L. Kautsky unpublished). The als in the smallest size class (0- 1 0 cm) were not collected at narrow form increases further north in the Bothnian Sea Monsteras. At the two sheltered sites in the pollution gradi­ (e.g. H. Kautsky 1989). As described earlier (e.g. Wrern ent at Monsteras the mean value of the individuals at 1952) F. vesiculosus individuals may also locally become Vargeskar was largest ( 42.9 g dry weight ind-1 ) closest to bushier with increasing exposure (see also Kalvas 1989 and the outlet, intermediate at Soleskar (32.3 g dry weight ind-1 ) literature cited therein). and significantly smaller at Melgrundet (9.8 g dry weight 1 There are few studies where the morphological character­ ind- ) (P < 0.001), furthest away from the outlet. As antici­ istics and the life cycle of the Baltic populations of algal pated the number of air vesicles and thallu breadth de­ species have been compared with marine areas. Russell creased with increasing exposure and the thallus breadth ( 1 985a) compared the morphology ofa F. vesiculasus popu­ was significantly less in the Monsteras populations com­ lation from the Baltic Sea (Finnish coast) with a population pared to the Asko populations. from the English coast. Other examples cover Chorda filum The percentage of partly-destroyed receptacles was gen­ (L.) Stackh. (Russell 1985b) and Phycodrys rubens (L.) erally only a few percent in the populations studied, except Batt. (Rietema 1991). However, contrary to many other red in the population at Melgrundet, where almost 30 % of the and brown algal species, the outer morphology and size in receptacles showed signs of grazing. However, only a few F. vesiculosus is not affected by the lower salinity in the percent of the vegetative tips were damaged, except at Baltic Sea (Russell 1985a). V argeskar, closest to the pulp mill, where 9 % of the tips We have compared the size and age structure of Fucus were partly destroyed. Moss ( 1966) and Fulcher & McCully vesiculosus populations from a wave exposure gradient at (197 1) have shown that several Fucus species after being Asko (Kalvas 1989, L. Kautsky & A. Kalvas unpublished) grazed or having thallus tips torn away, dichotornize and and those in a pulp mill effluent area at Monsteras (Fig. 1). become more branched. Varying grazing pressure between The size distribution along an exposure gradient at Asko sites could therefore give rise to phenotypic differences showed that heavy and larger individuals, i.e. tufts united between populations, resembling those found in the Asko with a holdfast, predominated at the sheltered site and that and Monsteras populations. shorter individuals dominated at the exposed sites (Fig. 2). A similar pattern was also found at the slightly exposed reference site Melgrundet, in the Monsteras area, where, Fucus reproduction however, only plants larger than 10 cm were collected. At sites closer to the paper mill, Soleskar (sheltered) and Deviations in sex ratio from 1 : 1 in Fucus vesiculosus have especially at V argeskar (sheltered), the populations were been assumed to be due to the different environmental dominated by specimens 35-40 cm tall (Fig. 3) and only few demands of the sexes or to different sensitivity to disturb­ smaller and larger individuals were recorded. ance (Vernet& Harper 1980). In the Asko area more male The average length and weight was larger in F. vesiculosus than female individuals were found giving a sex ratio of 1 : from the Asko area (45.8 cm, 45.9 g dry weight ind-1 , 0.87 (Kalvas 1989). Statistically, this was not significantly respectively) compared to the Monsteras area (35.3 cm, different from 1 : 1. At the northern distribution limit of

Acta Phytogeogr. Suec. 78 36 H. Kautsky et al.

MELGRUNDET SOLESKAR VARGESKAR 30 30 30

';!. > 0 z w :::J 0 w a: u.1

80 80

LENGTH INTERVAL (CM)

Fig. 3. Length distribution of three Fucus vesiculas us populations in a pulp mill effluent gradient at Monstedts, Baltic Sea proper, July 1989. Vargeskar and Soleskar are close to the outlet and sheltered and Melgrund is the slightly more exposed reference station. x = not sampled.

F. vesiculosus the main part of the population is not fertile in Finnish studies was detected in mid-October after the and of the few reproductive individuals found, all were plants had been exposed to shmt-day stimulus for two females (Stefan Falk pers. comm.). Male gametes are sub­ weeks (Back et al. 1991) and remained dormant over winter ject to a greater change in volume than female ones by until the ice-melt in April. Differences in the formation of osmotic stress, since they have a larger surface to volume receptacles have been reported between populations from ratio. Such decreases in volume due to low salinity could the Finnish coast (Tvarminne), which had mature oogonia affect the spatial arrangement of the surface receptors in­ from 6-20 June and populations from Hilbre, England, volved in gamete recognition and fertilization (Wright & where these already occurred at the end of March (Russell Reed 1990). This means that male gametes would determine 1985a). Differences in day length and temperature were the salinity tolerance of germination, which concurs with suggested as possible explanations for the time differences results from the archipelago of Stockholm (Andersson et al. in receptacle formation and maturation of oogonia (Russell in press). 1985a). The mean size of Fucus vesiculosus plants at first repro­ No fertilization occurred at temperatures above 15-16 oc duction was about 25 cm in the Asko population. Thus, with in laboratory experiments with plants from the northern a growth rate of 10-15 cm per year the individual plants Baltic Sea proper, despite the presence of free, and as far as would become reproductive in their second or third growth could be noticed, vital eggs up to 20 oc (Andersson et al. in season (L. Kautsky unpublished). press). This is in contrast to Fucus populations from inter­ Most fucoids exhibit one seasonal reproduction period tidal areas, which were fertilized at temperatures of 0-20 oc with receptacles initiated at the beginning of the year or in (McLachlan et al. 1971). In our experiments an optimum late autumn of the preceding year. They normally mature was found at 10 %o S, which shows some adaptation to during spring and early summer, but differences in repro­ lowered salinity, but also that the normal salinity of 6 %o at ductive patternshave been observed between fucoids (Knight Asko still, to some extent, inhibits germination (Andersson & Parke 1950). Wrern(19 52) stated that the receptacles are et al. in press). formed in January in the Baltic populations and Miiller­ Stoll & Kiinzenbach (1956) observed inititation of new Reproductive effort and allocation receptacles in deep water forms of F. vesiculosus at Hiddensee in July, but only in a few individuals. Carlson Receptacles are photosynthetic during their entire growth, ( 1 990) reported a second reproduction period in late autumn contrary to flowering plants, which have higher reproduc­ in the Oresund, with smaller receptacles than those initiated tive costs since their reproductive parts are largely non­ during spring. Wallentinus (1979) reported that "the recep­ photosynthesizing. However, for Fucus vesiculosus there is tacles of the following spring can often be traced already a trade-off between producing receptacles or new vegeta­ during winter" but she did not give any specific time of tive tips on the dichotomies. Thus, the relative proportion of initiation. At Asko the earliest stages of receptacle initiation receptacles compared with the total number of tips would be were observed in rnid-October and they never matured that an estimate of the reproductive costs of the algal individuals autumn. Similarly, the earliest stages of receptacle initiation (Back et al. 1991, L. Kautsky & A. Kalvas unpublished). In

Acta Phytogeogr. Suec. 78 The Fucus vesiculosus community in the Baltic Sea 37

the Asko area the relative abundance of receptacles de­ Structural changes within the Baltic creased with increasing exposure, which is interpreted as being due to disturbance resulting in less energy spent for phytobenthos caused by disturbance of reproduction (Kalvas 1989). Cousens (1986) found the Fucus vesiculosus same for Ascophyllum nodosum (L.) Le Jol. whose repro­ ductive effort decreased at extremely high exposure. On the contrary, Back et al. (1991) found no significant difference During the last decade several reports about the decline and in reproductive phenology or in fecundity indices between change in the Fucus vesiculosus vegetation in the Baltic exposed and sheltered populations at the Finnish coast. So Sea have been presented. From Finland, Kangas et al. far, no correct calculations of reproductive efforts in ( 1982) and Hallfors et al. ( 1984) reported changes from the south coast and Ronnberg et al. (1985) from the Aland Sea. F. vesiculosus have been published since the reproductive efforts should be analysed at the individual level and not for In the sound of Kalmar at the Swedish east coast, Lindvall populations (Aberg 1990). Difficulties are also obvious in ( 1984) observed a decline in F. vesicu losus due to effects of comparing the energy cost in producing reproductive and pulp mill effluents and H. Kautsky (1989, in pres a, b) vegetative tissue since both are photosynthetically active. described similar effects from several areas (see also be­ Reproductive allocation is commonly determined from low). In the southwestern Baltic a drastic decline has been biomass partitioned in receptacles and vegetative fronds described, explained by increasing eutrophication of the (Cousens 1986). In the pollution gradient at Monsteras the Kiel Bight, but also as an effect of stone fishing, reducing amount of reproductive tissue, e.g. percent biomass (g dry the suitable substrate (Breuer & Schramm 1988, Vogt & weight) allocated to receptacles, was significantly larger for Schrarnm 1991). Most papers are dealing with the structural individuals close to the outlet at Vargeskar (15.4 %) and changes of the communities. Usually, observations have been made when vesiculosus already has disappeared or Soleskar (16.6 %) (P < 0.001) compared to Melgrundet F. (10.7 %). Similarly, reproductive biomass allocated to ripe changed its distribution (N. Kautsky et al. 1986, H. Kautsky 1991). Before such changes in community structure occur, receptacle biomass (g dry weight) was significantly (P < 0.001) larger for individuals from Vargeskar and Soleskar a period of reduced functional efficiency in the community compared to individuals from the Asko area (16.2 % and may have occurred. There have been several reviews on 11.2 %, respectively) for individuals larger than 25 cm. changes in the Baltic phytobenthic communities due to Furthermore, the receptacles of the Asko populations eutrophication and pollution (e.g. Wallentinus 1981, 1983, 1991, H. Kautsky 1991). were significantly heavier (P < 0.001), with a mean of 25.2 mg dry weight per receptacle, than those of the Monsteras area (mean 12.5 mg dry weight per receptacle). Russell ( 1979) has shown that estuarine Fucus vesiculosus popula­ Revisit to Mats Wrern's diving sites around Graso and tions have significantly larger and heavier receptacles than Singo, the Aland Sea genuine marine populations, and Back et al. (199 1) ob­ served large differences in plant size, receptacle morphol­ Mats Wrern was a pioneering diving phycologist in his ogy and reproductive allocation between an exposed and a studies (Wrern 1952) in 1943-44 around the islands ofGraso A sheltered F. vesiculosus population at the Finnish coast, and Singo in the land Sea (Fig. 1 ). Most of his diving sites with the highest reproduction at the exposed site. were revisited under his guidance in 1 984 (N. Kautsky et al. Knight & Parke ( 1 950) showed for both Fucus vesiculosus 1 986) and the results were based on direct comparisons with and F. serratus that the whole branch is gradually aborted the historical data. Mats Wrern's participation during this during late summer if all thallus tips on a branch have study, his excellent recognition of the sites and of species receptacles. This means that larger individuals with a large distribution in the area simplified the field work immense! y. number of receptacles lose a greater proportion of their Also, comparisons of the appearance of the plants were thallus tips, e.g. in the most sheltered A ko populations and possible thanks to his large herbarium collection from the at V argeskar where a large proportion of the thallus tips 1940s. This emphasizes the importance of collecting herba­ (37 .1 %) were reproductive. This contributes further to less rium specimens not only for taxonomic but also for ecologi­ bushy individuals. Still, even if the total biomass used for cal purposes. reproduction by a single thallus was larger at the location During the 40 years between 1944 and 1984 the Fucus closest to the outlet, i.e. at Vargeskar, no individuals were belt had decreased its depth distribution at all sites, on found in the population in the size classes between 10-25 cm average by 3 m, from a maximum depth of 11 m to 8.5 m, (Fig. 3) which suggests a hampered establishment of new and it had a maximum cover at 3-4 m instead of 5-6 m (N. individuals. Kautsky et al. 1 986). The deepest-growing plants also showed about the same dark and suppressed growth forms in both studies, while the more luxuriant ones from 8.5 m in the 1940s were similar to the more shallow plants in the 1980s. In 1984, the divers also observed a shift in the algal belts

Acta Phytogeogr. Suec. 78 38 H. Kautsky et al.

inner archip. intermediate archipelago outer archipelago

Furholmen Jutskar Isskaren Lacka %

+

D Year 1974

• Year 1988, 1990

Fig. 4. Revisit to phytobenthic localities in the Asko archipelago. Depth distribution and degree of cover (%) of Fucus vesiculas us in 1 974-

1975 and in 1988 or 1990. + indicates that single plants were observed.

below F. vesiculosus, from a dominance of Sphacelaria area, the northern Baltic Sea proper (Jansson & N. Kautsky arctica Harv. to belts dominated by red algae such as 1977, H. Kautsky 1989, H. Kautsky & van der Maarel Ceramium tenuicorne(K iitz.) Wremand Rhodomela confer­ 1990). voides (Huds.) Silva. All these changes caused major Some of these stations were revisited during August 1989 concern. and 1990 (Figs. 4-7). Observations of depth distribution and The observed decrease in depth of Fucus vesiculas us was degree of cover showed that Fucus vesiculosus had dis­ considered as most probably due to reduction of light pen­ appeared almost completely from localities close to the etration in the water (N. Kautsky et al. 1986). Later, this was mainland (Furholmen). In the intermediate archipelago ar­ supported by published data on reduced mean Secchi disk eas (Bjorkholmen, N Jutskar and Jutskar) the Fucus com­ depth readings of about 3 m (from 9.3 m to 6.5 m) during the munity had decreased in cover, while in the outer archi­ period from 1914-39 to 1969-86 (Launiainen et al. 1989). pelago areas (Isskaren and Lacka), no major change was The decreased light availability was in turn suggested to be observed. caused by regional, large scale eutrophication of the north­ Quantitative biomass data from the same area were col­ ern Baltic Sea proper, increasing the pelagic primary pro­ lected in 1990. The locality at Furholmen, close to the duction and hence turbidity. This can be argued also on mainland, showed the most dramatic changes (Fig. 5). basis of estimated increases in nutrient concentrations dur­ Maximum plant biomass was reduced from about 370 g to ing the last century, with a fourfold increase for nitrogen and about 30 g dry weight m-2. The Fucus vesiculosus belt had eightfold for phosphorus (e.g. Larsson et al. 1985). disappeared, and other algae had reduced their biomass to approximately one third. Instead, the blue mussel (Mytilus Temporal changes in the Asko area edulis L.) had increased at all depths. In 1 990 the detriti vorous snails Hydrobia spp. dominated the snail biomass, having Except for the studies by Wrern, historical quantitative replaced the grazing snail Th eodoxus fluviatilis (L.), which phytobenthos data from the Swedish coast of the Baltic Sea was dominant in 1974. At N Jutskar, located in the shel­ older than the mid-1 970s are lacking. In 1974 and 1975 an tered, intermediate archipelago, F. vesiculosus still formed extensive quantitative investigation was performed cover­ belts in 1 990, but biomass per unit area was reduced (Fig. 6). ing phytobenthic plant and animal communities in the Asko Also the other algae had less biomass in 1990 compared to

Acta Phytogeogr. Suec. 78 The Fucus vesiculosus community in the Baltic Sea 39

PLANTS ANI M LS - Blucgrcen small groups F M � 870 CJ Green snails Brown mussel!'. 5 CJ (F=Fucus) (M=Mytilu")

Red I nsect s

Phanerogams Crustacea a b Furholmen 1974 Others Others 10

100

M 5 E -5 0... Cl.) -o

10

c d Furho1men 1990

Fig. 5. Depth distribution of plant (a, c) and animal (b, d) biomass in 1974 and 1990 at Furholrnen, Asko area.

that in 1974. The blue mussel had increased at all stations Swedish coast, from around Asko down to the sound of except at Isskaren, in the outer part of the archipelago, Kalmar, with F. vesiculosus di appearing from the shel­ where apart from a few extreme values, the blue mu sel had tered parts close to the mainland, being replaced by commu­ about the same biomass in 1990 a in 1974 (Fig. 7). nities dominated by Ceramium tenuicorne and Mytilus edulis. F. vesiculosus had reduced it biomass from about 750 g to Thu , around the Swedish coast of the Baltic Sea proper it 50 g dry weight m-2, although the estimates of the cover seems that the inner parts of the archipelagos are the first to degree of F. vesiculosus indicated somewhat less dramatic lose the Fucus community. This indicates the importance of changes (Fig. 4). land-based pollution sources for the observed changes in the The same pattern of reduction of Fucus vesiculosus has archipelagos. been observed in various archipelago areas along the The changes in the Asko area showed imilar dramatic

Plants Animals 0 250 0 500 LOO lOO g dryweight m-2

E ..s:: a Cl.) -o 5 b N Jutskar 1974

1 964 E ..s:: M 0.. Fig. 6. Depth distribution of plant (a, c) Cl.) -o and animal (b, d) biomass in 1974 and 5 1 990 at N Jutskar, Asko area. For legend, c d see Fig. 5. N Jutskar 1990

Acta Phytogeogr. Suec. 78 40 H. Kautsky et al.

F

b Isskaren 1974

5 5

10 10

E -s fr -o

15

Isskaren 1990

Fig. 7. Depth distribution of plant (a, c) and animal (b, d) biornass in 1974 and 1990 at Isskaren, Asko area. For legend, see Fig. 5.

1 5 10 15 Distance km 0 A

s 5 -5 Scale%oo 0.. ll) 50 0 10 25 Iggesu lcl T+

Fig. 8. Depth distribution of the B phytobenthic community in the Ig­ gesund and Monsten1s areas. In the Iggesund area, the depth range of Fucus vesiculosus is indicated by a darker shading. At Monsterfts (in 5 vertical bars) the type of substrate is s indicated (hatched = boulders and stones, dotted = sand). The bars also show the depth distribution of the phytobenthic community. In addi­ tion, the depth distribution and cover Monsteras degree (%) of Fucus vesiculas us and 10 F. serratus are indicated.

Acta Phytogeogr. Suec. 78 The Fucus vesiculosus communityin the Baltic Sea 41

lggesund Norrsundet Monsteras

Hudiksvall

Cover degree EB25 % of Fucus vesiculosus 50 %

0 km 5 Okrn 2 L____J '---'---1

Fig. 9. Maximum cover of Fucus vesiculosus in the receiving areas of pulp mill effluent at Iggesund, Norrsundet and M on teras. (Note the diffe rent cales.)

changes of the phytobenthic communities as observed in In the receiving areas close to the point of discharge, off other parts of the Baltic Sea. For instance, in the Archi­ Iggesund, Norrsundet and Monstedis (Fig. 1), it is not pelago Sea, Finland, Fucus vesiculosus di appeared from possible to distinguish whether the effects on the plant and vast areas of the middle part of the archipelago in the end of animals were due to toxic substances, water-colouring and the 1970s (e.g. Kangas et al. 1982, Ronnberg et al. 1985, turbidity, or eutrophication by nutrients and organic matter Hallfors et al. 1987) and the Fucus community was replaced in the effluents. However, the light penetration in the water by filamentou and loo e-lying algae. Kanga et al. (1982) column was almost negligible close to the source, e. pecially gave a general description of the events. They pointed to off Igge und and Norrsundet. The pulp mill at Monsteras several factors including the importance of epiphytic growth discharges its effluents through a diffusor. Thus, as efflu­ and herbivore grazing [mainly ldothea baltica (Pallas)] in ents are diluted and discharged into well ventilated, larger the final stage ofdi appearance ofthe b 1 adder-wrack. Hallfors areas, the turbidity in the receiving area there is less than off et al. ( 1987) suggested that the disappearance was due to the other pulp mills. The plant community off all mills was eutrophication caused by upwelling of nutrient-rich bottom restricted to the surface close to the source of effluent , and water. During the late 1980 , recovery of the Fucus belt has was found down to 10-15 m depth only at longer distances been observed, but until now only the substrate close to the from the discharge, the normal for non-polluted areas of the water surface has been colonized (Kangas & Niemi 1985, Baltic Sea (Fig. 8). Ronnberg et al. 1985, Olof Ronnberg pers. comm.). Fucus vesiculosus was missing close to the source of effluents at both Iggesund, Norrsundet and Monstedts (Fig. Phytobenthic communities in pollution gradients 9). Instead, the plant biomass was dominated by opportun­ i tic, annual algae, benefiting from high nutrient contents in In the Baltic Sea, close to the source of effluents from pulp the water. The nutrients are discharged directly, but they are mills, phytobenthic communities show significant changes probably also recycled by the dominating filter feeders, in both extension, species number and species composition using the discharged organic matter as food. as well as biomass (Lindvall 1984, H. Kautsky 1989, in In the intermediate receiving areas the effects from col­ press a, b, H. Kautsky et al. 1988, H. Kautsky & Foberg ouring, turbidity and high nutrient concentrations had de­ 1990, 1991). The changes can be due to turbidity, eutro­ creased. Species composition was almost the same as at the phication and toxic substances. These factors may act to­ reference stations, and Fucus vesiculosus was found down gether or separately, and are not always possible to distin­ to about 5-7 m depth, but it covered only small patches. guish. Furthermore, differences such as type of substratum, Thus, the effects on the horizontal distribution of F. vesi­ wave exposure and salinity, may influence species distribu­ culosus partly remained (Fig. 9). This indicates that toxic tion and biomass. The plants usually showed the most substances from the pulp mills still influenced the Fucus significant changes in receiving areas. community. Some epiphytic brown algae on F. vesiculosus

Acta Phytogeogr. Suec. 78 42 H. Kautsky et al.

were missing close to the effluent discharge and also in the Effiuentsfrom puiJ>mills

Fucus vesiculosus intetmediate area at Monsteras (H. Kautsky & Foberg 1991 ). Suspended maller (SM) A reduction of chlorate in the effluents of Monstedis has 0 Chemical oxygen demand (COD) Fucus by resulted in partial recovery of the distribution of vesi­ 0 Biological oxygen demand (BOD) F. culosus in the receiving area (H. Kautsky & Foberg 1991). • TOCI In the outer part of these archipelagos, the water exchange is considerable and the effluents much diluted. There, luxu­ rious Fucus vesiculosus belts occurred again, and other plants and animals showed a normal distribution pattern (e.g. H. Kautsky 1989). The influence from industries on the regional distribution of the Fucus vesiculosus community is indicated in Fig. 10. The figure shows the distribution of F. vesiculosus along the coast of the Bothnian Sea as surveyed by divers in 1988 (H. Kautsky 1989). At its northern limit, in the northern Quark, F. vesiculosus occurred abundantly, having a cover degree of the substratum of up to 75 %. Southwards, F. vesiculosus disappeared outside the pulp mill of Husum, and occurred again in a reduced growth form further south, at Skags Udde. At the less polluted Hoga Kusten (High Coast) area F. vesiculosus was commonly growing, while in the bay of Sundsvall it was missing, probably due to the large fresh water outflow from the river Indalsalven. Several industries are also located in this area. South of Sundsvall, down to the Hornslandet area Uust north and off Iggesund), vesi­ 1:)- --- t------,11 10 SM. COD. BOO SO F. culosus was abundantly found, both washed ashore, and 106 kg year-! observed by divers. This part of the coast receives almost no industrial discharges. On the landward side of Hornslandet, Fig. I 0. Maximum cover of Fucus vesiculosus along the coast of in the receiving area of the pulp mill at Iggesund, the Gulf of Bothnia. Observations are ba ed on diving transects and F. vesiculosus grew poorly and was missing in vast areas. wrack fo und wa hed ashore. The effl uents from various pulp mills Between the Iggesund area and the Bay ofGavle (bordering along the coa t are indicated by the load of suspended matter, the Aland Sea), vesiculosus occurred infrequently. This chemical and biological oxygen demand, as well as total organic F. chlorinated matter(TOCI). The absence of F. vesiculosus is indicated part of the coa t has several pulp mills. Not until as far south A F. vesi- by # if not observed by divers, or n if not found on the shore. as in the Graso-Singo area (the land Sea) were

J Plants Animals Trophic grOUJli

s Fiheneeders - Bluegreen Small group c:::J oreen Snails Grazers

Fucus Mussels C o s c:::JBrown + arniv re vesiculosus Crustaceans Derritivores D F. c::::J Red Insects Omnivores

e s Phan rogam

Fig. 11. Distribution of plants and animals in the receiving areas of effluents from pulp mills outside Iggesund, Norrsundet and Monsteras. The number of species (A), biomass of plants (B), percent composition of plants (C), biomass of animals (D), and percent composition of animals (E), and animal functional groups (F) are indicated. B= Bryophytes, C=Charophytes.

Acta Phytogeogr. Suec. 78 The Fucus vesiculosus communityin the Baltic Sea 43

culosus belts luxurious, covering 100%of the substratum. long life pan F. vesiculosus is useful as a bio-indicator, for Thus, the abundance of F. vesiculosus seems to be nega­ example for heavy metals (e.g. Forsberg et al. 1 988, Ronnberg tively correlated to the occurrence of industrial discharges et al. 1990, 1992) and radionuclides (e.g. Carlson & mainly from pulp mills (Fig. 10). Erlandsson 1991), as it integrates the exposure over a long In the pollution gradient off the pulp mills of Iggesund, time period. Norrsundet and M on teras, the benthic communities showed Odum (1985) discussed general effects of perturbations simi lar trends in number of taxa found, specie composi­ on the ecosystem level uch as responses in energetics tion, functional group and biomass (Fig. 11), although (community production and re piration) and other func­ locally different species dominated, depending on the type tional properties. Those respon e have been tested mainly of substrate in the area. The most polluted areas had high by using microcosms with periphyton, (e.g. Scanferlato & abundances of a few plant and animal species. Opportunis­ Cairns 1990) or whole-lake experiments (e.g. Schindler tic, annual species with high nutrient uptake capacity (fa­ 1990). However, microcosm experiments are often le voured by high nutrient load) dominated among the plants. realistic and difficult to interpret due to laboratory effects. The animals were totally dominated by fi lter feeders. The The fu ll scale experiments in turn are realistic, but often lack plant biomass could al o be extremely high compared to ufficient replicates and a true control. There is also an les polluted areas. obviou risk that the importance of pecies with a short In intermediate areas, the occurrence and bioma s distri­ generation time is underestimated, since usually measure­ bution was fairly evenly distributed among several species. ments are repeated only with long intervals. The functional groups of the animals (as based on their food We have tried to fill the gap between laboratory experi­ preferences), were evenly distributed, and no group domi­ ment and whole ecosystem experiment tests by con truct­ nated. Usually, plants and animals had their highe t biomass ing a continuous flow-through system for in situ measure­ further away from the source, in the more unpolluted areas. ments of community metabolism (N. Kautsky 1984, Li ndblad Here, the highest number of species (taxa) was found, but et al. 1986, 1988, 1989). With the goal to understand the the total biomass was dominated by a few plant and animal natural variation in functional processes (metabolism) as species. The distribution of Fucus vesiculosus, in the re­ well as the deviation due to disturbance or stress, we have ceiving areas studied, indicated effects from toxic sub­ investigated functional changes of F. vesiculas us communi­ stances. F. vesiculosus responded to the toxic substances ties in situ over ten day period at several places along the not only by absence or reduced occurrence and biomass, but Swedish coast. The concentration of oxygen and nutrients also sometimes by morphological change (dwarfed growth were continuously monitored, as well as pH, temperature, of branches in den e cluster on the thallus). light, and flow rates. Uptake or release rates of nutrient As shown below, enclosure experiments of the Fucus C02 a similation, gross primary production (GP) and re pi­ vesiculosus communities also demon trate their sensitivity ration (R) rates were calculated from changes in concentration to chemicals occurring in the effluents from the pulp mills. over time. As an index of metabolic change we have used the Pertur­ bation Index (PI) that normalize differences in biomass and physiological status in the tested communities. To calculate Metabolism and functional changes in PI, each value after treatment is divided by the mean of the values before treatment and then divided by the correspond­ the Fucus vesiculosus community due to ing values of the non-treated controls (Lindblad et al. 1 986). disturbance PI is especially useful when the communities are dominated by primary producers with large diurnal variations in me­ The metabolic responses and mechanisms re ulting in the tabolism. To get a picture of the total effect of the treatment changed structure of the Fucus communities fo llowing e.g. the PI values for parameters such as PI(R) and PI(GP) are pollution have rarely been studied. Before changes in com­ plotted in a state space where the origin represents the munity structure can be observed, a period of reduced unperturbed values. The absolute distance from the origin fu nctional efficiency in the community may occur (e.g. divided by the number of parameters used, is called the Lindblad et al. 1989). This is due to the fact that the Absolute Disturbance Index (ADI) (Lindblad et al. 1988). perennial F. vesiculosus has a relatively low net production ADI integrates all PI values which makes it possible to rate up to 9 mg C (g dry weightt1 day-1 (e.g. Guterstam compare communities from different areas. 1977, 1979, Guterstam et al. 1978, Leskinen et al. 1992) and Effects on the Fucus community of antifouling paint a high individual biomass, which means that it generally containing tributyltin (TBT), (Lindblad et al. 1 989), chlorate take a long time for the Fucus communities to show visible (C. Lindblad unpublished) and changes in turbulence (C. structural changes due to changes in its environment. This Lindblad & U. Kautsky unpublished) have been studied. probably has contributed to the assumption that F. vesiculasus Results so far, showed that Fucus communities treated with has sometimes been considered as moderately tolerant to TBT at the Swedish West coast (ea. 26 %o S) were less pollution (see Wallentinus 1979 for a review). Due to its disturbed than the communities in the Baltic Sea (Asko, ea.

Acta Phytogeogr. Suec. 78 44 H. Kautsky et al.

Fucus community ADI (GP, R) P04 -P uptake after TBT treatment TBT treated Control 1 10+---�--r-�---+---+---r---+o • • TREATED 0 CONTROL � 0 TBT ...... 'o.o o.. -10 � 0 0.. -20 b.() =t.

7 Days

Gras a Asko Kampinge A ko Tjarno 5.0%o 6.3%o 8.1 %o 6.5%o 24.0%o Fig. l3. Uptake/release ofP04-Pby Fucus vesiculosuscommunities at Asko with TBT (modified from Lindblad et al. 1989).

Fig. 12. Comparison of the ab olute disturbance index (ADI) of Fucus vesiculosus communities from djffe rent alinitjes. Treated with TBT or chlorate ver us controls. Lehtinen et al. 1988). The functional changes probably will limit the distribution of F. vesiculosus and result in the structural changes reported above. Our studies al o showed 6 %o S). The results with chlorate treatment howed slightly that it i important to study the community in situ under higher ADI values for communities in the southern Baltic natural conditions to really take into account interaction Sea (Kampinge, ea. 8- 10 %o S) compared to at Asko (ea. with the surrounding environment. 6 %o S) and in the Aland Sea (ea. 5 %o S), although the differences were not large within the Baltic Sea (Fig. 12). The two substances used, chlorate and TBT, have differ­ ent effects on the Fucus communities. Low concentrations Energy dynamics and grazing of chlorate decreased the photosynthesis, while the macro­ invertebrates did not show any negative reactions. TBT had Several attempts to construct total energy budgets of the a drastic effect on both re piration and photo ynthesi of Baltic Fucus community were carried out in the 1970 (cf. Fucus, beside decreasing nutrient uptake rates (Fig . 12, Fig. 14). In the A ko area a total budget of a narrow ound 13). Negative effects on macroinvertebrate behavior were including macroalgal, oft bottom and pelagic ystems, wa also seen. TBT inhibits the ATP-synthesis in both mito­ made in early summer (Jansson & Wulff 1977). At chondria and chloroplasts (Molander 1991). In the Baltic Kampinge, southern Sweden, an energy flow model was

Sea the marine species F. vesiculosus has to allocate more constructed for a shallow F. vesiculosus community, in­ energy in maintaining the osmotic potential and therefore cluding also some other macroalgal species as well a some has les resource to withstand disturbance. This may ex­ phanerogams, rnicrophytobenthic algae and phytoplankton plain the differences in sensitivity between F. vesiculosus and their associated fauna (Jans on et al. 1982). A coar e from the Baltic Sea and from the Swedish West coast estimate on the energy flow was also made at Tvarminne in Another probable effect is that chlorate acts a an analogue the Finnish archipelago (Elmgren & Ganning 1974). Other to nitrate and is easily taken up by the algal cells, thus studies have focused on important components and path­ reducing net photosynthe is (Rosemarin et al. 1986). Low ways such as primary production and respiration during nitrate levels in the water contribute to a relatively higher different seasons (Guterstam 1977, 1979, 1981), nutrient chlorate uptake rate and increased toxicity. On the contrary, dynamics (Fig. 14: paths 21, 22; Wallentinus 1984a, 1984b, TBT gives a direct and drastic effect on the whole commu­ 1991) and release of exudates (Fig 14: path 3; Guterstam et nity related to physiological problems, while chlorate gives al. 1978). Important information for the energy budgets has slower reactions in measured parameters but also seems to also been generated from the algal zone shallower than the be much more dependent on environmental conditions such Fucus community, the Cladophora system (Jansson 1974) as ambient nitrate levels. and epilithic microphytobenthos (U. Kautsky et al. 1984, It is obvious that the Fucus communities are sensitive to Snoeijs & U. Kautsky 1989). These studies have contrib­ di turbance with a direct response in the functional para­ uted to large scale models of the Baltic Sea ecosystem (e.g. meters at low concentrations of toxic substances. The sensi­ Jansson 1984, Jansson et al. 1984). tivity of brown algae, and especially Fucus vesiculosus, to The fi ne structure within the Fucus community during mainly chlorate has also been verified through other several seasons has been described for the macrofauna mesocosm experiments (e.g. Rosemarin et al. 1986, 1990, (Haage 1975, 1976), for the meiofauna (Kangas 1978) and

Acta Phytogeogr. Suec. 78 Th e Fucus vesiculosus community in the Baltic Sea 45

from Guterstam' s ( 1981) work is that although captured with high efficiency in carbon fixation, most of the solar energy (Fig. 14: path 1) is respired by F. vesiculosus itself (30-50 %) and the consumers in the community (Fig. 14: paths 6, 8, 11, 16, 18). This means that the degree of self maintainance is low, i.e. GP/R values are around one. A large part of this respiration is due to filter feeders (5-30 %, Fig. 14: path 11) and is not fuelled by the macroalgae, but by imports from the pelagic system (Fig. 14: path 10). This creates an important food source for the rest of the bottom fauna, since the mussels, which dominate the filter feeders, produce large amounts of faeces (Fig. 14: path 12; N. Kautsky & Evans 1987). The dominant grazers/browsers in these communities are gastropods, mainly Theodoxusjluviatilis. They are not known to consume large macroalgae such as Fucus vesiculosus. Probably they feed on filamentous algae and micro-algae (Fig. 14: paths 4, 5). At Kampinge the filamentous alga Pilayella littoralis (L.) Kjellm. contributed to 30 % of the primary production (Fig. 14: path 4). This alga is avoided by Fig. 14. Energy flow model of the Baltic Sea Fucus community T.jluviatilis (U. Kautsky unpublished). At the other places during summer, compiled from Jansson & Wulff (1977), Jansson the filamentous algae contributed only little to the total et al. (1982) and Guterstam (1979). Symbols are from Odum & production during this time of the summer when Th eodoxus Odum (1976): Circles = energy source; hexagons = consumers; has its highest abundance among F. vesiculosus. The pro­ bullet shaped symbol = primary producers; 'bird house' symbol = duction by macroalgae and filamentous algae is not suffi­ storage pools. All flows (arrows) are in kJ m-2 d-1 and storages in cient to provide energy and nutrients to the grazers, if we kJ m-2. Light grey aiTows are solar energy and particulate organic assume that the consumption (Fig. 14: path 7) must be matter (POM); medium grey arrows are flows of carbon between approximately three times the respiration (Fig. 14: path 8) to compartments; dark grey aiTows represent respiration (R) which is energy lost as heat. Black arrows indicate flows of nutrients.The cover somatic growth, reproduction and excretion. Bacte­ width indicates the relative importance of the flows. Explanations rial production (Fig. 14: path 14) could be a source of energy of the different pathway : (1) The insolation at 1.2 m, where only to the gastropods, but this must be fuelled from other carbon 2% is used for gross primary production (GP); (2) F. vesiculosus sources, e.g. exudates (Fig. 14: path 3), with considerable net primary production (NP); (3) Exudate release from F. loss to respiration (Fig. 14: path 13) [20 - 50 % conversion vesiculosus; ( 4) Filamentous algae (FA) NP; (5) Benthic micro­ according to Williams ( 1 984)]. The abundance of bacteria is algae (!lA) NP; Total primary producers' respiration; (6) (7) also relatively low (Bjorkman 1987) and they cannot pro­ Herbivore food consumption estimated as three times R (H) (8); (9) duce sufficient biomass to supply the grazers, if we assume H faeces and exudates production recycled to POM; (10) Filter feeder (FF) food consumption of POM estimated from respiration one cell division per day. If the grazers would feed on faeces (11); (12) FF faeces production; (13) Bacterial (B) respiration produced by the filter feeders (Fig. 14: path 1 2), they can get ranging between 15-132 kJ m-2 d-1 ; (14) B production estimated as sufficient food supply, but this relationship is not fully 10% of respiration and 'recycled' to the pool of particulate matter investigated. While preliminary results from food selection (POM); (15) Meiofauna (M) food consumption and R (16); (17) experiments proved this, food web analysis with stable Carnivore (C) food consumption and R (18); (19) POM and isotopes did not (U. Kautsky unpublished). resuspension for filter feeders (20); (21 and 22) Recycling of It is also clear that the much discussed grazing of ldothea nitrogen and phosphorus. spp. on F. vesiculosus (e.g. Kangas et al. 1982) generally has little impact on the energy budget, due to their normally low occurrence. But when they occur very abundantly, as they did inS and SW Finland during the late 1970s, they can certainly affect both the epiphytes and F. vesiculas us itself. From all these experiments it is clear that the interactions for the spatial distribution of macrofauna and epiphytes between the Fucus community and the surrounding pelagic (F. Arrhenius & U. Kautsky unpublished). This is comple­ and land-based systems are very important, due to the filter mented by quantitative studies on the distribution and bio­ feeding activity of the mussels which supply the community mass, as well as productivity values from the functional with energy and nutrients bound in the imported organic response experiments described above. matter (Fig. 14: path 10). The Fucus community, dominated The major outcome (Fig. 14) from the two community by perennial plants, thus maintains an ongoing fixation of studies (Jansson & Wulff 1977, Jansson et al. 1982) and solar energy and nutrients throughout the year. During high

Acta Phytogeogr. Suec. 78 46 H. Kautsky et al.

levels of light and/or nutrients ephemeral micro and macro­ Forsberg, A., Soderlund, S., Frank, A., Pettersson, L.R. & Pedersen, algae further enhance the turnover capacity of the commu­ M. 1988. Studies on metal content in the brown seaweed, nity. However, when the perennial F. vesiculosus plants Fucus vesiculosus, from the archipelago of Stockholm. - disappear, there are more pronounced seasonal, oftensto­ Environ. Poll. 49: 245-263. Fulcher, R.G. & McCully, M.E. 1971. Historical studies on the chastic variations in primary production and nutrient turno­ genus Fucus. IV. Regeneration and adventive embryony. ­ ver, caused by the shorter generation time of the ephemeral Can. J. Bot. 47: 1643-1 649. algae and their greater sensitivity to grazing. Guterstam, B. 1 977. An in situ study of the primary production and metabolism of a Baltic Fucus vesiculosus L. community. - In: Keegan, B.F., Ceidigh, P.O. & Boaden, P.J.S. (eds.) Biol­ Acknowledgements. This paper is dedicated to Mats Wrern. ogy of benthk organisms. Pergamon Press, London & New All of us have been inspired by the enthusiasm of Mats W rem York. pp. 31 1-319. and his pioneering diving studies during some stage of our Guterstam, B. 1 979. /n situ -Untersuchungen i.iberSauer stoffumsatz studies. His extensive work on the algae of the Baltic Sea has und Energiefluss in Fucus-Gemeinschaften der Ostsee. - Rep. Sonderforschungsbereich 95 "Wechselwirkung Meer ­ served as a constant reference in our studies. Meeresboden", Univ. Kie1 49: 1-151. In this paper, Lena Kautsky was responsible for the part Guterstam, B. 1981. In situ investigation on the energy flow in a on the autecology of Fucus vesiculosus, Hans Kautsky for Baltic Fucus community. - In: Levring, T. (ed.) Proc. 1Oth the description of structural changes in time and induced by Int. Seaweed Symp. Goteborg, Sweden, August l l-15, 1980. pollution, and Cecilia Lindblad for metabolism and func­ Waiter de Gruyter, Berlin. pp. 405-4 10. tional changes in the Fucus community. Ulrik Kautsky Guterstam, B., Wallentinus, I. & lturriaga, R. 1978. /n situ primary compiled the part on energy dynamics. production of Fucus vesiculas us and Cladophora glomerata. - Kieler Meeresforsch. Sonderheft 3: 257-266. Haage, P. 1975. Quantitative investigations of the Baltic Fucus belt macrofauna. 2. Quantitative seasonal fluctuations. - Contr. Asko Lab. Univ. Stockholm 9: 1-88. References Haage, P. 1 976. Quantitative investigations of the Baltic Fucus belt macrofauna. 3. Seasonal variation in biomass, reproduction Aberg, P. 1990. Population ecology of Ascophyllum nodosum: and population dynamics of the dominant taxa. -Contr. Asko Demography and reproductive effort in stochastic environ­ Lab. Univ. Stockholm 10: 1-84. ments.- Ph. D. Thesis, Dept. Marine Botany, Univ.Goteborg. Hi:i.llfors, G., Kangas, P. & Niemi, A. 1984. Recent changes in the

27 pp. + 5 papers. phytal at the south coast of Finland. - Ophelia, Suppl. 3: 51- Andersson, S., Kautsky, L., Kautsky, N. In pres . Effects of salinity 59. and bromine on zygotes and embryos of Fucus vesiculosus Hi:i.llfors, G., Viitasalo, I. & Niemi, A. 1987. Macrophyte vegeta­ from the Baltic Sea. - Mar. Bioi. tion and trophic status of the Gulf of Finland - A review of Aneer, G. 1985. Some speculations about the Baltic herring ( Clupea Finnish investigations. - Meri 13: 111-158. harengus membras) in connection with the eutrophication of Jans on, A.-M. 1974. Community structure, modelling and simu­ the Baltic Sea. -Can. J. Fish. Aquat. Res. 42: 83-90. lation of the Cladophora ecosystem in the Baltic Sea. -Contr. Back, S., Collins, J.C. & Ru sell, G. 1991. Aspects of the reproduc­ Asko Lab. Univ. Stockholm 5: 1-130. tive biology of Fucus vesiculosus from the coast of SW Jansson, A.-M. & Kautsky, N. 1977. Quantitative survey of hard Finland. - Ophelia 34: 129-141. bottom communities in a Baltic archipelago. - In: Keegan, Bjorkman, K. 1987. Distribution and substrate utilisation in marine B.F., O!idigh, P.O. & Boaden, P.J.S. (eds.) Biology of benthic epiphytic bacteria from different age zones of the brown alga organi ms. Pergamon Press, London & New York. pp. 359- Fucus vesiculosus. - Dept. Zoology, Stockholm Univ. 20 pp. 366. (Mimeographed.) Jansson, A.-M., Kautsky, N., von Oertzen, J., Schramm, W., Breuer, G. & Schramm,W. 1988. Changes in macroalgal vegeta­ Sjostedt, B., von Wachenfeldt, T. & Wallentinus, I. 1982. tion of Kiel Bight (Western Baltic Sea) during the past 20 Structural and fu nctional relationships in a southern Baltic years. - Kieler Meeresforsch. Sonderh. 6: 24 1 -255. Fucus ecosystem - A joint study by the BMB Phytobenthos Carlson, L. 1990. Effects of biotic and abiotic factors on the group. - Contr. Asko Lab. Univ. Stockholm 28: 1-95 . accumulation of radionuclides in Fucus vesiculasus L. - Ph. Jansson, B.-O. 1984. Baltic Sea ecosystem analysis: Critical areas D. Thesis, Dept. Ecology: Marine Ecology, Lund Univ. 111 for future research - Limnologica (Berlin) 15: 237-252. pp. Jansson, B.-O. & Wulff, F. 1977. Ecosystem analysis of a shallow Carlson, L. & Erlandsson, B. 1991. Seasonal variation of sound in the northern Baltic - A joint study by the Asko group. radionuclides in Fucus vesiculosus L. from the Oresund, - Contr. Asko Lab. Univ. Stockholm 18: 1-160. southern Sweden. - Environ. Pollut. Bull. 73: 53-70. Jansson, B.-O., Wilmot, W. & Wulff, F. l 984. Coupling the sub­ Cousens, R. 1986. Quantitative reproduction and reproductive systems - The Baltic Sea as a case study. - In: Fasham, effort by stands of the brown alga Ascophyllum nodosum (L.) M.J.R. (ed.) Flows of energy and material in marine ecosys­ Le Jolis in south-eastern Canada. - Estuar. Coast. Shelf Sci. tems. Plenum Pub!. Corp., New York. pp. 549-595 . 22: 495-507. Kalvas, A. 1989. Ji:i.mforande studier av Fucus populationer fran Elmgren, R. & Ganning, B. 1974. Ecological studies of two 6stersjon och vi:i.stkusten. - Bot. Inst., Stockholm Univ. shallow, brackish water ecosystems. - Contr. Asko Lab. Medd. Nr. 2: 1-51. (Mimeographed.) Univ. Stockholm 6: 1-56. Kangas, P. 1978. On the quantity of meiofauna among the epi-

Acta Phytogeogr. Suec. 78 Th e Fucus vesiculas us community in the Baltic Sea 4 7

phytes of Fucus vesiculosus in the Asko area, northern Baltic Lehtinen, K.-J., Notini, M., Mattson, J. & Landner, L. 1988. Sea. - Contr. Asko Lab. Univ. Stockholm 24: 1-32. Disappearance of bladder-wrack (Fucus vesiculosus L.) in the Kangas, P. & Niemi, A. 1985. Observations of recolonization by Baltic Sea: Relation to pulp mill chlorate. - Ambio 17: 387- the bladder-wrack, Fucus vesiculosus, on the southern coast of 393. Finland. - Aqua Fenn. 15: 133- 140. Leskinen, E., Makinen, A., Forte! ius, W., Lindstrom, M. & Salemaa, Kangas, P., Autio, H., Hallfors, G., Luther, H., Niemi, A. & H. 1992. Primary production of macroalgae in relation to the Salemaa, H. 1982. A general model of the decline of Fucus spectral range and sublittoral light conditions in the Tvarminne vesiculosus at Tvarminne, south coast of Finland in 1977-8 1. archipelago, northern Baltic Sea. - Acta Phytogeogr.Suec. -Acta Bot. Fenn. 118: 1-27. 78: 85-93. Kautsky, H. 1988. Factors structuring phytobenthic communities Levring, T. 1940. Studien i.iber die Algenvegetation von Blekinge, in the Baltic Sea. - Ph. D. Thesis, Dept. Zoology, Stockholm Si.idschweden. - Dissertation, Univ. Lund. 178 pp. Univ. 29 pp.+ 5 papers. Lindblad, C., Kautsky, N. & Kautsky, U. 1986. An in situ method Kautsky, H. 1989. Quantitative distribution of plant and animal for bioassay studie of functional response of littoral commu­ communities of the phytobenthic zone in the Baltic Sea. - nitie to pollutants. - Ophelia, Suppl. 4: 159-165. Contr. Asko Lab. Univ. Stockholm 35: 1-80. Lindblad, C., Kautsky, U. & Kautsky, N. 1988. An in situ system Kaut ky, H. 1991. Influence of eutrophication on the distribution for evaluating effects of toxicant to the metabolism of littoral of phytobenthic plant and animal communities. - Int. Revue communities. - In: Cairns,J. Jr. & Pratt, J. (eds.) Functional Ges. Hydrobiol. 76: 423-432. testing of aquatic biota from estimating hazards of chemicals. Kautsky, H. In press a. The impact of pulp mill effluents on American Society for Testing and Materials, Philadelphia. pp. phytobenthic communities in the Baltic Sea. - Ambio. 97- 105. Kautsky, H. In press b. Quantitative changes of phytobenthic plant Lindblad, C., Kautsky, U., Andre, C., Kautsky, N. & Tedengren, and animal communities due to bleached pulp mill effluents in M. 1989. Functional response of Fucus vesiculosus com­ the Baltic Sea. - Swedish EPA, Symp. Saltsjobaden, 1991. munities to tributyltin measured in an in situ continuous flow­ Kaut ky, H. & Foberg, M. 1990. Skogsindu triella utslapp, paver­ through system. - Hydrobiologia 1881 1 89: 277-283. kan pa littoralsamhallet - Iggesund. - Rep. Swedish EPA, Lindvall, B. 1984. The condition of a Fucus-community in a Dept. Systems Ecology, Stockholm Univ. 37 pp. (as Swedish polluted archipelago area on the east coast of Sweden. - EPA-report, revision, mimeographed.) Ophelia, Suppl. 3: 147- 1 50. Kaut ky, H. & Foberg, M. 1991. Utbredning av vaxter och dj ur i McLachlan, J., Chen, I.C.M. & Edelstein, T. 1971. The culture of Monstera - recipientens fytobental. - Slutrapport till four species of Fucus under laboratory conditions. - Can. J. Miljoforskargruppen & Monsteras Bruk, Aqua Eco, Saltsjo­ Bot. 49: 1463-1469. Boo. 39 pp. (as Swedish EPA-report, revision, mimeographed). Molander, S. 1991. Detection, validity and specificity ofPollution­ Kautsky, H. & van der Maarel, E. 1990. Multivariate approaches Induced Community Tolerance (PICT). - Ph. D. Thesis, to the variation in benthic communities and environmental Dept. Plant Physiology, Univ. Goteborg. 30 pp. + 4 papers. vectors in the Baltic Sea. - Mar. Ecol. Prog. Ser. 60: 169- 1 84. Moss, B. 1 966. Polarity and apical dominance in Fucus vesiculosus. Kaut ky, H., Kautsky, U. & Nellbring, S. 1988. Distribution of - Br. Phycol. Bull. 3: 31-35. flora and fauna in an area receiving pulp mill effluents in the Mi.iller-Stoll, W.R. & Ki.inzenbach, R. 1956. Ober die trandort­ Baltic Sea. - Ophelia 28: 139- 155. bedingten Wuchsformen von Fucus vesiculosus in den Kautsky, L. & Kautsky, H. 1989. Algal diver ity and dominance Gewassern der Insel Hiddensee. - Arch. Protistenkunde 101: along gradients of stress and disturbance in marine environ­ 289-334. ment . - Vegetatio 83: 259-267. Odum, E.P. 1985. Trends expected in stressed ecosystems. - Kautsky, N. 1984. A battery operated, continuous-flow enclosure Bioscience 35: 419-422. for metabolism studie in benthic communities. - Mar. Bioi. Odum, H.T. & Odum, E.C. 1976. Energy basi for man and nature. 81: 47-52. - McGraw-Hill, New York. 297 pp. Kautsky, N. & Evans, S. 1987. Role of biodeposition by Mytilus Pekkari, S. 1973. Effects of sewage water on benthic vegetation. edulis in the circulation of matter and nutrients in a Baltic Nutrients and their influence on the algae in the Stockholm coastal ecosystem. - Mar. Ecol. Prog. Ser. 38: 20 1-212. archipelago during 1970. No. 6. -Oikos, Suppl. 15: 185-188. Kautsky, N., Kautsky, H., Kautsky, U. & Wcem, M. 1986. De­ Rietema, H. 1991. Evidence for ecotypic divergence between creased depth penetration of Fucus vesiculosus L. since the Phycodrys rubens populations from the Baltic Sea and North 1 940's indicate eutrophication of the Baltic Sea. - Mar. Ecol. Sea. -Bot. Mar. 34: 375-38 1. Prog. Ser. 28: 1-8. Ronnberg, 0. 1981. Traffic effects on rocky-shore algae in the Kautsky, U., Wallentinus, I. & Kautsky, N. 1984. Spring bloom Archipelago Sea, SW Finland. - Acta Acad. Abo. Ser. B. 41 dynamics of an epilithic microphytobenthic community in the (3): 1-86. northern Baltic Sea proper. - Ophelia, Suppl. 3: 89-99. Ronnberg, 0. & Roukolahti, C. 1986. Seasonal variation of algal Knight, M. & Parke, M. 1950. A biological study of Fucus epiphytes and phenolic content of Fucus vesiculosus in a vesiculosus L. and F. serratus L. - J. Mar. Bioi. Ass. U.K. 29: northern Baltic archipelago. - Ann. Bot. Fenn. 23: 317-323. 439-5 14. Ronnberg, 0., Adjers K., Ruokolahti, C. & Bondestam, M. 1990. Larsson, U., Elmgren, R. & Wulff, F. 1985. Eutrophication and the Fucus vesiculosus as an indicator of heavy metal availability Baltic Sea: Causes and consequences. - Ambio 14: 9- 14. in a fish farm recipient in the northern Baltic Sea. - Mar. Launiainen, J., Pokki, J., Vainio, J., Niemimaa, J. & Voipio, A. Pollut. Bull. 21: 388-392. 1989. Long-term changes in the Secchi depth in the northern Ronnberg, 0., Lehto, J. & Haahtela, I. 1985. Recent changes in the Baltic Sea.-XIV Geofysikanpaiva t Helsinki 2-4.5. 1 989, pp. occurrence of Fucus vesiculosus in the Archipelago Sea, SW 1 17-121. (In Finnish with English abstract.) Finland. - Ann. Bot. Fenn. 22: 23 1 -244.

Acta Phytogeogr. Suec. 78 48 H. Kautsky et al.

Ronnberg, 0., Ostmann, T. & Adjers, K. 1992. Effects of ferry Wrern, M. 1952. Rocky-shore algae in the Oregrund archipelago. traffic on the metal content of Fucus vesiculosus in the Aland -Acta Phytogeogr. Suec. 30: 1-298. archipelago, northern Baltic Sea. - Acta Phytogeogr. Suec. Wrern, M. 1965. A vista on the marine vegetation. - Acta 78: 95-99. Phytogeogr. Suec. 50: 15-28. Rosemarin, A., Mattsson, J., Lehtinen, K.-J., Notini, M. & Nylen, Wallentinus, I. 1976. Environmental influences on benthic E. 1986. Effects of pulp mill chlorate (C103 -) on Fucus macrovegetation in the Trosa-Asko area, northern Baltic Sea vesiculosus -A summary of projects. - Ophelia, Suppl. 4: proper. I. Hydrographical and chemical parameters, and the 219-224. macrophytic communities. - Contr. Asko Lab. Univ. Stock­ Rosemarin, A., Notini, M., Soderstrom, M., Jensen, S. & Landner, holm 15: 1-138. L. 1990. Fate and effects of pulp mill chlorophenolic 4,5,6- Wallentinus, I. 1978. Productivity studies on Baltic macroalgae ­ trichloroguaiacol in a model brackish water ecosystem. - Sci. Bot. Mar. 21: 365-380. Total Environ. 92: 69-89. Wallentinus, I. 1979. Environmental influences on benthic Russell, G. 1979. Heavy receptacles in e tuarine Fucus vesiculosus macrovegetation in the Trosa-Asko area, northern Baltic Sea L. - Estuar. Coast. Mar. Sci. 9: 659-66 1. proper. II. The ecology of macroalgae and submersed Russell, G. 1985a. Recent evolutionary changes in the algae ofthe phanerogams. - Contr. Asko Lab. Univ. Stockholm 25: 1- Baltic Sea. - Br. Phycol. J. 20: 87-1 04. 210. Russell, G. 1 985b. Some anatomical and physiological differences Wallentinus, I. 1981. Phytobenthos. - In: Melvasalo, T., Pawlak, in Chorda filum from coastal waters of Finland and Great J., Grasshof, K., Thorell, L. & Tsiban, A. (eds.) Assessment of Britain. - J. Mar. Bioi. Ass. U.K. 65: 343-348. the effects of pollution on the natural resources of the Baltic Scanferlato, V .S. & Cairns, J. 1990. Effect of sediment-associated Sea 1980. Baltic Sea Environ. Proc. 5 B: 322-342. copper on ecological structure and function of aquatic micro­ W allentinus, I. 1 983. VegetationskHidda bottnar. - In: Eutrofiering cosms. - Aquat. Toxicol. 18: 23-34. i marin miljo - 6stersjon. Delrapport V. Asko Lab., Univ. Schindler, D.W. 1990. Experimental perturbation of whole lakes Stockholm. 57 pp. (Mimeographed.) as test of hypotheses concerning ecosystem structure and Wallentinus, I. 1984a. Comparisons of nutrient uptake rates for function. - Oikos 57: 25-41. Baltic macroalgae with different thallus morpho1ogies. - Segerstrale, S. 1944. Weitere Studien i.iberdie Tierwelt der Fucus­ Mar. Biol. 80: 215-225. Vegetation an der Si.idki.iste Finnlands. - Soc. Sci. Fenn. Wallentinus, I. 1984b. Partitioning of nutrient uptake between Commentat. Bioi. 9(4): 1-28. annual and perennial seaweeds in a Baltic archipelago area. ­ Snoeijs, P.J.M. & Kautsky, U. 1989. Effects of ice-break on the Hydrobiologia 116/ 1 17: 363-370. structure and dynamics of a benthic diatom community in the Wallentinus, I. 1991. The Baltic Sea gradient. - In: Mathieson, northern Baltic Sea. - Bot. Mar. 32: 547-562. A.C. & Nienhus, P.H. (eds.) Ecosystems of the World 24. Vernet, P. & Harper, J.L. 1980. The cost of sex in seaweeds. ­ Intertidal and littoral ecosystems. Elsevier, Amsterdam. pp. Biol. J. Linnean Soc. 13: 129- 138. 83-108. Vogt, H. & Schramm, W. 1991. Conspicuous decline of Fucus in WiJliams, P.J. LeB. 1984. Bacterial production in the marin food Kiel Bay (Western Baltic): what are the causes?- Mar. Ecol. chain: the emperor's new suit of clothes?- In: Fasham M.J.R. Prog. Ser. 69: 1 89- 1 94. (ed.) Flows of energy and materials in marine ecosystems. von Wachenfeldt, T. 1975. Marine benthic algae and the environ­ Plenum Publ. Corp., New York. pp. 27 1 -299. ment in the 6resund. I-HI. - Ph. D. Thesis, Lund Univ. 328 Wright, P.J. & Reed, R.H. 1990. Effects of osmotic stress on pp. gamete size, rhizoid initiation and germling growth in fucoid algae. - Br. Phycol. J. 25: 149- 155.

Acta Phytogeogr. Suec. 78 Contribution to the seaweed flora of Sweden: New or otherwise interesting records from the west coast

fan Karlsson, Mats Kuylenstierna & Per Aberg

Abstract Karlsson, J ., Kuylenstiema, M. & Aberg, P. 1992. Contribution to the seaweed flora of

Sweden: New or otherwise interesting records from the west coast - Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-7210-078-8.

Records of attached seaweeds new to the flora of Sweden and record of very rare or otherwise interesting species from the west coast are presented with notes on their morphology, distribution and ecology. Platoma bairdii, Schmitzia hiscockiana, Sphaerococcus coronopi­ fo lius, Cryptopleura ramosa, Hypoglossum hypoglossoides, Delamarea attenuata, Sargassum muticum and Protomonostroma undulatum are additions to the flora recorded during the last twenty years. Twenty-four very rare or otherwise interesting species are also listed. Some species previously considered as rare, and some of the new finds, were found to be common. Proposed explanations for the increasing amount of records are: (1) methodological reasons (diving vs. dredging); (2) increased number of visits to wave-exposed habitats; (3) the occurrence of favourable years resulting in higher abundances. Several species are considered as genuinely rare in their entire geographical distribution area, while some have their present northerndi stribution boundary at the Swedish west coa t.

Keywords: Estuarine; Exposed habitat; Rare algae; Skagerrak; Temporal variation.

Department of Marine Botany, University of Goteborg, Car[ Skottsbergs Gata 22, S-413 19 Goteborg, Sweden.

Introduction Material and Methods

Apart from major geological events, the large scale geo­ The Swedish west coast is at the same latitude (ea. 58° N) as graphical distribution of seaweeds depends on how species northernScotland. With respect to the hydrography there are have adapted to environmental variables correlated with two main differences which separate the Swedish west coast latitude (e.g. temperature, day length, seasonality), and to from the genuine marine environment in Scotland: the hydrographical conditions (e.g. tides, temperature, salinity, almost complete lack of tidal water, and the pronounced nutrition). The intensified use of SCUBA-diving among surface salinity gradient found when going from the south to marine botanists in Sweden has improved knowledge of the the north. distribution of common algae, as well as of more rare Irregular changes of the sea level due to winds and species. It has also led to the addition of several species new atmospheric pressure often exceed the tidal range (max. 0.3 to the marine flora of Sweden and Scandinavia, expanding m), resulting in a difference between high and low water of their geographical distribution further to the north than as much as 2 m within a year (Johannesson 1989). The previously known. impact of non-predictable water changes is an important The aim of this paper is to present observations ofnew or structuring mechanism for all shallow-living benthic algae, otherwise interesting algae that have been assembled over and the absence of regular changes may explain why some the last twenty years in the area between the city ofGoteborg species Jiving in the upper littoral or supralittoral, such as and the Norwegian border (Fig. 1). the brown alga Pelvetia canaliculata (L.) Done. et Thur., is

Acta Phytogeogr. Suec. 78 50 J. Karlsson et al.

A '--..__ ldefjorden concentrated mainly on the Nordre lv Estuary (Kuylen­ stierna 1989, 1990). The KMBS area includes the fj ord Gullmarsfjorden and the archipelago west of its mouth. The Koster area includes the skerries of Segelskaren, both sides of the Kosterfjorden and the surroundings of the Tj amo Marine Biological Laboratory (TML). Gullmarsfjorden The data from the Goteborg area were the results of surveys made between 1975 and 1980 (Kuylenstierna 1989, SKAGERRAK 1990). These studies were the first thorough studies in an estuarine environment on the Swedish west coast and the SWEDEN experience achieved triggered additional finds at other lo­ 58°N calities with similar habitats. For a detailed description of the Goteborg area and the techniques used during the work in this area and for further discussions on the results of these studies see Ku y lenstierna( 1 989, 1 990) and J enneborg ( 1 986). The Vadero and Koster areas were some of the first < geographical areas dealt with in Swedish phycology (Areschoug 1850, Ekman 1857, Kj ellman 1872, 1878). Most of the new data from these areas have been collected during the period 1983 to 1991. The Koster area is gradually becoming better known after the establishment of TML �

Laholms- still suffers from being relatively isolated, and work in the I northern part of this area is hampered by natural con­ DE servation restrictions. The kelp Laminaria hyperborea 'l� b"� (Gunn.) Fosl. dominates at depths between 6 and 12 m (Lunneryd & Aberg 1983). Non-crustose algae, mainly 6resund l Phyllophora crispa (Huds.) Dixon, P. truncata (Pallas) WE 50 km / � , '\ Zinova and Phycodrys rubens (L.) Batt. are here recorded ?;/ down to a depth of at least 32 m. Sediment bottoms start to Fig. 1. The Swedi h we t coast. The shaded area represents the occur at depths between 20 and 25 m and are dominated by distribution of Sargassum muticum in 1991. For abbreviations, see small stones, gravel and shell fragments. Ripples are found text. down to at least 30 m. Most records are from field work carried out as qualitative collections of algae using the SCUBA-technique unless not found in Sweden. otherwise stated. Dredging has only been used to a minor Water input from the North Sea results in surface salinities extent. The survey of the Vadero area (Lunneryd & Aberg ranging from 25 to 34 %o in the Skagerrak (Rosenberg et al. 1983), part of the field work on Schmitzia spp. (Karlsson 1991). Stratification of the water is most pronounced in the 1990) and the studies on Sargassum muticum in the Koster Kattegat, but is also found along the Skagerrak coast. Tem­ area were carried out as semi-quantitative studies placing poral variations in salinity are more frequent in the northern 0.25 m2 quadrats along a transect line, recording percentage part due to weaker stratification and different origins of the cover or number and sizes of individuals. water masses (Rosenberg et al. 1991). Decreasing salinity Both fresh material, and specimens preserved in alcohol causes a decrease in species number, depauperization of or 4% formalin, were examined using a camera equipped thalli, submergence of species living in the littoral or upper Reichert Zetopan or an Olympus BH2 light microscope. A sublittoral and a shift towards more brackish water species Phillips 301 transmission electron microscope (TEM) was when going south. Local freshwater influences cause the used in the studies of Rhodella cf. maculata. Macro photos same responses on a smaller scale. were taken using an Olympus SZH Stereomicroscope. Slide Most of the records presented in this paper have been preparations were made from liquid preserved material, compiled from visits to the Koster area, the Vadero area, the stained with aniline blue, mounted in either Karo (corn

KMBS area (KMBS = the Kristineberg Marine Biological syrup) or in glycerine jelly. Species in culture were exposed Station) and the Goteborg area (Fig. 1) during the period to a 14: 10 h L:D regime, using cool fluorescent light (40 !J.E 1 2 between 1972 and 1991. In the Goteborg area studies have s- m- ), with an ambient temperature of 10 oc. The culture

Acta Phytogeogr. Suec. 78 Contributions to the seaweed flora of Sweden 51

media was based on von Stosch (1964), with salinity con­ S. pseudocrispa ssp. scandinavica, based on more pointed centrations of 0, 20, 30 and 34 %o. apices and on different arrangement and morphology of the Taxa preceded by an asterisk ( *) in the text are new for cortical cells, compared with French and British material. Sweden. Unless otherwise stated the records were made The majority of the specimens found in 1989-9 1, when between 1972 and 1991 by the present authors. Voucher examined fresh, do not support this proposal (Fig. 2k-l). The specimens are deposited in the herbarium at the Department cortical cells were observed to become more rounded and of Marine Botany, University of Goteborg (GB), as well as swollen when transferred to alcohol or formalin, disrupting in personal herbaria unless otherwise stated. Records in the cell pattern of the fresh cortical surface. Also, the slow adjacent Norwegian and Danish waters cover fi nds until growth rate proposed by Maggs & Guiry (1982a) as moni­ autumn 1990 and have been compiled from literature and tored by a rich flora of epiphytes on their material is prob­ through personal communication. ably due to the use of drift material. In the recent material found during this study epiphytes were scarce and restricted to old plants found in the end of September. In Norway S. pseudocrispa has only been found attached Observations on two occasions (Baardseth 1941, and at Jus to, province of Aust-Agder, T. Wennberg pers. comm.). Danish reports deal with specimens washed ashore on the Danish west Bangiophyceae coast (Rosenvinge 1931, Nielsen 1982).

Audouinella rosulata (Rosenv.) Dixon (Nemaliales)- This minute species is distinguished by a characteristic andro­ Phymatolithon calcareum (Pallas) Adey & McKibbin phore which was easily recognized in the material collected (Corallinales) -This branched corallineacean was found in August 1975 and later on at exposed sites in the Goteborg in November 1991 at one locality in the Koster area. One area (Kuylenstierna 1990). It grew on Ectocarpus sp. [epi­ sparsely branched specimen, approximately 50 mm long, phytic on Chordaria flagellifo rmis (O.F. Mtill.) C. Ag.]. with a diameter of approximately 3 mm, was found among Both male plants, with antheridia on their androphores, and gravel and shell fragments at a depth of 22 m. P. calcareum plants carrying monosporangia were observed. was previously recorded alive on two occasions at one There are a few other records of the genuine A. rosulata locality in the KMBS area (Suneson 1 958, as Lithothamnion from the Swedish west coast: in the Oresund (Fig. 1) (von calcareum (Pallas) Aresch.). Dead specimens have been Wachenfeldt 1975 as Kylinia rosulata Rosenv.), in drift recorded on the shore in the Vadero area (Suneson 1958, P. from the eastern Kattegat [Stegenga & van Wissen 1979 as A. pers. obs.) and were also dredged in the Koster area Acrochaetium strictum (Rosenv.) Hamel] and from the during the 1980s (J. K. pers. obs.), implying the presence of KMBS area (Stegenga & van Wissen 1979). The closely this species. In Denmark P. calcareum was recorded in the resembling species Chromastrum kylinoides (Feldm.) Kattegat at depths between 17 and 30 m (Rosenvinge 1931) Stegenga & van Wissen was misinterpreted by Kylin (1 944) and in Norway finds have been restricted to the southwest­ and erroneously introduced as Kylinia rosulata Rosenv. ern part of the country (Foslie 1905, Levring 1937). into his red algal flora (Feldmann 1 958).A. rosulata has also been re-found as drift in the SW Kattegat near its Danish Dudresnaya verticillata (With.) Le Jol. (Cryptonemiales) type locality (Moestrup et al. 1975). - This alga was collected in August-September 1991 at five very exposed localities in the westernmost parts of the Scinaia pseudocrispa (Clem.) Wynne (Nemaliales) - This Vadero and Koster areas. The species grew at depths be­ species was first recorded in Sweden in 1925 by Gertz tween 17 and 27 m on small stones, cobbles and shell [1926, as Scinaiafurcellata (Turn.) Biv.] from the strait of fragments. Plant sizes ranged from 5-80 mm and the major­ Strommarna, in the KMBS area, followed by another find in ity of the plants carried carpogonia, as well as developing 1926 (Kylin 1933). From 1989 to 1991 it was recorded from cystocarps. D. verticillata can, at a quick glance, be con­ a wide variety of localities in the northern part of the fused with Schmitzia neapolitana when juvenile, but in province of BohusHin, characteristically on a substrate of D. verticillata the uniaxial structure can only be seen close mixed pebbles and shells, at a high rate of water exchange to the apex of a shoot, as it is soon obscured by down­ (either at extremely exposed sites or in channels with strong growing rhizoidal filaments arising at the base of each currents). The plants were found at depths between 5 and whorl branchlet. The result is a non-translucent, much firmer 22 m from the beginning of July until the end of September, and compact thallus, characters which can be used when reaching a maximum length of approximately 100 mm in distinguishing between the two species in the field. When the beginning of September. Cystocarps were found from fertile, D. verticillata exhibits characteristic carpogonial the end of July and onwards. branches, 7-9 cells long, and conspicuous 12-celled auxil­ Maggs and Guiry (1982a) used preserved German, Dan­ iary branches. The cells of the whorls are more elongate ish and Swedish material to propose a new subspecies, than those of S. neapolitana. The life history is isomorphic,

Acta Phytogeogr. Suec. 78 52 1. Karlsson et al. tetrasporangia being zonate. Phyllophora traillii Holmes ex Batters (Gigartinales) - D. verticillata was recorded in the Vadero area by Ekman Wrern (1958) was the first to repmt this species in Sweden ( 1 857) and Luhr 1 870 (in Kylin 1944). Wrem(1 961)dredged (the KMBS area). More recently, it was also collected in the it in the same area, and some years earlier in the KMBS area Koster area (1978, I. Wallentinus pers. comm.). Since (Wrern 1958). The pecimen collected by Ekman in about 1985, it is found to be common in the Koster area. There are 1850-52, now at the Swedish Museum of Natural History, also some additional finds in 1973 from the Kattegat at the Stockholm, is impossible to re-examine, being dried and in southern head of the bay Laholm bukten (Fig. 1) at a depth poor condition. From Denmark the species is known from of only 4 m (T Wennberg pers. comm.). Normally, this the northern Kattegat (Christensen 1975). In Norway it was species is confined to exposed sites and found at depths recorded twice in the outer 0 lofjord by Sundene (1953, below 10 m, on the leeward sides of boulders and steep 1959 unpubl. herb. mtrl., Dept. of Marine Botany, Univer­ slopes, where individuals in their most typical growth form sity of Oslo), although only the latter material remains (J. may cover each other like roofing-tiles. The species is easily Rueness pers. comm.). identified by its small size and by the characteristic prolif­ erations from the thallus margin containing reproductive Gracilaria verrucosa (Huds.) Papenf. (Gigartinales)-This structures (Schotter 1968). In Denmark this species is re­ species was reported in Sweden only a few times (Kylin ported from a few localities in the Kattegat by Rosenvinge 1944, Wrern 1958, Wallentinus 1972), but it is now com­ (193 1). mon at sheltered sites in the Koster area from June until October, although plants can be found throughout the year. *Platoma bairdii (Farl.) Kuck. (Gigartinales) - This spe­ In Zostera marina L. beds, sterile specimens can frequently cies was found in the first half of July 1991 at two different be found in loose-lying masses. In more exposed and sandier sites in the southwestern part of the Koster area at depths habitats, fertile individuals attached to pebbles and shells, between 15 and 19 m. Both female gametophytes (Fig. 2f) are frequently found down to a depth of 12 m. During and mature tetrasporophytes (Figs. 2e and g) were collected August to September, plants with a length of350 mm are not growing on small, relatively naked stones. The curved uncommon. In Denmark attached specimens have been individuals arose as single or in groups from a basal discoid recorded from the Skagerrak coast, but records of loose crust, of about 0.5-2 mm in diameter. Both life history lying plants include the Danish Kattegat (Christensen et al. stages could be found on the same piece of substrate, 1985). In Norway it occurs along the Skagerrak and the west although not emanating from the same basal disc. Plant coast (Rueness 1977). sizes ranged from just a few mm to 15 mm. Only a few individuals were branched, up to three times. When revisit­ Halarachnion ligulatum (Woodw.) Kiitz. (Gigartinales) ­ ing the localities at the end of August 1991, no plants were Fertile gametophytes of this pecies have been recorded found, although other species (Schmitzia hiscockiana, between May and August every summer since 1984 in the S. neapolitana, Scinaia pseudocrispa and Halarachnion Koster area. The species was found to be common at ex­ ligulatum), which started their growth in July, still thrived. posed sites, growing on gravel at depths between 15 and 25 The taxonomic status of P. bairdii pends further investiga­ m. Considerable variation in plant sizes was noted between tion (Norris & Bucher 1977), and the morphology of the years, with sizes ranging from 5 to 150 mm. The thalli were thallus and the reproductive structures of the Swedish speci­ mostly dichotomously branched. H. ligulatum was previ­ mens will be discussed more in detail in a future paper. ously recorded only a few times in Sweden (Ekman 1857, Little is known about the ecology of P. bairdii. It was Luhr 1870 in Suneson 1939, Suneson 1939, Wrern19 58). In originally described as Nemastoma bairdii by Farlow ( 1 875) the private herbarium of I. Wallentinus, University ofGote­ from Massachusetts, and some additional records are known borg, there are also some finds from 197 5 and 197 8 from the from eastern Canada (Edelstein et al. 1967, Mathieson et al. Koster area. 1969). Kuckuck (19 12) placed it into the genus Platoma. The tetrasporic stage of H. ligulatum is reported to be The species was recorded in England in 1853 (Batters 1900, similar to the non-coralline crust Cruoria rosea Crouan frat. see also Dixon 1964 ), in Helgoland, Germany (Kuckuck (Boillot 1972), or to a crust very similar in appearance 1912, Kornman & Sahling 1977) and in Denmark in 1915 (South et al. 1972, Dixon & Irvine 1977). C. rosea was (Rosenvinge 1931). previously observed in the Vadero area (Wrern 1961) and in the Koster area (August 1983, A. Athanasiadis pers. *Schmitzia hiscockiana Maggs & Guiry (Gigartinales) ­ comm.). H. ligulatum was found sporadically in Denmark This species was described as late as 1985 based on material (Rosenvinge 1931, Christensen et al. 1985) and in Norway from the British Isles (Maggs & Guiry 1985). It was col­ (Rueness 1977). lected in the Koster area in 1986 (Karlsson 1990), and in 1989 to 1991. The Swedish specimens (Fig. 2a) agree with the descri ption given by Maggs & Guiry (1985). S. hiscockiana might be identical with the Bertholdia species that was recorded in 1958 and 1959 by Wrern (1961) from

Acta Phytogeogr. Suec. 78 Contributions to the seaweed flora of Sweden 53

b

h

Fig. 2. Selected records of algae from the Koster (a-1) and the Vadero (m) areas. (a) Schmitzia hiscockiana. Habit of gametophyte. Lilla ArsklflVet, 16 m. Sept., 1989. Scale: 10 mm. - (b-d) Sphaerococcus coronopiolius.f (b-e) Habit of gametophytes. Scale: 10 mm. (b) V. Segelskar, 22 m. 7.9. 1990. Leg & det. J. Karlsson & A. Lundberg. (c) Ursholmen, 18 m. 15.11.1991. (d) Frond with fishbone-like pattern.Scale: 500 f..Lm. - (e-g) Platoma bairdii. (Ursholmen, 18 m. 11.7.1991. (e) Habit of tetrasporophyte. Scale: 5 mm. (f)Fe male plant with three-celled carpogonial branch. (t) = trichogyne, (c) = carpogonia, (g) =gland cell. Scale: 25 f..Lm. (g) Cruciate tetrasporangia scattered in cortex. Scale: 25 f..Lm. - (h-j) Cryptopleura ramosa.

(h) Habit of prostrate form. Ulvillen, 21 m. 3.8.1989. Scale: 10 mm. (i) Habit of epiphyte. Klavningen by Morholmen, 15 m. 8.9. 1 990.

Scale: 30 mm.(j ) Frond of epiphyte with microscopic veins and rhizoidal hooks. Scale: 500 f..Lm. - (k-1) Scinaia pseudocrispa. (k) Habit. Inre Vattenholmen, 10 m. 30.8.1 989. Scale: 30 mm. (1) Pattern of cells in surface view. Scale: 100 !liD. - (m) Hypoglossum hypoglossoides. Habit. St Valeskar, 27 m. 9.8. 1991. Scale: 10 mm.

Acta Phytogeogr. Suec. 78 54 J. Karlsson et al.

the Koster and Vadero areas (Karlsson 1990). In Sweden, as Guiry 1987). These authors also provide a description of well as in Britain, it seems to be confined to exposed how to distinguish between the two species. habitats with a temporarily mobile substrate; small boul­ ders, pebbles and shell fragments at depths between 1 0 and Chondria dasyphylla (Woodw.) C. Ag. (Ceramiales) - 20 m. Except for the British (Hiscock & Maggs 1984, This species was first recorded in the Koster area by Are­ Maggs & Guiry 1985) and Swedish (Karlsson 1990) mate­ schoug (1850); and more than a hundred years later it was rial of this species no other records are known (Wilce & re-found in the same area (September 1973, I Wallentinus Sears 1991). pers. comm.). This find, consisting of a tetrasporic, non­ attached plant dredged from a shell bottom at 10 m depth Schmitzia neapo!itana (Berth.) Lagerh. ex Silva (Gigarti­ near TML in the Koster area, was later fol1owed by addi­ nales) - S. neapolitana, which is terete in contrast to the tional ones which were found attached to pebbles and shell complanate S. hiscockiana, was first collected in Sweden in fragments. A few years later it was reported for the first time the Vadero area in 1870 by A. E. Luhr (Wrern 1961). The in Norway (Asen 1980). In Denmark it was recorded as drift identification is based on the vegetative characters of a on the Skagerrak coast in 1959 (Nielsen 1982), 1968 and single specimen from Wrern'spri vate herbarium (M. Wrern 1972 (T. Christensen pers. comm.). In the Koster area it is pers. comm.). It was re-found by Wrern in 1958 at the same now observed every year from July to October in various locality (Wrern 1961), and in the Koster area in 1989 at kinds of habitats, except for very exposed ones, as an depths between 10 and 22 m in the same type of habitats as epiphyte as well as growing on pebbles and shells. Plant S. hiscockiana (Karlsson 1990). Since 1989 it has been sizes reach 150 mm, although sizes between 40-50 mm are found from June until September in the Koster and Vadero more common. areas. This species is ephemeral and rare in its entire distri­ bution area and apart from the Swedish finds, S. neapolitana *Cryptopleura ramosa (Huds.) Kylin ex Newton (Cera­ has only been reported from Naples, Italy (Berthold 1884), rniales) - Attached specimens of this species were for the Brittany, France (Feldmann 1954, Cabioch 1969), SW Bri­ first time recorded in August 1989 in the southern part of the tain (Hiscock & Maggs 1984), and Greece (Athanasiadis Koster area. Small, to 45 mm, palmate and sterile specimens 1987). (Fig. 2h) showing typical iridescence and rnicroscopical veins, were found at 21 m depth, growing prostrate on *Sphaerococcus coronopifolius Stackh. (Gigartinales) - boulders. In 1990 this species was common from June This species which is new to Sweden was first found in the onward and throughout the year at exposed sites in the southwestern part of the Koster area in September 1990, Koster area at depths between 15 and 22 m, growing both as growing on bedrock at a depth of 22 m. From August 1991 prostrate on boulders and as an epiphyte (Fig. 2i) on to February 1992 records were made at the same locality, Phyllophora spp., Phycodrys rubens and on Corallina and at three new sites in the Koster area. The internal officina/is L. In November 1990 it was found as shallow a fishbone-like pattern (Fig. 2d) of the uniaxial thallus was 3.5 m. Plant lengths reached 250 mm in September. In 1991, clearly visible in slight magnification, or when held against plants did not appear until August, but were still found by the light, in the specimens from August-October, but was the middle of November. Some sites exhibiting luxurious more obscured in the plants found during late autumn and growth in 1990 were devoid of any macroscopic remains winter. Thalli found in August were between 5-l 0 mm long during 1991. All plants found so far have been sterile or (Fig. 2b), while the length was 25-50 mm in the autumn and tetrasporophytes with sori at the blade margins in young winter plants of 1991/92, with more branched thalli (Fig. plants, or in special proliferations from the margins in older 2c). Cystocarpic protuberances were recorded in February plants or on old parts. Old plants exhibited rnicroveins in the 1992, but these were all empty, so the question of reproduc­ upper parts (Fig. 2j ), and distinct macroveins in the lower tion in Swedish waters still remains. The tetrasporophyte of parts. Sphaerococcus is reported to be a crust, previously known C. ramosa has been shown to exhibit considerable mor­ as Haematocelis fissurata Crouan frat. (Maggs & Guiry phological variation, and the ability to form hook-like pro­ 1982b). liferations from the thallus margin sometimes makes it In Europe attached S. coronopifolius has not been re­ difficult to distinguish between species of Acrosorium and ported from north of the Isle of Man, Great Britain (Dixon Cryptopleura (Wynne 1983, 1989). In the Swedish mate­ & lrvine 1977). When young, this species may be confused rial, no hookforming plants have been found. The prostrate with two other red algae occurring in the same type of forms (Fig. 2h), with rounded apices and rhizoids produced habitat in Sweden: Callophyllis cristata (C. Ag.) Kiitz.and from just behind the upper margins on the down-facing side Plocamium cartilagineum (L.) Dixon, which, however, both of the blade, correspond to Acrosorium reptans (Crouan lack the internal fishbone-pattern. This characteristic pat­ frat.) Kylin, which is now considered merely as a modifica­ tern is only known to occur in one other species in Europe: tion of C. ramosa to a life in very exposed habitats. (Wynne Pikea californica Harvey, a Pacific native, which at present 1989 and references therein). However, rhizoidal structures is recorded only from the Scilly Isles, SW Britain (Maggs & were also common on young plants, or on parts of full-

Acta Phytogeogr. Suec. 78 Contributions to the seaweed flora of Sweden 55

grown plants growing as epiphytes (Fig. 2j ). found are of the f. disticha described by Feldmann­ C. ramosa was previously recorded in Sweden only as Mazoyer (1940), which is widely distributed in western drift specimens from the Koster area in October 1975. Europe (Dixon 1963). However, some of the plants express (T. Wennberg, B. Rex pers. comm.). Specimens deposited type habitus, with four whorl branches on each axial cell, in by L.-H. Jenneborg in the herbarium at GB originate from contrast to the plume-like distichous forms, with only two the same occasion. C. ramosa has not been found along the opposite branches in the same level. In November 1991 the Norwegian Skagerrak coast, although some records were majority ofthe plants carried unbranched filaments, up to 30 made on the west coast (Baardseth 1974, Rueness et al. mm long, continuing from the tips of the main branches. 1990, J. Rueness pers. comm.). Plants grew together in distinct tufts, the bases filted together by rhizoids produced from the basal parts. Plant sizes, top *Hypoglossum hypoglossoides (Stackh.) Coli. & Herv. filaments excluded, varied between 20 and 50 mm. Neither (Ceramiales) - During a survey of the algal vegetation in fertile gametophytes, nor tetrasporangia have been found in the Vadero area in July 1983, this species was found for the Sweden. first time in Scandinavia at one of the outermost skerries in the archipelago (Lunneryd & Aberg 1983). In August 1990 additional finds were made at the same site (A. Athanasiadis Fucophyceae pers. comm.). At the end of October the same year no plants were found (J. K. pers. obs.) but during 1991 it was found *Delamarea attenuata (Kjellm.) Rosenv. (Tilopteridales) again at the same, and at another locality in the Vadero area. - This species was first found in May 1980 at exposed On the Swedish west coast H. hypoglossoides reaches a localities in the western part of the Goteborg area, and since length of 40 mm, a width of 4 mm and grows in rosette-like then it has been sparsely observed there in spring tufts (Fig. 2m) or in elongated patches on rock free from (Kuylenstierna 1990). Specimens have been found growing detritus, or at sharp edges of big boulders at depths between on rock at depths between 1 and 3 m. Plants found in May 22 and 25 m. Some of the collected specimens carried 1980 carried unilocular sporangia and were about 40 mm tetrasporangia. The nearest reported records are from the long. When cultured, unispores developed into Hecatonema­ Shetland Islands (Tittley et al. 1976). like thalli with plurilocular sporangia. When ageing, D. attenuata sometimes becomes hollow and is then easily Seirospora seirosperma (Harv.) Dixon (Cerarniales) - confused with Scytosiphon lomentaria (Lyngb.) Link. How­ One tiny, 20 mm long, specimen with rows of2-5 seirospores ever, D. attenuata is distinguished by its large and rounded was collected in September 1991 in the Koster area at a surface cells (paraphysis) and by more than one discoid depth of 15 m, growing on the holdfast of Phyllophora plastid per cell. pseudoceranoides (Gmel.) Newroth & Taylor. Sterile speci­ The genus Delamarea is mainly found in the arctic and mens referred to as S. seirosperma have previously been the subarctic regions, and D. attenuata is considered as rare found in the Koster area. The apparent lack of sexual in northern Norway (Rueness 1977). In Denmark it is structures, which seems to be a general phenomenon in known from the Kattegat (Rosenvinge & Lund 1947, S. seirosperma, is discussed by Dixon (1971). In Sweden, Pedersen 1974a). The latter author described two types of only a few finds of this delicate and richly branched red erect thalli; one type corresponding to the Swedish finds, alga, are known from the northern part of the west coast and one type carrying plurilocular sporangia, which has not (Areschoug 1850, Kylin 1908, Wrern 1958, herb. I. been met with in Sweden. Wallentinus 1974). Kylin (1908) and Wrern (1958) consid­ ered it to be rare in the lower sublittoral at moderately Tilopteris mertensii (Turn. in Sm.) Kiitz. (Tilopteridales)­ exposed localities. In Denmark, where it is recorded from Some 50 mm long specimens with monosporangia were the western part of the Kattegat, as well as in Norway, it is found on stones at 10 m depth in August 1979 in the rare and occurs at depths between 10 and 20 m (Rosenvinge Goteborg area (Kuylenstierna 1990). Since Kj ellman ( 1 878) 1931, Rueness 1977). recorded T. mertensii in the KMBS area, the few reports of this species are from the Danish (Rosenvinge & Lund 1941, Spondylothamnion multifidum (Huds.) Nag. (Cerarniales) Moestrup et al. 1975) and the Norwegian coasts (Rueness -This species was first found in Sweden by Wrern(1 958) 1977) despite intense searches in Sweden (Wrern 1958). on bedrock at exposed sites east of the Vadero area and in the KMBS area. Later, it was also recorded in the Koster area Botrytella micromora Bory (Ectocarpales) - In March, (Wallentinus 1972, herb. I. Wallentinus 1974). In August­ 1977 a few, up to 35 mm high plants were found growing on November 1990 and 1991 it was found growing together stones at an exposed locality in the western part of the with Compsothamnion gracillimum De Toni and Ptero­ Goteborg area at depths between 0.5 and 3 m [Kuylenstierna siphonia parasitica (Huds.) Falkenb. on plain bedrock at 1990, as Sorocarpus micromorus (Bory) Silva]. Additional several localities at the exposed western side of the Koster specimens were collected in May-June. Plurilocular area, at depths between 18 and 25 m. Most of the specimens sporangia were observed in March and May. Gross m or-

Acta Phytogeogr. Suec. 78 56 J. Karlsson et al.

phology agreed with the description given by Pedersen March. Plurilocular sporangia were recorded in April-Au­ (1974b). This species was previously recorded in Sweden; gust, and in October. Unilocular sporangia were only met in the KMBS area by Kylin (1947), who considered it as with once (June). When cultured in media with salinities of rare, as well as in the southeastern part of the Kattegat 30, 20 and 0 %o, growth gradually decreased, but did not (T. Wennberg pers. comm.). In Denmark this species enters stop. Plurilocular sporangia dominated, with unilocular the western Baltic Sea (Christensen et al. 1985) fo llowing sporangia occurring twice, on one occasion with plurilo­ the 1 5%o halocline. In Norway it was recorded once from the cular sporangia on the same thallus (Kuylenstiema 1990). west coast (Munda 1964). P.fluviatile has also been reported from freshwater habitats (Dop 1979) and from several other estuaries along the Botrytellareinboldii (Reinke) Kornm.& Sahl. (Ectocarpales) Swedish west coast (the fj ords of Idefjorden, Gullmars­ -This species was reported by Wrern [1958, as Polytretus fj orden and Kungsbackafjorden, see Fig. 1) (Kuylenstierna reinboldii (Reinke) Sauv.] from the KMBS area. More 1990). Wrern (1952) found it to be common in the archi­ recently (August 1979) it was also observed in the Goteborg pelago ofbregrund in the Baltic Sea, with a salinity of about area growing at a depth of 10 m (Kuylenstierna 1990, as 5 %o. P. reinboldii). Although sterile in the field, plurilocular P. fluviatile was recorded in the southern Kattegat by sporangia occurred in abundance when cultured (Kuylen­ Wennberg (1987) as Sorapion kj ellmanii (Wille) Rosenv. stierna 1989, plate 4). Reports of true unilocular sporangia Pedersen (1981) considered P.fluviatile to be a stage in the in this species have been regarded as doubtful (Rosenvinge life history of S. kj ellmanii, which still needs to be further & Lund 1941, Jenneborg 1977, Kurogi 1978) and structures investigated. According to Wrern(p ers. comm.) P.fluviatile resembling unilocular sporangia in the now recorded mate­ and S. kjellmanii should still be regarded as separate taxa. rial were found to be fungus infections (S. Nygren pers. S. kj ellmanii was previously recorded on the Swedish west comm.). B. reinboldii has been recorded a few times in coast by Wrern (1958). Denmark (Rosenvinge & Lund 1941, Nielsen & Dahl 1992). Colpomenia peregrina Sauv. (Scytosiphonales) - This is Kuckuckia spinosa (Kiitz.) Kuck. (Ectocarpales) - This one of the species that has been introduced into Scandi­ tiny brown alga was first collected in October 1978 in the navian waters in recent times. Originally a Pacific native, it western part of the Goteborg area at a depth of 6 m was first observed in Europe on the French west coast in (Kuylenstierna 1990), and later on in the KMBS area in 1906 (Sauvageau 1918). It has been known from Denmark September 1981. Specimens from the KMBS area some­ (Lund 1942) and Norway (Braarud 1950, Rueness et al. times lacked sheaths. Culture studies of Kuckuckia from the 1990) since the 1930s, and was found for the first time in Goteborg area revealed a direct development through both Sweden in the KMBS area in 1950 (Suneson 1953). Since plurilocular and unilocular porangia on the same indi­ 1975 it has regularly been observed in the Koster area, both vidual, plants reaching sizes of 40-50 mm. Chromosome as drift and as attached (B. Rex pers. comm.). There seem to numbers of the two reproductive structures were compara­ be two temporal maxima in occurrence: one in April-May, ble (20-22 in plurilocular, 22-26 in unilocular sporangia) and one in November. In 1990, it was very common from (S. Nygren pers. comm.). The separation of K. kylinii Cardi­ March until May, with a maximum thallus diameter of nal from K. spinosa was questioned by Pedersen (1989), approximately 300 mm. It mainly grew as an epiphyte in who showed that the variation in cell diameters and the rather sheltered conditions, at depths between 0.3 and 9 m. occurrence of a basal sheath or not (which are the two major By the end of May all plants had disappeared. During the characteristics used when separating the two taxa), were spring of 1991 C. peregrina was more sparse than in 1990, purely the results of the ontogeny in K. spinosa. In old but was again frequent in November. cultures of the present material the cell diameters of the two taxa overlapped and basal sheaths were not seen in Sporochnus pedunculatus (Huds.) C. Ag. (Sporochnales) K. kylinii. K. spinosa has previously been reported as rare in - Since 1989 this species has regularly been found from the KMBS area, growing on Dilsea carnosa (Schmidel) July until October at different localities in the Koster and Kuntze [Kylin 1947 as K. crinigera (Kuck.) Hamel.]. Vadero areas, where it occurs on shells [in particular the empty shells of Arctica islandica (L.)] and gravel, together Porterinema fluviatile (Porter) Wrern (Ectocarpales) with the brown alga Cutleria multifida (Sm.) Grev. and the This species has been found to be very common in the inner red alga Scinaia pseudocrispa. The plants reach maximum part of the river mouth of the river Nordre Alv, in the size, 1 50-250 mm, in the beginning of September. Unilocular Goteborg area (Kuylenstierna1 990). It occurs in salt marshes, sporangia have been found from the middle of July until on stones and as an epiphyte and endophyte on various plants disappear at the end of October. Plants grow solitarily phanerogames, green, and bluegreen algae, and as a fouling at depths between 8 and 18 m, and they are oftenent angled organism on yachts. In more marine habitats it is found near with surrounding algae or debris. trickling freshwater (Kuylenstierna 1990). P.fluviatile has S. pedunculatus has been reported a few times earlier in been recorded throughout the year, except in January and in Sweden; in the Vadero area (Ekman 1857), in the KMBS

Acta Phytogeogr. Suec. 78 Contributions to the seaweed flora of Sweden 57

area (Kylin 1922, Wrern 1958), and it was found in the and entangled with S. arctica (Wrern 1952, Wallentinus Koster area in September 1972 (herb. I. Wallentinus). In 1979). In Norway, S. plumigera was only recorded from the Denmark records are reported from the northwestern part of Oslofjord (Sundene 1953), but it seems to occur in almost the Kattegat and from the North Sea (Ro envinge & Lund all Danish waters (Christensen et al. 1985). 1943). Printz (1952) reported one find from the Norwegian Skagerrak coast. Dictyota dichotoma (Huds.) Lamour. (Dictyotales) - In August 1991 this brown alga was found in the southern part Arthrocladia villosa (Huds.) Duby. (Desmarestiale ) - of the Vadero area. It grew in abundant mats as understorey A. villosa was found in August 1991 at two localities in the to Laminaria saccharina (L.) Lamour. on bedrock within a SW Koster area. The specimens grew at depths between 18 rather narrow depth interval between 14 and 16 m at the and 25 m, mainly on gravel composed of shells and calcified moderately exposed eastern side of the archipelago. This tubes of polychaete worm . A few specimens were found on flattened and dichotomously branched brown alga was pre­ plain rock at a depth of25 m. Plants arose as single individu­ viously observed only sporadically in Sweden (Areschoug als from small basal discoid holdfasts, although often gath­ 1850, Kylin 1947, Wrern 1958, T. Wennberg per . comm.). ered on the same piece of substrate. The sparsely branched The reports all deal with specimens found below 10 m, as main axis ranged between 20 and 150 mm. The thallus is opposed to Danish (Lund 1950) and Norwegian (Rueness much more firm than that of the closely resembling species 1977) findings, which cover abundant growth in the fucoid Sporochnus pedunculatus, which results in a more upright zone. Considerable temporal variation in occurrence is re­ position in the field. Unilocular sporangia were born at the ported in Norway (Rueness 1977). bases and lower parts of the whorl branches on the main branch system. *Sargassum muticum (Yendo) Fensh. (Fucales) - Since A. villosa is considered as one of the most rare brown 1985 the Japanese brown alga Sargassum muticum has algae on the Swedish west coast, with only a few previous regularly been found on the Swedish west coast as drift, and registrations (Kylin 1933, Wrern 1958). From Denmark, since 1987 also attached (Karlsson 1988). Still, attached Rosenvinge & Lund ( 1943) listed six findings from the NW population seem to be restricted to the northern part of the Kattegat, mainly at the same depth intervals and on the same west coast, although drifting algae have been recorded as far type of substrate as in Sweden. More recently it has been south as Laholmsbukten (Fig. 1). Although found attached recorded on three occasions between 1971 and 1977 in the in Denmark in 1984 (Christensen 1984) and as drift in same area (T. Christensen pers. comm.). Norway the same year (Rueness 1985), drifting S. muticum was first confirmed in Sweden in 1985, and the drift contin­ Sphacelaria arctica Harv. (Sphacelariales) - This species ued during the two following summers. In 1987 two at­ ha been found to be common in the inner part of the estuary tached populations were found in sheltered conditions in the of the river Nordre Alv, the Goteborg area, at depths be­ Koster area, at depths between 1 and 3 m (Karlsson 1988). tween 0.5 and 10 m, with dense mats at ea. 2 m depth By August all plants were fertile, reaching a maximum (Kuylenstierna 1990). A few individual carrying unilocular length of 180 cm. Both populations found in 1987 survived or plurilocular sporangia have been recorded in spring. the following winter, with a fivefold increase in population Plants from the estuary closely resembled specimens from numbers. During 1988 drift continued with a massive input the Baltic Sea, where the species is very common, occurring during the second half of July, which was recorded from the from the eulittoral down to a depth of at least 22 m (e.g. Goteborg area in the south to the Norwegian border in the Wrern 1952). S. arctica was previously recorded in the north, and was seen even in the innermost sheltered areas. KMBS area by Wrern (1958) and at a few other localities Two new populations were found in 1988, one in the Koster along the west coast by Prud'homme van Reine ( 1982), who area where plants were found at depths between 0.5 and 7 m, also discussed the variation in morphology exhibited by this and one in the Vadero area. The former population had, species. judging from a massive occurrence of thousands of adult individuals, probably existed for some years. During the Sp hacelaria plumigera Holm. (Sphacelariales) - In Au­ winter 1988/89 the water temperature did not fall below gust 1979 sterile, up to 60 mm high plants of S. plumigera 3.5 oc in the Koster area (Fig. 3), and previously recorded were collected at 10 m depth in two different localities in populations flourished. During 1989, a total of 38 new the Goteborg area (Kuylenstierna 1990). They were found localities were reported between the Koster and KMBS growing on boulders together with S. plumosa from which areas, the majority of them in the Koster area. Drift material S. plumigera could be difficult to separate when worn. was frequently found from March until September in the Previous records of S. plumigera on the Swedish west coast whole area. The winter of 1989/90 was again very mild, are from the Kattegat (Wrern 1945, 1964), the KMBS area resulting in relatively high water temperatures (Fig. 3). (Wrern 1958, Prud'homme van Reine 1982), and from the Following the reproductive period in 1989 the species also Koster area (August 1978, I. Wallentinus pers. comm.). In colonized open bays and basins in more exposed habitats, the Baltic, S. plumigera has been recorded as loose-lying not only rock pools and other sheltered habitats. Plants with

Acta Phytogeogr. Suec. 78 58 J. Karlsson et al.

20 -

16- () 0

m1� 2 ::::J � - Ci5 s a. E Cl) 4-...... 4 oc �

0 C\1 1.0 <0 CO 0') 0 T'"" CO CO CO CO CO CO 0') Year 0') 0') 0') 0') 0') 0') 0') �

Fig. 3. Monthly means of surface water temperature at the Tj arno Marine Biological Laboratory 1980- 1991, based on daily measurements.

a length of 250-300 cm were frequently observed. *Rhodella cf. maculata Evans (Porphyridiales) was ob­ At present (November 1991) attached S. muticum has served in samples from rock pools and shallow-water edi­ been found along the whole Swedish Skagerrak coast down ments from September 1976 and later on in the Goteborg to the southwestern part of the Goteborg area, the N Kattegat area (Kuylenstierna 1 990). The genus Rhode/la differs from (Fig. 1). It has slowly started to become a nuisance to local the well-known Porphyridium largely in ultrastructural fishery, although it is not a major problem. In Norway characteristics (Evans 1970). The Swedish material i re­ S. muticum is found attached along the whole Skagerrak ferred to a Rhodella mainly because of the den ely branched coa t (Rueness 1990). Danjsh records still cover finds from chloroplast, which is stellate in Porphyridium and due to the the Limfjorden and the west coast only (Chri tensen 1984). pinkish-brown colour. Unfortunately the off-shoot of the nucleus again t the pyrenoid (Fre nel & Billard 1987, Fig. 6A), which i typical for R. maculata, was not clearly seen Ulvophyceae during TEM observations. The genus Rhodella eems to exclu ively encompass marine and brackish water species, *Protomonostroma undulatum (Wittr.) Vinogr. (Ulvales) while at least one species of Porphyridium [P. purpureum -In May 1977, some year after the first find in Denmark (Bory) Drew & Ross] occurs both in seawater and in fresh­ (Moestrup et al. 1975), this northern species was also ob­ water habitats (Moestrup et al. 1975). R. maculata is known served for the first time in the western part of the Goteborg from adjacent Norwegian waters (Paasche & Throndsen area, growing on Polysiphonia elongata at an exposed 1970). locality at 0.5 m depth (Kuylenstierna 1990). The plants reached sizes of 80- 100 mm. It now seems to occur regu­ Hymenoclonium cf. serpens (Crouan frat.) Batters was re­ larly at exposed sites in the Goteborg and KMBS areas corded from exposed localities in the Vadero and Koster during spring (Jenneborg 1986, Kuylenstierna 1990, I. areas from the end of July to December during 1990 and Wallentinus pers. comm.). 1991, forrillng small patches, up to 15 mm wide, on various kinds of living substrata at depths between 15 and 30 m. The patches consisted of packed uniseriate filaments, often with Some additional observations opposite branching. A conspicuous secretory cell could be seen at each vegetative cell, not between adjacent cells as in In addition to the njne species listed above as new finds from the Trailliella-phase of Bonnemaisonia hamifera Hariot. the Swedish west coast we would like to mention the Various red algae have been claimed to have a presence of two small red algae of uncertain taxonomic Hymenoclonium stage in their life hjstory, Bonnemaisonia status; one fitting the description of Hymenoclonium cf. asparagoides (Woodw.) C. Ag. being the most accepted serpens (Crouan frat.) Batters, the other one referred to as (Dixon & lrvine 1977, Rueness & Asen 1982). B. aspa­ the unicellular species Rhodella cf. maculata Evans. ragoides is common on the Swedish west coast during summer and occurs at the same depth as H. cf. serpens.

Acta Phytogeogr. Suec. 78 Contributions to the seaweed flora of Sweden 59

Crusts referred to as H. serpens have previously been re­ Bucher 1977), Schmitzia vs Calosiphonia (Hawkes 1982) corded in Sweden from the KMBS area by Wrern in the and as in the case ofthe tate of sex in Dudresnaya verticillata; 1950s (M. Wrern pers. comm.). Similar crusts have also monoicism being reported by Littler (1974) and Irvine been recorded from southern Norway (Asen 1980, Rueness (1983); dioicism by Kylin (1928), Sundene (1953) and & Asen 1982). A thana iadis ( 1987), while Robins & Kraft (1985) did not discuss this question at all in their review of the genus. In Sweden, D. verticillata has been confused with Schmitzia neapolitana, as pointed out by Wrern (1961), although the latter species is monoicious. Discussion Although surveys are few, temporal variation in re ponse to more favourable years must be considered when trying to Only a few reports of marine algae new or rare to the explain the infrequent records of some of the specie on the Swedish west coa t have been published since Kylin (1944, Swedish west coast. Many of the species fo und in the 194 7, 1949) presented his data on the algal flora of this area. Vadero and Koster areas are probably at their northern limit Mo t of the additions, a well as Kylin's own work, are of distribution with respect to daylength and temperature. based on dredging (Sune on 1944, 1953, 1958, Levring Temperature conditions on the west coast depend largely on 1946, Wrem 1958, 1961, 1964, Soderstrom 1959), the only the stability of the halocline, which raises surface tempera­ exception being Wallentinus ( 1 972), who used the SCUBA­ tures during summer and lowers them during winter. It is not technique. unusual to find a stable halocline at about 10-15 m resulting Among the records accounted for in this paper, the red in surface temperatures of 18-20 oc during summer (Fig. 3) algae Platoma bairdii, Schmitzia hiscockiana, Sphaero­ with maxima of 25 oc for shorter periods, although in the coccus coronopifolius, Cryptopleura ramosa, and Hypoglos­ summers of 1989 to 1991, temperatures of 18 oc were sum hypoglossoides, the brown algae Delamarea attenuata frequently recorded at a depth of 30 m in the Koster area (B. and Sargassum muticum, and the green alga Protomono­ Rex pers. comm.). During winter, the temperature is often stroma undulatum represent additions to the Swedish sea­ very low (Fig. 3), and in 25-35% of the years there is an ice weed flora. cover along the coast. The effects of ice-scouring may be For ome of the algae the reason for the increasing amount severe for the littoral pecies, and it has been shown that of records from the Swedi h west coast is quite obvious: more than 50% of the biomass in a population of Asco­ they are recent introductions that have not yet reached their phyllum nodosum (L.) Le Jol. may be removed during a di tributional limits. This is true for the brown algae severe winter, with great impact on the population dynamics Sargassum muticum and Colpomenia peregrina. Other spe­ (Aberg 1992a, b). Except for some of the specie reported cies introduced during this century are Codium fragile from the Goteborg area, most of the species discussed could (Sur.) Hariot, Fucus evanescens C. Ag., the tetrasporophyte be included in the warm temperate Mediterranean-North of Bonnemaisonia hamifera (=Trailliella intricata Batters), Atlantic group (sensu van den Hoek 1975). Members of this of which the two latter one now occur along the entire group are characterized by a rather narrow temperature Swedish west coast, and Dasya baillouviana (Gmel.) Mont. range for optimal growth at about 15 °C, and those having a which is found from the Norwegian border to the Goteborg isomorphic life history, by having their northern distribu­ area. tion boundaries set by a lethal winter temperature (Breeman For some of the other species discussed, data on their 1988). For tetrasporophytes of Hypoglossum hypoglosso­ ecology, geographical distribution and temporal variation ides, Y arish et al. ( 1984) found a lethal temperature coincid­ are very limited. World-wide records for Platoma bairdii, ing with the 4 oc February isotherm, not allowing it to enter Schmitzia hiscockiana and S. neapolitana are few with only the eastern Skagerrak, and, correspondingly for gameto­ a few specimens found on each occasion. Records referred phytes of Cryptopleura ramosa, the 5 oc February isotherm to as P. bairdii are reported from both sides of the cold should exclude this species from the eastern part of the temperate North Atlantic region, while most of the other North Sea and the Swedish west coast (Yarish et al. 1986). representatives of the genus are reported from warm tem­ However, Breeman (1988) speculated about the existence perate or tropical regions of the northern hemisphere (Nor ris of two different populations of H. hypoglossoides with & Bucher 1977). Except for the Swedish records (Wrem different thermal preferences separated by the north Atlan­ 1961, Karlsson 1 990), Schmitzia neapolitana and S. hiscock­ tic Ocean and it should be stressed that surface temperatures iana are restricted to the Mediterranean or to NW Europe, (Fig. 3) in Sweden during winter are in general lower than but representatives of the genus are found in the Caribbean, the prevailing temperatures at the depths of 15-30 m (4- Japan, New Zealand and Australia (Wilce & Sears 1991). 10 °C, B. Rex pers. comm.), thus theoretically allowing the As a consequence of the few finds, data on morphological occurrence of both Cryptopleura and Hypoglossum. variation are scarce, which often have led to confounding Species with heteromorphic life histories often show among taxa, for example Cryptopleura vs Acrosorium more intricate combinations of light and temperature re­ (Wynne 1983, 1989) Platoma vs Nemastoma (Norris & quirements in the regulation of their life histories, which

Acta Phytogeogr. Suec. 78 60 J. Karlsson et al.

may further delimit their geographical range (Breeman still poorly known, although the knowledge of races adapted 1988). However, many algae have been shown to have the to local conditions is gradually improving (Breeman 1988, ability to propagate in different ways depending on environ­ Breeman et al. 1988). mental pressure. These features may originally have evolved The temporal occurrences of many algae along the Swed­ as means of escaping from periods of environmental haz­ ish west coast may also be regarded as a result of fluctua­ ards or from herbivory (Steams 1976). The existence of tions in the input of drifting plants, spores or sporelings alternative routes in the life histories of different from the North Sea. There is a growing knowledge of the florideophycean algae was reviewed by Maggs ( 1988), who northeastern part of the Skagerrak as a dump for wastes also showed that, for some isolates of the crustose tetra­ arriving fromthe countries fringing the North Sea (Rosenberg sporophyte of Schmitzia hiscockiana, the crust persisted et al. 1991). A continuous input probably occurs among through germination of tetraspores into new crusts. Three buoyant species such as Sargassum muticum, Colpomemia species with heteromorphic life histories were examined peregrina and many of the fucoids. The knowledge of the and in all three the tetrasporophytes dominated in abun­ dispersal range of planktonic stages in macroalgae is poor, dance over the erect gametophytes (Maggs 1988). Direct with just a few reports indicating very limited dispersal development of the gametophyte in Scinaia pseudocrispa ranges at a human time scale (van den Hoek 1987). Non­ was reported by Jones & Smith (1970), and for Bonne­ buoyant species have to rely on the huge amount of debris maisonia asparagoides by Rueness & Asen ( 1 982). Thus, it floating around in the sea, eventually ending up at a Swedish is probable that several of the species new to Sweden have shore, or on vessels as carrying vectors. The brown alga long persisted as crusts or filaments in crevices making Alaria esculenta (L.) Grev. which normally occurs along them difficult to detect. Of the species treated in this study, most of the open coasts of the North Sea, was transplanted heteromorphic life histories are reported or believed to to the Oslofjord, southern Norway, close to the Koster area occur in Schmitzia hiscockiana (Maggs & Guiry 1985), by Sundene (1962). He concluded the 16 oc August iso­ S. neapolitana (Feldmann 1954), Sphaerococcus corono­ therm to be a lethal boundary for this species. If the zoids of pifolius (Maggs & Guiry 1982b), Halarachnion ligulatum A. esculenta had possessed long range dispersal capabili­ (Boillot 1972), Scinaia pseudocrispa (Boillot 1968, 1969), ties, this species might reasonably have been a member of Arthrocladia villosa (Miiller & Meel 1982), Sporochnus the Swedish marine flora as an annual. pedunculatus (Sauvageau 1931) and in Colpomenia The occurrences of the new or the species previously peregrina (Fletcher 1987), all of which are more or less considered as rare in Sweden should be viewed in the light frequent in the British Isles (Dixon & Irvine 1977, Irvine of the discussion above. Most of them are probably genuine 1 983, Hiscock & Maggs 1 984, Maggs & Guiry 1 985, Fletcher members of the Swedish flora persisting as cryptic stages or 1987). Tetrasporogenesis as well as initial growth in as crusts over long time periods, producing erect thalli in Schmitzia hiscockiana requires short-day conditions, but a response to favourable conditions. Intensified sampling of switch to long day and high temperature is required to their habitats will probably add more true marine species to complete gametophyte growth and to induce fertility (Maggs the Swedish algal flora and improve the knowledge of their & Guiry 1985). The same conditions have been found for ecology. the transformation of the Hymenoclonium-phase to the Bonnemaisonia asparagoides-phase (Rueness & Asen 1 982). Formation of the erect gametophyte of Sphaerococcus Acknowledgements. We would like to thank Sven Nygren coronopifo lius from tetraspores produced from the for encouraging this study, Mats Wrem, Inger Wallentinus, Haematocelis fissurata crust was achieved during long day Tore Wennberg and Bertil Rex for access to private her­ and high temperature conditions (Maggs & Guiry 1982b). baria. Bertil Rex also kindly provided data on water tem­ Bonnemaisonia hamifera occurs as tetrasporophyte at the peratures in the Koster area. We would also like to thank J an Swedish west coast and is very common. Tetraspores were Rueness and Tyge Christensen for providing information on found in 1990, but are extremely rare, and the gametophyte recent Norwegian and Danish records. We are grateful to has never been fo und. This species has been shown to Anna Lundberg for not accepting Sphaerococcus as Callo­ require a daylength less than 12 h and a temperature above phyllis, to Lars-Ove Loo, Sven-Gunnar Lunneryd, Boel 11 oc in order to produce tetras pores (Breeman et al. 1 988), Olin, and the crew at the TML for assistance with SCUBA­ conditions that are very seldom fullfi lled in the eastern part diving. Thanks are also due to 'the Monitoring Group at of the Skagerrak. The same authors also fo und implications Vaderoarna' for providing diving facilities in 1991. of differences in temperature preferences among sexes re­ sulting in temporal separation of maturity, ending up in failure to reproduce sexually (Breeman et al. 1988). The impact of relatively high winter temperatures (Fig. 3) during recent years can possibly explain the occurrences of some of the species mentioned above. The consequences of varia­ tions in light and microclimate for ontogenetic processes are

Acta Phytogeogr. Suec. 78 Contributions to the seaweed flora of Sweden 61

References Gigartinales. - British Mu eum (Natural History), London. 252 pp. Dop, A.J. 1979. Porterinema jluviatile (Porter) Wrern (Phaeo­ Aberg, P. 1992a. Size ba ed demography of the seaweed Asco­ phyceae) in the Netherland . - Acta Bot. Neerl. 28: 449-458. phyllum nodosum in stochastic environments. - Ecology 73 Edelstein, T., McLachlan, J. & Craigie, J.S. 1 967. Inve tigations of (4), in press. the marine algae of Nova Scotia II. Species of Rhodophyceae Aberg, P. 1992b. A demographic study of two populations of the new or rare to Nova Scotia. - Can. J. Bot. 45: 193-2 10. eaweed Ascophyllum nodosum. - Ecology 73 (4), in pres . Ekman, F.L. 1857. Bidrag till kannedomen af Skandinaviens Areschoug, J .E. 1 850. Phyceae candinavicae marinae.-U psaliae. havsalger. - Vidtber. Filos. Fakulteten, Upsala. 16 pp. 230 pp. Evans, L. V. 1970. Electron microscopical observations on a new Asen, P.E. 1980. A note on Chondria dasyphylla, Hymenoclonium red algal unicell, Rhodella maculata gen. nov., spec. nov. ­ serpens (Rhodophyta) and Bryopsis lyngbyei(Ch1 orophyta) in Br. Phycol. J. 5: 1-13. Norway. - Br. Phycol. J. 15: 73-55. Farlow, W.G. 1875. List of the marine algae of the United State Athanasiadis, A. 1 987. A urvey of the seaweeds of the Aegean Sea with note on new or imperfectly known species. - Proc. with taxonomic tudie on species of the tribe Antitharnniae Am. Acad. Arts Sci. 10: 351 -380. (Rhodophyta). - Ph. D. thesis, Univ. GOteborg. 174 pp. Feldmann, J. 1954. Recherches urla tructure et le developpement Baard eth, E. 1941. Scinaiafurcellata and Desmarestia ligulata in des Calosiphoniacees (Rhodophycees-Gigartinales). - Rev. Norway.- Nytt Mag. Naturvid. 82: 121-122. Gen. Bot. 61: 453-499. Baardseth, E. 1974. Cryptopleura ramosa (Huds.) Kylin ex New­ Feldmann, J. 1958. Le genre Kylinia Ro envinge (Acrochaetiale ) ton (Rhodophyceae) and Omphallophyllum ulvaceum Rosenv. et sa reproduction.- Bull. Soc. bot. Fr. 105: 493-500. (Phaeophyceae) new to Norway. - Sarsia 57: 109- 1 12. Feldmann-Mazoyer, G. 1940. Recherches sur les Cerarniacees de Batters, E.A. 1900. New or critical British marine algae. -J. Bot., la Mediterranee Occidenta1e. - Alger. 510 pp. Lond. 38: 369-379. Fletcher, R.L. 1987. Seaweeds of the British Isles. Vol. 3. Berthold, G. 1884. Die Cryptonemiaceen des Golfes von Neapel Fucophyceae (Phaeophyceae). Part 1. - British Museum und der angrenzenden Meeres-Abschnitte. - W. Engelmann, (Natural History). London. 359 pp. Leipzig. 27 pp. Foslie, M. 1905. Remarks on northern Lithothamnia.-K. Nor. Boillot, A. 1968. Sur l'exi tence d'un tetrasporophyte dans le cycle Vidensk. Selsk. Skr. 3. 138 pp. de Scinaiafurcellata (Turner) Bivona, Nemalionale . -C. r. Fresnel, J. & Billard, C. 1987. Contribution a la connaissance du hebd. Seanc. Acad. Sci., Paris, ser. D 266: 1831-1832. genre Rhodella (Porphyridiales, Rhodophyceae) - Boillot, A. 1969. Sur Jedeveloppementdes tetras pore et l'edification Cryptogamie Algol. 8: 49-60. du gametophyte chez Scinaia furcellata (Turner) Bivona, Gertz, 0. 1926. Scinaiafurcellata (Turn.) Biv. En ny representant Rhodophycees (Nemalionales). - C. r. hebd. Seanc. Acad. for Va tku tens algflora. - Bot. Not. 1926: 204. Sci., Pari , er. D 268: 273-275. Hawkes, M.W. 1982. Schmitzia evanescens p. nov. (Rhodophyta, Boillot, A. 1972. Le cycle de l'Halarachnion ligulatum (Wood­ Gigartinales). A new pecie of Calosiphoniaceae from the ward) Ktitzing (Rhodophycee, Gigartinales).- Bull. Soc. Bot. northeastern New Zealand coast. - J. Phycol. 18: 368-378. Fr. Mem. 1972: 275-29 1. Hiscock, S. & Maggs, C.A. 1984. Notes on the di tribution and Braarud, T. 1950. The immigration of Colpomenia peregrina in ecology of some new and interesting eaweeds from south­ Norwegian waters. - Blyttia 1950: 125-126. west Britain. - Br. Phycol. J. 19: 73-87. Breeman, A.M. 1988. Relative importance of temperature and lrvine, L.M. 1 983. Seaweeds ofthe British Isles. Vol. 1. Rhodophyta. other factors in determining geographic boundaries of sea­ Part 2A. Cryptonemiales (sensu stricto), Palmariales, weed : experimental and phenological evidence. - Helgol. RhodymeniaJe . - British Museum (Natural History), Lon­ Meeresunters. 42: 199-241. don. 115 pp. Breeman, A.M., Meulenhoff, E.J.S. & Guiry, M.D. 1988. Life Jenneborg, L.-H. 1977. Eurychasma-infection of marine algae. history regulation and phenology of the red alga Bonnemaisonia Changes in morphology and taxonomical consequenses. - hamifera.-Helgol. Meeresunters. 42: 535-55 1. Bot. Mar. 20: 499-507. Cabioch, J. 1969. Les fonds de maerl de la baie de Morlaix et leur Jenneborg, L.-H. 1986. Inventering av marina benthossamhallen peuplement vegetal. - Cah. Bioi. Mar. 10: 139-161. inom Goteborgs skargard. Bil. 8A.- Rapport till Lansstyrelsen Christensen, T. 1975. Annotations to a distribution survey of i Goteborgs och BohusHin. (Mimeographed.) Danish marine algae. - Bot. Tidskr. 69: 253-256. Johannesson, K. 1989. The bare zone of Swedish rocky shores: Christensen, T. 1984. Sargas otang, en ny algaeslaegt i Danmark. why is it there? - Oikos 54: 77-86. - Urt 1984: 99- 104. Jones, W.E. & Smith, R.M. 1970. The occurrence oftetraspores in Christensen, T., Koch, C. & Thomsen, H.A. 1985. Distribution of the life history of Naccaria wiggi (Turn.) Endl. - Br. Phycol. algae in Danish salt and brackish water . - Univ. Copenha­ J. 5: 91-95. gen. 64 pp. Karlsson, J. 1988. Sargassum muticum, a new member of the algal Dixon, P.S. 1963. Spondylothamnion multifidum (Huds.) Nag. in flora of the Swedish West Coast. - Sven. Bot. Tidskr. 82: 1 99- western Europe. - Br. Phycol. Bull. 2: 219-223. 205. (In Swedish with English summary.) Dixon, P.S. 1964. Taxonomic and nomenclatural notes on the Karlsson, J. 1990. On the occurrence of the genus Schmitzia Florideae IV. - Bot. Not. 1 17: 56-78. (Rhodophyta, Gigartinales) on the Swedish West Coast. - Br. Dixon, P.S. 1971. Studie of the genus Seirospora. - Botaniste Phycol. J. 25: 367-374. 54( 1 -6): 35-48. Kjellman, F.R. 1872. Bidrag till kannedomen om Skandinaviens Dixon, P.S. & lrvine, L.M. 1977. Seaweeds of the British Isles. Ectocarpeer och Tilopterideer. - Dissertation, Upsala. 112 Vol. 1. Rhodophyta. Part 1. Introduction, Nemaliales, pp.

Acta Phytogeogr. Suec. 78 62 J. Karlsson et al.

Kjellman, F.R. 1878. Uber Algenregionen und Algenformationen Mathieson, A.C., Dawes, C.J. & Humm, H.J. 1969. Contributions im ostlichen Skager Rack.- Bih. K. Sv. Vetensk Akad. Handl. to the marine algae of Newfoundland. - Rhodora 785: 1 10- 5(6): 1-36. 159. Kornmann, P. & Sahling, P. 1977. Meeresalgen von Helgoland. Moestrup, 0., Nicolaisen, 1., Nielsen, H. & Pedersen P.M. 1975. Benthi che GrUn-, Braun- und Rotalgen. - Helgol. Wi . Some new or noteworthy marine benthic algae from Denmark. Meere unter . 29: 1-289. - Bot. Tid kr. 69: 257-261. Kuckuck, P. 1912. Beitrage zur Kenntni der Meeresalgen; Ueber MUller, D.G. & Meel, H. 1982. Culture tudies on the life hi tory Platoma Bairdii (Far!.) Kck. - Wiss. Meeresunters. N. F. of Arthrocladia villosa (De mare tiale , Phaeophyceae). - Abtl. Helgoland. 5: 209-278. Br. Phycol. J. 17: 419-425. Kurogi, M. 1978. The genus Polytretus (Ectocarpaceae, brown Munda, I. 1964. A find of Sorocarpus uvaefo rmis on the we tern algae) in Japan. -J. Fac. Sci., Hokkaido Univ. Ser. 5 (11): 237- coast of Norway. - Nova Hedwigia 7: 535-536. 248. Niel en, R. 1982. Ilanddrevne alger 2. - Urt 6: 85-90. Kuylenstierna, M. 1989. Benthic Algal Vegetation in the Nordre Niel en, R. & Dahl, K. 1992. Marine algae south of the i land Atv E tuary. (Swedi h We t Coa t) Vol. 2. Plate . -Part of Vejr�, the Sam � area, Denmark.- Acta Phytogeogr. Suec. thesi . Univ. Goteborg. With 76 plates. 78: 111-1 16. Kuylenstierna M. 1990. Benthic Algal Vegetation in the Nordre Norri , J. & Bucher, E. 1977. The genus Platoma (Gigartina1e , Atv E tuary. (Swedish West Coast) Vol. 1. Text. - Part of Rhodophyta) with a de cription of P. abbottiana sp. nov. ­ Ph.D. thesis. 244 pp. (incl. Appendix) Univ. Goteborg. J. Phycol. 13: 155-162. Kylin, H. 1908. Zur Kenntnis der Algenflora der chwedi chen Paa che, E. & Throndsen, J. 1970. Rhodella maculata Evans WestkUste. - Arkiv f. Bot. 7(10): 1-10. (Rhodophyceae, Porphyridiales) isolated from the plankton of Kylin, H. 1922. Algologiska notiser fdin bohuslan ka ku ten. - the 0 to Fj ord. - Nytt Mag. Bot. 17: 209-2 12. Bot. Not. 1922: 344. Pedersen, P.M. 1974a. On the systematic position of Delamarea Kylin, H. 1928. Entwicklungsgeschichtliche F1orideen tudien. ­ attenuata (Phaeophyceae, Dictyosiphonales). - Br. Phycol. J. Acta Univ. Lund. N.F. Avd. 2. 24: 1-127. 9: 313-3 18. Kylin, H. 1933. Nagra algfynd fdinboh uslandska ku ten. - Bot. Pedersen, P.M. 1974b. The life history of Sorocarpus micromorus Not. 1933: 391 -394. (Phaeophyceae, Ectocarpaceae) in culture. - Br. Phycol. J. 9: Kylin, H. 1944. Die Rhodophyceen der schwedi chen We tkU te. 57-61. - Lunds Univ. Arsskr. N.F. Avd. 2. Bd 40: 1-104. Pedersen, P.M. 1981. Porterinema luviatile as a stage in the life f Kylin, H. 1947. Die Phaeophyceen der schwedischen Westkuste. history of Sorapion kjellmanii (Fucophyceae, Ralf iaceae). ­ - Lunds Univ. Arsskr. N.F. Avd. 2. Bd 43: 1-99. In: Levring, T. (ed.) Proc. X Intern. Seaweed Symp., Goteborg, Kylin, H. 1949. Die Chlorophyceen der schwedischen WestkUste. Sweden, Augu t 1 1-15, 1980. Walterde Gruyter & Co .. Berlin. - Lunds Univ. Ar kr. N.F. Avd. 2. Bd 45: 1-79. pp. 203-208. Levring, T. 1937. Zur Kenntnis der Algenflora der norwegischen Pedersen, P.M. 1 989. Studies on Kuckuckia spinosa (Fucophyceae, WestkUste. -Lund Univ. Arsskr. N.F. Avd. 2. Bd 33: 1-147. Sorocarpaceae): Life hi tory, temperature gradient experi­ Levring, T. 1946. Nagra hav algfynd vid den sven ka va tkusten. ment , and ynonymy. - Nord. J. Bot. 9: 443-447. - Medd. Goteborg Bot. Tradg. 16: 191-194. Printz, H. 1952. On some rare or recently immigrated marine algae Littler, M.M. 1 974. The structure and reproduction of Dudresnaya on the Norwegian coast. - Nytt Mag. Bot. 1: 135-151. lubrica sp. nov. (Rhodophyta, Dumontiaceae). - Br. Phycol. Prud'homme van Reine, W.F. 1982. A taxonomic revi ion of the J. 9: 149- 156. European Sphacelariaceae. - Leiden Bot. Ser. No. 6. Leiden Lund, S. 1942. On Colpomenia peregrina Sauv. and it occurrence Univ. Pre s. 293 pp. in Danish water .-Rep. Danish Biol. Stat. 47: 1-16. Robin , P.A. & Kraft, G.T. 1985. Morphology of the type and Lund, S. 1950. The Marine Algae of Denmark. Vol. II. Au tralian species of Dudresnaya (Dumontiaceae, Rhodo­ Phaeophyceae . IV. Sphacelariaceae, Cutleriaceae and phyta). - Phycologia 24: 1-34. Dictyotaceae. - K. Danske Vidensk. Selsk. Bioi. Skr. 6(2): 1- Rosenberg, R., Cato, 1., Forlin, L., Rodhe, J., Thun!n, A. & Grip, K. 80. 1991. Large-scale environmental effect and ecological proc­ Lunneryd, S.G. & Aberg, P. 1983. Om algvegetationen vid es e in Skagerrak-Kattegat. - Research programme for the Vaderoama. - Univ. Goteborg. 50 pp. (Mimeographed.) period 1990- 1995. Swed. Environ. Prot. Agency. Report 3922. Maggs, C. A. 1988. Intra pecific life history variability in the 79 pp. (In Swedish with English summary.) Florideophycidae (Rhodophyta). -Bot. Mar. 31: 465-490. Ro envinge, L.K. 1909- 1931. The marine algae of Denmark. Magg , C.A. & Guiry, M.D. 1982a. The taxonomy, morphology Contributions to their natural history. Vol. I. Rhodophyceae. and distribution of species of Scinaia Biv.-Bern. (Nemaliales, - K. Danske Vidensk Selsk. Skr., 7. Rrekke, Naturv. og Rhodophyta) in north-western Europe.- Nord. J. Bot. 2: 517- Math. Afd. VII, 1-4: 1-630. 523. Rosenvinge, L.K. & Lund, S. 1941. The marine algae of Denmark. Maggs, C.A. & Guiry, M.D. 1 982b. The life history ofHaematocelis Vol. II. Phaeophyceae. I. - K. Danske Vidensk. Selsk. Bioi. fissurata Crouan frat. (Rhodophyta: Sphaerococcaceae). - Skr. 1(4): 1-79. Br. Phycol. J. 17: 235. Rosenvinge, L.K. & Lund, S. 1943. The marine algae of Denmark. Magg , C.A. & Guiry, M.D. 1985. Life hi tory and reproduction of Vol. II. Phaeophyceae. II. - K. Danske Vidensk. Selsk. Biol. Schmitzia hiscockiana sp. nov. (Rhodophyta, Gigartinales) Skr. 2(6): 1-59. from the British Isles. - Phycologia 24: 297-3 10. Rosenvinge, L.K. & Lund, S. 1947. The marine algae of Denmark. Maggs, C.A. & Guiry, M.D. 1987. An Atlantic population of Pikea Vol. Il. Phaeophyceae. Ill.- K. Danske Vidensk. Selsk. Bioi. californica (Dumontiaceae, Rhodophyta). - J. Phycol. 23: Skr. 4(5): 1-99. 170- 1 76. Rueness, J. 1977. Norsk Algeflora. - Universitetsforlaget, Oslo.

Acta Phytogeogr. Suec. 78 Contributions to the seaweed flora of Sweden 63

266 pp. Sven. Bot. Tidskr. 39: 396-4 18.

Ruene s, J. 1985. Japweed - Sargassum muticum - Biological Wc:ern, M. 1952. Rocky-shore algae in the bregrund Archipelago. pollution of European waters. - Blyttia 43: 7 1 -74. (In Norwe­ -Acta Phytogeogr. Suec. 30: 1-298. gian with English summary.) Wc:ern, M. 1958. Phycological inve tigations of the Swedish West Rueness, J. 1990. Spredning av japansk drivtang (Sargassum Coast. I. Introduction and study of the Gaso shell-bottom. - muticum) tangs Skagerrakkusten. - Blyttia 48: 19. Sven. Bot. Tidskr. 52: 319-342. Rueness, J. & Asen, P.A. 1982. Field and culture observations on Wc:em,M. 1961. Tillagg till Sveriges rodalgsflora. - Sven. Bot. the life history of Bonnemaisonia asparagoides (Woodw.) Tidskr. 55: 234-236. C. Ag. (Rhodophyta) from Norway. -Bot. Mar. 25: 577-587. Wc:em, M. 1964. Algal growth on a peat-bottom in Laholm Bay, Ruene s, J., Jacobsen, T. & A en, P.A. 1990. Seaweed distribution West Coast of Sweden. - Sven. Bot. Tidskr. 58: 309-3 14. (In along the Norwegian coast with special reference to Ceramium Swedish with English summary.) shuttleworthianum (Rhodophyta). - Blyttia 48: 21-26. (In Wallentinus, I. 1972. Some rare algae from the Swedish West Norwegian with English ummary.) Coast. - Sven. Bot. Tidskr. 66: 132- 1 38. Sauvageau, C. 1918. Sur la dissemination et la naturalisation de Wal lentinus, I. 1979. Environmental influences on benthic quelques algues marines. - Bull. Inst. Oceanogr. Monaco macrovegetation in the Trosa-Asko area, northern Baltic Pro­ 342: 1-28. per. II. The ecology of macroalgae and submersed phanerogarns. Sauvageau, C. 1931. Surquelques algues Pheosporees de Guethary - Contr. Asko Lab. Univ. Stockholm 25: 1-210. (Basses-Pyrenees). - Bull. Stn. Bioi. Arcachon 30: 1-28. Wennberg, T. 1 987. Long-term changes in the compo ition and the Schotter, G. 1968. Recherches sur les Phyllophoracees. - Bull. distribution of the macroalgal vegetation in the southernpart of Inst. Oceanogr. Monaco 67: 1-99. Laholm Bay, south-west Sweden, during the last thirty years. Soderstrom, J. 1959. A Swedish find of Antithamnion cruciatum - Nat. Swed. Environ. Prot. Agency, Report 3290. 47 pp. (In

(Ag.) Naegeli a genuina Kolderup Rosenvinge.- Bot. Mar. 1: Swedish with Engli h ummary.) 15-21. Wilce, R.T. & Sears, J.R. 1991. Schmitzia sanctae-crucis sp. nov. South, G.R., Hooper, R.G. & lrvine, L.M. 1972. The life history of (Calosiphoniaceae, Rhodophyta) and a novel nutritive devel­ Turnerellapennyi (Harv.) Schmitz. - Br. Phycol. J. 7: 22 1- opment to aid in zygote nucleus amplification. - Phycologia 233. 30: 151-169. Stearns, S.C. 1976. Life-history tactics: A review of the ideas. ­ Wynne, M.J. 1983. The current status ofgenera in the Delesseriaceae Quart. Rev. Bioi. 51: 3-47. (Rhodophyta). - Bot. Mar. 26: 437-450. Stegenga, H. & van Wissen, M.J. 1979. Remarks on the life history Wynne, M.J. 1989. Towards the resolution of taxonomic and of three acrochaetioid algae (Rhodophyta, Nemaliales). - nomenclatural problems concerning the typification of Acta Bot. Neerl. 28: 97- 1 15. Acrosorium uncinatum (Delesseriaceae: Rhodophyta). - Br. Sundene, 0. 1953. The algal vegetation of Oslofjord. - Skr. Phycol. J. 24: 245-252. Norske Vidensk.-Akad. Oslo I. Mat. 2. pp. 1-244. Yarish, C., Breeman, A.M. & van den Hoek, C. 1 984. Temperature, Sundene, 0. 1962. The implications of tran plant and culture light, and photoperiod responses of some Northeast American experiments on the growth and distribution ofA [aria esculenta. and West European endemic rhodophyte in relation to geo­ - Nytt Mag. Bot. 9: 155-174. graphic distribution. - Helgol. Meeresunters. 38: 273-304. Suneson, S. 1 939. Zur Algenflora der schwedischen Westktiste. ­ Yarish, C., Breeman, A.M. & van den Hoek, C. 1986. Survival Bot. Not. 1939: 57-64. strategies and temperature responses of seaweeds belonging to Suneson, S. 1944. Lithothamnionfornicatum Fosl. ny for Sverige. different biogeographic distribution groups. - Bot. Mar. 29: - Bot. Not. 1944: 265-269. (In Swedish with English sum­ 215-230. mary.) Sune on, S. 1953. Algforskningen pa Kristineberg . - K. Vetenskapsakad. Arsbok 1953. pp. 46 1 -478. Suneson, S. 1958. Lithothamnion calcareum vid svenska vastkus­ ten. - Bot. Not. 11: 195-199. (In Swedish with English summary.) Tittley, I., lrvine, D.E.G. & Jephson, N.A. 1976. The infralittoral marine algae of Sullan Voe, Shetland. - Trans. Bot. Soc. Edinb. 42: 397-4 19. van den Hoek, C. 1975. Phytogeographic provinces along the coasts of the northern Atlantic Ocean.- Phycologia 14: 317- 330. van den Hoek, C. 1987. The possible significance of long-range dispersal for the biogeography of seaweeds. - Helgol. Meeresunters. 41: 261 -272. von Stosch, H.A. 1964. Wirkungen von Jod und Arsenit auf Meeresalgen in Kultur.- In: Davy de Virville, A. & Feldmann, J. (eds.) Proc. Fourth Int. Seaweed Symp., Biarritz, Sept. 1961, pp. 142-150. von Wachenfeldt, T. 1975. Marine benthic algae and the environ­ ment in the bresund. I-III. -Ph.D. thesis, Univ. Lund. 328 pp. Wrern, M. 1945. Remarks on some Swedish Sphacelariaceae. -

Acta Phytogeogr. Suec. 78

Colonization and succession of macroalgae on a breakwater in Laholm Bay, a eutrophicated brackish water area (SW Sweden)

To re Wennberg

Abstract Wennberg, T. 1992. Colonization and succession of macroalgae on a breakwater in Laholm Bay, a eutrophicated brackish water area (SW Sweden) -Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-7210-078-8.

Macroalgal colonization of a new breakwater at Bastad harbour, SW Sweden, was studied for three years, and comparison were made with the algal flora on the nearby old break­ water. The breakwater was completed in April 1973 and already in July, 2.5 months later, 15 species grew on the shady, exposed northern side, but only 2 species on the sunny, sheltered southernside. Opportuni tic green algae (Enteromorpha spp.) dominated the flora, but also several delicately branched or sheet-like brown and red algae had settled, as well as three Fucus species. The cover degree was practically 100 % on both sides. In mid-August juveniles of F. vesiculosus were 2-2.5 cm high. F. evanescens and F. serratus were 5-5.5 cm long, and 10-13 cm six months after settling (end of September). During the first year altogether 21 species were found on the N side, and 6 on the S side. In 1974 several spring algae settled for the first time, and the Enteromorpha populations were not as dense and extensive as in 1 973. During the vegetation period of 1 974, altogether 34 species grew on the new breakwater: Bangiophyceae 12; Fucophyceae 9; Chlorophyceae 13, compared to 24, 12 and 18, respectively, on the old one. During 1975, Fucus vesiculosus and F. serratus were reproductive for the first time on the new breakwater, whereas F. evanescens had receptacles already in spring 1974. A well-developed algal vegetation typical for the area was reached in the supralittoral and the eulittoral in 1975, but the F. serratus belt in the sublittoral never fu lly developed. The eutrophication of Laholm Bay caused impoverishment of the flora and everal pecies common in the understorey of the F. serratus belt never colonized the new breakwater.

Keywords: Fucus; Growth rate; Kattegat; Settling; Zonation.

T. Wennberg, Department of Marine Botany, Universityof Goteborg, Car! Skottsbergs Gata 22, S-413 19 Goteborg, Sweden

Introduction & Norton 1979, Jansson et al. 1985). Only a few times have large, continuous surfaces like new breakwaters been utilized Since the 1920s several studies of macroalgal colonization (Moore 1939, Moore & Sproston 1940, Rees 1940). When of surfaces free of vegetation have been performed. Several a breakwater was built in 1973 at the Bastad harbour in of these referred to surfaces in vegetated areas, which had Laholm Bay, SW Sweden (56° 26' N 12° 50' E; Fig. 1), the been cleared from animals and plants (e.g. Bokenham 1938, opportunity was obtained to follow the macroalgal Northcraft 1948, Knight & Parke 1950, Lee 1966, Dayton colonization. Such an investigation has not been carried out 1975, Murray & Littler 1978, Niell 1979, Markham & before on the Swedish west coast. The breakwater was built Munda 1980). In other investigations panels or buoys of in connection to an older one, the vegetation of which I had different materials were exposed during periods of varying studied since the 1950s. My intention was to follow the length (e.g. Wilson 1925, Lund 1936, Luther 1976, Hruby colonization to the stage, when the vegetation on the new

Acta Phytogeogr. Suec. 78 66 T. Wennberg

we tern side more expo ed to waves than the eastern ide. The breakwater rests on the gently sloping sand bottom and in 1973 the depth at the outer end was 2.7 m. Henceforth, this breakwater is referred to as 'the old breakwater'. In December 1972 the con truction of a new breakwater was tarted, perpendicular to the old breakwater (Fig. 1, Plate 1). The underwater part wa ready at the end of February 1973, and on April 20 the breakwater was completed. Thi breakwater, henceforth called 'the new breakwater', was built of large boulders of red gneiss from a quarry on the nearby ridge of Hallandsas. Like the old breakwater it rests on the and bottom and the slopes of the sides are ea. 41 o. Laholm Bay The new breakwater is 10 m wide at the base and 3 m at the top, which is 2 m above the mean water level. It is 90 m long and the northern ide (N side) particularly the outer part, is moderately exposed to waves, whereas the southern side (S

Hovs Hallar side) i sheltered. In 1973 the water depth at the end wa 2 m and near the old breakwater 1.2 m. If the submersed Hallands dero surface had been smooth, it would have been 190 m2 on )S each side and 16 m2 at the end. There are, however, con iderable irregularities and large openings between the boulder , o it is realistic to increase the surface by at lea t 2 Skm 20 m on each side. On both side of the breakwaters only so· pure and bottom and beache occur, but in the hallow water 300 m from the harbour several large boulders, covered Fig. 1. Map of the study area. with seaweeds, reach the water surface.

Hydrography breakwater would be similar to that of the old one. Salinity When the investigation started in 1973, people were not Mea urements of salinity and temperature of the surface aware of the eutrophication in Laholm Bay and the impact it water were made every second day in 1966 at the outer part had. However, already in the summer of 197 4, large m as se of the old breakwater (Fig. 2). From these measurements of green algae, above all Cladophora glomerata, were and several shorter ampling period the fo llowing years, it washed ashore along the flat, unprotected beaches of the i evident that Laholm Bay i a bracki h water area with Laholm Bay, and thi phenomenon repeated itself for sev­ con iderable day-to-day fluctuations in surface water salinity eral ummers. The e and other alarming events in the mid- - during the winter months mo tly between 18 and 23 1970s marked the tart of an intensive research activity to o/co, and during April-October between 11 and 19 with lowe t find the cause of the eutrophication, different method to %o sa1inities always from May to September (cf. also Sundberg counteract it and to determine the effects on plants and & Rydberg 1986). animals (e.g. Fleischer et al. 1978, 1985, Edler 1986, Stibe & Fleischer 1986, Sundberg & Rydberg 1986, Rosenberg & Temperature Loo 1988 Rosenberg et al. 1990, Baden et al. 1990, Ryd­ The water temperature during January-March i often so berg et al. 1990). The eutrophication effects on the macro­ low that ice occurs along the shores and some winters can algae on the old breakwater were first observed in 1974 and be so cold that the entire bay is covered with thick ice. 1975 (Wennberg 1987) by a gradual elimination of some However, other winters are so warm that the ]owe t surface species; simultaneously opportunistic green and brown al­ water temperature is ea. 2-3 The latter was for instance gae increased. oc. the case in the winter of 197211973. The mean values (Fig. 2) for June-August 1966 (16.4, 18.1 and 17.9 °C, respectively) are representative for the ummer temperatures Study area of the urface water in the inner part of Laholm Bay, although the mean values have been exceeded by more than In 1930 a 150 m long breakwater was built at Bastad 1 oc during several summer . harbour, consisting of large boulders taken from the bottom of Laholm Bay (Fig. 1). It stretches from south to north; the

Acta Phytogeogr. Suec. 78 Colonization and succession of macroalgae 67

� Temperature oc -+- Salinity %o Results

20 22 The old breakwater 21

15 20 On the old breakwater there is always a dense belt (0.2-0.3

19 m broad) of the barnacle Semiba/anus balanoide (L.) [ = Balanus balanoides(L.)]. On the E side, the harp upper 10 18 limit of the belt coincided exactly with the mean water 17 level, while on the moderately exposed W side the harp 5 16 upper limit was about 3-4 cm above mean water level. The 15 upper limit of this belt, henceforth named the 0-line (zero­ 14 line), indicates the limit between the supralittoral and the -2 �,-��-r�� 13 eulittoral. The depth distribution ofthe algae wa referred to J F M A M J J A S 0 N D thi level. A Semiba/anus belt wa lacking on the new breakwater the first year , and in tead the 0-line on the E Fig. 2. Surface water salinities and temperature at the outer part of side of the old breakwater wa taken as depth marker. Other the old breakwater, Bastad harbour. Monthly means are based on animals fairly common on the breakwater were Littorina measurement made every other day in 1966. littorea (L.), Mytilus edulis L. andAsterias rubens L., while Littorina saxatilis (Olivi), Littorina obtusata (L.) and Balanus improvisus Darwin were less common. Patella vulgata L., which can strongly affect the vegetation by Transparency grazing, was never ob erved on the breakwater. As the breakwater are surrounded by pure and bottom and The macroalgae that occurred on the old breakwater, i.e. the water depth is le s than 3 m, the wave whirl up the from which the colonizers on the new breakwater were sediments already at moderate westerly winds. Under these recruited, are listed in Table 1. In the supralittoraJ green circumstances the water is like a sandy su pen ion, and the algae were predominant. Throughout the year there was a Secchi disc depth only 0.3-0.4 m. Such conditions were on belt consisting of the green algae Urospora penicillifo rmis, average prevailing for 6-8 days per month during the Ulothrixflacca, V. subflaccida and V. speciosa, varying in colonization study. height and composition with the season. In winter Prasiola stipitata and Rosenvingiella polyrhiza formed a den e popu­ Water level lation above the Urospora-Ulothrix belt at the end of the The tide i insignificant in Laholm Bay (< 10 cm). The breakwater, a ite where ea-gulls frequently rest. Near the major changes in water level are due to the wind and air 0-line Blidingia minima and Porphyra purpurea formed pressure conditions. Usually, the fl uctuations are maximally narrow belts along most of its sides. The red algae Bangia 0.2-0.3 m from one day to another, but extreme low water atropurpurea and Porphyra linearis disappeared from the levels occur during spring from March to May, when the old breakwater in 1968 and 197 6, re pecti vely. water level can be 0.5-0.6 m below mean for long periods. Acrosiphonia centralis, Sp ongomorpha aeruginosa, Monostroma grevillei, Pilayella littoralis, Scytosiphon lomentaria, Petaloniafascia, Punctariaplantaginea, Chor­ f Material and Methods daria flagelliormis, Dumontia contorta and Polysiphonia urceolata belonged to the spring flora in April - May and The algal vegetation in the eulittoral and sublittoral was covered most of the boulders in the eulittoral and the upper­ investigated with SCUBA diving every month from April most sublittoral. At periods of low water, often several days to October during three years, tarting in 1973. During the long, parts of the community were emerged and many cold season (November-March) I irregularly collected algae specimens died. In May Enteromorpha intestinalis, E. linza, with a hand scraper. For quantitative samplings frames of E. prolife ra and Cladophora glomerata developed rapidly different sizes were used. The algae were identified alive and at the beginning of 1 une they replaced parts of the spring flora and thereafter they were an important part of the and preserved (herbarium and/or 70 o/o alcohol) in Bastad and at the Department of Marine Botany, University of vegetation during summer and early autumn. Goteborg, where they also are deposited. Three Fucus species formed more or less dense and continuous belts around the old breakwater. The F. vesi­ culosus belt started 0. 1 5-0.2 m below the 0-line and reached a maximum depth of 0.5 m, where the F. serratus belt began. This limit forms the border between the eulittoral and the sublittoral. The F. serratus belt continued down to the sand bottom along most of the breakwater, but in places

Acta Phytogeogr. Suec. 78 68 T. Wennberg

Bangiophyceae Ahnfe ltia plicata (Huds.) Fries Ectocarpus siliculosus (Dillw.) Lyngb. Audouinella purpurea (Lightf.) Woelk. Elachista fucicola (Yell.) Aresch. Cal/ithamnion corymbosu.m (Sm.) Lyngb. Fucus evanescens C. Ag. Ceramium rubrum (Huds.) C. Ag. Fucus serratus L. Ceramium strictum Harv. Fucus vesiculosus L. Chromastrum kylinoides (Feldm.) Stegenga et van Wissen Petaloniafascia (0. F. MUll.) Kuntze Chromastrum virgatulum (Harv.) Papenf. Pilayella littoralis (L.) Kjellm. Chondrus crispus Stackh. Punctaria plantaginea (Roth) Grev. Cystocloniwn purpureum (Huds.) Batt. Scytosiphon lomenraria (Lyngb.) Link Dumontia contorta (Gmel.) Rupr. Sphace/aria cirrosa. (Roth) C. Ag. Erythrotrichia carnea (Dillw.) J. Ag. Furcellaria. lumbricalis (Huds.) Lamour. Chlorophyceae Hildenbrandia. rubra (Sommerf.) Menegh. Acrosiphonia centralis (Lyngb.) Kjellm. Phycodrys rubens (L.) Batt. 8/idingia minima (KUtz.) Kylin Phyllophora. pseudoceranoides (Gmel.) Newroth & Taylor Chaetomorpha melagonium (Web. & Mohr) KUtz. Phyllophora truncata (Pallas) Zinova Cladophora jlexuosa (MUll.) KUtz. Phyma.tolithon lenormandii (Are eh.) Adey Cladophora glomerata (L.) KUtz. Polyides rotundus (Hud .) Grev. Cladophora hamosa KUtz. Polysiphonia elongata (Huds.) Spreng. Cladophora rupestris (L.) KUtz. Polysiphonia nigrescens (Huds.) Grev. Enteromorpha intestinalis (L.) Link Polysiphonia urceolata (Dillw.) Grev. Enteromorpha /inza (L.) J. Ag. Polysiphonia. viola.cea (Roth) Spreng. Enreromorpha prolife ra (0. F. MUll.) J. Ag. Porphyra !inearis Grev. Monostroma grevillei (Thur.) Wittr. Porphyra purpurea (Roth) C. Ag. Prasiola stipitata Suhr in Je en Rhodome/a confervoides (Huds.) Silva Rosenvingiella pofyrhiza. (Ro env.) Silva Spermothamnion repens (Dillw.) Ro env. Spongomorpha aeruginosa (L.) Hoek Ulothrixfiacca (Dillw.) Thur. in Le Jol. Fucophyceae Ulothrix speciosa (Harv.) KUtz. Chorda. tomentosa Lyngb. Ulothrix subfiaccida Wille Chordariafiagellifo rmis (0. F. MUll.) C. Ag. Urospora penicilliformis (Roth) Aresch.

near the end of the breakwater it only reached ea. 1.5 m in the water-line were not put in place until the end of below the 0-line. Between these two belt , F. evanescens February, green algae grew as soon as ix weeks later in a was growing, partly interspersed in the lower part of the F. continuou belt from 0. 15 m below the 0-line to 0.2 m above vesiculosus belt, partly in the upper part of the F. serratus it. The upper part of the belt consisted of Urospora belt, i. e. between - 0.3 and - 0.6 m. F. evanescens is an penicilliformis, Ulothrixflacca and U. pecio a ( parsely). introduced pecie in Laholm Bay with the first pecimens In the eulittoral Enteromorpha prolifera occurred in patches, recorded on the old breakwater in the spring of 1970. mo t plant were 5-6 cm high. No other macroalgae were The understorey to Fucus serratus consisted mainly of growing there. All algae had been recruited from spore perennial elements uch a the red algae Ahnfe ltia plicata, tran ported by the water. Furcellaria Lumbricalis, Phyllophora pseudoceranoides, P. truncata, Phycodrys rubens, Chondrus crispus, Polyides S side: April l5 rotundus, Rhodomela confervoides, Ceramium rubrum, No macroalgae were growing on thi side. C. strictum, Polysiphonia nigrescens, Phymatolithon lenor­ mandii and the green algae Cladophora rupestris and Chaeto­ N side: July 3 morpha melagonium. During May and June an exten ive colonization took place, particularly by rapidly growing opportunistic green aJgae, but also by a number of brown and red algae. Altogether 15 The new breakwater, 1973 species were found. However, several delicately branched or monostromatic sheet-like or tubular annual , characteri - Since the vegetation developed differently on the shady, tic of the pring flora on the old breakwater, had not been moderately exposed N side and on the sunny, sheltered S able to colonize the new breakwater, probably because of side, these are de cdbed separately. The periods during competition with the Enteromorpha species. The missing which the various pecies colonized the N side are shown in pecies compdsed Acrosiphonia centralis, Spongomorpha Figs. 3-4. aeruginosa, Monostroma grevillei, Blidingia minima, Poly­ siphonia urceolata and the coarser, tubular Scytosiphon N side: April l5 lomentaria. Zonation and degree of cover are hown in Fig. Despite large amounts of mud in the water during the 4, and summarized in the survey below. Unless otherwise construction of the breakwater, and the fact that the boulders stated, the distribution of the individual species wa similar

Acta Phytogeogr. Suec. 78 Colonization and succession of macroalgae 69

Callithamnion corymbosum Call�hamnion corymbosum Ceramium rubrum ------Ceramium rubrum ------Ceramium strictum ceramium strictum Chondrus crispus ------Chondrus crispus Hildenbrandia rubra ------Hildenbrandia rubra Phyllophora truncata ------Phyllophora truncata Polysiphonia elongata ------Polysiphonia elongata ------Polysiphonia nigrescens Polysiphonla nigrescens Polysiphonia urceolata -Polysiphonia urceolata Polysiphonia violacea - Polysiphonia vlolacea ------Porphyra purpurea Porphyra purpurea Rhodomela confervoides ------Rhodomela confervoides

Chordarla flagelllformis -Chordaria flagelliformis Ectocarpus slilculosus -Ectocarpus siliculosus Elachista fucicola -Eiachista fucicola Fucus evanescens ------Fucus evanescens Fucus serratus ------Fucus serratus ------Fucus veslculosus Fucus vesiculosus Petalonia fascia -Petalonia fascia Pilayella linoralis -Pilayella linoralis Scytosiphon lomentaria -Scytoslphon lomentaria

Acrosiphonia centralis -Acrosiphonla centralis Blidingia minima ------Biidlngia minima Chaetomorpha malagonium ------Chaetomorpha melagonium Cladophora flexuosa Cladophora flexuosa Cladophora glomerata Cladophora glomerata Enteromorpha lntestlnalis Enteromorpha intestinalis Enteromorphallnza Enteromorpha linza Enteromorpha prolifera Enteromorpha prolifera Monostromagrevillei -Monostroma grevillei Prasiola stipitata ------Prasiola stipltata Rosenvingiella polyrhlza -----Rosenvingiella polyrhiza Ulothrix fl acca --Uiothrix flacca Ulothrix subflaccida --Uiothrix subflaccida Urospora penicilliformls ------Urosporapenicilliformis

JFMAMJ JASON DJF MAM JJASON DJFMA MJ JASONDJFMA 1973 1974 1975 1976

Fig. 3. Colonization and succes ion of macroalgae, from spring 1973 to spring 1976, on the N side of the new breakwater, Bastad harbour.

all along the same side of the breakwater. Urospora penicillifo rmis and Ulothrix flacca: The same belt as in April, but U. speciosa was missing. Enteromorpha proliera:f The ame belt near the 0-line a in Urospora penicilliformis April, but now the plants were more prolific and larger. The Ulothrix flacca Enteromorpha prolifera species was also established on the boulders from - 0.5 m to Enteromorpha linza -2 m. The population in the sublittoral was very dense, and Cladophora glomerata Petalonia fascia the plants were longer (up to 0.5 m long) than in the upper Chordaria flagelliformis f Pilayella littoralis eulittoral, and corresponded to E. prolifera ssp. proliera ' ' Ectocarpus siliculosus ' Fucus spp. typus II (Bliding 1963). ' Porphyra purpurea Enteromorpha linza: Common from the 0-line to - 0.6 m, Callithamnion corymbosum 0.4m--- Ceramium strictum partly intermingled with E. prolifera. Polysiphonia nigrescens Cladophora glomerata: Scattered plants among Entero­ Polysiphonia violacea f 0-line --- morpha proliera from - 1 to - 1.5 m; the largest measuring Degree of cover (%) - 50 -100 18 cm. Normally this species mainly grows in the eulittoral 10 -50 <10 in Laholm Bay. In the Baltic Sea it can reach depths of 6-8 -0.5 m- -- m (Wrern 1952). Petaloniafascia: Fairly common between - 0. 1 to - 0.6 m. The first plants were observed at the end of May, and a -1.0 m--- month later many had a considerable length (up to 29 cm). Chordaria flagelliformis: Scattered from -0. 1 to -0.6 -1.5 m--- (-1 .0) m. Most specimens ea. 15 cm, a few 25 cm high. The first plants were observed at the end of May. _1 .8 m ___ �----=S:..:a::.:..nc::cd-=bc::co.:..:.tto:..:m::.:.. Pilayella Littoralis: Settled in May, now forming an under­ storey in the Enteromorpha belts down to -1 m. Most plants with unilocular sporangia. Fig. 4. Belt transect, 0.5 m in width, on the N side of the new Ectocarpus siliculosus: Common as understorey in the breakwater, 40 m from the end. Bastad, July 3, 1973. The circle Enteromorpha belts from -0.4 to -1.5 m, but with a indicates the vegetation thc.t wasgr owing in April on the N side.

Acta Phytogeogr. Suec. 78 70 T. Wennberg

Plate 1. Prasiola stipitata growing on the N side and the upper side of the new breakwater, especially on the rugged concrete joints between the boulders. Bastad, March 4, 1976. Photo Tore Wennberg.

Plate 2. The vegetation in the upper eulittoral on the N side of the new breakwater four months after the settling started; Enteromorpha linza, E. prolifera, Porphyra purpurea, Ceramium strictum. Bastad, August 17, 1973. Photo Tore Wennberg.

Acta Phytogeogr. Suec. 78 Colonization and succession of macroalgae 71

decreasing degree of cover below - 1 m. The plants, a few Ectocarpus siliculosus: Declining with a reduced cover. cm high, had plurilocular sporangia and agreed with Fucus vesiculosus: Juveniles (2-2.5 cm high) were growing E. confervoides (Kylin 1947, Kornmann & Sahling 1977). 0.2 m below the 0-line, hidden in the Enteromorpha carpet. A few larger pecimens were growing a epiphyte on Fucus evanescens and F. serratus: The small Fucus plants Chordaria flagellifo rmis. observed in July were now 5-5.5 cm high, several hawing Fucus spp.: Plant ea. 15 mm long, and not sufficiently their first dichotomy. developed for identification, were observed in the den e Porphyra purpurea: Still very common, many plant 15-20 Enteromorpha carpet, 0.5-0.6 m below the 0-line. cm in diameter (Plate 2). Porphyra purpurea: Common in the eulittoral; many plants Ceramium rubrum: Occurred for the first time as scattered were fertile. During June the number of indi victualsin creased plants in the sublittoral. considerably. Ceramium strictum: Explosive development since July (Plate Callithamnion corymbosum: Large plants, as epiphytes on 2). It was growing from - 0.2 m down to the sand bottom Chordariaflagellifo rmis, from - 0.5 to -1 m. Below - 1 m, with a density of25-50 specimen per m2, mostly as epiphytes the species was growing in the Enteromorpha prolifera belt on Enteromorpha linza, Cladophora glomerata, Petalonia with a density of 1-3 pecimens per m2. According to my fa scia, Pilayella littoralis and Polysiphonia nigrescens. investigations this specie has been fairly common in Laholm Parasporic, tetrasporic and sexual plants were common. Bay since the 1960s, occurring from a depth of 0.5 (1.0) m. Polysiphonia nigrescens: More common and larger than in Kylin (1944) reported it as fairly rare in the area at depths July, often with Ceramium strictum as epiphyte. between 2 and 20 m, and von Wachenfeldt (1975) reported a fe w finds of 2 cm high plants. Many specimens on the new S side: August 17 breakwater were 5-6 cm high. The vegetation was still dominated by Enteromorpha Ceramium strictum: Rare from -0.4 to -1 m, from -1 m intestinalis and E. prolife ra, but since July Ceramium down to the and bottom more common with on average strictum and Polysiphonia nigrescens had colonized. 6-7 plants per m2. Epilitic but also epiphytic on Enteromor­ pha linza and Polysiphonia nigrescens. Many plants with N side: September 30 parasporangia. The first specimens on the new breakwater Impoverishment of the summer vegetation became obvious were found at the beginning of June. during September. Cladophora glomerata, Petaloniafascia Polysiphonia nigrescens: The same depth and frequency as and Chordaria flagelliformis declined rapidly and Ceramium strictum. At the beginning of June small speci­ di appeared (Fig. 3). Ceramium strictum had decrea ed too. men were abundant, a month later most of them were 8-9 In tead the three Fucus pecies were conspicuou in the cm long. vegetation for the first time, e pecially F. evanescens and Polysiphonia violacea: Scattered plants (up to 7 cm long) F. serratus, which probably had been able to ettle on the from - 0.4 m down to the sand bottom. new breakwater already at the end of March. F. evanescens had, on the old breakwater, fu ll release of gametes from the S side: July 3 end of February to the end of May, and F. serratus had been Only two species had colonized since April, and were now fertile ince October 1972 and till relea ed gamete during covering the boulder from the 0-line down to the sand January-March 1973. The individuals of these two Fucus bottom. Enteromorpha intestinalis predominated, its degree pecies on the new breakwater were, at most, 6 months old. of cover approaching 100 %. Most plants were very long They grew together in a belt, 0.2 m broad, in the uppermo t (up to 1 .74 m). Intermingled with the E. intestinalis popula­ sublittoral; 4-6 plants of each species per metre. Thus 400- tion large specimens of Enteromorpha prolifera occurred. 450 specimens of each species had germinated and grown successfully under the Enteromorpha carpet. The large t N side: August 17 F. evanescens plants (Fig. Sa) were 13 cm long, correspon­ Since July only a few new species had colonized (Fig. 3), ding to a growth rate of 5 mm per week (if the plant were but several of the species from July had grown larger and 6 months old). Most plant were 10-1 1 cm and the average extended their cover degree (Plate 2), whereas others had weekly growth rate was thus probably slightly less than decreased. 5 mm. Several F. serratus plants were alsc 10-12 cm long Cladophora glomerata: Common, intermingled with Entero­ (Fig. 5b), and had thus a growth rate irnilar to F. evanescens. morpha prolifera below -1 m. Often with epiphytes such as On the old breakwater, F. vesiculosus released gametes Ceramium strictum, Callithamnion corymbosum, £eta­ later than the other two Fucus species (from the end of carpus siliculosus, Chromastrum virgatulum and C. kylin­ March until September). The small size of the new plants, oides. The latter epiphyte, rare on the old breakwater, was 4-6 cm long and no dichotomies, indicates that F. vesiculosus extremely common and coloured the branches of the host had settled later (ea. 4 month ago) and that the dense plants red. Enteromorpha carpet probably had a negative impact. Chordariaflagellifo rmis: Most plants 25-35 cm long. F. vesiculosus was growing in a belt 0. 1 5-0.3 m below the Petaloniafascia: Declining; only a few specimens observed. 0-line.

Acta Phytogeogr. Suec. 78 72 T. Wennbe rg

L-....1 tern b

Fig. 5. Fucus evanescens (a) and F. serratus (b). Both ea. 6 month old and together forming a narrow belt 0.5 m below the 0-line on the N ide of the new breakwater. Bastad, September 30, 1973.

Fig. 6. Fucus evanescens, about 7 months old, with six dichotomies and with Ceramium strictum as an epiphyte. The N side of the new breakwater. Bastad, October 28, 1973. Scm

Acta Phyrogeogr. Suec. 78 Colonization and succession of macroalgae 73

Other macroalgae on the N side, September 30: Urospora penicilliformis: A continuous belt, 0.4 m broad, in the supralittoral. Enteromorpha prolife ra: Declined rapidly. Enteromorpha linza: Still very common. During September it invaded the boulders in the sublittoral, that previously had been covered with E. prolifera. Porphyra purpurea: Common in a belt near the 0-line together with the blue-green algae Lyngbya lutea (C. Ag.) Gom. ex Gom. Ceramium rubru m: Scattered plants in the sublittoral; more common near the end of the breakwater. Polysiphonia nigrescens: Common in the sublittoral since mjd-August.

S side: September 30 During September a narrow Urospora penicilliformis belt had developed above the 0-line. Enteromorpha intestinalis and E. prolifera had declined. Ceramium strictum had not changed and Polysiphonia nigrescens was more common.

N side: October 28 The Lyngbya lutea belt had become broader during October, and now the species was also found in the understorey to the Enteromorpha linza population down to a depth of- 0.3 m. E. linza was common down to - 0.4 m, but deeper down it had decreased. All the Fucus species had grown 1-2 cm and particularly the plants of F. evanescens were much ramified with as many as 6 dichotomies (Fig. 6). On most of the latter Ceramium strictum was growing at the base; also C. rub rum was common a an epiphyte. These two Ceramium species were al o growing on horizontal boulder urface , at 0.3-0.4 m depth, together with Pilayella littoralis, Callithamnion corymbosum and Petalonia fa scia. The latter had been Fig. 7. Fucus vesiculosus, 6-6,5 months old and maximaJiy 10 cm missing since the end of August, but occurred now again in long, formed a belt from 0.2 m below the 0-line on the N side of the small clusters of 2- 17 cm long plants. new breakwater. Bastad, December I, l973. The scale bar is 5 cm.

S side: October 28 Only Ceramium strictum, Polysiphonia nigrescens and a few C. rub rum and Enteromorpha intestinalis were growing on the boulders. The new breakwater, 1974

N side: December 1 After a mild winter without ice, all species that occurred on Below the 0.5 m broad Urospora penicillifo rmis belt, December 1, 1973 had survived (Fig. 3). Several Fucus Porphyra purpurea and Fucus vesiculosus grew in the evanescens plants (13-15 cm) carried receptacles with ma­ upper eulittoral. The Fucus plants, maximally 6.5 months ture antheridia and oogonia in March. Already in February, old, were 5-10 cm long (Fig. 7). The vegetation in the patches with Prasiola stipitata occurred more than 1 m sublittoral consisted of F. evanescens and F. serratus in a above the 0-line on the end of the breakwater (cf. Plate 1). 0.2 m broad belt from -0.5 to - 0.7 m and Ceramium During the spring months of 1974 some species, which strictum, C. rubrum and Polysiphonia nigrescens from were part of the spring flora of the old breakwater, settled for - 0.4 m down to the sand bottom. the first time on the new breakwater. Thus Monostroma By the end of the first year altogether 21 macroalgal grevillei, Acrosiphonia centralis, Pilayella littoralis and species had been found on the N side (Fig. 3) and 6 species Polysiphonia urceolata were found in April and May on the S side. (Fig. 3). They were so common on the N side of the breakwater, that they formed a continuous belt in the eulittoral from - 0.2 m. A. centralis and P. littoralis also reached

Acta Phytogeogr. Suec. 78 74 T. Wennberg

eulittoral during the latter part of May, as had been the ea e every year on the old breakwater. This spring, C. glomerata also ettled on the S side of the new breakwater, but to a lesser extent than on the N side. The red algae Ceramium rubrum, C. strictum and Poly­ siphonia nigrescens, already well-established since the pre­ vious year, increased rapidly during pring and early sum­ mer. Thi particularly applied to C. rubrum, which this summer also was common as an epiphyte on Fucus serratus. P. nigrescens mainly grew on the boulder below the F. serratus belt, where Enteromorpha prolifera, o com­ mon here the previous ummer, now grew spar ely. Instead P. nigrescens competed for pace with Cladophora flexu­ osa, a new settler (Fig. 3). The latter pecies wa common in the sublittoral on the old breakwater and often occurred unattached in large quantities on the sand bottom. Below F. serratus, Chaetomorpha melagonium was found parsely for the first time (Fig. 3), scattered along the breakwater. On the N side of the breakwater again a11 three Fucus E species reestablished during spring and early summer. In (,)

If) July many juveniles were ob erved, and in Augu t and September it was evident that F. evanescens had been most succe sful, with many pecimens in a belt below F. vesi­ culosus. For the first time F. evanescens also grew on the S side in a narrow belt 0.3 m below the 0-Iine. Since the Fucus vegetation now was abundant, the epiphyte Elachistafucicola Fig. 8. Fucus vesiculosus, about 1 year old, with the first air was found in July (Fig. 3) on the one-year-old F. serratus ve icles. The N side of the new breakwater. Ba tad, May 8, 1974. plants. Of all perennial red algae in the F. serratus belt on the old breakwater, apart from Ceramium rubrum, C. strictum and about 0.3 m below the narrow Fucus serratus belt. Addi­ Polysiphonia nigrescens (which already settled in 1 973), tionally, Scytosiphon lomentaria and Petaloniafascia grew only Chondrus crispus and Phyllophora truncata ettled on in small clusters just below the 0-line, S. lomentaria being a the new breakwater in 1974 (Fig. 3). A small specimen of new colonizer. At the end of May also Chordaria C. crispus wa found at the end of the breakwater and 11 flagellifo rmis reappeared (Fig. 3). small Phyllophora truncata grew 0.7 m below the 0-line. On the S side of the breakwater, where few species had Hildenbrandia rubra was the only crustose colonizer and colonized the first year, both Monostromagrevillei, Pilayella covered the boulders around the 0-line during the latter part littoralis and Polysiphonia urceolata settled for the first of 1974, wherea Phymatolithon lenormandii never settled time during the second spring. P. urceolata formed large, on the new breakwater. The latter, which grew in the Fucus bright to dark wine-red balls, which through the water serratus belt on the old breakwater, decreased during the looked like sea-urchins against the partly naked boulders. end of the 1970s, a a result of extensive Mytilus beds and On the other hand, spring algae, such a Spongomorpha increa ed eutrophication, and is no longer growing there aeruginosa, Punctaria plantaginea and Dumontia contorta (Wennberg pers. obs.). did not settle on the new breakwater. Of these at least Three of the animal living on the old breakwater were P. plantaginea and D. contorta suffered from stress in the fo und on the new one in the ummer of 1974, viz. eutrophicated environment. 1975 wa the last year Semibalanus balanoides which releases its larvae in April, D. contorta grew on the old breakwater and a few years later Mytilus edulis with settling in June and Littorina littorea, al o P. plantaginea disappeared. They have never returned which probably had migrated as adults from the old break­ to the breakwaters (Wennberg 1987, Wennberg pers. obs.). water. All three occmTed in small numbers and their pres­ After the decline of the spring algae, Enteromorpha ence probably had not influenced the vegetation. proliera,f E. linza and E. intestinalis returned.The popula­ During the growing season of 1974, i. e. 1-1.5 years after tions, however, were not a dense and extensive in 1974 the new breakwater was completed, altogether 34 different because Fucus vesiculosus occupied part of the eulittoral. specie grew on it: Bangiophyceae: 12 species (24 on the old The Fucus plants were now one year old with the first air breakwater); Fucophyceae: 9 specie (12); Chlorophyceae: vesicles formed (Fig. 8). Furthermore, Cladophora 13 species (18). Altogether 34 macroalgal species had been glornerata had rapidly developed a large population in the found on the N side (Fig. 3) and 12 species on the S side. Of

Acta Phytogeogr. Suec. 78 Colonization and succession of macroalgae 75

the 34 species 16 overwintered and were ob erved when the third growing season started.

The new breakwater, 1975

During winter the green algal population in the upralittoral increased still more. This was particularly obvious for Prasiola stipitata, which covered most of the boulders along the outer part of the N ide, from 2 m above the 0 line down to the upper limit of the Urospora-Ulothrix belt. Furthermore, Rosenvingiella polyrhiza grew on the upper ide near the end of the breakwater, and wa particularly abundant in February and March. As many ea-gulls re ted on the new breakwater, nitrophilous species such as Prasiola stipitata were fa­ voured. Already one year later, in March 1976, it grew not only on the N side of the breakwater but also on large parts of the horizontal upper side, above all on the rugged con­ crete joints between the boulders (Plate 1). From the end of March the same spring flora returned as in 1974, but now it had less pace at its dispo al in Fig. 9. Chondrus crispus f. abbreviata Kj ellm. Several mall plants competition with Fucus vesiculosus and F. evanescens. grew in the ublittoral on the N ide of the new breakwater, two Scytosiphon lomentaria was more common in 1975, and years after it was completed. Bastad, July 4, 1975. then it also grew on the S side in spring, together with Petaloniafascia and Porphyra purpurea. For the first time Blidingia minima was part of the vegetation on the N side (Fig. 3), forming a narrow belt around the 0-line. This was a surprisingly late colonization, a it grew every year on the old breakwater. During summer B. minima declined con id­ During 1975 the belt of Semibalanus balanoides became erably, but it increased again in autumn. con iderably denser on the new breakwater, the number of The plant of Fucus vesiculosus and F. serratus which Littorina littorea increa ed, and above all Mytilus edulis had settled during spring and early summer in 1973 repro­ was settling densely both on the boulders and on many duced in 1975. F. vesiculosus had receptacles in March and seaweeds. By the end of the third year altogether 38 released gametes from April, while F. serratus receptacles macroalgal species had been found on the N side and 17 were common for the first time in October 1975. This year species on the S side. F. vesiculosus al o settled for the first time on the S side, where small plants were ob erved in the summer together with F. evanescens, which had grown there since the previ­ Discussion ous summer. F. serratus on the other hand, never settled on the S side of the breakwater, nor was a broad belt developed This investigation of algal colonization on a large intro­ down to the sand bottom on the N side (contrary to the ea e duced substratum confirms earlier observations that ephem­ the old breakwater). eral, opportunistic algae (mostly green algae), are the first Several small Chondrus crisp us plant were discovered in colonizers. They were, however, oon followed by other ummer 1975 on the N side (Fig. 9) and Phyllophora immigrants, also perennial ones, when viable settling cells truncata was more common than before. Two other peren­ were available. Almost all algae, growing on the new break­ nial species, growing in the subli ttoral on the old breakwa­ water in the first year, were filamentous, delicately branched, ter, Rhodomela confervoides and Polysiphonia elongata or sheet-like or tubular form . The species composition appeared sparsely on the new one (Fig. 3). P. elongata, resembled that of a recolonization study in the rocky eulittoral including f. lyngbyei (Kylin 1 944), grows much closer to the at Helgoland (Markham & Munda 1 980). W allentinus ( 1 984) urface in Laholm Bay than reported by Kylin ( 1944) for the showed that algae with these morphologies have faster Swedish west coast, and for the Oresund by von Wachenfeldt uptake rates of nitrogen and phosphorus than others, which (1975). At Hovs Hallar (Laholm Bay) it is common from ha implications for the competitive outcome in nutrient­ -0.3 m, and on the new breakwater it was growing only 0.8 enriched environments like Laholm Bay. Rosenberg & m below the 0-line. Ramus ( 1982) concluded that fast nitrogen uptake rates may be necessary for the strategy of the opportunistic macroalgae,

Acta Phytogeogr. Suec. 78 76 T. Wennberg

and that this fast uptake ha to be fo llowed by a rapid growth though they were fairly common on the old one until the in order to avoid los es of their nitrogen-rich tissues through mid- 1 970s, e.g. Furcellaria lumbricalis, Poly ides rotundus, e.g. grazing and abra ion by wave action. Phyllophora pseudoceranoides, Phycodrys rubens, This investigation also show how expo ure and location Cladophora rupestris, Spongomorpha aeruginosa. On the affect the diversity of the settled flora. Although the dis­ old breakwater S. aeruginosa was only growing in the tance to the almost uniform flora of the old breakwater was sublittoral, mainly a an epiphyte on Ceramium rubrum. the same, after four month only two specie were growing On the S side the community only comprised a few on the unny, sheltered S ide of the new breakwater, while specie , probably reflecting the environmental condition 15 had colonized the shady, wave expo ed N side. The on this sunny and sheltered side. In the summer of 1976 the degree of cover wa practically 100 % on both side . The vegetation on the S side was similar to that on the E ide of number of species increased throughout the uccession, the old breakwater south of the new one, where impoverish­ although the number varied with the season also (Fig. 3). ment and alteration of the flora had occurred after the new Still after three years there were significantly fewer species breakwater was built. on the S side, and only two pecies were considerably more It i evident that colonization by macroalgae i mainly due common there, viz. Enteromorpha intestinalis and to the ea onally varying spore bank and to space available Polysiphonia urceolata. for porelings. The succession is then determined by the life Thalli developing from spores which became attached history of the different species, interspecific competition above or below the normal vertical range of the species in and their relation to abiotic factors (cf. e.g. Jansson et al. question, ultimately disappeared. Examples are Entero­ 1985). morphaprolifera, E. linza and Cladophora glomerata, which During the latter part of the 1970s and during the 1980s, during the fir t summer grew abundantly in the sublittoral Mytilus edulis had several strong settling periods with dense down to a depth of2 m, but the following year were replaced and thick beds as a result, and many algae were completely by species normally occupying this zone. covered with small mussels. This has certainly contributed In the upralittoral a vegetation completely comparable to to the impoverishment of the vegetation which has taken that on the old breakwater, was reached on the N side place in Laholm Bay (Wennberg 1987). already in February and March 1975 (after two years). Also in the eulittoral the specie composition and distribution of the algal vegetation wa similar to that on the old breakwater Acknowledgements. I thank Professor Inger Wallentinu for during pring and summer 1975, apart from Cladophora con tructive criticism of the manu cript and Mrs. Ingrid hamosa (= Cl. albida var. biflagellata in van den Hoek Winterlind for reproducing the photos. I am also indebted to 1963). This species has not been observed on the new the Department of Marine Botany, University of Goteborg breakwater so far (summer 1991), but it ha been growing for the u e of everal facilitie . Financial upport for the continuou ly on the outer part of the old one (Wennberg colour pictures was provided by 'kapten Carl Stenholms pers. obs.). fond'. In the subli ttoral a well-developed belt of F. serratus was never establi hed on the new breakwater before the eutrophication led to impoverishment of the flora on both breakwaters and along the whole coast of the Bjare penin­ References sula. A belt of F. serratus became established on the new breakwater already in the summer of 1973, but after three Baden, S. P., Loo, L.-0., Pihl, L. & Rosenberg, R. 1990. Effects of years it was still only about 0.5 m broad, and never got wider eutrophication on benthic communities including fish: Swe­ before the depopulation started. F. serratus did not grow on dish we t coast. - Ambio 19: 113- 122. Eliding, C. 1963. A critical survey of European taxa in Ulvales. the S side. Since 1984 serratus has never been growing F. Part 1. Capsosiphon, Percursaria, Blidingia, Enteromorpha. on any ofthe breakwaters. Already in 1 980, Fucus evanescens -Opera Bot. 8(3): 1-160. and F. vesiculosus disappeared (Wennberg 1987), but in Bokenham, N. A. H. 1938. The colonization of denuded rock 1988 F. evanescens colonized again on the S side, where it surface in the intertidal region of the Cape Peninsula. - Ann. is still growing (Wennberg pers. obs.). Natal Mus. 9: 47-8 1. The growth rate ofthe Fucus species on the new breakwa­ Dayton, P. K. 1975. Experimental evaluation of ecological ter during the first six months (4-5 mm per week) was in dominance in a rocky intertidal algal community. - Ecol. fairly good agreement with corresponding measurements Monogr. 45 : 137- 159. for Great Britain (Knight & Parke 1950). It was higher than Edler, L. 1986. Produktion och naringsupptag av alger. Vaxt­ planktonproduktionen i Laholmsbukten. - In: Ro enberg, R. those for the Danish coast (ea. 5 mm per month, Lund 1936) (ed.) Eutrofieringslaget i Kattegat. Swedish Environmental and records from the Norwegian west coast at Trondelagen Protection Agency Report 3272: 66-7 1. (9- 12 cm per year, Printz 1926). Fleischer, S., Stibe, L. & von Wachenfeldt, T. 1978. Inledande Several species in the understorey of the F. serratus belt undersokningar 1976-78 av gronalgen Cladophora glomerata on the old breakwater never colonized the new one, al- i Laholmsbukten. - Sammanfattande rapport 1. Lansstyrel-

Acta Phytogeogr. Suec. 78 Colonization and succession of macroalgae 77

en i Halland lan. 33 pp. (Mimeographed.) Penin ula, California. - Am. J. Bot. 35: 396-404. Fleischer, S., Rydberg, L., Stibe, L. & Sundberg, J. 1985. Tempo­ Printz, H. 1926. Die Algenvegetation des Trondhjemsfjordes. - ral variations in nutrient transport to the Laholm Bay. - Skrifter Norske Vidensk.-Akad. Oslo I. Mat.-Naturv. Kl. 5: l- Vatten 41: 29-35. (In Swedi h with Engli h ab tract.) 273, pi. 1-10. Hruby, T. & Norton, T. A. 1979. Algal colonization on rocky Rees, T. K. 1940. Algal colonization at Mumbles Head. - J. Ecol. shores in the Firth of Clyde. -J. Ecol. 67: 65-77. 28: 403-437. Jan son, B.-O., Kautsky, N. & Wallentinu , I. 1985. Succession Rosenberg, G. & Ramus, J. 1982. Ecological growth trategie in developments in rocky benthic communitie in the northern the eaweeds Gracilaria foliieraf (Rhodophyceae) and Ulva Baltic proper. - Abstracts, 9th Symp. Baltic Mar. Bioi., sp. (Chlorophyceae): Soluble nitrogen and re erve carbo­ Turku/Abo - Finland, p. 29. (Abstract.) hydrates. - Mar. Bioi. 66: 25 1 -259. Knight, M. & Parke, M. 1950. A biological study of Fucus Rosenberg, R. & Loo, L.-0. 1988. Marine eutrophication induced vesiculosus L. and F. serratus L. -J. Mar. Bioi. Ass. U.K. 29: oxygen deficiency: effect on soft bottom fauna, we tern 439-5 14. Sweden. - Ophelia 29: 213-225. Kornmann, P. & Sahling, P.-H. 1977. Meeresalgen von Helgoland. Rosenberg, R. Elmgren, R., Flei cher, S., Jonsson, P., Pers on, G. Benthische Griin-, Braun- und Rotalgen. - Helgol. Wiss. & Dahlin, H. 1990. Marine eutrophication case tudies in Meere unter . 29: 1-289. Sweden. - Ambio 19: 102-110. Kylin, H. 1944. Die Rhodophyceen der schwedi chen Westkiiste. Rydberg, L., Edler, L., Floderus, S. & Graneli, W. 1990. Interaction - Lunds Univ. Ar kr. N.F. Avd. 2. 40: 1-104. between upply of nutrient , primary production, sedimenta­ Kylin, H. 1947. Die Phaeophyceen der schwedi chen We tkiiste. tion and oxygen consumption in SE Kattegat. - Ambio 19: - Lunds Univ. Ar skr. N.F. Avd. 2. 43: 1-99. 134-141. Lee, R.K.S. 1966. Development of marine benthic algal Stibe, L. & Fleischer, S. 1986. Narsalter - tillforsel och utbyte. communities on Vancouver Island, British Columbia. - In: Till kott fran land. - In: Rosenberg, R. (ed.) Eutrofieringslaget Taylor, R. L. & Ludwig, R. A. (eds.) The evolution of Canada s i Kattegat. Swedish Environmental Protection Agency Report flora. Univer ity Pres , Toronto. pp. 100- 1 20. 3272: 26-32. Lund, S. 1936. Om stofproduktion og vaek t ho nogle Sundberg, J. & Rydberg, L. 1986. Monthly observation of salinity, havbundsplanter. - Beretn. Dan ke Biol. Station 41: 37-50. oxygen and nutrients in a Swedish coastal area during the Luther, G. 1976. Bewuchsuntersuchungen aufNatur teinsub traten years 1982-1 985. - Rep. 47 Dept. Oceanogr., Univ. Gateborg. im Gezeitenbereich des Nordsylter Wattenmeeres: Algen. ­ 30 pp. (Mimeographed.) Helgol. Wiss. Meeresunters. 28: 318-35 1. van den Hoek, C. 1963. Revision of the European species of Markham, J.W. & Munda, I. M. 1980. Algal recolonization in the Cladophora. - Brill, Leiden. 248 pp., 55 plates. rocky eulittoraJ at Helgoland, Germany. - Aquat. Bot. 9: 33- von Wachenfeldt, T. 1975. Marine benthic algae and the environ­ 71. ment in the Ore und. I-III. Di sertation, Univ. Lund. 328 pp. Moore, H. B. 1939. The colonization of a new rocky shore at Wrern,M. 1952. Rocky-shore algae in the bregrund Archipelago. Plymouth. - J. Anim. Ecol. 8: 29-38. -Acta Phytogeogr. Suec. 30: 1-298. Moore, H. B. & Sproston, N. G. 1940. Further ob ervations on the Wallentinus, I. 1984. Compari on of nutrient uptake rate for colonization of a new rocky shore at Plymouth. - J. Anim. Baltic macroalgae with different thallus morphologies. - Ecol. 9: 319-327. Mar. Bioi. 80: 215-225. Murray, S. N. & Littler, M. M. 1978. Patterns of algal succession Wennberg, T. 1987. Long-term changes in the composition and in a perturbated marine intertidal community. -J. Phycol. 14: distribution of the macroalgal vegetation in the southern part 506-5 12. of Laholm Bay, south-we t Sweden, during the la t thirty Niell, F. X. 1979. Structure and succession in rocky algal com­ years. - Swedish Environmental Protection Agency. Rep. munities of a temperate intertidal system. -J. Exp. Mar. Biol. 3290: 1-47. (In Swedish with English summary.) Ecol. 36: 185-200. Wilson, 0. T. 1925. Some experimental observation of marine Northcraft, R. D. 1948. Marine algal colonization on the Monterey algal successions. - Ecology 6: 303-3 1 1.

Acta Phytogeogr. Suec. 78

Chorda tomentosa Ly ngbye in Finnish coastal waters

Guy Hiillfors1and Kaarina Heikkonen2

Abstract Hallfors, G. & Heikkonen, K. 1992. Chorda tomentosa Lyngbye in Finni h coastal waters. -Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-72 1 0-078-8.

Chorda tomentosa is a rare pecies in the northern Baltic Sea. It was observed only twice before, in very mall amount in Finnish coastal waters. Its occutTence in the Baltic Sea proper is reviewed. The occurrence of the specie in the Tvarminne archipelago, at the entrance to the Gulf of Finland, during a period of expansion eau ed by increased salinity in the early 1980s is described. At maximum development in late June 1982 C. tomentosa was observed in unprecedented abundance (up to 50% cover over hundred ofsqu are metres) and size (to more than 60 cm long). The seasonal development of C. tomentosa and the general algal zonation are described for the best investigated locality (SpikarnaSW).

Keywords: Algal zonation; Gulf of Finland; Macroalgae; Nutrients; Rocky shore; Salinity; Tvarrninne archipelago.

' Department of Botany, Hydrobiological Laboratory, University of Helsinki, Fa bianinkatu 24 A, SF-00100 Helsinki, Finland; and Tviimzinne Zoological Station, SF- 10900 Hanko, Finland; 2 City of Helsinki, Centre of the Environment, Department of Environmental Protection, Helsinginkatu 24, SF-00530 Helsinki, Finland.

Introduction

Considerable changes occurred in the hydrography of the (Haahtela & Lehto 1982, Kangas et al. 1982, Kangas 1983, Baltic Sea during the 1970s, which were caused by the Haahtela 1984, Ronnberg 1984, Kangas & Hallfors 1985, influx of saline Atlantic water into the deep basins, followed Ronnberg et al. 1985). by the exchange of water in the deep layers, and upwelling Fluctuations in smaller (filamentous) algal species have in coastal areas. As a result of these proce ses, salinity and been reported by Wallentinus (1974) and Hallfors et al. nutrient concentrations increased in the Baltic Sea proper ( 1984). The basic factors affecting such fl uctuations are still and the western Gulf of Finland (e.g. Brtigmann et al. 1980, poorly understood. Changes in the occurrence of a number Nehring 1981, Nehring & Francke 1981, Hall fors et al. of algae, e.g. Ceramium rub rum (Huds.) C. Ag., Rhodomela 1983, Gronlund & Leppanen 1990). This led to a disturb­ confervoides (Huds.) Silva, Phyllophora spp., Scytosiphon ance in the balance of the littoral communities in the archi­ lomentaria (Lyngb.) Link, Monostroma grevillei (Thur.) pelagos at the southern and southwestern coast of Finland Wittr. , Pilayella littoralis (L.) Kjellm., En teromorpha (e.g. Kangas et al. 1982), including an increased abundance ahlneriana Blid. and Cladophora glomerata (L.) Ktitz., of filamentous green and brown algae, and filtering and were attributed to either increased salinity or eutrophication grazing animals in the hydrolittoral and upper sublittoral by Hallfor et al. (l984). zones. When Fucus vesiculasus was declining, Chorda tomentosa The Fucus community was worst affected in the south­ appeared abundantly in at least one exposed locality in the we tern part of the Finnish archipelago, where Fucus Tvarminne archipelago. The documentation of this unusual vesiculosus L. declined over vast areas and locally even occurrence is the main object of the present study. disappeared completely in the late 1970s and early 1980s

Acta Phytogeogr. Suec. 78 80 G. Hiillorsf & K. Heikkonen

Each time a transect wa investigated, a rope marked at 1-m intervals was laid out along the the transect from the hole to the anchor. The algal zonation and the macroalgal communities were recorded by estimating the cover of each species visible to the naked eye in the field by SCUBA

diving, using a 1 m x 1 m frame at each metre mark along the rope. Becau e the algal communities are layered, the sum of the cover percentages may exceed 100. Critical species were sampled and deterrruned in the laboratory with a Wild M 20 microscope. The investigation period lasted from May to October in 1982. Special attention was given to the occurrence of Chorda tomentosa. Towards the end of the period the easternmost and the most sheltered localities received little attention. Additional ob ervations were made in various part of the Tvarmjnne archipelago during a diving course, and in connection with various other investigations. The terminology relating to the algal zonation fo llows Waern (1952, p. 10), distinguishing a hydrolittoral belt and a sublittoral belt. In the Tvarminne area the hydrolittoral extends from the ummer mean sea level to about 0.7 m depth; the sublittoral is divided into an upper part with

Spikarna Fucus vesiculosus and a lower part without Fucus.

"

5 km Results it SegelskAr During the investigation in 1982 C. tomentosa was found Fig. 1. Map of the Baltic Sea and the Tvarminne area. *=pr evious only at two of the outermost exposed localities, viz. Spikarna published records from the Baltic Sea proper. In the Tvarminne SW and Spikarna N. As C. tomentosa was much more area: fi lled circles = records of C. tomentosa, open circles = abundant in the more expo ed transect, Spikarna SW, this localitie where C. tomentosa was not observed. transect wa chosen for a thorough study. Additional ob er­ vations were obtained from Spikarna N.

Sp ikarna SW, May 23, 1982 Material and Methods The first small plants of C. tomentosa were observed at about 7.5 m depth. Three plants, 1.9-2.5 cm long, were pressed. Thirteen permanent transects were laid out in the archi­ The upper hydrolittoral was dominated by Ulothrix pelago near Tvarminne Zoological Station (Fig. 1 ). The subflaccida Wille and Urospora penicilliformis (Roth) location of each transect was fixed by a hole drilled into the Aresch. The lower hydrolittoral was covered by Pilayella rock close to the shore-line, and a red four-litre pla tic can littoralis with a few interspersed plants of Eudesme virescens filled with concrete serving as an anchor in the deep end (Carm.) J. Ag. and Scytosiphon lomentaria. which usually was level bottom. The upper sublittoral down to a depth of 4.5 m was Six transects were located among the Spikarna, a group of dominated by Fucus vesiculosus, with Elachista fu cicola small skerries in the sea zone. One transect i very exposed, (Yell.) Aresch., Ectocarpus siliculosus (Dillw.) Lyngb. and facing the open sea towards the southwest, one somewhat Pilayella littoralis a the main epiphytes. The undergrowth less exposed on a shore fac ing north. The remaining fo ur consisted mainly of Pilayella littoralis, and scattered plants transects are quite sheltered, being situated in the 'lagoon' of Cladophora rupestris (L.) Kiitz. and Ceramium tenuicorne between the skeJTies. The other tran ects are Langskar and (Ki.itz.) Wrern. Down to about 10 m depth fi lamentous Maskskar on the border between the sea zone and the outer brown algae (especially Pilayella littoralis and Ectocarpus archipelago zone, Allgrundet, Brannskar and Langholmen siliculosus) dominated the algal vegetation. The red algae in the outer archipelago zone, Skabban on the border be­ Furcel/aria lumbricalis (Hud .) Lamour., Phyllophora spp. tween the outer and inner archipelago zones, and Bjomholm and Ceramium tenuicorne were somewhat less abundant. in the inner archipelago zone. For an account of the archi­ Below 10 m Hildenbrandia rubra (Sommerf.) Menegh. had

pelago zonation in the Tvarminne area, see Hayren ( 1931) the greatest cover, up to 50 o/£, while Phyllophora truncata and Luther ( 1951 ). (Pall a ) Zinova reached only 10 %.

Acta Phy1ogeogr. Suec. 78 Chorda tomentosa in Finnish coastal waters 81

Spikarna, SW profile

10

Chorda tomentosa I Fucus vesiculosus � Pilayella littoralis � Ectocarpus siliculosus IJ other species IJ

+

Square 10 20 30 40 50 60

Fig. 2. Spikarna, graphical presentation of the algal community in the SW transect, the site of the main occurrence of C. tomentosa in the Tvarminne area, on June 21, 1982. +=C. tomentosa with < 1 % cover.

Spikarna SW, June 4, 1982 4-4.5 m depth. Audouinella purpurea (Lightf.) Woelk. Scattered small plants of C. tomentosa were found at depths showed a maximum occurrence between 3.2 and 4.4 m between about 6.8 and 7.8 m. depth with up to 20 % cover. Ceramium tenuicorne was still Otherwi e the algal zonation wa very imilar to that very par e in the whole tran ect. C. rubrum wa rare with observed during the previous dive on May 23. Scytosiphon 2 % cover at 4 m depth. Single plants of Rhodomela lomentaria was still present in the hydrolittoral. confervoides were seen at ea. 5 and 14 m depth. In the sublittoral, Cladophora rupestris had considerably increased it cover between 3.0 and 4.5 m, with a maximum Spikarna SW, July 7, 1982 cover of 5 % at ea. 4 m depth. Ceramium tenuicorne was Chorda tomentosa had passed its peak occurrence. Between con picuously sparse; only a few plants were seen down to 5.5 and 9 m it had declined to a cover of2%or less, leaving ea. 8 m, while one ingle plant of Rhodomela confervoides wide light-brown open spaces thinly populated by the was fo und at a depth of 6.8 m. former understorey plant E. siliculosus. Below 9 m C. tomentosa had slightly increased in only three squares, Spikarna SW, June 21, 1982 while in the rest of the transect it had decreased beyond Chorda tomentosa had increased enormously. It was domi­ detection. nant to subdominant between 5.5 and 9.0 m (Fig. 2), and In the hydrolittoral, Urospora penicillifo rmis was still occurred sparsely down to ea. 14.5 m. At maximum occur­ forming a belt with 60 % cover near the mean sea level. rence in the tran ect, between about 6 and 9 m depth, it had Below the Urospora belt, Pilayella littoralis dominated the about 50 % cover, the largest plants measuring between 30 hydrolittoral algal zonation with 50 % cover. Scytosiphon and 60 cm (Fig. 3). Close to the tran ect the abundance of lomentaria reached its seasonal maximum with 20 % cover, C. tomentosa was apparently even higher (Fig. 4). while Eudesme was declining (3%) and Cladophora Otherwise, there were only small changes in the algal glomerata (7 %) still was represented by young plants only. zonation. In the hydrolittoral S. lomentaria and E. virescens In the sublittoral zone changes were insignificant, except had increased to a maximum cover of 5 %. Cladophora for the strong decline of C. tomentosa. During the next dives glomerata had started to grow, while Ulothrix subflaccida on August 14, September 10 and October 16, C. tomentosa had practically disappeared. was not detected any more. In the upper sublittoral, Cladophora rupestris had in­ creased slightly more, with a maximum cover of 10 % at

Acta Phytogeogr. Suec. 78 82 G. Hdllfors & K. Heikkonen

Fig. 3. Average specimens of C. tomentosa collected on June 21, 1982 from the transect Spikarna SW, close to the site where the photograph (Fig. 4) was taken. The fi nely divided fi lamentous species at the bases of the plants is Ectocarpus siliculosus. Pressed material.

SpikarnaN Subsequent observations are scarce. Wrern ( 1950) re­ Detai led observations of the algal zonation are not avail­ ported that dredging below a depth of about I 0 m at able. Judging from the preserved herbarium specimens, C. Huvudsbir, just south of the Stockholm archipelago, might tomentosa occurred mainly at a depth of about 4 m. On May bring up C. tomentosa. Apparently he had found the species 27, 1982 the longest pressed plant measured 29 cm (al­ there, but never published the record. Later (Wrern 1952), though its tip was broken). On June 18 up to 67 cm long he just referred to his previous article. Wrern(1 952), how­ plants were measured. ever, mentioned a new fi nd from Finland, having himself collected the species from Kobbaklintar, in the Aland is­ lands, located in the southwesternmost cornerof the Finnish territory. No details of the find were given. Discussion Wallentinus (1979) reported the species [as Halosiphon tomentosus (Lyngb.) Jaasund] from the Trosa archipelago, Chorda tomentosa was first recorded from the Baltic Sea ea. 55 km WSW of Huvudskar, remarking that it grew on proper from Gotland in the early 1930s (Ridelius J 933; up to hard bottoms or on Mytilus shells between 0.5 and 12 m 30 cm long plants), although the author showed that earlier depth in the outer archipelago, reaching a height up to 45 herbarium specimens from Dalaro (near Stockholm) col­ cm, although normally being only about half that size. She lected in 1886 and 1887-88 also belonged to this species. considered C. tomentosa to be sparse, and to have little Levring ( 1940) still considered the species to be very rare in overall importance for the total plant biomass or the produc­ the Baltic Sea. He observed it only in small stands (plants ea. tivity in the Trosa-Asko area. Quantitative sampling in the 10-25 cm long) at one exposed locality at the end of June, outer archipelago in the Asko area during the 1970s yielded and regarded it to be a spring species. The main occurrence biomasses of C. tomentosa up to around 25 g dry w m-2 of C. tomentosa early in the year is probably the reason why between 3 and 12 m depth in May-June, and even denser there are so few published records of the species in the populations were occasionally seen by divers (I. Wallentinus Baltic Sea (see further below). pers. comm.).

Acta Phytogeogr. Suec. 78 Chorda tomentosa in Finnish coastal waters 83

Fig. 4. Underwater photograph of massive growth of C. tomentosa at ea. 8 m depth near the transect SpikarnaSW on June 21, 1982.

In the offshore areas of Salvorev, Sando bank and least several hundreds of square metres of rocky bottom Kopparstenarna, north of Gotland, Kautsky (1984, 1989) between about 4 and 9 m depth. At least on a local level this observed the species in apparently fairly large amounts (up is contradictory to the statement ofWallentinus ( 1979), that to ea. 30 g dry w m-2) in May-June 1983. "the species has little importance for the plant biomass or In the southern and western Baltic Sea, C. tomentosa productivity of the [Asko] area as it is so sparse ...". The seems to have received little attention, although it appears to development of the species at Spikarna was very rapid in the have been fo und at several localities. There are published beginning of June. This agrees with the observation by records of the species from Hidden see (Kiinzenbach 1955/ Kristiansen (1972) who observed a rapid development in 56), Bornholm (Rosenvinge & Lund 1947) and the Kiel spring of this annual alga in the bresund. Because of the Bight (Hoffman 1953, Schwenke 1964). It is abundant in more northernlo cation of the Tvarminne area compared to the bresund area (e.g. Kristiansen 1972, von Wachenfeld the bresund, the time of the fastest development is delayed 1975). These geographical areas are, however, outside the here until early summer. scope of the present article. The year of 1982 was clearly a 'brown algal year' in the After Chorda tomentosa was first recorded from the sense of W::ern (Wallentinus 1974). Green and red algae, Tvarminne area by South (1965), the species was only seen particularly Cladophora glomerata and Ceramium tenui­ occasionally by T. Strandstrom (pers. comm.), when diving corne were strikingly sparse in the investigated transects, in the same locality in the late 1960s. All these early especially in the hydrolittoral. specimens appear to have been very small, hardly exceeding Chorda tomentosa is a marine species reaching its lower 10 cm in length. When the junior author (K.H.) made a limit of salinity tolerance in the northern Baltic Sea. In the training dive at Segelskar on July 4, 1981, specimens meas­ Tvarminne area, the salinity of the Baltic surface water was uring about 25 cm were found at ea. 8 m depth, but only ea. 0.5- 1 .0 %o higher than normal in the late 1970s and early fragments were recovered for documentation. 1980s, frequently exceeding 6.5 %o and occasionally reach­ In 1 982, C. tomentosa was dominant or subdominant on at ing even 7 %a (Hallfors et al. 1983). Still, in the spring of

Acta Phytogeogr. Suec. 78 84 G. Hiillfors & K. Heikkonen

1982, salinity remained between 6 and 7 %o in the northern Asko Lab. Univ. Stockholm. 65 pp. (Mimeographed.) Baltic proper for more than a month (Leppanen & Alenius Kaut ky, H. 1989. Quantitative distribution of plant and animal 1988, Fig. 7). Thus the increased salinity seems to have communities of the phytobenthic zone in the Baltic Sea. - promoted the increased frequency of C. tomentosa in the Contr. A ko Lab. Univ. Stockholm 35: 1-80. Kristiansen, Aa. 1972. A seasonal study of the marine algal Tvarminne area, while raised nutrient concentrations appar­ vegetation in Tuborg harbour, the Sound, Denmark.- Bot. ently contributed to the large size and large cover of the Tidsskr. 67: 20 1 -244. species. During the late 1980s and early 1990s C. tomentosa Kunzenbach, R. 1 955/56. Dber die A1genvegetation der Ostsee und decreased considerably in abundance. der Boddengewas er urn Hiddensee. - Wiss. Zeitschr. Ernst­ Moritz-Arndt-Univ. Greifswald, Math.-Nat. Reihe 5: 373-388. Leppanen, J.-M. & Alenius, P. 1988. Cycling of organic matter Acknowledgements. We thank Inger Wallentinus for valu­ during the vernal growth period in the open northern Baltic able comments on the manuscript and Ingrid Winterlind for proper. I. Hydrography, currents and related factors. - Finn. making the photograph of the pressed material. The study Mar. Res. 255: 3-18. Levring. T. 1940. Studien uber die A1genvegetation von Blekinge, was financed by the Walter and Andree de Nottbeck Foun­ Sudschweden.-Dis ertation, Univ. Lund. 178 pp. dation. Luther, H. 1951. Verbreitung und Okologie der hoheren Wasser­ pflanzen im Brackwa ser der Ekenas-Gegend in Sudfinnland. I. Allgemeiner Teil. -Acta Bot. Fenn. 49: 1-23 1. Nehring, D. 1981. Hydrographi ch-chemische Untersuchungen in References der Ostsee von 1969- 1978. II. Die chemischen Bedingungen und ihre Veranderungen unter besonderer Berucksichtigung Brtigmann,L., Nehring, D. & Rohde, K.-H. 1980. Zur Verteilung des Nahrstoffregimes. -Geodat. Geophysikal. VerOff. (Rei he einiger Schadstoffe in der Ostsee. - Geodat. Geophysikal. IV) 35: 39-112. VerOff. (Reihe IV) 31: 1-39. Nehring, D. & Francke, E. 1981. Hydrographisch-chemische Gronlund, L. & Leppanen, J.-M. 1990. Long-term changes in the Untersuchungen in der Ostsee von 1969- 1978. I. Die nutrient re erves and pe1agic production in the western Gulf of hydrographischen Bedingungen und ihre Veranderungen. ­ Finland. - Finn. Mar. Res. 257: 15-27. Geodat. Geophysikal. VerOff. (Reihe IV) 35: 5-38. Haahte1a, I. 1984. A hypothe is of the decline of the bladder wrack Ridelius, K.G. 1933. Nagra markligare havsalgfynd fran Got1and. (Fucus vesiculosus L.) in SW Finland in 1975-1981. - - Sven. Bot. Tidskr. 27: 77-96. (In Swedish with German Limnologica (Berlin) 15: 345-350. summary.) Haahtela, I. & Lehto, J. 1982. Rakkolevan (Fucus vesiculosus) Ronnberg, 0. 1984. Recent changes in the distribution of Fucus esiintyrninenvuosin a 1975-1 980SeilinalueellaSaaristomerella. vesiculosus L. around the Aland islands (N. Baltic). -Ophelia, [The occurrence of bladder wrack (Fucus vesiculosus L.) in Suppl. 3: 189- 193. 1975- 1 980 in the Seili area, Archipelago Sea.] - Mem. Soc. Ronnberg, 0., Lehto, J. & Haahtela, I. 1985. Recent changes in the Fauna Flora Fenn. 58: 1-5. (In Finnish with Engli h ab tract occurrence of Fucus vesicula u in the Archipelago Sea, SW and legend , and Swedish summary.) Finland. - Ann. Bot. Fenn. 22: 23 1-244. Hallfors, G., Leskinen, E. & Niemi, A. 1983. Hydrography, chlo­ Rosenvinge, L.K. & Lund, S. 1947. The marine algae of Denmark. rophyll a and nutrients at Tvarminne Storfj ard, Gulf of Finland, Contributions to their natural history. Vol. II. Phaeophyceae. in 1979/80. - Sci. Rep. W. & A. Nottbeck Found. 4: 1-19. Ill. Encoeliaceae, Myriotrichiaceae, Giraudiaceae, Striariaceae, Hallfors, G., Kanga , P. & Niemi, A. 1984. Recent change in the Dictyo iphonaceae, Chordaceae, and Laminariaceae. - K. phytal at the south coast of Finland. - Ophelia, Suppl. 3: 51- Danske Vidensk. Selsk. Biol. Skr. 4 (5): 1-99. 59. Schwenke, H. 1964. Vegetation und Vegetation bedingungen in Hayren, E. 1931. Aus den Scharen Sudfinnlands. - Verh. Int. der westlichen Ostsee (Kieler Bucht). - Kieler Meeresforsch. Verein. Limnol. 5: 488-507. 20: 157-168. Hoffman, C. 1953. Neufunde von Benthosalgen in der Kieler South, G.R. 1965. A record of Chorda tomentosa Lyngb. in the Bucht. - Kieler Meeresfor eh. 9: 228-230. Gulf of Finland. - Mem. Soc. Fauna Flora Fenn. 41: 5-6. Kangas, P. 1983. Forandringar i bHist

Acta Phytogeogr. Suec. 78 Primary production of macroalgae in relation to the spectral range and sublittoral light conditions in the Tvarminne archipelago, northern Baltic Sea

Elina Leskinen1, Anita Miikinen2, Wilhelm Fortelius3, Magnus Lindstrom3 & Heikki Salemaa4

Abstract Le kinen, E. et al. 1992. Primary production of macroalgae in relation to the spectral range and sublittoral light conditions in the Tvlirminne archipelago, northern Baltic Sea - Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-72 1 0-078-8.

The effects of photon fluence rate and light quality on the primary production of dominant Baltic rnacroalgae with diffe rent functional morphology were studied. The experiments were carried out in the laboratory, both in summer and in winter, by measuring the carbon fi xation. We also measured the diurnal changes in the primary production rates of rnacroalgae in situ in July, when the biomass and diversity of macroalgae are highe t. In all experiments the production was highly affected by the thallus morphology. The highest specific rates were measured for fi lamentous algae. The long lived corticated and leathery species had value about 10-15 % of those of the filamentous algae. The production rate of Fucus vesiculosus was usually highest in the apical parts of the thallus, and lowest in the basal parts. The basal cortex wa , however, highly productive, occasionally exceeding the photosynthetic rates of the apical thalli. In the laboratory experiment, the difference between production rates in summer and winter was small, partly due to higher chlorophyll contents in winter, which improves the potential production capacity. Increased photon fluence rate from 10 to 18jlmol photons rn-2s-1 resulted in an increase in photosynthetic activities for all algae. Production rates under different spectral ranges correlated with the action spectra of the green, brown and red algae. In itu, the average production rate was 2-6 jlg C (mg total C)-1 h-1 for the fi lamentous algae, and about 10% of that for Fucus vesiculosus and the coarse structured red algae. Mo t species showed bimodality in their photosynthetic activity during the day. The phenomenon was mo t distinct in algae with higher light- aturation level living close to the surface, such as the light adapted Cladophora glomerata and Pilayella littoralis. The highest photon fluence rates appeared to have an inhibitory effect on the production of Phyllophora truncata.

Keywords: Carbon fi xation; Laboratory experiment; Photo fluence rate; Photosynthesis.

1 Departntent of Ecological Botany, University of Uppsala, P. O.Box 559, S-751 22 Uppsala, Sweden; 2Department of Biology, University of Turku, SF-20500 Turku, Finland; 3Tviirminne Zoological Station, SF- 10900 Hanko, Finland; 4/nstitute of Zoology, Department of Ecology, University of Helsinki, Pohjoinen Rautatiekatu 13, SF-00100 Helsinki, Finland.

Introduction species displays a distinct patternof seasonal succession, and the zonation of the algae according to their depth is also The macroalgal diversity in the Baltic Sea is low, due to the fairly distinct (e.g. Du Rietz 1932, Wrern 1952, Hallfors et low salinity. The number of conspicuous species observed al. 1981). in the phytal belt is reduced from 154 at the western coast of The northern Baltic Sea environment is very extreme. In Sweden to 31 at the southwestern coast of Finland, with a winter, the sea is covered by ice, the water temperature is salinity of ea. 5-6 %o (Hallfors et al. 1981). The number of close to freezing point, and even during daytime, insolation macroalgae, which constitute the highest biomass and cover, is negligible. In summer, the water temperature may exceed is only about 15 species. The abundance of these dominant 20 °C, and the daily period with light sufficient for photo-

Acta Phytogeogr. Suec. 78 86 E. Leskinen et al.

Table l. Macroalgae used in the experiment , their morphology and habitat. Date for the experiment : I =July 7, 1988; 2 = March I, 1989, laboratory experiments, and 3 =June 28-29, 1989, in situ experiment.

Species Thallus Habitat Experiment

CHLOROPHYTA Urospora penicil/iformis (Roth) Aresch. fi lamentous, not branched geolittoral-hydrolittoral 2

Cladophora glomerata (L.) KUtz. filamentou , branched geolittoral rockpool I hydro I i ttoral I, 3 C/adophora rupestris (L.) KUtz. filamentou , branched sublittoral 3

PHAEOPHYTA Pilayella littoralis (L.) Kj ellm. fi lamentous, branched hydrolittoral-subl i ttoral 2, 3

Dictyosiphon fo eniculaceus (Huds.) Grev. filamentou , corticated hydrolittoral- ublittoral

Fucus vesiculosus L. parenchymatic, leathery ublittoral 1, 2, 3

RHODOPHYTA Ceramium tenuicorne (KUtz.) Waern fi lamentou , corticated hydrolittoral- ublittoral I, 2, 3

Furcellaria lumbricalis (Huds.) Lamour. p eudoparenchymatic, cortjcated sublittoral l, 2, 3

Phyl/ophora truncata (Pall.) Zinova p eudoparenchymatic, leathery subljttoral 2, 3

synthesis, can be up to 18 hours (Jansson & Wulff 1977). Bothnian Sea. His records of the vertical distribution of the The periodicity of light has been shown to regulate the algal belts made by diving in the 1940s are significant reproduction of perennial species, such as Fucus vesiculosus references today, because of the recent decline of the fucoid (Back et al. 1991). The significance of light conditions vegetation in the northern Baltic area. The e ecological should also be emphasized because of an inflow of humic changes eem to be caused by eutrophication of the coastal fresh water which decrea es light penetration, making the water in the Baltic Sea (e.g. Kanga et al. 1982, Kautsky et Baltic Sea water look greeni h; even more o during plank­ al. 1986, 1992). ton blooms. Since the 1970s, several tudies have been made on the The theory of complementary vertical adaptation of ma­ primary production of macroalgae in the Baltic Sea. Most rine algae dates back to the last century. Engelmann (1893) extensive investigation were performed in project con­ ugge ted that the pigmentation of the main taxonomic algal centrating on the energy flow analysis and ecosystem mod­ groups was an adaptation to the light conditions prevailing elling oflittoral communitie (Jans on & Wulff 1 977, Jan on at different depths in the sea. For further di cus ion, see et al. 1982). Wallentinus (1976, 1978, 1979) elucidated the Ramus (1983) and the review by Kirk (1983). Early papers production of morphologically different taxa in the different on algal zonation are also found in the Nordic countries. As seasons. Guter tarn et al. (1978) carried out diurnal mea - early as 1844, Orsted pointed to the connection between urements on the photosynthetic activity of Fucus vesiculosus light and the zonation of algae, and named three algal zones and Cladophora glomerata. Kairesalo & Leskinen (1986) in the littoral of the Oresund: 1. Regio algarum viridium, the published results of fucoid primary production rates mea - green algal zone from the surface down to two or three ured in situ in the Tvarminne archipelago, the site of the fathoms (3.5-5.5 m), 2. Regio algarum olivacearum, the present study. brown algal zone from three to seven fathoms (5.5-12.5 m), Information on the metabolic activities of diffe rent algal and 3. Regio algarum purpureanum, the red algal zone from species are continuously needed for environmental moni­ seven to twenty fathoms (12.5-35 m). In summer, this toring purposes since even slight coastal eutrophication general zonation pattern with its narrower zone is found in readily affectsthe macroalgal primary production and con­ the Baltic Sea, excluding the Bothnian Bay and the eastern­ sequently may change the dominance relationships of the most part of the Gulf of Finland. species in the northern Baltic rocky-shore communities Detailed documentations of the vertical distribution of (Kangas et al. 1982). On the other hand, mechanisms of algae, also providing historical reference material for envi­ biotic disturbances caused by selective herbivory (Salemaa ronmental monitoring, are unfortunately few. One excep­ 1987, Tuomi et al. 1989) make it necessary to examine tion is Mats Wrern's (1952) investigation in the Oregrund primary production rates on the microscale even in the archipelago at the border between the Aland Sea and the morphologically differentiated parts of individual thalli

Acta Phytogeogr. Suec. 78 Primaryproduction of macroalgae 87

(Guterstam et al. 1978, Kairesalo & Leskinen 1986). Photon fluence rate To be able to understand the complicated causal relations �J.mol photons m-2 s-1 of the changing ecosystem, knowledge of the basic proc­ 0.3 es es is necessary at the species level. The aim of our study was to investigate the relationship of light conditions and macroalgal primary production in the SW archipelago of Finland. We have focused our activities on: 1. Experimental 0.2 studying of the effects of photon fluence rate and light Tmax quality on the production rates of macroalgae with different functional morphology, both in summer and in winter. 2. Measuring the diurnal changes in the production rates of 0.1 macroalgae. 3. Comparing whether the species specific differences in production rates measured in the laboratory are consistent with those observed in nature. 0 400 500 600 700

Wavelength, nm Material and Methods

This study was carried out in the Tvarminne archipelago, Fig. 1. Spectra of light used in the laboratory experiments. The SW coast of Finland. The hydrography of the area is de­ curve represent the higher light intensities in Table 2. FWHM = full width of spectrum at half maximum intensity. Red light could scribed in greater detail by Nierni (1975) and the ecology of not be filtered out completely from the blue and green light, which the algal belts by Hallfors et al. (1975). The classification of thus al o emitted some red light, starting at 640 and 720 nm, littoral zones follows that adopted by Wrern (1952). The respectively. algae, typical of the rocky shores in the outer archipelago zone, were collected for experiments from the upper littoral by hand and from deeper water by diving. The species, their functional morphology and habitat are summarized in Table 1.The seasonality of the algae caused some variation in the species used in the experiments. Effects of light quality on primary production Fucus vesiculosus is morphologically the most special­ ized of the algae studied, and thus production was mea ured Six pecie of green, brown and red algae were used in the in three different parts of its thallus: the apices, the wing at experiments both on July 13, 1988 (Tables 1 and 3) and the upper part of the thallus (measured only in the in situ March 1, 1989 (Tables 1 and 4). The algae were incubated in experiment) and the base. The outer cell layer of the base, the laboratory under three different spectral ranges and two the cortex, contains chlorophyll, whereas the inner part is photon fluence rates (Table 2). specialized into a tough tissue without chlorophyll. In the The experimental light environment was constructed by experiments, an effort was also made to measure the pro­ suspending the incubation bottles 9 ern above the bottom of duction rate and chlorophyll a content of detached cortex a constant temperature bath. Copper sulphate (3 g I-1 ) was separately from the rest of the base. added to the bath medium to reduce the strong red and infra­ red part of the light. The light source (Argaphoto- BM, 220 V 500 W) was placed under the incubation basin, allowing the light to reach the algal specimens from below. Addi­ tional fi lters (Rosco Supergel: B1illiant blue, no. 69, Moss green, no. 89, Light red, no. 26) were placed between the light source and the bottom of the incubation basin to obtain the three spectral ranges, here called blue, green and red Table 2. Light characteri tics for the laboratory experiments on (Table 2, Fig. 1). Two photon fluence rates were used, both July 13, 1988 and March 1, 1989. FWHM = the width ofspectrum close to the compensation points of Baltic macroalga (cf. (in nm) at 50 % of the maximum transmi ion. Wallentinus 1978). The photon fluence rates were regulated by the number of light bulbs (1 or 2), and by adjusting the Colour Tran mission FW HM, Photon fluence rate, }lmol m-2 s- 1 maximum, nm nm Lower Higher distance between the light source and the incubation basin. The light intensity and spectrum in the incubation basin was

Blue 485 72 9.8 18.1 measured at the site of the incubated algae with a QSM- Green 529 58 10.3 17.7 2500 quantum spectrometer (Techtum Instruments, Umea, Red 644 78 10. 1 17.8 Sweden).

Acta Phytogeogr. Suec. 78 88 E. Leskinen et al.

1 1 1 1 Table 3. Primary production [J...lg C(mg total q- h- ; x = mean of Table 4. Primary production [ J...lg C(mg total q- h- ; x = mean of three measurements; CV %=coeff icient of variation] on July 13, three mea urements; CV %= coefficient of variation] on March I, 1988, at three spectral ranges and at two light intensities. Water 1989, at three spectral ranges and at two light intensities. Water temperature during the incubation: 15 °C. temperature during the incubation: 5 °C.

Wavelength Blue Green Red Wavelength Blue Green Red 400-500 nm 500-600 nm 600-700 nm 400-500nm 500-600 nm 600-700 nm

Light inten ity (I0 Jlmol m-2 (CV %) (CV %) (CV %) Light intensity ( 10 Jlmol m-2 -1) x (CV %) x (CV %) x (CV %) -1) x x x

Species Species CHLOROPHYTA CHLOROPHYTA Urospora Cladophora (rockpool) 2.91 (42.7) 0.86 (44.9) 2.80 (24.1) 3.54 (20.7) 3.18 (28.6) 3.44 (13.9) Cladophora (hydrolittoral) 1.66 (21 .7) 0.74 (73.4) 1 .80 (44.2) PHAEOPHYTA Pilayella . PHAEOPHYTA 1.57 (67.3) 1 .96 (33.8) 1 20 (41 .7) Fucus (a ex) 0.56 0.9 ( 6.4) 0.54 Dictyosiphon 0.95 (31 .8) 0.73 (13.0) 1 .17 ( 11. 1) p (23.3) 1 1 (29.9) Fucus (base) 0.05 (41 .7) 0.03 (69.1) 0.04 ( 14.2) Fucus (apex) 0.16 (28.6) 0.89 (24.2) 0.49 (58.1) Fucus (cortex) 0. 9 0.30 (8.3) 0. 6 ( 4.0) Fucus (base) 0. 14 (23.5) 0.13 (24.2) 0.22 ( 1 8.7) 1 (23.0) 2 1 Fucus (cortex) 0.41 ( 19.9) 0.51 (31 .3) 0.35 (76.7) RHODOPHYTA Ceramium RHODOPHYTA 0.48 (12.2) 0.75 (10.3) 0.16 (6.3) Phyllophora .56 ( 12.6) 0.47 Ceramium 1 .59 (32.9) 2.48 (37.5) 1 .32 (29.4) 0.67 (74.6) 1 (22.9) Furcellaria 0.39 0.48 (8.8) 0.25 Furce/laria 0. 18 (76.6) 0.80 (76.6) 0.43 (17.5) ( 16.9) (4.9)

- - 2 Light intensity ( 18 Jlmol m- s-1) (CV %) X (CV %) (CV %) -2 - 1 X Light intensity (I8Jlmol m ) X (CV %) x (CV %) X (CV %) CHLOROPHYTA CHLOROPHYTA Urospora 6.26 ( 18.4) 2.14 (-) 5.83 (13.6) Cladophora (rockpool) 7.23 (3.1) 4.80 (2.6) 5.80 (22.3) Cladophora (hydrolittoral) 2.81 ( 19.5) 1 .34 (30.9) 2.37 ( 15.8) PHAEOPHYTA Pi/aye/la 6.79 (51 .9) 5.15 (2.5) 2.46 (51 .2) PHAEOPHYTA Fucus (apex) 1 . 11 (20.2) 0.94 (22.8) 0.67 ( 13.4) Dictyosiphon 2.56 (48.9) 1 .66 (26.6) 1 .85 (15.5) Fucus (base) 0. 10 (41 .0) 0.13 ( 13.1) 0.02 (60.6) Fucus (apex) 0.92 (30.5) 0.93 (39.0) 0.62 ( 13.2) Fu.cus (cortex) 0.71 (32.0) 0.38 (17.4) 0.42 ( 11.2) Fucus (base) 0.06 (69.4) 0.07 ( 13.9) 0. 11 (54.1 ) Fucus (cortex) 0.39 (58.5) 0.72 (35.5) 0.90 (36.3) RHODOPHYTA Ceramiwn 1 .37 ( 1 3. 1 ) 1 . 1 3 (15.8) 0.23 (31 .6) RHODOPHYTA Phyllophora 1 .87 (16.0) 1 .73 (4.2) 0.84 (25.7) Ceramium 4.08 (8.6) 3.43 (14.2) 2.22 (2.9) Furcellaria 0.62 (23.0) 0.51 ( 12.0) 0.34 (15.1) Furcellaria 0.80 (32.1 ) 1.07 (6.1) 0.96 (7.9)

A modification of the methods of Aertebjerg Nielsen & Diurnal fluctuations in primary production Bresta ( 1984) and Wallentinu (1976) wa used for measur­ ing the macroa1gal carbon fi xation. About 5-10 mg (wet Fifteen in situ incubation for mea uring the diurnal fluctua­ weight) pieces of algae were immersed in 70 ml of fi ltered tion in the primary production were carried out during one 14 sea-water. A olution of N� C03 (100 Ill, 20 !lCi) was day and night on June 28-29, 1989 (Fig. 2). Seven specie of added, and the algae were incubated in the different light macroalgae were used in the measurements. About 5-10 mg conditions for 30 min. On July 13, 1988, the sea-water (wet weight) pieces of algae were immersed in 20 ml of 14 temperature was 15 °C, and on March 1, 1989, it was 5 °C. filtered sea-water. A solution of Na2 C03 (100 Ill, 20 !lCi) To avoid a temperature shock to the algae, the temperature was added, and the algae were incubated for 20 min. Before in the incubation basin was kept at 15 oc and 5 °C, respec­ and after the incubation, the algae were protected from tively, during the incubation . direct sunlight. The light at the incubation depth, 3.5 m, was After incubation, the algae were rinsed with 1 N HCl to measured with the QSM-2500 quantum spectrometer liberate inorganic 14C, then dried (24 h, 70 °C) and weighed. during each incubation period (Fig. 3). The sea-water tem­ After that, the algae were immersed in a tissue solubilizer perature was about 15 oc during the measurements. (NCS, 24 h), cintillation liquid (PCS) was added and the Production rates were measured by applying the radio amount of 14C incorporated was measured with a scintilla­ carbon technique used by Kairesalo & Leskinen ( 1986), tion counter ( 1215 RackBeta, LKB-Wallac) u ing an exter­ which allows the calculation of results per unit of total nal standard channel ratio method for standardization. The organic carbon without using a coefficient. After the incu­ result were related to total carbon by using a dry weight/ bation, the algae were rinsed with 1 N HCl, and then about total carbon coefficient later determined for the diffe rent 0.5 mg (dry weight) subsamples were combusted in an algal species. Each of the re ults is a mean of three replicate infrared gas analyzer for analysis of total carbon. The 14 samples from separate algal individuals. The values were radioactive carbon was trapped as C02 from the outflow corrected for the dark uptake of 14C. gas in a gas-liquid exchange column, and the absorbent

Acta Phytogeogr. Suec. 78 Primaryproduction of macroalgae 89

(6 mJ Lumasor, II, Lumac) was run directly into a scintilla­ Table 5. Macroalgal chlorophyJI a content [J.!g chl. a (mg total 1 C)- ; = mean of three measurements; CV% = coefficient of tion vial attached to the column. Scintillation liquid (10 rnl X: Carboluma, Lumac) was added and the radioactivity was variation] on March 1, 1989 and June 29, 1989. measured with a scintillation counter ( 1215 RackBeta, LKB­

Wallac ). The results were related to total carbon, and each of Species March 1, 1989 June 29, 1989 the results is a mean of three replicates from separate algal individuals. The values were corrected for the dark uptake x (CV %) x (CV %) of 14C. CHLOROPHYTA Cladophora glomerata 6.75 (5.3) 20.25 (44.6) Chlorophyll a measurements Cladophora rupestris Urospora 57.66 ( 1.1) Chlorophyll a contents of the algae were measured in March PHAEOPHYTA and June 1989 by extracting the pigments in 90 % acetone. Pilayella 28.24 (5.9) 10.50 (44.2) The algae samples were first weighed and then carefully Fucus (apex) 4.07 (L3.6) 6.75 (8.7) crushed in a mortar. After incubation for 24 hours, the Fucus (base) 4.71 (34.7) 4.50 (21 .2) absorbance of the acetone solution was measured with a Fucus (cortex) 17.72 (26.4) 40. 10 (16. 1) spectrophotometer at 665 nm in 1 cm cells (Strickland & RHODOPHYTA Parsons 1972). The chlorophyll concentrations were calcu­ Ceramium 11.28 (6.0) 3.75 (15.9) lated using a specific absorption coefficient of 89 (Marker et Phyllophora 12.65 (14.9) 17.69 (37.2) 9.98 4.50 al. 1 980). The results were calculated per unit of total carbon Furcellaria (30.2) (5.3) by using a wet weightltotal carbon coefficient determined for each algal species.

independent photosynthetic activities were observed earlier by King & Schramm (1976) in the Kiel Bight. In the Results and Discussion Tva.nninne archipelago, some of the filamentous algae con­ tinued their growth during the mild winter 1988-89 with Primary production rates under different temperature exceptionally poor ice cover. In the laboratory, the level of and light conditions production rate of the filamentous, green alga Urospora penicilliformis averaged 2.14-6.26 jlg C (mg total C)-1 h-1 The primary production of the macroalgae was affected and the brown alga Pilayella littoralis 2.46-6.79 jlg C (mg both by the photon fluence rate and the wave lengths of light total C)-1 h-1 under the stronger photon fluence rate (18 (Tables 3 and 4). As predicted (cf. Wallentinus 1978, Littler j..tmol photons m-2s-1 ). These values are well comparable & Littler 1980), the response to light varied between differ­ with the values measured for Cladophora glomerata and ent species, and the production rate did not depend on the Ceramium tenuicorne in summer. Consequently, the suc­ taxonomical affinities, but mostly on the thallus morphol­ cessive seasonal changes in the structure and productivity of ogy. The long-lived corticated and leathery species could be the littoral communities may be significantly influenced by identified as the late successional forms sensu Littler & unpredictable climatic variations regulating the ice cover, Littler (1980). Those species had low production rates also and hence light available for the algae in the northern Baltic in the laboratory summer experiment (Table 3), under the Sea. Wallentinus (1976) suggested that harsh winter condi­ stronger photon fluence rate ( 18j..tmol photons m-2s-1 ). The tions will be compensated by higher chlorophyll contents, production rate was 0.80- 1.07 jlg C (mg total C)-1 h-1 for improving production capacity. This is supported by our Furcellaria lumbricalis and 0.06-0.93 jlgC (mg total C)-1 observations on the high chlorophyll a values in late winter h-1 for Fucus vesiculosus, depending on the light colour compared to those in summer in the filamentous algae during the incubations. Highest summer production rates (Table 5). Extraordinarily high pigment contents were meas­ were measured for the opportunistic filamentous algae, ured in the ephemeral high-littoral V rospo rapenicilli fo rmis, 1 .34-7 .23 j..tg C (mg total C)-1 h-1 for Cladophora glomerata which has its productive peak during the dark winter period and 2.22-4.08 jlg C (mg total C)-1h-1 for Ceramium (Wrern 1965). In Fucus vesiculosus, no striking seasonal tenuicorne,both with the main part of the thalli persisting variation was observed in the chlorophyll a contents, except for one growing season only. for the cortical tissue of the base, which was rich in photo­ It is noteworthy that the Baltic algae are generally well synthetic pigments in the summer. It is interesting to note adapted to low temperatures (Russell 1985). In our winter that also the light compensation level for the Baltic macro­ experiments, the production rates of the coarse species were algae seems to fluctuate seasonally, being lower in winter not much lower than in the summer (Tables 3 and 4). These than in summer (King & Schrarnm 1 976, Wallentinus 1 978). results may be a consequence of the photon fluence rate Increased photon fluence rate from 10 to 18j..tmol photons during the incubations, but the same kind of temperature m-2s-1 enhanced photosynthesis of the macroalgae

Acta Phytogeogr. Suec. 78 90 E. Leskinen et al.

Primary production rate

JlQC (mg total CJ-Ih-l Jl9 c (mg total c)-1h-1 20 20 Cladophora glomerata Pilayella littoralis

15 15

10 10

0 i •• • • • 101112 14151617 19 21 23 3 4 8 11011 12 14151617 19 21 23 3 4

Jl9 c (mg total cr1h-1 Jl9 C (mg total C)-1h-1J .. 20 2.0 Cladophora rupestris Fucus vesiculosus apex 15 1.5

10 1.0

0.5

.L 0 i ••• • • o I • 8 1011 12 14151617 19 21 23 3 4 1011 12 14151617 19 21 23 3 4

Jl9 c (mg total cr1h-t Jl9 c (mg total c)-lh-1 20 2.0 Ceramium tenuicorne Fucus vesiculosus wing 15 1.5

10 1.0 hh 0 • • • • 101112 14151617 19 21 23 3 4 8 1011 12 14151617 19 21 23 3 4 6

JlQ c (mg total cr'h-1 Jlg c (mg total c)-1h-1 2.tJ 2.0 Phyllophora truncata Fucus vesiculosus base 1.5 1.5

1.0 1.0 0.5 0.5 1.1 • • 0 • I 0 • .lli I • 1011 12 14151617 19 21 23 3 4 1011 12 14151617 19 21 23 3 4

JlQ c (mg · total c)-lh-1 Jl9 c (mg total c)-lh-1 2.0 2.0 Furca:lat ia lumbricalis Fucus vesiculosus cortex 1.5 1.5

1.0 1.0

0.5

i 0 1011 12 14151611 19 21 23 3 4 1011 12 14151617 19 21 23 3 4 Time Time

Fig. 2. The specific production rates [llgC (mg total C)-1 h-1 ] of the macroalgae incubated diurnally in June 28-29, 1989. The tandard deviations are expre sed as bars on the top of the columns. The times at the end of the incubations are shown below the x-axis. Note the diffe rent cales on the y-axis.

Acta Phytogeogr. Suec. 78 Primaryproduction of macroalgae 91

Photon fluence rate blue light. This was true for Pilayella littoralis and all 2 1 examined red algae in winter, as well as Ceramium f..Jmol photons m- s- tenuicorne, Cladophora glomerata and Dictyosiphonfoeni­ 300 culaceus in summer. In low-inten ity light, apical parts of Fucus vesiculosus were most productive in green light both in summer and in winter, whereas the activity of the cortical 200 tissue removed from the base changed seasonally. In the higher photon fluence rate, the cortex had the highest rates in the red light in summer, but in the blue light in winter 100 (Tables 3 and 4). These ob ervation may be related to the seasonal changes in the physiological stage of the alga, as also indicated by the increa ed chlorophyll contents of the 0 +----.----,--.----.--,----.------.-.;:oo...... ,...... __,.--==':;_;.....---. 8 12 16 20 24 4 8 fucal cortex in summer (Table 5). Time 2 1 Fig. 3. Photon fluence rate ()...lmol photons m- h- ) at the incubation Diurnal fluctuations in the macroalgal primary depth (3.5 m) during the experiment in June 28-29, 1989. production

The diurnal fluctuation in the primary production wa meas­ ured in July, when the algal biomass and diversity are near imilarly in both winter and umrner, regardless of the their seasonal maximum. The results of the diurnal incuba­ incubation temperature (Tables 3 and 4 ). As a rule, the green tion serie are illustrated in Fig. 2 with the corresponding algae almost doubled their production rates, the increase light curve in Fig. 3. The maximal theoretical photon fluence being highest (over fivefold) in chlorophyll-a-rich rate was at about 1.00 p.m. Cladophora glomerata from a rockpool (Table 5) at the We can roughly generalize that the average production higher photon fluence rate in green light (Table 3). Both rate, mea ured as carbon fixation, was 2-6 �g C (mg total 1 Dictyosiphon fo eniculaceus in summer (Table 3) and C) -I h- for the filamentous algae, and about 10% of that for Pilayella littoralis in late winter (Table 4) more than dou­ Fucus vesiculosus and the coarse-structured red algae. Most bled their production rates. The simi larity in their behaviour species showed bimodality in their photosynthetic activity can be understood on the basis of the close re emblance of during the day. The first maximum was at 10.00 a.m., about their light-saturation curves (Wallentinus 1978) in the re­ seven hours after sunrise. The second maximum wa be­ spective seasons. Fucus vesiculosus benefited mo t from tween 2.00 and 4.00 p.m. (Fig. 2). The decrease in the the increase in photon fluence rate in blue light. A a rule, production rates before noon may have been due to tempo­ the photosynthetic activity increased more in the apex and rary clouds (Fig. 3) which cannot, however, explain the cortex tissues than in the base, which on the whole displayed duration of the decline. The decrease was most pronounced very low activities with high coefficients of variation (Ta­ for algae living close to the surface, where the photon ble 3 and 4). The effect of increase in photon fluence rate fluence rate is higher than at the incubation depth (3.5 m). wa distinct for the red algae both in summer and in winter. The high photon fluence rate at the surface may cause The adaptive role of the phycobiliprotein for the red algae photoinhibition (Powles 1984), and this rhythmic daily was emphasized by the fact that under the low photon phenomenon may cause physiological acclimatization, which fl uence rate their photosynthesis was always highest in is reflected as bimodal primary production for Cladophora green light. However, under the higher photon fluence rate, glomerata and Pilayella littoralis, even when the algae are the photosynthesis was highest in blue light, indicating the incubated in lower irradiance (Fig. 2; Falkowski & LaRoche importance of chlorophyll a as a light harvesting pigment 1991). The specific production rates were highest for the (Tables 3 and 4). light adapted C. glomerata [highest measurement 12.8 �g C Our observations roughly correlate with the action spec­ (mg total C)-1 h-1 at 4.00 p.m.]. At its maximum, the produc­ tra examined in different groups of algae (cf. Liining & tion rate of P. littoralis was close to that of C. glomerata, but Dring 1985). The green algae generally had their production especially at times when the photon fluence rate was lower, peaks in blue and red light, the red algae in the green light, its production rate was lower than those of the other whereas the brown algal species were generally indifferent filamentous algae. The specific production rates of the to light quality (Tables 3 and 4). As an exception from this shade adapted Ceramium tenuicorne and Cladophora principle, Urospora penicillifo rmis, when incubated under rupestris were constant through the day, as long as there was the weaker light in winter, seemed to be independent of the enough light for photosynthetic activity. C. tenuicorne light colour. Regardless of their morphology or pigment reached its highest rate [5.8 �g C (mg total C) -1h-1 ] at 2.00 components, many species had their production peaks under p.m. when the photon fluence rate at the incubation depth the higher photon fluence rate (18 �mol photons m-2s-1 ) was 260 �mol photons m-2s-1 • This coincides well with the

Acta Phytogeogr. Suec. 78 92 E. Leskinen et al.

results of Wallentinus ( 1978), who measured the saturation (10 and 18 �mol photons m-2s-1 ). Both the dark-adapted level for littoral C. tenuicorne to be about 220 �mol photons algae in winter, and the light-adapted algae in summer had m-2s-1 in mid-summer. a higher photosynthetic activity when the photon fl uence The level of the specific production rate of Fucus rate was increased from 10 to 18 �mol photons m-2s-1 • The vesiculas us was about 0.5 �g C (mg total C)-1 h-1 • The difference between the rates of the summer and winter production rate wa usually highest in the apical part of the specific production was small, partly due to higher chloro­ thallu and in the wing, and lowest in the base (Fig. 2) as phyll contents in winter. shown in earlier studies in the northern BalticSea (Guterstam et al. 1978, Kairesalo & Le kinen 1986). The low rates for 3. The production measurements under the different spectral the fucoid base are due to the high proportion of unproduc­ ranges correlated with the action spectra of green, brown and tive medulla tissue in the base. The cortex is, on the con­ red algae. This partly explains why the algae studied live in trary, highly productive, occasionally exceeding the pro­ certain light environments. The reasons for the algal species duction rates of the apical thalli of F. vesiculosus (Fig. 2). to inhabit the northern Baltic littoral in different times of the The highest specific production rates for the cortex in the year and at different habitat are, however, manifold, laboratory experiments were 0.9 �g C (mg total C)-1 h-1 (red including both biotic and abiotic factors. light, 18 �mol photon m-2s-1 , 15 oc; Table 3), and 1.3 �g C (mg total C)-1 h-1 in the measurements in situ (Fig. 2). 4. Most species showed bimodality in their photosynthetic The specific production rate of Furcellaria lumbricalis activity in situ. The phenomenon was clearest in the and Phyllophora truncata levelled at a rate of about 0.7 �g filamentou algae living close to the surface. The coarser C (mg total C)-1 h-1 at the photon fluence rate of 120 �mol algae with a lower production rate appeared to reach their photon m-2s-1 , at 10.00 a.m. (Fig. 2). In nature, both algae saturation level duri ng the highest photon fluence rates. The inhabit shaded places or live deeper down in low light highest photon fluence rates appeared to have an inhibitory intensities. Wallentinus ( 1978) measured the saturation level effect on the production of the shade-adapted red algae. of F. lumbricalis to be about 100 �mol photons m-2s-1 and that of P. truncata less than 100 �mol photons m-2s-1, with 5. The specific production rates of Fucus vesiculosus were slight changes depending on the time of the year. In her highest in those parts that are most exposed to light in nature: tudy, P. truncata in spring was very sensitive to higher the apical parts and the wing, both with bimodal activities light intensities resulting in photoinhibition, when the pho­ during the day. The lowest rates were measured in the base, ton fluence rate was over 100 �mol photons m-2s-1 • whereas the artificially detached basal cortex was highly Photoinhibition was evident for P. truncata also in our productive. results. Contrary to the results of Wallentinu (1978), there wa a light depre sion in the production rate of these ublittoral algae after the morning peak. The saturation level was, however, soon reached again. Acknowledgements. We would like to thank Prof. Inger Wallentinus, teacher at the course on macroalgal eco­ phy iology, arranged by the Nordic Collegium for Marine Biology in 1987, who inspired us in this study. Our thanks Conclusions are due to Ph.D. Timo Kairesalo and Prof. Eva-Mari Aro for their critical reading of the manuscript, and we are indebted 1. In all experiments, the level of primary production was to the students participating in this work at field courses in mostly affected by thallus morphology. Highest specific Baltic ecology at the Tvarminne Zoological Station. The production rates were measured for the filamentous species; Tvarminne Zoological Station provided us with excellent opportunistic algae that annually colonize the different litto­ working facilities, and the 'Waiter and Andree de Nottbeck' ral habitats. The perennial algae are corticated and leathery Foundation financed our work. in their life form. They are restricted to the sublittoral zone, due to scouring by ice in the hydrolittoral, and desiccation during the annual periods of low-water level. Thus, the perennial algae have a low saturation level for light, and the specific primary production rates measured were about 10- 15 %of those of the filamentous algae.

2. In the laboratory experiments, the production rates of the algae were as high as about half the rates measured for the diurnal experiment in situ, although the highest photon fluence rate in situ (259 �mol photons m-2s-1 ) was more than ten to twenty times higher than that in the laboratory

Acta Phytogeogr. Suec. 78 Primaryproduction of macroalgae 93

References Kirk, J.T.O. 1983. Light and photosynthesis in aquatic ecosystems. -Cambridge University Press, Cambridge. 40 1 pp. Littler, M.M. & Littler, D.S. 1980. The evolution of thallus form Aertebjerg Nielsen, G. & Bresta, A.-M. 1984. Guidelines for the and survival strategies in benthic marine macroalgae: Field and measurement of phytoplankton primary production. - The laboratory tests of a functional form model. - Am. Nat. 116: Baltic Marine Biologists, Publ. 1 (2nd ed.): 1-23. 25-44. Back, S., Collins, J.C. & Russell, G. 1991. Aspects of the LUning, K. & Dring, M.J. 1985. Action spectra and spect al reproductive biology of Fucus vesiculosus from the coast of � quantum yield of photosynthesis in marine macroalgae w1th SW Finland. - Ophelia 34: 129-141. thin and thick thalli. - Mar. Biol. 87: 1 19-129. Du Rietz, G .E. 1932. Zur Vegetationsokologie der o tschwedisch­ Marker, A.F.H., Nusch, E.A., Rai, H. & Riemann, B. 1980. The en KUstenfel en. - Beiheft. Bot. Centralbl. 49. measurement of photosynthetic pigments in freshwaters and Engelmann, T.W. 1893. Farbe und Assimilation. - Bot. Zeitung standardization of methods: Conclusions and recommendations. 41: 1-29. -Arch. Hydrobiol. Beih. Ergebn. Lirnnol. 14: 91-106. Falkowski, P.G. & LaRoche, J. 1991. Acclimatization to spectral Niemi, A. 1975. Ecology of phytoplankton in the Tvarminne area, irradiance in algae. - J. Phycol. 27: 8- 14. SW coast ofFinland. ll. Primary production and environmental Guterstam, B., Wallentinus, I. & Iturriaga, R. 1978. In situ primary conditions in the archipelago and the ea zone. - Acta Bot. production of Fucus vesiculosus and Cladophora glomerata. Fenn. 105: 1-73. - Kieler Meeresforsch., Sonderh. 4: 257-267. brsted, A.S. 1 844. De regionibus marinus. Elementa topographiae Hallfors, G., Kangas, P. & Lap alainen, A. 1975. Littoral benthos p historico naturalis freti Oresund. - Hauniae, Diss. inaug. 90 of the northern Baltic Sea. 3. Macrobenthos of the hydrolittoral pp. belt offilamentous algae on rocky shores in Tvarminne. - Int. Powles, S.B. 1984. Photoinhibition of photosynthesis induced by Revue Ges. Hydrobiol. Hydrogr. 60: 313-333. visible light. - Ann. Rev. Plant Physiol. 35: 15-44. Hallfors, G., Niemi, A., Ackefors, H., Lassig, J. & Leppakoski, E. Ramus, J. 1983. A physiological test of the theory of complementary 1981. Biological oceanography. - In: Voipio, A. (ed.) The chromatic adaptation. Brown, green and red seaweeds. - Baltic Sea. Elsevier, Amsterdam, Else vier Oceanography Series ll. J. Phycol. 19: 173-178. 30: 219-274. Russell, G. 1985. Recent evolutionary changes in the algae of the Jansson, A.-M., Kautsky, N., von Oertzen, J.-A., Schrarnrn, W., Baltic Sea. - Br. Phycol. J. 20: 87- 104. Sjostedt, B., von Wachenfeldt, T. & Wallentinus, I. 1982. - A Salemaa, H. 1987. Herbivory and microhabitat preferences of joint study by the BMB phytobenthos group. Contr. Asko Lab. !do tea spp. (Isopoda) in the northern Baltic Sea. - Ophelia 27: Univ. Stockholm 28: 1-96. 1-15. Jansson, B.-O. & Wulff, F. 1977. Ecosystems analysis of a shallow Strickland, J.D.H. & Parsons, T.R. 1972. A practical handbook of sound in the northern Baltic proper. A joint study by the Asko seawater analysi . -Bull. Fish. Res. Bd Can. 167: 1-310. group. - Contrib. Asko Lab. Univ. Stockholm 18: 1-160 . . Tuomi, J., Siren, S., Niemela, P., Jive salo, H. & Jorrnalainen, V. Kairesalo, T. & Leskinen, E. 1986. Measurements of metabolic 1 989. Within-plant variation in phenolic content and toughnes activities within a Baltic Fucus vesiculosus community: The of the brown alga Fucus vesiculosus L. - Bot. Mar. 32: 505- contribution of fo uling microalgae and grazers. - In: Evan , 509. L.V. & Hoagland, K.D. (eds.) Algal biofouling. Elsevier, Wrern, M. 1952. Rocky-shore algae in the Oregrund Archipelago. Amsterdam, pp. 30 l-312. - Acta Phytogeogr. Suec. 30: 1-298. Kangas, P., Autio, H., Hallfors, G. Luther, H., Niemi, A. & Wrern, M. 1965. A vista on the marine vegetation. - Acta Salemaa, H. 1982. A general model of the decline of Fucus Phytogeogr. Suec. 50: 13-28. vesiculosus atTvarrninne, south coastofFinland in 1977- 1981. W allentinus, I. 1976. Productivity studies on Cladophora glomerata -Acta Bot. Fenn. 118: 1-27. (L.) KiHzing in the northern Baltic proper. - In: Persoone, G. Kautsky, N., Kautsky, H., Kautsky, U. & Wrern, M. l 986. Decreased & Jaspers, E. (eds.) Proc. lOth Europ. Symp. Mar. Bioi., depth penetration of Fucus vesiculosus (L.) since the 1940's Ostend, Belgium, Sept. 1 7-23, 1975. Universa Press, Wetteren. indicates eutrophication ofthe Baltic Sea. - Mar. Ecol. Prog. Vol. 2: 63 1-651. Ser. 28: 1-8. Wallentinus, I. 1 978. Productivity studies on Baltic macroalgae. ­ Kautsky, H., Kautsky, L., Kautsky, U. & Lindblad, C. 1992. Bot. Mar. 21: 365-380. Studies on the Fucus vesiculosus community in the Baltic Sea. Wallentinus, I. 1979. Environmental infl uences on benthic -Acta Phytogeogr. Suec. 78: 33-48. rnacrovegetation in the Trosa-Asko area, northern Baltic pro­ King, R.J. & Schrarnrn, W. 1976. Photosynthetic rates of benthic per. II. The ecology of macroalgae and submersed phanerogams. marine algae in relation to light intensity and seasonal variations. - Contr. Asko Lab. Univ. Stockholm 25: 1-210. -Mar. Biol. 37: 215-222.

Acta Phytogeogr. Suec. 78

Effects of ferry traffi c on the metal content of Fucus vesiculosus in the 0 Aland archipelago, northern Baltic Sea

Olof Ronnberg, Torolf 6stman & Kaj Actjers

Abstract Ronnberg, 0., Ostman, T. & Adj ers, K. 1 992. Effects offerry traffic on the metal content of Fucus vesiculosus in the A land archipelago, northern Baltic Sea -Acta Phytogeogr. Sue c. 78, Upp ala. ISBN 91-72 10-078-8.

Wash effects of ship ' traffic (car ferries) on the contents of Fe, Zn and Cu in the brown seaweed Fucus vesiculosus L. were studied in the archipelago of Aland, SW Finland, in June-September 1988. Measurement were made on growing tip and basal parts of Fucus specimens from a semi­ exposed reference locality and from two localities exposed to a well-frequented ferry route. The contents ofFe decreased regularly towards autumn, and were 2-3 times higher in growing

tips than in old basal parts of Fucus. Significantly higher contents (p < 0.01) were generally measured in samples from localities close to the route. The zinc contents fluctuated slightly during the study period. In general the contents were 1.5 times higher in basal parts than in growing tips. In contrast to the Fe-contents, the recorded Zn-contents throughout the study were significantly

higher (p< 0.01) in Fucus from the reference locality. The contents of Cu, both in young and old parts, were usually low and fluctuated irregularly during the study period. No significant differences could be proved between the localities. The results indicate that changed environmental conditions caused by ships' traffic can alter the availability of many metals in shallow archipelago waters in the Baltic Sea.

Keywords: Brown alga; Copper; Iron; Wash effect; Zinc.

A A Department of Biology & Huso Biological Station, bo Akademi University, SF-20500 bo, Finland.

Introduction load along shores fringing a frequented ferry route. It is well documented that macroalgae can concentrate Studies of the impact of regular ferry traffic on marine biota metal ions from the surrounding water (see Phillips 1990, in Baltic archipelagoes have mainly been focused on effects for a review). The algae reflect the ambient, dissolved of the artificial wave action on littoral communities concentrations of metals, and provide a time-integrated (Fagerholm 1975, 1978, Ronnberg & Lax 1980, Ronnberg picture of metal availability (Levine 1984, Phillips & Segar 1981, 6stman & Ronnberg 1991). Close to ferry routes the 1986). The uptake of metals is affected by the metabolic hydrolittoral belt of annual filamentous algae is lifted higher processes ofthe algae and influenced by physical conditions up the shore, while the sub littoral vegetation of the perennial in the environment (Levine 1984, Phillips 1990). brown alga Fucus vesiculosus L. is forced down to a deeper The aim of the present study was thus to investigate how level. At the same time the biomass and number of species heavy ferry traffic through a shallow archipelago area influ­ of epilithic macroalgae and associated invertebrates are ences the contents of the metals iron (Fe), zinc (Zn) and reduced. The main reasons for these changes are considered copper (Cu) in Fucus vesiculosus, the only large brown to be the shoreward transport of sediments by ships' waves seaweed occurring in the brackish coastal waters of SW in shallow water and the increased eroding effect of waves Finland. The three studied elements are essential micro­ and ice (Ronnberg 1981). After mild winters with little or no nutrients and often referred to as trace metals. They may ice a temporary Fucus belt can be established in the hydro­ limit algal growth if concentrations in the water are too low littoral (Fig. 1). According to a recent study (Ronnberg et al. and cause toxic effects at higher concentrations (Lobban et 1991) Fucus also grows faster and has a heavier epiphytic al. 1985).

Acta phytogeogr. suec. 78 96 0. Ronnberg et al.

localities at a distance of 530 m (locality 2) and 220 m (locality 3) from the ferry route respectively (Fig. 2). In the laboratory the samples were washed, cleaned from detach­ able algal epiphytes and sessile animals and dried at 60 oc for 24 h. The elements Fe, Zn and Cu were analysed using a Spectra Span IIIB Direct Current Plasma atomic emission spectrometer. The ashing procedure and the wave-lengths and detection limits used are described by Ronnberg et al. ( 1 990). All concentrations were related to Fucus dry weight. The differences in metal content in time and space were analysed statistically by means of two-way ANOV A. The SNK-test (Sokal & Rohlf 1969) was used to assess signifi­ cant differences between the localities.

Results

The Fe-content in Fucus tips from the three studied localities was highest in June and decreased regularly towards autumn (Fig. 3 A). This was especially the case in tips from the two localities exposed to the ferry route. With the exception of locality 2 in September, significantly higher values were recorded at the localities facing the route. The differences between localities 2 and 3 were generally small; only in September did Fucus tips from locality 3 have a significantly higher Fe-content than tips from locality 2. In old basal parts of Fucus the Fe-content was generally 2-3 times lower, and the variation between the localities was smaller than in growing tips (Fig. 3 B). In June the values were significantly Fig. 1. A luxuriant hydrolittoral vegetation of Fucus vesiculosus higher at both locality 2 and 3 compared to the reference close to a ferry route in the Aland archipelago after three almost ice­ locality, in September only at locality 3. free winters. Due to the frequent wash from passing ferries this The Zn-content in growing tips and old basal parts of the temporary Fucus belt can survive the period of low-water level in Fucus fronds also showed a tendency to decrease towards spring. Stora Stegshir, April 23, 1991. autumn (Fig. 4 A-B). In contrast to Fe the Zn-content was significantly higher at the reference locality compared to the localities close to the route. The Cu-content was lower than those of Fe and Zn, and fluctuated between 0.004 and 0.012 mg g-1 Fucus dryweig ht both in tips and basal parts (Fig. 5 A-B). Except for tips from Material and Methods locality 3 the values fluctuated irregularly during the study period and showed, like the other studied metals, a tendency The study was performed at the fairway through the to decrease in September. Significant differences between A archipelago of land, SW Finland, used by ferries on the the reference locality and a fairway locality (locality 3) A Finland-Sweden line calling at the land Islands (Fig. 2). could be proved only for basal parts in July. In September During the study period in 1988 eight ferries passed through also basal parts from locality 3 had a significantly higher (p the area every day. The salinity of the surface water in the < 0.05) Cu-content than corresponding parts from locality 2. area is 6-7 %o, and the sea is normally ice-covered for about Seasonal variations and variations between localities were 70-80 days per year. Tides are practically absent but, generally proved significant (p < 0.01) for all the studied depending on weather conditions, the water level can deviate metals. An exception was the variation in Cu-content in up to 1 m from the mean. A general description of the area Fucus tips, where only a significant seasonal variation (p < is given by Ronnberg (1981). 0.01) existed. In June-September 1988 three replicate samples (30 g fresh weight each) of young vegetative tips and old basal parts of the permanently submerged sublittoral Fucus vesiculosus were collected monthly from the same depth (about 2 m) at a semi-exposed reference locality and at two

Acta Phytogeogr. Suec. 78 Effe cts of fe rry trafic on Fucus vesiculosus 97 f

0 1 km

BALTIC PROPER

� �

(l"V

. 0�.

Fig. 2. The study area in the Aland archipelago, SW Finland, with sampling localities for Fucus vesiculosus. The olid line shows the ferry route through the area.

Discussion contents at our localities were 2-3 times higher in growing tips than in old basal parts throughout the study. At the reference locality the contents of Fe and Cu in Fucus An important reason for the high Fe-content in Fucus were slightly higher, and those of Zn lower, than at corre­ close to the ferry route is probably the mobilization of iron sponding localities in the outer archipelago of Stockholm from bottom sediments by the strong artificial turbulence (Forsberg et al. 1988). The decreasing contents of the stud­ caused by passing ships (Fagerholm et al. 1991), and the ied metals in late summer agree well with other observa­ ability of ships' waves to transport sediments from deeper tions from the Aland archipelago (Ronnberg et al. 1990). bottoms towards the shore (Ronnberg 1981). Rice & Lapointe They also coincide with the period of greatest increase in (198 1) showed that the content of Fe in the green alga Ulva length of vegetative Fucus shoots in the area (Ronnberg et fa sciata Delile increased with increasing nitrogen content. al. 1991; 1992), and the decrease could then be regarded as However, in our study area, the nitrogen content in Fucus 'dilution by growth'. tips was significantly higher at the reference locality than at According to most studies (Phillips 1990) metal concen­ localities affected by ships' traffic (Ronnberg et al. 1991). trations are generally higher in older parts of macroalgae An explanation of this discrepancy is probably the fact that and lower in fast-growing tips. Also from the Stockholm Fe is strongly associated with fine particulate material which archipelago Forsberg et al. (1988) reported significantly is difficult to eliminate by washing from the algal surface higher contents of Fe and Zn in older thallus parts than in (Phillips 1990). Also a rich growth of epiphytes, especially growing tips. In contrast to these observations, the Fe- of Pilayella littoralis (L.) Kj ellm. and Elachista fucicola

Acta phytogeogr. suec. 78 98 0. Ronnberg et al.

A A 0.8 0.5 ** D loc. l D loc. l ** loc. c=::::J 2 loc. 2 0.4 • loc. 3 I 0.6 I....._ ** � � "0 "0 0.3 ** .::9 .::9 0 0.4 u.. c: bJ) bJ) 0.2 E E 0.2 0. 1

0.0 0.0 June July Aug. Sept. June July Aug. Sept. B 0.8 B 0.5 loc. I loc. D ** D loc. loc. 2 ** ** 2 • loc. 3 0.4 c=::::J loc. 3 0.6 • I,.-.. I � � "0 0.3 "0 ** 0.4 .::9 .::9 ** c: 0 N u.. c::::=::J 0.2 bJ) bJ) E E 0.2 0. 1

0.0 0.0 June July Aug. Sept. June July Aug. Sept.

Fig. 3. Contents of Fe (mean ± SE) in vegetative tips (A) and basal Fig. 4. Contents ofZn (mean ± SE) in vegetative tips (A) and ba al parts (B) of Fucus vesiculosus in the vicinity of a ferry route in the parts (B) of Fucus vesiculosus in the vicinity of a ferry route in the Aland archipelago, June-Sept. J 988. Horizontal bar indicate Aland archipelago, June-Sept. J 988. Horizontal bars indicate ignificant differences between the reference locality (locality 1) significant differences between the reference locality (locality l) and the localities exposed to the route (*= p < 0.05, **= p < 0.0 I). and the localities exposed to the route (*= p < 0.05, **= p < 0.01 ).

A 0.02 �------, D loc. l loc. 2 (Veil.) Aresch., may greatly enhance the Fe-content loc. � • 3 (Forsberg et al. 1988). The complete removal of epiphyte � "0 (e.g. Elachista) i often difficult, and they can thu con­ .::9 ::I 0.01 tribute to the high Fe-contents in Fucus from the localities u bJ) expo ed to the route where the epiphyte biomasse , e pe­ E cially in early summer, were 3-5 times higher than at the reference locality (Ronnberg et al. 1991). Zinc was the only studied metal that showed lower con­ 0.00 June July Aug. Sept. tents in Fucus from the locations exposed to the traffic throughout the study. Uptake ofZn in seaweeds is by active B 0.02 transport (Lobban et al. 1985). The accumulation of the D loc. l metal is increased by higher nitrogen contents, because the loc. 2 I uptake rate is dependent on the availability of organic � "0 nitrogen ligands within the algal cells (Rice & Lapointe .::9 ::I 1981). This agrees with the earlier mentioned fact that the u 0.0 1 bJ) highest nitrogen contents were measured in Fucus from the E reference locality (Ronnberg et al. 1991). According to Forsberg et al. (1988) filamentous epiphytes accumulate much lower amounts of Zn than Fucus vesiculosus. The 0.00 rich, hardly removable, epiphyton close to the route may June July Aug. Sept. thus contribute to the lower Zn-contents at localities 2 and 3. Fig. 5. Contents ofCu (mean ± SE) in vegetative tips (A) and basal Cu is apparently taken up by seaweeds by active transport part (B) of Fucus vesiculas us in the vicinity of a fe rry route in the and accumulated in the physodes in the cells (Smith et al. Aland archipelago, June-Sept. 1988. Horizontal bars indicate 1986). Despite the fact that the Cu-content in Fucus has ignificant differences between the reference locality (locality 1) been shown to increase at wave-exposed sites (Forsberg et

and the localities expo ed to the route (*= p < 0.05, **= p < 0.01). al. 1988) and by scavenging from surface sediments (Luoma

Acta Phytogeogr. Suec. 78 Effects of fe rry traffic on Fucus vesiculosus 99

et al. 1 982), the traffic did not seem to have any effect on the Phillip , D. J. H. 1990. U e of macroalgae a monitors of metal Cu-content in Fucus in the study area. According to the levels in e tuaries and coastal water . -In: Furness, R. W. & shipowners the hulls of the ferries were not treated with Rainbow, P. S. (eds.). Heavy metal in the marine environment. antifouling paints containing copper or other heavy metals CRC Pres , Florida. pp. 81-99. Phillips, D. J. H. & Segar, A. D. 1986. U e of bio-indicator in as active components. monitoring conservative contaminants: Programme design It may be concluded that, despite possible errors caused imperative . -Mar. Poll ut. Bull. 17: 10-17. by a heavy epiphyton, Fucus vesiculosus eems usable as a Rice, D. L. & Lapointe, B. E. 1981. Experimental outdoor tudie bio-indicator of the availability of Fe and Zn, and probably with Ulvafasciata De1ile. II. Trace metal chemi try. -J. Exp. of other trace metals as well, in the changed environmental Mar. Bioi. Ecol. 54: 1-1 1. conditions (e.g. increased water movements and turbidity) Ronnberg, 0. 1981. Traffic effects on rocky-shore algae in the around well-frequented ships' routes through sheltered ar­ Archipelago Sea, SW Finland. - Acta Acad. Abo. (Ser. B), chipelagoes of the Baltic Sea. 41(3): 1- 87. Ronnberg, 0. & Lax, P.-E. 1980. Influence of wave action on morphology and epiphytic diatom of Cladophora glomerata Acknowledgements. We should like to thank Drs. Leo Harju, (L.) Kiitz. - Ophelia, Suppl. 1:209-2 18. Abo Akademi University, and Marianne Pedersen, Uppsala Ronnberg, 0., Adj ers, K., Ruokolahti, C. & Bondestam, M. 1990. University, for helpful suggestions, and Mr. Christopher Fucus vesiculas us as an indicator of heavy metal availability in Grapes, B.A., Abo Akademi University, for checking the a fish farm recipient in the northern Baltic Sea. - Mar. Pollut. English. Financial support was provided by the Archipelago Bull. 21: 388-392. Project of the Nordic Council of Ministers. Ronnberg, 0., Adj ers, K., Ruokolahti, C. & Bondestam, M. 1992. Effects of fi h farming on growth, epiphyte and nutrient content of Fucus vesiculosus L. in the Aland archipelago, northern Baltic Sea. - Aquat. Bot. 42: 109- 1 20. Ronnberg, 0., bstman, T. & Adj ers, K. 1991. Fucus vesiculosus as References an indicator of wash effects of ship ' traffic. - Oebalia 17( 1) suppl.: 213-222. Fagerholm, H.-P. 1975. The effects of ferry traffic on the rocky Smith, K. L., Hann, A. C. & Harwood, J. L. 1986. The ubcellular shore macrofauna in the southern Aland archipelago: 1. The localisation of absorbed copper in Fucus. - Physiol. Plant. 66: Cladophora zone. - Merentutkimuslait. Julk./Havsforsk­ 692-698. ning inst. Skr. 239: 33 1 -337. Sokal, R. R. & Rohlf, F. J. 1969. Biometry.- W.H. Freeman & Fagerholm, H.-P. 1978. The effects of ferry traffic on the rocky Company, San Franci co. 776 pp. shore macrofauna in the southern Aland archipelago in the northern Baltic. 2. The Fucus zone (a quantitative study). - Kiel. Meere forsch. Sonderh. 4: 130- 137. Fagerholm, H.-P., Ronnberg, 0., bstman, M. & Paavilainen, J. 1991. Remote sensing asse sing artificial di turbance of the thermocline by ships in archipelagoes of the Baltic Sea with note on some biological consequences. - International Geoscience and Remote Sensing Symposium Dige t 2: 377- 380. Forsberg, A., Soderlund, S., Frank, A., Petersson, L. R. & Pedersen, M. 1 988. Studies on metal content in the brown seaweed, Fucus vesiculosus, from the archipelago of Stockholm. - Environ. Pollut. 49: 245-263. Levine, H. G. 1984. The use of seaweeds for monitoring coastal waters.- In: Schubert, L. E. ( ed.) Algae as ecological indicators. Academic Press, London. pp. 189-2 10. Lobban, C. S., Harrison, P. J. & Duncan, M. J. 1985. The physiological ecology of seaweeds. - University Pre s, New York. 242 pp. Luoma, S. N. 1990. Processes affecting metal concentrations in estuarine and coastal marine sediments. - In: Fume s, R. W. & Rainbow,P. S. (eds.) Heavymetalsinthe marineenvironment. CRC Press, Florida. pp. 51-66. Luoma, S. N., Bryan, G. W. & Langston, W. J. 1982. Scavenging of heavy metal from particulates by brown seaweed. - Mar. Pollut. Bull. 13: 394-396. b tman, M. & Ronnberg, 0. 1991. Effects of ships' waves on rock­ pools in the Aland archipelago, northern Baltic Sea. - Sarsia 76: 125-1 32.

Acta phytogeogr. suec. 78

0 Floristic aspects of the coastal inlet Inre Ve rkviken, northern Aland

Hans Mathiesen and Lisbeth Mathiesen

Abstract Mathiesen, H. & Mathie en, L. 1992. Floristic aspect of the coa tal inlet Inre Verkviken, northern Aland -Acta Phytogeogr. Suec. 78, Upp ala. ISBN 91-7210-078-8.

Inre Verkviken, northern Aland (60°20'N, 20°00'E), is connected to the Gulf ofBothnia by a canal. By the input of brackish water (5-6 %o S) Inre Verkviken represents a merornictic coastal inlet. The inlet is only weakly affected by man and is thus a good reference area with a remarkable nature worthy of conservation. The submerged vegetation was well-developed, and over large areas of the inlet it extended to a depth of 4-5 m, with a maximum depth of 6-6.5 m. Several of the katharobic associations were common in Inre Verkviken, and the dominating species were Potamogeton perfoliatus, P. pectinatus and Myriophyllum sibiricum. The innermost area is shallow (3.5 m); a typical semi-enclosed brackish inlet ('flada' in Swedish). The soft bottom was, in contrast to the other areas, characterized by reed belts and dense meadows of charophytes together with Najas marina. The green alga Cladophora glomerata was common, not only here but all over the inlet. In the adjacent sound, the benthic macroalgae were represented by Hildenbrandia rubra, Lithoderma subextensum, Ectocarpus siliculosus and Enteromorpha spp. On bottoms with gravel a sparse community of Tolypella nidifica - Najas marina occurred. On the eastern, steep rocky shore of the central part at a depth of 2-6 m a carpet of Cladophora aegagropila repre ented an algal community typical for the Gulf of Bothnia. The gently sloping rocky bottom with boulders on the western shore wa characterized by a noteworthy loo e-lying community of Va ucheria dichotoma (down to 6.5 m), Drepanocladusfluitans and Monostroma balticum (down to 4.5 m). Fucus vesiculosus wa repre ented in the outer part of the inlet both as a loo e-lying soft bottom community and a an epilithic community between large boulder . Epiphytes on Fucus were Ceramium tenuicorne, Ectocarpus siliculosus, Chorda filum and Cladophora glomerata. Chormophytes here were Batrachium baudotii, Myriophyllum sibiricum, Potamogeton perfoliatus, P. pectinatus, Ruppia maritima and Zannichelliapedunculata. Six of the important species of the Baltic katharobic associations were not found in the inlet: Batrachium circinatum, Littorella uniflora,Myrio phyllum spicatum, M. verticillatum, Zannichelliamajor and Ceratophyllum demersum. Since they grow in most coastal waters of the Baltic area with similar salinities their absence cannot only be due to salinity conditions.

Keywords: Charophytes; Cladophora aegagropila; Gulf ofBothnia; Monostroma balticum; Vaucheria dichotoma.

Institute of Biology, Department of Plant Ecology, University of Aarhus, Nordlandsvej 68, DK-8240 Risskov, Denmark.

Introduction

Detailed floristic studies on the macrobenthic flora in the several benthic algae and submerged chorrnophytes were Baltic coastal areas have significantly contributed to the subjectto critical examination by Luther (1951a, 1951b) and literature dealing with the autecology of species widely Wrem(1 952). Wrem(1 965) stressed the importance of the distributed within the Baltic Sea. The salinity tolerances of salinity gradient along the Swedish coasts to the macrobenthic

Acta Phytogeogr. Suec. 78 102 H. Mathiesen & L. Mathiesen

INRE VERKVIKEN

N l

Depth ------5m ---10m ·· .. ··15m ...... 20m

500 m

Fig. l. Location maps and map of lnre Verkviken, showing the six sampling areas.

algal flora; he also emphasized the importance of fl uctua­ Study area tions in salinity. Luther (1951a) called attention to the importance of lack of large salinity fluctuations, when he Inre Verkviken, at Saltvik, northern Aland (60°20' N, 20°00' compared the distribution of the macrophytic flora in E) is a long, narrow, fj ord-like coa tal inlet, 2.8 km long, Pojoviken with that of a Danish Kattegat inlet, highly and 20 m deep at its deepest point (Fig. 1). The inlet is influenced by alinity fluctuations, which resulted in a connected to the Gulf of Bothnia via a 200 m long, 3-4 m horizontally more narrow di tribution of pecies in the latter wide and approximately 1 m deep canal, which ha ilted up area (Rander Fj ord; see Mathiesen & Nielsen 1956). on many occasions in the twentieth century. Without the In studies dealing with the eutrophication of the Baltic subsequent clearing of the canal Inre Verkviken would now coa tal waters the floristic aspects have acquired a scientific be an inland lake. Through the often sporadic introduction a well as a practical meaning (e.g. Wallentinu 1979, of brackish water, Inre Verkviken represent an interesting Hallfors et al. 1987). Obviously, it is of fu ndamental impor­ extended stage of development somewhere between a sea tance to learn to distingui h between ome occasional fl uc­ inlet and an inland lake (cf. Lindholm 1982, Lindholm et al. tuation and the pronounced changes of vegetation caused 1987). Inre Verkviken's water hed covers an area of only 5 by human influences (Mathiesen 1980). Of great present km2 and the supply of freshwater is thus not very large; land interest are detailed floristic examinations carried out in runoff is less than the amount of brackish water transported waters, which in the near future might serve as reference into the inlet from the Gulf of Bothnia (especially with areas and/or have a remarkable nature worthy of conserva­ northerly winds). The salinity of Inre Verkviken is rather tion. stable, ea. 5 with minor freshwater influence in the A %o, Our studies of the inlet Inre Verkviken, land, were south, whereas in the north there is some influence from the initiated as floristic studies of the remarkable characean incoming sea water (salinity 5-6 %o, Lindholrn 1982). communities (Lindholm 1991). In addition, these vigorous The inlet is only weakly affected by man. The population beds of brackish water flora occurred in a coastal area with density i low, mostly consisting of houses for non-perma­ characteristic local stability of low salinity (cf. W rern 1965) nent living (Lindholm 1 982). The innermost part of the inlet and with rather clear water. Furthermore, this inlet includes is a soft bottom bay. Belts of reeds (Phragmites australis) a shallow-water area, a 'flada' in Swedish (cf. Lindholm et are common, and meadows of stonewort almost cover the al. 1989) and deeper areas, where the vegetation extends to area, dominated by Chara aspera and C. tomentosa. depths of more than 5 m. In addition, our floristic examina­ (Lindholm 1991). Further out, the western shores of the Inre tion of Inre Verkviken is part of a programme designed to Verkviken are changing into sandy stretches with shallow indentify different types of coastal vegetation only weakly water. Deeper-lying parts consist of mud bottoms, except in affected by human impact (Lindholrnet al. 1987). the botanically interesting area ofNorrsvedja-Grundet, area

Acta Phytog'eogr. Suec. 78 Floristic aspects of lnre Ve rkviken 103

Table 1. Species found in the re pective area of lnre Yerkviken, 4 (Fig. 1), where boulders occur. Otherwise the rocky shores northern Aland, July-August 1990 and 1991. 5 = common, 4 = are high and steep. The 114 m high Kasberget descend as a rather common, 3 = frequent, 2 = rather rare, 1 = rare, =occasional x vertical rock face to the deepest part of the inlet. and p = pilae marinae.

2 3 4 Taxa I Area 6

OSTOCOPHYCEAE: 2 5 5 2 2 Calothrix scopulorum (Webb. & Mohr) Born. & Flah. Material and Methods 2 2 3 Gloeotrichia natans (Hedwig) Rabenhor t X Gloeotrichia piswn (C. Ag.) Thuret The summer vegetation was tudied over periods of two Lyngbya p. 2 2 2 Rivularia atra Born. & Flah. X weeks in July-August, 1990 and 1991, respectively. The Tolypothrix sp. narrow, sheltered, 2.8 km long inlet was divided into six BA GIOPHYCEAE: areas, each with its own characteristic combination of macro­ 2 Ceramiwn tenuicorne (KUtz.) Wa:rn p p 2 2 phyte and thallophyte repre enting ten classes (Table 1 ). Hildenbrandia rubra (Sommerf.) Menegh. X Polysiphonia violacea (Roth) Spreng . . I. The vegetation consisted of 5 species of Charophyta 14 of

FUCOPHYCEAE: Chormophyta, 1 of Bryophyta, 1 of Lichenes and 32 of Chordafilum (L.) Stackh. I 2 macrocopic algae (cf. Cedercreutz 1947, Lindholm & I Ectocarpus siliculosus (Dillw.) Lyngb. p Ronnberg 1985). Fucus vesiculosus L. X I Lithoderma subextensum Wa:rn I The floristic surveys within the inlet were carried out Pilayella littoralis (L.) Kj ellm. p p p from a boat, and dredging was made with a rake introduced Sphacelaria radicans (Dillw.) C. Ag. p p p Stictyosiphon tortilis (Rupr. ) Reinke s. Ro env. p by Luther ( 1951a) or with a dredge for benthic macroalgae.

DIATOMOPHYCEAE: The abundance of the macrobenthic species was estimated Diatom in large colonies (different taxa) 4 4 2 4 according to a 5 degree abundance scale (Mathie en &

TRIBOPHYCEAE: Mathiesen 1976), viz. 5 =common, 4 =rather common, 3 = Vaucheria dirhotoma (L.) Martiu 2 2 frequent, 2 = rather rare, 1 = rare, x = occasional and p = Vaucheria sp. pilae marinae (loose-lying balls). More than 50 cross sec­ CHLOROPHYCEAE: tions including about 300 sampling sites were examined. Bolbocoleon piliferum N. Pringsh. X Complementary observations using a waterglass were made. Clzaeromorpha p. p 5 Cladophora aegagropila (L.) Rabenhor t p p The material was identified by using the following publi­ Cladophora glomerata (L.) KUtz. 4 5 2 3 cations: Hasslow 1931, 01 en 1944, Blindow & Krause Cladophora rupestris (L.) KUtz. p p p Enteromorpha ahlneriana Slid. I 1990 for charophytes; Cedercreutz 1934, Luther 1947, Han­ Enteromorpha intestinalis (L.) Link 2 I sen 1988, Hamet-Ahti et al. 1989, Moeslund et al. 1990 for Haematococcus ph11•ialis Flot. 4 2 Monostroma balticum (Wittr.) Witlr. 4 2 chormophyte . The Baltic Sea ha no tide and for the Mougeotia p. vertical zonation of the vegetation the terminology adopted Percursaria percursa (C. Ag.) Rosenv. by Wrern (1952) was used i.e. the geolittoral, hydrolittoral Rhizoclonium riparium (Roth) Harv. Spirogyra sp. and sublittoral belts. Zygnema sp.

CHAROPHYCEAE: Chara aspera Willd. 2 5 Chara canescens Lois. I 2 2 3 Chara globularis Thuill. X Vegetation Chara tomentosa L. 4 2 2

Tolypella nidifica (O.F. MUll.) A. Br X X Area 1 CHORMOPHYTA: Batrachiwn baudotii (Godron) F. Schultz 3 I This southern and innermost area (Fig. 1) is a ea. 3 m deep Calli1riche hermaphroditica L. X X X Eleocharis acicularis 2 2 2 (L.) Roemer & Schultes 'flada', the bottom of which consists of clay and sand. Chara Myriophyllum sibiricum Komarov. 4 2 3 4 2 Najas marina L. 4 4 2 2 3 2 species dominated the vegetation there (Table 1). Chara 5 I 2 2 Phragmires australis (Cav.) Steudel X X aspera could be seen as 30 m large beds from a depth of Potamogeto11 berchtoldii Fieber X 2 0. 1 m in open areas among the reeds. Within the rich fertile Potamogeton filiformis Pers. X Potamogeton pectinatus L. 4 3 3 4 vegetation the red coloured male globuli were conspicuou . Potamogeton perfoliatus L. 3 5 3 Outside the Phragmites belt, between 0.5 - 0.8 m, the rust­ Potamogeton pusillus sec. Dandy Taylor & X brown Chara tomentosa dominated large areas together Ruppia maritima L. Zannichellia pedunculata Reichenb. I with Najas marina. A few individuals of these two species Zannichellia repens Boenn. 2 X were also found together with Potamogetonpectinatus down BRYOPHYTA: to 1.8 m. The areas covered with Chara globularis and Drepanocladus fluitans (Hedw.) Warnst. 2 5 X C. canescens were always small. C. globularis occurred in LICHENES: cloud-like formations, often of great density. In contrast the Verrucaria maura Wahlenb. growth of the light green-grey C. canescens was sparse, and

Acta Phytogeogr. Suec. 78 104 H. Mathiesen & L. Mathiesen

it occurred together with species such as Potamogeton was growing up to 20 cm high as light green specimen in a filiformis and Najas marina. belt down to a depth of 2 m. Attached Cladophora aega­ Flowering species were characteristic on the bottoms of gropila covered the rock between 2 and 6 m. Continued sand or clay of the 'flada'. The deepest record of Potamogeton phycological studies with SCUBA-diving are recommended pectinatus in this area (by using a Luther-rake) was at 3.2 m, to obtain a more detailed picture of this vegetation. while living rhizomes and bulbils were found down to 3.4 m. Rare occurrence of Zannichellia re pens wa observed all over the inlet at the deep-water limit of the vegetation which Area 4 here was 3 m. Myriophyllum sibiricum (syn. M. exalbescens), the only Myriophyllum species occurring in the inlet was The western shore of area 4, known as the Norrsvedja­ rare in this part of the inlet (cf. Lindholm et al. 1 989). On the Grundet, was the most interesting in terms of the flora (Table sediment bottom with gravel Cladophora glomerata was 1 ). In this part of the inlet, the granite rocks were not covered dominant. It grew on Chara aspera as an epiphyte, with a with sediments and great boulders border the 20 m deep cover of diatoms (cf. Ronnberg & Lax 1980, Snoeijs 1989), central part. At the time of the investigations clear water and not only here, but all over the inlet. Gelatinous provided an excellent opportunity to study the benthic flora. tubeforrning diatoms were particularly common. In this Between 2 and 3 m below the water-line a widespread area Enteromorpha spp. were only seen in small patches. vegetation of Cladophora glomerata occurred, often loose­ lying. C. aegagropila mainly occurred as 0.5-2 cm large

balls,pilae marinae, together with C. glomerata, C. rupestris, Area 2 Rhizoclonium riparium, Spirogyra sp. and Chaetomorpha sp. (Table 1). In this sound (Fig. 1) with rocky slopes and gentle water Two other species of macroalgae were common in the movements there is a light sandy bottom with gravel. The loose-lying communities: Va ucheria dichotoma (at depths characean community was under these circumstances magni­ of 2-6.5 m) and Monostroma balticum (at depths of 1 .5-2.5 ficent, with all species of the area present (Table 1). The m). Va ucheria dichotoma was found in mass-occurrence middle part of the sound (1-2.3 m deep) was covered by a between 2.5 and 4.5 m in areas 4-5 (Table 1), and as deep as community dominated by Myriophyllum sibiricum. 5 m the species was still common together with a few plants The two crustaceous algae Hildenbrandia rubra and of Monostroma balticum. All over the inlet V. dichotoma Lithoderma subextensum (Wrem 19 49) were the innermost formed the deep water-limit of the vegetation with rare eo­ red and brown algae occurring in the southern part of the occurrence of Callitriche hermaphroditica. Living material

inlet. Hildenbrandia rubra occurred 0.5 m under the sum­ of V. dichotoma was still recorded at 6-6.5 m, while at 7 m mer-waterline and Lithoderma subextensum was found on only dead Va ucheria wa collected with the Luther-rake. stones from a depth of 2 m. The innermost isolated speci­ Also the watermoss Drepanocladus fluitans was growing men of Fucus vesiculosus, 30 cm high, was found under here, as loose-lying masses at depths between 2 and 4.5 m. some alder trees. During the two study periods Enteromorpha The biomass of the loose-lying communities at 2.5 m, spp. were seen only in a few, small patches; Enteromorpha dominated by Drepanocladus, in August 1990 varied be­ intestinalis was the most common species, but also tween 180 g and 600 g dry matter m-2.

E. ahlneriana was found. In the autumn of 1991 specimens The shallow-water vegetation, forming mats and belts of Enteromorphaocc urred in belts on the steep, rocky cliffs along the shore line, consisted of Chara aspera, Cladophora on the eastern side of Inre Verkviken (Tore Lindholm pers. glomerata, Eleocharis acicularis and Zannichellia repens.

comm.). In the geolittoral zone, the community of Calothrix The biomass of dense shallow-water stands of C. aspera in scopulorum - Verrucaria maura increased in density com­ August 1991 varied between 100 and 500 g dry matter m-2. pared to in area 1, and Rivularia atra was common.

Areas 5 and 6 Area 3 These areas in the northern part of the inlet are connected to In the south of area 3 shores with gentle slopes occur, the Gulf of Bothnia by a canal. The water may flow either in whereas towards the north, steep rocky shores extend into or out of the inlet, depending on the prevailing winds and area 4. In the geolittoral zone, the vegetation was in­ hydro graphic factors. Here, the quantity and variety of algae creasingly dominated by a cover of Calothrixscopulorum ­ were the greatest in the inlet. Verrucaria maura. The rock pools at the upper border of the On the soft bottoms, there was a luxurious vegetation of shore-line were deep red in colour, due to the presence of the Fucus vesiculosus with air-bladders; male plants with re­ green alga Haematococcus pluvialis. ceptacles were recorded. The type of F. vesiculosus found Duri ng summer Cladophora glomerata was the domi­ here is commonly known as "crisp and proliferous Fucus" nant alga on all types of substratum in the inlet. In area 3 it (Wrern 1952) and could be seen in associations of20-30 m2.

Acta Phytogeogr. Suec. 78 Floristic aspects of Inre Verkviken 105

On the eastern steep rocky shores with boulders Fucus flora as indicators of the trophic status of coastal waters, vesiculosus plants were recorded from depths of 2-2.5 m. when describing the macrophyte vegetation. The vegetation Chorda filum, Ectocarpus siliculosus and 0.5-1 cm high in the semi-enclosed sea-inlet Inre Verkviken may be clas­ Ceramium tenuicorne were common epiphytes on the Fucus sified as katharobic (cf. Hallfors et al. 1987, pp. 126- 1 29). plant and at haded sites Polysiphonia violacea and Pilayella The katharobic elements were represented by Cladophora littoralis also occurred. Sp irogyra was found in mass-oc­ aegagropila and associated epiphytes such as Tolypothrix currence among Fucus and chormophytes and several spe­ sp. , Gloeotrichia natans and Rhizoclonium riparium. Hallfors cie of blue-green algae were present (Table 1). et al. (1987) quoting Hayren (1944, 1949) described the On sandy bottoms in this part of the inlet and at the deep­ Aegagropiletum benthonicum association composed of C. water limit of the vegetation the pilae marinae consisted of aegagropila, attached or forming loose-lying balls. These large amounts of Sphacelaria radicans (cf. Wcern 1945, balls, pilae marinae, were sparse, but typical, in Inre 1952) together with Cladophora spp., and associated spe­ Verkviken at depths between 4 and 6 m (see above). cies of the genera Pilayella, Ectocarpus, Stictyosiphon, Ceramium and Va ucheria (Table 1). Monostroma balticum Va ucheria dichotoma also occurred and large quantities of Vaucheria dichotoma were found (Table 1). Va ucheria dichotoma was one of the ten most common Fucus vesiculosus, being the only large and diversified benthic macrophytes in Inre Verkviken in 1990- 1991, ex­ alga in most of the Baltic proper, has been of great interest tending as thin, erect siphonal threads into the water col­ for phycologists working in this area. Luther (195 1b) and umn. All over the inlet this species formed the deep-water Wcern (1952) described and discussed the distribution of limit of the vegetation, occurring alive as deep as 6.5 m.

F. vesiculosus in the Finnish and Swedish archipelago. The Christensen (1987) described V. dichotoma as plants usu­ decline of Fucus vegetation in Finland in the late 1970s and ally forming bearskin-like masses in calm water. Most early 1980s has been described in several papers (e.g. clones are only little or not at all fertile outside the salinity Kangas et al. 1982, Ronnberg et al. 1985). Kangas et al. range of 5-15 %o. From the British Isles "few brackish water ( 1982) also gave a model of the decline of F. vesiculosus off finds are recorded" (Christensen 1987). Rieth (1980) re­ the south coast of Finland. The ecology of the Fucus belt ported differences in sizes of filaments and reproductive from the archipelago of Aland was discussed by among structures in populations from deep oligotrophic lakes and others Ronnberg (1981, 1991), Ronnberg et al. ( 1985, 1991, from the Baltic Sea. Because of the common occurrence in 1992) and Lindholm et al. (1987, 1989). the northern part of the Baltic proper and in parts of the Gulf of Bothnia V. dichotoma has two names in the Swedish language. In Sweden people call it 'svartskinna' ('black kin' in Engli h) while on the Swedish peaking island of Discussion Aland it is called 'sjalgras' ('shawl grass' in English). From the Swedish Baltic coast Wcern(19 50, 1952, 1965, Three most interesting algal species, Cladophora aega­ Skytte Christiansen et al. 1976) reported the deep water gropila, Va ucheria dichotoma and Monostroma balticum V. dichotoma, which was pointed out as one of the "inter­ are here discussed in more detail. vening lacustrine species" in the Oregrund archipelago. Although Wrern (1952) mainly treated rocky-shore algae, Cladophora aegagropila he often mentioned V. dichotoma as a common member of the loose-lying vegetation. Later he described V. dichotoma The occurrence of this species in the Baltic Sea, being one of as a lacu trine and brackish water species, forming "vascu­ the most important algae in the whole Gulf of Bothnia, was lar meadows with semi-lacustrine impressions" and discussed by Wcern ( 1952, pp. 82-84) and he mentioned only V. dichotoma was mentioned occurring down to 7 m (Wrer n a few scattered records from the Baltic proper. In the 1965). We observed V. dichotoma for the first time in Tvarminne-Poj o area, S Finland, Luther (1951a) found a Finland, in the Tvarminne-Poj o area, together with our deep-water limit of 6.4 m for C. aegagropila. Later it has tutors Mats Wcern and Hans Luther at the First Nordic been recorded attached in several areas of the Gulf of Waterplant Cour e in 1953. On the Baltic Marine Biolo­ Bothnia and the Archipelago Sea (e.g. Ravanko 1 968, Hallfors gists' post-excursion to Huso Biological Station, Aland, in 1976, Kautsky et al. 1981, 1988, Lindholm & Ronnberg 1985 V. dichotoma was recorded as fertile in the Huso inlet. 1985, Lindholm et al. 1989), while it was not found in inner From the Aland archipelago V. dichotoma has been re­ parts of the Trosa-Asko area, the northern Baltic proper, corded as common in soft bottom associations of the 'flada's although searched for (Wa1lentinus 1979, p. 191). Interest­ (cf. Lindholm & Ronnberg 1985, figs 8 & 11, Lindholm et ingly, Kuylenstierna (1989-1 990) recorded this freshwater al. 1989, fig. 6). Mun terhjelm (1985, 1987) investigated a species as common in the innermost part of the Nordre Alv similar type of bottom in Nyland on the southern coast of estuary on the Swedish west coast. Finland and on Aland, and he particularly studied the suc­ Hall fors et al. (1987) discussed methodical aspects of the cession on soft bottom localities. V. dichotoma was also

Acta Phytogeogr. Suec. 78 106 H. Mathiesen & L. Mathiesen

Wrern (1952) recorded M. balticum in the Baltic Sea. Wrern ( 1950, 1952, 1965) mentioned M. balticum as endemic to the Baltic. In a survey of the one-layered Ulvaceae, Wrern (see Skytte Christiansen et al. 1976, pp. 283-284) gave short definitions which clearly separate the two species M. balticum and M. grevillei. He emphasized the thick walls of the former species, having margins often bent inwards, and a pale green colour and not adhering to the paper when pressed, while for the latter species the ability to stick to the paper and remaining clear green when pressed was pointed out, together with its occunence in early spring. The same features had also been noticed by Wittrock (1866). From the Archipelago Sea in Finland one of the present authors (L. M.) has collected loose-lying M. balticum at a depth of2-3 m from Kokar in the sound between Hellso and Finno, Aland, (June 17, 1955, det. M. Wrern). Wallentinus (1976, p. 98) has, in connection with Monostroma grevillei, described an alga found in spring 1975 " ... to a depth of about five metres. The dark colour and the entire, slightly wrinkled margins showed they were Fig. 2. (A) Cross section and (B) surface view of Monostroma not drifted algae, but were developed there." (cf. also balticum, drawn after material from Inre Verkviken, July 1991. Wallentinus 1979, pp. 16-17). These specimens according to our opinion might conespond to M. balticum. However, the plants were fo und in early April and in contrast to the recorded inshal low bays inthe Trosa-Asko area (Wallentinus characteristics given by Wrern(s ee above), those thin speci­ 1979, p. 194). mens adhered well to the paper when pressed (I. Wallentinus, pers. comm.). She also reported 'normal' M. grevillei as Monostroma balticum very common in the outer archipelago at Asko during spring (Wallentinus 1976, 1979), a species which she has observed Monostroma balticum was first described by Wittrock ( l 866) in the area since the start of her work in the mid 1960s as synonym of Ulva baltica Areschoug (according to unpub­ (I. Wallentinus pers. comm.). lished academic lectures by Areschoug in 1865). Sjostedt Ravanko (1968) recorded M. balticum from the archi­ (1920) recorded the species at Sirnrishamn (22 %o S) and pelago of Turku. However, later she (Ravanko 1969) con­ Lund ( 1 934) reported it as new for Denmark, at Stege Nor (8 sidered M. balticum as a modification of M. grevillei, a %o S). The figures in these publications (Sjostedt 1920, p. 14, species which in fact invaded the archipelago of SW Fin­ Lund 1934, pp. 24-25) are in accordance with the material land in the 1960s (cf. Hallfor et al. 1984). Ravanko in from Inre Verkviken, where M. balticum in cross section spring 1968 (January-May), was probably one of the first to (Fig. 2A) had 2-5.5 �m thick cell walls, 12-14 �m high cell register attached M. grevillei from this area. lumina, and a thickness of the thallus of 20-25 �m. Cell Ronnberg (198 1) recorded attached M. grevillei from the divisions in the thallus can be seen as nanow cells in Fig. 2A, Aland archipelago in January. One of the present authors and in surface view the thallus also has dividing cells (L. M.) found M. grevillei at Gullkrona fj ard, Hitis: Tunhamn between the adult cells, (cells measuring 11 x 7-9 �m, 13 x in the Archipelago Sea in May 1982. Hallfors et al. (1984) 9 �m, 11 x 5 �m, 6 x 9- 12 �m, 9 x 5-4 �m; Plate 1). Living reported that M. grevillei became a common alga in the material of M. balticum collected from Inre Verkviken in Tvarminne area in early spring in the mid 1970s, and July 1990 is depicted in Plate 2. increased in abundance and size in the late 1970s, favoured Christensen et al. (1985) listed M. balticum (Aresch. ex by increased salinities. Wittr.) Wittr. from the waters between Sjrelland and Lolland and around the island of Bornholm. Specimens collected from Inre Verkviken are referred to this species. However, Christensen & Thomsen ( 1974) only mentioned the species Conclusions Monostroma balticum (Aresch.) Wittr. as (Enteromorpha intestinalis modif.?), and Eliding (1963, 1968) in his revi­ The floristic examinations carried out during 1990-9 1 have sion of Ulvales did not include M. balticum, but gave a confirmed the interpretation of Inre Verkviken as a non­ thorough description of M. grevillei (Thur.) Wittr. (Eliding polluted coastal water area with rather clear water, i.e. not ­ 1968). or only slightly - affected by man. The submerged vegetation Svedelius (1901), Sjostedt (1920), Levring (1940) and is well-developed, and over large areas of the inlet it extends

Acta Phytogeogr. Suec. 78 Floristic aspects of In re Verkviken 107

Plate 1. Surface view of Monostroma balticum, material from Inre Verkviken, July 1991.

Plate 2. Samples of live Monostroma balticum from Inre Verkviken, July 1990.

Acta Phytogeogr. Suec. 78 I 08 H. Mathiesen & L. Mathiesen

toa depth of4-5 m, witha maximumdepth of6-6.5 m. Where Drepanocladus, contributed to the considerable amount of the bottom gently slopes downwards, the vegetation was organic matter found in many sampling sites of Inre very dense. Conspicuous were the dense characean commu­ Verkviken. nities with a biomass of l00-500 g dry matter m-2. Several katharobic as ociations (see Hallfor et al. 1987) In Inre Verkviken the number of macroalgal and were common in Inre Verkviken with Potamogeton chormophyte specie was fairly low, and only a few differ­ peroliatus,f P. pectinatus or Myriophy/lum sibiricum a the ent types of macrobenthic vegetation (association , en u dominating pecies. It has been pos ible to identify turions Hallfors et al. 1987) occuned. The species composition of of all the Myriophyllum plant we collected in Inre Verkviken, the individual plant communities observed within our sam­ and in all ea e the turions were curved. Our specimens of pling sites showed rather small variations from one cro Myriophyllum were very imi1ar to those collected by Mats ection to another. These features may be caused by the Wrern in the archipelago of Oregrund (Herbarium Wrern, table low salinity in combination with the fact that Inre Uppsala, collected 1982). Verkviken is a semi-enclo ed inlet. The mo t unexpected re ult of our floristic examinations However, the a sociations of the innermo t part (area I) is the lack of some chormophytes in Inre Verkviken, which clearly differed from the vegetation ob erved in the outer, normally grow in most coastal waters of the Baltic Sea with deeper parts of the inlet (areas 3-5). Furthermore, the ve­ similar salinities. Six specie , all included in the list of getation of area 6 gave evidence of an obvious influence of important species of katharobic associations (Hallfors et al. the fluctuating events of incoming water from theGulf of 1987), were not found in any of the over 300 sampling sites: Bothnia. In area 1 the shallow-water characean commu­ Batrachium circinatum (Sibth.) Spach, Littorella uniflora nitie belonged to associations which are known as 'flada'­ (L.) Asch., Myriophyllum spicatum L., M. verticillatum L., types. Most of the samples from shallow water were domi­ Zannichellia major Boenn. and Ceratophyllum demersum nated by Chara tomentosa, C. aspera and Najas marina. In L. Also Potamogeton berchtoldii and P. pusillus (syn. P. areas 4-6 most of the shallow-water characean communities panormitanus) were almost ab ent; only a few small plants belonged to the association described by Hayren as "Chara­ were observed. The impoverishment of the species diversity cetum arenicolum" (see Hallfors et al. 1987). In areas 5-6 may be eau ed by the locally table and low salinity; for Tolypella nidifica contributed substantially to the vigorous instance the lack of Zostera marina L. and Ruppia cirrhosa vegetation at 2-3 m depth and according to Luther (195 1 b) (Petagna) Grande may be related to the low salinity. But the this species avoids stagnant water. absence of the six specie mentioned above cannot only be Only a few species showed distribution pattern which due to alinity condition . were obviously clo ely related to an increa ing influence A in mo t of the other coa tal waters of Aland, both from inflowing water from the Gulf of Bothnia. Chara Chara tomentosa and Potamogeton filiormisf occur in the globularis wa ob erved in tand only in area 1-2, while flora of Inre Verkviken. Thi floristic characteri tic al o Ruppia maritima together with Batrachium baudotii were applie to a large number of water from Pojoviken (Luther found as rooted plants only in area 6. Also the scattered sites 1951a, 1951b), to the archipelago ofbregrund (Wrem 1 952), of Chorda filum and Ceramium tenuicorne were exclu- and to ome extent al o to the Trosa-A ko area (Wallentinus ively fo und in the northern, outer area , obviou ly as a 1976, 1 979). This is in contrast to the western Baltic, the result of water exchange with the Gulf of Bothnia. Danish Belt areas and the coa tal waters of the Kattegat. A characteristic fe ature of many (semi-)enclosed water There, in the outermo t parts of the Baltic area in a wide bodies is the development of large numbers of individual sense, both these species are absent in brackish bays. of one or very few species. Therefore it is not surprising that the observations ( 1990-9 1) included mass-occunence of ome algae forming loose-lying mats. In areas 4-5 both Vaucheria dichotoma and Drepanocladusfluitans occuned References over large areas, growing a dense mats at depths of 2-3 m. In 1990 the bioma s of uch Drepanocladus mats was 180- 2 Eliding, C. 1 963. A critical survey of European taxa in Ulvales. Part 600 g dry matter m- . Cladophora glomerata al o occuned I. Capsosiphon, Percursaria, Blidingia, Enterommpha. - in dense formations, and during the study period in both Opera Bot. 8 (3): 1-160. years the epiphytic growth of Cladophora glomerata was a Eliding, C. 1 968. A critical survey of European taxa in Ulva1e . Part dominating feature of many sampling sites at different II. VIva, Ulvaria,Monostroma, Kommannia. -Bot. Not. 121: depths. The loose-lying masses of Fucus vesiculosus - the 535-629. "crisp and proliferous Fucus" (Wrern 1952) - and also the Blindow, I. & Krause, W. 1990. Bestamningsnyckel fOr venska formations of Monostroma balticum, built up of dense kran alger. [Key to Swedish species of Charophyta.]- Sven. Bot. Tidskr. 84: 119-160. (With English ab tract.) carpets of healthy, very green individual , are further exam­ Cedercreutz, C. 1934. Die Algenflora und Algenvegetation auf ples of mass-occunences, which are not related to introduc­ Aland. - Acta Bot. Fenn. 15: 1-120. tion of nutrients or any other kind of pollution. On the other Cedercreutz, C. 1947. Die Gefasspflanzenvegetation der Seen auf hand uch formations, especially those of Va ucheria and Aland. - Acta Bot. Fenn. 38: 1-77.

Acta Phytogeogr. Suec. 78 Floristic aspects of Inre Verkviken 109

Chri stensen, T. 1 987. Sea weeds of the British I les.4. Tri boph yceae Lund, S. 1934. Die Algenvegetation in Stege Nor. - Bot. Tid skr. (Xanthophyceae). - British Museum (Natural Hi tory), Lon­ 43: 17-39. don. 36 pp. Luther, H. 1947. Morphologische und systematische Beobachtungen Christen en, T. & Thomsen, H.A. 1974. Algefortegnelse. Oversigt an Wasserphanerogamen.- Acta Bot. Fenn. 40: 1-28. over udbredel en af danske salt- og brakvandsarter fraset ikke­ Luther, H. 1951a. Verbreitung und Okologie der hoheren Wasser­ planktiske kiselalger. Forel0pig udgave. - Universitets­ pflanzen im Brackwasser der Ekenl:is-Gegendin SUdfinnland. bogladen, K0benhavn. 35 pp. I. Allgemeiner Teil. - Acta Bot. Fenn. 49: 1-231. Chri tensen, T., Koch, C. & Thomsen, H.A. 1985. Distribution of Luther, H. 1951b. Yerbreitung und Okologie der hoheren Wasser­ algae in Danish salt and brackish waters.- Univ. Copenha­ pflanzen im Brackwasser der Ekenl:i -Gegend in SUdfinnland. gen. 64 pp. ll. Spezieller Teil. -Acta Bot. Fenn. 50: 1-370. Hl:illfor , G. 1976. The plant cover of some littoral biotopes at Mathie en, H. 1 980. 60 ars vegetationsdynamik i Randers Fj ord. ­ Krunnit (NE Bothnian Bay). - Acta Univ. Oul. A 42: 87-95. In: M0ller, H.S. & Ovesen, C.H. (eds.) Status over den danske Hl:illfor , G., Kangas, P. & Niemi, A. 1984. Recent changes in the plante- og dyreverden. Fredning tyre! en, K0benhavn. pp. phytal at the south coast of Finland. - Ophelia, Suppl. 3: 51- 255-266. 59. Mathie en, H. & Mathiesen, L. 1976. Fa t vok ende vegetation i Hl:illfors, G., Yiitasalo, I. & Niemi, A. 1987. Macrophyte vegeta­ Rander Fj ord og Grund Fj ord. - In: Gudenaunder 0gelsen, tion and trophic statu of the Gulf of Finland - A review of Rapport ved Gudenaudvalget og Enviroplan. Aarhus Amts­ Finnish inve tigations. - Meri 13: 111-158. kommune, Aarhu . pp. 66-76. Hl:imet-Ahti, L., Suominen, J., Ulvinen, T., Uotila, T. & Vuokko, Mathiesen, H. & Nielsen, J. 1956. Botaniske under 0gelser i S. (eds.) 1989. Retkeilykasvio. - Suomen Luonnonsuolejun Randers Fj ord og Grund Fj ord. - Bot. Tidsskr. 53: 1-34. Tuki, Helsinki. 598 pp. Moeslund, B., L0jtnant, B., Mathiesen, H., Mathiesen, L., Pedersen, Hansen, K. (ed.) 1988. Dansk Feltflora. - Gyldendal, Copenha­ A., Thyssen, H. & Schou, J.C. 1990. Danske vandplanter. gen.757 pp. Vejledning i bestemmelse af planter i s0er og vand10b. - Hasslow, O.J. 1931. Sveriges characeer. -Bot. Not. 1931: 63- Milj0nyt, 2 1990. Milj0styrelsen, K0benhavn. 192 pp. 136. Munsterhjelm, R. 1985. Flador och glon. - Norden kiold­ Hl:iyren, E. 1944. Studier over saprob strandvegetation och flora i samfundets Tidskr. 45: 22-49. nagra ku tstlider i sodra Finland. - Bidr. Kanned. Finlands Mun terhjelm, R. 1987. Skl:irgardensflador och glon. - Skargard Nat. Folk 88 (5): 1-120. (With German summary.) 1987 (1): 10-17. Hayren, E. 1949. Studier over vattnets vegetation och flora i Stor­ Olsen, S. 1944. Danish Charophyta. - K. Danske Yid. Selsk. Bioi. Pernaviken. - Bidr. Kanned. Finlands Nat. Folk 93 (5): 1-62. Skr. 3: 1-240. (With German summary.) Ravanko, 0. 1968. Macro copic green, brown, and red algae in the Kangas, P., Autio, H., Hl:illfors, G., Luther, H., Niemi, A. & southwestern archipelago of Finland. - Acta Bot. Fenn. 79: Salemaa, H. 1982. A general model of the decline of Fucus 1-50. vesiculosus at Tvarminne, outh coa t of Finland in 1977-8 1. Ravanko, 0. 1969. Observations on the genus Monostroma in the -Acta Bot. Fenn. 118: 1-27. northern Baltic Sea area (Seili Island , SW archipeiago of Kautsky, H., Kautsky, U. & Nellbring, S. 1988. Distribution of Finland). - Bot. Not. 122: 228-252. flora and fauna in an area receiving pulp mill effluents in the Rieth, A. 1980. Xanthophyceae. 2 Teil. - In: Ettl, H., Gerloff, J. Baltic Sea. - Ophelia 28: 139- 155. & Heynig, H. (eds.) SUsswasserflora von Mitteleuropa. Band Kautsky, H., Widbom B. & Wulff, F. 1981. Vegetation, macrofauna 4. 147 pp. and benthic meiofauna in the phytal zone of the archipelago of Ronnberg, 0. 1981. Traffic effects on rocky-shore algae in the Lutea - Bothnian Bay. - Ophelia 20: 53-77. Archipelago Sea, SW Finland. - Acta Acad. Aboen is, Ser. B Kuylenstierna, M. 1989-90. Benthic algal vegetation in the Nordre 41 (3): l-186. Alv Estuary. (Swedi h West Coast.) Parts I-ll.- Thesis, Dept. Ronnberg, 0. 1991. Forandringar i bottenvegetation i Alandska

Marine Botany, Univ. Goteborg. 1-244 pp. + 76 plates with kargardsvatten.- M em. Soc. Fauna Flora Fenn. 67: l 02- 1 06. text. Ronnberg, 0., Adj ers, K., Ruokolahti, C. & Bondestam, M. 1992. Levring, T. 1940. Studien Uber die Algenvegetation von Blekinge, Effects of fish farming on growth, epiphytes and nutrient SUdschweden. - Diss., Univ. Lund. 178 pp. content of Fucus vesiculosus L. in the Atand archipelago, Lindholm, T. 1982. Dynamics of hydrography and primary pro­ northern Baltic Sea. - Aquat. Bot. 42: 109- 1 20. duction in three stratified coasta1 1akes on A1and (SW Finland). Ronnberg, 0. & Lax, P.-E. 1980. Influence of wave action on -Acta Acad. Aboensis, Ser. B. 42: l-75. morphology and epiphytic diatoms of Cladophora glomerata Lindholm, T. 1991. Fran havsvik till insjo. - Mi1j0forlaget, Abo. (L.) KUtz. - Ophelia, SuppJ. 1: 209-2 18. 160 pp. Ronnberg, 0., Lehto, J. & Haahtela, I. 1985. Recent changes in the Lindholm, T. & Ronnberg, 0. (eds.) 1985. Archipelago waters of occurrence of Fucus vesiculosus in the Archipelago Sea, SW NW Aland. Excursion guide. - Huso Bioi. Station, Abo Finland. - Ann. Bot. Fenn. 22: 231 -244. Akademi, Abo. 27 pp. Ronnberg, 0., bstman, T. & Adjer , K. 1991.Fucus vesiculosus as Lindholm, T., Bjorkqvist, D. & Mark, A.-C. 1987. Inre Verkviken an indicator of wash effects of ships' traffic. - Oebalia 17, 1 en meromiktisk havsvik pa norra Aland. - Norden kiold­ Suppl. 1991: 213-222. samfundet Tidskr. 47: 57-67. Sjostedt, L. G. 1920. Algologiska studier vid Skanes sodra och Lindholm, T., Ronnberg, 0. & bstman, T. 1989. Husoviken - en ostra kust. - Lunds Univ. Ar skr. N.F., avd. 2, 16(7): 1-40. flada i Aland kargard. [The Huso Bay - a flada in the Aland Skytte Christiansen, M., von Krusenstjerna,E. & Wrern, M. 1976. archipelago].-Sven. Bot. Tidskr. 83: 143- 147. (With English Var flora i flirg. Kryptogamer. - Almquist & Wiksell Forlag, ab tract and legend .) Stockholm. 325 pp.

Acta Phytogeogr. Suec. 78 110 H. Mathiesen & L. Mathiesen

Snoeijs, P.J .M. 1 989. Ecological effects of cooling water discharge Wrern, M. 1965. A vista on the marine vegetation. - Acta on hydrolittoral epihthic diatom communities in the northern Phytogeogr. Suec. 50: 13-27. Baltic Sea. - Diatom Res. 4 : 373-398. Wallentinus, I. 1976. Environmental influences on benthic Svedelius, N. 1901. Studier ofver Ostersjons hafsalgflora. - macrovegetation in the Trosa-Asko area, northern Baltic proper. Diss. Univ. Uppsala 140 pp. I. Hydrographical and chemical parameters, and macrophytic Wrern, M. 1945. Remarks on some Swedish Sphacelariaceae. ­ communities. -Contr. Asko Lab. Univ. Stockholm 15: 1-138. Sven. Bot. Tidskr. 39: 396-4 18. Wallentinus, I. 1979. Environmental influences on benthic Wrern, M. 1949. Remarks on Swedish Lithoderma. - Sven. Bot. macrovegetation in the Trosa-Asko area, northern Baltic proper. Tidskr. 43: 633-670. II. The ecology of macroalgae and submersed phanerogams.­ Wrern, M. 1950. Algological excursions to the middle part of the Contr. Asko Lab. Univ. Stockholm 25: 1-210. Swedish east coast. - Seventh Intern. Bot. Congr. Stockholm Wittrock, V.B. 1866. Forsok till en monographi Ofver algsHi.ktet 1950. Excursion Guides B3 and Cilia, Uppsala. 38 pp. Monostroma. - Academisk Afhandling. Univ. Uppsala. 66 Wrern,M. 1952. Rocky-shore algae in the bregrund Archipelago. pp. + 4 Plates. - Acta Phytogeogr. Suec. 30: 1-298.

Acta Phytogeogr. Suec. 78 Marine algae south of the island Vej rp, the Samsp area, Denmark

Ruth Nielsen 1 & Karsten Dahf2

Abstract Nielsen, R. & Dahl, K. 1992. Marine algae outh of the island Vejr(ll, the Sams(ll area, Denmark

- Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-72 10-078-8.

The marine benthic algal vegetation south of the island Vejr(ll, Denmark, was studied in 1989, 1990, and 1991. The species composition was related to substrate (sizes of stones), depth, and season. Comparisons were made with the results obtained by Rosenvinge in 1892 and 1925. He recorded 38 taxa while 111 species were identified in this study.

Keywords: Depth distribution; Drifting algae; Kattegat;Macrophytobenthos; Monitoring; Substrate.

'Botanical Museum, Gothersgade 130, DK-1123 Copenhagen K, Denmark. 2Th e National Forest and Nature Agency, Slotsmarken 13, DK-2970 Ht;Orsholm, Denmark.

Introduction water level since the ice age have resulted in a geomorphology where small islands are surrounded by submerged beach Knowledge of the vegetation on stone reefs in the Danish plains cut through by deep channels. The study area is part of Kattegat dates back to L.K. Rosenvinge, who built up located at the southern end of Vejr0 with the 41 collections many collections at the end of the last and the beginning of obtained from 0.5-19 m on a transect of such a beach plain this century. His collections were obtained by dredging from and down the slope of one of the channels. From a depth of boats, and are kept in the Botanical Museum of Copenhagen 6 m a steep slope falls down to 22-25 m. Registration (C) together with his notebooks. The specimens and notes, numbers for the collecting sites are given in Table 1,together together with the publication 'The marine algae of Denmark' with depths, dates, and coordinates. (Rosenvinge 1909- 1931, Rosenvinge & Lund 1941, 1943, Divers estimated the cover of sand, gravel, and stones of 1947, Lund 1950), allow comparisons between species different sizes expressed as a percentage of the entire bot­ composition today and about 75-100 years ago. tom area. In accordance with national guidelines (Jespersen The observations from the island of Vejnzj reported here et al. 1988), the percentage cover of the vegetation in form part of an ongoing monitoring program in Danish general and of individual species on each kind of substrate waters. The aim is to obtain background data, in order to was also estimated. Only attached algae were estimated, but fo llow possible future changes in algal composition and large amounts of drifting algae were also found. Videotapes depth distribution, which might reflect the planned reduc­ of the study sites are kept at the National Forest and Nature tion of nitrogen and phosphorus discharge (Anon. 1987). Agency. The different counties report on the vegetation of coastal The material was identified in the laboratory; herbarium waters while the National Forest and Nature Agency is mounts are kept at C. The nomenclature generally fo llows responsible for stone reefs in open areas (Nielsen 1991, Christensen et al. (1985). Collection periods were so short Nielsen & Dahl in press). and the material so diverse that it was only possible to deal with a small portion of the algae while still fresh. Therefore, formaldehyde was added to most samples immediately after collection (final concentration 0.5- 1 % ). Samples which could Material and Methods not be processed within a few weeks were kept in a deep­ freezer. Vejr0 is situated in the southwestern part of the Kattegat (Fig. 1 ), within the Sams0 area (Sa), according to Rosenvinge (1909-1931). The salinity in this area is approximately 18.5 Results %o at the surface. Geologically, the area is characterized by glacier deposits from the last ice age. Large variations in At the study sites, the bottom consists of a mixture of sand,

Acta Phytogeogr. Suec. 78 112 R. Nielsen & K. Dah/

gravel, and small stones le s than 5 cm in diameter cover the larger part of the bottom at many site . Scattered stone I 0- 30 cm or 50-60(-100) cm in diameter also occurred. In 57° SWEDEN addition to the stones, shell of Modiolus modiolus (L.) fu nction as substrate for attached organisms at a depth of 16- 18 m. The complete specie li t is given in Table 2. Compari­ sons with the check-list by Chri tensen et al. ( 1985) reveals a number of species not reported from the area (Sa). These are indicated by an asterisk except for Chromastrum humile, reported by Andersen ( 1983), and Antithamnion cruciatum, reported by Nielsen et al. (1990). Of the 111 species found 25 pecie are new to the area (Sa), of which Plectonema golenkinianum is new to Denmark. Table 2 also show the depth di tribution with observations indicated at 1 and 2 m interval . Over 50 species were recorded at each interval Fig. 1. Location map, howing the position of the island of YejrS/.1. from 4- 15 m (Table 3). At 16-18 m, the number of species decrea ed to approximately 50%, and only 25% occurred at gravel and stones and there is no correlation between stone 18-19 m depth. Vegetation cover below 15 m was sparse size and depth. At the same depth, some sites have relatively with few upright, generally small algae. Phycodrys rubens many large stone while others have only a few. Sand, wa dominant, and especially well-developed on the large shells of Modiolus modiolus. Stone size has a great influence on the composition of the Table 1. The collecting ite . vegetation. Pebbles 2-3 cm in diameter generally were covered by crustose algae and erect vegetation only oc­ Registration Depths Dates Coordinate number curred on larger stones. Chorda fi lum was found on stones measuring 1.5-5 cm, and Ectocarpus siliculosus which, in RN89026 0.5 09.04. 1989 55°56' N W046' E RN890 18 1.5 09.04. 1989 55°56' N 10°46' E addition to it occurrence a an epiphyte, was recorded on RN90054 5.0 13.06. 1 990 55°56.45' W046.0 1' E stone of different sizes, the smallest with a diameter of 1.5 R 90078 5.0 10.08. 1 990 55°56.45' N 10°46.03' E 2-8 RN91028 5.0 05.06. 1991 55°56.443' N I 0°45.957' E cm. Stone cm across were often covered by hort-lived R 89015 5.0 08.04. 1989 55°56.42' 10°45.99' E algae such as Polysiphonia urceolata, Chorda fi lum, RN890 19 5.0 02.06. 1989 55°56.45' 10°46.00' E Halosiphon tomentosus, and Bryopsis hypnoides, or mall RN900 17 5.5 06.04. 1990 55°56.46' N 10°46.05' E RN900 16 6.5 06.04. 1990 55°56.44' N 10°46.04' E plants of Ahnfeltiaplicata, Polysiphonia elongata, P. nigre­ RN9005 1 7.0 13.06. 1 990 55°56.40' N 10°45.99' E scens, and Rhodomela confervoides, frequently only a sin­ R 90077 7.0 10.08. 1990 55°56.4 1' N 10°45.98' E R 91024 7.0 05.06. 1991 55°56.36' 10°45.99' E gle pecie on each stone. Larger tones and boulders had a R 89024 7.0 02.06. 1989 55°56.39' 10°46.03' E den e cover of mixed algae. RN89017 8.0 09.04. 1989 55°56.45' 10°46.05' E RN90015 9.0 06.04. 1990 55°56.42' 10°46.04' E There were many epiphytes, mainly fi lamentous red al­ R 90050 9.0 13.06. 1 990 55°56.40' 10°45.99' E gae, on Furcellaria lumbricalis, Phyllophora pseudo­ R 90076 9.0 10.08. 1990 55°56.4 1' 10°46.04' E ceranoides, and P. truncata. P. truncata was the most RN91 023 9.0 05.06. 1991 55°56.364' 10°45.999' E R 89025 9.0 02.06. 1989 55°56.40' I 0°46.03' E frequent among the host plants, at many sites covering more RN900 13 11.0 06.04. 1990 55°56.4 1' N 10°46.06' E than 25% of the available sub trate. In addition, large plants RN90049 11.0 13.06. 1 990 55°56.40' N 10°46.06' E RN90075 11.0 10.08. 1 990 55°56.4 1' 10°46.04' E of Delesseria sanguinea, Phycodrys rubens, Laminaria R 91027 11.0 05.06. 1991 55°56.334' N 10°45.989' E digitata, and L. saccharina grew also on stones of thi size. RN89020 11.0 02.06. 1989 55°56.38' N 10°46.05' E RN900 14 13.0 06.04. 1990 55°56.34' N 10°45.94' E Crustose brown, red, and coralline algae occurred on tones R 90048 13.0 13.06. 1 990 55°56.40' 10°46.06' E of all ize categories, but the corallines were not observed in R 90074 13.0 10.08. 1 990 55°56.37' 10°45.98' E large quantities at any depth. RN91026 13.0 05.06. 1991 55°56.334' N W045.989' E R 890 16 13.0 09.04. 1989 55°56.40' 10°46.09' E Some species are ea onal at Vejnzl.Haplospora globosa R 89023 13.0 02.06. 1989 55°56.38' 10°46.04' E and Monostroma grevillei were only recorded in April. The RN900 12 15.0 06.04. 1990 55°56.38' N 10°46.05' E RN90052 15.0 13.06. 1 990 55°56.36' 10°46.03' E occurrence of the rare brown alga Polytretus reinboldii in RN90073 15.0 10.08. 1 990 55°56.35' 10°46.04' E April 1989 agrees with other Scandinavian records from the RN91025 15.0 05.06. 1991 55°56.336' 10°46.0 15' E 1977, 1941, RN89022 15.0 02.06. 1989 55°56.35' 10°46.05' E spring (Pedersen Rosenvinge & Lund Wrern RN8902 1 16.5 02.06. 1989 55°56.35' 10°46.05' E 1958). Specimens 1.5-3 cm long occurred on tones 2-5 cm RN90053 17.0 13.06. 1 990 55°56.35' 10°46.05' E in diameter, and sori of plurilocular porangia were pre ent. RN90072 17.0 10.08. 1 990 55°56.36' W046. 10' E RN91022 17.0 05.06. 1991 55°56.333' I 0°46.062' E Dumontia contorta, and Halosiphon tomentosus were re­ R 890 14 18.0 08.04. 1989 55°56.39' N 10°46.09' E corded in April and June: Eudesme virescens wa only R 91021 19.0 05.06. 1991 55°56.333' N I 0°46.062' E noticed in June. Brongniartella byssoides, Polysiphonia

Acta Phytogeogr. Suec. 78 Marine algae of the Sams� area 113

Table 2. Species list of the algae collected at Yejr�. An asterisk Taxa Depth 0.5 1.5 5 11 13 15 17 19 indicates a new record for the area. +: Collections 1892 and 1925. Pterothamnion plumula (El lis) Nag. 0 0 0 0 o : Collections in 1989- 1991. ffi : Collections 189211925 and 1989- Rhodochorton purpureum (Lightf.) Ro env. 0 0 Rhodomela confervoides 1991. Depths in m (average of interval). 1892, dredging at 4- 13 m, (Huds.) Silva 0 0 Ell 0 0 0 0 0 Scagelia pylaisaei indicated as 9 1925, hand dredging indicated as 0.5 (Mont.) Wynne 0 m; m. Spermothamnion repens (Dillw.) Rosenv. 0 0 Ell 0 0 0 0 Taxa Depth 0.5 1.5 5 11 13 15 17 19 Fucophyceae Brown cru t 0 0 0 0 Chorda filum Nostocophyceae (L.) Stackh. + 0 0 Ell 0 0 0 Chordaria jlagelliformis Calothrix confervicola (Roth) (O.F. Miill.) C. Ag. + 0 0 0 *Cutleria multi.fida (Sm.) C. Ag. ex Born & Flah. 0 Ell 0 0 Grev. (Aglaozonia-stage) Calorhrix sp. + 0 0 0 0 0 0 0 0 Desmarestia aculeata *Cyanocystis olivacea (Reinsch) (L.) Lamour. 0 Desmarestia viridis (O.F. Miill.) Lamour. Komarek & Anagnostidis 0 0 0 0 0 0 0 0 0 0 0 0 Dictyosiphon foeniculaceus *Dermocarpa schousboei (Thur.) Born 0 0 (Huds.) Grev. + 0 0 *Hyel/a balani Ectocarpus siliculosus Lehm. 0 0 0 (Dillw.) Lyngb. + 0 0 0 0 0 0 0 0 Elachistafucicola *Hyella caespitosa Born. & Flah. 0 0 0 (Yell.) Are eh. + + Eudesme virescens Hyella p. 0 Isactis sp. + (Cann. ex Harv. in Hook.) J. Ag. 0 0 0 0 0 *Lyngbya martensiana Fucus serratus Menegh. 0 0 0 0 0 0 0 L. + Ell Mastigocoleus testarum Lagerh. Fucus vesiculosus L. + 0 + Ha/idrys siliquosa ex Born. & Flah 0 (L.) Lyngb. + Halosiphon tomentosus *Piectonema battersii Gom. 0 (Lyngb.) Jaasund 0 0 0 0 0 0 0 * Plectonema golenkinianum Haplospora globosa Go m. 0 Kjellm. 0 0 * Plectonema terebrans Laminaria digitata Born. & Flah. ex Gom. 0 (Huds.) Lamour. 0 0 Ell 0 0 0 0 Rivularia sp. + Laminaria saccharina (L.) Lamour. 0 0 Ell 0 0 0 0 0 Laminaria Bangiophyceae sp. 0 *Acrochaetium daviesii Leptonematellafasciculata (Dillw.) Nag. 0 0 (Reinke) Silva 0 0 0 0 Acrochaetium strictum Litosiphon laminariae (Ro env.) Hamel 0 0 (Lyngb.) Harv. 0 0 0 0 Acrochaetiurn thuretii Myriotrichia clavaeformis (Born.) Coli. & Herv. 0 0 0 0 0 0 Harv. + Ahnfeltia plicata Petaloniafascia (Huds.) Fries 0 0 0 0 0 0 0 0 (O.F. Miill.) 0. Kuntze 0 *Petroderma maculiforme Antithamnion cruciatum (C. Ag.) Nag. 0 0 0 0 0 0 (Wollny) Kuck. 0 Audouinella efjlorescens Pilayel/a littoralis (J. Ag.) Papenf. Ell 0 0 (L.) Kj ellm. 0 0 Audouinella membranacea *Polytretus reinboldii (Magn.) Papenf. 0 0 0 0 (Reinke) Sauv. 0 *Audouinella pectinata Pseudolithoderma extensum (Kylin) Papenf. 0 0 0 Bangia atropurpurea (Roth) C. Ag. 0 (Crouan frat.) S. Lund 0 Bormemaisonia hamifera Pseudolithoderma Hariot (Trailliella-stage) 0 0 0 sp. 0 0 0 0 0 0 0 Brogniartella byssoiaes Punctaria tenuissima (Good. & Woodw.) Schm. 0 Ell 0 0 0 0 (J. Ag.) Grev. 0 Callithamnion corymbosum Ralfsia (Sm.) Lyngb. 0 0 0 0 0 0 sp. + Callithamnion hookeri Scytosiphon lomentaria (Dillw.) S.F. Gray 0 (Lyngb.) Link 0 0 0 Ceramium diaphanum Scytosiphon lomentaria (Lightf.) Roth 0 0 0 0 0 Ceramium rubrum (Hud .) C. Ag. + 0 0 Ell 0 0 0 0 (Lyngb.) Link (crusto e-stage) 0 Ceramium *Sphacelaria caespiltlla sp. 0 0 Lyngb. 0 0 0 Ceramium strictum Sphacelaria cirrosa Harv. 0 0 0 (Roth) C. Ag. 0 0 Ell 0 0 Chondrus crispus Sphacelaria plumosa Stackh. 0 0 Ell 0 Lyngb. 0 Ell 0 0 0 0 Sphace/aria rigidu/a Chromastrum hal/andicum (Kylin) Papenf. + Kiitz. 0 0 0 Chromastrwn hwnile Sphacelaria (Rosenv.) Papenf. 0 0 p. 0 0 0 Chromastrum virgatulum Sphaerotrichia divaricata (Harv.) Papenf. s.l. + 0 0 0 0 0 0 (C. Ag.) Kylin + 0 0 0 0 Stictyosiphon tortilis Conchocel is-stage 0 0 0 0 0 0 0 (Rupr.) Corallina offi cina/is L. + Reinke sensu Rosenv. 0 0 0 0 0 0 Cruoria pellita Striaria attenuata (Lyngb.) Frie 0 0 0 (Grev.) Grev. 0 Crustose red algae 0 0 0 Chlorophyceae *Acrochaete repens Cru to e red algae, calcified 0 0 0 0 0 0 0 0 Pringsh. 0 0 0 0 0 0 Cystoclonium purpureum Acrochaete viridis (Huds.) Batt. 0 0 Ell 0 0 0 (Reinke) R. Nielsen 0 Delesseria sanguinea *Blastophysa rhizopus (Huds.) Lamour. 0 0 Ell 0 0 0 0 0 Reinke 0 0 0 0 Dilsea carnosa Bolbocoleon piliferum (Schmidel) Kuntze 0 N. Pringsh. 0 0 0 0 0 Dumontia contorta Bryopsis hypnoides (Gmel.) Rupr. 0 0 0 0 0 0 0 Lamour. 0 0 0 0 Erythrotrichia carnea Chaetomorpha melagonium (Dillw.) J. Ag. 0 0 0 0 0 Furcellaria lumbricalis (Huds.) Lamour. 0 0 0 0 0 0 0 0 (Web. & Mohr.) Kiitz. 0 0 0 0 0 0 0 Haemescharia hennedyi *Cladophora pygmaea (Harv.) Wilce & Maggs 0 + 0 0 0 Reinke 0 0 0 0 0 0 0 Harveyella mirabilis Cladophora rupestris (Reinsch) Reinke 0 (L.) Kiitz. 0 0 0 0 0 0 0 *Hildenbrandia crouanii Cladophora sericea (Huds.) Kiitz. (1. Ag.) J. Ag. 0 0 0 0 0 0 0 0 Hildenbrandia rubra Cladophora (Sommerf.) Menegh. 0 0 Ell 0 0 0 sp. 0 0 0 0 0 0 0 Hildenbrandia *Derbesia marina sp. 0 0 0 0 0 (Lyngb.) Sol. 0 Meiodiscus spetsbergensis Enteromorpha linza (Kjellm.) (L.) J. Ag. 0 Enteromorpha prolifera Saunders & McLachlan 0 0 (O.F. Miill.) .J. Ag. 0 0 0 0 *Epicladia jlustrae Melobesia membranacea (Esper) Lamour. 0 Reinke 0 0 Membranoptera alata Epicladia phillipsii (Huds.) Stackh. 0 0 Ell 0 0 0 (Batt.) R. Nielsen 0 Palmaria palmata *Eugomontia sacculata (L.) 0. Kuntze 0 Ell 0 Kornm. 0 0 0 0 0 0 Phycodrys rubens *Gomontia polyrhiza (L.) Batt. 0 0 Ell 0 0 0 0 0 (Lagerh.) Born. & Flah. 0 Phy/lophora pseudoceranoiaes (Gmel.) Monostroma grevillei' (Thur.) Wittr. 0 0 0 *Ochlochaete hystrix Newroth & Taylor 0 0 0 0 0 0 0 Thwaites ex Harv. 0 0 0 Phyllophora *Ostreobium quekettii sp. 0 Born. & Flah. 0 0 0 0 0 0 Phyllophora truncata Spongomorpha centralis (Pallas) Zinova 0 0 0 0 0 0 0 0 (Lyngb.) Kiitz. 0 Polyiaes rotundus Ulothrix jlacca (Huds.) Grev. 0 0 0 0 0 0 0 (Dillw.) Thur. in Le Jol. 0 Polysiphonia elongata Ulothrix subjlaccida (Huds.) Spreng. 0 0 Ell 0 0 0 0 0 Wille 0 Polysiphonia nigrescens *Uronema curvata (Huds.) Grev. + 0 0 Ell 0 0 0 0 Printz 0 0 0 0 Polysiphonia urceolata Urospora penicilliformis (Lightf. ex Dillw.) Grev. 0 0 Ell 0 0 0 0 0 (Roth) Aresch. 0 Polysiphonia vio/acea (Roth) Spreng. 0 0 0 0 0 0

Acta Phytogeogr. Suec. 78 114 R. Nielsen & K. Dahl

Fig. 2. Delesseria sanguinea in Fig. 3. Delesseria sanguinea in June Fig. 4. Phycodrys rubens in April at April at 15 m. Scale = 5 cm. at 15 m. Scale = 5 cm. 15 m. Scale = 5 cm.

violacea, Pterothamnion plumula, Spermothamnion repens, Chorda filum, and Chordaria jlagellifo rmis, appeared in June and had developed into large plants by August. Ceramium strictum, Dictyosiphonfoeniculaceus, Sphaero­ trichia divaricata and the small epiphytes Calothrix confervicola, Acrochaetium strictum, Chromastrum humile, Melobesia membranacea, Litosiphon laminariae, and Acrochaete repens were not observed until August. Many species varied in size and appearance throughout the investigated period. Polysiphonia urceolata and Halosiphon tomentosus were very conspicuous in April. Bryopsishypnoides appeared in June, together with species ofEnte romorpha and Cladophora. At this time H. tomentosus wa decaying and nearly without the brown hair-like threads, while Chorda filum had developed into similarly looking

Fig. 5. Phycodrys rubens in June at 15

m. Scale = 5 cm.

Table 3. Number of species recorded at different depths, 1989-91 .

Depth Nostoco- Rhodo- Fuco- Chloro- Total (m) phyceae phyceae phyceae phyceae

0- 1 1 I 0 4 6 1-2 0 0 7 2 9 4-6 5 28 17 13 61 6-8 2 28 12 9 51 8- 10 5 33 18 13 70 10-12 5 31 19 10 62 12-14 5 36 15 12 67 14-16 3 35 14 11 63 16-18 2 18 7 6 33 18-20 13 2 2 18

Total 10 47 30 24 Ill

Acta Phytogeogr. Suec. 78 Marine algae of the Sams(J area 115

bunche of cords. Delesseria sanguinea and Phycodrys Vejrf{j. Halidrys siliquosa was observed in the drift material rubens had young blade in April, at depth of 13 m or less. at 17 m. The small Chromastrum hallandicum wa possibly Their development was delayed at greater depths; at 15 m overlooked, while the absence of Corallina of ficina/is from only D. sanguinea had sma!J young blade in April, while our pecie list probably is caused by a generally scattered P. rubens looked dark at that time and new blades were not occurrence (Nielsen et al. 1991 ). C. officinalis and H. sili­ seen until June (Figs. 2-5). On larger stones and boulders quosa have recently been reported from the area (Ra mus­ algae were present only a mall plants in April, of which sen 1989, Knudsen 1990). Myriotrichia clavaeformis usu­ Ceramium rubrum and everal species of Polysiphonia ally occur as an epiphyte in shallow-water localities in late became dominant in June and August. Brongniartella summer, a time when we did not collect algae at that depth. byssoides and Cystoclonium purpureum became conspicu­ So the absence from our list does not exclude the possible ou during the same period. Ectocarpus siliculosus gave the presence of these species at Vejrf{j. Therefore, the study vegetation a fuzzy appearance in June, and, as Cladophora showed no reduction in number of species at Vejrf{j during sericea, formed detached extensive mats at all depths in the la t century. August. During the pre ent study, Desmarestia viridis was The diffe rence in number of pecies identified by only recorded in June with very large specimen up to 80 cm Rosenvinge (34) and in the present investigation (111) doe long at 15 m in 1991. On other stone reefs in the Kattegat, it not necessarily indicate an invasion of species to the area. ha also been ob erved at other periods, usually with rela­ The collecting methods are different, and the sampling in tively large thalli in early summer (Nielsen 1991). 1989-9 1 was more extensive and undertaken at different Laminaria digitata and L. saccharina were very con­ seasons for three consecutive years at a number of depth spicuous, with blades lying on the bottom. The largest intervals. We also have dealt with groups of algae probably L. digitata was collected in June 1991 at 11 m. The blade neglected by Rosenvinge such as the small algae growing wa 260 cm long and about 50 cm broad, and the tipe was within calcified material and the small epiphytic green 12 cm long. The longest plant of L. saccharina was ob­ algae. served at 7 m depth, also in June 1991. The blade was 193 The presence of many drifting algae at variou depths, cm long and 25 cm broad, carrying an old blade which was which are easily caught by a dredge, indicates that a more 49 cm long; the stipe wa 12 cm long. New as well as old precise comparison with result obtained by dredging may blades were recorded on many plants of both species in be of limited value. Depth distribution of different species April and June. In some ea e , L. digitata had two genera­ of algae wa not recorded by Rosenvinge, but even if he tion of blades pre ent even in August (13 m, 1990). would have dredged along the depth contours, a comparison Many drifting algae were ob erved at 11-17 m in August of depth di tribution would hardly be possible, because of 1990, and at 9- 19 m in June 1991. These algae covered 50- the risk of getting drift algae in the dredge. However, it 90% of the bottom at the two deepest tations in 1991. might till be possible to detect major changes for a certain Ceramium rub rum, Ectocarpus siliculosus, and Cladophora area, such as any disappearance of fucoids and kelps or sericea were the dominant species, and Polysiphonia other prominent algae. nigrescens, Phyllophora truncata, Chorda filum, Halidrys siliquosa, Laminaria digitata, and L. saccharina also oc­ curred. Acknowledgements. Thank are due to P. Corfixen for valuable help in processing the data obtained, to Wm. J. Woelkerling for correcting the English text, and to the divers K. Lundshf{jj and S. Lundsteen for logistics. P.M. Discussion Pedersen kindly identifiedPolytretus reinboldii and L. Christiansen made the photographs. Unfortunately, extremely few records of marine algae obtained by diving exist from Danish waters before the early 1980s, whereas in Sweden diving data have been available since the 1930s (Wrem 1945, 1952, 1965). Rosenvinge collected algae at Vejrf{j in July 1892 by References dredging from a boat between 13 and 4 m and, in August 1925 from land by using a hand dredge. The taxa found by Anon. 1987. Beretning om vandmiljpplanen. Beretning afgivet af him are listed in Table 2, with records from 1 892 entered at miljp- og planlregningsudvalg den 30. april 1987. - Folke­ tinget 1986-87, blad nr. 817. Copenhagen. 9 m and those from 1925 at 0.5 m. Ander en, J. 1983. Benthi ke alger fra Ebeltoft Vig. - Silkeborg. Rosenvinge recorded 38 taxa from Vejrf{jin 1 892 or 1925. 50 pp. Of the identified species all but 5 were found in the present Christensen, T., Koch, C. & Thomsen, H.A. 1985. Di tribution of tudy. Of those five, Elachistafucicola occurred on a drift­ algae in Danish salt and brackish waters. - Institut for ing specimen of Fucus vesiculosus in April 1989; it is likely Sporeplanter, University of Copenhagen, Copenhagen. 64 pp. that it originated from the shallow-water vegetation off Jespersen, H., Kaas, H., Larsen, G.R., Nielsen, K., Laursen, J.S.,

Acta Phytogeogr. Suec. 78 116 R. Nielsen & K. Dahl

Rask, N. & Schwrerter, S. 1988. Bundvegetation. 28 pp. In: - Fyns Amt, Odense. 59 pp. Retningslinier for marin over vagning. - MiljlZ!styrelsens Rosenvinge, L.K. 1909-1931. The marine algae of Denmark. Havforureningslaboratorium. Contributions to their natural history. Vol. I. Rhodophyceae. Knudsen, L.J. 1990. VegetationsunderslZ!gelse omkring Fornres, - K. danske Videnssk Selsk. Skr., 7. Rrekke, Naturv. og 1989. - Arhus Arntskommune, HlZ!jbjerg. 55 pp. Matb. Afd. VII, 1-4: 1-630. Lund, S. 1950. The marine algae of Denmark. Contributions to Rosen vinge, L.K. & Lund, S. 1941. The marine algae of Denmark. their natural history. Vol. II, Phaeophyceae, IV. Sphace­ Contributions to their natural history. Vol. II. Phaeophyceae. lariaceae, Cutleriaceae, and Dictyotaceae - Bioi. Skr. 62(2): I. Ectocarpaceae and Acinetosporaceae. - Biol. Skr. 1 ( 4 ): 1- 1-80. 79. Nielsen, K., Hansen, D.F. & Boller, P. 1990. Bundvegetation, Rosenvinge, L.K. & Lund, S. 1943. The marine algae of Denmark. Arhus Bugtog KallZ!vig, Status 1 989.- Arhus Amtskornrnune, Contributions to their natural history. Vol. II. Phaeophyceae. HlZ!jbjerg. 69 pp. II. Corynophlaeaceae, Chordariaceae, Acrothricaceae, Nielsen, R. 1991. Vegetation of Tl2SnnebergBa nke, a stone reef in S permatochnaceae, S porochnaceae, Desrnarestiaceae, Arthro­ the northern Kattegat, Denmark. - Oebalia 17 (Suppl.): 199- cladiaceae with supplementary comments on Elachistaceae. 211. -Bioi. Skr. 2(6): 1-59. Nielsen, R. & Dahl, K. In press. Macroalgae at Briseis Flak, Rosenvinge, L.K. & Lund, S. 1 947. The marine algae of Denmark. Schultzs Grund, and Store Middelgrund, stone reefs in the Contributions to their natural history. Vol. II. Phaeophyceae. southernand easternpart ofKattegat, Denmark.-Proceedings Ill. Encoeliaceae, Myriotrichiaceae, Giraudiaceae, Striaria­ of the 12th Baltic Marine Biologists Symposium. Intern. ceae, Dictyosiphonaceae, Chordaceae, and Larninariaceae. Symp. Ser. -Bioi. Skr. 4(5): 1-99. Nielsen, R., Helrnig, S. & Hygum, B. 1991. Lysegrund, et stenrev Wrern,M. 1945. Remarks on some Swedish Sphacelariaceae. ­ i den sydlige del af Kattegat. Algevegetation, august 1990. ­ Sven. Bot. Tidskr. 39: 396-418. Wrern,M. 1952. Rocky-shore algae in the bregrund Archipelago. MiljlZ!rninisteriet. Skov- og Naturstyrelsen. HlZ!rshotm. 51 pp. -Acta Phytogeogr. Suec. 30: 1-298. Pedersen, P.M. 1977. Polytretus reinboldii, a rare brown alga in Wrern, M. 1958. Phycological investigations of the Swedish west culture (Ectocarpales, Sorocarpaceae fam. nov.).- Bot. Not. coast. I. Introduction and study of the Gaso shell-bottom. - 130: 35-40. Sven. Bot. Tidskr. 52: 319-342. Rasmussen, M.B. 1989. VegetationsunderslZ!gelserpa 6 eksponerede og 2 beskyttede lokaliteter i kystvandene omkring Fyn 1988. Wrem, M. 1965. A vista on the marine vegetation. - Acta Phytogeogr. Suec. 50: 13-28.

Acta Phytogeogr. Suec. 78 Changes in fucoid distributions and abundances in the inner Oslofjord, Norway : 1974-80 versus 1988-90

l 2 2 l l To r L. Bokn , , Steven N. Murray , Frithjof E. Moy & fan B. Magnusson

Abstract Bokn, T. L. et al. 1 992. Change in fucoid distribution and abundances in the innerO lofjord, Norway: 1974-80 versus 1988-90. -Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-7210- 078-8.

Abundances of five species offucoid were estimated at 123 station di tributed throughout the inner Oslofjord during 1988-90 and the results compared with similar surveys performed during 1974-80. Cluster analysis revealed that 79 of the 123 sites remained clas ified in the arnefour site groups when 1974-80 and 1988-90 dendrograrnswere compared. The two site groups containing the best developed fucoid vegetation showed significant increases in Fucus spiralis and decreases in F. evanescens from 1974-80 to 1988-90. A total of 30 sites was assigned to 1988-90 site clusters characterized by increased fucoid richness or abun­ dance, whereas 14 sites were classified within clusters exhibiting declines in their fucoid vegetation. Sites moving to improved clusters were characterized by significant increases in Fucus spiralis while maintaining high abundances of F. evanescens. Sites classified within clusters revealing decreases in their fucoid vegetations showed significant declines in four species (F.spiralis, F. vesiculosus, F. evanescens, and F. serratus). Results of the 1988-90 analyses indicate that improvements in the fucoid vegetation have occurred in many parts of the inner Oslofjord since 1974-80 and that these increases in fucoid richness and abundance appear to correspond with improvements in sewage treatment and discharge practices.

Keywords: Ascophyllum; Fucus; Nutrients; Pollution; Sewage.

!Norwegian Institute fo r Wa ter Research, P.O. Box 69, Korsvoll, N-0808 Oslo, Norway; 2Department of Biological Science, Caliorniaf State University, Fullerton, CA 92634, USA.

Introduction As indicated for example by Lewis ( 197 6) and J ones et al. (1979), long-term records of species distributions and abun­ Analyses of the distributions and abundances of benthic dances for assessing changes in marine littoral benthic organisms have frequently been used to assess natural or populations or communities are extremely rare. For the human-induced changes in shallow-water marine en­ inner Oslofjord (Fig. 1) however, survey data on littoral vironments (Smith et al. 1990). Perennial fucoids, which are sea weeds are available for various periods over the past 100 conspicuous components of sheltered or semi-sheltered lit­ years (Gran 1897, Simmons 1898, Sundene 1953, Grenager toral and upper-sublittoral benthic communities throughout 1957, Rueness 1973, Klavestad 1978, Bokn & Lein 1978, northwestern Europe, are particularly good indicator spe­ Bokn 1979), making this an ideal system for recording cies for environmental monitoring programs. For example, changes related to human activity. Compared with many investigations in Great Britain (Powe11 1 963, Johnston 1971, Norwegian fj ords, the inner Oslofjord is characterized by Russell 197 4 ), the Adriatic Sea (Munda 1 972), the Oslofjord little river input. The salinity of the fj ord varies between 15 (Rueness 1973, Bokn & Lein 1978, Bokn 1979) and the and 32 %o and the temperature fluctuates between -1 oc in Baltic Sea (Kautsky, N. et al. 1986, Kautsky, H. et al. 1992, winter to 22 oc in summer (Braarud & Ruud 1937, Gade Vogt & Schramm 1991) suggest that reductions in fucoid 1970). abundances can be correlated with environmental deteriora­ In the inner Oslofjord, five fucoid species characterize tion due to pollution. communities from the lowest supralittoral to the upper

Acta Phytogeogr. Suec. 78 118 T. L. Bokn et al.

0.25 + Fucus spiralis( • ) N • • . x Fucus vesiculasus( • x x x ) 0 4 • x x 0-t----�• Ascophyllum nodosum( Km � x x • • ) x x • • t X e e X ODD -0.25 e 0 JC ��= D�o0 o x • : o o o x • o • ooo Fucus serratus( o o • 0 o ) -0.50 0 • 0 0 0 o D o o oDo0 o0 0 0 0 0 Fucus 0o 0o evanescens( 0 D -1.00 o ) DOooo o OD 0 ogcP ODooo 0 0 OD 0 oo o ODODoD 0 �,��\ -2.00+------...30.\ '. meters

Fig. 2. The vertical distribution of the five fucoid species in the

inner Oslofjord. Note: 0 = mean low-water level.

the period of our earlier studies (1974- 1 980). These results will be discussed in terms of the concomitant changes that have occurred in the water quality within the fj ord.

Material and Methods Fig. 1. Map of the study area: the inner Oslofjord. Semi-quantitative estimates of the abundances of five fucoid species (Ascophyllum nodosum, Fucus spiralis, F. eva­ sublittoral (Fig. 2): Fucus spiralis L., F. vesiculosus L., nescens, F. serratus and F. vesicu/osus) were made at 123 Ascophyllum nodosum (L.) Le Jol., F. evanescens C. Ag. sites distributed throughout the inner Oslofjord (Figs. 3, 4) and F. serratus L. According to the earliest available records since 1974 (Bokn & Lein 1978, Bokn 1979). Surveys were (Gran 1897, Simmons 1898), F. evanescens was introduced performed once each year during April-May from 1974 into the Oslofjord about 100 years ago. Previous studies through 1980, and again from 1988 through 1990. The performed in the inner Oslofjord in the 1960s and 1970s spring period was selected for the surveys because from (Klavestad 1978, Bokn & Lein 1978, Bokn 1979) recorded March to May F. evanescens forms well-developed recep­ reductions in the standing stocks of Fucus serratus, F. tacles and is easy to differentiate from the bladderless vesiculosus and Ascophyllum nodosum together with in­ F. vesiculosus. To facilitate comparison with historical creases in F. evanescens and, to a lesser extent, F. spiralis. records, the majority of the 123 sites were identical to those Rueness (1973) and later Bokn & Lein (1978) suggested used during earlier fj ord investigations by Grenager (1957) that increases in sewage discharge into the inner fj ord had and Klavestad (1978). Where possible, fucoid abundances caused the observed changes in fucoid distributions and were determined at each site after observing a horizontal abundances, hypothetically by altering the competitive bal­ span of about 50 m of shoreline from the supralittoral down ance between perennial fucoids and ephemeral green algae. to a sublittoral depth of approximately 2 m. Abundances To determine whether recent changes in shoreline commu­ were subjectively recorded based on the following ordinal nities have occurred in the inner Oslofjord, the distributions scale: 0 = absent; 1 = low abundance; 2 = intermediate and abundances of the five species of shallow-water fucoids abundance; 3 = high abundance. became the subject of a monitoring program initiated in Since the purpose of this study is to determine changes in 1974. fucoid abundances that have occurred during the past 10-15 The purpose of this paper is to report the results of more years, results of the 197 4-1 980 and 1 988-1990 surveys were recent (1988-1990) surveys of the five fucoid species each grouped together and then compared. The ordinal data throughout the inner Oslofjord to determine whether changes were organized into species x site matrices and classifica­ in fucoid distributions and abundances have occurred since tion of the 123 sites into natural groups was determined by

Acta Phytogeogr. Suec. 78 Changes in fucoid distributions in the Oslofjord 119

OSLO

Greater tucoid =..:..::'-"'-'-'=-"' nchnessand Group o I abundance Group 11 c Group • Ill Group • IV

SITE GROUPS Greater tucoid richness and Group A Area of improvement Group I o abundance :::::::� o Group Area of reduction Group 11 B 0. Group Ill • Group IV •

Fig. 3. Distribution in the inner Oslofjord of the four site group Fig. 4. Di tribution in the inner Oslofjord of the four site groups (I-IV) interpreted from the 1974-80 data set with the aid of cluster (I-IV) interpreted from the 1988-90 data set with the aid of clu ter analysi . analysi . Area within the fj ord where sites exhibited change in ite group from 1974-80 to 1988-90 are indicated by shading.

hierarchical cluster analysis for both 1974- 1980 and 1988- over the period of study were al o identified. 1990. A constant of + 1 .0 was added to the original ordinal Additional analyses were performed to determine whether estimates to eliminate zeros allowing us to appropriately the abundance of the individual fucoid species had varied cla sify those sites that completely lacked fucoid cover. The significantly from 1974-80 to 1988-90 within the identified ordinal scores for each fucoid pecies were then summed for site groups (Groups I-IV and A-B). The ordinal data did not each site over the seven- and three-year sampling periods satisfy the requirements for parametric analysis, therefore, respectively to give greater emphasis to intermediate and the Wilcoxon paired-sample statistical procedure (Zar 1 984, high abundance values, a technique that produced the most p. 1 53) was used. All statistical tests and the cluster analyses meaningful site clusters. All classification analyses were were performed using BIOSTAT I or BIOSTAT II compu­ performed using the Bray-Curtis index and flexible sorting ter programs (Pimentel & Smith 1986, 1990).

(B = - 0.25), both of which are widely used procedures in marine benthic ecology (see Clifford & Stephenson 1975). The same four site groups (Groups I-IV) were interpreted for both of the dendrograms and these groups became the Results basis for additional statistical analyses. To determine whether or not fucoid abundances in the inner Oslofjord had varied Four site groups (Groups I-IV) were delineated within the over the study period, the two dendrograms were compared inner Oslofjord as a result of the 197 4- 1980 cluster analysis and ites interpreted to have changed clusters were identi­ (Fig. 3). Based on previous research (Bokn & Lein 1978, fied. These were separated into two new groups: sites Bokn 1979), these site groups were interpreted to represent assigned to clusters with increased fucoid richness or abun­ a gradient of fucoid richness in the inner Oslofjord with dance (Group A) and sites that were classified within clus­ Group I representing sites containing a diverse and abundant ters exhibiting reduced fucoid vegetation (Group B). Sites fucoid flora and Groups II-IV representing sites with pro­ interpreted to have remained within the same site groups gressively lower fucoid richness and abundance.

Acta Phytogeogr. Suec. 78 120 T. L. Bokn et al.

GROUP I SITES GROUP SITES in F. spiralis while maintammg high abundances of 30 11 F. evanescens (Fig. 5). In contrast, Group B sites located in 25 05 p < the lower and northeastern sections ofthe Bunnefjord, along 2.0 with a single site in the southern part of the innermost fj ord

15 branch, showed decreases in their overall fucoid vegetations

1 0 compared to 1974-80 and moved from richer to poorer site groups. These sites exhibited statistically significant 05 declines between 1974-80 and 1988-90 in four species: w Fsp1 Fves Anod Feva Fser F. spiralis, F. vesiculosus, F. evanescens and F. serratus 0 (Fig. 5). z <( 25 Statistically significant changes in the abundances of 0 certain fucoid species also occurred in Groups I and II, the z 2.0 site group determined in 1974-80 to contain the best deve­ :::J 15 loped fucoid floras, but not in Groups III and IV (Fig. 5). <(m spiralis 1.0 Increases in F. were observed between 197 4-80 and 1988-90 in both Groups I and II, concomitant with de­ 0 0 5 w . creases in Ascophyllum nodosum in Group I and F. evanes­ <(_J cens in Groups I and II (Fig. 5). 0 Fspi Fves Anod Feva Fser Fspi Fves Anod Feva Fser

(/) GROUP SITES P < .05 DECREASE8 IN QUALITY

20 Discussion

1 5 . Based on comparisons with historical records, Bokn & Lein .01 p < 1.0 (1978) and Bokn (1979) concluded from their 1974- 1977 surveys that Ascophyllum nodosum, Fucus vesiculas us and 05 F. serratus had completely disappeared from the most­ heavily polluted innermost part of the fj ord and also had Fspi Fves Anod Feva Fser Fspi Fves Anod Feva Fser experienced reductions in abundance in outer fj ord habitats. In contrast, Fucus evanescens had become by far the most Fig. 5. Abundances of the five fucoid specie in each of ix site common fucoid throughout mo t parts of the fj ord during group (I-IVand A-B)ba ed on the ordinal data ( cale =0-3). Sites assigned to Groups I-IV remained the arne between 1974-80 and the ame period, while F. spiralis showed a slight increase 1988-90 whereas sites assigned to Group A exhibited increa es in in the inner part of the inner Oslofjord. In addition, the fucoid vegetation in contrast to sites assigned to Group B which ephemeral green algae Enteromorpha spp., Cladophora showed decreases. Values plotted are the mean ±standard error for spp., Blidingia minima (Nag. ex KUtz.) Kylin and Viva 1974-80 and 1988-90, re pectively. Statistically significant differ­ lactuca L. became more abundant in the fj ord (Bokn et al. ence between mean are indicated by probability value . Fspi = 1 977). The discharge of sewage into the inner Oslofjord first Fucus spiralis; Fve = F. vesiculosus; Anod = Ascophyllum began to grow in the 1930s culminating 30 to 50 years later nodosum; Feva = F. evanescens; F er = serratus. F. in elevated organic loads in fj ord waters together with phosphorus (Fig. 6) and nitrogen levels 13 and 6 times greater than their respective discharge rates in 1910 Interpretation of the 1988-90 dendrogram revealed the (Magnusson et al. 1991). It has been asserted (Rueness same four clusters as in 1974-80, although some sites had 1973, Bokn & Lein 1978) that the changes in fucoid abun­ changed groups. A total of79 sites clustered within the same dances recorded prior to 1980 were related to deterioration site groups (I-IV) as in 1974-80, while 30 sites (Group A) in near-shore water quality due to discharged sewage. moved into clusters with greater fucoid richness and abun­ Temperature, salinity and wave exposure are known to dance; 14 sites (Group B) were reassigned to clusters char­ influence fucoid distributions and abundances in northwest­ acterized by lower fucoid richness (Fig. 4). Sites changing ern Europe and throughout the north Atlantic Ocean. Expo­ groups were used to identify those regions of the inner sure to wave action does not appear to differ significantly Oslofjord that experienced increases or decreases in fucoid throughout most ofthe sheltered waters of the inner Oslofjord. vegetation (Fig. 4). Enhanced fucoid richness and abun­ Nevertheless, the most vulnerable fucoid species to higher dance was observed in Group A sites which were located in wave energy environments in the inner Oslofjord is the northern part of the fj ord, particularly in the vicinity of Ascophyllum nodosum (Vadas & Bokn unpubl. data), al­ the Oslo harbour area, but also in the southern extremity though reduction in wave action over long periods during of the Vestfjorden near Dr!Z)bak. These sites revealed a low water can cause considerable desiccation damage to statistically significant increase from 1974-80 to 1988-90 F. spiralis (Bokn & Lein 1978, Schonbeck & Norton 1978).

Acta Phytogeogr. Suec. 78 Changes infucoid distributions in the Oslofjord 121

18 16 Tons 14 � 12

!' 10 �� 8 a 6

1910 1920 1930 1940 1950 1960 1970 1980 1990 Year Harbor Brerum Bekkelag Bun ne- Lysaker­ Vest­ basin basin basin fj ord fj ord fjord I - Phosphorus �

Fig. 6. Land-based phosphoru discharge into the inner Oslofjord for each decade from 1910 to 1990 (after BergstS(j] et al. 1981, Baalsrud et al. 1986).

Previous researcher (e.g. Levring 1940, Sundene 1953, Baardseth 1970, von Wachenfeldt 1975) have also indi­ cated that neither salinity nor temperature patterns can explain the changes in fucoid distributions and abundances Fig. 7. Concentrations of chlorophyll a in surface waters (0-2 m) that occurred around the middle of the twentieth century in and Secchi depth data for six locations in the inner Oslofjord, 1 973- the outhern Baltic Sea, the Kattegat and the Oslofjord. Ice 82 and 1 983-90. Plotted values are based on J une-August measure­ scouring in the southern part of the Bunnefjord, however, is ments and repre ent the mean ± standard error for each location. known to have reduced the abundances of Fucus spiralis, See Fig. 3 for sampling locations (after Magnusson unpubl.). F. vesiculosus and, in the upper part of its vertical distribu­ tion F. evanescens, and perhaps to have prevented the growth of Ascophyllum nodosum (Bokn & Lein 1978). (199 1) to have resulted in reduced phytoplankton standing The results presented herein clearly indicate that signifi­ stocks. This can be shown by decreased chlorophyll a cant changes in the richness and abundance of shallow­ concentrations and, based on Secchi depth measurements, water fucoid populations occurred in the inner Oslofjord increased light penetration in shallow fj ord waters over the between 1974-80 and 1988-90. However, unlike the conclu­ past 5-7 years (Fig. 7). sion of earlier studies (Rueness 1973, Klavestad 1978, Polluted fj ord waters do not restrict growth but instead Bokn & Lein 1978, Bokn 1979), based on the nature of their can lead indirectly to reduced fucoid abundances by altering fucoid vegetations most sites exhibiting change (30 of 44) the competitive balance between fucoids and ephemeral during the past decade improved in quality. The area of the algae or sessile animals in favour of the last two groups inner Oslofjord exhibiting the greatest recovery in water­ (Rueness 1973, Wennberg 1987, 1992). It is hypothesized quality parameters (Fig. 7) is also the area exhibiting the that this situation has been reversed in the inner Oslofjord greatest increase in fucoid abundances and improvement of during the last decade, due to the recorded improvements in fucoid site groups (Fig. 4). During the past decade, the water quality. Reduced abundances of green ephemeral majority of outlets that discharged sewage into the inner­ algae were observed in fj ord waters during the 1980s (Bokn most fj ord were closed in favour of a pipeline that now unpubl. observ.). Also, it is likely that declines in fucoid releases primary-treated sewage into deep water near the epiphytes and reductions in the abundances of My tilus center of the Vestfjord (Fig. 3). The released effluent is edulis L. and Littorina Littorea (L.) occurred over this period mixed with high salinity water and largely remains trapped because of the decreases in inorganic nutrients and organic below the halocline (Magnusson et al. 1991). In 1990, matter. Improvements in water clarity and reduction in phosphorus concentrations in discharged effluent were only epiphyte loads also may have favoured the four original three times those recorded in 1910 (Fig. 6) due to improved fucoid pecies at the expense of the introduced Fucus treatment practices (Magnusson et al. 1991). The enhanced evanescens, which expanded its population in the inner removal of phosphorus and the failure of nutrient-rich efflu­ Oslofjord during the 1960s and 1970s in conjunction with ent to reach surface waters is believed by Magnusson et al. increased sewage pollution. Interestingly, in contrast to the

Acta Phytogeogr. Suec. 78 122 T. L. Bokn et al. improvements in surface water quality and fucoid vegeta­ nodosum (Rueness 1 973). Unlike the otherOslofjord fucoids, tion in the inner Oslofjord, Rueness & Fredriksen (1991) the fertile period for Fucus evanescens occurs in early have recently reported a deterioration in the benthic algal spring, a time when growth of green ephemeral algae is at a communities of the outer Oslofjord due to environmental minimum. Thus, fast growing F. evanescens germling can pollution. This portrays a threat to water quality in the inner become e tabli hed in the absence of potential interference Oslofjord because of it connection with the outer Oslofjord by green algal ephemerals, whereas other fj ord fucoids, waters. which recruit during summer, cannot. This may explain Earlier, Moy ( 1985) observed that competition for sub- why F. evanescens became abundant in the more polluted tratum in the narrow (25-40 cm) littoral zone was intense regions of the inner Oslofjord during the 1960s and 1970 . between fucoid and sessile animals such as the blue mussel In addition, Fucus evanescens has been observed growing Mytilus edulis, which prior to 1985 formed thick beds in in the 0 lo harbour under lower light levels than F. serratus. inner Oslofjord areas receiving organic-rich sewage Bokn ( 1979) hypothesized that the absence of F. serratus effluent. Experimental work confirmed that thick beds of from effluent-receiving fj ord waters was caused by reduced M. edulis exclude fucoid algae other than the fa t growing light penetration. Supporting evidence for the effect of F. evanescens which reaches reproductive maturity in only reduced light penetration on fucoid distributions in polluted one year (Moy 1 985) and, therefore, preemption of space by waters has been obtained by Kautsky, N. et al. (1986) who, M. edulis may have contributed to the historical declines in by revisiting some of Wrern's localities (Wrern 1952), ob­ fucoid abundances recorded in inner Oslofjord waters served an upward progression of the lower vertical limit of (Klavestad 1978 Bokn & Lein 1978, Bokn 1979). Reduc­ the sublittoral F. vesiculosus in the Baltic Sea from the tions in the volume of sewage discharged into fj ord waters 1940 to 1984, coincident with reductions in water column has resulted in decreases in organic load and lower transparency (Kautsky, H. et al. 1992). Interestingly, inner phytoplankton standing stocks (Magnusson et al. 1991; Oslofjord populations of F. evanescens are poorly epi­ Fig. 7), and thus also may have caused a reduction in phytized, whereas eo-occurring fucoid species frequently M. edulis cover, freeing pace for fucoid colonization. carry substantial epiphyte loads (Grenager 1957). This is The five species of fucoid brown algae found in the inner particularly true in nutrient-rich harbour areas where epi­ Oslofjord occupy different vertical zones (Fig. 2) and pre­ phytes may further reduce light availability and fucoid sumably compete for space as has been demonstrated in productivity. Improvements in sewage discharge practices fj ord water by Bokn & Lein ( 1978) and on British shores by have resulted in increased light penetration in inner Oslofjord Schonbeck & Norton (1980). For example, competition waters (Fig. 7; Magnus on et al. 1991) a condition that between eo-occurring 0 lofjord populations ofAs cophyllum hypothetically would favour the growth of F. serratus. In nodosum and F. vesiculosus has been described by several addition, reduced nutrient input (e.g. phosphorus) into the authors (e.g. Baardseth 1970, Rueness 1973). In the inner­ fj ord would likely decrease the abundances of fast-growing most part of the Oslofjord, where F. vesiculas us is uncom­ epiphyte on F. serratus, as well a on the other three mon, F. spiralis appears to be more abundant compared endemic fucoids (F.vesiculosus, F. spiralis andAscophyllum with sites where both pecies are prevalent, perhaps due to nodosum). Reduced epiphyte loads would enhance growth reduced competition (Bokn & Lein 1978). and perhap favourably alter interactions between poten­ The introduced Fucus evanescens is believed to be more tially competing population of F. serratus, F. vesiculosus, tolerant of organic pollution (Sundene 1956, Powell 1957) and A. nodosum and the introduced F. evanescens. Thi than F. vesiculosus or Ascophyllum nodosum. Pre umably could lead to reduced abundance of the latter specie as F. evanescens has a competitive advantage over eo-occur­ observed in the inner Oslofjord during the 1980s. ring fucoids, including F. serratus, near sites of municipal Ephemeral green algae and fucoid germlings are known sewage discharge (Rueness 1973, Bokn & Lein 1978). to be grazed vigorously by the herbivorous gastropod However, in contrast to the polluted fjord waters, "In clean Littorina littorea where these forms eo-occur (Lein 1980, water in Shetland Islands, this plant did not mix much with Lubchenco 1983). In the inner Oslofjord where dense popu­ F. vesiculosus or A. nodosum against which it seems to be a lations of L. Littorea exist, grazing appears to be an impor­ very weak competitor" (Russell 1974, p. 68 1). Similarly, in tant factor in reducing the abundances of ephemeral algae Nova Scotia, where F. serratus has been introduced, and may also be an important means of releasing fucoid evidence suggests that F. serratus outcompetes the endemic recruits (Lein 1980), as has been demonstrated on New F. evanescens (= F. edentatus) (Dale 1982). England shores by Lubchenco (1983). However, Chapman Exten sive littoral masses of Enteromorpha spp., ( 1989), working in Nova Scotia, concluded that recruitment Cladophora spp. and other ephemeral algae can accumulate of F. spiralis germlings was not dependent on grazer activ­ in nutrient-r ich sewage-polluted waters of the inner Oslofjord ity. Grazing on adult fucoid thalli has not been observed in during warm summer months (Grenager 1957, Klavestad the inner Oslofjord (Lein unpubl. observ.) in contrast to 1978, Bokn & Lein 1978). During these periods, the highly results, for example, from the eastern North Pacific (Van productive ephemeral algae can overgrow and outcompete Alstyne 1 988, 1990). Also, fucoid species are known to vary young fucoid recruits as has been shown for Ascophyllum in their vulnerability to grazers (e.g. Barker & Chapman

Acta Phytogeogr. Suec. 78 Changes in fucoid distributions in the Oslofjord 123

1990) leading to the possibility that differential grazing Dale, M. 1982. Phytosociological structure of seaweed communi­ influences abundances of the five fucoids in the inner ties and the invasion of Fucus serratus in Nova Scotia. -Can. Oslofjord. J. Bot. 60: 2652-2658. Gade, H.G. 1970. Hydrographic investigation in the Oslofjord, a Hypothetically, reductions in nutrient and organic-rich tudy of water circulation and exchange processes. -Thesis. effluent into inner Oslofjord waters would result in de­ Univ. Bergen. 284 pp. creases in the summer growth of ephemeral algae and Gran, H.H. 1897. Kristianiafjordens algeflora. I. Rhodophycereog ultimately reduce dependent populations of Littorina littorea. Phaeophycere.-Skr. Vidensk. Selsk.. Chris. I. Mat.-Nat. Kl. An alternative outcome of reductions in the growth of 1896 (2): 1-56. ephemerals and decreases in particulate sewage organic Grenager, B. 1957. AJgological ob ervation from the polluted matter might be increased L. littorea grazing on fucoid area of Oslofjord. - Nytt. Mag. Bot. 5: 41-60. germlings. Persistence of littorinids and other grazers in Johnston, C. 1971. XV. Macroalgae and their environment. - inner Oslofjord waters in the presence of reduced abun­ Proc. Roy. Soc. Edinb. (B), 71( 15): 196-207. Jone , W.E., Fletcher, A., Bennell, S., McConnell, B. & Smith, dances of ephemerals may explain why increases in other S.M. 1979. Change in littoral populations as recorded by long fucoids have not occurred here during the 1980s despite the tenn shore surveillance. 1.Selected example of cyclic change . observed decreases in Fucus evanescens. An exception, - In: Naylor, E. & Hartnoll, R.G. (eds.) Cyclic phenomena in however, is Fucus spiralis which occurs at higher shore marine plants and animal . Pergamon Press, Oxford. pp. 93- levels than L. littorea and, therefore, has a spatial escape 100. from littorinid grazing, even in the absence of ephemeral Kautsky, H., Kautsky, L., Kautsky, N., Kautsky, U. & Lindblad, C. green algae. For Ascophyllum nodosum, apparently recov­ 1992. Studies on the Fucus vesiculosus community in the ery can take years due to the slow growth of early germlings Baltic Sea. -Acta Phytogeogr. Suec. 78: 33-48. (Sundene 1973) and the negative effects of water motion on Kautsky, N., Kautsky, H., Kautsky, U. & Wrern, M. 1986. De­ creased depth penetration of Fucus vesiculosus since the zygote attachment (Vadas et al. 1990). The responses of 1 940's indicates eutrophication of the Baltic Sea.- Mar. Ecol. grazer populations, particularly L. littorea, to alterations in Prog. Ser. 28: 1-8. sewage input into the inner Oslofjord requires further in­ KJavestad, N. 1978. The marine algae ofthe polluted inner part of vestigation before a connection between grazer effects and the Oslofjord. A survey carried out 1962- 1 966. - Bot. Mar. changes in fucoid abundances can be established. 21: 71-97. Lein, T.E. 1980. The effects of Littorina littorea (L.) (Ga tropoda) grazing on littoral green algae in the inner Oslofjord, Norway. - Sarsia 65: 87-92. References Levring, T. 1940. Studien Uberdie Algenvegetationen von Blekinge, SUd-Schweden.-Thesis. Lund Univ. I-VII + 178 pp. Baal rud, K.,Lystad,J. & Vdtle,L. 1986. Vurdering avOslofj orden. Lewis, J.R. 1976. Long-term ecological surveillance: practical - Norsk institutt for vannforskning. Rapport nr. 1922: 1-94. realities in the rocky littoral. - Oceanogr. Mar. Bioi. Ann. Baardseth, E. 1970. Synop is of biological data on knobbed wrack, Rev. 14: 37 1 -390. Ascophyllum nodosum (Linnaeus) Le Jolis. - F.A.O. Fish Lubchenco, J. 1983. Littorina and Fucus: Effects of herbivores, Synopsis 38: 1-40. substratum heterogeneity, and plant escapes during succes­ Barker, K.M. & Chapman, A.R.O. 1990. Feeding preferences of sion. - Ecology 64: 1 1 16-1 123. periwinkles among four species of Fucus. - Mar. Bioi. 106: Magnusson, J., Bokn, T. & Larsen, G. 199l.Overvaking av 113-1 18. foruren ni ngssituasjonen i Indre Oslofjord i 1 989/90. - Norsk Bergstll}l, P.O.,Feldborg, D. & Olsen, J.G. 1981. Indre OsJofjord. institutt for vannforskning. Rapport nr. 258 1. 52 pp. Forurensningstilfll}rsler 1920-80. Tilfll}rsler av fosfor. - Norsk Moy, F.E. 1985. Utbredelse av Fucus serratus L. i indre Oslofjord institutt for vannnforskning. Note. 0-7808403. 124 pp. relatert til forekomsten av Mytilus edulis L., sarnfunnsanalyse Bokn, T. 1979. Bruk av tang som overvilingsparameter i en og felteksperimenter. - Thesis. Univ. Oslo. 135 pp. nreringsrik fj ord. - In: Overviling av vattenomdiden. 15. Munda, I. 1972. Seasonal and ecological conditioned variations in Nordiska symposiet om Vattenforskning. NORDFORSK, the Fucus virsoides association from the I trian Coa t (North­ Miljll}vards sekr. publ. 1979, 2: 181-200. ern Adriatic). - Raspr. Slov. Akad. Znan. Umet. 15 (1 ): 1-33. Bokn, T. & Lein, T.E. 1978. Long-term changes in fucoid associa­ Pimentel, R.A. & Smith, J.D. 1986. BIOSTAT II. A multivariate tion of the inner Oslofjord, Norway. - Norw. J. Bot. 25: 9- 14. statistical toolbox. 2nd. ed. - Sigma Soft, Placentia, CA. 212 Bokn, T., Kirkerud, L., Krogh, T., Nilsen, G. & Magnusson, J. pp. 1977. Undersll}kelse av hydrografiske og biologiske forho1d i Pimentel, R.A. & Smith, J.D. 1990. BIOSTAT I. A univariate Indre Oslofjord. - Overvilingsprogram. Arsrapport 1975- statistical toolbox. Version 2.0. - Sigma Soft, Placentia, CA. 76. Norsk institutt for vannforskning. 0-7 1 160. 119 pp. 392 pp. Braarud, T. & Ruud, J.T. 1937. The hydrographic conditions and Powell, H.T. 1957. Studies in the genus Fucus L. II. Distribution aeration of the Oslofjord 1933-34. - Hvalr. Skr. 15: 1-56. and ecology of forms of Fucus distichus L. emend. Powell in Chapman, A.R.O. 1989. Abundance of Fucus spiralis and ephem­ Britain and Ireland. - J. Mar. Bioi. Assoc. U.K. 36: 663-693. eral seaweeds in a high eulittoral zone: effects of grazers, Powell, H.T. 1963. New records of Fucus distichus subspecies for canopy and substratum type. - Mar. Bioi. 102: 565-572. the Shetland and Orkney Islands. - Br. Phyc. Bull. 2:247-254. Clifford, H.T. & Stephenson, W. 1975. An introduction to numeri­ Rueness, J. 1973. Pollution effects on littoral algal communities in cal classification. - Academic Press, New York. 229 pp. the inner Oslofjord, with special reference to Ascophyllum

Acta Phytogeogr. Suec. 78 124 T. L. Bokn et al.

nodosum. - Helgol. Wiss. Meeresunters. 24: 446-454. Ascophyllum nodosum: wave action as a source of mortality.­ Rueness, J. & Fredriksen, S. 1991. An assessment of possible Mar. Ecol. Prog. Ser. 61: 263-272. pollution effects on the benthic algae of the outer 0 lofjord, Van AI tyne, K.L. 1 988. Herbivore grazing increases polyphenolic

Norway.- Oebalial7, Suppl. 1: 223-235. defenses in the intertidal brown alga Fucus distichus. - Russell, G. 1974. Fucus distichus communities in Shetland. - J. Ecology 69: 655-663. Appl. Ecol. 11: 679-684. Van Alstyne, K.L. 1990. Effects of wounding by the herbivorous Schonbeck, M.W. & Norton, T.A. 1978. Factor controlling the snails Littorina sitkana and L. scutulata (Mollusca) on growth upper limits offucoid algae on the shore. -1. Exp. Mar. Bioi. and reproduction of the intertidal alga Fucus distichus Ecol. 31: 303-3 13. (Phaeophyta). - J. Phycol. 26: 412-4 16. Schonbeck, M.W. & Norton, T.A. 1980. Factor controlling the Vogt, H. & Schramm, W. 1991. Conspicuous decline of Fucus in lower I imits of fucoid algae on the shore. - J. Exp. Mar. Biol. Kiel Bay (Western Baltic): what are the causes? - Mar. Ecol. Ecol. 43: 131-150. Prog. Ser. 69: 189-194. Simmon , H.G. 1898. Algologi ka notiser. II. Einige Algenfunde von Wachenfeldt, T. 1975. Marine benthic algae and the environ­ bei Drszsbak.- Bot. Not. 1898: 117-123. ment in the Oresund. I-III. - Thesis. Lund Univ. 328 pp. Smith, R.W., Bernstein, B.B. & Cimberg, R.L. 1990. Community Wrern, M. 1952. Rocky-shore algae in the Oregrund Archipelago. - environmental relationships in the benthos: applications of -Acta Phytogeogr. Suec. 30: 1-298. multivariate analytical techniques.- In: Sou le, D.F. & Kleppel, Wennberg, T. 1987. Long term changes in the composition and G.S. (eds.) Marine organism as indicators. Springer-Verlag, distribution of the macroalgal vegetation in the southern part of New York. pp. 247-326. Laholm Bay, outh-west Sweden, during the last thirty years. Sundene, 0. 1953. The algal vegetation of Oslofjord. - Skr. Nor. - Swedish Environmental Agency Report 3290: 1-47. (In Vidensk. Akad. I. Mat. Nat. Kl 1953, 2: 1-245. Swedish with English summary and legends.) Sundene, 0. 1956. A new locality for Fucus injlatus L. in southern Wennberg, T. 1 992. Colonization and succession of macroalgae on Norway. - Blyttia. 14: 67-70. (In Norwegian with English a breakwater in Laholm Bay, a eutrophicated brackish water summary and legends.) area (SW Sweden). - Acta Phytogeogr. Suec. 78: 65-77. Sundene, 0. 1973. Growth and reproduction in Ascophyllum Zar, J.H. 1984. Bio tatistica1 analysis. 2nd. ed. - Prentice-Hall nodosum (Phaeophyceae). - Norw. J. Bot. 20: 249-255. Inc., Englewood Cliff . 718 pp. Vadas, R.L., Wright, W.A. & Miller, S.L. 1990. Recruitment of

A•cta Phytogeogr. Suec. 78 Field and culture observations on Uronema curvatum Printz (Chlorophyta)

fan Rueness

Abstract Ruene s, J. 1 992. Field and culture ob ervations on Uronema curvatum Printz (Chlorophyta). -Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-721 0-078-8.

The minute green alga Uronema curvatum was originally described from the Trondheim Fj ord, Norway. It i widely di tributed on we tern and eastern coasts of the north Atlantic Ocean, but the few record uggest that it has passed unnoticed in many investigation . It typically grow on crustose red algae and on the haptera ofkelps in deep water. A summary of present record are presented, including a number of new find . An isolate from Norway was cultured and the life history involved a succession of generations by aplano pore . These were formed in the slightly swollen terminal cell (8-32 per cell). Biflagellate swarrner were occa ionally seen. Preliminary culture experiments at various tempera­ tures and salinities demonstrated best growth at 8 °C and 30 %o salinity, but growth and reproduction al o occurred at 17 °C and 20 %o. The systematic position of U. curvatum and its relationships to other uniseriate and unbranched green algae are di cussed. Cytological and other evidence suggest a removal from Ulotrichale to Cladophorales, but ultrastructural studies are required.

Keywords: Cytology; Distribution; Green alga; Life history.

J. Rueness, Department of Biology (Marine Botany), University of Oslo, P. O. Box 1069 Blindern, N-0316 Oslo, Norway.

Introduction

The minute, uniseriate and unbranched green alga Uronema the green alga U. marinum Womersley, e.g. in the list of curvatum Printz was originally described from the west species available from culture collections presented by John coast of Norway (Printz 1926). The alga was recorded as an (1984). epiphyte on the crustose red alga Peyssonnelia dubyi Crouan Only a few finds of U. curvatum have been reported since frat. (as Cruoriella dubyi) at depths between 8 and 12 m. In it was first described, and no closer examination or culture the original description the specific epithet was published studies have been undertaken. Recent investigations on the with an incorrect Latin termination (curvata) and is cor­ ultrastructure and systematics of the green algae have shown

rected here according to Art. 32.5 in Greuter et al. (1988). that the uniseriate green algae traditionally placed in the The genus Uronema Lagerheim 1887 (type species Ulotrichales comprise a heterogeneous assemblage of U. confervicolum) was distinguished from Ulothrix by the phylogenetically widely separate taxa (Mattox & Stewart colourless hemisphaerical attaching disc secreted by the 1984 ). It is not the intent of this paper to characterize the basal cell, by the short filaments of commonly elongate ultrastructural details necessary for determining the correct cells, and by the acuminate apex of the terminal cell. The taxonomic placement for U. curvatum. I report on growth latter feature is not shared by U. curvatum which was the and reproduction in culture and some cytological observa­ first marine species referred to this genus of freshwater and tions that suggest its removal from the order Ulotrichales. In terrestrial species (Pankow 1961). Later, W omersley ( 1984) addition, several new field data from the coast of Norway described a new marine species, U. marinum (as U. marina) and elsewhere are reported. from Australia which he provisionally referred to the genus Uronema because of the similarity with U. curvatum. Uronema marinum is also the name of a ciliate (Thompson 1963, Cheung et al. 1980) which has caused confusion with

Acta Phytogeogr. Suec. 78 126 J. Rueness

Material and Methods Table 1. Known records of Uronema curvatum Printz. Collection data a indicated in the cited papers.

Specimens of V. curvatum were isolated into unialgal cul­ Country Location Date Depths Reference ture by placing material of epiphytized Peyssonnelia dubyi (m) in Petri dishes with half-strength IMR culture medium Norway Trondhei msfjord ov-Mar 8-1 2 Printz (1926) (Eppley et al. 1967). Spores were produced and sporelings Norway North Cape Wrern (1958) germinated at the bottom of the dishes. These were subse­ Norway Fr�yfjorden Jan. Apr 8-3 1 Sivensen ( 1981) quently transferred to new dishes until unialgal culture orway Bergen May 15 Ruenes:. (unpubl.) ( 1990) orway Oslofjord May, Sep 5-20 Fredriksen & Rueness were obtained. Initially germanium dioxide was added to orway Vega May-Nov 5-20 Rueness et al. (unpubl.) 1 (1958) the medium (5 mg 1- ) to eliminate diatoms. Plants collected Sweden Bohu lan Oct 14- 1 8 Wrern (1992) on 26 October 1990 from Vega (county of Nordland, Nor­ Denmark Sams� area 1 2-20 ielsen & Dahl Ireland Galway, Clare, Maggs (per:.. comm.) way) formed the basis of stock cultures, but observations Antrim and Down were also made on crude cultures from other collections in N-lreland all year Maggs (pers. comm.) the same area. France Bai de Morlaix Aug Feldmann ( 1954) France Rade de Brest Aug, Sep Berger-Perrot (pers. comm.) Stock cultures were grown at 8 and 12 under a 16:8 oc oc Canada New Brunswick June -14 South et al. ( 1988) 97 ) 1ight:dark cycle. Light was provided by Phi lips TL/33 fluo­ U.S.A. Massachu etts Sep, ov 29-36 Sears & Cooper (I ( 1988) rescent tubes at a photon fluence rate of ea. 50 jlmolphot ons U.S.A. Gulf of Maine 24-33 Vadas & Steneck m-2 s-1 • A preliminary culture experiment was carried out to test for growth and survival at various salinities and tem­ peratures. Filaments were incubated at temperatures rang­ ing from 5 oc to 25 oc on a temperature gradient growth table at 20 %o and 30 %o salinities. Nuclei were observed by epifluorescence rnicroscopy member of an as emblage of algae dominated by crustose after microwave fixation in 1 jlg ml-1 DAPI ( 4 ',6-diamidino- Corallinaceae and various non-calcified red and brown 2-phenylindole) in the sea-water medium (Goff & Coleman crusts and shell-boring species (e.g. Ostreobium, Concho­ 1990). After mounting in fre h DAPI-sea-water solution, celis). This community is distributed over extensive areas in the alga was examined with a Leitz Orthoplan microscope northern Norway where larger algae are suppre sed due to fitted with a Leitz vertical illuminator and filter combina­ grazing by high densities of the green sea-urchin Strongylo­ tion (Ploemopak fi lterblock A). centrotus droebachiensis O.F. Muller, and is similar to that Material for electron micro copy was fixed in 1.5 % de cri bed as 'urchin-barren-ground' by Himmelman ( 1986). glutaraldehyde in sea-water for 24 h and po t-fixed in 2 % V. curvatum occurs also as an epiphyte on larger red algae uch as Turnerella pennyi (Harvey) Schmitz and Odonthalia 0 0 in 0. 1 M cacodylate buffer (pH = 7.4). The fixed 4 dentata (L.) Lyngbye. The alga ha been recorded in every material was wa hed for 2 x 10 min. in a buffer solution prior to ethanol dehydration and embedding in Spurr' month of the year, but most observation are from the winter half of the year. It typically form dense colonies that are medium. Polymeri ation lasted 24 hat 70 oc. Section were cut (ea. 50 nm thickness) with a diamond knife and tained vi ible to the naked eye, even though each fi lament is with saturated uranyl acetate and lead citrate solution. The usually less than 0.3 mm in length. sections were examined in a JEOL 100 C transmission Uronema curvatum is an inconspicuous alga that has electron microscope (TEM). probably passed unnoticed in many investigations. Aware­ ness of its micro-habitat on fleshy red crusts may aid in the recognition of this distinctive species as being more com­ mon than the paucity of records indicates. The alga was not included in the recently published 'Seaweeds of the British Observations and Discussion Isles' (Burrows 1991), but according to Maggs (pers. comm.) it is rather common on red crusts in Ireland and Northern Field observations Ireland (Table 1). On the American east coast the alga appears to have its southern limit in Massachusetts. The find After its description V. curvatum has infrequently been reported by William (1948) from North Carolina has been reported but it appears to be widely distributed on both sides excluded by Schneider & Searles (199 1) since no voucher of the north Atlantic Ocean (Table 1). specimen can be located and it has not been recollected in Most records have been made from the lower part of the the region. sublittoral zone where V. curvatum most frequently has Reproductive structures were not described by Printz been found on non-calcified crustose red algae (e.g. (1926) for V. curvatum, but he referred to emptied terminal Peyssonnelia and Cruoria), on pebbles and shell bottom cells with an opening that he considered to be sporangia. and on the haptera of Laminaria hyperborea (Gunn.) Foslie. Feldmann (1954) mentioned the occurrence ofzoospores in At Vega (northern Norway) V. curvatum is a characteristic the specimens collected in August, but did not give any

Acta Phytogeogr. Suec. 78 Observations on Uronema curvatum 127

-- a \

-- 9

d e -f -h

Fig. l. Uronema curvatum Printz in culture,( a) habit of species, crowded group of curved fi laments, the largest with terminal sporangia, cale = 25 �m, (b)-(c) apical portion offilament in bright field (b) and fluore cence (c) microscopy showing two nuclei in each cell, cale = 5 �m, (d)-(e) terminal porangia before (d) and after (e) release of spore through a pore in the wall (arrow), scale = 10 �m, (g) spore with two flagella, scale = 5 �m, (f),(h), (i), germination of spore , attached with a di c (f)or producing a long rhizoid (h),(i). The sporeling in (i) germinated in situ in the sporangium with the rhizoid through the pore, cale = 10 �m. U) fluore cence microscopy showing intercalary vegetative cell with 8 nuclei, scale = I 0 �m.

details of sporangia or spores. In the field-collected mate­ length of ten cells, but occasionally, and especially in non­ rial from Norway, emptied sporangia have been observed in attached filaments, growth may continue, and coiled fila­ November and May, but no release of spores or gametes ment con si ting of up to 100 cells may form. On maturation was seen in field-collected plants. the terminal cell becomes slightly swollen and 16-32 spores are formed (Fig. 1 d). These are released through a pore in the upper part of the cell, and always on the outer face Culture observations relative to the curvature of fi laments (Fig. 1 e). The emptied cells soon disintegrate and subapical cells may become Uronema curvatum grows well in unialgal culture in poly­ reproductive. The spores that have been observed are rounded styrene Petri dishes, hence it appears to be independent of and 5 IJ.m in diameter. In some instances 2 terminally the basiphyte that it is usually associated with in the field. inserted flagella have been observed on cells (Fig. 1 g) that The alga maintains its typical growth form in culture, with are released from the sporangia, but most frequently no the characteristic curved fi laments (Fig. 1 a-b). Usually the flagella are seen and the spores appear to be aplano pores. It alga becomes reproductive before the filaments reach a may be that the flagella are easily lost, perhaps as a culture

Acta Phytogeogr. Suec. 78 128 J. Rueness

Fig. 2. TEM section of cell showing starch grains 2 in the chloroplast, cale bar = 1 J.lm.

artefact. Spores germinated in-situ spores are frequently authentic material has been preserved on which thi feature een (Fig. 1 i). could be verified. The material investigated in the present Spores germinate immediately in culture, and numerous study is in good accordance with the description by Printz plantlets are produced around the mother-plant, suggesting (1926) with respect to vegetative and ecological features, that the spores settle directly on the bottom without swim­ but the number of nuclei in vegetative cells vary from 1 to 8 ming away. Spores that attach to the bottom produce an (Fig. 1 c, 1 j). The DAPI staining gave excellent results and attachment disc, while non-attached spores produce a long demonstrated that 2 nuclei frequently occur in each cell and unbranched rhizoid (Fig. 1 h-i). The direction of the (Fig. 1 c). Prior to the differentiation of the apical and curvature of filaments is random and appears not to be the subapical cells into sporangia, 8-16 (occasionally 32) nuclei result of e.g. phototropism; it is rather a re ult of the are present. intercalary cell divisions and cell elongation. The chloroplast is parietal and lobed and occupies most of The preliminary culture experiments at various tempera­ the cell wall. No pyrenoids are visible in the light-micro­ tures and salinities demonstrated best growth at 8 oc and 30 scope, as pointed out by Printz (1926). Some preliminary %o S; slightly less growth occurred at 12 oc. At 17 oc TEM sections of cells have demonstrated that starch grains growth was poor, but spores were formed and germinated, are present inside the chloroplasts (Fig. 2) but no pyrenoids. while the alga did not survive temperatures of 21-22 oc. A It appears from the sections that more than one chloroplast salinity of 20 %o (at 12 °C) was suboptimal but not lethal. may be present in each cell, but more sections are required Some growth occurred and spores were formed and germi­ to determine this with certainty. nated, but the cells became irregular in form and many cells . were dead, as was demonstrated by staining with Evans blue. Related species and systematic position

Womersley (1984) described another marine species of Cytological observations V ronema, V. marinum, from southern Australia. This alga resembles V. curvatum in size and cell dimensions, but In the original description of Uronema curvatum Printz differs in having a prominent pyrenoid (rarely two) in each ( 1926) the alga is claimed to be uninucleate, in accordance cell. Nothing is known of the number of nuclei in vegetative with the description of the genus and the traditional concept cells, but the placement in the order Ulotrichales suggests of Ulotrichales. Unfortunately, no type specimen or other uninucleate cells. The habitat also differs: V. marinum

Acta Phytogeogr. Suec. 78 Observations on Vronema curvatum 129

occurs as an epiphyte on Chaetomorpha and Pterocladia in British Isles and France, respectively. The keeper of the shallow water, while V. curvatum seems to be restricted to Naturhistoriska Riksmuseet, Stockholm is thanked for the crustose red algae in deep water. loan of Chaeteomorpha sphacelariae and Professor I. The fi nding that V. curvatum as studied in the present Wallentinus for the loan of type material of Vrospora investigation is multinucleate, indicates that related species microscopica Levring from the Department of Marine may be found within the genera Chaetomorpha, Rhizo­ Botany, University of Goteborg. clonium and Vrospora. Vrospora microscopica Levring (1937) was described from the Norwegian west coast and is not known outside the type locality where it was only found once. This alga was References growing epiphytically on Nitophyllum punctatum (Stackh.) Grev. and on Cystoclonium purpureum (Huds.) Batters in a Burrows, E.M. 1991. Seaweeds of the British Isles. Vol. 2 locality (Osund north of Bergen) with maerl and shell Chlorophyta. - Natural History Museum Publ., London. 238 bottom similar to that typical for the habitat of V. curvatum. pp. Cheung, P.J., Nigrelli, R.F. & Ruggieri, G.D. 1980. Studies on the Cell and thallus dimensions of V. microscopica (cells 10-20 morphology of Uronema marinum Dujardin (Ciliata: 11m in diameter and length of fi laments up to 1.75 mm) Uronematidae) with a description of the histopathology of the differ from those recorded in V. curvatum. According to infection in marine fishes. - J. Fish. Diseases 3: 295-303. Levring (1937), the parietal chloroplast contains several Eppley, R.W., Holmes, R.W. & Strick.Jand,J.D.H. 1967. Sinking pyrenoids. The sporangia are formed from apical cells rates of marine phytoplankton measured with a fluorometer. ­ similar to what is fo und in V. curvatum, but examination of J. Exp. Mar. Biol. Ecol. 1: 191-208. the type material of V. microscopica demonstrated that in Feldmann, J. 1954. Inventaire de la flore marine de Roscoff. addition to the differences in cell dimensions, the spores are Algues, champignons, lichens et sperrnatophytes. - Trav. released through a lateral pore in the cell wall, while in Station Biol. Roscoff. 1954 (Suppl.): 1-152. Foslie, M. 1881. Om nogle nye arctiske havalger. - Christiania V. curvatum the pore is subapical. In addition, the filaments Vidensk.-Selsk. Forh. 1881 no. 4: 1-14. of V. microscopica are not or only slightly curved. It is Fredriksen, S. & Rueness, J. 1990. Benthosalger i Ytre Oslofjord. therefore concluded that two separate species are involved. - Rappmt 397/90. Statens forurensningstilsyn. 63 pp. (Mimeo­ The alga described as Chaetomorpha recurva by Scagel graphed.) ( 1966) appears to be related, but differs somewhat in cell Goff, L.J. &Coleman,A.W. 1990. DNA: Microspectro-fluorometric and thallus dimensions (cells having a diameter of6- 10 !J.m studies. In: Cole, K.M. & Sheath, R.G. (eds.) Biology of the and a length of 18-30 !J.mand filaments being up to 2 cm in red algae. pp. 43-73. - Cambridge University Press, Cam­ length). Other minute Chaetomorpha species include C. bridge, New York. sphacelariae Foslie (1881). This alga was described from Greuter,W., Burdet, H.M., Chaloner, W.G., Demoulin,V., Grolle, R., Hawksworth, D.L., Nicolson, D.H., Silva, P.C., Stafleu, Honningsvag, Norway as an epiphyte on Sphacelaria. From F.A., Voss, E.G. & McNeill, J. (eds.) 1988. International code examination of type specimens and the differences in cell of botanical nomenclature, adopted by the fourteenth Interna­ dimensions and habitat, it is concluded that the alga cannot tional Botanical Congress, Berlin, July-August 1987. - be associated with V. curvatum. Regnum Veg. 118: 1-328. The multinucleate vegetative cells in V. curvatum suggest Himmelman, J .H. 1986. Population of green sea-urchins on rocky that the alga may be related to the 'Acrosiphonia group' barrens. - Mar. Ecol. Progr. Ser. 33: 207-2 16. within Ulotrichales sensu O'Kelly & Floyd (1984) or to the John, D.M. 1984. On the systematics ofChaetophorales. In: Irvine, Cladophoraceae within the order Siphonocladales. The D.E.G. & John, D.M. (eds.) Systematics of the Green Algae. 'Acrosiphonia group' appears to be the least probable since pp. 207-232. - Systematics Association Special Volume 27. Academic Press, London and Orlando. a Codiolum phase as is typical in the life history of these Levring, T. 1937. Zur Kenntnis der Algenflora der norwegischen genera was not demonstrated in this culture study. It cannot Westktiste. - Acta Univ. Lund. N.F. Avd. 2, 33: 1-148. be excluded, however, that only part of the life history has Mattox, K.R. & Stewart, K.D. 1984. Classification of the green been expressed in culture. algae: A concept based on comparative cytology. pp.29-72. In: Ultrastructural studies of mitosis and cytokinesis and of Irvine, D.E.G. & John, D.M. (eds.) Systematics of the Green the structure of motile cells are required before an assess­ Algae. - Systematics Association Special Vol. No. 27. Aca­ ment can be made of the taxonomic relationships between demic Pre s, London and Orlando. V. curvatum and the morphologically similar species men­ Nielsen, R. & Dahl, K. 1992. Marine algae south of the island tioned above. Vejr(j, the Sams(jarea, Denmark. - Acta Phytogr. Suec. 78: 111-116. O'Kelly, C.J. & Floyd, G.L. 1984. Correlations among patterns of porangial structure and development, life histories, and Acknowledgements. I am indebted to Dr. Charles O'Kelly ultrastructural features in the Ulvophyceae. In: Irvine, D.E.G. who first directed my interest to re-investigating V. curvatum. & John, D.M. (eds.) Systematics of the Green Algae. pp. 121- Drs. C.A. Maggs and Y. Berger-Perrot kindly provided 156. - Systematics Association Special Vol. No. 27. Aca­ information on unpublished finds of V. curvatum from the demic Press, London and Orlando.

Acta Phytogeogr. Suec. 78 130 J. Rueness

Pankow, H. 1961. Die Algengattung Uronema Lagerh. - Arch. 305 pp. Protistenk. 105: 117-130. South, G.R., Tittley, I., Farnham, W.F. & Keats, D.W. 1988. Printz, H. 1926. Die Algenvegetation des Trondhjemsfjordes. ­ A survey of the benthic algae of outhwestern New Brunswick, Skr. Norske Yidensk. - Akad. Oslo I. Mat.- Nat. KJ. 5: 1-273, Canada. - Rhodora 90: 419-45 1. pi. 1-lO. Thomp on, J.C. Jr. 1963. A rede cription of Uronema marinum Scagel, R.F. 1966. Marine algae of Briti h Columbia and northern and a propo ed new family Uronematidae. - Virginia J. Washington, Part I: Chlorophyceae (green algae). - National Science 15: 80-87. Museum of Canada, Bull. no. 74, Bioi . Ser. 74: 1-257. Yadas, R.L. & Steneck, R. S. 1 988. Zonation of deep water benthic Schneider, C.W. & Searles, R.B. 1991. Seaweeds of the southeast­ algae in the Gulf of Maine. - J. Phycol. 24: 338-346. ern United States. Cape Hatteras to Cape Canaveral.- Duke Wcern,M. 1958. Phycological investigations of the Swedish west University Press, Durham and London. 553 pp. coast. I. Introduction and tudy of the Gaso shell-bottom. - Sears, R. & Cooper, R.A. 1978. De criptive ecology of offshore, Sven. Bot. Tidskr. 52: 319-342. deep-water, benthic algae in the temperate we tern North Williams, L.G. 1948. The genus Codium in North Carolina. - Atlantic Ocean.- Mar. Bioi. 44: 309-3 14. J. Elisha Mitchell Sci. Soc. 64: 107-116. Si vertsen, K. 1981.Al gevegetasjonen i Fr�yfjorden, S�r-Tr�nde1ag. Womersley, H.B.S. 1984. The Marine Benthic Flora of Southern - Cand. Real. Thesi . Univ. 0 1o. 305 pp. (Mimeographed.) Australia. Pt. I. -Govt. Printer, South Au tralia. 329 pp.

Acta Phytogeogr. Suec. 78 The gradient of the benthic algal vegetation along the eastern Icelandic coast

lvka M. Munda

Abstract Munda, I. M. 1992. The gradient of the benthic algal vegetation along the eastern Icelandic coast - Acta Phytogeogr. Suec. 78, Uppsala. ISBN 91-72 10-078-8.

The Icelandic ea t coast is urrounded by cold, low-salinity water of arctic origin, contrary to other parts of the Icelandic coast, where Atlantic water infl uences prevail. The East Icelandic Current meets the North Icelandic Irminger Current and other water mas es from the northern Icelandic shelf in the northeast. Along this area the vegetation pattern changes gradually, reflecting a wide hydrographic mixing area between different water masses. Typical Atlantic water species (Corallina of ficina/is, Mastocarpus stellatus, Cystoclonium purpureum, Ceramium spp.) disappear along the coastline between Melrakkasletta and Vopnafjordur. In the mideast, between Seydisfjordur and Berufjordur, the East Icelandic Current had the strongest influence on the vegetation. Thi area is characterised by the lowest yearly water temperature averages and lowest temperature maxima during summer in Iceland and creates conditions for the development of a typical subarctic vegetation. Typical associations are the vertically extended belts of Ulothrix spp.-Urospora penicillifo rmis in the eulittoral; the low eulittoral belts of Devaleraea ramentacea, Chordariaflagelliformis with Chorda tomentosa, Porphyra thulaea, Enteromorpha groenlandica withAcrosiphonia arcta, and wide meadows of several Acrosiphonia species; and the mixture of everal subarctic and arctic species such as Pantoneura baerii, Laminaria nigripes and Porphyra miniata var. amplissima in the sublittoral vegetation. In the southeast the limit between cold arctic and warm Atlantic water masse is sharply defined, but submitted to easonal and annual translocations. Here, a rather abrupt floristic and vegetation limit was observed in the vicinity of the frontal zone.

Keywords: Algal association; Hydrographic influence; Species distribution; Subarctic vegetation; Zonation pattern.

I. M. Munda, Biological Institute, Slovenian Academy of Science and Arts, 61000 Lj ubljana, Slovenia.

Introduction Contrary to the rest of the Icelandic coast, the eastern area is surrounded by cold, low-salinity water, conveyed by the East Icelandic Current. This current has its origin near the The Icelandic coast (Fig. 1) is an area of large hydro graphic Scoresby Sound, East Greenland, and enters the Icelandic contrasts, which are reflected in the benthic algal vegeta­ coastal area north of Melrakkash�tta in the northeast tion. Iceland is surrounded by water masses of widely (Stefansson 1962, Munda 1991, Fig. 5.4). North of the different origins and characters. Most of the coast is influ­ peninsula of Langanes it bends towards southeast and fol­ enced by Atlantic water masses, which are conveyed from lows the Icelandic east coast to the area between Eystrahorn the southeast along the south coast and by the Irminger and Vestrahorn, where it meets warm and saline Atlantic Current to the northeast. One branch of this current enters water. The boundary between the two water masses is the Icelandic north coast and follows the slopes of the shelf usually sharply defined, but submitted to seasonal and towards the northeast. The eastwards flowing Atlantic wa­ annual translocations. ter is submitted to mixing processes with other primary and Differences in the benthic algal vegetation of Iceland's secondary water masses and gets gradually cooled and hydrographic districts are most pronounced in the lower diluted during its passage over the insular shelf (Stefansson eulittoral of exposed, open rocky sites (e.g. Stromfelt 1886, 1962). J6nsson 1910, 1912, Munda 1972, 1975, 1978a, 1978b,

Acta Phytogeogr. Suec. 78 132 /.M. Munda

Melrakkasletta

Grimsey ---- 0

1 �Vopnafj ordur · :.,.....--- Herads06i · · Seydisfjordur / ��V __r--Ij 6ifjordur · . � Sele> Iceland - - �Reyctarfjorctur . �� attarncs Alftaf .�"\. jordur -...... _Fa krudsfjordu r Eystrahorn::::::::--... \\ llvalnes�(\ \ Stad\'arfjordur dur

�- . -:...· �\ �� ::::: !: .. Lo: \(Vestrahorn J \ Stokksne Ing61fshlifcti l ,..-� Ho�rnafjordur llrollaugseyjar Fig. I. Map of Iceland with areas inve tigated.

1980, 1983, 1987, 1991)aswell as in the tide pools (Munda studied; in the midea t, the vegeta tion of Mj6ifjordur, 1975, 1981). Along the south, southwest and northwest Reydarfjordur, Faskrudsfjordur, Stodvarfjordur and coasts, which are influenced by Atlantic water masses, Berufjordur. In the southeast detailed studies were carried Mastocarpus stellatus (Stackh.) Guiry, Callithamnion out along open areas between the landlocked fj ords of sepositum (Gunn.) Dixon et Price, and Corallina officinalis Alftafjordur, L6nsfjordur and Hornafjordur (Fig. 1). L. form belts in this zone between the fucoids and the kelps. Within the fj ords the algal vegetation differed from that of In the hydrogra phic mixing area of northern Iceland, these the open east coast, because of reduced tidal movements and belts are replaced by Devaleraea ramentacea (L.) Guiry, estuarine conditions (cf. Munda 1978b). Special attention Chordariajlagelliormisf (O.F. Mtill.) J. Ag., and exten ive wa paid to the surrounding of the hydrographic boundary meadows of diverse Acrosiphonia species. Only the penin­ area viz. Eystrahorn (Hvalnes) and Vestrahorn (Stokksnes), sula of Tj ornes in the northeast repre ents an enclave of north and south of the front, respectively. The open fj ords in typical Atlantic vegetation, with exten ive meadows of the mideast were studied along their entire coa tline . In Corallinaof ficinalis mixed with some warm boreal species inner and middle fj ord areas the benthic algal vegetation i still estuarine and similar all around the Icelandic coast (cf. such as Asperococcus fistulosus (Huds.) Hook. The tide-pool vegetation of the north coast till bears Munda 1972, 1978a, 1978b, 1983). The differences in the Atlantic features, with associations of Corallina of ficinalis, vegetation of Iceland's main hydrographic districts thus Ceramium spp., Cystoclonium purpureum (Huds.) Batters primarily are obvious in the outer fj ord areas and along the and Dumontia contorta (Gmel.) Rupr. occurring side by open coastlines between them. side with cold water tide-pool associations of Devaleraea ramentacea, Chordariajlagelliformis and otherfilamentous brown algae as well as several species of Acrosiphonia. Hydrographic conditions Contrary to the rest of Iceland, the east coast provides conditions for the development of a typical subarctic veg­ Between Jan Mayen (71 o N, 9° W) and the northeast of etation (Stromfelt 1886, J6nsson 1910, 1912, Adey 1968, Iceland an anti-clockwise circuit is formed, which feeds Munda 1972, 1975, 1983, 1991). This contribution deals water to the arctic East Icelandic Current (Stefansson 1962, with the main vegetation features along the Icelandic east Munda 1991 Fig. 5.4). In addition this current is mixed with coast and their hydrographically controlled variations. Spe­ water masses from the North Icelandic Irminger Current, cial attention was paid to the floristic composition of the the East Greenland Current, some polar water and the so­ leading algal associations and to zonation patterns. The called North Icelandic Winter Water, which is formed on study was carried out during the summer and autumn months the northernIcel andic shelf during winter. The EastIc elan­ from 1965 to 1980 along a latitudinal range from 64° 12' N dic Current wasan ice-free arctic current between 1948 and to 66° 30' N. In the northeast, the vegetation of Melrakka­ 1963. Later, between 1965 and 1970, however, it advanced sletta, the peninsula of Langanes and of Vopnafjordur were further south and westwards and developed into a polar

Acta Phytogeogr. Suec. 78 Benthic algal vegetation 133

Table 1. Temperature and salinity measured by the author in ome areas along the Icelandic east coast including yearly average water temperatures (from Stefansson 1969).

Part of coast Area incl. Site Temperature Salinity month, year yearly average oc %o temperature °C

NE Iceland Melrakka letta Sveinungsvfk 5.8 33. 1 October 1965 4.4 Kollavfk 4.0 32.9

NE Iceland Langanes Th6rsh0fn 7.4 32.6 August 1965 4.2 Lam banes 6.2 32.0 Heidarnes 6.0 33.8 Skalane 4.6 33.9

NE Iceland Vopnafjordur Sandvfk 9.0 29.0 Augu t 1965 4.3 Vopnafjordur 7.0 33. 1 Grenisoxl 6.5 32.7 Vindfell 5.2 34.0

E lceland Reydarfjordur Kolmulf 4.5 33.7 Augu t/September 1965 outer area Vattarnesb6t 4. 1 33.4 3.9 Vattarnes 3.5 34.0 Bakur 3.1 34.2 Vattarnesskridur 3.0 34.7 Hafnarne 3.0 34.7

E Iceland Berufjordur, Teigarhorn 7.0 30.8 August/September 1968 outer area Framnes 5.7 32.2 4.0 Sandbrekkuvfk 6.5 31.5

N fj ord coa. t Nupstangi 3.9 33.0

8.2-8.5 3 .9-32.9 E Iceland Berufjordur, Urdateigur I 968 7.6 30.3 August/September I middle area Teigartangi

SE lceland Ey trahorn, Hvalnes 5.8 33.4 August 1968 of frontal zone Kro snes 5.6 33.3 4.7 Baejar6 en 6.3 33.0

SE Iceland Ve trahorn Stokksnes 8.5 34.2 Augu t 1968 S of frontal zone Hafnarnes 8.2 34.4 5.8

current, transporting drift ice (Malmberg 1969, 1972, 1984, far outh as to Hornafjordur or even further southwest Malmberg & Stefansson 1972). (Malmberg & Stefansson 1972, Stefansson 1972). As a The penetration of drift ice is a crucial factor influencing result, annual translocation of the frontal zone were espe­ the hydrographic conditions along the north and east coasts cially pronounced in 1965, 1967 and 1968. After 1970 ice (Einarsson 1969, Sigtryggsson 1972). The so-called 'north conditions became less severe, but in the late 1970s drift ice ice' is driven by easterly winds between Greenland and appeared again (Malmberg 1984). During the winter of Iceland. The margin of the compact ice is then moved 1980 unusual conditions were found, with relatively high further east and toward the Icelandic coa t. The 'east ice' is sa1inities and temperatures within the East Icelandic Cur­ a result of the extension of the 'north ice', when a tongue of rent. Besides annual also seasonal translocations of the compact ice reaches the East Icelandic Current. During frontal zone have been reported (Malmberg & Stefansson severe ice years, the drift-ice border may extend from 1972). The shift in the extension of the East Icelandic Langanes to Jan Mayen and the most unfavourable ice Current is, according to Lamb ( 1979), one of the most conditions were found just northeast ofLanganes (Malmberg important and interesting aspects of climatic changes in 1984). present and historical times, which is reflected also in the Severe ice conditions were found in the northern and benthic algal vegetation of this coast. eastern Icelandic waters in the late 1960s, after a long ice­ Along the east coast yearly temperature averages from free period. During these years a tongue of cold, low­ 1949 to 1966 (Stefansson 1969) declined from Melrakka­ salinity water, resulting partly from melting ice, extended as sletta towards mideast and increased again further south

Acta Phytogeogr. Suec. 78 134 !.M. Munda

surface-water salinity. Low temperature values, 3.0-4.6 °C, were found in the outermost fj ord regions in August 1965 a • Melrakkash�tta well as in August 1975. Low temperature values were also 9 o Langanes found in the outer area of Mj6ifjordur in the summers of • Reyaartjorour 8 1965 and 1975. Some hydrographic data for the northeast, mideast and southeast coa ts are given in Table 1. On the open coa t around Melrakkasletta urface water tempera­ 6 ture varied between 4 and 6 oc in October 1965, but were

5 higher in the frequently occurring landlocked bays in the area. 4

3

The benthic algal vegetation

Northeastern area (Melrakkasletta-Vopnafjordur)

Ill IV V VI VII VIII IX X XI XII months Vegetational differences between the extreme northwest T(OC) and the extreme northeast of Iceland are quite conspicuous, 10 • Papey but not outstanding, since both areas belong to the same, i.e. 9 o Eystrahorn the north Icelandic, vegetation type. However, there are fewer Atlantic species in the northeast. Since the area i 8 subjected to hydrographic mixing, there is also a gradual transition to the east Icelandic vegetation type. Individual

6 species, as well as associations, disappear gradually and some new species and associations are added.

4 Melrakkasletta Around Melrakkasletta, open coasts alternate with land­ locked bays and the benthic algal vegetation of thi penin­ sula i mostly limited to wide, rocky slopes. The vegetation of the open coa t still ha northern features, although the Atlantic character of the vegetation was reduced. The slopes were covered by fucoids in their usual vertical sequence: I Ill IV V VI VII VIII IX X XI XII Fucus spiralis L. above F. vesiculas us L. and Ascophyllum months nodosum (L.) Le Jol., which in turn were fo llowed by F. distichus L. spp. edentatus (De la Pyl.) Powell. Asco­ Fig. 2. Average monthly water temperatures in ea tern Iceland phyllum nodosum is the main fucoid on moderate rocky (afterStefansson 1969). slopes in thi area, while it i extremely rare along the entire north coast. At highly exposed sites (e.g. in the bays of Sveinungsvik: and Kollavfk) Fucus distichus ssp. anceps (Table 1). Monthly temperature averages from the same (Harv. et Ward. ex Carruthers) Powell was the only fucoid period (Stefansson 1969) exhibited pronounced differences present, locally very small and unusually narrow. between the sites (Fig. 2), whereas the yearly temperature In the tide pools, Corallina off icinalis with epiphytic minima generally were fairly uniform. Temperature maxima Leathesia difformis (L.) Aresch. was till commonly found were found in July-August between Melrakkasletta and along with the other Atlantic water associations of Cysto­ Heradsfl6i (Vopnafjordur); in August-September further clonium purpureum, Ceramium spp. and Dumontia contorta. south along the east coast. Temperature minima were usu­ In the upper eulittoral, broad and prolific belts of Porphyra ally found in March-April and were similar all the way from umbilicalis (L.) J. Ag. were common around Melrakkasletta, Melrakkasletta to the mideast. A progressive temperature as well as around the neighbouring peninsula of Tj ornes. increase was obvious along the line of the frontal zone. The high level belt of Ulothrix spp.-Urospora penicillifo rmis During the severe ice years of 1965 and 1968, temperature (Roth.) Aresch. was narrow and inconspicuous. In the lower and salinity data were collected simultaneously with algal eulittoral a mixed belt of the codominants Devaleraea sampling. In Reydarfjordur (Munda 1983) there was a ramentacea-Palmaria palmata (L.) Kuntze - Rhodomela decline of the surface-water temperature from the head to lycopodioides (L.) C. Ag. commonly occurred, whereas the mouth of the fj ord, with a simultaneous increase of the pure D. ramentacea belts were relatively rare. Acrosiphonia

Acta Phytogeogr. Suec. 78 Benthic algal vegetation 135

Fig. 4. Belt of Acrosiphonia spp.with scattered Fucus distichus, from Berufjordur (Urdateigur), eastern Iceland.

cold-water masses compared to the conditions around Melrakkasletta further north. This was especially true dur­ ing the unfavourable ice years, with drift ice between Langanes and Jan Mayen. Several floristic and vegetational differences from the Fig. 3. Lower level of the Devaleraea ramentacea belt together area around Melrakkasletta were obvious. Corallina offici­ with A/aria esculenta off Reydarfjordur, eastern Iceland. nallis, till prolific in the tide pool around Melrakka letta, was rare at Langanes, a was Dumontia contorta. At Langanes Ceramium spp. and Cystoclonium purpureum were still species were mainly limited to the understorey of fucoids prolific, but cold-water tide-pool as ociations predominated. and did not form eparate belts in thi particular area. A In this area the brown alga Coilodesme bulligera Stromf. scattered occurrence of Mastocarpus stellatus in the lower joined the vegetation. It was common in mid eulittoral tide eulittoral was characteristic of this area. On a few, highly pools, attached to Ralfsia fungiformis (Gunn.) Setch. et expo ed promontories, belt of Chordaria flagellifo rmis Gardn. The latter specie increased in abundance compared were found, a feature shared with the subarctic vegetation of to the surroundings of Melrakkasletta and the north coast a the mideast. a whole. Coastal lagoons were populated by Saccorhiza In the upper sublittoral, belts of Laminaria digitata (Huds.) dermatodea (De la Pyl.) J. Ag. Larnour. f. stenophylla alternated with belts of Alaria In the upper eulittoral, the belt of Ulothrix spp.-Urospora esculenta Grev., a vegetation pattern which is unusual on penicillifo rmis showed a conspicuous vertical expansion, the north coast, where Alaria belts predominate. Within while the Porphyra umbilicalis belt was uncommon. In the sheltered bays, broad and undulated forms of both L. digitata lower eulittoral, pure belts of Devaleraea ramentacea domi­ and L. saccharina (L.) Lam. were characteristic. nated on moderately sloping rocks (cf. Fig. 3) and belts of The landlocked bays had an estuarine vegetation of di­ Chordaria flagellifo rmis on steep, highly exposed rocks. verse fi lamentous brown and green algae such as Entero­ Belts of Petalonia species [P. fa scia (O.F. Miill.) Kuntze, morpha spp., Cladophora spp., Ectocarpus spp., Dictyo­ P. zosterifolia (Reinke) Rosenv.] were rather common higher siphon spp., Pilayella littoralis (L.) Kj ellm., Chordaria in the eulittoral than Chordaria. Species of Acrosiphonia flagelliformis, Eudesme virescens (Carm. ex Harv. in Hook.) were better represented than around Melrakkasletta and C. Ag. and Chorda filum (L.) Stackh. formed dense populations at different levels in the eulittoral (cf. Fig. 4), including the tide pools. In this area neither Langanes Mastocarpus stellatus nor Leathesia dif.formis occurred in The peninsula of Langanes is under intensified influence of the vegetation.

Acta Phytogeogr. Suec. 78 136 IA4. A1unda

Fig. 5. Alaria esculenta beds outside Reydarfjordur (Vattarnes), eastern Iceland.

In the upper subli ttoral Alaria esculenta dominated in its and Chordariaflagelliformis, Dictyosiphon spp., Ectocarpus narrow growth form, as it usually does along the north and siliculosus (Dillw .) Lyngb., Petalonia spp. and Scytosiphon east coasts (Figs. 3 and 5). In the lower sublittoral of these lomentaria (Lyngb.) Link. in the lower pools. transitional areas forests of Laminaria hyperborea (Gunn.) In the upper eulittoral it was noteworthy that the high­ Foslie were usually found, followed by Desmarestia aculeata level belt of Ulothrix spp.-Urospora spp. was even broader (L.) Lamour. and the usual deep-water red algae [e.g. Phyco­ than around Langanes. A gradual increase of the width of drys rubens (L.) Batters, Delesseria sanguinea (Huds.) this high-level belt is a characteristic feature of the east Lam., Ptilota plumosa (L.) C. Ag., P. serrata Kiitz., Callo­ Icelandic vegetation type. Devaleraea ramentacea was belt­ phyllis cristata (C. Ag.) Kiitz., Fimbrifolium dichotomum forming in the lower eulittoral and the same was true for (Lepech.) Gobi, Odonthalia dentata (L.) Lyngb., Poly­ Acrosiphonia species. Chordaria flagellifo rmis was abun­ siphonia arctica J. Ag., P. urceolata (Lightf.) Grev. (on dant on exposed rocks in the outer regions of the fj ord, stipes of Laminaria hyperborea) and Rhodomela occurring in the lowermost eulittoral viz. the eulittoral/ lycopodioides]. sublittoral junction.

Mideast, central area Vopnafjordur In this area, situated further south, the vegetation was appar­ Mj 6ifjordur, Reydarfjordur, Faskrudsfjordur, ently even more influenced by cold-water masses, although Stodvarfjordur and Berufjordur average yearly temperatures from previous years (Stefansson The influence of the cold East Icelandic Current is strongest 1969, Table 1) as well as my own measurements (Table 1) in the mideast (Stefansson 1962, 1972, Malmberg & indicated slightly higher surface water temperatures than Stefansson 1972). The vegetation of several fj ords was around Langanes. In this open fj ord, the residual Atlantic studied and that ofReydarfjordur described in detail (Munda vegetation features were less pronounced than around the 1983). In the same fj ord, Adey (1968) studied deep water peninsula of Langanes. This was especially obvious in the crustose corallines. tide-pool vegetation. Cystoclonium purpureum was not A general characteristic feature of the east Icelandic found, and Ceramium spp. and Corallina of ficinalis were vegetation type was the absence of typical Atlantic floristic rather rare in the pools. The typical subarctic association of elements and their associations, the predominance of the Coilodesme bulligera-Ralfs ia fungiformis was even more brown algal component in the vegetation and the mixture of abundant than around Langanes. Moreover, filamentous several arctic and subarctic species in the vegetation such as brown algae predominated in most of the pools: Stictyo­ Laminaria nigripes J. Ag., Pantoneura baerii (Post. et siphon tortilis (Rupr.) Reinke in the upper eulittoral pools, Rupr.) Kylin, Polysiphonia arctica, Enteromorpha

Acta Phytogeogr. Suec. 78 Benthic algal vegetation 137

Table 2. Some characteri tic profile , common to the outer regions of the midea tern fj ords. There is a reduction in the number of eulittoral belt both on teep lopes and under strong wave exposure.

Level Steep slopes Moderate slope

Extreme exposure

High eulittoral Ulothrix pp.-Urospora penicilliformis Ulothrix spp.-Urospora penicilliformis Acrosiphonia spp.

Low eulittoraJ Ulothrix spp.-Urospora penicillifo rmis Acrosiphonia pp. (Po1phyra thulaea) Acrosiphonia arcta-Enteromorpha groenlandica Chordaria jlagelliformis Devaleraea ramentacea (broad belt)

Upper sublittoral Alaria esculenta A/aria esculenta

High exposure

High eulittoral Ulothrix spp.-Urospora spp. Porphyra umbilicalis Ulothrix pp.-Urospora pp. Blidingia spp.

Low eulittoral Acrosiphonia arcta Fucus distichus ssp.anceps Palmaria palmata Acrosiphonia spp. (or Porphyra thulaea) Deva/eraea ramentacea

Upper sublittoral Alaria esculenta A/aria esculenta

Medium exposure High eulittoral Bangia atropurpurea Porphyra umbilicalis Po1phyra umbilicalis Ulothrix spp.-Urospora pp. Ulothrix pp.-Urospora spp. Blidingia spp.-Petalonia iliform is f (mixed belt)

Low eulittoral Fucus distichus spp. anceps Fucus distichus spp. anceps Acrosiphonia arcta Acrosiphonia pp. (broad belt) Porphyra thulaea (or Devaleraea-Palmaria-Rhodomela) Devaleraea ramentacea (broad belt) f Chordaria ftagelliormis

Upper ublittoral A/aria esculenta A/aria esculenta

Fig. 6. Highly exposed site between Reydarfj ordur and Faskrudsfjordur, eastern Iceland, with A/aria esculenta, Acrosiphonia arcta and a wide belt of Ulothrix spp.-Urospora spp.

Acta Phytogeogr. Suec. 78 138 /.M. Munda

Iceland

• • Enteromorpha groenlandica • • Porphyra thulaea !::.. !::.. Laminaria nigripes --- Coilodesme bulligera o o Mastocarpus stellatus Fig. 7. Distribution of some X X Leathesia difformis Cystoclonium purpureum characteristic species along >> Corallina o.fftcinalis - Ceramium spp. the east coast of Iceland.

groenlandica (J. Ag.) Setch. et Gardn., Coilodesme bulligera, The main characteristics of the area were the extensive Tu rnerella pennyi (Harv.) Schm., Porphyra miniata Acrosiphonia meadows in the lower eulittoral on moderate (C. Ag.) C. Ag. var. amplissima Kj ellm., Porphyra thulaea rocky slopes below the fucoid settlements (Fig. 4), domi­

Munda et Pedersen and Monostroma arcticum Wittr. nated by A. arcta (Dillw.) J. Ag. and A. grandis Kj ellm. At In the mideast, theeulittoral belt of Ulothrix spp.-Urospora many sites the belts were fringed by the eo-dominant penicilliformis was broad and outstanding (Fig. 6). Occa­ Enteromorpha groenlandica, and where the exposure was sionally, on steep slopes with extreme surf, the belt was moderate Pilayella littoralis was a eo-dominant. found throughout the entire eulittoral zone, down to the Differences from the Atlantic water region of the Icelan­ sublittoral belt of A/aria esculenta (Fig. 5). The Porphyra dic coast were also found in the under torey of the fucoids, umbilicalis belt wa , on the other hand, less prolific than where Ralfsiafungiformis and the cru tose coralline Clathro­ along the north coast. Typical high-level associations of the morphum circumscriptum (Stromf.) Foslie were outstand­ east coast (cf. Table 2) were those of Acrosiphonia sonderi ing. In comparison with the fucoid associations in the (Kiitz.) Kornm., on moderately sloping rocky surfaces, of northwe tern fj ords (Munda 1 978a) there were no records in Blidingia specie [B. minima (Nag. ex Kiitz.) Kylin, the mideast of Plumaria elegans (Bonnem.) Schmitz, B. chadefaudii (Feldm.) Eliding, B. marginata (C. Ag.) Membranoptera alata (Huds.) Stackh.,Ceramium are­ Dang.] and of eo-dominant dwarf forms of Pilayella littoralis, schougii Kylin, C. rubrum (Huds.) C. Ag., Cladophora Spongomorpha aeruginosa (L.) Hoek, and Petalonia rupestris (L.) Kiitz., Phymatolithon lenormandii (Aresch.) .filiformis (Batters) Kuntze. Also dwarf-formed Scytosiphon Adey, P. polymorphum (L.) Foslie or Cystoclonium lomentaria was common within this high-level association purpureum. along with Rosenvingiella polyrhiza (Rosenv.) Silva and In the lower eulittoral broad and prolific belts of Isthmoplea sphaerophora (Harv.) Kjellm. Devaleraea ramentacea usually occurred (Fig. 3) with a In exposed areas ofthe east coast Fucus distichus was the few accompanying species such as Rhodomela lyco­ dominant fucoid. F. distichus ssp. edentatus and F. distichus. podioides, Palmariapalmata, Chordariaflagelliformis. The ssp. anceps could even follow each other throughout the D. ramentacea belts are a vegetation feature shared with the eulittoral, viz. the former dominating on vertical and more north coast, but there these belts are discontinuous and exposed slopes and the latter on moderate slopes of the same mixed with Atlantic floristic elements. transect. In the outermost exposed regions F. distichus ssp. On boulders and steep exposed rocks in the area between anceps occurred in narrow belts and in extremely reduced Mj6ifjordur and Berufjordur low eulittoral belts of Porphyra growth forms, whereas at extreme exposure, fucoids were thulaea were common (see Munda 1991, Fig. 5.12). At absent. Both F. vesiculas us and Ascophyllum nodosum were extreme wave exposure Chordariaflagellifo rmis was belt­ subordinate in the vegetation of the outer regions of the forming, its dense mats being mixed with Chorda tomentosa eastern fj ords, while F. spiralis was limited to the fj ords Lyngb., and usually interposed between the belts of Por­ proper. phyra thulaea and A/aria esculenta.

Acta Phytogeogr. Suec. 78 Benthic algal vegetation 139

The upper sublittora1 was occupied by narrow Alaria The benthic algal vegetation of the mideastem fj ords esculenta (Fig. 5) with several companion specie as Mj6ifjordur, Reydarfjordur, Faskrudsfjordur and Stbdvar­ understorey such as Rhodomela lycopodioides, Palmaria fj ordur was similar and the same was true for shores of the palmata, Chordaria flagelliformis, Chorda tomentosa, island of Seley and Papey. Minor vegetational differences Polysiphonia arctica and Ralfsiafungiformis, R. verrucosa were obvious between inner and middle areas of these (Aresch.) J. Ag., Sphacelaria radicans (Dillw.) J. Ag., fj ords. Audouinella purpurea (Lightf.) Woelk., Polysiphonia A predominance of Petalonia species (P. zosterifolia, urceolata and crustose corallines (e.g. Clathromorphum P. fa scia) was characteristic of Mj6ifjordur, whereas in circumscriptum, Lithothamnion spp., L. glaciale Kj ellm.). Stodvarfjordur the Coilodesme bulligera-Ralfs iafungiformis The characteristic algal as ociations found in different association extended far into the fj ord proper. In Berufjordur, vertical sequences, dependent on the inclination of the rocks situated further south, the influence of arctic water masses and on exposure conditions, are shown in Table 2. Under on the benthic algal vegetation declined. Coilodesme extreme expo ure condition a wide belt of Ulothrix spp.­ bulligera was rather rare in this fj ord and low eulittoral belts U rospora penicillifo rmis occupied the entire eulittoral slopes, of Porphyra thulaea and Enteromorpha groenlandica were down to the sublittoral Alaria esculenta zone with some found only along its northern banks, between Nupur and Acrosiphonia arcta interposed (Fig. 6). Table 2 shows that Straeti. Along the southern banks, some Atlantic tide-pool Palmaria palmata, Porphyra thulaea and Chordaria assoc1atwn were observed (Ceramium rubrum and flagellifo rmis prefer steep slopes, whereas belts of Acro­ Dumontia contorta). Single specimens of Corallina siphonia species and Devaleraea ramentacea were more offi cinalis occurred in the vegetation both in the tide pools common on moderately sloping rocky surfaces. However, and attached to the haptera of Laminaria hyperborea. The the sequence of the main algal belts varied from place to high-level Ulothrix spp.-Urospora spp. belts were still broad place. Reduced algal belts were evident at high wave expo­ and outstanding, especially at heavily exposed sites. How­ sure, which eliminated both the fucoids and the Porphyra ever, in general the benthic algal vegetation of Berufjordur umbilicalis belts. The low eulittoral association of Palmaria still exhibited the same subarctic character as the rest of the palmata, was found occasionally on teep slopes, as is also mideastem fj ords. the case on the island of Grfmsey (Munda 1977). Tide-pool associations, typical of the east coast were those of Coilodesme bulligera-Rafl sia fu ngiformis, Southeastern area Acrosiphonia spp., Devaleraea ramentacea and diverse filamentous brown algae. In the upper pools Stictyosiphon Eystrahorn (Hvalnes) and Vestrahorn (Stokksnes) tortilis and Petalonia fa scia were abundant, while in the The outer promontories between Alftafjordur, L6nsfjordur lower Chordaria flagelliformis and Dictyosiphon fo enicu­ and Hornafjordur are in contact with oceanic water and laceus (Huds.) Grev. dominated. Eudesme virescens and their vegetation reflects the hydrographic conditions in this S. lomentaria were found in between other filamentous particular area. A sharp floristic and vegetational change algae and did not form separate associations. At the time of was fo und on the line between Hornafjordur and my observations Monostroma species (M. undulatum Wittr., Hrollaugseyjar. It is likely, however, that the position of the M. arcticum) were common tide-pool inhabitants in the border between the typically Atlantic and the subarctic outer fj ord regions. Due to lack of competition with diverse vegetation reflects several years of translocations of the Atlantic tide-pool associations, Fucus distichus ssp. distichus frontal zone and the southwards extension of a tongue of Powell was frequent in tide pools of different eulittoral cold water, which could reach as far south as to Ingolfshofdi levels, whereas it was rather rare in the Atlantic water (Stefansson 1972, Malmberg & Stefansson 1972). regions of Iceland. A morphocline of the dominant species The benthic algal vegetation was studied on both sides of and a gradient in floristic composition and physiognomy of the frontal zone viz. Eystrahom (surroundings ofHvalnes to the association was observed from the upper towards the Mellifelsdalur) north and Vestrahom (Stokksnes to Hafnar­ lower pools (cf. Munda 1981, 1983, 1991). nes) south of the front. On both sides of the frontal zone the Coastal lagoons were most often populated by Saccorhiza vegetation of extremely exposed sites was similar, with dermatodea. On the other hand, Laminaria digitata and extremely reduced algal belts. The entire eulittoral slopes L. saccharina were limited to some lagoons in the fj ords were populated by a belt of Ulothrix spp.-Urospora proper. The arctic species Laminaria nigripes was found in penicilliformis, reaching down to the sublittoral Alaria rather small amounts in the mideastem fj ords. The upper esculenta belt. Some specimens of Acrosiphonia arcta were sublittoral was occupied continuously by Alaria esculenta, found in rocky fissures. This vegetation might also repre­ while in the lower sub littoral forests ofLaminaria hy perborea sent the first regrowth after the ice scouring, since my were dense and prolific, as was obvious also from the drift observations were carried out during the years with severe weed. The red algae Pantoneura baerii, Phyllophora truncata ice conditions. It was, however, also similar to the vegeta­ (Pallas) Newroth and Porphyra miniata var. amplissima tion found at extreme wave exposure in the mideast (cf. Fig. joined the sublittoral vegetation. 6).

Acta Phytogeogr. Suec. 78 140 /.M. Munda

At sheltered sites around Hvalnes north of the front, a inconspicuous, since Pelvetia canaliculata (L.) Decne et more varied eulittoral vegetation was found. In general, the Thur. occupied this level. Belts of Mastocarpus stellatus, vegetation was still similar to that observed in the mideast, Callithamnion sepositum, Corallina officina/is were found with belts of Devaleraea ramentacea, Chordaria flagel­ in the lower eulittoral, while the tide pools were occupied liformis, Palmaria palmata and extensive meadows of by the latter species as well as by Ceramium spp., Cystoclo­ Acrosiphonia spp., along with tide-pool associations of the nium purpureum, Dumontia contorta, Ahnfe ltia plicata same species. However, several subarctic features were no and Chondrus crispus Stackh. In this area Membranoptera longer characteristic of the tide pools and eulittoral slopes. alata, Plumaria elegans, Phymatolithon lenormandii and Ralfsiafungiformis was rare, and associations of such spe­ P. polymorphum appeared again in the understorey of cies as Coilodesme bulligera, Monostroma arcticum, Por­ the fucoids and Laminaria digitata f. stenophylla was found phyra thulaea and Enteromorpha groenlandica, were lack­ in the upper sublittoral. ing. Laminaria nigripes, Pantoneura baerii, Turnerella pennyi, Polysiphonia arctica did not occur in the sub littoral. Atlantic floristic elements and associations found in the outer area of Berufjordur further north were absent along Conclusions this coastline. However, a record of the Atlantic species Ahnfe ltia plicata (Huds.) Fries outside Alftafjordur is note­ The benthic algal vegetation of eastern Iceland showed a worthy. sharp contrast to that of other areas of the Icelandic coast. Hornafjordur is situated on the southern side of the nor­ The changes were quite clearly related to hydrographic mal hydrographic boundary area. Hence the usual Atlantic conditions along this coastline, viz. a gradual mixing and vegetation pattern had been expected. However, the benthic vegetation-transition in the northeast, maximum influence algal vegetation of Stokksnes and Hafnames was similar to of cold water masses in the mideast and a sharp floristic and that observed at exposed sites around Hvalnes as well as to vegetation limit in the southeast, which coincided with that in the mideast. Narrow belts of Porphyra umbilicalis translocations of the frontal zone. The distribution of some were locally found above the belts of Vlothrix spp.-V rospora characteristic species along the east coast is presented in spp. with Acrosiphonia arcta at their lower edges. Fig. 7. The algal zonation of semi-exposed sites off Hornafjordur The strongest influence of cold water masses on the was similar to that found in the mideast viz. belts of Porphyra benthic algal vegetation was obvious in the mideast, be­ umbilicalis-Vlothrix spp.-Vrospora spp.-A udouinella tween Seydisfjordur and Berufjordur. It was manifested in: purpurea (occasional1y interposed)-Fucus distichus ssp. (1) the increased width of the Vlothrix spp.-Vrospora anceps-Ac rosiphonia arcta-Devale raea ramentacea-A laria penicilliformis belt; (2) the occurrence of low eulittoral esculenta. Besides the subarctic species, absent already belts of Devaleraea ramentacea, Chordaria flagelliormisf around Eystrahom, also Ralfsia fungiformis was lacking with Chorda tomentosa, Porphyra thulaea, Enteromorpha around Vestrahom. groenlandica with Acrosiphonia arcta, and wide meadows In the extreme southeast, on both sides of the frontal zone, of several Acrosiphonia species; (3) the mixture of several there are landlocked fj ords with soft substrata, reduced tidal subarctic and arctic species (e.g. Pantoneura baerii, movements and an estuarine vegetation. Opportunistic brown Laminaria nigripes and Porphyra miniata var. amplissima) and green algae predominated in these fj ords (e.g. Entero­ in the sublittoral vegetation; ( 4) the absence of typical morpha spp., Cladophora spp., Ectocarpus spp., Dictyo­ Atlantic species and their associations. siphon spp., Vlva lactuca, Capsosiphonfulvescens (C. Ag.) The influence of cold water masses was expected to Setch. et Gardn. Chorda filum, Stictyosiphon tortilis and decline already along the southern banks of Berufjordur, but Pilayella littoralis). In the wide Hornafjordur, where soft the vegetation there still showed subarctic features. The substrata prevail, fucoids were found in patches [Fucus southeastern open coast, with highly exposed promontories spiralis, F. vesiculosus, Ascophyllum nodosum, F. distichus around Vestrahom, still shared vegetation features with the ssp. evanescens (C. Ag.) Powell] along with Acrosiphonia mideast, though with some floristic changes. Typical sub­ spp., Enteromorpha spp., Palmaria palmata, and Viva arctic species no longer occurred, but the main associations lactuca. A find of the Atlantic species Ceramium rub rum is of the low eulittoral and tide pools were still present. noteworthy. The floristic and vegetational shift towards the typical The greater part of the south coast of Iceland consists of Atlantic vegetation of the southern coast was translocated to sandy substrate, devoid of algal vegetation. Further obser­ the area between Homafjordur and the island of Hrol­ vations of algae were possible only on the small island of laugseyjar. This limit most likely reflects several years of Hrollaugseyjar, situated further south and west (64° N, 16° displacements of the frontal zone. W). On this island the vegetation was already typically In contrast to the sharp floristic and vegetational limit warm boreal, with all the floristic elements and associations found in the southeast, a gradual transition between the characteristic of the south coast. The high-level eulittoral north and east Icelandic vegetation types was found in the belt of Vlothrix spp.-Vrospora spp. was again narrow and hydrogra phic mixing area in the northeast. A gradual disap-

Acta Phytogeogr. Suec. 78 Benthic algal vegetation 141

pearance of Ceramium spp., Mastocarpus stellatus, Reun. Cons. Int. Explor. Mer 162: 185-200. Cystoclonium purpureum, Dumontia contorta, Phymato­ Munda, I.M. 1972. General fe atures of benthic algal zonation lithon spp., Corallina officinalis, Leathesia difformis was around the Icelandic coast.- Acta Nat. Isl. 21: 1-34. characteristic of thjs hydrographic mixing area. Melrakka­ Munda, I.M. 1975. Hydrographically conditioned floristic and vegetation limits in Icelandic coastal waters.- Bot. Mar. 18: sletta represented a typical transitional area similar to the 223-235. north coast, while the peninsula of Langanes was under Munda, I.M. 1977. The benthic algal vegetation of the island of intensified influence of cold water masses and also drift ice. Grimsey (Eyjafjardarsysla, North Iceland). - Res. Inst. Nedri Here the subarctic species Coilodesme bulligera joined the As, Hveragerdi, Iceland. Bull. 28: 1-69. vegetation in notable amounts. Some Atlantic water species Munda, I.M. 1978a. Survey of the benthic algal vegetation of the disappeared and others became subordinate in the vegetation. Dyrafjordur, Northwest Iceland. - Nova Hedwigia 29: 281- The extreme variations of floristic and vegetation limits 403. within the eastern Icelandic waters thus widely surpass Munda, I.M. 1978b. Salinity dependent distribution of benthic those found in other areas of the north Atlantic Ocean, e.g. algae in estuarine areas of Icelandic fj ords. - Bot. Mar. 21: 45 1 -486. the Faeroes (Borgesen 1902, 1905, Price and Farnharn Munda, I.M. 1980. Survey of the benthic algal vegetation of the 1982, Tittley et al. 1982), northern Norway (Jaasund 1965) Borgarfjordur, Southwest Iceland. - Nova Hedwigia 32: 855- and the Shetlands (lrvine 1974). 927. Munda, I.M. 1981. Tide pool associations of benthic algae in Icelandic waters. - In: Levring, T. (ed.) Proc. lOth Int. Seaweed Symp. Goteborg, Sweden, August 11-15, 1980. pp. 327-332. Waiter de Gruyter, Berlin. References Munda, I.M. 1983. Survey of the benthic algal vegetation of the Reydarfjordur, as a typical example of the East Icelandic Adey, W .H. 1968. The distribution of crusto se corallines on the vegetation pattern. - Nova Hedwigia 37: 545-640. Icelandic coast. -Soc. Sci. Islandica 1: 1-31. Munda, I. M. 1987. Characteristic features of the benthic algal Borgesen, F. 1 902. Marine algae.-In: Warming, E.I. (ed.) Botany vegetation of the Snaefellsnes peninsula (Southwest Iceland). of the Faeroes based on Danish investigations. Part 2. pp. 339- - Nova Hedwigia 44: 395-448. 532. Det Nordiske Forlag, Copenhagen. Munda, I.M. 1991. Shoreline ecology in Iceland, with special Borgesen, F. 1905. The algae-vegetation of the Faeroese coasts emphasis on the benthic algal vegetation - In: Mathieson, with remarks on the phyto-geography. - In: Warming, E.I. A.C. & Nienhuis, P.H. (eds.) Ecosystems of the World 24. (ed.) Botany of the Faeroes based on Danish investigations. Intertidal and littoral. ecosystems. pp. 67-8 1 . Else vier, Amster­ Part 3. pp. 683-834. Det Nordiske Forlag, Copenhagen. dam. Einarsson, T. 1969. The ice in the North Polar Basin and the Price, J.H. & Farnham, W.F. 1982. Seaweeds of the Faeroes. 3. Greenland Sea and the general causes of occasional approach Open shores. - Bull. Br. Mus. Nat. Hist. 10: 153-225. of ice to the coast of Iceland. - Jokull 19: 2-6. Sigtryggsson, H. 1972. An outline of sea-ice conditions in the Irvine, D.E.G. 1974. The marine vegetation of the Shetland Isles. vicinity of Iceland. - Jokull 22: 1-11. - In: Goodier, R. (ed.) The natural environment of the Shet­ Stefansson, U. 1962. North Icelandic waters. - Rit Fiskideildar 3: land Isles. pp. 107- 1 13. Edinburgh. 1-269. Jaasund, E. 1965. Aspects of the benthic algal vegetation of Nmth Stefansson, U. 1969. Sjavarhiti a siglingaleid umhverfis Island. Norway. - Bot. Gothoburgensia 4: 1-174. Hafisinn. Almenna B6kafelagid, Reykjavik. pp. 131-149. J6nsson, H. 1910. Om algevegetationen ved Islands kyster. - Bot. Stefansson, U. 1972. Near-shore fluctuations of the frontal zone Tidskr. 30: 223-328. southeast of Iceland. - Rapp. p.v.-Reun. Cons. Int. Explor. J6nsson, H. 1912. The marine algal vegetation. - In: Rosenvinge, Mer 162: 201 -205. K.L. & Warming, E.I. (eds.) The Botany of Iceland. pp. 1-186. Stromfelt, H.F.G. 1 886. Om algvegetationen vid Islands kuster. ­ I.Y. Frimodt, Copenhagen. Diss. Bonniers, Goteborg. 89 pp. Lamb, H.H. 1979. Climatic variations and changes in the wind and Tittley, I., Famham, W.F. & Gray, P.W.G. 1982. Seaweeds of the ocean circulation. The little ice age in the northeast Atlantic. ­ Faeroes. 2. Sheltered fj ords and sounds. - Bull. Br. Mus. Nat. Quart. Res. 11: 1-20. Hist. 10: 133-151. Malmberg, S.A. 1969. Hydrographic changes in the waters be­ tween Iceland and Jan Mayen in the last decade. - Jokull 19: 30-43. Malmberg, S, A. 1972. Annual and seasonal variations in the East Icelandic Current between Iceland and Jan Mayen. - In: Karlsson, T. (ed.) Sea Ice. Proc. Int. Conf. Reykjavik. National Research Council 4: 42-54. Malmberg, S.A. l984. Hydrographicconditions in the East Icelan­ dic Current and sea ice in the North Icelandic waters, 1970- 1980. - Rapp. p.v.-Reun. Cons. Int. Explor. Mer 185: 170- 178. Malmberg, S.A. & Stefansson, U. 1972. Recent changes in the water masses of the East Icelandic Current. - Rapp. p.v.-

Acta Phytogeogr. Suec. 78 SVENSKA V AXTGEOGRAFISKA SALLSKAPET SOCIETAS PHYTOGEOGRAPHICA SUECANA Address: Vaxtbiologiska Institutionen, Box 559, S-75 1 22 Uppsala, Sweden

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ACTA PHYTOGEOGRAPHICA SUECICA

1. E. Almquist, Upplands vegetation och flora. (Vegetation and 12. G. E. Du Rietz, A. G. Hannerz, G. Lohammar, R. Santesson flora of Uppland.) 1929. ISBN 91-72 10-001-X. & M. Wcern, Zur Kenntnis der Vegetation des Sees Takern. 2. S. Th unmark, Der See Fiolen und eine Vegetation. 1931. 1939. 120:-. ISBN 91-72 10-01 2-5. 200:-. ISBN 91-7210-002-8. 13. Vaxtgeografiska studier tillagnade Car! Skott berg pa extio­ 3. G. E. Du Rietz, Life-form of terre trial flowering plants. I. arsdagen 1/12 1940. (Geobotanical studies dedicated to C. 1931. 120:-. ISBN 91-721 0-003-6. Skottsberg.) 1940. 240:-. ISBN 91-7210-01 3-3. 4. B. Lindquist, Om den vildvaxande kog a1men raser och 14. N. Hylander, De ven ka formerna av Mentha gentili L. deras utbredning i Nordva teuropa. (Summary: The races of coli. (Zu ammenf. : Die chwedischen Formen der Mentha spontaneous Ulmus glabra Huds. and their distribution in gentilis L. sen u coli.) 1941. 120:-. ISBN 91-72 10-014-l. NEW. Europe.) 1932. ISBN 91-72 1 0-004-4. 15. T. E. Hasselrot, Till kannedom om nagra nordiska umbi­ 5. H. Osvald, Vegetation of the Pacific coast bogs of North licariaceers utbredning. (Zusammenf. : Zur Kenntnis der America. 1933. 120:-. ISBN 91-721 0-005-2. Verbreitung einiger Umbilicariaceen in Fennoscandia.) 1941. 6. G. Samuelsson, Die Verbreitung der hoheren Wasserpflanzen 120:-. ISBN 91-72 10-01 5-X. in Nordeuropa. 1934. ISBN 91-72 1 0-006-0. 16. G. Samuelsson, Die Verbreitung der Alchemilla-Arten aus 7. G. Degelius, Das ozeanische Element der Strauch und Laub­ der Vulgaris-Gruppe in Nordeuropa. 1943. 120:-. ISBN 91- flechtenflora von Skandinavien. 1935. ISBN 91-72 1 0-007- 72 10-0 16-8. 9. 17. Th. Arwidsson, Studien uber die Gefasspflanzen in den 8. R. Sernander, Granskar och Fiby urskog. En studie over Hochgebirgen der Pite Lappmark. 1943. 200:-. ISBN 91- stormluckornas och marbuskarnas betydel e i den svenska 7210-01 7-6. granskogens regeneration. (Summary: The primitive forests 18. N. Dahlbeck, Strandwiesen am udostlichen Oresund. of Granskar and Fiby. A study of the part played by storm­ (Summary: Salt marshes on the S. E. coastofbre und.) 1945. gaps and dwarf trees in the regeneration of the Swedish 120:-. ISBN 91-7210-0 1 8-4. pruce forest.) 1936. 200:-. ISBN 91-72 10-008-7. 19. E. von Krustenstjerna, Bladmossvegetation och blad­ 9. R. Sterner, Flora der Insel bland. Die Areale der Gefarss­ mossflora i Uppsa1atrakten. (Summary: Moss flora and moss pflanzen Glands nebst Bemerkungen zu ihrer Oekologie und vegetation in the neighbourhood of Uppsala.) 1945. 240:-. Soziologie. 1938. ISBN 91-721 0-009-5. ISBN 91-72 10-01 9-2. 10. B. Lindquist, Dalby Soderskog. En skansk lOvskog i forntid 20. N. Albertson, bsterplana hed. Ett alvarornrade pa Kinne­ och nutid. (Zusammenf.: Ein Laubwald in Schonen in der kulla. (Zusammenf. : bsterplana hed. Ein Alvargebiet auf Vergangenheit und Gegenwart.) 1938.200:-. ISBN 91-7210- dem Kinnekulle.) 1946. 200:-. ISBN 91 -72 1 0-020-6. 010-9. 21. H. Sj ors, Myrvegetation i Bergslagen. (Summary: Mire ve­ 11. N. Stalberg, Lake Vattern. Outlines of its natural hi tory, getation in Bergslagen, Sweden.) 1948. 240:-. ISBN 91- especially its vegetation. 1939. 120:-. ISBN 91-7210-01 1-7. 7210-02 1-4.

Acta phytogeogr. suec. 78 Svenska Vaxtgeografiska Sallskapet 143

22. S. Ahlner, Utbredningstyper bland nordiska barrtradslavar. och vegetation. (Resume: Dynamik und Konstanz in der (Zusammenf. : Yerbreitung typen unter fe nnoskandischen N Flora und Vegetation von Gotland, Schweden.) 1958. 320:­ adelbaumflechten. ) 1948. 200:-. ISBN 91-72 1 0-022-2. . ISBN 91-721 0-040-0. 23. E. Julin, Vessers udde, Mark och vegetation i en igenvaxande 41. E. Uggla, Skogsbrandfalt i Muddus national park. (Summary: !Ovang vid Bjarka-Saby. (Zusammenf. : Vessers udde. Boden Forest fire areas in Muddu National Park, Northern Sweden.) u nd Vegetation in ei ner verwach en den Laubwie e bei Bj arka­ 1958. 120:-. ISBN 91-72 10-041-9. Saby in bstergotland, Stidschweden.) 1948. 200:-. ISBN 91- 42. K. Th omasson, Nahuel Huapi. Plankton of some lakes in an 72 1 0-023-0. Argentina National Park, with note on terrestrial vegetation. 24. M. Fries, Den nordi ka utbredningen av Lactuca a1pina, 1959. 120:-. ISBN 91 -721 0-042-7. Aconitum eptentrionale, Ranunculus platanifoliu och 43. V. Gillner, Vegetations- und Standortsuntersuchungen in Polygonatum verticillatum. (Zusammenf. : Die nordische den Strandwiesen der schwedi chen Westktiste. 1960. 200:­ Verbreitung von Lactuca alpina.) 1949. 120:-. ISBN 91- ISBN 91-72 10-043-5. 72 1 0-24-9. 44. E. Sj ogren, Epiphytische Moosvegetation in Laubwaldern b 25. 0. Gjcerevoll, Sn!Z!leievegetasjonen i Oviksfjellene. der Insel land, Schweden. (Summary: Epiphytic moss (Summary: The snow-bed vegetation of Mt Oviksfjallen, communitie in deciduous woods on the island of bland, Himtland, Sweden.) 1949. 120:-. ISBN 91-72 1 0-025-7. Sweden.) 1961. 120:-. ISBN 917210-044-3 (ISBN 91-72 10- 26. H. Osvald, Note on the vegetation of British and Irish 444-9). mo e.19 49. 120:-. ISBN 91-72 10-026-5. 45. G. Wistrand, Studier i Pite Lappmarks karlvaxtflora, med 27. S. Selander, Flori tic phytogeography of SouthWestern Lule sarskild hansyn till kog landet och de isolerade fj allen. Lappmark (Swedi h Lapland). I. 1950. 200:-. ISBN 91- (Zu ammenf. : Studien uber die Gefasspflanzenflora der Pite 72 1 0-027-3. Lappmark mit besonderer Berticksichtigung des Waldlandes 28. S. Selander, Flori tic phytogeography of SouthWestern Lule und der isolierten niederen Fj elde.) 1962. 200:-. ISBN 91- Lappmark (Swedish Lapland). II. Karlvaxtfloran i sydvastra 7210-045- 1 (ISBN 91-72 1 0-445-7). Lule Lappmark. (Summary: Vascular flora.) 1950. 120:-. 46. R. lvarsson, Lovvegetation i Mollosunds socken. (Zu­ ISBN 91-7210-028- I. ammenf.: Die Laubvegetation im Kirchspiel Mollo und, 29. M. Fries, Pollenanalytiska vittnesbord om senkvartar Bohuslan, Schweden.) 1962. 120:-. ISBN 91-72 1 0-046-X vegetation utveckling, sarskHt skogshi toria, i nordva tra (ISBN 91-72 1 0-446-5). Gotaland. (Zusammenf.: Pollenanalyti che Zeugni se der 47. K. Th omasson, Araucanian Lakes. Plankton studie in North patquartaren Vegetation entwicklung, hauptsachlich der Patagonia, with note on terre trial vegetation. 1963. 200:-. Waldgeschichte, im nordwestlichen Gotaland, Stidschweden.) ISBN 91-72 10-047-8. 1951. 200:-. ISBN 91-721 0-029-X. 48. E. Sj ogren, Epiliti che und epigai che Moosvegetation in 30. M. Wcern,Rocky-sh ore algae in the bregrund Archipelago. Laubwaldern der Insel bland, Schweden. (Summary: Epilithic 1952. 240:-. ISBN 91-7210-030-3. and epigeic moss vegetation in deciduou woods on the b 31. 0. Rune, Plant life on serpentine and related rock in the i land of land, Sweden.) 1964. 200:-. ISBN 91-721 0-048- North of Sweden. 1953. 120:-. ISBN 91-72 10-031-1. 6 (ISBN 91-72 10-448- 1 ). 32. P. Kaaret, Was ervegetation der Seen OrHingen und 49. 0. Hedberg, Features of afroalpine plant ecology. (Re ume Trehorningen. 1953. 120:-. ISBN 91-72 10-032-X. fran9ai .) 1964. 200:-. ISBN 9 1-72 10-049-4 (ISBN 91-72 10- 33. T. E. Hasselrot, Nordliga lavar i Syd- och Mellansverige. 449-X). (Nordliche Flechten in SUd- und Mittel chweden.) 1953. 50. The PJant CoverofSweden. A study dedicated to G. Einar Du 200:-. ISBN 91-72 10-033-8. Rietz on hi 70th birthday by his pupils. 1965. 400:-. ISBN 34. H. Sj ors, SUitterangar i Grangarde fi nnmark. (Summary: 91-72 I 0-050-8. Meadows in Grangarde Finnmark, SW. Dalarna, Sweden.) 51. T. Flensburg, Desmids and other benthic algae of Lake 1954. 120:-. ISBN 91-72 1 0-034-6. Kavsjon and Store Mos e. SW Sweden. 1967. 200:-. ISBN 35. S. Kilander, Karlvaxternas ovre granser pa fj all i sydvastra 91-72 10-05 1-6 (ISBN 91-72 10-451-1). Jamtland samt angran ande delar av Harjedalenoch Norge. 52. E. Skye, Lichens and air pollution. A tudy of cryptogamic (Summary: Upper limits ot vascular plants on mountains in epiphytes and environment in the Stockholm region. 1968. Southwestern Jamtland and adjacent parts of Harjedalen 200:-. ISBN 91-72 10-052-4 (ISBN 91-72 10-452-X). (Sweden) and Norway.) 1955. 200:-. ISBN 91-72 10-035 -4. 53. Jim Lundqvist, Plant cover and environment of steep hill ides 36. N. Quennerstedt, Diatomeerna i Uingans sjovegetation. in Pi te Lappmark. (Resume: La cou verture vegetale et l' habitat (Summary: Diatoms in the lake vegetation ot the Langan des flancs escarpes de collines de Pite Lappmark.) 1968. drainage area, Jamtland, Sweden.) 1955. 200:-. ISBN 91- 200:-. ISBN 91-72 10-053-2 (ISBN 91-72 10-453-8). 72 1 0-036-2. 54. Conservation of Vegetation in Africa South of the Sahara. 37. M. -B. Florin, Plankton of fresh and brackish waters in the Proc. of symp. at 6th plen. meeting of AETFA T. Ed. by Inga Sodertalje area. 1957. 120:-. ISBN 91-72 10-037-0. and Olov Hedberg. 1968. 240:-. ISBN 91-72 10-054-0 (ISBN 38. M. -B. Florin, Insjostudier i Mellansverige. Mikrovegetation 91-721 0-454-6). och pollenregn i vikar av bstersjobackenet och insjoar fran 55. L.-K. Konigsson, The Holocene history of the Great Alvar of preboreal tid till nutid. (Summary: Lake tudies in Central bland. 1968. 240:-. ISBN 91-721 0-055-9 (ISBN 91-7210- Sweden. Microvegetation and pollen rain in inlets of the 455-4). Baltic basin and in lakes from Preboreal time to the present 56. H. P. Hallberg, Vegetation auf den Schalenblagerungen in day.) 1957. 120:-. ISBN 91-72 10-038-9. Bohuslan, Schweden. (Summary: Vegetation on shell deposits 39. M. Fries, Vegetationsutveckling och odlingshistoria i in Bohuslan, Sweden.) 1971. 200:-. ISBN 91-72 10-056-7 Varnhemstrakten. En pollenanalytisk undersokning i Vas­ (ISBN 91-72 1 0-456-2). tergotland. (Zusammenf.: Vegetationsentwicklung und 57. S. Fransson, Myrvegetation i sydvastra Varrnland.(Su mmary: Siedlungsge chichte im Gebiet von Varnhem. Eine Mire vegetation in south-western Varm1and, Sweden.) 1972. pollenanalytische Untersuchung aus Vastergot1and (Stid­ 200:-. ISBN 91-7210-057-5 (ISBN 91-7210-457-0). schweden).) 1958. 120:-. ISBN 91-72 10-039-7. 58. G. Wa llin, Lovskog vegetation i Sj uharadsbygden. 40. Bengt Pettersson, Dynamik och konstan i Gotlands flora (Summary: Deciduous woodlands in Sj uharadsbygden, Vas-

Acta phytogeogr. suec. 78 144 Svenska Viixtgeografiska Siillskapet

tergotland, south-western Sweden.) 1973. 200:-. ISBN 91- STUDIES IN PLANT ECOLOGY 721 0-058-3 (ISBN 91-7210-458-9). (vols. 1-18 V AXTEKOLOGISKA STUDIER) 59. D. Johansson, Ecology of vascular epiphytes in West African rain forest. (Resume: Ecologie des epiphytes vasculaires 1. S. Brakenhielm & T. lngelog, Vegetationen i Kungshamn­ dans la foret dense humide d' Afrique occidentale.) 1974. Morga naturreservat med fOrslag till skotselplan. (Summary: 240:-. ISBN 91-7210059- 1 (ISBN 91-721 0-459-7). Vegetation and proposed management in the Kungshamn­ Morga Nature Reserve south of Uppsala.) 1972. 80:-. ISBN 60. N. Olsson, Studies on South Swedish sand vegetation. 1974. 200:-. ISBN 91-7210-060-5 (ISBN 91-721 0-460-0). 91-7210-801 -0. 2. T. lngelOv M. Risling, Kronparken vid Uppsala, historik 61. H. Hytteborn, Deciduous woodland at Andersby, Eastern & och bestfmdsanalys av en 300-arig tallskog. (Summary: Sweden. Above-ground tree and shrub production. 1975. Kronparken, history and analysis of a 300-year old pinewood 200:-. ISBN 91-7210-06 1-3 (ISBN 91-7210-46 1-9). near Uppsala, Sweden.) 1973. 80:-. ISBN 91-7210-802-9. 62. N. Persson, Deciduous woodland at Andersby, Eastern 3. H. Sj ors och medarb., Skyddsvarda myrar i Kopparbergs Jan. Sweden. Field-layer and below-ground production. 1975. (Summary: Mires considered for protection in Kopparberg 120:-. ISBN 91-721 0-062- 1 (ISBN 91-7210-462-7). County (Prov. Dalarna, Central Sweden).) 1973. 80:-. ISBN 63. S. Brakenhielm, Vegetation dynamics of afforested farmland 91-7210-803-7. in a district of South-eastern Sweden. 1977. 200:-. ISBN 91- 4. L. Karlsson, Autecology of cliff and scree plants in Sarek 721 0-063-X (ISBN 91-7210-463-5). National Park, northern Sweden 1973. 120:-. ISBN 91-7210- 64. M. Ammar, Vegetation and local environment on shore 804-5. ridges at Vickleby, bland, Sweden. An analysis. 1978. 200:­ 5. B. Klasvik, Computerized analysis of stream algae. 1974. . ISBN 91-721 0-064-8 (ISBN 91-7210-464-3). 80:-. ISBN 91-7210-805-3 . 65. L. Kullman, Change and stability in the altitude of the birch 6. Y. Dahlstrom-Ekbohm, Svensk miljovards- och omgivnings­ tree-limit in the southern Swedish Scandes 1915-1975. 1979. hygienlitteratur 1952-1 972. Bibliografi och analys. 1975. 200:-. ISBN 91-721 0-065-6 (ISBN 91-7210-465-1). 80:-. ISBN 91-7210-806- 1. 66. E. Waldemarsonlensen, Successions in relationship to lagoon 7. L. Rodenborg, Bodennutzung, Pflanzenwelt und ihre b development in the Laitaure delta, North Sweden. 1979. Veranderungen in einem alten Veidegebiet aufMittei- iand, 200:-. ISBN 91-7210-066-4 (ISBN 91-721 0-466-X). Sweden. 1976. 80:-. ISBN 91-7210-807-X. 67. S. Tuhkanen, Climatic parameters and indices in plant 8. H. Sj ors & Ch. Nilsson, Vattenutbyggnadens effekter pa levande natur. En faktaredovisning overvagande frfm geography. 1980. 200:-. ISBN91-721 0-067-2 (ISBN91.7210- Umealven. (Summary: Bioeffects of hydroelectric 467-8). development. A case study based mainly on observations 68. Studies in plant ecology dedicated to Hugo Sj ors. Ed. Erik along the Ume River, northern Sweden.) 1976. 120:-. ISBN Sjogren. 1980. 240:-. ISBN 91-721 0-068-0 (ISBN 91-7210- 91-7210-808-8. 468-6). 9. J. Lundqvist & G. Wistrand, Strandflora inom ovre och 69. C. Nilsson, Dynamics of the shore vegetation of a North mell�\sta Skelleftealvens vattensystem. Med en samman­ Swedish hydro-electric reservoir during a 5-year period. fattning betraffande botaniska skyddsvarden. (Summary: 1981. 200:-. ISBN 91-721 0-069-9 (ISBN 91-7210-469-4). Riversi�e vascular flora in the upper and middle catchment 70. K. Wa renberg, Reindeer forage plants in the early grazing area of e�e River Skelleftealven, northern Sweden.) 1976. season. Growth and nutritional content in relation to climatic 80:-. ISBN 91-7210-809-6. conditions. 1982. 200:-. ISBN 91-7210-070-2 (ISBN 91- 10. A. Miiller-Haeckel, Migrationsperiodik einzelliger Algen in 721 0-470-8). Fliessgewassern. 1976. 80:-. ISBN 91-7210-810-X. 71. C. Johansson, Attached algal vegetation in running waters of 11. A. Sj odin, Index to distribution maps of bryophytes 1887- Jamtland, Sweden. 1982. 200:-. ISBN 917210-07 1-0 (ISBN 1975. I. Musci. 1980. 120:- (hard-bound). ISBN 91-7210- 91-7210-471-6). 811-8. 72. E. Rosen, Vegetation development and sheep grazing in 12. A. Sj odin, Index to distribution maps of bryophytes 1887- limestone grasslands of south bland, Sweden. 1982. 240:-. 1975. 11. Hepaticae. 1980. 80:- (hardbound). ISBN 91-7210- ISBN 91-721 0-072-9 (ISBN 91-721 0-472-4). 812-6. 73. L. Zhang, Vegetation ecology and population biology of 13. 0. Eriksson, T. Palo & L. Soderstrom, Renbetning vintertid. Undersokningar rorande svensk tamrens naringsekologi un­ Fritillaria meleagris L. at the Kungsangen Nature Reserve, der snoperioden. 1981. 80:-. ISBN 91-7210-81 3-4. Eastern Sweden. 1983. 200:-. ISBN 91-721 0-073-7 (ISBN 14. G. Wistrand, Bidrag till Pite lappmarks vaxtgeografi. 1981. 91-721 0-473-2). 80:-. ISBN 91-7210-814-2. 74. Backeus, Aboveground production and growth dynamics /. 15. T. Karlsson, Euphrasia rostkoviana i Sverige. 1982. 120:-. of vascular bog plants in central Sweden. 1985. 200:-. ISBN ' ISBN 91-7210-81 5-0. 91-721 0-074-5 (ISBN 91-721 0-474-0. 16. Ed. Erik Sj ogren, Theory and models in vegetation science: 75. E. Gunnlaugsdottir, Composition and dynamical status of Abstracts. Ed. Rik Leemans, I. Colin Prentice & Eddy van heathland communities in Iceland in relation to recovery der Maarel. 1985. 120:-. ISBN 91-7210-816-9. measures. 1985. 200:-. ISBN 91-7210-075-3 (ISBN 91- 17. /. Backeus, Mires in the Thaba-Putsoa Range of the Maloti, 721 0-475-9). Lesotho. 1988. 120:-. ISBN 91-7210-8 17-7. 76. Ed. Erik Sj ogren. Plant cover on the limestone Alvar on 18. Forests of the world - diversity and dynamics (Abstracts) bland. Ecology-Sociology-Taxonomy. 1988. 320:- ISBN 1989. 240:-. ISBN 91-7210-81 8-5. 91-7210-076- 1 (ISBN 91-721 0-476-7). 77. A.H. Bja rnason, Vegetation on lava fields in the Hekla area, Iceland. 1991. 240:- ISBN 91-7210-077-X (ISBN 91-7210- Distributors: 477-6). OPULUS Press AB Limited number ofclo th-bound copies ofActa 44, 45, 46, 48, 49, Box 127, S-741 23 Knivsta 51, 52, 53, 56, 57, 61, 63, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, Sweden 76 are available at an additional cost of 50:-. (Use ISBN nos. in Phone: + 46 18 320662 brackets to order.) Nos. 1, 4, 6, 7, 9 are out of print. Fax: + 46 18 321368

Acta phytogeogr. suec. 78