MACROFAUNA ON ROCKY SUBSTRATES IN THE PORSMARK BIOTEST BASIN MARCH 1984 - MARCH 1985

Pauli Snoeijs (*) and Kerstin Mo (**) September, 1987 * Växtbiologiska Institutionen, Box 559, 75122 UPPSALA ** SNV, Miljökontrollaboratoriet, Mkk, Box 8005, 75008 UPPSALA

keywords: macrofauna, nuclear power plant, cooling water, Forsmark Biotest Basin, Baltic Sea THIS REPORT CAN BE ORDERED FROM: Naturvårdsverket Informationsenheten Box 1302 171 25 SOLNA Sweden

ISBN 91-620-3397-2 ISSN 0282-7298 CONTENTS

page PREFACE 1 1 INTRODUCTION 2 1.1 Background 2 1.2 Previous studies 3 2 DESCRIPTION OF THE AREA 5 2.1 The Biotest Basin 5 2.2 The sampling si tes 7 3 MATERIAL AND METHODS 8 4 ENVIRONMENTAL FACTORS 11 5 RESULTS 15 5.1 Species composition 15 5.2 Diversity 25 5.3 Interactions between nacrofauna and algae 31 6 DISCUSSION 34 SUMMARY 37 ACKNOWLEDGEMENTS 37 REFERENCES 38

APPENDIX I: CODES USED FOR THE DIFFERENT TAXA 43-44 APPENDIX II: SPECIES LISTS WITH ABUNDANCE SCORES 45-55 PREFACE

The research presented in this report is part of a larger project concerning the effects of cooling water flow froa the Forsaark Nuclear Power Station (Units 1 and 2) on the dynamics of the benthic ecosystea. Previous publications within the project deal with aicrophytobenthic bioaass, priaary production, environmental factors (Snoeijs, 1985, 1986), description of aacro-algal vegetation (Snoeijs, 1987) and radionuclide concentration in diatoas (Nötter and Snoeijs, 1986).

This report presents the results of an investigation of consumers (aacrofauna) occurring on rocky substrates in the hydrolittoral. Saaples fro» sites both with and without thermal discharge from the power plant were studied during the period March 1984 - March 1985.

- 1 - 1. INTRODUCTION

1.1 BACKGROUND If the environmental conditions of a biotic comunity change, its species composition will change. Thus for a proper understanding of the human iapact on the benthic systea a quantitative analysis of its constituent species is essential. Power stations using cooling water for discharging waste thermal energy change the aquatic environaent in the discharge area by an overload of temperature. Enhanced temperature changes the species coaposition of faunal communities as different species have different temperature optima and tolerance ranges. Enhanced temperature also affects algal species composition and biomass, which in its turn influences the fauna in its food supply and availability of shelter. A higher temperature increases the metabolic activity of the fauna (Ankar, 1977).

Besides temperature, other environmental factors possibly influencing the fauna are altered by the discharge of cooling water in Forsnark. The absence of ice cover in winter might for certain species result in a longer active period and/or more generations per year than under normal circumstances. Artificial flow can be of influence on the outcome of interspecific competition. Salinity oscillations in the area are relatively small, and are thus regarded as having a minor influence on the macrofauna.

The aims of this study are: 1: To compare the faunal assemblages in the hydrolittoral algal belt in the discharge area of the power plant with those in areas not receiving thermal discharge, in terms of species composition and community structure. 2: To relate the occurrence of certain macrofauna with algal cover.

- 2 - 1.2 PREVIOUS STUDIES Parallel to aacrofaunal species composition and abundance presented in this report, aicrophytobenthic bioaass (aainly consisting of diatoas), and aacro-algal species coaposition and cover-abundance, were studied froa the saae saaples (Snoeijs, 1985 and 1987). Enhanced teaperature and higher light availability (no ice cover in winter) resulted in higher diatoa bioaass throughout the year, especially in vinter and spring, and a tiae-shift of the vernal blooa towards earlier in the year. In teras of percentage cover-abundance, blue-green and green algae increased with teaperature, while red and brown algae and diatoas decreased with teaperature in the interval between the ainiaua (0°C) and the aaxiaua (25.7°C) water teaperatures that were aeasured during the investigation period. Because of an extension of the period with optiaal teaperatures for diatoas, these were aost favoured in the systea. Lower diversity and greater doainance of one or a few species over the other species was caused by theraal discharge at sites with fast-flowing water, but the opposite occurred at sites with quiescent water, aainly because of a greater number and higher abundances of blue-green algal species and thread-like green algae at the latter sites.

Hacrofauna of soft bottoas has been studied since 1978 (the Biotest Basin was built in 1977); the results have been published for the years 1978-1983 by Mo (1984). Froa 1978 to 1980 (no cooling water discharge) the total nuaber of macrofauna individuals increased, Chironomidae and Gammarus spp. were aost favoured by the construction of the basin. After the discharge of cooling water had started (1980) the total number of individuals decreased, but stayed higher than in 1978. Chironomidae, Macoma baltica and Gaamarus spp. decreased in numbers, while Corophium volutator, Paludestrina jenkinsi and Oligochaeta were most favoured by the cooling water discharge.

Chironomiuae in the vegetation at 2 to 4 m depth were studied in the area before and after the Biotest Basin was built by Eriksson (19b5). Funnel traps were used to gather the specimens. Eggs hatched at least one month earlier due to cooling water supply. Species preferring colder and more oligotrophic environments uecreased, while species preferring warmer, less exposed and more eutrophic environments increased. The occurrence of Tanytarsini and Orthocladiini decreased and that of Chi ronomini stayed about the same.

Studies on macrofauna between vegetation in areas of the Baltic Sea with similar salinities to Forsmark have been published by e.g.: Haage and Jansson (1970) and Haage (1975; 1976), for Fucus vesiculosus and Zostera marina dominated communities in the Asko area in Sweden; by Lappalainen and Kängas (1975a; 1975b) and Lappalainen et al. (1977) for Fucus vesiculosus and Zostera marina dominated communities, by Hällfors et al (1975) for Cladophora glomerata dominated

- 3 - coBBunities, by Verhoeven (1980) for Ruppia dominated coaaunities, and by van Vierssen (1982) for Zannichellia doBinated coaaunities in the Tvärainne area in Finland (see Fig.l). The Cladophora belt in the upper littoral of the Baltic Sea as a systea has been extensively studied by Jansson (1966, 1967, 1969 and 1974). The Cladophora belt is a nursery ground and substrate for faunal organises (Jansson and Wulff, 1979).

ATLANTIC OCEAN USSR

USSR

SOUTHERN RK0N»A BALTIC PROPER BASIN

FRG POLAND

Fig.l: Location map of the Porsmark Biotest Basin _ 4 - 2^ DESCRIPTION OF THE AREA

2.1 THE BIOTBST BASIN The study area is located near the Forsmark Nuclear Power Station on the Swedish east coast, about 70 km north of Uppsala at the southern end of the Bothnian Sea (see Fig.i). The power plant consists of 3 boiling water reactors. Unit 1 (900 HV) became operational in 1980; Unit 2 (900 HU) has been operating since 1981, and Unit 3 (1050 HU) since 1985. The total electrical output for the units 1 and 2 together is thus 1800 HV, but the total thermal output is 5400 HV. This overdose of thermal energy is taken away by cooling water. The cooling water for the power station is taken from Asphällsfjärden, which is connected to Oregrundsgrepen and has a salinity of 5-6 °/oo. It is led into the units 1 and 2 via inlet conduits and is heated up as it passes through the reactor cooling system. A tunnel under the sea-bed of 2350 m length carries the heated water out into the Biotest Basin (see Fig.2), from where it is released into the sea. The (artificial) Biotest Basin may thus be regarded as something between a river and a lake, with more features of one or the other at different sites within the basin. The Biotest Basin has a surface-area of 0.9 km2, a mean depth of 2.5 m, and a maximum depth of 5 m; its total volume is 2.3OO.OOO m3 (Andersson, 1983). The construction, connecting five small islands with dams, was finished in 1977, and the supply of cooling water was started during the second half of 1980. Leakage through the dams is about 6% of the flow. The bottom of the Biotest Basin consists of solid rock, sand and stones. Oregrundsgrepen is an area of little organic sediments, but in the Biotest Basin at less exposed, deeper sites, organic material has been accumulating since the power station started its operation. The water is heated 8-10°C as it passes through the reactor cooling system; this is also the temperature elevation in the larger part of the basin, as compared to natural waters in its surroundings. The lagoon (see Fig.2) has a lower temperature than the rest of the basin. The vertical temperature variation is generally only a few tenths of a degree Celsius, and seldom greater than 1°C (todersson, 1983). The cooling water flow rate at full operation is 86 mVs. This results in a flow rate at the outlet of 2 m/s, and for the main flow within the basin, 10-30 cm/s (Andersson, 1983). Most of the water (70-90%), is transported between the intake channel of the power station and the outflow channel from the Biotest Basin within 3-6 hours, where it flows fastest. The lagoon, an area partly separated from the rest of the basin by a ca. 400 m long pier, has a retention time of up to a few days: here the water is quiescent. Part of the lagoon is closed off from the rest of the basin; four grey seals live here. There is a stand-by outlet where part of the cooling water can be released directly from the tunnel into the sea. On average 25£ of the cooling water flows through the Biotest Basin if the stand-by outlet is open (Sandström, pers.comm.).

- 5 - FORSMARK NUCLEAR POWER STATION

o.»

Fig.2: The Forsmark Nuclear Power Station and the Biotest Basin, showing the sampling sites. During the sampling period unit 3 was not yet operational.

- 6 - No chemicals are used to diminish fouling organisms in the cooling water tunnels; mechanical cleaning with small rubber balls is applied. In general overhaul of the power station takes place in summer, during which each unit is turned off for a period. For sore information see Forsaarks Kraftgrupp and SNV (1982), Grinas (1979) and Sandström (1985). For the motivation of the authorities in building of the Biotest Basin, see Vattenfall (1972). 2.2 THE SAMPLING SITES Eleven sites (named A to K), in and outside the Biotest Basin, were chosen for sampling according to differences in the environmental factors temperature and current. A 'site' includes 10 m along the water line. Site G in the intake channel can be considered the reference site for temperature. Sites F, A and E follow the main flow of the cooling water. Site A (stand-by outlet) only receives cooling water if the stand-by outlet is open (see Snoeijs, 1985). Sites C, I and K are sites inside the Biotest Basin with more or less quiescent water. Sites B, D, H and J are sites outside the Biotest Basin with »ore or less quiescent water, of which B and D are slightly artificially heated by the leakage of heated water through the dams at the western side of the basin (see Andersson and Hillgren, 1986); this leakage prevented an ice cover in winter at site D, but not at site B. Sites I and J are both sites with very shallow water and a relatively high accumulation of dead and decaying plant material. For an overview of the sampling sites, see Table 1; for more extensive site descriptions, see Snoeijs (1985).

TABLE 1: THE SAMPLING SITES FLOW AVERAGE TEHPERTATURE SITE SITUATION FACTOR ANOMALY (°C) ICE COVER A stand-by outlet 3 or 6 5.9 no B outside basin 3 2.1 yes C inside basin 4 8.2 no D channel unit 3 1 1.7 no E outlet 6 7.8 no F inlet 6 9.3 no G intake 5 0.0 no H outside basin 2 0.6 yes I inside basin 1 4.3 no J outside basin 1 1.3 yes K lagoon 2 6.4 no FLOW FACTOR: 1: stagnant-quiescent, 2: quiescent, 3: quiescent-natural waves, 4: very slowly flowing, 5: flowing, 6: fast-flowing, AVERAGE TEHPERTATURE ANOMALY: average temperature minus the average temperature at site G for the period March 1984 - March 1985 (in °C). - 7 - 3. MATERIAL AMD METHODS

Saaples were taken every third week froa March 1984 to March 1985, that is 18 tines altogether. During each sampling day all 11 sites Mentioned in 2.2 were visited. Vhole coMiunities were saapled: for each saaple, eight stones (with a diaaeter of 7-12 ca) were sampled randomly froa a depth of 20-50 ca. Usually four saaples per site vere taken, on a fev occasions three or five. The investigated stone-area per saaple vas 200-400 ca2. The same type of stones occurred at all saapling sites because of the use of dynaaite in Forsaark.

In these studies, aacrofauna has been defined as the aniaals retained on a sieve of 1.0x1.0 aa aesh, which agrees with current Baltic Standard Methods (Dybern et al.t 1976). In the laboratory the living aaterial was separated froa the stones as far as possible, and by seiving through 1 aa aesh and sorting, initially divided into three subsaaples: "aacrofauna" (including gastropod eggs), "aicro-algae" (aainly diatoas) and "aacro-algae". All subsaaples were fixed with 96? ethanol. After drying, the stones were investigated for crust-foraing algae and aniaals. Under a aicroscope at lOx to 50x Magnification the algal saaples were studied and the aniaals (>laa) still occurring here were separated froa the algae. Neiofauna (0.06-1 aa: Kängas, 1978) was also considered if encountered, but no quantitative counts were Bade.

In total 690 saaples were studied for faunal species coaposition; the aniaals vere identified and counted. For colony-foraing aniaals abundance was estiaated according to a 1-9 scale, based on X cover on the stones (Electra crustulenta), or X cover within the Macro-algal saaples (Hydrozoa and Porifera). These abundance scores were transforMated to a density scale to be able to include the colony forming aninals in the diversity calculations. The resulting 3-5 species lists per site/date were combined into one list because of differences between saaples from one site/date, due to patchiness.

TABLE 2: ABUNDANCE SCALE SCORE COVER AVERAGE DENSITY (m-1) RANGE (m-1) 9 76-100 X 7500 >5000 8 51-75 X 2500 1001-5000 7 26-50 X 750 501-1000 6 11-25 X 375 251-500 5 6-10 X 125 101-250 4 1-5 X 75 51-100 3 1-0.1 X 37 26-50 2 0.01-0.1 X 12 11-25 1 0.001-0.01 X 5 1-10

- 8 - DIVERSITY MEASUREMENTS

Many diversity measures are used in ecology. None of the existing indices and methods seems to be the ideal tool under all circumstances. Among the widely used methods are diversity indices (Hill, 1973; Peet, 1974; Alatalo, 1981), and dominance-diversity curves (Whittaker, 1965; May, 1975). I used the following indices:

SPECIES RICHNESS (S) = number of taxa

SHANNON-VBAVER INDEX (B'):

Index of heterogeneity, based on a combination of richness and equitability (Peet, 1974). Thus the more species there are, and the more nearly even their distribution, the greater H'. The minimum value of H' is 0 and its maximum value is In S. S H' = - sum p . In p i=l i i where S = number of taxa and p = % importance of the i-th taxon (i = 1,2,3 S) i

SIMPSON'S INDEX (L):

Index of the concentration of dominance, based on the probability that two individuals selected at random from a sample will belong to the same species (Peet, 1974). Thus the more one or few species are dominant over the rest of the species, the higher L. The minimum value of L is 0 and its maximum value is 1. S 2 L = sum p i=l i where S = number of taxa and p = % importance of the i-th taxon (i = 1,2,3 S) i

- 9 - EVENNESS MEASURE OF PIBLOU (J'):

Based only on the evenness of the distribution of importance betveen species (Peet, 1974). Thus the higher the evenness, the more equal the species are in importance. J' = H'/H' max vhere H' = In S max and S = number of taxa

DOMINANCE-DIVERSITY CURVES:

To visualise the species-abundance relationships, diagrams can be made in which the logarithm of the X importance is plotted against the species rank number (Whittaker, 1975).

- 10 - 4. ENVIRONMENTAL FACTORS

WATER TEMPERATURE

Table 3 gives the water temperature at the sampling dates and the average temperature anomaly for the sampling period, related to the average temperature at the reference site G, for all sites.

TABLE 3: WATER TEMPERATURE THROUGHOUT THE YEAR (in °C)

SITE: DATE: A B C D E F G H I J K

840228 9.7 ice 9.8 2.6 9.4 10.6 0.0 ice 2.3 ice 7.6 840320 8.7 ice 9.4 3.8 9.1 10.8 0.3 ice 2.6 ice 6.4 840410 9.8 7.8 11.8 8.0 11.6 11.8 2.2 3.8 8.7 ice 10.8 840502 16.5 11.4 14.7 8.9 13.3 15.2 7.5 9.5 13.7 12.2 13.7 840523 16.1 14.3 19.1 15.5 19.2 19.5 11.8 15.2 19.1 19.3 18.7 840612 17.5 15.7 20.4 14.8 20.5 21.2 13.9 14.1 19.1 16.8 20.1 840703 18.2 17.7 21.8 16.3 21.3 21.7 15.4 16.3 18.9 17.6 19.4 840724 16.1 18.5 23.0 17.1 22.0 25.2 16.2 16.3 19.4 18.9 21.0 840814 24.4 21.9 25.6 19.7 25.4 25.4 17.6 19.3 22.7 18.4 24.9 840906 22.4 18.9 23.1 14.6 22.3 24.2 14.5 15.6 20.3 15.5 20.8 840926 22.6 13.8 20.2 13.0 20.5 22.5 12.7 13.0 16.1 12.0 18.9 841016 14.9 13.8 17.5 9.6 16.6 19.5 9.9 10.0 15.6 8.1 14.8 841106 10.4 6.8 15.2 8.1 13.7 16.6 8.1 7.2 11.6 6.2 12.3 841127 9.0 3.8 14.0 5.5 13.9 15.6 5.7 4.6 8.7 2.2 11.6 841218 7.3 0.9 11.4 2.0 10.8 12.5 2.0 0.0 7.4 ice 8.5 850107 6.6 ice 9.0 4.0 8.8 10.5 0.0 ice 0.0 ice 6.3 850206 7.1 ice 10.1 3.6 9.3 11.0 0.0 ice 4.5 ice 7.0 850307 6.9 ice 10.6 1.8 10.5 11.2 0.5 ice 5.7 ice 10.3 average anomaly 5.9 2.1 8.2 1.7 7.8 9.3 0.0 0.6 4.3 1.3 6.4

CURRENT

No measurements of flow velocity were made. Instead an ordinal flow factor was estimated for each site; these can be found in Table 1. At the outlet the flow is about 2 m/s and in the main flow in the basin about 0.3 m/s at full operation of the power stations (Andersson, 1983).

- 11 - BIOTEST BASIN BALTIC SEA at Forsmark Sites: C, E , F, I, K Sites: A,B,D,G. H, J 70 J H sampling dates 60 60 J] 50 SO 40 40 30 30 20 20

i 10 10 I -O 0- -10 -10 •20 -20 •30 -30 -40 -40 -50 -50 -60 -60 -70 •70 -80 •80 90 -90J • ampling dates

— »water level I • sampling depth

Fig.3: Water level measured at the sampling day, in- and outside the Biotest Basin, throughout the sampling period

- 12 - WATER LEVEL

The annual average water level inside the basin is 30 cm higher than in the surrounding sea (based on daily averages for 1984). The same general trend in the annual water level cycle can be found both in- and outside the basin: low values during spring, and higher values during the rest of the year (highest in autumn). In Fig.3 the water level for each sampling day is given, to show where the samples were taken according to algal zonation. The tidal amplitude in this area of the Baltic is insignificant (a few cm) and does not affect the algal zonation (Waern, 1952). Inside the basin sudden artificial fluctuations might occur, depending on the cooling water flow. Water level data were obtained from SMHI.

The hydrolittoral is the part that is often dried out in spring, between the geoliitoral (the more terrestrial part of the littoral) and the sublittoral (the permanently submerged belt). The hydrolittoral is colonized anew each year by algae, and is about 0.5 m wide (Waern, 1952). The border between hydrolittoral and sublittoral is considered to be the lowest water level value measured during the year, and the border between hydrolittoral and geolittoral is considered to be the mean water level during summer (Du Rietz, 1930; 1950). These borders are drawn in Fig.3. A few of the spring samples in this study were taken partly in the uppermost part of the sublittoral, and a few of the autumn samples partly in the lower part of the geolittoral; however, the great majority of samples were taken within the half-metre defined as hydrolittoral in Fig.3.

OTHER ENVIRONMENTAL FACTORS

Other environmental factors for which data are available include nutrient concentration (orthophosphate, total phosphorus, nitrate, nitrite, ammonia, and silicon), cooling water input, cooling water pathway (stand-by outlet opened or closed), light intensity (PAR = photosynthetic active radiation), global radiation, wind direction, wind velocity, turbidity and air temperature (Nitchals, 1985; Snoeijs, 1985). In this report however the emphasis is put on temperature and current, these being the environmental factors that differ most among sites.

- 13 - TABU 4: HACROFAUIIA, HEAR ABUNDANCE PER TAXON FOR EACH SITE (in «) SITE TAXON: A B C D E F G H I J K

PORIrERA + + + _ 0.1 + _ _ + HYDROZOA 0.7 _ 0.8 0.1 4.5 14.1 11.6 0.1 0 .2 + + ELEC CHU 2.5 3.2 0.1 1.9 + 0.1 20.7 3.1 0 .3 + 0.1 TURBELL 0.? 0.6 0.1 0.1 0.1 0.1 1.4 : .1 - 0.6 0.1 PLAN TOR 1.7 - 0.9 1.0 0.1 2.2 + 0.5 + - + POCE SP 0.5 1.3 1.6 - _ - 0.2 2.6 0 .3 3.1 1.6 PROS OBS 0.4 0.2 - - - - _ _ + 0.1 - BITH TEN 0.1 + - - - + 0.4 + 5.6 3.9 - HYDR VEN 0.4 0.2 0.1 _ + _ _ 0.1 0.2 0.2 - PALU JEN 18.4 4.0 14.8 0.3 13.3 44.1 0.5 3.9 2.1 1.4 6.2 THEO FLU 6.2 3.2 14.7 4.3 5.6 5.5 0.1 1.6 1.5 4.1 3.9 NUDIBRAN - - - - - + _ - - _ LIMA CAP - - - 0.1 - 0.7 _ - - - - LYNN PER 1.1 15.5 0.4 17.7 0.1 - 2.3 14.9 2 .5 48.7 0.8 LYMN PAL - - - _ - - - _ 2.1 2.8 - PHYS TON + 0.1 _ 0.3 _ _ 1.7 + 0.4 _ PLANORBI _ - _ _ _ _ _ 0.1 0 .9 5.5 - MYTI EDU 0.1 - _ _ + _ 0.2 _ _ - - CARD SP 0.1 + + 0.6 + + 1.5 - + - 0.1 HACO BAL + - _ - _ + 0.1 _ _ _ - HERE DIV 0.1 - _ - - _ + _ _ - - OLIGOCH 4.6 5.0 9.8 7.5 23.3 8.2 6.4 2.4 14 .9 9.8 10.6 PISC GEO + 1.5 _ 0.1 - _ 0.6 0.1 _ + BALA IMP 10.0 7.8 0.1 + 4.8 0.1 0.8 17.9 - - 1.5 PRAU FLE - - _ - - - - + - - NEOM INT - - _ - - - 0.1 - - - IDOT VIR 0.7 - _ + 0.2 + _ 0.1 - - IDOT SP 0.1 - _ _ + _ _ _ _ _ - JAER ALB 8.2 8.3 _ 0.5 1.7 0.8 8.1 1.5 - 0.1 0.4 GAMM SPP 9.4 9.7 12.1 10.1 7.5 3.0 4.5 14.2 0 .1 _ 7.6 CORO VOL 0.1 - + - 0.4 + _ _ 0 .3 - 0.4 CAEN HOR - _ _ _ _ 1.4 1.8 + CAEN SP - - _ - - - - - 0 .1 - - ZYGOPT - - _ _ - - - 0.1 1.8 0.3 ANISOPT - - _ _ _ _ - - 0 .1 - - COLEOPT + - - - - - + 1.1 1 .1 0.2 + HALI SP ------0.2 0 .2 0.5 - DIPTERA - - _ ------+ - CERATOPO + - _ 0.1 0.1 + _ 1 .4 2 .9 0.3 0.3 CHIRONOM 1.3 0.1 1.0 0.8 0.7 0.1 1.9 1 .0 9.5 3.1 6.5 TANYTARS 2.0 0.2 5.5 2.4 8.8 2.7 7.8 0.7 11 .3 1.8 7.6 TANYPODT 0.6 0.5 0.2 6.0 0.1 0.7 1.4 0.3 0 .6 0.1 0.5 ORTHOCLA 27.9 37.7 34.5 42.4 26.7 16.9 20.0 25.7 32 .8 10.0 45.2 TIPULID ------1.2 0.1 - TRICHOPT 0.1 - _ 0.2 - + - _ + - - HYDROPT 0.1 0.1 1.6 _ 0.1 0.2 - - - - •f HYDR SP 1.0 0.3 1.1 1 .7 0.9 0.3 3.6 0.6 0 .2 0.5 1.5 AGRA MIC 0.3 0.1 0.4 0.2 0.7 0.1 - + 3 .5 0.3 3.5 OXYE SP - - - _ - - - - + - - CYRN SP - - - + - - - - + - + POLYCENT + + - - - - _ - - - - POLY FLA - - _ 0.4 - - 2.1 0.1 + + + POLY SP - - _ _ _ 0.7 - - - - HOLO SP ------PSYCHOMY + - + - - - + - - - - TI NO WAE 0.1 - - - - - + _ + - - LEPTOCER ------+ - - - - MYST SP ------ATHR SP + 0.1 + 0.8 _ - + 0.2 1.2 - 1.0 CERA SP 0.1 0.3 + 0.2 _ - 1.0 2.4 - - + OECE SP ------0 .1 - - LIMNEPHI 0.1 - - - 0.2 - - - 0 .7 0.3 + LEPI HIR 0.1 - + 0.2 - - 1.9 0.2 + 0.1 - LEPIDOPT ------0 .2 - - PISCES ------+ - COTT POE ------+ - - -

NR OF SPECIES: 42 26 26 31 26 26 35 35 41 33 32 + = taxon occurring with mean abundance less than 0.1 - = taxon not occurring at thin site for codes used for the different taxa: see Appendix I - 14 - 5. RESULTS

5.1 SPECIES COMPOSITION

Species lists with abundance scores can be found in Appendix II for all sites and dates. All animals found on the stones were recorded, the results are given either in number of individuals per m2 or scores according to a 1-9 abundance scale. Thus in total 66 taxa were distinguished in the species lists. The yearly mean relative abundance per taxon for each site is given in Table 4. The following 18 taxa (of 66) occur at at least 9 of the 11 sites, and score together between 80 and 99% (depending on which site) of the total abundance. Abundance and time of occurrence for each taxon, however, may differ considerably between the sites.

HYDrtOZOA BALANUS IMPROVISUS ELECTRA CRUSTULENTA JAERA ALBIFRONS TURBELLARIA (unidentified) GAMMARUS SPP. PLANARIA TORVA CHIRONOMINI PALUDESTRINA JENKINSI TANYTARSINI THEODOXUS FLUVIATILIS TANYPODINAE LYMNAEA PEREGRA ORTHOCLADIINAE CARDIUM SP. HYDROPTILA SP. OLIGOCHAETA AGRAYLEA MICROPUNCTATA

Table 4 shovs that the following taxa are proportionally more dominant OUTSIDE the Biotest Basin than inside:

sites with highest X abundance:

ELECTRA CRUSTULENTA G B H A* D TURBELLARIA (unidentified) G H A* B J POLYCELIS SP. H J LYMNAEA PEREGRA J D B H PHYSA FONTINALIS H J D B PISCICOLA GEOMETRA B G H D BALANUS IMPROVISUS H A* B JAERA ALBIFRONS-group B A* G TANYPODINAE D G ORTHOCLADIINAE B H POLYCENTROPUS SPP. G D A* CERACLEA SP. H G LEPIDOSTOMA HIRTUM G

* = Site A (stand-by outlet) sometimes receives thermal discharge

- 15 - The following taxa are proportionally more dominant INSIDE the Biotest Basin than outside:

sites with highest X abundance PLANARIA TORVA F A PALUDESTRINA JENKINSI F A C E THEODOXUS FLUVIATILIS C A F E OLIGOCHAETA E I COROPHIUM VOLUTATOR E K I TANYTARSINI I E G* K C AGRAYLEA MICROPUNCTATA I K * = Site G (intake channel) is an exception here

The following taxa are proportionally more dominant at sites with STAGNANT or QUIESCENT water, seemingly irrespective or only slightly influenced by temperature: sites with highest X abundance:

BITHINIA TENTACULATA I J LYMNAEA PALUSTRIS I J PLANORBIDAE I J CAENIS HORARIA I J ZYGOPTERA I J COLEOPTERA I H J CERATOPOGONIDAE I H CHIRONOMINI I K J TIPULIDAE I J ATHRIPSODES SP. I K D

The following taxon is proportionally more dominant at sites with PLOWING water, seemingly irrespective of temperature: sites with highest % abundance:

HYDROZOA F G E

Öregrundsgrepen has a salinity of 5-6 °/oo and the macrofauna consists of euryhaline marine species, lacustrine species, and specifically brackish-water species, or species with their main distribution in brackish waters (see Appendix I).

- 16 - PORIFERA, yellowish-white coloured colonies with needles, occurred sparcely at sites A, C, D, F, G and K (sites with heated or non-heated water, but never with ice cover). Slightly higher abundance was found in winter compared with the rest of the year. Porifera were not found at the in winter ice covered sites (sites B, H and J).

HYDROZOA consisted mainly of the species Cordylophora caspia Pallas. Hydrozoa occurred throughout the year, with higher abundance in winter and spring. Highest abundance was found at sites F, G and E (with flowing water, both heated and non-heated). At all other sites they occurred with low abundance, except for site B (outside the Biotest Basin) where Hydrozoa were not found at all.

ELECTRA CRUSTULENTA was found at all sites, the very most abundant at site G (intake channel), and more abundant at sites A, B, D and H (stand-by outlet and sites outside the basin) than at sites inside the basin. The occurrence of this species in the samples was besides on temperature and current also highly dependent on water level, and occurred therefore mostly during low water levels in spring.

Two species of TURBELLARIA were identified: Planaria torva and Polycelis sp.; other individuals belonging to this class were put together in a group called Turbellaria (unidentified). Planaria torva was most abundant at sites with heated flowing water (sites F and A), and was not found at sites B and J (outside the basin). Planaria torva also showed a tendency to occur more during winter. Polycelis rp. was most abundant at sites with non-heated, quiescent water outside the basin (H and J), and was not found at sites E and F (heated fast-flowing water) and site D. The unidentified Turbellaria occurred most abundant at sites G and A, followed by sites H, B and J; this group has thus a strong tendency to occur outside the Biotest Basin.

PROSTOHA OBSCURUM (Nemertini) was rarely found at sites A, B, I and J, predominantly in spring.

- 17 - TABLE 5a: YEARLY MEAN NUMBER OP GASTROPODS PER m2

CU: + + + + +- _ _ _ + IC: - — _ - _ - - + + + _ FF: 6 6 4 2 3-6 5 1 3 2 1 TA: 9.3 7.8 8.2 6.4 5.9 0.0 1.7 2.1 0.6 i.3 4.3 SITE: F E C K A G D B H J I

PALU JEN 2549 468 308 101 661 2 3 14 22 11 27 THEO FLU 330 201 182 45 146 2 90 38 39 96 96

LIMA CAP <1 0 0 0 0 0 1 0 0 0 0 NUOIBRAN 0 0 0 0 0 1 0 0 0 0 0

HYDR VEN 0 1 1 0 16 0 0 1 1 15 3

LYMN PER 0 5 5 9 37 36 150 98 308 682 18 PHYS FON 0 0 0 0 0 1 3 2 15 5 1

BITH TEN 1 0 0 0 8 3 0 1 1 96 45 PLANORBI 0 0 0 0 0 0 0 0 1 79 8 LYMN PAL 0 0 0 0 0 0 0 0 0 25 11

TOTAL: 2880 675 496 155 868 45 247 154 387 1009 209

TABLE 5b: YEARLY MEAN RELATIVE ABUNDANCE WITHIN THE GASTROPODS (in X)

CW: + + + + +- + IC: + + + FF: 6 6 4 2 3-6 5 1 2 1 1 TA: 9.3 7.8 8.2 6.4 5.9 0.0 1.7 2.1 0.6 1.3 4.3 SITE F E C K A G D B H J I

PALU JEN 75.6 42.3 43.4 41.2 41.5 7.9 2.5 17.1 15.0 2.6 16.6 THEO FLU 18.8 56.0 53.7 54.5 40.7 3.2 32.1 23.2 10.7 10.0 14.7

LIMA CAP 5.6 - - 0.4 - - - NUDIBRAN _ - 1.2 -

HYDR VENT - 0.1 0.7 - 4.6 - - 1.3 0.2 1.3 1.6

LYMN PER 1.5 2.2 4.3 11.9 77.0 58.6 57.7 69.0 65.6 13.9 PHYS FON 1.2 6.5 0.5 4.8 0.4 0.3

BITH TEN 0.1 - 1.3 9.6 0.2 0.2 10.3 33.1 PLANORBI - - 0.2 6.7 7.1 LYMN PAL _ 3.1 12.8

= species not occurring at this site CW = receiving cooling water (+=yes; -= no) IC = ice covered in winter (+=yes; -= no) FF = flow factor (see 2.2) TA = temperature anomaly (see 2.2)

- 18 - Ten species of GASTROPODA were found in the samples of which especially Paludestrina jenkinsi, Theodoxus fluviatilis and Lymnaea peregra were dominant. Table 5a gives the yearly mean number of individuals per m2 per site for these ten species; Table 5b gives the yearly mean of percentage abundance per site (within the gastropods). See also Fig.4. The high mean percentage (5.6%) for Limapontia capitata at site F is not representative; on 6 November 1984 very few animals occurred at site F and L^ capitata was the only gastropod, which therefore scored 100% abundance at this date and site, resulting also in a high mean percentage abundance. Nudibranchia vere of least importance within the Gastropods, and will therefore not be discussed further here.

Paludestrina jenkinsi and Theodoxus fluviatilis are favoured by enhanced temperature, as they show high mean abundance at sites F, E, C, K and A, all sites situated in the discharge area for the cooling water. At site I, also within the basin but with very shallow stagnant water, the mean abundance of these two species was comparatively low; at least some water movement seems to be favourable. T^ fluviatilis occurred mainly in spring and summer, P^ jenkinsi mainly from early autumn throughout winter.

Highest abundance for Lymnaea peregra and Physa fontinalis was found at sites G, D, B, H and J, sites that do not receive cooling water discharge. The occurrence of these species thus decreases with enhanced temperature. Physa fontinalis has a preference for sites with quiescent water (sites D and H). Highest numbers of L^ peregra were found in July-August.

Bithynia tentaculata, Lymnaea palustris and Planorbidae occurred mainly at sites I and J, with stagnant, shallow water both in- and outside the Biotest Basin. From the distribution of Hydrobia ventrosa over the different sites, no preference for either temperature or current regime can be seen; the species occurred rather rarely.

Egg capsules of Theodoxus fluviatilis were found throughout the year at all sites, and in general more at the heated sites A, C, E and F, than at the other sites. Egg-strings of Lymnaea spp. were found, mainly from May to July, in highest quantities at sites B, D, G, H and J (sites outside the Biotest Basin); they were not found at sites E and F with fast-flowing, heated water. According to Hubendick (1949) eggs of Lymnaea spp. hatch in early summer. Egg-strings of Bi thynia tentaculata were found from May to July at sites A, I, J, and K. The occurrence of the eggs is in good agreement with the occurrence of the snails at the different sites. See Appendix II for egg quantifications per sample. Eggs of Paludestrina jenkinsi hatch just before they come out of the female, so no eggs of this species are found on stones.

19 Three species of BIVALVIA were found in the samples, all with very low abundance. Myt i lus edulis occurred at sites A, E and G, sites with heated and non-heated flowing water, and was only found at times of low water level in February-April. The absence of the M^ edulis at site F and only one finding at site E (both with fast flowing heated water), might point to a preference for the colder water. Cardiurn sp. occurred at all sites, except for sites H and J; highest abundance was found at sites G and D. Cardium sp. occurred mainly in summer and autumn. Macoma baltica occurred only very rarely at sites A, F and G (with flowing, heated or non-heated water). Macoma baltica and Cardium sp. are found in much higher numbers in soft bottom samples from the Biotest Basin (see Mo, 1984) than in samples from stones.

NEREIS DIVERSICOLOR was only found at sites A (stand-by outlet) and G (intake channel), with very low abundance at both sites.

OLIGOCHAETA occurred at all sites throughout the year; highest abundance was reached in summer. Oligochaeta seemed to prefer sites with heated water (sites E and I). See also Fig.4.

PISCICOLA GEOMETRA is a fish parasite, and might as such not be considered a true benthic organism (Ankar and Elmgren, 1978). In this study the species was found with highest abundance at sites B and G, thus it seemed to prefer sites outside the basin.

BALANUS IMPROVISUS occurred at all sites, except for the sites with very shallow stagnant water (sites I and J). Highest abundance was found at sites outside the Biotest Basin (sites H, A and B), but only few were found in the intake channel (site G). The occurrence of B^ improvisus in the samples was highly dependent on waterlevel, and occurred therefore mostly during low water levels in spring.

Two species of the family MYSIDAE (Praunus flexuosus and Neomysis integer) were found very rarely, and only at site H (outside the basin). Mysidae live mainly in the free water column and may therefore not be considered true benthic organisms.

Three ISOPODA species were found in the samples: Idotea viridis, Idotea sp. and Jaera albifrons. For Idotea spp. no distribution pattern according to temperature or current over the different sites could be found. Jaera albifrons occurred with highest abundance at sites G, A and B (all three sites outside the basin), throughout the year but mainly in spring and summer. The Jaera albifrons -group occurs in the Baltic with preference for exposed places in three species: Jaera ischiosetosa Forsman mainly under stones, J_^ praehirsuta Forsman mainly between algae, and J. syei Bocquet both under stones and between alg^e. Only male specimens can be identified

- 20 - to species (Forsman, 1972).

The AHPHIPODA were represented in the samples by Gammarus spp. and Corophium volutator. Gammarus spp. were found abundantly throughout the year at all sites, except for the sites with shallow stagnant water: I (with very low abundance) and J (not recorded). During summer Gammarus spp. were most abundant at sites H, D, B, C and K, sites with slowly flowing to quiescent water both in- and outside the Biotest Basin. During winter Gammarus spp. were most abundant at sites C, A and E, sites with flowing heated water. See also Fig.4. The occurrence of Gammarus spp. is related with algal cover (see 5.3). Corophium volutator was found rather rarely at sites F, E, C, A, K and I (all receiving thermal discharge), and never at the other sites (none of which receive thermal discharge); the species shows thus a preference for the heated water. C_^ volutator is mainly a soft bottom species, which is the reason that it was not found so often in this study.

EPHEHOPTERA (Caenis horaria and Caenis sp.), ZTGOPTERA, AWISOPTERA and COLEOPTERA (Haliplus sp. and unidentified species) were found only rarely. All seemed to prefer sites with stagnant to quiescent water, both in- and outside the Biotest Basin (sites I, J, H and K)

CERATOPOGONIDAE were found with highest mean abundance at sites I and H (stagnant to quiescent water, both in- and outside the basin), mainly in summer and autumn. Ceratopogonidae live mainly in the free water column and may therefore not be considered true benthic organisms.

CHIRONOHIDAE were not identified to species but four groups were distinguished: Chironomini, Tanytarsini, Tanypodinae and Orthocladiinae. At all sites Oithocladiinae was the dominant group. Table 6a gives the yearly mean number of individuals per m2 per site, and Table 6b the yearly mean of percentage abundance per site for these four taxa (within the chironomids). See also 'ig.4. The occurence of chironomid-larvae is also related to algal cover (see 5.3), so it is best to look at the relative abundances in table 6b regarding temperature and current. Orthocladiinae occur with highest mean abundance at cold water sites with quiescent water (sites B and H), Tanypodinae at non-heated sites (sites D and G), Chironomini at sites with stagnant or quiescent water (sites I, J and K), and Tanytarsini at warm water sites and the intake channel (sites C, E, F, I and G). Orthocladiinae and Tanypodinae decreased, while Chironomini and Tanytarsini increased during winter, compared with the warmer part of the year.

21 - TABLE 6a: YEARLY MEAN NUMBER OF CBIRONOMIDS PER •'

IC: ______+ + + FF: 6 6 4 2 1 3-6 5 1 3 2 1 TA: 9.3 7.8 8.2 6.4 4.3 5.9 0.0 1.7 2.1 0.6 1.3 SITE: F E C K I A G D B H J

TANYTARS 94 142 57 197 272 103 61 64 5 13 50 CHIRONOM 9 36 8 185 332 60 26 17 2 41 145 TANYPODI 3 4 3 18 12 34 18 93 4 9 6 ORTHOCLA 546 895 652 1253 438 1861 219 994 389 2644 165

TOTAL: 652 1077 720 1652 1054 2057 323 1168 400 2708 366

TABLE 6b: YEARLY MEAN RELATIVE ABUNDANCE WITHIN THE CBIRONOMIDS (in Z)

CW: + + + + + _ _ _ _ _ IC: - - - _ - - - — + + + FF: 6 6 4 2 1 3-6 5 1 3 2 1 TA: 9.3 7.8 8.2 6.4 4.3 5.9 0.0 1.7 2.1 0.6 1.3 SITE: F E C K I A G D B H J

TANYTARS 18.2 24.5 15.2 13-1 20.4 9.1 19.7 4.3 0.5 3.0 13.4 CHIRONOM 0.3 4.4 3.2 9.4 16.4 5.9 6.8 1.5 0.3 4.6 16.2 TANYPODI 1.5 0.1 2.4 1.4 1.6 3.4 5.5 10.3 2.2 1.6 0.7 ORTHOCLA 80.0 71.0 79.2 76-0 61.5 81.6 68.0 83.9 97.1 90.7 69.7

= species not occurring at this site; * = ice covered CW = receiving cooling water (+=yes; -= no) IC = ice covered in winter (+=yes; -= no) FF = flow factor (see 2.2) TA = temperature anomaly (see 2.2)

TIPULIDAE were found only rarely at sites I and J from May to July (sites with shallow stagnant water, both in- and outside the basin).

At least 18 species of TRICHOPTERA occurred in the samples. High abundances of Hydroptila sp., Polycentropus spp., Ceraclea sp. and Lepidostoma hirtum were found at site G (intake channel, with non-heated flowing water). Considering also their relative abundances at the other sites, these taxa seemed to prefer sites with non-heated water. Agraylea micropunctata on the other hand occurred mainly at sites with stagnant to quiescent water receiving thermal discharge (sites I and K). Athripsodes sp. occurred mainly at sites with stagnant to quiescent water, both heated and non-heated. All the other Trichoptera species were found too rarely to allow comment on their occurrences.

- 22 - LEPIDOPTERA were found only at site I (with shallow stagnant water inside the basin) from February to June.

Juvenile fish occurred in the samples in April-May at two sites outside the Biotest Basin (sites H and J).

SOME NOTES ON MEIOFAUNA

During these studies the emphasis was put on benthic macrofauna. Meiofauna was also considered if encountered, but no quantitative counts were made. The meiofauna on the stones consisted mainly of Nematoda, Acarina (of which 80-90% belonged to the Halacaridae), Cladocera, Copepoda and Ostracoda. Especially striking was the great increase of Acarina at the ice-free sites in winter. A sample of Ostracods, randomly taken from different sites and dates was analysed by Heinz Peper, Hamburg, FRG (see Table 7). The role of the meiofauna in the system should not be underestimated; Ankar and Elmgren (1976) found for the Asko area (see Fig.l) the relation between macro- and meiofauna to be of 8:1 in dry weight and 2:1 in annual production. Meiofaunal groups such as nematods and harpacticoid copepods are also important as grazers on diatoms (Admiraal et al., 1983; Jensen, 1984). Studies on meiofauna may be recommended for the Biotest Basin.

TABLE 7: OSTRACOD SPECIES OCCURRING IN THE FORSMARK AREA

SPECIES: NUMBER OF INDIVIDUALS:

Sarscypridopsis aculeata (Costa, 1847) 112 Heterocypris salina (Brady, 1868) 71 Cytherura gibba (O.F. Muller, 1785) 58 Xestoleberis aurantia (Baird, 1838) 36 Candona Candida (O.F. Muller, 1776) 16 Cyprideis torosa (Jones, 1850) 8 Loxoconcha rhomboidea (Fischer, 1855) 8 Cytheromorpha fuscata (Brady, 1869) 6

total: 315

(see also Enckell, 1980)

- 23 MLUDESTRMA THEOOOXUS LYMNAEA OLIGOCHAETA GAMMARUS tpp JENKINSI FLUVIATILIS PEREGRA

18 27 0 10 27 6 9 IQ 27 ie 27 watar tamparatura <"C>

CHIBOMOMINI TANITARSINI TANYPODINAE ORTHOCLAOIINAE

|I

trålar 'amparalura TO

Pig.4: Relative abundances of some dominant taxa as a function of temperature, irrespective of site and date.

- 24 - 5.2 DIVERSITY

Species richness (S), the Shannon-Weaver Index (H'), Simpson's Index (L) and evenness (J') were calculated and dominance-diversity curves were made for clusters of sampling dates for all sites. Calculations were done seperately for the periods May-November (11 sampling dates) and December-April (7 sampling dates), as no samples could be taken at sites B, H and J during winter because of the ice cover.

The results from the diversity calculations are given in Table 8 and Fig.5, and the dominance-diversity curves in Fig.6.

MAY-NOVEMBER: Following the cooling water flow, diversity decreases along a gradient from the intake channel (site G) to the stand-by outlet (site A), the inlet channel (site F) and ultimately the outlet channel (site E). The sites with quiescent or slowly flowing water inside the Biotest Basin (sites K and C) also have lower diversity than the sites with quiescent water outside the basin (sites B and H). Comparing the sites with very shallow stagnant water, diversity is higher inside the basin (site I) than outside (site J). Site D (channel unit 3) with stagnant non-heated water and no ice cover in winter, has lowest diversity compared with all the other sites.

DECEMBER-APRIL: Diversity at the sites with fast-flowing water is highest at the stand-by outlet (site A), followed by the intake channel (site G), and lowest at sites F and E with fast flowing heated water. During this winter the stand-by outlet was hardly used (Snoeijs, 1985); the water at site A had thus only a very small temperature anomaly during this period; The same trend as during the rest of the year, with decreasing diversity following the cooling water flow, can thus be seen in winter.

Macrofauna diversity is thus lower in the discharge area for the cooling water, except for at the sites with very shallow standing water. In December-April diversity varies more between sites (H' = 0.91 to 2.06) than in May-November (H' = 1.16 to 1.64). The mean number of taxa (S) is generally higher in winter compared with the rest of the year, exceptions are sites C and K.

Linear regression analysis showed that the variability of the Shannon-Weaver Index was only slightly more determined by the evenness component than by the number of species. Significant relationships were found both between H' and J', and between H' and S (see Fig.5). For the algae from the same samples, there was a significant relationship only between H' and J', not between H' and S (Snoeijs, 1987).

- 25 - TABLE 8: DIVERSITY INDICES

SITE N totS S H' L J'

MAY-NOVEMBER:

A 5692 36 14.8 1.39 0.42 0.56 B 906 24 8.9 1.38 0.38 0.67 C 2128 25 8.5 1.12 0.46 0.57 D 1943 24 8.4 1.16 0.45 0.60 E 3254 23 9.3 1.20 0.43 0.56 F 4160 24 8.1 1.21 0.43 0.62 G 1614 30 12.4 1.64 0.33 0.68 H 4133 34 11.7 1.53 0.35 0.65 I 1410 31 11.4 1.58 0.35 0.74 J 2764 33 10.7 1.26 0.46 0.56 K 2432 28 11.9 1.29 0.43 0.55

DECEMBER-APRIL:

A 2465 39 19.0 2.07 0.19 0.72 B * * * * * * C 850 19 8.1 1.55 0.27 0.76 D 1209 25 11.0 1.51 0.35 0.65 E 2480 21 10.9 1.38 0.40 0.59 F 6523 17 9.3 0.91 0.58 0.41 G 2460 27 14.1 1.66 0.31 0.64 H * * * * * * I 2690 38 14.7 1.78 0.23 0.73 J * * * * * * K 1865 23 11.0 1.61 0.28 0.72

totS = total number of species N = mean number of individuals per m2 S = mean species richness H' = mean Shannon-Weaver Index L = mean Simpson's Index J' = mean evenness measure of Pielou * = no samples taken because of ice cover

- 26 - MAY-NOV DEC-APR

>T=0.06*2.0«.r R'=0.55 w-= -O.Oe+2.47J R»=070 3 *• 0.78*0.058 R'=0.40 w ' 0.65* 0.07 S R =0«1 3 H-» 2.78 - 3.S4L *4M I R'=0.89 K-= 2 42 - 2 83 L R =O93 20 20 s S

Land J Lend/ 15 3.00 15 3.00

• • i f P- W 2.00 1.00 10 2 00 .'* 1.00 A. 4 » 0 . •" '•j * ..... '"

f' .»- •X /^' s/ 5 1.00 O.SO 5 1.00 .7 0.50

'—* —L

•L

0 0 0 0 0 c b E F J K B A H 1 G- |M« r E 6 c~TT G r lit* • • • Q D A O • O A • • • * • • *

Fig.5: Diversity indices for the different sampling sites and the equations of the linear regressions (ordered according to H').

- 27 - 100 •(Metas rand

g wo. 3100

40 ao rank

Fig.6: Dominance-diversity curves for the period May-November

- 28 - g «0 tit» A "• C >,!• E •"• F | DEC - «P«

40 60

g"»! MM K ! DEC - APS

\

40 •paciflt rank

Pig.6 (continued): Dominance-diversity curves for the period December-April

- 29 - % so* GAMMARUS spp.

s 4oo

c £ 30° E

200 D=-155+ 104 C R2=0.67

100

ao 2.0 3.0 4.0 5.0 6.0 mean cover macro-algae N CHIRONOMIDAE •H

2500-

2OOO-

1500

/ .1 •E 1000 / D=- • C / R2=0.37 #F n = 11 500

/G*

0- OX) 1.0 2.0 3.0 4.0 5.0 6 mean cover macro-algae

Pig.7: Yearly means of faunal density related to yearly means of macro-algal cover for Gammarus spp. and Chironomidae.

- 30 - 5.3 INTERACTIONS BETWEEN MACROPAUNA AND ALGAE

Mutually beneficial relationships occur between animals and algae on the stones in the hydrolittoral. The filamentous structure of the algae acts as a sieve, concentrating particulate organic matter in 'interstitial' water, which becomes then available for consumption by animals. The animals transform the particulate organ.c matter through respiration and excretion to nutrients which can be used by the algae (Jansson, 1974; Jansson and Vulff, 1979). Animals also clean algal filaments from epiphytes by eating them, so more light becomes available for photosynthesis by the filamentous algae.

The diet of benthic animals is poorly known, particularly in relation to diatoms as a food source. 'Phytoplankton' is often mentioned as being ingested by benthic consumers, but in fact, examination of species lists show that this 'phytoplankton' consists of resuspended benthic species (Plante-Cuny and Plante, 1984). Table 9 is an attempt to make a brief summary of the main food items for the in this study encountered macrofauna organisms. Of the in the samples most dominant taxa, gastropods, oligochaetes, gammarids, chironomids and caddis flies are the main gioups consuming benthic diatoms.

By using linear regression between macro-algal cover (1-9 cover/abundance scale) and density of Gammarus spp. and Chironomidae (in number/in2), significant relationships were found (see Fig.7), the intercepts of the regression equations are, however, not significant. Yearly means per site were used in regression analysis to account for seasonal effects. No significant relationships were found between macro-algal cover and the other seven investigated macrofaunal groups (Balanus, Turbellaria, Gastropoda, Bivalvia, Oligochaeta, Jaera spp., and Trichoptera).

By using linear regression between diatom biomass (in g/m2) and density of the same 9 macrofaunal groups as in linear regressions with macro-algal cover (in numbers/m2), no significant relationships were found.

- 31 - TABLE 9: MACROFAUNA ENCOUNTERED, WITH THEIR MAIN FOOD SOURCES

TAXON: FEEDING TYPE/MAIN FOOD ITEMS: REFERENCE:

PORIFERA suspension feeders: Wetzel, 1983 bacteria and particulate detritus

HYDROZOA carnivores: zooplankton Wetzel, 1983 Cordylophora caspia even Arndt, 1965 chironomid-larvae

ELECTRA suspension feeder Pandian, 1975

TURBELLARIA carnivores: small invertebrates Wetzel, 1983 diatoms (Provortex balticus) Jansson, 1966

PROSTOMA carnivore Jansson and Wulff, 1979

GASTROPODA deposit feeders: bacteria and Ankar, 1977 micro-algae (diatoms)

BIVALVIA MYTILUS suspension feeder: bacteria and Ankar, 1977 phytoplankton

CARDIUM suspension feeder Jansson and Wulff, 1979

MACOMA suspension and deposit feeder: Ankar, 1977 bacteria, micro-algae (diatoms), protozoa

NEREIS carnivore Jansson and Wulff, 1979

OLIGOCHAETA deposit feeders: bacteria, Ankar, 1977 micro-algae and protozoa

PISCICOLA ectoparasite on fish

BALANUS suspension feeder Jansson and Wulff, 1979

MYSIDAE omnivores: small zooplankton, Wetzel, 1983 phytoplankton, particulate detritus

ISOPODA omnivores: plant and animal matter Wetzel, 1983 IDOTEA mainly diatoms and filamentous Haage, 1975 algae Jansson, 1974

- 32 - TABLE 9: HACROFAUNA ENCOUNTERED, WITH THEIR MAIN FOOD SOURCES

TAXON: FEEDING TYPE/MAIN FOOD ITEMS: REFERENCE:

GAMMARUS omnivores: detritus, Haage, 1975 dead zooplankton, Jansson, 1969 filamentous algae, diatoms, adults also animals (dead or alive)

COROPHIUM deposit feeder: bacteria, Ankar, 1977 protozoa, diatoms Fenchell et al., 1975 Nielsen and Koefoed, 1982

CAENIS paniculate detritus Wetzel, 1983 epiphytic micro-algae (diatoms)

ODONATA carnivores Wetzel, 1983

HALIPLUS omnivores: filamentous algae, charophytes

CERATOPOGONIDAE particulate detritus Wetzel, 1983

CHIRONOMINI carnivores or plant matter/detritus Merritt and TANYTARSINI plant matter/detritus Cummins, 1978 TANYPODINAE carnivores ORTHOCLADIINAE plant matter/detritus

TIPULIDAE decomposing vascular plant tissue Wetzel, 1983

HYDROPTILIDAE filamentous green algae Nielsen, 1948 Hickin, 1967

POLYCENTROPIDAE carnivores Wetzel, 1983 POLYCENTROPUS carnivore Haage, 1975

PSYCHOMIIDAE micro-algae (diatoms) and Wetzel, 1983 particulate detritus Lepneva, 1964

LEPTOCERIDAE living vascular plant tissue, Wetzel, 1983 macro-algae, epiphytic micro-algae (diatoms)

LIMNEPHILIDAE decomposing vascular plant tissue Wetzel, 1983

SERICOSTOMATIDAE plant material and detritus Lepneva, 1966 Wiggins, 1977

LEPTOCERIDAE living vascular plant tissue, Wetzel, 1983 macro-algae, epiphytic micro-algae (diatoms), particulate detritus

- 33 - 6. DISCUSSION

This report is based on 181 macrofauna samples from 11 sites and 18 dates distributed over a year, each sample being a composite of 3-5 subsamples; thus the material is large enough to draw general conclusions about differences in occurence of the species between sites. Often yearly mean abundances per site were compared among sites, ignoring seasonal variation, although the occurrence throughout the year also was mentioned for most of the animals.

The hydrolittoral zone in the Baltic Sea is greatly influenced by the yearly variation of water level. In the case of sessile animal species, fluctuations in water level have certainly influenced the results, but as the fluctuations are the same for all sites, this effect largely disappears by comparing temporal means for the different sites.

The abundances of macrofaunal taxa on rocky substrates in the hydrolittoral zone of the Forsmark Biotest Basin is influenced by the supply of cooling water. The active season of the macrofauna is longer inside the basin because of the higher temperature. The lack of an ice cover also caused enhanced light availability for algae, and thus an increased food source for the macrofauna.

Seven taxa were found to be favoured by the heated water: Planaria torva, Paludestrina jenkinsi, Theodoxus fluviatilis, Oligochaeta, Corophium volutator, Tanytarsini and Agraylea micropunctata. Of these seven taxa P^ jenkinsi, T^ fluviatilis and Oligochaeta are quantitatively the most important: they are often dominant, and they are consumers of benthic diatoms, the algal group that is most favoured by the heated water. (Snoeijs, 1985; 1987). Thirteen taxa prefered sites with non-heated water, having higher relative abundances outside the Biotest Basin compared with inside; and in some cases almost comletely lacking inside. These thirteen species are: Electra crustulenta, Turbellaria (unidentified), Polycelis sp., Lymnaea peregra, Physa fontinalis, Piscicola geometra, Balanus improvisus, Jaera albifrons -group, Tanypodinae, Orthocladiinae, Polycentropus spp., Ceraclea sp., and Lepidostoma hirtum.

Eight species of gastropods were found abundantly enough to allow comparisons between si':es; the cooling water supply was found to affect most of them. Paludestrina jenkinsi and Theodoxus fluviatilis occured mainly at heater1 sites; Lymnaea peregra and Physa fontinalis at non-heated sites (the latter more at sites with quiesent water); Bi thynia tentaculata, Planorbidae and Lymnaea palustris occurred mainly at sites with quiescent water, irrespective of the temperature anomaly. Only Hydrobia ventrosa showed no clear preference for temperature or current. Haage (1975) also mentions that L^ palustris, P^

- 34 - fontinalis and B_^ tentaculata have a weak tolerance to exposure, while T^ fluviatilis is often found in places with a strong wave action.

In a study of soft bottom macrofauna in the Biotest Basin Mo (1984) concluded that Corophium volutator, Paludestrina Jenkinsi and Oligochaeta are most favoured by the cooling water supply. The same taxa were also found to be favoured on rocky substrates by the cooling water supply (this report), although Corophium volutator occurs mainly on soft bottoms, and was not found very abundantly on the stones.

Eriksson (1984) investigated chironomids in the Biotest Basin. He found that the occurrence of Tanytarsini and Orthocladini decreased, and that Chironomini stayed about the same, compared with the situation before cooling water discharge in the area had started. In the case of Orthocladiinae and Chironomini Eriksson obtained similar results to those in this report; for Tanytarsini, however, we found an increase with cooling water supply. As Erikssons samples were taken at depths of 2 to 4 m, the discrepancy in the results may be explained by difference in water depth.

The sessile animals Hydrozoa and the bryozoan Electra crustulenta, were mainly found at sites with flowing water, Balanus improvisus mainly at sites subject to natural waves. Water movement determines the relationship between sessile organisms adapted to turbulent water and vagile organisms adapted to more lentic conditions (Ankar, 1977). The major factor determining the distribution of Electra crustulenta on stones is light, as algal growth prevents its larvae from settling (Silén and Jansson, 1972). E^ crustulenta was very much more abundant in the intake channel to the power plant compared with the ten other sites, possibly because the site in the intake channel had the smallest yearly mean macro-algal cover. The low abundance of Electra crustulenta in the Biotest Basin might therefore be caused indirectly by the cooling water supply, namely via the enhanced growth of algae in the basin.

The occurrence of other macrofauna than E_^ crustulenta might also be influenced by the enhanced algal production in the basin, as the production of algae is a major determinant of the subsequent conditions of micro-climate, food supply, and shelter. The occurrences of Chironomidae and Gammarus spp. increase with the availability of macro-algae, and as groups (not as species) irrespective of temperature. Gammarids and chironomid-larvae are known to be closely connected to the Cladophora belt (Jansson, 1984), and Haage (1975) mentions that a large proportion of the chironomid larvae are hatched in the Cladophora belt

No significant relationships were founH between diatom biomass and macrofaunal density Diatoms are an important food source for certain macrpfaunal groups. Enhanced occurrence of

- 35 - certain mscrofauna night thus be an indirect effect of temperature, caused by the increased diatom biomass (Snoeijs, 1985). Size differences in nacrofauna sight explain the absence of a relationship here e.g. Paludestrina jenkinsi, occurring in some of the samples in very high numbers are often very small compared with Lymnaea peregra.

Nacrofaunal diversity generally decreased, and the dominance of one or few species over the rest increased, as a result of the cooling water discharge. Only at sites with very shallow, stagnant water and relatively large amounts of dead and decaying organic material the opposite effect was found. Lower diversity as an effect of the temperature anomaly was also found for the algae at the sites with flowing water (Snoeijs, 1987). At sites with quiescent water the aacrofauna had a lower diversity, but the algae a slightly higher diversity, because of the large number and abundance of blue-green algal species and filamentous green algae at those sites. At the sites with shallow, stagnant water, the diversity of both algae and macrofauna was higher inside the basin than outside.

- 36 SUMMARY

The Forsmark Biotest Basin, situated on the Swedish east '• coast, is an artificial offshore brackish lake, through which , the cooling water is channelled from the Forsmark Nuclear Power j Plant to the Bothnian Sea. The Biotest Basin is up to 10°C | warmer than the sea surrounding it, and has no ice cover in '. winter. There is an artificial, fast current in a large part of the basin. Macrofauna on stones in the hydrolittoral belt was i sampled at 11 sites in- and outside the basin every third week during one year. The numbers of individuals per m2 for each taxon were counted. Diversity indices and dominance-diversity curves were computed for each site on the basis of pooled data for the cold season, and for the rest of the year. In total 66 taxa were distinguished in ^fi^f-Pecies lists, (Ot >!iich 3 are sessile, the rest free-living.f^^^n T^ehe taxa 'recognized are favoured by the cooling water discharge, Paludestrina jenkinsi, Theodoxus fluviatilis and Oligochaeta being the most dominant. Thirteen taxa occurred more outside the Biotest Basin than inside, Lymnaea peregra rnd Orthocladiinae being the most dominant. Besides water temperature, macrofaunal species composition also depends on flow velocity, and is thus also influenced by the cooling water through the enhanced current. Algal production is also an important factor regulating macrofauna communities, creating substrate, micro-climate, shelter and food for faunal organisms. Significant relationships were found between macro-algal cover and numbers of Gammarus spp. and Chironomidae. Lower diversity and greater dominance of one or a few species over the other species was caused by thermal discharge, except for sites with very shallow, stagnant water, where the opposite was found.

ACKNOWLEDGEMENTS

We wish to thank Prof. Ulf Grimas (SNV) and Dr. I. Colin Prentice (Växtbiologiska Institutionen) for critically reading the manuscript and offering valuable suggestions for improvements. Dr. Heinz Peper (University of Hamburg, FRG) kindly identified ostracods, and Jan Andersson (SMHI) provided water level data. These studies were financially supported by a giant from the National Swedish Environmental Protection Board (SNV) to Pauli Snoeijs.

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- 42 - APPENDIX I: CODES USED FOR THE DIFFERENT TAXA

(systeatatics according to Brohner, 1974) * = sessile aninals in colonies, the rest are free-living aniaals F-freshwater species; B=brackish-wat»r species; M-urine species

CODE:

PORIFERA PORIFERA *

COELENTERATA HYDROZOA (mainly: CORDYLOPHORA CASPIA Pallas) HYDROZOA * B

TENTACOLATA BRYOZOA Electra crustulenta (Pallas) ELEC CRU * B

PLATHELMINTHES TURBELLARIA TURBELL Planaria torva O.F. Miiller PLAN TOR r Polycelis sp. POCE SP r NEMERTINI Prostoiaa obscurun Schultr» PROS OBS B

MOLLUSCA GASTROPODA PROSOBRANCHIA Bithynia tentaculata (L.) BITH TEN r Hydrobia vantrosa (Montagu) HYDR VEN B Paludastrina jankinsi (Snith) PALU JEN B Thvodoxus fluviatilis (L.) THEO FXU FB

OPISTHOBRANCHIATA (»NUDIBRANCHIATA) NUDIBRAN Limapontia capitata (O.F. Milllvr) LIMA CAP B

PULMONATA Lymnaea p«r*gra (Mullet) LYMN PER F Lymnata palustris (Hiill«r) LYMN PAL F Physa fontinalis (L.) PHYS TON F Planorbidae PLANORB

BIVALVIA ANISOHYARIA Mytilus adulis L. MYTI EDU M

EULAMELLIBRANCHIATA Cardiun sp. CARD SP Macoma baltica (L.) MACO BAL BM ANNELIDA POLYCHAETA Narais divarsicolor O.T. Miillar NERE DIV M

OLIGOCHAETA OLIGOCH

HIRUDINEA Piscicola gaomatra (L.) PISC GEO F

ARTHROPODA CRUSTACEA CIRRIPEDIA Balanus improvisus Darwin BALA IMP M

MALACOSTRACA MYSIDACEA Praunus flaxuosus (O.F. Miillar) PRAU FLE M Naomysis intågar (Laach) NEOM INT BM APPEMDII I: CODES USED FOR THE DIFFEUHT TAXA (continual)

ISOPODA Idotaa viridis 'Slabbar) IDOT VIR BM Idotaa sp. IDOT SP Jaara albifrons Laach -group JAER ALB BM AMPHIPODA Gaaatrus spp. GAMH SPP Corophiua volutator (Pallas) CORO VOL M

TRACHEATA INSECTA <*HEXAPODA)

EPHEMOPTERA Caanis horaria |L.) CAEN HOR P Caanis sp. CAEN SP

ODONATA ZYGOPTERA ZYGOPT ANISOPTERA ANISOPT

COLEOPTBRA COLEOPT Haliplus sp. HALI SP F DIPTERA DIPTERA

CERATOPOGONIDAE CERATOPO

CHIRONOMIDAE CHIRONOMINAE CHIRONOMINI CHIRONOM TANYTARSINI TANYTARS TANYPODINAE TANYPODI ORTHOCLADIINAE ORTHOCLA

TIPULIDAE TIPULID TRICHOPTERA (juvenila) TRICHOPT F

HYDROPTILIDAE HYDROPT k . Hydroptila sp. HYDR SP Agraylaa micropunctata Curtis AGRA MIC Oxyathira sp. OXYE SP

POLYCENTROPIDAE POLYCENT k . fc. Cyrnus sp. CYRN SP Polycantropus tlavomaculatus Pictat POLY FLA Polycantropus sp. POLY SP Holocantropus sp. HOLO SP

PSYCHOMYIIDAE PSYCHOMY k . Tinodes waenari L. TI NO WAE

LEPTOCERIDAE LEPTOCER k . Hystacidas sp. MYST SP Athripsodas sp. ATHR SP Ceraclaa sp. CERA SP Oacatis sp. OECE SP

LIMNEPHILIDAE LIMNEPHI F

S ERICOSTOMATIDAE LapidoRtoma hirtum (P.) LEPI HIR F

LEPIDOPTERA LEPIDOPT

VERTEBRATA PISCES (juvanila) PISCES Cottus poacilopus Heckel Ijuvanila) COTT POE F AP™»rx II: SRCIES UST WT1n ABI•DMCt SCOUS -- SIR A (stånd-ty outlet)

DAY: 28 20 10 02 23 12 03 24 14 06 26 16 06 27 18 07 06 07 Ml »Win* •r •4 M r\ m M nuiwi n • K n U U r n

B2): HACROFAUHA (number of individuals per TURBELL 64 74 43 7 84 35 - - 110 147 - 8 - 23 10 28 - _ PLAN TOR 17 _ _ - - 12 _ - 110 220 16 347 _ 154 69 - - 32

POCE SP 12 57 _ - 19 23 _ - _ 24 _ _ • _ 15 _ - 93 39 PROS OBS 28 BITH TEN 6 12 _ 6 _ 99 _ _ _ _ _ 19 _ HYDR VEN 46 11 24 7 9 12 _ - 55 85 - - _ 15 - - - 16 PALU JEN 214 23 6 - - 17 - 15 144 61 1595 7444 7 600 128 601 937 103 THEO FLU 497 583 190 22 84 75 60 151 133 354 - 74 7 239 - 77 46 32 LYMN PER 75 6 18 14 9 184 60 - 276 12 - - - - - 7 - - PHYS FON MYTX EDU 56 C1 CARD SP 6 6 _ _ _ _ 265 49 _ _ _ _ MACO BAL 6 - _ - - - - - 11 ------7 - - •jrgp PTV £ 1 Q • nLnL U1V O o 12 46 80 _ 243 162 _ 15 144 317 33 25 1078 49 37 OLIGOCH 482 PISC GEO - 6 _ - - _ _ - - 12 ------_ BALA IMP 231 223 208 296 411 173 38 - 1436 244 _ 116 _ 616 59 684 334 150 IDOT VIS 416 57 6 7 9 46 - - 155 61 ------Trim* ^p 16 J.lA/1 if JAER ALB 727 852 330 152 439 1209 60 242 243 37 _ 8 616 _ 14 _ 8 GAKM SPP 2027 852 98 36 196 524 8 - 2243 220 - 124 7 531 40 49 278 205 CORO VOL - - - - 19 - - - - _ - - - 8 - 7 - - COLEOPT - - - - - 29 - - 11 ------CERATOPO - - - - 9 - - - 12 ------CHIRONOM 87 46 - - - 6 - 15 199 293 - 50 - 139 - 42 121 79 TANITARS 260 40 - 14 28 248 15 - 464 330 8 - - 208 - 42 130 71 TANIPODI 6 17 18 7 84 12 - - 210 110 - 25 - 100 - 7 - 8 ORTHOCLA 323 526 104 29 1587 9355 256 772 13812 4347 81 182 7 962 10 314 195 632 TRICHOPT 17 HYDROPT 19 16 HYDR SP - 103 61 - - - - - 55 110 - 41 - 192 - 70 - 32 AGRA MtC ------77 61 - 17 - - - - 56 16 Q rUuPOI vmvi ^- Ctivri y PSYCUOMY 6 _ _ _ _ _ 22 — _ _ _ TINO WAE - 6 ------33 12 _ - - - - 21 - - ATHR SP - - - _ - - - - 11 _ - - _ - - - - _ CERA SP 12 17 - - _ - - - 12 _ _ - - - - 19 16 LIMNEPHI - 6 _ ------50 - 23 - - - - LEPI HIR - - 6 ------12 - - - 15 - - 19 -

ANIMALS IN COLONIES (1-9 scale): PORITERA 1 - HYDROZOA 2 2 _ - 1 2 3 _ 1 1 2 4 _ - 2 2 - 1 ELEC CRU 4 6 5 5 5 4 - 1 1 - - - - 2 1 2 1 1

GASTROPOD EGGS (* = egg capsules 11-9 scale; •• 9 number of egg-strings per m2): * 4 4 H 4 4 3 •1 LYMNAEA** ! 65 8 _ _ • _ I 29 BITHYNIA* - - - - 12

AVERAGE MACRO-ALGAL COVER (1-9 scale): 7.3 6.8 6.4 3.5 3.3 5.0 1.5 5.0 8.0 8.3 3.8 9.0 3.0 6.0 4.3 3.0 5.0 4.0

DIATOM BIOMASS (ash-free dry weight in g/»2) 14 26 39 43 43 8 7 15 36 30 16 31 15 12 10 10 12 19 II: SKCIES UST HUH AMDMCE SCORES - SITE B (outside the basin)

DAY: 10 02 23 12 03 24 14 06 26 16 06 27 18 MONTH: A M M J J J A S S 0 N N D

HACROPAUHA (m»fcer of individuals per •2): TURBELL 7 - - - 15 12 12 12 - - - - - POCE SP ------23 12 - - 17 - - PROS OBS - 8 - 10 ------BITH TEN ------12 ------HYDR VEN - - 10 ------PALU JEN - S - 10 - _ - - 27 7 17 109 - THEO FLU 36 16 21 78 30 231 60 - - - 8 20 LYMN PER 43 65 31 39 104 - 312 396 126 22 - 109 30 PHYS FON ------12 - - - - 8 - CARD SP _ _ _ - _ - 12 ------OLIGOCH 7 - 187 - - - 23 - - 9 219 30 7 PISC GCO BALA IMP 93 16 - 49 - - 58 180 45 - - 303 170 JAER ALB 121 49 104 253 89 _ 69 72 9 - 17 34 - GAMM SPP 7 16 31 68 30 - 127 264 27 - 43 253 120 CHIRONOM ------12 12 - - - - - TANITARS ------12 - - - - 51 - TANIPODI - - 21 10 - - - 12 - - - 8 - ORTHOCLA 143 283 73 808 611 320 1017 600 18 - 9 1077 100 SttDROPT ------17 - HYDR SP - 8 - - - - 23 24 - - - - - AGRA MIC 7 ------POLYCENT ------8 - ATHR SP 7 ------CERA SP _ 16 _ _ _ _ - _ - - - 8 -

ANIMALS IN COLONIES (1-9 scale): ELEC CRO52131-431--4

GASTROPOD EGGS (' - egg capsules 1-9 seal»; ** * number of egg-strings per iti2): THEODOXUS" 4-141-45---4 LYMNAEA" - - 10 127 149

AVERAGE MACRO-ALGAL COVER (1-9 scale): 2.0 1.0 0.5 1.0 0.7 0.3 1.7 2.3 0.8 0.3 1.0 6.5 3.7

DIATOM BIOMASS (ash-free dry weight in g/ra2): 9 8 10 5 6 3 13 10 10 14 15

- 46 - APPENDIX II: SPECIES LIST WTIH ABUHDMKS SCORES - SIR C (insid* til* basin)

DAY: 28 20 10 02 23 12 03 24 14 06 26 16 06 27 18 07 06 07 MONTH: FMAMMJJJAS SONNDJ FH

MACROFAUNA (mnfcer of individuals per >2): TUBBELL __-_9-_36-_---__6-- PLAN TOR 18 -6----- 27 ----9---- POCE SP - - - - 28 71 35 12 18 - 63 8 - 36 9 - - - HVDR VEN ---9_--______s__ PALU JEN 18 - - 9 - 10 775 1456 13 53 103 17 2598 161 189 65 82 THEO FLU 722 532 6 52 130 265 9 12 471 26 - 16 - 286 134 424 44 145 LYMN PER U - - J 19 « - - 9 CMD SP ______--9______OLIGOCH 40 827 457 - - 12 18 13 32 24 25 241 9 - 7 100 BALA IMP _ 13 __ 19 __ 12 ------GAMM SPP 36 465 - 112 2908 41 44 24 302 11 116 36 377 153 109 CORO VOL ______62 ------CHIRONOM 18 - - - - 10 - 12 9 - - 16 - - 9 18 - 45 TANITARS 144 27 - 9 75 20 62 12 115 26 21 103 - 205 - 130 58 27 TANIPODI --_43 9--______ORTHOCLA 90 53 12 52 615 612 652 1144 5329 180 423 79 8 1393 45 819 87 136 HYDROPT __ 12 ______HYDR SP 162 40 - 17 - - - - 18 - - - - 27 - 6 AGRA MIC ___9______12 7 27 PSYCHOMY __-_____9______ATHR SP _---9--______6-- CERA SP _--__--_____-9-_-_ LEPI HIR ___9______

ANIMALS IN COLONIES (1-9 scale): PORIFERA __-__--i__-____-__ HYDROZOA __l______l_l_2 ELEC CRU ______i______i_

GASTROPOD EGGS (* - agg capsules 1-9 seal»; *• - nunbar of agg-strings par «2): THEODOXUS* 3237662352-1-38453 LYMNAEA** ___9 75 10 ------

AVERAGE MACRO-ALGAL COVER (1-9 scale): 5.0 4.0 2.5 2.3 3.8 5.5 1.8 5.5 7.5 0.8 1.3 2.8 0.8 5.8 3.5 5.3 5.5 6.5

DIATOM BIOMASS (ash-free dry weight in g/»2): 43 45 20 23 23 5 13 11 18 18 27 29 11 23 29 19 23 43 APPENDIX II: SPECIES LIST WITH AWMDMCX SCORES -- SITE D (chUMMl wit 3)

DAY: 28 20 10 02 23 12 03 24 14 06 26 16 06 27 18 07 06 07 MONTH: F M A H H J J J A S S 0 N N D J F H

MACROFAUNA (mufcer of individuals per •2):

PLAN TOR ______100 _ _ _ _ 14 32 61

THEO FLU 109 107 9 55 20 12 28 239 _ _ _ 7 _ 854 53 121

LYMN PER 62 20 28 63 13 189 257 1046 304 58 144 131 _ 55 157 95 69 PHYS FON _ - _ 16 _ _ _ 30 _ _ _ _ 8 _ _ _ _ _ CARD SP ------10 - 12 15 8 7 - _ _ - OLIGOCH - 7 - - 7 47 21 - 80 - 322 113 92 21 7 14 21 26 PISC GEO 12

IDOT VIR

GAMH SPP 148 154 28 142 162 59 _ 269 20 45 385 68 7 68 42 277

CHIRONOM 47 7 _ _ 7 _ 100 _ _ _ _ 89 32 26 TANITARS 31 13 - 16 - 12 - 30 398 - - _ 31 - - 512 95 17 TANIPODI 8 27 9 165 674 543 7 _ 199 _ _ _ 8 _ 34 _ _ ORTHOCLA 559 617 311 2648 364 71 139 686 8964 81 92 166 369 62 _ 1954 253 555 39 HYDR SP 16 40 19 55 196 59 _ 70 _ _ _ _ 55 _ AGRA MIC 16 - - 16 13 - - - 70 - _ _ - - _ - -

POLY FLA 16 40 _ _ 20 _ 40 ______9

20 g 1 T

ANIMALS IN COLONIES (l-<) scale): • HVDROZOA 1 ELEC CRU 3 3 2 3 - - - - 2 - - - 1 1 3 4 3

GASTROPOD EGGS (* = egg capsules L-9 scale; ** E number of egg-strings per m2): THEODOXUS 2 1 - 3 - - 1 - 3 - - _ - 2 1 5 3 3 LYMNAEA** 70 76

AVERAGE MACRO-ALGAL COVER (1-9 scale): 5.3 5.7 5.3 7.0 3.6 0.3 0.3 0.3 6.5 1.0 1.0 2.0 1.5 3.8 2.3 4.8 4.0 1.0

DIATOM B1OMASS (ash-free dry weight in

CAY: 28 20 10 02 23 12 03 24 14 06 26 16 06 27 18 07 06 07 MONTH: FNAHHJJJASSONNOJPH

HAOtorAUNA (nuabar of individuals par _2): TURBELL 11 ______13 ------30-- PLAN TOR ______21-- 28---- HYDR VEN 21 ------PALU JEN 32 - 7 - 11 65 - - 102 - 34 - 2136 208 1134 2177 2525 THEO FLU 933 267 14 19 90 240 - - 1283 43 7 - - 112 - 252 69 284 LYW PER _____ 87 ------MYTI EDO 11 ------CARD SP ______25 ------OLIGOCH 97 17 7 2180 2031 153 53 - 1296 704 82 135 242 2799 905 85 BALA IMP 408 138 132 199 203 131 - - - 14 - - - 9 22 113 43 IDOT VIR -______9 13 ______IDOT SP __-______-__-_7-- JAER ALB 86 9 - - - 153 70 - 280 57-34 - 121 - 67 26 14 GAm SPP 1996 86 28 114 305 861 9 18 1118 - 37 - 334 17 482 CORO VOL 32 9 - - 11 11 - - 521 14 - - - 9 CERATOPO ____ 11 ------10--- CMRONOM 32 ------394 - 7 8 8 28 21 148 - - TANITARS 86 9 7 - 68 11 53 73 419 474 439 210 » 196 - 430 35 43 TANIPODI ----11 __-38_7----7-- ORTHOCLA 129 78 21 74 938 2908 667 227 7306 503 528 118 78 709 31 1735 9 57 HYDROPT ______------9_44-14 HYDR SP 193 17 21 - - 33 ------22 - 85 AGRA MIC - - - - 11 - - - 559 - - - 19 - 289 52 LIMNEPHI ______14 -8 28----

ANIMALS IN COLONIES (1-9 scale): HYDROZOA 255521121122144551 ELEC CRU---1------1--

GASTROPOD EGGS (' = agg capsulas 1-9 seal»): THEODOXUS* 5326472141-1-3-334

AVERAGE MACRO-ALGAL COVER (1-9 scala): 6.7 3.8 5.2 1.5 2.5 2.5 1.8 2.0 7.8 2.0 2.0 3.8 1.0 7.0 2.3 4.5 2.8 5.8

DIATOM BIOMASS (ash-fre* dry waight in g/n2): 37 48 33 26 9 14 17 11 26 20 28 28 19 29 28 23 27 75

- 49 - APf-MDIX II: SPECIES LIST WTO MMBMK1 SCOHCS - SITS P (ialat to thm bwi_)

CAY: 28 20 10 02 23 12 03 24 14 06 26 16 06 27 18 07 06 07 MONTH: FMAMHJJJASSOHHDjrH

MACROFAUNA (timber of individuals par •_): TURBELL _-_-___- 39 __ 18 -7-38-- PLAB TOR ------441 - 17 424 - 86 - - « 13 BITH TEN _____ 22 ------PALU JEN 10388 2829 4171 - 42 5543 40 129 8690 35 43 565 - 3974 340 1386 871 6831 THEO FLU 2159 1414 862 43 .9 48S 30 12 454 9 - 18 159 23 162 42 LIMA CM> _-______-8----- CARD SP _-__-__- 65 ______HACO BAL ------13 ______OLIGOCH - - 9 514 1516 277 - - 1297 18 26 35 73 53 - 34 155 BALA IHP 90179------8-- IDOT VIR ______26 ------JAET. ALB 27 - 9 - - 222 10 12 39 ------38 8 - GAWt SPP 596 300 148 26 93 543 10 12 428 - - - 8 46 8 192 34 26 CTRO VOL _-_____- 13 ____----- CERATOPO _--______-_ 13---- CHIRONOM _ - - - _ 22 - - 130 ------8 - - TANITARS - 8 - - 8 355 30 - 674 - 17 168 - 106 - 223 68 26 TANIPODI ______52 ---8----- ORTHOCLA 9 25 46 17 110 4545 141 23 3891 53 180 247 25 146 - 300 34 39 TRICHOPT 9-_____-____------HYDROPT 33 - 31 17 - HYIW SP 72 - 9 - - 22 ------69 - 298 AGRA HIC ------143 _--_ 13 __8-

ANIHALS IN COLONIES (1-9 seal»): PORIFERA _-_-_-_l-__------HYDROZOA 7954941-2-32252825 ELEC CRU 2211------1-1--

GASTROPOD EGGS (' = »gg capsul*s 1-9 seal*): THEODOXUS* 45?426212-21-41352

AVERAGE MACRO-ALGAL COVER (1-9 seal*): 7.0 5.0 7.0 0.3 0.3 0.8 0.8 0.8 6.5 1.0 2.5 6.3 1.0 6.3 1.8 5 8 6.0 7.5

DIATOM BIOMASS (»sh-lr** dry wight in q/m2): 24 71 58 32 19 13 11 7 23 9 13 15 »13 8 11 13 5l

- 50 - APPENDIX II: SPECIES LIST WITH AH JHDNICE SCORES -- SITE G (intake channel)

DAY: 28 20 10 02 23 12 03 24 14 06 26 16 06 27 18 07 06 07 MONTH: F M A M M J J J A S S 0 N N D J T H

MACROFAUNA (number of individuals per i»2): TURBELL - 12 174 8 18 19 8 10 12 24 ______— _ 1 ft PLAN TOR g i POCE SP 6 _ _ _ 29 _ _ 12 ______BITH TEN 18 _ _ _ _ _ 8 _ 12 12 ______- _ PALU JEN - 6 ______12 • _ 18 _ _ _ - _ THEO FLU 28 1 £ NtmTRRAM nuui •tuU'i Li1 J _ _ _ _ LYMN PER 46 152 84 16 36 10 62 107 9 9 31 52 29 »UVC FrtM 1 5 rnis ruri it MVTT rnii 18 18 JJ m 11 LUU ______CARD SP 62 142 31 7 15 10 MACO BAL 9 - - - _ - - - 12 - - _ _ 12 _ - - _ NERE DIV r D ______OLIGOCH _ 29 8 137 36 146 26 53 43 PISC GEO 7 / BALA IMF 9 30 7 8 9 ______6 7 50 29 JAER ALB 120 121 710 275 116 183 8 51 124 95 9 26 - 43 - 7 13 48 GAHM SPP 55 127 70 39 - 87 - 10 25 24 18 26 44 99 7 7 6 57

CHIRONOM 138 12 '8 _ 18 _ 21 25 36 _ _ 9 62 _ 37 6 77 TANITARS 37 36 14 16 36 10 72 10 311 47 - 17 35 291 14 82 13 48 TANIPODI - 18 7 - 9 48 - _ 112 59 - 9 _ 25 _ 15 6 10 ORTHOCLA 202 582 369 94 189 68 48 164 311 261 18 156 44 439 14 337 31 613 HYDR SP 120 139 63 24 116 174 - _ 25 130 - _ - 25 _ 13 182 POLY FLA 83 42 28 _ _ 68 - - 50 190 9 - - - _ - - 67 POLY SP PSYCHOMY ______12 ______TINO WAE - - _ - _ _ - - 12 - _ - - _ - - LEPTOCER - - ______12 - ______ATHR SP CERA SP 18 36 35 16 9 _ _ _ 12 24 9 _ 19 _ 30 13 19 LEPI HIR 9 - - - 27 48 - - - 190 9 17 9 6 - - - -

ANIMALS IN COLONIES (1-9 scale):

HYDROZOA 2 _ 1 _ 1 _ _ 1 1 1 1 9 1 6 2 8 ELEC CRU 7 7 6 8 6 5 - - 4 4 - - 1 5 2 6 6 7

GASTROPOD EGGS (* = egg capsules L-9 scale; number of egg-strings per i»2 >: THEODOXUS • 2 - 1 - _ - - - 1 1 _ _ _ 2 _ 1 1 1 LYMNAEA* * - - - - 9 116 24 21 ------

AVERAGE MACRO-ALGAL COVER (1-9 scale): 3.5 2.5 3.0 1.8 0.5 0.3 1.0 0.3 1.5 1.0 1.0 1.0 1.0 3.5 0.5 1.3 1.0 2.0

DIATOM BIOMASS (ash-free dry weight in g/m2) 13 16 27 21 22 20 14 14 19 27 19 20 14 22 13 9 9 18

- 51 - APPBIDIZ II: SPECIES LIST 1WTH AlWMDAHCJ E SCORES — SITE H (outside) tbe basin)

DAY: 10 02 23 12 03 24 14 06 26 16 06 27 18 MONTH: A M M J J J A S S 0 N N D

MACROFAUNA (number of 1individual:i per «2): TURBELL 155 - - 46 35 - 84 _ 16 _ 9 _ _ PLAN TOR 155 16 ______8 _ POCE SP - - 8 23 — 13 - _ _ 33 28 _ - BITH TEN - _ _ _ 13 ______HYDR VEN PALU JEN _ _ 105 7 _ _ 121 11 38 _ THEO FLU 52 57 71 58 28 53 185 _ _ _ _ 8 _ LYMN PER 311 171 267 232 56 568 2155 117 49 22 19 23 11 PHYS TON - 104 8 _ _ 51 17 _ _ 9 _ _ PLANORBI - - _ 12 ______OLIGOCH 26 - - 12 7 13 84 _ 49 22 19 _ _ PISC GEO 26 B BALA IMP 285 213 204 465 315 13 185 100 8 11 _ 446 11 PRAU FLE - _ _ _ _ _ 34 _ _ _ _ IDOT VIR - - 8 _ _ _ 34 _ _ _ _ _ - JAER ALB 648 - 24 - - - 17 _ 16 _ _ 8 - GAMM SPP 1425 130 173 453 - _ 2256 17 24 22 104 172 _ COLEOPT 26 - 8 - _ - _ _ _ 22 _ _ - HALI SP - - - - _ _ _ 16 _ _ _ _ CERATOPO - - 102 - _ _ _ _ 56 _ _ _ _ CHIRONOM 466 - 8 - 7 26 17 _ 8 - _ _ _ TANITARS 104 _ 8 _ _ 13 17 _ 32 _ _ _ _ TANIPODI 26 5 24 _ _ _ 67 _ _ _ _ _ ORTHOCLA 674 202 165 105 1548 5416 26094 17 137 - - 16 - HYDR SP 181 5 47 ______AGRA MIC - _ - _ _ _ 84 ______POLY FLA 26 5 _ - _ 13 84 ______ATHR SP - - 24 12 7 - - - _ - - - - CERA SP - 31 24 58 _ _ 17 _ 24 33 _ _ _ LEPI HIR -. _ 24 ______CCfTT POF 26

ANIMALS IN COLONIES (1-9 scale): HYDROZOA 1 1 ELEC CRU 3 4 1

GASTROPOD EGGS (* a egg capsules 1-9 scale; < * • number of egg-string: per m2): THEODOXOS* 3 3 2 2 2 1 5 1 - 1 - 6 - LYMKAEA** - 39 337 56 — — — — — —

AVERAGE MACRO-ALGAL COVER 1-9 scale): 5.0 3.0 3.3 5.7 1.0 5.7 9.0 1.0 1.8 3 .0 2.3 4.3 0.7

AVERAGE DIATOM BIOMASS (ash-free dry weight n g/m2 : 23 19 4 7 9 10 14 7 10 15 16 11 7

- 52 - APPENDIX ][I: SPECIES LIST WITH NWRDNKX SCORES - SITS I (inside th* basin)

nAY: 28 20 10 02 23 12 03 24 14 06 26 16 06 27 18 07 06 07 MONTH: F M A M M J J J A S S 0 N N D J F H

MACROFAUNA (number of individuals p«r m2 : PLAN TOR 9 POCE SP _ 9 _ 9 _ _ _ _ 19 _ _ _ _ 34 _ PROS OBS 28 BITH TEN 44 19 104 128 60 71 12 61 81 223 ______9 HYDR VEN 11 9 - - - 14 - 12 _ _ _ 12 _ _ _ _ _ PALU JEN 22 - - - - 28 - 37 49 56 18 12 - 21 102 142 THEO FLU 186 1416 - 46 _ 28 - 12 - _ _ _ _ _ 41 LYMN PER - - 9 9 - 28 - 37 65 _ _ 110 16 41 17 _ t VMN PM 1 £ 1 A *51 1 I hl Q 1*1 TO» IrnLi Li 117 7 PHY c vntt Q M1I9 i VI» PLANORBI _ _ 15 _ _ 25 _ 18 25 _ _ _ _ 68 CARD SP 19 OLIGOCH 33 189 92 522 4167 12 37 16 465 327 12 47 28 104 34 161 GAMM 5PP ------_ 16 ______9 f*ORO VOI 9 Q LvPv V VSLJ 28 y CAEN HOR 186 198 _ 137 90 14 _ 32 _ _ ?S _ _ _ CAEN SP 27 Q ZYGOPT 44 274 _ 46 15 14 _ _ 32 19 36 12 145 51 76 ANISOPT COLEOPT 22 9 _ _ _ 410 _ 37 49 19 ______HALI SP 11 - - 18 - - - - - 19 _ _ _ - _ _ _ _ CERATOPO - 38 - 27 45 - - 37 97 93 109 12 16 _ _ _ 28 CHtRONOM 1897 2125 9 604 104 466 - 12 65 _ 36 98 _ _ 104 256 199 TANITARS 1162 1105 9 394 - 763 12 25 16 _ 109 49 _ 28 414 239 578 TANIPODI 22 28 - 27 _ 71 _ 12 49 ______ORTHOCLA 318 2833 38 256 687 410 135 37 455 130 436 552 31 16 28 704 307 511 TIPULID - - - 18 _ _ - 98 ______TPTCHOPT •i nivnui x 14 33 HYDR SP 132 X 1 AGRA MIC 230 94 76 46 45 _ _ 114 74 _ _ 21 17 66 OXYE SP 9 CYRN SP 57 POLY FLA 11 47 TTNO WAF 9 X X nj VV/UJ ATHF SP 219 349 46 30 _ _ _ 16 _ 54 ______38

OECE SP £X LIMNEPHI _ 9 ______16 _ _ 9 LEPI HIR 9 LEpTnopT 11 9 9 14

ANIMALS IN COLONIES (1-9 scale : HYDROZOA 2 5 - 1 _ 1 - 1 - - _ - _ _ - _ 2 ELEC CRU - 1 - - 1 - 1 - - - - 1 - - 2 2 1

GASTROPOD EGGS (* * egg capsules 1-9 scale; •* = number of egg-strings per m2); THEODOXUS 4 4 2 5 2 5 - 2 4 1 1 - - 1 1 3 LYMNAEA* * - - - - 15 28 12 12 16 _ _ - _ _ _ _ - BITHYNIA» _ - - - 15 14 - 110 ------

AVERAGE MACRO-ALGAL COVER (1-9 scale): 4.0 6.0 2.0 4.3 1.0 2.3 0.3 1.5 2.0 1^0 1.0 1.0 0.5 0.3 0.3 1.0 1.3 1.0

AVERAGE DIATOM BIOMASS (ash-free dry weight in g/m2): 36 34 20 36 11 11 12 25 32 12 16 11 11 11 14 11 22

- 53 - APPEMHX I] : SPECIES LIST WITH ABUNDANCE SCORES - SITE J (outsida th* basin)

DAY: 02 23 12 03 24 14 06 26 16 06 27 MONTH: M M J J J A S S 0 N N

MACPOFAWA (number of individuals per »2 TURBELL 32 13 9 - 118 - - - - - POCE SP 64 39 - - 172 265 - - 43 29

PROS OBS - - - - 15 - - - • BITH TEN 340 299 19 9 215 88 - - 86 -

HYDR VEN 21 143 _ - _ - - - - - PALU JEN 64 _ 19 - 11 - - - - 29 THEO FLU 180 352 46 9 452 - - - 19 LYMN PER 53 521 46 214 1518 1690 677 505 837 1099 344 LYMN PAL ______- _ _ 277 PHYS FON _ _ _ _ 22 15 11 _ 7 - PLANORBI _ 13 _ _ 45 151 118 54 24 335 134 OLIGOCH 149 12370 28 - 140 - - - 57 - JAER ALB _ _ - - _ - - - 14 - CAEN HOR 53 339 19 - 20S - - - 7 10 ZYGOPT - _ - - 11 - - - - 29 COLEOPT _ 104 - 18 _ _ - - - _ HALI SP 64 52 - - 129 - - - - - DIPTERA - 13 ------CERATOPO 42 91 - - 32 - - - - - CHIRONOM 138 247 9 _ 1195 - - - - 10 TANITARS 180 91 - 18 129 - 11 - 121 - TANIPODI 11 52 ------ORTHOCLA 754 352 19 160 180 237 15 22 8 57 10 TIPULID - 65 - 9 ------HYDR SP 74 39 - - 108 - - - - - AGRA MIC 85 ------POLY FLA - - - - 11 - - - - - MVST SP - - - - 11 - - - - LIMNEPHI 32 ------7 10 LEPI HIR ------10 PISCES - 13 ------

ANIMALS IN COLONIES (1-9 scale): HYDROZOA 1 - - - 1 - - - - - ELEC CRU 1 - - - 1 - - - - -

GASTROPOD EGGS (* = egg capsules 1-9 scale; •* *= number cf egg-strings per m2): THEODOXUS* 6 5 4 2 - 4 3 1 1 1 3 LYMNAEA** - - 19 178 72 11 15 - - - - BITHYNIA*' - 143 18 — ~ — — — —

AVERAGE MACRO-ALGAL COVER (1-9 scale): 4.0 9.0 1.8 0.3 1.8 3.0 0.7 0.3 O.B 1.0 1.0

AVERAGE DIATOM 8IOMASS (ash-free dry weight in g/»2) 26 31 13 18 9 16 10 9 11 10 10 APPENDIX II: SPECIES LIST WITH AHJHDMKE SCORES -- SITE K (lagoon)

DAY: 28 20 10 02 23 12 03 24 14 06 26 16 06 27 18 07 06 07 MONTH: F M A M M J J J A S S 0 N N D J r M

HACROFAUNA (number of individuals per m 2): TURBELL - - - - 23 8 - 2 - POCB SP _ 8 : _ : 7 20 44 13 22 42 ._ ! 7 9 PALU JEN 17 - - _ - - - - 9 46 15 388 33 752 159 114 142 143 THEO FLU 166 47 8 34 8 188 7 10 158 7 7 - - 16 7 50 35 54 LYMN PER - 7 - - - 44 - - - - - 21 13 64 _ 7 - - CARD SP ------18 7 15 7 - 8 - - - - OLIGOCH 70 - - 301 351 125 - - - 20 365 291 46 1056 103 44 125 -j ______/ BALA IMF 8 6 10 44 39 80 14 135 212 72 JAER ALB 17 _ _ _ - 6 _ 10 _ - 7 _ _ - 28 14 9 _ GAMM SPF 35 40 8 17 23 508 39 90 246 26 36 21 13 624 14 43 35 9 CORO VOL 9 ------9 7 15 - - 144 - 21 18 9 CAEN HOR ------18 - 7 ------ZYGOPT 7 ------7 - - CERATOPO _ : : : 10 9 7 22 21 : 16 7 18 CHIRONOH 1396 - - - 8 - 7 50 379 118 29 48 - 16 21 213 186 850 TANITARS 419 20 _ 9 8 50 _ 120 537 53 168 118 26 288 55 576 159 939 TANIPODI 17 - _ 17 - _ _ 20 62 _ _ - - 184 _ _ - 27 ORTHOCLA 489 74 8 181 901 2238 19 36R4 5722 1097 1860 623 40 736 117 1792 761 2209 HVDBOPT 27 lilUnUil i 7 g HYDR SP 183 X t 89 AGRA NIC 25 52 _ 26 20 _ _ _ 24 _ 100 97 CYRN SP g POLY FLA ______26 7 ______ATHR SP 9 - - 9 - 238 7 10 - - 7 - - 8 - - - 45 CERA SP - _ - _ _ - 30 - - - _ ------f TMMFPHT 1 fi

ANIMALS IN COLONIES (1-9 scale); DODTFFD& rUHirtKA * HVITOO7flHIUKU6UAl ELEC CFU 1 - - 1 1 1 - 1 ------*# — GASTROPOD EGGS (• = egg capsules 1-9 scale; number of egg-strings per m2): THEODOXUS• 5 2 1 1 1 4 1 4 4 1 - 1 - 1 - 3 4 4 LYMNAEA** - - - - - 10 ------D Y*VtI*JMY ti # a •7 BITnlNlA o /

AVERAGE MACRO-ALGAL COVER (1-9 scale): 6.7 2.2 0.5 0.3 1 .0 7.0 0.3 7.0 5.5 0.8 3.3 4.6 1.0 6.8 1.5 5.0 5.5 6.8

AVERAGE DIATOM BIOMASS (ash-free

- 55 -