Further Developments in Lake Brokopondo, Surinam Zônica) by SCHMIDT, G.W: Primary Production of Phytoplankton in the Three Types of Amazonian Wâters

Paginas/ Seiten REISS, F: Zur Hydrographie und Makrobenthosfauna tropischer Lagunen in den Savannen des Território de Roraima, Nordbrasilien. 367 AMAZONIANA IV I I -8 Kiel, Márz 1973 (Sôbre a hidrografia e a fauna macrobentônica de lagunas tropicais nas savanas do Território de Roraima, norte do Brasil)

SCHADEN, R: Kurze Mitteilung über die Artenzahl der Rotatorien im Amazonas- gebiet. . 253 (Comunicação rápida sôbre o número de espécies de Rotíferos na região ama- Further developments in Lake Brokopondo, Surinam zônica) by SCHMIDT, G.W: Primary production of phytoplankton in the three types of Amazonian wâters. P. Leentvaar'). I. Introduction 135 (Produção primríria do fitoplâncton nos três tipos de águas amazônicas. Research Institute fo¡ Nature Management, the Netherlands. L lntrodução)

SCHMIDT, G.W: Prima¡y production of phytoplankton in the three types of Amazonian waters. II. The limnology of a tropical flood-plain lake in Central Amazonia (Lago do At the congress of the SIL in Poland, 1965, I presented a paper on the observations Castanho ) 139 were carried during (Produçâo primária do fitoplâncton nos três tipos de águas amazônicas. which out the first filling of the newly constructed Brokopondo rnan- II. A limnologia de um lago tropical de planície inundável na Amazônia central made lake in Surinarn (LEENTVAAR, 1966). The observations were continued during the (Lago do Castanho) ) three succeeding years by J. van der HEIDE. ln 1961 the continuous research by a team years SCHMIDT, G.W: Primary production of phytoplankton in the three types of Amazonian of biologists ceased and in the following the lake was only investigated occasionally. waters. The author revisited the lake in April 1968 and it is the observations made then which III. himary productivity of phytoplankton in a tropical flood-plain lake of Central are considered here. Amazonia, Lago do Castanho, Amazonas, B¡azll . . 379 (P¡odução primríria do fitoplâncton nos três tipos de águas amazônicas. In August 1961 the level of the water near the dam was 43 metres and on April 3Oth, lII. Produtividade primríria do fitoplâncton em um lago tropical de planície inun- dável,Lago do Castanho, Amazonas, Brasil 1968, it was 41.80 metres. This shows the fÌuctuations of the water level, which may be * caused partly by the operation of the turbines and partiy by the varying amounts of preci SCHMIDT, G.W. und G. UHERKOVICH: Zur Artenfülle des Phytoplanktons pitation. The ofevaporation evapotranspiration in Amazonien 243 significance and in this connection is clear, (Sôb¡e a multiplicidade de espécies no fitoplânctol da Amazônia) but insufficient data were available at that time. Tests with water hyacinth indicated that the water loss caused by evapotranspiration was much greater than the evaporation from SCHREIBER, H: Ausbreitungszentren von Sphingiden (Lepidoptera in der Neotropis . 273 (Centros de dispersão de Esfìngídeos (Lepidoptera) na região neotrópica) a free water surface. According to the observations of the Department of Hydraulics in Su- rinam, the evaporation ol the free water surface at the dam amounted to an average of WIRTH, W.W. and F.S. BLANTON: A review of the maruins or biting midges of the 4.5 mm per day. The precipitation of Afobaka averaged 5.5 mm and at Pokigron 5.7 mm genus Culicoídes (Diptera: Ceratopogonidae) in the Amazon Basin 405 (Revisão dos maruins do gênero Culicoides (Diptera: Ceratopogonidae) na Bacia This means, that a small surplus of precipitation resulted. However, the rate of evapo- Amazônica) transpiration has not been taken into account. It must be mentioned also that two obser- vation stations for precipitation measu¡ements are insufficient and therefore the Depart- ment of Hydraulics has established several other stations in the lake area, which will give more reliable results in the future. The problem of evapotranspiration also needed more research, which has been obtained by some experiments (WEERT, v.d. & KAMERLING, * Vortrag gehalten aufdem 3. Symposium des Geographischen Institutes der Universität des Saarlandes 1967). The development of the water hyacinth in the lake in relation to water loss was of und des Max-Planck-Institutes für Limnologie, Abteitung Tropenökologie úber "Arten- und Endemiten- great interest for the managers of the tu¡bines. From 1964 the problem of chemical con- reichtum neotropischer Biome", 2. und 3.Mai1972 im MPI für Limnologie, Plön. trol was considered by the Surinam Aluminum Company, which started control by spray- * ing2 - 4 D by plane and boat. In 1968 some results were recorded: in 1966 the area çover- Conferência pronunciada no 3' Simpósio do Instituto de Geografia da Universidade do Sa¡re e do Instituto Max Planck de Limnologia, Departamento de Ecologia Tropical sôbre "Riqueza em espécies ed by water hyacinth was 41 200 hectares (53 7,) (J. van DONSELAAR, 1968), in 1968 e endemitas de bionas neotropicais", 2 e 3 de maio de 7972, no IMP de Limnologia, Plön. it'was estimated that about 40 % of the surface area was occupied by the plants. The effect olthe control of water hyacinth, together with the disappearance oltree H2S. This was always the case at wind protected locations, in tops under wateI, was clear lrom the increasing area of opelj water. As a result, wind ac- deep water often contained tion increased and this caused better nrixing ol the water layers. Consequently, the rott- shallow water with many submerged trees and under fields of rvater hyacinth. At these lo- a sharp drop of temperature could be found in the first 5 metres(31" 28') and ing of the organic matter proceeded more rapidly than anticipated, as will be shown by cations also dropped sharply from 7-8 mg/I. to zero over the same depth interval. the observations orì oxygen content. Water hyacinth fields still occurred between the trees oxygen and in the southern part of the lake. The floating water fern Ceratopteris pteridoicles has been on a former occasion that the lake might be divided into a riverine zone, was no longerpresent so far as I could see, but bladderwort (.Utriculoriø sp.) and Jussieua It shown a transitional zone and a lake area as an expression of the effect of the Suriname River in notqns mtJsf be mentioned. Amongst the roots of water hyacinth many organisnìs were the lake and the related processes of self-purification. Apart from the physical and chemi- found, for example larvae of dragonflies, water bugs, water beetles, crustaceans, like C7- differences in the zones, the composition of the plankton is instructive. 'Ihe flowing wa- clestheriahislopiandshrirnps,andalsoyoungfish.Of theaquaticsnailsonlyafew Drepa- cal the Suriname River contained few specimens. Brown detritus was lairly abundant, notrema anatína were found locally. The lish in the lake were dominated by pireng (Ser- ter of together with spiculae of sponges, iron bacteria, and colonies of the flagellaTe Rhipidoden- rasalmo rhombeus) and the toekoenari (Cichlo ocellaris). both of which gave a good sport. dronhuxleyi. The plankton had a brown colour. Further to the north in the lake, where the water became stagnant, the plankton was less brown and most ol the spei:ies cf the po- At the fixed sal.npling stations in the lake, measurements on conductivity, temperature, tamoplankton were absent but there was a slight increase of zcoplanktort. On the next oxygen content and plankton were carried out. Thanks to the activity ol the Department stretch into the lake, the colour ofthe plankton turned to pale green, as algae such as Zoi- of Hydraulics in Surinam, regular monthly observations were made at the stations. which vox, Eudorina and Cosmørium became abundant. In this zone the water was supersaturated guaranteed a continuous piciure of the developments in the lake. During my stay in April with oxygen (transitional zone). Near to the middle of the lake large quantities of Cyclops 1968 I took samples at the stations in the lake and one in the affluent Surinam River near and Ceriodaphnia cornuta were present together with large numbers of Cosmorium spp. and Pokigron. The temperature of the water ranged lroni 16" near the bottom to 32o at the Eudorina elegans. Here the water was not supersaturated with oxygen. Further to the north, surlace; the conductivity ranged lrom l0 ¡lS at the surface to > 100 at the bottont near in the direction of the dam site, all these species decreased in nunrbers and the plankton the darn where the depth of the watel is greatest. pH ranged from 5.3 6.7. It appeared was composed mainiy of large quantities oldesmids, such as Staurostrum leptacanthum and that near the dani (Afobaka) free oxygen was present close to the bottont. On Apnl llth, other Staurastrum spp., Closterium spp., Cosmørium sp., Cosmocladiunt sp., Desmidium at Afbbaka 3 mg/I.O2 were present at 35 nretres; in the centre olthe lake at Kabel.7.3 sp., and Micrasterias spp. Crustacea, Rotifers, Volvox and Eudorina were less abundant. Ty- ng/1. at l5 nletres (bottom) and at station Sara, which is situated in a drownecl forest area. pical components of the plankton were the Ostracods, which generally live in shallow wa- the concentration was 5.2 mg/I. at 30 rnetres(bottom). The vertical distribution of the oxy- ter near the bottom. In conclusion, the plankton of the lake environment at this time was gen alternated with anaerobic layers. Therelore, at the stations of Afobaka ancl Sara the composed mainly of desmids, Crustaceans, Rotifers, Volvr¡x and Eudorina. Diatonis and vertical series ol ltìeasurenlents were made every two hours on one day. The results showed blue-green algae were virtually absent. The actual bloom ol desrnids and the decrease of tlrat by day the surfìce layels. lrorn 0 1.5 nletres, were always alrnost saturatecl with oxy- flagellates indicate that the water is less saprobic than in fbrmer years, which is in accold- gerl. [ìelow this clepth the oxygen content was very unstable. Total absence oloxygen al- ance with the data on oxygen content and oxygen consumption. As lar as I know, blooms terrlated wrth oxygen supersaturation witl'rin a few hours - even at the bottorn. In these of desmids are a rare phenomenon in great lakes and they indicate that a biological equi- saniples, living planktonic crustaceans were observed when oxygen was present and dead librium has not yet been established here, in spite olthe fact that there is a succession iu specilrlens if no oxygen was found. The cause olthe instability rriust be related in- to the plankton communities. As soon as the lake becornes equilibrated, it may be anticipated creasecl wind action on the open water. especially heavy alter showers and wincl, causing that no bloom of desrnids will appear. However the lake will remain as an oligotrophic abrupt and intensive ntixing of the water front dillerent areas. environment in which desmids will dominate.

The irrrproventent in the oxygen content of the deepel water layers inclicated that the nlineralization of the organic nlatter proceeded rapiclly. Laboratory tests with oxygen For further details on the deveiopment olpiankton in Lake Brokopondo, reference bottles lrade it cleal that in sanrples ol the superficial layer lronr about 5 nletres the oxy- may be made to the paper olJ.v.d. HEIDE at the S.l.L. - Congress in Leningrad, 1971. gen content alter three days in the dark renrained lairly constant, whereas those lronl thc and to my paper presented in May this year at the International Symposium on Man-made deeper layers were often depleted of,oxygen within three days. This dillerence in

I 3 Finally it should be mentioned that the research by the Brokopondo team was carried DUYFF, J.W., 1959: Nota betreffende de technisch-hygiè'nische problemen i.v.m. de uit- out under the auspicies ol the Foundation lor Scjentilic Research in Surinaln and the Neth- voering van het stuwmeerProject. erlands Antilles and firtanceci by the Netl.rerlands Foundation for the Aclvancement of Tro- J.v.d., 1966: Het stuwmeeronderzoek in Suriname. pical lìesearch. HEIDE, Trjdschr. Kon. Ned. Aardk. Gen.Òe reeks, deel 83,nr.2,p. 173 180

HOEDEMAN , J .J., 1962: Voor en tegen van het Brokopondo-stuwmeer. Elseviers Maandblad De Ke¡n, ian. 1962, p. 3 I -36 LEENTVAAR, P., 1965: De biologie van de Surinamerivier voor de gereedkoming van de ') Iì.1 N.-contntLrnjcation nr.40 Afobaka-stuwdanr. ' Schakels, S 60, p. 1-5

LEENTVAAR, P., 1965: De biologie van het Van Blommenstein-stuwmeer Schakels, S 60, p. 6 17

LEENTVAAR, P.. 1965: Iets over rivieren en kreken in Suriname. De Levende Natuur 68. p. D4- )32 Pubìications dealing with the Brokopondo-Project LEENTVAAR, P., 1965: Ervaringen in Suriname. Het Aquarium 36 (6), p. 126-132

P., The Brokopondo Lake Surinam. UOEShMAN, M., 1968: The Genus Hypostomus Lacépède, 1803, ancl its Surinarn represent- LEENTVAAR, 1966: in ativcs ( Silurilorntes, Loricariidae). Intern. Ass. of Theor. and Appl. Limn. l6 (6), p.680-685 Zool. Verhandl. 99. pp. 89 LEENTVAAR, P., 1966: The Brokopondo Research Project, Surinam. Man-Made Lakes, London, p. 33-42 BOtsStrMAN. M.. 1969: Additional new species olHypostornus Lacépêde, l803,lrom Su rittarlt. with re ntarks on the apparent 'gyrnnorhynchus-complex' (Siluriformes, Lorica- r-EENTVAAR , P., 1967 : The artificial Brokopondo Lake in the Suriname river. Its biolo- r, J tre ). gical implications. lleaufbrtia l6 (ll5). p. I l9-136 Atas Sympósio Biota Amazônica 3, Limnol. Brasil., p. 127 140 URtrEVEt.D. F., a.o., 197 I : Hvclro-nteteorologisch onclelzoek Brokopondr: S1,:wmeer. LEENTVAAR, P., 1968: Wetenschappelijk onderzoek op het stuwmeer IlvclraLrlic Research [)ivision. Ministry ol Prrblic works and rralfic. Suriname. BauxcoNieuwsT,p.4 7 DEN4OLI LlN. (i . l9(r6: ('orrtribution iì l'étudc des trphénréroptdres du Surinani. P., 1911 : Lake Brokopondo. l;ull. Irrst. Sci. Nat. Belg.4l (37). pp ìl LEENTVAAR , Proc. Int. Symp. on Man-Made Lakes, Knoxville, U.S.A. (in press) l)ONStrt.¡\AR. J v . l9(r8: Water attcl nrarsll plants in the artificìal Blokoponclo Lake (Su LOON, U.J.v., i970: Hydrological data Suriname River. rinanr. S. Anrcrica)during thc f irst tlrree years of its existence. Hydraulic Research Division, Ministry of fublic Works and Traffic, Suriname ì!f e'tl . lìrt. Mus. en flerb R Ll Lltrecht 199. p. l8-3 196 lX)\5l l A^R J v. & WLSI RA. I Y l'1t.. l()rrS: Dc epiplrl tt'rrtuirrtjes vrrr hcl Brokopon. LOWE-McCONNELL, R.H., 1966: Man-Made Lakes. (l()-SluWnìeùt. Inst. Biol.; Ac. Press. London-New York, 218 pp. Orchideèèn -10 (l). p -36 ;1I McCONNELL, R.L. & WORTHINGTON, 8.8., 1965: Man-Made Lakes. tX)NSllLAAR. J v . l9(r9: On thc Distributiort ant.l Ecology olCeratopter.is in Surinam. Nature 208 (5015), p. 1039 1042 Anl. fìern Journ. 59 (l). p. -] 8

4 5 MEMORANDUM inzake Natuurbehee¡ in Suriname, 1970: WESTERMANN, J.H., 1956: Een korte beschouwing over het Brokopondoplan Surinarne Stinasu verhandeling 1,46 pp. Nat. Wet. Studiekring voor Suriname en cle Ned. Antillen, Utrecht, pp. l6

NOELMANS, P.L.J., 1969: Oecologie en verspreiding van enkele zeldzame fauna-eiemen WESTERMANN, J.H., 197 1: Historisch overzicht van de wording en het onderzoek van ten in Suriname. het Brokopondo-stuwmeer. Ingen ieursscriptie Wagen ingen De Nieuwe West-Indische Gids 48 ( l), april. NIJSSEN-MEYER, J., 1967: Rapport Hydrobiologie Suriname. Onderzoek Van Blomme- stein-stuwmeer. 1. I-1. VII, 7 pp. + brjlagen (unpubiished)

NIJSSEN, H. & ISBRÜCKER, I.J.H., 1968: Gymnotus carapo and G. anguillaris (syn.: G. coropinae), two often confused species of gymnotid fishes (Pisces, Cypriniformes). Beaufortia 15, p. 161 168

NIJSSEN, H., 1970: Revision of the Surinam Catfishes of the genus Corydoras Lacépêde, I 803 (Pisces, Siluriformes, Callichthyidae). Summary Proefschrift Universiteit van Amsterdam, 1970

PRAEADVIES inzake het Streekplan Brokopondo. After the closing of the dam in the Suriname River in 1964, the changes in the environ- Bureau Landelijke Opbouw Paramaribo., april 1960 ment and plant and animal life were followed continuously during three years. Several pu- biications about the vegetation, fish fauna and hydrobiology from different investigators PROGRESS REPORTS of the Biological Brokopondo Research Project, Surinanr 1964 appeared. 1969 Part I, 1963- 1964, p. l-89 In 1968 the author revisited the lake for some weeks and the hydrobiological observa Part II, 1965 , p.90-141 tions in that period are given here, in addition to the data given at the lVl--Congress in Part III, 1965-1966, p. 142 201 1965 (see: IVL-Handl. 16,1966). Part IV, 1967 1969,p.208 265 Foundation for Scientific Research in Surinam and the Netherlands Antilles In May 1968 the water gauge was23l ft. In August \961 the mark of 241 fl.. was reached RINGMA, S.h., 1952, 1953: Combinatieplan Suriname Rivier and the work was ready for use. An estimated 40 % of the lake was covered by water-

Hydrologische Nota nr. 4 and 5 . hyacinth (Eichhornia crøssipes). The plants were controlled by sprayin g 2 - 4 D , from aero- the water-hyacinth is practically ab- SCHULZ, J .P., 1954 Vergelijkend literatuuronderzoek inzake de ecologische consequen- plane and boats. Information from 1970 reports that ties van het'Combinatieplan Surinamerivier'. sent now. Nat. Wet. Stud. v. Suriname en de Ned. Antillen, Utrecht, 124 pp. As a result of the drowning of trees and the disappearance of water-hyacinth the effect WAGENAAR HUMMELINCK, P., 1961 : 'Het Brokopondoplan' of wind on the water has ìncreased. This caused currents and mixing of the lake water. Vakblad voor Biologen, sept., p. 174 179 Oxygen was found even at the bottom at a depth of 35 m. The verticai distribution of WALSH, J. & CANNON, R., 1967: Time is short and the water rises. Operation Gwamba oxygen was irregular and changed rapidly at all depths during the day. In sheltered stations New York. E.P. Dutron & Co.. lnc.. pp. )24 oxygen remained low and was absent below 5 meter. The observations in 1968 point to an of the oxygen content in the lake ; the information from 1970 however in- WEERT, R.v.d. & KAMERLING, G.8., 1967: Evapotranspiratie van waterhyacinth. improvement that no further ptogress is made, probabiy as a result of the large amounts of decay- Intern Rapport 21 1, Landbouwproefstation, Paramaribo, pp. 49 dicates ing water-hyacinths, which must be present near the bottom by the radical control.

6 7 Fish developed well in the lake but there are few species, represented by Cichla IV I 9-102 Kiel, März 1973 o c e llar is and S errasa lmo r ho mb eus. AMAZONIANA

The pH at different stations ranged from 5.5 to 6.4 with the highest value at the surface. Conductivity ranged from 20 to 40 ¡.rS at the surface and increased to the bottom. In (From: Cooperation between Max-Planck-Institut für Limnologie, Abt. Tropenökologie, this environment Desmids develop in great numbers; diatoms and blue-algae were scarce; Plön, Germany, and Instituto Nacional de Pesquisas da Amazônia, Manaus-Amazonas, plankton crustaceans and rotifers were present in great numbers. Compared to former Brazil) years, the rich development. of Volvox and Eudorína was decreasing.

Investigations on the Ecology and Production-Biology of the_"Floating Meadows" (Paspalo-Echinochloetum) on the Middle Amazonl)

Part II. The Aquatic Fauna in the Root Zote of Floating Vegetation

by WOLFGANG J. JUNK, Max-Planck-Institute for Limnology, Department Tropical Eco- logy, Plön, Germany

l) Brazilian Contribution ol the lnternational Biological Programme, Section PFM; Con- tribuição brasileira ao Programa Biológico Internacional, Secção PFM.

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