[en] This chapter reviews taxonomic composition, biomass, production and nutrient limitation of the phytoplankton of Lake Kivu. Present Lake Kivu phytoplankton is dominated by cyanobacteria – mainly Synechococcus spp. and thin filaments of Planktolyngbya limnetica – and by pennate diatoms, among which Nitzschia bacata and Fragilaria danica are dominant. Seasonal shifts occur, with cyanobacteria developing more in the rainy season, and the diatoms in the dry season. Other groups present are cryptophytes, chrysophytes, chlorophytes and dinoflagellates. According to a survey conducted in the period 2002–2008, the composition of the phytoplankton assemblage was quasi homogeneous among lake basins. The mean euphotic depth varied between 17 and 20 m, and the increase in the ratio between mixed layer depth and euphotic depth to about 2 in the dry season may have selected for diatoms and cryptophytes, which tended to present their maximal development in this season, when cyanobacteria slightly decreased. Mean chlorophyll a concentration was 2.16 mg m−3, and the mean daily primary production was 0.62 g C m−2 day−1 (range, 0.14–1.92), i.e. in the same range as in other large oligotrophic East African Rift lakes. Seston elemental ratios indicated a moderate P deficiency during the dry, mixed season and a severe P limitation during part of the rainy, stratified season; the C:N ratio indicated a moderate N limitation throughout the year. Nutrient addition assays pointed to a direct N limitation and co-limitation by P during rainy seasons and P or N limitation during dry seasons depending on the year. Thus, phytoplankton ecology in Lake Kivu does not differ from that of other Rift lakes, where seasonal variations result in a trade-off between low light with high nutrient supply and high light with low nutrient supply. Phytoplankton production in Lake Kivu is also similar to that of other Rift lakes, and nutrient limitation of phytoplankton growth may occur as a result of variable availability of N and P, as in Lakes Tanganyika and Malawi, even though the extent of P limitation seems greater in Lake Kivu.
Disciplines :
Aquatic sciences & oceanology
Author, co-author :
Sarmento, Hugo; Institut de Ciències del Mar, Barcelona - Spain
Darchambeau, François ; Université de Liège - ULiège > Département d'astrophys., géophysique et océanographie (AGO) > Unité d'Océanographie chimique (UOC)
Lake Kivu, Limnology and Biogeochemistry of a Tropical Great Lake
Editor :
Descy, Jean-Pierre
Darchambeau, François ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO) > Chemical Oceanography Unit (COU)
Beadle LC (1981) The inland waters of tropical Africa - an introduction to tropical limnology. Longman, New York
Bergamino N, Horion S, Stenuite S, Cornet Y, Loiselle S, Plisnier PD, Descy JP (2010) Spatiotemporal dynamics of phytoplankton and primary production in Lake Tanganyika using a MODIS based bio-optical time series. Remote Sens Environ 114:772-780. doi:10.1016/j. rse.2009.11.013
Damas H (1935-1936) Exploration du Parc National Albert. Institut des Parcs Nationaux du Congo Belge, Liège, Belgium
Damas H (1937) Quelques caractères écologiques de trois lacs équatoriaux: Kivu, Edouard, Ndalaga. Ann Soc R Zool Belg 68:121-135
Degens E, Herzen RP, Wong H-K, Deuser WG, Jannasch HW (1973) Lake Kivu: structure, chemistry and biology of an East African Rift lake. Geol Rundsch 62:245-277. doi:10.1007/BF01826830
Descy J-P (1990) Etude de la production planctonique au lac Kivu - Rapport de mission, Projet PNUD/FAO RWA/87/012. UNECED, Namur
Descy J-P, Hardy M-A, Stenuite S, Pirlot S, Leporcq B, Kimirei I, Sekadende B, Mwaitega S, Sinyenza D (2005) Phytoplankton pigments and community composition in Lake Tanganyika. Freshw Biol 50:668-684. doi:10.1111/j.1365-2427.2005.01358.x
Frémy P, Pascher A, Conrad W (1949) Exploration du Parc National Albert - Mission H. Damas (1935-1936), Fascicule 19: Algues et Flagellates. Institut des Parcs Nationaux du Congo Belge, Bruxelles, Belgium
Guildford SJ, Bootsma HA, Taylor WD, Hecky RE (2007) High variability of phytoplankton photosynthesis in response to environmental forcing in oligotrophic Lake Malawi/Nyasa. J Gt Lakes Res 33:170-185. doi:10.3394/0380-1330(2007)33[170:HV0PPI]2.0.C0;2
Guildford SJ, Hecky RE (2000) Total nitrogen, total phosphorus, and nutrient limitation in lakes and oceans: Is there a common relationship? Limnol Oceanogr 45:1213-1223. doi:10.4319/lo.2000.45.6.1213
Haberyan KA, Hecky RE (1987) The late pleistocene and holocene stratigraphy and paleolimnology of Lakes Kivu and Tanganyika. Paleogeogr Paleoclimatol Paleoecol 61:169-197. doi: 10.1016/0031-0182(87)90048-4
Healey FP, Hendzel LL (1980) Physiological indicators of nutrient deficiency in lake phytoplankton. Can J Fish Aquat Sci 37:442-453. doi:10.1139/f80-058
Hecky RE, Kling HJ (1987) Phytoplankton ecology of the great lakes in the rift valleys of Central Africa. Arch Hydrobiol Beih Ergeb Limnol 25:197-228
Hustedt F (1949) Exploration du Parc National Albert - Mission H. Damas (1935-1936), Fascicule 8: Süsswasser-Diatomeen. Institut des Parcs Nationaux du Congo Belge, Bruxelles, Belgium
Isumbisho M (2006) Zooplankton ecology of Lake Kivu (eastern Africa). PhD thesis, University of Namur, Belgium
Isumbisho M, Sarmento H, Kaningini B, Micha JC, Descy JP (2006) Zooplankton of Lake Kivu, East Africa, half a century after the Tanganyika sardine introduction. J Plankton Res 28:971989. doi:10.1093/plankt/fbl032
Jannasch HW (1975) Methane oxidation in Lake Kivu (central Africa). Limnol Oceanogr 20:860-864
Kilham P, Kilham SS, Hecky RE (1986) Hypothesized resource relationships among African planktonic diatoms. Limnol Oceanogr 31:1169-1181
Kilham SS, Kilham P (1990) Endless summer: internal loading processes dominate nutrient cycling in tropical lakes. Freshw Biol 23:379-389. doi:10.1111/j.1365-2427.1990.tb00280.x
Kling H, Mugidde R, Hecky RE (2001) Recent changes in the phytoplankton community of Lake Victoria in response to eutrophication. In: Munawar M, Hecky RE (eds) The great lakes of the world (GLOW): food-web, health and integrity. Backhuys Publishers, Leiden, The Netherlands
Mugidde R (1993) Changes in phytoplankton primary productivity and biomass in Lake Victoria (Uganda). Verh Int Ver Theor Angew Limnol 25:846-849
Mukankomeje R, Plisnier PD, Descy JP, Massaut L (1993) Lake Muzahi, Rwanda - limnological features and phytoplankton production. Hydrobiologia 257:107-120. doi: 10.1007/BF00005951
Reynolds CS (2006) The ecology of phytoplankton. Cambridge University Press, Cambridge
Sarmento H (2006) Phytoplankton ecology of Lake Kivu (eastern Africa). PhD thesis, University of Namur, Belgium
Sarmento H, Isumbisho M, Descy JP (2006) Phytoplankton ecology of Lake Kivu (eastern Africa). J Plankton Res 28:815-829. doi:10.1093/plankt/fbl017
Sarmento H, Isumbisho M, Stenuite S, Darchambeau F, Leporcq B, Descy JP (2009) Phytoplankton ecology of Lake Kivu (eastern Africa): biomass, production and elemental ratios. Proc Int Assoc Theor Appl Limnol 30:709-713
Sarmento H, Leitao M, Stoyneva M, Couté A, Compère P, Isumbisho M, Descy JP (2007) Diversity of pelagic algae of Lake Kivu (East Africa). Cryptogam Algol 28:245-269
Sarmento H, Unrein F, Isumbisho M, Stenuite S, Gasol JM, Descy JP (2008) Abundance and distribution of picoplankton in tropical, oligotrophic Lake Kivu, eastern Africa. Freshw Biol 53:756-771. doi:10.1111/j.l365-2427.2007.01939.x
Sarvala J, Salonen K, Jarvinen M, Aro E, Huttula T, Kotilainen P, Kurki H, Langenberg V, Mannini P, Peltonen A, Plisnier PD, Vuorinen I, Molsa H, Lindqvist OV (1999) Trophic structure of Lake Tanganyika: carbon flows in the pelagic food web. Hydrobiologia 407:149-173. doi: 10.1023/A: 1003753918055
Silsbe GM (2004) Phytoplankton production in Lake Victoria, East Africa. MSc thesis, Univ. of Waterloo, Canada
Silsbe GM, Hecky RE, Guildford SJ, Mugidde R (2006) Variability of chlorophyll a and photosynthetic parameters in a nutrient-saturated tropical great lake. Limnol Oceanogr 51:2052-2063. doi:10.4319/lo.2006.51.5.2052
Spamer EE, Theriot EC (1997) Stephanodiscus minutulus, S. minutus, and similar epithets in taxonomic, ecological, and evolutionary studies of modern and fossil diatoms (Bacillariophyceae: Thalassiosiraceae) - a century and a half of uncertain taxonomy and nomenclatural hearsay. Proc Acad Nat Sci Phila 148:231-272
Stenuite S, Pirlot S, Hardy MA, Sarmento H, Tarbe AL, Leporcq B, Descy JP (2007) Phytoplankton production and growth rate in Lake Tanganyika: evidence of a decline in primary productivity in recent decades. Freshw Biol 52:2226-2239. doi:10.1111/j.1365-2427.2007.01829.x
Van Meel L (1954) Le Phytoplancton. Résultats Scientifiques de l’Exploration Hydrobiologique du Lac Tanganyika. Institut Royal des Sciences Naturelles de Belgique, Bruxelles, Belgium
