Phytoplankton of Lake Kivu

Hugo Preto de Morais Sarmento, François Darchambeau, Jean-Pierre Descy

Résultats de recherche: Contribution dans un livre/un catalogue/un rapport/dans les actes d'une conférenceChapitre (revu par des pairs)


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 Fragi-laria danica are dominant. Important seasonal shifts occur, with cy-anobacteria 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 as-semblage was quasi homogeneous among lake basins. The mean eu-photic depth varied between 17 and 20 m, and the increase in the ra-tio between mixed layer depth : euphotic depth to about 2 in the dry season may have selected for diatoms and cryptophytes, which tend-ed to present their maximal development in this season, when cya-nobacteria slightly decreased. Mean chlorophyll a concentration was 2.03 – 2.24 depending on the lake basin, and the mean daily primary production was 0.62 g C m-2 d-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, strat-ified 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, phyto-plankton ecology in Lake Kivu does not differ from that of other Rift lakes, where seasonal variations result in a trade-off between low light-high nutrient supply and high light-low nutrient supply. Phytoplankton production in Lake Kivu is also similar to that of oth-er Rift lakes, and nutrient limitation of phytoplankton growth may occur as a result of variable availability of N and P, as in Lakes Tan-ganyika and Malawi, even though the extent of P limitation seems greater in Lake Kivu.
langue originaleAnglais
titreLake Kivu: Limnology and biogeochemistry of a tropical great lake
rédacteurs en chefJean-Pierre Descy, François Darchambeau, Martin Schmid
Les DOIs
Etat de la publicationPublié - 2012

Série de publications

NomAquatic Ecology Series

Empreinte digitale Examiner les sujets de recherche de « Phytoplankton of Lake Kivu ». Ensemble, ils forment une empreinte digitale unique.

Contient cette citation