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Nutrient dynamics and turnover rates of phosphate and sulfate in Lake Victoria, East Africa
Author(s) -
Lehman John T.,
Branstrator Dorm K.
Publication year - 1994
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1994.39.2.0227
Subject(s) - sulfate , nutrient , phytoplankton , environmental science , phosphate , water column , environmental chemistry , plankton , biomass (ecology) , productivity , sediment , oceanography , hydrology (agriculture) , chemistry , ecology , geology , biology , geotechnical engineering , macroeconomics , organic chemistry , economics , paleontology
The dominant process removing sulfate from the water of Lake Victoria is biological uptake by plankton >1 µ m in size. Uptake of sulfate in the water column is substantially greater than uptake at the sediment surface. Despite low ambient concentrations (3–4 µ M), rates of uptake of sulfate by phytoplankton do not increase when additional sulfate is added to the water, and ambient concentrations are adequate to support maximum uptake rates. Uptake rates for phosphate are similarly near‐maximal in offshore waters. Furthermore, experimental addition of sulfate or phosphate fails to increase biomass production over control levels, but addition of N alone or in combination with P and S does increase algal biomass. Although sulfate concentrations in Lake Victoria are lower than values reported for any large lake worldwide, our results indicate that sulfate behaves as a nonlimiting nutrient in Lake Victoria and that it does not limit the primary productivity of the lake.