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Variability of chlorophyll a and photosynthetic parameters in a nutrient‐saturated tropical great lake
Author(s) -
Silsbe G. M.,
Hecky R. E.,
Guildford S. J.,
Mugidde R.
Publication year - 2006
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.2006.51.5.2052
Subject(s) - eutrophication , bay , irradiance , environmental science , chlorophyll a , phytoplankton , water column , oceanography , advection , atmospheric sciences , nutrient , bloom , ecology , geology , biology , botany , physics , quantum mechanics , thermodynamics
Diurnal measurements of Secchi depth, light attenuation, thermal structure, photosynthetic irradiance (PE) parameters, and chlorophyll a (Chl a ) were performed at weekly intervals in three inshore bays in Lake Victoria, Uganda. The only statistically significant diurnal patterns observed were a decline in PE parameters normalized to Chl a and a decline in gross integral phytoplankton production. On a weekly timescale, Chl a was positively correlated to changes in the mean water‐column temperature (T WC ) in each bay. Meteorologic data in one of these bays suggest that the synchronous increases and decreases in Chl a and T WC are related to the extent of advective exchange with deeper areas of the lake. Analysis of all data from this study, as well as available historic data, reveals that the optical properties of Lake Victoria covary with the concentration of Chl a . On weekly timescales, the PE parameters α B and P BM covary, and both parameters generally decline as Chl a increases, a pattern consistent with historic data from Lake Victoria. Empirical relations are developed that relate optical properties and PE parameters to Chl a . These relations provide a mathematical representation of the limnologic changes that Lake Victoria has experienced through eutrophication and can be used to predict these parameters over larger spatial and temporal scales and facilitate estimates of whole‐lake primary production.