High nutrient loading and climatic parameters influence the dominance and dissimilarity of toxigenic cyanobacteria in northern bays of Lake Victoria

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dc.contributor.authorOlokotum, Mark
dc.contributor.authorTroussellier, Marc
dc.contributor.authorEscalas, Arthur
dc.contributor.authorHamlaoui, Sahima
dc.contributor.authorOkello, William
dc.contributor.authorSemyalo, Ronald
dc.contributor.authorHumbert, Jean-François
dc.contributor.authorBernard, Cécile
dc.date.accessioned2023-01-10T08:39:02Z
dc.date.available2023-01-10T08:39:02Z
dc.date.issued2021
dc.description.abstractEutrophication of Lake Victoria led to changes in its phytoplankton communities. However, different levels of eutrophication exist in the open lake and the bays, and between embayments. This study utilized spatial and temporal sampling of Napoleon Gulf and Murchison Bay, exhibiting different trophic conditions. Over one year, we investigated phytoplankton biomass, richness, diversity and dissimilarity, and related the dynamics of the dominant species to the limnological and climatic conditions. The results confirmed that Napoleon Gulf and Murchison Bay showed large differences in eutrophication status, with lower nutrient concentrations in Napoleon Gulf than in Murchison Bay, where a strong gradient was observed from inshore to offshore areas. These nutrient dynamics resulted in a 4 to 10 fold higher chlorophyll-a in Murchison Bay than in Napoleon Gulf. From the embayments, 135 phytoplankton taxa were recorded with no significant differences in alpha diversity. However, high dissimilarity in community structure was observed in beta diversity, mostly due to a turnover among the dominant toxigenic species. Thus, from a similar species pool, there was a shift in the dominant toxigenic cyanobacteria from Microcystis flos-aquae and M. aeruginosa in Murchison Bay, Dolichospermum circinale and Planktolyngbya circumcreta in Napoleon Gulf to D. circinale in the offshore stations. These cyanobacteria are toxigenic taxa with known health hazards. Using partial least square models, we showed that both climatic variables (e.g. wind, solar radiation) and levels of inorganic dissolved nutrients (e.g. SRP, NO3 – , and NH4 + ) are the main drivers of differences and dominance in cyanobacteria communities in northern Lake Victoria.en_US
dc.identifier.citationOlokotum, M., Troussellier, M., Escalas, A., Hamlaoui, S., Okello, W., Semyalo, R., ... & Bernard, C. (2021). High nutrient loading and climatic parameters influence the dominance and dissimilarity of toxigenic cyanobacteria in northern bays of Lake Victoria. Journal of Great Lakes Research, 47(4), 985-996. https://doi.org/10.1016/j.jglr.2021.04.021en_US
dc.identifier.urihttps://doi.org/10.1016/j.jglr.2021.04.021
dc.identifier.urihttps://nru.uncst.go.ug/handle/123456789/6857
dc.language.isoenen_US
dc.publisherJournal of Great Lakes Researchen_US
dc.subjectEutrophicationen_US
dc.subjectLake Victoriaen_US
dc.subjectCyanobacteriaen_US
dc.subjectPhytoplanktonen_US
dc.subjectDiversityen_US
dc.subjectBays and gulfsen_US
dc.titleHigh nutrient loading and climatic parameters influence the dominance and dissimilarity of toxigenic cyanobacteria in northern bays of Lake Victoriaen_US
dc.typeArticleen_US
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