Horizontal distribution of the cell abundance and toxicity of Microcystis in a hypereutrophic Moroccan reservoir

The first results of the horizontal distribution of the cell abundance and toxicity of Microcystis in the hypereutrophic Moroccan reservoir Lalla Takerkoust are reported. An unexpected spatio-temporal heterogeneity has been shown between Microcystis abundance and microcystins concentrations. The principal determining factors were analyzed in order to identify the most likely sites for the proliferation and/or accumulation of Microcystis in this reservoir. The horizontal heterogeneity seems to be mainly influenced by the wind direction and inflows. The results can serve as reference data for monitoring cyanobacterial water blooms and associated cyanotoxins in the lake.