Variation of community structure of phytoplankton and metazoan zooplankton associated with a Microcystis bloom.

Globally, blooms of Microcystis and other cyanobacteria lead to impairment in lake ecosystems. Co-occurring plankton is recognized as one of the most sensitive targets negatively influenced by Microcystis blooms. However, our understanding of how co-occurring plankton communities are impacted by blooms is limited. To assess bloom impact, we investigated the spatial-temporal variation of the plankton community in Lake Dianchi, the largest lake in southwest China and which has been stressed by recurring blooms of Microcystis. We found that Microcystis were dominant amongst cyanobacteria whereas chlorophytes and diatoms were most abundant amongst eukaryotic phytoplankton. Rotifers and small-body cladocerans were dominant among metazoan zooplankton in summer (blooming season) whereas large-body cladocerans were dominant in winter (lower Microcystis density). The composition of the phytoplankton and metazoan zooplankton communities relied significantly on Microcystis abundance, especially in summer. Furthermore, variables of Microcystis relative biomass explained the highest variation of phyto-, metazoan zooplankton communities in both summer (27%) and winter (36%). Among all phyto-, metazoan zooplankton taxa, Microcystis abundance was correlated strongly to abundance of chlorophytes and cladocerans. Our study enhances the understanding of the influence of Microcystis blooms on plankton communities, knowledge that will inform lake management strategies. [ABSTRACT FROM AUTHOR]