Dianshan Lake, a subtropical shallow lake, is one of the main drinking water sources of Shanghai City. In order to explore the characteristics of phytoplankton functional groups (PFGs) and their relationships with environmental factors in Dianshan Lake, phytoplankton and water samples collected from January 2015 to December 2016 were characterized. Results suggested that there were 26 PFGs during our study period. The biomasses of 15 PFGs (B, C, D, F, G, H1, J, Lo, M, MP, P, W1, W2, X1, and X2) were dominant and had marked annual succession patterns: D/C Lo/C/MP MP/J/P/W1 P in 2015 and P W2/Lo W2/G/M/H1 P in 2016. To elucidate the relationships of PFGs with the environmental factors, canonical correspondence analysis (CCA) was conducted. Results showed that water level fluctuation (WLF), dissolved oxygen (DO), water temperature (WT), total phosphorus (TP), electrical conductivity (EC), transparency (SD), and total nitrogen (TN) were the main impact factors associated with the composition variations of PFGs in Dianshan Lake. From this study, it is proposed that the effects of nitrogen, phosphorus, and WLF on the PFGs in Dianshan Lake should be paid more attention.
Keywords: Dianshan Lake; environmental factor; functional groups; phytoplankton; succession characteristics.