Phytoplankton community structure in Wuliangsuhai Lake and its relationships with environmental factors using Canonical Correspondence Analysis

An investigation was conducted on the phytoplankton community structure from May to August in 2012,in order to analysis temporal and spatial variation of phytoplankton composition,density,biomass and diversity indices and its relationships with environmental factors by Canonical Correspondence Analysis.Results showed that Chlorophyta,Bacillariophyta and Cyanophyta accounted for 49%,23%,14% of all the species,respectively.In May,the highest phytoplankton density and biomass was 52.65×106ind L-1,43.40 mg L-1,respectively.The lowest phytoplankton density was 15.81×106ind L-1in August.The lowest phytoplankton biomass was 20.0 mg L-1 in June.Variability was the same for the indices of Margalef and Shannon-Wiener,the lowest value was 1.52,2.25 in May,respectively,the highest value was 2.85,2.80 in August,respectively.The highest indices of Pielou was 0.64 in July.The temporal and spatial variability of phytoplankton density and biomass was significant,the temporal variation of the indices of Margalef and Shannon-Wiener was significant.The succession of phytoplankton community was Bacillariophyta-Chlorophyta-Cyanophyta,Chlorophyta-Cyanophyt-Bacillariophyta,Cyanophyta-Chlorophyta-Bacillariophyta.Canonical Correspondence Analysis(CCA) showed that total nitrogen,electrical conductivity,salinity,total dissolved solid,dissolved oxygen were the main environmental factors affecting the phytoplankton community structure in the Wuliangsuhai Lake in spring and summer and most of the Cyanophyta was a great demand for total phosphorus and most of the Chlorophyta and Bacillariophyta was a great demand for nitrate nitrogen.