Studies on the Community Structure of Phytoplankton and Eutrophication Characteristic of Mingcui Lake

Based on the data in Mingcui Lake from Sep.2008 to Jul.2009,the species composition,phytoplankton density,phytoplankton biomass,seasonal variation,dominate species of phytoplankton and the trophic status of Mingcui Lake were discussed.8 phyla,61 genera,118 species of phytoplankton community in Mingcui Lake were identified.The proportion of community composition was Chlorophyta 42.4%,Cyanophyta 21.2%,Bacillariophyta 18.6%,and others 17.7%.The dominant species were some species of Cyanophyta.The composition and distribution of phytoplankton in Mingcui Lake was different according to the variation of seasons.The seasonal variation of phytoplankton in Mingcui Lake was that the highest peaks appeared in July,and the lowest peaks appeared in May.Margalef index was 1.267～2.942,Shannon-Wiener index was 2.459～4.098,evenness index was 1.782～2.605.The water body of Mingcui Lake was medium eutrophication.