Correlation Analysis of Spring Phytoplankton Community and Environmental Factors in Hazihu Lake

Community structure of phytoplankton and the associated environmental factors were investigated in Haizihu,Changhu Lake in the spring of 2012,and their relationship was also analyzed by canonical correspondence analysis( CCA). Results showed that 93 species of phytoplankton were identified,among which Chlorophyta accounted for 46. 76%,followed by Bacillariophyta( 22. 65%) and Cyanophyta( 15. 00%). There were 6 dominant species and the most dominant species was Chlorella vulgaris with the dominance index of 0. 36. The phytoplankton abundance ranged from 86. 21 × 105to 410. 12 × 105cells / L with the average value of 232. 85 × 105cells / L. Biodiversity index and evenness index were 1. 82- 3. 28 and 0. 40- 0. 63,respectively. As a result,the water in Haizihu was in a state of severe eutrophication according to the level of phytoplankton abundance,as well as the degree of dominance and the diversity index. Canonical correlation analysis( CCA) suggested that NO3-N,COD,Chl. a, PO4-P were the main environmental factors which affected the spatial distribution of phytoplankton community, meanwhile,geographical feature,human activities and hydrodynamic features were also the important influencing factors.