Spatio-temporal variations of phytoplankton community composition assayed by morphological observation and photosynthetic pigment analyses in Lake Taihu (China)

Abstract

Spatio-temporal variations of phytoplankton were assayed by morphological observation and photosynthetic pigment analyses at four sites in Lake Taihu from September 2007 to June 2008. Results showed that cyanobacteria abundance in water column decreased from autumn to winter but increased
in the sediment; in spring, cyanobacteria abundance decreased in sediment but increased in water column. Since phycocyanin in the sediment fluctuated during the year with maxima in March and minima in September, vertical migration and recruitment of cyanobacteria were apparent. Algal
abundance and composition changed in the water column. Chlorophytes dominated phytoplankton community initially and were replaced by cyanobacteria especially Microcystis spp., which underwent a colony-enlargement process and evolved from colonies with a few cells to those with dozens or hundreds of cells before blooming in late June.