Seasonal Succession of Phytoplankton Functional Groups and Their Driving Factors in the Siminghu Reservoir

Abstract

The succession of phytoplankton communities is affected by pure environmental factors as well as the interaction of various factors. Phytoplankton communities with eleven aquatic abiotic factors and four biotic factors were investigated in the Siminghu Reservoir, and the seasonal succession of phytoplankton FGs related to the biotic and abiotic factors was analyzed. The results suggested that a total of 22 phytoplankton functional groups were identified across the samples, and they were all affiliated with Chlorophyta and Bacillariophyta. An obvious seasonal succession was discovered by NMDS, which were present as D+Lo in summer, D+P+Lo in autumn and winter, and X2+P+MP in spring. In particular, we screened 10 functional groups with biomass significantly associated with the seasonal change in the phytoplankton community. A variance partitioning analysis (VPA) revealed that water temperature-zooplankton covariation and water temperature explained the variation in the phytoplankton functional groups throughout the year. A canonical correspondence analysis (CCA) showed that water temperature, transparency, nitrate nitrogen, and the biomass of zooplankton were the most critical factors determining the community dynamics of phytoplankton.