Seasonal variation of phytoplankton in the DaNing River and its relationships with environmental factors after impounding of the Three Gorges Reservoir: A four-year study

The aim of this study was to understand the seasonal succession of phytoplankton composition and the mechanism of algae bloom formation in the DaNing River after impounding of the Three Gorges Reservoir. A relatively long-term dataset of biotic and abiotic parameters of water quality in the river was subjected to correlation analysis and redundancy analysis (RDA). The results indicate that water temperature and TN/TP (total nitrogen divided by total phosphates) are key regulatory factors for phytoplankton abundance. The results of the correlation analysis and RDA suggest that temperature is a key regulatory factor for phytoplankton community composition and algae-bloom dominance in flood season; TN/TP and TN play governing roles in phytoplankton dynamics during the normal season; and transparency, TP and dissolved oxygen contributed significantly to phytoplankton community composition during the dry season.