Temporal and spatial variations in phytoplankton: correlations with environmental factors in Shengjin Lake, China

Temporal and spatial variations in the phytoplankton community and environmental variables were investigated from February to July 2014, in the upper lake of Shengjin Lake, China. We identified 192 species of phytoplankton belonging to 8 phyla and 84 genera, of which 46.4% of Chlorophyta, 29.2% of Bacillariophyta, and 12.5% of Cyanophyta. There were 14 predominant species. Marked temporal and spatial variations were observed in the phytoplankton community. The total abundance of phytoplankton ranged from 3.66 × 10(5) to 867.93 × 10(5) cells/L and total biomass ranging from 0.40 to 20.89 mg/L. The Shannon-Wiener diversity index varied from 3.50 to 8.35 with an average of 5.58, revealing high biodiversity in the phytoplankton community. There were substantial temporal changes in the dominant species, from Bacillariophyta and Cryptophyta to Cyanophyta and Chlorophyta. Phytoplankton biomass and abundance showed a similar increasing trend from February to July. Pearson correlations and Redundancy analysis revealed that the most significant environmental factors influencing phytoplankton community were water temperature (T), transparency (SD), and nutrient concentration. The positive correlation between the key water bird areas and phytoplankton biomass indicated that the droppings of wintering water birds had an important influence on the phytoplankton community in the upper lake of Shengjin Lake.