The spatial and temporal dynamics of phytoplankton community and their correlation with environmental factors in Wuliangsuhai Lake, China

Abstract

The principal environmental factors influencing the monthly dynamics of phytoplankton were examined from April to October in 2016 in 12 stations of Lake Wuliangsuhai (northwest China). Interestingly, in this lake, nutrient did not exhibit to be limiting for the phytoplankton growth. From April to October, the volume of total nitrogen (TN) range 0.66~22.22 mg/L, maximum volume was in W1 station in October; total phosphorus (TP) range 0.008~0.339 mg/L, maximum volume was in W2 station in April; NH4–N range 0.11~1.74mg/L, maximum volume was in W12 station in October. The most critical forcing factors were water quality physicochemical parameter variables, mainly water temperature (WT), salinity (Sal), conductivity (CON), total dissolved solids (TDS), pondus hydrogenii (pH), and water transparency (SD). The highest phytoplankton density (2.99 × 108 cells/L) was recorded in station W12 in June, and the lowest phytoplankton density (4.84 × 105 cells/L) in station W8 in May, in conditions of increasing water temperature in summer and lower water temperature in spring. Conversely, the highest species number (61 species) exhibited in station W5 in September, and the lowest species number (6 species) exhibited in station W1 in May. The physicochemical parameter variables, mainly WT, Sal, CON, TDS, pH, and SD, had a significant and measurable effect not only on the development of phytoplankton density but also on the monthly dynamics of the phytoplankton community. Our results revealed that the species number and density of the phytoplankton could serve as biological water quality indicators, which would give overall descriptions of water quality in Wuliangsuhai Lake.