巢湖及其支流浮游动物群落结构特征及水质评价

2013年9月至2014年6月对巢湖及柘皋河、杭埠河、南淝河3条支流的浮游动物进行了调查,共检出浮游动物297种,其中,原生动物124种,轮虫135种,枝角类29种,桡足类9种。南淝河浮游动物物种数最多,为203种,巢湖最少,为130种;巢湖及3条支流均以原生动物和轮虫物种数最多。浮游动物总密度为644 223 ind/L,柘皋河浮游动物密度最高,巢湖浮游动物密度最低,巢湖及3条支流原生动物密度占浮游动物总密度的比例均为最高;四个季节柘皋河浮游动物密度均为最高。浮游动物总生物量为253.14 mg/L,南淝河浮游动物生物量最高,杭埠河和巢湖浮游动物生物量较低;春季和冬季柘皋河浮游动物生物量最高,夏季和秋季南淝河浮游动物生物量最高。相较3条支流,巢湖浮游动物优势种数最少。依据理化指标,巢湖及3条支流为富营养或超富营养水平,营养水平为:南淝河巢湖柘皋河杭埠河。浮游动物群落结构和环境因子的冗余分析(RDA)表明,巢湖及3条支流浮游动物群落结构在四个季节均未能明显区分开,浮游动物群落和环境理化因子的相关性较小。

Characteristics of Zooplankton Community and Water Quality Assessment in Chaohu Lake and Its Tributaries

Zooplanktonic investigation was carried out from September 2013 to June 2014 in Chaohu Lake and three tributaries (Zhegao River, Hangbu River, and Nanfei River). Totally, 297 species of zooplankton including 124 species of protozoa, 135 species of rotifer, 29 species of cladocera, and 9 species of copepoda were found. The species number of zooplankton was the highest in Nanfei River (203), and with the lowest value (130) occurring in Chaohu Lake. Protozoa and rotifer had the highest species number in Chaohu Lake and three tributaries (Table 2, Appendix). The total abundance of zooplankton was 644 223 ind./L, Zhegao River had the highest abundance, Chaohu Lake had the lowest abundance, and the abundance of protozoa was on predominance. Zhegao River had the highest abundance of zooplankton in four seasons (Fig.2a). The total biomass of zooplankton was 253.14 mg/L, Nanfei River had the highest biomass, Hangbu River and Chaohu Lake had the lowest biomass (Table 2). Zhegao River had the highest biomass of zooplankton in spring and winter, Nanfei River had the highest biomass of zooplankton in summer and autumn (Fig.2b). Compared with three tributaries, Chaohu Lake had the lowest species number of dominant species (Table 3). Based on physiochemical parameters, it was found that Chaohu Lake and three rivers were in eutrophic or hypereutrophic status, the degree was as follows: Nanfei River>Chaohu Lake>Zhegao River>Hangbu River (Table 1). Zooplankton community structure was analyzed in relation to physiochemical parameters by redundancy analysis (RDA), the results showed that these was no obvious spatial heterogeneity of zooplankton community structure in Chaohu Lake and its three tributaries in four seasons, and physiochemical parameters were weekly correlated with the zooplankton community structure (Fig.3).