太湖滨岸带浮游动物群落结构特征与环境因子的典范对应分析

Canonical Correspondence Analysis Between Zooplankton Community Structure and Environmental Factors in the Littoral Zone of Taihu Lake

探讨浮游动物群落结构与环境因子的关系,为太湖水质监测提供方法,为富营养化治理与水生态修复提供理论支持。2016年8月进行了太湖水质状况及浮游动物群落调查,利用物种多样性指数和物种丰富度指数分析了太湖浮游动物群落结构特征,在此基础上,采用典范对应分析(CCA)探讨太湖浮游动物群落结构特征与环境因子的相互关系。结果表明,太湖不同湖区湖滨带水体水质总体评价为劣V类,总氮、总磷均值分别为(2.06±0.13)mg/L、(0.22±0.02)mg/L,叶绿素a平均含量为(65.35±9.09)mg/L。本次调查共检出浮游动物29种,其中桡足类5种,枝角类8种,轮虫16种;太湖浮游动物密度均值为(100±11)个/L,其中竺山湾浮游动物密度最高,为(273±54)个/L,胥口湾密度最低,仅为(31±6)个/L;太湖浮游动物生物量均值为(4.45±0.99)mg/L,生物量最高的是竺山湾,为(17.70±6.48)mg/L,胥口湾浮游动物生物量最低,为(1.03±0.23)mg/L。相关性分析表明,浮游动物各表征指标均与叶绿素a含量呈现显著正相关性。典范对应分析结果表明,浮游动物分布主要与溶解性总氮、总磷、透明度、溶解氧及pH值显著相关。

Taihu Lake is one of the five largest freshwater lakes in China. Eutrophication in Taihu Lake has become increasingly serious since the late 1970 s and early 1980 s, and this problem is now receiving increased attention. Zooplankton are sensitive to pollution, and the community structure and distribution of zooplankton vary with nutritional status. In this paper, we investigated the zooplankton community structure and water quality status at 130 sites in seven areas of Taihu Lake in August 2016. The relationship between zooplankton community structure and environmental factors was studied using canonical correspondence analysis(CCA). The study aimed to provide theoretical support for eutrophication control and ecological restoration in Taihu Lake. The zooplankton community structure was characterized by zooplankton species composition, density, biomass, species diversity index and species richness index. Water quality parameters including pH, water temperature(T), dissolved oxygen(DO), Secchi disk depth(SD), total nitrogen(TN), total phosphorus(TP), ammonia nitrogen(NH+4), phosphate(PO43-), and chlorophyll a(Chl-a) were used to evaluate the eutrophication degree of Taihu Lake. The overall water quality in riparian zones of the different areas of Taihu Lake was inferior to Class V. The average values of TN and TP were(2.06±0.13) mg/L and(0.22±0.02) mg/L respectively, and the average content of Chl-a was(65.35±9.09) mg/L. A total of 29 zooplankton species were observed in the survey, including 5 species of copepods, 8 species of cladocera, and 16 species of rotifers. The mean density of zooplankton in Taihu Lake was(100±11) ind/L, with the maximum density of(273±54) ind/L in Zhushan Bay and the minimum density of(31±6) ind/L in Xukou Bay. The mean biomass of zooplankton in Taihu Lake was(4.45±0.99) mg/L, with the highest density of(17.70±6.48) mg/L in Zhushan Bay, and the lowest density of(1.03±0.23) mg/L in Xukou Bay. Correlation analysis shows that zooplankton characterization indices all had significant positive correlation with Chl-a. The results of CCA show that the community structure of zooplankton was significantly related to dissolved TN, TP, SD, DO and pH.