太湖流域平水期水生态功能区浮游动物群落结构特征

Analysis on Structure Characteristics of Zooplankton Community in Water Ecological Function Zones of Taihu Basin During Normal Season

为了解太湖流域平水期水生态功能分区浮游动物群落结构特征,于2018年5月对太湖流域201个采样点进行了浮游动物群落调查和水质监测。结果表明,浮游动物共检出122种,隶属于3类49属,以轮虫类和枝角类种类数居多。Ⅰ、Ⅱ、Ⅲ和Ⅳ级区都以轮虫类丰度居多。Shannon-Wiener指数(H)、Simpson指数(D)、Pielou指数(E)均在Ⅰ级区最大,分别为2.28、0.84和0.47。共检出19种优势种,其中富营养指示物种占60%。Ⅱ级区的优势种最多,其中螺形龟甲轮虫无脊变种和角突臂尾轮虫是最优势种,影响Ⅱ级区的水质。通过典范对应分析(CCA)可知,浮游动物优势种群落结构与TP、TN显著正相关。通过Pearson分析可知Ⅰ级区、Ⅱ级区、Ⅲ级区和Ⅳ级区物种都与TP显著正相关,随着分区等级的提升,与TP的相关性显著提升,并且与COD_(Mn)和TN相关性也显著提升。水体浮游动物种群结构的变化以及水体富营养化的状态主导因子是P。综上,2018年太湖流域平水期处于富营养状态,水质状态为中污染,太湖流域藻华治理应以限制磷排放、降低TP含量为主。浮游动物群落结构影响了生态功能区的划分。

In order to understand the characteristics of zooplankton community structure in the water ecological function zoning of the Taihu Lake Basin during the normal season, the zooplankton community survey and water quality monitoring were carried out at 201 sampling points in the Taihu Lake Basin in May 2018.122 species of zooplankton were detected, belonging to 49 genera of 3 categories, with the majority of rotifers and cladocera. Class Ⅰ,Ⅱ,Ⅲ and Ⅳ areas are dominated by rotifers. Shannon-Wiener index(H), Simpson index(D) and Pielou index(E) were the largest in Class Ⅰ areas, which were 2.28, 0.84 and 0.47. A total of 19 dominant species were detected, 60 % of which were eutrophic indicating species. The dominant species in Class Ⅱ area were the most. Keratella cochlearis and Brachionus angularis were the most, which affected the water quality in Class Ⅱ area. Canonical correspondence analysis(CCA) results showed that the community structure of dominant zooplankton species was significantly positively correlated with TP and TN. According to Pearson analysis, species in Class Ⅰ,Ⅱ,Ⅲ and Ⅳ areas were significantly positively correlated with TP. With the increase of zoning grade, the correlation with TP was significantly increased, and the correlation with COD_(Mn)and TN was also significantly increased. The dominant factor for the change of zooplankton population structure and eutrophication of water body is P. In summary, in 2018, the Taihu Lake Basin was in a eutrophic state in the normal water period, and the water quality was in a medium pollution state. The treatment of algal blooms in the Taihu Lake Basin should be focused on limiting phosphorus emission and reducing TP content. The structure of zooplankton community influences the division of ecological functional zones.