长江三口-西洞庭湖环境因子对浮游动物群落组成的影响

了解长江三口(藕池口、松滋口、太平口)和西洞庭湖浮游动物群落结构特征及主要环境影响因子,探究洞庭湖来水及浮游动物多样性和现存量的周年动态变化,运用典范对应分析(CCA)浮游动物分布与环境因子之间的关系,可为洞庭湖水生态环境保护及污染防治提供数据支撑,于2016年11月、2017年3月和8月对长江三口及西洞庭湖18个断面进行了浮游动物调查。结果显示,共检出浮游动物4门、40种,长江三口浮游动物密度为9~323个/L,生物量为0.006~0.319 mg/L,西洞庭湖浮游动物密度为9~45个/L,生物量为0.019~0.045 mg/L,枯水期与丰水期浮游动物密度差异显著,长江三口浮游动物密度均值(67个/L)高于西洞庭湖(23个/L);三口的优势类群为无节幼体(Nauplii)、桡足幼体(Copepodid)、曲腿龟甲轮虫(Keratella valga),西洞庭湖优势种为螺形龟甲轮虫(Keratella cochlearis)、普通表壳虫(Arcella vulgaris)、曲腿龟甲轮虫(Keratella valga);长江三口浮游动物Shannon-Wienner指数及Pielou均匀度指数分别为1.07和0.77,西洞庭湖分别为1.17和0.80。CCA分析表明,水温(WT)、总氮(TN)、总磷(TP)和正磷酸盐(PO 4-P)是影响长江三口浮游动物分布的主要因子,而WT、TN是影响西洞庭湖区浮游动物分布的主要因子。

Effects of Environmental Factors on Zooplankton Community Composition in the Three Outlets of Yangtze River to West Dongting Lake

The three outlets (Ouchi, Songzi and Taiping) that connect the Yangtze River with West Dongting Lake play an important role in flood control and water resource utilization in Dongting Lake. In this study, we investigated the zooplankton community structure and the primary environmental factors at 18 sampling sites in the three channels and west Dongting Lake in November 2016, and March and August 2017. The results were used to explore the annual dynamics of the three channels and Dongting Lake and characterize zooplankton diversity and stock. The relationship between zooplankton distribution and environmental factors was analyzed by canonical correspondence analysis (CCA). The research provides data to support the ecological environment protection and pollution prevention of Dongting Lake. A total of 40 zooplankton species from 4 phyla was detected, with dominance by Rotifers (21 species, 52.5%), Protozoa (8 species, 20%), Cladocera (7 species, 17.5%) and Copepoda (2 species, 5%). Zooplankton density and biomass in the three channels were in the range of 9 - 323 ind/L and 0.006 - 0.319 mg/L, and the ranges in the West Dongting Lake were 9 - 45 ind/L and 0.019 - 045 mg/L. The average density in the three outlets (66.5 ind/L) was higher than in west Dongting Lake (23 ind/L) and the differences in zooplankton density between dry and wet periods were significant. In terms of the dominant groups, Nauplii, Copepoda and Keratella valga dominated in the outlets , and west Dongting Lake was dominated by Keratella cochlearis, Arcella vulgaris and Keratella valga. The Shannon-Wiener diversity and Pielou evenness indices were 1.07 and 0.77 in the outlets and 1.17 and 0.80 in the West Dongting Lake. CCA of zooplankton community and water environmental factors shows that water temperature (WT), total nitrogen (TN), total phosphorus (TP) and orthophosphate (PO4-P) were the primary factors affecting the distribution of zooplankton in the three outlets , while WT and TN were the primary factors affecting the distribution of zooplankton in west Dongting Lake.