里下河腹部地区典型湖泊浮游动物演替特征及水质评价

Zooplankton succession characteristics and water quality evaluation of typical lakes in the hinterland of Lixia River

为探究大纵湖浮游动物群落演替特征和驱动因素,综合评价输水工程稳定运行后其水环境状况,于2017年1月至2019年12月在位于里下河腹部地区的大纵湖开展为期3 a的浮游动物及环境因子逐月调查。调查结果表明,调查期间在大纵湖共鉴定出浮游动物49种,其中轮虫、枝角类及桡足类分别为33种、9种和7种;种间联结性检验统计量表明,大纵湖优势种总体上呈显著正关联,且关联性逐年增长,浮游动物群落结构趋于稳定;浮游动物平均密度为623.17个/L,呈下降趋势,平均生物量为1.63 mg/L,呈上升趋势,相较于轮虫,枝角类和桡足类的比重逐渐上升。冗余分析结果表明,叶绿素a、总氮和水温是影响大纵湖浮游动物物种演替的重要因子。采用Shannon-Wiener多样性指数、Margalef丰富度指数和Pielou均匀度指数评价大纵湖污染情况,结果均为寡污,B/T指数与TLI富营养评价结果相符合,大纵湖处于中-富营养状态;浮游动物对大纵湖水温、营养盐和叶绿素a的变化有良好的响应。

This study conducted a three-year monthly survey of zooplankton and environmental factors in typical Dazong Lake from January 2017 to December 2019,in order to explore the succession characteristics and driving factors of zooplankton community in Dazong Lake and comprehensively evaluate its water quality after the stable operation of water delivery project.The results show that 49 species of zooplankton were identified in Dazong lake during the survey,including 33,9 and 7 species of rotifers,cladocerans and copepods respectively.The interspecific connectivity statistics show that the dominant species in Dazong Lake showed a significant positive correlation overall,and the correlation increased year by year,which meant the zooplankton population structure tended to be stable.Average density was 623.17 per liter,showing a downward trend,and the average biomass was 1.63 mg/L,showing an upward trend.Compared with rotifers,the proportion of cladocerans and stilts gradually increased.The results of RDA redundancy analysis show that chlorophyll a,total nitrogen and water temperature were important factors affecting the succession of zooplankton species in Dazong Lake.The organic pollution of Dazong Lake was evaluated by Shannon-Wiener diversity index,Margalef richness index and Pielou evenness index.The results were low pollution and the B/T index was consistent with the results of TLI eutrophication evaluation,thus Dazong Lake was in a medium eutrophic state.Zooplanktons have a good response to the changes of environmental factors in Dazhong Lake,which can be applied to the evaluation of water ecological status in the lake area.