黑河干流浮游动物与水环境因子关系的多元分析

Relationship of Zooplankton and Water Environmental Factors in the Main Stem of Heihe River

研究浮游动物群落与水环境因子之间的关系,为黑河流域水体污染综合防治与生态恢复提供基础数据和理论依据。2015年4、7和12月监测黑河干流浮游动物密度、生物量与水环境因子,应用多元逐步回归分析、通径分析和典范对应分析方法进行研究。结果表明:黑河干流共鉴定浮游动物62种,其中轮虫8科21属44种,枝角类5科9属13种,桡足类2科4属5种。浮游动物种类以轮虫等小型个体为主,其密度、生物量及种群分布受到水环境因子的共同作用,各断面水环境因子的差异是浮游动物数量变动及分布情况不同的主要原因。上游浮游动物数量变动受水体叶绿素a和溶氧影响,高锰酸盐指数和总磷决定浮游动物的分布;中游浮游动物数量变动受叶绿素a和透明度制约,其分布与pH、溶氧、电导率、总磷、高锰酸盐指数、叶绿素a密切相关;影响下游浮游动物密度的主要因子是叶绿素a、溶氧、总磷和电导率,生物量则与叶绿素a、总氮和电导率相关,总磷和溶氧共同决定下游浮游动物的分布。

Heihe River is the second largest inland river in northwest China,with a basin area of 14.29×10^4 km.With rapid development of industry and agriculture in the basin,pollutant discharges to the river have increased,leading to serious deterioration of water quality.In this study,we investigated the zoo-plankton community structure in the main stem of Heihe River in 2015and analyzed its relationship with water environmental factors using multiple stepwise regression,path coefficient analysis and canonical cor-respondence analysis(CCA).The aim was to provide baseline and theoretical evidence for comprehensive prevention and control of water pollution as well as ecological restoration in the Heihe River basin.In A-pril,July,and December of 2015,a zooplankton investigation was carried out at 46sampling sites in the up-per,middle and lower reaches of Heihe River,focusing on zooplankton density and biomass.Water envi-ronmental factors were also measured including transparency,conductivity,dissolved oxygen(DO),total nitrogen(TN),total phosphorus(TP),pH,permanganate Index(COD Mn)and chlorophyll a(Chl-a).A total of 62zooplankton species was identified,including 44rotifer species(22genera,8families),13 cladocera species(9genera,5families)and 5copepoda species(4genera,2families).The zooplankton community was dominated by the small rotifers.Water environmental factors affected the density,biomass and distribution of zooplankton and were primarily responsible for variations in the zooplankton distribu-tion of different river sections.The density and biomass of zooplankton in the upper reach of Heihe river were affected by Chl-a and DO levels,and the distribution was related to COD Mn and TP.Chl-a and water transparency were the primary factors affecting zooplankton density and biomass in the middle reach,and distribution was closely related to pH,DO,conductivity,TP,COD Mn and Chl-a.The primary factors af-fecting zooplankton density in the lower reach were DO,Chl-a,TP and conductivity,while biomass was related to Chl-a,TN and conductivity.The distribution of zooplankton in the lower reach was related to TN and DO.