A Comparative Study On The Community Structure Of Epizoic Zooplankton In Qinhuai River And Baima Lake

Qinhuai River and Baima Lake are important water resources in Jiangsu Province.Qinhuai River is located in the south of Jiangsu Province,while Baima Lake is located in the north of Jiangsu Province.In the past,both Qinhuai River and Baima Lake were greatly affected by human activities,and the water quantity decreased,water quality deteriorated and biomass decreased.In recent years,the two governments attach great importance to water recovery,so it is of great significance to select these two water bodies to study the community structure of zooplankton for guiding their water recovery.This article through to investigation and analysis the climate conditions,water environment,metazoan zooplankton diversity of Qinhuai River and Baima Lake,compare the two different conditions of metazoan zooplankton community structure,and analysis of the impact of environmental factors on metazoan zooplankton,in order to find out the differences in the metazoan zooplankton of rivers and lakes,for guiding the fishery industry,adjust,improve water quality,monitoring of water environment change is of great significance.In this study,metazoan zooplankton and water physicochemical factors in Qinhuai River and Baima Lake were sampled,identified and determined according to seasons and sampling point,and relevant data were recorded to obtain the water quality physicochemical factors and composition of metazoan zooplankton in water,and then the relationship between the population and various factors in water was analyzed by computer.The main results are as follows:1.According to the observation and collection of samples,46 species of metazooplankton were found in Qinhuai River throughout the year,including 27 species of Rotifer,10 species of Cladocera and 9 species of Copepods.The number of species observed in autumn was the most,and that in winter was the least.Among the three types of metazooplankton,rotifers had the most species and number,and Cladoceratops and Copepods were significantly less.The dominant phytoplankton species in the Qinhuai River varied with the seasons,Polyarthra trigla,Keratella cochlearis,Brachionus calyciflorus,Bosmina coregoni were the dominant species in spring.Polyarthr,KeratelIa valaa,Bosmina coregoni,Monia macrocopa,Thermocyclops dybowskii were the dominant species in summer.Brachionus calyciflorus,Brachionus angularis and Daphnia leuchtenbergianum were the dominant species in autumn.Filinia maior,Bosmina coregoni,and Bosmina fatalis were the dominant species in winter.2.In addition,the density and biomass of metazoan zooplankton in Qinhuai River were calculated,and it was found that the density and biomass had obvious seasonal changes.The maximum value of the overall biomass appeared in autumn,the minimum in winter,and the summer was more than the spring.Rotifers occupy the maximum value of all data indexes.The index of diversity,richness and evenness of zooplankton in Qinhuai River was calculated.3.Canonical Correspondence Analysis(CCA)analysis showed that the physicochemical factors acting on the Qinhuai River 's metazoan zooplankton including temperature(TEMP),dissolved oxygen(DO),ammonia nitrogen(NH4+-n),transparency,turbidity,permanganate,etc.4.60 species of metazoan zooplankton,including 35 species of Rotifers,15 species of Cladoceratae and 10 species of Copepods were observed in Baima Lake throughout the year.Different from the Qinhuai River,the peak value of metazoan zooplankton species in Baima Lake was observed in summer,and the lowest value was observed in winter.The dominant species of Rotifers were K.cochlearis,B.calyciflorus,P.trigla.The dominant species of the Cladoceratae were Bosmina longirostris,B.coregoni,D.leuchtenbergianum.The main dominant species of Copepods were Mesocyclops leuckarti and Thermocyclops kawamurai.5.The density and biomass of metazoan zooplankton in Baima Lake also have obvious seasonal variation.Different from that in Qinhuai River,the density of metazoan zooplankton in Baima Lake was expressed as > in spring,> in summer,> in autumn and rotifers in winter.and Rotifers taking the largest proportion in the overall density.In spring,> in autumn,> in summer,and > in winter,Rotifers and Cladocerns contributed the most to the total biomass.The indexes of biodiversity,richness and evenness of Baima Lake were calculated.6.CCA analysis showed that temperature,chlorophyll a,ammonia nitrogen,dissolved oxygen and pH were the main physical and chemical factors acting on the structure of the metazoan zooplankton community in Baima Lake.