| In this paper, investigation had been made about the community structure ofmetazoan zooplankton(including Rotifers, Cladocera and Copepoda) in QingcaoshaReservoir during a period of January, April to December2011. The paper analyzed thecorrelationship between community structure of metazoan zooplankton and ecologicalenvironmental factors and combined the physical and chemical indicators to makecomprehensive evaluation of water quality in Qingcaosha Reservoir so that couldprovide basic material for the prevention of Qingcaosha Reservoir eutrophication,enhancing self-purification and improving water quality capacity.Analysis showed that during the investigation64kinds of metazoan zooplanktonwere observed in total, including39species of Rotifers which took61%of the totalspecies, belonging to8families and18genera,11species of Cladocera which took17%of the total number, belonging to4families and9genera,14species of Copepoda(including nauplii and copepod larvae) were22%, belonging to4families and9genera.As to metazoan zooplankton, the dominant species of Rotifers were Trichocerca pusilla,Brachionus angularis, Keratella quadrata, Keratella valga, Triahcerca cylindrica andPolyarthra trifle, and which of Cladocera were Bosmina fatalis and Ceriodaphniacornuta, the dominant species of Copepoda were Mesocyclops leuckarti, Sinocalanusdorrii and Limnoithona sinensis. Species composition of metazoan zooplanktonfollowed seasonal variation, the kind of metazoan zooplankton species reached maxiumat autumn, then spring and summer followed, winter was the least season. Theoutstanding dominant species in May was Ceriodaphnia cornuta, whose dominance was0.95(Y=0.95).Annual density of metazoan zooplankton was469.1ind./L, which was mainlyconstituted of Rotifers whose average density was403.9ind/L, taking86.1%of the total desity. Cladocera had an average density of42.5ind/L,9.1%of the total density. Theaverage density of Copepoda was22.7ind/L,which was4.8%. Both species number anddensity of rotifers had a higher proportion in metazoan zooplankton community.Density of metazoan zooplankton reached to peak in the autumn, which wasfollowed by spring and summer, and winter density was significantly lower than others.In addition, the average density of Rotifers was that autumn> summer> spring> winter,the average density of Cladocera was that spring> autumn> summer> winter, and theaverage density of Cladocera was that winter> autumn> spring> summer.Spatial variation of density of metazoan zooplankton in different sampling sitescould be described that St6in the midstream of the reservoir had the highest densitywhich was861.1ind/L.St11that located in the Yangtze River, outside the reservoir, hadthe lowest density which was18.2ind/L. St2in the upstream was the lowest one among10internal sites having a density of224.0ind/L. Density of Rotifers was highest at St6,up to791.6ind/L. The highest density of Cladocera was153.3ind/L at the St5. Thehighest density of copepoda was at St9, up to49.2ind/L. However, those sites havinghigher water depth,such as St4, St6, St8, St9and St10, didn’t have obvious changepattern on species and density of metazoan zooplankton.Moreover, this paper researched the correlation between density of metazoanzooplankton community and a variety of environmental factors. The result showed thata variety of environmental factors took different effects on different groups of metazoanzooplankton. Through correlation analysis (SPSS18.0), conclusions showed thatRotifers had a highly significant positive correlation (r=0.279, P <0.01) with watertemperature(T) and that Cladocera had a significantly negative correlation (r=-0.248,P＜0.05) with dissolved oxygen (DO). Copepoda and water temperature(T) had a verysignificant negative correlation (r=-0.347, P <0.01). Copepoda had a very significantpositive correlation (r=0.302, P <0.01, r=0.307, P <0.01) with both dissolved oxygen(DO) and transparency (SD). Using GAM generalized additive model analyzed thefunctional relationship between environmental factors and zooplankton bio-density hadconcluded that the relation between Rotifers density and water temperature(T) wassignificant(P<0.1), between Cladocera density and water temperature(T) was alsosignificant(P<0.1), while Cladocera density had a more significant relation withtransparency(SD) and dissolved oxygen(DO)(P<0.05), and the relationship betweenbiological density of Copepoda and transparency SD was significant (P <0.1). Besides, the correlationship between zooplankton density with other environmental factors wasless remarkable.While taking advantage of bio-indicator method and diversity index, respectivelymade water quality biological evaluation of Qingcaosha Reservoir. In the view ofdominant species of metazoan zooplankton,the trophic types of Qingcaosha water bodywas mesotrophic. The Shannon-Weaner diversity index of Rrotifers was between2.64to3.77, Margalef diversity index changed in the scope of1.32to2.91,and Simpsondiversity index was between0.77to0.90. Shannon-Weaner diversity index of Cladocerawas between0.18to1.57, and Margalef diversity index was in the scope of0.55to2.75,Simpson diversity index was between0.04to0.58.While Shannon-Weaner diversityindex of Copepoda was in a range of0.94to1.73, Margalef diversity index changedbetween1.20to2.09,and Simpson diversity index was between0.30to0.63. As thespecies number and density of Cladocera and Copepoda were too low to take theirdiversity index as evaluation standard, only Shannon-Weaner diversity index andMargalef diversity index of Rotifers had a responsible evaluation of water qualityanalysis in three groups metazoan zooplankton of Qingcaosha Reservoir,and the indexconcluded that water quality of Qingcaosha Reservoir belonging to the β-pollution type.In addition, according to the Q-value of Rotifers biological index, Q-value of11samplingsites in Qingcaosha Reservoir was1, which agreed with the Q-value of each site, weresulted that water quality of Qingcaosha Reservoir was mesotrophic.As a combination of evaluation methods, water quality of Qingcaosha Reservoirwas in sewage and determined as mesotropher. |
PDF Full Text Request