Comparative Study On Community Structure Of Metazo-Oplankton Of Xukou Bay And Meiliang Bay In Lake Taihu

To understand the influence of eutrophication on the community structure of zooplanktonin Lake Taihu, a comparative study on annual variation of community structure ofzooplankton and the correlation between environmental factors and zooplankton wasconducted in Meiliang Bay and Xukou Bay in Lake Taihu from Sep.2012to Aug.2013. Thedata indicated that the level of eutrophication in Meiliang Bay was higher than that in XukouBay. Twenty-nine species of zooplankton was identified in Xukou Bay, and the number ofspecies of Copepoda, Cladocera and Rotifer were4,5and20, respectively. Thirty-two speciesof zooplankton was identified in Meiliang Bay, the number of species of Copepoda,Cladocera and Rotifer were5,7and20Rotifer, respectively.The annual average abundanceand biomass of zooplankton were113ind./L and0.398mg/L in Xukou Bay,248ind./L and3.010mg/L in Meiliang Bay. The analysis showed that the annual average abundance andbiomass of Meiliang Bay was significant higher than that in Xukou Bay (P<0.01), and thebiological diversity of zooplankton in Meiliang Bay was significant higher than that in XukouBay.The abundance of zooplankton of Xukou Bay and Meiliang Bay were both higher insummer and autumn, and lower in spring and winter, the biomass of zooplankton in the twobays were both highest in summer, and in Xukou Bay was lowest in autumn, while inMeiliang Bay was lowest in winter. The biological diversity of zooplankton was higher inMeiliang Bay than that in Xukou Bay.Rotifer accounted for the largest proportion of zooplankton abundance and Cladoceraaccounted for the smallest in Xukou Bay, which accounted for50.4﹪and1.97﹪respectively,while Cladocera accounted for the largest proportion of zooplankton abundance andCopepoda accounted for the smallest proportion in Meiliang Bay which accounted for49.23﹪and22.54﹪respectively. Copepoda accounted for the largest proportion of zooplanktonbiomass in Xukou Bay, Cladocera accounted for the largest proportion in Meiliang Bay, andRotifer accounted for the smallest proportion of zooplankton biomass in two bays.The dominant species of zooplankton were cochlearia Keratella and Polyarthra trigla inXukou Bay，and the annual abundance of cochlearia Keratella and Polyarthra trigla were25ind./L and16ind./L, respectively. In Meiliang Bay the dominant species of zooplankton wereBosmina coregoni and Moina macrocopa, their annual abundance were63ind./L and31ind./L respectively. In Xukou Bay, the dominant species of zooplankton were Polyarthratrigla and Conochilus dossuarius in spring, cochlearia Keratella and Polyarthra trigla insummer and autumn, Polyarthra trigla and Limnoithona sinensis in winter; in Meiliang Bay,the dominant species of zooplankton were Bosmina coregoni and Sinocalanus dorrii in spring, Bosmina coregoni and Moina macrocopa in summer, Bosmina coregoni and Ceriodaphniacornuta in autumn, Bosmina coregoni and Polyarthra trigla in winter.Correlation analysis indicated that there were significant positive correlation between theabundance of zooplankton and nitrate nitrogen and water temperature, and greatly significantpositive correlation between the abundance of zooplankton and suspended solidsconcentration, and there were greatly significant positive correlation between the biomass ofzooplankton and and nitrate nitrogen and water temperature and suspended solidsconcentration. The results of this research showed that response of zooplankton toeutrophication were different in different biotope in Lake Taihu.