Abstract: Seasonal variation of crustacean zooplankton community structure in Lake Jiaoganghu was studied from October 2013 to July 2014. The environmental factors affecting the community structure of crustacean zooplanktons were analyzed by CCA method. The results showed that a total of 17 species were recorded, among which 11 species (8 genera) belong to Cladocera and 6 species (5 genera) belong to Copepoda. The dominant species of Cladocera were Diaphanosoma sp., Alona rectangula and Bosmina fatalis. Microcyclops vaticans and Thermocyclops hyalinus dominated the Copepod community. There was a significant seasonal variation in the density and biomass of crustacean zooplanktons in Lake Jiaoganghu. The mean density and biomass of crustacean zooplanktons were (196.30±313.75) ind·L^-1 and (1.80±3.18) mg·L^-1 respectively, and both much higher in spring and summer than in autumn and winter. The maximum density \[(31.47±51.09) ind·L^-1\] and biomass \[(2.82±4.58) mg·L^-1\] of Copepodas community occurred in summer, while the maximum Cladocerans density \[(28.53±55.91) ind·L^-1\] and biomass \[(0.61±0.70) mg·L^-1\] occurred in summer and spring respectively. The mean Shannon diversity index of crustacean zooplanktons was 1.07±0.81, with the maximum value occurring in spring. The result of CCA analysis showed that water temperature, pH value, phytoplankton biomass and nutrient contents were the important factors affecting seasonal variations of crustacean zooplankton community in Lake Jiaoganghu.

Key words: leaching, ammonia volatilization, denitrification, nitrogen management, runoff, nitrogen use efficiency