| Lake Huayanghe and Lake Jiaoganghu are located in the middle and lower reaches of the Yangtze river and in the middle and upper reaches of the huaihe river respectively, and the two lakes are the very important for migratory birds wintering and fish breeding grounds. The contrast research of metazoan zooplankton community structure in different basin is of great significance to explore the plankton community succession and the management of lakes and rational utilization and distribution of water resources. At present, the research on metazoan zooplankton community structure is less.The spatial and temporal distribution characteristic and the physical and chemical factor of metazoan zooplankton in Lake Huayanghe and Lake Jiaoganghu were studied. This paper studied the processes of spatial-temporal variability in the metazoan zooplankton community,standing crop,dominance species in Lake Huayanghe and Lake Jiaoganghu. We used multivariate statistical analysis software and correlation analysis software to further explore the influence of environmental factors for metazoan zooplankton community structure in different environmental factors. The main resultsare as follows:1. The results showed that a total of 53 species (34 genera) was recorded, among which 39 species were belonging to Planktonic rotifer,8 species were belonging to Cladocera and other 6 species were belonging to Copepoda respectively. The highest value of metazoan zooplanktons species were found in autumn, and the lowest one in winter.In the species composition of metazoan zooplanktons, rotifer accounted for the most of the total.There was a significant seasonal variation and spatial dynamics in the distribution of the dominant species of metazoan zooplanktons in Lake Huangyanghe. The dominant species in spring was Keratella cochlearis, Asplanchna priodonta, Bosmina longirostris, Sinocalanus dorrii. The dominant species in summer was Brachionus angularis, B. forficula, Trichocerca stylata, Diaphanosoma saris, B. longirostris, Microcyclops vaticans, Limnoithona sinensis. The dominant species in autumn was B. angularis, Schizocerca diversicornis, B. longirostris, L. sinensis. The dominant species in winter was Polyarthra trigla, B. fatalis, Sinocalanus dorrii, L. sinensis.There was also a significant seasonal variation and spatial dynamics in the density and biomass of metazoan zooplanktons in Lake Huangyanghe. The density of metazoan zooplanktons in autumn was much higher than other seasons and the variation trend of density was autumn (2061.62 ind./L)>winter (717.18 ind./L)>spring (413.69 ind./L)>summer (223.08 ind./L). There were similar spatial distribution of density of metazoan zooplanktons. In general, the annual average density decreased from southwest to northeast, the density of Lake Longganhu was higher than Lake Huangdahu, and the lowest value occured in Lake Pohu.The variation trend of biomass was autumn (12.67 mg/L)>spring (7.86 mg/L)>summer (3.40 mg/L)>winter (1.77mg/L). There were also similar spatial distribution of biomass of metazoan zooplanktons. In the density and biomass composition of metazoan zooplanktons, rotifer and Copepoda accounted for the most of the total.The variation trend of Shannon-Wiener diversity index was summer (2.86)>autumn (2.64)>spring (2.37)>winter (1.98).Using the diversity index to evaluate the water quality, the water quality in Lake Huayanghe was moderate pollution or almost no pollution.The result of Pearson’s correlation and RDA analysis showed that water temperature, Water transparency, turbidity, chlorophyll a, COD, pH value and nutrient contents were the important factors affecting seasonal variations of metazoan zooplanktons community in Lake Huayanghe.2. A total of 68 species was recorded, among which 51 species were belonging to Planktonic rotifer,11 species were belonging to Cladocera and other 6 species were belonging to Copepoda respectively. The highest value of metazoan zooplanktons species were also found in autumn, and the lowest one in winter. The dominant species of Planktonic rotifer was A. priodonta, K. cochlearis, P. trigla. The dominant species of Cladocera was Diaphanosoma sp., Alona rectangular, B. fatalis. And the dominant species of Copepoda was M. vaticans and Thermocyclops hyalinus.There was also a significant seasonal variation and spatial dynamics in the density and biomass of metazoan zooplanktons in Lake Jiaoganghu. In the density and biomass composition of metazoan zooplanktons, rotifer and Copepoda accounted for the most of the total. The density of metazoan zooplanktons in spring was much higher than other seasons and the variation trend of density was spring (669.48 ind./L)>winter (500.70 ind./L)>summer (348.38 ind./L)>autumn (166.28 ind./L). In general, the annual average density increased from west to east. The variation trend of biomass was summer (3.49 mg/L)>spring (2.89 mg/L)> autumn (1.07 mg/L)>winter (0.72 mg/L). In general, the annual average biomass was higher in the west, and lower in the east of Lake Jiaoganghu.The variation trend of Shannon-Wiener diversity index was summer (2.90)> autumn (2.71)>spring (2.01)>winter (1.87). Using the diversity index to evaluate the water quality, the water quality in Lake Huayanghe was moderate pollution.The result of Pearson’s correlation and RDA analysis showed that water temperature, pH value, dissolved oxygen, phytoplankton biomass and nutrient contents were the important factors affecting seasonal variations of Crustacean zooplanktons community in Lake Jiaoganghu.And the important factors affecting seasonal variations of Planktonic rotifer community were phytoplankton biomass, water temperature, pH, electrical conductivity, dissolved oxygen, water transparency, and nitrate nitrogen.The metazoan zooplankton community structure of the algae type Lake-Lake Huayanghe and the grass type lake-Lake Jiaoganghu and the relationship between the environmental factors were studied to provide theoretical basis for the management of lakes and rational utilization and distribution of water resources. |
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