Plankton Community Structure And Its Relationships With Environmental Factors In Datong Lake

Datong Lake in Hunan province is a typical shallow lake in Dongting Lake. In this study, plankton and environmental factors in Datong Lake of Hunan Province were investigated monthly from April 2013 to March 2014, in order to develop and utilize fishery resources rationally, protect the ecological environment. Plankton community structure and its relationships with environmental factors were analyzed by canonical correspondence analysis (CCA) to provide some information on fisheries sustainable utilization in Datong Lake.Water depth, water temperature, transparency, pH, total nitrogen, nitrate nitrogen, total phosphorus, soluble phosphorus and chlorophyll a were the main parameters of water physical and chemical factors. The water nutritional levels and trophic state index (TSIm) indicated that the lake is under accelerated eutrophication status.A total of 80 species from 7 genera of phytoplankton were identified, which consisted of 26 species of Chlorophyta,21 species of Bacillariophyta,19 species of Cyanophyta,6 species of Euglenophyta,4 species of Xanthophyta,3 species of Cryptophyta, and 1 species of Pyrrophyta. Totally 46 species from 20 genera of zooplankton were identified, which consisted of 18 species of Protozoa,19 species of Rotifera,4 species of Cladoera and 5 species of Copepoda.According to the abundance and occurrence of phytoplankton, Euglena polymorphya, Cryptomonas ovate, Chroomonas acuta, Syclotella catenata, Chlorella vulgaris? Chlamydomonas orbicularis and Scenedesmus quadricauda were considered as the dominant species. According to the abundance and occurrence of zooplankton, Tintinnopsis sinensis, Brachionus diversicornis, Asplanchna priodonta, Polyarthra trigla, Filinia longiseta, Bosmina longirostris and Cyclops strenuous were considered as the dominant species.The mean annual abundance and biomass of phytoplankton were 6.58±0.66×104ind.·L-1 and 0.16±0.05 mg·L-1 respectively. The abundance and biomass were both relatively high from October and December 2013. The mean annual abundance and biomass of zooplankton were 1013±125 ind.·L-1 and 5.12±0.96 mg·L-1, respectively. The abundance and biomass were both relatively high from October to March 2014, and lowest in April. The abundance and biomass of plankton have a spatial pattern of decreasing from South to North.The range of Shannon index (H), Abundance index (D), and Pielou index (J) of the phytoplankton community were 0.72?2.08?0.38?0.75 and 0.31?0.84 respectively. The range of Shannon index (H), Abundance index (D), and Pielou index (J) of the zooplankton community were 0.31?1.88,0.11?1.39, and 0.45?0.90, respectively. The biodiversity index indicated that the lake is under accelerated eutrophication status.The CCA results indicated that water temperature and total phosphorus were the two main environmental factors affecting the plankton community structure in the Datong Lake, and pH was the main environmental factors affecting the phytoplankton community structure in the Datong Lake.