东钱湖浮游生物调查以及水质生态学评价

The Research of Plan Kton and Ecology Evaluation of Water about Dongqian Lake

浮游生物的群落组成、细胞密度、优势种群等与水体的营养程度密切相关，是水质污染及营养水平的重要标志。为了了解东钱湖的水质状况，于2007年3月、7月和11月对该湖泊的水质和浮游生物分布进行了调查。结果表明，东钱湖综合营养状态指数（TIL）在38—55之间，属于中～富营养化水平。浮游植物密度为4．65×10^4～6．07×10^6个／升，7月大于3月和11月。浮游植物以蓝藻为主，主要优势种为小席藻，螺旋藻等富营养化指示种。从多样性指数和均匀性指数分析来看，东钱湖水质属于中度-重度污染，这与采用相关加权综合营养状态指数法的评价结果一致。浮游动物密度为44—333个，升，3月份主要优势种为长肢多肢轮虫和壶状臂尾轮虫，7月份优势种群为晶囊轮虫和角突臂尾轮虫，这几种轮虫为富营养化指示种。

The plankton community composition, cell density, the dominant species, which were closely related to the water nutritional level were important indicators of the water pollution and nutrition level. In March, July and November of 2007, the water quality and plankton distribution of Dongqian Lake were investigated to evaluate its trophic state. According to the comprehensive trophic level index （TLI）, the values of Dongqian Lake were between 38 and 55. It showed that the lake was between mesotrophic and nutritious level. The phytoplankton abundances varied from 4.65 × 10^4 to 6.07 × 10^6 ind· L. and which were higher in July than in March, November. The phytoplankton was primarily composed of Cyanophyta. Most of the dominant species were eutrophication indicators such as Phormidium tenus and Spirulina sp.. From the diversity and homogeneity index analysis, the Dongqian Lake water is between the middle pollution and the heavy pollution, which is the same to the evaluation results of nutritional status related to the lake,with the use of the comprehensive trophic level index （TLI）.The zooplankton abundances were between 44 ind·L to 333 ind· L . In March, the dominant species were Polyarthra and Brachious urceus, in July the dominant species were Asplanahna and Brachious angularis, and the dominant rotifera were mostly eutrophication indicators.