太湖控藻围隔内浮游动物的群落结构特征及水质评价

Zooplankton Community Structure and Water Quality of the Biological Control Enclosure Ecosystem in Taihu Lake

为探明放养鲢、鳙鱼对太湖水质和浮游动物的影响,于2013年6月10日至10月10日在太湖西北部风浪较小的马山镇与竺山之间的湖湾设置大型围隔,放养鲢、鳙鱼进行生物控藻试验,放养比例为3∶1,密度为50g/m3,并参照相关评价标准进行水质评价。结果表明：生物控藻区围隔内共有浮游动物4门52种,其中,轮虫类21种、原生动物12种、枝角类11种和桡足类8种,优势种共有12种,轮虫类和枝角类为全年的主要优势种;浮游动物平均密度为388.97ind/L,平均生物量为3.98mg/L;生物多样性指数、均匀度指数分别为2.37和0.38,生物控藻区水体处于中污染水平;水体综合营养状态指数为51.84~61.96,水体处于轻度富营养化状态,水质为轻度污染;两种水体污染评价方法的评价结果不一致,但均表明太湖水体已受到一定程度的污染。

The biological control enclosure ecosystem between Mashan Town and Zhushan Lake was stocked with silver carp and bighead carp according to 3∶1ratio and 50g/m3 from 10,June to 10,October in 2013 and then the water quality was evaluated by reference to the relevant evaluation standard to discuss the effects of stocking silver carp and bighead carp on water quality and zooplankton in Taihu Lake.Results：There are 52 zooplankton species including 21 Rotifers,12 Protozoa,11 Cladocera and 8Copepods.The dominant species are 12 species.Rotifers and Cladocera are main dominant species in a year.The average density and biomass of zooplankton are 388.97ind/L and 3.98mg/L respectively.The biological diversity index and evenness index of zooplankton is 2.37 and 0.38 separately,which indicates that the water quality of the biological control enclosure ecosystem is at moderate pollution level.The water comprehensive nutrition index of the biological control enclosure ecosystem is 51.84~61.96,which indicates that the water is in the mild eutrophication status and the water quality is at mild pollution level.The evaluation results from two water pollution evaluation methods are inconsistent but the results both indicate the water of Taihu Lake is polluted to a certain extent.