淀山湖后生浮游动物群落结构特征分析

Study on meta-zooplankton community structure of Dianshan Lake

于2008年10月至2009年10月对淀山湖浮游动物的群落结构组成及现存量进行了调查研究.共鉴定浮游动物80种,其中轮虫46种(58%),枝角类21种(26%),桡足类13种(16%),优势种主要为螺形龟甲轮虫(Keratella cochlearis)、矩形龟甲轮虫(Keratella quadrata)、曲腿龟甲轮虫(Keratella valga)、萼花臂尾轮虫(Brachionus calyciflorus)、裂足臂尾轮虫(Brachionusdiversicornis)、长额象鼻溞(Bosmina longirostris)、简弧象鼻溞(Brachionus coregoni)、微型裸腹溞(Moina micrura)、广布中剑水蚤(Microcyclops leuckarti)、球状许水蚤(Schmackeria forbesi)和汤匙华哲水蚤(Sinocalanus dorrii).淀山湖浮游动物的月平均密度为(356±334)ind./L,最高值出现在2009年5月,为1 260 ind./L,最低值出现在2008年12月,为52ind./L;淀山湖浮游动物的月平均生物量为(12.67±12.53)mg/L,最高值出现在2009年7月,为40.85 mg/L,最低值为2008年12月的1.45 mg/L.水平分布上,浮游动物周年年均生物量在S11(水产养殖场)最高,生物密度和生物量分别达208 ind./L和22.77 mg/L,S9(威尼斯别墅段)样站年平均密度最低,为208 ind./L;年平均生物量最低点出现在S7站位,仅为6.91 mg/L.淀山湖浮游动物Shannon-Wiener物种多样性指数(H)变动在0.841～2.187之间,平均为1.718,采用生物多样性指数法对水质状况进行初步评价,结果显示淀山湖水体总体呈现α-中污型污染程度.

The investigation of the community structure of zooplankton in Dianshan Lake was undertaken monthly during October 2008 to October 2009,including species composition,standing crop dynamics and diversities.A total of 80 metazooplanton species including 46 Rotifera（58%）,21 Cladocera（26%） and 13 Copepoda（16%） were encountered.The dominant species were five species of rotifera（Keratella cochlearis,Keratella quadrata,Keratella valga,Brachionus calyciflorus and Brachionus diversicornis）,three species of copepod（Microcyclops leuckarti,Sinocalanus dorrii and Schmackeria forbesi） and two other species of cladocera which showed a trend of miniaturization（Bosmina longirostris,Brachionus coregoni and Moina micrura）.The zooplankton mean density was 356±334 ind./L and ranged from 52 ind./L in May 2009 to 1260 ind./L in December 2008,and the zooplankton average biomass was 12.67±12.53 mg/L,with the highest value in July 2009 and lowest in December 2008,which was 40.85 mg/L and 1.45 mg/L respectively.Regarding the distribution of the sampling sites,the highest values of the yearly mean density and biomass both appearred in Site 11,and the lowest density in Site 9 with the lowestbiomass in Site 7,respectively.The value of Shannon-Wiener index（H） in Dianshan Lake fluctuated between 0.841 and 2.187,with 1.718 as average.Upon the evaluation of biological diversity index,the water quality of Dianshan Lake could be regarded as α mesosaprobity according to the results analysis.