淀山湖原生动物种类组成及数量变动

Species composition and abundance variation of protozoa in Dianshan Lake

应用淡水浮游生物调查方法,查明了2004—2006年淀山湖浮游原生动物的种类组成及数量变动,并研究了原生动物数量变动、Margalef多样性指数与水体富营养化的关系,以期为淀山湖湖泊水质管理提供基础的生物资料。共鉴定原生动物(仅肉足虫类和纤毛虫类)48种,隶属33属7目,其中肉足虫10种、纤毛虫38种;优势种为淡水筒壳虫(Tin-tinnidium fluviatile Stein)、恩茨筒壳虫(T.entzii Chiang)、绿急游虫(Strombidium viride Stein)、小单环栉毛虫(Didinium balbiamii nanum Kahl)及钟形钟虫(Vorticella companula Ehrenberg),优势种密度之和最高可占总密度的69.8%;3年原生动物年均密度季节变化,春季(7685ind.L-1)>冬季(3241ind.L-1)>秋季(2153ind.L-1)>夏季(1680ind.L-1);水平变化表现为村落周边St2站点(4405ind.L-1)和进水口St5站点(4976ind.L-1)居高;原生动物密度水平分布与修正的卡尔森营养综合指数变动趋势基本一致;Mar-galef多样性指数(D)均值为1.45,变幅为1.15～1.99;D值变化与水质状况密切相关。

By using the survey method for freshwater plankton, the species composition and abundance variation of protozoa in Dianshan Lake in Shanghai was investigated from 2004 to 2006, and the relationships between protozoan density, Margalef diversity index, and lake water eutrophication were studied. A total of 48 species belonging to 33 genera of 7 orders were identi- fied, including 10 Sarcodina species and 38 Ciliata species. The dominant species were Tintinnidium fluviatile Stein, T. entzii Chiang, Strombidium viride Stein, Didinium balbiamii nanum Kabl, and Vorticella companula Ehrenberg, and the sum of the dominant species densities accounted for 69. 8% of the total protozoan density. The annual average abundance of protozoa in 2004, 2005, and 2006 was 3365, 5298, and 2549 ind ·L^-1, respectively, and the seasonal fluctuation in the annual average density of protozoa in the three years was shown as spring （7685 ind· L^-1） 〉 winter （3241 ind · L^-1） 〉 autumn （2153 ind· L^-1） 〉 summer （1680 ind·L^-1 ）. Two sampling sites （ St2 and St.5 ） near the villages had the higher densities of protozoa, and the horizontal distribution of protozoan density was consistent with that of modified Carlson trophic state index. The Margalef index ranged from 1.15 to 1.99, with an average of 1.45, which was closely related with water quality.