摘要
本文报道了东湖Ⅰ、Ⅱ站1974—1975,1979—1980四个周年浮游动物种类组成和现存量的调查结果。束湖浮游动物的种类在减少,Ⅰ、Ⅱ站间种类组成的差别亦在缩小。浮游动物现存量的总趋势为逐渐增加。年数量变动曲线一般有夏季和秋季两个高峰,秋季高峰比夏季高峰更为突出。浮游动物总数的消长完全受原生动物数量的支配。年生物量的变动曲线不甚规则,不同的年份,Ⅰ、Ⅱ站均有所不同,以冬、春两季的生物量较高。四年年平均生物量统计结果:Ⅰ站原生动物占浮游动物总量的18.93%,轮虫占25.25%,枝角类占46.02%,桡足类占9.80%;Ⅱ站原生动物占总量的13.92%,轮虫占15.24%,枝角类占58.93%,桡足类占11.91%。本文还对影响浮游动物现存量变动的生态因子进行了讨论。
This paper embodies the results of zooplankton survey made in 1974—1975 and 1979—1980, in lake Donghu, Hubei Province.Samples were collected monthly at two sampling stations. The species number of the zooplankton in 1974—1975 and 1979—1980 was smaller than in 1963; The difference of the zooplankton community between station Ⅰ and station Ⅱ diminished.In general, the standing crop of zooplankton was increased. In the pattern of seasonal fluctuation of zooplankton abundance the peaks were usually recorded in autumn and summer, with the former peak far exceeding the latter.The protozoan number was very high—about 85.5% on average in number of the total zooplankton.On the basis of biomass, the winter and spring peaks were usually observed. The annual averages of the standing crop (1974—1975, 1979—1980) for the four groups of zooplankton were as follows: station Ⅰ: Protozoa, 18.93% of total biomass; Rotatoria, 25.25%, Cladocera, 46.02%; Copepoda, 9.80%; Station Ⅱ: Protozoa, 13.92% of total biomass; Rotatoria, 15.24%, Cladocera, 58.93% Copepoda, 11.91%.The relationships between the seasonal changes and the ecological factors are discussed.
