程海浮游动物种群特征与数量的周年变化

Annual Changes of Population Characteristics and Quantities of Zooplankton in Chenghai Lake

为深入了解程海湖泊生态系统的状况,2009年10月至2010年7月对程海浮游动物进行了季节性调查。结果表明,程海有浮游动物34科、59属、86种;其中,原生动物13科、18属、28种,轮虫10科、23属、34种,枝角类5科、7属、11种,桡足类2科、7属、9种,其他浮游动物4科、4属、4种。原生动物纤毛虫类(Ciliophora)四季均为优势类群,溞钟虫(Vorticella kahli)春季数量较多,而急游虫(Strombidium sp.)和湖累枝虫(Epistylis lacustris)在秋季数量达到高峰。轮虫优势种为暗小异尾轮虫(Trichocerca pusilla)、奇异巨腕轮虫(Pedalia mira)、裂痕龟纹轮虫(Anuraeopsis flasa)和萼花臂尾轮虫(Brachionus calyciflorus)。枝角类种类少、数量多,主要是棘爪网纹溞(Ceri-odaphnia reticulata)、短尾秀体溞(Diaphanosoma brachyurum)、透明溞(Daphnia hyaline)、园形盘肠溞(Chydorus sphaericus)和长肢秀体溞(D.leuchtenbergianum);桡足类种类少、数量低,近剑水蚤(Tropocyclops sp.)、锯齿真剑水蚤(Eucyclops macruroides deticulatus)、透明温剑水蚤(Thermocyclops hyalinus)常见并有一定优势。浮游动物数量为3316.9个/L;其中,春季2635.6个/L,夏季3010.7个/L,秋季3998.0个/L,冬季3623.5个/L;水平分布南部明显偏高,东部数量高于西部,湖心明显偏少。相关分析表明,影响浮游动物数量变动的主要因子是温度、食物和鱼类摄食。在水体富营养化和太湖新银鱼(Neosalanx taihuensis)的强大摄食压力下,程海浮游动物小型化趋势明显。

A study was carried out on the zooplankton in Chenghai Lake from October 2009 to July 2010, in order to get a better understanding of the status of its lake ecological system. The results show that there are 86 species of the zooplankton in Chenghai Lake, which belong to 59 genera and 34 families. Among these, they are the protozoan of 28 species, belonging to 18 genera and 13 families; the rotifers of 34 species, belonging to 10 families and 23 genera; the cladocera of 11 species, belonging to 7 genera and 5 families; the copepods of 9 species, belonging to 7 genera and 2 families; and the other zooplankton of 4 species, belonging to 4 genera and 4 families. Ciliophora is the dominant species throughout the year. Vorticella kahli is in a larger number in springs, while the number of Strombidium sp. and Epistylis lacustrisis reaches the peak in autumns. Trichocerca pusilla sp., Pedalia mira, Anuraeopsis flasa and Brachionus calyciflorus are the dominant species of rotifers. The species of Cladocera are less and its quantities are large, wihch mainly are Ceriodaphnia reticulate, Diaphanosoma brachyurum, Daphnia （Daphnia） hyaline, Chydorus sphaericus and D. leuchtenbergianum. The copepods also have less species and small quantities, with Tropocyclops sp., Eucyclops macruroides deticulatus and Thermocyclops hyalinus being frequently observed and dominant. The quantity of these individuals is 3 316.9 ind./L, which 2 635.6 ind./L in the spring, 3 010.7 ind./L in the summer, 3 998.0 ind./L in the autumn and 3 623.5 ind./L in the winter. As for the horizontal distribution, the quantities in the southern lake are relatively high, and the eastern part has more individuals than the western part of the lake. It is much less in the center of the lake. Correlated analysis indicates that temperature, food and fish ingestion are the main factors to affect the quantity changes in the zooplankton. The trend of zooplankton miniaturization is obvious with the water eutrophication and the big ingestion pressure from Neosalanx taihuensis.