青藏高原可鲁克湖浮游动物群落结构特征及水质评价

摘要

Zooplankton community structure including seasonal change in zooplankton biodiversity and standing crop and main water physicochemical indicators were investigated in Keluke Lake in July (summer) and October (autumn) of 2013,January(winter) and April(spring) of 2014 and water quality was assessed by biodiversity in-dex and plankton biomass evaluation standard to understand the characteristics of zooplankton community structure and the state of the water quality in Keluke Lake,and to scientifically protect the plateau lake ecological health.To-tal of 82 zooplankton species belonging to 48 genera were identified, including 16 species of protozoa, accounting for 19.51%,57 species of rotifers,representing 69.51%,7 species of cladocera,accounting for 8.54%,and 2 spe-cies of copepods,accounting for 2.44%,with dominant rotifers in the species composition. There were 3 dominant species in spring,7 in summer,4 in autumn and 6 in winter, Keratella cochlearis and Polyarthra trigla being the common dominant species in four seasons. The annual density of zooplankton was ranged from 2.7 ind./L to 2756 ind./L with an average of 539.8 ind./L,and the annual biomass was varied from 0.03 mg/L to 3.256 mg/L with an average of 0.680 mg/L.There was significant difference in zooplankton standing crop in four seasons(P<0.05) and clustering analysis based on zooplankton density revealed that zooplankton in every sampling site was divided into two groups in spring and winter,four groups in summer,and three groups in autumn,with mean Shannon index of 1.97,Margelef index of 0.74 and Pielou index of 0.54. The zooplankton ecology comprehensive index indicated that the water quality in Keluke Lake was in pollution,with oligotrophic water in three seasons,and mesotrophic water in only spring,showing that it is necessary to take active measurements to strengthen water quality management and control.%为了解可鲁克湖浮游动物群落结构特征及水质状况,分别于2013年7月 (夏季) 和10月 (秋季)、2014年1月 (冬季) 和4月 (春季) 调查了青海可鲁克湖浮游动物群落结构和主要的水体理化指标,分析了该湖泊浮游动物现存量和多样性的季节变化规律,并利用生物多样性指数和浮游生物生物量评价标准对水质状况进行评价.结果表明:可鲁克湖全年共检出浮游动物48属82种,其中,原生动物16种(占总种类数的19.51%),轮虫57种 (占69.51%),枝角类7种 (占8.54%),桡足类2种 (占2.44%);种类组成以轮虫占优势,春季、夏季、秋季、冬季优势种分别为3、7、4、6种,4个季节共有的优势种有2种,为螺形龟甲轮虫Keratella cochlearis和针簇多肢轮虫Polyarthra trigla;浮游动物年平均密度为539.8 ind. /L,变化范围为2.7~2756.0 ind. /L,年平均生物量为0.680 mg/L,变化范围为0.030~3.256 mg/L, 4个季节浮游动物现存量有显著性差异 (P<0.05);聚类分析显示,可鲁克湖春冬季各采样点浮游动物分为2大类群,夏季分为4大类群,秋季分为3大类群;香浓多样性指数 (H′)、丰富度指数 (M)、均匀度指数 (J) 年平均值分别为1.97、0.74、0.54.根据浮游动物生态学指标总体评价,可知可鲁克湖水质处于污染状态,且4个季节中有3个季节水体属于贫营养类型,只有春季属于中营养类型,应采取积极措施加强水质监管与调控.