宁夏沙湖浮游植物群落结构及多样性研究

Community Structure and Biodiversity of Phytoplankton in Shahu Lake,Ningxia

于2008年4月-2009年1月对宁夏沙湖浮游植物的种类组成、密度、生物量、优势种以及物种多样性进行了分析研究,并依据浮游植物种类组成和密度,对浮游植物群落结构进行了聚类分析（Cluster Analysis,CA）和多维分析（Multidimensional scaling,MDS）。结果表明,沙湖浮游植物共有8门94属117种,种类构成比例为绿藻49.6%、硅藻21.6%、蓝藻16.0%和其它12.8%。春季优势种的种类较多,蓝、硅、绿藻均有,夏、秋季蓝藻占绝对优势,冬季以绿藻为主。浮游植物种类、密度、生物量和分布依季节而异,高峰期出现在7月,低谷期出现于1月。Margalef指数2.872~4.652,Shannon指数2.058~3.057,均匀度指数0.521~0.759,综合评价沙湖水体为中富营养水平。浮游植物群落结构春、夏、冬季聚为3类,秋季聚为2类,除春季外,MDS分析结果和聚类分析结果一致,支持和证实了聚类分析的结果,很好地揭示了沙湖各季节、各样点间浮游植物群落结构的相似性与差异性。

Based on the data in Shahu Lake in Ningxia province from Apr.2008 to Jan.2009,the species composition,phytoplankton density,phytoplankton biomass,seasonal variation and dominate species of the phytoplankton were discussed.Phytoplankton communities were studied by Cluster analysis and Multidimensional scaling.8 phyla,94 genera and 117 species of phytoplankton community in Shahu Lake were identified.The proportion of the community composition was Chlorophyta 49.6%,Bacillariophyta 21.6%,Cyanophyta 16.0%,and others 12.8%.The dominant species were some species of Cyanophyta,Bacillariophyta,Chlorophyta in spring.Some species of Cyanophyta were the absolute dominant species in summer and autumn.The dominant species were some species of Chlorophyta in winter.The composition and distribution of the phytoplankton in Shahu Lake was different according to the variation of seasons.The seasonal variation of the phytoplankton in Shahu Lake was that the highest peaks appeared in July,and the lowest peaks appeared in January.Margalef index is between 2.872-4.652,Shannon index is between 2.058-3.057,Evenness index is between 0.521-0.759.The water body of Shahu Lake was near to medium eutrophication.The 5 stations can be separated into three groups in spring,summer,winter,and two groups in autumn by the cluster analysis based on the species composition.The results of cluster analysis were supported and confirmed by multidimensional scaling in each season but for spring,and showed the similarity and differences of each season and each station in Shahu Lake.