乌江流域浮游植物群落结构的特征

Community Structure Characteristics of Phytoplankton in Wujiang River

2007年7月和10月对乌江流域的浮游植物进行两次调查,研究其浮游植物种类组成、数量变化特征及与水环境因子的相关性,评价乌江的水质现状,探讨水电开发对浮游植物群落结构的影响。结果表明:乌江共检出浮游植物计7门75属156种,其中硅藻门68种,占检出种类的43.6%;绿藻门55种,占35.3%;蓝藻门22种,占14.1%,裸藻门4种,占2.6%;甲藻门、隐藻门各3种,分别占1.9%;金藻门1种,占0.6%。浮游植物密度均值为1.013×106个/L,生物量均值为0.4437 mg/L,多样性指数均值为2.25,均匀度指数均值为0.65。相关性分析结果表明:浮游植物生物量和密度与溶氧呈显著负相关(P<0.05),与透明度呈显著正相关(P<0.01)。依据藻类生物学指标评价标准,乌江水质为贫-中营养类型。

Species composition, density and biomass of phytoplankton in Wujiang River were investigated in July and October, 2007.The correlations of the density and biomass of phytoplankton with water environment factors were analyzed. In addition, the water quality in Wujiang Rive was evaluated to investigate the impacts of hydropower development on the phytoplankton community structure.The total of 156 species belonging to 75 genera for phytoplankton was recorded, of which, 68 species in Bacillariophyta, accounted for43.6%; 55 species in Chlorophyta, 35.3%; 22 species in Cyanophyta, 14.1%; 4 species in Euglenophyta, 2.6%; 3 species in Chrysophyta and 3 species Pyrrophyta, 1.9%, respectively; and 1 species in Chrysophyta, 0.6%. The phytoplankton was found at a density 1.013 ×106ind/L and biomass of 0.4437 mg/L with the Shannon-Wiener index of 2.25 and Pielou index of 0.65. The correlation analysis revealed that there was significantly negative correlation between biomass and density of phytoplankton and dissolved oxygen levels(P<0.05), and very significantly positive correlation between biomass and density of phytoplankton and transparency(P<0.01). According to the evaluation standards of algal biology indexes, the water quality in Wujiang River belongs to mesotrophic-oligotrophic type.