金沙江上游苏洼龙水电站建设期影响区域浮游植物群落结构与水质现状分析

为了了解金沙江上游苏洼龙水电站建设期影响区域浮游植物群落结构与水质现状,为库区形成后区域性水生态保护措施的制定提供理论依据,于2019年5月(平水期)和8月(丰水期),对影响区域内的5个采样点进行浮游植物及水质调查,并作相关性分析。结果显示:2次调查共采集到浮游植物4门31属88种,其中硅藻门为绝对的优势类群,共79种,蓝藻门5种,绿藻门3种,裸藻门仅1种。主要优势种为细等片藻(Diatoma tenue)、念珠等片藻(D.moniliforme)、极细微曲壳藻(Achnanthes minutissima)和小内丝藻(Encyonema minutum);硅藻细胞密度在0.05×10⁶~0.20×10⁶ cells/L变化,平均值为0.11×10⁶ cells/L。浮游植物Shannon-wiener多样性指数(H)、Margalef丰富度指数(D_ma)和Pielou(J)均匀度指数变化范围分别为2.05~2.90、0.83~1.96和0.82~0.91。根据浮游植物细胞密度及生物多样性指数综合评价,金沙江苏洼龙段水质为轻污染极贫营养型。Pearson相关性分析结果显示,水温、电导率、盐度、总氮和磷酸盐是影响该河段浮游植物群落结构变化的主要环境因子。

Phytoplankton community structure and water quality status in upper reaches of Chin-sha River affected by Constructing Suwalong hydropower station

To understand the phytoplankton community structure and water quality status in the affected region of upper Chin-sha river during the construction of Suwalong hydropower station,and to provide theoretical basis for regional water ecological protection after reservoir inpoundment,we carried out phytoplankton and water quality investigation at 5 sampling sites in the affected region in May(normal water season)and August(wet season)of 2019,and the correlation of phytoplankton community and the water quality indicators were analyzed.Results were as follows:A total of 88 phytoplankton species from 31 genera and 4 phyla were collected during the two surveys,with the absolute dominance of diatoms(79 species),followed by cyanobacteria(5 species),chlorophyta(3 species)and euglenophyta(1 species).The dominant species were Diatoma tenue,Diatoma moniliforme,Achnanthes minutissima,and Encyonema minutum.The range of diatom cell density was 0.05×10⁶~0.20×10⁶ cells/L,with the average value of 0.11×10⁶ cells/L.The Shannon-wiener diversity(H),Margalef richness(D_ma)and Pielou evenness(J)indices of phytoplankton community ranged from 2.05 to 2.90,0.83 to 1.96 and 0.82 to 0.91,respectively.Comprehensive evaluation based on phytoplankton cell density and community biodiversity shows that the water quality in Suwalong section of Chin-sha River was oligotrophic with light pollution.Pearson correlation analysis shows that water temperature,conductivity,salinity,total nitrogen and phosphate were the main environmental factors affecting the phytoplankton community structure in the surveyed river reach.