拉萨河流域浮游植物群落结构特征及与环境因子的关系

于2017年8月对拉萨河浮游植物群落组成、丰度、功能群以及多样性指数进行调查,利用典范对应分析法(CCA)分析浮游植物物种与水环境因子的关系。结果表明:流域种类组成以硅藻门(60.4%)为主,其次是绿藻门(20.8%),其余种类18.8%;物种平均丰度为3857cells/L,硅藻门94.6%,蓝藻门3.1%,绿藻门2.3%;种类少、丰度低是拉萨河流域浮游植物群落结构的主要特征;研究区优势种以菱形藻为主; MP、D和P是划分出来的15类功能群中的优势功能群,合计占总丰度的93%,剩余12类仅占7%; Margalef指数、Shannon-Wiener指数及Pielou's evenness指数平均值分别为1.41、1.77和0.5,单因素方差分析(ANOVA)表明三类多样性指数在各支流之间、干流与各支流之间无显著差异; CCA排序结果表明:p H、化学需氧量(CODCr)、总氮(TN)、总磷(TP)是影响拉萨河流域浮游植物群落结构的主要环境因子;同时,pH、TN、TP也是影响浮游植物功能群分布格局的主要因子。

Community structures of phytoplankton and its relationship with environmental factors in the Lhasa River

An investigation was conducted on the phytoplankton community structure, abundance, functional groups, and diversity indices in the Lhasa River in August 2017; subsequently, canonical correspondence analysis (CCA) was used to study its relationships with environmental factors. The results showed that Bacillariophyta (60.4%) was the dominant phytoplankton, the second was Chlorophyta (20.8%), and the remaining 18.8% was composed of a variety of species. The average abundance was 3857 cells/L; Bacillariophyta, Cyanophyta, and Chlorophyta accounted for 94.6%, 3.1%, and 2.3%, respectively. Few species and low abundance are special characteristics of the phytoplankton community structure in the Lhasa River. The most dominant species of phytoplankton was Nitzschia sp. In total, 15 types of phytoplankton functional groups were identified:MP, D, and P were dominant, comprising 93% of all groups, with other phytoplankton functional groups accounting for the remaining 7%. The diversity indices of Margalef, Shannon-Wiener, and Pielou''s evenness were 1.41, 1.77, and 0.5, respectively. The diversity index was not significantly different between the main stream and branches when analyzed using one-way analysis of variance. CCA indicated that the pH, chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) were the main environmental factors that influenced phytoplankton assemblages and that pH, TN, and TP were the main environmental factors that influenced the functional groups.