Phytoplankton community structure and water quality assessment of Hejiang River, a branch of Xijiang River, Pearl River drainage basin

Abstract

为了解珠江流域西江支流贺江浮游藻类的分布并评价其水质情况,于2013年丰水期和枯水期对贺江的浮游藻类群落结构进行调查和分析,结果表明:调查期间共检出浮游藻类7门130种,其中丰水期7门63种,枯水期5门103种,浮游藻类群落组成以绿藻门、硅藻门和蓝藻门为主,丰水期绿藻门居多,硅藻门次之,藻细胞丰度平均值为2.13×10⁶cells/L;枯水期硅藻门最多,藻细胞丰度平均值为3.71×10⁶cells/L;优势种主要有水华微囊藻、卷曲鱼腥藻、小颤藻、啮蚀隐藻、短小舟形藻、变异直链藻、颗粒直链藻、四尾栅藻、集星藻、小球衣藻和小球藻.RDA分析表明,影响贺江浮游藻类群落分布的主要环境因子是氮、磷营养盐,综合营养状态指数显示贺江处于中营养水平.;To study the distribution of phytoplankton and evaluate water quality of Hejiang River, a branch of Xijiang River, Pearl River drainage basin, the community structure of phytoplankton was investigated and analyzed in wet and dry seasons in 2013.The results showed that a total of 130 species belonging to seven phyla of phytoplankton was identified.Including 63 species of seven phyla in wet season and 103 species of five phyla in dry season, phytoplankton community structure in Hejiang River was represented by Chlorophyta, Bacillariophyta and Cyanophyta.Chlorophyta was dominant in wet season, followed by Bacillariophyta.The mean value of phytoplankton density was 2.13×10⁶ cells/L.Bacillariophyta dominated the phytoplankton in dry season, and the mean value of phytoplankton density was 3.71×10⁶cells/L.The dominant species were Microcystis flos-aquae, Anabaena circinalis, Oscillatoria tenuis, Cryptomonas erosa, Navicula exigua, Melosira varians, Melosira granulata, Scenedesmus quadricauda, Actinastrum hantzschii, Chlamydomonas microsphaera and Chlorella valgaris.Based on RDA analysis, nitrogen and phosphorus were important environmental factors that affected the distribution of phytoplankton in Hejiang River.The river was classified as mesotrophic according to comprehensive trophic state index.