富春江下游段夏季浮游植物群落结构特征及其与环境因子的关系

Phytoplankton community structure in the downstream section of Fuchun River in summer and its relationship with environmental factors

为探明浮游植物群落结构特征及其与环境因子的关系,于2018年7月(夏季)对富春江下游段水体中的浮游植物开展取样调查。结果显示:浮游植物共99种,隶属6门50属,种类组成表现为硅藻-绿藻型。主要的优势种分别为梅尼小环藻(Cyclotella meneghiniana)、颗粒直链藻(Melosira granulata)、颗粒直链藻最窄变种(M.granulata var.angustissima)、变异直链藻(M.varians)、卵形隐藻(Cryptomons ovata)、微小多甲藻(Peridinium pusillum)和小球藻(Chlorella vulgaris),其中颗粒直链藻最窄变种优势度最大,夏季浮游植物细胞密度为(1.66±0.77)×10~5 ind./L。Margalef多样性指数(D)的变化范围为1.63~3.39,Shannon-Wiener多样性指数(H′)的变化范围为2.09~3.16,Pielou均匀度指数(J′)的变化范围为0.65~0.86;Simpson多样性指数(λ)的变化范围为0.75~0.93。相关性分析和CCA分析结果显示,总氮和硝态氮是影响富春江下游江段夏季浮游植物最主要的环境因子。

A sampling survey was conducted on the phytoplankton in the downstream section of the Fuchun River in July 2018 to explore the structural characteristics of the phytoplankton community.The results showed that there were 99 speciesof phytoplankton,belonging to 6 phyla and 50 genera,and the species composition was diatom-green algae.The maindominant species were Cyclotella meneghiniana,Melosira granulata,M.granulata var.angustissima,M.Varians,Cryptomons ovata,Peridinium pusillum and Chlorella vulgaris.Among them,the M.granulata var.angustissima had the greatest dominance.The average density of summer phytoplankton cells at each sampling point was(1.66±0.77)×105 ind./L.Margalef diversity index ranged from 1.63 to 3.39,Shannon-Wiener diversity index ranged from 2.09 to 3.16,and Pielou uniformity index ranged from 0.65 to 0.86.The diversity index Simpson ranged from 0.75 to 0.93.The correlation analysis and CCA analysis results showed that the most critical environmental factors affecting phytoplankton in the lower reaches of the Fuchun River were total nitrogen and nitrate nitrogen in summer.