2015年淮河干流安徽段浮游植物群落结构特征

Characteristics of Community Structure of Phytoplankton in Anhui section of Mainstream of Huai River in 2015

2015年1月、4月、7月和10月,在淮河干流安徽段的5个重要河口,进行了浮游植物和水环境野外调查,研究了该河段水体的理化性质、浮游植物群落结构组成、浮游植物细胞丰度和生物量的时空分布;利用Shannon-Wiener多样性指数、Simpson指数和Pielou均匀度指数,研究该河段浮游植物多样性;利用Pearson相关分析方法,分析影响浮游植物群落结构的主要环境因子。研究结果显示,共鉴定出浮游植物6门22科35属57种(包括变种),其中,有绿藻门14属23种,占浮游植物物种总数的40.35%;硅藻门9属16种,占28.07%;甲藻门3属3种,占5.26%;蓝藻门4属8种,占14.04%;裸藻门3属4种,占7.02%;隐藻门2属3种;占5.26%。浮游植物优势种为卷曲鱼腥藻(Anabaena circinalis)、颗粒直链藻极狭变种(Melosira granulata var.angustissima)、梅尼小环藻(Cyclotella meneghiniana)和盘星藻(Pediastrum biradiatum)。浮游植物群落结构组成及变化显示,蓝藻门物种的细胞丰度占绝对优势,其次为绿藻门,其相对丰度分别为48.74%、28.37%,其细胞丰度都在7月最大;生物量分析结果显示,绿藻门物种的相对生物量最大,其次为硅藻门物种,相对生物量分别为49.50%和20.11%。该河段浮游植物的总细胞丰度和生物量分别是1 417.42×10~4cells/L和9.410 mg/L。该河段浮游植物群落的Shannon-Wiener多样性指数和Pielou均匀度指数呈现从上游到下游逐渐减小的趋势。Pearson相关分析结果表明,影响浮游植物群落结构的主要因子为水中的溶解氧含量、水温、叶绿素a含量和硝态氮含量等,同时,不同河段的水流流速和采砂船作业、生活船坞的严重干扰也影响了浮游植物的群落结构。与2012年相比,2015年淮河干流安徽段的浮游植物物种数量明显减少,但是以绿藻和硅藻为主的群落结构没有改变。根据浮游植物生态指标的水质现状评价结果表明,淮河干流安徽段的水体污染水平为β-中污染与α-中污染之间水平。该河段蓝藻门物种的细胞丰度最大,表明水体的水质已经恶化。

On January 8, April 13, July 10 and October 13, 2015, the field surveys of water environment in five sampling sites in Anhui section of mainstream of Huai River were carried out to investigate the water physicochemical property, the community structure and abundance of phytoplankton as well as the spatial-temporal distribution of biomass. The biodiversity of phytoplankton in Anhui section was studied through Shannon-Wiener diversity index, Simpson index and Pielou evenness index; and the main environmental factors influencing the community structure of phytoplankton were analyzed by Pearson correlation analysis method.The results showed that a total of 57 species of phytoplankton, belonging to 22 family, 35 genera, 6 phyla, was identified. Among these species, Chlorophyta（14 genera 23 species） was the predominant species, accounted for 40.35% of the total species; Bacillariophyta was recorded 9 genera 16 species, accounted for 28.07%;Dinophyta was recorded 3 genera 3 species, accounted for 5.26%; Cyanophyta was recorded 4 genera 8 species, accounted for 14.04%; Euglenophyta was recorded 3 genera 4 species, accounted for 7.02%, and Cryptophyta was recorded 2 genera 3 species, accounted for 5.26%. The dominant species of phytoplankton were Anabaena circinalis, Melosira granulata var. angustissima, Cyclotella meneghiniana, and Pediastrum biradiatum. In terms of algal population structure composition and variation, Cyanophyta was the most abundant algae, followed by Chlorophyta, accounting for 48.74% and 28.37% of the total cell abundance, respectively;and their cell abundance achieved the maximum level on July 8, 2015. The relative biomass of Chlorophyta was the largest, followed by Bacillariophyta, accounting for 49.50% and 20.11%, respectively. The total cell abundance and biomass of phytoplankton were 1 417.42×10^4 cells/L and 9.410 mg/L, respectively. The Shannon-Wiener diversity index and Pielou evenness index gradually decreased from upstream to downstream in Anhui section. The community structure of phytoplankton in Anhui section was mainly influenced by contents of dissolved oxygen, chlorophyll a, nitrate nitrogen and temperature. Furthermore, water velocity and human activities also influenced the phytoplankton community structure. The water quality in Anhui section of the mainstream of Huai River was in β-moderate to α-moderate pollution status. The fact that Cyanophyta being the dominant phytoplankton species suggested the water quality has already deteriorated.