松花江干流2014~2019年夏季着生藻类群落结构特征及其对环境因子的响应

Periphytic Algae Community Structure and Its Relation to Environment Factors in the Main Stream of the Songhua River from 2014 to 2019

着生藻类的群落特征常被用作评价水生态环境质量的重要指标.通过对2014~2019年夏季松花江干流着生藻类的群落结构特征及其对环境因子的响应关系分析,对松花江干流的水生态环境质量状况及变化趋势进行探讨.结果表明,2014~2019年夏季松花江干流共鉴定着生藻类4门和58属.其中硅藻门28属、绿藻门17属,蓝藻门10属和裸藻门3属.流域主要组成物种为硅藻门、绿藻门和蓝藻门,分别占总数48.28%、29.31%和17.24%.着生藻类细胞密度平均值为4.35×10^(4)ind·cm^(-3),变化范围在1.29×10^(4)~8.42×10^(4)ind·cm^(-3)之间,优势属主要为硅藻门小环藻属(Cyclotella)、直链藻属(Melosira)、星杆藻属(Asterionella)、桥弯藻属(Cymbella)、针杆藻属(Synedra)、羽纹藻属(Pinnularia)、舟形藻属(Navicula)和绿藻门的栅藻属(Scenedesmus)等.分析松花江干流水环境质量演变趋势,溶解氧含量逐年升高,氨氮、总磷和总氮含量呈先升高后下降趋势,2019年水体改善效果显著.运用冗余分析(RDA)探究着生藻类与环境因子间的变化关系,发现驱动松花江干流着生藻类群落结构演替的主要环境因子随时间推移而有所变化,溶解氧、氨氮、总氮、总磷和生化需氧量等指标是这一区域着生藻类种类分布的重要环境影响因子.

Periphytic algae are often used as an indicator to evaluate water quality.Here,the community structure of periphytic algae and its relationship with environment factors were analyzed in the main stream of the Songhua River during the summers of 2014 to 2019.The status and trends in ecological water quality were also evaluated based on bioassessments.Phytoplankton species belonging to 4 phyla and 58 genera were recorded,including 28 Bacillariophyta genera,17 Chlorophyta genera,10 Cyanophyta genera,and 3 Euglenophyta genera;Bacillariophyta,Chlorophyta,and Cyanophyta accounted for 48.28%,29.31%,and 17.24%of the community,respectively.Cell densities varied between 1.29×10^(4)and 8.42×10^(4)ind·cm^(-3),with an average of 4.35×10^(4)ind·cm^(-3).The dominant genera were Cyclotella,Melosira,Asterionella,Cymbella,Synedra,Pinnularia,Navicula,and Scenedesmus.The physicochemical water quality showed notable changes during the past six-year monitoring period.Specifically,the dissolved oxygen content increased year on year;ammonia nitrogen,total phosphorus,and total nitrogen first increased and then decreased;and,overall,water quality significantly improved in 2019.Relationship between periphytic algae and environmental factors was further examined using redundancy analysis(RDA),which showed that time was the main factor driving the succession of algal community structure.Dissolved oxygen(DO),ammonia nitrogen(NH_(4)^(+)-N),total nitrogen(TN),total phosphorus(TP),five-day biochemical oxygen demand(BOD),and chemical oxygen demand(COD)were also important environmental variables affecting algal community structure.