秋香江冬季水质现状及浮游生物群落结构特征

Water Quality Status and Plankton Community Structure Characteristics in Qiuxiang River in Winter

【目的】调查秋香江上游、中游和下游3个水电站6个监测断面的水环境因子、浮游生物组成等,阐明秋香江的水生态现状。【方法】分别利用综合营养状态指数、生物多样性指数和冗余分析,调查水质现状、浮游生物的群落结构特征及两者间的关系。【结果】秋香江水体透明度为0.32~0.53 m,叶绿素a含量为0.10~0.43 mg/L,总磷含量为0.6~5.3 mg/L,总氮含量为1.39~4.33 mg/L,高锰酸盐浓度为0.70~3.90 mg/L,综合营养状态指数表明秋香江水体现处于中营养状态水平;共鉴定出53种浮游植物和62种浮游动物,浮游植物密度和浮游动物丰度范围分别为5.1×10^(8)~1.89×10^(9) cells/L和3.93~232.87 ind/L,其中绿藻、硅藻、蓝藻、原生动物和轮虫为优势种;综合浮游生物的多样性指数来看,秋香江属于中污染水平。【结论】秋香江上游受到了一定程度的污染,沿着河流方向污染程度减小,溶解氧是影响秋香江浮游生物群落结构的关键环境因子。

【Objective】The water environment factors and plankton compositions of six monitoring sections at 3 hydropower stations along the upstream,midstream and downstream of the Qiuxiang River were investigated,and the water ecological status of the Qiuxiang River was clarified.【Method】The comprehensive nutritional status index,biodiversity index and redundancy analysis were used to analyze the water quality status,the community structure characteristics of plankton and the relationship between them,respectively.【Result】The water transparency,concentrations of Chla,total phosphorus,total nitrogen and permanganate were 0.32-0.53 m,0.10-0.43 mg/L,0.6-5.3 mg/L,1.39-4.33 mg/L and 0.70-3.90 mg/L,respectively.The water quality status of the Qiuxiang River was at medium nutrition level according to the comprehensive nutritional state index.A total of 53 species of phytoplankton and 62 species of zooplankton were identified.The abundance of the phytoplankton was ranged from 5.1×10^(8) to 1.89×10^(9) cells/L and that of the zooplankton was ranged from 3.93 to 232.87 ind/L.Chlorophyta,Bacillariophyta,Cyanophyta,Protozoa and Rotaria were the dominant species among phytoplankton and zooplankton.Based on the comprehensive plankton diversity index,the pollution of Qiuxiang River was at the medium level.【Conclusion】The upper reaches of the Qiuxiang River has been polluted to a certain extent,and the degree of pollution along the river is reduced.Dissolved oxygen is a key environmental factor affecting the structure of the plankton community in the Qiuxiang River.