永定河上游流域浮游植物变化及水质状况分析

Analysis of changes in phytoplankton and water quality in the upper reaches of the Yongding River

基于采样数据分析,对永定河上游流域浮游植物进行定性定量研究。结果显示,调查期间研究区共鉴定出浮游植物8门226种(含变种和变型),优势种为硅藻门,占藻类总种数的42.03%。浮游植物丰度和生物量季节变化明显,浮游植物丰度最大值出现在夏季,为26.10×10^6 ind·L^-1,最小值出现在春季,为13.64×10^6 ind·L^-1;浮游植物生物量最大值出现在夏季,为53.06 mg·L^-1,最小值出现在秋季,为11.37 mg·L^-1。水质评价结合浮游植物生物评价的结果表明,17个采样点的水质整体处于中污染状态。因此,永定河上游流域需要加大力度治理洋河、清河流域的点源和面源污染,降低水体中的氮含量以及官厅水库水体富营养化程度,保护水库生态系统健康。

Sampling was conducted in April(spring),July(summer),and October(autumn)2019 to perform a qualitative and quantitative study on phytoplankton in the Guanting Reservoir and the upper reaches of the Yongding River.During the survey,a total of 226 species(including varieties and variants)of eight phytoplankton phyla were identified,and the dominant species were in the diatom clade,accounting for 42.03%of the total species of phytoplankton.Phytoplankton abundance and biomass showed significant seasonal changes.The highest phytoplankton abundance(26.10×10^6 ind·L^-1)was recorded in summer,whereas the lowest phytoplankton abundance(13.64×10^6 ind·L^-1)was recorded in spring.The highest phytoplankton biomass(53.06 mg·L^-1)was recorded in summer,and the lowest phytoplankton biomass(11.37 mg·L^-1)was recorded in autumn.The results of the evaluation of the water quality combined with the evaluation of biological characteristics of phytoplankton indicate d that the water quality of the basin was relatively good in summer and autumn,but poor in spring,and the overall water quality of the 17 sampling sites was considered to be moderately polluted.The results of redundancy analysis(RDA)indicate that total nitrogen(TN)and nitrate nitrogen(NO3-N)played an important role in promoting the growth of dominant species of phytoplankton.We believe that the upstream region of the Yongding River in the Guanting Reservoir is the point source and non-point source of pollution in the reservoir basin,and in the Yanghe River basin and Qinghe River basin.Efforts should be made to reduce the N concentration in the water to control the degree of eutrophication of the water in the Guanting Reservoir,and protect the health of the reservoir ecosystem.