Variation of Phytoplankton Community and Water Quality Assessment Before and After Pollution Control in the Upper Reaches of Xiaoqing River
In order to study the variation of phytoplankton community and water quality before and after pollution control in the upper reaches of Xiaoqing River,samples were collected in 2015(before pollution control)and 2020(after pollution control)respectively.The phytoplankton species decreased from 35 species of 6 phyla in 2015 to 31 species of 4 phyla in 2020.The paired sample T-test showed that the species and density were significantly changed,with the relative abundance of diatom and green algae increasing by 51.6 percentage points and 13.3 percentage points respectively,while that of cyanobacteria decreasing by 62.9 percentage points.Cyclotella spp.replaced Microcysitis spp.as the dominant species,and the community changed from cyanobacteria to diatoms.Similarity analysis(ANOSIM)and similarity percentage analysis(SIMPER)showed that the community characteristics changed significantly.The results of non-metric multidimensional scaling analysis(NMDS)showed that the community characteristics of S2 and S3 were different after treatment,and the community characteristics of S4 and S1 tended to be similar.Redundancy analysis(RDA)showed that the effects of TP and DO on phytoplankton community were significantly weakened after pollution treatment,while TN,NH3-N and pH were the main physicochemical indexes affecting the community structure.The influence of N and P pollution on phytoplankton was reduced from S2-S4 reach to S2 reach.There were significant differences in Shannon-Wiener diversity index(H′),Pielou evenness index(J)and Marglef richness index(d)before and after treatment.After treatment,the upper reaches of Xiaoqing River were still in a state of alpha-pollution,but the river water quality had been significantly improved.
NETL
NSTL
万方数据
维普
