Investigation On Water Quality And Spatial-Temporal Distribution Of Algae Community In Qingshan Reservoir And Its Influencing Factors

Qingshan Reservoir is one of the drinking water sources in Hangzhou.and its water quality is affected by domestic sewage,industry,agriculture and tourism.In recent years,there have been many algae outbreaks in Qingshan reservoir,which have adversely affected the reservoir management and water supply safety.Therefore,it is of great significance to investigate the water quality and spatial and temporal distribution of algae communities in Qingshan reservoir and explore the influencing factors.Review historical data,track the water quality of Qingshan Reservoir from April 201 8 to March 2019,and the distribution of algae in water.Analyze water quality trends,pollution status,eutrophication and chlorophyll a and algae,environment.The correlation of the factors leads to the following conclusions:(1)Water temperature,permanganate index,ammonia nitrogen,total iron,ferric ion,pH value,dissolved oxygen,total nitrogen,nitrate nitrogen,nitrite nitrogen,total phosphorus,phosphate in the water quality index of Qingshan Reservoir Manganese showed seasonally significant differences;the transparency,ammonia nitrogen,total phosphorus,total iron,ferrous ion,ferric ion,manganese,chlorophyll a,and permanganate index in the water quality index of Qingshan Reservoir were regionally significant.The results of monitoring the microcystin LR type were not detected.(2)The main factors causing water pollution in Qingshanhu Reservoir are total nitrogen and total phosphorus,and the secondary factors are permanganate index and pH value.The nutritional status of the reservoir is basically mild and eutrophic,and the degree of eutrophication is spring>summer>autumn>winter.(3)The main algae in the reservoir are silicin,cyanobacteria and green algae.In summer and autumn,cyanobacteria and green algae are dominant,while in winter and spring,silicinella is the main.The cryptophyta and green algae in the reservoir are mainly distributed on the surface of the water body to a depth of 3 meters,and the distribution is relatively uniform;the cyanobacteria are mainly distributed in the water depth of 2-3 meters,and peaks in the water depth of 2.5 meters;the dinoflagellates are mainly distributed in the water body.The surface is between 4 meters deep and has a peak near 2 meters.(4)The content of chlorophyll a was significantly positively correlated with green algae,cyanobacteria and silicin(P<0.01).There was a significant positive correlation between chlorophyll a content and water temperature and permanganate index(P<0.01),and a significant positive correlation with pH(P<0.05).with ammonia nitrogen,nitrate nitrogen,total iron,ferric ion,Manganese showed a significant negative correlation(P<0.05).A multivariate linear regression equation with permanganate index(X1).nitrate nitrogen(X2)and water temperature(X3),as independent variables was obtained by stepwise regression analysis:y=46.773X 1+16.221X2-1.277X3-121.259,the equation The fitting degree is good(R=0.989,P<0.01),which can predict the change trend of chlorophyll a in Qingshan Reservoir and provide reference for the warning of eutrophication.