Macrobenthos Research And Water Quality Evaluation Of Guanting Reservoir And Inflowing Rivers

Since the release of major national“13th Five-Year Plan”projects,more and more attention has been paid to the construction of large-scale green ecological protection spaces,green corridors connecting various ecological spaces,the construction of large reservoirs,and the completion of important river treatment projects in various parts of China.And practice the concept of"green water,green mountain is the golden mountain and silver mountain",the local hydrological environmental protection bureaus have carried out real-time monitoring of the river ecology.Therefore,we conducted a preliminary study on the water quality and biodiversity of the Guanting Reservoir and its main rivers—Sanggan River,Yanghe River,and Qingshui River.In order to clarify the biodiversity and water pollution of the Guanting Reservoir and its incoming rivers,we set up a total of 17 sampling points based on the hydrological and geographical conditions of the reservoirs and rivers,from April 2019to October 2019.In spring,summer,and autumn,quantitatively collect large-scale benthic animals and water samples at 17 sampling points of the Guanting Reservoir and its incoming rivers,and use the instrument to measure the temperature,flow rate,and pH of the river at the site.The large-scale benthic animal samples collected in the laboratory were classified and screened,and the physical and chemical indexes of TN,TP,COD_Mn,NH₃-N,NO₃-N,and NO₂-N of the water samples at 17 sampling points were measured by instruments.Based on the results of the measurements,we will make ecological assessments of the biodiversity and water pollution indicators of the Guanting Reservoir and its incoming rivers,and analyze and explore the correlation between large-scale benthic animals and environmental physical and chemical factors in the water.1.This survey found a total of 3 species,5 classes,10 families,19 genera,and a total of 1078 large-scale benthic animals,of which the largest mollusk catch was 837,accounting for 78%of the total number,followed by aquatic oligochaos.There are185,accounting for 17%of the total number,and the catch of aquatic insects is at least 56,accounting for only 5%of the total.The dominant species are flat snails,turnip snails,and waterworms.And the average density of the collected macrobenthos is 259.0ind/m²,and the average annual biomass is 37.2g/m².The density of aquatic insects,mollusks and aquatic oligochaetes is the highest in autumn,and the density of aquatic oligochaos is in summer.At the lowest time,or related to fish predation in the water body;except for mollusks,the seasonal changes of aquatic insects and aquatic oligochaetes biomass have the same trend as the changes in density,and the maximum season of mollusc biomass occurs in summer.In summer,snails are bulky and heavy,which leads to summer biomass;changes in the density and biomass of aquatic insects are related to the emergence of some chigger larvae in the summer.From the perspective of the density,biomass,and seasonal changes of macrobenthos at each sampling point,the biomass distribution at each sampling point is uneven,and the species are also greatly different.On the whole,the biological richness of Guanting Reservoir and the incoming river Higher,the biodiversity of macrobenthos in each watershed is smaller.2.Collect the water samples,and measure the physical and chemical indicators of total nitrogen,total phosphorus,nitrate nitrogen,and nitrite nitrogen in the laboratory.According to China's drinking water evaluation standards,the physical and chemical indicators are classified separately and obtained The water quality results of the sampling points were generally in Class III and IV water quality.Based on the results of various physical and chemical indicators,the water pollution of Qingshui River,Yanghe River,Sanggan River,and Guanting Reservoir were analyzed respectively.The water quality is V,and the water quality of Guanting Reservoir is III.The water quality is good.We use the principal component analysis method and computer operation to analyze the main pollution components of various physical and chemical factors.The main chemical pollution factors of rivers are nitrogen and phosphorus.3.Use Shannon-Weaver diversity index?H'?,Margalef species abundance index?d_M?,Pielou uniformity index?J?,biological pollution index?BPI?,and pollution resistance index?BI?according to each sample.The results of the species and quantity of large-scale benthic animals at each site were evaluated for the degree of water pollution at each sampling point.The results showed that,except for point 1 where the pollution was severe,the water pollution degree at other locations was on average light and medium,and the water quality was good;Coefficient formula to analyze the correlation and connection between the species,density,and biomass of large benthic animals and various chemical environmental factors.The results show that the number,density,and biomass indicators of large benthic animals are related to TP,TN,and NH₂-N.The correlation between isophysical and chemical indicators is not obvious;NO₃-N has a significant positive correlation with the density and biomass of aquatic oligochaetes,indicating that eutrophic waters polluted by nitrogen sources are beneficial to the growth of aquatic oligochaos.The oligochaetes can indicate the degree of water pollution;and the number of macrobenthos species is not significantly related to the rest of the water physical and chemical indicators.