Community Structure Of Macrobenthos And Biological Evaluation Of Water Quality In Lianhuan Lake

In recent years,human demand for water resources has continued to increase,and the overexploitation of water resources and water ecological environmental pollution have become increasingly prominent,posing potential threats to the structure and function of the lake ecosystem.The gradual deterioration of the health of lake ecosystems is the main problem faced by lakes in northern China represented by Lianhuan Lake.As a key group of lake ecosystems,macrobenthos are a key indicator of lake health.Based on the dynamic changes of macrobenthos and environmental factors,this research conducted an ecological survey on the14 main lakes connected to each other in Lianhuan Lake,analyzed the temporal and spatial distribution of the existing stock of Benthos in the Lianhuan Lake,the temporal and spatial distribution of biodiversity,the community structure of benthos and the indicator species of each community,and based on the physical and chemical indicators and biological indexes,the physicochemical evaluation and biology of the shells of Lianhuan Lake were evaluated.and the relationship between benthic community structure,benthic species composition and benthic biological index and environmental factors were explored.To understand the ecosystem of Lianhuan Lake,provide scientific argumentation and data support for the protection of Lianhuan Lake's ecosystem.The main results are as follows:1.From June to October 2020,75 species of macrobenthos were collected from Lianhuan Lake,belonging to 15 orders and 32 families.The temporal and spatial distribution of benthic species number is quite different.Among them,Habuta lake has the largest number of species,with 19 species,Xihulu lake has the least number of species,with 5 species,and the temporal change rule of species number is summer>spring>autumn.The spatiotemporal distribution of abundance and biomass has a higher coincidence rate,with Habuta lake being the highest.Margalef Richness Index,Pielou Evenness Index,Shannon-Wiever Diversity Index and Simpson Diversity Index are quite different among lakes,but the changes are small in terms of seasonal span.Based on Self-organizing feature map and K-means cluster analysis,the benthic community structure is divided into 5 groups,Among them,groups ? and ? reflect the temporal characteristics of the benthic community structure,while groups ?,? and ? reflect the spatial heterogeneity of the benthic community structure.The indicator species of the 5 groups accurately reflect the seasonal changes in various regions and the interference of human activities.2.The results of biological evaluation of water quality based on the benthic biological index are basically the same as the results of physical and chemical evaluation of water quality based on the physical and chemical indicators of water bodies.The Margalef index and Shannon-Wiever index show that the water quality of Lianhuan Lake is moderately polluted in spring,summer and autumn.The Simpson index shows that the water quality of Lianhuan Lake has shifted from light pollution to medium pollution over time,while the BI index shows that the water quality of Lianhuan Lake has been in light pollution.The physical and chemical evaluation of water quality showed that the permanganate index,total phosphorus,total nitrogen and ammonia nitrogen were the main pollution indicators.The comprehensive evaluation showed that the water body of Lianhuan Lake was between Grade III and Grade IV water quality in spring,summer and autumn.3.Macrobenthos are significantly affected by environmental factors.Natural factors and human activities are the main driving forces affecting the distribution of benthic communities.Water temperature,dissolved oxygen,ammonia nitrogen,chlorophyll a and permanganate index have significant effects on the classification of benthic communities.The species composition of macrobenthos is significantly affected by water temperature,dissolved oxygen,p H,nitrite nitrogen and permanganate index.Dissolved oxygen,p H,conductivity,permanganate index,total phosphorus,total nitrogen,nitrate nitrogen and nitrite nitrogen are significantly or extremely significantly correlated with benthic biological indexes.