Analysis On The Relationship Between Phytoplankton Community Characteristics And Water Environmental Factors In Hulun Lake

Hulun Lake is a steppe-type lake in a typical cold and arid region in the Inner Mongolia Plateau.The eutrophication of the lake's water environment and the spatiotemporal changes of the phytoplankton community are mostly affected by regional geography,hydrological and climatic characteristics,diversity of biological communities,and human activities.In order to reveal the eutrophication of Lake Hulun Lake,the changes in phytoplankton community structure and spatial-temporal distribution and its relationship with water environmental factors,this paper takes Lake Hulun as the research area,and calculates and analyzes the lake water by sampling Lake water body eutrophication,phytoplankton species composition,abundance,biomass and distribution characteristics of dominant species.Correlation analysis,redundancy analysis,multiple linear stepwise regression analysis and principal component analysis were used to enrich lake water body.The relationship between eutrophication and phytoplankton community was studied.The main results are as follows:(1)A total of 8 phytoplankton,66 genera,and 110 species(including deformation and variants)were identified,of which Cyanophyta algae Microcystis was the most dominant,followed by diatom phytoplankton and Komannella phytoplankton,and phytoplankton The change in the proportion of species shows a characteristic that changes with time.(2)The abundance of phytoplankton is between 7.874 × 105 pcs/L—16.784 × 105 pcs/L,with an average value of 11.766 × 105 pcs/L.The composition structure of the community exhibits characteristics that change with time,and is mainly cyanobacteria-green algae-Diatom type;phytoplankton biomass is between 5.525 and 7.557 mg/L,with an average value of 6.375 mg/L.The time variation trend is consistent with abundance.(3)The average values of the Hulun Lake diversity index H,richness index D,and evenness index J are 3.406,3.362,and 0.587,respectively,and the differences in the three biological indexes at different times are not significant,indicating that the Hulun Lake is planktonic.The plant community is rich in diversity,strong stability,and good uniformity.The diversity index H and richness index D both show changes in the northwest and southeast of the lake area above the lake center.The diversity index H and richness index D are the largest at 1.5m underwater and 0.5m above the sediment,respectively.Value,and the uniformity index J does not change significantly with water depth.(4)Analysis of the factors affecting the eutrophication of the water body of Hulun Lake,the results show that total phosphorus,pH value,salinity,water depth,total nitrogen and dissolved oxygen are the main influencing factors of eutrophication of the water body,and the total phosphorus affects the lake The response probability of eutrophication was 65.7%;through correlation analysis,redundancy analysis,multivariate linear stepwise regression analysis,and principal component analysis of phytoplankton and water environmental factors,the water temperature was the most influential factor for phytoplankton abundance and biomass.Significant water environmental factors,and the effect of water environmental factors on phytoplankton abundance can be extracted from 5 main components.