Research On The Relationship Between Plankton Community Structure And Environmental Factors In The Burhatong River Basin

Aquatic ecosystem is an important natural resource for the sustainable development of human beings.River ecosystem connectivity is the link of aquatic ecosystems and plays a key role in material cycle and energy flow channels.With the rapidly urbanization,a large amount of pollutants flow in,exceeding the assimilation capacity of the river ecosystem,leading to loss of biodiversity,and threatening the quality and stability of aquatic ecosystems.The structure of biological communities in ecosystems and the relationship between biodiversity and water environmental factors are crucial for elucidating the dynamics and processes driving diversity in riverine ecosystems.Most current studies on the relationship between plankton and environmental factors mainly examine the taxonomic level of plankton.However,we still know little about the correlation between the functional level of plankton and environmental factors.The Burhatong River Basin is a secondary tributary of the Tumen River.The Burhatong River Basin flows through areas where cities are concentrated and the population is densely distributed.It is the most polluted river among the various tributaries of the Tumen River.Therefore,it is urgent to manage water pollution,protect biodiversity,improve the ecological environment,and ensure the sustainable use of water resources in this area.The Burhatong River Basin,a tributary of the Tumen River in Jilin Province,was taken as the research area in this study.In July 2022,a total of 105 stations of the two rivers,Burhatong River and Hailan River,to which it belonged,were investigated for water ecology research.Plankton were chosen as a model in this study.Based on the plankton community structure,taxonomic diversity and functional diversity,and community productivity,the correlation between them and water environmental factors is explored,aiming to provide a basis for the ecological protection,governance,and sustainable development of the Burhatong River Basin.Provide a theoretical basis for sustainable development.The main results and conclusions of this paper are as follows:(1)A total of 213 species of phytoplankton were observed in the Burhatong River Basin,belonging to seven phyla.Among them,there are 145 species of diatoms,accounting for 68.08%,the largest number of species,38 species of Chlorophyta,accounting for 17.84%,followed by 15 species of Cyanophyta,accounting for 7.04%,and 15 species of other phyla.Among them,the main dominant species in the Burhatong River Basin are Phormidium tenue、Cyclotella sp.、Synedra acus、Synedra ulna、Achnanthes lanceolata,there are significant differences in the phytoplankton community structure of the two water systems,but the difference is small.There is no significant difference in species richness,density,and biomass,and there is no significant difference in taxonomic diversity.Among them,the functional richness of the Burhatong River was significantly higher than that of the Hailan River,and the functional differentiation index of the Hailan River was significantly higher than that of the Burhatong River.This shows that the ecological niche competition of phytoplankton in Hailan River is relatively high,and the degree of functional homogeneity is higher than that in Burhatong River.(2)A total of 77 species of zooplankton were observed in the Burhatong River Basin,belonging to four groups.Among them,there are 42 species of rotifers,accounting for 54.55% of the species,followed by 23 species of protozoa,accounting for 17.84%.There are 7 species of Cladocera,accounting for 9.09%,and 5 species of Copepoda,accounting for 6.49%.Among them,the main dominant species in the whole Basin of Buerhatong River and Buerhatong River is Difflugia globulosa,and the main dominant species in Hailan River are Difflugia globulosa、Centropyxis discoides.There are significant differences in the zooplankton community structure of the two water systems,but the difference is small.There is no significant difference in species richness,density,and biomass,and there is no significant difference in taxonomic diversity.Among the functional diversity,the functional richness of the Burhatong River was significantly higher than the Hailan River,and the functional differentiation index of the Hailan River was significantly higher than that of the Burhatong River.This shows that the ecological niche competition of zooplankton in the Hailan River is relatively high,and the degree of functional homogeneity is higher than that in the Buerhatong River.(3)In this study,the main environmental factor affecting the phytoplankton community structure in the Burhatong River Basin and the two water systems is water temperature(Temp).p H and chlorophyll-a(chl-a)were highly significantly positively correlated with the functional dispersion index(FDis)of phytoplankton.The main environmental factors affecting the zooplankton community structure in the whole watershed of the Burhatong River are water temperature(Temp),electrical conductivity(Cond),phosphate(PI),and total phosphorus(TP).Among them,water temperature(Temp),phosphate(PI),and total phosphorus(TP)are the main environmental factors affecting the change of zooplankton community in Buerhatong River.Conductivity(Cond)and total phosphorus(TP)are the main environmental factors affecting the change of zooplankton community in Hailan River.Permanganate index(COD)was significantly positively correlated with functional richness.There was a significant positive correlation between nitrate nitrogen(CAS),total nitrogen(TN)and functional dispersion index(FDis).(4)Community productivity and corrected community productivity increased with zooplankton species richness in the Burhatun River Basin.The productivity of phytoplankton and the productivity of zooplankton are both significantly correlated with depth(Depth),the productivity of phytoplankton is significantly positively correlated with dissolved oxygen,the productivity of phytoplankton is significantly positively correlated with the content of total nitrogen in the Burhatong River Basin,and the correction of phytoplankton and animals resource use efficiency(RUE)positively correlated with total nitrogen(TN)and total phosphorus(TP).In summary,the phytoplankton in the Burhatong River Basin are dominated by diatoms,and the zooplankton are dominated by protozoa and rotifers.The level of plankton diversity is low,the taxonomic beta diversity value is high,but the functional beta diversity is low,tending to functional homogeneity.Phytoplankton productivity and zooplankton productivity are greatly affected by the top-down movement of plankton.The overall level of the water environment in this basin is relatively good,but the content of nitrogen and phosphorus in some points is relatively high.This study assesses the role of plankton community structure in water quality and its response to environmental factors.The research results fill in the gaps in the survey of plankton communities in the flood season in the Burhatong River Basin,and provide a theoretical basis for scientific prediction and ecological restoration of river resources.