Study On The Characteristics Of Plankton Community And Its Correlation With Environmental Factors In The Middle Of The Songhua River River From Jilin To Songyuan

Songhua River River is the largest river in Jilin Province,which has very important economic and ecological value.In recent years,the ecological environment of the middle reaches of Songhua River River has changed significantly under the influence of human production,life and hydraulic engineering construction.In order to understand the characteristics of plankton community structure and its correlation with environmental factors in the jilin-Songyuan section of the middle reaches of Songhua River,the species composition and community structure of plankton in the jilin-Songyuan section of the middle reaches of the Songhua River River were studied in the summer and autumn of 2020 by conducting a two-season comprehensive survey at seven sampling sites in the jilin-Songyuan section of the middle reaches of the Songhua River River,at the same time,the abundance,biomass,diversity index,evenness index and richness index of Zooplankton were analyzed,and the redundancy(RDA)analysis between plankton community structure and environmental factors was carried out,it provides scientific basis for rational protection and utilization of water resources and ecological protection in Songhua River.The main results are as follows:7 Phyla and 103 Genera of phytoplankton were found in jilin-Songyuan section of the middle reaches of Songhua River.Among them,there are 43 species of CHLOROPHYTA,30 species of Diatom,13 species of CYANOPHYTA,3 species of dinoflagellates and 3 species of Chrysophyta,4 species of cryptoalgae and 7 species of GYMNOPHYTA.The summer phytoplankton abundance in the jilin-Songyuan section of Songhua River ranges from 297.05 to 1425.76 to 104 ind./L,the mean abundance is 676.98104 Ind./L.The total abundance of Phytoplankton in autumn ranged from 438.78 to 698.37104 Ind./L,the average abundance is 468.84104 Ind./L.The total biomass of phytoplankton was 4.6089?25.5128 mg/L,and the average biomass was 10.1537 mg/L,respectively.The total biomass of phytoplankton in autumn ranged from 4.7382 to 14.9949 mg/L,and the average biomass was 10.7331 mg/l.Phytoplankton Diversity Index(H')was 2.137 in summer and 2.291 in autumn,evenness index(J')was 0.419 in summer and 0.481 in autumn,Simpson Index(D)was 2.123 in summer and 2.361 in autumn.Based on RDA redundancy analysis,dissolved oxygen(do),transparency,pH,total nitrogen(TN),total phosphorus(TP)and water temperature were identified as the main driving factors for phytoplankton community structure and biodiversity in the Middle Songhua River.A total of 46 Genera and 4 species of zooplankton were found in the jilin-Songyuan section of the middle reaches of Songhua River.There are 26 species of Rotifer,10 species of Protozoan,6species of Cladocera and 4 species of Copepoda.The Summer Zooplankton abundance in the jilin-Songyuan section of Songhua River ranged from 17.56 to 26.68 ind./L,with an average abundance of 22.96 ind./L.The total abundance of Zooplankton in autumn ranged from 11.28 to19.76 ind./L,with an average of 14.64 ind./L.The total biomass of Zooplankton was from 0.1440 to 0.2672 mg/L,and the average biomass was 0.1901 mg/L.The total biomass of Zooplankton in autumn ranged from 0.2479 to 0.3452 mg/L,and the average biomass was 0.3107 mg L.The diversity index(H')of zooplankton was 2.469 in summer and 2.521 in autumn,the evenness index(J')was 0.486 in summer and 0.474 in autumn,and the Simpson Index(d)was 2.523 in summer and 2.559 in autumn.According to RDA redundancy analysis,dissolved oxygen saturation(COD),electrical conductivity(Sp Cond.),transparency(TRA.),pH and salinity(Sal.)Were identified as the main driving factors affecting zooplankton community structure and biodiversity in the Middle Songhua River.In this study,the water quality and the status of plankton in the study area were identified,and the environmental factors and plankton diversity index were used to evaluate the water quality and health status of the rivers in the study area.The results provide basic data support for the future protection of aquatic biological resources and environmental management in the jilin-Songyuan section of Songhua River.