Community Structure Changes And Driving Factors Of Planktonic Eukaryotes In Inter-Basin Water Transfer Canal(China)

Planktonic eukaryotes are an important part of aquatic ecosystem,and it is of great significance to analyze the community composition and function of planktonic eukaryotes for water resource management.In order to understand the spatial and temporal distribution and driving factors of plankton eukaryotes in the central canal of the South-to-North Water Transfer Project,we investigated the phytoplankton eukaryotes and physical and chemical indexes at five stations along the canal and one station in front of Qushou Dam from March to December 2019.The spatial and temporal variation and driving factors of plankton eukaryotes community structure in the canal of the South-to-North Water Transfer project were analyzed,and the community succession and distribution pattern of plankton eukaryotes in the canal of the South-to-North Water Transfer project were discussed.The results of high-throughput sequencing showed that the phytoplankton eukaryotes in this area were mainly composed of 53 phyla,96 classes,129 orders,158 families,200genera and 277 species,and Cryptomonadales was the dominant species in the south section of the main canal.The eukaryotic community composition had obvious seasonal variation,and the spatial factors had certain influence on the eukaryotic community composition of the canal in Henan province.In the process of water transport,the planktonic eukaryotes are not only transported passively,but also proliferated,grew or died.The eukaryotic community structure of Taocha(TC)was more significantly affected by water supply from Danjiangkou Reservoir,while the relative abundance and species number of eukaryotes decreased with the increase of water transport distance.Through redundancy analysis(RDA)of eukaryotic plankton community and environmental factors,it was found that REDOX potential(ORP),nitrate nitrogen(NO₃^--N),p H,total phosphorus(TP)and flow velocity(Vel)were the main factors affecting eukaryotic plankton distribution.Distance-decay analysis showed that the geographical distribution of eukaryotic communities followed the distance-decay model,that is,community similarity decreased with the increase of geographical distance and environmental heterogeneity.VPA analysis showed that environmental factors had an absolute advantage in explaining eukaryotic communities compared with spatial and seasonal factors,and environmental selection was the dominant factor in the geographical distribution of eukaryotic communities.The results of this study complement the lack of understanding of the diversity and ecological distribution of planktonic eukaryotes in inter-basin water transfer channels,and contribute to understanding the ecological response of planktonic eukaryotes in inter-basin water transfer projects.