Studying the coupled effects of environmental factors on the structure of phytoplankton communities can deepen our understanding of the stability of aquatic ecosystems in extreme environments. This study examined the phytoplankton community structure and environmental factors of saline a lake during spring, summer, and autumn in 2019. A total of 95 phytoplankton species (belonging to 47 genera and 7 phyla) were identified in Ebinur Lake, reflecting a species richness lower than those of freshwater lakes while being greater than the levels observed in other saltwater lakes. Bacillariophyta dominated the phytoplankton assemblage, followed by Chlorophyta and Cyanophyta, with lesser diversity in other algal species, suggesting that the species composition was similar to that observed in other saltwater lakes. There was considerable spatiotemporal variation in the structure of the phytoplankton community, with the biomass of phytoplankton displaying notable seasonal variation. In spring, the biomass of Bacillariophyta was dominant; in summer, as the climate warmed, the biomass of phytoplankton reached its peak and the biomass of Chlorophyta was dominant; in autumn, the biomass was the lowest, and Chlorophyta and Bacillariophyta shared dominance. The spatial distribution was relatively consistent, as reflected in the distribution of phytoplankton in the three seasons, with the southeastern area of the lake generally exhibiting higher biomass than other lake areas. Bacillariophyta and Chlorophyta were significantly correlated with water transparency (SD); Cyanophyta was significantly correlated with water temperature (WT), and Cryptophyta was significantly correlated with pH. The interaction effects of various environmental factors, including pH, SD, Chl. a, NH₄+-N, and salinity, jointly affect the dynamics of the phytoplankton community structure in Ebinur Lake. This study investigated the effects of physicochemical factors on the structure of the phytoplankton community in a high-salinity lake, thereby providing a basis for ecological protection and environmental management of aquatic ecosystems in extreme environments.

The characteristics of macroinvertebrate community structure can effectively reflect the health status of lake ecosystem and the quality of the lake ecological environment. It is of great significance to identify the limiting factors of macroinvertebrate community structure for the maintenance of lake ecosystem health. In this study, the community composition of macroinvertebrate assemblages and their relationships with environmental variables in 13 small lakes within Linhuan Lake was investigated. Self-organizing map, K-means clustering analysis, principal component analysis, pearson correlation analysis, and redundancy analysis were used to analyze the correlation and variability between macroinvertebrates community index and environmental factors. The results showed that the environmental variables (pH, total phosphorus, nitrate, water temperature, dissolved oxygen, conductivity, chemical oxygen demand, and ammonium) had a significant effect on the classification of macroinvertebrate community. Molluscs were significantly negatively correlated with pH and chlorophyll a, while annelids and aquatic insects were significantly positively correlated with chlorophyll a and dissolved oxygen. Species richness and Shannon’s diversity of macroinvertebrates were significantly negatively correlated with total phosphorus while biomass of macroinvertebrates was significantly negatively correlated with pH. High alkalinity characteristics and eutrophication of the lake have a serious impact on the macroinvertebrate community. Human interference and unreasonable industrial and surface runoff from agricultural farms destroy the ecological environment and affect the community structure of macroinvertebrate. Thus, the improvement of the macroinvertebrate’s community structure should be carried out by improving the Lianhuan Lake watershed ecological environment and controlling watershed environmental pollution.