Salinity gradient distribution pattern and driving factors of bacterial communities in sedi-ment of lakes on the Qinghai-Tibet Plateau
Salinity is one of the most important environmental factors affecting bacterial communities in lake sediments.Revealing the impact of salinity on bacterial community changes is of great significance for a deeper understanding of bacterial communities in aquatic ecosystems.This study focused on 22 lakes in the southwest of the Qinghai-Tibet Plateau,explored the bacterial richness,evenness and community composition of 33 sediment samples,analyzed their changes with salinity,and elucidates their potential environmental driving factors.The results showed that Proteobacteria,Bacteroidetes and Actinobacteria were the dominant bacterial phyla in the sediment of lakes,with relative abundances of 46.54％,12.41％and 7.23％,respectively,totaling 66.18％of the en-tire bacterial phyla.For bacterial α diversity,species richness,and evenness showed a significant downward trend with increasing salinity.For bacterial β diversity,based on non-metric multidimensional permutation analysis,bacterial community distribution could be divided into three significant independent clusters by salinity,corresponding to freshwater,saline and high salinity envi-ronments,respectively.The Mantel test results indicated that compared to geographical distance,the Bray-Curtis dissimilarity of lake sediment bacterial communities varied more significantly with salinity.The results of variance decomposition analysis and ran-dom forest analysis indicated that the best predictive factors for changes in bacterial species richness,evenness and community composition were chemical factors such as salinity and phosphate,with overall contribution rates of 72.98％,59.82％and 60.83％,respectively.Among them,salinity was the main driving factor for changes in richness,evenness and community composition,with relative contribution rates of 45.47％,79.18％and 79.50％,respectively.Furthermore,relying on structural equation modeling,changes in bacterial richness,evenness and community composition in lake sediment were directly or indirectly affected by salinity.The results of this study fully explored the impact of salinity on bacterial community changes and revealed the bacterial composition and environmental driving factors of sediment in lakes on the Qinghai-Tibet Plateau.This provided scientific support for understand-ing the response of bacterial communities in lake ecosystems to environmental changes.
万方数据
维普
