Study on the structure of microbial communities in water bodies

The assembly mechanisms of microbial communities have a significant impact on ecosystem function and stability. However, the relative roles of deterministic processes (such as environmental filtering) and stochastic processes (such as diffusion and migration) in different habitat types are not fully understood. Based on the typical river-lake interface zone in the middle and lower reaches of the Yangtze River, this study systematically analyzed the spatial distribution and assembly patterns of microbial communities in the water column, sediment, and coastal soil using 16S rRNA high-throughput sequencing and qPCR techniques. The results showed that environmental filtering factors (such as pH and dissolved oxygen) played a dominant role in the structure and functional diversity of microbial communities in sediment and coastal soil, while the microbial communities in the water column were more driven by stochastic processes, reflecting the significance of diffusion effects in flowing water bodies. By introducing "community integration" into the study of ecological patterns for the first time, we revealed how microbial interactions between habitats shape community heterogeneity and ecosystem stability. Especially during the wet season, the diffusion effect of water bodies promotes the integration of microorganisms between the water column and sediment, enhancing species sharing and functional redundancy, thereby improving the stability and resilience of ecosystems. This study provides a new perspective for the theory of microbial community assembly, emphasizes the important role of community integration in the formation of habitat ecological patterns, and offers important insights for habitat management and ecological restoration.