Shift in the Microbial Community Composition in Lake Wetland Sediments in the Source Region of the Yellow River Linked to Environmental Factors

The source region of the Yellow River, as the main flow-producing area, contributes more than 35% of the total flow of the Yellow River. Here, we surveyed the spatial distribution of the bacterial and fungal communities in the 17 sedimental sites of Longyangxia Valley and Donggi Conag Lake within the source region of the Yellow River. The results revealed that bacterial richness and diversity were higher at the lower elevation of Longyangxia Valley (2588 m) than at higher elevation of Donggi Conag Lake (4096 m), while no obvious differences in fungal richness and diversity were observed. The abundance of the bacterial phylum Actinobacteriota increased in Donggi Conag Lake (30.8%) compared to Longyangxia Valley (15.9%) as the elevation increased. Meanwhile, the abundance of the fungal phylum Rozellomycota decreased (17.6–3.0%) as the elevation increased. The redundancy analysis suggested that the structures of the bacterial and fungal communities were influenced by environmental factors including elevation, organic matter content, hydrolyzed nitrogen, total phosphorus, total potassium, and pH. The results highlighted that rather than the fungal community, the bacterial community in sediments exhibited more significant spatial variation in lake wetlands driving by the influence of elevation and physicochemical variables.