Spatial Variations of Aquatic Bacterial Community Structure and Co-Occurrence Patterns in a Coal Mining Subsidence Lake

Land subsidence caused by underground coal mining critically influences the structure and function of ecosystems in mining areas. However, knowledge on the aquatic bacterial community structure and interspecies interactions in subsidence lakes are still limited. To address this issue, we collected water samples from a coal mining subsidence lake and its connected river and investigated the spatial distribution and co-occurrence patterns of the bacterial community using 16S rRNA amplicon sequencing. The results revealed that the bacterial alpha-diversity in the subsidence lake was higher than that in the river. The bacterial community composition was also significantly different between the subsidence lake and its connected river. Total nitrogen explained 21.4% of the bacterial community composition variation, while sulfate explained 38.4% of the bacterial functional composition variation. Co-occurrence network analysis indicated that the modularity indices and stability of the microbial network in the subsidence lake were significantly higher than those in rivers, which presented more resistance to environmental disturbance. Keystone bacterial taxa in the subsidence lake and river included the Clostridiaceae 1 family, and the Shewanella, Flavobacterium, and Limnohabitans genera, which play vital roles in the carbon, sulfur, and nitrogen cycles. Moreover, functional analysis showed that assimilatory sulfate reduction processes had a major role in the sulfur cycle of the subsidence lake and its connected river ecosystem. Overall, our findings provide new insights into the microbial community structure and assembly in subsidence lakes and its connected river ecosystems, with significant implications for the responsible utilization of water resources and the promotion of sustainable development in mining areas.