High-Altitude Open-Pit Coal Mining has Changed the Sulfur Cycle and Ecological Network of Plant Rhizosphere...

Ecological restoration of mining sites has a considerable effect on microbial community dynamics; however, its impact on sulfur cycling is unclear. This study explored the changes in functional genes related to sulfur cycling and microbial diversity during different stages of succession following the ecological restoration of a mining site in a cold arid area. A total of three succession stages were selected-natural, secondary, and artificial. The expression of sulfur cycle-related genes and associated microbial drivers was investigated using metagenomics and network analysis. The dominant bacteria in the secondary succession were found to be r-strategy-adopting Proteobacteria and Cyanobacteria. Natural succession primarily comprised Aspergillus and Thermus, whereas artificial succession comprised Proteobacteria, Chlorophyta, and Actinobacteria. Mining disturbances were determined to significantly reduce the abundance of sulfur-cycling archaea. Secondary succession was primarily influenced by soil total phosphorus in the sulfur-cycle gene network. The key bacteria and archaea involved in the sulfur cycle were found to be Bradyrhizobium and Nitrosopumilus, respectively. The abundance of Streptomyces was significantly higher in natural succession than in artificial or secondary succession. Burkholderia, which has biological control and bioremediation effects, was abundant during artificial succession. These results provide a theoretical basis for restoring the sulfur cycle and promoting a positive succession of ecosystems in mining areas.