Effect of coal mining subsidence on soil microbial communities in mining areas with high groundwater levels

In high groundwater level mining areas, coal mining has led to severe surface subsidence, which not only alters soil physicochemical properties but also destabilizes microbial communities, ultimately impairing ecosystem functions. This study explores the impact of mining-induced subsidence on soil microbial communities in regions with high groundwater and aims to uncover the mechanisms driving these shifts. We collected surface, middle, and deep soil samples from the subsidence areas of both the deep (T1) and shallow (T2) coal seams of the No. 3 Coal Mine in Jining, Shandong province, along with their respective control areas (W1 and W2). The physicochemical properties and microbial community composition of these samples were analyzed. The results indicated that coal mining subsidence significantly alters soil properties and reshaped microbial community structures. Compared to non-subsidence areas, soil nutrient content in subsidence areas decreased by 7.96-43.95%, while soil pH (pH) decreased by 6.33%. In contrast, soil water content (SWC) and bulk density (BD) increased by approximately 12.63 and 6.04%, respectively. Concurrently, microbial community richness and diversity declined by 16.41 and 6.65%, respectively. Despite this decline, the relative abundance of certain microbial taxa, including Actinobacteria, Chloroflexi, and Myxococcota, was higher in subsidence areas. Structural equation modeling further revealed that coal mining subsidence, in conjunction with soil physicochemical properties, accounted for 51-72% of the observed variation in microbial communities. Among the measured factors, soil available potassium (AK) had a significant direct influence on microbial communities, whereas SWC emerged as the most influential indirect factor. These findings provide critical insights into the ecological consequences of coal mining subsidence in high groundwater level areas and offer valuable guidance for land reclamation and soil ecological restoration efforts.