Soil Microbial Community Structures and Formation Mechanisms in Different Functional Zones of a Manganese Mine Area

The development of manganese (Mn) ore mining and electrolytic manganese industry in “Manganese Triangle” from China has led to serious Mn pollution in water and soil, posing unpredictable threats to human health and the ecosystem. However, current studies on the changes in soil microbial communities in Mn mining areas are relatively limited. Here, the status of Mn pollution in an electrolytic Mn enterprise in “Manganese Triangle” and its surrounding areas, as well as the structural characteristics of soil microbes in different regions, were investigated to reveal the driving mechanisms of environmental factors on microbial community structure. The Mn level far exceeded the background value of this region, posing potential environmental risks. Acidobacteria and Proteobacteria were the dominant microbial groups. The abundance of the microbial community in the reservoir was lower than that in other areas, whereas the diversity of the sewage treatment plant was relatively higher. Canonical correspondence and Spearman correlation analyses showed that Mn, nitrate nitrogen, ammonium nitrogen, pH, and moisture significantly affected the microbial community structure, with Mn content being the key factor. Furthermore, abundant Mn resistance genes were identified in the soil metagenomes, endowing microorganisms to tolerate high concentrations of Mn. This might be the potential mechanism affecting the changes in microbial community structure. This study clarified the structural characteristics and formation mechanisms of microbial communities in manganese mining areas, providing a theoretical basis for risk management and bioremediation of soil.