Soil bacterial community functions and distribution after mining disturbance

Abstract Mining disturbances alter soil edaphic factors, modifying soil biogeochemical processes and thus impacting the soil microbiome. The objectives of this study were (1) to identify the dominant edaphic factor influencing the soil bacterial functions after mining disturbance and (2) to investigate how the soil microbiome was distributed, relative to the dominant edaphic factor. We found that soil pH was the most important predictor explaining the distribution of microbial attributes, such as microbial diversity, taxonomic composition, and ecological clusters along a mining disturbance gradient. Our structural equation model (SEM) indicates that soil pH shaped the bacterial community indirectly, by altering soil nutrients and metal availability. Furthermore, the microbial functions responded to soil pH, as the soil microbiome was sensitive to changes in nutrient and metal(loid) availability. For example, the bacterial community was enriched in core functional genes associated with nutrient availability (including nitrogen and phosphorus) in soil with high pH, whereas there were more core functional genes involved in metal availability (including metal transport and resistance) in soil with low pH. We conclude that soil pH is a key controller of soil bacterial communities, due to its direct and indirect effects on the availability of nutrients and metal(loid)s, after mining disturbance.