Responses of microbial community to different depths in volcanic soils of Nvshan Volcano.

The depth of the soil has a vital impact on determining the composition and structure of the soil microbial community. However, research exploring microbial community profiles at various soil depths within volcanic ecosystems remain scarce. Soil samples were gathered and examined from volcanic regions to assess and microbial properties. The findings indicated that the diversity and richness of bacteria declined as the depth increased. The absolute abundance of bacteria (16 S rRNA gene copies) showed remarkable dissimilarities among surface, middle, and deep soil (P < 0.05). The co-occurrence revealed that the networks of bacteria in deep soil displayed a larger quantity of nodes and edges, suggesting higher complexity in contrast to those in surface and middle soil (Nodes: 1745 versus 1547 and 1460; Edges: 166,891 as opposed to 125,384 and 96,150). As soil depth increased, stochastic processes’ impact on the assembly of bacterial community grew progressively stronger (R² values: 0.365, 0.428, 0.537). Correlation analyses revealed that soil environmental factors significantly influence the microbial community’s average variation and niche breadth. These results offer insights into how volcanic environments at different depths impact microbial communities.