Effects of soil types on microbial networks and biogeochemical cycles in Yalu river wetland

Wetland soil microorganisms play a crucial role in wetland ecosystems. In different wetland soil types, microbial communities, networks and functional genes change. However, there are few studies on the changes in these indicators and their influencing factors across different wetland soil types. Taking the Yalu River estuary wetland as an example, Macrogenome sequencing technology, in conjunction with redundancy analysis (RDA) and partial least squares path modeling (PLS-PM), was employed to investigate the microbial community composition, network structure, and the pathways of carbon (C), nitrogen (N), and sulfur (S) cycling, as well as their correlations with environmental factors across five predominant soil types in the Yalu River Estuary wetland: salt soil (SS), swamp soil (BS), paddy soil (PS), meadow soil (MS), and brown forest soil (BFS). The findings indicated significant differences in the relative abundance of major archaea across various wetland soil types (P < 0.05). Additionally, the bacterial diversity, as measured by the Shannon index, exhibited significant variation (P < 0.05). Both the Chao1 and Shannon indices for archaea exhibited significant differences (P < 0.05). The bacterial co-occurence network in BS exhibits greater stability, whereas the archaeal co-occurence network in PS demonstrates increased complexity. Analysis of the carbon, nitrogen, and sulfur cycle pathways, as derived from the DiTing database, revealed distinct variations in soil types and gene abundances associated with each functional cycle pathway. The Sankey diagram results indicated that the microorganisms participating in the carbon (C), nitrogen (N), and sulfur (S) cycles were predominantly Proteobacteria, Euryarchaeota, Thaumarchaeota, Actinobacteria, and Bacteroidetes. Redundancy analysis revealed that soil organic carbon (SOC) and total phosphorus (TP) were the most influential factors for bacteria and archaea, respectively, with TP being the primary determinant for the C, N, and S cycles. Partial least squares path modeling (PLS-PM) demonstrated that soil factors exerted the most significant influence on archaeal diversity and the C, N, and S cycles, while their impact on the co-occurrence network of bacteria and archaea was relatively weak.