Microbial Community Composition and Major Environmental Factors Influencing Changes in Different Vegetation Soils of...

The soil microbial community in coastal wetlands plays a crucial role in biogeochemical cycling. In this study, Spartina alterniflora soil (HB), found near the sea; Spartina alterniflora soil (ZY), found near land; and Phragmites australis soil (KA), found in coastal wetlands, were selected to study the microbial community structure and major environmental influencing factors. The results showed that environmental factors had a significant difference in the three soils. Compared with the ZY and KA sites, the soil at the HB site had the highest value of salinity (14.1 g/kg) and the lowest value of total organic carbon (TOC) (2.9 g/kg) in summer. At the KA site, the values of soil temperature, soil humidity (SH), TOC, and NH₄⁺ were higher than those at HB and ZY sites, while the values of EC (159.8 μS/cm in summer) and salinity (4.4 g/kg) were the lowest. Furthermore, the microbial community structure had significant differences at the three sites. Pseudomonas and Bacteroidota dominated at the HB site, while Chloroflexota and Gemmatimonades were more abundant at the ZY and KA sites. Microbial alpha diversity analysis indicated that the microbial community diversity of Phragmites australis soil was the most uniform, and the microbial species richness in the soil of Spartina alterniflora near the sea was the highest. Salinity, TOC, and SH might be the key environmental factors that affect the structure and diversity of microbial communities in soils. High-salt environments may promote the enrichment of salt-tolerant microbial communities, while high TOC and suitable soil humidity may enhance the uniformity of microbial communities.