Salinity controls soil microbial community structure and function in coastal estuarine wetlands

Area of Science:

• Environmental microbiology
• Coastal ecology
• Biogeochemistry

Background:

• Soil salinity is a major environmental factor influencing microbial communities.
• Its impact on microbial diversity and biogeochemical processes in estuarine wetlands remains unclear.

Purpose of the Study:

• To investigate the effects of salinity gradients on bacterial community composition and functional genes in a coastal estuarine wetland.
• To understand how salinity influences microbial diversity and biogeochemical processes.

Main Methods:

• Utilized 16S rRNA gene sequencing to characterize bacterial communities.
• Employed microarray-based GeoChip 5.0 to analyze microbial functional genes.
• Examined soils across a salinity gradient from oligohaline to hypersaline habitats.

Main Results:

• Higher bacterial richness and phylogenetic diversity were observed in saline soils compared to freshwater-affected habitats.
• Salinity-driven shifts in bacterial taxa, with Gammaproteobacteria, Bacteroidetes, and Firmicutes increasing with salinity.
• Abundance of carbon and nitrogen cycling genes decreased with salinity, except for the hzo gene, indicating anammox process importance.

Conclusions:

• Salinity acts as a strong deterministic filter shaping bacterial community assembly in estuarine wetlands.
• Soil salinity significantly inhibits crucial soil biogeochemical processes, impacting ecosystem functions.