Linking Microbial Community Structure to Trait Distributions and Functions Using Salinity as an Environmental Filter.

Area of Science:

• Microbial ecology
• Environmental microbiology
• Soil science

Background:

• Microbial community structure and function are influenced by environmental gradients.
• Linking microbial traits to community structure and ecosystem functions remains a challenge.
• Soil microbes are crucial for ecosystem processes like nutrient cycling.

Purpose of the Study:

• To investigate how salinity shapes soil microbial community trait distributions, structure, and function.
• To interlink microbial salt tolerance traits with community composition and resulting ecosystem functions.
• To apply a trait-based approach to understand microbial community influence on ecosystem processes.

Main Methods:

• Applied salinity as an environmental filter to nonsaline soil (0-22 mg NaCl g⁻¹).
• Determined salt tolerance traits using bacterial growth dose-response relationships.
• Analyzed bacterial community structure via 16S rRNA gene amplicon sequencing.
• Measured microbial functions including respiration, bacterial growth, and fungal growth.

Main Results:

• Salt exposure filtered microbial trait distributions, with stronger filters causing larger shifts.
• Filtered trait distributions correlated with community composition, indicating species turnover.
• Salt decreased respiration but induced competitive interactions in microbial growth.
• Fungal growth peaked at high salinity, suggesting higher fungal salt tolerance than bacterial tolerance.

Conclusions:

• Salinity effectively filters microbial communities, linking trait distribution to community structure and function.
• The study demonstrates a framework for attributing ecosystem functions to microbial communities based on traits.
• Findings highlight the differential salt tolerance of fungal and bacterial communities in nonsaline soils.