Taxonomic variability and functional stability across Oregon coastal subsurface microbiomes

Area of Science:

• Marine microbiology
• Geomicrobiology
• Community ecology

Background:

• Factors shaping marine subsurface sediment microbial communities are poorly understood.
• Subsurface sediments represent a vast, under-explored microbial habitat.

Purpose of the Study:

• To investigate the drivers of microbial community structure in marine subsurface sediments.
• To differentiate between functional and taxonomic community responses to environmental factors.

Main Methods:

• Metagenomics for functional gene structure analysis.
• 16S rRNA gene amplicon sequencing for taxonomic composition.
• Physicochemical measurements and statistical modeling (Mantel tests, regression, permutation null models).

Main Results:

• Functional community structure was stable across a wide geographic area (>300 km).
• Taxonomic composition varied significantly at the amplicon sequence variant (ASV) and operational taxonomic unit (OTU) levels.
• Geographic distance and physicochemical variables poorly explained taxonomic variability.
• Community assembly analysis indicated strong taxa segregation (exclusion).

Conclusions:

• Biological interactions, rather than environmental factors, are key drivers of taxonomic variation in marine subsurface sediments.
• Taxonomic variation can be decoupled from functional community structure.