Spatial Resolution of Microbial Community Members Within Cyanobacterial Mats From Temperate Mud Flats

Area of Science:

• Microbial Ecology
• Environmental Microbiology
• Biogeochemistry

Background:

• Benthic cyanobacterial mats (BCMs) are globally distributed in aquatic habitats.
• Their microbial composition is influenced by environmental factors, creating complex spatial and temporal structures.
• Temperate BCMs are increasingly used as model systems for community and nutrient cycling studies.

Purpose of the Study:

• To molecularly characterize the bacterial community in BCMs at Shackleford Banks Island, North Carolina.
• To investigate fine-scale bacterial community structure across vertical mat layers.
• To correlate microbial composition with nutrient availability.

Main Methods:

• 16S rRNA gene metabarcoding for bacterial community analysis.
• Stable isotope analyses to assess nutrient cycling.
• Sampling across vertical strata and horizontal transects of BCMs.

Main Results:

• BCMs were primarily composed of Proteobacteria, Bacteroidota, Planctomycetota, Desulfobacterota, Verrucomicrobiota, and Cyanobacteria.
• Bacterial diversity and community composition differed significantly between vertical layers but not along horizontal transects.
• Observed trends in organic matter, carbon, and nitrogen availability corresponded with microbial community shifts across strata.

Conclusions:

• This study provides the first molecular characterization of the complete bacterial community in North Carolina BCMs.
• Vertical stratification significantly shapes microbial community structure and function within BCMs.
• Findings offer insights into the biogeochemical processes occurring within these important ecosystems.