Subsurface microbial methanotrophic mats in the Black Sea

Area of Science:

• Marine microbiology
• Geochemistry
• Archaea research

Background:

• The Black Sea is an anoxic marine environment with active gas seeps.
• Microbial mats are known to form in various marine settings.
• Previous research has identified microbial reefs, but their initial formation stages are less understood.

Purpose of the Study:

• To investigate the microbial communities and metabolic processes within subsurface gas seep sediments.
• To characterize the role of ANME-1 archaea in methane and sulfate cycling.
• To determine if observed microbial mats represent an early stage of microbial reef development.

Main Methods:

• Sediment core collection from a Black Sea gas seep.
• Microbial community analysis using molecular techniques (e.g., 16S rRNA sequencing).
• Geochemical analysis of methane and sulfate concentrations and consumption rates.

Main Results:

• Discovery of a nodule-shaped microbial mat in subsurface sediments.
• The mat was primarily composed of ANME-1 archaea.
• Simultaneous consumption of methane and sulfate was observed within the mat.

Conclusions:

• Subsurface microbial mats in gas seeps are viable ecosystems.
• ANME-1 archaea play a key role in coupled methane and sulfate cycling in these environments.
• These mats are proposed as the initial developmental stage of previously documented microbial reefs.