Potential for microbial methanethiol-dependent dimethylsulfide production in different marine sediments

Area of Science:

• Marine microbiology
• Biogeochemical cycles
• Climate science

Background:

• Dimethyl sulfide (DMS) is vital for sulfur cycling and climate regulation.
• Microbial methylation of hydrogen sulfide (H2S) and methanethiol (MeSH) are key DMS production pathways.

Purpose of the Study:

• Investigate microbial DMS production in diverse marine sediments.
• Identify the microbial taxa and pathways responsible for DMS synthesis.
• Explore the role of H2S and MeSH in DMS formation.

Main Methods:

• Culture-dependent and -independent microbiological techniques.
• Metagenomic analysis to identify DMS-producing genes and taxa.
• Analysis of sediments from nearshore, deep-sea, and cold-seep environments.

Main Results:

• DMS production was confirmed across all studied sediment types with MeSH addition.
• High abundance of the mdd gene was observed in pelagic deep-sea and nearshore sediments.
• Previously unknown Mdd-encoding taxa and potential novel Mdd enzymes were identified.
• A significant alternative pathway converting H2S to MeSH was discovered.

Conclusions:

• Marine sediments harbor a diverse and prevalent microbial pathway for DMS production.
• The identified alternative H2S to MeSH pathway is a significant MeSH source.
• Further research is needed to fully characterize Mdd-positive microbial communities and their roles.