Ocean Microbes Methane Emission Control
Seafloor Microbes Use “Protein Wires” to stop Methane Emissions
Key Takeaways:
Methane Sink: Marine sediments act as a crucial sink for methane, a potent greenhouse gas, preventing most of it from escaping into the atmosphere.
Microbial Partnership: this methane removal is driven by a partnership between anaerobic methanotrophic archaea and sulfate-reducing bacteria.
Electron Transfer: Researchers have discovered how these microbes work together – through direct electron transfer via protein “wires.”
Redox Conduction: Lab experiments show electrons move between the archaea and bacteria across tiny gaps using proteins, specifically likely multiheme cytochrome c proteins.
Importance: This revelation clarifies a vital process in the ocean’s methane budget and highlights the role of these microbial communities as “natural sentries” against methane release.
Details:
Scientists, led by Hang Yu of Peking University, have gained a clearer understanding of how seafloor microbes prevent methane from entering the atmosphere. Methane is a powerful heat-trapping gas,but marine sediments effectively neutralize most of it through a process called anaerobic oxidation of methane.
This process relies on a symbiotic relationship:
Archaea: These microbes remove methane in the absence of oxygen.
Bacteria: They partner with sulfate-reducing bacteria, which use sulfate (a common salt in seawater) rather of oxygen.
The team conducted experiments using samples from methane seeps in the Mediterranean, Guaymas Basin, and off the california coast. They found that electrons stripped from methane by the archaea are transferred to the bacteria,who then use sulfate to complete the process.
Using microelectrodes, researchers tracked electrical signals between the microbial clusters, revealing that electrons move across incredibly small gaps (0.0002 inch) via proteins. The signals were disrupted by heat,oxygen exposure,and chemical treatments that affect proteins,indicating proteins are the key to this electron transfer.
the most likely mechanism involves multiheme cytochrome c proteins, which act as “wires” to carry electrons between cells. This discovery confirms that electrons can travel far enough to connect methane oxidation with sulfate reduction, effectively neutralizing the methane.
Sources:
https://www.earth.com/news/seafloor-microbes-use-protein-wires-to-stop-methane-emissions/
https://pubmed.ncbi.nlm.nih.gov/35714268/
https://www.earth.com/news/cutting-methane-emissions-could-quickly-slow-global-warming/
https://www.earth.com/news/rising-methane-emissions-threaten-earths-habitability/
* https://www.earth.com/news/methane-leaks-surge-amid-record-fossil-fuel-production/