Science Alert June 18, 2021
As marine methane seeps, vast quantities of methane move through the shallow subseafloor, where it is largely consumed by microbial communities. A team of researchers in the US (Harvard University, DOE, USGS, UCLA, Caltech) conducted a continental-scale survey of seven geologically diverse seafloor seeps and found that carbonate rocks from all sites host methane-oxidizing microbial communities with substantial methanotrophic potential. In laboratory-based mesocosm incubations, chimney-like carbonates from the coast of Southern California exhibited the highest rates of anaerobic methane oxidation measured to date. After a thorough analysis of physicochemical, electrical, and biological factors, they attributed this substantial metabolic activity largely to higher cell density, mineral composition, kinetic parameters including an elevated Vmax, and the presence of specific microbial lineages. Their data suggested that other features, such as electrical conductance, rock particle size, and microbial community alpha diversity, may influence a sample’s methanotrophic potential, but these factors did not demonstrate clear patterns with respect to methane oxidation rates. Based on their findings they suggest that rock-hosted methanotrophy may be an important contributor to marine methane consumption…read more. Open Access TECHNICAL ARTICLE
Confocal microscopy images of an intact interior portion of sample PD R1… Credit: PNAS June 22, 2021, 118 (25) e2006857118Â