Significant enrichment of aerobic methanotrophs drives rapid consumption of methane in hydrothermally impacted deep waters

Deep-sea hydrothermal vents release large amounts of methane gas from the Earth’s interior to the overlying ocean where it is microbially oxidized before reaching the atmosphere. However, the magnitude of aerobic methane oxidation and activity of methanotrophic communities in hydrothermal plume-impacted waters remain poorly constrained. Here we provide evidence that aerobic methanotrophy represents a prominent process that quantitatively mitigates methane emissions in hydrothermal plume-impacted waters. We found that plume dispersion at the Yokosuka vent field broadly enriched methane in water columns and stimulated highly active, metabolically versatile methanotrophic communities dominated by Methylomonadaceae (>65% of the RNA-based community), which emerged as the strong candidates that drove the elevated methane oxidation rates (up to 17.2 nmol L−1 day−1 at ~100 m from the vent). We estimated that total aerobic methane consumption across plume-impacted zones of the Okinawa Trough can reach 12.8 Gg CH4 yr−1. These findings highlight the significant role of aerobic methanotrophs in reducing the emissions of hydrothermally-derived methane to the atmosphere. Aerobic methanotrophs play a key role in reducing the emissions of methane released from hydrothermal vent, according to in-situ data from the Yokosuka vent field