oastal ecosystems are estimated to contribute up to 75% of global marine methane emissions, despite covering only 16% of the marine realm. (1,2) Increasing exposure to eutrophication and deoxygenation, (3,4) stimulates benthic methane fluxes, making microbial methane removal in the water column a crucial contributor to the mitigation of methane emissions. (5−7) In stratified waters, aerobic methane-oxidizing bacteria (MOB) populate the oxygen-methane counter gradient. (8,9) Genomic analysis of the MOB communities and laboratory experiments show versatile metabolic adaptations of MOB genera to a broad range of oxygen concentrations, which can extend the ecological niche of the MOB even into the anoxic water layers. (10−12) There, the putatively aerobic methane oxidizers can potentially oxidize methane with alternative electron acceptors such as nitrate and metal oxides, contributing to water column methane removal even under anaerobic conditions. (10,12,13) As coastal waters are particularly susceptible to prolonged stratification periods and resulting bottom water deoxygenation, (4,14) such potential anaerobic methane removal may become a more important process in mitigating methane emissions in the future. However, longer-term stratified marine basins are not only exposed to deoxygenation, but also to the accumulation of sulfide (euxinia). However, it is still unclear how altered stratification regimes and associated euxinia impact water column methane removal in these systems...