Anaerobic oxidation of methane
Anaerobic oxidation of methane (AOM) is a methane-consuming microbial process occurring in anoxic marine and freshwater sediments. AOM is known to occur among mesophiles, but also in psychrophiles, thermophiles, halophiles, acidophiles, and alkophiles.
Source: Wikipedia — Anaerobic oxidation of methane (CC BY-SA 4.0)