Anaerobic oxidation of methane with conditions of increased temperature and extra sulfate supply

Abstract

Anaerobic oxidation of methane (AOM) coupled with sulfate reduction (SR) is an important process in cold-seep ecosystems to prevent methane emitted from the seafloor to the atmosphere. However, how the temperature and sulfate in seep habitats drive the SR-AOM process and further affect the methane cycles remains unknown. We simulated the habitat differences in sulfate and temperature using a high-pressure bioreactor system with a fed-batch mode for in vitro incubation of seep sediment. We found that SR-AOM was significantly affected by increased temperature (15°C). The AOM activity was increased by sulfate supply (+15 mM), even at a low temperature (8°C). Our findings provide a new insight into the methane budget in cold seeps.