Anaerobic oxidation of methane: progress with an unknown process

Area of Science:

• Biogeochemistry
• Microbiology
• Environmental Science

Background:

• Methane is a significant greenhouse gas, contributing 20% to postindustrial global warming.
• Microbial processes drive 85% of global methane production and 60% of consumption.
• Key microbial groups regulating methane fluxes include aerobic methanotrophic bacteria, methanogenic archaea, and anaerobic methanotrophic archaea (ANME).

Purpose of the Study:

• To review the current understanding of anaerobic oxidation of methane (AOM).
• To identify and discuss the key microbial catalysts of AOM, specifically ANME.
• To highlight knowledge gaps in the study of AOM and ANME.

Main Methods:

• Literature review of biogeochemical and microbial studies on methane cycling.
• Focus on anaerobic oxidation of methane (AOM) and its microbial mediators.
• Analysis of the role of anaerobic methanotrophic archaea (ANME) in AOM.

Main Results:

• ANME are key archaeal lineages driving AOM.
• AOM is a critical process for methane consumption in anoxic environments.
• The net reaction of AOM involves methane and sulfate, producing bicarbonate and sulfide.

Conclusions:

• ANME are specialized archaea that derive energy from AOM.
• Understanding ANME and AOM is vital for comprehending global methane budgets.
• Further research is needed to fully elucidate the microbial processes and agents of AOM.