The Long-Term Relationship between Microbial Metabolism and Greenhouse Gases

The production and consumption of the potent greenhouse gases, nitrous oxide and methane, are largely controlled by microorganisms that have long been assigned to defined functional guilds. However, our understanding of how microbial and biogeochemical processes interact to control the flux of these gases has expanded in recent years. The consumption and production of nitrous oxide and methane are functionally intertwined and engage a range of other biogeochemically active molecules from oxic to anoxic ecosystems. Abiotic processes, such as reaction of nitrogen oxides with metals, have a strong influence on microorganisms and play an equally significant role in greenhouse gas flux. The complex enzymology and physiology of microbial greenhouse gas metabolism are explored and discussed in the context of geochemistry and climate change.