Simulating the Marine Methane Cycle for Current Arctic Conditions
Warming of the Arctic could release substantial amounts of methane, a potent greenhouse gas, now buried in the cold sediments of the Arctic continental shelves. However, the amount of methane penetrating the surface waters to the atmosphere depends on biogeochemical interactions with seawater. DOE scientists have developed a model for the fate of potential methane clathrate release in the contemporary Arctic, and their results suggest that there are numerous obstacles to the release of methane to the atmosphere. Methane released from clathrates did not penetrate far from emission sites due to biogeochemical reactions. These reactions have products that can be deleterious to the methane consumers. However, even if methane builds up in the Arctic basin due to reductions of marine methane-consumers, freshened polar surface waters act as a barrier to atmospheric transfer and the methane and its byproducts are diverted into the deep ocean return flow. This study highlights the protective obstacles that inhibit release of methane from Arctic sediments to the atmosphere; however, uncertainties in high-latitude clathrate abundance, buoyant effluent rise through the water column, representation of the general circulation, and bacterial growth kinetics warrant further research.
Elliott, S., M. Maltrud, M. Reagan, G. Moridis, and P. Cameron-Smith. 2011. “Marine Methane Cycle Simulations for the Period of Early Global Warming,” Journal of Geophysical Research 116, G01010, doi:10.1029/2010JG001300.