Identifying putative subsurface microbial drivers of methane flux on Earth and Mars
Colloquium
Two decades of observing methane on Mars have generated data indicative of a dynamic, geochemical system producing both distinct pulses known as plumes separated by slow background seepage. These observations suggest as of yet unknown geochemical and potentially geobiological methane sources and sinks. On Earth, microorganisms are critical drivers of the methane cycle, both producing and consuming methane. Indeed, microbial consortia oxidizing methane for energy in deep ocean methane seeps are responsible for mitigating the release of catastrophic amounts of methane into the atmosphere. Wolf Spring on Axel Heiberg Island, Nunavut is a hypersaline cold spring methane seep and the only known terrestrial permafrost hosted methane seep – a natural laboratory and analogue for putative subsurface brines and methane seeps on Mars. Recently, genetic evidence has suggested the presence of the same methane oxidising microorganisms in Wolf Spring as those found in submarine seeps. Here I will discuss a multi-disciplinary effort including field site characterization, microbial microcosm experiments, and in situ methane monitoring to identify methane driven microbial metabolisms not only critical to understanding methane flux in the Arctic, but also as possible drivers to the methane cycle on Mars.