The amount of methane found in the plumes was a surprise - because it can't be explained by known geochemical processes. Which could have implications for life there, such as microbes - methanogens - that 'eat' dihydrogen and produce methane. On Earth, methane can be produced through hydrothermal activity, but at a slow rate. First, the researchers assessed what hydrothermal production of dihydrogen would best fit Cassini's observations, and whether this production could provide enough \"food\" to sustain a population of Earthlike hydrogenotrophic methanogens. The results suggest that even the highest possible estimate of abiotic methane production – or methane production without biological aid – based on known hydrothermal chemistry is far from sufficient to explain the methane concentration measured in the plumes.