Methanogens, which belong to the domain Archaea, are among the simplest and oldest organisms on Earth. They use hydrogen as their energy source and carbon dioxide as their carbon source to metabolize and produce methane. Methanogens live in swamps and marshes, but can also be found in the gut of cattle, termites and other herbivores as well as in decaying matter.
These simple organisms don’t require oxygen or organic nutrients to survive, as well as don’t undergo photosynthesis, indicating that methanogens are ideal for living in sub-surface environments such as those on Mars. During this study, researchers found that in a laboratory setting, four species of methanogens survived low-pressure conditions that simulated a subsurface liquid aquifer on Mars.
"These organisms are ideal candidates for life on Mars," doctoral student Rebecca Mickol, who helped lead the research, said in a statement. "All methanogen species displayed survival after exposure to low pressure, indicated by methane production in both original and transfer cultures following each experiment. This work represents a stepping-stone toward determining if methanogens can exist on Mars."
In previous research, Mickol also discovered that two species of methanogens survived Martian freeze-thaw cycles. NASA scientists have been using various instruments, including the Opportunity and Curiosity rovers – in recent years to find signs of life (water) on our neighboring planet and determine whether the surface was once habitable. In fact, scientists may even land on the crater in the future with NASA’s Mars 2020 rover.
And now, with this new discovery about methanogens, the possibility that Mars could support life seems more plausible than ever.