‘Early Mars’ may have been habitable for methane-producing microbes

Life on Mars could have been very different from what we currently know on Earth: microorganisms consumed hydrogen and expelled methane.

Early Mars may have provided a favorable subsurface environment for microbial life that feeds on hydrogen and produces methane , says a model-based study published in Nature Astronomy .

The research  led by Boris Sauterey of the University of Arizona dates back to the Noachian period, more than 3.7 billion years ago.

A living Mars 

Until now, the evidence suggests that the Red Planet harbored – at least during part of its history – potentially favorable conditions for the development of life, however, science has rarely tried to quantitatively establish the probability of such a scenario.

The team presents a probabilistic assessment of the habitability of Mars for H2-based methanogens and quantifies their biofeedback on the planet’s atmosphere and climate.

The result is that subsurface habitability was “very likely,” and was limited primarily by the extent of ice cover on the surface.

The team modeled the interaction between the primitive environment on Mars and an ecosystem of methanogenic hydrogenotrophs (microorganisms that survive by consuming hydrogen and producing methane ), which are considered to be among the earliest forms of life on Earth.

On Mars , brine-saturated porous regolith would have created a physical space shielded from ultraviolet and cosmic radiation and provided a solvent, the authors note in the study.

In addition, the temperature below ground and the diffusion of a dense, reduced atmosphere could have supported simple microbial organisms that consumed H2 and CO2 as energy and carbon sources and produced methane as waste.

With a condition

The authors’ simulations predict that the Martian crust was a viable location for this ecosystem, as long as the surface was not entirely covered in ice.

In that case the predicted biomass production could have been comparable to that of Earth’s early ocean and have had a global cooling effect on the early climate of Mars , ending possible initial warm conditions, compromising the habitability of the surface. and forcing the biosphere deeper into the Martian crust.

Spatial projections from the research indicate that lowland locations at low and mid-latitudes are good candidates for discovering traces of this early life at or near the surface.

In fact, they identify three places: Hellas Planitia, Isidis Planitia, and Jezero Crater (where NASA’s Perseverance rover is currently working), as the best places to look for signs of this early methanogenic life near the surface of Mars . EFE