Brown: Ancient Mars Had Right Conditions for Underground Life

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Brown: Ancient Mars Had Right Conditions for Underground Life

Post by bystander » Mon Sep 24, 2018 5:04 pm

Ancient Mars Had Right Conditions for Underground Life
Brown University | 2018 Sep 24

A new study shows that the breakdown of water molecules trapped in ancient Martian rocks likely produced enough chemical energy to sustain microorganisms for hundreds of millions of years beneath the Red Planet’s surface.

A new study shows evidence that ancient Mars probably had an ample supply of chemical energy for microbes to thrive underground.

“We showed, based on basic physics and chemistry calculations, that the ancient Martian subsurface likely had enough dissolved hydrogen to power a global subsurface biosphere,” said Jesse Tarnas ... “Conditions in this habitable zone would have been similar to places on Earth where underground life exists.”

Earth is home to what are known as subsurface lithotrophic microbial ecosystems — SliMEs for short. Lacking energy from sunlight, these subterranean microbes often get their energy by peeling electrons off of molecules in their surrounding environments. Dissolved molecular hydrogen is a great electron donor and is known to fuel SLiMEs on Earth.

This new study shows that radiolysis, a process through which radiation breaks water molecules into their constituent hydrogen and oxygen parts, would have created plenty of hydrogen in the ancient Martian subsurface. The researchers estimate that hydrogen concentrations in the crust around 4 billion years ago would have been in the range of concentrations that sustain plentiful microbes on Earth today.

The findings don’t mean that life definitely existed on ancient Mars, but they do suggest that if life did indeed get started, the Martian subsurface had the key ingredients to support it for hundreds of millions of years. The work also has implications for future Mars exploration, suggesting that areas where the ancient subsurface is exposed might be good places to look for evidence of past life. ...

Radiolytic H2 Production on Noachian Mars: Implications for Habitability and Atmospheric Warming ~ J.D. Tarnas et al
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