THE first life forms on Mars may have been the architects of their own demise.
According to research, ancient Mars may have had an environment capable of supporting an underground world teeming with microscopic organisms.
But if they existed, these simple microbes would have altered the atmosphere so profoundly that they would have triggered a Martian ice age and wiped themselves out, the French team concluded.
The results offer a murky view of the ways of the cosmos.
“Life – even simple life, like microbes – can indeed often cause its own demise,” said the study’s lead author Boris Sauterey, now a post-doctoral researcher at the Sorbonne University.
“The results are a bit bleak, but I think they’re also very encouraging,” he added.
“They challenge us to rethink the way a biosphere and its planet interact.”
Sauterey and his team used climate and terrain models to assess the habitability of the Martian crust about 4 billion years ago.
Back then, the Red Planet was considered water-covered and much more hospitable than it is today.
The researchers suspected that hydrogen-eating, methane-producing microbes might have been thriving just below the surface at the time.
They are believed to have lived under several inches of soil, more than enough to protect them from strong incoming radiation.
Anywhere on Mars that is free of ice could be teeming with these organisms, just like early Earth, Sauterey says.
“However, the presumably humid, warm climate of early Mars would have been jeopardized by so much hydrogen being sucked out of the thin, carbon dioxide-rich atmosphere,” Sauterey said.
When temperatures dropped nearly minus 400 degrees Fahrenheit (minus 200 degrees Celsius), any organisms on or near the surface would likely have burrowed deeper to survive.
In contrast, given the nitrogen-dominated atmosphere, microbes on Earth may have helped maintain temperate conditions, the researchers said.
Kaveh Pahlevan of the SETI Institute said future models of the Martian climate must take French research into account.
Pahlevan recently led a separate study suggesting that Mars was born wet with warm oceans that lasted millions of years.
The atmosphere then would have been dense and composed mostly of hydrogen, serving as a heat-trapping greenhouse gas that was eventually transported to higher altitudes and lost in space, his team concluded.
“The French study examined the climate impact of possible microbes when the Martian atmosphere was dominated by carbon dioxide and is therefore not applicable to earlier times,” Pahlevan said.
“What their study makes clear, however, is that if (this) life had been present on Mars at that earlier time, it would have had a major impact on the prevailing climate,” he added in an email.
The best places to look for traces of this past life? The French researchers propose the unexplored crater Hellas Planita or Jezero on the northwestern rim of Isidis Planita.
That’s where NASA’s Perseverance rover is currently collecting rocks for return to Earth in a decade.
Next on Sauterey’s to-do list: investigate the possibility that microbial life might still exist deep within Mars.
“Could Mars still be inhabited today by microorganisms descended from this primitive biosphere?” he said. “If yes, where?”
The research was published in the journal Nature Astronomy.
Learn more about science
Want to learn more about the weird and wonderful world of science? From the moon to the human body, we’ve got you covered…
We pay for your stories! Do you have a story for The Sun Online Tech & Science Team? Email us at firstname.lastname@example.org
https://www.thesun.ie/tech/9555587/early-martians-wiped-out-life-ending-mars-event/ Early Martians may have wiped themselves out in a “life-ending Martian event,” a shock study reveals