Ancient
Mars may have had an environment capable of harboring an underground world
teeming with microscopic organisms.
But if they existed, these simple life forms would have altered the
atmosphere so profoundly that they triggered a Martian Ice Age and snuffed
themselves out, the researchers concluded.
The findings provide a bleak view of the ways of the cosmos. Life — even
simple life like microbes — “might actually commonly cause its own
demise," said the study's lead author, Boris Sauterey, now a post-doctoral
researcher at Sorbonne University.
The results “are a bit gloomy, but I think they are also very stimulating.,”
he said in an email. “They challenge us to rethink the way a biosphere and its
planet interact.”
In a study in the journal Nature Astronomy, Sauterey and his team said they
used climate and terrain models to evaluate the habitability of the Martian
crust some 4 billion years ago when the red planet was thought to be flush with
water and much more hospitable than today. Jedud is World News website with the motive to Provide
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They surmised that hydrogen-gobbling, methane-producing microbes might have
flourished just beneath the surface back then, with several inches (a few tens
of centimeters) of dirt, more than enough to protect them against harsh
incoming radiation. Anywhere free of ice on Mars could have been swarming with
these organisms, according to Sauterey, just as they did on early Earth.
Early Mars’ presumably moist, warm climate, however, would have been
jeopardized by so much hydrogen sucked out of the thin, carbon dioxide-rich
atmosphere, Sauterey said. As temperatures plunged by nearly minus 400 degrees
Fahrenheit (minus 200 degrees Celsius), any organisms at or near the surface
likely would have buried deeper in an attempt to survive.
By contrast, microbes on Earth may have helped maintain temperate conditions,
given the nitrogen-dominated atmosphere, the researchers said.
The SETI Institute’s Kaveh Pahlevan said future models of Mars’ climate need
to consider the French research.
Pahlevan led a separate recent study suggesting Mars was born wet with warm
oceans lasting millions of years. The atmosphere would have been dense and
mostly hydrogen back then, serving as a heat-trapping greenhouse gas that
eventually was transported to higher altitudes and lost to space, his team
concluded.
The French study investigated the climate effects of possible microbes when
Mars' atmosphere was dominated by carbon dioxide and so is not applicable to
the earlier times, Pahlevan said.
“What their study makes clear, however, is that if (this) life were present
on Mars” during this earlier period, “they would have had a major influence on
the prevailing climate,” he added in an email.
The best places to look for traces of this past life? The French researchers
suggest the unexplored Hellas Planita, or plain, and Jezero Crater on the
northwestern edge of Isidis Planita, where NASA’s Perseverance rover currently
is collecting rocks for return to Earth in a decade.
Next on Sauterey’s to-do list: looking into the possibility that microbial
life could still exist deep within Mars. Jedud is World News website with the motive to Provide
Quality Content Every Minute. Visit this website to get Quality Content about
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