By Andrea Hargraves 
The underground world may have been teeming with microorganisms in the past. This is what was revealed by a new study published by French scientists last Monday (10).
Despite the encouraging results, researchers believe that if these simple life forms did exist, they would have altered the red planet’s atmosphere so profoundly that it An “ice age” could have started on Mars, which would have led to the extinction of these organisms.
Life – even simple life like microbes – “can actually cause them to die,” said the study’s lead author, Boris Souteri, a postdoctoral researcher at the Sorbonne.
In an email interview with The Associated Press, he said the results were “a bit grim, but I think they’re very encouraging.” “They challenge us to rethink the way the biosphere and its planet interact.”
Using climate and terrain models, Souteri and his team evaluated the so-called habitability From the crust of Mars about 4 billion years ago, when the planet was thought to be more hospitable and full of water.
The researchers argue that these methane-producing, hydrogen-eating bacteria could have thrived beneath the surface of Mars at that time, It is surrounded by several tens of centimeters of dirt that protects it from the incoming strong radiation.
As in early Earth, any ice-free region of Mars could be teeming with these organisms, according to Souteri.
According to the researcher, the supposedly hot and humid climate of early Mars was distorted by much of the hydrogen sucked up from the red planet’s thin, carbon dioxide-rich atmosphere.
With temperatures dropping to nearly minus 200 degrees Celsius, any organisms at or near the surface would likely have buried themselves even deeper in an effort to survive.
On the other hand, the researchers said, microbes on Earth may have helped maintain the temperature conditions here, given the nitrogen-dominated atmosphere.
Kaveh Pahlevan of the SETI Institute, an organization that studies the origin of life in the universe, said future climate models for Mars need to be considered with this research.
According to another study he led, Mars has been a wet planet with warm oceans for millions of years.
Rover Perseverance operates around a rocky outcrop called “Skinner Ridge” in Mars’ Jezero crater. Photo: NASA/Disclosure
During this period, the atmosphere was dense and rich in hydrogen, This causes it to retain heat and eventually lose it to space as a greenhouse gas.
The French study investigated the climatic effects of potential microbes when carbon dioxide dominated the Martian atmosphere, and thus not applicable to earlier times, Pahlifan said.
But what their study shows is that if [essa] The expert added in an email that life on Mars “during that period” would have a significant impact on the climate.
But what are the best places to look for traces of this past life?
French researchers propose a specific area: the undiscovered Hellas Planita, a plain located in the southern hemisphere of the planet, and the Jezero Crater, where the NASA probe is currently collecting rocks that will return to Earth in a few years.
Sauterey bets on this to investigate whether there is still life on our neighboring planet.
Is it possible that Mars today is inhabited by microscopic organisms descended from this early biosphere? He said. If yes, where?
*With information from The Associated Press.