Life on Mars was possible – but microbes made the red planet uninhabitable

Mars is the planet explored by most human equipment.  Many orbiters orbit the red planet, and several rovers and other research devices are also active on its surface.

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Of: Tanya Banner


Mars may have once been home to life – until it caused climate change and made its own planet uninhabitable. This shows a new study.

Tucson – When it comes to Mars, many questions preoccupy researchers: Was there or is there life on the red planet? How did Mars lose its water and atmosphere? And how did the Red Planet get so cold? A study by French and American researchers could now have answered two of these questions at the same time – and provided a surprising explanation.

The research team led by astrobiologist Boris Sauterey (University of Arizona and University Paris Sciences et Lettres) assumed for the study that Mars was habitable more than 3.7 billion years ago and that micro -organisms lived on the planet at that time, which spread by feeding on hydrogen. and producing methane in the process (called methanogenic hydrogenotrophs). According to research, the situation on Earth was very similar: researchers speculate that methanogenic hydrogenotrophs were among the first creatures on Earth and that their production of methane warmed and stabilized the Earth’s climate. As a result, more complex life forms emerged.

Study: For a time, life was said to swarm on Mars

“We believe that Mars was then slightly colder than Earth, but not as cold as it is today, with average temperatures likely above the freezing point of water,” said co-author Regis Ferrière in a statement from the University of Arizona. “While modern-day Mars has been described as an ice cube covered in dust, we envision early Mars as a rocky planet with a porous crust, saturated with liquid water that probably formed lakes and rivers, perhaps even seas or oceans.”

Lead author Sauterey explains the portal reverse: “We know that Mars was warm in the beginning, so we wanted to provide the biological explanation for this early climate.” But instead, the researchers found that the opposite of what happened on Earth happened on Mars: In the researchers’ simulation, the red planet had been teeming with subterranean life in the form of methanogenic microorganisms since several hundred thousand years.

Climate change on Mars: microbes may have made the planet uninhabitable

However, more and more methane entered the atmosphere, and methane’s interactions with the Martian atmosphere and the salty polar ice caps continued to cool the planet. “By removing hydrogen from the atmosphere, the microbes would have significantly cooled the planet’s climate,” says Sauterey. In the simulation, Mars was almost completely covered in a layer of ice within half a million years.

Researchers are looking for liquid water on Mars.  (icon picture)
Researchers are looking for liquid water on Mars. (Iconic image) © IMAGO/Marcos Osorio

Thus, climate change caused by life on Mars may have contributed early on to making the planet’s surface uninhabitable. “The problem these microbes would then have faced is that the Martian atmosphere would have basically disappeared, completely depleted, so their energy source would have disappeared and they would have had to find an alternative energy source,” Sauterey explains. “Also, the temperature would have dropped significantly, and they would have had to go much deeper into the crust. At the moment, it is very difficult to say how long Mars would have remained habitable.”

Mars: life may have survived in deeper layers

But in some low-lying regions, life near the surface of Mars may have persisted for at least some time, according to the study, published in the journal natural astronomy has been published. The researchers identify three regions on Mars where there is a high probability of finding traces of early methanogenic life near the Martian surface:

  • Hellas Planitia
  • Isidis Planitia
  • Jezero Crater

Life on Mars? NASA rover monitors region of interest

One of the regions mentioned – Jezero Crater – has been examined by NASA’s “Perseverance” rover since March 2021. The Mars rover has just discovered organic matter there, delighting the research community with the prospect of bring matter to Earth in the years to come.

Space Bulletin

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Lead author Sauterey takes a somewhat bleak view of his study’s findings: “The fact that a very primitive biosphere could have dramatically cooled the climate on Mars, making it potentially uninhabitable, suggests that one of the limiting factors the community of life in the universe can be life itself,” he points out. reverse alluding to humanity and climate change on earth. “Perhaps it is a common fate of life in the universe to self-destruct.” (tab)

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