Mars: Life was probably possible - until climate change began

Created: 2022-10-18 09:43

By: Tanya Banner

Mars was capable of supporting life - until microbes caused climate change and made its own planet uninhabitable.

Tucson – When it comes to Mars, there are many questions that concern researchers: Was 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 – and provide a surprising explanation, as fr.de reports.

The research team led by astrobiologist Boris Sauterey (University of Arizona and Université Paris Sciences et Lettres) assumed for the study that Mars was habitable more than 3.7 billion years ago and that microorganisms lived on the planet at that time, which spread from Feeding on hydrogen and producing methane in the process (called methanogenic hydrogenotrophs).

According to research, the situation on Earth was very similar: Researchers assume that methanogenic hydrogenotrophs were among the first creatures on Earth and that their methane production warmed and stabilized the Earth's climate.

As a result, more complex life forms emerged.

Study: For some time, life was said to have swarmed on Mars

"We believe that Mars was then slightly cooler than Earth, but not nearly as cold as it is today, with average temperatures likely exceeding the freezing point of water," said co-author Regis Ferrière in a statement from the University of Arizona.

"While present-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 likely formed lakes and rivers, perhaps even seas or oceans. "

Mars: These rovers and spacecraft explore the red planet

View photo gallery

Lead author Sauterey explains to the

portal : "We know that Mars was warm early on, so we wanted to provide the biological explanation for this early climate." But instead, the researchers discovered that Mars was the opposite of that what happened on earth happened: In the researchers' simulation, the red planet was teeming with subterranean life in the form of methanogenic microorganisms for several hundred thousand years.

Climate change on Mars: Microbes may have made planet uninhabitable

However, more and more methane entered the atmosphere and interactions of the methane with the Martian atmosphere and the salty ice caps of the poles continued to cool the planet.

"By removing hydrogen from the atmosphere, the microbes would have drastically cooled the planet's climate," explains Sauterey.

In the simulation, Mars was almost completely covered by a layer of ice within half a million years.

So the climate change caused by life on Mars may have contributed to making the planet's surface uninhabitable very early on.

"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," explains Sauterey.

“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."

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The red planet Mars is being explored by several NASA rovers.

(Archive image) © Nasa/Imago

Mars: Life may have survived in deeper layers

But in some low-lying regions, life may have survived near the surface of Mars for at least some time, the study, published in the journal

, says .

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 surveys region of interest

One of the regions mentioned - Jezero Crater - has been examined by the NASA rover "Perseverance" since March 2021.

The Mars rover just recently discovered organic material there, delighting the research community with the prospect of bringing the material to Earth in the years to come.

Lead author Sauterey has a somewhat somber view of his study's findings: "The fact that a very primitive biosphere could have greatly cooled the climate on Mars, potentially rendering it uninhabitable, suggests that one of the limiting factors for the commonality of the Life in the universe may be life itself,” he told

, alluding to humanity and climate change on Earth.

"Perhaps it is a common fate of life in the universe to self-destruct." (tab)