An analysis of meteorites from Mars shows that there are substances beneath the planet's surface that can sustain the life of microorganisms. Earth microbes live in a similar way in some places.
While the Perseverance rover is looking for traces of past life on the surface of the Red Planet, new research indicates that the area below the surface may be a good place to look for organisms living there today.
Well, scientists from Brown University studied the chemical composition of Martian meteorites - pieces of rock that were ejected from Mars and eventually ended up on Earth.
The analysis showed that when in constant contact with water, these rocks can produce the chemical energy that allows microorganisms to live, similar to the way they do at great depths on Earth.
The studied meteorites may, according to scientists, constitute a sample representative of a large part of the Martian crust, which means that a large part of the planet's subsurface is suitable for life support.
"The important conclusions for the scientific exploration of the layers below the surface are that wherever there is groundwater on Mars, there is a good chance of accessing enough chemical energy to sustain microbial life," says Dr. Jesse Tarnas.
"We do not know if life ever arose under the surface of Mars, but if so, we believe that it would have the energy at its disposal that would allow it to survive to this day" - adds the researcher.
Over the past few decades, it has been discovered on Earth that many organisms live deep beneath the surface, which, deprived of access to light, draw energy from the products of chemical reactions that occur when water comes into contact with rocks.
One such reaction is radiolysis. It occurs when the radioactive elements of the rock cause the breakdown of water molecules into hydrogen and oxygen. The released hydrogen dissolves in the water present, while some minerals such as pyrite absorb the oxygen to form sulphate.
Microbes can absorb hydrogen dissolved in water and use it as fuel in reaction with the oxygen in the sulfates.
For example, in Canada's Kidd Creek Mine, these types of microbes have been found almost 2 km deep in water that has not been reached by the sun for over a billion years.
In Martian meteorites, researchers found nutrients needed for radiolysis in sufficient quantities to support life.
This was especially true of regolith breccia - 3.6 billion years old fragments of the Red Planet's crust.
There is no tectonic plate movement on Mars, so the ancient sites of the debris have remained largely intact until now.
The authors of the discovery argue that it is an argument for sending a mission to look for the present life beneath the surface of Mars.
Previous research has already identified traces of active groundwater systems on the planet. There is a considerable probability that such systems still exist today.
For example, one recent study pointed to the possible existence of an underground lake under an ice sheet.
Naturally, sub-surface research will be more difficult than exploration so far, but, in the authors' opinion, it is not as challenging as it might seem.
According to them, the advances in drilling technology will soon make it possible to penetrate deep under the surface.
"The subsurface layers are one of the next frontiers in the study of Mars. We have already analyzed the atmosphere, made surface maps at different wavelengths of light, and landed on the surface in several places. Work is underway telling us a lot about the planet's past "- reminds one of the researchers, Prof. Jack Mustard.
"However, if we want to think about the possibility of today's presence of life, the area below the surface is where the most things can happen," he adds.
More information on this subject: https://www.liebertpub.com/doi/10.1089/ast.2020.2386 (PAP)
Author: Marek Matacz