There’s ice on Mars, covered in dust. It also exists on Earth, and microscopic life can exist there. Now scientists are trying to find out whether the same is possible on the red planet, where the rarefied atmosphere prevents the most important substance for terrestrial organisms from existing in a liquid state.
Life in Martian ice
So far, scientists haven’t found any undeniable traces of life on Mars. But they suggest that it exists there, hiding in the ice. At least that’s what the authors of a new study published in the journal Communications Earth & Environment claim.
In general, there are two types of ice on Mars: carbon dioxide and water ice. The first one melts every summer, and it is responsible for the white caps at the planet’s poles appearing and disappearing. Water ice, on the other hand, was formed long ago when the planet’s climate was much warmer, and it hasn’t melted since. Most of it is at the poles of Mars, but scientists suspect it should be beneath the surface in its temperate latitudes, too.
In the ice itself, living organisms cannot exist in an active state. However, as it melts, small pools can form within it, literally teeming with microscopic bacteria, algae and fungi.
Dusty ice
Scientists are especially counting on the ice that is contaminated with dust. Microscopic solid particles prevent the sun’s rays from reaching the frozen water. But being dark, they absorb energy and heat up well. Due to this, microscopic pools are formed directly underneath them.
Back in 2012, researchers studied deposits of such ice in Canada and confirmed the existence of a developed biome within it. Theoretically, the same could be expected on Mars, but there’s a problem. The air pressure is very low. Therefore, water moves from the solid state to the gaseous state, bypassing the liquid state, when the ice melts.
Scientists believe that the presence of a layer of dust can prevent the instantaneous evaporation of water and preserve the environment for microscopic life. However, dusty ice itself is also good at hiding. Its existence at the bottom of gullies in the temperate zone of Mars was proven only in 2021. This was done by the same group who are the authors of the present study.
The key question now is whether sunlight can penetrate the dust layer efficiently enough to supply energy to the algae and cyanobacteria that should be at the base of the food pyramid.
In the new study, scientists simulated the situation on a computer and got the answer. According to it, even through the dust layer, sunlight on Mars should penetrate the ice to a depth of up to 3 meters, so the existence of life in microscopic reservoirs is quite possible.
According to phys.org
