The hunt for life on Mars may have just got a serious shot in the arm. As reported in the journal Extremophiles, there’s a good chance that micro-organisms could survive in exceedingly harsh conditions on the Red Planet for as long as 20 million years.
A research team from Lomonosov Moscow State University decided to dig around in the permafrost up in the Russian Arctic. This snow crystal-infused soil is impregnated with microbes, including plenty that break down organic matter and turn it into methane.
These hardy little beasties are thought to be the type that would survive on Mars, potentially locked up in the underground caches of frozen water. Taking samples of these microbial colonies, the researchers put them in chambers that simulate the conditions on the Martian surface.
At a glance, it seems impossible that anything could survive over there. Sure, the Earth-like atmosphere it once had has been stripped away by a failing magnetic field and powerful solar winds. Yes, there’s not as much free-flowing water as there once was.
The atmospheric pressure is still horrifically low, and the surface temperatures plunge from -73°C (-100°F) near the equator to -125°C (-195°F) at the poles. The surface itself is bombarded with powerful solar radiation, enough to stop much of life proliferating.
However, despite putting the permafrost microbes through this chilly, heavily irradiated apocalypse, they survived – albeit with some caveats.
Radiation was the key factor here. While plenty of communities remained unchanged when assaulted with gamma radiation, the population of bacteria cultured on a bed of nutrients decreased tenfold. Members of the archaea kingdom – not quite bacteria, but not too far off – decreased threefold.
They didn’t completely die out though, which is what matters.
Certain species appear to be more resilient than others, and as others reduced in number, they multiplied and took over. One particular genus, Arthrobacter, showcased exceptional radiation defenses.
Based on these experiments, the team reason that such microbes could survive for around 2 million years living on Mars' surface, 3.3 million years just below the surface, and at least 20 million years at a depth of five meters (16.4 feet). The deeper they are, the less radiation they receive, and the longer they live.
If this all still sounds implausible, remember that Earth itself is a microbial world.
Thanks to their ability to exist in the most inhospitable environments, microbes can be found literally everywhere, from acidic geothermal pools to within the crust itself. They can even be found suspended within gigantic crystals in superheated caves.
It makes sense then that Mars is likely to have featured – or still feature – microbial beings, and this research suggests that, despite the harsh conditions, it’s more probable than we may think. Life, uh, finds a way, remember.