In the hunt for alien life, the discovery of salty water on Mars was one of the most important breakthroughs we had in the past few years. But while scientists and space agencies plan missions to explore the Martian water, new research suggests we should focus on the salt as much as the water.
According to Alfonso Davila from SETI and Dirk Schulze-Makuch from Washington State University, dried salt planes might have been where the last life forms of Mars lived, and we should investigate those areas in future missions.
In their paper, published this month in Astrobiology, they investigate how likely it is for simple bacteria to have adapted and survived in an increasingly dry environment as the water on Mars receded into the ground. The environment presented unique challenges for organisms, as the increase in salt, strong ultraviolet radiation, and dryness would have culled most simple organisms.
Yet, the researchers think that life might have colonized the land on Mars, given the extensive period in which the planet had flowing water. While we are yet to find definitive proof of life on the Red Planet, let alone land colonization, the study authors present an intriguing case. The large northern ocean and the crater lakes on the south side of the planet had huge shorelines, where communities of organisms might have developed the right skills to move from wet to dry environments like some organisms have done on our planet.
“The ecological transitions that occur in Earth’s deserts with increasing dryness can inform us as to where the last Martian near-surface ecosystems may have existed or still exist,” they say in the paper.
The potential for life in salt deposits is an interesting prospect to consider. Not only could we find fossilized bacteria in ancient basins, but if life adapted to the complex conditions, it might have survived in the periodical rivulets of briny water around Mars' equator.