Martian Soil More Toxic To Life Than Before

Posted July 08, 2017

The researchers exposed soil from the Atacama Desert containing perchlorates to UV light in environmental conditions much like those on Mars.

The findings mean that damp streaks on the Martian surface that have been spotted from orbit may not be prime spots to find alien microbes.

Although it sounds alarming, researchers of the paper also said there is some good news in their findings.

The discovery of the presence of perchlorates on Mars several years ago nearly dashed all hope that scientists had of finding signs of life on the planet (if it had existed) as these chemical compounds are powerful oxidizing agents. Since then, other spacecraft have confirmed the presence of the compounds.

But the latest study, published in the journal Scientific Reports, suggests that in the presence of ultraviolet light perchlorate is not so microbe-friendly. Scientists have studied compounds within Martian soil and discovered that they are toxic when combined with Mars' UV rays.

In order to determine whether the found substance is good or bad for life, postgraduate student Jennifer Wadsworth and Professor Charles Cockell, both of the University of Edinburgh's School of Physics and Astronomy made a decision to recreate Mars conditions and soil to see whether Earth friendly bacteria can survive.

Wadsworth and astrobiologist Charles Cockell found that when perchlorates are exposed to ultraviolet light, they kill bacteria twice as fast as UV light alone.

And it's strong enough to kill off life even at the bacterial level, a study found. The irradiated cells in the perchlorate solution were completely sterilized within 30 seconds.

Although it seems pretty obvious that life on Mars wouldn't be necessarily very fulfilling or exciting, considering the extreme cold, radiation and the carbon dioxide made atmosphere, it has still not stopped humans to try and look for life there in hopes that one day maybe we can colonize the red planet.

The findings could have implications for planetary protection, specifically concerning the potential contamination of Mars by robotic and human exploration. The researchers also said that two other components on the Martian surface (iron oxides and hydrogen peroxide) may act alongside the perchlorates resulting in a 10 times increase in bacteria death.

Wadsworth: I can't speak for life in the past. "As far as present life, it doesn't rule it out but probably means we should look for life underground where it's shielded from the harsh radiation environment on the surface".