This bactericidal effect is apparently due to the presence of iron oxides and hydrogen peroxide in Martian soil which "act in synergy with irradiated perchlorates to cause a 10.8-fold increase in cell death when compared to cells exposed to UV radiation after 60seconds of exposure". For future Martian civilization, materials and even humans will be sent to the planet. And researchers have been optimistic that their presence could support bacterial life on Mars. Since their discovery there several years ago, scientists have speculated on the influence that perchlorates may have on the habitability of the planet. But the team found that perchlorate could also be activated under the only effect of the UV. While this compound is abundant on Mars, the planet is also very cold, so we weren't sure if it was possible to activate it under Martian conditions.
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 chose to recreate Mars conditions and soil to see whether Earth friendly bacteria can survive.
One way to turn a perchlorate into an oxidant is to expose it to UV light, and since Mars has a much thinner atmosphere than Earth, there's plenty of this kind of radiation on its surface. Other perchlorates found on Mars had a similar bactericidal effect.
NASA says these microbe-killers or perchlorates were discovered in various locations on Mars. This hypothesis was backed up by the observation that low temperatures, which slow down chemical reactions, extended the lifespan of the bacteria in the perchlorates but still resulted in them dying.
Despite those dreams now seeming farfetched, Ms Wadsworth said there was still a chance for life on the red planet. As we start to look at lower radiation environments on other planets in search of life, it's important we build up our knowledge of such conditions on life as we know it, which will help us understand what such ecosystems might look like.
There still remains some hope for surface microbes.
"With the ExoMars rover, we will drill to retrieve and analyse samples from up to 2m under the surface", he added. Although we have our own problems with perchlorate here on Earth - too much of it can mess with the thyroid gland - the new paper suggests that perchlorate is particularly nasty on Mars.