In a big blow to the hopes of finding alien life on Mars, a study has revealed that the surface of the red planet has a toxic mix of chemicals that can wipe out living organisms.
The behaviour of the chemical compounds called perchlorates that are present in the Martian soil was studied by the researchers at the University of Edinburgh in the UK.
The study found that the chemicals can kill bacteria commonly carried by spacecraft when exposed to ultraviolet (UV) light in environmental conditions mimicking those on Mars.
“Our findings have important implications for the possible contamination of Mars with bacteria and other materials from space missions,” said Jennifer Wadsworth from Edinburgh’s School of Physics and Astronomy.
“This should be taken into account in designing missions to Mars,” said Wadsworth.
Two other types of chemicals found on Mars’ surface, iron oxides and hydrogen peroxide, can compound the effect of perchlorates, the study noted.
The combination of all three in experiments led to over 10-fold rise in death of bacterial cells compared with perchlorates alone. Since their discovery there several years ago, scientists have speculated on the influence that perchlorates may have on the habitability of the planet.
Researchers probed the potential reactivity of perchlorates and their effect on Bacillus subtilis, a bacterium found on spacecraft and common in soils and rocks.
When magnesium perchlorate was exposed to UV radiation similar to that on Mars, it became capable of killing bacteria much more effectively than UV light alone, the experiment found.
Cells of B subtilis quickly died at concentrations of perchlorate similar to those found on the Martian surface. The latest study suggests that it may be highly damaging to living cells, although the Martian surface has been suspected for some time to have toxic effects.
This is owing to a toxic mix of oxidants, iron oxides, perchlorates and UV energy, researchers said. The study was published in the journal Scientific Reports.
(With inputs from PTI)