Mars soil may be toxic to alien life: Study

As per a research conducted by scientists at the University of Edinburgh in the United Kingdom, surface of Mars has chemical compounds called perchlorates that can wipe out living organisms.

The discovery has major implications for hunt for alien life on the red planet as it means any evidence is likely to be buried deep underground.

The study was published in the journal Scientific.

Key highlights

• The research was driven by the discovery of powerful oxidants known as perchlorates in the Martian soil a few years back.

• Hints of perchlorates first showed up in tests performed by NASA’S Viking lander missions 40 years ago. However, the fact was recently confirmed by NASA’s Phoenix lander and Mars rover, Curiosity.

• In 2015, the Mars Reconnaissance Orbiter spotted signs of perchlorates. Many scientists suspected that perchlorates would be toxic for microbial Martians, however, alien bacteria might find a way to use the chemicals as an energy source.

• The researchers looked at what happened to Bacillus subtilis, a common soil bacterium and regular Earthly contaminant found on space probes, when it was mixed with magnesium perchlorate and blasted with ultraviolet rays similar to those witnessed on Mars. It was found that the bugs were wiped out twice as fast when perchlorate was present.

• Further tests found that the UV rays broke down the perchlorate into other chemicals, namely hypochlorite and chlorite.

• In addition, the researchers also followed-up with another round of experiments that looked at the toxic effects of iron oxides and hydrogen peroxide, which are also found in Martian soil.

• As per further tests, when the bacteria were hit with UV rays in the presence of perchlorates, iron oxide and peroxide, the bugs were killed 11 times faster than with perchlorates alone.