Scientists have found out that some of the components found in the Martian soil can destroy whole bacterial cultures within just a few minutes. Researchers have long wondered if microorganisms will be able to survive on the surface of the Red Planet. And the results of the latest laboratory tests show that the fate of any green bacterium on the surface of Mars will be unenviable. Apparently, growing potatoes on Mars will be much more difficult than previously thought.
The problem is perchlorates – chlorine-containing chemical compounds, first discovered on Mars in 2008. These substances are able to keep water on Mars in a liquid state, but actually turn it into an acidic brine. For humans, perchlorates are toxic, but they do not necessarily create the same problems for microbes. And since these compounds allow the water to be in a liquid form, scientists previously believed that their presence on Mars can be useful for life.
However, researchers at the University of Edinburgh say that the impact of strong ultraviolet light on these compounds turns them into a deadly poison for absolutely any life forms.
“Perchlorates remain stable at room temperature, but become a powerful oxidant when activated, for example, by high temperatures,” the researchers report.
One way to convert perchlorate into an acid is to act on it with a powerful source of ultraviolet radiation. Since Mars is much less dense than the terrestrial atmosphere, its surface is exposed to a similar type of radiation every day.
The scientists decided to conduct an experiment. They took a bacterium Bacillus subtilis (Sennaya bacillus) found on the plating of space vehicles (including the ISS) and placed it in conditions artificially recreating the environment on the surface of Mars. Bacteria floated in a solution of magnesium perchlorate of the same concentration as that found on the Red Planet, and then they were subjected to ultraviolet radiation of the same wavelengths that bombard the Martian surface. As a result, no bacteria survived. Death occurred within just 30 seconds.
To test the experiment, the researchers also exposed ultraviolet light to bacteria that were not placed in the perchlorate medium. But even in this case the entire colony was destroyed within just 1 minute.
Of course, the surface of Mars is not so wet as the bottom of the Petri dish. Therefore, scientists decided to conduct a similar experiment, placing the bacterium in a drier condition – silicon dioxide. Such a medium slightly simplified the existence of bacteria Bacillus subtilis, but in the end most of them still perished. From this we can conclude that if there is life on Mars, then, most likely, it hides deep beneath the surface of the planet, where the concentration of perchlorates is much lower.
“Despite earlier suspicions of the presence of toxic effects caused by acids present on the Martian surface, our observations show that the environment on the surface of modern Mars is even more hostile to living cells and is a rattling cocktail of acids, iron oxide, perchlorate and Ultraviolet radiation, “- say scientists.
If salt streams descending from the Martian rocks really represent concentrated flows of perchlorates, then such a medium is clearly unsuitable for sustaining life. And since perchlorates are present almost on the entire surface of the Martian soil, then, based on the conclusions of the team of researchers, it is possible to note with sadness that most of the surface of the planet is uninhabited.
But in this there is a share of positive news. If the Martian surface is capable of killing all terrestrial microbes on contact, then for the planet itself it will represent an excellent protective tool – there is less chance that in the framework of future missions we will be able to bring our earth microbes there.
Scientists, in turn, are going to continue their research and find out exactly how such a deadly cocktail on the Martian surface kills living cells.