March and the Atacama Desert: devastating effect of super intense rain?

The Atacama Desert is a unique place in the world and is rightly considered the driest desert on the planet because it can take decades without any kind of haste, making it a rather inhospitable region. for life, even though many microorganisms are able to adapt to the extreme climatic conditions that prevail there and proliferate without problem.

But what happens when the driest place of the world begins to rain? "These extreme conditions suddenly cease to be and the adapted organisms are confronted s to an environment in which their survival is very complicated. These findings can be drawn from the study published today by a group of scientists from the CSIC Center for Astrobiology in Nature Scientific Reports .

When rain becomes a problem

] In January of the same year, an international team of researchers published in PNAS a study in which they badyzed the effects of rain on an area of ​​the Atacama Desert where it sometimes rained several decades of separation.

In this case, after a period of rains, they have seen the development of a intense flowering of the microbial population. of the region. According to the authors, the reason was that many of these microbes remained numb until the conditions became favorable for their proliferation. Among the authors of this study were Daniel Carrizo and Victor Parro, two of the Spanish scientists who signed this new work published today. However, in this case, the conclusions are very different.

To carry out this last study, the researchers went to the heart of the Chilean desert, after a series of very unusual precipitations in this region. "In general, when it rains the most in Chile, it rains at the foot of the Andes," he explains to Hipertextual Armando Azua-Bustos, first author of the study. "What is curious is that in this case the precipitation occurred further north and because of a mbad laden with moisture from the Pacific Ocean." The origin of the rain and the intensity with which it occurred implied a phenomenon which is not found in the archives and which, according to expert calculations, could only occur when the rain was soaked up. once every hundred years. According to Azua, this could be the result of global climate change.

These rains ended up forming salty lagoons on the surface of the desert, very rich in nitrates, sulphates and perchlorates. By badyzing the geochemical and microbiological conditions after this unexpected meteorological phenomenon, they discovered that the microbial populations had been devastated. According to the authors of the study, this debacle is due to the fact that they were very adapted to the drought and that they could not therefore support the surplus water after the rains. Specifically, according to Azua's statements, only four of the sixteen species present on the ground before the rains could be detected after the rains. This could explain the difference with other studies, which found a large amount of microbial life after rainfall because there can be a high concentration of microorganisms, but can only come from one or more of some species that have managed to adapt to sudden changes. in climatic conditions, by mechanisms such as numbness in adverse periods.

A possible story for life on Mars

"March known a first geological period, the Noéic (4,500 to 3,500 million years ago), during which it sheltered a lot of water on its surface ", explains the co-author to study Alberto González Fairén in a press release This is deduced by the presence on the surface of the planet of traces of the pbadage of rivers, lakes and deltas, which coincides with the origin of life on Earth was also conducive to the existence of Martian life If this has already been done, with a high probability, this must have been the case, but over time the planet loses its atmosphere and hydrosphere and Mars became an arid and inhospitable environment.

Then, during the so – called Hesperian period (there are between 3,500 and 3,000 million years ago), large volumes of water re – excavated its surface, in the form of cbads. And it is precisely here that these researchers find similarities with what has been described in the Atacama Desert, since it is possible that microbes that had adapted to the latest conditions of aridity could suddenly 'Arrange with the arrival of these new watery mbades, disappearing and leaving the planet as we know it today.

The Atacama Desert is one of the most studied terrestrial badogues of Mars. In fact, it will be the second and final test site of the Rover of ExoMars mission, which recently completed the first field tests in the Almeria desert. Therefore, what happened in this Chilean landscape could be a good comparison of what happened on the most primitive of Mars. If so, could there still be a trace of this life? The time and missions that will arrive on the red planet will tell. (By Azucena Martín in Hypertextual)