The first rains after centuries in the Atacama Desert caused death, not life



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The researchers found something very strange in the driest non-polar region of the globe, the Atacama Desert. According to their new research, a rain of 2015 has wiped out living microbes and completely transformed the region.

According to the co-author of this study, published in the journal Scientific Reports, Alberto Fairen of Cornell University said in a statement: "When the rains arrived at Atacama, we were hoping for flowers and majestic deserts. "But he did exactly the opposite and we found that the rain in the hyper-arid nucleus of the Atacama Desert caused the massive extinction of most of the microbial species native to the region."

He added that "the extremely dry soils before the rains were inhabited by up to 16 different ancient microbial species" and that after the rain, "there were only two to four microbial species found in the lagoons. The extinction event was huge. "

The research team said that a sudden and massive rainfall in hyper-arid populated areas of several million years ago actually makes most microbial species on the surface because these are extremely suitable for surviving in inhospitable conditions. According to the team, the sudden entry of excess water disrupts the normal functioning of microbes through a process called "osmotic shock".

The first rain for centuries on the Atacama hyper-arid core has been caused by climate change in the Pacific. After 2015, the same phenomenon occurred on June 7, 2017.

However, this discovery provided a broader avenue for exploring and understanding than the way microbial life evolved on Mars, with many astrobiologists claiming similarities between the Atacama and Martian surfaces.

A little earlier, scientists said that the red planet had a complex history of global climate change and that there are nearly 4.5 billion to 3.5 billion years ago it could have – be subjected to large amounts of water on its surface. But year after year, because of the change of atmosphere, Mars turned into a desert-like planet. Even many times, 3.5 billion years ago, the transition was interrupted due to huge water dumps that flooded areas on the surface.

The authors of this new study wrote that as a result of such events on the red planet, the "hypothetical local ecosystems existing in some places on Mars and adapted to the increasing drought of the surface and subsoil of the planet after 3.5 billion years ago – were exposed episodically to osmotic stresses even stronger than those described here for Atacama's "microorganisms," and "the recurrence of liquid water to the surface after early times may have contributed to decimating local or regional ecosystems, instead of being an opportunity for life to flourish again in the flooded areas. "

Referring to the samples collected by the Viking space probes, the team of researchers said: "The negative results obtained with the life detection instruments onboard the 1976 Viking landing gear could find the simplest explanation in the fact that in both experiments, with various aqueous solutions. "

"The potential Martian cells would not have been exposed to such high water activity values ​​for at least millions of years. Therefore, their sampling and inclusion in the Viking experiments would have caused their osmotic burst, followed by the subsequent destruction of the organic molecules. , They added.

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