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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 hoped for majestic flowers and deserts to wake up" but we have found exactly that the rain in the hyper-arid Atacama desert nucleus has caused the massive extinction of most native microbial species in the region. "
He added that "the extremely dry soils before the rains were inhabited by 16 different ancient microbial species" and that after the rains "there were more than two to four microbial species found in the lagoons. "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 influx of excess water disrupts the normal functioning of microbes through a process called "osmotic shock".
The first rain for centuries on the hyperarid core of Atacama was caused by the changing climate of the Pacific and, 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 at certain locations on Mars, and adapted to the increasing drought of the surface and subsoil of March after 3.5 billion years – were later exposed episodically to osmotic stresses even stronger than those described here for Atacama's "microorganisms," and "the recurrence of the disease." Liquid water on the surface of Mars after the first time may have contributed to decimating local or regional ecosystems, instead of being an opportunity for life to flourish again in 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 aboard the 1976 Viking lander may find the simplest explanation in the fact that in both experiments samples were incubated with various aqueous solutions ".
"All 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 Viking's experiments would have caused their osmotic burst, then the subsequent destruction of organic molecules. ", they added.
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