The Atacama Desert, the driest together with oldest desert on Earth, located inwards northern Chile, hides a hyper-arid pith inwards which no pelting has been recorded during the past times 500 years. But this province of affairs has changed inwards the final 3 years: for the start time, rainfall has been documented inwards the hyper-arid pith of the Atacama and, reverse to what was expected, the H2O render has caused a peachy destruction amidst local life. This is the principal determination of an international study, published inwards Scientific Reports together with entitled "Unprecedented rains decimate surface microbial communities inwards the hyperarid pith of the Atacama Desert", together with directed past times researchers from the Center for Astrobiology (CAB), a mixed middle of the Spain's Higher Council for Scientific Research (CSIC) together with the National Institute of Aerospace Technology (INTA). These recent rains are attributed to changing climate over the Pacific Ocean.
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| Atacama Desert [Credit: Carlos Gonzalez Silva] |
"Our travel shows that high rainfall has caused the massive extinction of most indigenous microbial species. The extinction hit reaches 85%, equally a effect of the osmotic stress that has caused the abrupt abundance of water: the autochthonous microorganisms, which were perfectly adapted to thrive nether atmospheric condition of extreme dryness together with had strategies optimized for the extraction of the scarce humidity of their environment, convey been unable to accommodate to the novel atmospheric condition of abrupt flooding together with convey died from excess water", adds Fairén.
From Atacama to Mars
This study represents a peachy advance to sympathise the microbiology of extremely arid environments. It too presents a novel image to decode the evolutionary path of a hypothetical early on microbiota of Mars, since Mars is a hyper-arid planet that experienced catastrophic floods inwards ancient times.
"Mars had a start period, the Noachian (between 4.5 together with 3.5 billion years ago), inwards which at that topographic point was a lot of H2O on its surface," says Fairén. "We know this from the enormous total of hydrogeological bear witness however introduce inwards the Martian surface, inwards the shape of ubiquitous hydrated minerals, traces of dried rivers together with lakes, deltas, together with peradventure a hemispheric body of body of water inwards the northern plains," explains Fairén.
Mars eventually lost its atmosphere together with its hydrosphere, together with became the dry out together with arid public nosotros know today. "But at times during the Hesperian menstruum (from 3.5 to 3 billion years ago), large volumes of H2O carved its surface inwards the shape of outpouring channels, the largest channels inwards the Solar System. If at that topographic point were however microbial communities withstanding the procedure of extreme drying, they would convey been subjected to processes of osmotic stress like to those nosotros convey studied inwards Atacama", Fairén details.
"Therefore, our Atacama study suggests that the recurrence of liquid H2O on Mars could convey contributed to the disappearance of Martian life, if it always existed, instead of representing an chance for resilient microbiota to bloom again", adds Fairén.
In addition, this novel study notes that large deposits of nitrates at the Atacama Desert offering bear witness of long periods of extreme dryness inwards the past. The nitrates were concentrated at valley bottoms together with quondam lakes past times sporadic rains almost thirteen 1000000 years ago, together with tin live on nutrient for microbes. The Atacama nitrates may stand upwards for a convincing analog to the nitrate deposits lately discovered on Mars past times the rover Curiosity (and reported inwards a 2015 study entitled "Evidence for indigenous martian nitrogen inwards venture samples from the Curiosity rover investigations at Gale crater", inwards the Proceedings of the National Academy of Sciences). Earlier this year, Fairén together with colleagues discovered that short-term wetter environments inwards early on Mars, occurring sporadically inwards a mostly hyperdry early on planet, explains the observed martian mineralogy.
"These long periods of dryness, followed past times short-term wetter conditions, may too live on inwards the root of the nitrate deposits on Mars", concludes Fairén.
Source: Castilian National Research Council [November 14, 2018]
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