Desert Atacama, in Chile, hides in its center the drier place on Earth. For the first time since there have been records, it has rained in Atacama's hyper-hearted heart over the past three years, and ephemeral lagoons have formed that have changed the ecological balance of the area. The study of new Atacama vaults allows us to better understand Mars's astrobial evolution.
The Atacama desert, located between the mountains of the Andes and the Pacific Ocean, in northern Chile, is the smallest and oldest wilderness on Earth. However, rain is not unusual in Atacama, because geographically the wilderness includes growing areas and pastures, and coastal areas, which create news of flowers covering areas of Atacama. But Atacama's deserts have a hyper-fat heart that has been at least 500 years since any rain was recorded. The soils of this extremely dry desert center are very saline, and they are rich in nitrates, sulfades and quadrils. And while life is scarce here, it has succeeded in thriving. Its inhabitants are micro-organisms that can tolerate the high levels of drainage and radiation that have characterized the Atacama desert during the last 15 million years.
In the triennium 2015-2017, and for the first time since we had rain records in the area, it has rained significantly in the hypertensive heart of Atacama. As a result, a set of hypersaline lagoons has been established which has lasted for several months for the first time in the area. In a study published today, a group of Spanish researchers have co-ordinated the Astrobiology Center, the CSIC and INTA mixed center in Madrid, we describe our research on the geochemistry and microbiology of the lagoons.
Our group has found that, contrary to what could be expected intuitively, the contribution of water has not meant flowering life in Atacama. In the opposite case, inflammation has caused huge damage to the microbial species that lived in these areas before the levels. The disappearance range reaches 85%, due to the osmotic stress that has caused a sudden abundance of water: the unusual, perfectly adapted microorganisms to live under conditions Extreme drought and making better for the poor moisture extraction of their environment, have been able to adapt to new conditions of sudden flooding and die from excessive water.
Our study of the impact of the formation of a lagoon in the hypertensive heart of Atacama's desert, probably one more result of the global climate change that Earth suffers, also attempts to establish a match what happened on Mars at the time its global climate change lets it out without fluid water, and helps to explain the destiny possible destiny of the Martial biosphere. Mars had a first geological phase, the Noeico (between 4.5 and 3.5 billion years ago), where it was home to a lot of water on its face; We know how much hydrogeolecular evidence is stored, in the form of hydrated mineral surfaces, the remains of rivers, lakes, deltas and perhaps a hemisphere ocean in the northern plains. If life had ever risen on the Mars, it had to be during this first period, which fits with the moment of the origin of life on Earth. Later, Mars lost its atmosphere and hydrosphere, and this is the dry world and land that we know today. But at times during the Hesperian period (between 3.5 and 3 billion years ago), a large amount of water excavated its surface in the form of overflow channels, the largest in the Solar System. If the microbial communities were still resistant to the extreme drying process, they would have been subject to osmotic stress processes similar to those described in Atacama. Therefore, the Atacama study helps us to propose that the recycling of liquid water on Mars could have contributed to the disappearance of Martian's life, if it had never existed, rather than representing an opportunity to grow resilient microbiota.
Similarly, our work provides a coherent explanation of the negative consequences of the Viking editors on the surface of Mars in the 70s of the last century, the only time we have tried life on another planet so far . The Scandinavian experiments were done by stirring samples from the Martian surface in aqueous solutions, in order to try and provide a favorable environment for potential Martian microorganisms to accelerate and grow their metabolism. However, our work suggests that any type of living that could survive even today on Mars would be perfectly adapted to the extreme drought of Martian surface, and thus would have died immediately by a osmotic shock in the Viking instruments. Future experiments looking for life on the Mars should take into account the devastating effects that the first rainfall in centuries has produced on the microbial communities that live in the hyper-hearted heart of the Desert Atacama.