Some exoplanets seem inhospitable. Too hot. Too dry to support life. However, the discovery by researchers in the Atacama Desert could lead us to reconsider our view on the matter.
In northern Chile, the Atacama Desert is the driest in the world. Life does not thrive there. At least, not advanced life forms. Because for some years now, researchers have known that in the soil of this remarkable desert, there are some equally remarkable bacteria. Indeed, the top meter of soil could provide shelter from the sun’s ultraviolet rays, and microorganisms could find some water there.
Bacteria Survive in the Desert Subsoil
But researchers from the German Research Centre for Geosciences in Potsdam, Germany, today report in the journal PNAS Nexus how they dug over four meters deep on the Yungay valley side to collect samples. As a result, in the first 80 centimeters, scientists confirm that life is quite abundant. They mainly found Bacillota-type bacteria there.
And then, nothing more. Probably because the soil’s salinity becomes extreme in those areas. However, beyond two meters deep and up to over four meters, researchers came across old fluvial deposits hiding mainly Actinobacteria. Similar to those already found in the Arctic or near hydrothermal vents or even in salty seas. According to them, these bacteria could have colonized the soil about 19,000 years ago before being buried under the sand. Their water supply could come from gypsum.
From the Atacama Desert to Mars… and Beyond?
The surprise is significant for scientists. This deep biosphere was completely unknown to them until now. And the discovery encourages them to rethink how they imagined desert soils. Including those on planets other than Earth. Planets outside our Solar System. Or even Mars. Because astronomers know that the Red Planet hides gypsum deposits that could therefore serve as a water source for extraterrestrial life forms.