Imagine one of the driest places on Earth, where more complex life forms are barely present, yet a rich microbial world bustles just beneath the surface. This is the Atacama Desert in Chile, a harsh landscape that has just given up a stunning secret.
Researchers now report the discovery of a buried biosphere, pulsing with microbial life, as much as 13 feet beneath the Atacama’s arid soil. Most of the colonization is done by Actinobacteria, resilient beyond expectation in an otherwise quite unsupportive environment for life. Previous studies found microbial life down about 2.6 feet; this new discovery takes things considerably deeper.
Now, in a landmark study, scientists have demonstrated that even the most inhospitable regions of the Atacama are home to microbial life. The researchers focused on the Yungay Valley, A very desolate part of the Atacama for that report, published Thursday in Science. The researchers dug more than 4 meters deep; with the new, innovative DNA extraction methods that ensure one actually is studying living organisms washing out loose DNA, then extracting DNA from intact cells allowed for an accurate picture of the microbial communities within the soil.
Inhabiting the top 0.8 to 2 inches, they found Actinobacteria. A group able to put up with the tightest conditions from the Arctic to boiling hot springs. The deeper they went, the more microbial life dropped from 2.6 to 6.6 feet, where there were concentrations of salt so high that even the most vigorous bacteria couldn’t survive. Beyond this “dead zone,” an entirely different bacterial community began to appear:.
Firmicutes dominated in such deeper layers, capable of surviving with no oxygen and resistant to the highest levels of salt. The discovery may be viewed as touching very deep roots in the adaptability of microbial life under extreme conditions. Actually, again, the study gives much for existence under similar circumstances here on Earth and, most importantly, in the search for extraterrestrial life, mainly on Mars.
Some geological features of Mars and Chile’s Atacama Desert are alike, including gypsum deposits. In one very important way, the same can become a viable source of water for microbes living on Mars, where in the soil one also finds vast deposits of gypsum. This opens up the possibly exciting possibility of microbial life beneath the Martian surface that uses similar survival strategies.
The researchers propose that the deep microbial community of Atacama was colonized in the soil some 19 000 years ago and has since been buried by the subsequent deposition of more recent soils. This buried biosphere—the upper tip explored in this work at only 4.5 meters—could run very much deeper. Just the upper tip, then, of a very ancient, vast, hidden ecosystem.
This finding has huge implications, livemint comments. How these microbes in such extreme conditions keep themselves alive is of critical understanding to the boundaries of life on Earth that will help guide future explorations of other planets and moons within our Solar System. As the authors state at the conclusion of their research, it follows that investigation of gypsum-related subsurface environments in the Atacama Desert is of peculiar interest in astrobiology, since on Mars, gypsum deposits. Not only testify about ancient liquid water but also may act as a natural IV system that passively delivers water to currently existing microbial life.
Next time the vast majority of us read or hear something about the desolate, sterile Atacama Desert, so devoid of life, remember the hidden world right underneath its surface—a colorful display in microbial life and dumbfounding expression of how resilient life can be and what it has to tell us about possible life off this planet.
