‘Secret’ biosphere discovered beneath the world’s driest desert

Scientists have discovered microbial life 4 meters (13 feet) below the surface of northern Chile’s Atacama Desert, the most “hostile” desert on Earth.

The Atacama Desert is known as the world’s driest and hottest desert, where the sun shines so intensely that life seems impossible.

Scientists have discovered a resilient bacterial community thriving in the extremely dry Yungai Valley. This microbial community is completely isolated from the terrestrial world.

“To our knowledge, this represents the deepest investigation and discovery of Atacama soil microorganisms to date,” the study authors said.

Despite the harsh environment, microorganisms thrive in desert soils rich in salts and sulfates. These conditions provide a unique environment for certain microorganisms to live.

The presence of microorganisms was previously recorded at depths of 80 cm (2.6 ft) in the Atacama Desert, stating that “the first 80 cm of the soil is a potential shelter from harsh UV rays and allows for some water infiltration. It is considered a place where you can find. ” However, the discovered biosphere has recently been “completely isolated from the Earth’s surface.”

To uncover this hidden biosphere, scientists led by Dirk Wagner and his colleagues used samples collected from the subsurface soil of the Yungai Valley, part of the desert, to discover The recovered DNA was extracted.

They found that microbial life extends from 2 meters (6.6 feet) to at least 4 meters (13 feet) below the desert surface.

Types of microorganisms present

The upper 80 cm of the sand deposit was infested with microorganisms of the phylum Firmicutes. At a distance of less than 200 cm, we observed a distinct microbial community dominated by actinobacteria, a diverse group of bacteria found in other extreme environments such as the Arctic, boiling hot springs, and salty oceans.

Digging deeper, the researchers discovered bacteria from the phylum Firmicutes that can tolerate high concentrations of salt and do not require oxygen to survive.

During genetic analysis of the microbial community, some bacteria showed genetic similarity to two specific species, Geodermatophilus pulveris and Modestobacter caceresii. Both types of bacteria belong to the family Actinobacteriaceae.

Scientists suggested that this group of actinobacteria may have colonized soil 19,000 years ago, “before it was buried in marsh sediments.” They hypothesized that this community could extend downward for an infinite distance and represented a previously unknown deep biosphere beneath it. Very dry desert soil.

Scientists hypothesize that this microbial colony may be able to thrive at such extreme depths by obtaining water from the mineral gypsum.

The Atacama Desert is often used as an example for studying extreme conditions on Mars. There, the surface is completely devoid of life, but evidence of microbial life may be hidden beneath.

Scientists say new research could boost efforts to search for life on Mars, as the planet also contains gypsum deposits that could be a source of water for extraterrestrial life. did.

The study was published in the journal PNAS Nexus.

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