'Special gold mine' in the harsh part of the Earth: More precious than lithium, the scientific world is constantly hunting!

Amazing life in the arid core of the Atacama

It's easy to imagine why the 'Father of Evolution' Charles Darwin, looking across a clearing 187 years ago, declared the region (the Atacama desert in northern Chile) a place where 'nothing is possible' exist'.

Indeed, although scattered waters support some plant and animal life, for over a century most scientists have accepted Charles Darwin's conclusion that here - in the arid of the Atacama Desert, known as the super-arid core, even the most resilient life forms can't last long!

But Charles Darwin was probably wrong and that's why Gómez-Silva is here.

Waking up before dawn to beat the hottest heat of the day, then driving south along Chile's Coast Mountains, the team turned inland toward the arid core of the Atacama Desert. Here, Gómez-Silva, a desert microbiologist from the University of Antofagasta (Chile), will search for a microscopic fungus that he hopes to be able to isolate and grow in his laboratory. They are something that, to a scientist like him, is more precious and rarer than lithium or any other metal.

Scientist Gómez-Silva (wearing a hat) is collecting rock salt in the arid core of the desert.

Despite knowing that he is in the driest place on Earth, Gómez-Silva believes there is water here, hidden in the surrounding salt rocks. Just as the salt shaker in the kitchen will absorb water in wet weather, the rock salt at Atacama absorbs the small amount of moisture that blows in as ocean fog at night. And that's where microorganisms find refuge.

When moisture and sunlight coexist, these microorganisms begin to photosynthesize and grow their communities.

Gómez-Silva is part of a team of scientists determined to find the microorganisms that live here - in the world's oldest desert, a place arid since the late Jurassic dinosaurs roamed the land. Earth about 150 million years ago.

Anything trying to survive here faces a terrible set of challenges - besides the lack of water, of course: intense solar radiation; High concentration of harmful chemicals; And the scarcity of vital nutrients for life.

Yet despite those challenges, the unusual and the small still thrive, and researchers like Gómez-Silva say scientists have a lot to learn from them.

'Finding and demonstrating the persistence of these tiny creatures is involved in changing the world's view of the Atacama Desert, an area historically prized for mineral extraction. more precious than ever. We believe that the Atacama should be appreciated as a place to describe previously unknown life forms on Earth, thereby helping scientists develop new tools in biotechnology, to answer the question the origin of life and guide us on how to search for life on other planets'.

Atacama - A place to challenge planetary life

Atacama stretches about 966km along the coast of South America, and lies to the east near the Altiplano volcano of the Andes, to the west on the Pacific coast of Chile. About the size of Cuba, this Atacama Desert is the most life-challenging place on Earth.

Not only is it one of the highest deserts in the world, the Atacama is also the driest place on the planet. Many parts of this desert receive only a few millimeters of rain per year, if at all. The Arica city of the Atacama desert, just below the border of Peru, holds the record for the longest dry spell in the world - researchers believe not a single drop of rain fell in the region in more than 14 years in the early days of the year. the year 1900.

The Atacama Desert is known as "Mars on Earth". .

Without water, few species can survive: Cells shrink, proteins break down, and cellular components can't move.

The high-altitude atmosphere of the desert cannot block the harmful rays of the Sun. And the lack of running water leaves precious metals to miners, but means limited distribution of nutrients through the ecosystem, as well as dilution of toxic compounds.

Where water bodies exist in the desert – often in the form of seasonal basins provided by underground rivers – they often have high concentrations of salts, metals and elements, including arsenic, that are toxic to humans. many cells.

Seeing such conditions during the Atacama expedition in the 1850s at the behest of the Chilean government, even the German-Chilean naturalist Rodulfo Philippi exclaimed: The most valuable thing about the Atacama lies in its mining!

Mining is more than enough to make the Atacama desirable for Chile. It has huge reserves of potassium nitrate (salt pepper, KNO3) - a source of nitrate used in fertilizers and explosives, and it was dubbed 'white gold' due to great global demand in the 19th century. .

Besides Potassium nitrate, mining activities are still very active in Atacama. Today, Chile is the world's No. 1 copper exporter; ranked in the top for lithium; It is also a major supplier of silver and iron, and other valuable metals and minerals.

Mining has a long history in the Atacama and today the desert is the main source of lithium, among other metals. This 2018 aerial shot shows lithium mining in the desert's salt basin.

Mining has made its own mark on the Atacama Desert. Seen from space, Salar de Atacama, a salt flat nearly four times the size of New York City (USA), shows pale lithium deposits. Gold and copper deposits appear as dugouts, like scars on the surface of arid desert.

On the ground, too, it is not difficult to find relics of the area's mining history. Near where Gómez-Silver collected rock salt in the Yungay region is a cemetery with graves dating from the 1800s to the mid-20th century. They were workers of the abandoned salt mines and their families.

Scientist's "Special Gold Mine"

In 1994, the University of Antofagasta (Chile) set up a small research station in Yungay with the support of NASA, where astronomers were interested in the harsh Mars-like conditions of the Atacama Desert.

NASA began studying whether life could exist in the soil and dry rock here in the mid-1960s. But it wasn't until 2003, when a popular paper detailed why the Atacama Desert was a Mars-like place, that microbial research in the area really began to succeed. Investigations into the Atacama have steadily increased since scientists from fields including ecology, genetics, and microbiology have joined efforts.

'However, scientists are only getting close to the surface of the Atacama. Because most of the life here is still unknown," said Cristina Dorador, microbiologist Atacama at the University of Antofagasta (Chile).

Cristina Dorador studies the microbial mats that thrive beneath the crust of the Atacama salt deposits. There are millions of microorganisms of many different types. Species cluster together in clear, colorful layers.

Scientists believe these are the earliest ecosystems to form on Earth. As they grow, some microbial mats form layered deposits that can be left behind as quartz fossils, known as stromatolites. The oldest of these stromatolites dates back to 3.7 billion years, when Earth's atmosphere was devoid of oxygen!

Tourists on a salt flat in the Atacama Desert.

Innovative survival strategies abound at the Atacama, which appeals to scientists interested in understanding how life may have changed over time.

In 2010, a research team in Chile reported the discovery of a new species of dew-dwelling bacteria clinging to spider webs in a coastal Atacama cave, well-positioned to swallow mist in the morning. morning. Dunaliella, a green unicellular algae, is the first in its genus to be found living outside of water, and its discoverers suggest that its adaptations may have been similar to those of other species. primitive plants created when they first arrived on land.

Other bacteria play an active role in finding water. In 2020, a team of scientists from the US described a bacterium that lives in gypsum rock secreting a substance to dissolve the minerals around it, releasing individual water molecules that have condensed within. rock.

"They're almost like miners. digging for water," said David Kisailus, a chemical and environmental engineer at the University of California (USA).

Examples like these are just a few of the many examples of how the microorganisms in the Atacama teach us about survival in the harsh environment on Earth. And such lessons could help us spot clues in our search for life on other alien worlds, or help us adapt to environmental changes that come our way.

Michael Goodfellow, Emeritus Professor of Microbial Systems at the University of Newcastle, UK, says the arguments for conservation and microbial discovery are beyond scientific curiosity.

Michael Goodfellow has spent most of his career searching for new species of bacteria in extreme environments such as the Atacama, Antarctica, and deep trenches on the ocean floor in hopes of identifying new molecules for use in antibiotic resistance. born.

Such biosurvey in extreme environments should be seen as an important strategy to confront the global crisis of antibiotic resistance, which kills at least 700,000 people a year worldwide, he argues. bridge.

On their first trips to the Atacama's super-arid core, Michael Goodfellow and his colleagues didn't really expect to find much. However, nature always surprises people.

To their surprise, the scientists were able to isolate a small number of soil bacteria from the group of Actinomycetes, a globally common soil bacterium that has long been an important focus of resistance research born. Since then, research on these bacteria has produced more than 40 new molecules, some of which inhibit common pathogenic bacteria in laboratory studies.

Michael Seeger, a biochemist at the Federico Santa Maria Technical University in Chile, says biological research in deserts like the Atacama also has technological applications.

A major example is microorganisms that account for about 10% of Chile's copper production. Copper is commonly found in a mixture of metals, and microorganisms can help extract it by eating away at other materials in the ore.

By keeping these microorganisms out of contact with mining piles or ore mixes where only small concentrations of copper exist, copper producers can ensure less copper is wasted. at their mining sites.

"Such metal-crushing bacteria must be able to handle high concentrations of acid because they produce acid as a waste product," says Michael Seeger. To thrive in highly acidic conditions, acidophilic species These must have special adaptive abilities such as specialized cell membranes to block acidic particles, quickly remove those harmful elements from the cell, and enzymes capable of rapidly repairing proteins and DNA".

The Atacama Desert is likely filled with exotic species like these, with specialized abilities that make them useful for industry and other practical purposes.

"Arsenic bacteria could be useful for cleaning up contaminated water sources, and genes borrowed from salt- or drought-tolerant bacteria could be transferred into soil bacteria to promote agriculture," says Michael Seeger. in a country facing increasing desertification".

Proteins that perform well in extreme conditions can also have important medical applications. For example, a Covid PCR test would not be possible without a bacterial enzyme that can produce DNA strands in extreme temperatures and was originally taken from a Yellowstone hot spring in the US.

Biologists hope that studying enzymes with similar tolerance to extreme conditions from desert microorganisms could lead to additional biotechnological breakthroughs in the future.

The Atacama, while harsh in various ways, is still capable of harboring more capable microorganisms than we've known, and so it's important for scientists to find it. what is there!