A unique ecosystem in one of the harshest places in the world has offered a glimpse into the earliest stages of life on Earth and possibly on ancient Mars.
The previously unknown environment in Argentina’s Puna de Atacama, a high plateau desert more than 3,500 meters above sea level, was discovered by Professor Brian Hynek.
The plateau is among the driest on Earth. Rain rarely, if ever, falls and the sunlight is unforgivingly strong – meaning few plants or animals can survive.
However, Professor Hynek from the University of Colorado Boulder found that something has managed to make its home here.
The desert in Argentina is made up of a system of lagoons, in which Prof Hynek found vibrant displays of stromatolites – complex microbial communities that form giant mounds of rock as they grow, similar to how corals build a reef millimeter by millimeter.
According to Prof Hynek’s initial observations, these stromatolites may resemble those that existed during a period in history called the early Archaen, when oxygen was almost non-existent in the atmosphere.
“This lagoon could be one of the best modern examples of the earliest signs of life on Earth,” said Prof Hynek.
“It’s unlike anything I’ve ever seen or, really, like anything any scientist has ever seen. Finding the environment was the biggest eureka moment I’ve ever had in my life. It’s just amazing that you can still find undocumented things like that on our planet.”
Prof Hynek and his colleague Professor Maria Farías, a microbiologist, believe that their findings also offer some insight into what life on ancient Mars may have looked like.
“The fact that the stromatolites formed in this harsh environment suggests that the desert could resemble the conditions on ancient Earth,” Prof Hynek explained. “The waters are salty and acidic and, because of the high elevation, are exposed to severe levels of solar radiation. If life ever evolved on Mars to the level of fossils, it would have been like this. Understanding these modern communities on Earth could inform us about what we should look for as we search for similar features in the Martian rocks.”
Professors Hynek and Farías said they could determine that the stromatolites were ancient rather than modern because of certain characteristics they possessed.
Stromatolites exist on Earth today, including off the coast of the Bahamas, but modern ones tend to be relatively small, whereas ancient ones could stretch to six meters.
The mounds in the Atacama lagoons were sizeable and looked a lot more like some of the Archaean communities than anything alive on Earth today.
Professor Farías explained: “Their rocky layers were constructed mostly from gypsum, a common mineral in many stromatolite fossils but absent in almost all modern examples of stromatolites.
“Biologically, they were made up of an outer layer of photosynthetic microbes called cyanobacteria and a pinkish core rich in archaea—single-celled organisms often found in extreme environments on Earth.”
The researchers hope to return to the Argentinian lagoons soon to confirm their initial results, although the journey will not be easy.
The first time around, they had to drive nine hours down a dirt road, stay in a village of around 35 people who rely on a single spring for water, and hike several miles in the blazing sun.
“In some places, we were sinking up to our knees in salt slush,” Professor Hynek said.
But when he found the network of 12 lagoons – with giant mounds of green growth beneath their crystal clear waters – he knew it had been worth it.
Professors Hynek and Farías will have to act fast if they wish to conduct further experiments however, as a company from outside Argentina has already leased the area to mine for lithium.
Once drilling begins, the Atacama lagoons could be irreversibly transformed.
“This entire, unique ecosystem could be gone in a matter of years,” Professor Hynek said. “We’re hoping that we can protect some of these sites, or at least detail what’s there before it’s gone or disturbed forever.”
Produced in association with SWNS Talker
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