Clues to Martian Life Found in Chilean Desert

A trial NASA rover mission in the Mars-like Atacama Desert of Chile. (Prof Stephen B. Pointing)

(CN) – Ahead of a NASA 2020 mission to Mars, researchers have taken to a desert on Earth where they are searching and digging for microbial life in an extremely dry desert as devoid of life as the surface of the red planet.

To get in a good practice run, scientists searched for signs of life in the arid Atacama Desert in Chile, which bears a resemblance to the surface of Mars and, according to a new study published in the scientific journal Frontiers in Microbiology on Thursday, they struck gold.

Understanding how microbial life can move and thrive in sediment rock can provide important clues to how scientists can search for life on Mars.

Researchers found a salt-resistant bacterium that thrived in subterranean soil with little access to water and scarce nutrients.

Funded by NASA and designed by Carnegie-Mellon’s Robotics Institute, researchers let loose a rover-mounted robotic drill and sampling device in the Atacama Desert, where it sought soil samples about 2.6 feet below the surface. The rover traveled over stony desert pavement and a dry lake in the desert as it collected 32 samples.

Professor Stephen Pointing with the Yale-NUS College in Singapore led the microbial research and said the strange organisms found in their study are different from what is typically found on the surface of deserts.

“The core of the Atacama Desert in Chile is extremely dry, experiencing decades without rainfall. It has high surface UV radiation exposure and is comprised of very salty soil. It’s the closest match we have on Earth to Mars, which makes it good for testing simulated missions to this planet,” Pointing said.

Scientists compared the soil samples the rover picked up to samples lifted from the ground by hand and found through DNA sequencing the samples were similar, meaning the technique was successful.

Co-authors Nathalie Cabrol and Kim Warren-Rhodes of The SETI Institute said the results of the study show microbial life on Earth are found in patches when in extreme habitats and that could hint at present or past life on other planets in similar situations.

Astrogeologist James Rice, who was not involved with the new study, but who has field experience working in Moon and Mars analog environments, said the Atacama Desert has many similarities to the red planet but is no replacement for the real deal.

“The Atacama is very harsh and unforgiving, but Mars is a lot worst. The Mars surface is bombarded with radiation and the overnight temperatures drop to about 100 below zero, Fahrenheit,” Rice told Courthouse News Service.

The Atacama does share certain chemical compounds with Mars, like perchlorates which are found in sodium nitrate deposits. Unlike Mars, however, certain regions of the Atacama Desert receive moisture from marine fog.

Rice said Earth’s Antarctic polar deserts have more similarities to the Mars surface, but there is no ideal stand-in. Rice worked as a geology team leader with the NASA Mars Exploration Rover Project, including Spirit and Opportunity and said for years scientists have wanted to look for underground habitats on Mars.  

Starting in 2020, NASA and the European Space Agency will send missions to the red planet where rovers will begin to drill below the Mars surface and collect samples that could one day be recovered and returned to Earth.

Rice said the study in the Atacama Desert expands niches where life could be found on Mars, but also serves another purpose.

“These calibrate us and make us aware of the different environments here and they also make us aware of life on Earth,” Rice said. “It’s durable. It’s hard to get rid of it. The fact that we’re seeing microbial life in all these harsh environments on Earth just shows how robust it is.”

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