Atacama Desert Microbes May Hold Clues to Life on Mars

Picture taken at one of the sites inspected in the hyperarid core of the Atacama Desert. Note the Petri plates with different growing media placed on top of the soil surface. (Dr. Armando Azua-Bustos)

(CN) – The winds on Mars could be transporting life via dust, given how microbial life moves across the Atacama Desert in northern Chile.

In a study published Thursday in the journal Scientific Reports, researchers detail the movement of fungi and bacteria across the hyperarid Atacama.

“It’s useful in the terms of that we are sending mission after mission to Mars,” said Armando Azua-Bustos, of the Chile-based AngelicvM Center for Aerospace Research and Development, in an interview.

“We could have inadvertently sent microbial life to Mars on a rover or on a lander that could have been dispersed on the surface of Mars by the winds there,” Azua-Bustos said.

To test their ideas in the Atacama, researchers took samples from spots where virtually no water is available, soil is highly saline, and carbon from once-living sources is nearly impossible to find.

Professor Azua-Bustos and González-Silva wear sterile suites and use collecting materials in order to avoid the contamination of the sites studied in the Coastal Range of Atacama Desert in Chile. (Margarita Azua)

In sample sites on west-east transects in two parts of the desert, the team found 23 bacterial species as well as eight species of fungus. Three species showed up in both transects studied.

One bacterium, Oceanobacillus oncorhynchi, could be traced to an aquatic environment, likely the Pacific Ocean. Another, Bacillus simplex, came from plants.

The plant-based bacterium could be traced to the Coastal Range, which borders the barren desert in the west. The results suggest the existence of a number of “airborne ecosystems.”

“I think the most surprising thing is how life is able to survive some of the most extreme conditions,” Azua-Bustos said.

The Atacama is Earth’s driest desert outside of a polar region. Some team members required medical attention for rehydration.

All had to take care working in the “highest measure of UV radiation anywhere on Earth,” Azua-Bustos said.

Next up for the team: “We are about to describe a new site in which its soils are rich in hematite,” Azua-Bustos said. This “more and more looks like Mars on Earth.”

Rich in iron and related to rust, hematite gives Mars its red coloring.

Azua-Bustos said he’s motivated by the need “to understand the limits of life on Earth and what this can tell us about the possibility of finding life elsewhere in the universe.”

Despite a mean surface temperature of minus 82 Fahrenheit, Mars is considered the most habitable of nearby planets mainly because signs of water appear at times on its surface. Its atmosphere is about 1% as dense as Earth’s, so the winds on Mars, created by changes in soil, behave differently and are not as intense as Earth’s, which happen when air moves due to the sun’s uneven heating of land and water.

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