Bacteria could survive underground on Mars for hundreds of millions of years, new study finds

Bacteria could survive underground on Mars for hundreds of millions of years, new written report finds



D. radiodurans (affectionately known as “Conan the Bacterium”) is particularly well-suited to surviving Mars’ harsh environment.
(Image credit: Michael Daly/USU)

As Elton John in one case sang, “Mars ain’t the kind of place to raise your kids; in fact, it’s cold as hell.” But new inquiry suggests that Martian chill could let bacteria to survive for up to 280 million years below the planet’due south surface.

The finding raises hopes that traces of ancient life — or even viable organisms in suspended blitheness — could be found on the Red Planet someday.

In the study, scientists establish that an Earth bacterium,
Deinococcus radiodurans,
is so resistant to radiation that it tin handle the equivalent of 280 meg years of the radiation present 33 feet (10 meters) below the Martian surface. The plucky little microorganism, which has been establish thriving in nuclear reactors on Globe, could even terminal 1.5 million years on the Martian surface, which is constantly bombarded with cosmic and solar radiation.

Related:

Could life on Mars be lurking deep underground?

The key to this survival is Mars’ dry, cold environment. When desiccated and frozen to minus 110.2 degrees Fahrenheit (minus 79 degrees Celsius) — the temperature of dry ice and the college-latitude regions of
Mars

D. radiodurans
“get phenomenally, astronomically radiation-resistant,” said report senior author
Michael Daly, a geneticist and radiation biology skillful at Uniformed Services University in Maryland.

Resisting radiations

D. radiodurans
has long been known to exist a champ at resisting radiation. Information technology’s plant in the human gut and in many other places on Earth, and has even
survived for years in the vacuum of space. The new research, yet, is the offset attempt to test the bacterium’southward upper limit of radiations resistance when it’s in a desiccated country. Previously, scientists had constitute that the bacterium can withstand 25,000 grays of radiation when in a liquid culture, Daly told Live Science. For comparing, a dose of five gray would kill a man.

Daly and his colleagues dried and froze
D. radiodurans
and and so bombarded the bacteria with both gamma radiation and proton radiation, mimicking cosmic radiations from deep space and solar radiation from the dominicus. They constitute that dried and frozen
D. radiodurans
could survive a heed-boggling 140,000 grey of radiations. That’s equivalent to the dose from 1.v million years on the Martian surface and 280 million years 33 feet beneath the surface, where the only radiation is from the radioactive decay within rocks and minerals.

The organisms survive irradiation in two ways, written report co-writer
Brian Hoffman, a pharmacist at Northwestern University, told Live Scientific discipline. First, they accept multiple copies of their genomes, providing a backup for any bits damaged by radiation. Second, they accumulate big amounts of manganese antioxidants, which capture damaging molecules created by radiation. The capture of these molecules prevents damage to the proteins that practise Deoxyribonucleic acid repair for the organism.

“The Dna is organized to exist repaired, and these manganese antioxidants protect the proteins that do the repair,” Hoffman said.

Life on Mars

NASA’south Perseverance rover investigates a rocky outcrop in Mars’ Jezero Crater, looking for potential signs of ancient microbial life.

(Paradigm credit: NASA/JPL-Caltech/ASU/MSSS)

D. radiodurans
evolved on World, where the atmosphere protects the planet and its organisms from the worst radiation. (The bacterium probably evolved to withstand damage during dry periods, and the radiations resistance is merely a side effect of that evolution, Daly said.) Any Martian leaner would have had to evolve in an surroundings without that protection and likely would have had to evolve like radiations resistance, Hoffman said.

Mars has non had widespread liquid water for
2 billion years, so even if ancient life did evolve there, 280 million years is yet as well curt to suggest that the planet hosts a plethora of bacteria just waiting to spring back to life. Only considering Mars has a very thin atmosphere, meteorites rain onto the planet’s surface regularly, Daly said. The rut and liquid water released by those impacts could potentially wake up dormant bacteria in the subsurface and allow for a temporary flourishing of life.

Even if this temporary haven theory isn’t truthful, the long-lasting potential of bacteria on Mars means that $.25 and pieces of ancient life could yet exist present as traces in the rocks, Hoffman said. Dna and other signatures of life could be every bit fragments, fifty-fifty if the organisms were long-expressionless.

The findings too have implications for preventing Mars from becoming contaminated with Globe bacteria, according to the written report authors. Any
D. radiodurans
that hitched a ride on a Mars rover would likely survive the trip from Earth to the Ruby Planet. (Other microorganisms, such as
Escherichia coli
and some
Bacillus
species, could as well last thousands of years on the Martian surface if stale and desiccated, the researchers found.)

As more missions aim to render samples from Mars to Earth, it will be important to ensure that Earth microorganisms aren’t accidentally hauled to Mars and and so mistaken for extraterrestrials, said
John Rummel, a senior scientist at the SETI Establish and former planetary protection officer for NASA. Rummel was non involved in the new study, merely he oversaw its editing at the journal
Astrobiology.

“The round-trip tourist organism is a problem here,” Rummel said. “And nosotros have to exist careful near how we bargain with that.”

Stephanie Pappas is a contributing writer for Live Science, covering topics ranging from geoscience to archaeology to the human brain and behavior. She was previously a senior writer for Live Science but is now a freelancer based in Denver, Colorado, and regularly contributes to Scientific American and The Monitor, the monthly magazine of the American Psychological Association. Stephanie received a bachelor’s degree in psychology from the University of South Carolina and a graduate certificate in science communication from the University of California, Santa Cruz.

Source: https://www.livescience.com/mars-microorganisms

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