Microbes Could Have Survived Millions of Years Below Mars’ Surface | CNN

Sign up for CNN’s Wonder Theory science newsletter. Explore space with news about fascinating discoveries, scientific advances, and more. CNN — New research suggests that ancient bacteria may be sleeping beneath the surface of Mars, where it has been protected from harsh radiation from space for millions of years. Although no evidence of life has been found on the Red Planet, the researchers simulated conditions on Mars in the lab to see how bacteria and fungi could survive. Scientists were surprised to find that bacteria could survive for 280 million years if they were buried and protected from ionizing radiation and solar particles that attack the Martian surface. The study’s findings suggest that if life existed on Mars, the evidence could still exist underground on Mars and could be explored by future missions when drilling into Martian soil. Mars may have been a more hospitable environment for life billions of years ago, including its surface atmosphere and water, but today the red planet is more of a frozen desert. The planet’s dry mid-latitudes have average temperatures of minus 80 degrees Fahrenheit (-62 degrees Celsius). And because Mars has a thin atmosphere, there is a constant threat of radiation. Study co-authors Brian Hoffman, Charles E. and Emma H. ​​Morrison, professor of chemistry and molecular life sciences at Northwestern University, said: “There is no running water or significant amounts of water in the Martian atmosphere, so cells and spores will dry up.” said. Weinberg College of Arts and Sciences announced in a statement. “It’s also known that Mars is actually deeply frozen because the surface temperature of Mars is close to that of dry ice.” The team determined the survival limit of microbes when exposed to ionizing radiation, such as those experienced on Mars. The team then simulated the Martian surface environment with six types of bacteria and fungi found on Earth. All of this is zapped with protons or gamma rays to mimic cosmic radiation. A clear winner emerged: Deinococcus radiodurans. Nicknamed “Conan bacteria” because of their tough nature, these microbes seemed perfectly suited to life on Mars. Because these bacteria are polyextremophiles, they can survive in harsh conditions such as dehydration, acidity and low temperatures. Hardy microbes are among the most radiation-resistant organisms known to science. Previous research has shown that bacteria can survive for 1.2 million years just below the Martian surface in harsh radiation and dry, frozen environments, and millions of years longer than some microorganisms known to survive on Earth . A new study finds that Conan Bacterium can survive to 140,000 units of radiation, 28,000 times higher than radiation exposure levels that could kill humans when dried, frozen and buried deep on the Martian surface. Microscopically, amber-like bacteria can survive on the surface of Mars for only a few hours after relentless exposure to ultraviolet light. The estimated lifespan of Conan Bacterium has increased to 1.5 million years at 4 inches (10 centimeters) below the surface, and about 280 million years when the bacteria are 33 feet (10 meters) below the surface. The journal Astrobiology published a study on Tuesday detailing the finding. The researchers were able to measure how much manganese antioxidants accumulated in the cells of the microorganisms exposed to the radiation. The more manganese antioxidants the researchers found, the more likely the microorganisms were to resist radiation and survive. The genomic structure of Conan Bacterium links chromosomes and plasmids together, meaning that cells remain aligned and can repair themselves after exposure to radiation. And if Conan-like microbes had evolved on Mars billions of years ago, the dormant remnants of bacteria would have slept deep beneath the planet when water was still on the Martian surface. Study author Professor Michael Daly said: “Even though D. radiodurans, buried underground on Mars, could not survive dormant for about 2 to 2.5 billion years after running water disappeared on Mars, this Martian environment is regularly altered by meteorite impacts. melted,” he said. He said he is a Doctor of Pathology at the American College of Health Sciences and a member of the National Academy Committee on Planetary Protection. He suggests that “periodic melting may enable intermittent re-proliferation and dispersal. Also, if life existed on Mars, macromolecules and viruses would survive much longer, even if life didn’t exist on Mars today. This reinforces the possibility that if life evolved on Mars, this could be revealed in future missions.” The findings affect both the return of Mars samples to Earth and missions for crews to land on Mars. The Mars Sample Return Program, an ambitious program jointly run by NASA and the European Space Agency, launches several missions to Mars to collect and return samples collected by Mars rovers. The rover team hopes that rock and soil samples from ancient lakes and delta areas in Mars’ Jezero Crater can determine if life has ever existed on Mars. Samples may contain microfossils of ancient microorganisms. It is also possible that astronauts accidentally pass hitchhiking bacteria from Earth when they land on Mars. “We have concluded that Martian terrestrial pollution is essentially permanent over a period of thousands of years,” Hoffman said. “This could complicate scientific efforts to find life on Mars. Likewise, if microbes evolved on Mars, they could survive to this day. This means returning Mars samples could contaminate Earth.”

#Microbes #Survived #Millions #Years #Mars #Surface #CNN

Leave a Comment

Your email address will not be published. Required fields are marked *