bacteria could survive for 280 million years under its surface

bacteria could survive for 280 million years under its surface

Deinococcus radiodurans, nicknamed “Conan the Bacteria” due to its resistance to ionizing radiation — © Michael J. Daly / USU

A recent series of experiments indicated that dried, frozen bacteria could survive the intense radiation hitting Mars for a much longer period than expected.

Outstanding resistance

Until now, most experiments aimed at evaluating the ability of microorganisms to survive intense radiation from March involved hydrated terrestrial bacteria. Made at room temperature, these suggested that the most robust of them could survive up to a million years under the surface of the red planet.

For this new study published in the journal Astrobiology, Brian Hoffman and his colleagues at Northwestern University took a different approach, drying and freezing different bacteria and yeasts, then exposing them to levels of radiation similar to those that would reach the Martian subsurface. Experience has shown that under such conditions these life forms could persist for about 280 million years.

A phenomenal increase in strength occurs when you get rid of the water and cool it all down, similar to the freeze-drying process that extends the shelf life of food says Hoffman. ” Mars being dry and cold, it is likely that the bacteria likely to be there are also. »

— Dotted Yeti /

According to the team, if the freeze-dried bacteria were warmed and exposed to water during this time, they would come out of their dormant state, implying that the impact of a meteor with a low concentration of water could ” wake “. “ The probability of them still being alive was zero, it is now significantly greater than zero “Hoffman believes.

Important implications for the search for traces of life on the Red Planet

With previous work suggesting the Red Planet dried up some 2-2.5 billion years ago, it’s likely that even the toughest Martian bacteria are long dead. However, the results of the new experiments have important implications for the search for traces of life on the red planet.

If Martian life ever existed, and even if viable life forms are not currently present on the planet, their macromolecules and viruses would survive much, much longer, increasing the chances of uncovering evidence of their past existence. », Underlines Michael Daly, co-author of the study.

According to the researchers, the possibility that terrestrial organisms could sustainably endure conditions comparable to those of Mars also means that any mission to the red planet will have to be carefully thought out in order to reduce the risks of contamination, which would prove to be almost permanent.