Unknown bacteria have lived in enormous cave crystals in Mexico for 50,000 years under harsh conditions, says a new study. This discovery suggests that life beyond our planet—where the environment would be similarly extreme—might exist. The findings were presented at the American Association for the Advancement of Science annual meeting in Boston.
A group of bacteria have been discovered in enormous crystals in caves located in Chihuahua, Mexico. The researchers behind the findings estimate their existence at tens of thousands of years.
Furthermore, the microbes are peculiar in that their characteristics are in stark contrast with those of living organisms on Earth; one of the authors, astrobiologist Penelope Boston, describe them as being “extraordinary” because they do not bear resemblance to any known genuses.
Boston and her team came across these special bacteria in the Naica lead, silver and zinc mine where they have been investigating microscopic life for years now. They ultimately found strange microorganisms in huge crystals of calcium sulphate in the cave. The bacteria appeared to have remained there for about 10,000 to 50,000 years, “sleeping beauties” in the crystals, lying at 100 to 400 metres below the surface of the Earth where they would thrive in temperatures of 45° to 65° Celsius. Boston explains that they were not dead, and were, thus, revived and regrown in laboratory.
If this research is confirmed, the bacteria would feature among the most resilient extremophiles known to us.
The genetic material of these bacteria was examined, together with that of other organisms coming from elsewhere in the cave. The results show that the microbes inside the crystals were genetically different from the others, including those that were lying outside the crystals. As the scientists persevered in unravelling the mystery of the microbes, they found that their closest relatives resided in caves in other parts of the world, or in volcanic soils, or in environments with the compound toluene on which the organisms feed.
This study is also pertinent to the search of life beyond Earth. The great divergence of the bacteria from other forms of life on our planet opens the door to understanding the resilience of living organisms in extreme environments; these harsh conditions have been extended to life beyond the Earth.
“Any extremophile system that we’re studying actually allows us to push the envelope of life further,” says Boston. “We add it to this atlas of possibilities that we can apply to different planetary settings.”
The fact that some bacteria are able to resist the harsh conditions of certain apparently-uninhabitable environments on Earth makes the possibility of life on other planets less and less far-fetched.
“If you took some of these organisms from Earth and put them elsewhere, they may do just fine,” says Boston. That’s not so great for studying any native life that might be there. The Earth-based life could take over and contaminate those worlds.