50,000yo microbes discovered in Mexican cave

Mysterious microbes and viruses discovered in a meandering Mexican cave system could be up to 50,000 years old, according to new research.

The ancient specimens were discovered by researchers from NASA’s Astrobiology Institute in an abandoned lead and zinc mine in Naica, northern Mexico. If as old as scientists believe, the microbes have likely survived the extremely harsh conditions for millennia on minerals such as iron and manganese.

“It’s super life,” said the head of the Astrobiology Institute, Penelope Boston, at the American Association for the Advancement of Science conference in Boston on Friday, reported AP.

The archaic life forms consist of 40 different strains of microbes and viruses and are so rare their closest relatives still differ genetically by 10%, leading Boston to say it’s like comparing humans to mushrooms.

"They're an example, at very high temperatures, of organisms making their living essentially by munching down inorganic minerals and compounds," said Boston. "This may be the deep history of our life here."

The discovery is the culmination of nine years of research, although it has yet to be peer reviewed, or published in a scientific journal, as Boston did not offer her work for review before Friday’s announcement.

If confirmed, however, it’s yet another indication of how life can survive in extreme conditions on Earth and possibly off-world in places like Saturn’s moon, Enceladus and dwarf planet Ceres.

It wasn’t an easy task retrieving the microbes, with temperatures in the abandoned mine, which was up to 800 meters (2,625 feet) deep, so hot that scientists had to wear suits comparable to astronauts and have ice packs all over their bodies.

The team could only work for about 20 minutes at a time before leaving for a 'cool' room, still a roasting hot 38C (100F).

Undeterred by the harsh conditions, Boston is busy studying other forms of microbial life in the US, Ukraine and around the world, saying that “It’s simply another illustration of just how completely tough Earth life is.”