Life forms that could be 50,000 years old found in Mexican caves

Ancient microbes trapped in crystals live on iron and manganese, say researchers


In a Mexican cave system so beautiful and hot that it is called both fairyland and hell, scientists have discovered life trapped in crystals that could be 50,000 years old.

The ancient microbes were found dormant in caves in Naica, in Mexico’s northern Chihuahua state, and were able to exist by living on minerals such as iron and manganese, said Penelope Boston, head of Nasa’s Astrobiology Institute.

“It’s super life,” said Ms Boston, who presented the discovery on Friday at the American Association for the Advancement of Science conference in Boston. She said the creatures were like time machines.

If confirmed, the find is yet another example of how microbes can survive in extremely punishing conditions on Earth.

Though it was presented at a science conference and was the result of nine years’ work, the findings have not yet been published in a scientific journal and have not been peer reviewed. Ms Boston planned more genetic tests for the microbes she revived both in the lab and on site.

The life forms – 40 different strains of microbes and even some viruses – are so strange that their nearest relatives are still 10 per cent different genetically. That made their closest relative pretty far away, about as far away as humans were from mushrooms, Ms Boston said.

The life forms included 40 strains of microbes and some viruses. Photograph: Penelope Boston/PA Wire
The life forms included 40 strains of microbes and some viruses. Photograph: Penelope Boston/PA Wire

The Naica caves – an abandoned lead and zinc mine – are 800 metres deep. Before drilling occurred by a mine company, the mines had been completely cut off from the outside world.

Some were as vast as cathedrals, with crystals lining the iron walls. They were also so hot that scientists had to don cheap versions of space suits to prevent contamination with outside life and had ice packs all over their bodies.

Ms Boston said the team could only work about 20 minutes at a time before ducking to a “cool” room that was about 38 degrees. Temperatures in the cave system can reach 60 degrees.

Nasa would not allow Ms Boston share her work for outside review before Friday’s announcement so scientists could not say much.

One University of South Florida biologist, Norine Noonan, who was not part of the study but was on a panel where Ms Boston presented her work, said it made sense.

“Why are we surprised?” Ms Noonan said. “As a biologist I would say life on Earth is extremely tough and extremely versatile.”

This is not the oldest extreme life. Several years ago, a different group of scientists published studies about microbes that may be half a million years old and still alive.

Those were trapped in ice and salt, which isn’t quite the same as rock or crystal, Ms Boston said.

The age of the Naica microbes was determined by outside experts who looked at where the microbes were located in the crystals and how fast those crystals grow.

Guardian service/AP