NASA researchers have found microbial organisms trapped in large beams of selenite deep inside a cave in the Naica mine, Mexico. The life-forms that thrive on iron, sulfur and other chemicals are still active, according to calculations, even though they might be up to 50,000 years old.
If the scientists are correct, the discovery builds on the evidence that microbial creatures can survive on Earth against harsher conditions than what was previously thought possible.
NASA Astrobiology Institute Director Penelope Boston commented on the findings presented at the American Association for the Advancement of Science conference in Boston last Friday.
“These organisms have been dormant but viable for geologically significant periods of time, and they can be released due to other geological processes. This has profound effects on how we try to understand the evolutionary history of microbial life on this planet,” said Mrs. Boston, National Geographic reported.
The uncovering of the microbes might pose some risks about the efforts to explore other worlds in the solar system in the quest for extraterrestrial life, warned Boston.
There’s always a possibility that a mission drilling into another planet could carry invasive and highly durable creatures along with them, even if NASA takes rigorous steps to sterilize the spacecraft. It would be difficult to determine whether the missions are detecting alien life or just life brought with them from Earth.
The Discovery
The expedition was carried out inside the Cave of Crystals, a part of the Naica mine located in the northern state of Chihuahua. Researchers were pumping groundwater out of the giant underground caverns to pull up lead and silver without anticipating they would unearth a labyrinth of giant white crystals.
Explorations retrieved microbial creatures trapped within the crystals- some of which reached more than 30 feet in height- floating in pools of fluids. The microbes were able to exist by living on minerals like iron and manganese, adapting to endure extreme environments.
In 2008 and 2009, Boston and her team had taken samples from the pockets of liquid back to their labs to conduct a proper analysis, under the sponsorship of New Mexico Tech.
She revealed at the meeting on Friday that they were able to “wake up” the organisms from their slumber, both in the grow cultures at the lab as well as on site.
They learned from their nine years of work that the creatures were genetically distinct from anything known on Earth, although similar to others microorganisms recovered from caves and volcanic terrain.
Previous investigations had dated the oldest crystals in the cave back to half a million years. That crystal growth rate led them to estimate the microbes had been cultivating for as long as 10,000 or 50,000 years.
The results are currently being written for publication, but they have yet to be peer reviewed, a mandatory step in the verification of scientific work. For now, it is not advisable to draw out any conclusions from their findings.
With that in mind, Penelope and her crew plan to continue the genetic tests on the microbes.
Boston finished the meeting by prompting other scientists to continue the work on the “precious resources,” which are the microbes still actively growing.
“We want to make it available to other folks. There’s still a lot of work to do to infer anything about their history and movement and genetic relations,” said Boston in her closing statement, as noted by The National Geographic.
Too good to be true?
There is also one other plausible explanation: that the life-forms didn’t belong to the crystals but came with the water surrounding them.
Microbiologists from France and Spain ventured deep inside the Naica system in 2013 to look for microorganisms in the hot saline springs. What their report showed was that modern-day microbes are also genetically distinct from other known species and they feed off of chemicals in the subsurface as well.
Purificación López-García of the French National Center for Scientific Research in charge of the 2013 investigation is uncertain about the authenticity of the time frame offered by Boston’s study.
“Contamination during drilling with microorganisms attached to the surface of these crystals or living in tiny fractures constitutes a severe risk. I am very skeptical about the veracity of this finding until I see the evidence,” concluded López-García.
To what Boston responded that her team took the necessary precautions to try and avoid contamination. They wore special containment protective suits and sterilized the drills and the surfaces of the crystals with hydrogen peroxide and sometimes fire.
Boston explained that the cave organisms her team had cultured and brought back to life in the lab are not identical to those in the fluid inclusions, proving that the ones they were seeing came from inside the crystals.
Unfortunately, the Cave of Crystals is once again flooded under groundwater, after the mine stopped being profitable and operations at Naica ceased. That makes going back to collect additional samples a difficult option.
At the same time, Brent Christner, a microbiologist at the University of Florida, argued that the concept of reviving such organisms doesn’t seem out-of-mind since resuscitation from older geological material has been introduced before. The amount of skepticism is relatively linked to the age of the claim, confessed Christner to The National Geographic.
No one is exactly sure how long any life can survive in those unforgiving conditions. Even when sleeping, organisms need food or their cells will eventually start to degrade.
The small creatures from Naica could have slowed down their metabolism enough to live for millennia, but this hypothesis remains unconfirmed. They could have been using the limited energy sources to distend their living, maybe eating their dead counterparts that didn’t make it through.
Source: National Geographic