19.02.2017
Lifeforms which have been living inside crystals for up to 60,000 years have been revived by NASA, raising hopes that alien organisms could be found in extreme environments on other planets.
Penelope Boston, the director of NASA's Astrobiology Institute, and her team have spent years exploring Mexico's Naica Mine in Chihuahua looking for extremophiles, which contain caves as large as cathedrals.
The mine is filled with giant gypsum crystals which look so extraordinary that when Dr Boston first saw a picture, she assumed it had was a Photoshop hoax.
But more astounding, was that inside the crystals, tiny bugs were discovered in a state of 'geolatency' - where living organisms remain viable in geological materials for long periods of time.
"Much to my surprise we got things to grow," said Dr Boston. "It was laborious. We lost some of them - that's just the game. They've got needs we can't fulfill. That part of it was really like zoo keeping."
Around 100 different bugs, which were mostly bacteria, were found inside crystals, where they had been trapped for between 10,000 and 60,000 years. 90 per cent had never been seen before.
The cave system sits above a large pocket of volcanic magma and is geothermally-heated to temperatures of up to 60C, which has led to astrobiologists dubbing it 'hell'.
Most life could not survive there but scientists have discovered some organisms have evolved to feed on the sulphides, iron, manganese or copper oxide in the cave.
"They're really showing us what our kind of life can do in terms of manipulating materials," said Dr Boston.
"These guys are living in an environment where there's not organic food as we understand it. They're an example at very high temperatures of organisms making their living essentially by munching down inorganic minerals and compounds. This is maybe the deep history of our life here."
Describing working in the cave she said: "It was a transformative experience...it really felt strange. It was a very hard environment to work in, but tear-inducingly beautiful. It's like being inside a geode."
Some of the "sparkling white" giant crystals are as long as five metres.
"I can't even put my arms round the biggest ones," she added.
Other caves detected with "weird life forms" but accessing them was too dangerous.
Scientists said discoveries such as this raised the possibility that dangerous bugs could hitch a ride back to Earth when spacecrafts return from other planets.
NASA has plans to bring back rock and ice samples from Europa, an icy moon of Jupiter, which is one of the best targets in the solar system for life because it has a salty ocean beneath its crust.
Dr John Rummel, from the Seti Institute in Mountain View, California, said it was "pretty easy" for bugs to survive space journeys as long as they are shielded from the sun's ultraviolet radiation.
"If we bring samples back from either Europa or Mars, we will contain them until hazard testing demonstrates that there is no danger and no life, or continue the containment indefinitely while we study the material.
"It is assumed that such life would be hardy - to survive the trip to Earth; not easy - and precautions taken would provide a very high degree of containment.
Quelle: The Telegraph
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Image copyrightPENELOPE J. BOSTON
It is a remarkable discovery in an amazing place.
Scientists have extracted long-dormant microbes from inside the famous giant crystals of the Naica mountain caves in Mexico - and revived them.
The organisms were likely to have been encased in the striking shafts of gypsum at least 10,000 years ago, and possibly up to 50,000 years ago.
It is another demonstration of the ability of life to adapt and cope in the most hostile of environments.
"Other people have made longer-term claims for the antiquity of organisms that were still alive, but in this case these organisms are all very extraordinary - they are not very closely related to anything in the known genetic databases," said Dr Penelope Boston.
The new director of Nasa's Astrobiology Institute in Moffett Field, California, described her findings here at the annual meeting of the American Association for the Advancement of Science (AAAS).
Image copyrightMIKE SPILDE
First opened by miners looking for silver and other metals a hundred years ago, the deeply buried Naica caves are a key interest to scientists fascinated by extremophiles - microbes that can thrive in seemingly impossible conditions.
The environment is hot (40-60C), humid and acidic. With no light at depth, any lifeform must chemosynthesise to survive. That is, it must derive the energy needed to sustain itself by processing rock minerals.
Researchers had identified microbes living in the walls of the caves, but isolating them from inside the metres-long crystals is a surprise.
These outsized needles of gypsum have grown over millions of years. They are not perfect. In places they have defects - small voids where fluids have collected and become encased.
Image copyrightMIKE SPILDE
Using sterile tools, Dr Boston and colleagues opened these inclusions and sampled their contents.
Not only did they detect the presence of bacteria and archaea, but they were able also to re-animate these organisms in the lab.
The concern would be that these organisms might simply be the result of contamination, either introduced by the team or the mining operations. But the Nasa director said that the necessary protocols were followed.
Scientists have previously claimed to revive bugs thought to have been dormant for many millions of years. These organisms had been trapped inside salt or ice crystals. All such claims are contentious, but Dr Boston said she was minded to accept them after everything she had seen at Naica and in other similar environments.
What gives her confidence in the status of the Mexican caves is the great diversity of life that seems to exist there.
"Other groups have shown there are lots of viruses in these caves and what that says to me is that these are fully fledged microbial communities that have their viral load just like every other community does. So, that's another aspect of this that argues against casual contamination," she told reporters.
Working for Nasa as an astrobiologist, she is clearly interested in the relevance of such finds to the search for life beyond Earth.
"The astrobiological link is obvious in that any extremophile system that we're studying allows us to push the envelope of life further on Earth, and we add it to this atlas of possibilities that we can apply to different planetary settings."
Image copyrightMIKE SPILDE
Many scientists suspect that if life does exist elsewhere in the Solar System, it is most likely to be underground, chemosynthesising like the microbes of Naica.
Dr Boston said her team was about to submit a paper on the caves to a relevant journal.
In her discussion with reporters she lamented the fact that the crystal complex had become flooded following the recent cessation of mining activities, preventing any further access.
"It is tear inducingly beautiful down there. I wrote several poems about it actually."
Image copyrightMIKE SPILDE
Quelle: BBC
Siehe auch unser Blog-Beitrag von 2011:
http://hjkc.de/_blog/2011/09/13/planet-erde---naica-mine-in-mexiko/