Life Confirmed At Extreme Depths 273
SEWilco writes "A few years ago the life forms around deep-ocean thermal vents were a surprise. Now ancient bacteria alive in rock 2 miles down have been found. The story is in the San Francisco Chronicle. It is also at Nature.Com, but that server is already rejecting connects. Other bacteria survived frozen in the pressures of an ocean 100 miles deep. This increases the known limits of where life can exist on any planet. Thomas Gold undoubtedly is not surprised at hot, deep bacteria living on hydrogen."
100 miles deep?? Explained! (Score:5, Informative)
OK, before we all jump on that "ocean 100 miles deep" claim (as I was about to do), here's the actual quote from the article:
Other bacteria, frozen into chunks of ice in a Washington laboratory, have thrived inside a high-pressure container and went right on reproducing after they were exposed to pressures equivalent to life at the bottom of an ocean 100 miles deep.
So they aren't really claiming to have found oceans 100 miles deep.
Here's the text if the link is down: (Score:5, Informative)
San Francisco, December, 2002
Goldmine yields clues for life on Mars
Radioactive bacteria live deep in the Earth - and maybe elsewhere.
9 December 2002
TOM CLARKE
Mine dwelling bacteria may be similar to the first life on Earth
© GettyImages
There are tiny creatures living off radiation in ancient pockets of water several kilometres beneath the Earth's surface, say researchers.
The microbes seem to have been isolated for hundreds of millions of years. Similar conditions might exist beneath the surface of Mars.
"Anywhere you have a crust with uranium and water in it, you have the potential for life," microbiologist Tullis Onstott, of Princeton University, New Jersey, told this week's American Geophysical Union in San Francisco.
As you go deeper, the chemicals essential for normal life - organic matter and oxygen - disappear. And you get crushed and cooked, as temperature and pressure rise.
Microbes have been found a kilometre or so beneath the Earth's surface before. But cost and contamination with shallower bugs have hindered scientists looking deeper for life.
Working with miners in the world's deepest holes - 3.5 kilometre-deep South African goldmines - Onstott and his colleagues found hot water rich in bacteria.
The water is loaded with dissolved hydrogen gas, at a concentration up to a hundred million times higher than normal. Radioactive isotopes in the water show that the gas could only have formed by radioactive energy from surrounding uranium deposits splitting the water into hydrogen and oxygen, argues Onstott.
Researchers had speculated that bacteria might make hydrogen in this way, but it has never been seen before. "It's a completely novel system for supporting life," says John Baross, who studies deep-sea bacteria at the University of Washington in Seattle.
The mine-dwelling bacteria are hard to grow in the lab. Genetic evidence suggests that some of the microbes are related to a species called Pyrococcus abyssi, which lives in hot, deep-sea vents.
These bacteria are thought to be similar to the first life on Earth. They use hydrogen and sulphur to survive without oxygen.
Other genetic sequences of microbes in the mine water are unlike those of any other species. Onstott says that he would not be surprised if the mine contained new species with new types of metabolism.
Radioactive dating by Onstott's colleagues suggests that some pockets of mine water have been isolated for several hundred million years. "The dinosaurs came and went while this water has been down there," he says.
If the microbes can be grown and their workings probed, they should provide new insights into primitive life, Baross adds.
Missions to Mars could look for life by sniffing for hydrogen seeping up from deep in the planet's crust, says Onstott. Mars has some water and uranium, although less than Earth.
© Nature News Service / Macmillan Magazines Ltd 2002
Chemosynthesis resources (Score:5, Informative)
Quick image summary of chemosynthesis for the bored [bigelow.org].
Re:Life can be hardy... (Score:2, Informative)
There is a large lake under the Antarctic icepack. There is considerable debate on whether to drill through 4 miles of ice to get samples of the ancient water, and possibly find ancient bacteria. The anti-drilling side points out that any drilling raises the possibility of contamination with modern bacteria.
Re:Life can be hardy... (Score:3, Informative)
DR SERBAN SARBU (Cave Biologist): We very soon realised that in fact this cave had never had an entrance, a natural entrance, was never opened to the surface and this artificial shaft that we descended was the only possible access into the system.
NARRATOR: It was like a bubble trapped in rock. Until it was broken into nothing from the surface had got into it, perhaps for millions of years. What they had found was a world as dark and isolated as Lake Vostok. To begin with they found nothing out of the ordinary, just a series of cramped tunnels. But when they arrived at a small pool there was a surprise in store for them.
SERBAN SARBU: The first surprise that I experienced was that we found a lot of animals present and when I say animals I think of spiders, centipedes, wood lice.
It wasnt in Vostok, it was in Romania.
Mirror of SF article (Score:3, Informative)
Microbes thrive in the harshest environments Research findings give scientists hope of discovering life on planets
Scientists pondering the possibility of life on distant planets have discovered colonies of earthly microbes thriving in more extreme environments than any they have found before.
-- Bacteria are busily reproducing in the total darkness of water- bearing rocks 2 1/2 miles deep inside a South African gold mine, where the rocks themselves have apparently been isolated from the outside atmosphere for about 400 million years.
-- Other bacteria, frozen into chunks of ice in a Washington laboratory, have thrived inside a high-pressure container and went right on reproducing after they were exposed to pressures equivalent to life at the bottom of an ocean 100 miles deep.
The search for these hardy microbes on Earth -- known to science as "extremophiles" -- has been a high-priority project for NASA space planners, whose unmanned planetary probes have already been seeking evidence of life on Mars as well as Europa and other ice-covered moons of Jupiter.
DEEP PROBE
And the NASA spacecraft called Cassini, now on its way to explore the ringed planet Saturn, will be sending a probe deep beneath the thick atmosphere of Titan, one of Saturn's major satellites, to learn whether some form of life -- or at least life's essential chemicals -- might lie on that mystery moon's surface.
Scientists have long been wondering just what kind of life they might expect and what kind of unearthly conditions such living organisms might be able to withstand.
Until now, researchers in NASA's Astrobiology Institute, whose headquarters are at the Ames Research Center in Mountain View, and also at the nearby independent SETI (Search for Extra-Terrestrial Intelligence) Institute have speculated, theorized and experimented with various concepts for life in extreme environments.
Other scientists have already found microbes thriving in deep mines, in the boiling waters of Yellowstone's geysers, in the sub-zero dry valleys of Antarctica, in the saltiest of brines and the driest of deserts far from any water at all.
At the annual meeting of the American Geophysical Union in San Francisco this week, where nearly 10,000 scientists have gathered to report research in every discipline from space physics to seismology to oceanography, some of the scientists were reporting on the possible conditions for life in outer space.
BACTERIA IN DEEPEST MINES
Tullis C. Onstott , a Princeton University geologist reported on the international team that found the bacteria living in the bottom of the deepest gold mines in South Africa.
The mines' rock formations, Onstott said, are about 2.7 million years old, and vast quantities of salt water circulate through them at temperatures of about 135 degrees Fahrenheit.
The scientists drilled boreholes into the blackness of fracture zones in the rocks at the bottom of those mines to obtain more than 100 samples of water and gas, and they found bacteria there thriving on enormous concentrations of hydrogen that provided them with energy for growth, Onstott said.
In another report from the Geophysical Laboratory at the Carnegie Institute of Washington, Anurag Sharma described the "interesting effects on cellular physiology" that he and his colleagues at the institute observed during their experiments with two species of bacteria under high pressure.
INHABITANT OF HUMAN GUT
One species was the common Escherichia coli , well known as an inhabitant of the human gut, and the other was Shewanella oneidensis, which the Department of Energy hopes to use in its efforts to clean up uranium from contaminated wastes at the old World War II Hanford reactor sites in Washington state.
Both species, Sharma said, were exposed to extremely high pressures inside the water cores of ice blocks and continued healthily reproducing after the ice was thawed and the pressure was reduced to normal.
Re:Um, the Mariana Trench? 24 miles deep? (Score:5, Informative)
The complete write up is here. [extremescience.com] The Mariana Trench is a fairly large subduction feature; the Challenger Deep being the deepest point.
BTW, 35,813 / 5,280 = 6.7827 miles (which would be somewhat shy of 24).
Re:Life can be hardy... (Score:3, Informative)
Cave critters without eyes are not new. The new thing in this was that there were hydrogen sulfide eating bacteria which formed the base of the food chain.
Pity you didn't put that in your original post. It would have been quite interesting. Consider this: the same article has speculation that Lake Vostak may have been a rift valley. That might imply the same sort of hot springs which made the ecosystem in Romania possible.So you read the article, but didn't summarize it well enough for me to be able to tell what your point was. Sorry for the unjustified criticism.
You have it right! Mostly (Score:3, Informative)
Key Distinction (Score:3, Informative)
Implications for life's origin (Score:4, Informative)
This theory is being contested, as described in this article [bbc.co.uk], which claims that life may have first arisen in the depths of the ocean, sheltered in a pre-cellular state inside of iron sulphide pockets. Since life can survive beneath the surface, and if it can arise without the need for an atmosphere, then it might indeed exist almost anywhere that liquid water is present.
That is utterly impractical; 3 other things (Score:4, Informative)
Firstly, even an ELE wouldn't blot out the sun COMPLETELY. Secondly, it would only do so for a relatively short period of time - after a century at most, photodensity at the equator would be up to 50% of present levels (enough to farm algae.)
Now, it is true that these chemosynthetic bacteria are a sustainable source of calories, and probably convert geothermal energy (which is where the chemicals they eat come from, in an eventual sense) to sugar at a more efficient rate than a geothermal powerplant could. So, if the earth were ripped from the sun, you might be reduced to this as an option.
However, the industrial costs to recover the buggers would be fucking immense! The technology required simply to break even on drilling up all that rock - I don't want to go there. The geysers at yellowstone don't produce surplus calories to feed very many people.
We'd be better off stockpiling glucose, or making it chemically from energy produced by nuclear / petrochemical reactors.
Secondly, in either event, write off 99.95% of the human race. Waive, chilren.
In the event of an ELE, the remnant of the human race can live on stored food, or on truly synthetic nutrients (eating electricity is what this amounts too) until the particulate level drops enough to begin farming again, less than a century if you're willing to live on strained algae.
In the event of a nuclear winter, same story except your "farms" have to be enclosed to prevent the crops from being irradiated, and they have to be on land. If the rest of the world is tenderly merciful with Australia you might be able to grow food outdoors pretty quickly, mate.
Sundry #1)
Most of these bacteria are archaebacteria. They come from the SAME great lineage of life (there are two - archaea and eubacteria) as we do, or at least as our cellular DNA. These deep dwelling bacteria are more closely related to you or I than they are to the bacteria with which most of us are familiar in our day to day lives. That's not very close - still about a billion years, give or take.
Sundry #2)
This means that although these bacteria dwell deep beneath the earth, and may very well out-mass all terrestrial life, they are DESCENDED from shallow-water dwelling organisms, just like we are. Life could adapt and survive beneath the crust of IO, but that does NOT mean that it could ARISE there.
Sundry #3)
The pressure-survivability of bacteria is a cute trick that should surprise no-one. Bacteria are just soap bubbles full of protein. Extremely TINY soap bubbles. There are three ways to kill them:
1) Pop the soap bubble. Heat can do this, or sound waves, but not pressure the likes of which can be found on earth; the soap bubble is elastic. This doesn't mean the bacteria can BREED under very high pressures (though some can) merely that high pressure won't kill them.
2) Crunch up the protein. Proteins are just chemicals, so again, heat can destroy them, but pressure can't; extremely high pressure might cause lethal aggregation of proteins but evidently it doesn't. Enough TIME will ruin the proteins.
3) Crunch up the DNA. Heat, not pressure! Vibration can do this as well. Mostly, time can be a culprit here.
So, a bacteria might survive the high pressures of being embedded inside a piece of precambrian rock, unable to reproduce. However, TIME, by way of random chemical events, would destroy the DNA inside the bacteria.
The DNA inside of any bacteria able to reproduce is maintained by evolution - but that which maintains it also changes it.
The upshot - it is impossible to recover DNA from an organism that lived millions of years ago. Sorry.
Re:100 miles deep?! (Score:2, Informative)