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October 9, 2011
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Jennifer Frazer is a AAAS Science Journalism Award-winning science writer. She has degrees in biology, plant pathology/mycology, and science writing, and has spent many happy hours studying life in situ.
Jennifer Frazer is a AAAS Science Journalism Award-winning science writer. She has degrees in biology, plant pathology/mycology, and science writing, and has spent many happy hours studying life in situ.
For years, ripples at the surface of the Dead Sea hinted there was something mysterious going on beneath its salt-laden waters. But in a lake where accidentally swallowing the water while diving could lead to near-instant asphyxiation, no one was in a hurry to find out what it might be.
This year, some intrepid divers changed that, stumbling onto a geological and biological treasure and capturing it on video. We’ll get to that in just a moment.
Don't drink the water: the Dead Sea. Creative Commons xta11. Click Image for License and link.
This is the Dead Sea. As you can see, it appears quite dead. There are no plants, fish, or any other visible life in the sea. Its salt concentration is a staggering 33.7%, 8.6 times saltier than ocean water, which is only about 3.5% salt. The stones at the water’s edge encrusted in salt are a good clue in that department. As a result, the Sea is famous for its body buoyancy properties, as people who take an exploratory dip generally find themselves riding high on its waters.
The Dead Sea is also the lowest point on earth, and getting lower every year, as water that would ordinarily fill it by flowing in from the Jordan River has been diverted to quench the thirst of Israel, Jordan, and Palestine. Every year, the lake drops over a meter per year. If this goes on long enough, the Sea could face Owens Lake’s and the Aral Sea’s fate: becoming a wind-swept salt flat. Yet, for now, life goes on.
Biologists have known since the 1930s the lake is “not dead yet”. Instead, it’s full of microbes that get along quite happily in the salty soup, for it keeps out competitors that would take over in a more hospital aqueous environment. In general, the water contains 1,000 to 10,000 archaea* per ml, a much lower concentration of life than in seawater, but quite respectable, all in all, for a place where one molecule in three is not water. Occasionally, when conditions are right, the sea blooms red with life. This happened in 1980 and 1992.
In any case, divers from Israel and Germany finally braved the waters this year to see what might have been causing the aforementioned concentric-ringed ripples observed near shore. They were not disappointed. This is what they found (hit the button at the bottom right corner of the youtube player to watch it in uber-super-cool full screen mode):
These are freshwater springs, jetting into the bottom of the Dead Sea from inside craters. Found as deep as 100 feet from the surface, the springs lie at the base of craters as large as 50 feet wide and 65 feet deep. As can be seen, a variety of interesting geological formations surround them.
The springs roil the waters they flow into in a phantasmal slipstream. Starting at about 2:00, you can see it coiling and mixing like it’s hundreds of degrees hotter or more sugary than the surrounding water. But no, it’s just that much less salty (and dense). (There’s a famous scene in the “Caves” episode of Planet Earth that vividly illustrates salinity gradients (haloclines) in the cenotes of Mexico too — go track down a copy if you can).
What makes this place biologically amazing was the life they found near the plumes.
A nice article on the discovery at National Geographic notes:
The top of the springs’ rocks are covered with green biofilms, which use both sunlight and sulfide—naturally occurring chemicals from the springs—to survive. Exclusively sulfide-eating bacteria coat the bottoms of the rocks in a white biofilm.
Bacterial mats or biofilms have never been found in the Dead Sea before. You can see the films of green photosynthetic bacteria on top of a rock and a film of white sulfide-oxidizing bacteria underneath it in the very last scene of the movie. Go have a peek.
Not only have the organisms evolved in such a harsh environment, Ionescu speculates that the bacteria can somehow cope with sudden fluxes in fresh water and saltwater that naturally occur as water currents shift around the springs.
Ionescu further pointed out that all known hard-core halophiles, or salt-loving microbes, die if you put them in freshwater, and vice versa. How these microbes are able to withstand what must be wicked shifts in salinity on an ongoing basis is anyone’s guess. This reminds me of the creatures at deep sea vents that must withstand massive fluctuations in temperature as ventwater hundreds of degrees hotter than the surrounding seawater shifts back and forth. I’ll say it along with Jeff Goldblum once more: “Life finds a way.”
Whatever they are — and scientists are planning to go back to find out more — they are not like the microbes found in the rest of the sea nor like the organisms that cause the sea to occasionally bloom red. And they are very diverse — much more so than their halophilic neighbors.
The article also notes that the Dead Sea’s waters are particularly caustic and difficult for divers, which, as a new diver myself, I found particularly interesting/horrifying. In addition to having to weight yourself down incredibly — on the order of 90 pounds; when I dove in Hawaii last year, I used about 12 pounds — Dead Sea water is not something you want coming into contact with your face. Ever.
Divers will also need to wear full face masks to protect their eyes and mouths. That’s because accidentally swallowing Dead Sea salt water would cause the larynx to inflate, resulting in immediate choking and suffocation.
Oh good.
Likewise, the intensely salty water would instantly burn and likely blind the eyes—both reasons why Dead Sea swimmers rarely fully submerge their bodies, Ionescu noted.
I well recall practicing losing, replacing, and clearing my mask of water at depth when I was getting certified. I guess in the Dead Sea, that’s more of the nuclear option in case of leak or “wardrobe malfunction”.
For more information on the springs (which have not be formally published in a journal yet), see the scientists’ press releases here and here.
______________________________________________________
*Archaea are a fascinating and huge group of bacteria-like organisms that were only discovered in the 1970s by biologist Carl Woese (“Woes”). If you don’t know about archaea, you should learn more. Trust me.
About the Author: Jennifer Frazer is a AAAS Science Journalism Award-winning science writer. She has degrees in biology, plant pathology/mycology, and science writing, and has spent many happy hours studying life in situ.
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Excellent post. I have only one quibble: Since the purpose of the weights is to counter the buoyancy, if correctly balanced you wouldn’t feel the mass of the weights while diving any more than diving elsewhere. Of course, when you wanted to get out of the water again, the weights would definitely make it harder.
Link to thisOh definitely. I was just sort of amazed by the *quantity* of weight in proportion to regular seawater. Since you are neutrally buoyant when diving, you wouldn’t feel a thing. However, I think I might need a crane to help me get in and out of the water . . .
Link to this[...] of Life Found at the Bottom of the Dead Sea Fountains of Life Found at the Bottom of the Dead Sea | The Artful Amoeba, Scientific American Blog … Be sure to watch the video. Reply With Quote + Reply to [...]
Link to thisActually, you’d still have the mass of the weights to contend with regardless of them effectively weightless in the water.
Link to this“where one molecule in three is not water”
In my opinion, a salt concentration of 33.7% (weight-based) results in much less than one molcule salt in three.
The main component in the Dead Sea’s salt is magnesium chloride of which one molecule is much heavier as one of water.
Link to thisMaybe they should rename it “the Deadly Sea”.
The diversity around the springs reminds me of rather recently mentioned diversity in caves where bacterial communities seems to thrive, perhaps necessary to cope with especially difficult conditions.
@ Jennifer Frazer:
“I might need a crane”.
Good luck with that, I think cranes inhabit freshwater (wetland).
[Really, I'm not sure if I want to rely on _anything_ mechanical around that little water activity. Salt corrosion _and_ salt depositions. Hope the scientists budget for new gear!]
Link to this[...] مرده به ندرت تمامی بدنشان را در آب فرومیبرند». منبع: Scientific American در همین زمینه: تحول زیستی در ژرفای اقیانوس اطلس [...]
Link to this[...] Fountains of Life Found during a Bottom of a Dead Sea Scientific American [...]
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Link to this[...] et allemands ont bravé ces eaux chargées de sel et ont fait une découverte édifiante: des sources d’eau douce jaillissent, à plus de 30 mètres de profondeur dans des cratères de 15 mètres de largeur et 20 mètres de [...]
Link to thisAn amazing discovery, and it means that there is still hope for the Dead sea. I think that discoveries like this and a win in the New7Wonders of Nature (you can vote here: http://www.facebook.com/VoteDeadSea )will bring more funds to research the place.
Link to thisI find it odd that this article, and the research it covers, both offer a compelling new reason to make sure the Dead Sea isn’t allowed to dry up from water being diverted, in these amazing new life forms at it’s bottom, but also that it offered reasons that it might not need protecting by discussing the freshwater vents within it. I also find it interesting that I managed such a long run-on sentence without seriously considering to edit it to smaller ones.
Link to this[...] et allemands ont bravé ces eaux chargées de sel et ont fait une découverte édifiante: des sources d’eau douce jaillissent, à plus de 30 mètres de profondeur dans des cratères de 15 mètres de largeur et 20 mètres de [...]
Link to this[...] have found a variety of microbial life at the bottom of (ironically) the Dead Sea, around freshwater springs at the sea’s floor. Since the Dead Sea has incredibly high salt [...]
Link to this[...] bravé ces eaux chargées de sel et ont fait une découverte édifiante: des sources d’eau douce jaillissent, à plus de 30 mètres de profondeur dans des cratères de 15 mètres de [...]
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