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Mat of microbes the size of Greece discovered on seafloor

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census of marine life microbes mat burrowersGargantuan whales and hefty cephalopods are typically thought of as the classic marine mammoths, but they might have to make way for the mighty microbes, which constitute 50 to 90 percent of the oceans’ total biomass, according to newly released data.

These tiny creatures can join together to create some of the largest masses of life on the planet, and researchers working on the decade-long Census of Marine Life project found one such seafloor mat off the Pacific coast of South America that is roughly the size of Greece.

A single liter of seawater, once thought to contain about 100,000 microbes, can actually hold more than one billion microorganisms, the census scientists reported. But these small creatures don’t just live in the water column or on the seafloor. Large communities of microscopic animals have even been discovered more than one thousand meters beneath the seafloor. Some of these deep burrowers, such as loriciferans, are only a quarter of a millimeter long.

"Far from being a lifeless desert, the deep sea rivals such highly diverse ecosystems as tropical rainforests and coral reefs," Pedro Martinez Arbizu, of the German Center for Marine Biodiversity Research and leader of the Census of the Diversity of Abyssal Marine Life, said in a prepared statement.

Thanks to high-throughput DNA sequencing, researchers have been able to vastly expand their catalogue of marine microbes. "Scientists are discovering and describing an astonishing new world of marine microbial diversity and abundance," Mitch Sogin, of the Marine Biological Laboratory in Woods Hole and leader of the International Census of Marine Microbes, said in a prepared statement.

This genetic data has revealed that there might be as many as 100 times more microbe genera than researchers had assumed. One study conducted in the English Channel landed 7,000 new genera alone. Current estimates place the number of marine microbial species at about a billion, according to a prepared statement by John Baross of the University of Washington and chair of the International Census of Marine Microbes’s scientific advisory council.

And research has yet to plumb the guts and surfaces of more macro ocean life, which, like humans, can play host to billions of microbial cells. The species living on and in "marine animals alone may account for hundreds of millions of microbial species," Baross said. "This is a huge frontier for the next decade."

Despite their small individual size, microbes play a big role in the oceans—and the planet overall. Microbes help to turn atmospheric carbon dioxide into usable carbon, completing about 95 percent of all respiration in the Earth’s oceans. Even those deep in the seafloor, such as the deep-sea burrowers, "help oxygenate sediments and interact with microbes to cycle nutrients and carbon on the ocean floor," Arbizu said. But little is known about these creatures’ susceptibility to the changes in ocean temperatures, dissolved gasses and acid levels that are predicted to occur with climate change.

"Tracking and visualizing such complex populations was impossible 10 years ago," Baross said. "Sequencing allows us to give the equivalent of an Internet URL to millions of microbes, to which we can attach all kinds of other information, like their favorite temperature and amount of salt and light."

The full findings of the census will be presented in October in London. For the coming decade Baross suggests a survey of marine viruses.

Image of loricciferan Culexiregiloricus trichiscalida, which was discovered off the coast of Africa some 4,100 meters below the surface last year through the census, courtesy of Gunnar Gad/Marco Buntzow/German Center for Marine Biodiversity Research/Census of Marine Life

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  1. 1. Broadlands 2:14 pm 04/18/2010

    "Microbes help to turn atmospheric carbon dioxide into usable carbon, completing about 95 percent of all respiration in the Earth’s oceans. "
    Something’s confused here? It is the photosynthesis of marine algae that turns carbon dioxide into "usable carbon" (organic matter). Respiration completes the cycle by using dissolved oxygen to turn organic matter back into carbon dioxide.

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  2. 2. Broadlands 2:30 pm 04/18/2010

    "…man must act now to undo the harm…"

    Could you be specific as to how people should act to reverse your perceived disruption on these tiny life forms?

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  3. 3. j.quasimodo 4:43 pm 04/18/2010

    That great scientist George Carlin said, "We don’t need to save the planet; it will do fine. It will shrug us off like a bad case of fleas."

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  4. 4. Protonius 4:51 pm 04/18/2010

    Some random but related thoughts:

    1. If Shakespeare had been a DNA-insightful poet, perhaps he would have wisely written that "There are more microbial forms — and more discoveries yet to be made — in Heaven and Earth than exist in Your philosophy, Horatio!".

    2. The mysterious, eons old, sealed from the surrounding oceans, and as yet untapped (or so we’re told) LAKE VOSTOK, down in Antarctica: It would seem that the discoveries of countless types of hitherto unknown species of undersea microbes, as noted in the above article, now stands as a poignant and instructive backdrop toward the opening of yet greater vistas of discovery — and of concern as well as enlightenment — if and when LAKE VOSTOK’s shield-like ice-shell is eventually pierced by whichever exploration team succeeds in breaching it. I wonder, to what extent are the above-mentioned discoveries playing into scientific considerations regarding if, and when, and how, the potential bio-life within Lake Vostok should be accessed, explored, researched, utilized, and also protected against?

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  5. 5. reguspatoff 7:27 pm 04/18/2010

    How can this new knowledge of undersea microbes be applied to the water-bearing moons beyond earth’s orbit?

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  6. 6. rvacca 4:30 am 04/19/2010

    Prof Tom Gold in "The Deep Hot Biosphere" (Springer Verlag 1999, Copernicus Books 2001) explained mechanisms by which microorganisms get oxygen from reduction of iron oxides, etc. Also explains hydrocarbons being primordial and abiotic.
    Roberto Vacca, Rome, Italy –

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  7. 7. RJG1 4:31 am 04/19/2010

    Surely the comparison in this article should use the British Standard unit – "the size of Wales".

    This would mean that the mat of microbes is 6.5 times the size of Wales.

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  8. 8. Unksoldr 9:53 am 04/19/2010

    I was taught in Wildlife Biology about density-dependent decimating factors. Basically anytime a species overpopulates it’s environment, something(examples:starvation, disease, psychotic behavior i.e. lemming migrations)will control that population. Man is not exempt from the laws of nature.

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  9. 9. outsidethebox 6:16 pm 04/19/2010

    "Mat of microbes the size of Greece is discovered on seafloor". Was it asking for a bailout?

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  10. 10. FlyGuy 10:07 pm 04/19/2010

    Paragraph 3 "One thousand meters below the SEAFLOOR.??"

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  11. 11. Jokunen 10:44 pm 04/19/2010

    Yeah, there are microbes living kilometers underground and last time I checked, under seafloor counts as underground.

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  12. 12. sinclair 11:21 am 04/21/2010

    So if these huge amounts of biomass have been present in the deep oceans for millions of years, does this mean there could be vast oil fields still to be tapped?

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  13. 13. tacitus5 6:40 am 07/1/2010

    This finding somewhat reminds me of the ecological thriller "The Swarm" by Frank Schtzing (ISBN-13 9780340920756). Even though the microbial mats in reality lack the swarm intelligence that the author suggests in this book, the mass of microbes is of similar proportions.

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  14. 14. wright496 10:49 pm 10/3/2010

    The details might have changed, but we already knew that microbes were the dominate kind of life on this planet in terms of numbers. This is exciting stuff though.

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