Strange Worms That Live on Whale Bones Discovered

WASHINGTON (AP) - Two strange new species of worms, without eyes or stomachs or even mouths, have been discovered living on the bones of dead whales in California's Monterey Bay. "Who knows what we can learn here," researcher Robert Vrijenhoek said. "There are many things left to discover in this world. Some we find by accident ... and some we find because we look in places that few people have explored before, as in much of our work in the deep oceans."

In this case, it was a bit of both because the unexpected discovery was made about 9,400 feet below the surface.

Lead researcher Greg Rouse of the South Australian Museum added: "Deep-sea exploration continues to reveal biological novelties" such as this "remarkable" worm.

Vrijenhoek, of the Monterey Bay Aquarium Research Institute in Moss Landing, Calif., said the worms, ranging from 1-inch to 2 1/2-inches long, have colorful, feathery plumes that serve as gills and green "roots" that work their way into the bones of dead whales. Bacteria living in the worms digest the fats and oils in the whalebone.

The researchers named the worms, a new genus, Osedax, which is Latin for bone eating. Their findings are reported in Friday's issue of the journal Science.

"The worms provide insight into the cycling of carbon that reaches the bottom of the ocean. A dead whale delivers the equivalent of 2000 years of 'marine snow' drifting to the bottom ... where carbon is fixed into organic molecules," Vrijenhoek said. Marine snow is made up of bits of dead fish and other matter than settle to the floor of the sea, feeding many creatures there.

He added that the "worms turn whalebone lipids (fats) into worm eggs and larvae that are carried away from the carcass to produce new worms or to be eaten and dispersed by other animals. This discovery adds to the limited knowledge we have about what happens to organic carbon on the bottom of the ocean."

"Initially we were puzzled why every worm was a female," Vrijenhoek said in a telephone interview. He said Rouse took some worms to his laboratory for study and discovered tiny male worms living inside the females.

The males still contained bits of yolk, as if they had never developed past their larval stage, but they also contained large amounts of sperm.

The female worms, regardless of size, were full of eggs, the researchers noted....

"These worms appear to be the ecological equivalent of dandelions - a weedy species that grows rapidly, makes lots of eggs, and disperses far and wide," Vrijenhoek said.

He said a whale carcass may last for decades before it is fully consumed. The carcasses, termed whale fall, tend to be found along migration routes so that eggs dispersed from one whale-eating worm may find another carcass nearby.

At first the researchers - who were actually studying clam ecology - were at a loss to determine what kind of creature they had found.

"They have no mouth, no guts, no obvious segments like all worms are supposed to have," Vrijenhoek said. They looked a lot like little miniature versions" of the strange worms discovered living around hydrothermal vents in the oceans. These vents are cracks in the ocean floor where very hot, mineral-rich water bubbles out from the earth's crust.

So the team extracted DNA from the new worms and discovered they were indeed related to the giant vent worms.The vent worms have colonies of bacteria allowing them to live off sulfides released from the vents, while the new worms have bacteria that digest fats from bones.

The new whalebone worms were divided into two species, and the researchers concluded that the most recent common ancestor lived roughly 42 million years ago, about the same time whales themselves first evolved.

The scientists named the two species of Osedax "rubiplumus" for their red feathery gills and "frankpressi" in honor of Frank Press, a former president of the National Academy of Sciences who recently retired from the board of the Research Institute.

They found the worms with a remotely operated submarine, which discovered the whale carcass.

The jaw was covered with a "beautiful red carpet" Vrijenhoek recalled. That wasn't surprising because many marine worms are red, he said, but when they got the bones to the surface they knew immediately they were dealing with something totally different.

The research was funded by the David and Lucille Packard Foundation, the National Science Foundation and the South Australian Museum.

Nature Magazine has an article on this: Bone-devouring worms discovered. I was going to post it as a new thread when I found this pre-existing thread. Here's the article:

Deep-sea species may have completely new form of metabolism.

Two worm species discovered in the dark recesses of the deep sea could rival the macabre beasts of your childhood nightmares. Scientists have named a new genus, Osedax, which is Latin for "bone devourer", for worms that thrive by excavating the bones of fallen whale carcasses.

The worms contain bacteria that help them digest the fats and oils of the whale skeletons. This type of symbiotic relationship has never been seen before, and may represent a completely new type of metabolism.

Researchers from the Monterey Bay Aquarium Research Institute (MBARI) in Moss Landing, California, discovered a whale skeleton that was "carpeted with worms" while searching for clam beds in the trough of Monterey Canyon, some 3,000 metres deep.

But the worms were like nothing they had ever seen before. The females - roughly the thickness of a pencil and a few centimetres in length - lack eyes, mouths or stomachs. Instead they consist of a balloon-like egg sac, which branches into a greenish root system.

These branching roots grow into the whalebone to extract fats and oils from the marrow. Symbiotic bacteria that live inside the roots break down the lipids, but how nutrients are transferred from the bones to the bacteria and then to the worms is not yet known.

Radical metabolism

Scientists have been studying "whale falls" - areas where fallen whalebones have concentrated along the migratory paths of whales - for the past 15 years. But until now, all the organisms found at whale falls have used 'chemotrophic' bacteria to help them capture energy from the sulphide-rich swamps that build up around whalebones. This is the same type of metabolism used by species found at hydrothermal vents. These animals use bacteria to gain nutrition from the sulphide- and methane-enriched waters resulting from volcanic activity at the sea floor.

The new worms are the first animals known to exploit bacteria that break down lipids - akin to the bacteria found in oil seeps.

"It is one of the most novel uses of bacteria by invertebrates that we've seen to date," says Shana Goffredi, a marine biologist from MBARI, one of the researchers who reports the find in Science this week1. "It has driven the evolution of this animal. The worm has modified its body in order to accommodate the symbionts," she says.

Distant relative

Scientists were at a loss to identify the worms based on their strange anatomy, but analysis of their DNA has revealed that the worms are distant relatives of the giant tubeworms that characterize hydrothermal-vent communities. The researchers determined that the two new species diverged about 42 million years ago, which is about the same time that many whale species first arose.

"The implication is that these worms were doing this job on other whale bones quite some time ago," says Bob Vrijenhoek, an evolutionary biologist from MBARI who is one of the authors on the paper. "This is not some recent invention."

Sperm factories

There were more surprises to come. The researchers have also found that whereas female worms are several inches in length, males are little more than microscopic threads, which seem to act as nothing more than sperm factories. A female worm can sweep up to 100 males at once into her egg sac, where fertilization occurs.

The researchers speculate that the sex a larva develops into is determined when it first lands on a surface, after floating around in the water. If the larva encounters a clear patch of whalebone, it becomes a female. But if there is no place for the larva to land except on another female, it does the next best thing and becomes a male, to provide that female with sperm.

A larger photo with caption:

This female worm, from the newly designated species Osedax frankpressi, has been dissected in the whale bone. The green tissue is where bacteria are found, and part of it has been torn, exposing the white ovary. A reddish "palp" captures oxygen for the worms and the bacteria.

Some more pic's:

Laboratory photo of one of the newly discovered bone-eating worms, Osedax frankpressi, which has been removed from a whale bone. Normally only the red and white plumes and the pinkish trunk would be visible. The greenish roots and whitish ovary would be hidden inside the bone.

A whale bone covered with O. frankpressi worms being collected by the manipulator arm on MBARI's remotely operated vehicle Tiburon at a depth of almost three kilometers in Monterey Canyon.

Photomontage of the whale fall in Monterey Canyon, as it appeared in February 2002, soon after its discovery. Note the large numbers of red worms carpeting its body. The small pink animals in the foreground are scavenging sea cucumbers.

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