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Thursday, Dec. 20, 2001
Extra-terrestrial squid seen in the abyss
By ROWAN HOOPER
The world's largest ecosystem? Not the Amazon rain forest, nor the Great Barrier Reef. It is the abyss.
Far below the depth that light can penetrate the oceans is the abyssal zone, which starts at 2,000 meters. The pressure is huge -- hundreds of times that at the surface -- and its volume is immense (after all, oceans cover more than two-thirds of the Earth's surface). Until 1977 it was thought that nothing lived at those depths that did not feed on material falling from higher up, where the Sun's energy powered life.
But things do inhabit the abyss -- and some are more alien than anything seen on "The X Files."
Evidence of one of the most startling -- a giant squid, 7 meters long and hitherto unknown -- is published today in the journal Science. Its arms, all 10 of them, are longer than those of any known squid species, and are held in a unique, ghostly position, reaching out horizontally before trailing down.
"That such a substantial animal is common in the world's largest ecosystem," the researchers write, "yet has not been previously captured or observed, is an indication of how little is known about life in the deep ocean."
That situation is slowly changing, as biologists, geologists and even NASA astrobiologists wake up to the possibilities of life in the deep sea. New species are being discovered almost every time someone sends a submersible down.
Michael Vecchione, of the National Marine Fisheries Service in the National Museum of Natural History, Washington, D.C., headed an international group of marine biologists who have filmed the mysterious squid all over the world, in the Atlantic, Pacific and Indian oceans. Suckers could be seen on the squid's arms.
"I guess that it feeds by spreading long, sticky arms to entrap passing prey, somewhat like a spider web catches insects," Vecchione said in an e-mail interview.
Light only reaches to about 600 meters, but the squid were encountered deep in the abyssal zone. Life can exist down there, independent of the Sun, because of an independent energy source: hydrothermal vents. As plants on the surface convert the Sun's light into energy by photosynthesis, so organisms around deep-sea vents generate energy by oxidizing hydrogen sulfide by chemosynthesis. That was the breakthrough discovery made in 1977, when geologists used a submarine to explore fault lines on the sea bed of the Galapagos.
The geologists were hoping to see evidence of volcanic activity, and they did. What they didn't expect to find was life. There was an entire community of organisms crowded around the vents: giant clams, mussels, blind white crabs, anemones, fish, giant tubeworms and eyeless shrimps.
But it didn't just look like an alien world. Some of the microbes down there were, in effect, alien. They contained genes not seen in any other known lifeform, and a new category in the basic divisions of life had to be created: the Archaea.
Some scientists are also suggesting that life on Earth started in thermal vents. That's why NASA's astrobiologists are also excited about life in the abyss. NASA's space probe, Galileo, last flew past one of Jupiter's moons, Europa, and took measurements that suggested the presence of an ocean beneath the frozen surface. Europa is so far from the Sun that its surface is a bitterly cold minus 200 degrees -- but it may have a warm, liquid core like Earth. And if life can exist on Earth independent of the Sun, there is no reason why it can't also exist on Europa.
"The most important point about this research is that it points out how little we know about the [by far] largest ecosystem on Earth," said Vecchione. "Most of this world is a 'new world' yet to be explored. Most of the living space on Earth is the deep, open waters -- about which we know the least."
Dhugal Lindsay, of the Japan Marine Science and Technology Center in Yokosuka, Kanagawa Prefecture, one of the authors of the Science paper, adds: "But just because we know little about the deeper depths doesn't necessarily mean we know what is going on in the upper 1,000 meters -- in fact we don't."
Lindsay saw and filmed the newly discovered squid species during a 2,300-meter dive in the Indian Ocean, in Japan's high-tech submersible Shinkai 6500.
"We don't really know what else is down there," he said. "I saw bioluminescent sharks a little higher up, and a 1.8-meter long-eared octopus at around the same depth as the squid. That was only the fourth or fifth specimen ever observed, so there could really be anything down there."
The waters around Japan are also being searched, budgetary constraints permitting. "The area east of Chichijima and Hahajima, where the giant squid Architeuthis is often found fresh in the stomachs of sperm whales, would be the ideal place to start looking," Lindsay said.
The Japan Marine Science and Technology Center Web site, in English and Japanese, is at www.jamspec.go.jp E-mail Rowan Hooper at email@example.com