James Cameron dive launches race to the bottom of the world (+video)
Before James Cameron made a solo dive to the Challenger Deep – the deepest point in the ocean – only one mission had been there before. Now, several groups are planning deep-sea dives, and engineering advances could shed new light on the region.
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Although deep-sea trenches make up only about 1 percent of the sea floor, they are of keen scientific interest. They form as old, dense oceanic crust, long ago made by lava welling up along mid-ocean volcanic ridges, now is pushed beneath more-buoyant continental crust.Skip to next paragraph
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The process creates a long, canyon-like boundary. The Mariana Trench, for instance, has an average width of about 43 miles but narrows to a slot-like valley at the bottom, nearly 7 miles below the ocean surface.
With crushing water pressure – roughly 1,000 times air pressure at sea level – and temperatures hovering around freezing, the environment at the bottom of these trenches is home to an unusual assortment of creatures. Last summer, for instance, a team from the Scripps Institution of Oceanography in La Jolla, Calif., and the National Geographic Society found that a super amoeba – a single-cell organism measuring about 4 inches across – was inhabiting depths two miles deeper than previously believed.
The creatures, known as xenophyphores, also host a range of other, multicelled organisms.
Samples of trench communities have turned up a range of more complex creatures, including shrimp, fish, and soft-shelled snails uniquely adapted to their harsh home.
The sea floor Cameron saw, however, was barren, he told reporters. He said never reached a place that looked to host any interesting biology.
For the creatures that do live in the deep, researchers are trying to figure out where they get their food, as well as the pecking order in the food chain at such depths.
The region also is of interest to astrobiologists as they explore approaches to detecting and studying life on other planets or moons. Jupiter's moon Europa and Saturn's moon Enceladus are thought to have small oceans under their icy crusts. Any future mission to explore those oceans would require some kind of sensor package sent into the depths.
And there's plenty of ocean exploration to do on Earth, notes Bob Gagosian, president of the Consortium for Ocean Leadership, a nonprofit organization in Washington that focuses on building support for ocean research and ocean policy.
Despite some 200 years of oceanography, scientists have explored a scant 5 percent of the planet's oceans, he says. For him, Cameron's dive is significant for the spotlight the filmmaker's efforts are throwing on ocean exploration and for the technology the Deepsea Challenger exhibits – in particular the stunning speed of descent and ascent.
Contrasting the Deepsea Challenger with Alvin, the iconic three-person submersible operated by the Woods Hole Oceanographic Institution in Woods Hole, Mass., Dr. Gagosian notes: Cameron “got down there at about 11,000 meters in the same amount of time it takes Alvin to get down to 3,500 meters.”
Alvin is undergoing a refit that will substantially increase its operating depth, although not enough to enable it to reach the Challenger Deep.
But the design approaches used by Cameron's team and others, if proven robust enough, could be applied to a new range of manned and unmanned vehicles, Gagosian says. Speeding ascent and descent means spending more of a voyage's expensive ship time on the bottom gathering samples and images, rather than in the commute to and from the ship.