Saturday, January 7, 2012

Scientists Set for First Expedition to Earth's Deepest Sea Vent by Andrea Mustain

A shimmer of superheated fluid gushes from an opening some 3 feet (1 meter) across near the top of a hydrothermal vent deep in the Caribbean. Researchers are returning to the intriguing site, and one of its deeper and more mysterious neighbors, to sample them for the first time.

Eat your heart out, Jules Verne: This week, a ship packed with scientists is setting out for a three-week Caribbean cruise to one of the most extreme and least explored places on Earth. It's a real-life trip that might have been ripped from the pages of the imaginative novelist's fantastical fiction. 

The 23 scientists aboard the research vessel Atlantis are embarking on a first-of-its-kind mission; their quarry lies in the perpetual night of the deep ocean, in a mysterious world powered only by the furious heat of the planet's inner workings.

Their destination appears in Google Earth as a shadowy gash in the Earth just south of the Cayman Islands.

It is the Mid-Cayman spreading ridge, a rift in the seafloor some 70 miles (110 kilometers) long and more than 9 miles (15 km) across, where geologic forces are shoving two tectonic plates apart and birthing new oceanic crust — and fueling what may be two of the most remarkable hydrothermal vent sites on Earth.

Until recently, it was thought that hydrothermal vents — essentially, seafloor chimneys that spew forth a scalding soup of chemically altered seawater — couldn't exist along the Mid-Cayman spreading ridge, also called the Mid-Cayman Rise. It is the deepest spreading ridge on Earth, plunging to nearly 20,000 feet (6,000 meters) in places, and also among the slowest moving, creeping apart at just 0.6 inches (15 millimeters) per year. Scientists thought that, at such a snail's pace, the system lacked the volcanic heat required to sustain a hydrothermal vent.

But in 2009, scientists discovered two.

One vent, the Von Damm, may offer clues to how life first arose on our planet. The other, dubbed the Piccard, lies 16,400 feet (5,000 meters) below the surface — the deepest vent ever discovered on Earth — and may prove to be the hottest. 

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