"A normal hydrothermal vent might produce something like 500 megawatts, while this is producing 100,000 megawatts. It's like an atom bomb down there."
Recent studies have attempted to factor the heat from the world's known hydrothermal ridges into ocean circulation models.
"Some studies estimate that for the Pacific, background thermal heating might increase ocean circulation by up to 50 percent," Murton said.
Regular hydrothermal fields stir the water for only a few hundred meters (about a thousand feet) above the ocean floor. "But these megaplumes can reach a column of 1,000 to 1,500 meters [3,280 to 4,920 feet], so it reaches right up into the midwater," he said.
But even the Indian Ocean megaplume may be small compared to larger underwater eruptions that have as yet gone undetected.
"At the moment those that we've seen have come from small eruptions in the larger scheme of things," he said.
"But we know when we look at the ocean floor that there have been much larger eruptions, so we can only speculate about what magnitude of event plumes would come from those."
The new data on hydrothermal fields and megaplumes underscores the fact that volcanic activity on the ocean floor remains a largely mysterious phenomenon.
"Ninety percent of the Earth's volcanic activity takes place underwater," Murton said. "Just because we can't see it doesn't mean it's not there."
In addition to their potential impacts on ocean systems, hydrothermal vents provide scientists with a tectonic window below the planet's surface.
The vents essentially form open rifts in the crust that allow chilled water to enter and cool the Earth's interioroffering scientists a peek at the geology inside.
Researchers at the AGU meeting reported on the state of current research to uncover the vents' scientific secrets.
They have determined, for example, that the vents are hotspots for precious metals, such as silver, gold, zinc, and copper.
As yet, these resources lie beyond the reach of commercial interests because mining the ocean floor strains the bottom line.
"The cost of working in the deep ocean is so extreme," explained Reves-Sohn of Woods Hole. "We have the same problem in the scientific community. We don't get to go to look at these places as much as we'd like."
Although active deep-sea hot springs haven't yielded their precious metals to humans, they have surrendered living resources that could prove more valuable.
"The oceans are a chemical soup," said Peter Rona, a marine geologist at the Institute of Marine and Coastal Sciences at Rutgers, the State University of New Jersey.
"And the global diversity of these hot springs reported in these [AGU] sessions adds different chemical ingredients to that soup."
One of these ingredients is the heat-tolerant microbes that provide the base for the vents' ecosystemsconverting chemical energy much as plants convert sunlight during photosynthesis.
"To everybody's surprise it is the microbes that live in these vents that are being used first [in commercial applications]," said Rona, who studies the microbes with support from the National Science Foundation and NOAA.
"There are compounds in the microbes that are already being used for industrial and medical applications. Compound enzymes used in detergents, food preservatives, [and] DNA 'fingerprinting' for both research and forensic purposes."
"Also, compounds are being tested by NIH for cancer treatment and other health applications," Rona added. "And it's just the dawn of exploration of these deep sea vents."
Free E-Mail News Updates
Sign up for our Inside National Geographic newsletter. Every two weeks we'll send you our top stories and pictures (see sample).
SOURCES AND RELATED WEB SITES