Eels swarming near deep-sea volcano startle divers

[Mr T.]

Eels swarming near deep-sea volcano startle divers

A University of Oregon researcher says it's unprecedented to see such large numbers 2,000 feet below the ocean's surface

Wednesday, May 25, 2005 RICHARD L. HILL

Scientists exploring a seafloor volcano in the South Pacific this spring were astounded to find hundreds of eels slithering nearby -- a discovery they say is unprecedented in ocean research.

Oregon marine biologist Craig Young said "Eel City," as scientists now call it, was spotted in pitch-black water 2,000 feet below the surface.

"I've never seen anything like it," said Young, a veteran of several dives to hot vents on the ocean floor. "Sometimes you'll see an eel or two at that depth, but this is very unusual.

Young, a professor and director of the University of Oregon's Institute of Marine Biology in Charleston, was co-chief scientist on an exploratory cruise in March and April to Vailulu'u, an undersea volcano off American Samoa.

He and researchers from the Scripps Institute of Oceanography and other institutions used a three-person submersible, Pisces 5, to explore the volcano, which had been discovered four years ago. On the first dive they found not only eels, but also a new volcano growing in the crater summit of Vailulu'u.

As they descended, scientists could see only about 10 feet because of the turbidity in the water caused by vigorous hydrothermal activity. They spotted the eels on fragile rock pillars surrounding the hydrothermal vent. As the sub landed, the 1-foot-long eels poured out of the pillars' caves and crevices.

It is the first known deep-sea hydrothermal community dominated by eels, Young said. The eels were found at the emerging volcano, named Nafanua after the Samoan goddess of war. It stands nearly 1,000 feet high and is 2,000 feet below the water.

Scientists are perplexed at how the eels survive in this environment. Much of Nafanua is covered with yellow mats of bacteria, which feed on chemical energy from the volcano's hydrothermal system. Vents spew super-hot, mineral-rich water that helps support a diverse community of organisms.

"The only thing that we can imagine is that they're eating these thick mats of bacteria, but we don't know of any other eels or deep-sea fishes that feed directly on these microbial mats," Young said. "It's a bit of a puzzle -- it's a very unusual kind of food chain for the deep sea."

Nafanua is similar to Wizard Island and the underwater Merriam Cone that emerged in Mount Mazama -- the home of Crater Lake -- after its massive eruption 7,700 years ago.

Hubert Staudigel, a geologist at Scripps, and Stan Hart, a geochemist at the Woods Hole Oceanographic Institution, said Nafanua is growing at least 8 inches a day. "To actually have a documented case of an underwater volcano that has emerged within an accurate period of time is very rare," Staudigel said.

Young plans to go back to the volcano in July to study the eels. He and his colleagues hope to capture a few of the animals to determine what they may be feeding on.

Staudigel and Young served as chief scientists on the recent cruise aboard the research vessel Ka'imikai O Kanaloa from the University of Hawaii. Sandra Brooke from the UO's Institute of Marine Biology also was on the research team.

Richard L. Hill: 503-221-8238; richardhill@news.oregonian.com

[John N]

Perhaps they feed off dead animals landing on the bottom a la Blue Planet dead whale eating frenzy. Might explain why they were so happy to see the sub. These particular eels might just prefer their food cooked.