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Going Green: It came from beneath the sea
Does Marin really share its marine sanctuary with an undersea volcano?

by Joy Lanzendorfer

In the waters off Monterey, 10,000 feet below the ocean surface, is the lost world of Davidson Seamount. Down there in the darkness, pink bubblegum coral stands 8 feet tall. Spiny pink-and-white crabs scuttle across rocks. Sock tunicates bob in the current, tethered to the ground by only a string. It's a place so pristine and full of potential that it was recently made part of the Monterey Bay National Marine Sanctuary, which spans from Marin County all the way down to Hearst Castle.

Davidson Seamount is an underwater volcano about 7,500 feet tall and 26 miles long. Its summit is 4,300 feet below the surface of the ocean. It last erupted some 9 million years ago and scientists say it's unlikely it'll ever erupt again—and even if it does, the lava would stay under the water. Until recently, no one knew what was on Davidson Seamount. Then in 2002, the Monterey Bay Aquarium Research Institute sent a remotely operated vehicle down to get a closer look. It came back with stunning images of giant coral forests, brightly colored sea sponges and fish that biologists couldn't even recognize.

"The public got really excited about the images," says Andrew DeVogelaere, research director for the Monterey Bay National Marine Sanctuary. "All of a sudden, people were thinking about new frontiers and going places they hadn't been before to find spectacular new things."

While there was no immediate risk to the seamount from oil drilling or fishing, people wanted to keep it that way. In New Zealand, several seamounts had been severely damaged by trawl fishing, when fishermen drag nets along the bottom of the ocean. In November, 585 square miles around Davidson Seamount were added to the marine sanctuary, which now includes 9,100 square miles of ocean. It is the first protected seamount in U.S. waters.

Even though 99 percent of this underwater volcano is still undiscovered, it is probably the most explored seamount in the world. Only 2 to 5 percent of the ocean floor has been mapped, meaning that much of the ocean is still a mystery to us. Davidson Seamount, by contrast, was mapped back in 1933 and was the first to be called a "sea mountain." There are about 30,000 known seamounts in the world, including four in waters off the Bay Area.

"Many people look out over the ocean and think it's just a sandy bottom," says DeVogelaere. "But there are seamounts, there are canyons, there are rocks, there is sand, there are organisms that form carpets over the sand, there are fish that have never been seen before. There is a huge diversity out there under the water."

So far, researchers have identified at least 40 species on Davidson Seamount, many of which are new discoveries. There are ghost-like mollusks, sea cucumbers as red as a heart, anemones that look like Venus flytraps and yellow sponges so oddly shaped they are named after Picasso. There are white sponges that look like ruffled branches of oleander and jellyfish that float around like pink bubbles. But by far, the most prominent animals on Davidson Seamount are the corals, especially gorgonian coral, otherwise known as fan coral because it looks like giant fans. Many of the coral growing on Davidson is 8 to 9 feet tall and hundreds of years old.

"It's an exciting place to study because it's so unexplored," says Lonny Lundsten from the Monterey Bay Aquarium Research Institute, who is writing his thesis on seamounts. "I feel like one of those people in the history books exploring the Pacific for the first time."

But this is definitely 21st-century exploring. In addition to taking pictures, the unmanned vehicle has arms that can gather specimens such as corals, clams, fish and sponges for further study. While submarines have gone as deep as 37,000 feet, they are less efficient for this kind of work. Unmanned vehicles can do 12 to 16 hour days and allow scientists to work in teams instead of by themselves.

As more of the seamount is explored, more questions come up about its sea life. Why are the animals so colorful when they are living in total blackness? And why are some able to give off bioluminescence, or glow in the dark, for no apparent reason? Researchers discovered a bamboo coral, for example, that can produce bioluminescence when touched.

"We took it to the darkroom and found it has an almost electric glow when you touch it," says Lundsten. "We don't know why an animal that is catching plankton in the gulfstream would need to do that."

The diversity seems related to the current that flows across the seamount, bringing with it a steady supply of planktonic food for the sea life. The current may also be the reason there is such a variety of animals on Davidson Seamount in the first place.

"Seamounts are hot spots of biodiversity," Edward Seidel, associate curator of Monterey Bay Aquarium, wrote on the National Oceanic and Atmospheric Administration Web site after the first Davidson Seamount expedition. "Ocean currents carry larvae, like shipwrecked mariners, from various geographically distant areas. Seamounts provide a place for these lost larvae to settle and grow, so you find animals living side by side that normally are not found together."

Scientists used to think that sea life was unique to each seamount, but recent research shows that seamounts may be more related to one another than previously thought. The same animals have been found on Davidson Seamount, Pioneer Seamount near San Francisco and Rodriguez Seamount in Southern California. Scientists don't yet understand why this is, but they think it may have to do with the same current that is carrying the animals' food.

"Most likely it's the dispersal of larvae," says Lundsten. "We have a pretty strong current regime that runs the whole coast of California. These seamounts are not isolated. They are close to each other and close to the shelf."

As time goes on, Davidson may become the most studied seamount in the world. In the process, it may help us take the first steps toward understanding one of the last great mysteries on Earth—the deepest parts of the sea.

And that is every marine biologist's dream.

"For me, to go down to a place that's completely black, that never sees light and is almost freezing temperature, and to see these bright pink corals that are a foot wide and 8 feet tall at the base, and spread out like a fan, is dramatic and beautiful and inspiring," says DeVogelaere. "When young kids thinks about what they want to do when they grow up, and they think about becoming a marine biologist, this is the kind of thing they're dreaming about."