SAN FRANCISCO — When the skies grow dark, what kinds of predators might rise from the ocean's depths to feed? When great white sharks interact with each other, do they follow clan-based hierarchies similar to those of wolves or lions? How are humans affecting the health of the marine ecosystem, and what can be done to conserve the ocean's resources?
Marine scientists have long yearned to answer these questions and more, but the cost of research and available technology limited their ability to do so.
Experts have estimated that up to 95% of the world's oceans remains unexplored, particularly in areas below the range of scuba divers.
"Most ocean exploration is near the shore, where it's easy to get to and shallow," said Milton Love, an associate research biologist at UC Santa Barbara's Marine Science Institute. "Once you go out in deeper water, it becomes expensive and hard. Our knowledge drops to zippo at that point."
An expedition now underway seeks to overcome those barriers, opening the way to the first systematic exploration of the nation's 12 marine sanctuaries, including the Channel Islands Marine Sanctuary.
The National Geographic Society and the National Oceanic and Atmospheric Administration are sponsoring the exploration, which was launched on April 22--Earth Day--and is funded by a $5-million grant from a San Francisco-based philanthropic group, the Richard and Rhoda Goldman Fund, and an additional $775,000 from the National Geographic Society's Exploration Council.
Over the course of the five-year project, known as the Sustainable Seas Expeditions, more than 60 researchers, including two high school teachers, will plunge into previously hard-to-reach areas, and perhaps discover new creatures along the way.
"We know more about the surface of the moon and Mars than we do about the surface of the ocean," said oceanographer Sylvia Earle, the National Geographic Society's explorer in residence.
Earle, who championed the project, hopes these expeditions will shed light on marine life and bring some of the glamour afforded space exploration down to the seas.
And where there is glamour, there is a star. Taking center stage is a one-person submersible craft created specifically for the Sustainable Seas project. An aquanaut in the 1.3-ton craft, called Deep Worker, can dive untethered as deep as 2,000 feet. The pilot uses foot pedals to control the four thrusters that maneuver the machine. The capsule is so small that a pilot can tilt the submersible by simply leaning to one side.
Pilots must meet weight requirements, which forced one candidate to shed 25 pounds before entering the program.
"What these little subs become is an extension of your body," said Bruce Robison, senior scientist at the Monterey Bay Aquarium Research Institute and one of the Deep Worker pilots. "It's like you're wearing it instead of getting in it, so all sense of claustrophobia and fear gets erased," he said.
There are other vessels than can go deeper, but researchers say Deep Worker is simpler and less costly to transport and operate, allowing up to six dives for the price of one trip in a larger manned submersible.
And although cheaper remotely operated vehicles, or ROVs, have become popular research tools, Robison said allowing a human to venture down offers many advantages.
"There is no substitute for your eyes as observation systems," he said. "When you use an ROV, it's like looking at a TV with one eye through a pipe. You never get to see the big picture."
The big picture, researchers say, is a better understanding of the life that exists offshore. One study at the Farallones Marine Sanctuary near San Francisco uses Deep Worker to obtain images of great white sharks beyond the typical scenes of frenzied feeding near the water's surface. The task is too dangerous for unprotected scuba divers. At the Monterey Bay Marine Sanctuary, Robison will observe whether animals that normally avoid visually cued predators in the daylight come up to feed at night, a phenomenon that he says could be the "largest migration on Earth."
Chris Harrold, director of conservation research at the Monterey Bay Aquarium, plans to photograph areas where treated sewage is deposited.
"This is exactly the kind of thing both the sanctuary and the general public ought to know about," he said.
Pilots will examine rockfish populations at several offshore oil platforms near the Channel Islands, building upon earlier studies led by Love at UC Santa Barbara. Love said the platforms probably serve as shelters from predators and fishing, but the number of rockfish varies from year to year. More exploration may help explain the variation. Researchers say the first year of the project will probably be spent familiarizing the newly trained aquanauts with the submersible and the surroundings in which they will work. More information will be gathered in the following years.