ABOARD the R/V TATOOSH — Meriwether Lewis and William Clark hit the brakes at the water's edge.

They had bulled through more than 3,000 miles of wilderness, cataloguing scores of plants and animals new to science, and found this same ocean. They walked on Long Beach to the south and wintered in Oregon, but the westward course of their discovery ended at the tempestuous Pacific Ocean surf.

Now, nearly two centuries later, broad, deep and dangerous waters off the Washington coast are being asked to give up their secrets in a big way as researchers probe the 3,310-square-mile Olympic Coast National Marine Sanctuary with a hot-pink autonomous underwater vehicle, sidescan sonar, submersibles and scuba gear.

They're finding a bounty.

Nutrient-rich upwellings in the summer months fuel a surge of plankton and the massive food chain it nourishes, from the larvae of crabs and barnacles to rafts of birds, fish and migrating humpback and gray whales.

In the nearshore environment, one of the most diverse on the West Coast, extensive kelp beds act as nurseries to a range of fish and invertebrates and provide foraging areas for birds and marine mammals.

"It's a perfect laboratory," said Carl Schoch, science director for the Kachemak Bay Estuarine Research Reserve in south central Alaska and head of the sanctuary's research advisory committee. "If you want to look at the intertidal marine biology or even the nearshore biology, you'd be hard-pressed to find a place that is less disturbed by people."

The Olympic mountains block convenient access to the coast. The same processes that built the mountains created a hilly, formidable coastline with few sheltered moorages, coastal roads, people, towns, vacation homes or sources of pollution.

The Olympic sanctuary is one of 13 set aside in recent decades to protect key marine resources and promote education and research. By comparison, some of the others seem like scientific boutiques.

Off Cape Hatteras, N.C., the USS Monitor, ironclad Civil War relic and the nation's first marine sanctuary, had its gun turret raised this summer as part of a $14 million salvage effort. The Monterey Bay National Marine Sanctuary south of San Francisco is home to nearly two dozen research institutes.

The Olympic Coast is more like a snarling feral cat, rarely visited and then circled warily. Try to study the area's 180 shipwrecks and you risk becoming a shipwreck. The relatively placid summer months give way in winter to huge seas that power in from thousands of miles away, hammering the rocky coast. Winds can reach hurricane-force.

Seattle-based researchers working in the sanctuary have to drive five or so hours before even getting on the water. The sanctuary's own staff, which has five or so scientists and a budget of $1.2 million, works out of Port Angeles, 80 miles from the coast.

"It's the downside of being remote," said Carol Bernthal, sanctuary superintendent. "You're remote."

Creating a safe harbor

Still, the effects of civilization have found their way into the sanctuary's waters. The Pacific maritime fur trade wiped out the local sea otters in the early 1900s, upsetting the balance of urchins, rockfish and kelp so severely that it is only now coming back into equilibrium after otters were transplanted here in 1969 and 1970.

A fear of oil and gas exploration in the late 1980s prompted then-U.S. Rep. Mike Lowry and others to push for a sanctuary, with the National Oceanic and Atmospheric Administration creating one in 1994.

"It's there for all the animals and whatever is left there to be able to survive, all the whales and the fish and the shellfish," said Chris Morganroth III, 63, a Quileute tribal historian who used to inner tube in the waters off La Push.

"I can see there's a chance for everything to remain intact for some time to come."

Bottom-fishing is still allowed in the sanctuary, but oil and gas leasing in the area are banned. Planes and helicopters are not allowed to fly below 2,000 feet because they can bother seabirds and marine mammals.

And starting next month, new International Maritime Organization guidelines will encourage large ships to avoid more of the sanctuary and give a wider berth to the coastline and the Olympic Peninsula's treacherous northwest corner at Cape Flattery.

Meanwhile, the sanctuary staff struggles to comprehend its largesse, which can go as far as 50 miles offshore and 90 miles from Cape Flattery to the Copalis River. Inside, those boundaries are three canyons, nearly a mile deep.

"We don't have detailed maps of the habitat out there," said Bernthal.

A 'day hike' on the seafloor

When researchers do get into the sanctuary, they might see the likes of big-eyed California sea lions bobbing in the swell for a peek at the Tatoosh. Or skeins of shorebirds, 20,000 and 40,000 at a time, alighting from a small archipelago of sea stacks. Or a bird flying underwater.

Three years ago, Sylvia Earle, the National Geographic Society's explorer-in-residence and the leader of Sustainable Seas Expeditions, organized several trips into the sanctuary in specially designed one-person submersibles.

Robert Steelquist, the sanctuary's education coordinator, ventured down in one of the craft and logged "a parade of creatures:" basket seastars, with curled, branching legs; sea cucumbers and lingcod and brilliant red finger sponges that looked like tiny saguaro cacti; a school of 20 or so brilliant-orange canary rockfish.

"None of the critters that I saw were unusual," he said recently. "The rocks were just rocks covered with various types of attached critters — basket stars, hydrocorals, sponges, things you'd expect to see. And yet the cumulative effect of being there, knowing that I was free and untethered, in a sense taking a short day hike at the bottom of the ocean, was exhilarating."

Last year, north of La Push, Bernthal saw a pack of transient, mammal-eating orcas descend on a herd of sea lions.

"It was kind of an interesting experience," she said. "Who are you going to root for? We all just decided to sit back and see what happens.

"They just worked this group. It was amazing to see how they communicate with each other, how they work almost like a pack of wolves. The sea lions finally figured out that they were in danger and it was like this stampede of sea lions going up on to these rocks. We think one got taken because there was definitely a lot of thrashing going on back and forth."

Since mid-September, University of Washington oceanographer Charles Eriksen has been monitoring an autonomous underwater vehicle as it records temperature, salinity, phytoplankton and other features across a 120-mile swath.

Other sanctuary research has been done by remote-operated vehicle, sidescan sonar and two-person submersible. No method, including the low-tech snorkels and tanks, is easy.

"Four hours of preparation, 45 minutes of work," Andy Palmer, the Tatoosh skipper, said recently while helping prepare for a scuba dive.

Researchers on this trip were looking for samples of sea-otter food to test for possible contaminants. They made two dives of up to 52 feet in 48-degree water, the second dive in the surging currents and cloying bull kelp by Point of the Arches. At times they swam through clouds created by millions of mysids, tiny translucent shrimp.

Surface-swimming at the end of their second dive, research coordinator Ed Bowlby saw a murre approach and dive for food, flapping its wings to fly in the water.

"It's a beautiful sight," he said.

The divers pulled up urchins of deep purple, keyhole limpets and decorator crab. Liam Antrim, resource-protection specialist, brought up a pulsating burgundy octopus.

Yes, sea otters do eat them. Bowlby has seen otters on the surface chewing one arm after another for an hour, then falling asleep with the remaining octopus body still draped across their chests.

The researchers needed more than one of each food sample so let the octopus go.

It writhed like a runaway Slinky off the stern and dropped into the uncertain shelter of the sanctuary's dark, mysterious depths.

Eric Sorensen: 206-464-8253 or esorensen@seattletimes.com. Natural Wonders appears every other Monday.