Exxon's oil slick now covers more than 3,000 square miles of Prince William Sound.

Barry Willis, a former Utahn and an outdoorsman who is now an administrator at the University of Alaska, Anchorage, knew the sound both before and after the spill. He grew up in Utah, worked for an advertising agency in Salt Lake City, earned his undergraduate and master's degrees at Utah State University, Logan, and got doctorate at the University of Indiana.Willis has spent a lot of time kayaking, fishing and exploring the sound. He developed six university programs on ecosystems and the effects of man on habitat.

If you imagine the southern shoreline of Alaska as the sole of your foot, thesound is about the highest point of the arch. This great estuary is so cut up with hundreds of bays and fjords that it has 3,600 miles of shoreline.

Willis recently flew over the immense slick. From the air it looks like this: "Depending on the sun angle, it can look like anything form a rainbow to just a black mass. It's the consistency, sort of, like lumpy chocolate pudding.

"The water's cold enough that the oil congeals. It's not what you think of when you think of a warm water spill, when you have sort of an oily sheen over the water."

Underneath, it looks like the tentacles dangling down from a jellyfish.

As it's churned by wave action, "some of it turns into tar balls, these toxic balls which just sort of float to the bottom and gradually release their toxin."

The slick has scummed 800 miles of beaches. Where waves slam it onto the rocky shore, it whips into sludge. Each high tide beats more onto the islands. In places it has built up an inch thick.

Investigators have dug sample pits on some of the sound's beaches. "In many places it's already seeped into the ground three feet or more," Willis said.

"It's not solid dirt on the soil. It's really gravel and rock ... So the oil is just migrating through the coarse gravel material."

The spill could not have happened at a worse time. In the spring, "millions of birds migrate to all parts of Alaska, and Prince William Sound is a major destination.

It happens suddenly - one day you see ducks, the next 10 or 20, the next 40 or 50. Same fro shore birds and sea birds. The numbers increase geometrically. Soon there are many thousands landing in the sludge.

Once it was a wildlife paradise. Half of Alaska's enormous salmon production came from the sound. There were humpback and killer whales in the icy blue waterand deer and brown bears on the islands.

"Otters come up -- which are real friendly little critters," Willis said. They would float on their backs beside the kayak, gobbling mollusks that they held on their chests.

Until now, 10,000 sea otters lived in Prince William Sound. "Fish and Game estimates that approximately half of that entire population will be killed."

Petroleum kills them in either of two ways. It may penetrate the natural oily material on their fur, soaking them, and they die of hypothermia. After all, it's Alaska and the water temperature is in the 30s.

"What's happening more often is the oil coats their fur, they lose buoyancy, and they sink."

They may wash up dead on the shore, and eagles feed on the oil-poisoned bodies. "On one stretch of beach in one of the islands, I think it was Knight Island,I think they found four dead bald eagles."

"Most of the animal life is pretty hungry this time of the year, he said. "The deer come down at low tide and feed on the seaweed. The seaweed is contaminated and the deer die."

Brown bears, - the huge Alaskan variety of grizzlies - are starting to come out of hibernation. "They eat all sorts of strange things," he said. "They're very hungry when they come out ... the first thing they feed on is carrion."

If the thousands of dead and dying birds are not gathered quickly, eagles andfoxes and bears will eat them and die also.

The spill is destroying the entire food chain, from algae, plankton and mollusks, to otters and eagles.

For millions of years, Prince William Sound was one of the world's most pristine natural areas. Now, it has become a sea of death.