Scientists have discovered a forest of deep-sea coral in the Gulf of Maine, the first time that such an abundance and diversity of coral has been found in the gulf waters.

Scientists have long known that coral exists in the cold Gulf of Maine waters, and fishermen occasionally snag pieces in fishing nets. But the discovery of vast amounts of purple, pink, orange and yellow sea fans 50 miles off Mount Desert Island offers a new dimension of the ocean bottom that could only be imagined before.

“It’s just completely remarkable,” said Les Watling, a professor of oceanography at the University of Maine’s Darling Marine Center in Walpole. “We had no idea that in cold water you could get sea fans at this density. I mean, no one else has ever seen anything like this, except maybe up in Alaska, but certainly not in the Atlantic.”

Watling and his colleagues began searching for corals last year, using a submarine and clues from offshore lobster fishermen about where they should look. They searched two canyons off Georges Bank and found one coral bed more than 3,000 feet down before Hurricane Erin kicked up the seas and they had to quit.

This summer they used a remotely operated vehicle, or ROV, and searched an 800-foot-deep area known as Jordan Basin, as well as another area five miles southwest of Mount Desert Rock. The project is funded by the National Undersea Research Program.

Watling said the terrain was so rough at one spot off Mount Desert Rock, “if it was out of the water there would be some real technical rock climbing. It’s straight up and down with these ledges hanging outward. And the corals were hanging upside down in those places, sort of like a curtain.”

They also found 3-foot-high coral trees, some of which could be two or three centuries old. But there was only one species there, compared with at least six to eight species in Jordan Basin.

“This place in Jordan Basin has some of the bigger trees. But a lot of them are small fans that are about a foot high, and there’s thousands of them,” Watling said. “Literally, the rock surface is covered.”

Many of the corals looked like sea fans a tourist might encounter while snorkeling in the Caribbean, but their branches were thicker and less numerous, Watling said.

Their colors were similar to those found in tropical waters, but more muted.

“You get pinks, but they’re like a very delicate, light pink,” Watling said. “The orange ones are really orange, they stand right out and yell at you, ‘I’m orange.’ And some of the yellows are more of a golden yellow than a true yellow. The purples have a bluish tinge, and they’re a dull purple, not a bright purple.”

The researchers also believe they may have turned up two new species of coral, including one that’s similar to an Antarctic species.

That is not too surprising, considering how much unexplored territory there is left in the ocean, said Kevin Eckelbarger, director of the Darling center and one of the investigators on the project.

He said there are probably many species yet to be discovered because there are so few people in the world looking for deep-sea corals.

“If you look at the vast areas of the ocean that are accessible only by submarine, and by minisubmarines at that, we have hardly touched the surface,” Eckelbarger said.