HALIFAX — Scientists got a glimpse of a mysterious corner of the undersea world off Canada's East Coast, discovering new species and peering for the first time into little-known ecosystems that are home to rare corals and fish.

A team of about 20 Canadian researchers probed the waters off Nova Scotia and Newfoundland in a bid to find out what's far beneath the water's surface and better understand how the ecosystem works.

The group, which was to release its findings Monday, used a remotely operated submersible to capture images of four areas along the continental slope off Nova Scotia. They were able to instantly beam back pictures of bright white and pink corals, a new variety of starfish and a silvery octopus named Dumbo, among other rare finds.

"It was amazing," Ellen Kenchington, a research scientist at the Bedford Institute of Oceanography in Halifax, said in an interview.

"You're looking at something down there, there's no light, it's so deep and you know no human eyes have ever seen these things before, and it's almost like you feel like you're the first man on the moon."

The submersible hovered over the craggy bottom of a protected area near Sable Island known as the Gully, the largest submarine canyon in eastern North America.

Previous studies have been done on the area but provided information on life forms down to only 500 metres, far less than the 2.5 kilometres that Kenchington and her team reached with the underwater vehicle.

One of the most important discoveries was a type of xenophyophore, a single-cell animal the size of a grapefruit that had previously been found only in the deepest part of mid-Atlantic.

"It's a really unusual thing to find and is a new record for the area and, as far as I know, for Canada," she said as she returned from the three-week expedition aboard the Canadian Coast Guard vessel Hudson.

The scientists, from the federal Fisheries Department and various universities, collected more than 3,000 digital images, hundreds of hours of video and dozens of live samples.

Much of it will be used to create a record of what's in the area, which can be used to measure the effects of climate change, fishing or oil and gas activity.

"It's really important that we document where they live, how much damage is done and what kinds of recovery times are involved," she said.

They know, for example, that northern bottlenose whales congregate there, but it's not clear what they feed on.

"So what I'm looking at is not just what species are there, but how do they function, what is their role in the ecosystem," she said.

"We want to see how they link together so we can anticipate the kinds of effects changes in water temperature would affect the whole system."

The researchers also discovered a colony of lophelia, a stony white coral that forms large reef frameworks providing a home for many other animals. The coral had been sighted in other areas off Cape Breton, but hadn't been seen before in the Gully.

Kenchington said the team also recorded another new species of bubblegum coral, a spindly pink species that is the largest sea-floor invertebrate in the world.

The survey, which cost the department about $500,000, also provided images of a rugged landscape of 200-metre cliffs that shot up from the ocean floor at 90-degree angles, creating little pyramids for large fish to weave around.

In areas around the Grand Banks, they saw extensive evidence of the effects of bottom trawling. The floor was swept clean and large rocks were overturned by the big nets that drag across the bottom scooping up fish and virtually everything else in their path.

Kenchington said that will be part of the information they take to fisheries managers to determine what marine areas should be closed off and protected.