Norfolk Canyon yields deep-sea coral surprises

Norfolk Canyon, in particular, held two surprises

NEWPORT NEWS, Va. (AP) — About 80 miles off the Virginia coast, the Continental Shelf drops off from a depth of 600 feet to sink thousands of feet more toward the black bottom of the deep ocean.

The shelf stretches north to Canada, and carved all along its slope are great undersea canyons — some 100 miles or longer, and deeper than the Grand Canyon. Twilight worlds that scientists say have gone largely unexplored, unappreciated and misunderstood.

But from 2011 to 2014, a series of expeditions into some of those canyons using submersibles and special cameras unveiled a surprising landscape of vibrant, colorful coral forests, sponges and strange creatures thriving in the cold and dark miles underwater.

“A lot of people think of corals as being warm-water, shallow-water things,” said Michael Vecchione, a deep-sea expert at the Virginia Institute of Marine Science (VIMS) in Gloucester Point. “But there are a lot of coralsliving in deep water. We knew that there were some corals like this, but what we didn’t know is that it’s really common for very large aggregations of them to be found in places like canyons.”

Unlike their tropical cousins, such corals don’t need sunlight to grow abundantly and in bright hues. In fact, some even emit their own bioluminescence.

“I was really surprised the first time I saw that,” Vecchione said. “Some of the deep-water corals will light up when you touch them.”

If that sounds like something out of the sci-fi movie “Avatar,” that may be no coincidence — director James Cameron is an avid deep-sea buff.

Vecchione was one of the scientists tapped to watch live feeds from the remotely operated vehicles, or ROVs, that launched from the Okeanos Explorer, the science vessel of the National Oceanic and Atmospheric Administration (NOAA), which led the expeditions. Last spring, he also had his students at VIMS watch the camera feeds in real time.

While man has been exploring the deep sea for a century, he said, our knowledge was extremely limited or in some cases flat-out wrong. The expeditions helped confirm that.

“When people first started exploring, they thought nothing could live in the deep sea,” Vecchione said. “And as they realized that things can live in the deep sea, the idea was there wasn’t very much — that the deeper you went, the less there was and the diversity was not very high. It turns out all of that is not true.

“There are places with a very high abundance of things. There were completely unexpected types of organisms discovered. So the more we explore our own planet, the more we understand that the deep sea is a really important part of life on Earth.”

Deep-sea corals and associated species such as sponges and anemones form a vital habitat for the creatures that live on them outright or rely on them for nurseries, refuge or food.

Several years ago when the federal government considered opening up blocks of the Atlantic to energy exploration, it had to find out first if there were vulnerable coral habitats that needed protecting. So the expeditions were launched under a funding partnership between NOAA, the Bureau of Ocean Energy Management, NOAA’s Office of Ocean Exploration and Research and the U.S. Geological Survey.

Sandra Brooke at the Florida State University Coastal and Marine Lab was part of the team exploring Norfolk Canyon, just off the Virginia coast, in 2012 and 2013.

As Brooke describes it, Norfolk Canyon is a gouge in the side of the Continental Slope, with a sharp point at the head and steep walls. As it stretches down about 12 miles, it fans out at the base. Like other deep-sea coral canyons, there’s a strong current feeding through, bringing in essential nutrients for creatures that live there and sweeping the substrate clear of sediment.

Until the expeditions, she said, only 146 coral records existed for the entire Mid-Atlantic Bight, or the coastal region from Massachusetts to North Carolina. But from the 26 ROV dives alone that her team made in Norfolkand Baltimore canyons, they retrieved 2,100 coral records.

“That gives you an idea of how little we know about coral distributions in those canyons,” Brooke said in a phone interview from her office in Florida. “Or did, before the expedition. The other thing that we found is there’s a lot more out there than we thought.”

Norfolk Canyon, in particular, held two surprises.

First was finding stony coral there and in nearby Baltimore Canyon — until then, it had never been spotted in the middle of the night before.

It was, Brooke said, a “really cool thing, from my perspective.”

The other was finding a cold seep at its base — only the third discovered in the western Atlantic, she said, besides two off the coast of North Carolina.

A cold seep, or cold vent, is an area where methane and sulfides bubble out of the ocean floor, providing nutrients for animals that live in such environments.

The one at Norfolk Canyon was surprising not only because it was there, but because of its size.

“It was absolutely massive, at 1600 meters’ depth,” Brooke said. “It’s probably the biggest one in the North Atlantic, and nobody knew it was there, 70 miles off the coast of one of the busiest metropolitan areas in the U.S.”

Zoologist Martha Nizinski said she and her colleagues will continue to build on the science, and have “already increased what we’ve known exponentially.”

A VIMS graduate, Nizinski now works with NOAA’s National Marine Fisheries Service and was chief scientist of the deep-sea coral program in the Northeast.

Part of what makes these corals so vulnerable, she said, is they’re so slow-growing that any disturbance could be devastating. But if kept tucked away safe in their canyons, they could rival Methuselah.

“Some of the research has shown some of these coral species they tried to age are thousands of years old,” Nizinski said. “And we don’t understand completely their recruitment, so if the habitats are disturbed, we don’t know how long it’s going to take — if ever — for these habitats to come back.”

On Feb. 11, the Mid-Atlantic Fishery Management Council is expected to vote on a proposal to protect deep-sea corals from human activity, including commercial fishing.

“Deep-sea trawling is the biggest threat to deep-sea corals, period,” said Brooke.

For the most part, though, it isn’t on purpose — fishermen don’t want to get their gear torn or tangled up on rough habitats.

“The fishermen don’t want to be there any more than we want them there,” Brooke said. “But there are times when the weather blows them off or they mess up. There are accidents. So those corals are left vulnerable.”

The council is considering a range of options to help avoid interactions, she said, from closing off discrete zones known to contain corals to restricting fishing in broader zones based on ocean depth.

Comments are closed.