Remarkable diversity of life found in sea canyons off Northeast coast
The deep-sea canyons off the Northeast coast of the US are largely unexplored. A 36-day expedition currently under way is finding a rich trove of marine life.
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Energy resources also are on the agenda. During the first of two legs of this summer's expedition, researchers spotted the northernmost undersea methane seep yet discovered along the eastern seaboard – complete with communities of marine organisms that feed off the methane. Not only was methane bubbling out of the sea floor, but the surface sediments on the flood held ice-like mixtures of methane and water mixtures, known as methane clathrates, frozen by the combination of frigid undersea temperatures and the enormous pressure on the sea floor.Skip to next paragraph
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The expedition is using NOAA's research ship Okeanos Explorer and the agency's newest remotely-operated undersea vehicle, the Deep Discoverer. This is Deep Discoverer's maiden expedition after clearing its engineering trials in May.
Dozens of researchers in the US and France are participating via telecommunications links that allow them to see what the undersea rover is seeing as it takes its images, share insights into what the images may be revealing, and plan next steps for the mission. The approach allows more researchers to play an active role in the expedition than would be the case if the participants were limited to the relatively sparse bunk space on a research ship.
Going in to this expedition, Texas A&M University researcher Brendan Roark says he was not a big believer in such "telepresence" cruises. "But ultimately, it was fantastic because I learned a lot more by having conversations with anywhere from 15 to 30 scientists," he says.
Even before the expedition's end Aug. 16, he and other members of the team have marveled at the some of the unique views they've been given of these little seen and poorly understood environments.
One of the key features reef systems in these canyons seem to share is remarkable longevity. Biological processes work more slowly at 1,000 meters than they do at the surface. Deep-sea corals in canyons can live for as many as 4,500 years.
They represent potentially rich archives of information on past climate and ocean conditions in the region, says Dr. Roark.
But once destroyed, the reef communities may take decades to centuries to recover. Little is known about that process because, until now, the deep-sea reefs researchers have seen have been mature ones.
"On the second day of this cruise, we found an area that has some recent slumping, a landslide, and we saw a lot of different coral species that were very small. We haven't seen that before," says Shank. "Many, many were there and they were all six to eight inches tall. That tells us that these are relatively new."
How new, no one knows because so little is known about the growth rates and life cycles of these species, he says.
The canyons the team has explored so far have been remarkable for the diversity and amount of new life, says Andrea Quattrini, a PhD candidate in marine science at Temple University in Philadelphia and one of the expedition's lead scientists.
In addition to the new corals, "we saw several octopus guarding eggs, in one case a sponge with bobtail squid eggs – in one case we saw one hatch," she says. And in many of the canyons the Deep Discoverer sent back images showing deposits of catshark and skate eggs.
"I was surprised at the amount of new life being formed," she says.
Researchers also noted with some amazement the presence of crabs the size of quarters occupying small bottle-brush-like coral. They are unique to the coral, typically appear in male-female pairs, and some have a juvenile as well.
"It's like a family unit," says Shank of the species. A couple's hunt for a coral to occupy can be like hunting for a specific lamppost out of all the lampposts in Manhattan. "Somehow they get there, a male and a female, and they produce offspring. It's just amazing that life is sustained and maintained in this way."
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