Coral Hotspots Found In Deepwater Canyons
September 28, 2012

Deepwater Canyons Off The Northeast US Coast, Model Helps Predict Coral Locations

Alan McStravick for - Your Universe Online

When most people think of coral reefs, they are transported to temperate waters in a tropical locale. To even locate a coral ecosystem in the cold waters of the mid and north Atlantic would be a difficult endeavor. Or, at least, one would have thought.

A recent exploration of the continental shelf and slope of the Northeastern United States has revealed coral hotspots. These are areas that have an abundance of sea life existing in a highly specialized habitat. The area explored, for the first time in decades, was right off of the coast of New Jersey and extending further north to Georges Bank, an area between Cape Cod and Nova Scotia.

“These are the first surveys in several decades for deep-sea corals and sponges in the mid-Atlantic,” said David Packer, a marine ecologist at the Northeast Fisheries Science Center (NEFSC) James J. Howard Marine Sciences Laboratory at Sandy Hook, NJ. “We previously had little or no data about some of the canyons or the available data were decades old, so what we learned in just a few weeks provided a quantum leap in our knowledge about the canyons and their habitats.”

Researchers, setting off aboard the National Oceanic and Atmospheric Administration´s (NOAA) Ship Henry B. Bigelow from July 6-18 of this year, sought out these hotspots utilizing a newly devised ℠Coral Habitat Suitability Model´, that is in current development by the NEFSC and the National Ocean Service´s Biogeography Branch.

Seeking canyons they believed were most probable in supporting these habitats, the crew explored the Toms, Middle Toms and Hendrickson canyons that are located off the coast of New Jersey. They also traveled to the Veatch and Gilbert canyons off Georges Bank. In these areas alone exists more than 70 deepwater canyons that can range in depth from as little as 330 feet all the way to more than 11,500 feet. Few of these many canyons have ever been well studied.

“The deep-sea coral and sponge habitats observed in the canyons are not like those found in shallow-water tropical reefs or deep-sea coral habitats in other regions,” said Martha Nizinski of NEFSC´s National Systematics Laboratory in Washington, DC, a zoologist and deep-sea coral specialist who served as the chief scientist on the recent research cruise aboard the NOAA ship Bigelow. “We know very little about the distribution and ecology of corals in the canyons off the Northeast coast,” she said. “Although our explorations have just begun, we´ve already increased our knowledge about these deepwater coral habitats a hundred times over.”

The research team is confident that the overall understanding of these coral habitats will serve to improve knowledge regarding deep-sea life off the Northeastern U.S. coast. They also see the information as being particularly beneficial to the New England and Mid-Atlantic fishery management councils, as it will aid their efforts to manage these exceptionally biodiverse habitats.

The July survey was part of a much larger mission whose aim and intent is to explore and map deepwater canyons and to add to the understanding and knowledge of the deep-sea corals that reside there. The Bigelow, one of 3 ships utilized by NOAA, is taking part in the Atlantic Canyons Undersea Mapping Expeditions (ACUMEN). The topography explored ranges all the way from Norfolk, Virginia to New England.

It was by using high-quality multibeam sonar maps that the NEFSC scientist and collaborative researchers were able to locate and explore the deepwater canyons of the Northeast. In addition to gaining a far better understanding of the diversity of the deep-sea coral and the sea life within that habitat, the team also sought to test the accuracy of the Habitat Suitability Model (mentioned above) at predicting the locations of deepwater corals.

To aid in documentation of the researchers finds, the crew of the Bigelow utilized ℠TowCam´, a deep-sea digital imaging system, operated by researchers from the Woods Hole Oceanographic Institution (WHOI). This allowed for photography of the sites they chose, typically between 650 and 6,500 feet in depth, helping them to confirm the accuracy of their modeling data. While no physical specimens were collected, the team was able to capture over 38,000 ℠TowCam´ images that still awaiting analysis over the coming months.

“Like the hub of a wheel with many spokes, the July Bigelow cruise was central to a project that seemed to grow over time as opportunities arose to leverage resources and use these to their fullest potential,” said Nizinski, who has studied deep-sea coral habitats off Florida, off the North Carolina coast and in the Gulf of Mexico.

“What originally started with 16 days of ship time, provided and funded by the Northeast Fisheries Science Center to explore deepwater canyons off the Northeast coast, rapidly developed into a much larger project,” Nizinski said. “What started with informal discussions between NOAA and colleagues led to a major field program that first surveyed and mapped deepwater canyons along the northeast continental shelf and slope, followed by underwater observations to verify coral occurrence. We are excited about the possibilities given the results from this first cruise.”

With the substantial increases in understanding of these deep-sea habitats, the scientists, researchers and crew are anxious to continue their study of these coral habitats that had long suffered from scientific neglect.

In addition to scientists from NEFSC and WHOI, cruise participants represented the NOS's National Centers for Coastal Ocean Science, Biogeography Branch; the NOAA Office of Ocean Exploration; the Delaware Museum of Natural History; and the NOAA Teacher at Sea program. Kathleen DeLussey, a reading specialist at the James R. Lowell Elementary School in Philadelphia, Pa., chronicled her adventures at sea on her NOAA Teacher at Sea web site and blogs.