Most people associate reef systems with tropical islands and warm, shallow waters.
However, those are coral reefs—reefs made of living creatures.
Believe it or not, there are two unique reef systems off the North Carolina coast. They are made of rock but they are still reefs, and while they aren't made of ocean life, they are covered with it.
The first system is found primarily on the edge of the continental shelf, about 75 miles offshore. There are smaller systems rising periodically from the ocean floor about 40 miles off the coast as well.
Together, they all make up the Outer Shelf Reefs. The rocky reefs are not continuous: some are small outcroppings, others cover large areas. Some are flat, some tower 30 or more feet above the ocean floor. The reefs are found in water that is 40-100 feet deep. Each reef is different, but they are all amazingly diverse islands of life.
While the reefs themselves are dark gray, the living creatures on and around the reefs are brightly colored. The reefs are dark islands in a sea of sand. Avery Paxton, marine ecologist and Ph.D. candidate with the UNC Institute of Marine Sciences, says she and other researchers have already discovered that the reefs serve as a nursery for a variety of fish species, many of which are vital for the state’s commercial and recreational fishing industry.
The reefs serve as oases for fish and invertebrates in the otherwise barren ocean floor, providing protection from predators as well as food resources. Juvenile fish live on the reefs closer to shore and as the fish mature they move offshore into deeper waters.
The second reef system is found much further offshore—between 50-100 miles out.
This system is known as the Lophelia Coral Banks, named after the coral species that makes up the reef system. But while the Outer Shelf Reefs are located all along the coast, the Lophelia Coral Banks are found off Cape Lookout. They may be the northernmost deep-water coral banks along the east coast.
Because the water is deep, the reefs are difficult to explore, so not much is known about them. Scientists have used submersibles to gain some information, and it appears the coral banks are populated by a combination of deep-water reef fish, as well as fish from midwater and deep ocean areas. Researchers from the National Oceanic and Atmospheric Administration (NOAA) are surprised to find that fish seem to constantly migrate between the upper ocean and this deep-sea reef community.
In addition to the natural reefs, the North Carolina Division of Marine Fisheries maintains 42 ocean artificial reefs between a ½ mile to 38 miles offshore, primarily to create new sport fishing grounds.
No matter how deep the ocean is where the reef is located, studying the underwater landscape is difficult. But researchers are diving deeper with their tools and technology to learn about reef systems and the fish that inhabit them. Scientists hope that growing database of knowledge will help ensure the future of life on the reef.
Frank Graff is a producer/reporter with UNC-TV, focusing on North Carolina Science Now, a weekly science series that airs Wednesdays, beginning in August 2013, as part of North Carolina Now on UNC-TV. In addition to producing these special segments, Frank will provide additional information related to his stories through this North Carolina Science Now Reporter's Blog!
- Video: Seismic Fish