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Learn more about these OCEAN and COASTAL RESEARCH areas...


Ocean Exploration and Undersea Research

Deep-sea Corals

NOAA, through its Fisheries, Ocean, and Research offices has recently ramped up a major program on deep-sea coral research. This research has a foundation spanning more than a century ago with the author Jules Verne who described an underwater forest "composed of large treelike plants....with branches of a shape I have never seen before" in his book 20,000 Leagues Under the Sea. For at least 200 years people who have fished have reported lines becoming entangled in deep-sea trees. These so called trees are thickets of corals that provide essential fish habitat for fish and other marine life. Unlike the shallow tropical coral reefs these corals are found in dark frigid waters often beyond the continental shelf break in many of the world's oceans.

Why are deep-sea corals important?
Only in the past two decades has there been an increase in the concern and study of these corals because their importance was not generally recognized nationally and internationally. These deep-sea trees of the seas can be thousands of years old and have been found at depths ranging from 150 to 3,000 feet although some species range to 20,000 feet. These corals, unlike the shallow water species, do not require symbiotic organisms and sunlight to provide their energy needs. In contrast, these deep-sea corals actively feed upon materials and nutrients in the water column. Deep-sea corals basically come in two types—hard or stony corals—which are similar to those found on tropical coral reefs and soft corals, which can be small and delicate or very large (up to 9 feet) and tree-like. Specifically, deep-sea corals are important for several reasons:

  • Deep-sea corals have a critical ecological role in that much like ancient forests they serve as habitat for a diversity of other organisms including fish and invertebrate communities, including commercially important fisheries species.
  • They may serve as important indicators of past climates. Like terrestrial trees, deep-sea corals add annual rings. While they are slow growing, some specimens have been estimated to be nearly 2,000 years old. Non-living corals have been carbon dated to be greater than 40,000 years old. In addition, corals have a much better time resolution than sediment cores and are unaffected by bioturbation.
  • Deep-sea coral ecosystems provide a rich biodiversity and as such are looked upon as a potential future source of novel bio-compounds for development by the pharmaceutical and biotechnology industries.

Future actions
NOAA should build on recent deep-sea coral meetings and workshops held over the past year. These have included the Deep-Sea Corals Collaboration Planning Meeting (11-2003 Tampa, FL), the Deep-Sea Corals Workshop (1-2003 Galway, Ireland), and the 2nd International Symposium on Deep-Sea Corals (9-2003 Erlangen, Germany).

Critical information needs and research themes have emerged from these sessions:

  • Locating and mapping these corals, with a priority on U.S. deep-sea coral habitats, which have been largely unmapped when compared to European and Canadian coral habitats.
  • A more comprehensive understanding of the biology and ecology of deep-sea corals by conducting a species inventory, growth and reproductive studies, and food web and species interaction studies.
  • Understanding the uses of specific deep-sea species of corals as indicators of climatic change.

Exploration and research of deep-sea corals are key to increasing our understanding and improving the effective management of these unique organisms. These studies should be multidisciplinary and utilize the unique technologies and capabilities available to the research community.


Deep sea paragorgia coral covered in zoanthids and a sea star

Deep sea paragorgia coral covered in zoanthids and a sea star, demonstrating the beauty and diversity of life on the New England Seamounts.


A single colony of slow-growing Lophelia pertusa coral

This single colony of slow-growing Lophelia pertusa coral was photographed during an OE-sponsored expedition to the Gulf of Mexico in 2003. Lophelia requires a hard substrate for attachment and growth, and this large boulder provided the necessary substrate.


Callogorgia coral with a solitary cup coral

This image of Callogorgia coral with a solitary cup coral is from video footage of the last ROV dive at Mississippi Canyon in the OE-sponsored cruise to the Gulf of Mexico in 2003.


This large pink sea fan is nearly two meters tall and is held in place by a holdfast nearly 12 cm in diameter.

This large pink sea fan belongs to the genus Paragorgia. This specimen is nearly two meters tall and is held in place by a "holdfast" nearly 12 cm in diameter. It holds within its branches a thriving community of brittle stars, crabs, and shrimp - giving it the appearance of a well-decorated Christmas tree. This image was taken during the OE-sponsored expedition to explore Gulf of Alaska seamounts in 2002.

NOAA Research programs that study Deep-sea Corals

NOAA's Undersea Research Program
NOAA’s Ocean Explorer Program



Additional Related Information:

NOAA conducts a variety of research on deep-sea corals through NOAA Fisheries, NOAA Research and the National Ocean Service. NOAA Fisheries conducts its research through its regional science centers in Alaska, the northeast and southwest. NOS utilizes the national Marine Sanctuary Program in conjunction with the Office of Ocean Exploration and NOAA's Undersea Research Program.

Deep-sea Corals Workshop Summary reportpdf
National Marine Sanctuary Program
Northeast Fisheries Science Center
Southeast Fisheries Science Center
Fisheries Science Center Alaska
NOAA's National Ocean Service




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