Coral Forests of the Deep


NOAA studies and conserves deep-sea corals

Learn more about deep-sea corals


NOAA Marine Fisheries Service

US Coral Reef Conservation Program

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NARRATOR: Most corals were once thought to live in tropical water, close enough to the surface to receive sunlight. But with the help of submersibles and remotely operated vehicles, scientists have discovered vast forests of corals living 200 to 10,000 feet deep in dark, cold waters.

Deep-sea corals can live for hundreds to thousands of years, feeding directly on microscopic animals. They've been found throughout the ocean on the rocky sea floor, in canyons, and on continental slopes. Like their shallow-water relatives, deep-sea corals provide habitats for a huge variety of organisms. In fact, scientists discover new species on each mission to the deep.

These deep-water ecosystems are also important for commercial fish stocks, such as crabs and halibut off the coast of Alaska, and monkfish off the coast of New England. Yet for all their value, researchers believe these ecosystems are at risk.

In certain areas the fishing industry uses bottom trawls to catch fish in deep-water habitats. As the nets are pulled along the ocean floor, they capture everything in their path, including corals they may accidentally encounter. Excess carbon dioxide from human activity on land is continually absorbed into the ocean increasing its acidity. This process, known as "ocean acidification," weakens coral skeletons and slows their growth.

Most deep-water coral are still unexplored and even undiscovered. We will need to identify, map, and study these beautiful yet fragile corals if we hope to protect them and the many species they support.