Usually, coral reefs are linked to shallow waters of tropical seas, but these specific ones are situated in mid-depth (500–2000 m depth, and beyond) and grow in food-limited areas with temperatures of 4 °C to 12 °C.
A big difference between cold and tropical reefs is that cold reefs don’t have a symbiotic alga, so they aren’t limited in areas with sunlight since they do not obtain any energy directly from sunlight.
Being one of the most productive ecosystems in the deep-sea and a “hotspot” for biodiversity they are very important, at the same level of shallow-water coral reefs. These structures act like islands in the flat, featureless and muddy surroundings and harbour a distinct and rich ecosystem, providing niches and nursery grounds for a variety of deep-sea species.
Cold-water coral ecosystems are long lived, slow growing and fragile. They face both local and global threats, including physical destruction (i.e bottom fisheries, mineral exploration and production, cable and pipeline placement, repair and dumping), chemical pollution, aquaculture production as well as warming and acidifying waters as a consequence of climate change.