The existence of cold-water corals has been known since the 18th Century, but the vast number of reefs found in the deeper reaches of the world's waters has amazed researchers. Yet just as scientists are beginning to understand the significance of the coral to the surrounding environment, they are also witnessing destruction.It is only in the past few decades that technology allowing humans to peer into the previously uncharted depths has become available to scientists. One of the most startling discoveries has been the number of coral reefs living hundreds of metres beneath the surface, in temperatures ranging from 4-13C (39-55F).

'Glacial' growth

Environmentalists point the finger of blame at the fishing industry and the practice of bottom-trawling with drag nets.This method of fishing involves scouring the sea bed with huge nets that are some 60m-wide; they are held apart by two huge metal plates weighing up to five tonnes.

It's heavy gear, and the reefs and the coral colonies are very fragile and easily damaged," Jan Helge Fossa, chief scientist at the Norwegian Institute of Marine Research, tells TVE's Earth Report programme for BBC World.

Cold corals are very slow growing. Some individuals are estimated to be up to 1,800 years old, and many reefs began forming at the end of the last Ice Age.
Damage inflicted by bottom-trawling can result in catastrophic consequences for the species living amid the reefs.