Shallow-water coral reefs are sometimes called "the rainforests of the sea" for their extraordinary biological diversity, perhaps the highest anywhere on Earth. However, until quite recently, few people — even marine scientists — knew that the majority of coral species actually live in colder, darker depths, and that some of these form coral reefs. Based on current knowledge, deep-sea coral and sponge communities appear to be as important to the biodiversity of the oceans and the sustainability of fisheries as their analogues in shallow tropical seas.
Deep-sea corals structure spectacularly diverse seafloor communities and provide shelter, feeding habitats and breeding /nursery grounds to many fish and invertebrate species. As some deep-sea corals can live to be 1,800 years old, deep-sea corals can serve as archives of climate conditions that are important to understanding the Earth's past. Additionally, these rare corals are being used to develop new pharmaceutical protects to figh cancer, Alzhiemer’s disease, asthma, pain and viral infections. Despite the ecological importance of deep-sea coral and sponge ecosystems, relatively little is known about the biology and distribution of these ecosystems. However, they continue to be greatly impacted by destructive fishing practices such as bottom trawling.
