People are well aware of the existence and relevance of coral reefs that occur in tropical seas. They are well known for their structural beauty but also because the reefs they form are generally the home of abundant, diverse and colorful communities of fishes and invertebrates.
But corals are not restricted to the shallow waters of tropical seas. Well deep in the ocean, well beyond the blue light many species of corals compete in diversity and complexity with their shallower relatives.