The depth record for deep-sea fans is held by Convexella krampi at 5850 meters in the frigid Antarctic, North Atlantic, and Kermadec Trench.
The deep-sea gorgonian genus Iridogorgia sp. is characterized by a partially calcareous axis with an open, upright spiral or helix arrangement (Verrill, 1883). Three new species were described last year (Watling 2007).
Many deep-water animals have never been photographed alive in their natural habitat, they’re known only from their pickled state. Dried, dusty, and broken specimens fill museum drawers.
The biodiversity of Lophelia pertusa bioherms in the North Atlantic rivals the diversity of a shallow water tropical reef. More than 800 associated species have been documented in association.