Osprey Reef Osprey Reef Osprey Reef is a submerged atoll in the Coral Sea, northeast of Queensland, Australia. It is part of the Northwestern Group of the Coral Sea Islands. Osprey Reef is roughly oval in shape, measuring , and covers around . It has a perimeter of . The central lagoon is only deep. The reef sits atop a seamount in deep water. It is an isolated location some from other reefs. The almost vertical reef walls, which rise from a depth of about , are home to a dwarf form of "Nautilus pompilius" that is isolated from other nautilus populations
Coral reef in open water rather than next to a shoreline. Like an atoll, it is thought that these reefs are formed either as the seabed lowered or sea level rose. Formation takes considerably longer than for a fringing reef, thus barrier reefs are much rarer. The best known and largest example of a barrier reef is the Australian Great Barrier Reef. Other major examples are the Belize Barrier Reef and the New Caledonian Barrier Reef. Barrier reefs are also found on the coasts of Providencia, Mayotte, the Gambier Islands, on the southeast coast coast of Kalimantan, on parts of the coast