Coral reef A fringing reef forms around an extinct volcanic island as the island and ocean floor subsides. As the subsidence continues, the fringing reef becomes a barrier reef and ultimately an atoll reef. Darwin predicted that underneath each lagoon would be a bedrock base, the remains of the original volcano. Subsequent research supported this hypothesis. Darwin's theory followed from his understanding that coral polyps thrive in the tropics where the water is agitated, but can only live within a limited depth range, starting just below low tide. Where the level of the underlying earth allows, the corals grow around the coast
Coral Sea Reserves Ramsar Site Geographic Society of Queensland which visited the Herald Cays and their surrounding reef in 1997. The site was designated as a wetland of international importance under the Ramsar Convention on Wetlands. It was listed on 21 October 2002 as Ramsar Site 1222. The site is centred on the Coral Sea Plateau, about 440 km east of Cairns, Queensland, and east of the Great Barrier Reef, from which it is separated by an area of deep water known as the Queensland Trough. Lihou Reef NNR lies to the south-east of the Coringa-Herald NNR and is separated from it by about 100