Coral reef to form fringing reefs, and can eventually grow become a barrier reef. Where the bottom is rising, fringing reefs can grow around the coast, but coral raised above sea level dies. If the land subsides slowly, the fringing reefs keep pace by growing upwards on a base of older, dead coral, forming a barrier reef enclosing a lagoon between the reef and the land. A barrier reef can encircle an island, and once the island sinks below sea level a roughly circular atoll of growing coral continues to keep up with the sea level, forming a central lagoon. Barrier reefs
Zhongzhou Reef Zhongzhou Reef Zhongzhou Reef also known as Ban Than Reef and Centre Cay (; ) is a small coral reef on the north edge of the Tizard Bank in the Spratly Islands, South China Sea. It lies east of ROC-occupied Taiping Island (Itu Aba), west of Vietnamese-occupied Sand Cay, and has an exposed area of approximately during high tide, and during low tide. It consists of an accumulation of seashells, sand, coral reefs and debris which forms a circular coral reef plate, surrounding the reef under the water, with a diameter of approximately . The reef is currently controlled by