Coral reef islands and atolls. The reef face is the zone above the reef floor or the reef drop-off. This zone is often the reef's most diverse area. Coral and calcareous algae provide complex habitats and areas that offer protection, such as cracks and crevices. Invertebrates and epiphytic algae provide much of the food for other organisms. A common feature on this forereef zone is spur and groove formations that serve to transport sediment downslope. The reef flat is the sandy-bottomed flat, which can be behind the main reef, containing chunks of coral. This zone may border a lagoon and serve as
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