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
Réunion's coral reef Réunion's coral reef Réunion is an island located near the eastern coast of Madagascar in the Indian Ocean. Its coral reef covers a concentrated part of the western littoral. The coral reef is located between St Leu and St Gilles. It is more than long and ranges in width from in its northern part at St. Gilles to in the south. Since the island is close to the continental shelf, the sea becomes deep not far from the coast. The presence of nearby deeper ocean currents supports a rich biodiversity fauna and flora in the reef environment. Coral reefs are