Atoll Atoll An atoll (, , , , or ), sometimes called a coral atoll, is a ring-shaped coral reef including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. The coral of the atoll often sits atop the rim of an extinct seamount or volcano which has eroded or subsided partially beneath the water. The lagoon forms over the volcanic crater or caldera while the higher rim remains above water(s) or at shallow depths that permit the coral to grow and form the reefs. For the atoll to persist,
Atoll fruit dove species is rather tame and is rare in inhabited areas making hunting a possible threat. Atoll fruit dove The atoll fruit dove ("Ptilinopus coralensis") is a species of bird in the family Columbidae. It is endemic to the Tuamotu archipelago in French Polynesia. Its natural habitats are subtropical or tropical moist lowland forests and plantations. It is threatened by habitat loss. The atoll fruit dove is widespread throughout the islands of the Tuamotu Archipelago, French Polynesia. In a 1999 survey it was found to be uncommon on five out of eight islands visited, but others have found it to be