Atoll remains of an ancient atoll as a hill in a limestone area is called a reef knoll. The second largest atoll by dry land area is Aldabra with 155 km². The largest atoll in terms of island numbers is Huvadhu Atoll in the south of the Maldives with 255 islands. In 1842, Charles Darwin explained the creation of coral atolls in the southern Pacific Ocean based upon observations made during a five-year voyage aboard from 1831 to 1836. Accepted as basically correct, his explanation involved considering that several tropical island types—from high volcanic island, through barrier reef island, to atoll—represented
Atoll fruit dove 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 abundant on some atolls which have remained free from the ravages of introduced predators. The