Atoll in the context of "Ralik"

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⭐ Core Definition: Atoll

An atoll (/ˈæt.ɒl, -ɔːl, -l, əˈtɒl, -ˈtɔːl, -ˈtl/) is a ring-shaped island, including a coral rim that encircles a lagoon. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop. Most of the approximately 440 atolls in the world are in the Pacific Ocean.

Two different, well-cited models, the subsidence model and the antecedent karst model, have been used to explain the development of atolls. According to Charles Darwin's subsidence model, the formation of an atoll is explained by the sinking of a volcanic island around which a coral fringing reef has formed. Over geologic time, the volcanic island becomes extinct and eroded as it subsides completely beneath the surface of the ocean. As the volcanic island subsides, the coral fringing reef becomes a barrier reef that is detached from the island. Eventually, the reef and the small coral islets on top of it are all that is left of the original island, and a lagoon has taken the place of the former volcano. The lagoon is not the former volcanic crater. For the atoll to persist, the coral reef must be maintained at the sea surface, with coral growth matching any relative change in sea level (sinking of the island or rising oceans).

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Atoll in the context of Island

An island or isle is a piece of land, distinct from a continent, completely surrounded by water. There are continental islands, which were formed by being split from a continent by plate tectonics, and oceanic islands, which have never been part of a continent. Oceanic islands can be formed from volcanic activity, grow into atolls from coral reefs, and form from sediment along shorelines, creating barrier islands. River islands can also form from sediment and debris in rivers. Artificial islands are those made by humans, including small rocky outcroppings built out of lagoons and large-scale land reclamation projects used for development.

Islands are host to diverse plant and animal life. Oceanic islands have the sea as a natural barrier to the introduction of new species, causing the species that do reach the island to evolve in isolation. Continental islands share animal and plant life with the continent they split from. Depending on how long ago the continental island formed, the life on that island may have diverged greatly from the mainland due to natural selection.

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Atoll in the context of Tuvalu

Tuvalu (/tˈvɑːl/ too-VAH-loo) is an island country in the Polynesian sub-region of Oceania in the Pacific Ocean, about midway between Hawaii and Australia. It lies east-northeast of the Santa Cruz Islands (which belong to the Solomon Islands), northeast of Vanuatu, southeast of Nauru, south of Kiribati, west of Tokelau, northwest of Samoa and Wallis and Futuna, and north of Fiji.

Tuvalu is composed of three reef islands and six atolls spread out between the latitude of and 10° south and between the longitude of 176° and 180°. They lie west of the International Date Line. The 2022 census determined that Tuvalu had a population of 10,643, making it the 194th most populous country, exceeding only Niue and the Vatican City in population. Tuvalu's total land area is 25.14 square kilometres (9.71 sq mi).

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Atoll in the context of Lagoon

A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as a reef, a barrier island or islands, a barrier peninsula, or an isthmus. Lagoons are commonly divided into coastal lagoons (or barrier lagoons) and atoll lagoons. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around many parts of the world.

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Atoll in the context of Hawaiian Islands

The Hawaiian Islands (Hawaiian: Mokupuni Hawaiʻi) are an archipelago of eight major volcanic islands, several atolls, and numerous smaller islets in the North Pacific Ocean, extending some 1,500 miles (2,400 kilometers) from the island of Hawaiʻi in the south to northernmost Kure Atoll. Formerly called the Sandwich Islands by Europeans, the present name for the archipelago is derived from the name of its largest island, Hawaiʻi.

The archipelago sits on the Pacific Plate. The islands are exposed peaks of a great undersea mountain range known as the Hawaiian–Emperor seamount chain, formed by volcanic activity over the Hawaiian hotspot. The islands are about 1,860 miles (3,000 km) from the nearest continent and are part of the Polynesia subregion of Oceania.

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Atoll in the context of British Indian Ocean Territory

The British Indian Ocean Territory (BIOT) is a British Overseas Territory situated in the Indian Ocean. The territory comprises the seven atolls of the Chagos Archipelago with over 1,000 individual islands, many very small, amounting to a total land area of 60 square kilometres (23 square miles). The largest and most southerly island is Diego Garcia, 27 square kilometres (10 square miles), the site of a Joint Military Facility of the United Kingdom and the United States. Official administration is remote from London, though the local capital is often regarded as being on Diego Garcia.

Mauritius claimed that the British government separated the Chagos Archipelago from Mauritius, creating a new colony, the British Indian Ocean Territory (BIOT). However, this was disputed by the United Kingdom, who said that the Chagos Islands had no historical or cultural ties to Mauritius, and that they were only governed during the colonial period from Mauritius (2191 km or 1361 miles away) as an administrative convenience. Mauritius further claimed that to avoid accountability to the United Nations for its continued colonial rule, the UK falsely claimed that the Chagos had no permanent population.

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Atoll in the context of Atolls of Maldives

The Maldives consists of 20 natural atolls, along with a few islands and isolated reefs stretching from 7 degrees 10 minutes north to 0 degrees 45 minutes south. The largest of these atolls is Boduthiladhunmathi, while the atoll containing the most islands is Huvadhu.

Some atolls are in the form of a number of islands by time and in the form of isolated reefs, which could be classified as smaller atoll formations. All land above the surface in the Maldives is of coralline origin. The atolls of the Maldives form a quite regular chain and, especially in the northern and central atolls, an arrayed structure is apparent. There are broad and deep channels between some atolls. The origin of the word "atoll" itself is in the language of the Maldives. "Atoll" (from Dhivehi: atholhu) is now used in many languages worldwide.

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Atoll in the context of French Polynesia

French Polynesia (/ˌpɒlɪˈnʒə/ POL-ih-NEE-zhə; French: Polynésie française [pɔlinezi fʁɑ̃sɛːz] ; Tahitian: Pōrīnetia farāni) is an overseas collectivity of France and its sole overseas country. It comprises 121 geographically dispersed islands and atolls stretching over more than 2,000 kilometres (1,200 mi) in the South Pacific Ocean. French Polynesia is associated with the European Union as an overseas country and territory (OCT). The total land area of French Polynesia is 3,521 square kilometres (1,359 sq mi), with a population of 282,596 as of September 2025 of which at least 205,000 live in the Society Islands and the remaining population lives in the rest of the archipelago.

French Polynesia is divided into five island groups: the Austral Islands; the Gambier Islands; the Marquesas Islands; the Society Islands (comprising the Leeward and Windward Islands); and the Tuamotus. Among its 121 islands and atolls, 75 were inhabited at the 2017 census. Tahiti, which is in the Society Islands group, is the most populous island, being home to nearly 69% of the population of French Polynesia as of 2017. Papeete, located on Tahiti, is the capital of French Polynesia. Although not an integral part of its territory, Clipperton Island was administered from French Polynesia until 2007.

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Atoll in the context of Tokelau

Tokelau (/ˈtkəl/ ; lit.'north-northeast' or 'north wind'; known previously as the Union Islands, and, until 1976, known officially as the Tokelau Islands) is a dependent territory of New Zealand in the southern Pacific Ocean. It consists of three tropical coral atolls: Atafu, Nukunonu, and Fakaofo. They have a combined land area of 10 km (4 sq mi). In addition to these three, Swains Island (Olohega), which forms part of the same archipelago, is the subject of an ongoing territorial dispute, while being currently administered by the United States as part of American Samoa. Tokelau lies north of the Samoan Islands, east of Tuvalu, south of the Phoenix Islands, southwest of the more distant Line Islands, and northwest of the Cook Islands.

Tokelau has a population of approximately 2,500 people; it has the fourth-smallest population of any sovereign state or dependency in the world. As of the 2016 census, around 45% of its residents had been born overseas, mostly in Samoa or New Zealand. The populace has a life expectancy of 69, which is comparable to that of other Oceanian island nations. Approximately 94% of the population speak Tokelauan as their first language. Tokelau has the smallest economy of any nation. It is a leader in renewable energy, being the first 100% solar-powered nation in the world.

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