An atoll (/ ˈæt.ɒl, - ɔːl, - oʊl, əˈtɒl, - ˈtɔːl, - ˈtoʊl /) [1] is a ring-shaped island, including a coral rim that encircles a lagoon. There may be coral islands or cays on the rim. [2][3] Atolls are located in warm tropical or subtropical parts of the oceans and seas where corals can develop.

atoll, coral reef enclosing a lagoon. Atolls consist of ribbons of reef that may not always be circular but whose broad configuration is a closed shape up to dozens of kilometres across, enclosing a lagoon that may be approximately 50 metres (160 feet) deep or more.

2019年4月17日 · The modern definition of atoll describes it as an annular reef that has enclosed a lagoon in which there is no raised mass of land projecting into the body of water. Atolls are mostly hidden by ocean waves, with some wrecking canoes and ships.

What is an “atoll”? For reef scientists, atolls are broadly defined as a large, ring-shaped coral reefs that surround a central lagoon. Coming up with a more specific and unambiguous definition of such reef formations is not all that easy however.

2023年10月19日 · An atoll is a ring-shaped coral reef, island, or series of islets. An atoll surrounds a body of water called a lagoon. Sometimes, atolls and lagoons protect a central island. Channels between islets connect a lagoon to the open ocean or sea. Atolls develop with underwater volcanoes, called seamounts. First, the volcano erupts, piling up lava on ...

2024年2月23日 · Atolls are ring-shaped coral reefs, islands, or a series of islets that encircle a lagoon either partially or completely. The shape of atolls varies with some being elliptical or circular in shape and others having an angular shape. Atolls also vary in size.

2024年10月12日 · Atolls are ring-shaped coral reefs surrounding a central lagoon, formed by the erosion and sinking of volcanic islands over millions of years. Approximately 440 atolls exist worldwide, with the majority located in the Pacific Ocean. Atolls are predominantly found in warm tropical or subtropical regions where coral growth is supported.

When the island completely subsides beneath the water, it leaves a ring of growing coral with an open lagoon in its center, this is called an atoll. The process of atoll formation may take as long as 30 million years to occur.

2017年4月25日 · An atoll is a ring-shaped coral reef or series of coral rims that encircle a lagoon either partially or wholly. Atoll and lagoons form a rim around an island that offers protection to the central island.

2021年11月15日 · An atoll is a ring-shaped coral reef, island or chain of islands around a body of water called a lagoon. An atoll forms when an underwater volcano spills lava onto the seafloor. Over many eruptions, that volcanic rock piles up.