The atoll of Tetiʻaroa in French Polynesia. An atoll (/ ˈ æ t. ɒ l,-ɔː l,-oʊ l, ə ˈ t ɒ l,-ˈ t ɔː l,-ˈ t oʊ l /) [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.Most of the approximately 440 ...

2025年1月21日 · An atoll is a ring of coral that originally grew completely around the shoreline of an island, and which continued to grow upward on top of itself as the island subsided or eroded away. As reef building corals thrive only in warm waters, atolls are only found in …

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 ...

This animation shows the dynamic process of how a coral atoll forms. Corals (represented in tan and purple) begin to settle and grow around an oceanic island forming a fringing reef. It can take as long as 10,000 years for a fringing reef to form.

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.

2018年1月29日 · Most of the world’s great atolls are located in the Pacific Ocean, especially in the islands of Tuamotu, Caroline, Marshall, and the Coral Sea. The Great Chagos Bank is the largest atoll in the world, taking up a massive area of 12,642 square kilometers (4,881 square miles).

2024年7月21日 · Atolls are **coral**, not dirt. Corals need to grow fast enough to replace parts that wear away. They love warm water, so you'll spot atolls in tropical and subtropical places. These **vibrant reefs** and crystal-clear lagoons are full of marine life. Pretty neat, right? Think of an amazing tropical adventure.

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 .

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.

2023年10月19日 · The ring-shaped islands you see in the ocean are called coral atolls. They are created when coral reefs start to grow on a sinking island. Have you ever seen an image like the one below? Most people tend to think they’re just regular islands, but that’s not entirely true. These islands are called coral atolls.