What is an atoll in geography?

An atoll is a ring-shaped coral reef, island, or series of islets. The atoll surrounds a body of water called a lagoon. 4 - 12+ Earth Science, Geography, Geology, Oceanography, Physical Geography, Social Studies, World History.

What is an atoll and how does it form?

An atoll develops from a coral reef that rings a volcanic island.

What is atoll with example?

atoll • \AT-tawl\ • noun. : a coral island consisting of a reef surrounding a lagoon. Examples: The Marshall Islands, in the central Pacific Ocean, consist of five islands and 29 atolls, which are each made up of many islets.

What is the meaning of an atoll?

An atoll is a ring-shaped coral reef, island or chain of islands around a body of water called a lagoon.

What is an example of an atoll in geography?

Pieces of coral get eroded into tiny grains of sand that pile up on the reef to form tiny islets or a ring-shaped island. Examples of atolls include the islands of the Maldives, Polynesia, and Micronesia.

How an Atoll is formed

What's the difference between an island and an atoll?

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.

Is the Great barrier reef an atoll?

There are no atolls in the system, and reefs attached to the mainland are rare. Fringing reefs are distributed widely, but are most common towards the southern part of the Great Barrier Reef, attached to high islands, for example, the Whitsunday Islands.

Is Tahiti an atoll?

Commonly referred to as The Islands of Tahiti, French Polynesia is a collection of 118 islands and atolls scattered across an impressive nautical surface area the size of Western Europe. Still, these tiny islands—many of which remain uninhabited—make up a total landmass of only 1,600 square miles (4,100 sq. km).

Where are the atolls?

Most of the world's atolls are in the Pacific Ocean (with concentrations in the Caroline Islands, the Coral Sea Islands, the Marshall Islands, the Tuamotu Islands, Kiribati, Tokelau, and Tuvalu) and the Indian Ocean (the Chagos Archipelago, Lakshadweep, the atolls of the Maldives, and the Outer Islands of Seychelles).

How many atolls are in the world?

There are 439 atolls identified in the present summary, but the list is broadly constructed, inclusive, and not limited to those known to have formed on subsiding volcanic platforms. In addition, 171 of those listed (39%) are primarily subtidal atoll reefs with little or no island development.

Is Fiji an atoll?

Atolls of the western and central Pacific, including Fiji, New Caledonia, Australia's Pacific coast, the Marshall Islands, the Gilbert Islands, Tuvalu, Hawaii, and the Cook Islands. Compare to atoll lists in Tables A.

Is Bermuda an atoll?

Islands formed in this manner are called atolls, and while atolls are not uncommon in the Pacific, Bermuda is the only atoll in the Atlantic Ocean.

How deep is the water in atolls?

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.

What is the difference between a barrier reef and an atoll?

Atolls are usually circular or oval in shape, with an open lagoon in the center. Barrier reefs are similar to fringing reefs in that they also border a shoreline; however, instead of growing directly out from the shore, they are separated from land by an expanse of water.

Are there any atolls in the Caribbean?

You usually hear the word atoll — meaning a ring-shaped coral island, reef, or chain of islands — associated with the South Pacific, but the Caribbean has its very own atoll off the coast of Belize.

Does France own any islands?

The Islands of Guadeloupe, Martinique, Saint-Martin, Saint-Barthélemy, Saint Pierre and Miquelon (Atlantic Ocean)

What country is Bora Bora in?

The Bora Bora island is one of the most popular islands in The Islands of Tahiti. One of nine islands within the Society Islands, Bora Bora was formed over seven million years ago by a volcano. Like most of the islands of French Polynesia, Bora Bora is surrounded by a ring of coral reef, also known as an atoll.

Why is it called French Polynesia?

The Pomare Dynasty ruled Tahiti until 1880 when King Pomare V was persuaded to cede Tahiti and most of its dependencies to France. By 1958, all The Islands of Tahiti were reconstituted as an French Overseas Territory and renamed French Polynesia.

Are atolls habitable?

Most atoll islands have limited adaptation space, land available for human habitation (7–9), and water and food sources (10, 11), and most have ecosystems that are vulnerable to seawater inundation (12).

Do atolls float?

The first and most important fact, discovered by none other than Charles Darwin, is that coral atolls essentially "float" on the surface of the sea. Atolls exist in a delicate balance between new sand and coral rubble being added from the reef, and sand and rubble being eroded by wind and wave back into the sea.

Where is the world's longest reef?

Stretching for 1,429 miles over an area of approximately 133,000 square miles , the Great Barrier Reef is the largest coral reef system in the world. The reef is located off the coast of Queensland, Australia, in the Coral Sea.

How many islands does an atoll have?

It is a small natural atoll 22 kilometres (14 miles) in length. It has 25 islands lying all around the boundary reef. One long barrier reef forms the western side of the atoll. There are several coral patches in the lagoon and the general depth in the centre is 20 to 30 fathoms (35 to 55 m).

How long does it take for an atoll to form?

When the island completely subsides beneath the water leaving a ring of growing coral with an open lagoon in its center, it is called an atoll. The process of atoll formation may take as long as 30,000,000 years to occur.

Why do atolls always form rings?

When seas fall, exposing a pre-existing pile of carbonate rocks, rainwater dissolves the center of those rocks and leaves behind a depression. When seas rise, corals build themselves up in a ring around that depression, forming an atoll. No volcano is needed.