Atoll

Atoll is a coral island or an island of coral which forms a barrier to a lagoon. It either encircles a lagoon partially or completely. The term “Atoll” was generated from a language Divehi spoken in Maldives. Atoll hence means an island usually formed by corals or volcanic eruptions and which form a lagoon in the sea.

Maldives, the country is formed by 1200 islands arranged in 26 atolls. The scenic beauty is stupendous.

Charles Darwin had first explained how an Atoll is formed. In simple language, Oceanic Volcanoes erupt and form islands in the sea. It takes years for the mountainous structure created by the volcano to subside and recede. By the time it recedes biotic growth occurs around the volcanic mountain near the surface of the sea. These biotic remain near the surface and after the mountainous structure recedes below sea level, the biotic structures, corals, form a barrier or wall or reef. They form a ring in the shape of the receded volcanic mountain. The water inside the reef is called a lagoon and the remaining land together forms an island. Atolls are the product of growth of tropical marine organisms and hence they are only formed in warm waters of the tropics.

Saya De Malha Bank is the world’s largest Atoll with an area of 40,000 sq km. It is located in the western Indian Ocean and close to Madagascar. It is on the South East of Seychelles. The closest land to this Atoll is the Agalega Islands, a dependency of Mauritius. Mauritius administers Saya De Malha as its exclusive economic zone.

Atolls have shallow water bed and hence the flora and fauna are different from the main sea. Most of the lagoons have beautiful scenery and are tourist attractions. Maldives, as said earlier has only Atolls and no major land; hence it is receding and sinking every passing year.

Linus Orakles
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