An Island is a piece of land surrounded on all sides by water. It may occur individually or in a group in open oceans or seas.
Types of Islands
* These Islands were initially part of the mainland and are now detached from the continent.
* Continental Islands may appear as individual Island or Island groups, Festoons.
e.g.: Madagascar, ceylon, the British Isels, East Indies... etc.,
* These Islands are normally small and are located in the midst of oceans and have no connection with the mainland.
* Flora and Fauna is very less and are very sparsely populated.
* Some of the Islands provide useful stops for aeroplanes.
e.g.: Mariana Islands, Republic of Mauritius.
* The Island which are formed as a result of the cones of volcanoes that rise from the ocean bed.
* Among these, some are extinct while some are active ones.
e.g.: Mauna Loa in Hawaii of 13,680 feet above sea level.
* These Islands are very much lower and emerge just above the water surface.
* These are builtup by coral animals which are found both near the shores of the mainland and in the midst of oceans.
e.g.: Marshall Islands, Gilbert and Ellice Island, the Pacific and Maldives of Indian ocean.
* Coral reefs are the Islands that are formed as a result of residing of Polyps, marine organisms which have the ability to secrete Calcium Carbonate. In order to have these reefs by the coral polyps, following conditions must be fulfil. They are
* The water temperature must not fall below 20oC
* The depth of water should not exceed 180 feet because beyond this depth sunlight is too feeble for photosynthesis to take place.
* The water should be saltish and free from sediment. These are of 3 kinds. They are
1) Fringing Reefs
2) Barrier Reefs