Islands around the world

As we know islands are nothing but an area of land surrounded by water and it must be smaller than a continent. This is the reason why Australia is not considered as an island. There are different types of islands. Greenland, which is the largest island in the world, is a continental island. Continental islands were once connected to the nearby continent. Some continental islands were formed while shifting continents broke apart millions of years ago. Some others were formed due to melting of glaciers causing sea level to go high and thereby flooding the surrounding low level areas. The tidal islands are also continental islands with the difference that during high tide, they become islands and during low tide they are connected to the mainland. Unlike continental islands,oceanic islands are not associated with any so called mainland. They are situated in the middle of oceans surrounded by deep seas. Oceanic islands are formed due to eruptions of undersea volcanoes. There are 10,000 submarine volcanoes throughout the world and more than 70 percent of those volcanoes erupt under the sea. Due to repeated eruptions, layers of solidified lava grows gradually. When it comes above the sea level, it forms an oceanic island. Of course this process takes millions of years. The world’s most populated island, Java of Indonesia, is an oceanic island. Archipelagos are the group of islands located in a particular geographical area. Bahamas archipelago comprises of 700 islands which are classified as coral islands. Coral islands are formed by the secretions of billions of tiny sea creatures called corals. Coral secrete a hard exoskeleton made of calcium carbonate (limestone). Underwater reefs are formed as these secretions combine with sand and rock. Reefs form islands as they become so large that they break above the water’s surface. An atoll is a type of coral island that surround a central lagoon. Before becoming atolls, they are ring-shaped coral reefs that encircle oceanic islands. Over millions of years, erosion may cause oceanic islands to sink into the earth’s crust. When this happens, only the atolls remain. Atolls are found primarily in the Pacific and Indian oceans. Barrier islands are most commonly found on the eastern coast of North America where they are popular vacation spots. These long narrow islands lie parallel to the coastline and separated from the mainland by narrow bays or lagoons. The islands are created by large offshore deposits of sand and sediment. Artificial (man-made) islands are also being built in different parts of the world. Egyptians were among the first to build artificial islands. Plans to build artificial islands are underway in many countries, including Denmark. In the meantime, new islands continue to appear naturally throughout the world. Volcanic eruptions have created new oceanic islands in the Pacific Ocean and Red Sea. With so many active underwater volcanoes, no one knows when the world’s next island will appear. The only thing that is certain is that new islands will continue to populate the world’s waters. Do you Know : • Many atolls are so remote that they have been used as testing sites for nuclear weapons. • The world’s most populated island of Java is the world’s thirteenth largest island and has a population of approximately 140 million. • Greenland, the largest island in the world, has a population of less than 57,000. • Kansai International Airport in Japan is built on two artificial islands in Osaka Bay. The islands are sinking and may sink to sea level by 2056. • More than 10 percent of the world’s population lives on islands. ********