↑ 10 Most Captivating Atolls in the World.

Rising Seas Already Threatening Coral Atolls.

Density-induced water circulations in atoll coral reefs: A numerical study.

↑ Leclerc, A.-M., Jean-Baptiste, P., Texier, D., & Broc, D.You can help the SEG Wiki by expanding it. Atoll: Formation and Distribution, by Encyclopedia of Earth.Other closely related articles in this wiki include: The top 10 Atolls in the world are (from 10-1), Funafuti, Bikini Atoll, Tubbatha Reef, Lighthouse Reef, Tikehau, Caroline Island, Aitutaki Atoll, Aldabra, Rangiroa, and Atolls of the Maldives. These atolls are found in the tropics and the subtropics. Along with the rising sea levels, the changes in storm intensity, rainfall, and ocean water temps also have an impact. This rise in sea level is a result of the global temperature increasing. The rising sea levels is a current problem for coral atolls. Scientists need satellite images to study the ecological health of the reefs. There are around 150 different species, meaning the corals are species are rich and well diverse. The effects of global warming could be causing the species of the GBR to possibly shift southwards. When the growth of the atoll is stimulated the platform thickness increases the velocity of the water flow. The inward and upward circulation of water into these atoll's was studied and the negative temperature gradients were measured and the salinity increased the flow rate by 35%. Groundwater flow into Atoll's is impacted by the structure and the temperature. A large percentage of the world's atolls are in the central and southwestern pacific and in parts of the Indian oceans, and a number are found, mainly on the continental shelves, in the Caribbean. Atoll formation requires strong light and warm waters. Reefs are typically grouped into 3 categories: atoll, barrier, and fringe reef. The hydrological and geological conditions that occur in these different areas cause these reefs to occur in different areas of the tropics. An atoll's formation depends on the conditions of water temperature, erosion, salinity, sedimentation, and its sinking rate. įormation of Atoll Distribution and developmentĪtoll's form from an volcanic island or a guyot. Ocean waves also break pieces of the limestone reef, causing the atoll to form as well. The island becomes this guyot, or a ring-shaped fringing reef and turns into a barrier reef. With this subsidence, the flat-topped seamount is called a guyot. Over millions of years, the volcanic island erodes and sinks to the seafloor. This forms just below the surface of the ocean. A fringing reef is formed and surrounds the island. Sea animals called corals also play a part in the role of this development. FormationĪtoll's develop with underwater volcanoes, called seamounts. As the island sinks, the surrounding territory of the island falls. Atoll was the result of the gradual sinking of a volcanic island that has ling since cooled, leaving behind an open crater in the middle section of the island. These theories came from personal observations he made during his 6 year voyage around the southern section of the Pacific Ocean. Īnother theory of their formation Darwin came up with was that the formation process having its roots in volcanic activity. Darwin's theory was believed for a very long time, but a study published May 9 in the journal Geology proved different than what Darwin thought. Ĭharles Darwin's view on the natural progression of life, and the evolution of coral atolls, and if his statements were correct, Darwin developed the theory that coral atolls grow as reefs and stretch toward sunlight while the ocean islands slowly sink beneath the sea surface. In 1968, a number of radiological surveys were conducted on the island. 23 weapons testing over this period of time. By July 1958 however, the nuclear testing in the Marshall Islands was terminated. During this time, the 167 inhabitants were moved to neighboring islands. In 1946, Bikini Atoll was the first site in the Marshall Islands used for nuclear weapon testing by the US. Atoll is located northwest of Majuro on the northern fringe of the Marshall Islands and is composed of more than 23 islands and islets.

Atoll coral reef