|
Coral Reefs Of Tuvalu
The coral reefs of Tuvalu consist of three reef islands and six atolls, containing approximately of reef platforms. The islands of the Tuvalu archipelago are spread out between the latitude of 5° to 10° south and longitude of 176° to 180°, west of the International Date Line. The islands of Tuvalu are volcanic in origin. On the atolls, an annular reef rim surrounds the lagoon, and may include natural reef channels. The reef islands have a different structure to the atolls, and are described as reef platforms as they are smaller tabular reef platforms that do not have a salt-water lagoon, although they may have a completely closed rim of dry land, with the remnants of a lagoon that has no direct connection to the open sea or that may be drying up. Structure of the reefs of Tuvalu The islands of the Tuvalu archipelago are very low-lying, with the highest elevation of above mean sea level on Niulakita. The atolls and reef islands of Tuvalu have been formed from ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blue Coral
Blue coral (''Heliopora coerulea'') is a species of colonial coral. It is the only octocoral known to produce a massive skeleton. This skeleton is formed of aragonite, similar to that of scleractinia. Individual polyps live in tubes within the skeleton and are connected by a thin layer of tissue over the outside of the skeleton. Description The blue coral is the only extant octocoral with a massive skeleton, which is composed of fibrocrystalline aragonite (calcium carbonate). It is a hermatypic zooxanthellaete species with either blue or grey-grey polyps located within its skeleton, which each contain eight tentacles. Its colonies are either columnar, plates or branched. It is a tolerant species and is used in marine aquariums. Iron salts give the skeleton of ''Heliopora coerulea'' its unique color, which allows for easy recognition in fossil outcrops. As such, it is fairly abundant within paleontology, with fossils indicating the species has remained unchanged since the Cretac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latitude
In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pole, with 0° at the Equator. Lines of constant latitude, or ''parallels'', run east–west as circles parallel to the equator. Latitude and ''longitude'' are used together as a coordinate pair to specify a location on the surface of the Earth. On its own, the term "latitude" normally refers to the ''geodetic latitude'' as defined below. Briefly, the geodetic latitude of a point is the angle formed between the vector perpendicular (or ''normal'') to the ellipsoidal surface from the point, and the plane of the equator. Background Two levels of abstraction are employed in the definitions of latitude and longitude. In the first step the physical surface is modeled by the geoid, a surface which approximates the mean sea level over the ocean ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Structure And Distribution Of Coral Reefs
''The Structure and Distribution of Coral Reefs, Being the first part of the geology of the voyage of the Beagle, under the command of Capt. Fitzroy, R.N. during the years 1832 to 1836'', was published in 1842 as Charles Darwin's first monograph, and set out his theory of the formation of coral reefs and atolls. He conceived of the idea during the voyage of the ''Beagle'' while still in South America, before he had seen a coral island, and wrote it out as HMS ''Beagle'' crossed the Pacific Ocean, completing his draft by November 1835. At the time there was great scientific interest in the way that coral reefs formed, and Captain Robert FitzRoy's orders from the Admiralty included the investigation of an atoll as an important scientific aim of the voyage. FitzRoy chose to survey the Keeling Islands in the Indian Ocean. The results supported Darwin's theory that the various types of coral reefs and atolls could be explained by uplift and subsidence of vast areas of the Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation Of Coral Reefs
A coral reef is an underwater ecosystem characterized by reef-building corals. Reefs are formed of colonies of coral polyps held together by calcium carbonate. Most coral reefs are built from stony corals, whose polyps cluster in groups. Coral belongs to the class Anthozoa in the animal phylum Cnidaria, which includes sea anemones and jellyfish. Unlike sea anemones, corals secrete hard carbonate exoskeletons that support and protect the coral. Most reefs grow best in warm, shallow, clear, sunny and agitated water. Coral reefs first appeared 485 million years ago, at the dawn of the Early Ordovician, displacing the microbial and sponge reefs of the Cambrian. Sometimes called ''rainforests of the sea'', shallow coral reefs form some of Earth's most diverse ecosystems. They occupy less than 0.1% of the world's ocean area, about half the area of France, yet they provide a home for at least 25% of all marine species, including fish, mollusks, worms, crustaceans, echinoderms, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society Of London
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal charter by King Charles II as The Royal Society and is the oldest continuously existing scientific academy in the world. The society is governed by its Council, which is chaired by the Society's President, according to a set of statutes and standing orders. The members of Council and the President are elected from and by its Fellows, the basic members of the society, who are themselves elected by existing Fellows. , there are about 1,700 fellows, allowed to use the postnominal title FRS (Fellow of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fongafale
Fongafale (also spelled Fogale or Fagafale) is the largest of Funafuti's islets in Tuvalu. It is a long narrow sliver of land, 12 kilometres long and between 10 and 400 metres wide, with the South Pacific Ocean and reef on the east and the protected lagoon on the west. The north part is the Tengako peninsula, and Funafuti International Airport runs from northeast to southwest on the widest part of the island, with the village and administrative centre of Vaiaku on the lagoon side. On Fongafale, the Funafuti Kaupule is responsible for approval of the construction of houses or extensions to existing buildings on private land, and the Lands Management Committee is the responsible authority in relation to lands leased by government. In 1972, Funafuti was in the path of Cyclone Bebe. Cyclone Bebe knocked down 90% of the houses and trees on Fongafale. The storm surge created a wall of coral rubble along the ocean side of Fongafale and Funafala that was about long, and about to thic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Submarine Volcano
Submarine volcanoes are underwater vents or fissures in the Earth's surface from which magma can erupt. Many submarine volcanoes are located near areas of tectonic plate formation, known as mid-ocean ridges. The volcanoes at mid-ocean ridges alone are estimated to account for 75% of the magma output on Earth.Martin R. Speight, Peter A. Henderson, "Marine Ecology: Concepts and Applications", John Wiley & Sons, 2013. . Although most submarine volcanoes are located in the depths of seas and oceans, some also exist in shallow water, and these can discharge material into the atmosphere during an eruption. The total number of submarine volcanoes is estimated to be over 1 million (most are now extinct) of which some 75,000 rise more than 1 km above the seabed. Only 119 submarine volcanoes in Earth's oceans and seas are known to have erupted during the last 11,700 years. Hydrothermal vents, sites of abundant biological activity, are commonly found near submarine volcanoes. Effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lagoon
A lagoon is a shallow body of water separated from a larger body of water by a narrow landform, such as reefs, barrier islands, barrier peninsulas, or isthmuses. Lagoons are commonly divided into ''coastal lagoons'' (or ''barrier lagoons'') and ''atoll lagoons''. They have also been identified as occurring on mixed-sand and gravel coastlines. There is an overlap between bodies of water classified as coastal lagoons and bodies of water classified as estuaries. Lagoons are common coastal features around many parts of the world. Definition and terminology Lagoons are shallow, often elongated bodies of water separated from a larger body of water by a shallow or exposed shoal, coral reef, or similar feature. Some authorities include fresh water bodies in the definition of "lagoon", while others explicitly restrict "lagoon" to bodies of water with some degree of salinity. The distinction between "lagoon" and "estuary" also varies between authorities. Richard A. Davis Jr. restrict ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Islands Of Tuvalu
Tuvalu consists of nine separate islands: six atolls and three reef islands. An atoll typically consists of several islets: Tuvalu has a total of 124 islands and islets. Each island is surrounded by a coral reef. Tuvalu's small, widely scattered atolls have poor soil and a total land area of only about making Tuvalu the fourth-smallest country in the world. The sea level at the Funafuti tide gauge has been rising at a rate of 3.9 mm per year, and it has been determined that rising sea levels are causing more wave energy to be transferred across reef surfaces, which has tended to push more sand onto island shorelines, increasing islands’ land area. Over a recent four-decade period, there was a net increase in the land area of the islets of 2.9% (73.5 ha), although the changes were not uniform: About 74% of them increased in size and about 27% decreased in size. Islands of Tuvalu The islands of Tuvalu are spread out between the latitude of 5° to 10° south and longitude ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Date Line
The International Date Line (IDL) is an internationally accepted demarcation on the surface of Earth, running between the South and North Poles and serving as the boundary between one calendar day and the next. It passes through the Pacific Ocean, roughly following the 180° line of longitude and deviating to pass around some territories and island groups. Crossing the date line eastbound decreases the date by one day, while crossing the date line westbound increases the date. Geography Circumnavigating the globe People traveling westward around the world must set their clocks: *Back by one hour for every 15° of longitude crossed, and *Forward by 24 hours upon crossing the International Date Line. People traveling eastward must set their clocks: *Forward by one hour for every 15° of longitude crossed, and *Back by 24 hours upon crossing the International Date Line. Failing to do this would make their time inaccurate to the local time. The Arab geographer Abulfed ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
180th Meridian
The 180th meridian or antimeridian is the meridian (geography), meridian 180° both east and west of the prime meridian in a Geographic coordinate system, geographical coordinate system. The longitude at this line can be given as either east or west. On Earth, these two meridians form a great circle that divides the earth into the Western Hemisphere, Western and Eastern Hemispheres. The antimeridian mostly passes through the open waters of the Pacific Ocean, but also across land in Russia, Fiji, and Antarctica. An important function of this meridian is its use as the basis for the International Date Line, which snakes around national borders to maintain date consistency within the territories of Russia, the United States, Kiribati, Fiji and New Zealand. Starting at the North Pole of the Earth and heading south to the South Pole, the 180th meridian passes through: The meridian also passes between (but not particularly close to): *through the Aleutian Islands, Aleutian Isla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
176th Meridian East
The meridian 176° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Pacific Ocean, New Zealand, the Southern Ocean, and Antarctica to the South Pole. The 176th meridian east forms a great circle with the 4th meridian west. From Pole to Pole Starting at the North Pole and heading south to the South Pole, the 176th meridian east passes through: : See also * 175th meridian east The meridian 175° east of Greenwich is a line of longitude that extends from the North Pole across the Arctic Ocean, Asia, the Pacific Ocean, New Zealand, the Southern Ocean, and Antarctica to the South Pole. The 175th meridian east forms a gre ... * 177th meridian east {{geographical coordinates, state=collapsed e176 meridian east ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
