Organic compound, chemical formula CH4, colourless, odourless gas that occurs in natural gas (called firedamp in coal mines) and from bacterial decomposition of vegetation in the absence of oxygen (including in the rumens of cattle and other ruminants and in the gut of termites). The simplest member of the paraffin hydrocarbons, methane burns readily, forming carbon dioxide and water if supplied with enough oxygen for complete combustion or carbon monoxide if the oxygen is insufficient. Mixtures of 5–14percnt methane in air are explosive and have caused many mine disasters. The chief source of methane is natural gas, but it can also be produced from coal. Abundant, cheap, and clean, methane is used widely as a fuel in homes, commercial establishments, and factories; as a safety measure, it is mixed with trace amounts of an odorant to allow its detection. It is also a raw material for many industrial materials, including fertilizers, explosives, chloroform, carbon tetrachloride, and carbon black, and is the principal source of methanol.
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Either of two large swamp trees (Taxodium distichum and T. ascendens; family Taxodiaceae) of the southern U.S. that are related to the sequoias. The hard red wood of cypress is often used for roofing shingles. The so-called deciduous cypress family (see deciduous tree) comprises 10 genera with 15 species of ornamental and timber evergreen trees, native to eastern Asia, Tasmania, and North America. The leaves on a single tree may be scalelike, needlelike, or a mixture of both. Both male and female cones are borne on the same tree. The Tasmanian cedar (Athrotaxis), Japanese cedar (Cryptomeria japonica), China fir (Cunninghamia lanceolata), umbrella pine (Sciadopitys verticillata), big tree, redwood, dawn redwood, and bald cypress are economically important timber trees in this family.
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Freshwater wetland ecosystem characterized by poorly drained mineral soils and plant life dominated by trees. Swamps have a sufficient water supply to keep the ground waterlogged, and the water has a high-enough mineral content to stimulate decay of organisms and to prevent the accumulation of organic materials. They are found throughout the world. Seealso marsh.
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Swamp and wildlife refuge, southeastern Georgia and northeastern Florida, U.S. It has an area of more than 600 sq mi (1,550 sq km). Located about 50 mi (80 km) inland from the Atlantic coast, it is bounded by the low, sandy Trail Ridge, which prevents direct drainage into the Atlantic. It has diverse and abundant wildlife. Exotic flowers, such as rare orchids, abound. In 1937 a large area of the swamp, almost all in Georgia, was made the Okefenokee National Wildlife Refuge.
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Wetland region, southeastern Virginia and northeastern North Carolina, U.S. Despite much lumbering and widespread destruction by fire, the area is still heavily wooded. About 30 mi (48 km) long and 10 mi (16 km) wide, it is home to many rare birds and numerous poisonous snakes. Noted for its fishing and hunting, it is traversed by the Dismal Swamp Canal, part of the Atlantic Intracoastal Waterway.
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A swamp is a wetland featuring temporary or permanent inundation of large areas of land, by shallow bodies of water. A swamp generally has a substantial number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The water of a swamp may be fresh water or salt water. A swamp is also generally defined as having no substantial peat deposits.
In North America, swamps are usually regarded as including a large amount of woody vegetation, but elsewhere this may not necessarily apply, such as in African swamps dominated by papyrus. By contrast a marsh in North America is a wetland without woody vegetation, or elsewhere, a wetland without woody vegetation which is shallower and has less open water surface than a swamp. A mire (or quagmire) is a low-lying wetland of deep, soft soil or mud that sinks underfoot.
Swamps are generally characterised by very slow-moving waters. They are usually associated with adjacent rivers or lakes. In some cases, rivers become swamps for a distance. Swamps are features of areas with very low topographic relief, although they may be surrounded by mountains.
Swamps were historically often drained to provide additional land for agriculture, and to reduce the threat of diseases born by swamp insects and similar animals. Swamps were generally seen as useless and even dangerous. This practice of swamp draining is nowadays seen as a destruction of a very valuable ecological habitat type of which large tracts have already disappeared in many countries.