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Darwin Mounds is a large field of undersea sand mounds situated off the north west coast of Scotland〔(Scottish Government Press Release on EU Protection of the Darwin Mounds )〕 that were first discovered in May 1998. They provide a unique habitat for ancient deep water coral reefs and were found using remote sensing techniques during surveys funded by the oil industry and steered by the joint industry and United Kingdom government group the Atlantic Frontier Environment Network (AFEN) (Masson and Jacobs 1998). The mounds were named after the research vessel, itself named for the eminent naturalist and evolutionary theorist Charles Darwin. The mounds are located around 1,000 m (3,280 feet) below the surface of the North Atlantic ocean, approximately north-west of Cape Wrath, the north-west tip of mainland Scotland.〔(UK Deep Sea Image and Video Library )〕 There are hundreds of mounds in the field, which in total cover approximately 100 km². Individual mounds are typically circular, up to 5 m high and 100 m wide. Most of the mounds are also distinguished by the presence of an additional feature referred to as a 'tail'. The tails are of a variable extent and may merge with others, but are generally a teardrop shape and are orientated south-west of the mound. The mound-tail feature of the Darwin Mounds is apparently unique globally.〔(Biogenic reefs - cold water corals )〕 ==Composition== The mounds are mostly sand, currently interpreted as 'sand volcanoes'. These features are caused when fluidised sand 'de-waters' and the fluid bubbles up through the sand, pushing the sediment up into a cone shape. Sand volcanoes are common in the Devonian fossil record in UK, and in seismically active areas of the planet. In this case, tectonic activity is unlikely; some form of slumping on the south-west side of the undersea (Wyville-Thomson) Ridge being a more likely cause. The tops of the mounds have living stands of Lophelia and blocky rubble (interpreted as coral debris). The mounds provide one of the largest known northerly cold-water habitats for coral species. The mounds are also unusual in that Lophelia pertusa, a cold water coral, appears to be growing on sand rather than a hard substratum. Prior to research on the mounds in 2000, it was thought that Lophelia required a hard substratum for attachment. The deep-water coral systems located upon the mounds, are especially fragile. Unlike shallow-water coral reefs, they are not adapted to cope with minor disturbances such as wave action. The mounds also support significant populations of the xenophyophore ''Syringammina fragilissima''. This is a giant single-celled organism (a protozoan) that is widespread in deep waters, but occurs in particularly high densities on the mounds and the tails. Individual xenophyophores can grow to be larger than 20 cm and are often very fragile. The corals themselves provide a habitat for a wide diversity of other marine life including sponges, worms, crustaceans and molluscs. Among these starfish, sea urchins and crabs. Various fish have been observed, including blue ling, roundnose grenadier, and the orange roughy. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Darwin Mounds」の詳細全文を読む スポンサード リンク
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