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Mudflats or mud flats, also known as tidal flats, are coastal wetlands that form when mud is deposited by tides or rivers. They are found in sheltered areas such as bays, bayous, lagoons, and estuaries. Mudflats may be viewed geologically as exposed layers of bay mud, resulting from deposition of estuarine silts, clays and marine animal detritus. Most of the sediment within a mudflat is within the intertidal zone, and thus the flat is submerged and exposed approximately twice daily. In the past tidal flats were considered unhealthy, economically unimportant areas and were often dredged and developed into agricultural land.〔(Dredging Indian River Lagoon Wetlands 1920 - 1950s )〕 Several especially shallow mudflat areas, such as the Wadden Sea, are now popular among those practising the sport of mudflat hiking. On the Baltic Sea coast of Germany in places, mudflats are exposed not by tidal action, but by wind-action driving water away from the shallows into the sea. These wind-affected mudflats are called ''windwatts'' in German. ==Ecology== Tidal flats, along with intertidal salt marshes and mangrove forests, are important ecosystems.〔(Tidal flat habitats )〕 They usually support a large population of wildlife, and are a key habitat that allows tens of millions of migratory shorebirds to migrate from breeding sites in the northern hemisphere to non-breeding areas in the southern hemisphere. They are often of vital importance to migratory birds, as well as certain species of crabs,〔(Mud crab (Scylla serrata) culture in tidal flats with existing mangroves )〕 mollusks and fish.〔(Manko - Tidal Flat, Mangrove Forest )〕 In the United Kingdom mudflats have been classified as a Biodiversity Action Plan priority habitat. The maintenance of mudflats is important in preventing coastal erosion. However, mudflats worldwide are under threat from predicted sea level rises, land claims for development, dredging due to shipping purposes, and chemical pollution. In some parts of the world, such as East and South-East Asia, mudflats have been reclaimed for aquaculture, agriculture, and industrial development. For example, around the Yellow Sea region of East Asia, more than 65% of mudflats have been destroyed over the past 50 years.〔 / 〕 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「mudflat」の詳細全文を読む スポンサード リンク
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