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Upwelling is an oceanographic phenomenon that occurs when strong, usually seasonal, winds push water away from the coast, bringing cold, nutrient-rich deep waters up to the surface.Deep water nutrients consist of nutritional salts such as nitrates and phosphates, themselves the result of decomposition of the sea snow . When brought to the surface, these nutrients are processed by phytoplankton and combined with organic compounds such as dissolved CO2, using the energy of the sun through photosynthesis.
Upwellings therefore cause very high levels of productivity in phytoplankton compared to other areas of the ocean, and phytoplancton being the basic nutrient of most sea animals, these effects are propagated up the food chain.
Currently known regions of upwelling include coastal Peru, Arabian Sea, western South Africa, eastern New Zealand and the California coast, all very rich fishing grounds.
Localized upwelling may be due to deflection of deep currents by a seamount providing a nutrient rich island in otherwise low productivity ocean areas. These provide islands of life in such areas and are important to migrating species and human fishing. Upwelling can also occur when tropical cyclones stall over an area, moving at speeds of less than 5 mi/h (8 km/h). The churning of a cyclone eventually draws up cooler water from lower layers of the ocean. This causes the cyclone to weaken.
Upwellings also occur in other fluid environments, such as the magmaThis article is about the type of rock. For magmas in mathematics, see Magma (algebra). For the experimental jazz band, see Magma (band). For the computer algebra system, see Magma computer algebra system. For the EDA software company, see Magma Design Au in Earth's mantle or the plasmaFor the fluid portion of blood, see blood plasma; also, other uses. There is debate as to whether plasma is an individual state of matter or simply a type of gas. In physics and chemistry, plasma (also called an ionised gas is an energetic gas-phase state within a starFor alternate meanings see star (disambiguation Hubble Space Telescope of the Sagittarius Star Cloud in the Milky Way Galaxy. A star is any massive gaseous celestial body in outer space. Stars appear as shining points in the nighttime sky that twinkle bec. They are often a result of convectionFluid dynamics Convection is the transfer of heat by the motion of or within a fluid. It may arise from temperature differences either within the fluid or between the fluid and its boundary, or from the application of an external motive force. It is one o.
