Major surface currents of the world's oceans. Subsurface currents also move vast amounts of water, elipsis
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An ocean current is continuous, directed movement of ocean water. Ocean currents are rivers of hot or cold water within the ocean. The currents are generated from the forces acting upon the water like the planet rotation, the wind, the temperature and salinity (hence isopycnal) differences and the gravitation of the moon. The depth contours, the shoreline and other currents influence the current's direction and strength. The meshing of all of these characteristics is what creates the great flow of the global conveyor belt which plays a dominant part in the climate of many of the Earth’s regions.
Deep ocean currents are driven by density and temperature gradients. Thermohaline circulation, also known as the ocean's conveyor belt, refers to the deep ocean density-driven ocean basin currents. These currents, which flow under the surface of the ocean and are thus hidden from immediate detection, are called submarine rivers. These are currently being researched by a fleet of underwater robots called Argo. Upwelling and downwelling areas in the oceans are areas where significant vertical movement of ocean water is observed.
Surface currents make up about 10% of all the water in the ocean. Surface currents are generally restricted to the upper 400 meters of the ocean. The movement of deep water in the ocean basins is by density driven forces and gravity. The density difference is a function of different temperatures and salinity. Deep waters sink into the deep ocean basins at high latitudes where the temperatures are cold enough to cause the density to increase. The main causes of currents are: solar heating, winds and gravity.
Ocean currents are measured in Sverdrup with the symbol Sv, where 1 Sv is equivalent to a volume flow rate of 106 cubic meters per second.
In addition, temperature of the water plays a big role. The warmer the water is the less salt it has therefore it is less dense and this water will rise up towards the surface. Cooler water is much denser because of the high concentration of salt within the water and it sinks to the bottom. This cycle of warming and cooling is what creates the mixing and therefore the driving currents system. The cooler water, in addition to sinking, will make its way towards the equator to gather heat where then, in turn, it will make its way towards the poles to cool completing the cycle. This is the basic mechanism by which ocean currents are activated.
Another section of the world’s oceans which is being researched and has had a recent major scientific discovery is the southern oceans. At a certain depth within this marine region all of the oceans are connected, have formed a ‘supergyre,’ and have an impact on each other.
Ocean currents are also very important in the dispersal of many life forms. A dramatic example is the life-cycle of the eel.
Ocean currents are important in the study of marine debris, and vice versa.
One of those systems which would greatly be affected by a change in ocean currents would be coral reefs. Coral reefs are some of the most fascinating environments on the planet.
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Wipo Publishes Patent of Zhao Gaoyuan, GAO Kejun for "Floating-Type Ocean Current Combination Power Generation Device" (Chinese Inventors)
Nov 06, 2012; GENEVA, Nov. 6 -- Publication No. WO/2012/146197 was published on Nov. 1. Title of the invention: "FLOATING-TYPE OCEAN CURRENT...