A current is something that runs or flows . The Marine , meanwhile, is linked to sea : a mass of salt water. The idea of sea current, in this way, refers to the shallow movement of sea water .

Marine currents have various causes. The action of wind , the movement of rotation what the planet does land and the characteristics of the coasts These are some of the reasons that generate the existence of sea currents.
Importantly, marine currents involve not only displacements horizontal of the Water , but also vertical . Several decades ago, researchers discovered that the marine currents of the planet are structured in three dimensions:
* on the one hand, horizontal movements are noticed on the surface that mainly involve the inertia generated by the rotation of the Earth and the wind;
* vertical movements, meanwhile, alter the effects of rotation terrestrial because of the configuration that have the coasts and the submarine relief, so that a centrifugal force is produced that tends to concentrate, so to speak, the oceanic level over the entire circumference of Ecuador.
We must clarify what is known as centrifugal force , in accordance with the provisions of the mechanics Newtonian and the classic, to a fictitious force that occurs in the description of the movement that a body makes in a reference system that is rotating. It is also possible to define this concept as the apparent force that an observer warns in which Newton's laws of motion that are also in a rotating reference system are not applied.
On the other hand, it can be differentiated between different kinds of currents according to their characteristics. The cold sea currents , as the name suggests, they involve the displacement of waters that are at low temperatures. They are due to the rotational movement of the land and they develop from east to west by the rise of cold water that comes from very deep areas. The Humboldt stream , which is also known as Peru stream , is an example of cold current. The German Alexander von Humboldt It was he who described this sea current for the first time.
The warm sea currents Instead, they originate in the intertropical region, being born on the east coast and moving in the opposite direction to the rotation of the planet . The Gulf Stream , originated in the Gulf of Mexico , is a warm current.
The ocean currents , on the other hand, they register a constant movement because they are due to the terrestrial rotation, unlike the swell currents (related to wind) and tidal currents (linked to the attraction exerted by the Moon ), among others whose displacements vary.
One of the utilities that human beings have found in marine currents is the extraction of Energy , especially in the deepest areas, and for this he has been developing specific devices for a long time. It is necessary to clarify that This process involves a very high economic investment , which includes the manufacture of machinery, its installation and the inevitable maintenance tasks.
To offset these costs, the Polytechnic University of Madrid presented at the beginning of the year 2018 a series of designs and procedures that promise considerable savings. In addition to Spain, another country that is working on obtaining energy from sea currents is Canada, where there are already several experimental parks with first generation devices, which are placed in the background from sea.
Some experts point out that about 80% of this energy is beyond 40 meters of depth , and that is why the production of extraction devices is so expensive.