How Many Ocean Currents Are There?
There are many types of great ocean currents or drifts. They are caused by three main forces: the prevailing winds, the earth’s rotation and differences in the sea’s density. Winds exert drag or friction on the waves and cause surface currents. This is particularly noticeable in the belts of the westerlies and the trade winds. The rotation of the earth gives these currents circular movements. There is also a circular movement from the deeper layers of water to the surface where currents meet or diverge.
Water rich in nutrient
salts comes welling up from the depths of the ocean and stimulates the growth
of plant life in the surface layers. This abundance of plant food attracts
fish, and many great fishing grounds are situated along the paths of the ocean
currents. One of the most interesting currents is the warm Gulf Stream of the
Atlantic that gives western Europe and parts of eastern North America a
temperate climate. It begins in the westward-drifting waters traveling across
the Gulf of Mexico, passes through the straits of Florida and flows north-east
across the Atlantic. Although it is always comparatively warm, the temperature
does vary a few degrees from year to year.
Currents caused by differences in the density of sea water are usually under the surface and slow-moving. They are responsible for the general circulation of the deep layers of the ocean and are formed from the large volumes of ice-cold water pouring into the oceans from the polar regions. These plentiful supplies keep the temperature of the ocean low.
The major currents across the globe include the California and Humboldt currents in the Pacific, the Gulf Stream and Labrador currents in the Atlantic and the Indian Monsoon current in the Indian Ocean. The ocean currents can travel great distances, the Gulf Stream for example, starts in the Gulf of Mexico and eventually makes its way to Europe, travelling approximately 222 kilometres a day. The ocean currents transport large amounts of cold and warm water to various regions across the globe.
The oceans also alter
atmospheric conditions because of their ability to store huge quantities of
heat and moisture, thus affecting the weather systems. Ireland’s weather, for
example, is affected by the Gulf Stream current and its northern extension, the
North Atlantic Drift. This rapid current originates in Florida and transports
its warm waters to the north Atlantic affecting the climate of Western Europe.
These warm waters create a climate in parts of Europe that is significantly
warmer compared to other regions that lie on similar latitudes and stave off
potentially continuous sub-zero temperatures.
Warm currents increase the rainfall of the countries near which they flow. The warm air over the currents becomes heavily charged with moisture and condenses over the land as rain or snow. Ocean currents are important in the study of marine debris, and vice versa. These currents also affect temperatures throughout the world. For example, the ocean current that brings warm water up the north Atlantic to northwest Europe also cumulatively and slowly blocks ice from forming along the seashores, which would also block ships from entering and exiting inland waterways and seaports, hence ocean currents play a decisive role in influencing the climates of regions through which they flow.
Cold ocean water currents flowing from polar and sub-polar regions bring in a lot of plankton that are crucial to the continued survival of several key sea creature species in marine ecosystems. Since plankton are the food of fish, abundant fish populations often live where these currents prevail. Ocean currents can also be used for marine power generation, with areas off of Japan, Florida and Hawaii being considered for test projects.