North Atlantic Currents
The North Atlantic Ocean is dominated by the NORTH
EQUATORIAL CURRENT and the GULF STREAM SYSTEM.
NORTH EQUATORIAL
CURRENT.—  The North
Equatorial Current is located in the trade wind belt (zona) of the North
Atlantic Ocean. The chief sources of the flow are
the northeasterly currents off the west coast of northwestern Africa. These
currents of water of relatively high density and
low temperature are an extension of the North Atlantic Current. They help lower
the temperatures along the northwest coast of
Africa. The temperatures near the coast are further lowered by UPWELLING.
Upwelling of ocean water is a process by which winds push surface
water away from the coast. Colder subsurface water then moves up and replaces
the surface water. In the Northern Hemisphere, upwelling is common where
the wind blows parallel to the coast, with the coast
on the left side of the wind. The upwelling process affects only the upper
layers of the ocean (the maximum depth being about
150 fathoms or 900 feet).
 As
the North Equatorial Current flows westward north of the equator, the South
Equatorial Current crosses the equator and joins it in
the western North Atlantic Ocean. Consequently, that part of the North
Equatorial Current that enters the Caribbean Sea
has water that is a mixture of waters from the North Atlantic Ocean and South
Atlantic Ocean.
ANTILLES CURRENT. —The
Antilles Current is the western extension of the North Equatorial Current. It
flows along the northern side of the Greater
Antilles. It carries water that is virtually the same as that of the Sargasso
Sea (a portion of the middle North Atlantic Ocean).
GULF STREAM SYSTEM.
—The Gulf Stream system begins in the Florida Straits and flows northward and
eastward along the east coast of the United States.
This system, along with the Kuroshio System of the western Pacific, is the
fastest of all the ocean currents. It moves with
speeds of 25 to 75 miles per day or roughly 1 to 3 knots. The Gulf Stream system
is made up of three currents: the FLORIDA CURRENT,
GULF STREAM, and NORTH ATLANTIC CURRENT.
 Florida
Current. —The Florida current extends from the Florida Straits to Cape
Hatteras. Much of the flow is derived from the Caribbean
Sea by way of the Yucatan Channel; the water from the Yucatan Channel takes the
shortest route to the Florida straits rather than
making a long sweep through the Gulf of Mexico. The Florida Current is also fed
by the Antilles Current.
Oceanographers believe that the energy of the Florida
Current comes from the difference in the levels of the water in the Gulf of Mexico and the water adjacent to the Florida coast, the
waters in the Gulf being higher. The difference in the two levels is due to the prevailing winds which result in the piling up of
water in the Gulf of Mexico.
Gulf Stream. —The Gulf
Stream is the middle portion of the Gulf Stream System. It begins near Cape
Hatteras and continues north-ward to the vicinity
of the Grand Banks off Newfoundland. To the right of the Gulf Stream is the
Sargasso Sea portion of the North Atlantic Ocean,
and to the left are coastal and slope waters.
 North
Atlantic Current. —The North Atlantic Current begins off the Grand Banks,
where the Gulf Stream begins to fork. It consists
of northerly and easterly currents terminating in subsidiary currents. One of
the major subsidiaries is the IRMINGER CURRENT, which flows
westward off the southern coast of Iceland. Another is the NORWEGIAN
CURRENT. It flows beyond the Norwegian Sea into
the polar seas. Other branches of the North Atlantic Current, turning southward,
end in huge eddies off the coast of Europe and in
the relatively cold CANARIES CURRENT off the
northwest coast of Africa.
Note:
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 Area eccezionalmente pescosa dell'oceano Atlantico settentrionale,
caratterizzata da acque poco profonde, situata al largo della Terranova
sudorientale (Canada); è costituita da una serie di rilievi sottomarini
che s'innalzano dalla piattaforma continentale e si estende per circa 560
km, con una profondità generalmente compresa tra i 37 e i 183 m. La
fredda corrente del Labrador attraversa buona parte della zona, mentre la
calda corrente del Golfo scorre lungo la parte orientale della zona
stessa: l'unione delle due correnti, insieme alla scarsa profondità
dell'acqua, fornisce un ambiente favorevole per il plancton, che
costituisce l'alimento principale dei pesci. Per questa ragione da più di
mezzo secolo Grand Banks è una delle aree oceaniche più pescose del
mondo, con varie specie di pesce: merluzzo, eglefino, aringa e sgombro.
Nel XX secolo, tuttavia, l'eccessivo sfruttamento delle risorse ittiche ha
reso necessari dei provvedimenti per proteggere le riserve, tra cui una
netta diminuzione dei quantitativi pescabili. Ciò ha provocato delle
tensioni internazionali: un esempio è costituito dall'incidente avvenuto
nel marzo 1995, quando le autorità canadesi sequestrarono un
motopeschereccio spagnolo che aveva superato la quota stabilita
dall'Unione Europea per l'ippoglosso (halibut) della Groenlandia. La
zona è spesso avvolta da una fitta nebbia.
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