Ocean current hemisphere due to imposed wind stresses. In these wind-driven currents, the Ekman spiral effect results in the currents flowing at an angle to the driving winds. In addition, the areas of surface ocean currents move somewhat with the seasons; this is most notable in equatorial currents. Deep ocean basins generally have a non-symmetric surface current, in that the eastern equatorward-flowing branch is broad and diffuse whereas the western poleward flowing branch is very narrow. These western boundary currents (of which the Gulf Stream is an example) are a consequence of the rotation of the Earth. Deep ocean currents are driven
Atlantic Ocean of the circumpolar region, near the Drake Passage and Falkland Islands. Both these currents receive some contribution from the Indian Ocean. On the African east coast the small cyclonic Angola Gyre lies embedded in the large subtropical gyre. The southern subtropical gyre is partly masked by a wind-induced Ekman layer. The residence time of the gyre is 4.4–8.5 years. North Atlantic Deep Water flows southerward below the thermocline of the subtropical gyre. The Sargasso Sea in the western North Atlantic can be defined as the area where two species of "Sargassum" ("S. fluitans" and "natans") float, an area wide and