The two largest oceans on the planet, the Atlantic and the Pacific, seem mostly isolated; the continents strangle the open waters in Tierra de Fuego and South Africa near the South Pole. Scientists are increasingly confident that both oceans are more connected than it looks. They intrigued by the mutual influence of two powerful stream jets in the oceans: the Gulf Stream and the Agulhas Current.
The Agulhas Current flows in the Indian Ocean along the South African coast. Westerly winds block the exchange of water between the Indian Ocean and the Atlantic. The Agulhas Current abruptly turns back into the Indian Ocean southwest of Cape Town. Rings of water with diameters of hundreds of kilometres, the “Agulhas Rings”, are cut off at intervals of 3 to 4 months. The Agulhas Rings carry warm and saline waters from the Indian Ocean into the Atlantic.
The prevailing currents transport this salty water northward. It is speculated that they prevent the freshening process due to enhanced precipitation and the ice melting and thus stabilize the Gulf Stream in the North.
The westerlies have shifted southward as part of the climate change. This has widened the corridor south of Africa for the inflow of water into the Atlantic. The influence of the Agulhas Current ot the Gulf Stream may now be stronger than ever.