Atlantic South Current

The open waters of the South Atlantic lie in the basin between Africa and South America. From the age of oceanic exploration, this sea carried expanding trade and the violence of the slave traffic. Columbus reached the Americas in 1492, and Vasco da Gama reached India in 1498 by sailing around the Cape of Good Hope. In 1500, Pedro Álvares Cabral’s expedition to India was carried by the South Atlantic Gyre to Brazil. These voyages opened routes that joined Europe, Africa and the Americas.

The basin around those routes had formed during the Early Cretaceous breakup of West Gondwana. The Mid-Atlantic Ridge then follows the spreading boundary between the South American and African plates, dividing the deep ocean into eastern and western halves. Secondary ridges separate its basins, while the Walvis Ridge and Rio Grande Rise obstruct currents. Transform faults cut through the main ridge, allowing deep water to move between the divided basins.

At the surface, the anti-cyclonic subtropical gyre turns counter-clockwise. South Atlantic Central Water originates there, Antarctic Intermediate Water forms near the Drake Passage and the Falkland Islands, and both receive some contribution from the Indian Ocean. North Atlantic Deep Water moves south beneath the thermocline. From the sixteenth through the nineteenth centuries, the Atlantic remained central to the slave trade and the Columbian exchange. Those human movements occurred across a basin already organized by currents, ridges and layered water masses.