Agulhas

In a related study, the researchers also analyzed 41 years of sea surface temperature data and 33 years of wind records to learn about the history of upwelling events in the Indian Ocean’s Agulhas Current and the East Australian Current — particularly when they had a large death toll in animals like sharks, squid and manta rays.

These turtles were likely sucked in by the warm Indian Ocean Agulhas Current, carried around the tip of South Africa and spat out in the cold waters of the Atlantic Ocean near Cape Town.

In the case of the Agulhas Current, researchers in 2016 reported that since the 1990s its flow had grown broader and was more likely to create potent eddies.

They found that upwelling events at several spots in the Agulhas Current have grown more frequent and more intense, lasting longer and reaching lower temperatures.

Their focus fell on the Agulhas Current, a fast-moving river of ocean water on the western edge of the Indian Ocean that sweeps southward along the coasts of Mozambique and South Africa.