By Sid Perkins
The hallmarks of rotation are written all over the ocean. Huge currents flowing past islands and peninsulas generate enormous swirls in their wake, occasionally casting off giant whirlpools. Currents meandering across the open ocean can also shed massive, long-lasting eddies. Just as the atmosphere’s large- and small-scale motions mix the air, the ocean’s hierarchy of eddies blends cold waters with warm, the nutrient-rich with the nutrient-poor, and the salt-laden with fresher waters.
In the process, these massive swirls–many of them hundreds of kilometers across–transport some of the ocean’s heat from tropical climes to higher latitudes and create biological oases vast enough to be visible from space. What’s more, eddies can influence weather across a wide region, and their currents can have effects ranging from disrupting operations at deep-sea oil platforms to influencing the outcomes of long-distance yacht races.