Two large warm water eddies are swirling to the north of the Gulf Stream current in this satellite image. Blue colors show cooler water, while yellow and orange colors show warmer water.
Click on image for full size
Courtesy of the Ocean Remote Sensing Group, Johns Hopkins University Applied Physics Laboratory

The Swirling Water of Ocean Eddies

Sometimes water spins away from a surface ocean current. This makes an eddy.

The center of some eddies is cooler water while the center of others is warmer water. There isnít as much marine life or as many nutrients in warm water eddies as there is in cold water eddies.

Eddies are made when a bend in a surface ocean current makes a loop that breaks away from the current. The Coriolis effect makes eddies to rotate in different directions in the different hemispheres. Cold water eddies to rotate counterclockwise and warm water eddies to rotate clockwise in the Northern Hemisphere. In the Southern Hemisphere it is just the opposite. Once an eddy forms, the swirling waters last for at least a few months.

The image at the left, taken from a satellite high in the sky, shows two large circles above the Gulf Stream current in the Atlantic Ocean. These are eddies. In this image, surface water is colored depending on its temperature. Cooler water is shown with blue and purple and orange and yellow show warmer water. The orange color of these eddies means that they are warm water eddies. The Gulf Stream can have some of the largest and most well defined eddies in the world.

Last modified January 8, 2010 by Randy Russell.

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