In the Southern Hemisphere, which direction do gyres rotate?

• A. Counterclockwise
• B. Clockwise
• C. They don't rotate
• D. Random

Answer: (A)

Gyres rotate due to the Coriolis effect, which deflects moving water to the left in the Southern Hemisphere. That leftward deflection causes surface currents to curve in a way that the circulation runs counterclockwise when viewed from above. Wind patterns and Ekman transport drive water toward the centers of the gyres, completing the circular flow. In the Northern Hemisphere, deflection is to the right, producing clockwise gyres, so the hemispheres rotate in opposite directions. Therefore, in the Southern Hemisphere the gyres rotate counterclockwise.