Gyres in the Northern Hemisphere and the Southern Hemisphere primarily differ in their direction of rotation due to the Coriolis effect. In the Northern Hemisphere, gyres rotate clockwise, while in the Southern Hemisphere, they rotate counterclockwise.
However, with respect to the options given, the most relevant difference is related to the movement of warm and cold water. Specifically, gyres generally move warm water from equatorial regions to polar regions in both hemispheres.
The correct answer from the choices provided is:
They move warm water from equatorial regions to polar regions.
This is applicable to both hemispheres, but it highlights the essential role of gyres in ocean circulation patterns.