Gyre

A Gyre is a naturally occurring vortex of wind and currents that rotate in a clockwise direction in the northern hemisphere and counter-clockwise in the southern hemisphere.

As massive quantities of marine debris circulate within currents across the globe, these create a whirlpool effect, whose vortex moves more slowly at the center and that is where marine plastic debris collects.

There are 5 major Gyres in the oceans worldwide, the North Atlantic, South Atlantic, North Pacific, South Pacific, and Indian Ocean gyres.

Wikipedia