A Gyre is a system of circulating currents in an ocean, caused by the Coriolis Effect.
There are five major gyres in the world's oceans:
- North Pacific Gyre
- South Pacific Gyre
- North Atlantic Gyre
- South Atlantic Gyre
- Indian Ocean Gyre
Because gyres are systems of circulating currents, they result in marine debris accumulation at their centers. The most famous example of this phenomenon is known as the Great Pacific Garbage Patch - a floating accumulation Marine Debris comprised largely of plastic trash located north of Hawaii.
An organization whose mission is to "conduct research and communicate about the global impact of plastic pollution in the world’s oceans and employ strategies to eliminate the accumulation of plastic pollution in the 5 subtropical gyres" is 5 Gyres.
In addition to the five major oceanic gyres, there are also smaller equatorial gyres in the Atlantic, Pacific, and Northern Indian Oceans.