This amazing site looks at the problem of plastic pollution, offers suggested solutions, and provides links to research on the 5 global gyres. Their mission is to encourage understanding about "plastic marine pollution through exploration, education, and action."
This National Geographic encyclopedia article offers a description of ocean gyres as well as key related vocabulary terms and a map showing gyres around the world.
The National Oceanic and Atmospheric Administration has diagrams and descriptions of our Earth's surface ocean currents, gyres, the Coriolis Effect and the effect of winds.