What are ocean garbage gyres and how many exist?

The answer

There are five major oceanic gyres, large systems of circular currents formed by global wind patterns and Earth's rotation, and each accumulates floating debris. They are the North Pacific, South Pacific, North Atlantic, South Atlantic, and Indian Ocean gyres. The North Pacific gyre contains the largest garbage accumulation, but all five trap significant amounts of plastic and other waste. Together, an estimated 5 to 13 million metric tonnes of plastic enter the ocean annually, and once caught in a gyre, debris can circulate for decades, slowly breaking into smaller and smaller microplastic fragments.