The ocean’s largest and most permanent currents make up the systems of currents known as gyres. There are 5 major gyres. They are the North and South Pacific Subtropical Gyres, the North and South Atlantic Subtropical Gyres, and the Indian Ocean Subtropical Gyre. More recently, the term “gyre” has also been used to describe the collections of plastic waste and other debris found in high concentrations in certain parts of the world’s oceans.