There are two types of ocean currents: surface currents, which comprise 10% of ocean water in the upper 400m, and deep water currents, which make up 90% of ocean water. Ocean currents are driven by primary forces like solar heating, winds, gravity, and the Coriolis effect, as well as secondary forces that influence current direction. The Coriolis effect causes currents to veer to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. Gyres are formed by the interaction of winds and the Coriolis effect, creating circular ocean currents.