Some scientists believe that suspended matter in the sea is responsible for its blue color. Wind is the most common cause of surface waves. The longer the distance a wind blows, the stronger it is, and the bigger the waves. As wind blows over the ocean, it tries to pick up some of the water. Because the surface of the water can not move, it rises.
Gravity pulls the wave pack down into the ocean.
However, the water now has momentum. Water pressure from below pushes the water back up, and the cycle starts again. Significant sunlight can only penetrate 100 meters freely. Learn more about the ocean light zone. There is really only one big ocean.