Why is water in the ocean usually layered?
Because the densest water sinks, the ocean is usually layered or stratified, with the densest water on the bottom and the least dense water at the surface. Deep water is normally cold and dense, whereas surface water is relatively warm and “light.” 31. Describe the three layers of the ocean. The ocean is made up of three principal layers: the surface layer, the intermediate layer, and the deep and bottom layers. The surface layer is also known as the mixed layer. It is usually 100 to 200 m thick. Much of the time the surface layer is mixed by wind, waves, and currents. The intermediate layer lies below the surface layer to a depth of around 1,500 m. The main thermocline, a zone of transition between warm surface water and the cold water below, lies in the intermediate layer. Below about 1,500 m lie the deep and bottom layers. The water in these layers is uniformly cold, typically less than 4°C (39°F). 32. Why does ocean water sometimes overturn? Occasionally surface water becomes dense
