The ocean and sea are two large bodies of water, however there are some distinct differences between them. The ocean is the larger of the two and covers more than 70% of the Earth’s surface. It is divided into five distinct and separate bodies of water, the Pacific, Atlantic, Indian, Arctic, and Southern Oceans. Seas are smaller than oceans and are usually located where the land and ocean meet. They are typically partially enclosed by land and are connected to the ocean by a strait or channel. The Mediterranean Sea is one example of a sea.
The ocean is much deeper than a sea with depths of over 12,000 meters and contains a much greater variety of marine life. The ocean is home to a wide array of sea creatures, from massive whales to microscopic plankton. Seas usually have a much shallower depth, usually less than 1000 meters, and usually contain a fewer variety of marine life. Additionally, seas are often more prone to changes in temperature and salinity than oceans.
Overall, oceans are much larger and deeper than seas and contain a much greater variety of marine life.