How do marine animals live near the surface of the ocean?

Answer 1

The surface of the ocean is filled with phytoplankton. Phytoplankton are primary producers and entire marine life is basically depends on these producers. Hence marine animals live near the surface of the ocean for food, oxygen and sunlight.

Answer 2

Most organisms are either directly or indirectly dependent on photosynthesis. Photosynthesis is the process where plants use the energy from sunlight to convert carbon dioxide and water into sugars and oxygen. Most organisms, not only marine organisms are either herbivores or carnivores that feed on herbivores and herbivores need plants to feed. Since the surface zone of oceans and lakes is the layer where most of the sunlight frequencies still penetrate, it is there where most plants grow. Where there are many plants there are many herbivores that feed on plants and ultimately carnivores can live there, because this is where most of there prey can be found.