Home > Encyclopedia of Science > Ocean Zones

• Water depth versus light penetration
• The benthic realm
• Words to Know
• The pelagic realm
• Recent discoveries

Ocean zones are layers within the oceans that contain distinctive plant and animal life. They are sometimes referred to as ocean layers or environmental zones. The ocean environment is divided into two broad categories, known as realms: the benthic realm (consisting of the seafloor) and the pelagic realm (consisting of the ocean waters). These two realms are then subdivided into separate zones according to the depth of the water.

Water depth versus light penetration

Sunlight obviously cannot penetrate beyond a certain depth in the ocean. Some organisms...