The division of ocean can be done :

1. Vertically - based on penetration of light and depth, ocean zone is divided in to two zone. Photic zone, which is up to 200 meters below water level and Aphotic zone, which is from 200 to 10000 meters below water level.
2. Horizontally - ocean is divided in to three zones based on distance from shore. Intertidal zone, coastal ocean and open ocean.