The part of the ocean that is out of sight of land. Most of the ocean is open ocean, but it is often referred to as the 'marine desert' because there is a lot less life living there than in shallow seas.
A rocky shore is the area where the sea tide moves up and down, exposing solid rock when the tide is out and covering it with water when it is in. Rocky shores are home to many different animals such as shellfish, birds, sea anemones, and crabs.
A long line of jagged rock, coral, or sand just above or below the surface of the ocean. An artificial reef is when a human-made structure creates a reef on the sea floor.