The ocean is very wide and very tall. The ocean has three zones the sunlight, twilight, and midnight zone. The sunlight zone starts at sea level and ends at 200m, the twilight zone starts at 200m and ends 1000m, last is the midnight zone which starts at 1000m and ends at 4000m. Each zone is very different.

             The coral reefs area part of the sunlight zone . Coral reefs can only form in warm, clear, salty water, and only in shallow water. Coral polyp starts its life after its parent coral. The polyp drift on the top of the of the ocean surface until it attack itself to a hard surface. As a young polyp grows it combines calcium and carbon dioxide to make a hard limestone cup around its soft body . The algae and the polyp are partners. The algae make oxygen and some other nutrients that the polyp needs, in return the polyp gives off carbon dioxide and substances that the algae needs. At night the polyp eats plankton drifting within the reach of their stinging, in the day it stays in the limestone cup its tentacles curl in over the top. The coral reef offers plenty of food, many places to hide and live.

             The second zone is the twilight zone. There the water pressure and the temperature drops quickly. Most of the sunlight has been absorbed by sunlight zone. The dim light gradually becomes dimmer as you go further. Plants cannot grow in this dim water. Animals who live here are in smaller numbers and there size is generally smaller. Some of these animals swim to the sunlight zone at night to eat. Others prey on other animals living in this deeper and dimmer zone. Still others survive by eating pieces of plants and animal remains that drift down form the sunlight zone.

             The last zone is called midnight zone. With water pressure can exceed 2 ton per square inch, the temperature of the water is near fresh water"s freezing point, and it is completely dark. Scientists think that only 1% of all ocean species live here.