Directions:
Read the article "Oceans Zones."
As one gazes across the vast surface of a rippling ocean, it's easy to think the ocean is all the same. Yet, sunlight causes the ocean to be different at different depths. There are three different ocean zones: the sunlight zone, the twilight zone, and the midnight zone. As one travels through these three zones, changes occur in visibility, temperature, and pressure.
Light streams through the top layer of the ocean. This area is called the sunlight zone. The sunlight zone goes from the surface of the ocean down to about 300 feet. The temperature ranges from 65° F at the surface to 56° F at 300 feet below the surface. Although the sunlight zone makes up only a small portion of the ocean, 90% of all known sea creatures are found here. This is the only zone that contains enough light to support plant life. When plants and animals die, they slowly drift towards the bottom of the ocean and become food for creatures found in the deeper zones.