Ocean Zones

Objectives

• understand that the ocean has several different zones
• understand that the requirements for survival are different in each zone
• create a mural showing the diversity of ocean life

Vocabulary

• tidal zone
• pelagic zone
• abyssal zone
• plankton

Background

The ocean is an enormous environment. Along the shores of the continents it is shallow, but offshore it can be deeper than the highest mountain is on earth. Scientists refer to the different parts of the ocean as zones. Conditions in these zones can be very different, and the animals that live in each zone are different, too.

Life near shore in the tidal zone is tough. Animals here must be able to hold on tight to rocks or bury in the protection of the sand to keep from being washed away when the tide comes in. When the tide goes out, some of these animals follow the water. Others close up tight and hold water in their shells. All must be well protected with spiny skins, camouflage or shells since their enemies may come from either the land or the sea.

The open ocean, or pelagic zone, is for swimmers, floaters and drifters that never touch the bottom. Open ocean dwellers include some of the largest and fastest ocean animals, like sharks, whales and tuna. They also include some of the slowest and smallest, like the microscopic plants and animals, called plankton, that are carried along by the ocean currents.

Some of the strangest creatures live in the icy darkness of the deep sea, the abyssal zone. Hundreds of feet below the ocean surface, the sun never shines. Some animals, like the lanternfish, make their own light to attract food and scare off predators. There are no plants, so food is scarce. Many deep sea fish, like the gulper eel, have giant mouths and fang-like teeth to capture and swallow a meal of any size, even one larger than they are.

At the South Caicos research site, SFS students identify and study zones on the reef: the shallow lagoon behind the reef; the crest, where waves break; the outer reef edge; and the deep reef. Their studies report on the different types of animals that live in each zone.

Materials

• large roll of paper
• markers
• paint
• reference books
• photographs of ocean animals

Activity

Have students create a mural showing ocean zones and the diversity of ocean life.

1. Draw a simple cross section of an ocean on a large roll of paper. Include the shallows near shore, the open ocean and the deep sea. This will be the base for the mural.
2. Discuss the three ocean zones. Ask students: How do these zones differ? What kinds of plants and animals live in each zone? How does a sandy beach differ from a rocky tidal zone?
3. Have students use reference books to create a list of plants and animals that live in each zone.
4. Have students illustrate each zone on the mural. Students may draw, paint and/or use collage techniques.
5. Display the mural. Have students describe their work.

• Reverse the ocean zones activity. Start with an animal or plant and ask students to predict the zone in which it would live.

• What is the history of ocean exploration? Have students write a report on a famous ocean scientist or historic expedition. Some examples include the HMS Challenger Expedition; Charles Darwin and the voyage of the HMS Beagle; Rachel Carson; Jacques Cousteau; Bob Ballard and the deep sea voyages of Alvin and Jason Jr.; Sylvia Earle; and Eugenie Clark.

• If you have a local dive shop near your home, arrange to visit it. Ask the owner or salesperson to demonstrate scuba diving equipment and answer students’ questions about diving.