1. Chapter 5

2. Exploring the Ocean People have studied the ocean since ancient times, because the ocean provides food and serves as a route for trade and travel. Modern scientists have studied the characteristics of the ocean’s waters and the ocean floor. clip 1clip 1

3. Exploring the Ocean Floor sonar (SOund NAvigation and Ranging) – a major advance in floor mapping which uses sound waves to calculate the distance to an object. clip 2clip 2

4. Features of the Ocean Floor If you could travel along the ocean floor, you would see: the continental shelf gently sloping, shallow area of the ocean floor that extends outward from the edge of a continent the continental slope the steep edge of a continental shelf the abyssal plain the smooth, nearly flat region of the ocean floor the mid-ocean ridge a continuous range of mountains that winds around Earth Trench a steep sided canyon in the ocean floor Seamount – a mountain on the ocean floor, completely under water Complete Diagram

5. Earth’s Layers The Earth consists of the following layers: the core – Earth’s center the mantle – the thick molten layer between the core and the crust the crust – the thin, rocky, outer layer of Earth

6. Earth’s Plates plates – the pieces of Earth’s crust, along with parts of the upper mantle Plate movements have shaped many of the most dramatic features of Earth, both on land and under the ocean. seafloor spreading – a process by which new rock is added to the ocean floor along the boundary between diverging plates (clip 3)(clip 3) Seafloor spreading is slowly causing Earth’s plates to move together.

7. Seafloor Spreading

8. Ocean Zones Ocean zones include: the intertidal zone the highest high-tide line on land the neritic zone Extends from the low-tide line out to the edge of the continental shelf the open-ocean zone the ocean beyond the edge of the continental shelf

9. Life in the Ocean Scientists classify marine organisms according to where they live and how they move. Plankton – tiny algae and animals that float in the water and are carried by waves and currents Nekton – free-swimming animals that can move throughout the water column Benthos – organisms that inhabit the ocean floor

10. Ocean Food Webs Food web – All of the feeding relationships that exist in a habitat. Note the importance of Phytoplankton (algae) and zooplankton (microscopic animals) at Its base.

11. Intertidal Zone OrganismsOrganisms that live in the shallow waters of the rocky intertidal zone must be able to tolerate the constant pounding of the waves and changes in both salinity and temperature. They must also withstand periods of being underwater (wet) and periods of being exposed to the air. (dry) clip 4clip 4

12. Neritic Zone The somewhat shallow, warm water over the continental shelf receives sunlight and a steady supply of nutrients washed from the land into the ocean. The light and nutrients enable large plant- like algae to grow. A large variety of plants and animals are found here. This zone houses the most life overall of all the zones.

13. Where River Meets Ocean Estuaries – coastal inlets or bays where fresh water from rivers mixes with the salty ocean water. Along the coasts of the United States, most wetlands are either mangrove forests or salt marshes. Mangrove forests are short, gnarled trees that grow well in brackish water. Salt marshes consist of mud and cord-grass.

14. Coral Reef A coral reef is another type of diverse habitat found in the neritic zone.coral reef Coral reefs can form only in shallow, tropical ocean waters.

15. Life in a Kelp ForestKelp Forest Kelp forests grow in somewhat cold neritic waters where the ocean has a rocky floor.clipclip

16. Conditions in the Open OceanOpen Ocean The open ocean differs from the neritic zone in two important ways. First, only a small part of the open ocean receives sunlight. Second, the water has fewer nutrients. The three open ocean zones: 1. The Surface Zone (Sunlight) 2. The Transition Zone (Twilight) 3. The Deep Zone(Midnight) Bioluminescence – the production of light by living things

17. Hydrothermal Vents Hydrothermal vents are places where ocean water sinks through cracks in the ocean floor and is heated by the underlying magma. The heated water then rises again through the cracks. Water is filled with minerals.clipclip

18. Resources From the Ocean People depend heavily on fishes and other ocean organisms for food. Ocean organisms also provide materials that are used in products such as detergents and paints. Aquaculture – the farming of saltwater and freshwater organisms

19. Nonliving Resources Some nonliving ocean resources include: Water Fuels (oil) Minerals Nodules – black lumps formed when metals concentrate around pieces of shell

20. Ocean Pollution Although some ocean pollution is the result of natural occurrences, most pollution is related to human activities. It is important for humans to protect Earth’s oceans. clip