Exploring the Oceans

1. Chapter 13 Exploring the Oceans Preview Section 1Earth’s Oceans Section 2The Ocean Floor Section 3Life in the Ocean Section 4Resources from the Ocean Section 5Ocean Pollution Concept Mapping

2. Chapter 13 Section1 Earth’s Oceans Objectives • List the major divisions of the global ocean. • Describe the history of Earth’s oceans. • Identify the properties of ocean water. • Describe the interactions between the ocean and the atmosphere.

3. Chapter 13 Section1 Earth’s Oceans Divisions of the Global Ocean • The largest ocean is the Pacific Ocean. • The other oceans, listed from largest to smallest, are: • the Atlantic Ocean • the Indian Ocean • the Arctic Ocean • the Southern Ocean

4. Chapter 13 Section1 Earth’s Oceans

5. Chapter 13 Section1 Earth’s Oceans How Did the Oceans Form? • About 4.5 billion years ago, there were no oceans. • Sometime before 4 billion years ago, water vapor in the atmosphere condensed and fell as rain. • The rain filled the deeper levels of Earth’s surface and the first oceans began to form.

6. Chapter 13 Section1 Earth’s Oceans How Did the Oceans Form?, continued • The shape of the oceans has changed over time.

7. Chapter 13 Section1 Earth’s Oceans Characteristics of Ocean Water • Dissolved Gases Nitrogen, oxygen, and carbon dioxide are the main gases dissolved in ocean water. • Solids Sodium chloride, or table salt, is the most abundant dissolved solid in the ocean. Other solids are also found in ocean water.

8. Chapter 13 Section1 Earth’s Oceans Characteristics of Ocean Water, continued • Salinity is a measure of the amount of dissolved solids in a given amount of liquid. • Changes in Salinity Climate and water movement affect salinity. Costal water in cool, humid places has a low salinity. Slow-moving bodies of water have higher salinity than other parts of the ocean do.

9. Chapter 13 Section1 Earth’s Oceans

10. Chapter 13 Section1 Earth’s Oceans Characteristics of Ocean Water, continued • Temperature Zones The temperature of ocean water decreases as depth increases.

11. Chapter 13 Section1 Earth’s Oceans Characteristics of Ocean Water, continued • Surface Temperature Changes Surface-zone temperatures vary with latitude and the time of year. • Surface temperatures range from 1ºC near the poles to about 24 ºC near the equator. • The surface zone is heated more in the summer.

12. Chapter 13 Section1 Earth’s Oceans The Ocean and the Water Cycle • The water cycle is the continuous movement of water from the ocean to the atmosphere to the land and back to the ocean. • The ocean is an important part of the water cycle because nearly all of Earth’s water is in the ocean.

13. Chapter 13 Section1 Earth’s Oceans

14. Chapter 13 Section1 Earth’s Oceans A Global Thermostat • The ocean regulates atmospheric temperatures. • A Thermal Exchange The ocean absorbs and releases thermal energy much more slowly than dry land does. • The circulation of warm water causes some coastal lands to have warmer climates than they would have with the currents.

15. Chapter 13 Section2 The Ocean Floor Objectives • Describe technologies for studying the ocean floor. • Identify the two major regions of the ocean floor. • Classify subdivisions and features of the two major regions of the ocean floor.

16. Chapter 13 Section2 The Ocean Floor Studying the Ocean Floor • Seeing by Sonar Scientists use sonar to determine the ocean’s depth. • Oceanography via Satellite Scientists use images from the satellite Seasat to study ocean currents. • Studying the Ocean with Geosat Scientists use the Geosat satellite to measure slight changes in the height of the ocean’s surface.

17. Chapter 13 Section2 The Ocean Floor

18. Section2 The Ocean Floor Chapter 13 Revealing the Ocean Floor • Regions of the Ocean Floor The two regions of the ocean floor are the continental margin and the deep-ocean basin. • Underwater Real Estate The continental margin and the deep-ocean basin are subdivided into different areas and have different features, as shown on the next two slides.

19. Section2 The Ocean Floor Chapter 13

20. Section2 The Ocean Floor Chapter 13

21. Section2 The Ocean Floor Chapter 13 Exploring the Ocean with Underwater Vessels • Piloted Vessels: Alvin and Deep FlightAlvin and Deep Flight are two research vessels that can reach some of the deepest parts of the ocean. • Robotic Vessels: JASON II and MedeaJASON II and Medea are a robotic team. JASON II explores the ocean floor. Medea is attached to JASON II with a tether and explores above the the sea floor.

22. Section3 Life in the Ocean Chapter 13 Objectives • Identify the three groups of marine life. • Describe the two main ocean environments. • Identify the ecological zones of the benthic and pelagic environments.

23. Chapter 13 Section3 Life in the Ocean Three Groups of Marine Life • Organisms that float or drift freely near the ocean’s surface are calledplankton. • Organisms that swim actively in the open ocean are callednekton. • Organisms that live on or in the ocean floor are calledbenthos.

24. Chapter 13 Section3 Life in the Ocean

25. Chapter 13 Section3 Life in the Ocean The Benthic Environment • TheBenthic Environment is the region near the bottom of a pond, lake, or ocean. • The benthic environment is divided into ecological zones based on where different types of benthos live.

26. Chapter 13 Section3 Life in the Ocean The Benthic Environment, continued • The Intertidal Zone is where the ocean meets the land. • The intertidal zone is exposed to air for part of the day. Organisms found in this zone include starfish, sea anemones, barnacles, crabs, and seaweed.

27. Chapter 13 Section3 Life in the Ocean The Benthic Environment, continued • The Sublittoral Zone The sublittoral zonebegins at the low-tide limit and extends to the continental shelf, which is about 200 m below sea level. • The temperature, water pressure, and amount of sunlight remain fairly constant in this zone. Coral is found in this zone.

28. Chapter 13 Section3 Life in the Ocean The Benthic Environment, continued • The Bathyal Zone The bathyal zoneextends from the continental shelf to the abyssal zone. The depth of this zone ranges from 200 m to 4,000 m below sea level. • Because of the lack of sunlight, few plants are found in this zone. Animals such as sea stars, sponges, and octopuses are found here.

29. Chapter 13 Section3 Life in the Ocean The Benthic Environment, continued • The Abyssal Zone The abyssal zoneis the largest ecological zone of the ocean and can reach 4,000 m in depth. • No plants live in this zone. The few animals that can be found include crabs, sponges, sea cucumbers, and worms.

30. Chapter 13 Section3 Life in the Ocean The Benthic Environment, continued • The Hadal Zone The hadal zone consists of the floor of the ocean trenches and any organisms found there. The depth can reach from 6,000 m to 7,000 m below sea level. • The only organisms that have been found in this zone include a type of sponge, a few species of worms, and a type of clam.

31. Chapter 13 Section3 Life in the Ocean The Pelagic Environment • The zone near the ocean’s surface and at the middle depths is called thepelagic environment. • The pelagic environment is above the abyssal zone and beyond the littoral zone. • The two major zones of the pelagic environment are the neritic zone and the oceanic zone.

32. Chapter 13 Section3 Life in the Ocean The Pelagic Environment, continued • The Neritic Zone The neritic zone is a warm, shallow zone that covers the continental shelf. • The neritic zone contains the largest concentration of marine life. • The neritic zone receives more sunlight than other ocean zones, allowing plankton to grow and serve as a food supply.

33. Chapter 13 Section3 Life in the Ocean The Pelagic Environment, continued • The Oceanic Zone The oceanic zone includes the volume of water that covers the entire sea floor except for the continental shelf. • The deeper parts of the oceanic zone have colder water temperatures and much greater pressure than the neritic zone. • Organisms are more spread out in the oceanic zone.

34. Chapter 13 Section4 Resources from the Ocean Objectives • List two ways of harvesting the ocean’s living resources. • Identify three nonliving resources in the ocean. • Describe the ocean’s energy resources.

35. Chapter 13 Section4 Resources from the Ocean Living Resources • Fishing the Ocean Fish are the larges group of organisms take from the ocean. • Farming the Ocean People have begun to raise ocean fish and other organisms in fish farms to help meet the demand for seafood. • Savory Seaweed Many types of seaweed are harvested from the ocean for use as food.

36. Chapter 13 Section4 Resources from the Ocean Nonliving Resources • Oil and Natural Gas Oil and natural gas are used for energy and are found under layers of impermeable rock. • Searching for Oil Scientists use seismic equipment to find oil and natural gas under the ocean floor.

37. Chapter 13 Section4 Resources from the Ocean Nonliving Resources, continued • Fresh Water and Desalination Fresh water can be collected for human use by removing the salt from ocean water. • Sea-Floor Minerals Scientists estimate that 15% of the ocean floor is covered with mineral-rich nodules. However, mining them is costly and difficult. • Tidal Energy is energy generated from the movement of the tides.

38. Chapter 13 Section4 Resources from the Ocean Nonliving Resources, continued • Wave Energy The constant motion of waves is a clean, renewable energy resource. • Researchers have found certain areas of the world where wave energy can generate enough electrical energy to make building power plants worthwhile.

39. Chapter 13 Section 5Ocean Pollution Objectives • Explain the difference between point-source and nonpoint-source pollution • Identify three different types of point-source pollution. • Describe what is being done to control ocean pollution.

40. Chapter 13 Section5 Ocean Pollution Nonpoint-Source Pollution • Pollution that comes from many sources rather than from a single site is callednonpoint-source pollution. • Most ocean pollution is nonpoint-source pollution and can be difficult to regulate and control.

41. Chapter 13 Section5 Ocean Pollution Point-Source Pollution • Trash Dumping Dumping trash in the deeper parts of the ocean is a common practice in many countries. • Effects of Trash Dumping Trash thrown in the ocean can be harmful to ocean organisms. • Sludge Dumping Sludge is the solid waste removed from raw sewage. Sludge can pollute beaches and kill marine life.

42. Chapter 13 Section5 Ocean Pollution Point-Source Pollution, continued • Oil Spills If not handled properly, oil transports can cause oil spills.

43. Chapter 13 Section5 Ocean Pollution Point-Source Pollution, continued • Effects of Oil Spills Oil spills can harm or kill many plants and animals. • Preventing Oil Spills New technology is being used to safeguard against oil spills. Oil tankers are now being built with two hulls instead of one.

44. Chapter 13 Section5 Ocean Pollution Saving Our Ocean Resources • Nations Take Notice Many international agreements and laws restrict ocean pollution. • Citizens Taking Charge People have demanded that their governments work to solve ocean pollution and have begun organizing beach cleanups. • Action in the United States The U.S. has passed laws to control local pollution.

45. Chapter 13 Exploring the Oceans Concept Mapping Use the terms below to complete the concept map on the next slide.

46. Chapter 13 Exploring the Oceans

47. Exploring the Oceans Chapter 13