1. Warm Up 2/5/08 Name Earth’s four main ocean basins. Name Earth’s four main ocean basins. Pacific, Atlantic, Indian, and Arctic Pacific, Atlantic, Indian, and Arctic Approximately how much of Earth’s surface is covered by ocean? (60%, 71%, 66%, or 78%) Approximately how much of Earth’s surface is covered by ocean? (60%, 71%, 66%, or 78%) 71% 71% What oceanic feature does an oceanic- continental subduction zone produce? What oceanic feature does an oceanic- continental subduction zone produce? Oceanic trench Oceanic trench

2. The Vast World Ocean Chapter 14, Section 1

3. The Blue Planet Nearly 71% of Earth’s surface is covered by the global ocean Nearly 71% of Earth’s surface is covered by the global ocean It has only been since the late 1800s that the ocean became an important focus of scientific studies It has only been since the late 1800s that the ocean became an important focus of scientific studies Oceanography – a science that draws on the methods of geology, chemistry, physics and biology to study all aspects of the world ocean Oceanography – a science that draws on the methods of geology, chemistry, physics and biology to study all aspects of the world ocean

4. The Blue Planet

5. Geography of the Oceans The world ocean can be divided into four main ocean basins – the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic Ocean The world ocean can be divided into four main ocean basins – the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, and the Arctic Ocean The Pacific Ocean is the largest ocean and the largest geographic feature on Earth (deepest at an average depth ~ 3940 m) The Pacific Ocean is the largest ocean and the largest geographic feature on Earth (deepest at an average depth ~ 3940 m) The Atlantic Ocean is about half the size of the Pacific, and much more narrow The Atlantic Ocean is about half the size of the Pacific, and much more narrow The Indian Ocean is slightly smaller than the Atlantic, but has about the same average depth The Indian Ocean is slightly smaller than the Atlantic, but has about the same average depth The Arctic Ocean is only about 7% the size of the Pacific and about ¼ as deep as the rest of the oceans The Arctic Ocean is only about 7% the size of the Pacific and about ¼ as deep as the rest of the oceans

6. Geography of the Oceans

7. What are the four main oceans? What are the four main oceans?

8. Mapping the Ocean Floor If all the water were drained from the oceans, we would see everything from chains of volcanoes, tall mountain ranges, trenches, and large submarine plateaus If all the water were drained from the oceans, we would see everything from chains of volcanoes, tall mountain ranges, trenches, and large submarine plateaus The topography of the ocean floor is as diverse as that of continents The topography of the ocean floor is as diverse as that of continents Bathymetry – the measurement of ocean depths and the charting of the shape or topography of the ocean floor Bathymetry – the measurement of ocean depths and the charting of the shape or topography of the ocean floor Today’s technology – particularly sonar, satellites, and submersibles – allows scientists to study the ocean floor in a more efficient and precise manner than ever before Today’s technology – particularly sonar, satellites, and submersibles – allows scientists to study the ocean floor in a more efficient and precise manner than ever before

9. Mapping the Seafloor

10. Sonar Sonar is an acronym for sound navigation and ranging Sonar is an acronym for sound navigation and ranging It works by transmitting sound waves toward the ocean bottom It works by transmitting sound waves toward the ocean bottom A sensitive receiver intercepts the echo reflected from the bottom A sensitive receiver intercepts the echo reflected from the bottom Then a clock precisely measures the time interval to fractions of a second Then a clock precisely measures the time interval to fractions of a second Depth can be calculated from the speed of sound in water and the time required for the energy pulse to reach the ocean floor and return Depth can be calculated from the speed of sound in water and the time required for the energy pulse to reach the ocean floor and return

11. Sonar

12. Satellites We can now measure the shape of the ocean floor from space with satellites orbiting Earth We can now measure the shape of the ocean floor from space with satellites orbiting Earth Gravity attracts water towards regions where massive ocean floor features occur Gravity attracts water towards regions where massive ocean floor features occur This produces relative elevated areas on the ocean surface by mountains and ridges and depressions at canyons and trenches This produces relative elevated areas on the ocean surface by mountains and ridges and depressions at canyons and trenches Devices on satellites can measure variations in sea-surface height as small as 3-6 cm Devices on satellites can measure variations in sea-surface height as small as 3-6 cm Using this data and sonar data, scientists are creating detailed maps of the ocean floor Using this data and sonar data, scientists are creating detailed maps of the ocean floor

13. Satellites

14. What do sonar and satellites tell us about the ocean floor? What do sonar and satellites tell us about the ocean floor?

15. Submersibles Submersible – a small underwater craft used for deep-sea research Submersible – a small underwater craft used for deep-sea research They are used to collect data about areas of the ocean that were previously unreachable by humans They are used to collect data about areas of the ocean that were previously unreachable by humans Most submersibles are unmanned and operated by computers Most submersibles are unmanned and operated by computers

16. Submersibles

17. Assignment Do Section 14.1 Assessment #1-7 (pg.400) Do Section 14.1 Assessment #1-7 (pg.400)