1. The Ocean Floor
14.1 The Vast World Ocean

2. The Ocean Floor What does the bottom of the ocean look like?
If the water of the ocean were drained, what would you see?
How much of the Earth is covered with water?
Why is Earth called the “Blue Planet”?

3. The Blue Planet 70% of Earth’s surface covered by ocean. Fig 1 Pg 394
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Fig 1 Pg 394

4. The Blue Planet
The world 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 and has the greatest depth.

5. The Vast World Ocean
Bathymetry is the measurement of ocean depths and charting topography of ocean floor
36,000 ft deep
Marianas trench

6. The Challenger
In 1872 HMS Challenger expedition made the first study of Earth’s oceans
65,000 mile trip took the ship and its crew of scientists to every ocean except the Arctic
How did they measure the depths of the oceans?
used line and sinker

7. The Challenger
Recorded depth of the ocean floor

8. The Topography of the Ocean
You could see mountains on bottom
of ocean if Earth’s oceans were drained
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9. The Topography of the Ocean
A Continental slope
B Seamount
C Continental Rise
D Mid Ocean Ridge
E Abyssal Plain
F Continental Shelf
G Ocean Trench

10. Measuring Topography on the Ocean Floor
Three types of technology allow scientists to study the ocean floor
1. sonar
2. satellites
3. submersibles

11. Measuring Topography on the Ocean Floor
Sonar
Invented in the 1906 by Lewis Nixon
Sonar is an acronym for Sound Ocean Navigation and Ranging
Also referred to as echo sounding
Sonar works by transmitting sound waves toward the ocean bottom

12. Sonar Methods
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13. Measuring Topography on the Ocean Floor
Satellites
Satellites are able to measure small differences by bouncing microwaves off the ocean surface
Can measure variations in sea-surface height as small as 3 to 6 centimeters (1 to 2 inches)
Differences in the height of the ocean surface are caused by ocean-floor features

14. Satellite Methods
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15. Measuring Topography on the Ocean Floor
Submersibles
Submersibles are small underwater crafts used for deep-sea research
Today, many submersibles are unmanned and operated remotely by computers. These remotely operated vehicles (ROVs) can remain underwater for long periods

16. Submersibles
First submersible was used in 1934 by William Beebe

17. Submersibles Submersibles can:
Record video and photos of previously unknown creatures that live in the abyss
Collect water samples and sediment samples for analysis