The Ocean Floor

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The Ocean Floor

• 14.1 The Vast World Ocean

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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?

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The Blue Planet

• 70 of Earths surface covered by ocean.

Fig 1 Pg 394
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The Blue Planet

• The world can be divided into four main ocean
  basinsthe Pacific Ocean, the Atlantic Ocean, the
  Indian Ocean, and the Arctic Ocean.

• The Pacific Ocean is the largest and has the
  greatest depth.

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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 Earths 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

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The Challenger
Recorded depth of the ocean floor
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The Topography of the Ocean
You could see mountains on bottom of ocean if
Earths oceans were drained
9
The Topography of the Ocean
E
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

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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

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Sonar Methods
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
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

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Submersibles
First submersible was used in 1934 by William
Beebe
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Submersibles
Submersibles can Record video and photos of
previously unknown creatures that live in the
abyss Collect water samples and sediment
samples for analysis