The Ocean Floor

14.1 The Vast World Ocean

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”?

The Blue Planet

Fig 1 Pg 394

• 70% of Earth’s surface covered by ocean.

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.

The Vast World Ocean

• Bathymetry is the measurement of ocean depths and charting topography of ocean floor

36,000 ft deep

Marianas trench

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

The Challenger

Recorded depth of the ocean floor

The Topography of the Ocean

You could see mountains on bottom of ocean if Earth’s oceans were drained

The Topography of the Ocean

A Continental slopeB SeamountC Continental RiseD Mid Ocean RidgeE Abyssal PlainF Continental ShelfG Ocean Trench

E

Measuring Topography on the Ocean Floor

Three types of technology allow scientists to study the ocean floor1. sonar2. satellites3. submersibles

• 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

Measuring Topography on the Ocean Floor

Sonar Methods

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

Measuring Topography on the Ocean Floor

Satellite Methods

• 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

Measuring Topography on the Ocean Floor

Submersibles

First submersible was used in 1934 by William Beebe

SubmersiblesSubmersibles can:

Record video and photos of previously unknown creatures that live in the abyss

Collect water samples and sediment samples for analysis