Chapter 14 – The Ocean Floor
14.1 The Vast World Ocean
Text pp 394-400
The Blue Planet
• Nearly 71% of Earth’s
surface is covered by the
global ocean.
Oceanography is the science that studies the global
ocean, and draws on geology, chemistry, physics
and biology.
Geography of the Oceans
• About 360 million square kilometers, or 71%,
of all the surface of Earth is represented by
oceans and smaller seas, such as the
Caribbean Sea.
• The world ocean can be divided into four
main ocean basins – the Pacific Ocean…
•Largest ocean, and the largest single geographic
feature on Earth.
•Covers half the ocean surface.
•World’s deepest ocean.
• …the Atlantic Ocean…
•Half the size of the Pacific Ocean.
•Not quite as deep as the Pacific.
•Relatively narrow in width.
• … the Indian Ocean…
•Slightly smaller than the Atlantic.
•Just as deep as the Atlantic.
•Located almost entirely in the Southern Hemisphere.
• … and the Arctic Ocean.
•About 7% the size of the Pacific Ocean
•A little more than ¼ deep as the rest of the oceans.
Mapping the Ocean Floor
• The topography of the
ocean floor is as
diverse as that of the
continents.
• We would see
volcanoes, tall
mountain ranges and
large submarine
plateaus if we could
see to the bottom.
• Bathymetry (bathos = depth, metry = measurement) is
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.
SONAR
• SONAR stands for…
• SOund
• NAvigation and
• Ranging
SONAR works by transmitting sound waves
toward the ocean bottom, and a receiver
intercepts the echo reflected upwards.
• Depth can be calculated from the speed of
sound waves in water, and the time required
from the energy pulse to reach the ocean
floor and return. In this way a profile of the
ocean floor is created.
Satellites
• Measuring the shape of the ocean floor from
space is another recent technological
breakthrough. Satellites can give us
extremely accurate measurements, using
microwaves instead of sound waves.
Submersibles
• A submersible is a
small underwater
craft used for deepsea research.
Submersibles are used
to collect data about
areas of the ocean
that were previously
unreachable by
humans.
• Today, many
submersibles are
unmanned and
operated remotely
by computers.
These remotely
operated vehicles
(ROVs) can remain
under water for long
periods.