Chapter 14
The Ocean Floor
Section 14.1
The Vast World
Ocean
The Vast World Ocean
• The “Blue Planet” or “Water Planet”
– Nearly 71% of Earth’s surface is covered by the
global ocean.
– Oceanography – is a science that draws on the
methods and knowledge of geology, chemistry,
physics and biology to study all aspects of the
world ocean.
The Vast World Ocean
The Vast World Ocean
• Geography of the Oceans
– Of the 510 million square km of Earth’s surface
360 million square km is covered in water
– The world ocean can be divided into four main
ocean basins:
1. Pacific Ocean – largest and has the greatest depth
2. Atlantic Ocean – half the size of the Pacific and not
quite as deep
3. Indian Ocean – slightly smaller than the Atlantic and
is mainly in the southern hemisphere
4. Artic Ocean – 7% of the size of the Pacific
What percentage of Earth’s surface is
covered by water?
A.
B.
C.
D.
45 percent
51 percent
71 percent
85 percent
Oceanography is the
A. science that draws on the methods and
knowledge of geology, chemistry, physics and
biology to study all aspects of the world
ocean.
B. study of all the living organisms in the oceans.
C. study of ocean water chemistry.
D. study of the ocean floor and its topography.
Which of the world’s oceans is the
largest and deepest?
A.
B.
C.
D.
Arctic Ocean
Atlantic Ocean
Indian Ocean
Pacific Ocean
The Vast World Ocean
• Mapping the Ocean Floor
– The topography of the ocean floor is as diverse as
that of the continents.
– Bathymetry – is the measurement of ocean
depths and the charting of the shape or
topography of the ocean floor. (bathos = depth,
metry = measurement)
– Challenger expedition – Dec. 1872-May 1876
• First understanding of the ocean floors topography
• 127,500 km trip (every ocean except Artic)
The Vast World Ocean
• 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.
The Vast World Ocean
The Vast World Ocean
• Sonar – an acronym for sound navigation and
ranging. It is also referred to as echo
sounding.
– Developed in the 1920’s.
– Sonar works by transmitting sound waves toward
the ocean bottom and timing how long it takes for
the echo to come back.
– Used to map the ocean floor
– “Mowing the lawn” – method of sonar where a
multibeam sonar is used in a back and forth
motion to map the ocean floor
The Vast World Ocean
The Vast World Ocean
• Satellites
– Satellites are able to measure small differences by
bouncing microwaves off the ocean surface.
– Using this new technology, scientists have
discovered that the ocean surface is not perfectly
flat.
– Differences in the height of the ocean surface are
caused by ocean-floor features.
The Vast World Ocean
Bathymetry is
A. the measurement of ocean currents,
tides and waves.
B. the measurement of ocean depths and
the charting of the shape or topography
of the ocean floor.
C. the study of the various sediments on
the ocean floor.
D. the study of seismic activity on the
ocean floor.
What does sonar equipment measure?
A. The density of the ocean’s water
B. The depth of the ocean floor
C. The sound produced by bottomdwelling ocean creatures
D. The shape of the ocean surface
Scientists use satellites to measure the
A.
B.
C.
D.
Ocean floor depth.
Size of underwater features.
Sea-surface height.
Ocean’s salinity.
The Vast World Ocean
• Submersibles – small underwater crafts used for
deep-sea research.
– First submersible used in 1934 by William Beebe
• Dove 923 meters deep off of Bermuda
• Steel sphere that was tethered to the ship
– 1960 – Jacques Piccard descended 10,912 meters into
the Mariana Trench
• Untethered submersible named Trieste
– Manned submersibles
• Alvin – can reach 4000 meters
• Sea Cliff II – can reach 6000 meters
– Today, many submersibles are unmanned and
operated remotely by computers. These remotely
operated vehicles (ROVs) can remain underwater for
long periods.
Submersibles
Which of the following is NOT an
example of a submersible?
A.
B.
C.
D.
Alvin
Trieste
Sea Cliff II
Red October