Oceanography
• Does water pressure increase of decrease with
depth?
• Why is the surface temperature of oceans
more variable than the water near the ocean
floor?
• Why will a boat float higher in the Atlantic
Ocean than it will in the Potomac River?
• What is the average concentration of
dissolved salts in 1000 grams of ocean water?
Salinity (salt)
• 35% is the average concentration of
dissolved salts in 1000 grams of
ocean water.
• When sea water freezes, most the
salt is left behind, increasing the
density of the remaining seawater.
• Salinity tends to be above average in
hot areas
• Which pair of factors would both
cause salinity to increase?
– Melting of sea ice and precipitation
– Evaporation and freezing of sea
water
Label the Oceans
•Atlantic
Ocean
•Pacific
Ocean
•Indian
Ocean
•Arctic
Ocean
Facts
• Phytoplankton is the base of the marine
food chain and the primary energy source
of marine ecosystems
• The zone in which the ocean temperatures
change rapidly is called the?
– Mixed layer
– Seasonal layer
– Thermocline
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Which of the following statements
about ocean pressure is true?
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A. Pressure increases with
temperature
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B. Pressure decreases with depth
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C. Pressure increases with depth
D. The pressure is equal throughout
the ocean
Why is the surface temperature of
oceans more variable than the water
near the ocean floor?
E. more energy is exchanged at the
surface
F. more animals live near the surface
G. water is less dense at the surface
H. salt concentration is more variable
at the surface
Which pair of factors would both
cause salinity to increase?
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• A. evaporation and freezing of
sea water
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• B. freezing seawater and
precipitation
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• C. precipitation and melting of
sea ice
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• D. melting of sea ice and
evaporation
The two most common ions found
in ocean water are
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• E. chloride and sodium
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• F. potassium and calcium
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• G. phosphate and nitrate
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• H. magnesium and sodium
When seawater freezes, most of the
salt
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• A.)is included in the ice,
increasing its density
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• B.) is left behind, increasing the
density of the remaining
seawater
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• C.) is included in the ice,
decreasing its density
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• D.) is left behind, decreasing the
density of the remaining
seawater
Salinity tends to be above average
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• e. in areas of high precipitation
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• f. where large rivers enter the ocean
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• g. where icebergs are melting
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• h. in hot areas
The base of the marine food chain and the
primary energy source for marine
ecosystems is
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• i. zooplankton
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• j. phytoplankton
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• k. bacteria
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• l. salt
Questions/Answers
• A boat will float higher in the Atlantic Ocean than it will
in the Potomac River because ocean water has ?
– A lower freezing point
– A greater density
• Why is the surface temperature of oceans more
variable than the water near the ocean floor?
– More energy is exchanged at the surface
– More animals live near the surface
• Which of the following statements about oceans is
true?
– Pressure increases with temperature
– Pressure increases with depth
The Water
• The two most common ions found in the ocean
water are chloride and sodium
• Melting of polar ice caps will result in long-term
changes in sea levels.
• Upwelling is important to ocean life because it
brings nutrients to the surface water
• Major commercial fishing
areas are located in areas of
Persistent upwelling
Four Oceans
Arctic
Ocean
Pacific
Ocean
Atlantic
Ocean
Indian Ocean
UPWELLING
• Upwelling is important to
ocean life because it
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• A. cools the surface water
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• B. brings nutrients to the
surface water
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• C. keeps ocean temperature
uniform
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• D. brings carbon dioxide to the
surface
• Major commercial fishing
areas are usually located in
areas
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• e. where density currents form
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• f. where seawater oxygen
levels are high
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• g. of persistent upwelling
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• h. that experience frequent
turbidity currents
Ocean Floor Questions
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What is the steepest region of a continental margin?
What is the flattest surface of Earth?
The continental slope is located at the end of the?
What is a cone-shaped undersea mountains of volcanic
origin that rises high above the ocean floor called?
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The steepest region of a continental margin
is the
A. continental slope
B. continental ridge
C. continental rise
D. continental shelf
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The flattest surface of Earth is a(n)
e. island arc
f. guyout
g. seamount
h. abyssal plain
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The continental slope is located at the end
of the _____.
e. continental shelf
f. ocean trench
g. shoreline
h. rift zone
All of the following ocean floor features
indicate tectonic activity except
v. deep-sea trench
w. mid-ocean ridge
x. seamount
y. abyssal plain
Mid-Ocean Ridge
• Seafloor rocks near the mid-ocean ridge are older or
younger then the rocks far from the mid-ocean ridge???
• Mid ocean ridges are undersea mountain ranges where
lithospheric plates are moving apart and new oceanic crust
is being formed.
Rip Current
How should a person escape from a rip current?
They should swim parallel to shore to escape the narrow
current and let the waves carry you.
Convergent Boundaries
• Deep-sea trenches occur at convergent plate
boundaries where one tectonic plate is sinking
beneath another
• Suppose sound travels at an average rate of 1500
meters per second through seawater above a
particular locationHow deep is the ocean if a
sound pulse takes 10 seconds to reach the
bottom and return to a surface ship?
• 150 meters
• 300 meters
• 7500 meters
• 15000 meters
The Marianas Trench in the Pacific
Ocean is 36,160 feet below sea level.
This deep oceanic trench is caused by:
• A.) swift ocean currents eroding
away the ocean floor
• B.) the collapse of an empty
magma chamber in a large
volcano
• C.) excessive boat traffic
disrupting the normal
sedimentation process
• D.) two tectonic plates colliding
and one plunging below the
other
Barrier islands form off the coast of the land.
Where are most barrier beaches found in the
U.S.?
Currents
• What causes a longshore current to form?
• Turbidity currents move along the…?
• Surface currents in the ocean are primarily
cause by?
Current Facts
• Surface currents flowing away from the
equator carry warm water.
• The Gulf Stream current affects the weather
in Virginia.
• The effect of the Earth’s rotation on winds and
ocean currents is called the Coriolis Effect.
• Deep ocean current are driven by differences
in density.
• Turbidity currents move
along the bottom
• Surface currents in the
ocean are primarily caused
by winds.
• What causes a longshore
current to form?
– Waves striking the beach at
an angle rather than straight
More about currents
• Deep ocean currents are driven by:
A.) tidal forces
B.) differences in density
C.) differences in oxygen content
D.) changes in conveyor belt circulation
• Which of the following is not a cause of ocean
currents?
A.) wind
B.) gravity
C.) variation in water density
D.) type of seal life
Surface Currents
• Surface currents flowing away from the
equator carry _____ water. In the northern
hemisphere, surface currents tend to flow
________. Surface currents in the ocean are
most commonly driven by ________.
-clockwise, warm, wind
Sun, Moon, and Earth
• Tides are highest when
Earth is in line with both
the sun and moon.
• When the Earth, sun,
and moon are at 90
degree angles to each
other, the tidal range is
______
• When the Earth, moon,
and sun are lined up,
what type of tide
occurs?
Tide Facts and Terms
• What is most
responsible for tides?
• What is the difference
between the high and
low tide water levels
called?
Waves
• The lowest point of a wave is called the trough.
• As a wave moves in shore and grows in height it
will eventually topple over, forming a breaker.
• What causes the top of a wave to fall forward
when it moves in shore? Friction with the
bottom
• The distance from crest to crest or trough to
trough in a wave is the wavelength. Tsunami is a
wave that would have a very long wavelength.
Waves
• Which of the following waves can have a very
long wavelength?
A.) rip current
B.) tsunami
C.) surface current
D.) upwelling current
You Answer
• The lowest point of a wave is called the
a.) crest
b.) height
c.) trough
d.) tide
As a wave moves in shore and grows in height it will
eventually topple over, forming a
a.) mess
b.) tide
c.) breaker
d.) current
• What causes the top of a wave to fall forward
when it moves to shore?
a.) friction with the bottom
b.) storm surges
c.) upwelling currents
d.) wind