Dr. Alida Bundy Fisheries and Oceans Canada Bedford Institute of Oceanography
Oceanography Does water pressure increase of decrease with depth? Why is the surface temperature of...
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Transcript of Oceanography Does water pressure increase of decrease with depth? Why is the surface temperature of...
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
• Which of the following statements about ocean pressure is true?
• • A. Pressure increases with
temperature• • B. Pressure decreases with depth• • 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?
• • A. evaporation and freezing of sea
water• • B. freezing seawater and
precipitation• • C. precipitation and melting of sea
ice• • D. melting of sea ice and evaporation
The two most common ions found in ocean water are
• • E. chloride and sodium• • F. potassium and calcium• • G. phosphate and nitrate• • H. magnesium and sodium
When seawater freezes, most of the salt
• • A.)is included in the ice,
increasing its density• • B.) is left behind, increasing the
density of the remaining seawater
• • C.) is included in the ice,
decreasing its density• • D.) is left behind, decreasing
the density of the remaining seawater
Salinity tends to be above average• • e. in areas of high precipitation• • f. where large rivers enter the ocean• • g. where icebergs are melting• • h. in hot areas
The base of the marine food chain and the primary energy source for marine ecosystems is
• • i. zooplankton• • j. phytoplankton• • k. bacteria• • 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
Atlantic Ocean
Indian Ocean
Pacific Ocean
Arctic Ocean
UPWELLING• Upwelling is important to
ocean life because it• • A. cools the surface water• • B. brings nutrients to the
surface water• • C. keeps ocean temperature
uniform• • D. brings carbon dioxide to the
surface
• Major commercial fishing areas are usually located in areas
• • e. where density currents form• • f. where seawater oxygen levels
are high• • g. of persistent upwelling• • h. that experience frequent
turbidity currents
Ocean Floor Questions
• 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?
• The steepest region of a continental margin is the
• • A. continental slope• • B. continental ridge• • C. continental rise• • D. continental shelf• •
• The flattest surface of Earth is a(n)• • e. island arc• • f. guyout• • g. seamount• • h. abyssal plain
• 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 CurrentHow 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 forcesB.) differences in densityC.) differences in oxygen contentD.) changes in conveyor belt circulation• Which of the following is not a cause of ocean currents?A.) windB.) gravityC.) variation in water densityD.) 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 currentB.) tsunami C.) surface currentD.) upwelling current
You Answer
• The lowest point of a wave is called thea.) crestb.) heightc.) troughd.) tideAs a wave moves in shore and grows in height it will eventually
topple over, forming a a.) messb.) tidec.) breakerd.) current
• What causes the top of a wave to fall forward when it moves to shore?
a.) friction with the bottomb.) storm surgesc.) upwelling currentsd.) wind