Download Exam 3 PRACTICE – Winter 2016 KEY

EXAM 3
PSCI 131
WINTER 2016
PRACTICE (KEY)
Ocean Water and Life
1. List the three most abundant components in seawater:
a. WATER
b. SODIUM
c. CHLORINE
2. Which of the following increase the salinity of seawater? Circle all that apply.
a. Evaporation
b. Precipitation
c. Runoff
d. Sea ice melting
e. Sea ice formation
3. What two factors control the density of ocean water?
a. TEMPERATURE
b. SALINITY
4. The two sources of dissolved material (salt) in ocean water are (mark one answer)
a. Space dust and meteors
b. Continental sediment and volcanoes
c. Biologic activity
d. Sodium and chlorine
5. In what climate belt does the ocean tend to have the highest average surface salinity?
a. Polar
b. Tropical
c. Subpolar
d. Temperate
e. Subtropical
6. Why is salinity highest at the latitude from the previous question?
a. High evaporation rate
b. Formation of sea ice
c. Little precipitation
d. Melting of sea ice
e. (a) and (c)
f. None of the above
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7. A thermocline is
a. A rapid change in water temperature with depth
b. A rapid change in water salinity with depth
c. A barrier to vertical water movement
d. Not a barrier to vertical water movement
e. All of the above
f. None of the above
g. (a) and (c)
h. (b) and (d)
8. Tropical oceans have a thermocline…
a. …all year long
b. …during the summer only
c. …during the winter only
d. …during no part of the year (they never have a thermocline)
9. The two factors that control the biologic productivity of a given area of the ocean are (2 pts)
a. SUNLIGHT
b. NUTRIENTS
Refer to the graph of temperate-latitude biologic productivity for the next TWO questions.
10. The fact that nutrient levels in the surface waters are high in early spring is one reason why
productivity (phytoplankton abundance) increases sharply during this time. The other reason is
a. Sunlight availability increases
b. A thermocline develops
c. Deep-ocean circulation becomes more active
d. Surface current activity increases
e. All of the above
11. Why does productivity in the temperate latitude ocean remain high all summer long?
a. Sunlight availability increases throughout the summer months
b. A strong thermocline develops
c. No thermocline develops
d. Nutrient levels remain high
e. None of the above; productivity drops in the summer
12. What is the foundation of the marine food chain in most ocean regions?
a. Benthic organisms
b. Photosynthesizing plankton
c. Chemosynthesizing plankton
d. Nektonic organisms
13. Which region of the world ocean never has a thermocline?
a. Subtropical ocean
b. Tropical ocean
c. Polar ocean
d. Temperate ocean
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The Dynamic Ocean
14. Thermohaline circulation is another term for
a. Upwelling
b. Surface circulation
c. Wave motion
d. Deep-ocean circulation
e. None of the above
15. A loop of connected surface currents is called a
a. Gyre
b. Coriolis structure
c. Thermocline
d. Pycnocline
16. What is the direct cause of the ocean’s surface currents?
a. Salinity variations
b. Density variations
c. Vertical circulation
d. Wind
17. In terms of heat energy, what do surface currents do?
a. They move heat from colder to warmer areas
b. They bring heat from polar latitudes towards the equator
c. They bring heat from the equatorial regions toward the poles
d. They do not affect the distribution of surface heat at all
18. Deep-ocean circulation is driven by the sinking of surface water in the polar oceans. Why does
this happen?
a. In winter these waters are saltier and colder, and therefore denser, than deeper water
b. All year long these waters are less dense than deeper waters
c. In summer these waters are saltier and warmer, and therefore less dense, than deeper water
d. The question is false; deep-ocean circulation is driven by density changes in the tropical
ocean
19. Why do the British Isles have a warmer climate than central Canada, even though both regions are
at the same latitude?
a. Because the North Atlantic gyre occasionally reverses its rotation direction, causing warm
water to move toward the British Isles
b. Because the Gulf Stream brings warm tropical water to the British Isles, and not to
Canada
c. Because there are frequent upwellings of warm water from the deep ocean just off the
coast of Britain
d. Because the jet stream brings warm tropical air up to the British Isles from the Gulf of
Mexico
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20. Match the parts of a wave to the correct letters on the diagram below: (5 pts)
a. Trough
D
b. Amplitude (wave height)
B
c. Crest
A
d. Wave base
E
e. Wavelength
C
21. If a wave’s wavelength is 5 meters, what is its wave base?
a. 10 meters
b. 5 meters
c. 15 meters
d. 2.5 meters
22. When a wave is approaching a shoreline and the sea bottom becomes shallower than the wave’s
wave base, what happens?
a. The wave energy dissipates and the wave disappears
b. The entire wave slows down
c. The bottom of the wave slows down
d. The wave breaks
e. All of the above
f. (c) and (d)
g. (a) and (b)
23. You are stranded on an island and have built a small raft. You notice that, far offshore, there are
deep-water waves that are bypassing the island and moving in the direction of the mainland. You
reason that, if you paddle your raft to those waves, they will carry you to the mainland. Will this
work?
a. Yes
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b. No
c. Not enough information to answer the question
24. Match each shoreline feature to the correct picture. Write the letter of the correct names in the
white boxes. Pictures continue on the next page. (7 pts)
a. Tombolo
b. Barrier island
c. Wave-cut platform
d. Sea stack
e. Marine terrace
f. Spit
g. Sea arch
Above picture: left-hand box is E, right-hand box is C
Above picture: B
Above picture: G
Above picture: F
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Above picture: D
Above picture: A
(pictures above are for Question 25.)
25. Beach drift is a zig-zag motion of beach sand that results in net transport of the sand down the
coastline. What causes beach drift?
a. Waves striking the beach at an angle
b. Rip currents
c. Tsunamis
d. Gyres
e. All of the above
f. None of the above
The World Ocean & The Ocean Floor
26. Areas of the ocean floor covered by deep sediment tend to have rugged topography because storm
waves and currents erode the ocean floor, making valleys and canyons.
a. True
b. False
27. Seismic reflection profiling is useful for
a. Calculating the depth of deep-ocean trenches
b. Mapping the ocean floor
c. Detecting the structure of ocean floor bedrock
d. Determining the distance between wave crests
28. Sonar-based bathymetric techniques use sound waves to study the ocean floor’s topography.
a. True
b. False
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29. Match each ocean basin with the correct letter on the map below: (4 pts)
a. Indian
D
b. Pacific
A
c. Arctic
C
d. Atlantic
B
30. Label the parts of the passive margin shown below with the correct terms: (3 pts)
Above diagram: left-hand box is shelf, upper right box is slope, lower right box is rise.
31. Write the appropriate letters in the blanks in the following sentence: Passive margins form when a
continent splits apart and a new ocean basin forms. (2 pts)
a. Is squeezed
b. Sinks into the mantle
c. Splits apart
d. Ocean basin
e. Volcanic island chain
f. Mountain range
g. Subduction zone
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32. What plate tectonic setting do active continental margins develop in?
a. Continental collision zone
b. Divergent boundary
c. Rift zone
d. Subduction zone
e. None of the above
33. Creation of new oceanic crust occurs at
a. Oceanic ridges
b. Deep-ocean trenches
c. Abyssal plains
d. Active margins
e. None of the above
34. On this diagram of an oceanic ridge, which location would have the coldest rock? D
B
A
C
D
35. Which of the following accurately describes oceanic ridges?
a. Are places where old ocean crust is destroyed
b. Elevated because the rock composing them is warm and buoyant
c. Occur as isolated, disconnected segments
d. Have a narrow and steep-sided shape
36. Match each type of ocean sediment with how it forms. (3 pts)
a. Hydrogenous
Made mostly of microscopic shells of organisms
C
b. Terrigenous
Washed or blown into the ocean from continents
B
c. Biogenous
Crystallize directly from seawater
A
37. Choose any one of the three sediment types, and give a specific example of a sediment that
belongs to that category.
Sediment type: hydrogenous, terrigenous, or biogenous
Example:
Hydrogeous: manganese nodules, salt deposits from evaporation
Terrigenous: sand, silt, clay, gravel
Biogenous: dead plankton, calcareous ooze, siliceous ooze, chalk
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