OCEANOGRAPHY EXAM – PRACTICE VERSION-KEY
PSCI 131
Ocean Water and Life
1. The two most abundant components of the dissolved material in the ocean are
a. Magnesium and sulfate
b. Sodium and chlorine
c. Iron and carbon
d. Sodium and carbon
2. Which of the following increase the salinity of seawater?
a. Evaporation and melting of sea ice
b. Precipitation and evaporation
c. Precipitation and melting of sea ice
d. Evaporation and formation of sea ice
3. Which of the following decrease the salinity of seawater?
a. Precipitation and melting of sea ice
b. Evaporation and melting of sea ice
c. Precipitation and evaporation
d. Precipitation and formation of sea ice
4. What two factors directly control the density of ocean water?
a. Temperature and density
b. Depth and salinity
c. Latitude and temperature
d. Temperature and salinity
e. Depth and temperature
5. The two sources of dissolved material (salt) in ocean water are
a. Space dust and meteors
b. Biologic activity
c. Sodium and chlorine
d. Continental sediment and volcanoes
6. Thermoclines do not form barriers to vertical circulation of water.
a. True
b. False
7. Temperate-latitude oceans have a thermocline for part of the year.
a. True
b. False
8. What is a thermocline?
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a.
b.
c.
d.
A rapid acidity change with depth
A rapid salinity change with depth
A rapid temperature change with depth
A rapid warming with increasing depth
The graph below shows variation in the salinity of Atlantic Ocean surface water across a range of
latitudes.
9. At what latitude does the lowest salinity occur?
a. 20 degrees N
b. 40 deg S
c. 60 deg S
d. 0 degrees
e. 40 deg N
10. Why is salinity lowest at this latitude?
a. High evaporation rate
b. Formation of sea ice
c. Heavy precipitation
d. Melting of sea ice
11. Graphs of temperature versus depth and density versus depth for the tropical ocean are mirror
images of each other because
a. Temperature and density are inversely proportional
b. Temperature and density are directly proportional
c. Temperature and density are both controlled by the same processes
d. All of the above
12. In the temperate-latitude ocean, there is a jump in biologic productivity in late March and early
April. Why?
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a.
b.
c.
d.
e.
Water temperature increases
A strong thermocline develops
Nutrients have accumulated in surface water over the winter
Availability of sunlight increases
(c) and (d)
13. Why does productivity in the temperate latitudes drop sharply in late spring, instead of remaining
high all summer long?
a. A strong thermocline develops
b. Water salinity increases
c. The thermocline breaks down
d. Sunlight availability decreases
e. (a) and (d)
14. The basis for the marine food chain in most ocean regions is photosynthesizing plankton.
a. True
b. False
15. In which region of the world ocean does the thermocline exist year-round?
a. Tropical ocean
b. Polar ocean
c. Temperate ocean
d. All of the above
16. Marine biologic productivity (how much life the ocean can support) is very low in the tropical
ocean because
a. There is a strong thermocline year-round
b. Surface water is nutrient-poor
c. Vertical circulation from deep to shallow water is limited
d. All of the above
17. The two factors that control the biologic productivity of a given area of the ocean are sunlight
availability and nutrient content.
a. True
b. False
The Dynamic Ocean
18. Deep-ocean circulation is sometimes called ___ circulation.
a. Pycnohaline
b. Gyrohaline
c. Thermohaline
d. Coriohaline
19. What is a gyre?
a. A loop of connected surface currents
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b. A loop of connected deep-ocean (thermohaline) currents
c. A narrow connection between a restricted ocean basin and the open ocean
d. An upwelling of cold, nutrient-rich water
20. What is the direct cause of the ocean’s surface currents?
a. Vertical circulation
b. Wind
c. Salinity variations
d. Density variations
21. In terms of heat energy, what do surface currents do?
a. They bring heat from polar latitudes towards the equator
b. They bring heat from the equatorial regions toward the poles
c. They move heat from colder to warmer areas
d. They do not affect the distribution of surface heat at all
22. Deep-ocean circulation would not occur without the presence of denser water on top of less dense
water, with the result that the denser water sinks. In what part of the world ocean does this occur?
a. Deep polar ocean
b. Tropical ocean surface
c. Deep tropical ocean
d. Polar ocean surface
23. 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 there are frequent upwellings of warm water from the deep ocean just off the
coast of Britain
c. Because the Gulf Stream brings warm tropical water to the British Isles, and not to
Canada
d. Because the jet stream brings warm tropical air up to the British Isles from the Gulf of
Mexico
24. What do all types of waves do?
a. Move water
b. Produce surface currents
c. Propagate energy
d. Drive deep-ocean circulation
25. In deep-ocean circulation, water movement is driven by variations in what property of the water?
a. Velocity
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b. Depth
c. Density
d. Latitude
26. On what time scale does deep-ocean circulation occur?
a. Centuries
b. Weeks
c. Months
d. Days
Match the parts of a wave to the correct letters on the diagram below:
27. Amplitude (wave height)
28. Wavelength
29. Trough
30. Wave base
31. Crest
B
C
D
E
A
32. If a wave’s wavelength is 30 meters, what is its wave base?
a. 30 meters
b. 15 meters
c. 10 meters
d. 20 meters
33. What causes ocean waves to break when they reach shore?
a. The wave becomes too small and expends all of its energy
b. Too much sediment piles up within the wave, making it unstable
c. The ocean bottom becomes shallower than wave base
d. All of the above
34. In deep water, the water undergoes net movement when a wave passes through.
a. True
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b. False
35. Which geometric shape represents the motion of a water molecule as a wave passes in deep water?
a. Oval
b. Sphere
c. Ellipse
d. Circle
The World Ocean & The Ocean Floor
36. Why are many areas of the ocean floor very flat, even though the topography of their bedrock is
frequently very rugged?
a. Bedrock has been eroded flat
b. Bedrock has been covered with molten rock from undersea volcanoes
c. Bedrock has been buried by sediment
d. It is not known why
37. Which of the following bathymetric techniques is capable of penetrating ocean floor sediment and
providing a view of bedrock topography?
a. High-resolution multibeam sonar
b. Seismic reflection profiling
c. Echo sounding
d. Weighted droplines
38. Sonar-based bathymetric techniques use sound waves to study the ocean floor’s topography.
a. True
b. False
Match each ocean basin with the correct letter on the map below:
39. Atlantic
B
40. Indian
D
41. Pacific
A
42. Arctic
C
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Match the parts of a passive margin listed below with the correct letters on the diagram:
43. Rise C
44. Shelf A
45. Slope B
46. Which of the following is a geologic process that occurs at mid-ocean ridges?
a. Creation of new crust
b. Evaporation
c. Precipitation
d. All of the above
47. The deepest parts of the world’s ocean basins are the
a. Trenches
b. Mid-ocean ridges
c. Continental shelves
d. Continental slopes
48. On this diagram of a mid-ocean ridge, which location would have the coldest rock? C
49. Which of the following does not accurately describe oceanic ridges?
a. Elevated because the rock composing them is warm and buoyant
b. Form a continuous, interconnected worldwide system
c. Ocean crust is destroyed there
d. Exhibit rift valleys at their centers
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