Test Bank Answers Ocean Structure And Circulation Chapter 7

Investigating Oceanography, 3e (Sverdrup)

Chapter 7 Ocean Structure and Circulation

1) Wind blowing across the sea surface can create paired right- and left-handed circulation cells knows as ________ cells, leading to parallel zones of surface convergence and divergence.

2) Meanders in the Gulf Stream current can pinch off to form warm and cold core ________.

3) Wind-driven surface water moves in a complex manner as a function of depth. This is called the ________.

4) Many combinations of salinity and temperature of seawater can produce the same density of seawater.

5) Water of a lower density usually lies below water of a greater density.

6) In the oceans, the zone where density of water changes rapidly with depth is called a pycnocline.

7) Usually temperature, salinity, and pressure distributions cause ocean water density to increase with depth.

8) The pycnocline of the oceans is usually found at depths exceeding 2000 m.

9) In an area where surface currents converge, the water upwells.

10) The properties of seawater at depth are determined by surface conditions in the area where the water sinks.

11) Antarctic bottom water has a very narrow range of both salinity and temperature; this water is nearly homogeneous.

12) A water mass at depth in the ocean has temperatures and salinities that are usually determined by the conditions present when the water mass was last at the sea surface.

13) The density of Arctic Ocean water is controlled more by salinity than by temperature.

14) Increasing salinity increases density.

15) Increasing temperature also increases density.

16) The pycnocline is an area where temperature changes rapidly with depth.

17) Isothermal water is stable and does not overturn.

18) Temperature affects density in the Arctic Ocean more than salinity.

19) The density of Mediterranean Intermediate Water is influenced more by salinity than temperature.

20) The large ocean surface-current gyres centered on about 30°N ________.

A) rotate counterclockwise

B) do not rotate

C) have depressed surface elevations

D) rotate clockwise

E) alternate their direction of rotation with the seasons

21) A surface gyre system in the Southern Hemisphere ________.

A) promotes upwelling and surface depression if it rotates clockwise

B) promotes upwelling and surface elevation if it rotates counterclockwise

C) retards upwelling and decreases surface elevation if rotating counterclockwise

D) retards upwelling and increases surface elevation if rotating counterclockwise

E) Rotation in either direction does not affect upwelling.

22) Layering in the ocean occurs because ________.

A) surface processes form water layers of differing combinations of salinity and temperature

B) processes at depth add and subtract salt and heat

C) atmospheric processes control conditions at the surface

D) surface processes form water layers of differing combinations of salinity and temperature and atmospheric processes control conditions at the surface

E) All of these choices are correct.

23) A rapid change in temperature with depth is called a ________.

A) halocline

B) thermocline

C) photic level

D) midwater current

E) pycnocline

24) If the density of the water increases with depth, the water column is ________.

A) stagnant

B) unstable

C) stable

D) neutral

E) well mixed

25) If extremely cold fresh water is added on top of seawater, ________.

A) the cold water will float at the surface

B) the cold water will sink to the bottom and stagnate

C) the cold water will sink and move rapidly out of the area

D) an overturn will begin immediately

E) the wind will control the surface mixing

26) A good example of thermohaline circulation is found ________.

A) in equatorial regions

B) in the central South Pacific

C) close to Antarctica

D) along the east coast of the United States

E) in the Gulf of Mexico

27) Thermohaline circulation is driven by changes in ________.

A) viscosity

B) surface tension

C) convection

D) pressure

E) density

28) Sigma–t is the oceanographers short-hand for the density of seawater. It is defined as (density − 1.0) × . If the density of seawater is 1.02925 g/cm3, the sigma–t value is

A) 25.29.

B) 2.9925.

C) 0.2925.

D) 29.25.

E) 0.02529.

29) In areas of downwelling, a near-surface ________ is unlikely.

A) halocline.

B) pycnocline.

C) thermocline.

D) All of these are correct.

E) None of these is correct.

30) The coldest, deepest, densest water in the oceans ________.

A) is formed around Antarctica

B) flows north

C) is Antarctic bottom water

D) All of these are correct.

E) None of these is correct.

31) North Atlantic deep water ________.

A) flows to the south

B) rises toward the surface in the Southern Ocean

C) is formed off Labrador

D) All of these are correct.

E) None of these is correct.

32) Deep-ocean water in the Atlantic Ocean flows mainly ________.

A) east-west

B) north-south

C) to the right

D) to the left

E) None of these is correct; there is no deep-water flow.

33) A water type having both high salinity and warm temperature but dense enough to be found at about 1000 m in the central North Atlantic has been formed ________.

A) in equatorial regions

B) in the Red Sea

C) in the Mediterranean Sea

D) near Greenland

E) in the Caribbean Sea

34) The water type occupying the greatest volume of the Atlantic Ocean is ________.

A) Antarctic bottom water

B) Antarctic intermediate water

C) circumpolar Antarctic water

D) North Atlantic deep water

E) surface water

35) Which of the following are affected by the density of the surface water?

A) Transparency

B) Density layering

C) Convective overturn

D) Density layering and convective overturn

E) All of these are correct.

36) If two surface water types with the same density but different salinities and temperatures mix, the resulting water will be ________.

A) denser than both parent types

B) less dense than both parent types

C) denser than the more dense parent type

D) less dense than the less dense parent type

E) the same density as the parent types

37) The thermocline found in water above 500 m at temperate latitudes disappears and the water column becomes neutral in ________.

A) spring

B) summer

C) fall

D) winter

E) None of these is correct; it does not disappear.

38) If very warm and salty sea water is added on top of average seawater, ________.

A) the warm salty water will float at the surface

B) the warm salty water will sink to the bottom and stagnate

C) the warm salty water will sink and move rapidly out of the area

D) an overturn will begin

E) The answer cannot be determined unless the densities of the warm salty water and average sea water are known.

39) Order the following water bodies from highest to lowest salinity.

A) Mediterranean intermediate water, North Atlantic deep water, Antarctic bottom water

B) North Atlantic deep water, Mediterranean intermediate water, Antarctic bottom water

C) Antarctic bottom water, Mediterranean intermediate water, North Atlantic deep water

D) Mediterranean intermediate water, Antarctic bottom water, North Atlantic deep water

E) Antarctic bottom water, North Atlantic deep water, Mediterranean intermediate water

40) The South Equatorial current of the Pacific Ocean moves surface water from the Southern Hemisphere to the Northern Hemisphere.

41) Currents in the northern Indian Ocean change direction seasonally.

42) The Indian Ocean gyre rotates counterclockwise.

43) Prevailing westerly winds cause easterly currents.

44) The Ekman Spiral causes current speed to increase with depth.

45) The sea surface at the center of the Sargasso Sea is depressed.

46) Eddies are found at all depths of the oceans.

47) Surface eddies can be tracked by satellites.

48) Southern Hemisphere winds move surface water 90 degrees to the left of the direction of the wind.

49) Downwelling is produced by diverging surface currents.

50) Downwellings occur at surface convergences.

51) Upwelling along the coast of Peru is very seasonal, due to the continually shifting wind patterns.

52) The North Atlantic gyre rotates counterclockwise.

53) Geostrophic flow occurs when the Coriolis deflection is balanced by an opposite gravitational flow.

54) The clockwise gyre of the Arctic Ocean is driven by the polar easterlies.

55) Ocean currents are deflected to a greater degree by the Coriolis effect than by wind systems.

56) A convergence of water occurs at the eastern side of each of the main ocean basins as a result of Ekman transport.

57) Upwelling occurs along the coast of California when winds blow from the north.

58) The highly productive seas along the equator are the result of the tropical convergence located there.

59) In the Northern Hemisphere, the water surface of the open ocean moves ________.

A) at right angles to the wind

B) against the wind

C) parallel to the wind

D) 45 degrees to the right of the wind

E) 45 degrees to the left of the wind

60) A south wind produces a ________ surface current in the Northern Hemisphere.

A) northern

B) southwest

C) northwest

D) southeast

E) northeast

61) The southeast trade winds directly produce the ________ current.

A) Gulf Stream

B) Equatorial Counter

C) South Equatorial

D) West Wind Drift

E) East Australia

62) The North Atlantic current is produced by the ________.

A) northeast trade winds

B) southeast trade winds

C) prevailing westerlies

D) polar easterlies

E) seasonal monsoon

63) The average movement of all water affected by the wind is ________ degrees to the ________ of the wind motion in the Southern Hemisphere.

A) 45; right

B) 45; left

C) 90; right

D) 90; left

E) 180; no direction

64) When geostrophic flow is achieved, the ________ force is balanced by the ________ force.

A) centrifugal; centripetal

B) Coriolis; centrifugal

C) Coriolis, gravitational

D) gravitational; centrifugal

E) centripetal; centrifugal

65) The current at the eastern boundary of the Sargasso Sea is the ________ Current.

A) Gulf Stream

B) North Equatorial

C) Canary

D) Greenland

E) Labrador

66) Currents are more intense on the ________ side of the North Pacific and North Atlantic Oceans.

A) northern

B) southern

C) eastern

D) western

E) None of these is correct; they are not more intense on one side.

67) The Gulf Stream forms eddies, or rings, with cold water cores at the ________ edge of the Gulf Stream current.

A) northern

B) southern

C) eastern

D) western

E) either eastern or western

68) A zone of surface divergence is an area of ________ and ________ biological productivity.

A) upwelling; high

B) upwelling; low

C) downwelling; high

D) downwelling; low

E) no vertical motion; average

69) A seasonal north wind blowing along the west coast of a landmass in the Northern Hemisphere produces ________.

A) downwelling in winter

B) downwelling in summer

C) upwelling in winter

D) upwelling in summer

E) overturn in all seasons

70) Prevailing ________ winds are needed to provide the net movement of surface water seaward along the west coast of North America.

A) northerly

B) easterly

C) westerly

D) southerly

E) seasonal coastal

71) In the Southern Hemisphere, the speed of the wind-driven water ________ with depth and the water moves to the ________ of the wind.

A) increases; right

B) increases; left

C) decreases; right

D) decreases; left

E) does not change; left

72) Which current flows south along the west coast of the United States?

A) North Pacific

B) California

C) Japanese

D) Gulf Stream

E) Kuroshio

73) A south wind produces a ________ flowing surface current in the Southern Hemisphere.

A) northwest

B) northeast

C) south

D) southwest

E) southeast

74) A doppler current meter shows an increase in sound frequency if the water flow is ________.

A) moving away from the meter

B) moving toward the meter

C) moving around the meter

D) increasing

E) decreasing

75) A current meter measures water's ________.

A) speed

B) viscosity

C) direction

D) speed and viscosity

E) speed and direction

76) Currents are less intense on the ________ side of the North Pacific and North Atlantic oceans.

A) north

B) south

C) east

D) west

E) None of these is correct; they are not more intense on one side.

77) The Atlantic prevailing westerlies drive the ________.

A) Gulf Stream and Canary currents

B) North Atlantic and West Wind Drift

C) Brazil and Benguela currents

D) North and South Equatorial currents

E) None of these is correct.

78) Which current moves cold water to warm latitudes?

A) Gulf Stream

B) Kuroshio

C) Peru

D) Agulhas

E) Brazil

79) Which current flows north to south along the northeast coast of the United States?

A) Gulf Stream

B) Labrador

C) Canary

D) North Equatorial

E) North Atlantic

80) The speed of the Florida current is high because ________.

A) the winds are strong at this latitude

B) the water has a high salinity

C) the channel through which it flows is narrow

D) the Coriolis effect is large

E) None of these is correct; it is a slow current.

81) Eddies ________.

A) persist for long periods of time

B) mix water

C) lost energy to turbulence

D) stir up bottom sediments

E) All of these are correct.

82) The single most important source of deep water to all of the world's oceans is ________.

A) downwelling in the North Atlantic

B) Antarctic intermediate water

C) subduction in all oceans

D) the Peru current along the South American coast

E) Antarctic intermediate water and the Peru current along the South American coast

83) Oil tankers coming from the Persian Gulf to the United States use the ________ current along the east coast of Africa.

A) Canary

B) Guinea

C) Agulhas

D) Benguela

E) South Equatorial

84) Wind-driven surface currents move at a speed that is ________ the average driving wind speed.

A) the same as

B) one tenth

C) one one-hundredth

D) twice

E) None of these is correct; there is no relationship.

85) The Equatorial Counter current ________.

A) flows from east to west

B) flows between the North Pacific and Alaska currents

C) is not present in the Indian Ocean

D) lies between the North and South Equatorial currents

E) is a cold water current

86) The Arctic Ocean receives ________.

A) North Atlantic water from the Labrador Current

B) North Atlantic water from the Norwegian current

C) North Pacific water through the Bering Strait

D) North Atlantic water from the Labrador Current and North Atlantic water from the Norwegian current

E) North Atlantic water from the Norwegian current and North Pacific water through the Bering Strait

87) Which of the following is NOT true about the influence of Ekman transport on surface currents?

A) The effect extends to a depth of approximately 100 to 150 m below sea level.

B) The average flow of water is 90 degrees to the direction of wind.

C) Each subsequent layer of water moves more quickly than the one above it.

D) Surface waters move 45 degrees to the direction of wind.

E) All of these statements are true.

88) In the midlatitudes, in both hemispheres, warm currents flow past the ________ coasts of continents.

A) east

B) west

C) north

D) south

E) It depends on the continent.

89) Of the major ocean gyres, cool currents are ________.

A) eastern boundary currents

B) western boundary currents

C) equatorial currents

D) northern boundary currents

E) It depends on the ocean basin.

90) Which of the following is the most common range of speeds for surface currents?

A) 0.1 to 0.2 knots

B) 0.25 to 1.0 knots

C) 3 to 5 knots

D) 10 to 15 knots

E) 100 to 150 knots

91) Which of the following currents is western intensified?

A) California Current

B) Gulf Stream

C) West Wind Drift

D) All of these are correct.

E) None of these is correct.

92) A rapid change in salinity with depth is called a ________.

A) halocline

B) thermocline

C) photic level

D) midwater current

E) pycnocline

93) A rapid change in density with depth is called a ________.

A) halocline

B) thermocline

C) photic level

D) midwater current

E) pycnocline

94) Which current moves warm water to colder latitudes?

A) Gulf Stream

B) Kuroshio

C) Agulhas

D) None of these is correct.

E) All of these are correct.

95) Which of the following has the highest density?

A) 1037 kg/m3

B) sigma-t = 26.4

C) 1011.7 kg/m3

D) 1.039 g/cm3

E) sigma-t = 13.6

96) An average value for the salinity of seawater could be (pick the best choice) ________.

A) 15 g/kg

B) 20 g/kg

C) 25 g/kg

D) 30 g/kg

E) 35 g/kg

97) An average value for the density of seawater could be (pick the best choice) ________.

A) 1.025 g/cm3

B) 1.010 g/cm3

C) 1.012 g/cm3

D) 2.020 g/cm3

E) 1.050 g/cm3

98) An average value for the temperature of deep-ocean water is (pick the best choice) ________.

A) –4.5°C

B) 2°C

C) 8°C

D) 12°C

E) 17°C

99) The Kuroshio is NOT ________.

A) a western boundary current

B) fast

C) deep

D) cold

E) narrow

100) The large ocean gyres are characterized by ________.

A) lower sea levels inwards than outwards

B) ekman transport driving water outwards

C) gravity-driven transport driving water inwards

D) greater current velocities inwards

E) higher salinities inwards

101) In which one of the following cases will coastal upwelling occur?

A) Wind blowing from south to north along the Georgia coast

B) Wind blowing from north to south along the Delaware coast

C) Wind blowing from south to north along the Oregon coast

D) Wind blowing from north to south along the South Carolina coast

E) In none of these cases