Question 1

Which water mass is not produced by caballing?
A) North Atlantic Intermediate Water
B) Antarctic Intermediate Water
C) Antarctic Bottom Water
D) Mediterranean Deep Water

Accepted Answer

The Mediterranean Deep water is not produced by caballing. Some Antarctic Bottom Water is produced by caballing or the mixing and sinking of water masses. Information can be found in the section Thermohaline Circulation Affects All the Ocean's Water.

Question 2

What is La Niña?
A) A warmer than normal circulation event
B) A circulation due to density and salinity
C) A colder than normal circulation event
D) The result of volcanic eruptions

Accepted Answer

La Niña events are characterized by strong currents, powerful upwelling, and stormy conditions. These colder than normal events are the response to El Niño events. Information can be found in the section El Niño and La Niña Are Exceptions to Normal Wind and Current Flow.

Question 3

How many water masses are common in tropical and temperate latitudes?
A) Three
B) Four
C) Five
D) Six

Accepted Answer

The water masses present in temperate and tropical waters are named for their relative positions in the water column. These water masses are surface water, central water, intermediate, deep water, and bottom water. Information can be found in the section Thermohaline Circulation Affects All the Ocean's Water.

Question 4

What powers a Slocum glider?
A) Batteries
B) Photovoltaics
C) Currents
D) Gravitational energy, buoyancy, and heat

Accepted Answer

Slocum gliders are able to move up and down through a water column. It is powered by gravity and buoyancy. A heat powered engine pumps the water over the ballast of the glider. Information can be found in the section Studying Currents.

Question 5

What influences contour currents?
A) Salinity
B) Density
C) Topography
D) Trade winds

Accepted Answer

The dense flow of water goes around seafloor formations. Contour currents can be relatively fast. Information can be found in the section Thermohaline Circulation Affects All the Ocean's Water.

Question 6

What is responsible for the large-scale global ocean circulation?
A) Surface currents
B) ENSO events
C) Thermohaline circulation
D) Langmuir circulation

Accepted Answer

Thermohaline circulation is the movement of water due to density differences. The whole ocean is involved in this slow circulation. Information can be found in the section Thermohaline Circulation Affects All the Ocean's Water.

Question 7

If an eddy found in the Gulf Stream is rotating counterclockwise, then it is:
A) a warm water eddy.
B) a cold water eddy.
C) a transverse current.
D) an eastern boundary current.

Accepted Answer

An eddy is a turbulent ring that has cold or warm water trapped within its center. It becomes separate from the main flow of water. In the Gulf Stream, cold water eddies rotate counterclockwise while warm water eddies move clockwise. Information can be found in the section Surface Currents Are Driven by the Winds.

Question 8

Where is density stratification the least pronounced?
A) Temperate latitudes
B) Polar latitudes
C) Tropical latitudes
D) Areas where there is upwelling

Accepted Answer

Polar areas have smaller differences in temperature between the surface and deep water. The minimal difference causes the density stratification to be less pronounced than tropical and temperate regions. Information can be found in the section Thermohaline Circulation Affects All the Ocean's Water.

Question 9

What maintains the permanent thermocline found at all low and mid-latitudes?
A) Continual upwelling
B) Warm water currents
C) Density stratification
D) Downwelling

Accepted Answer

The thermohaline flow of water rises to the surface in temperate and tropical zones very gradually. It sinks back down rapidly once it is in the colder waters at the poles. This diffuse upwelling of deep water maintains the thermoclines. Information can be found in the section Thermohaline Circulation Affects All the Ocean's Water.

Question 10

What thrusts water masses that are engaged in the thermohaline flow of the world's ocean?
A) Density
B) Gravity
C) Trade winds
D) Coriolis Effect

Accepted Answer

The water masses are propelled by gravity. Water masses hit one another in convergence zones. The heavier water mass slides beneath the lighter water mass. Information can be found in the section Understanding the Ocean Began with Voyaging for Trade and Exploration.

Question 11

What is a characteristic of Antarctic Bottom Water?
A) Extreme density
B) The water moves south towards Antarctica along the seafloor
C) Fast moving
D) Most is produced near the Mediterranean and joins the deep bottom layer

Accepted Answer

The Antarctic Bottom water moves very slowly. It may take a thousand years to reach the equator, but it does move relatively faster in the Atlantic. This current has extreme density and is produced near Antarctica. Information can be found in the section Thermohaline Circulation Affects All the Ocean's Water.

Question 12

Why are fisheries heavily impacted by ENSO events?
A) Upwelling ceases
B) Nutrient-rich currents are interrupted when the trade winds shift
C) Low pressure systems create downwelling events rather than the normal upwelling
D) Rise in sea level effects migration patterns

Accepted Answer

The northward flow of nutrient-rich waters is interrupted by warm water masses with little nutrients. Some upwelling does still occur, but there are no nutrients to bring to the surface. Information can be found in the section Marine Scientists Use the Logic of Science to Study the Ocean.

Question 13

What is not a characteristic of an El Niño Southern Oscillation (ESNO)?
A) High pressure area shifts to the western Pacific
B) Trade winds across the Pacific weaken or reverse directions
C) Equatorial currents stop
D) Trade winds across the Pacific strengthen

Accepted Answer

The high pressure system that is normally positioned in the eastern Pacific shifts to the western Pacific. The trade winds begin to weaken or even reverse direction. The warm waters then begin to move east around December. Information can be found in the section El Niño and La Niña Are Exceptions to Normal Wind and Current Flow.

Question 14

What does not affect surface currents?
A) Gravity
B) Coriolis Effect
C) Wind
D) Density

Accepted Answer

Wind allows water flow to start in surface currents. The water "piles up" in the direction the wind blows. Gravity pulls the water down the slope the water creates when piled up. The Coriolis Effect deflects the moving mass of water to the left or right depending on the hemisphere. Information can be found in the section Surface Currents Are Driven by the Winds.

Question 15

What is not a characteristic of western boundary currents?
A) They move warm water poleward.
B) They are fast moving currents.
C) They are deep currents.
D) They are broad currents.

Accepted Answer

Western boundary currents are narrow, deep, and fast moving currents. They have clearly defined boundaries. There are five large western boundary currents. Information can be found in the section Surface Currents Are Driven by the Winds.

Question 16

What is another name for undercurrents?
A) Equatorial currents
B) Transverse currents
C) Countercurrents
D) Subterranean currents

Accepted Answer

Countercurrents typically accompany equatorial currents. They flow on the surface in the opposite direction of the main current. They can be quite large. Information can be found in the section Surface Currents Are Driven by the Winds.

Question 17

What is considered to be the largest western boundary current?
A) Canary Current
B) Gulf Stream
C) Brazil Current
D) East Australian Current

Accepted Answer

The Gulf Stream is the largest western boundary current. It has a width of approximately 70 kilometers and moves at an average speed of 5 miles per hour. Information can be found in the section Surface Currents Are Driven by the Winds.

Question 18

What is the name for slow, deep currents beneath the pycnocline?
A) Surface currents
B) Convection currents
C) Thermohaline currents
D) Polar currents

Accepted Answer

Thermohaline currents are dependent on density differences which stem from temperature and salinity variations. These and surface currents have large impacts on Earth's temperature, climate and biological activity. Information can be found in the section Mass Flow of Ocean Water Is Driven by Wind and Gravity.

Question 19

What is used to visualize ocean layering?
A) A caballing chart
B) A circulation histogram
C) A layering table
D) A temperature-salinity diagram

Accepted Answer

There are many combinations of temperature and salinity that can yield the same density. Layers in the ocean are dictated by density. Water masses with the same density but different temperature and salinity can combine to produce a new water mass with greater density. Information can be found in the section Thermohaline Circulation Affects All the Ocean's Water.

Question 20

What mechanism is being used to gain new information regarding deep sea circulation?
A) Acoustic tomography
B) ACDP systems
C) Electromagnetic field detectors
D) Drift cards

Accepted Answer

Acoustic tomography uses low frequency pulses of sound to detect variations in temperature, salinity, and movement beneath the surface. Information can be found in the section Studying Currents.

Quiz 9: Circulation of the Ocean

Which water mass is not produced by caballing?

What is La Niña?

How many water masses are common in tropical and temperate latitudes?

What powers a Slocum glider?

What influences contour currents?

What is responsible for the large-scale global ocean circulation?

If an eddy found in the Gulf Stream is rotating counterclockwise, then it is:

Where is density stratification the least pronounced?

What maintains the permanent thermocline found at all low and mid-latitudes?

What thrusts water masses that are engaged in the thermohaline flow of the world's ocean?

What is a characteristic of Antarctic Bottom Water?

Why are fisheries heavily impacted by ENSO events?

What is not a characteristic of an El Niño Southern Oscillation (ESNO) ?

What does not affect surface currents?

What is not a characteristic of western boundary currents?

What is another name for undercurrents?

What is considered to be the largest western boundary current?

What is the name for slow, deep currents beneath the pycnocline?

What is used to visualize ocean layering?

What mechanism is being used to gain new information regarding deep sea circulation?