Deck 8: Ocean Circulation

Question 1

The Canary Current is an example of a(n):

A) shallow, cold water current.
B) deep, cold water current.
C) warm, southerly current.
D) mesopelagic current.

Answer 1

A

Question 2

A transverse current is:

A) a bottom current flowing in the same direction as an overlying surface current.
B) a surface current that connects eastern-boundary and western-boundary currents.
C) a cold surface current that flows from the poles towards the equator.
D) a theoretical current not yet discovered.

Answer 2

B

Question 3

The immediate source of surface currents is:

A) weather.
B) wind.
C) the sun.
D) the tides.

Answer 3

B

Question 4

El Niño results due to an interruption of flow of the ____ Current in the Pacific.

A) Kuroshio
B) Equatorial
C) Canary
D) Antarctic Circumpolar

Question 5

A system of four currents completing a flow circuit around the periphery of an ocean basin is collectively called:

A) a cell.
B) a gyre.
C) a microscale current.
D) convection cells.

Question 6

The only ocean current that continues in an uninterrupted circle around the circumference of the Earth without encountering land is the:

A) Gulf Stream.
B) Kuroshio, or Japan, Current.
C) Antarctic Circumpolar Current.
D) Canary Current.

Question 7

The Earth's rotation influences currents by a "force" known as:

A) Ekman spiral.
B) geostrophism.
C) gyre counter rotation.
D) Coriolis effect.

Question 8

Which of these is generally not an El Niño effect?

A) A decline in the exotic species of fish and other forms of marine life in the affected waters.
B) An increase in ocean surface temperature in the eastern Pacific.
C) An increase in rainfall in west coastal countries or states of the American continents.
D) An often catastrophic decrease in the commercial fisheries of the affected countries.

Question 9

Which of the following statements is FALSE considering thermohaline circulation?

A) Thermohaline circulation is caused by even and steady global heating of the ocean.
B) Thermohaline circulation is the result of heating of the ocean at lower latitudes and cooling at high latitudes.
C) Thermohaline circulation is driven by density gradients.
D) Thermohaline circulation transports tropical waters to polar regions.

Question 10

The densest water in ocean currents is the:

A) warmest and saltiest.
B) coldest and saltiest.
C) warmest and freshest.
D) coldest and freshest.

Question 11

England's weather is ____ than would be expected at that latitude because of the influence of surface currents.

A) colder
B) drier
C) less humid
D) warmer and wetter

Question 12

The ultimate source of most of the energy for ocean currents is:

A) weather.
B) wind.
C) the sun.
D) the tides.

Question 13

Generally the fastest and deepest ocean currents are:

A) northern boundary currents.
B) eastern boundary currents.
C) western boundary currents.
D) southern boundary currents.

Question 14

San Francisco's characteristic cold and foggy weather is caused by a:

A) cold eastern boundary current.
B) warm eastern boundary current.
C) cold western boundary current.
D) warm western boundary current.

Question 15

Which current within a northern hemisphere gyre would you expect to have the lowest salinity and temperature?

A) a western boundary current.
B) an eastern boundary current.
C) a southern boundary current.
D) a northern boundary current.

Question 16

North Atlantic Deep Water generally moves ____ than the surface currents above, and flows in ____ direction as the Gulf Stream.

A) faster; the same
B) faster; the opposite
C) slower; the same
D) slower; the opposite

Question 17

All of the following statements are true about an Ekman spiral EXCEPT:

A) the net flow of a wind-driven surface current in the northern hemisphere will flow about 90° angle to the wind.
B) with increasing depth, each layer will move at an angle to the overlying layer of water.
C) because of Ekman transport, at some depth, known as the friction depth, water will be moving in the opposite direction from the surface current.
D) Ekman spiral is not influenced by Coriolis.

Question 18

Currents tend to move in large ____ patterns in the northern hemisphere.

A) irregular
B) counterclockwise
C) clockwise
D) random

Question 19

Which ocean surface current transports the greatest volume of water?

A) The Kuroshio (or Japan) Current
B) The North Equatorial Current in the Pacific
C) The South Equatorial Current in the Pacific
D) The Antarctic Circumpolar Current

Question 20

All of the following statements accurately describe Geostrophic gyres EXCEPT:

A) One of the 6 gyres is the Antarctic Circumpolar Current.
B) Gyres are influenced by the Coriolis effect and the position of continental land masses.
C) Gyres are formed by surface currents that flow in a continuous circuit around the 5 major basins.
D) Sea level is higher in the middle of the gyre as a result of the pressure gradient and the Coriolis Effect.

Question 21

Surface water extends to a depth of about _________.

A) 600 meters
B) 1,000 meters
C) 50 meters
D) 200 meters

Question 22

Surface winds move across most of the tropical Pacific in a _____________ direction.

A) northeast
B) west to east
C) east to west
D) northwest

Question 23

Geostrophic currents are primarily wind driven.

Question 24

The main force driving thermohaline circulation is:

A) wind.
B) Coriolis effect.
C) density.
D) electromagnetic attraction.

Question 25

A sverdrup (sv) is a measure of:

A) wind speed.
B) current speed and direction.
C) the volume of water transported in an ocean current.
D) the amount of heat transferred to water from the sun.

Question 26

The Kuroshio Current is an example of an eastern boundary current.

Question 27

Which of the following is NOT an eastern boundary current?

A) Canary Current
B) Benguela Current
C) Gulf Stream
D) West Australian Current

Question 28

Warm-core eddies are common in the North Pacific.

Question 29

Ocean gyres are asymmetrical because of the Coriolis effect.

Question 30

Upwelling areas are:

A) only found near the equator.
B) usually nutrient poor.
C) sometimes interrupted during El Niño years.
D) not affected by Ekman transport.

Question 31

Equatorial upwelling occurs in westward-flowing equatorial surface currents.

Question 32

Most deep water masses form:

A) near the ocean floor in the arctic.
B) near the ocean floor in the Antarctic.
C) near the ocean surface in the arctic.
D) near the ocean surface in the Antarctic.

Question 33

One source of dissolved gases and nutrients to deep waters is:

A) downwelling.
B) upwelling.
C) conduction.
D) Langmuir Circulation.

Question 34

The largest of the western boundary currents is the:

A) Gulf Stream.
B) California Current.
C) East Pacific Gyre.
D) Canary Current.

Question 35

Thermohaline circulation is a _________ phenomenon.

A) small-scale
B) global
C) local
D) coastal

Question 36

The Gulf Stream is a current that runs south along the eastern coast of the United States.

Question 37

Transverse currents can flow eastward or westward.

Question 38

One example of horizontal water movement is called downwelling.

Question 39

The North Atlantic gyre is composed of the Gulf Stream, the North Atlantic Current, the Canary Current and the North Equatorial Current.

Question 40

Thermohaline circulation is responsible for large-scale movements of ocean water and depends on both the salinity and the temperature of water.

Question 41

What is ENSO?

Question 42

How do scientists study currents?

Question 43

Describe how ocean currents affect the global distribution of heat and give an example of how they moderate climate.

Question 44

Describe the two primary forces that set ocean water in motion and how they drive both surface and thermohaline currents.

Question 45

What is upwelling and why is it important for biological productivity?