OCE 1001 Chapter 7

Recall that global winds impact the direction of surface ocean currents. Examine the following map showing the Atlantic Ocean off the west coast of Africa. The direction of the surface current and the prevailing wind do not coincide. What can explain this discrepancy?

-Because the current is located in the Southern Hemisphere, the subtropical gyre pulls the current in a counterclockwise direction. -The Coriolis effect deflects ocean currents in the Southern Hemisphere to the left due to Earth's rotation.

Of the following conditions, which is/are related to strong El Niño events?

-Higher sea levels in the eastern Pacific Ocean associated with warmer water -Increased abundance of hurricanes in the eastern Pacific Ocean -Increase in sea-surface temperatures and destruction of coral reefs in the eastern Pacific Ocean

Of the following methods, which are indirect methods for measuring currents?

-Pressure gradients -Dynamic topography -Doppler flow meter

Of the following gyres, which one(s) flow in a counterclockwise direction?

-South Pacific Subtropical Gyre -Northern Hemisphere Subpolar Gyres -South Atlantic Subtropical Gyre -Indian Ocean Subtropical Gyre

Of the following locations, where would upwelling be expected to occur?

-Where there is a sharp bend in a coastline -Where seamounts or tablemounts are present -In areas of diverging surface currents

What percentage of an icebergs mass is below the waterline?

90%

Western intensification causes:

All the above effects are the result of western intensification.

Which of the following is the only current that completely circumscribes Earth?

Antarctic Circumpolar

Which of the following currents contributes to the South Western United States being arid?

California Current

Which of the following is true for downwelling?

Carries dissolved oxygen to the deep-sea floor

The California Current is an example of which of the following types of currents?

Eastern Boundary Current

The world's two main iceberg-producing regions are ________.

Greenland and Antarctica

Which of the following currents contributes to the South Eastern United States being humid?

Gulf Stream

Which swift-flowing surface current in a major subtropical gyre transports a large volume of warm water from the equator toward the mid-latitudes?

Kuroshio Current

Palm trees associated with the subtropics can be found at the northern tip of the British Isles in Scotland. This is due to the transfer of heat from the ____________________

North Atlantic current

The North Atlantic Current is an example of which of the following types of currents?

Northern Boundary Current

Which of the following methods are used to measure ocean surface currents directly?

Radio-transmitting float bottles

The West Wind Drift is an example of which of the following types of currents?

Southern Boundary Current

The deepest and densest water mass in the world ocean is formed in the __________________.

Southern Ocean

The observation of a hill of water within all subtropical gyres is an example of which of the following?

Subtropical convergence

In a severe warm phase of the El Niño-Southern Oscillation (ENSO), fisheries' productivity on the west coasts of the Americas is dramatically reduced. Which stage of ENSO would come just before the fisheries' collapse?

The thermocline deepens in eastern boundary currents of the Pacific Ocean subtropical gyres.

___________________ is caused by density changes near the poles and equator.

Thermohaline circulation

Which of the following is true of surface water circulation near Antarctica?

Two circumpolar currents dominate it, one current that moves water to the east and one current that moves water to the west.

What depth does Argo floats collect data?

Upper 2000 meters

The Agulhas Current is an example of which of the following types of currents?

Western Boundary Current

Peru's residents are familiar with ENSO as it brings a warm current that reduces populations of which animal?

anchovies

Waters along the California coast are colder than those along the mid-Atlantic shore of the U.S. because ________________ occurs as surface waters move away from the coast.

coastal upwelling

Which conditions in the ocean promote high productivity?

cold water, rich nutrients

Downwelling can result from __________.

converging surface currents

Deep ocean currents are driven primarily by ________ .

density differences

Which method would be most appropriate for directly measuring the flow rate of the Gulf Stream?

drift bottles

The area in the enclosed rectangle in the false-color map of sea surface temperatures is an example of which of the following features?

eddies

During winter months, monsoon winds over the Indian Ocean ________.

flow from land to sea and are dry

Which type of current flow moves in a circular path around a subtropical convergence, reflecting Ekman transport, gravity, and the Coriolis effect?

geostrophic circulation

Freezing seawater at ________________ leads to increases in salinity and density.

high latitudes

Deep-water currents move ________ volumes of water and are much ________ than surface currents.

larger; slower

Ocean surface currents transfer about ________ of the total amount of heat from the tropics to the poles.

one-third

Which of the following is a direct method for measuring surface currents?

propeller flow meter

Records indicate that the ocean is warming faster in the Arctic polar regions than elsewhere. If that continues, a possible consequence could be __________.

slowing of deep-ocean circulation, resulting in lower oxygen levels in deep water

The thickness of sea ice is limited primarily by __________.

the insulating nature of the ice itself

The El Niño Southern Oscillation can best be described as:

the relationship between sea surface temperature and changing atmospheric pressure.

The Ekman spiral is caused by:

the wind and the Coriolis effect.

Equatorial currents are driven by the:

trade winds

Surface waters are pushed away from land and replaced by nutrient-rich bottom water through:

upwelling

Diverging surface waters are areas of ________ and ________ productivity.

upwelling; high

Surface ocean currents are driven primarily by ________ and modified by ________.

wind; the Coriolis effect and land