Download 11.2 OCEAN CURRENTS

11.2 Ocean Currents – Student Notes
Ocean Currents
• There are more than _________________ which move large amounts of water predictably
around the oceans.
 Currents move large quantities of water, minerals, solar energy, oxygen and carbon
dioxide, plankton and fish.
 Currents are caused and driven by water density and salt content, the wind, the spin of
Earth, coastlines and the moon.
 Largest current is the ___________________________________ in the Southern Ocean,
at _________ long
• _______________ are either
 Surface currents (___________)
 Deep water currents (_______________)
What Makes Surface Currents Move?
• ___________________________
 As air warms from _______________________, it rises, and cooler air rushes to replace
it. This creates wind.
 As the wind passes along the surface of the water, it bumps the water molecules and
moves them along in the same ___________________.
• ___________________________
 Earth spins from West to East (counter clockwise)
 The________________ effect deflects winds and currents to the right/East in the
Northern hemisphere
(opposite in the Southern hemisphere)
• ____________________________
 Currents move through the oceans and around
the continents like rocks in a stream.
What Makes Deep Currents Move?
• ____________________________:
 Like air, warm water rises, and cool water falls
 ____________________________ = cool, dense water moving on an ocean floor.
 Three layers of water dependent on temperature:
 ________________: 0 - 200 m, warmest
 ________________: 200 m - 1 km, rapidly cools
 ________________: 1 km and deeper, just above freezing
• _____________________________:
 Adding fresh water decreases salinity
 Evaporation and freezing increases salinity
 Densest ocean waters at the poles
 __________________occurs when nutrient-rich
cold water finally moves up to the surface
Ocean Waves and Their Effect on Shaping Land
• Most waves are __________________________________.
• In open ocean, waves are called _______________.
• The largest waves are _________________, caused by undersea earthquakes, landslides or
volcanic eruptions.
• Waves erode coastal areas based on the force of the waves, and the composition of the
shoreline.
• ____________________made up of harder rock, and erode less, but absorb most wave force.
• ____________________ occur between headlands, are generally calm.
• ____________________ are extra-hard rock left behind from eroded headlands.
Tides
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•
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____________________ are caused by gravities of Earth and the Moon.
 High tides occur where the Moon is closest to Earth (and opposite side)
 Low tides occur at 90º to the high tides.
____________________ (difference between high and low) averages 3 m in BC.
The Sun’s gravity, when lined up properly, can produce extreme tides.
 These are called ______________________
 When the Sun, Moon and Earth are not lined up, the tides are called
___________________________.