Ocean Currents

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Ocean Currents
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Ocean Currents

• Mass movement or flow of ocean water
• River within the ocean (Conveyor Belt)
• Two types
• Surface
• Deep (or Subsurface)

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Ocean Currents Vocabulary
Gyre Nearly closed current system in the open
ocean

• Clockwise pattern in N. Hemisphere
• Counter-clockwise pattern in S. Hemisphere

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Ocean Currents Vocabulary Continued

• Meander Bend in a currents flow
• Ring Large, whirl-like pattern (when a meander
  is cut off)
• Eddy Small current Ring

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Surface Current Link

• Horizontal, stream-like movements of water that
  occur at or near the surface of the ocean
• Can reach depths of several hundred meters

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Surface Currents continued

• Controlled by three factors
• Global winds
• Coriolis Effect
• Continental Deflections

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Surface Currents continued

• Global Winds
• Cause surface currents to flow in the direction
  the wind is blowing
• Coriolis Effect Link
• Apparent curving of moving objects (ie- Water)
  due to the Earths rotation

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Surface Currents continued

• Coriolis Effect
• Northern Hemisphere clockwise
• Southern Hemisphere counter clockwise
• Continental Deflections
• Shape of continents change the direction of
  current flow

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Deep Currents

• Stream like movement of ocean water far below
  the surface
• Caused by changes in density
• Change in temperature
• Change in salinity

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Deep Currents continued

• Change in temperature
• Decreasing the temperature of water increases
  density
• Change in salinity
• Increasing the salinity of water increases
  density

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Surface currents and climate

• Warm water currents
• On the east coasts of continents
• Bring warm water to colder regions

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Surface currents and climate

• Cold water currents
• On the west coasts of continents
• Bring cold water to warmer regions

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Upwelling Link

• The movement of deep, cold, nutrient rich water
  to the surface
• Nutrients promote growth of fish and plants
• Areas are important fishing grounds

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Downwelling

• The movement of warm surface waters towards the
  coast
• Causes a thickening of the surface waters which
  causes them to sink

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Causes of warm and cold currents

• El Niño
• Change in the water temperature in the Pacific
  Ocean that produces a warm current

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Causes of warm and cold currents

• La Niña
• Change in the eastern Pacific Ocean in which the
  surface water temperature becomes unusually cool

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