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Ocean currents Power Point Slides

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trtkaren
trtkaren

Ocean currents are large streams of moving water that flow through the oceans and are capable of transporting large amounts of water over long distances. Surface currents are driven mainly by wind and circulate in gyres, while deep currents are caused by differences in water density from temperature and salinity changes. Upwelling occurs when winds cause colder, nutrient-rich water to rise up from the ocean depths, fueling areas of high biological productivity important for fisheries.

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Ocean Currents “Rivers in the Ocean”
Currents • Current – a large stream of moving water that flows through the ocean. Capable of moving large amounts of water long distances. • Surface Currents – Affect water to a depth of several hundred meters and are driven mainly by wind. – Currents move in circular patterns in each of the five major ocean basins.
Currents • Factors that affect currents – Sun’s heat – Earth’s winds – Earth’s rotation • Coriolis effect – the effect of Earth’s rotation on the direction of winds and currents – This is why currents in the Northern Hemisphere are clockwise, and those in the Southern Hemisphere run counter-clockwise
Gyres Explained http://youtu.be/CqZjvD_Xs4k
Currents • The largest and most powerful current in the North Atlantic Ocean is the Gulf Stream. – Caused by strong winds coming from the west (the same ones that move weather fronts from west to east) – More than 30 km wide and 300 m deep – Carries warm water up the East Coast Surface Current http://youtu.be/YCorkyBe66o
Currents • Deep Currents – caused by differences in density • rather than by surface winds Density of ocean water depends on two factors – Temperature (cold water = more dense = sinks to bottom) – Salinity (amount of salt, more salt = more dense = sinks to bottom) • Warm water surface currents move water from the equator toward the poles, where the water gets very cold.
Currents • As ice forms at the poles, the salinity of the water increases. • When temperature decreases and salinity increases, the density of the water increases. • This causes the water to sink to the bottom of the ocean floor. • Deep currents move much more slowly than surface currents.
Currents • Upwelling – the upward movement of colder water from the ocean depths. • Caused by the winds. – Wind blows the warm surface water away, causing cold water to rise up to replace it.
Currents • Upwelling also brings up – Tiny ocean organisms – Minerals – Other nutrients • Without this, the surface waters would have very little nutrients. • Upwelling zones are typically home to enormous schools of fish
Currents • One major area of upwelling is in the Pacific Ocean off of South America. • Upwelling occurs when strong winds from the Andes Mountains sweep across the ocean. – This creates a fishing area that is important to millions of people who depend on it for food and jobs.
Review • Surface Current - http://youtu.be/YCorkyBe66o
Quick Check Review • What are the two types of currents found in the ocean? • What is the Coriolis Effect? • What three things does upwelling bring to the surface?
Mr Parr’s Current Song • http://youtu.be/NsdH_NRM-CU

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Ocean currents Power Point Slides

  • 2. Currents • Current – a large stream of moving water that flows through the ocean. Capable of moving large amounts of water long distances. • Surface Currents – Affect water to a depth of several hundred meters and are driven mainly by wind. – Currents move in circular patterns in each of the five major ocean basins.
  • 3. Currents • Factors that affect currents – Sun’s heat – Earth’s winds – Earth’s rotation • Coriolis effect – the effect of Earth’s rotation on the direction of winds and currents – This is why currents in the Northern Hemisphere are clockwise, and those in the Southern Hemisphere run counter-clockwise
  • 5. Currents • The largest and most powerful current in the North Atlantic Ocean is the Gulf Stream. – Caused by strong winds coming from the west (the same ones that move weather fronts from west to east) – More than 30 km wide and 300 m deep – Carries warm water up the East Coast Surface Current http://youtu.be/YCorkyBe66o
  • 6. Currents • Deep Currents – caused by differences in density • rather than by surface winds Density of ocean water depends on two factors – Temperature (cold water = more dense = sinks to bottom) – Salinity (amount of salt, more salt = more dense = sinks to bottom) • Warm water surface currents move water from the equator toward the poles, where the water gets very cold.
  • 7. Currents • As ice forms at the poles, the salinity of the water increases. • When temperature decreases and salinity increases, the density of the water increases. • This causes the water to sink to the bottom of the ocean floor. • Deep currents move much more slowly than surface currents.
  • 8. Currents • Upwelling – the upward movement of colder water from the ocean depths. • Caused by the winds. – Wind blows the warm surface water away, causing cold water to rise up to replace it.
  • 9. Currents • Upwelling also brings up – Tiny ocean organisms – Minerals – Other nutrients • Without this, the surface waters would have very little nutrients. • Upwelling zones are typically home to enormous schools of fish
  • 10. Currents • One major area of upwelling is in the Pacific Ocean off of South America. • Upwelling occurs when strong winds from the Andes Mountains sweep across the ocean. – This creates a fishing area that is important to millions of people who depend on it for food and jobs.
  • 11. Review • Surface Current - http://youtu.be/YCorkyBe66o
  • 12. Quick Check Review • What are the two types of currents found in the ocean? • What is the Coriolis Effect? • What three things does upwelling bring to the surface?
  • 13. Mr Parr’s Current Song • http://youtu.be/NsdH_NRM-CU