Ocean Currents

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Bell work
Given the average yearly temperatures for the
Sicily Isles in England and Newfoundland in
Canada, can you explain why the two locations
have very different year-round temperatures? Note
their locations on a globe/map, and use what you
know about the movement of ocean currents to
support your answer.
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Objectives for today!

• Describe surface currents.
• List the three factors that control surface
  currents.
• Describe deep currents.
• Identify the three factors that form deep
  currents.
• Investigate the relationship between currents
  and oceanic temperature differences.
• Explain how currents affect climate.
• Describe the effects of El Niño.

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Ocean Currents
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What is a current?

• A current is the movement of water that follows a
  regular pattern.
• Ocean water contains streamlike movements of
  water called ocean currents.
• There are two types of currents, surface currents
  and deep currents.

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Surface currents

• There are three causes of surface currents.
• Continental deflection
• Global winds
• Coriolis Effect

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What do you think continental deflection is?
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Continental deflection

• If the Earth was made up of only water, than the
  oceans would move in a uniform pattern.
• However the continents cause the currents to
  change directions when the current meets land.

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How do you think winds control currents?
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Global winds

• This is where the winds above the oceans surface
  push on the water causing it to move.

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What do you think the Coriolis Effect is?
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Coriolis effect

• The Coriolis effect is the apparent curving of
  the path of a moving object from an otherwise
  straight path due to the earths rotation.

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The Coriolis Effect
Visual Concept
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All three in action!

• When you combine all three factors they form the
  pattern of surface currents on Earth.

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Surface Currents, continued

• Taking Temperature Currents are also affected
  by the temperature of the water in which they
  form.
• The next slide shows Earths surface currents.
  Warm-water currents are shown as red arrows, and
  cold-water currents are shown as blue arrows.

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• Warm-water currents begin near the equator and
  carry warm water to other parts of the ocean.
• Cold-water currents begin closer to the poles and
  carry cool water to other parts of the ocean.

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Objectives for today!

• Describe surface currents.
• List the three factors that control surface
  currents.
• Describe deep currents.
• Identify the three factors that form deep
  currents.
• Investigate the relationship between currents
  and oceanic temperature differences.
• Explain how currents affect climate.
• Describe the effects of El Niño.

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Deep Currents

• Deep currents are the stream like movements of
  water far below the surface of the water.
• Density-the amount of matter in a given space
• Salinity- measure of the amount of dissolved
  solids or salts in a liquid.

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Deep Currents

• Deep currents are not controlled by wind.
• Deep currents form in parts of the ocean where
  water density increases. The density of the ocean
  is affected by temperature and salinity.

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Deep currents

• There are three ways to increase density of ocean
  water
• Decrease temperature
• Increase salinity through freezing
• Increase salinity through evaporation

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Decreasing Temperature
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Increasing Salinity through Freezing
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Increasing Salinity through evaporation
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Deep Currents, continued

• Formation and Movement of Deep Currents
  Differences in water density cause variations in
  the movement of deep currents.

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Objectives for today!

• Describe surface currents.
• List the three factors that control surface
  currents.
• Describe deep currents.
• Identify the three factors that form deep
  currents.
• Investigate the relationship between currents
  and oceanic temperature differences.
• Explain how currents affect climate.
• Describe the effects of El Niño.

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Ocean Atmosphere Circulation
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Equatorial to polar heat transport and water flow
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How do you think currents affect coastal
tempuratures?
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Surface Currents and Climate

• Warm-Water Currents and Climate Warm-water
  currents create warmer climates in coastal areas
  that would otherwise be much cooler.
• Why?

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Surface Currents and Climate, continued

• Cold-Water Currents and Climate Cold-water
  currents keep climates along a coast cooler than
  the inland climate year-round.
• Why?

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Surface Currents and Climate, continued

• Upwelling is the movement of deep, cold, and
  nutrient-rich water to the surface of the ocean.
• The nutrients that are brought to the surface
  support the growth of plankton. Plankton support
  larger organisms, such as fish and seabirds.
• Upwelling is shown on the next slide.

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Upwelling

• This brings nutrient rich waters up to the
  surface.
• Many organisms depend on these nutrient rich
  waters to survive.

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Surface Currents and Climate, continued

• El Niño is a change in the water temperature in
  the Pacific Ocean that produces a warm current.
• Effects of El Niño El Niño alters weather
  patterns enough to cause disasters, including
  flash floods, mudslides, and droughts. El Niño
  also prevents upwelling off the coast of South
  America.

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Surface Currents and Climate, continued

• Studying and Predicting El Niño Learning as
  much as possible about El Niño is important
  because of its effects on organisms and land.
• One way scientists use technology to predict an
  El Niño is with a network of buoys operated by
  the National Oceanic and Atmospheric
  Administration (NOAA).
• The buoys are located along the Earths equator
  record data about surface temperature, air
  temperature, currents, and winds.

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Objectives for today!

• Describe surface currents.
• List the three factors that control surface
  currents.
• Describe deep currents.
• Identify the three factors that form deep
  currents.
• Investigate the relationship between currents
  and oceanic temperature differences.
• Explain how currents affect climate.
• Describe the effects of El Niño.