1. Ocean Currents

2. Mass movement or flow of ocean water River within the ocean Two types
Ocean Currents
Mass movement or flow of ocean water
River within the ocean
Two types
Surface and Deep

4. Currents Due to the Earth’s Rotation
Northern - Circle clockwise
Southern - Circle counterclockwise
Warm Water - Flow away from the equator
Cold Water - Flow towards the equator
Western - Have warm water (Gulf Stream)
Eastern - Have cold water (California)

5. Surface Currents:
Horizontal, stream-like movements of water that occur at or near the surface of the ocean
Can reach depths of several hundred meters

6. Surface Currents
Controlled by three factors
Global winds
Coriolis Effect
Continental Deflections

7. Cause surface currents to flow in the direction the wind is blowing
Global Winds
Cause surface currents to flow in the direction the wind is blowing
Winds Driving Currents
Trade Winds - Push equatorial currents westward
Westerly Winds - Push polar currents eastward
Winds Near India - Reverse directions between summer and winter producing monsoons

8. Coriolis Effect
The apparent curving of moving objects due to the Earth’s rotation
Northern Hemisphere = clockwise
Southern Hemisphere = counter clockwise
Continental Deflections
Shape of continents change the direction of current flow

9. Deep Currents
Stream like movement of ocean water far below the surface
Caused by changes in density
Change in temperature
Change in salinity

11. Change in temperature
Decreasing the temperature of water increases density
Change in salinity
Increasing the salinity of water increases density

12. Surface currents and climate
Warm water currents
On the east coasts of continents
Bring warm water to colder regions

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

15. Cold Currents Flow on the east shore towards the equator
Canary
California
Benguela
Peru (Humboldt)
Flow out of the far north
Labrador
Greenland
Kamchatka (Oyashio)

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

19. Upwelling
Wind and Earth’s rotation push surface water away from the west coast
Cold, deep water rises to replace the displaced surface water
At 60ºS in the Antarctic upwelling occurs
Wind belts diverge pushing surface water
Dense Antarctic Bottom & Intermediate waters sink
North Atlantic Deep water rises bringing nutrients for phytoplankton to thrive
Fish feed on phytoplankton – commercial fishing good

21. Causes of warm and cold currents
El Niño
Change in the water temperature in the Pacific Ocean that produces a warm current

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

24. Density Currents
Turbidity - Water mixes with sand, silt, clay to become more dense
Evaporation - Water evaporates leaving saltier more dense water in warm, dry climates
Cooling - Water contracts becoming more dense in polar regions
Freezing - Water freezes leaving saltier more dense water in polar regions

26. What is a surface current and what causes them?
Question 1
What is a surface current and what causes them?

27. They are powered by wind
Answer
Surface currents move water horizontally – parallel to the Earth’s surface
They are powered by wind

28. What is the Coriolis Effect?
Question 2
What is the Coriolis Effect?

29. Answer
The Coriolis effect is the shifting of winds and surface currents caused by Earth’s rotation.

30. Question 3
What is upwelling?

31. Answer
Upwelling is a vertical circulation in the ocean that brings deep, cold water to the ocean surface.