1. Ocean Movements
EES Unit 4.2

2. Three Ways the Ocean Moves
Waves
Tides
Currents

3. Waves Waves form because of the wind When wind is very strong
When wind blows for a long time
When wind blows over a long distance

4. Waves are a transfer of energy
Energy from molecule to molecule
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Water molecules stay in place and rotate
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5. Individual water molecules stay in place and rotate

6. Near the shore
Waves break because they get too large for their base to support
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Large waves caused by earthquakes are called tsunami
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7. Tides
Daily tides
The daily rise and fall of sea level is called a tide
Tides are caused by:
Gravity pull from the moon (primary reason)
Moon has greater effect because it is closer than the Sun
Gravity pull from the Sun (secondary reason)

9. Remember: this area between high and low tide is also called the intertidal zone

10. High tides
Moon pulls water on closest side
Moon also pulls the Earth, leaving water on the other side behind
Difference between high and low tide is called tidal range
Low tides
On opposite sides of Earth from where high tides occur
t-causes-the-tides.html

11. Monthly tides
Spring tides
Whenever the moon is in its full or new moon phase
Tides will be higher than normal
Neap tides
When the moon, Earth, and Sun are 90 degrees to one another
Tides are at their lowest
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ides1.htm

12. Spring tides
When Earth, moon, and Sun are in line with one another (during new and full moon)

13. Neap tides
When Earth, moon, and Sun are at 90 degree angles (first or last quarter)

14. Ocean Currents Surface currents Caused by: Global wind patterns
Rotation of the Earth
The Coriolis effect
Equator receives more heat than poles
Heat travels north and south from the equator
Wind + Rotation = Coriolis effect
Causes currents to move toward the right in the Northern Hemisphere and left in the Southern Hemisphere
NOTE: Study the diagram of the Coriolis effect to understand it

15. The Coriolis Effect

16.
Shape of ocean basins
Can travel thousands of miles and reach down hundreds of feet
Local surface currents
Longshore currents
Caused by the wind not blowing exactly straight in to shore
Rip currents
Carry water from shore out to sea
Very dangerous – if caught in one, swim parallel to shore until free
Effects on climate
Can raise temperatures of colder areas by as much as 30°F

17. The shape of the major ocean basins has a big effect on the direction that currents move.

18. The major gyres in the world’s oceans

19. Gulf Stream Current is what keeps water in the Carolinas warmer throughout the year

20. Deep ocean (thermohaline) currents
Thermo = temperature
Haline = salinity
Deep ocean water movement is driven by temperature and salinity
Happens at the surface
Equator = warmer while poles = colder
Cold, dense water sinks in certain places
At the north pole and Antarctica
This is called downwelling

21. Thermo = temperature
Haline = salt

22. Cold, dense water moves along the ocean bottom
Water must rise in other places
This is called upwelling
Usually happens along coastlines
Upwelling brings nutrients and ocean life to the surface
GREAT fishing areas

23. Upwelling: when wind pushes water away while deeper, colder water takes its place

24. Areas of major upwelling on Earth
These areas have huge biodiversity because of nutrients coming up from deep in the ocean