1. June 2011
Ocean Currents
Ocean water circulates in __________ caused by _____ and by _________ differences
Currents are the _____ of __________between areas of different surface _________or different _______________
Ocean Currents

2. Ocean Currents
Ocean water moves constantly sideways, up, down because it is:
Blown by __________
Moved by differences in __________ below the surface zone
__________ unevenly

3. Ocean Currents
Ocean water moves constantly sideways, up, down because it is:
Affected by Earth’s __________ (Coriolis)
Pulled by sun & moon (_______)

4. Currents Important because they Moderate ____________________
Mix ____________ & ________________
Transport ____________ & ____________

5. Coriolis Effect Causes currents to move
_____________ in Northern Hemisphere
_____________ in the Southern Hemisphere

6. Surface currents affect the uppermost ________ of the ocean
Some surface currents are rapid and __________, with well-defined boundaries

7. Others are slow and _______
Largest currents organized into huge circuits called __________

8. Gyres - ________________________________________________

9. _________________ boundary currents are located on the __________________ side of the OCEAN - not the continent.
_________________ boundary currents are located on the _________________ side of oceans.

10. Comparison of Boundary Currents
Western
Eastern
currents bring __________ water from the equator
1. currents bring ____________ water from the poles
2. __________salinity;
__________oxygen content
2. __________ salinity;
__________high oxygen content
3. nutrient __________,
__________ upwelling
3. nutrient _____________due to ____________
4. __________ biomass
4. __________ biomass

12. Effect of Surface Currents on Climate
Surface currents ________ heat worldwide
Warm water flows to _______ ________
____________ heat to the air and cools
Moves back to __________ latitudes
Absorbs __________
Repeats

13. Upwelling/Downwelling
Upwelling and downwelling describe the ____________ movement of water

14. Upwelling __________ movement of water
____________ ___________ - due to divergence of surface currents
____________ ____________ - caused by wind blowing parallel to shore or offshore
Brings ______________

16. Downwelling __________ movement of water Caused by
___________ in surface water density
Wind blowing parallel to shore or onshore (__________ __________)
Brings dissolved ________ & _________ to deeper water

18. NORMAL
Normally, trade winds blow warm surface water toward the _________Pacific.
When the ________ _________falter, ___________water piles up in the western Pacific about 1 & ½ feet higher than the average ocean surface.

19. NORMAL
This causes the ______________ to rise near the surface in the eastern Pacific.
__________, nutrient-rich water wells up from the thermocline to the ______ waters off the coast of Peru
- good for fishing.

20. EL NIÑO
El Niño describes _____________ oceanic and atmospheric conditions.
First noticed off the coast of Peru around Christmas time, the condition was called El Niño referring to the Christ child.

21. El Niño’s ____________trade winds blow warm water ____________, across the equatorial region of the Pacific.
This __________the thermocline across the Pacific, and stops ________________.
Because warm water evaporates __________, the air fills with more water vapor and it produces more _________.
NOAA
El Niño occurs primarily in the __________ Pacific Ocean but it affects __________ __________.

22. La Niña
When too much westerly wind blows surface water near the _______________, it has an effect on the weather that is often _____________to El Niño, called La Niña.
NOAA

23. Comparison of El Niño and La Niña
____________ocean temperatures
____________ ocean temperatures
occurs every ________ years
frequency __________
__________ than normal summers
__________ than normal summers
__________ trade winds
__________ trade winds
___________________ hurricanes forming in N. Atlantic

24. DENSITY DRIVEN CURRENTS
AKA THERMOHALINE CURRENTS
____________ refers to temperature and ____________ refers to salinity
Cold water sinks at the __________ and crawls toward the rising warmer water at the ____________________

25. Density Structure of the Ocean
_______________ weighs 2-3% more than pure water
Cold, salty water is more _____ than warm, less salty water
Much of the ocean can be divided into ______ __________ zones:
surface, pycnocline & deep

26. Density Zones __________ or Mixed Zone
Temperature, salinity & density ____________________ due to currents and waves
In contact with _____________
Exposed to _____________
Least __________ water
2% all of ocean water
~150 meters deep

27. Density Zones _____________ aka Thermocline aka Halocline
Density ____________ with depth, temperature ____________, salinity ______________
Isolates __________ water from denser layer below
18% of all ocean water

28. Density Zones _____________ Zone Below pycnocline Depth below 1000 m
Little __________ with depth
Very cold (1-3C) and _______
80% of all ocean water

29. Density stratificaiton in the ocean

30. Density Stratification & Water Movement
Water mass – body of water with same temperature and salinity
Even deepest water originates at ______________

31. Density Stratification & Water Movement
Dense water masses form:
near _________ (as water freezes)
in __________ areas (where water evaporates)

32. Density Stratification & Water Movement
Water masses below pycnocline do not mix – ________________ – too cold

33. Thermohaline Circulation
Circulation of 90% of ocean water below surface zone is ________ driven
Dense water _____, less dense _____
Movement called – __________ __________
Can take 100’s of years to circulate

34. Water masses almost always form at ocean __________
Densest and deepest form by surface conditions that caused the water to become very cold and salty at the ____________

35. The Global Heat Connection
Because they transfer large quantities of heat, ocean currents affect world ________ and __________
The transport of _______ water to the _______ regions is part of the global conveyor belt for heat ________

36. Ocean Flow The slow, steady flow of water
distributes dissolved ________ and ________
mixes __________
transports __________ marine organisms among ocean basins