1. Currents Where are the Oceans? Identify the Oceans Tides Waves
The Ocean Floor
Ocean Storms

2. Where are the Oceans?

3. Ocean Currents

4. What percent of the earth’s surface is covered in water? ______________
What percent is land? ___________

5. What percent of the earth’s water is salt. What percent is fresh
What percent of the earth’s water is salt? What percent is fresh? Drop in the Bucket

6. World Ocean Facts Area (1,000,000 km²) Volume (1,000,000 km³)
Average Depth (m)
Maximum Depth (m)
Atlantic Ocean
82.4
323.6
3926
9200
Pacific Ocean
165.2
707.6
4282
11,022
Indian Ocean
73.4
291.0
3963
7460
Arctic Ocean
14.1
17.0
1205
4300

7. Currents

8. There are two principle ways to measure currents:
Eulerian method employs current meters fixed to the sea bottom.
Two Impeller Meters

9. Langrangian method employs drifters, drogues, or floats that are set loose at the sea surface or at predetermined depths and tracked acoustically.
The Lagrangian Method

10. Ben Franklin and the Gulf Stream
In the 1750s when Postmaster for the American Colonies, Ben Franklin and Capt. Timothy Folger created the first map of the Gulf Stream to help speed up delivery of mail to and from GB

11. Types of currents:
Wind-driven currents (surface currents) occur in the uppermost 100 m or less
Density currents (vertical currents) caused by salinity and temperature produce very slow flows in deeper waters.

12. Surface Currents
Wind blowing over the ocean can move it due to frictional drag.
Waves create necessary roughness for wind to couple with water.
One “rule of thumb” holds that wind blowing for 12 hrs at 100 cm per sec will produce a 2 cm per sec current (about 2-3% of the wind speed)

13. Top-down drag Wind acts only on the surface water layer.
This layer will also drag the underlying water, but with less force.
Consequently, there is a diminution of speed downward.
Direction of movement is also influenced by the Coriolis Effect and Ekman Spiral

14. Coriolis Effect
The French scientist, Gaspard Coriolis, first explained the deflection of objects moving over the surface due to Earth’s rotation.
coriolis experiment
Pete Bethune Whale Wars (26 min)

15.                                                                                                                  
Ekman Spiral
Nansen and others exploring the Arctic noticed that ice and surface currents move at an angle to the wind direction. Ekman first explained the mathematics of this phenomena, and why it decreases with depth to produce the spiral pattern.

16. Vertical Ocean Currents
Driven by temperature and salinity differences
as water reaches the poles, it cools resulting in evaporation or freezing, leaving remaining water saltier and more dense. In addition, cold water is denser than warm water, causing it to sink (thermohaline circulation).

17. The Great Ocean Conveyer
Why is this important?
VIDEO

18. WHY ARE THESE CURRENTS IMPORTANT??
General Surface Current Patterns
Temperature Distribution
Shape coastlines
Oxygen / Carbon Dioxide Exchange
Distribution of Nutrients (Upwelling and Downwelling)
Pollution Dispersal
Plastic Plague Video
WHY ARE THESE CURRENTS IMPORTANT??

19. Gyres Circular surface currents patterns
Prevailing Westerlies and Trade Winds strongly influence these flows
Clockwise rotation in the Northern Hemisphere, counterclockwise in the Southern

20. Upwelling
Large amounts of nutrient rich water moves up to the surface from the below
Occurs most frequently in areas that experience monsoons and steady winds
upwelling demo
seamounts

21. Research 1 ocean current!
Choose 1 of the ocean currents
Is this a warm or cold ocean current?
Name and provide a picture for one ocean organism that relies on the movement of that current
Describe why this current is important for that organism’s survival (diet, migratory patterns, etc) Be descriptive! 6-7 sentences
Provide a map of the location you are describing and describe the pattern of its movement

22. Create an ocean mural
Use the internet to find 3 fish (from 3 of the 5 ocean zones) Epipelagic, mesopelagic, bathypelagic, abyssopelagic, hadopelagic
Cut and paste a picture of each fish as well as its common name and adaptation for survival in its zone!
Print out, color, cut and add to the mural!
TUNA(epipelagic) – Countershaded color to camouflage with sunlight in order to hide from predators/ stalk prey

23. Review Questions
What are 3 properties of ocean water that vary in different parts of the ocean?
temperature, salinity, pressure, gases, density
How does the direction of ocean currents differ north and south of the equator?
north-clockwise, south-counterclockwise
What current does the Gulf stream form as it travels north?
North Atlantic Drift