1. Motion in the Ocean

2. Ocean Currents
Warm currents flow AWAY from the equator and towards the poles
Cold currents flow TOWARDS the equator from the poles

3. Why is Ocean Circulation Important?
It transports heat from the equator to the poles
It transports nutrients and organisms – it returns oxygen to the system and stirs up food from bottom
It influences weather and climate
It influences commerce

4. What are Currents?
Ocean currents are rivers of circulating waters found in the ocean
There are two types:
Surface Currents- the upper 400m of the ocean (10%)
Deep Water Currents- Thermal/Salinity currents (90%)

5. Surface Ocean Currents
Make up 10% of the oceans’ waters
Up to a maximum depth of 400 meters
Broad, slow drifts that NEVER cross the equator
Mostly wind generated
Create gyres- enormous circular currents

6. Importance of Surface Currents
Migration
Navigation
Weather

7. Deep Ocean Currents Makes up about 90% of the oceans’ water
Differences in density are related to salinity and temperature which causes the waters to move up or down beneath the ocean

8. Thermohaline Circulation
Global ocean circulation that is driven by differences in densities of the sea water which is controlled by:
Temperature
Salinity (salt)

9. Importance of Deep Ocean Currents
Upwelling
Movement of deep water to surface
Hoists cold, nutrient-rich water to surface
Produces high productivities and abundant marine life

10. Factors Influencing Currents
The Wind
Just as wind moves from high pressure to low pressure, so do our waters
Winds blow across the surface creating friction and motion
The water piles up because the water currents flow slower than the winds

11. Factors Influencing Currents
The Sun
heats the water making it less dense and creating a convection current in the ocean
Factor also referred to as water density

12. Factors Influencing Currents
Water’s Salinity-
Salinity means salt content
Saltwater is more dense, so it sinks lower than fresh water

13. Factors Influencing Currents
The Coriolis Effect
Causes water to move right in the Northern Hemisphere (clockwise)
Causes water to move left in the Southern Hemisphere
(counter-clockwise)

14. Reflective Questions? 1. How are ocean currents produced?
2. Where do cold currents come from? Where do warm currents come from?
3. How do ocean’s impact climate?