1. Ocean Currents Beth Roland Jacobs Fork Middle School Team 5 Mountaineers

2. Current Influences Currents are influenced by: Weather-Global Wind Belts Earth’s Rotation- Coriolis Effect Position of the Continents

3. Surface Currents Surface currents are the horizontal movement at or near the ocean’s surface. Can reach a depth of 100’s of meters and lengths of 1,000’s of kilometers allowing them to travel across oceans Surface Currents are controlled by: Global winds Travel East to West at Equator Travel West to East at Poles W N E S

4. Surface Currents Coriolis Effect- curves or deflects the path of global winds –Example: rolling a ball over a spinning disk will curve the line of travel N. Hemisphere- turn clockwise and in the S. Hemisphere- turn counterclockwise Continental Deflections- when surface currents meet continents they are deflected and the direction is changed.

5. Global Surface Currents

6. Current Characteristics Temperature- Warm water currents continuously collide with cold water currents allowing for water turn over. Warm water rises and cold water sinks. Salinity- Water with a greater percentage of salt (sodium chloride) is denser and will sink when mixed with water with less salt.

7. Deep Currents Deep currents occur within our oceans and are not controlled by global winds but by density Higher temperatures and Lower salinity= decreased density Lower temperatures and higher salinity= increased density

8. Density Impact on Water Movement A. Decreasing Temperature Cold, arctic air decrease heat energy and therefore temperatures at the surface decrease. Water becomes more dense and sinks and travels towards the equator.

9. Increasing Salinity via Freezing Ice floats as it is less dense than the liquid water and the dissolved solids are not frozen and add salinity to the liquid water beneath the ice. Higher salinity = higher density and the water sinks.

10. Increasing salinity via evaporation In warm climates, water molecules at the surface evaporate leaving behind dissolved solids which increases salinity. Denser water sinks.