1. Composition and Movement of Ocean Water

2. Salinity Seawater is a solution containing a variety of salts dissolved in water Expressed in grams of salt per kilogram of water

3. Physical Properties of Sea Water Density(1.02g/ml – 1.03 g/ml) –What would increasing the amount of salt in the water do to the density? –Increasing the amount of salts, increases the density –What would happen to the density of the water if the temperature of the water increases? –Increasing the temperature decreases the density

5. Movement of Ocean Water Constant movement of ocean water is caused by wind and density differences Surface Currents Density Currents

6. What causes Surface Currents? Global wind systems Affect the upper 100 to 150 meters of water across the globe

8. Can you notice any pattern to the direction of the winds above and below the equator in each ocean basin?

9. Warm ocean currents such as the Gulf Stream Current in the North Atlantic, are important to global climate Warm ocean currents generally flow away from the Equator

10. Beginning in the Caribbean and ending in the northern North Atlantic, the Gulf Stream Current is one of the world's most intensely studied current systems. This extensive western boundary current plays an important role in the pole-ward transfer of heat and salt and serves to warm the European coastal regions. Gulf Stream Current

12. Gulf Stream at Present Time

13. Patterns to Surface Currents Cold ocean currents generally originate in polar regions and flow towards the Equator

15. Density Currents Aim: How does water not affected by surface winds circulate throughout the ocean basins?

16. An underwater current circles the globe with a force 16 times as strong as all the world's rivers combined This deep-water current is known as the global conveyor belt and is driven by density differences in the water. Water movements driven by differences in density are also known as thermohaline circulation

18. Density Currents Deep water circulation caused by differences in the densities of ocean water What might cause density differences in the ocean waters? –Temperature –Salinity

19. As a result of temperature: Dense cold water from Polar regions sinks and slides along the ocean floor toward Equatorial regions. The less dense water in the warmer regions are displaced

20. As a result of salinity changes: The Gibraltar Current Mediterranean Sea –Evaporation of sea water near the surface causes the surface water to have a higher salinity and therefore it becomes more dense –This water sinks and flows out of the sea and into the Atlantic Ocean –It is then replaced by water from the ocean.

21. Strait of Gibraltar

22. Lab Activity You will create and observe a model of a density current

23. Do you think ocean currents ever stop moving? What might cause ocean water to mix? What would happen to a stream of warm water that flows out into a colder body of water?