1. Currents and Chemistry

2. Chemistry The oceans have high salinity: the total amount of dissolved salts in a liquid Sodium chloride (the same salt you put on your food) is in the oceans

3. Chemistry At the surface of the ocean, the salinity is less Why do you think that is? Due to melting ice and rain being added to the surface, there is more freshwater and less concentration of salt

4. Chemistry When water is salty, the water cannot freeze until it is -1.9 degrees Celsius The salt in the water INCREASES the density of ocean water Things float better in saltwater than in freshwater!

5. Chemistry As you go deeper in the water, the temperature…. DECREASES As you go deeper in the water, the pressure…. INCREASES As you go deeper in the water, the salinity…. INCREASES

6. Currents A current is a large stream of moving water that flows through the oceans Some currents move at the surface of the oceans while others move deep underwater

7. Surface Currents Surface currents are driven by winds They copy Earth’s major wind patterns The most powerful ocean current is the Gulf Stream

9. Coriolis Effect If the Earth were standing still, currents would always flow in straight lines The effect of Earth’s rotation on the direction of the winds (and therefore the ocean currents) is called the Coriolis Effect

10. Deep Currents Deep currents are caused by differences in the density of the ocean water Density of water depends on temperature and salinity When warm water moves north due to a surface current, it cools. When the water freezes, it leaves behind it’s salt, increasing the salinity of the water around it. This causes this surface water to sink. This sinking cold water is a deep current Deep currents move and mix water around the world!

11. Upwelling An upwelling is when winds blow away warm surface water and colder water rises to replace it Upwellings bring up tiny ocean organisms, minerals and other nutrients Without upwellings, surface waters would be very scarce in nutrients…therefore less life!

12. Finding Nemo