Understanding Ocean Water Salinity

1. Warmup 10/9/12 Which type of traditional energy source do you think is best? Why? Give at least 3 reasons.

2. Ocean Water

3. Ocean Water: SalinityObjectives Students will be able to describe the composition of seawater Students will be able to analyze changes in salinity

4. Ocean Water: Salinity - Key Points • Salinity is the amount of dissolved substances/ salts in the oceans • It is expressed in ‰, parts per thousand • Salinity, temperature, and density vary within the ocean • Salinity and temperature affect the density of water • Increased salinity and decreased temperature result in more dense water

5. Ocean Water: Salinity • Salinity is the amount of dissolved solid material in water (more commonly thought of as salt) • The most common salt in seawater is sodium chloride • Because the proportion of the dissolved substances is such a small number, oceanographers express salinity in parts per thousand, ‰ • Where do you think these salts come from?

6. Ocean Water: Salinity • The main source of these salts in seawater is chemical weathering of rocks on the continents • They reach the ocean through runoff • The other major source is the earth’s interior

7. Ocean Water: Salinity • The salinity of ocean water varies slightly around the world • What can differences in salinity do? • In general, when the amount of water in the oceans changes, the salinity changes • Anything that increases the amount of water will decrease salinity (make the water more dilute) • Anything that decreases the amount of water will increase salinity • Brainstorm: what are some processes that could increase the water in oceans? Decrease the amount of water?

8. Ocean Water: Temperature, Density, and Zones of Life November 17, 2010

9. Objectives Salinity and temperature affect the density of water Increased salinity and decreased temperature result in more dense water Scientists divide the ocean into zones of marine life based on sunlight, distance from the shore, and depth of the water

10. Ocean Water: Salinity • Salinity and Density • Recap: What is density? What is its formula? • The two main factors that affect density are salinity and temperature • The higher the salinity, the more dense the water

11. Ocean Water: Temperature and Density • Just like salinity, the temperature of the ocean varies • At the surface of the ocean, temperature differences are mostly due to the amount of energy received from the sun • This means: • Areas at lower latitudes (closer to the equator) receive more direct, and intense sunlight and are therefore warmer

12. Ocean Water: Temperature and Density • Temperature varies with depth • In most places, the water temperature decreases as you go deeper (this isn’t as true near the poles) • Temperature does not decrease evenly • Thermocline: area of rapid change in temperature (thermo= heat, cline = slope) • Important because it creates a vertical barrier between types of marine life

13. Ocean Water: Temperature and Density two main factors that affect density are salinity and temperature Warmer water is less dense and will rise Colder water is more dense and will sink

14. Ocean Water: Temperature and Density Ocean water is layered based on differences in density Surface/mixed zone Transition zone Deep zone

15. Ocean Water: Temperature and Density • Surface zone • Water is the warmest because it is heated by the sun • Water is mixed by waves, currents, and tides • Temperature is fairly uniform • Only about 2% of the ocean

16. Ocean Water: Temperature and Density • Transition zone • Temperature decreases quickly with depth • Thermocline • About 18% of the ocean water • Deep zone • Sunlight never reaches this zone • Temperatures are very cold (only a few degrees above freezing) • 80% of the ocean water

17. Warmup In which of the three zones of the ocean would you expect to find the lowest density sea water? Why? • Would you expect the lowest density to float or sink? • What factors determine the density of sea water? • How are these factors related to the three zones?

18. Warmup What is the layer of rapid temperature change with depth called? What factors affect the density of seawater? How do these two factors affect the density? Where is most ocean water located? Describe this zone.

19. Ocean Movement

20. Objectives TODAY, I WILL BE ABLE TO: Identify the affects of waves on the shoreline. Describe how wind affects ocean water movement. Identify patterns of ocean currents.

21. Types of Water Movement • There are three general types of ocean water movement: • Waves • Surface currents • Deep-Ocean currents • Each plays a different role in the movement of water in the oceans.

22. Waves When you go to the beach, what is one of the first things that you notice? WIND! It’s always windy by the ocean! Did you know that… Ocean waves are caused by WIND! Let’s take a closer look. A wave is visible evidence of energy passing through water. There is no better use of a wave than to SURF!

23. Surface Currents • Surface currents are movements of water that flow horizontally on the surface of the ocean. • Like with waves, the energy that drives surface ocean currents comes from wind. • Friction is also involved in the development of surface currents. • Remember the video from earlier? The same concept applies.

24. Surface Currents Map What do you notice about the current pattern in the northern hemisphere? What do you notice about the current pattern in the southern hemisphere?

25. Surface Currents Because of the earth’s rotation, currents are deflected to the RIGHT in the Northern Hemisphere and to the LEFT in the Southern Hemisphere. This is known as the Coriolis effect. BOTTOM LINE: The Coriolis effect causes surface ocean currents to be deflected.

26. Surface Currents Wind can also cause vertical water movements. Upwelling is the rising of cold water from deeper layers to replace warmer surface water.

27. Surface Currents • Upwelling brings greater concentrations of dissolved nutrients, such as nitrates and phosphates, to the ocean surface. • The importance of upwelling.

28. Deep Ocean Currents In which direction do the warm currents flow? What about the cold currents?

29. Deep-Ocean Currents • Ocean currents that move toward the poles are warm. • An ocean current that is moving toward the equator is cold. • Video showing ocean currents. • Why is the water moving towards the equator cold? Where does it become cold? • It becomes cold when the current moves deeper under the water. Colder water is denser. • What about the warm water? • It warms up when the current brings it up to the surface. This happens around the equator because of exposure to sun.

30. Check In – Use complete sentences What is the visible evidence of energy passing through water? Where does the energy come from that drives surface ocean currents? Which FORCE is involved in the development of surface currents? What temperature are the currents that move towards the poles? What about the currents that move towards the equator? What causes surface ocean currents to be deflected?

31. Putting it all together Take a look at how salinity, density and temperature affect the ocean currents. Here!

32. You be the expert! I will assign each of you a team number. On the back of your notes, write your team number in the designated spot. Now, look at your team number and write down what YOU are going to be the expert on today…

33. You be the expert Coriolis Effect Upwelling Waves Shoreline abrasion Shoreline protection Cape Hatteras Deep-Ocean Currents

34. You be the expert First, read on your own in your books about your subject area. Coriolis Effect – pg. 449 Upwelling – pg. 450-451 Waves – pg. 455-456 Shoreline abrasion – pg. 463-464 Shoreline protection – pg. 466-467 Cape Hatteras – pg. ES 32 Deep-Ocean Currents – pg. 451-453 As you read, write down at least 5 key points. If you have time, draw a simple diagram of your subject area in the space provided.

35. You be the expert When I tell you to, with your groups determine the 5 MOST IMPORTANT key points. Write them down. This will be turned in to the teacher when time has expired to share with the class.

36. You be the expert As I read about each subject, each of you is required to write down ONE thing about each subject that you feel is most important.

37. Coastal Climates Specific heat capacity is amount of heat required to change a substances temperature by 1`C. Water has a higher specific heat capacity than air. (Water is more resistant to changing temperature.) The temperatures we experience are due to the amount of heating of the atmosphere above us and the ground and water around us.

38. Coastal Climates Land heats and cools more rapidly than water Land also reaches higher and lower temperatures than water The temperature of the land and water influences the temperature of the air above it This explains why inland areas experience greater temperature variations than cities near large bodies of water.

39. Exit Ticket • Name one thing that decreases beach erosion without the construction of protective structures. • Ocean currents that move toward the poles are: • warm b. cold c. the same temperature d. pretty • What causes surface ocean currents to be deflected? a. Deep currents b. the Coriolis effect c. The earth’s rotation d. global winds

40. Warm Up What causes ocean currents to be deflected? What temperature is an ocean current that is moving towards the equator? Which force is involved in the development of surface currents?