Switching Gears - Demonstration

1. Switching Gears - Demonstration

2. How Does Salinity affect Density in the Ocean?

3. What is Salinity? • The total concentration of all dissolved inorganic solids • Many salts dissolved in seawater • NaCl, KCl

4. Why is the Ocean Salty? • Weathering of rocks on land (carried by rivers into the ocean) • Waves and surf erode coastal rocks and ocean bottoms • Salt domes

5. How do you Measure Salinity? • Measured in parts per thousand (ppt) • Salinity is expressed by the amount of salt found in 1,000 grams of water. • Ex. 32ppt = 32 grams of salt in 1,000 grams of water *Hydrometer, refractometer

6. Ocean Salinity • Varies very little overall, but there is a great deal of variation due to location • Approx. 32ppt • Lower salinity • areas near rivers, areas with high amounts of rainfall • High salinity • areas with a lot of evaporation/lots of sun

7. How does the addition of salt affect water? • Raises the boiling point 216ºF instead of 212ºF • Decreases freezing temperature • Slows evaporation • Changes the density

9. Experiment • How does salinity affect density in the ocean? • Draw your observations • Describe in words what you observe • Answer the above question

10. How do fish adapt to changes in salinity?

11. Diffusion & Osmosis • Diffusion • the tendency for a liquid, gas, or solute to flow from an area of high concentration to an area of low concentration • Osmosis • diffusion of water through a semipermeable membrane

12. Osmoregulators • Organisms that have a regulation process that allows them to adjust the water concentration within their cells

13. Osmoconformers • Organisms that cannot control their internal water concentration • Their internal salinity rises and falls with the surrounding environment • Example: marine invertebrates

14. Descriptors • Euryhaline (“Eury” – wide, “haline” – salt) • Can tolerate significant fluctuations • Example: salmon & manatees • Stenohaline (“Steno” – narrow) • Cannot tolerate significant fluctuations • Example: goldfish & grouper

16. Video Clips • Dead Sea Dying • Bowling Ball

17. How does Temperature Affect Density in the ocean?

18. Experiment • What is the effect of temperature on density? • How does this relate to the ocean? • Draw your observations • Describe in words what you observe • Answer the above questions

19. What is the Effect of Temperature on Density? • Water becomes more dense as it cools • However, at about 4°C (right before the water freezes), water becomes less dense • Ice Floats

20. Ocean Water Density • Because temp and salinity affect water density, seawater stratifies (forms layers) • Thermocline: an abrupt change in temp leading to 2 distinct layers • Halocline: an abrupt change in salinity leading to 2 distinct layers • Pycnocline: Where density changes rapidly with depth.

22. Experiment: Layering Liquids Using what you have learned this week, can you use the 4 liquids to show stratified layers without mixing?

23. Key • Red:Hot and Salty • Blue: Cold and Salty • Yellow: Hot and Fresh • Green: Cold and Fresh

24. Conclusions: • Answer the questions given to you on a separate piece of paper in complete sentences!

26. National Geographic Article • Read the article individually • Answer the questions as a small group • Nutrients in the Ocean: • Phosphate, Nitrate, Silica, Iron…things typically dissolved in the ocean that plants and animals need to survive

27. Describe the importance of the ocean circulation pattern in the Southern Hemisphere. • How do differences in ocean water density make the circulation pattern possible? • According to the article, which has a greater impact on density in the ocean, salinity or temperature? Suggest a possible reason for this. • Define Biological Productivity • How might global warming affect the conveyor belt?

30. Warm-Up • It is a scientific fact that the Earth heats unevenly. • What evidence can you give to support this idea? • What factors do you think cause the Earth to heat unevenly?

31. Evidence? • Seasons! • If the sun were to heat the Earth evenly, there would be very little change in temperature over the course of the year.

32. 4 Factors that Cause the Earth to Heat Unevenly: • Earth is spherical (light from a single source won’t strike a sphere evenly) • Earth’s axis of rotation is tilted 23.5 degrees • Distance between Earth and sun varies with time of year • Earth’s orbit isn’t circular, it’s slightly elliptical (more heat when closer to sun)

33. Video Clip • As you watch the 6 minute clip, answer the following question: • How does the ocean influence weather and climate?

34. How is the ocean a driving force for weather and climate? • The ocean stores more heat than the atmosphere • el Niño and la Niña • Changes in water temp affect humidity in the air which steers storms in certain directions • Warm water from the Gulf is carried in the Gulf stream causing areas in Europe to be warmer • Hurricanes

35. Map Activity • Accurately draw and label the Equator, Tropic of Cancer and Tropic of Capricorn on your map.

36. Directions Cont’d • In pencil, draw and label the 7 major ocean currents indicating direction of the current • West Wind Drift (a.k.a. the Antarctic Circumpolar Current) • East Wind Drift (Antarctic Coastal Current/Antarctic Subpolar current) • North Equatorial Current • South Equatorial Current • Peru Current • Kuroshio Current • Gulf Stream

37. Directions Cont’d • Using a hot color and a cold color, indicate on the map (by tracing over your pencil lines) whether each current is a warm water current, cold water current, or contains both

38. Currents of the World

39. What is a current? • The “motion of the ocean” • A steady flow of water within a larger body of water • Surface currents and deep currents

40. Why are Currents Important? • Moderate climates • Mix nutrients and add oxygen • Transportation (larvae, nekton, boats, etc.)

41. Based on Your Map: How Do Ocean Currents Differ? • Direction of flow • Relative Temperature • Velocity

42. Demonstration • Surface Currents • Materials • Plate • 400mL of Water • Cinnamon • Sand • Straw

43. How do the following 3 Factors Drive Ocean Currents? • 1. The rise and fall of the tides • 2. Wind • 3. Thermohaline circulation

44. 1. The rise and fall of the tides • Tides create a current (called “tidal currents”) in the oceans, near the shore, and in bays and estuaries along the coast. • They are the only type of currents that change in a very regular pattern and can be predicted for future dates.

45. 2. Wind • Winds drive currents that are at or near the ocean's surface. • Measured in meters per second or in knots • 1 knot = 1.85 kilometers per hour or 1.15 miles per hour • Locally - winds drive currents near coastal areas • Globally – winds drive currents across the open ocean

46. 3. Thermohaline Circulation (aka Global Ocean Conveyor Belt) • A process driven by differences in water density due to temperature (thermo) and salinity (haline) variations in different parts of the ocean. • Can be deep or shallow • Move much slower than tidal or surface currents.

47. Video Clip • Surfing Scientist Live Demonstration

49. What can 28,000 rubber duckies lost at sea teach us about our oceans?