1. Chapter 13 Ocean Systems

2. Ocean water covers much of Earth 71% Earth covered by oceans 71% Earth covered by oceans All five oceans connected together All five oceans connected together Origins of oceans-Water separated from denser earth materials, water went to surface since least dense, water accumulated in lowest areas-formed oceans Origins of oceans-Water separated from denser earth materials, water went to surface since least dense, water accumulated in lowest areas-formed oceans

3. Ocean water contains salts, gases Ocean water contains salts, gases Ocean water contains salt, other dissolved solids, gases as in air Ocean water contains salt, other dissolved solids, gases as in air Salts Salts a. Salinity = amount of dissolved salt in seawater b. Average salinity = 35 g salt / 1000 g seawater (fill a glass with water, add 1 tsp. salt) c. Most salt = sodium chloride d. Natural processes add and remove salt from ocean, salinity constant for last 1.5 Billion yrs

4. Salts (cont.) Salts (cont.)  Density (salt water) > Density (fresh water) Greater salt concentration = greater density Greater salt concentration = greater density  Increase concentration by:  increase evaporation- shallow areas, warm climates  freeze water- salt left behind  Decrease concentration by:  dilute with fresh water- rivers enter ocean or lots of rainfall (tropics)

5. Gases Oceans contain gases - nitrogen, oxygen, and carbon dioxide Oceans contain gases - nitrogen, oxygen, and carbon dioxide Ocean animals take in oxygen, give off CO 2 -cellular respiration Ocean animals take in oxygen, give off CO 2 -cellular respiration Oxygen added by plants and algae-photosynthesis uses CO 2 + water Oxygen added by plants and algae-photosynthesis uses CO 2 + water CO 2 also used in animal shells CO 2 also used in animal shells

6. Salinity and density

7. The Dead Sea Located between Israel and Jordan Located between Israel and Jordan Lowest elevation on earths surface on dry land! (1,385ft. below sea level) Lowest elevation on earths surface on dry land! (1,385ft. below sea level) 33.7% salinity- 10 times more salty than ocean! 33.7% salinity- 10 times more salty than ocean! No animals or plants can live there! No animals or plants can live there!

9. Ocean Temperatures vary Ocean Temperatures vary Ocean water divided into three layers: 1. Surface layer- to 300 m, heated by the Sun, less dense layer 2. Thermocline - to 700 m, temp drops fast 24 to 4 C 3. Deep water – below 700 m, cold all year, around 0 o to 4 o C

10. Ocean temperatures

11. Ocean temperatures vary (con’t)  Temp at surface varies by location and season:  warm near equator, cold at poles  warmer in summer, colder in winter

12. Ocean Surface temperature

13. Information known primarily since 1950’s  Many mountains and deep canyons on ocean floor Ocean floor has many features Ocean floor has many features 1.Continental shelf- submerged land that extends from the shore to continental slope 2.Continental Slope- land that drops steeply at the edge of continental shelf

14. Ocean floor has many features (con’t) 3. Submarine Canyon- cut through continental shelf and slope 4. Abyssal plains = wide, flat area of ocean floor covered with sediment 5. Mid-ocean Ridges= the longest mountain ranges, run down the middle of oceans

15. Ocean floor has many features (con’t) 6. Seamounts- undersea volcanoes, and tall volcanoes, some that form volcanic islands 7. Volcanic Islands- underwater volcanoes tall enough to reach surface. 8. Ocean trenches- deepest section, over 11,000 m (6 mi) The deepest location on earth/ocean is called the Mariana Trench

18. Ocean Cross-section

19. Features of Ocean Floor

20. Ocean exploration Ocean exploration  Oceans largely unexplored-too much pressure, dark, no air, cold, expensive  Scuba equipment good for shallow, short dives, < 40 m (130 ft)  Small subs- dive to depths of 6500 m  Robots to go to bottom In 1960, scientist use a submarine like machine to dive down to the bottom of the southern part of the Mariana Trench (35,810ft.). That’s about a mile deeper than Mt. Everest is tall! Took 5hrs; equal to 16,000 tons of pressure pure cubic inch. The deepest point is actually 36,198 ft.

22. Mapping the ocean floor Mapping the ocean floor  sonar- mapping ocean floor using sound waves (echos) and measuring time, useful for small areas  Satellite imaging used for mapping large areas  Changes of surface caused by gravitational attraction of bottom shape

23. Types of Sonar

24. Satellite mapping

25. Oceans have major currents  Ocean current- a mass of moving water with similar temperature and salinity  Ocean currents distribute heat and nutrients around the globe

26. Global Surface Currents  Uneven heating at the Earth’s surface causes global winds (equator/pole)  Global winds produce surface currents in the oceans  Surface currents extend down 100-200 m (300-500 ft)  Earth’s rotation makes surface currents curve (Coriolis force)

27. Earth’s air circulation

28. Surface Currents

29. Global Surface Currents (Con’t)  Currents curve to the right, clockwise, in the Northern Hemisphere  Currents curve to the left, counter-clockwise, in the Southern Hemisphere  Shape of the continents also affect current flow

30. Global Surface Currents (Con’t)  Surface currents moderate global temperatures  carry warm water away from the equator  carry cold water away from the poles

31. Gulf Stream

32. Currents interact with climate  Moving air causes movement in water, water temperature changes the air above it  Surface currents move heat toward the poles and cool water from the poles toward the equator- moderating the temperature of any land they flow near  Gulf stream near Great Britain and Europe

33. Effect of Ocean Current

34. Currents interact with climate (Con’t)  El Nino is a change in the global winds which produces changes in the surface current in the Pacific which leads to changes in the upwelling off the western coast of South America which disrupts the weather around the planet for 12 to 18 months

35. Deep ocean currents  Deep currents are driven by density differences  Highest density sinks to bottom  Seawater becomes more dense by cooling, increasing in salinity, or both.  High density water formed at poles as sea ice forms  Water sinks to bottom and flows toward equator

36. Deep ocean currents (Con’t)  Water in deep currents involve two processes  downwelling- movement of water from the surface to greater depth, water is oxygen rich  upwelling- movement of water from the deep water to the surface, caused by shape of bottom upward, moves nutrient rich water to surface, providing food for fish

37. Upwelling

38. 13.3 Waves move through oceans Waves form in the open ocean 1. Moving air drags across the water’s surface and passes energy to the water 2. Other things that can cause waves a. Earthquakes b. Landslides c. Underwater volcanic eruptions

39. 13.3 Waves move through oceans Wave Action at the Water’s Surface 1. Parts of a wave A. Crest – the highest point of the wave B. Trough – The lowest point of the wave C. Wave height – The vertical distance between the top of the crest and bottom of the trough D. Wavelength – The distance between one wave crest and the next

40. 13.3 Waves move through oceans Wave Action at the Water’s Surface 2. Waves do not carry matter – They carry energy A. The water stays more or less in the same place B. As a wave passes by the water particle (matter) moves in a circular path

41. 13.3 Waves move through oceans Wave Action near Shore 1. Waves can travel for hundreds or thousands of Km before getting to shore 2. As a wave nears shore its trough slows down due to friction of it hitting ground 3. The crest continues at the same rate which eventually topples over causing the wave to break 4. As this water rushes back it can cause an undertow

42. 13.3 Waves move through oceans A. Waves cause currents near the shore 1.Longshore currents – is water which moves parallel to the shore 2.Occur in places where waves meet the land at an angle 3.Waves strike shore at an angle but water flows back straight down the beach 4.Moves sand and swimmers along the beach

43. Longshore Current

44. 13.3 Waves move through oceans A. Waves cause currents near the shore 5. Movement of sand and water by longshore currents builds up sand bars off shore 6. Waves build up behind sand bars and when they break through they produce an outward flow of water- a rip current 7. Rip currents flow at nearly right angles to the shore line. 8. Rip currents can be dangerous but can be escaped from by swimming parallel to shore

45. 13.4 Waters rise and fall in tides What causes tides What causes tides –The moons gravitational pull is the main driving force of tides The moons gravity causes our water to bulge on the side facing the moon The moons gravity causes our water to bulge on the side facing the moon Earth also gets pulled toward the moon which causes a bulge on the opposite side Earth also gets pulled toward the moon which causes a bulge on the opposite side –The sun’s gravity pulls too but not as hard so it is secondary seeing it is further away from us

46. 13.4 Waters rise and fall in tides Daily Tides Daily Tides –There are two high tides everyday and two low tides everyday High tides occur when the earth is facing the moon and directly away from the moon High tides occur when the earth is facing the moon and directly away from the moon Low tides occur 6 hours after the high tides Low tides occur 6 hours after the high tides –The further east you are the earlier the high and low tides hit –Tidal range is the difference in height between high and low tides

47. 13.4 Waters rise and fall in tides Moons phases Moons phases –It takes the moon 28 days to go around the Earth

48. 13.4 Waters rise and fall in tides Monthly Tides Monthly Tides –Caused by the sun, moon, and earth being in a line. –New Moon and Full Moon produce spring tides There is an extra high tidal bulge and extra low tidal dip There is an extra high tidal bulge and extra low tidal dip Larger then normal tidal range Larger then normal tidal range –During first and third quarter produces neap tides There is a smaller tidal bulge and smaller tidal dip There is a smaller tidal bulge and smaller tidal dip Smaller then normal tidal range Smaller then normal tidal range

49. 13.4 Waters rise and fall in tides Tidal Dams Tidal Dams –Built near the shore where tides come in –Water flows into the dam during high tides and gets trapped behind gates –When the tide drops the water is allowed to rush out of the gates spinning a turbine to created electricity