1. Chapter 1 The Growth of Oceanography ©2003 Jones and Bartlett Publishers

2. There is a basic difference between the terms oceanography and oceanology. Oceanography is the recording and description of the physical, chemical and biological characteristics of the ocean. –This term inadequately describes modern scientific ocean investigations. Oceanology is the scientific study of the sea by applying traditional sciences, such as physics, chemistry, mathematics, etc., to all aspects of the ocean. Oceanography: What is it?1-1

3. There are three major stages in the history of ocean research 1-2 Historical Review of Oceanography Ocean exploration was the period when people explored the ocean boundaries. –Notable explorers include: The Phoenicians, Phytheas, The Polynesians, Herodotus, the Vikings, Bartholomew Diaz, Vasco de Gama, Ferdinand Magellan and Sebastian del Cano. Early scientific investigations began when people began to describe the ocean. –Notable scientists include: James Cook, Matthew, Fountaine Maury, Charles Darwin, C. Wyville Thomson, and Fridjof Nansen. Modern oceanography or oceanology. - Application of modern scientific methods to study of ocean systems.

4. The Circumglobal Voyage of Magellan 1519 - 1522

5. The Voyage of The Beagle (Darwin) 1831 - 1836

6. The Challenger Expedition 1872 - 1876

7. Drift Route of the Fram 1893 - 1896

8. Fridtjof Nansen

10. Fridtjof Nansen’s “Farthest North”

11. 1-2 Historical Review of Oceanography As is true in most sciences… The history of scientific achievements in oceanography is punctuated by advances in sampling technology.

12. 1-2 Historical Review of Oceanography Then… Deploying Nansen bottle, RV Atlantis, Ca. 1920’s

13. 1-2 Historical Review of Oceanography …and now CTD-rosette system to measure temperature, Salinity, oxygen, etc. continuously.

14. 1-2 Historical Review of Oceanography Deploying CTD-rosette aboard RV Townsend Cromwell, Hawaii, 2001 …and now

15. 1-2 Historical Review of Oceanography

16. 1-2 Historical Review of Oceanography Then… Beebe’s bathysphere, Ca. 1930

17. 1-2 Historical Review of Oceanography …and now. WHOI’s Alvin

18. 1-2 Historical Review of Oceanography Discovery of deep-sea hydrothermal vents and ecosystem separate from surface of Earth

19. 1-2 Historical Review of Oceanography Studying hydrothermal vent communities may help us understand if life is possible on other planets.

20. 1-2 Historical Review of Oceanography

21. 1-2 Historical Review of Oceanography Hawaii Maui

22. 1-2 Historical Review of Oceanography

23. 1-2 Historical Review of Oceanography

24. 1-2 Historical Review of Oceanography Surface Drifters

25. Current and future oceanographic research include: More international efforts because of cost and scale of research. Greater use of submersibles for deep ocean exploration. Increased use of computers for modeling complex ocean processes. Use of remote sensing and other in-situ instruments. 1-3 Current and Future Oceanographic Research

26. The Scientific Method Scientific Hypothesis: a tentative, explanatory, interpretative generalization about natural phenomena. Hypotheses are derived by inductive reasoning. Reason from the specific and known to the general and unknown. Arise from observation. Tentativeness requires they be verified by experimentation. Cannot be supported by logic alone. 1-4

27. The Process of Science

28. Graphical Representations

29. Typical ‘x-y’ graphOceanographic profile graph

30. Graphical Representations LINEARLOGARITHMIC

31. Graphical Representations Anatomy Of a graph

32. Graphical Representations Axes titles

33. Graphical Representations Units

34. Graphical Representations Scales

35. Chapter 2 The Planet Oceanus ©2003 Jones and Bartlett Publishers

36. 2-1The Earth’s Structure Earth consists of a series of concentric layers or spheres which differ in chemistry and physical properties. Earth’s structure can be described in terms of layers with different compositions or different physical properties.

37. 2-1The Earth’s Compositional Structure Crust -surf to ~ 50 km -low-density rock -silicon, aluminum & oxygen -oceanic & continental Mantle -50 to 2900 km -hot, dense rock -iron, magnesium, silicon, oxygen Core -2900 to 6371 km -iron & nickel -outer core is molten -inner core is solid Atmosphere -40 km -gaseous envelope, oxygen and nitrogen Hydrosphere -4 km -contains all ‘free’ water Biosphere -all living & non-living organic matter

38. Physical state is determined by the combined effects of pressure and temperature. Increasing temperature provides additional energy to the atoms and molecules of matter allowing them to move farther apart, eventually causing the material to melt. Increasing pressure raises the melting point of a material. Both pressure and temperature increase toward the center of the Earth, but at variable rates, causing Earth’s interior physical structure to vary accordingly 2-1The Earth’s Physical Structure

39. 2-1The Earth’s Physical Structure Lithosphere -crust & outer mantle -pressure high, temp low -rocks are rigid Asthenosphere -mantle to ~ 350 km -temp high enough to melt -weak, plastic rock Mesosphere -below Astheno -pressure high, mp raised -rocks are rigid Outer core -temp high -rock is melted Inner core -pressure high, mp raised -solid iron & nickel

40. Physiography and bathymetry (submarine landscape) allow the sea floor to be subdivided into three distinct provinces: –continental margins –deep ocean basins –midoceanic ridges. 2-2 The Physiography of the Ocean Floor

41. 2-2 The Physiography of the Ocean Floor

42. Continental margins: - submerged edges of the continents - consist of massive wedges of sediment eroded from the land and overlying water and deposited along the continental edge - Features include: *Continental shelf *Continental slope - submarine canyons. *Continental rise. 2-2 The Physiography of the Ocean Floor

43. Deep Ocean Province -is between the continental margins and the midocean ridge -Features include: *Abyssal plains: flat & covered w/ sediment. *Abyssal hills : buried volcanoes < 1 km tall. *Seamounts & guyots: buried volcanoes >1km tall, some w/ tops eroded. *Deep sea trenches: deepest on Earth; earthquake sites along ocean margins. 2-2 The Physiography of the Ocean Floor

44. Midoceanic Ridge Province: - continuous submarine mountain range. -covers ~1/3 of the ocean floor & extends ~ 60,000 km around Earth. -Features include: *Rift valley: opposite sides of ridge pulled apart form valley in center. *Transform fault : offset ridge segments- active. *Fracture zone : inactive TF moved out into ocean basins. 2-2 The Physiography of the Ocean Floor

45. How do continents and ocean basins differ? -Crustal composition: -Continentscoarse-grained igneous granite2.7 – 2.8 g/cm 3 -Ocean basinsfine-grained volcanic basalt2.9 g/cm 3 -Mantle rock is denser, ~3.3 g/cm 3 -Moho discontinuity- boundary of crust & mantle (deeper over continents, 35km, versus 5 km over ocean) 2-2 The Physiography of the Ocean Floor Granite -igneous rock, formed from molten rock. Basalt -volcanic origin; denser than granite.

46. How do continents and ocean basins differ?: - Elevation: -Bimodal distribution: 29% of Earth’s crust is above sea-level, 71% below. 2-2 The Physiography of the Ocean Floor

47. 2-2 The Physiography of the Ocean Floor

48. How do continents and ocean basins differ?: - Elevation (height) and composition (density): -Isostatic Balance (isostasy) -P = gh -Pressure (P) is equal to force of gravity (g) x density () x height of water (h). -Assume that the force of gravity (g) is the same everywhere (is constant). -Then a balance between  and h maintains constant P at bottom of container. -If  is high, then h must be low. -If  is low then h must be high. -i.e., h of continental crust is > h of ocean crust, because the of continental crust < of ocean crust. 2-2 The Physiography of the Ocean Floor

49. Isostasy refers to the balance of an object “floating” upon a fluid medium. Height of the mass above and below the surface of the medium is controlled by the thickness of the mass and its density (similar to ice floating in water). 2-3 Geologic Differences between Continents and Ocean Basins

50. Isostasy Greater the density of the mass, the lower it will sink in the medium. Greater the thickness of the mass, the higher a portion of it will rise above the medium. 2-3 Geologic Differences between Continents and Ocean Basins

51. Sea floor is thin (4 to 10 km), has greater density and does not rise as high above the mantle. Continents are thick (30 to 40 km), have low density and rise high above the supporting mantle rocks. 2-3 Geologic Differences between Continents and Ocean Basins Oceanic Crust Versus Continental Crust

52. Echo sounding and side-scan sonar. seismic reflection Seismic refraction altimetry 2-5Geophysical Surveying

53. Echo sounding and seismic reflection rely on sound pulses that reflect off the ocean floor and off sedimentary layers. 2-5Geophysical Surveying

54. 2-5Geophysical Surveying Seismic reflection reveals sub-surface features.

55. Seismic refraction examines how sound waves are bent (refracted) as they travel through material. They reveal densities, depths, and thicknesses of rock layers. (penetrates deeper than seismic reflection) 2-5Geophysical Surveying

56. 2-5Geophysical Surveying END OF LECTURE 1

57. 1-2 Historical Review of Oceanography