Discovering Earth's Topography and Oceanic Circulation

1. The Ocean Init 2/17/2010 by Daniel R. Barnes WARNING: This presentation contains graphical and audio elements taken without permission from the world wide web. Do not copy or distribute this presentation. Its very existence may be illegal.

2. Geography CONTINENTS AND OCEANS ? ? Europe Asia North America Mediterranean Sea ? ? Atlantic Ocean ? Africa ? PacificOcean ? South America ? ? Australia Indian Ocean ? ? Atlantic Ocean ? Antarctica

3. Geography FAMOUS LOCATIONS Los Angeles New York City West sa-eed!

4. Geography FAMOUS LOCATIONS Greenland Siberia Norway & Sweden Alaska Iceland Italy Japan China Los Angeles Himalayas New York City Egypt India Hawaii Philippines Brazil

5. HISTORICAL ASIDE: Countries that were at some point part of the BRITISH EMPIRE Sorry, Erlis. Turkey is grey on this map. It has never been a possession of the British. It looks like the Brits owned the island of Cyprus at some point, though. That’s close to Turkey.

6. HISTORICAL ASIDE: Countries that, in 1683, were part of the OTTOMAN EMPIRE Grand Vizier Köprülü Fazıl Ahmed Pasha It looks like you were just thinking of the wrong empire.

7. . . . but we digress . . .

8. Seafloor Topography Topography is . . . . . . the study of the shape of the earth’s surface The sea floor has just as much topographic diversity as dry land does . . .

9. Seafloor Topography Dry Land Ocean Floor Mountains Valleys Plains Volcanoes Faults Plateaus

10. Seafloor Topography The deepest parts of the ocean are colored . . . . . . dark blue on this map. These deep, wide, dark, flat regions of the seafloor are called . . . abyssal plains

11. gulper eel

12. Is this one fake? gulper eel

13. Mid-Atlantic Ridge Seafloor Topography divergent plate boundary seafloor spreading Basaltic eruptions make new oceanic crust

14. pillow basalt

15. Seafloor Topography Mid-Atlantic Ridge Oceanic ridge Mid-ocean ridge

16. Seafloor Topography Grand Banks What are all the red zones? continental shelf shallow water often good for fishing

17. Seafloor Topography can easily become a land bridge . . . . . . when sea levels drop . . . continental shelf shallow water . . . during a glaciation phase of an ice age

18. Seafloor Topography can easily become a land bridge . . . . . . when sea levels drop . . . . . . during a glaciation phase of an ice age

19. This map has a different color code than the last one. This map has a different color code than the last one. On this map, what color are the continental shelves? On this map, what color is the mid-ocean ridge? On this map, what is in dark blue? On this map, what color are the highest mountains?

20. Volcanic eruptions can and do occur underwater . . . a LOT, in fact

21. Lava comes out and quickly solidifies when it touches the water.

22. Each layer of igneous rock adds size and mass to the volcano.

23. These undersea mountains are called “seamounts”.

24. If the magma supply from underneath doesn’t die out too soon . . .

25. The seamount will eventually get tall enough to become an island.

26. Islands have a tendency to become surrounded by coral reefs. Coral is an animal, even though it sits in place like a plant. However, coral polyps, which are basically jellyfish with their heads stuck to a rocky skeleton they secrete, do typically have tiny golden-brown algae living in them that photosynthesize. Therefore, coral must grow in clear, shallow, sunlit waters.

27. If the volcanic eruptions stop, the island stops growing, but weathering and erosion don’t stop, so the island shrinks. The island itself may shrink, but the ring of coral remains, since it’s alive, and can grow, if needed, to stay high enough to reach light. The ability to fight the forces of weathering and erosion are, in fact, a sign of life. Coral is a combination of rock and living tissue, so not only is it subject to normal weathering and erosion; it is also subject to being eaten . . .

28. The green humphead parrotfish eats algae that grows on coral, and also eats the coral itself. Because it eats coral, it poops out calcium carbonate sediment.

29. If eruptions have stopped, waves will wear the island away until its surface lies beneath the waves, but the coral keeps growing Once the island is worn down beneath the waves, coral can grow on top of it, turning the fringing reef from a doughnut shape into a solid disc shape (cookie?). It is now an “atoll”. The oceanic crust from which the island projects often begins to sink once the magma supply dies out. The coral keeps growing upward, creating more and more calcium carbonate skeleton, to stay high enough for light.

30. At some point, though, the crustal plate may sink so low that the coral can’t grow fast enough to stay in the light, and the reef dies. At this point, the submerged ex-island is no longer an atoll, but a guyot. Guyots are flat-topped seamounts that used to be islands.

31. enough of topography.

32. and now . . .

33. Oceanic Circulation Ocean Currents

34. Surface Currents e=mc2 Deep Currents

35. gyres North Atlantic Gyre North Pacific Gyre South Atlantic Gyre Indian Ocean Gyre South Pacific Gyre

36. Coriolis effect North Atlantic Gyre North Pacific Gyre South Atlantic Gyre Indian Ocean Gyre South Pacific Gyre

40. the end . . . so far

41. Seafloor Topography Europe Asia North America Atlantic Ocean Africa PacificOcean South America Australia Indian Ocean Atlantic Ocean Antarctica