1. What do you know about oceans? Explain at least two things.
What do you know about our oceans?
Arctic Ocean
Baltic Sea
Persian Gulf
Bay of Fundy
Atlantic Ocean
Pacific Ocean
Indian Ocean
Antarctic Ocean
Oceans cover 2/3 of the Earth’s surface.
Fig. 16.1, p.400

2. Northern Hemisphere is approximately 39% land.
The Hemispheres of the Earth
Northern Hemisphere is approximately 39% land.
The Southern Hemisphere is approximately 19% land.

3. Topography There are mountains under the ocean larger than Mt. Everest
15CO, p.374

4. Mid-oceanic ridges
Trenches
Island arcs
Hot spots

5. Highest mountain Mt. Everest 8848 meters
Average elevation of continents
840 meters
Sea level
Average depth
of oceans
– 3800 meters
Floor of central oceans about
– 5000 meters
Deepest ocean trench Mariana trench – 11,000 meters
Millions of square kilometers
Percent of Area
Fig. 15.3, p.377

6. How do we map the ocean floor? Sonar and Radar
Sonar: measuring the time sound waves take to return to ship
Known facts:
travel time to bottom and back
Speed of sound in sea water
The distance is determined by plugging these values into a simple formula

7. Geosat satellite Launched in 1985 Orbits the Earth in about 14 hours
The Earth rotates
Satellite map of the Earth’s topography, 1.5 years
For every increase of 1000 meters on the seafloor, there is 1 meter increase in height of water.

8. Geosat image of the ocean floor

9. Active margin: contains a plate boundary

10. Variations in temperature:
From north to south due to the Sun’s radiation

11. Changes in the Sun’s angle cause variations in the amount of solar energy reaching Earth’s surface.

12. Variations in Sun’s rays with latitude

13. Layers of the Ocean: what determines the ocean’s layers?

14. Temperature: warmer at equator cooler near the poles
Surface temperature variations

15. Three layers: Mixed, Thermocline, Deep zone

16. Source of salts? Volcanic activity: outgassing
Chemical weathering of rocks (dissolved load)

17. Precipitation

18. Density determines the vertical position

19. Intertidal Zone Area between high tide line and low tide line
Organisms adapted to harsh, changing environments
Intertidal
Zone
Continental
Shelf

20. Neritic Zone Area over the continental shelf
Area of greatest density and diversity of marine life
Neritic
Zone
Continental
Shelf

21. Oceanic Zone From the continental break out to open ocean Oceanic Zone
Shelf

22. Lifestyles 3 Basic Lifestyles:
Plankton – float with currents. Can not swim
Nekton – Swim freely
Benthos – Crawl on the ocean floor. Can not swim

23. Plankton: microscopic animals and plants
Diatom-phytoplankton
bottom of the food chain
Use basic nutrients from sea water to produce skeletons and soft tissue
phytoplankton produce greater than 50%
Zooplankton
Copepod-1mm
Dinoflagellate- 250 microm.

24. Nekton (swimmers) 5 Categories: Reptiles Mammals Fish Arthropods
Mollusks

25. Nekton (swimmers)
Marine Reptiles:
Turtles
Snakes
Crocodiles
Iguanas

26. Benthos (bottom dwellers)
Vagrant:
Crabs
Sea Stars
Sea Cucumbers
Sea Urchins
Brittle Stars

27. Coriolis effect: earth’s rotation causes gyres

28. Gyres or circular patterns in the oceans create currents

29. Fig , p.407

30. Ocean currents influence climate

31. Tsunami – Great Wave