1. Warm-up What is one topic from this unit that you understand?
What is one topic that you are still confused about?

2. Oceanography Review
Chapters 15 and 16

3. Oceans Oceanography- the study of Earth’s oceans
Water could have originated one of two ways on Earth:
Comets hitting Earth
Volcanic eruptions emitting gasses

4. Oceans Sonar Satellites
Today we can use SONAR and satellites to study the oceans.
Satellites
SONAR is used to measure ocean depth
D = ½ (time x velocity) d = ½ (sec x 1500m/sec) Speed of sound in water
Sonar

5. Oceans cover approximately 71% of the Earth’s surface
Ocean Water
Oceans cover approximately 71% of the Earth’s surface

6. Ocean Water Oceans cover about: 61% of the northern hemisphere
81% of the southern hemisphere
Northern Hemisphere
Southern Hemisphere

7. Chemical Properties of Seawater
Ocean water is made up of several different elements that make it “salty”

8. Chemical Properties of Seawater
Salinity is a measure of the amount of dissolved salts in seawater.
Salinity is measured in grams of salt per kilograms of water, or parts per thousand (ppt)

9. Chemical Properties of Seawater
The average salinity of seawater is 35 ppt or 3.5%

10. Chemical Properties of Seawater
Salinity can be increased by:
Weathering and erosion of rock
Volcanic activity
Evaporation
Salinity can be decreased by:
Precipitation
Runoff
Iceberg and sea ice melting

11. Ocean Layers
The ocean can be divided into 3 layers based on temperature
Surface layer
Transitional thermocline
Bottom layer
Surface Layer
Thermocline
Bottom Layer

12. Thermocline - a zone of rapid temperature change
Thermocline - a zone of rapid temperature change. As depth INCREASES temperature DECRESES

13. Water Density Water density is affected by temperature and salinity
Cold water is more dense and sinks to the bottom
Warm water is less dense and rises
Salinity
Higher salinity leads to increased density
Higher density water sinks.

14. Currents Density Currents- caused by
the differences in temperature and salinity in deep water
Surface Currents-
caused by winds.

15. Gulf Stream
Northern Hemisphere, currents flowing toward the pole are warm
Southern Hemisphere, currents flowing towards the pole are cold
Cold+salt = dense water
In the North Atlantic Ocean, the water becomes so dense - begins to sink down through less salty and less dense water: Density Current

16. Gyres - circular ocean currents caused
by landmasses and the Earth’s rotation
Coriolis effect – ocean currents in the northern hemisphere are deflected to the right and currents in the southern hemisphere are deflected to the left
Upwelling - Vertical movement of ocean water

17. Tides Tides - the periodic rise and fall of ocean levels
Normally there are 2 high tides and 2 low tides per day. This pattern is called a semidiurnal tide

18. Neap Tides Spring Tides
Occur when the Sun, Moon and Earth form a right angle.
High tides are lower, low tides higher than normal
Spring Tides
Occur when Sun, Moon and Earth are aligned
High tides are higher and low tides lower than normal

19. Ocean Waves
Wavelength- distance from one point to the same point on the next wave
Crest- top of a wave
Trough- bottom of a wave
Wave- rhythmic movement that carries energy through matter or space

20. Shoreline Features
A beach is the accumulation of sediment along the shore of a lake or ocean.
Waves are constantly eroding, transporting, and depositing sediment resulting in many shoreline features.

21. Shoreline Features
A barrier island is a long, narrow sandbar parallel to, but separated from, the mainland.

22. Shoreline Features
An estuary is the area where a river or stream enters the ocean. Causes brackish water- a combination of fresh and salt water.

23. Changes in Sea Level
Melting of glaciers and ice sheets causes global sea levels to rise.
Rising sea levels can cause flooding in coastal areas.

24. The Seafloor
The deepest place in the ocean is the Mariana Trench in the Pacific Ocean.

25. The Seafloor
The continental margin is the submerged part of a continent.

26. The Seafloor
The continental shelf is the shallowest part of a continental margin from the shore to the open ocean.

27. The Seafloor
The continental slope is the area where the seafloor drops off towards the abyssal plain. It is the true edge of the continent.
HERE!

28. The Seafloor
The continental rise is sloping accumulation of deposits that form at the base of the continental slope.
HERE!

29. The Seafloor The ocean basins make up 60% of the Earth’s surface.
An abyssal plain is a smooth, flat, bottom part of the ocean. They are the flattest surfaces on earth.

30. The Seafloor
A trench is a deep depression in the seafloor. The deepest parts of the oceans are found in trenches (This is where subduction occurs)

31. The Seafloor
The mid-ocean ridge is a chain of underwater mountains that run through the ocean basins.
A rift valley is the middle part of the mid ocean ridge.

32. A. Continent B. Submarine Canyon K. Continental Shelf
I. Volcanic Island
C. Continental Slope
D. Seamounts
H. Midocean ridge
E. Guyot
J. Rift Valley
G. Trench
F. Abyssal Plain