1. Earth’s Oceans

2. 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

3. Oceans Modern Oceanography Sonar Satellites
Today we can use SONAR and satellites to study the oceans.
Satellites such as the Topex/Poseidon monitor the ocean’s surface temperatures, currents, and wave conditions.
Satellites
Modern Oceanography
Sonar

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

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

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

7. 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)

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

9. 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

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

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

12. 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.

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

14. Gulf Stream From North America to Europe, follows the
“Westerlies” as a Surface
Current.
300x flow of Amazon
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

15. Gyres - circular ocean currents caused by landmasses
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

16. Tides
Tides - the periodic rise and fall of ocean levels

17. 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

18. 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

19. Breakers- waves whose bottom is moving slower than the top due to friction