1. Oceans
The Last Frontier

2. Ocean Facts About 71% of Earth’s surface is covered by water
Average depth of the Pacific Ocean = 4,638 m
Average depth of the Atlantic Ocean = 3,872 m
Average temperature = 3.9°C (39.0°F)
Age of oceans = 4 billion years

3. Salinity in Oceans Salinity Average salinity in oceans = 35 ‰
Total amount of dissolved solids expressed in grams in 1 kg of water
Average salinity in oceans = 35 ‰
35 parts per thousand (ppt)
35 g/kg
Salinity variations
Due to differences in local rates of evaporation and precipitation (water budget)

4. Constituents of Sea Water
Most abundant seawater elements are sodium (Na+) + chloride (Cl-)
Major constituents: SO42-, Mg2+, Ca2+, K+, and HCO3-
Minor and trace elements also present

5. Salts in the Ocean Why is the ocean salty? Salts come from:
River discharge
Volcanic eruptions
Why is the ocean not getting saltier?
Salts going in = salts going out

6. Salts Going Out Sea Sra Sea Spray Evaporites Biological Adsorption
Fecal pellets
Shell formation
Adsorption
Mid-ocean ridge magma

7. Factors Affecting Salinity
Precipitation
Evaporation
River runoff
Freezing

8. Principle of Constant Proportions
The amount of salt varies, but the relative proportions of ions are constant
Because of this principle, it is necessary to test for 1 salt ion (usually Cl) to determine total amount of salt present

9. Determining Salinity 1. Calculating Salinity
Salinity= x chlorinity (‰)
2. Salinometers
Salinity determined by the electrical conductivity produced by dissolved salts

10. Oceans II
Surface Currents

11. Heat Variations Latitude
Depends on angle sunlight hits surface
Sunlight at polar latitudes covers wider area; therefore, less heat
At equator, sunlight covers less area; more heat

12. Heat Transfer Heat is transferred from equator to poles
Air Circulation
Ocean currents

13. Origin of Currents Ocean surface currents are wind driven
Air movement due to less dense air rising and more dense air sinking
Horizontal air flow along Earth’s surface is wind
Air circulating in this manner is convection currents

14. Wind Movement Non-rotating Earth
Simple wind pattern
Warm air rises at equator, flows toward poles
Air cools at poles, sinks, and flows toward equator
Winds named by direction from which they blow
North-blowing winds = southerly winds
South-blowing winds = northerly winds

15. Wind Movement Rotating Earth
At equator, warm air rises
Zone of low pressure
Clouds and precipitation
Reaches troposphere and moves poleward
As it spreads, it cools
30° N&S, cool air sinks
Area of high pressure
Dry conditions
Location of world deserts
60° N&S, air masses meet
Form Polar Front
Air masses rise, diverge and 90° and 30° N&S

16. Wind Movement At equator, warm air rises, condenses and precipitates
At 30° and 90°, cool air sinks
Air that sinks does not flow back in a straight north-south path – it curves (Coriolis Effect)

17. Rotation on a Globe
Buffalo and Quito located on same line of longitude (79ºW)
Both cities circles the globe in one day (360º/24 hours = 15º/1 hour)
Quito has larger circumference; thus, travels farther
Quito needs to travel faster than Buffalo

18. Apparent Deflection Hypothetical war game
If a cannonball is shot north from Quito
It will travel a straight path
But, because Earth is rotating east to west
The cannonball appears to veer to the right in Northern Hemisphere
This is the Coriolis Effect

19. Wind Movement Coriolis Effect
Deflected winds due to movement over spinning object
Produce wind bands
In Northern Hemisphere:
Winds are deflected to the right
Travel clockwise around high P
In Southern Hemisphere:
Winds are deflected to the left
Travel counter-clockwise around high P
Assume water-covered Earth

20. Surface Current Circulation