Transcript Oceanography

Oceanography
Earth’s Oceans
Earth is a special planet because of
liquid water
 71% of earth’s surface is water
 Ocean divided by continents
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4 Major Ocean Divisions
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Pacific Ocean
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Atlantic Ocean
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322 million cubic kilometers
Indian
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Volume 724 million cubic kilometers
292 million cubic kilometers
Arctic
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12 million cubic kilometers
Ocean Formation
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Two theories
Out-gassing
 Big Splat
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Out-gassing
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Volcanic vents released gases that cooled
to form our oceans
Big Splat
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Extraterrestrial comets delivered our water
Plate Tectonics Effect on Oceans
Plate tectonics causes lithosphere to
move
 As crust changes, oceans change shape
 245 mya continents formed Pangaea
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Oceans formed Panthalassa
Characteristics of Ocean Water
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Chemical composition is similar to
NaCl, Sodium Chloride, table salt
 Chlorine is the most abundant element
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Salinity
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Measured amount of salt and solids in a
given amount of liquid
Factors affecting Salinity
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Evaporation
Hot dry climate increases evaporation
 Less water more salt = high salinity
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River outlets/precipitation
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Increase of fresh water dilutes ocean water
= lower salinity
Currents
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Currents mix water causing water to
become diluted = lower salinity
Temperature Zones
Water Column: vertical aspect of ocean
 As depth Increases
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Pressure increases, Temperature decreases
3 Zones
Surface
 Transition/Thermocline
 Deep zone
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Surface Zone
Warm top layer
 Extends down 300 meters
 Sunlight warms only top 100 meters
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How does zone maintain temperature?
Average temp is 24°C
 Varies with latitude and time of year
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Rather swim near Alaska or Florida?
 Swim during summer or winter?
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Transition/Thermocline
Range is 300 to 700 meters
 Water temp decreases the greatest in
this zone
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Begins at 24°C
 Ends at 5°C
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Deep Zone
Range 700 to ocean floor 1,200 Meters
 Average temp is 2°C
 Deepest part of the ocean is below
zero, yet water doesn’t freeze, why?
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Water Cycle
Cycle that links all Earth’s solid, liquid
and gaseous water. 3 parts are:
 Condensation
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Precipitation
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Gas to a liquid
Solid or liquid water falls to earth
Evaporation
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Liquid to a gas