Transcript 15-1 Oceans

Ch. 15 Sec. 1
The Oceans
Oceanography
• Scientific study of the earths oceans
• Challenger: British research ship
– First to use sophisticated measuring devices
– Investigated currents, temp, chem.
Composition
• Meteor: German research ship
– First to use sonar to map the sea floor
– Sound Navigation Ranging
• Submersibles use a side-scan sonar to
investigate deep ocean trenches
Oceanography
• Topex/Poseidon: advance satellite
– Monitor ocean surface temps, currents, and
wave conditions
Origin of Oceans – 2 sources
• Comets  Meteorite when hits surface
– Collide with earth releasing water
– Meteorites contain .5% water
– Earth is 4.6 bil yrs old
Origin of Oceans
• Volcanism:
– Violent eruptions period over hundreds of millions yrs.
– Release CO2 and water vapor into air (early
Atmosphere)
– Earths crust cooled and condensed into oceans
– Water molecules released and destroyed by UV rays
keep a balance
Earths Water
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97% Salt Water
3% Fresh Water: Ice caps
Global sea level rises and falls through time
Rise:
– Melting of ice caps during warming periods
– Rising of the earths crust
• Falls:
– Freezing and expansion of glaciers during ice ages
– Lowering of the earths crust
• Now: Rising about 1-2 mm a year
Water
• Blue Planet
– One large ocean
– 61 % covered in N. Hemisphere
– 81 % covered in S. Hemisphere
Water
• Major Oceans:
– Pacific, Atlantic, Indian, Artic and Antartic
• Seas:
– Smaller b/c they are land locked