1. Ch. 15 Sec. 1 The Oceans

2. Oceanography Scientific study of the earths oceans Scientific study of the earths oceans Challenger: British research ship Challenger: British research ship –First to use sophisticated measuring devices –Investigated currents, temp, chem. Composition

3. Meteor: German research ship Meteor: German research ship –First to use sonar to map the sea floor –Sound Navigation Ranging

4. Submersibles use a side-scan sonar to investigate deep ocean trenches Submersibles use a side-scan sonar to investigate deep ocean trenches

5. Oceanography Topex/Poseidon: advance satellite Topex/Poseidon: advance satellite –Monitor ocean surface temps, currents, and wave conditions

6. Origin of Oceans – 2 sources Comets  Meteorite when hits surface Comets  Meteorite when hits surface –Collide with earth releasing water –Meteorites contain.5% water –Earth is 4.6 bil yrs old

7. Origin of Oceans Volcanism: Volcanism: –Violent eruptions period over hundreds of millions yrs. –Release CO 2 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

8. Earths Water 97% Salt Water 97% Salt Water 3% Fresh Water: Ice caps 3% Fresh Water: Ice caps Global sea level rises and falls through time Global sea level rises and falls through time Rise: Rise: –Melting of ice caps during warming periods –Rising of the earths crust Falls: Falls: –Freezing and expansion of glaciers during ice ages –Lowering of the earths crust Now: Rising about 1-2 mm a year Now: Rising about 1-2 mm a year

9. Water Blue Planet Blue Planet –One large ocean – 61 % covered in N. Hemisphere –81 % covered in S. Hemisphere

10. Water Major Oceans: Major Oceans: –Pacific, Atlantic, Indian, Artic and Antartic Seas: Seas: –Smaller b/c they are land locked