1. Oceanography

2. Oceanography 71% Earth’s surface is water
61% Northern Hemisphere is water
81% Southern Hemisphere is water
Average temperature 39o F
Average depth 12,451 feet
Average land elevation 2772 feet

3. Formation of Oceans Earth the Biography: Oceans Volcanic outgassing
Water vapor given off
Cooled and condensed
Comets colliding with Earth

4. Significance of Oceans
Maintaining Earth’s temperature
-70o C to 55o C
Mercury -180o to 430o C
Absorbs heat from sun
Currents move hot to cold
Air temperature
Coastlines more moderate
Inland more extremes
Water loses / gains heat slower than Land

5. Significance of Oceans
Biodiversity
Majority of all Earth’s Biomass
Source food and oxygen
Vast complicated food web
Water Cycle
Starting point Earth’s water cycle

6. Salinity Salts 3.5 % mass of oceans Varies with location Affected by
Mouth river – lower
Dead sea – 30%
Location in water column
Affected by
Precipitation
Sea ice / Icebergs melting
Runoff from land
Evaporation
Formation of sea ice

7. Ocean Temperature Varies with amount solar radiation received
Function of latitude
Varies with depth
Thermocline
Layer of ocean 300 m to 1000 m
Rapid change of temperature with depth
Creates barrier to marine life

8. Density Density = mass per unit volume Seawater density affected by
Salinity
Temperature
Varies with depth
Pycnocline
Layer ocean water 300 – 1000 meters
Rapid change of density with depth

9. Composition Na Mg
other Cl Ca S

10. Water Columns Photic zone Epipelagic zone Sunlight zone
Depth sunlight penetrates
Down to 200 meters
Photosynthesis
Highest amount of nutrients and energy

11. Water Columns Disphotic zone Mesopelagic zone Twilight zone
Scarce light
200 – 1000 meters down
High pressures

12. Water Columns Aphotic zone Midnight zone Bathypelagic zone
90% of the ocean
No light – no photosynthesis
Few life forms
Extremely high pressures

13. Water Zones littoral High tide to low tide Constant motion
Intertidal zone
littoral
High tide to low tide
Constant motion
Exposure to large amounts of air

14. Water Zones sublittoral From intertidal zone to end continental shelf
Neritic
sublittoral
From intertidal zone to end continental shelf
Oceanic plants
High primary production
Majority of sea life

15. Water Zones Begins at end of continental shelf
Oceanic zone
Begins at end of continental shelf
Steeper dive to ocean floor
Mostly no sunlight
Sharks, whales, etc.