1. Properties of Ocean Water & the Ocean Floor

2. Water density Maximum density at 4oC Ice less dense than liquid water
Atomic structure of ice
Ice floats
Increased salinity decreases temperature of maximum density

3. Seawater
Salinity=total amount of solid material dissolved in water (g/1000g)
Typical salinity is 3.5% or 35 o/oo or ppt
Brackish (hyposaline) < 33 ppt
Hypersaline > 38 ppt

4. Dissolved Gases in the Ocean
O2 high in surface ocean due to photosynthesis
O2 low below photic zone because of decomposition
O2 high in deep ocean because source is polar (very cold) ocean
CO2 low in surface ocean due to photosynthesis
CO2 higher below photic zone because of decomposition
Deeper seawater high CO2 due to source region and decomposition

5. Surface variations of salinity
Polar regions: salinity is lower, lots of rain/snow and runoff
Mid-latitudes: salinity is high, high rate of evaporation
Equator: salinity is lower, lots of rain
Thus, salinity at surface varies primarily with latitude

6. Vertical variations of salinity
Surface ocean salinity is variable
Deeper ocean salinity is nearly the same (polar source regions for deeper ocean water)
Halocline, rapid change of salinity with depth

7. Imagine you were walking along the ocean floor.
What would you see?
What would you feel?
What would you encounter?

8. Ocean Floor
Contains the world’s largest mountain range (40,000 miles long) & canyons deeper than the Grand Canyon
2 Major Regions:
Continental Margin: made of continental crust
Deep-Ocean Basin: made of oceanic crust

9. Ocean Floor Continental Margin: Continental Shelf Continental Slope
Continental Rise

10. Ocean Floor Deep-Ocean Basin: Abyssal Plain Mid-Ocean Ridges
Rift Valley
Ocean Trenches
Seamounts

11. Ocean Floor Features