1. Properties of Seawater Oceanography Unit #2

2. Water (& Hydrogen bonding)  Molecules form hydrogen bonds w/ each other.

3. H20H20H20H20

4. Water (& Hydrogen bonding)  Molecules form hydrogen bonds w/ each other.  w/o hydrogen bonds, water freezes at -100° C.  w/o hydrogen bonds, water boils at -80° C.  High heat capacity.  Absorbs great deal of heat when evaporates.  Transparent.  Red wavelengths absorb first, blue last.

5. Absorption of Light

6. Marine Temperatures

7.  Seawater temps vary between about -3° C and 30° C.  < 0° C possible because saltwater freezes at colder temps.  Ideal organismal temp is between 0°C and 30 °C.  Temp ranges:  85°CThermal vents  40°CTropical lagoons  20°CSubtropical surface water  15°CTemperate surface water  5°CSub-polar surface water  0°CPolar surface water  -3°CAntarctic bottom water

8. Salinity  Amount of “salt” dissolved in water.  Includes inorganic salts, gases, and organics.  Expressed in ppt (‰), parts per thousand.  Ocean’s salinity ranges from 0‰ to 40‰.

9. Major Dissoved Ions

10. Salinity  Amount of “salt” dissolved in water.  Includes inorganic salts, gases, and organics.  Expressed in ppt (‰), parts per thousand.  Ocean’s salinity ranges from 0‰ to 40‰.  Increase salinity by:  Removing water during evaporation  Removing water during freezing  Decrease salinity by:  Add water during precipitation  Add water during thawing  Add water by river runoff

11. Seawater’s Density  Pure fresh water has a density of 1.0 gm/cm 3  Increasing salinity increases density of water.  Decreasing salinity decreases density of water.  Temperature effects on water’s density:  Water above 4°C, density increases with decreasing temp.  Water below 4°C, density decreases with decreasing temp.  Densest water is 4°C.  Least dense water is 0°C (ICE.)  WHY?

12. Water Freezing

13. Pressure  Sea level pressure = 14.7 lbs/in 2. (atmospheric)  Pressure under water increases w/ depth.  Every 10 m (33 ft.), adds another atmosphere of pressure.

14. Pressure