1. Chemical Oceanography
Water and Seawater Chemistry

2. Water molecule Water= H2O or H-O-H
Hydrogen bond allows water to have properties of cohesion and adhesion
Adhesion –water sticks to other things
Cohesion –water sticks to itself

4. Water temperature and Density
Density is amount of mass per unit of volume g/l
Lower temperature = more dense substance.
WATER IS DIFFERENT
Densest at 39* F--Freezes at 32* F
Even though it is colder, ICE FLOATS!!!

6. High Specific Heat Water heats up slowly and cools down slowly!
Moderates the climate of the Earth

8. Make-Up of Seawater
All of the elements in the periodic table are in seawater
96.5% pure water
3.5% dissolved salts
Salinity – measure of amount of salt dissolved in H2O
Measured as grams of salt in 1000g of seawater
Units are ppt (parts per thousand)

9. Temperature, salinity, and density
Seawater is heaver and denser than fresh water(easier to float in the ocean)
The combination of salt and temperature determines the density

10. Density layers of the ocean
Surface zone/ mixed layer - temperature and salinity are constant
Pynocline - density increases with depth
Thermocline - depth where water temperature changes
Halocline -zone of rapid salinity increase with depth
Deep zone -80% of sea water- density and temperature constant

12. Thermal Structure of the Ocean at 3 Latitudes

13. Influences of Salts
Lowers the freezing point of water, salts act as an antifreeze
Evaporates more slowly, salts are more attracted to water and therefore “hold on” stronger
Increases the density of the water: more salt = more mass per unit volume

14. Factors that affect salinity
Salinity is effected by the size of the body of water, the amount of freshwater added to it, and the rate of evaporation.
Average ocean salinity = 35 ppt

15. Ocean surface conditions
Evaporation in the tropics exceeds rainfall – makes water saltier
Evaporation in temperate and polar regions is LESS than rainfall – makes water more fresh
Water in the deep ocean is the same temperature, salinity, and density all over the world.

16. Surface Salinity of the Oceans and Worldwide Patterns of Evaporation
Evaporation – Precipitation cm/yr
Salinity ppt
Latitude South to North

17. Refraction and light in the ocean
The speed of light in water is ¾ its speed in air.
This bends the light waves causing light to bend (refraction)

18. Transparency How much sunlight can penetrate seawater
Transparency is dependent upon what and how much is suspended in water
How transparent the water is called turbidity. Cloudy = high turbidity.
EX: mud, plant life, anything that can block the light
Excessive river runoff can reduce transparency

19. Why are the oceans blue?
All colors of light (ROY G BIV) can penetrate seawater
Blue light is reflected the most
Therefore, the oceans appear blue
If the transparency is low, the oceans appear different colors

20. Sound in the ocean
Sound waves can travel farther in water than light waves
Many marine animals use sound to “see” under water rather than light.
The speed of sound increases as temperature and pressure increase.

21. Sonar Shadow Zone
Like light, sound refracts or bends as density of the water changes.
At about 80 meters an area forms, called a shadow zone, that is undetectable to sonar.

22. SOFAR Channel
Sound in the sea can often be “trapped” between ocean density layers and effectively carried very long distances.
The SOFAR channel is found within the thermocline layer of the ocean.

23. Make a highway billboard to advertise the unique properties of water.
You are a marketing director for a major advertising firm. You have been hired to sell the highly unusual substance, water.
Make a highway billboard to advertise the unique properties of water.
Must illustrate and describe at least 3 of water’s properties.
Illustrations must fill the entire poster
Must be colorful and attractive