1. Salinity of the Ocean Notes

2. Why is the ocean salty?

3. Sources of Dissolved Solids
1. Ash from volcanic eruptions
Weathering of rocks on land
Hydrothermal vents

4. Salinity The amt. of dissolved solids in a liquid.
Unit that salinity is measured in is parts per thousand (ppt or ‰)
Average ocean salinity is 35ppt.

5. Dissolved Solids (sea salts)
85% of the dissolved solids are sodium chloride
6 most abundant elements
chlorine -
sodium -
magnesium -
sulfur -
calcium -
potassium - Cl Na Mg S Ca K

6. Are the oceans getting saltier?
The oceans are in a “steady state” b/c the concentration of salts have been about the same for about 1.5 billion years.
the removal rate of salts = the input rate.

7. How are salts removed from the ocean?
Evaporation deposits left behind when shallow seas dry up.
Biological processes & chemical reactions.

8. Slight Changes in Ocean Salinity
Precipitation (high precipitation = ____ salinity) Evaporation (high evaporation = _____ salinity) Freezing Freezing water = _____ salinity
lower
higher
higher

9. Affects of Salinity on Water
Adding salt to water… _____ the freezing temp. _____ the boiling temp. _____ the conductivity.
Lowers
Raises
Raises

10. Zones of the Ocean
Thermocline - A layer where the TEMP. rapidly decreases w/ depth.
Halocline - A layer where the SALINITY changes rapidly w/ depth.
Pycnocline - A layer where the DENSITY increases rapidly w/ depth Usually corresponds closely to the halocline &thermocline.