Ocean Water Chemistry

1
Ocean Water Chemistry

• Section 13.3

2
Salinity

• The amount of dissolved salt in water
• The ocean has 35g of salt per 1kg water
• or
• 35g salt per 1000g water
• or
• 3.5 salinity
• VIDEO

3
What kind of salt is in ocean?

• Most of the salt is sodium chloride which breaks
  up in to sodium ions and chlorine ions
• Other kinds of salt are in the ocean
• (sulfate, magnesium, calcium, potassium and
  others)

4
Variations of salinity

• Increased salinity
• - at surface (evaporation)
• - at poles (water freezes)
• Decreased salinity
• - at mouths of rivers (fresh water added)
• (Brackish water)
• - at surface (precipitation)

5
Effects of salinity

• Lower freezing temperature (-1.9oC)
• Higher density
• Greater bouyancy

6
Ocean Properties

• Temperature drops as you move away from equator
• Water is colder and denser the deeper you go
• CO2 is more plentiful than in air
• O2 is more scarce (especially in deeper and
  warmer water)

7
Temperature Zones

• Surface warmest (top 100-500m)
• Transition zone
• Temps drop quickly
• to 4oC (from surface
• to1km deep)
• Deep average temperature
• is 3.5oC

8
Pressure in ocean

• Pressure increases with depth
• Divers can only descend 40m
• Submersibles can go deeper