Ocean Water Chemistry Section 13.3

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

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)

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)

Effects of salinity Lower freezing temperature (-1.9oC) Higher density Greater bouyancy

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)

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

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