I. The Salty Ocean
A. Salinity
1. On average, one kilogram of ocean water contains
about 35 grams of salts. That is 35 parts per thousand.
2. Total amt of dissolved salts in a sample of water is the
salinity of that sample.
WHAT IS SALINITY?
3. Table salt (sodium chloride) is present in the ocean.
4. Chloride and sodium make up almost 86% of ions in
ocean water.
5. Ocean water also contains smaller amts of magnesium,
calcium and other substances.
6. p. 373
B. Variations in Salinity
Most parts of the ocean’s salinity is 34 and 37 parts
per thousand.
2. Near the surface, rain, snow, and melting ice add
fresh water which lowers the salinity.
3. Salinity is also lower near the mouths of large rivers
such as the Amazon or Mississippi. These rivers
empty large amts of fresh water into the ocean.
1.
Teach Time
Tell your neighbor where the ocean water has less
salinity and EXPLAIN WHY. (Must be at least two
places).
4. In hot and dry climate, evaporation causes salinity to
be higher. Ex: Dead Sea
5. Salinity is also higher near the poles where the
surface water freezes into ice, and the salt is left
behind.
Teach Time
Explain why the ocean has a greater salinity in a hot and
dry region.
Explain why the ocean has a greater salinity near the
poles.
C. Effects of Salinity
Ocean water does not freeze as quickly as fresh water,
because salt acts as an antifreeze.
2. Saltwater has higher density than fresh water.
3. Saltwater has a higher mass and buoyancy than fresh
water. Why?
1.
Salt Water
II. Other Ocean Properties
A. Temp of ocean water drops as you get deeper, and as
you travel away from the equator towards the poles.
B. Carbon Dioxide is 60% more plentiful in the ocean
than in air, b/c algae, corals, etc… need it.
C. Oxygen is scarcer in seawater than in air. It’s most
plentiful near the surface.
WHY DOES THE OCEAN WATER NOT FREEZE AS
QUICKLY AS FRESH WATER?
III. Changes with Depth
A. Decreasing Temp.
1. surface zone- warmest
2. transition zone- temperature drops very quickly.
3. deep zone- coldest
B. Increasing pressure- pressure increases continuously
as you get deeper in ocean.
C. Cold waters contain more oxygen than warm.
D. Why does warm water stay at the surface?
E. A vertical section of the ocean is
called the water column.
Pg. 376
Teach Time
Teach your neighbor:
What happens to the temperature of the ocean as you
get deeper? Why?
What happens to the pressure of the ocean as you get
deeper? Why?
Benthos, Nekton, Plankton