2.  Total amount of salts dissolved in seawater  Salinity is expressed as the number of grams of salt left behind when 1,000 grams of seawater are evaporated.  If 35 grams are left behind then the salinity is 35‰.  ‰ = part per thousand

3.  Salinity can be increased by the evaporation and freezing which leave salts behind.  Salinity can be decreased by the addition of freshwater.  The average salinity of the world’s oceans is 35‰.

4.  Freshwater: less than.5 ‰  Brackish:.5 to 17 ‰  Seawater: 17 – 40 ‰  Brine (hypersaline): greater than 40 ‰

5.  Lack of Rainfall and a high evaporation rate (increases salinity) -Red Sea- 40‰-Mediterranean Sea- 38‰  High influx of fresh water and low evaporation rate. (decreases salinity) -Black Sea- 18 ‰-Baltic Sea- 8 ‰

6. How did the oceans and seas become salty?  The dissolved salts are produced by weathering of rocks and geothermal activity (undersea volcanoes, hydrothermal vents, etc…).  When the ocean water evaporates it leaves the salts behind and therefore the salinity increased over time.

7. http://www.palomar.edu/oceanography/salty_ocean.htm

8.  Mainly composed of six different ions (99%)  Chloride (Cl - ): 55.03%  Sodium (Na + ): 30.59%  Sulfate (SO 4 -2 ): 7.68%  Magnesium (Mg +2 ): 3.68%  Calcium (Ca +2 ): 1.18%  Potassium (K + ): 1.11%  Sodium and Chloride account for nearly 85% of the dissolved ions, that is why seawater tastes like salt (NaCl).

9.  Hydrometer: instrument that measure the specific gravity of a liquid.  Specific gravity: ratio of the density of one liquid to another.  Water is usually the reference liquid since it is 1 g/ml.

11.  Freshwater- 1.000 –1.010  Brackish- 1.010-1.020  Seawater- 1.020-1.030  Hypersaline (Brine): > 1.030

12.  Salinity is not always even throughout the water column.  There are sometimes differences in salinity due to evaporation or addition of freshwater.  Since different salinities have different densities you have stratification (layering).  Sometimes this causes the layers to remain separate and does not allow mixing to occur.