1. MenuPreviousNext 8 - 1 nA source of sea salts appears to be minerals and chemicals eroding and dissolving into fresh water flowing into the ocean. nWaves and surf contribute by eroding coastal rock. nHydrothermal vents change seawater by adding some materials while removing others. nScientists think these processes all counterbalance so the average salinity of seawater remains constant. nThe ocean is said to be in chemical equilibrium. The Inorganic Chemistry of Water Chapter 8 Pages 8-16 to 8-18 Why the Seas Are Salty

2. MenuPreviousNext 8 - 2 Salinity, Temperature, and Water Density nMost of the ocean surface has average salinity, about 35‰. Waves, tides, and currents mix waters to make them more uniform. nPrecipitation and evaporation have opposite effects on salinity.  Rainfall decreases salinity by adding fresh water.  Evaporation increases salinity by removing fresh water.  Freshwater input from rivers lowers salinity.  Abundant river input and low evaporation results in salinities well below average. The Inorganic Chemistry of Water Chapter 8 Pages 8-18 to 8-19

3. MenuPreviousNext 8 - 3 Salinity, Temperature, and Water Density nSalinity and temperature also vary with depth.  Density differences causes water to separate into layers.  High-density water lies beneath low-density water. The Inorganic Chemistry of Water Chapter 8 Pages 8-18 to 8-19

4. MenuPreviousNext 8 - 4 Salinity, Temperature, and Water Density nWater’s density is the result of its temperature and salinity characteristics:  Low temperature and high salinity are features of high- density water.  Relatively warm, low-density surface waters are separated from cool, high-density deep waters by the thermocline, the zone in which temperature changes rapidly with depth.  Salinity differences overlap temperature differences and the transition from low-salinity surface waters to high-salinity deep waters is known as the halocline.  The thermocline and halocline together make the pycnocline, the zone in which density increases with increasing depth. The Inorganic Chemistry of Water Chapter 8 Pages 8-18 to 8-19

5. MenuPreviousNext 8 - 5 Salinity, Temperature, and Water Density The Inorganic Chemistry of Water Global Salinity Chapter 8 Pages 8-18 to 8-19