15.1 Notes

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15.1 Notes Composition of Seawater

• Thursday 12/2/10

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Salinity

• Total amount of solids dissolved in water
• We usually think salt (NaCl), because it is the
  most common
• Comes from weathering of rocks and the interior
  of Earth
• Measured in ppt (parts per thousand or 0/00)

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Changes in Salinity

• If the of salinity changes, it is because the
  amount of fresh water has changed, because the
  amount of solids stays relatively steady
• Addition of Water (decrease in salinity)
  precipitation, runoff, icebergs melting, sea ice
  melting
• Subtraction of water (increase in salinity)
  evaporation, formation of sea ice

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Temperature

• Varies greatly due to amount of solar radiation
• areas near equator are warmer, near poles are
  colder
• Surface water is warmer than deep water
• The thermocline

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Density

• Mass/volume (or how much stuff is in a given
  space)
• Temperature increase gt density decrease (water
  will expand as a liquid when heated)
• Salinity increase gt density increase
• Pycnocline