1. 15.1 Notes – Composition of Seawater Thursday 12/2/10

2. Salinity ℓTotal amount of solids dissolved in water ℓWe usually think salt (NaCl), because it is the most common ℓComes from weathering of rocks and the interior of Earth ℓMeasured in ppt (parts per thousand or 0/00)

3. Changes in Salinity ℓIf the % of salinity changes, it is because the amount of fresh water has changed, because the amount of solids stays relatively steady ℓAddition of Water (decrease in salinity) = precipitation, runoff, icebergs melting, sea ice melting ℓSubtraction of water (increase in salinity) = evaporation, formation of sea ice

4. Temperature ℓVaries greatly due to amount of solar radiation ℓareas near equator are warmer, near poles are colder ℓSurface water is warmer than deep water ℓThe thermocline

5. Density ℓMass/volume (or how much stuff is in a given space) ℓTemperature increase > density decrease (water will expand as a liquid when heated) ℓSalinity increase > density increase ℓPycnocline