5: Ocean Waters

5: Ocean Waters

1. 96.5% of water is oceans (saline)

   • sea salts
     • 55% cholride
     • sodium 30.6%
     • sulfate 7.7%
     • magnesium, calcium, potassium, minior constituents
   • seawater
     • salt: 3.5%
     • steady state
       • when rate at which substance is added equals rate its removed
       • residence time
         • residence time is mean length an atom spends in ocean before being removed
     • deposits commonly formed from evaporated seawater
       • anhydrite
         • CaSO4
       • gypsum
         • CaSO4 - 2H2O
       • Sylvite
         • KCl
       • Halite
         • NaCl
       • less common deposits from through chemical interaction with limestone (CaCO3)
         • Magnesite
           • MgCO3
         • Dolomite
           • MgCa(CO3)2
         • beach, sabkha place, sea salt evaporites
     • Salinity
       • polar regions are very low
         • river regions are emptying out there, poor mixing
           • around river mouths/delta
             • ice build up, ice melting
       • meditteranean is very briny
         • leftover of what was once a large ocean
           • enormous about of evaporation
             • runoff of water does not make up what is evaporated
       • variations
         • precipitation
         • very few organisms can endure extreme changes in salinity
         • freshwater run off from land
         • melting glaciers, sea ice
         • evaporation
     • dissolved gases
       • nitrogen
         • 78%
           • 11%
         • oxygen
           • 21%
             • 6%
           • carbon dioxide
             • 0.037%
               • 83%
       • in air
         • in ocean
       • saturation solubility
         • max amount of gas that can be dissolved in sewater
           • given specific temp, salinity, and pressure
             • as temp and salinity rise, sat solu go down
               • as pressure rises, sat solu goes up
                 • as age of water goes up, co2 rises and o2 lessens

2. freshwater

   • 50.7% glacial ice
   • 48.9% groundwater
   • 0.4%
     • soil moisture
     • permafrost
     • lakes
     • atmosphere
     • organisms
     • rivers
     • swamps

3. chemical bonds

   • NaCl: ionic bond
   • H2O covalent bond (strongest)
   • H2O2 intermolecular van der waals bonds (weakest)
   • multiple H2O: hydrogen bond
     • hydrogen bonds with N O or F
       • bond with water is strongest
   • heatcapacity
     • water has unusually high
     • gains/loses more heat when undergoing than any otherearth liquid
   • thermal expansion
     • water ice is less dense than liquid water
     • max density at 4 degrees c
   • surface tension
     • higher than any other known liquids except mercury
   • physical states
     • only substance present as gas, liquid, solid within natural temp ranges on earth
   • solvent property
     • can dissolve more substances tha nany other liquid
     • crystal latic pulled by water molecules (hydration)

4. properties

   • seawater
     • purewater
   • pH
     • 8.1 (alkaline)
       • 7.0 (neutral)
     • Densiity
       • 1.028 g/cm3
         • 1.000 g.cm3
       • freezing point
         • -1.9c/28.6f
           • 0c/32f
         • boiling point
           • 100.6c/213.1f
             • 100c/212 f