[2] Ocean Chemistry

• Five ocean components:

  1. Solutes
  2. Nutrients
  3. Gases
  4. Trace elements
  5. Organic compounds
• This is the ocean component that differentiates saltwater from freshwater

  Solutes
• Average pH of the ocean: pH 8
• Six major ions + bonus ion:

  1. Sodium
  2. Magnesium
  3. Calcium
  4. Potassium
  5. Chloride
  6. Sulfate
  7. Bicarbonate
• Average salinity of the ocean: 35 ppt
• Due to lower pH, there are less skeletons that can persists in deeper water
• There are 2.5 x 10^12 kg of annual salinity runoffs from terrestrial sources
• Isolated salt deposits caused by ocean saturation

  Evaporites
• Two examples of halites (chemical formula)

  NaCl and CaSO4
• Primary avenue for salt loss

  Adsorption
• Process wherein ions attach themselves to substrates like clay and ferromanganese

  Adsorption
• Colder water holds ions in solutions better, trapping CO2 and causing more acidity
• Factors affecting gas concentrations:

  A) Wave and current turbulence

  B) Difference in gas concentration

  C) Temperature

  D) Salinity

  E) Pressure

  F) Photosynthesis

  G) Respiration

  H) Decomposition

  I) pH

  
• T or F: Saltier water can lie above less salty water

  True
• The O2 minimum is consistent with the pycnocline around 1km
• The density differential of the pycnocline slows the movement of organic material
• Oxygen minimum zone (OMZ): A region where oxygen levels are low due to high rates of respiration by microbes.