Ch. 21.3 Ocean Resources

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Ch. 21.3 Ocean Resources
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• The ocean is an important source of fresh water,
  minerals, and food.

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Fresh Water from the Ocean

• Fresh water is derived from ocean water through
  the process of desalination.
• Distillation is one method, in which the water is
  heated, causing evaporation, leaving the salts
  and minerals behind. When the water vapor
  condenses, the result is pure fresh water.

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• Freezingwhen ocean water freezes, the first ice
  crystals are free of salt. The ice is then
  removed and melted to obtain fresh water. Uses
  1/6th the energy of distillation.
• Reverse Osmosiswhen water passes through certain
  membranes under pressure, only the pure water
  passes through.

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Minerals from the Ocean

• Nodules containing manganese and other minerals
  are found on the abyssal plain.
• Salt, magnesium, and bromine are economically
  extracted from ocean water.
• Petroleum beneath the sea floor is the most
  valuable mineral resource. 1/4th of the worlds
  oil production is from offshore wells.

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Food from the Ocean

• Protein-rich food (fish) is found in the ocean.
• Aquaculture is the raising of marine fish and
  shellfish.
• Ocean farming could produce more food than a land
  farm of the same size.

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Ocean Water Pollution

• Garbage, sewage, and nuclear waste have been
  dumped into the ocean.
• Certain pollutants have been found in some marine
  organisms, and coastal waters are in danger.
• Past nuclear waste dumping continues to be a
  concern.