Ch. 21.3 Ocean Resources

The ocean is an important source of fresh water, minerals, and food.

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.

Freezing—when 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 Osmosis—when water passes through certain membranes under pressure, only the pure water passes through.

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 world’s oil production is from offshore wells.

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.

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.