…methods to get Fresh Water out of ocean water Desalination –Distillation –Reverse Osmosis Freezing …we get 13 million liters DAILY from the ocean!

Ocean Resources20.3

…methods to get

Fresh Waterout of ocean water

•Desalination–Distillation–Reverse Osmosis

•Freezing•…we get 13 million liters DAILY

from the ocean!

Distillation• Boil sea water to

vapor (H2, O2)

• Condense the vapor to pure H2O

• Requires lots of energy

Heat...

condense...

Collect the pure H2O!

evaporate...

Desalination in Japan

…fresh water!

Freezing• Freeze sea water to -

2oC• Salt is pushed out of

the ice crystals as they form-

• Melt ice to get pure H2O

• One-sixth the energy cost of distillation

…fresh water!

Reverse Osmosis• Pump sea water

through filters (membranes) that block salt, but allow H2O molecules through.

• The newest & best technology available.

Filtering System• Different layers of the

filter• The first filter gets

the largest objects out of the water

• The last filter layer called the membrane rejects the salt

Reverse Osmosis

…fresh water!

CONSERVATION is still the cheapest

way…don’t waste fresh

water!

Mineral Resources• Nodules of Mn, Fe,

Cu, Ni, Co, & phosphates form on the abyssal plain (grow 1 mm every million years!)

• ALSO - we mine salt, bromine, & magnesium...

…but the “big daddy” is PETROLEUM!

• Oil, that is…• Black gold,Texas

tea…• 25% of world oil

supply comes from offshore drilling on the continental shelves.

* Gulf of Mexico

* North Sea

* Persian Gulf

* Alaska Coast

*California Coast

AQUACULTURE• The farming of the ocean• 1/2 billion people world-wide

suffer from lack of protein• Ocean farms can produce much

more protein-rich food per acre than land farms

• Problems: pollution…

Japanese prawn

farm Farm-raised Vietnamese catfish

Miqmak Indians raise salmon in Newfoundland

Artificial upwelling

•Nutrient-rich bottom water can be pumped up to surface to fertilize the surface