Earth Science
Water on Earth
Water Distribution
Study Tip
Studying diagrams for this topic will help you visualize the relative amounts of water.
Distribution
Earth’s oceans contain 97% of the planet’s water.
That leaves just 3% as fresh water (water with low concentrations of salts).
Most are trapped as ice in vast glaciers and ice sheets in Greenland.
Study Tip
Studying diagrams for this topic will help you visualize the relative amounts of water.
Reservoirs
A reservoir is a storage location for a substance (e.g. the atmosphere is a reservoir for carbon dioxide).
A water molecule may pass through a reservoir very quickly or may remain.
The
residence time
is the amount of time a substance remains in a reservoir.
Concept Check
Compare the amount of fresh water to the amount of salt water.
What is the relationship between reservoir and residence time?