Earth Science
Water on Earth
Distribution of Water on Earth
Study Tip
To help remember the function of reservoirs:
Reservoirs reserve
water.
Distribution of Water
Earth’s oceans contain 97% of the planet’s water
3% of Earth’s water is fresh water, water with low concentrations of salt
Most fresh water is trapped as ice in glaciers and ice sheets of Greenland
Study Tip
To help remember the function of reservoirs:
Reservoirs reserve
water.
Reservoir:
storage location for water
Can be an ocean, glacier, pond, or the atmosphere
Water molecule may pass through a reservoir very quickly or remain for much longer
Residence time:
amount of time a molecule stays in a reservoir
The distribution of Earth’s water
Concept Check
If Earth is the water planet, why is water sometimes a scarce resource?
What are the reservoirs for water?
In which reservoirs does water have the longest residence times? The shortest?