Chapter 3 - Global Distribution Resources and Use

70% of Earth’s surface is covered in water.
97% of water is located in the oceans.
3% of water is freshwater, most of the freshwater is located in the ice caps and glaciers.
Unique properties of water * Water has a high boiling point * A lot of energy is needed to evaporate water * Water dissolves many compounds * Water expands as it freezes * Water adheres to many solid surfaces

Freshwater * The places with the highest amount of freshwater are the places with high precipitation and small populations. * The places with the lowest amount of freshwater are the places with low precipitation and large populations. * The use of freshwater is growing at twice the rate of population growth.

Aquifers * Geologic feature that contains water in quantities sufficient to support a spring or well. * Holds 30 times more water in the US than all US lakes and rivers combined.
Important terms * Confined Aquifer - an aquifer below the land that is saturated with water. * Recharge Zone - The area above an aquifer that supplies water. * Unconfined Aquifer - An aquifer where the upper water surface is at atmospheric pressure * Unsaturated Zone - The zone immediately below the land surface that is not totally saturated with water. * Water Permeability - The ability of a material to allow passage through rocks with water * Water Table - The level below that ground is saturated with water.

Glaciers * Body of dense ice that only forms on land. * 99% of glacial ice is contained in ice sheets in polar regions. * Largest reservoir of freshwater in the world.
Ice Sheets * Mass of glacial ice that is greater than 20,000 square miles in area. * The only ice sheets are Antarctica and Greenland.
Ice Shelves * Thick floating platform of ice that forms when a glacier or ice sheet flows down to a coastline and onto the ocean surface. * Only found in Antarctica, Greenland, and Canada
Sea Ice * Frozen seawater. * It floats on the ocean surface. * It is found primarily in the Northern Hemisphere.

71% of the Earth’s surface is covered in oceans.
More than half of this area is under 10,000 feet.
Oceans have a significant effect on the biosphere, because oceanic evaporation is the primary source of precipitation.
Oceanic Circulation * Heat is transferred to the equator by ocean currents. * Warm waters near the surface and cold water deeper in the ocean move by convection currents.
The Great Ocean Conveyor Belt * There is constant motion in the form of a global ocean. * Cold water sinks to the bottom of the ocean * Warm water rises to the surface. * Cold water will go south towards the Antarctic * Warm water will come back up to the Pacific * This conveyor belt helps regulate the amount of sea ice in polar regions.

There are 3 types of water withdrawal * Agricultural * Industrial * Municipal
Water Shortages * The rate of water consumption is growing twice as fast as population growth. * Water is a limited factor as it limits the amount of food that can be produced in a region.
Water Diversion * Groundwater is the largest source of freshwater in the world. * Freshwater is being diverted into many different purposes. * Environmental consequences from this diversion can be * Concentration of salts and minerals and pollutants may increase * Can reduce the habitat for fish and can impact feeding and spawning success * Temperature and oxygen levels can increase. * A reduction of the native populations of animals and plants.