Observing the Earth - Chapter 11

What is the definition of freshwater?

water that is relatively pure, with few dissolved salts

How much water on Earth is freshwater?

2.5% of total water

How much of freshwater is stored in ice caps and glaciers?

69%

How much of freshwater is stored in ground water?

30%

How much of freshwater is surface water?

1%

How is water stored in the hydrosphere?

water is stored in oceans, lakes, rivers, and other bodies of water.

How is water stored in the atmosphere?

water is stored in water vapor, clouds, and precipitation

How is water stored in the geosphere?

water is stored underground as groundwater and in soil.

How is water stored in the biosphere?

water is stored inside living organisms, including plants, animals, and humans.

What is the water cycle?

also known as the hydrologic cycle, it’s the continuous circulation of water among the hydrosphere, the atmosphere, the biosphere, and the geosphere.

What is evaporation?

Moves water from water bodies into atmosphere, cooling

What is precipitation?

sinks into the ground or runs off into rivers to form lakes or enter oceans, warming

What is runoff?

surface water flowing to the sea in streams and rivers

What is transpiration?

water evaporates directly from plants

What is infiltration?

water seeps into the ground

What is a perennial stream?

a stream that maintains some flow even during dry seasons.

What is an intermittent stream?

a stream that does not maintain some flow all the time and may be dry for long periods.

What is meander stream?

loops caused by lateral erosion

What is point bar stream?

depositional area, usually on “inside” of meander loop

What is oxbow lake stream?

meander that gets pinched off

What is braided stream?

network of interconnected channels

How is meander formed?

by erosion and deposition create winding river bends.

How is point bar formed?

sediment deposits on the inside of a river bend

How is oxbow lake formed?

a meander gets cut off from the main river

What is braided stream?

sediment buildup causes a river to split into multiple channels

What is a drainage basin?

an area of land that feeds into a river or stream

contiguous land that is all “downhill”

What is the largest drainage basin in the United States?

Mississippi River Basin

What is a delta?

deposition into aqueous environment

What is a distributaries?

fan of water channels in a delta

What is a flood plain?

• that portion of a river valley adjacent to the channel

• it’s built upward by sediment deposited during floods and is covered by water during a flood.

What are the different sections of a delta?

• delta top

• delta front

• prodelta

Why are deltas important?

Deltas are important because they create land, support wildlife, and provide good foil for farming.

How are lakes formed in different conditions?

Lakes form when natural processes create low areas or block water flow, allowing water to collect.

What is an oligotrophic lake?

• a lake that is poorly nourished

• blue, clear water

• low productivity, limited organisms

What is a eutrophic lake?

• A lake that has high nutrient supply

• often littered, green water

• high productivity, dense vegetation/algae

What is eutrophication?

• Eutrophication occurs when excess nutrients, such as nitrogen and phosphorus, enter a body of water and cause excessive algae growth.

• When the algae die, bacteria decompose them and use up dissolved oxygen, which can cause fish and other aquatic organisms to die.

What are wetlands?

areas that are water soaked or flooded for all or part of the year

What are the three types of wetlands?

• swamps

• bogs

• marshes

What are the functions of wetlands?

• biologically productive

• degrade pollutants

• mitigate flooding

• carbon storage

• habitat

Why are wetlands disappearing?

Wetlands are lost by both human and natural causes.

What is a water table?

• the top surface of the zone of saturation

• the water table separates the zone of saturation from the zone of aeration above.

What is an aquifer?

a body of rock that can yield economically significant quantities of groundwater; should be both porous and permeable.

What is the confined aquifer?

• an inclined aquifer sandwiched between layers of permeable rock.

• typically, the water in the lower part of the aquifer is under pressure from the weight of water above.

What is artesian well?

• a well drilled into a confined aquifer, in which the water rises without pumping and in some cases flows to the surface

How is an artesian well formed?

It forms when groundwater is trapped under pressure between impermeable rock layers, causing water to rise naturally when a well is drilled into the aquifer.

What is a non-confined aquifer?

It’s an underground water-bearing layer whose upper boundary is the water table and is open to the atmosphere through permeable soil and rock.