Transcript The Hydrosphere - NAU jan.ucc.nau.edu web server

Hydrosphere
• Only planet with
correct atmospheric
pressure and
temperature
to allow water to
Figure 2-11 (Merritts et al., 1998)
exist in all its phases
• 97% water held in ocean basins
• 2% water frozen
• Only 1 % water fresh*
Image ID: corp1893, NOAA Corps Collection
Location: Alaska Southeast
Photo Date: August 1991
Photographer: Commander John Bortniak, NOAA Corps
The Hydrologic Cycle
• Water continuously circulates from the ocean to the atmosphere to the land and
back to the ocean.
• Regardless of its physical form-solid,liquid, or vapor-every molecule of water
eventually moves through the hydrologic cycle.
Water sources for
Earth included
1) water from icy
comets,
2) volcanoes, and
3) minerals.
(Press and Siever, 1986)
Hydrosphere residence times
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Oceans = 3,100 years
Atmosphere = 9 days
Continents = 403 years
Rivers 12 - 20 days
• These residence times are significant for
evaluating environmental issues.
Water budget for the U.S.
• ~15.9 trillion
liters/day fall on the
U.S.
• 66% returned to
atmosphere by
evaporation and
transpiration
• 3% seeps into
groundwater
• 31% as runoff to
rivers and lakes
Water Reservoirs
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Rivers
Lakes
Wetlands
Groundwater
Oceans
“cryosphere” (glaciers)
Rivers: sources of flow
• Rain falling on
the surface of the
Earth may
infiltrate (to
groundwater),
runoff (to rivers),
or evaporate/
transpirate (to
atmosphere).
River discharge
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Amazon, South America
212,400 m3/s
La Plata, South America
79,300 m3/s
Congo, Africa
39,600 m3/s
Yangtze, Asia
21,800 m3/s
Brahmapututra, Asia
19,800 m3/s
Ganges, Asia
18,700 m3/s
Mississippi, North America
17,300 m3/s
• Colorado River, North Am.
300 m3/s
Large rivers of the U.S.
Rivers: Human influences
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Commerce
Transportation
Irrigation
Waste disposal
Dams diversions
Lakes
• Basins that collect water
• Location of basins defined by geologic
setting, presence of water based on climate
(local or regional)
• Most of the world’s freshwater resides in
lakes
Lakes: Human influences
• Pollution
• Water diversion
• Exotic species
Wetlands
• Wetlands are usually inundated by water during some
part of the year, are poorly drained, have low relief, and
have high soil moisture.
• Wetlands may appear
along coasts as swamps
or marshes (i.e. salt
marshes) or in the
continental interior as
marshes, wet
meadows, or prairie
potholes, or peat moss
bogs
http://www.epa.gov/owow/wetlands/
http://www.epa.gov/owow/wetlands/
Natural wetlands have distinct ecosystem functions
to which society can assign a “value.”
• nutrient storageremoval of fertilizing nutrients
helping farmers to attain compliance with water
quality targets
• accumulation of organic material for fuel or
agriculturestorage of carbon, source of peat
• filtering of solids from waterswastewater and
sewage treatment, trapping sediment
Natural wetlands have distinct ecosystem functions
to which society can assign a “value.”
• animal habitatsfishing, wildfowl hunting and
fish and shrimp hatcheries. In addition, Wetlands
are a home to a third of the nation’s threatened and
endangered species.
• plant habitatsforestry, agriculture
• regulating water outflowflood and erosion
protection
• all functionsrecreation, research, and education
Wetland losses in the U.S.
In the 1660’s, 220 million acres of wetlands were thought to
exist in the U.S. By 1980, only 103 million acres remained.
• Drainage
• Dredging
• Stream
channelization
• Diking, damming
• Tilling
• Logging
• Levees,
• Mining
•  nutrient levels
• Pollution
• Nonnative species
http://www.epa.gov/owow/wetlands/
Groundwater
• Water enters the ground as excess surface water
• Water then seeps downward due to gravity and the porous
nature of soil, rock, and sediment
• Water ultimately seeks it’s base level (usually sea level)
Groundwater Depletion
• Overdraft
• Subsidence
• Saltwater intrusion
Groundwater Pollution
• Contaminant transport
Environmental problems related
to water usually involve
problems with water quantity or
water quality.