Unit V Earth Systems

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Unit VEarth Systems Resources
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Water Resources

• Properties of Water
• 2 parts Hydrogen and 1 part Oxygen (H2O)
• Water is never completely pure in nature.
• Many substances water dissolves and causes water
  pollution
• Contents of Sea Water

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Hydrologic Cycle

• The same water has been recycled through the
  atmosphere since the earths beginning!
• Evaporation
• conversion of water into water vapor
• Condensation
• conversion of water vapor into water
• Precipitation
• water that falls to the Earth from the atmosphere

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Hydrologic Cycle

• Transpiration
• water loss by a plant through evaporation
• Respiration/Perspiration
• water loss by animals
• A drop of water could spend as little as 9 days
  in the atmosphere or as much as 40,000 years in
  the ocean before being recycled.

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Distribution of Water

• Ocean Water
• 97.5 of planets water
• Cover 75 of the planets surface
• Freshwater
• Remaining 3 divided between rivers, lakes,
  groundwater, aquifers
• greatest amount is in glaciers and polar ice
• only 0.5 is available freshwater

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Water Terminolgy

• Surface Water
• Precipitation that remains on the surface
• Runoff
• Movement of surface water to lakes, rivers, etc.
• Watershed (drainage basin)
• land drained by surface water
• Groundwater
• Freshwater stored underground
• Aquifer
• Underground caverns and porous layers of sand,
  gravel, rock that stores groundwater

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Aquifers
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Water Bodies

• Rivers
• Bodies of lotic water eventually emptying into
  oceans
• Nile is longest
• Amazon has greatest volume
• Lakes
• Bodies of lentic water surrounded by land
• Lake Superior is largest surface area
• Lake Baikal is biggest, oldest, deepest
• 1660 m deep
• Seas
• Smaller, at least partially enclosed areas of
  ocean or inland seawater
• Caspian Sea is largest enclosed sea
• Oceans
• Can you name all 5 oceans?

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Water Supply Issues

• 3 basic categories
• Too much water
• Too little water
• Poor quality/contamination of water
• Balanced water budgets have equal amounts of
  water coming in as going out in all locations.
• Situations Create Changes
• Unevenly Distributed Populations, seasonal
  factors, geography, politics, etc.

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Water Usage

• Water Uses
• World Uses
• Irrigation 65
• Energy 25
• Domestic Use 10

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Too Much Water!

• Flooding
• Both natural and human induced
• Removal of water-absorbing plants covering the
  soil
• Construction of building on floodplains

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Too Little Water

• Causes
• Geography/Climate
• Drought
• Overdrawing of resources
• Aquifer depletion
• Subsidence Sinkholes
• Saltwater Intrusion

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Problems in US

• Overall, US has plentiful water
• But shortages exist in many areas
• Geographic variations
• Seasonal variations

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Problems in US

• Water shortages in West and Southwest
• Water diversion projects
• Mono Lake (Eastern CA)
• Rivers and streams that once fed this lake are
  diverted to Los Angeles (275 mi away)
• Becoming highly saline
• Court ordered water diversion reduction
• Colorado River Basin
• Provides water for 27-million people
• Numerous dams for Hydropower
• Colorado River no longer reaches ocean

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Aquifer Depletion
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Aquifer Depletion

• Ogallala Aquifer
• Largest aquifer in the world
• Water withdrawn 9x faster than it is replaced

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Global Problems

• Water Budgets arent Balanced!
• Climate Change
• Affects type and distribution of precipitation
• Reduced snowfall impacts water downstream
• Sea level rises will cause saltwater intrusion
• Drinking Water
• Many developing countries have insufficient water
  to meet domestic needs

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Global Problems

• Population Growth
• Increase in population increases freshwater
  requirements
• Limits drinking water available
• Limits water for agriculture
• Sharing Water Resources
• Countries upstream discharge pollutants
• Water diversion has caused increases in salinity
• Potentially volatile situations
• Jordan and Nile Rivers
• Sharing is caring!

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Dams Reservoirs

• Benefits
• Ensures year-round supply of water
• Electricity generation
• Recreational activities

• Disadvantages
• Alters the ecosystem
• Reduces sediment load
• downstream

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Dams Reservoirs

• Disadvantages
• Impedes wildlife migration
• Fish ladders help but are only 50 effective at
  best

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Water Diversion Projects

• Water diverted to areas deficient
• California Aqueduct Project

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Other Water Supplies

• Desalinization
• Removal of salt from sea water
• Two methods
• Distillation
• Salt water is evaporated and water vapor
  condensed
• Reverse Osmosis
• Forcing salt water through a membrane filter
• Very Expensive
• Cloud Seeding
• Saturation of existing clouds to promote rain.
• Involves using dry ice or silver iodide
• Need existing clouds
• Introducing additional chemicals to environment

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Irrigation Issues

• Irrigation is largest user of water in the world.
• Gravity Flow
• 60 efficient
• Center Pivot
• 80 efficient

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Irrigation Issues

• Drip Irrigation
• 90-95 efficient

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Water Conservation

• Reduction of Industrial Water Waste
• Stricter laws provide incentive to conserve
• Water scarcity/rising costs encourages further
  recycling
• Reduction of Municipal Water Waste
• Water saving household fixtures
• Government incentives
• Gray water (aka reuse)
• Can be used for toilets, wash cars, water lawns

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Soil Resources

• Soil
• Controls the distribution of rainfall, regulates
  biological activity, and filters water, air, and
  nutrients.
• Soil Forming Factors
• Parent Material
• Time
• Climate
• Organisms
• Topography

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Soil

• Not just dirt!
• Mixture of eroded rock, minerals, inorganic
  nutrients, decaying organic matter, water, air,
  and living organisms.
• Soil Composition
• 45 mineral matter
• weathered rock
• 5 organic matter
• detritus
• 25water
• 25 air

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Soil
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Soil Layers

• Horizons
• soil forms in horizontal layers called horizons
• most plant roots are in the first two layers
• O Horizon
• surface litter layer
• freshly fallen and partially decomposed organic
  material
• leaves, twigs, fungus, animals, etc.
• A Horizon
• topsoil layer
• aka humus
• richest soil with dark coloring indicating high N
  content

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Soil Layers

• E Horizon
• strong leaching
• filtration
• B Horizon
• subsoil
• inorganic material
• sand, silt, clay, gravel
• C Horizon
• parent material
• pieces of rock
• Bedrock
• unweathered rock

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Soil Layers
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Soil Structure

• Clay
• smallest particle size
• retains water well, poor drainage
• Silt
• medium sized particles
• advantage of both sand and clay
• Sand
• relatively large particle size
• good aeration but poor water retention

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Soil Structure

• Gravel
• largest particle size
• no water retention but good water filtration
• Loam
• mixture of particles

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Soil Structure
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Soil Quality

• Porosity
• measure of the volume of pore spaces for air,
  water, and habitat
• Structure
• composition of particles determines a soils
  texture, how well it holds together, and if it
  will support roots
• Sorting
• how well defined the different particles of soil
  are
• Permeability
• speed of water transportation or drainage

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Soil Quality

• Conductivity
• how well it conducts electricity
• Nutrient Retention
• 6 primary nutrients
• N, P, K, Ca, Mg, S
• Stability
• ability to hold together and resist erosion
• pH
• Affects solubility of certain plant nutrients
• Optimum soil pH is 67, because nutrients are
  most available to plants at this pH

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Erosion

• Removes soil and ruins surface water where the
  soil is deposited.
• Causes
• primarily by wind and water
• also human activities
• logging, farming, ranching, construction
• Accelerated by poor agricultural practices

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Erosion

• Great Dust Bowl of 1930s
• severe drought
• 1930-1937
• poor agricultural practices
• no natural vegetative roots to
• hold soil in place

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Agricultural Degredation

• Soil Salinization
• Gradual accumulation of salt in the soil, usually
  due to improper irrigation techniques

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Agricultural Degredation

• Desertification
• Conversion of lands once productive into deserts.

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Increasing Crop Production

• Fertilizer Methods/Types
• Organic Fertilizers
• Animal manure
• improves soil structure, adds N, stimulates
  beneficial bacteria and fungi
• Green manure
• freshly cut vegetation clippings
• Increases organic material and humus
• Compost
• broken-down organic matter such as leaves, food
  wastes, wood
• Inorganic Fertilizers
• produced from various minerals
• account for ¼ of all crop yields

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Soil Conservation

• Erosion Reduction Methods
• Conservation Tillage Farming
• plowing the land with minimal disturbances
• Residues from previous years crops are left in
  place to prevent soil erosion
• Crop Rotation
• rotate between different crops over a period of
  years
• legume root nodules add N and reduce erosion
• Contour Farming
• plowing and planting crops in rows along the land
  rather than along the slope

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Soil Conservation

• Erosion Reduction Methods
• Terracing
• converting sloping agricultural land into
  terraced level steps
• Strip Cropping
• planting alternating strips of crops in order to
  trap water and soil particles

Strip Cropping
Terracing
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Soil Conservation

• Erosion Reduction Methods
• Alley Cropping/Agroforestry/Shelterbelts
• several crops are planted between rows of
  established trees and bushes.
• reduces wind erosion of soil

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Soil Conservation Laws

• Soil Conservation Act of 1935
• authorized formation of Soil Conservation
  Service, now called Natural Resource Conservation
  Service (NRCS)
• assess soil damage and develop BMPs to improve
  soil
• Food Security Act (Farm Bill) 1985
• farmers with highly erodible soil had to change
  their farming practices
• instituted Conservation Reserve Program
• pays farmers to stop farming highly erodible land

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Soil Conservation Laws

• 1872 Mining Law
• Forces government to sell public land leases to
  private investors at bargain prices
• Requires companies to return site to as good of
  condition, if not better, when completion of
  mining activity
• companies can (and have) abandon site or file for
  bankruptcy.
• leaves taxpayers with the clean-up bill
• some sites cost several million dollars to
  remediate

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Mineral Resources

• Minerals
• Naturally occurring elements or inorganic
  compounds found in Earths crust.
• Elements or compounds of elements that occur
  naturally in the Earths crust.
• non-renewable resources that can be extracted
  from known areas.
• known as reserves
• Rocks
• naturally formed aggregates of minerals
• Ores
• metal yielding rock

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Minerals

• Unevenly distributed throughout the world
• Discovery of new reserves
• Scientists (geologists) use a variety of
  instruments and measurements
• Aerial or satellite photography
• Seismographs
• Combine this with knowledge of how minerals are
  formed

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Mining

• Surface Mining
• extracts 90 of minerals in US (60 of coal)
• Open-Pit Mining
• Fe, Cu, sand stone
• Strip-Mining/Mountain Top Mining
• primarily for coal extraction
• Subsurface (Traditional) Mining
• less environmental damage
• less economical and more dangerous to miners

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Open Pit Mine
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Ore Processing

• Smelting
• process in which ore is melted at high temps to
  separate impurities from the molten metal

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Mining Effects

• Disturbs large area
• prone to erosion
• Uses large quantities of water
• must pump water out of mine to keep it dry
• Acid Mine Drainage (AMD)
• pollution caused when sulfuric acid and dissolved
  lead, arsenic or cadmium wash out of mines into
  nearby waterways

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Mining Effects

• Mill Tailings
• impurities in mined ore
• 80 or more of ore
• contain toxic materials
• Smelting plants
• emit large amounts of air pollutants
• requires vast amounts of energy

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Mining Restoration

• Goals
• prevent further degradation and erosion of land,
  eliminate local sources of toxins and make land
  productive for another purpose
• Creative Approaches
• Wetlands
• trap and filter pollutants before they get into
  streams
• initially expensive, but cost effective compared
  to using lime to decrease acidity
• Phytoremediation
• use of specific plants to absorb and accumulate
  toxic materials in soil

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Minerals

• Reserves
• mineral deposits that have been identified and
  are currently profitable to extract
• Highly developed countries
• rely on mineral deposits in developing countries
• many have exhausted their own supplies
• Developing countries
• governments lack financial resources to handle
  pollution
• acid mine drainage, air and water pollution

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Minerals
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Other Mineral Reserves

• Antarctica
• no substantial mineral deposits identified to
  date
• Antarctica Treaty of 1961
• limits activity to peaceful uses
• Madrid Protocol of 1990
• Moratorium on mineral exploration
• Deep Ocean
• may provide us with future supplies
• extracting minerals from seawater
• mining seafloor
• manganese nodules

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Manganese Nodule Deposits
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Mineral Conservation

• Reduce
• the amount of materials you use
• Reuse
• lunch boxes, sandwich bags, grocery bags, soda
  bottles, diapers
• Repair
• instead of replace

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Mineral Conservation

• Recycle
• Paper is the most recycled item

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Four Rs

• Recycle
• USE THE BINS!
• Paper is the most recycled item
• Primary/Closed Loop Recycling
• Waste is recycled into new products of same type
• old cans into new cans, old newspaper into new
  newspaper
• Secondary/Open Loop Recycling
• Convert waste materials into different products
• Newspapers into cellulose insulation
• Preconsumer/Internal Wastes
• wastes from manufacturing process
• Postconsumer/External Wastes
• wastes generated by the consumer

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