Applying the Rules to Environmental Science: Biogeochemical Cycles

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Applying the Rules to Environmental
ScienceBiogeochemical Cycles
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EarthMatter does not come and go
So matter is constantly recycled on Earth
Earth is a closed system to matter
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Biogeochemical CyclesReservoirs Pathways
Atmosphere
Biosphere
Lithosphere
Hydrosphere
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Some Major Cycles of Matter

• Water Cycle
• Rock Cycle
• Chemical Cycles
• Carbon
• Nitrogen
• Phosphorous
• Sulfur

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Carbon Cycle
Atmosphere
Biosphere
Lithosphere
Hydrosphere
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Carbon Cycle Reservoirs
Atmosphere
1x ( 7.3x1017 grams carbon)
Biosphere
3x
55x
35,000x
Lithosphere
Hydrosphere
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Carbon Cycle
Atmosphere
Biosphere
Lithosphere
Hydrosphere
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Carbon TransferBiosphere Atmosphere
Photosynthesis (Atmosphere to Biosphere)
Carbon Dioxide Water Sunlight --gt Sugar
Oxygen
Respiration (Biosphere to Atmosphere)
Sugar Oxygen --gt Carbon Dioxide Water Energy
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Carbon Cycle
Atmosphere
Biosphere
Lithosphere
Hydrosphere
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Carbon Cycle
Human Impacts
Atmosphere
Biosphere
Net Effect Increase in Carbon in Atmosphere
Lithosphere
Hydrosphere
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Atmospheric Carbon Dioxide
northern winter
northern summer
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Impact
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Nitrogen Cycle
Atmosphere
Denitification bacteria
Biosphere

• Nitrogen fixation
• bacteria
• lightning

Absorption
Waste Decomposition
Erosion
Lithosphere
Hydrosphere
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Nitrogen-Fixing Bacteria in Root Nodules
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Nitrogen Cycle
Human Impacts
Atmosphere
Biosphere
Net Effect Increase in Nitrogen in water soil

• Nitrogen fixation
• industrial (fertilizer)
• combustion

Increased Erosion
Lithosphere
Hydrosphere
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Phosphorous Cycle
Never enters the atmosphere
Atmosphere
Biosphere
Absorption
Waste Decomposition
Weathering Erosion
Lithosphere
Hydrosphere
Absorption
Sedimentation
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Phosphorous Cycle
Human Impacts
Biosphere
Net Effect Increase in phosphorous in water
algal blooms Depletion in soils
Mining, use (fertilizer, detergent, etc.)
increased runoff
Lithosphere
Hydrosphere
More Phos. for organisms
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ImpactEutrophication
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ImpactRed Tide
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Sulfur Cycle
Bacteria Absorption
Atmosphere
Bacteria Release
Biosphere
Volcanoes Weathering
Absorption
Precipitation
Waste Decomposition
Weathering
Evaporation
Sedimentation
Lithosphere
Hydrosphere
Absorption
Deep Sea Vents
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Sulfur Cycle
Human Impacts
Atmosphere
Biosphere
Net Effect Increase in atmosphere (health
effects) and acid rain
Precipitation Acid Rain
Burning Fossil Fuels
Lithosphere
Hydrosphere
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Applying the Rules to Environmental
ScienceFood Webs
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EarthEarth constantly gains loses energy
Heat
Earth is a Open System to Energy
Sunlight
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Life is a struggle of an immense number of
organisms, weighing next to nothing, for a small
amount of energy.
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Producers( Autotrophs)
Energy enters the system
Tall grass prairie
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Producers
Chlorophyll
Photosynthesis
Carbon Dioxide Water Sunlight --gt Sugar
Oxygen
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Producers
Chemosynthesis
Hydrogen Sulfide Carbon Dioxide Water
Oxygen Geothermal Heat --gt Sugar Sulfuric Acid
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Consumers --gt Heterotrophs
Primary Consumers - eat producers (Herbivores) Se
condary Consumers - eat primary
consumers (Carnivores) Tertiary Consumers - eat
secondary consumers (Carnivores
Omnivores) Decomposers - break down dead organisms
Called Trophic (Feeding) Levels Represent the
flow of energy (food)
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Called Trophic (Feeding) LevelsRepresent the
flow of energy (food)
Sun
Flow of Energy
Primary Consumer
Secondary Consumer
Tertiary Consumer
Producer
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Forms aFood Chain
What happens if we kill off all the mice?
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Food Webs
What happens if we kill off all the crab eater
seals?
Food webs are more stable than food chains.
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Food Webs
What happens if we kill off all the crab eater
seals?
Food webs are more stable than food chains.
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Lessons

1. Food webs are more stable than food chains
2. The produces are the key to the entire food web
3. Life is rough at the top

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Energy Trophic Levels
Sun
Flow of Energy
Primary Consumer
Secondary Consumer
Tertiary Consumer
Producer
1000units
100units
10units
1units
900 lost
90 lost
9 lost
About 90 loss each step
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Energy Units Measured asBiomass
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Energy Units Measured asBiomass
Energy captured and turned into biomass by all
producers is called Net Primary Productivity
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For example
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Why does diet mater?
If each person required 10 g/m2 food per day
This ecosystem could feed
1 person on all carnivores
4 people on herbivores
80 people on plants
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Applying the Rules to Environmental
ScienceBioconcentration
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Bioconcentrationup the Trophic Pyramid
Energy degrades
but matter does not
Toxin (e.g. heavy metals)
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ExampleDDT
High concentrations of DDT weakens egg shells in
fish-eating birds chicks die