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 Cyles and Feedback Loops I 
   Cycles and Feedback Loops 
 
 
Some Feedback Loops 
  Gaia as a Feedback Loop  
  The Earth  itself is a material cycle  
 Over time the earth acheives a balance which is disrupted by
 random catastrophe  
Exponential use of resources represents a "short-term" random catastrophe
for ecosystems as this disrupts the natural resource cycles.   The system
can not recover on such a short timescale.
 Radiation and heat balance in a spherical 
 Cow
 Cow  
 Carbon Cycle   
 Active Pools: 
  -  Atmosphere: 58,000  
  
-  Ocean Surface Layers: 43,000 
  
-  Ocean Deep Layers:  2,900,000 
Organic Carbon:
   -  Land organisms:  38,000
   
-  Decaying Organic Matter:  58,000
   
-  Marine Organisms:  830
  
-   Decaying Organic Matter Oceans: 250,000
 Storage Pools: 
As Carbonates:
  
-   Carbonate sediments: 1,700,000,000
 
As Organic Carbon:
 EXCHANGES: 
 
 -  Atmosphere   Ocean Surface: 7--8 years 
 
-  Ocean:  Surface   Depth: 1000 years 
 
-  Biological Fixation: 2100 per year (5 % of Terrestrial Organic Carbon) 
 
-  Fossil Fuel Combustion Addition: 420 per year 
-  Diagensis Return to Fossil Fuel Reservoir = 84 units per year 
 
  
Nitrogen Cycle:
 Active Pools:  
As Organic Nitrogen: 
  -  Land Organisms: 870
  
-  Marine Organisms: 69
   
-  Decaying Organic Matter:  120,000
 
As Inorganic Nitrogen
 -   Soils 10,000
  
-  Ocean Sediments 7,100
 
Storage Pools: In solution 
  -  Atmosphere: 270,000,000
  
-  Oceans: 1,400,000
As Rocks:
   -  crustal rocks: 1,000,000,000
 
EXCHANGES: 
 -  Biological Fixation Land: 3.9 units per year  
 
-  Biological Fixation Ocean: 0.74 units per year  
 
-  Atmospheric Fixation: 0.55 units per year 
 
-  Denitrification: Land 1.6; Ocean 2.9 
 
-  Industrial Fixation 3.2 (fertilizer) 
  
-  Eutrophication: reduced oxygen in water; algae thrives,
shellfish die 
 
 
 
 
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