The Phosphorus Cycle

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The Phosphorus Cycle
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•       The symbol is P and the Lewis dot
  structure is

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•       Phosphorus is found in sedimentary rock,
  not in the atmosphere
•       (PO43-) found in HPO42- found in
  terrestrial rock formations and ocean sediments.
•       Essential in the production off DNA, fats
  in cell membranes off plants and animals, bones,
  teeth and shells.
•       Not dependent on bacterial action

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•       Not fount in any significant amount in the
  atmosphere.
•       Released from rock through weathering and
  acid rain. A slow process
•       Dissolved in soil water, and taken p by
  plant roots
•       Found in guano (waste of fish eating
  birds)

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Human impact

•       Mining large quantities for production of
  inorganic fertilizer
•       Clear cutting tropical areas for
  agriculture
• o    Decreases available phosphorus
• o    Little found in the soil
• o    When the vegetation is gone, P is washed away

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• o    Runoff of animal wastes from feedlots
• o    Stream runoff carries P to lakes and ponds
•       Increase growth of cyanobacteria
•       Green algae and aquatic plants
•       Increase causes sunlight to be blocked
•       Aerobic decomposers decrease O2 content in
  water
• Excess P ends up killing aquatic animals and
  plants

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