Review of Carbon, Nitrogen and Phosphorus Cycles

1
Review of Carbon, Nitrogen and Phosphorus Cycles
2
The Carbon Cycle
3
Carbon Moves From

• Atmosphere to plants
• (C02 pulled from air to use in photosynthesis)
• Plants to animals
• (animals eat plants or other animals)
• Plants and animals to soils
• (decaying bodies release carbon into the soil)
• Living things to atmosphere
• (as you exhale, release CO2)

4
Concerns for Humans

• CO2 is a greenhouse gas that traps heat in the
  atmosphere.
• Burning fossil fuels has added 5.5 billion tons
  per year of carbon to the atmosphere (a 30
  increase over the past 150 years)
• The increased Carbon is causing the planet to
  become warmer.

5
The Nitrogen Cycle

• 80 of Nitrogen is in the atomosphere
• (it is not in a form that humans can use needs
  to be broken down by lightning, fire or bacteria)
• Animals get nitrogen to make amino acids by
  eating plants
• (when animals/plants die, decompose and return
  nitrogen to soil)

6
Concerns for Humans

• The use of nitrogen rich fertilizers, causes too
  much nitrogen to be added to waterways via
  runoff.
• Animal wastes associated with farming add more
  nitrogen to soil and water.
• Burning fossil fuels fixes nitrogen from the air.
• High concentrations of nitrogen in the water
  causes algae blooms toxic to fish and
  shellfish.

7
The Phosphorus Cycle

• No atmosphere connection. Phosphorus added by
  animal waste, runoff and rock erosion.
• (Plants hydrolyze the phosphorus animals eat the
  plants. Decaying plants and animals and animal
  wastes return phosphorus to the soil.)

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Concerns for Humans

• Phosphorus run off leads to eutrophication
• Eutrophication a process whereby water bodies,
  such as lakes, estuaries, or slow-moving streams
  receive excess nutrients that stimulate excessive
  plant growth (algae and nuisance plants weeds).
  This enhanced plant growth reduces dissolved
  oxygen in the water when dead plant material
  decomposes and can cause other organisms to die.