THE PHOSPHORUS CYCLE

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THE PHOSPHORUS CYCLE
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WHAT IS THE PHOSPHORUS CYCLE?

• The phosphorus cycle, is the circulation of
  phosphorous among the rocks, soils, water, and
  plants and animals of the earth. Human beings and
  all other organisms must have phosphorus to
  live. In nature, most phosphorus occurs in
  phosphate rock, which contains phosphate ions
  combined with calcium, magnesium, chlorine, and
  fluorine.

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• It cannot be found in air in the gaseous . This
  is because phosphorous is usually liquid at
  normal temperatures pressures.
• This cycle is the slowest of the matter cycles.
• Phosphorus is most commonly found in rock
  formations and ocean sediments as phosphate
  salts. Phosphates are also limiting factors for
  plant-growth in marine ecosystems, because they
  are not very water-soluble.

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The process of the Phosphorous cycle

• ?The cycle basically starts out in the earths
  soil. The soil contains phosphate and when
  something grows out of the soil it should have
  phosphate as well.
• ?When the plants grow they are consumed by
  herbivore and omnivore animals
• ?The animals waste or the animals body when it
  dies becomes detritus.

• ?Detritus is non-living organic material. When
  the detritus goes deep into the soil,
  detritivores in the soil decompose and become the
  soils phosphate and the cycle repeats.

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• Another example of the phosphorus cycle is when
  rocks are created.
• The phosphate in the soil moves on and transfers
  its phosphate to the rocks underwater. When the
  uplifting of the rocks occurs it takes the
  phosphate along with it. After that the
  weathering of rocks occur and the rocks begin to
  break down into the soil and the phosphate in the
  rocks ends up in the soil again and the cycle
  repeats.

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Uplifting of rocks
Phosphates in organic compounds
Weathering of rock
Phosphates in rock
Animals
Plants
Runoff
Detritus
Phosphates in soil (inorganic)
Phosphates in solution
Decomposition
Detritivores in soil
Precipitated (solid) phosphates
Rock
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? All these examples of phosphates are inorganic
(white boxes). However, the Phosphorus Cycle is
also organic (yellow boxes). ?Not all
phosphates in the runoff make it to the water
others sink into the soil. These inorganic
phosphates are transformed into organic ones by
plants, which are in turn eaten by animals. ?
The dead animals, retain their internal
phosphorus stores and detritivores (scavengers
which feed on dead plants and animals or their
waste) change the organic phosphates back to
inorganic ones.
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HOW DO HUMANS INTERFERE WITH THE PHOSPHORUS CYCLE?

• Cutting and burning of tropical rain forests
  affects the phosphorus cycle. As the forest is
  cut and/or burned, nutrients originally stored in
  plants and rocks are quickly washed away by heavy
  rains, causing the land to become unproductive.

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• ? Agricultural runoff provides much of the
  phosphate found in waterways. Crops often cannot
  absorb all of the fertilizer in the soils,
  causing excess fertilizer runoff and increasing
  phosphate levels in rivers and other bodies of
  water. The phosphate in the water is eventually
  precipitated as sediments at the bottom of the
  body of water. In certain lakes and ponds this
  may be re-dissolved and recycled as a problem
  nutrient.

• Animal wastes or manure may also be applied to
  the land as fertilizer. If misapplied on frozen
  ground during the winter, much of it may lost as
  run-off during the spring thaw. In certain area
  very large feed lots of animals, may result in
  excessive run-off of phosphate and nitrate into
  streams.

CRAP
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• Another human cause of artificial eutrophication
  is run-off from mines. Mining in areas where rock
  is rich in phosphorus minerals can create dust
  that is blown by wind into nearby water systems.

• A major problem with the use of phosphorus in
  fertilizers is the process of artificial
  eutrophication. Eutrophication is a large
  increase in the primary productivity of a lake.
  Eutrophication can be harmful to the natural
  balance of a lake and result in massive death of
  fish and other animals as dissolved oxygen levels
  are depleted from the water.

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