1. CYCLING OF PHOSPHORUS ATOMS

2. Energy Flow & Nutrient Cycling
Life on Earth depends upon one–way flow of high–quality energy from sun & cycling of crucial elements.

3. Nitrogen and Phosphorus…These elements are essential to function and productivity of ecological systems.

4. Importance of Phosphorus (P)
Like nitrogen, phosphorus (P) is an essential part of the process of photosynthesis.
Involved in the formation of all oils, sugars, starches, etc.
Helps with the transformation of solar energy into chemical energy; proper plant maturation; withstanding stress.

5. Importance of Phosphorus (P)
Effects rapid growth.
Encourages blooming and root growth.
Phosphorus originates from rocks

6. Phosphorus Cycle (P)

7. Layers of the Earth Hydrosphere- water layer. Liquid, Ice, Vapor.
Lithosphere- Earth’s crust and upper mantle.
- Fossil fuels, minerals, soil chemicals.
Biosphere- biotic & abiotic factors.

8. Phosphorous Cycle Atmosphere Biosphere Lithosphere Hydrosphere
Never enters the atmosphere
Atmosphere
Biosphere
Absorption
Waste & Decomposition
Weathering & Erosion
Lithosphere
Hydrosphere
Absorption
Sedimentation

9. 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

10. Background
The phosphorus cycle does not have a gas phase, but small amounts of phosphoric acid rise into the atmosphere, contributing to acidic precipitation.

11. Background
The water, carbon, and sulfur cycles all include at least one phase in which the element is in its gaseous state.
The largest reservoir of phosphorus is in sedimentary rock.

13. The Cycle

14. Description of Cycle Simplest of the cycles
Phosphorus has only one form – phosphate
Always part of an organism, dissolved in water, or in the form of rock

15. Description of Cycle
Phosphorus enters environment from rocks or deposits
Apatite is the phosphate rock where phosphate is available
Weathering and erosion releases phosphate ions that are soluble in water

17. Description, cont.
Phosphate then acts as fertilizers or nutrients for land plants
It gets incorporated into molecules essential for life like ATP, adenosine triphosphate – this is important in storage and use of energy

18. Description, cont. Phosphate is in backbone of DNA and RNA
When animals and plants die, phosphates will return to the soils or oceans again during decay

19. Description, cont.
Phosphorus cycles through plants and animals much faster than it does through rocks and sediments..
A lot of phosphate goes into the water from erosion and leaching
Water plants use this phosphate as nutrients

20. Description, cont.
Phosphate is the limiting agent in growth of plants and algae
If there is a lack of phosphate, plants grow slowly or are stunted
If too much, excess growth may occur

21. Description, cont.
Phosphate in water is precipitated from water as ion phosphate (insoluble)
Phosphate in shallow sediment may be recycled into water
In deep sediment in water, it is available as part of as part of rock formations for cycle to repeat

22. Description, cont.
After that, phosphorus will end up in sediments or rock formations again, remaining there for millions of years.
Eventually, phosphorus is released again through weathering and the cycle starts over.

23. Major components of aquatic ecosystems.
Fig. 4–11

24. Major components of terrestrial ecosystems.
Fig. 4–12

26. Human Influences on Cycle
Human influences on phosphate cycle mostly comes from introduction & use of commercial synthetic fertilizers.
Phosphate obtained by mining at certain deposits of calcium phosphate called apatite.

27. Influences cont.
Phosphate rock and sulfuric acid are combined to make a fertilizer called “super phosphate.”
There are many negative effects of using this fertilizer.

28. Influences cont.
A lot of the fertilizer is lost through the water run-off because plants aren’t able to use up all of it.
Eventually the wasted phosphate in the water is precipitated as it settles at the bottom of the body of water.

29. The Phosphorus Cycle Crop Atmospheric harvest deposition Animal
Component
Input to soil
Loss from soil
The Phosphorus Cycle
Crop
harvest
Atmospheric
deposition
Animal
manures
and biosolids
Mineral
fertilizers
Plant
residues
Runoff and
erosion
Primary
minerals
(apatite)
Organic phosphorus
Microbial
Plant residue
Humus
Plant
uptake
Mineral
surfaces
(clays, Fe and
Al oxides,
carbonates)
Weathering
Adsorption
Immobilization
Mineralization
Soil solution
phosphorus
HPO4-2
H2PO4-1
Desorption
Secondary
compounds
(CaP, FeP, MnP, AlP)
Dissolution
Leaching
(usually minor)
Precipitation

30. Phosphorus Cycle

31. The Phosphorus Cycle
How and in what form(s) does phosphorus enter and leave the cycle?
How do the roles of autotrophs and heterotrophs differ?
What are the human impacts on the cycle?