Quantitative Skills > Teaching Resources > Activities > Global Phosphorus Cycle

Global Phosphorus Cycle

Vassar College
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This activity was selected for the On the Cutting Edge Exemplary Teaching Collection

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This page first made public: Jul 15, 2005


This exercise guides students through creating and modifying a STELLA model of the global phosphorus cycle to test the behavior of phosphorus reservoirs in a number of scenarios. Students build a steady state system and then modify it to explore anthropogenic changes to the system, including the addition of phosphorus-rich fertilizers to the land surface and the shut down of ocean circulation due to global climate change. Other scenarios include an increase in plate tectonic rates, increased insoluble weathering due to glaciation, and changes in the planet's plant populations. The exercise includes the use of STELLA and Fortran 90 code.

Learning Goals

The P cycle exercise has several purposes:

Context for Use

This activity was developed for a class introducing dynamical systems modeling to upper level undergraduate students. The author introduces a series of weekly modeling projects with this exercise.

Teaching Notes and Tips

Instructor Notes (Acrobat (PDF) 60kB Apr10 06)

Teaching Materials

Phosphorus_cycle_exercises_for_students.pdf (Acrobat (PDF) 18kB Jun7 05)
Documented_P_Cycle.stm ( 294kB Jun7 05)
phosphorus.f90 ( 5kB Jun7 05)


PCycle_Exercises_Answer_key.pdf (Acrobat (PDF) 259kB Jun7 05)
assignment_assessment_1.pdf (Acrobat (PDF) 5kB Jun7 05)

References and Resources

The following are readings for the exercise.

Chameides, W.L., and Perdue, E.M., 1997, Biogeochemical Cycles: A ComputerInteractive Study of Earth System Science and Global Change, New York: Oxford University Press, p. 97-107 (Chp. 5, The Global Phosphorous Cycle).

Jahnke, R.A., 1992, The Phosphorus Cycle, in Butcher, S.S., Charlson, R.J., Orians, G.H., and Wolfe, G.V. (eds.), Global Biogeochemical Cycles, New York: Academic Press, p. 301-315.

Lerman, A., Mackenzie, F.T., and Garrels, R.M., 1975, Modeling of Geochemical Cycles: Phosphorus as an Example, Geological Society of America Memoir 142, p. 205-218.

Contact the Author

Please contact the author with questions or suggestions.

Controlled Vocabulary Terms

Subject: Geoscience:Atmospheric Science, Biology, Environmental Science:Ecosystems:Biogeochemical cycling, Geoscience:Atmospheric Science:Climatology , Geoscience:Geology
Resource Type: Computer Applications, Activities:Classroom Activity
Special Interest: Quantitative, Computer-Based
Grade Level: College Upper (15-16)
Quantitative Skills: Models and Modeling
Ready for Use: Ready to Use
Topics: Earth surface, Climate, Atmosphere, Biosphere
Theme: Teach the Earth:Course Topics:Biogeoscience, Environmental Science, Teach the Earth:Incorporating Societal Issues:Climate Change, Teach the Earth:Course Topics:Atmospheric Science

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