For the Instructor
These student materials complement the Critical Zone Science Instructor Materials. If you would like your students to have access to the student materials, we suggest you either point them at the Student Version which omits the framing pages with information designed for faculty (and this box). Or you can download these pages in several formats that you can include in your course website or local Learning Managment System. Learn more about using, modifying, and sharing InTeGrate teaching materials.Unit 6.2: Biogeochemical Cycling Examples - Phosphorus and Eutrophication
Introduction
In this unit you will explore critical zone function and dynamics as they relate to nutrient cycling in agricultural systems and nutrient pollution into aquatic systems. This unit is generally subdivided into three sections: (1) nutrient pollution (2) agricultural importance and (3) critical zone function and dynamics in relation to nutrient cycling. Important present day topics of food production, clean water, nutrient pollution, and sustainable agriculture are examined using a CZ lens in which you will:
- examine general geochemical concepts, processes, theory and specifically the phosphorus and nitrogen cycles
- evaluate the impact the critical zone has on clean water
- use data to explain the role the critical zone plays in agriculture and eutrophication, and how the two interact
- explain the differences in land-use on nutrient cycling and CZ functions
Unit 6.2: Biogeochemical Cycling - Phosphorus and Eutrophication
Part 1 - Nutrient Pollution
Pre-class
- Carpenter, S. R. (2008). Phosphorus control is critical to mitigating eutrophication. Proceedings of the National Academy of Sciences. 105(32), 11039-11040 and answer these questions Carpenter Reading Questions - Student Copy (Microsoft Word 2007 (.docx) 13kB Dec25 16).
In-class
Nutrient Pollution and the Dead Zone Discussion
- You will recap your answers to Carpenter, S. R. (2008) with your peers, and discuss as a class, the impacts of both phosphorus and nitrogen. Then the topic of nutrient pollution will be explored using slides, videos, and class discussion.
Agricultural Influences and Impacts
- You will examine the relationship between soil and our everyday lives by reading an article from Science magazine and answering questions related to the readings.
- Save Our Soils Questions (Microsoft Word 2007 (.docx) 14kB Dec25 16).
- Your group will be given a case study looking at the use of a specific best management practice in nutrient pollution reduction that you will summarize for the rest of the class. Reminder that this is a good opportunity to think about best management practices that could be explored in your final CZO project, as your proposed CZO should consider scale and services provided by the critical zone.
Reflection
- Reflect on what you learned, questions you have, and what you're confused about with respect to today's lecture and activities.
Homework
- Read two articles pertaining to dead zone size, both dealing with historical dead zone size and predictions regarding future dead zone size. In addition, you will have to find primary data to backup claims in the articles.
- Handout of assignment & articles Dead Zone Homework Assignment (Microsoft Word 2007 (.docx) 15kB Feb2 17).
Part 2 - Carbon, Nitrogen, and Phosphorus
In-class
Cycling of Nitrogen, Carbon & Phosphorous (N, C, P)
- Today's class will start with some questions to answer about dead zones to make sure the last class period and homework assignments are making sense and to set the stage for today's class. Then in groups you will create a global cycling schematic for P and N based on the article provided. This will help as you explore critical zone C, N, and P cycling via a powerpoint presentation.
Ted Talk and Rebuttal Activity
- As a class you'll watch a Ted Talk and then in groups you'll read and discuss a response to the talk. In addition to the content of both you should also consider the role and importance of science communication.
Critical zone functions and dynamics
- Class discussion of primary literature regarding the change in agricultural soil carbon, N and P cycling, and mineral P and aquatic P limitation. Then you will examine how weathering impacts different elements differently and the role that parent material plays on soil and water characteristics.
Reflection
- Reflect on what you learned, questions you have, and what you're confused about with respect to today's lecture and activities.
Homework
- Each of the homework options listed below allow you to consider the biogeochemical issues relating to water quality. Your instructor will provide guidance on which homework option to complete.
- Option A: Listen to the following podcast and write a one-page summary.
- Podcast: Diving Deeper Podcast.
- Option B: Produce a case study showing how specific biogeochemical processes have influenced the amount and quality of water and soil in a specific region or area.
- Activity 6.3 - Homework Activity (Summative Unit Assessment): Nutrient Challenge.
- Handout: Transformative Strategies for Reducing Excess Nutrients in Waterways (Microsoft Word 2007 (.docx) 23kB Dec25 16).
- Rubric: Rubric for Transformative Assignment (Microsoft Word 2007 (.docx) 16kB Dec25 16).
Additional Resources
- Answer keys will be distributed in class.
- Nutrient Pollution Websites:
- http://www.nsf.gov/news/special_reports/deadzones/
- http://water.epa.gov/type/watersheds/named/msbasin/upload/hypoxia_reassessment_508.pdf
- https://oceanservice.noaa.gov/hazards/hypoxia/
- http://water.epa.gov/type/watersheds/named/msbasin/nutrient_strategies.cfm
- http://oceanservice.noaa.gov/education/tutorial_pollution/welcome.html
- CZO websites:
- Alexander, R.B., R.A. Smith, G.E. Schwarz, E.W. Boyer, J.V. Nolan, and J.W. Brakebill. 2008. Differences in phosphorus and nitrogen delivery to the Gulf of Mexico from the Missississippi River Basin. Environ. Sci. Technol. 42(3):822-830 doi:10.1021/es0716103
- Banwart. 2011. Save our soils. Nature. 474: 151-152.
- Buss H.L., Mathur R., White A.F., and Brantley S.L. 2010. Phosphorus cycling in deep saprolite, Luquillo Mountains, Puerto Rico. Chemical Geology. DOI: 10.1016/j.chemgeo.2009.08.001
- Filippelli, G. M. 2002. The global phosphorus cycle. Reviews in Mineralogy and Geochemistry 48: 391–425.
- Carpenter, S.R., N.R. Caraco, D.L. Corell, R.W. Howarth, A.N. Sharpley, and V.H. Smith. 1998. Nonpoint source pollution of surface waters with phosphorus and nitrogen. Ecological Applications. 8(3):559-568.