ENVS 291M: Advanced Readings in Biogeochemistry: Nutrient Cycling on Land

 

Instructor: Weixin Cheng (phone: 9-5317, email: wxcheng@ucsc.edu)

Location: NS2 431

Time: 9:30-11:30 am Wednesday, and TBA

 

This course consists of three parts: fundamental transformation and cycling of main nutrient elements (C, N, P, S, etc.) on land, research issues and questions in the field of terrestrial biogeochemistry, and some key methods.  Class activities include: (1) presentation of summary statements based on reading assignments; (2) discussion of theories, concepts, methodologies, and applications; (3) computer simulation and modeling of elemental cycles using STELLA; and (4) integration of scientific information by writing a review paper. 

 

Assignment:

Each participant is given an opportunity to choose a topic for a research review paper). The project has to focus on a particular area of biogeochemistry.  An outline of the proposed project is due by the third lecture.  Feedback from the instructor on the outline will be given back to each participant the following week. The anticipated length of the paper is 20-30 pages (double space, 12 point font, 1 inch margins) excluding figures and tables.  Each participant will be given a time period to present his or her project towards the end of this quarter.  Course evaluation will be given based on the quality of the paper and the presentation, and participation in the discussion during all lecture periods.

 

 

Outline

 

Lecture 1:  Introduction: The biosphere concept, biogeochemical cycles, and you review paper

 

Readings: Smil Vaclav. 2002. The Earth's Biosphere. Chapter 1: Evolution of the idea

 

 

Lecture-2: Using STELLA

 

 

Lecture 3-8: Carbon cycle on land

 

Readings for Lecture 2, 3,4, &5:

  1. Schlesinger’s book, Chapter 5.
  2. Chapin-Matson-Mooney’s book, chapters 5,6,7
  3. The set of papers related to “Nadelhoffer’s approach”
  4. The set of papers related to residence time
  5. The set of papers related to root turnover
  6. STELLA Manual

 

Exercise-1:

Build a Stella model using the information given in Figure 11.1 of Schlesinger's book, then estimate turnover time for the four C pools (atmosphere, plant biomass, soil, and ocean) using current rates of fluxes.  Run the model for 200 years using the time step of one year, and see what happens to the sizes of all four pools.  Do sensitivity analysis on changes of anthropogenic CO2 emission rate, soil respiration rate, and ocean uptake rate.  Make GPP of terrestrial ecosystems as a function of atmospheric CO2 concentration, soil respiration as a function of soil C pool, ocean uptake as a function of atmospheric CO2 concentration, then run the model for 200 years, what do you see?  If we have to "manage" the biosphere for the purpose of reducing the atmospheric CO2 concentration, what kinds of constraints do we have to think about? Can you set a priority list of research areas?

 

 

Lecture 9-12: Nitrogen Cycle on land

 

Readings:

  1. Schlesinger’s book, Chapter 6, 12.
  2. Chapin-Matson-Mooney’s book, chapters 9
  3. Jacobson et al. Chapter 12
  4. The set of papers from Weixin
  5. The set of papers from Mint?
  6. Likens G. E. and Bormman F. H. 1995. Biogeochistry of a Forested Ecosystem, 2nd edition

 

Exercise-2:

Based on your own understanding, build a model for C and N on a piece of land (forest, grassland or cropland). This model needs to include outside inputs, losses from the system, internal cycling among major pools (i.e., plants, soil, etc.).  Then simulate the effect of disturbances (e. i., fertilization, N-deposition, fire, etc.) on the modeled pools and fluxes.

 

 

Lecture 13-15: Cycling of other elements

 

Readings:

  1. Schlesinger’s book, Chapter 12, 13.
  2. Jacobson et al. Chapter 13,14,15
  3. The set of papers from Weixin
  4. Likens G. E. and Bormman F. H. 1995. Biogeochistry of a Forested Ecosystem, 2nd edition

 

Lecture 16: Integration and Synthesis

 

Lecture 17-20: Student’s project and discussion