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These materials are part of a collection of classroom-tested modules and courses developed by InTeGrate. The materials engage students in understanding the earth system as it intertwines with key societal issues. The collection is freely available and ready to be adapted by undergraduate educators across a range of courses including: general education or majors courses in Earth-focused disciplines such as geoscience or environmental science, social science, engineering, and other sciences, as well as courses for interdisciplinary programs.
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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 4.2: Carbon Budgets

Introduction

The purpose of this unit is to explore, compare, contrast and interpret carbon fluxes from the Ameriflux network to better appreciate the critical factors that account for the different timing and magnitude of fluxes among these sites. This module will help you complete your semester-long project by introducing you to critical baseline data collection and data bases related to carbon budgets.

The primary data set for this activity is the Amerflux network database, which spans over 150 sites throughout the Americas. Each data set is uniformly formatted and can contain up to 45 fields of meteorological and flux data collected from various eddy correlation tower instruments. In this unit, you will:

  • use a carbon cycle diagram to discuss the different pathways carbon moves at a watershed scale
  • contrast global and biome-specific carbon budgets to better understand watershed-scale processes
  • relate carbon flux data collected at various scales to understand the regional exchange of carbon at an Ameriflux site
  • explore and visualize carbon flux data from the Ameriflux database
  • use carbon flux data from the Ameriflux database to support a simple hypothesis relating carbon flux to driving environmental variables

Unit 4.2: Carbon Budgets

Part 1 - Carbon Flux

Pre-class In-class

Examining Annual Carbon Flux Activity

  • The purpose of this exercise is to compare and contrast data from four eddy correlation measurement sites to discover and think about the causal or physical relationships among these variables. Examine the four graphs in Table 4.2.1 (resources) and look for critical relationships between the parameters.

Lecture

  • The purpose of these slides is to tie the motivation for monitoring CO2 back to the bigger issue of global climate change and to highlight some of the key understandings we have of the carbon cycle and what the flows of carbon are at the global scale. The slides also start to introduce some of the plant physiological factors that affect the magnitude of the carbon flux.
    • Lecture Notes, Carbon Cycle and Budgets, Printable (6/pg) Note Set (Acrobat (PDF) 1.5MB Feb25 17).

Carbon Flux Graphing Activity

  • The goal here is to work with typically archived carbon flux data. For convenience, we have selected the Ameriflux network (which has limited overlap with the CZO network). In class you will start exploring the Ameriflux database and examine metadata that will be crucial to understanding the data record.

Homework

  • This homework is more fully described in the Student Worksheet (above). In order to give you broader exposure to a high quality Carbon flux dataset and because of network‐to-network inconsistencies in the CZO data set, we will focus our initial data manipulations on the excellent Ameriflux network with over 150 sites throughout the Americas. Once you have experience with this data set, it is fairly easy to address similar questions with the CZO data set. As a challenge, look at a different data set than the one covered in class and produce two labeled graphs demonstrating that you can visualize this data set using Excel or Matlab.

Part 2 - Carbon Flux Hypothesis

Pre-class

In-class

Review and Discussion

  • Discuss the previous class activities. This discussion and supporting material highlights eddy correlation which is the source of some of the CZO data we are dealing with.
    • Support for previous assignment: Example Excel Graphs (PowerPoint 2007 (.pptx) 3MB Dec23 16).
    • Eddy Correlation Lecture Notes, Printable (6/pg) Note Set (Acrobat (PDF) 384kB Feb25 17).
  • Please review the following source material

Carbon Flux Hypothesis Activity

  • The purpose of this activity is to connect physical factors that might affect ecosystem productivity with the flux data available from the CZO or Ameriflux databases. One way to get started is to think about the four biomes we looked at originally (Rockies Ponderosa Forest, High Plains Grassland, Appalachian Deciduous Forest, and Canadian Pine Forest) and consider what factors control plant growth.

Homework

  • Form a simple hypothesis regarding factors affecting the CO2 flux and support it using Ameriflux data.

Additional Resources

Activities

Sources of Data

Background Materials

Example data sets - Ameriflux Data (averaged and plotted by Washburne for InTeGrate, 2013 from data downloaded from Ameriflux website)

Table 4.2.1: Here are some data plots to give you an idea about flux magnitudes
Site Flux Tower Graphs

Full Set of 15 carbon Flux Graphs (9/pg)

CarbonFluxSet (Acrobat (PDF) 458kB Sep21 13)

Sa1: LBA Tapajos Mature Tropical Forest

Sa3: LBA Tapajos Logged Tropical Forest

Sa12005 (Acrobat (PDF) 33kB Sep21 13)

Sa32003 (Acrobat (PDF) 32kB Sep21 13)

NR1: Niwot Ridge Evergreen Alpine, CO

NS5: Manitoba Evergreen Forest, CN

Fuf: Flagstaff Evergreen Forest, AZ

NR12007 (Acrobat (PDF) 35kB Sep21 13)

NS52007 (Acrobat (PDF) 35kB Sep24 13)

Fuf2007 (Acrobat (PDF) 37kB Sep21 13)

SP1: Austin Cary Pine, FL

ME2: Metolius Interm. Pine, OR

KS2: Kennedy Space Ctr Scrub Oak, FL

SP12006 (Acrobat (PDF) 34kB Sep21 13)

ME22007 (Acrobat (PDF) 35kB Sep21 13)

KS22006 (Acrobat (PDF) 36kB Sep21 13)

MMS: Morgan Monroe Decid. Forest, IN

WBW: Walker Branch Decid. Forest, TN

Ha1: Harvard Decid. Forest, MA

MMS2005 (Acrobat (PDF) 35kB Sep21 13)

WBW1999 (Acrobat (PDF) 48kB Sep21 13)

Ha12006 (Acrobat (PDF) 36kB Sep21 13)

Var: Vaira Ranch Grassland, CA

Wkg: WG Kendall Grassland, AZ


Var2007 (Acrobat (PDF) 34kB Sep21 13)

Wkg2007 (Acrobat (PDF) 36kB Sep21 13)

IB2: Fermi Prairie, IL

Wlr: Walnut River grasslands, KS

IB22006 (Acrobat (PDF) 35kB Sep21 13)

Wlr2003 (Acrobat (PDF) 35kB Sep21 13)

These materials are part of a collection of classroom-tested modules and courses developed by InTeGrate. The materials engage students in understanding the earth system as it intertwines with key societal issues. The collection is freely available and ready to be adapted by undergraduate educators across a range of courses including: general education or majors courses in Earth-focused disciplines such as geoscience or environmental science, social science, engineering, and other sciences, as well as courses for interdisciplinary programs.
Explore the Collection »