1. June 3, 2015
Homework:
Are you caught up with your notebook? Check table of contents.
I can…predict how carbon pool size changes over time in a fire.
Did you complete the Lab #24 Summarizing Questions from yesterday, if not complete this (next slide)
Prediction… How would a forest fire contribute to carbon fluxes?
Find the following resources at the resource table that you will need today:
Fire Handout
Ecosystem Disturbances Worksheet

2. Lab #24 Summarizing Results
What patterns do we see in the total number of carbon atoms (triangles)? Why does this happen?
What pattern do you notice in the atoms in the organic/inorganic pools? Why does this happen?
What events cause carbon pools to change over time?

3. Read Fire Handout and Answer Questions in Journal
Explain how fires benefit ecosystems.
How does fire help maintain the longleaf pine ecosystem?
Describe how a change in fire frequency and severity could impact longleaf pine savannas. What would be the consequences to this ecosystem?
Describe how carbon moves through different pools when a fire burns. How do theses fluxes change in a low vs. high severity fire?
Why has Smokey the Bear’s message changed over time?

4. One example of a disturbance to an ecosystem is fire.
Introduce the task for this Activity: Fire as a disturbance in a prairie.
Show students Slide 2 of the Lesson 4.3 Ecosystem Disturbances Presentation. Tell students that in the handout they just read, they were learning about fire in forests and savannas. Now we will talk about forests in a prairie ecosystem.
Image Credit: Hannah Miller, Michigan State University

5. Your Task: On your worksheet, graph how the organic carbon pool in a prairie changes over time.
Number of Carbon Units
1200
= Total carbon units in prairie organic matter
1000
800
= Carbon units in above ground organic matter
600
= Carbon units in root
organic matter
400
Display Slide 3 of the presentation. Tell students that it is their job to follow along on their worksheet to graph how the organic matter pool in a prairie changes over time.
Give each student one copy of Lesson 4.3 Ecosystem Disturbances Worksheet.
200
Year 1
Year 2
Year 3
Year 4
Year 5
Note – this is a simplified model of organic matter in a prairie ecosystem before and after a burn. Many factors have not been accounted for, including root growth that can be stimulated by fire, how often this prairie is burned, the maturity of the prairie when the burn takes place, and the time of year the organic matter is measured.

6. Graphing organic matter in a prairie ecosystem
Year 1: The prairie is rebuilding its organic matter after a fire a few years ago. There are 700 carbon units below ground (in the roots) and 150 carbon units above ground (in the shoots and leaves).
Year 2: FIRE! The carbon in the prairie’s above-ground organic matter return to the atmosphere as CO2, and the fire triggers roots growth. There are now only 5 carbon units above ground, and 700 carbon units below ground.
Have students complete the worksheet with help from the information in the presentation.
Display Slide 4 of the presentation and have students complete the graph on their worksheet with the information provided. Check to see if students understand how to mark the three data points for each year on their graph.
Squares = carbon units in the roots
Circles = carbon units in the above ground organic matter
Triangles = total carbon units (roots + above ground organic matter)
Use Slides 4-6 to have students complete the graph on their worksheet.
Image Credit: Hannah Miller, Michigan State University

7. Year 3: After the fire, the prairie regrows
Year 3: After the fire, the prairie regrows. The plants further develop their root systems and regrow above the ground. Now there are 800 carbon units in the roots and 200 carbon units in the above ground organic matter.
Year 4: The prairie continues to grow and maintains 800 carbon units in the roots and 200 carbon units in the shoots.
Use Slides 4-6 to have students complete the graph on their worksheet.
Image Credit: Hannah Miller, Michigan State University

8. Year 5: Prairie is fully grown, with 80% of its organic matter in its root system, and 20% of its organic matter above ground. There are a total of 1000 carbon units of organic matter now.
Use Slides 4-6 to have students complete the graph on their worksheet.
Image Credit: Hannah Miller, Michigan State University

9. Fire as a “Flux”
A “flux” is the movement of carbon atoms from one pool to another over time.
Think: What fluxes occurred in the 5 years of the prairie’s life on your graph?
Pair: Find a partner
Share: Explain the different fluxes you see on your graph. Tell your partner how carbon atoms are moving from the organic matter pool in the prairie plants to the CO2 pool in the atmosphere.
Think Pair Share.
Display Slide 7 of the presentation. Have students think, pair, and share their ideas to answer the question about the fluxes that they observed in the prairie over 5 years. Look to see if they identify the flux that occurred as a result of the fire, and how they describe changes to the organic carbon pool and the CO2 pool.
Image Credit: Hannah Miller, Michigan State University

10. Complete Worksheet – ready for a stamp tomorrow
Brainstorm about how different disturbances might cause similar or different changes to an ecosystem.
Display Slide 8 of the presentation. Ask students to brainstorm: “What other events besides fire might cause an ecosystem to change?”