1. Ecosystems Unit Activity 3.1 Carbon Pools
Carbon: Transformations in Matter and Energy
Environmental Literacy Project Michigan State University
Ecosystems Unit Activity 3.1 Carbon Pools
Image Credit: Craig Douglas, Michigan State University

2. Introduction
In Lesson 1 you identified key features of ecosystems including:
Organic versus inorganic carbon
Groups of organisms that have similar roles (producers, herbivores, carnivores, decomposers)
Now we will put these ideas together to learn about how scientists keep track of carbon in ecosystems

3. Scientists group parts of ecosystems into “pools” of carbon
Image Credit: Craig Douglas, Michigan State University
Students are introduced to the idea of “pools” of carbon.
Use the animation on Slides 3-5 to show how scientists categorize organisms into particular “pools” of carbon. Use Slide 6 to help clarify what we mean by a soil carbon pool. Tell students that in the next few lessons, we will think about soil organic carbon as the location of both decomposers (bacteria and fungi) and also dead plants and animals waiting to decay. (Optional: have students think about the number of organisms they drew in each “pool” of carbon. Which pool of carbon do they think is the largest?

4. Carnivores organic carbon
Atmosphere CO2
Carnivores organic carbon
Herbivores organic carbon
Producers organic carbon
Soil
Organic Carbon
Image Credit: Craig Douglas, Michigan State University
Introduce the idea of “pools” of carbon (cont.)
ANIMATED SLIDE-- Use in ppt slide show mode

5. Organic Carbon Carnivores Organic Carbon Herbivores Atmosphere CO2
Image Credit: Craig Douglas, Michigan State University
Introduce the idea of “pools” of carbon (cont.)
The end result of the animation, but showing the pools up closer.
Organic Carbon
Soil
Organic Carbon
Producers

6. New Information Alert: What is soil organic carbon?
Image Credit: Craig Douglas, Michigan State University
Students are introduced to the idea of “pools” of carbon. (cont.)
Use Slide 6 to help clarify what we mean by a soil carbon pool. Tell students that in the next few lessons, we will think about soil organic carbon as the location of both decomposers (bacteria and fungi) and also dead plants and animals waiting to decay. (Optional: have students think about the number of organisms they drew in each “pool” of carbon. Which pool of carbon do they think is the largest?
It is a pool of carbon that contains:
Material from dead plants and animals waiting to decay (be eaten by decomposers) AND
Living decomposers.

7. The carbon pools can be classified into two main groups
Image Credit: Wendy Johnson, Michigan State University
Students classify the carbon pools as two main types: organic versus inorganic pools and discuss the connections.
Show slide 7 to discuss the two main types of carbon pools and ask the question “How are the carbon pools connected?” Have students share their ideas about how the carbon pools are connected. Students should be able to draw on previous learning in Carbon TIME Units to remember that plants transform inorganic carbon into organic molecules during photosynthesis and that all organisms rearrange organic molecules (biosynthesis) as well as transform organic molecules into inorganic CO2 during cellular respiration.
How are the carbon pools connected?

8. Plants use food in two ways
Materials for growth: Biosynthesis
Food
To Cells
Energy: Cellular respiration
Image Credit: Craig Douglas, Michigan State University
Students classify the carbon pools as two main types: organic versus inorganic pools and discuss the connections. (cont.)
Use slides 8-9 to begin to address the question of how the carbon pools are connected. Briefly review that organisms use their food in two ways: materials for growth (biosynthesis) and energy (cellular respiration).

9. Animals use food in two ways
Materials for growth: Biosynthesis
Food
Digestion
Energy: Cellular respiration
Image Credit: Craig Douglas, Michigan State University
Students classify the carbon pools as two main types: organic versus inorganic pools and discuss the connections. (cont.)
Use slides 8-9 to begin to address the question of how the carbon pools are connected. Briefly review that organisms use their food in two ways: materials for growth (biosynthesis) and energy (cellular respiration).

10. What happens to food that animals can’t digest?
Our digestive systems cannot break down some large organic molecules (such as fiber).
These molecules leave our bodies as feces.
Image Credit: Craig Douglas, Michigan State University
Students classify the carbon pools as two main types: organic versus inorganic pools and discuss the connections (cont)
Use Slide 10 to remind students that animals CANNOT digest some of the food that they eat (such as cellulose and other fiber molecules for humans). This food leaves the animals as feces.

11. Decomposers use food in two ways
Materials for growth: Biosynthesis
Food
Digestion
Energy: Cellular respiration
Image Credit: Craig Douglas, Michigan State University
Students classify the carbon pools as two main types: organic versus inorganic pools and discuss the connections (cont)
This food leaves the animals as feces. Use Slide 11 to discuss what happens to the feces after it leaves the cow’s body.
It is important that students recognize that living organisms do not create or destroy matter or energy but only transform them in biological processes.

12. The organic pools and inorganic pools are connected through biological processes
Photosynthesis – transforms CO2 to organic carbon
Biosynthesis & Digestion – rearrange organic carbon molecules into other organic carbon molecules
Feces & death – moves organic carbon to the soil pool
Cellular respiration – transforms organic carbon into inorganic carbon (CO2 in the air)
Students classify the carbon pools as two main types: organic versus inorganic pools and discuss the connections. (cont)
Use slide 12 to summarize the biological processes that connect carbon pools.

13. Scale
Just like in previous Carbon TIME Units we will be tracing matter and energy in the Ecosystems Unit. Now we will focus on tracing matter and energy across much larger scales. Therefore, the Three Questions that we are trying to answer are slightly different.
Explain that the Ecosystems Unit the focus will be on tracing matter and energy at the large scale.
Slides to emphasize that the Ecosystems Unit is focusing on a larger scale than previous organismal Units. The focus is still on tracing matter and energy, but the Three Questions are slightly different. You may wish to print the Lesson 1.2 Large Scale Three Questions Poster to post in the classroom and refer to throughout the Unit.

14. Large Scale Three Questions
Rules to Follow
The Carbon Pools Question:
Where are the carbon pools in our environment? How do the pools change size over time?
Atoms last forever.
For a carbon pool to change size, carbon atoms MUST move in or out of the pool.
The Carbon Movement Question:
Movement: How are carbon atoms cycling among pools?
Fluxes: At what rate are carbon atoms moving among pools?
Matter cycles within environmental systems.
Carbon-transforming processes move carbon atoms among pools. Carbon fluxes change the size of carbon pools.
The Energy Question:
How does energy flow through environmental systems?
Energy flows through environmental systems.
Carbon-transforming processes change energy from sunlight to chemical energy to motion and life processes to heat (eventually radiated into space).
Explain that the Ecosystems Unit the focus will be on tracing matter and energy at the large scale.
Slides to emphasize that the Ecosystems Unit is focusing on a larger scale than previous organismal Units. The focus is still on tracing matter and energy, but the Three Questions are slightly different. You may wish to print the Lesson 1.2 Large Scale Three Questions Poster to post in the classroom and refer to throughout the Unit.

15. How are pools and the biomass pyramid related?
Atmosphere CO2
Carnivores organic carbon
Herbivores organic carbon
Producers organic carbon
Soil
Organic Carbon