# Carbon Dioxide Cycle Pool and Process Model Assignment

## Modeling Biogeochemical Cycles

This week you studied three biogeochemical cycles. Your assignment this week is to create a pool and process model of one of the three cycles.

### What are models?

Notably, models are simplifications of reality, used to help us understand a system, make predictions, etc… Your models may not have every nuance of the cycle you choose included in it, but it should be robust enough to be used to study the system and make predictions.

### Pool and Process Models

The type of model you are to use is a “pool and process” model, otherwise known as a “box and arrow” model. As you construct your model, you will draw a box for each pool in the cycle and draw an arrow for each process. Notably, the boxes/pools are where the material hangs out, and the arrows/processes show how the material moves from one pool to another. The diagrams in your textbook and lesson will be helpful…. and the video clip will be VERY helpful.

1. Choose one of the three cycles. Ultimately you will be responsible for all 3 cycles. I will be posting the best models of each cycle for everyone to view and study. (Be sure to watch the video clips first. I give LOTS of hints for these cycles in the clips… especially for carbon and nitrogen.)

2. Sketch your pool and process model on a piece of paper. The boxes represent the pools, and the arrows represent the processes. Be sure you label all the boxes and arrows.

Hints to get started:

• Important: For whichever cycle you choose, you absolutely should go back and study the diagrams in the this week’s third video clip.
• Hydrologic Cycle: Start with the ocean pool. (Draw a box and write the word ocean in it.) What process takes water from the ocean? Where does it go? (The water does not go directly from ocean pool to the cloud pool… there is another pool in-between). Then what? Work your way around the cycle. Use the diagrams and information in the video clip for ideas.
• Carbon Cycle: Start with the atmospheric CO2 pool. (Draw a box and write atmospheric CO2 in it.) Who uses CO2? Through what process? Then what? Notably, you’ll be drawing a small terrestrial cycle… and then the same sort of cycle within the oceans. Terrestrial plants get their CO2 from atmospheric CO2, and oceanic plants get there CO2 from CO2dissolved in the ocean. Use the diagrams and information in the video clip for ideas. Also, importantly, how do fossil fuels fit into this model?
• Nitrogen Cycle: Start with the atmospheric N2 pool. (Draw a box and write atmospheric N2 in it.) Then make an outer circle of pools and processes that have nothing to do with plants and animals. Then connect to plants and animals in an inner circle. What pool do plants get their nitrogen from. Use the diagrams in the lesson for ideas. Use the diagrams and information in the video clip for ideas.
• General: All boxes must have at least one arrow in and one arrow out. If there were no arrows out, all of that material would eventually end up in that pool!

3. Use the following online whiteboard (or something similar) to create a pdf file to submit. *

• Explore the website. Click on the pencil icon and notice you have 3 sizes of pen. The other icons with the pencil are for writing text and for erasing. Next click on the menu icon (looks like a gear). From here you can clear the screen or save your work. Practice using all the tools a bit.
• Draw the boxes and arrows of your model using the pencil icon.
• Choose the text tool to label each box and arrow.