Today’s Journal
Dr. Tamara Harms came to Dawson today! My students were thrilled to get to learn from her and interact with a real researcher. Tamara talked with the students about what she does and why she spends her life studying carbon, nitrogen and phosphorous. Then she introduced them to the project we will be working on in the Arctic.
Dr. Harms brought an infra-red gas analyzer, which detects the CO2 flux , so we could look deeper into soil respiration. Prior to Tamara’s visit, I review the carbon cycle and asked my students to set up mini experiments to test soil respiration.
Dr. Harms describing how the infra-red gas analyzer works to detect CO2 flux
My students remembered that atmospheric concentration of CO2 is approximately 390ppm, yet in our classroom the concentration was already upwards of 500ppm. To begin, Dr. Harms had a student breath into inflow tubes of the instrument, as shown below.
A student blowing into the infra-red gas analyzer. The CO2 flux of his breath was about 900ppm.
We placed in the inflow tubes into each plastic bag of soil and then students watched the CO2 flux on the palm pilot. Students tried different soil types, such as dry soil from our schoolyard, compost, decomposing llama scat and horse manure. Some groups added treatments to the soil such as sugar water or nutrients or tried altering the temperature of the soil.
Students testing CO2 flux from their bag of soil
The largest carbon flux for the day came from the decomposed llama scat with added nutrients. My students will be summarizing their results and drawing conclusions soon,but in general they observed that added carbon, sugar, nurtients and heat all cause the activity of the soil microbes to increase, thus increasing the respiration.
Dr. Harms also shipped down some active layer and permafrost soil cores. The students touched, smelled and observed these cores. You can see in the photo below that the kids were enjoying themselves!
Students enjoying investigating tundra soil cores
It was pretty neat to see the permafrost core once most of the ice had melted out. It gave the students a good visual on what will happen as permafrost thaws.
Permafrost soil core with much of the ice melted after half a day out of the freezer.
Unfortunately, we only had one class period per class. The kids came back the next day asking lots of questions and wanting to test more soil samples! Overall it was a great way to bring the carbon cycle alive in my classroom and to expose the kids to soil respiration first hand. My students send their thanks (as do I)!!
Question to Ponder
Dr. Harms wanted to pose this question to my students: What happens to the carbon that is not respired?
Me and Dr. Tamara Harms in my classroom