Today is my last day at Kevo. Yesterday I had to say goodbye to the Petsikko Wetlands. We had a blast out there under a beautifully blue sky with enough cooling breeze to keep most of the bugs at bay. You just can't ask for more than that!
One of the things I have learned heaps about while out here is how important soil microbes are. Not only are they important for the ecological role they play – decomposing dead stuff – but I now understand that, at least from wetlands, they are responsible for emitting greenhouse gasses.
The Junior High School science textbooks I have used to support classroom learning barely mention soil microbes. As a result, I have decided to write up a hands-on "Litterbag Science" project as one of my contributions to the PolarTREC website lesson plan section.
Litterbag science is apparently well known and used, and after Kim showed me the basics today, I think this represents a fantastic opportunity for students to gain some field science practice while learning about the work of soil microbes.
Basic Tools
One of the reasons I want to learn more about litterbag science is that you really do not need any fancy or expensive equipment. Kim showed me a litterbag shortcut: use teabags in place of gathering and drying your own leaf litter.
The basic tools needed for litterbag science are teabags in synthetic bags, a trowel, a ruler, and a compass (which we forgot to bring).
With stockings and a drying oven you can make your own litterbags, but Kim noted that teabags are often used as litterbags since they tend to be very uniform. You can also bury several different types of teabags in one spot to give the soil microbes a wider range (chemically) of organic material to work on. We used red tea and green tea for our practice experiment.
Notes on the Procedure:
Simple teabag litterbags, well labeled for easy identification after a few months of decomposition.
Besides labeling the teabags well so you will know what you have retrieved when you uncover a mixed blob in a few months, you need to record the mass of each bag.
Record the mass of each teabag as accurately and precisely as you can before burying it.
You use a trowel to open a slot for the litterbags. You want to avoid digging so as to disturb the roots and soil microbial community as little a possible. Students can decide what variables they want to test: are the litterbags to be buried at different depths? Are they to be buried in association with different tree and/or groundcover species? What about burial at different elevations, or perhaps in sites that have differing soil moisture content?
Record the depth at which you bury your litterbags. I recommend using a measuring device that is opaque, not clear!
Once the litterbags are at the depth you want, gently push the soil back to cover the bags.
Kim and I buried our litterbags all at the same depth, but at slightly different elevations and under different trees species. Next time she is at Petsikko, Kim will also bury a second set of litterbags in much wetter conditions.
Practice Experiment
It was fun to set up this little practice experiment. I will be burying some litterbags around my area when I return to Fairbanks, and Kim and I will compare results after a few months. I can see how the process will be easily adaptable for classrooms of students. I will do some reading on the procedure, and write something up that others can use. Check the PolarTREC website later if you are interested in downloading the lesson plan!
For now, I am tickled that I still have a little science connection to Kevo. Today we buried the litterbags in a location that is off the main thoroughfares and will not likely be disturbed. The area also happens to be just off my favorite section of Kevo trail overlooking the lake!
The litterbags we buried are in the mixed Scots pine/mountain birch forest of Kevo.