Editor’s note: The following post is from guest blogger Clara Deck (’17) about her research experience this summer with an internship at one of the world’s most prominent laboratories. She is working on an important climate change project involving the carbon budget of permafrost. Last summer Clara completed a dendrochronology climate project in Wooster with Dr. Greg Wiles.
This summer I am working as a research intern at Argonne National Laboratory in Illinois as part of the ten week Student Undergraduate Laboratory Internship (SULI) program. The laboratory occupies 1500 acres located just north of Chicago and is a Department of Energy (DOE) facility. I have the privilege of joining Dr. Julie Jastrow and her terrestrial ecology research team on a project focused on organic carbon stocks in permafrost across Alaska. Soils serve as the largest terrestrial carbon reservoir, containing more than two times the amount of carbon found in the atmosphere.
About 25% of land mass in the northern hemisphere is dominated by permafrost soils. The long term goal of this project is to improve estimates of the total quantity of C contained in permafrost, as findings to-date are immensely variable. This is important because soil carbon will be affected by environmental change, especially in high latitude regions.
Field sampling targets features known as ice wedge polygons, which form similarly to mud cracks, but then fill with ice. The soil within these polygons is characterized by substantial cryoturbation, or mixing, due to freeze-thaw processes.
A trench like this is dug across a polygon, in order to sample from each distinguishable layer across an entire transect. This summer, I am performing fractionation procedures on these samples, which means separating the soil into different size components. The fractions will then be analyzed for carbon content. I will then use GIMP Image Manipulation Software to convey C density data in a cross sectional image of the polygon.
These diagrams illustrate the progression from a field sketch to a digital image showing C density in a polygon cross section. Ice wedge polygons adhere to large scale patterns across the landscape, so data from each polygon has upscaling potential for larger models. Further studies will include analysis of the carbon decomposability and the depth to which permafrost will thaw with predicted temperature rise.
I am excited to be at Argonne conducting research so closely related to modern climate change, and will be continuing these studies throughout the year for my Senior Independent Study. Thanks for reading!
What a great experience! It’s amazing how geologists get a better understanding of the system by examining spatial variations in composition. It’s very similar to our approach in our research on subglacial volcanics. Looks like you’re having a productive and fun summer research experience!
Could someone tell us the scale on that diagram (feet? meters?) and describe what features in the trench are being mapped, to be assayed for carbon type/content?
Are these mats of frozen plant material being dated, too, so that we will know how fast the permafrost accumulated in the past, and how quickly it might be degraded in the future, evolving carbon dioxide, methane, and water vapor into the (formerly) pristine Arctic atmosphere?
If it’s old enough at the base, can we use these trenches to map the ebb and flow of the boreal forests with glacial advance and retreat?
Bill, I apologize for leaving out the scale on the diagram, it is in meters. The mapped features represent soil horizons that have been deformed and mixed by cryoturbation. I am not aware of any dating, but there are studies in progress involving the susceptibility of this carbon to degradation. Factors involved are the thaw depth and hydrologic conditions during warming. I hope to look further into that aspect during the upcoming school year! I imagine that the ongoing cryoturbation processes would make it difficult to use the trenches as a chronological tool, but I’m not sure!
You might be interested in my experience in 2009 with Early Paleozoic “cryokarst” in Russia:
What a cool experience Dr. Wilson! I had no idea there were such old deposits, thank you for sharing!
Thanks for the added info, Clara, and good luck with your project!
Mark, I’m not too certain about that Russian cryokarst…. Looks like an interpretation boosted by too much vodka.
Interesting technique with the images and GIMP – look award to learning how it is done when you return.
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