LRES M.S. Thesis Defense: Ethan Wologo
- Tuesday, May 7, 2019 at 2:00pm
- Animal Biosciences Building, 134 - view map
The Effects of Permafrost Thaw and Geologic Substrate on Dissolved Organic Carbon Mobilization and Transformations in Arctic Streams
Permafrost landscapes exhibit unique hydrology that is linked both chemically and physically to nutrient cycling and geochemical processes. Permafrost thaw is expected to result in a positive feedback to global atmospheric carbon loads through carbon release. To address the clear and pressing need to better understand hydrologic pathways in permafrost landscapes in the face of global change, I used two approaches to investigate carbon export in the arctic:(1) Experimental additions of biolabile carbon (acetate) and inorganic nutrients (N and P) to stream water, to explore effects on dissolved organic matter (DOM) decomposition in stream water from seven permafrost regions; and(2) Field observation of U and Sr isotope ratios and dissolved organic carbon (DOC) concentrations in streams influenced by increasing groundwater-surface water connection, as a function of recent permafrost thaw associated with fire and human activity, mediated by substrate texture (loess vs. rocky colluvium).
It is likely that these signals will continue to transform as the arctic warms, with greatest resilience of ground ice in loess-blanketed areas not subject to disturbance or thermal erosion by groundwater inflows.
- Department of Land Resources and Environmental Sciences