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2008 Alaska Park Science Symposium
October 14, 2008
The Impacts of Hillslope Thermokarst Formation on Soils Structure in the Noatak National Preserve
Jeremy B. Jones1, William B. Bowden2, Michael N. Gooseff3, Andrew W. Balser4, Amanda J. Rinehart5, Aurora Bouchier6
1Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA, Phone 907-474-7972, ffjbj@uaf.edu
2Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT, 05405, USA
3Department of Civil and Environmental Engineering, Pennsylvania State University, University Park, PA, 16802, USA
4Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
5Institute of Arctic Biology, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA
6Department of Geology and Geologic Engineering, Colorado School of Mines, Golden, CO, 80401, USA
Hillslope thermokarst formation is a widespread phenomenon in arctic Alaska and results in the catastrophic collapse of soil structure and alters the route of soil and ground water flow through landscapes. We investigated the impacts of hillslope thermokarst formation on soil organic carbon and nutrient storage, and the chemistry of waters flowing from thermokarsts. In 2007, a series of hillslope thermokarst formations and associated water tracks were sampled in the Kelly River region of the Noatak National Preserve. From each thermokarst, soil cores and water samples were collected from soil within and outside of the formation. The loss of soil structure due to thermokarst formation leads to a loss of soil organic matter storage and appears to increase the hydrologic export of dissolved organic matter and nutrients. The storage of carbon and nitrogen in soil was substantially lower in hillslope thermokarst formations compared with reference, non-disturbed cores. In contrast, water flowing from thermokarsts is enriched in dissolved organic matter, inorganic nutrients and other solutes compared with water tracks flowing over intact tundra. With climatic warming and thawing of permafrost, hillslope thermokarst formation will likely increase. Following thermokarst formation, soil structure is fundamentally altered, which, in turn, will affect vegetation structure in arctic national parks and preserves.
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