HR: 0800h
AN: C21C-1136    [Abstracts]
TI: Towards a Reassessment of High Arctic Soil Organic Carbon Storage: Northwest Greenland Case Study
AU: * Horwath, J L
EM: horwath@u.washington.edu
AF: University of Washington, Department of Earth and Space Sciences Box 351310, Seattle, WA 98195
AU: Sletten, R S
EM: sletten@u.washington.edu
AF: University of Washington, Department of Earth and Space Sciences Box 351310, Seattle, WA 98195
AB: To quantify the potential release of terrestrial carbon from the High Arctic and its potential feedback to global climate change requires an accurate estimate of the soil organic carbon (SOC) storage. While it has been recognized that the Arctic (particularly the Low Arctic) contains substantial stores of SOC, there have been sparse or incomplete studies of SOC in the High Arctic. Results from a three-year study of soils in northwest Greenland indicate that previous reports substantially underestimated carbon storage in the High Arctic by more than an order of magnitude. Previous studies were based only on the upper 25 cm of soil and therefore cannot fully account for the pervasive cryogenic mixing in these soils that disrupts soil horizons and mixes substantial amounts of SOC to greater depths. Our three-year study was conducted on a 365 km² peninsula near Thule Air Base in northwest Greenland. Over 75 soil pits were excavated to the late June to early August thaw depth (20-96 cm range). SOC was determined for each soil horizon, weighted by the cross-sectional area, and summed over the depth of the soil pit to provide an estimate of SOC normalized to square meter surface area. The study sites traversed a diversity of bedrock, soils, vegetation, topography, relative surface ages, and patterned ground features that have varying amounts of carbon. Correlations of SOC with these parameters are being investigated to provide the background for generalizing these results to larger regions of the High Arctic. Our reassessment of High Arctic carbon stores in northwest Greenland provides more accurate estimates of SOC and can thereby better constrain models investigating the potential consequences of climate change and provide insight into geocryogenic soil mixing.
DE: 0704 Seasonally frozen ground
DE: 0710 Periglacial processes
DE: 0712 Cryosol
SC: Cryosphere [C]
MN: Fall Meeting 2005