HR: 10:20h
AN: C32A-01    [Abstracts]
TI: Carbon Dioxide Gas Exchange Through the Snowpack and Its Contribution to the Ecosystem Carbon Budget in a High-Elevation, Subalpine Forest
AU: * Seok, B
EM: brian.seok@colorado.edu
AF: Institute of Arctic and Alpine Research, University of Colorado 450 UCB, Boulder, CO 80309-0450, United States
AU: * Seok, B
EM: brian.seok@colorado.edu
AF: Department of Atmospheric and Oceanic Sciences, University of Colorado 311 UCB, Boulder, CO 80309-0311, United States
AU: Liptzin, D
EM: daniel.liptzin@colorado.edu
AF: Institute of Arctic and Alpine Research, University of Colorado 450 UCB, Boulder, CO 80309-0450, United States
AU: Liptzin, D
EM: daniel.liptzin@colorado.edu
AF: Ecology & Evolutionary Biology, University of Colorado 334 UCB, Boulder, CO 80309-0334, United States
AU: Chowanski, K
EM: kurt.chowanski@colorado.edu
AF: Institute of Arctic and Alpine Research, University of Colorado 450 UCB, Boulder, CO 80309-0450, United States
AU: Hueber, J
EM: jacques.hueber@colorado.edu
AF: Institute of Arctic and Alpine Research, University of Colorado 450 UCB, Boulder, CO 80309-0450, United States
AU: Williams, M
EM: mark.williams@colorado.edu
AF: Institute of Arctic and Alpine Research, University of Colorado 450 UCB, Boulder, CO 80309-0450, United States
AU: Williams, M
EM: mark.williams@colorado.edu
AF: Department of Geography, University of Colorado 260 UCB, Boulder, CO 80309-0260, United States
AU: Helmig, D
EM: detlev.helmig@colorado.edu
AF: Institute of Arctic and Alpine Research, University of Colorado 450 UCB, Boulder, CO 80309-0450, United States
AB: Snow cover significantly affects microbial activity in the soil underneath by influencing both respiration and soil nitrification and denitrification processes. Past studies have shown how this can alter ecosystem carbon budgets as climate change continues. In our project, we measured winter carbon flux from the soil through the snowpack near treeline at a 3345 m asl site in the Niwot Ridge Long-Term Ecological Research area in the Colorado Rocky Mountains for 3 winter seasons (2004 – 2006). Fick's law of diffusion was applied to calculate the carbon flux from measurements of gradients in gas concentrations and snowpack density. We also analyzed the influence of wind-pumping (or pressure-pumping) on carbon flux calculation, which Fick's law ignores. Generally, flux calculations using Fick's law without incorporating wind-pumping effects gave us an underestimate of the true carbon flux. We measured maximum snow depth at our study site to be 1.9 m in 2005 and 2.1 m in 2006. The total wintertime seasonal CO₂ loss was 8.89 mol m^-2 for 2004 and 7.48 mol m^-2 for 2005. These values are about 2 times larger than those observed at a lower elevation (3021 m asl) flux tower approximately 3 miles from our site (4.03 mol m^-2 from 2003 winter season), which is within a closed canopy forest dominated by subalpine fir, Engelmann spruce, and lodgepole pine.¹ This and similar research presented previously have been done in high altitude alpine regions. We are now continuing our work at the University of Michigan Biological Station Ameriflux site, which is a low elevation (219 m asl) lake-side region near Pellston, MI to further study the environmental factors that determine the CO₂ gas exchange through the snowpack. ¹ Monson, R. K., S. P. Burns, M. W. Williams, A. C. Delany, M. Weintraub, and D. A. Lipson (2006), The contribution of beneath-snow soil respiration to total ecosystem respiration in a high-elevation, subalpine forest, Global Biogeochem. Cycles, 20, GB3030, doi:10.1029/2005GB002684.
DE: 0428 Carbon cycling (4806)
DE: 0736 Snow (1827, 1863)
DE: 0793 Biogeochemistry (0412, 0414, 1615, 4805, 4912)
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
SC: Cryosphere [C]
MN: 2007 Fall Meeting