HR: 0800h
AN: B51C-0608    [Abstracts]
TI: Effects of Deeper Snow on Ecosystem CO2 Fluxes in Tussock Tundra in Northern Alaska
AU: * Taneva, L
EM: lina.taneva@gmail.com
AF: University of Alaska Anchorage, Environment and Natural Resources Institute 707 A Street, Anchorage, AK 99501, United States
AU: Sullivan, P F
EM: paddy@uaa.alaska.edu
AF: University of Alaska Anchorage, Department of Biological Sciences, Anchorage, AK 99508, United States
AU: Sveinbjornsson, B
EM: afbs@uaa.alaska.edu
AF: University of Alaska Anchorage, Department of Biological Sciences, Anchorage, AK 99508, United States
AU: Welker, J M
EM: afjmw1@uaa.alaska.edu
AF: University of Alaska Anchorage, Environment and Natural Resources Institute 707 A Street, Anchorage, AK 99501, United States
AB: Climate warming in northern latitudes is projected to lead to increased precipitation and, therefore, increased snow depth in arctic ecosystems. Deeper snow in winter can affect these ecosystems by leading to warmer soils, shorter growing seasons, and increased water availability to plants after snow melt, with subsequent implications to ecosystem biogeochemical cycling. Increases in snow depth in the arctic have been reported to lead to changes in plant community composition and, particularly, increases in shrub abundance in tundra ecosystems. Because of the confounded effects of greater snow depth on arctic ecosystems, it is unclear what the mechanisms underlying observed shrub cover changes are. In this study, we investigated the differential effects of greater snow depth on ecosystem CO₂ exchange in tussock tundra near Toolik Lake, Alaska. We measured CO₂ uptake and ecosystem respiration throughout the growing season after the first winter of snow depth manipulation and compared these results to CO₂ exchange in plots under long-term (14 years) snow depth increase. Our initial findings indicate that long-term increases in snow result in greater relative increases in respiration as opposed to ecosystem photosynthesis, leading to greater net CO₂ efflux. However, in the first year of snow additions, these differences were not observed, nor were there any differential effects of winter warming only, or winter warming with added water on CO₂ exchange.
DE: 4806 Carbon cycling (0428)
DE: 4815 Ecosystems, structure, dynamics, and modeling (0439)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting