HR: 0800h
AN: B51C-0607    [Abstracts]
TI: Differential Photosynthetic Responses of two Deciduous Shrub Species to Short and Long Term Snow Accumulation in the Arctic Tundra of Northern Alaska.
AU: * Pattison, R R
EM: anrrp@uaa.alaska.edu
AF: Environment and Natural Resource Institute, University of Alaska, Anchorage 707 A Street, Anchorage, AK 99501, United States
AU: Welker, J
EM: afjmw1@uaa.alaska.edu
AF: Environment and Natural Resource Institute, University of Alaska, Anchorage 707 A Street, Anchorage, AK 99501, United States
AU: Sveinbjornsson, B
EM: afbs@uaa.alaska.edu
AF: Environment and Natural Resource Institute, University of Alaska, Anchorage 707 A Street, Anchorage, AK 99501, United States
AU: Sveinbjornsson, B
EM: afbs@uaa.alaska.edu
AF: Department of Biological Sciences, University of Alaska 3211 Providence Drive, Anchorage, AK 99508, United States
AU: Sullivan, P F
EM: paddy@uaa.alaska.edu
AF: Environment and Natural Resource Institute, University of Alaska, Anchorage 707 A Street, Anchorage, AK 99501, United States
AU: Sullivan, P F
EM: paddy@uaa.alaska.edu
AF: Department of Biological Sciences, University of Alaska 3211 Providence Drive, Anchorage, AK 99508, United States
AB: Shrub abundance is increasing in many ecosystems in the arctic. This change is likely to have large scale implications on carbon, water and energy balances both at local and global scales. A proposed mechanism underlying increased shrub abundance is a positive feedback where shrubs increase snow accumulation which insulates soils during the winter and increases nitrogen mineralization in these nutrient limited ecosystems. The deciduous shrub Betula nana has been implicated as the primary driver of changes in snow accumulation. We examined the leaf level photosynthetic rates of B. nana and another deciduous shrub species Salix pulchra after short (1 winter) and long-term (12 winters) snow accumulation treatments. Our results indicate differential photosynthetic responses of the two shrub species with B. nana showing a greater increase in photosynthesis in response to long term snow increases but not following 1 year of snow addition. Salix did not exhibit significant increases in leaf level photosynthesis in response to short or long term increases in snow depth. Higher leaf- level carbon fixation by Betula may partially explain it's gradual dominance under deeper snow conditions in winter and may be associated with greater N availability and higher leaf N.
DE: 0476 Plant ecology (1851)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 1851 Plant ecology (0476)
SC: Biogeosciences [B]
MN: 2007 Fall Meeting