HR: 1340h
AN: GC13A-0930    [Abstracts]
TI: Extreme drought and temperature conditions lead to variable response in Arctic tundra carbon flux
AU: * Laskowski, C A
EM: claskows@sciences.sdsue.edu
AF: San Diego State University, 5500 Campanile Dr, San Diego, CA 92182-4614, United States
AU: Oechel, W C
EM: oechel@sunstroke.sdsu.edu
AF: San Diego State University, 5500 Campanile Dr, San Diego, CA 92182-4614, United States
AB: Recent trends in the carbon flux of Alaskan Arctic tundra ecosystems show significant spatial variability across the Pan Arctic, from sink activity (wet sites indicative of the coastal climates) to neutral or slightly source activity (moist sites indicative of inland climates) over many years. The conditions during summer 2007 were significantly warmer, drier, and had increased available light than previous years. Both sites exhibited average temperatures >40% higher, total precipitation >60% lower, and available light >10% higher than average. At the cooler, coastal, wet sedge tundra site (Barrow), the ratio of sensible to latent heat flux increased 25%, and at the warmer, moist tussock tundra site (Atqasuk), nearly doubled. Although the microclimatological trends were similar between the sites, the carbon flux response was disparate. Increased temperature and decreased precipitation resulted in greater efflux from Atqasuk; however, the increased temperature and, surprisingly, decreased precipitation, resulted in increased photosynthetic activity at the Barrow site. The extreme conditions displayed in summer 2007 have also helped to parameterize the factors influencing carbon flux across the arctic landscape and will therefore increase the ability to understand the potential effects of future climate change.
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
DE: 1616 Climate variability (1635, 3305, 3309, 4215, 4513)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1637 Regional climate change
DE: 9315 Arctic region (0718, 4207)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting