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Abstracts
SEARCH Open Science Meeting
October 27, 2003
Seattle, Washington, USA
Coupling of Carbon and Water in High Arctic Ecosystems
Jeffrey M. Welker1, Ronald Sletten2, Bernard Hallet3, Josh Schimel4, Birgit Hagadorn5, Heidi Steltzer6, Paddy Sullivan7, Jennifer Horwath8
1Natural Resource Ecology Laboratory, Colorado State University, NESB Building, Fort Collins, CO, 80525, USA, Phone 970-491-1796, Fax 970-491-1965, jwelker@nrel.colostate.edu
2Quaternary Research Center, University of Washington, Box 351360, Seattle, WA, 98195-1360, USA, Phone 206-543-0571, Fax 206-543-3836, sletten@u.washington.edu
3Quaternary Research Center, University of Washington, Box 351360, Seattle, WA, 98195-1360, USA, Phone 206-685-2409, Fax 206-543-3836, hallet@u.washington.edu
4Biological Sciences, University of California-Santa Barbara, 507 Mesa Road, Santa Barbara, CA, 93106, USA, Phone 805-893-7688, Fax 805-893-4724, Schimel@lifesci.lscf.ucsb.edu
5Quartenary Research Center, University of Washington, Box 351360, Seattle, WA, USA, Phone 206-543-4571, Fax 206-543-3836, hagedorn@u.washington.edu
6Natural Resource Ecology Laboratory, Colorado State University, Fort Collins, CO, 80523-1499, USA, Phone 970-491-5724, Fax 970-491-1965, steltzer@lamar.colostate.edu
7Natural Resource Ecology Laboratory, Colorado State University, B218 NESB, Fort Collins, CO, 80523, USA, Phone 970-491-5630, Fax 970-491-1965, paddy@nrel.colostate.edu
8Quaternary Research Center, University of Washington, Box 351360, Seattle, WA, USA, Phone 206-543-1166, Fax 206-543-3836, horwath@u.washington.edu
We are quantifying the coupling of the carbon and water cycles and the interacting physical, chemical and biological (PCB) processes that control C exchange between cold, dry terrestrial ecosystems and the atmosphere. We are focusing on cold, dry ecosystems because: (1) understanding of carbon and water interrelationships and net C exchange is only rudimentary for this extreme environment, making it impossible to predict the vulnerability of this ecosystem to the expected anthropogenically-exacerbated warming; (2) these tundra systems are sufficiently simple allowing the quantification of all key components and the development of a system behavior conceptual model and (3) the vital role of unfrozen water in this cold, dry environment underlies the importance of thresholds (e.g. 0°C is a distinct threshold for water availability) and highly nonlinear interactions between PCB processes. Our discoveries will contribute to the understanding and the quantification of global carbon and water cycling, as well as to the understanding of extreme habitats on Earth.
We are focusing on three levels of biocomplexity. First, we are quantify the seasonal changes in the coupling of C and water at the leaf and ecosystem scales using ), in situ isotopic (δ13C and δ18O) approaches. Second, are evaluating and quantify how the seasonal patterns of physical (soil temperature and soil water), chemical (soil solution and weathering) and biological (microbial and vegetation) processes interact to regulate the dynamics of net C exchange. Third, we will use a biogeochemical model (TEM) to investigate net CO2 exchange and the complex PCB interactions under current climates and a range of likely future climate change scenarios and integrate these with arctic and global carbon budget estimates. Our program will be based on articulating the complexities of carbon and water coupling under current conditions, but also on the responses of the biological, chemical and physical processes and interactions in response to field manipulations of winter and summer precipitation (increases) and warming (+2 and +4°C). This experimental approach is the means by which we can evaluate the interactions and nonlinearities of carbon and water coupling, net carbon exchange and PCB processes.
Abstract Categories: Changes on Land
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