HR: 1330h
AN: B32B-0393    [PDF]
TI: Plants Dominate Initial Sequestration of Excess Nitrogen in Alpine Tundra
AU: * Holland, K J
EM: keri.holland@colorado.edu
AF: University of Colorado, INSTAAR 1560 30th Street, CB450, Boulder, CO 80309 United States
AU: Townsend, A R
EM: alan.townsend@colorado.edu
AF: University of Colorado, INSTAAR 1560 30th Street, CB450, Boulder, CO 80309 United States
AU: Bowman, W
EM: william.bowman@colorado.edu
AF: University of Colorado, INSTAAR 1560 30th Street, CB450, Boulder, CO 80309 United States
AU: Seastedt, T
EM: timothy.seastedt@colorado.edu
AF: University of Colorado, INSTAAR 1560 30th Street, CB450, Boulder, CO 80309 United States
AB: Despite recent interest in understanding the effects of nitrogen (N) deposition on alpine ecosystems, we lack key mechanistic understanding of what controls N retention and loss in these systems and how these processes will change with chronic N deposition. Research from forested ecosystems in the eastern United States and Europe that have received high levels of N deposition suggests that added nitrogen is initially sequestered in soil organic matter; yet, our data point to plants as the major initial, though likely ephemeral, N sink. This finding, along with others at our study site, implies that amount and timing of biological N uptake is likely to be a significant control over in the fate of increasing N inputs to alpine tundra. Therefore, changes in plant or microbial community composition resulting from N enrichment could exacerbate losses of N from the tundra. Clarifying the partitioning between biotic and abiotic sinks for N is essential to understanding terrestrial capacity for N sequestration, and for predicting how continued N enrichment will influence future N uptake and loss from this system.
DE: 1600 GLOBAL CHANGE (New category)
DE: 1615 Biogeochemical processes (4805)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting