HR: 1330h
AN: B33E-24    [Abstracts]
TI: The Infuence of Physical Variables on Whole-Stream Metabolism in an Arctic Tundra River
AU: * Cappelletti, C K
EM: Carl.Cappelletti@uvm.edu
AF: Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT 05405 United States
AU: Bowden, W
EM: Breck.Bowden@uvm.edu
AF: Rubenstein School of Environment and Natural Resources, University of Vermont, Burlington, VT 05405 United States
AB: We examined the influence of light, temperature, nutrients, and discharge on whole-stream metabolism (WSM) in three experimental reaches of the Kuparuk River, Alaska, using the open-system, single-station method. Ambient PO₄ levels in the reference reach were ~0.05μM, while addition of phosphoric acid since 1983 in the fertilized reach and since 2004 in the ultra-fertilized reach increased PO₄ levels to ~0.30μM and ~0.90μM, respectively. Among all reaches, gross primary production (GPP) was positively correlated with light, temperature, and PO₄ and negatively correlated with discharge. Temperature explained most of the variance in GPP. Among all reaches, community respiration (CR) was weakly correlated with light, temperature, PO₄, and discharge. However, CR showed a greater response to temperature in the fertilized reaches. Benthic respiration by mosses in the fertilized reaches responds to temperature while heterotrophic respiration in the hyporheic zone is similar in all reaches and does not respond to temperature due to thermal buffering. Light, temperature, and discharge were moderately intercorrelated. An Information-Theoretic approach using Akaike's Information Criterion (AIC) was used to examine the relative importance of each physical variable on WSM and to develop a photosynthesis model.
DE: 1860 Runoff and streamflow
DE: 4842 Modeling
DE: 4853 Photosynthesis
DE: 9315 Arctic region
DE: 9901 NABS Student Award - Basic Research
SC: Biogeosciences [B]
MN: 2005 Joint Assembly