HR: 16:30h
AN: NB24F-05    [Abstracts]
TI: Using Natural Hydrologic Variability to Separate the Effects of Water Availability on Hydrologic Transport From the Effects on the Biogeochemical Processing of Nitrogen and Carbon
AU: * Brooks, P D
EM: brooks@hwr.arizona.edu
AF: Hydrology and Water Resources, University of Arizona, 1133 E. North Campus Dr, Tucaon, AZ 85721 United States
AU: Meixner, T
EM: Meixner@hwr.arizona.edu
AF: Hydrology and Water Resources, University of Arizona, 1133 E. North Campus Dr, Tucaon, AZ 85721 United States
AB: The cycling of water, carbon, and nitrogen are intimately linked at a wide range of spatial and temporal scales complicating the interpretation of catchment solute export. Although carbon and nitrogen can affect the hydrologic cycle on longer time scales through changes in vegetation, water availability affects the cycling of carbon and nitrogen on time scales from minutes to centuries. The timing and amount of water variability affect carbon and nitrogen directly through hydrologic transport and indirectly through controlling the biogeochemical processes that effect the size, form, and mobility of carbon and nitrogen species available to be transported to surface water. A large number of terrestrial ecosystems are characterized by a pronounced seasonality in precipitation, water availability, and hydrologic transport of carbon and nitrogen in surface water. This seasonality results in an extended period of time when the importance hydrologic transport on carbon and nitrogen cycling are relatively low while the potential for biogeochemical processing to affect the size of the potentially mobile solute pool is high. In contrast, the importance of hydrologic transport on solute dynamics during the first increases in water availability is high while biogeochemical modification may be delayed or minimized. In these systems the effects of antecedent water availability on biogeochemical processes during the relatively dry season can be evaluated separately from the effects of transport at the initiation of the wet season aiding interpretation of catchment solute export. We will present examples of using this approach to help explain solute dynamics in snowmelt dominated cathments in Colorado, semi-arid systems in Arizona and New Mexico, and mediterranean catchments in California.
DE: 1615 Biogeochemical processes (4805)
DE: 1655 Water cycles (1836)
DE: 1860 Runoff and streamflow
DE: 1871 Surface water quality
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly