HR: 10:35h
AN: H12B-02    [Abstracts]
TI: Diffuse Nitrogen Inputs Into Streams: Direct Experimental-Model Comparison and Up-Scaling of Loss Rates in Streams
AU: * Lindgren, G A
EM: gal@kth.se
AF: Royal Institute of Technology, Dept. of Land and Water Resources Engineering, Royal Institute of Technology, Water Resources Engineering, Brinellv 32, Stockholm, 10044 Sweden
AU: Destouni, G
EM: georgia.destouni@natgeo.su.se
AF: Stockholm University, Dept. of Physical Geography and Quaternary Geology, Stockholm University, Dept. of Physical Geography and Quaternary Geology, Stockholm, 10691 Sweden
AB: Diffuse nitrogen input through the hyporheic zone along streams results from nitrogen leakage from sources distributed over the soil surface of catchments. Some nitrogen is then retained and lost from stream water due to biogeochemical and physical mass transfer and attenuation processes. Such losses are often modeled as first-order decay reactions, in both catchment-scale nitrogen transport models and interpretations of stream-reach-scale experiments. We find order of magnitude differences between reported loss rates in low order streams that have been calibrated by catchment-scale nitrogen budget modelling from those given by direct stream-reach-scale measurements. With a relatively simple model methodology, accounting for the spatially distributed character of solute inputs and transport in streams, we show that such discrepancies in loss rates can be explained and accounted for in process-based intrerpretation of catchment-scale nitrogen budget models.
DE: 4845 Nutrients and nutrient cycling
DE: 3210 Modeling
DE: 1869 Stochastic processes
DE: 1871 Surface water quality
DE: 1615 Biogeochemical processes (4805)
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting