Inferring Sources of Nitrate and the Effect of In-stream Processes on Stream Nitrate Concentrations Through End-Member Mixing Analysis in a Mediterranean Stream.

HR: 09:15h
AN: NB51C-04 [Abstracts]
TI: Inferring Sources of Nitrate and the Effect of In-stream Processes on Stream Nitrate Concentrations Through End-Member Mixing Analysis in a Mediterranean Stream.
AU: * Bernal, S
EM: sbernal@ub.edu
AF: Dept. Ecologia Fac. Biologia Universitat de Barcelona, Diagonal 648, Barcelona, 08028 Spain
AU: Butturini, A
EM: abutturini@ceab.csic.es
AF: Centre d'Estudis Avancats de Blanes (CEAB-CSIC), AccＴ a la Cala St.Francesc 14, Blanes-Girona, 17300 Spain
AU: Sabater, F
EM: fsabater@ub.edu
AF: Dept. Ecologia Fac. Biologia Universitat de Barcelona, Diagonal 648, Barcelona, 08028 Spain
AB: The goals of this study were to infer catchment nitrate sources and to elucidate the effect of in-stream processes on streamwater nitrate through the application of end-member mixing analysis (EMMA). The study was performed in Fuirosos, an intermittent stream draining a forested Mediterranean catchment (10.5 km2). Streamwater was collected during 25 storms. Event water, riparian groundwater and water from headwater springs at the point of discharge were also monitored. Streamwater data encompassed the mixing space defined by the 3 end-members only during the 12 storms occurred during the wet period (from December to May). The estimated proportion of water coming from each source of runoff was plotted against stream nitrate concentrations. A positive relationship was understood such as the compartment was a source of nitrate. Nitrate was coming either from event water or groundwater. Nitrate arriving from the catchment to the stream was estimated by multiplying the flowpath nitrate concentrations by the flowpath fractions and summing the products. These predicted concentrations were compared with those measured in Fuirosos on each sampling data. Only at low flows (< 100 l/s) stream nitrate was lower than predicted from catchment sources, indicating that nitrate was retained in the stream.
DE: 1845 Limnology
DE: 1860 Runoff and streamflow
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly