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Presented at the NABS Annual meeting, Anchorage, Alaska, 2006
in Biogeochemistry 2
Patterns of temporal variation in N and P uptake in two streams located at different altitude.
E. Marti1, D. Von Schiller1, A. Argerich2, F. Sabater2, J.L. Riera2, and M. Ribot1.1Centre d'Estudis Avançats de Blanes (CSIC); Accés a la Cala ST. Francesc, 14; 17300 Blanes; Spain, 2Departament d'Ecologia; Universitat de Barcelona; Diagonal, 645; 08028 Barcelona; Spain
The overall aim of our study was to assess temporal variability in nutrient retention on a long-term basis (>> 1 year) in near-pristine streams. This knowledge is essential to evaluate and forecast global change effects on stream biogeochemistry. Here we compared results from monthly short-term additions conducted since autumn 2004 between two streams located at 1300 m and 300 m within the same catchment (La Tordera, NE Spain); and thus, having contrasting local climatic conditions. We examined temporal patterns of uptake lengths for ammonium (Sw-NH4) and phosphate (Sw-PO4) and their relation with stream discharge and water temperature. The range of variation in Sw-NH4 and Sw-PO4 is comparable between streams; however, the temporal variation pattern clearly differs between them. In the higher elevation stream, temporal variation of Sw-NH4 and Sw-PO4 is coupled and mostly follows the temporal pattern of stream discharge. In the lower elevation stream, both hydrological regime and seasonality drive temporal variation of Sw-NH4 and Sw-PO4, but patterns for the two nutrients are somehow reversed. These results suggest that the relative importance of environmental factors, which are susceptible to climate change, on stream biogeochemical response varies with both local climatic conditions and the nutrient under consideration.
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