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QUANTIFYING SEASONAL SHIFTS IN NITROGEN SOURCES TO OREGON ESTUARIES: PART II: TRANSPORT MODELING
Citation:
BROWN, C. A. AND J. E. KALDY, III. QUANTIFYING SEASONAL SHIFTS IN NITROGEN SOURCES TO OREGON ESTUARIES: PART II: TRANSPORT MODELING. Presented at Estuarine Research Federation Meeting, Providence, RI, November 04 - 08, 2007.
Impact/Purpose:
research presentation
Description:
Identifying the sources of dissolved inorganic nitrogen (DIN) in estuaries is complicated by the multiple sources, temporal variability in inputs, and variations in transport. We used a hydrodynamic model to simulate the transport and uptake of three sources of DIN (oceanic, riverine and wastewater treatment facility effluent) to Yaquina Bay, Oregon, USA. Model results were used to determine the importance of advective transport and mixing of DIN sources on spatial and temporal patterns in stable isotope (delta 15N) of macroalgae. Model simulations combined with stable isotope data reveal that during the winter riverine inputs are the dominant sources of nitrogen while during the summer coastal upwelling is the dominant source of nitrogen and wastewater effluent is a minor source of DIN to the estuary. Our novel use of a transport model coupled with stable isotopes allowed the quantification of sources of DIN within the estuary, which would not have been possible using the traditional approach of mixing diagrams due to the number of sources and the temporal variability in inputs.
