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Presented at the NABS Annual meeting, Pittsburgh, Pennsylvania, 2002
in Biogeochemistry
NUTRIENT UPTAKE IN 10 NEW YORK STREAMS UNDER DIFFERENT FLOW REGIMES.
L.A. Martin, J.D. Newbold, L.A. Kaplan, and C.L. Dow. Stroud Water Research Center, 970 Spencer Road, Avondale, PA 19311
Nutrient uptake is a measure of stream ecosystem function often used to describe metabolic activity, nutrient retention, and rates of utilization, and their influences on downstream processing. We measured nutrient uptake in 10 New York streams by whole-stream injections of standard solutions of ammonium (NH4+), inorganic phosphorus (PO4-3), organic carbon (C, glucose and arabinose), and a conservative tracer (bromide) from June through October in 2000 and 2001. Nutrient concentrations measured at 5 stations in each stream were fitted to a 1-D advection-dispersion and transient storage model. From 2000 to 2001, streamflow decreased in 7 streams and increased in 3 streams. Uptake length (Sw) varied positively with streamflow for all nutrients except P (p<0.05, sign test). Uptake velocity (Vf) showed no consistent response to streamflow or velocity. The low Vf in a few of the streams are suggestive of saturated nutrient conditions reflected in the relatively high background NH4+ and PO4-3 concentrations, while the low Vf and inconsistent Sw in one stream may be directly attributed to benthic scouring during a major storm a few days prior to the nutrient injections.
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