Can uptake length in streams be determined by nutrient addition experiments? Results from an interbiome comparison study
- 1 December 2002
- journal article
- research article
- Published by University of Chicago Press in Journal of the North American Benthological Society
- Vol. 21 (4), 544-560
- https://doi.org/10.2307/1468429
Abstract
Nutrient uptake length is an important parameter for quantifying nutrient cycling in streams. Although nutrient tracer additions are the preferred method for measuring uptake length under ambient nutrient concentrations, short-term nutrient addition experiments have more frequently been used to estimate uptake length in streams. Theoretical analysis of the relationship between uptake length determined by nutrient addition experiments (SW′) and uptake length determined by tracer additions (SW) predicted that SW′ should be consistently longer than SW, and that the overestimate of uptake length by SW′ should be related to the level of nutrient addition above ambient concentrations and the degree of nutrient limitation. To test these predictions, we used data from an interbiome study of NH4+ uptake length in which 15NH4+ tracer and short-term NH4+ addition experiments were performed in 10 streams using a uniform experimental approach. The experimental results largely confirmed the theoretical predictions: SW′ was consistently longer than SW and SW′:SW ratios were directly related to the level of NH4+ addition and to indicators of N limitation. The experimentally derived SW′:SW ratios were used with the theoretical results to infer the N limitation status of each stream. Together, the theoretical and experimental results showed that tracer experiments should be used whenever possible to determine nutrient uptake length in streams. Nutrient addition experiments may be useful for comparing uptake lengths between different streams or different times in the same stream, however, provided that nutrient additions are kept as low as possible and of similar magnitude.Keywords
This publication has 37 references indexed in Scilit:
- N uptake as a function of concentration in streamsJournal of the North American Benthological Society, 2002
- Characterizing nitrogen dynamics, retention and transport in a tropical rainforest stream using an in situ15N additionFreshwater Biology, 2002
- Quantification of the Nitrogen Cycle in a Prairie StreamEcosystems, 2000
- Analysis of nitrogen cycling in a forest stream during autumn using a 15N‐tracer additionLimnology and Oceanography, 2000
- Sequential diffusion of ammonium and nitrate from soil extracts to a polytetrafluoroethylene trap for 15N determinationAnalytica Chimica Acta, 1991
- Measurement of Phosphorus Uptake Length in Streams: Comparison of Radiotracer and Stable PO4ReleasesCanadian Journal of Fisheries and Aquatic Sciences, 1990
- Growth Rate Responses of Lotic Periphytic Diatoms to Experimental Phosphorus Enrichment: The Influence of Temperature and LightCanadian Journal of Fisheries and Aquatic Sciences, 1988
- Nitrogen Limitation in a Sonoran Desert StreamJournal of the North American Benthological Society, 1986
- Phosphorus Dynamics in a Woodland Stream Ecosystem: A Study of Nutrient SpirallingEcology, 1983
- Continuous ammonium enrichment of a woodland stream: uptake kinetics, leaf decomposition, and nitrificationFreshwater Biology, 1983