Alison Appling's paper on the physiological basis of fine-scale ecosystem nutrient dynamics has been accepted for publication in the prestigious journal The American Naturalist. The core aim of this paper is to understand the magnitude and shape of rising and falling nutrient concentrations in response to daily variation in metabolism, and in responses to other, episodic pulses of nutrients. Alison adopted physiological models of nutrient metabolism that have been used to understand competition and productivity of phytoplankton, but used them to examine how temporal variation in inputs of one resource (light, nitrogen, or phosphorous) influences temporal variation in the export of others. The model shows 1) that the presence or absence of diel nutrient variation or responses to resource pulses may be an indicator of nutrient limitation, 2) that variation in physiological traits can modify the temporal patterns of uptake in response to single or repeated nutrient pulses, and 3) that differences in the physiology of N and P metabolic pathways can de-couple their uptake in time. These findings provide an important theoretical basis for the interpretation of nutrient spiraling measurements from plateau and pulse enrichments and of high-frequency time series obtained from nutrient sensors. Congratulations Alison!
This is the homepage of the Heffernan Lab at Duke University. Here you can find all sorts of information about our research, teaching, and outreach. If you have any questions, contact Dr. Heffernan.
Dr. Jim Heffernan
I am an Assistant Professor in the Nicholas School of the Environment at Duke University. My research is focused on the causes and consequences of major changes in ecosystem structure, mostly in streams and wetlands.
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