Abstract


INFLUENCE OF WARMING ON NITROGEN AND PHOSPHORUS UPTAKE AND KINETICS: RESULTS FROM A WHOLE-STREAM WARMING EXPERIMENT

Substantial warming is projected for many aquatic systems over the next century and understanding how this warming will influence the structure and function of aquatic ecosystems is an important goal. While much progress has been made in identifying how ecosystem metabolism is influenced by temperature, relatively little is known about how warming shapes nutrient cycling, particularly at the ecosystem scale. We experimentally warmed an Icelandic headwater stream by approximately 3.5 ˚C by diverting stream water through a gravity-fed heat exchange system. We monitored the experimental stream and a reference for one year prior to and after experimental warming. During summer months of relatively high light availability, warming led to increased ambient uptake rates of NH4-N (150%) and PO3-P (220%), as well as increased uptake capacity at elevated nutrient concentrations. Increases in N and P uptake were associated with greater benthic organic matter standing crop. In general, mass-specific rates of N uptake decreased following warming, but mass-specific rates of P uptake increased. Our results suggest that warming may both increase nutrient retention and influence the coupling of N and P cycles.

http://www.montana.edu/hood/hood/hood/Home.html

Authors

Hood, J. M., Montana State University, USA, hoodx008@umn.edu

Benstead, J. P., University of Alabama, USA, jbenstead@bama.ua.edu

Cross, W. F., Montana State University, USA, wyatt.cross@montana.edu

Huryn, A. D., University of Alabama, USA, huryn@bama.ua.edu

Nelson, D., University of Alabama, USA, dnelson12@crimson.ua.edu

Johnson, P. W., University of Alabama, USA, pjohnson@eng.ua.edu

Junker, J. R., Montana State University, USA, james.junker1@gmail.com

Gíslason, G. M., University of Iceland, Iceland, gmg@hi.is

Ólafsson, J. S., Institute of Freshwater Fisheries, Iceland, jsol@veidimal.is

Details

Oral presentation

Session #:127 B
Date: 5/21/2014
Time: 13:30
Location: B 117 - 119

Presentation is given by student: No