Abstract


TEMPERATURE SENSITIVITY OF ECOSYSTEM METABOLISM VARIES ACROSS A FLUVIAL NETWORK

Freshwater ecosystem metabolism describes the amount of carbon produced and turned over at the ecosystem level. Ecosystem respiration (ER) and gross primary production (GPP) are driven by a number of controlling variables, including water temperature. To study sensitivity of ecosystem metabolism to temperature, we measured metabolism in 15 streams across a 254-km2 pre-Alpine network in Austria and quantified temperature sensitivity for GPP and ER as described by Arrhenius kinetics. Network-wide ER activation energy (E) was -0.53 eV, which was within the expected range for metabolism kinetics. However, E varied from -0.14 to -0.72 eV across individual sub-catchments for ER. Network-wide E for GPP was 2-fold greater (-0.72 eV) than predicted based on metabolism kinetics and varied across sub-catchments from -0.22 to -1.21 eV. The variability in temperature sensitivity of ER and GPP within the network indicates that individual streams may respond differently to changing environmental conditions, dependent on local factors. Ultimately these patterns appear to unify at the network scale where the whole fluvial network integrates as E for ER and GPP trend towards network-wide values with increasing catchment size.

Authors

Ulseth, A. J., University of Vienna, Austria, amber.ulseth@gmail.com

Singer, G. A., Leibniz-Institue of Freshwater Ecology & Inland Fisheries (IGB), Germany, gabriel.singer@igb-berlin.de

Schelker, J., University of Vienna, Austria, jakob.schelker@univie.ac.at

Battin, T. J., École Polytechnique Fédérale de Lausanne, Switzerland, tom.battin@univie.ac.at

Details

Oral presentation

Session #:112
Date: 2/23/2015
Time: 16:00
Location: Machuca (Floor -2)

Presentation is given by student: No