Abstract


NETWORK-SCALE CO2 EVASION IN A LOWER ALPINE WATERSHED OF THE AUSTRIAN ALPS

Surface waters contribute substantially to CO2 emissions to the atmosphere. However, global estimates remain uncertain due to methodological difficulties, such as the lack of precise estimates of gas transfer in steep upland streams. Here we address the question of what drives CO2 evasion from a steep mountainous stream network of the European Alps by assessing the spatial variation of pCO2 and KCO2 for 148 locations within this watershed. Our results show that log KCO2 can be predicted reasonably well (r2= 0.71, p<0.001, n=86) using a statistical model based on physical and hydrodynamic predictors. Furthermore, all stream reaches were supersaturated in CO2 with a median excess of 53 µg L-1 of C and some variation due to stream order and season. These data yielded median CO2 evasion rates of 96 and 39 mg C m-2 h-1 at first to fifth order streams, respectively. Overall we conclude that small, first-order streams act as the predominant conduits for CO2 to the atmosphere in steep mountainous catchments, as they hold the highest potential for gas exchange combined with strong supersaturation of CO2.

Authors

Schelker, J., Department of Limnology & Oceanography, University of Vienna, Austria, jakob.schelker@univie.ac.at

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

Ulseth, A. J., Department of Limnology & Oceanography, University of Vienna, Vienna, Austria, Austria, amber.ulseth@univie.ac.at

Hengsberger, S., Department of Limnology & Oceanography, University of Vienna, Vienna, Austria, Austria

Battin, T. J., Ecohydraulics Lab, School of Architecture, Civil and Environmental Engineering, École Polytechnique , Switzerland, tom.battin@univie.ac.at

Details

Oral presentation

Session #:090
Date: 2/24/2015
Time: 09:00
Location: Room B (Floor -3)

Presentation is given by student: No