Groundwater data improve modelling of headwater stream CO2 outgassing with a stable DIC isotope approach

Journal article
(Original article)


Publication Details

Author(s): Marx A, Conrad M, Aizinger V, Prechtel A, van Geldern R, Barth J
Journal: Biogeosciences
Publication year: 2018
Volume: 15
Journal issue: 10
Pages range: 3093-3106
ISSN: 1726-4170
eISSN: 1726-4189
Language: English


Abstract

A large portion of terrestrially derived carbon outgasses as carbon dioxide (CO2) from streams and rivers to the atmosphere. Particularly, the amount of CO2 outgassing from small headwater streams is highly uncertain. Conservative estimates suggest that they contribute 36 % (i.e. 0.93 petagrams (Pg) C yr−1) of total CO2 outgassing from all fluvial ecosystems on the globe. In this study, stream pCO2, dissolved inorganic carbon (DIC), and δ13CDIC data were used to determine CO2 outgassing from an acidic headwater stream in the Uhlířská catchment (Czech Republic). This stream drains a catchment with silicate bedrock. The applied stable isotope model is based on the principle that the 13C ∕ 12C ratio of its sources and the intensity of CO2 outgassing control the isotope ratio of DIC in stream water. It avoids the use of the gas transfer velocity parameter (k), which is highly variable and mostly difficult to constrain. Model results indicate that CO2 outgassing contributed more than 80 % to the annual stream inorganic carbon loss in the Uhlířská catchment. This translated to a CO2 outgassing rate from the stream of 34.9 kg C m−2 yr−1 when normalised to the stream surface area. Large temporal variations with maximum values shortly before spring snowmelt and in summer emphasise the need for investigations at higher temporal resolution. We improved the model uncertainty by incorporating groundwater data to better constrain the isotope compositions of initial DIC. Due to the large global abundance of acidic, humic-rich headwaters, we underline the importance of this integral approach for global applications.


FAU Authors / FAU Editors

Aizinger, Vadym
Professur für Angewandte Mathematik (Wissenschaftliches Rechnen)
Barth, Johannes Prof.
Lehrstuhl für Angewandte Geologie
Marx, Anne
Lehrstuhl für Angewandte Geologie
Prechtel, Alexander Dr.
Lehrstuhl für Angewandte Mathematik
van Geldern, Robert PD Dr.
Lehrstuhl für Angewandte Geologie


How to cite

APA:
Marx, A., Conrad, M., Aizinger, V., Prechtel, A., van Geldern, R., & Barth, J. (2018). Groundwater data improve modelling of headwater stream CO2 outgassing with a stable DIC isotope approach. Biogeosciences, 15(10), 3093-3106. https://dx.doi.org/10.5194/bg-15-3093-2018

MLA:
Marx, Anne, et al. "Groundwater data improve modelling of headwater stream CO2 outgassing with a stable DIC isotope approach." Biogeosciences 15.10 (2018): 3093-3106.

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Last updated on 2018-30-11 at 14:53