Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach
A large portion of terrestrially derived carbon outgasses as carbon dioxide (CO<sub>2</sub>) from streams and rivers to the atmosphere. Particularly, the amount of CO<sub>2</sub> outgassing from small headwater streams is highly uncertain. Conservative estimates suggest th...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2018-05-01
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| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/15/3093/2018/bg-15-3093-2018.pdf |
| _version_ | 1818570395384545280 |
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| author | A. Marx M. Conrad V. Aizinger V. Aizinger A. Prechtel R. van Geldern J. A. C. Barth |
| author_facet | A. Marx M. Conrad V. Aizinger V. Aizinger A. Prechtel R. van Geldern J. A. C. Barth |
| author_sort | A. Marx |
| collection | DOAJ |
| description | A large portion of terrestrially derived carbon outgasses as carbon dioxide
(CO<sub>2</sub>) from streams and rivers to the atmosphere. Particularly, the
amount of CO<sub>2</sub> outgassing from small headwater streams
is highly uncertain. Conservative estimates suggest that they contribute
36 % (i.e. 0.93 petagrams (Pg) C yr<sup>−1</sup>) of total CO<sub>2</sub> outgassing
from all fluvial ecosystems on the globe. In this study, stream <i>p</i>CO<sub>2</sub>,
dissolved inorganic carbon (DIC), and <i>δ</i><sup>13</sup>C<sub>DIC</sub> data
were used to determine CO<sub>2</sub> 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 <sup>13</sup>C ∕ <sup>12</sup>C ratio of its sources and the
intensity of CO<sub>2</sub> outgassing control the isotope ratio of DIC in stream
water. It avoids the use of the gas transfer velocity parameter (<i>k</i>), which
is highly variable and mostly difficult to constrain. Model results indicate
that CO<sub>2</sub> outgassing contributed more than 80 % to the annual stream
inorganic carbon loss in the Uhlířská catchment. This translated
to a CO<sub>2</sub> outgassing rate from the stream of 34.9 kg
C m<sup>−2</sup> yr<sup>−1</sup> 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. |
| first_indexed | 2024-12-14T13:40:47Z |
| format | Article |
| id | doaj.art-1c44985eb29e459c9f3fd3e0422b08f6 |
| institution | Directory Open Access Journal |
| issn | 1726-4170 1726-4189 |
| language | English |
| last_indexed | 2024-12-14T13:40:47Z |
| publishDate | 2018-05-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Biogeosciences |
| spelling | doaj.art-1c44985eb29e459c9f3fd3e0422b08f62022-12-21T22:59:28ZengCopernicus PublicationsBiogeosciences1726-41701726-41892018-05-01153093310610.5194/bg-15-3093-2018Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approachA. Marx0M. Conrad1V. Aizinger2V. Aizinger3A. Prechtel4R. van Geldern5J. A. C. Barth6Department of Geography and Geosciences, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 5, 91054 Erlangen, GermanyDepartment of Mathematics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 11, 91058 Erlangen, GermanyDepartment of Mathematics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 11, 91058 Erlangen, GermanyComputing Center, Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, GermanyDepartment of Mathematics, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Cauerstr. 11, 91058 Erlangen, GermanyDepartment of Geography and Geosciences, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 5, 91054 Erlangen, GermanyDepartment of Geography and Geosciences, GeoZentrum Nordbayern, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Schlossgarten 5, 91054 Erlangen, GermanyA large portion of terrestrially derived carbon outgasses as carbon dioxide (CO<sub>2</sub>) from streams and rivers to the atmosphere. Particularly, the amount of CO<sub>2</sub> outgassing from small headwater streams is highly uncertain. Conservative estimates suggest that they contribute 36 % (i.e. 0.93 petagrams (Pg) C yr<sup>−1</sup>) of total CO<sub>2</sub> outgassing from all fluvial ecosystems on the globe. In this study, stream <i>p</i>CO<sub>2</sub>, dissolved inorganic carbon (DIC), and <i>δ</i><sup>13</sup>C<sub>DIC</sub> data were used to determine CO<sub>2</sub> 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 <sup>13</sup>C ∕ <sup>12</sup>C ratio of its sources and the intensity of CO<sub>2</sub> outgassing control the isotope ratio of DIC in stream water. It avoids the use of the gas transfer velocity parameter (<i>k</i>), which is highly variable and mostly difficult to constrain. Model results indicate that CO<sub>2</sub> outgassing contributed more than 80 % to the annual stream inorganic carbon loss in the Uhlířská catchment. This translated to a CO<sub>2</sub> outgassing rate from the stream of 34.9 kg C m<sup>−2</sup> yr<sup>−1</sup> 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.https://www.biogeosciences.net/15/3093/2018/bg-15-3093-2018.pdf |
| spellingShingle | A. Marx M. Conrad V. Aizinger V. Aizinger A. Prechtel R. van Geldern J. A. C. Barth Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach Biogeosciences |
| title | Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach |
| title_full | Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach |
| title_fullStr | Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach |
| title_full_unstemmed | Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach |
| title_short | Groundwater data improve modelling of headwater stream CO<sub>2</sub> outgassing with a stable DIC isotope approach |
| title_sort | groundwater data improve modelling of headwater stream co sub 2 sub outgassing with a stable dic isotope approach |
| url | https://www.biogeosciences.net/15/3093/2018/bg-15-3093-2018.pdf |
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