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| Titel |
Carbon dioxide transport across the hillslope–riparian–stream continuum in a boreal headwater catchment |
| VerfasserIn |
F. I. Leith, K. J. Dinsmore, M. B. Wallin, M. F. Billett, K. V. Heal, H. Laudon, M. G. Öquist, K. Bishop |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 12, no. 6 ; Nr. 12, no. 6 (2015-03-23), S.1881-1892 |
| Datensatznummer |
250117874
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| Publikation (Nr.) |
 copernicus.org/bg-12-1881-2015.pdf |
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| Zusammenfassung |
Headwater streams export CO2 as lateral downstream export and
vertical evasion from the stream surface. CO2 in boreal headwater
streams generally originates from adjacent terrestrial areas, so determining
the sources and rate of CO2 transport along the
hillslope–riparian–stream continuum could improve estimates of CO2
export via the aquatic pathway, especially by quantifying evasion at higher
temporal resolutions. Continuous measurements of dissolved CO2
concentrations and water table were made along the hillslope–riparian–stream
continuum in the Västrabäcken sub-catchment of the Krycklan
catchment, Sweden. Daily water and CO2 export from the hillslope and
riparian zone were estimated over one hydrological year
(October 2012–September 2013) using a flow-concentration model and compared
with measured lateral downstream CO2 export.
Total water export over the hydrological year from the hillslope was
230 mm yr−1 compared with 270 mm yr−1 from the
riparian zone. This corresponds well (proportional to the relative upslope
contributing area) to the annual catchment runoff of 265 mm yr−1.
Total CO2 export from the riparian zone to the stream was
3.0 g CO2-C m−2 yr−1. A hotspot for riparian
CO2 export was observed at 30–50 cm depth (accounting for
71 % of total riparian export). Seasonal variability was high with export
peaks during the spring flood and autumn storm events. Downstream lateral
CO2 export (determined from stream water dissolved CO2
concentrations and discharge) was
1.2 g CO2-C m−2 yr−1. Subtracting downstream lateral
export from riparian export (3.0 g CO2-C m−2 yr−1)
gives 1.8 g CO2-C m−2 yr−1 which can be attributed
to evasion losses (accounting for 60 % of export via the aquatic
pathway). The results highlight the importance of terrestrial CO2
export, especially from the riparian zone, for determining catchment aquatic
CO2 losses and the importance of the CO2 evasion component to
carbon export via the aquatic conduit. |
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