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| Titel |
Catchment-scale dissolved carbon concentrations and export estimates across six subarctic streams in northern Sweden |
| VerfasserIn |
R. Giesler, S. W. Lyon, C.-M. Mörth, J. Karlsson, E. M. Karlsson, E. J. Jantze, G. Destouni, C. Humborg |
| 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 ; 11, no. 2 ; Nr. 11, no. 2 (2014-01-31), S.525-537 |
| Datensatznummer |
250117157
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| Publikation (Nr.) |
 copernicus.org/bg-11-525-2014.pdf |
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| Zusammenfassung |
| Climatic change is currently enhancing permafrost thawing and the flow of
water through the landscape in subarctic and arctic catchments, with major
consequences for the carbon export to aquatic ecosystems. We studied stream
water carbon export in several tundra-dominated catchments in northern
Sweden. There were clear seasonal differences in both dissolved organic
carbon (DOC) and dissolved inorganic carbon (DIC) concentrations. The highest
DOC concentrations occurred during the spring freshet while the highest DIC
concentrations were always observed during winter baseflow conditions for the
six catchments considered in this study. Long-term trends for the period 1982
to 2010 for one of the streams showed that DIC concentrations has increased
by 9% during the 28 yr of measurement while no clear trend was found
for DOC. Similar increasing trends were also found for conductivity, Ca and
Mg. When trends were discretized into individual months, we found a
significant linear increase in DIC concentrations with time for September,
November and December. In these subarctic catchments, the annual mass of C
exported as DIC was in the same order of magnitude as DOC; the average
proportion of DIC to the total dissolved C exported was 61% for the six
streams. Furthermore, there was a direct relationship between total runoff
and annual dissolved carbon fluxes for these six catchments. These
relationships were more prevalent for annual DIC exports than annual DOC
exports in this region. Our results also highlight that both DOC and DIC can
be important in high-latitude ecosystems. This is particularly relevant in
environments where thawing permafrost and changes to subsurface ice due to
global warming can influence stream water fluxes of C. The large proportion
of stream water DIC flux also has implications on regional C budgets and
needs to be considered in order to understand climate-induced feedback
mechanisms across the landscape. |
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