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| Titel |
The role of watershed characteristics, permafrost thaw, and wildfire on dissolved organic carbon biodegradability and water chemistry in Arctic headwater streams |
| VerfasserIn |
J. R. Larouche, B. W. Abbott, W. B. Bowden, J. B. Jones |
| 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. 14 ; Nr. 12, no. 14 (2015-07-20), S.4221-4233 |
| Datensatznummer |
250118025
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| Publikation (Nr.) |
 copernicus.org/bg-12-4221-2015.pdf |
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| Zusammenfassung |
| In the Alaskan Arctic, rapid climate change is increasing the frequency of
disturbance including wildfire and permafrost collapse. These pulse
disturbances may influence the delivery of dissolved organic carbon (DOC) to
aquatic ecosystems, however the magnitude of these effects compared to the
natural background variability of DOC at the watershed scale is not well
known. We measured DOC quantity, composition, and biodegradability from 14
river and stream reaches (watershed sizes ranging from 1.5–167 km2)
some of which were impacted by permafrost collapse (thermokarst) and fire.
We found that region had a significant impact on quantity and
biodegradability of DOC, likely driven by landscape and watershed
characteristics such as lithology, soil and vegetation type, elevation, and
glacial age. However, contrary to our hypothesis, we found that streams
disturbed by thermokarst and fire did not contain significantly altered
labile DOC fractions compared to adjacent reference waters, potentially due
to rapid ecosystem recovery after fire and thermokarst as well as the
limited spatial extent of thermokarst. Overall, biodegradable DOC ranged
from 4 to 46 % and contrary to patterns of DOC biodegradability in large
Arctic rivers, seasonal variation in DOC biodegradability showed no clear
pattern between sites, potentially related to stream geomorphology and
position along the river network. While thermokarst and fire can alter DOC
quantity and biodegradability at the scale of the feature, we conclude that
tundra ecosystems are resilient to these types of disturbance. |
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