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| Titel |
Effect of ablation rings and soil temperature on 3-year spring CO2 efflux along the Dalton Highway, Alaska |
| VerfasserIn |
Y. Kim |
| 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. 23 ; Nr. 11, no. 23 (2014-12-01), S.6539-6552 |
| Datensatznummer |
250117701
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| Publikation (Nr.) |
 copernicus.org/bg-11-6539-2014.pdf |
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| Zusammenfassung |
| Winter and spring soil CO2 efflux measurements represent a
significant component in the assessment of annual carbon budgets of tundra
and boreal forest ecosystems, reflecting responses to climate change in the
Arctic. This study was conducted in order to quantify CO2 efflux,
using a portable chamber system at representative sites along the Dalton
Highway. Study sites included three tundra, two white spruce, and three black
spruce forest locations during the winter and spring seasons of 2010–2012;
the study of these sites promised better understanding of winter and spring
carbon contributions to the annual carbon budget, as well as the respective
ablation-ring effects during spring. Three-year spring CO2 efflux
depends on soil temperature at 5 cm depth on a regional scale. At their
highest, Q10 values were 4.2 × 106, within the exposed tussock
tundra of the upland tundra site, which tundra soils warmed from −0.9 to
0.5 °C, involving soil microbial activity. From the forest census
(400 m2) of the two white spruce forest sites, CO2 emissions
were estimated as 0.09–0.36 gC m−2 day−1 in winter and
0.14–4.95 gC m−2 day−1 in spring, corresponding to
1–3% and 1–27% of annual carbon, respectively. Contributions from
spring CO2 emissions are likely to increase as exposed soils widen in
average length (major axis) from the east-, west-, south-, and north-side lengths
(minor axis). Considering the periods of winter and spring seasons across
tundra and boreal forests, average winter- and spring-seasonal CO2
contributions to annual carbon budgets correspond roughly to 14–22% for
tundra and 9–24% for boreal forest sites during 2011 and 2012. Spring
carbon contributions, such as growing season CO2 emissions, are
sensitive to subtle changes at the onset of spring and during the
snow-covered period in northern high latitudes, in response to recent Arctic
climate change. |
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