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| Titel |
Drivers of long-term variability in CO2 net ecosystem exchange in a temperate peatland |
| VerfasserIn |
C. Helfter, C. Campbell, K. J. Dinsmore, J. Drewer, M. Coyle, M. Anderson, U. Skiba, E. Nemitz, M. F. Billett, M. A. Sutton |
| 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 (2015-03-18), S.1799-1811 |
| Datensatznummer |
250117869
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| Publikation (Nr.) |
 copernicus.org/bg-12-1799-2015.pdf |
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| Zusammenfassung |
Land–atmosphere exchange of carbon dioxide (CO2) in peatlands exhibits
marked seasonal and inter-annual variability, which subsequently affects the
carbon (C) sink strength of catchments across multiple temporal scales.
Long-term studies are needed to fully capture the natural variability and
therefore identify the key hydrometeorological drivers in the net ecosystem
exchange (NEE) of CO2. Since 2002, NEE has been measured continuously
by eddy-covariance at Auchencorth Moss, a temperate lowland peatland in
central Scotland. Hence this is one of the longest peatland NEE studies to
date. For 11 years, the site was a consistent, yet variable, atmospheric
CO2 sink ranging from −5.2 to −135.9 g CO2-C m−2 yr−1
(mean of −64.1 ± 33.6 g CO2-C m−2 yr−1). Inter-annual
variability in NEE was positively correlated to the length of the growing
season. Mean winter air temperature explained 87% of the inter-annual
variability in the sink strength of the following summer, indicating an
effect of winter climate on local phenology. Ecosystem respiration
(Reco) was enhanced by drought, which also depressed gross primary
productivity (GPP). The CO2 uptake rate during the growing season was
comparable to three other sites with long-term NEE records; however, the emission
rate during the dormant season was significantly higher. To summarise, the
NEE of the peatland studied is modulated by two dominant factors:
- phenology of the plant community, which is driven by winter air temperature and impacts photosynthetic potential and net CO2 uptake during the growing season (colder winters are linked to lower summer
NEE),
- water table level, which enhanced soil respiration and decreased GPP during dry spells.
Although summer dry spells were sporadic during the study period, the
positive effects of the current climatic trend towards milder winters on the
site's CO2 sink strength could be offset by changes in precipitation
patterns especially during the growing season. |
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