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| Titel |
Greenhouse gas flux measurements in a forestry-drained peatland indicate a large carbon sink |
| VerfasserIn |
A. Lohila, K. Minkkinen, M. Aurela, J.-P. Tuovinen, T. Penttilä, P. Ojanen, T. Laurila |
| 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 ; 8, no. 11 ; Nr. 8, no. 11 (2011-11-08), S.3203-3218 |
| Datensatznummer |
250006196
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| Publikation (Nr.) |
 copernicus.org/bg-8-3203-2011.pdf |
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| Zusammenfassung |
| Drainage for forestry purposes increases the depth of the oxic peat layer
and leads to increased growth of shrubs and trees. Concurrently, the
production and uptake of the greenhouse gases carbon dioxide (CO2),
methane (CH4) and nitrous oxide (N2O) change: due to the
accelerated decomposition of peat in the presence of oxygen, drained
peatlands are generally considered to lose peat carbon (C). We measured
CO2 exchange with the eddy covariance (EC) method above a drained
nutrient-poor peatland forest in southern Finland for 16 months in
2004–2005. The site, classified as a dwarf-shrub pine bog, had been ditched
about 35 years earlier. CH4 and N2O fluxes were measured at 2–5-week intervals with the chamber technique. Drainage had resulted in a
relatively little change in the water table level, being on average 40 cm
below the ground in 2005. The annual net ecosystem exchange was
−870 ± 100 g CO2 m−2 yr−1 in the calendar year 2005, indicating net
CO2 uptake from the atmosphere. The site was a small sink of CH4
(−0.12 g CH4 m−2 yr−1) and a small source of N2O
(0.10 g N2O m−2 yr−1). Photosynthesis was detected throughout the
year when the air temperature exceeded −3 °C. As the annual
accumulation of C in the above and below ground tree biomass
(175 ± 35 g C m−2) was significantly lower than the accumulation observed by the
flux measurement (240 ± 30 g C m−2), about 65 g C m−2 yr−1 was likely to have accumulated as organic matter into the peat
soil. This is a higher average accumulation rate than previously reported
for natural northern peatlands, and the first time C accumulation has been
shown by EC measurements to occur in a forestry-drained peatland. Our
results suggest that forestry-drainage may significantly increase the
CO2 uptake rate of nutrient-poor peatland ecosystems. |
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