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| Titel |
Holocene carbon dynamics and radiative forcing of three different types of peatlands in Finland |
| VerfasserIn |
Paul Mathijssen, Minna Väliranta, Annalea Lohila, Kari Minkkinen, Eeva-Stiina Tuittila, Juha-Pekka Tuovinen, Aino Korrensalo |
| Konferenz |
EGU General Assembly 2016
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250121635
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| Publikation (Nr.) |
 EGU/EGU2016-428.pdf |
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| Zusammenfassung |
| Peatlands contain approximately a third of all soil carbon globally and as they exchange
carbon dioxide (CO2) and methane (CH4) copiously with the atmosphere, changes in
peatland carbon budgets have a large impact on the global carbon balance and the
concentration of greenhouse gasses in the atmosphere. There has been a growing interest in
reconstructing and linking peatland carbon dynamics to past climate variations,
because quantitative reconstructions can be used as a basis for future carbon balance
predictions. In order to increase our understanding on peatland development and
response patterns we quantitatively reconstructed Holocene carbon dynamics of three
different peatlands in Finland: a subarctic fen, a boreal peatland complex and a boreal
managed pine bog. Several cores from each peatland were investigated. The peatlands
showed distinct successional pathways, which were sometimes triggered by fires.
Successional stages were partly reflected in carbon accumulation patterns. Sometimes
variations in carbon accumulation rates coincided with autogenic changes in peat
type and vegetation, but accumulation rates were also related to the large-scale
Holocene climate phases. However, Holocene climate changes as such did not seem to
result in changes in the peat plant species composition. The mid-Holocene warm
and dry climate conditions reduced the carbon accumulation in the subarctic fen
and in the fen part of the boreal peatland complex, but when the peatland was in
bog phase this effect was not visible. Some bog cores showed a clear increase in
carbon accumulation after fen-bog transition, but the pattern was not unanimous.
In addition to carbon accumulation, we estimated past CH4 emissions for each
peatland respectively by applying different methods and by utilising the established
current vegetation-CH4 emission relationship. The reconstructions showed that CH4
emissions always decreased during bog stages, but that the CH4 emissions played a
major role in the total carbon budget of the peatlands throughout the Holocene.
We combined the long-term effect of carbon accumulation and CH4 emission and
modelled Holocene atmospheric radiative forcing. The radiative forcing models show
that these peatlands had a warming effect on the atmosphere for the first 1 to 2
thousand years since peat accumulation started, after which they had an increasing
cooling effect as a result of the long term effect of uptake and storage of CO2. |
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