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| Titel |
Ecosystem recovery: a neglected factor in greenhouse gas emission from permafrost degradation. |
| VerfasserIn |
J. van Huissteden, Y. Mi, A. Gallagher, A. Budishchev |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250060692
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| Zusammenfassung |
| It is estimated that northern soils hold nearly twice as much carbon as the atmosphere.
Permafrost degradation caused by a warming climate will destabilize this carbon store. Part
of this carbon will enter the atmosphere as CO2 or CH4, contributing to a positive feedback
on climate warming.
However, a neglected factor is the recovery of ecosystems after permafrost thaw.
Modeling of thaw lake expansion and drainage has shown that thaw lake expansion by
climatic warming is strongly limited by lake drainage. Thaw lakes are drained or filled in with
sediment, followed by recolonization by generally productive wetland ecosystems.
Decomposition of soil carbon also releases nutrients, enhancing vegetation recolonization in
types of permafrost degradation features.
Examples from the Kytalyk/Chokurdagh research site in the Indigirka lowlands of
northeastern Siberia illustrate that ecosystem recovery after localized permafrost degradation
may effectively counteract carbon loss. The research site is located in a drained Early
Holocene thaw lake basin, and is presently a greenhouse gas sink during the growing season.
Formation of thaw ponds has increased strongly recently. Although fresh ponds may be
emitting CO2 and CH4, they are rapidly invaded by vegetation which decreases
net greenhouse gas emission, although the ponds continue to be a source of CH4.
Areas of intense mass wasting by permafrost slides are colonized by a productive
pioneer vegetation, contributing to stabilization of the soil and enhancing CO2
uptake.
It is therefore essential that not only the greenhouse gas emission related to
permafrost degradation is quantified, but also the carbon sinks and recovery rates.
Paleo-environmental and geomorphological studies may help to quantify recovery processes,
in particular those processes that leave their trace in the sedimentary record. For instance
Pleistocene and younger thaw lake deposits in Europe and Siberia may provide
information on carbon loss and carbon storage in successive stages of development. |
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