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| Titel |
Increased greenhouse gas emission from thaw ponds in Siberian arctic tundra on continuous permafrost. |
| VerfasserIn |
Angela Gallagher, Ko van Huissteden |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250048890
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| Zusammenfassung |
| Arctic regions are expected to experience accelerate permafrost degradation due to
future climate change. This includes both large scale phenomena (expansion of
thaw lakes) and small-scale features, such as surficial pond formation and mass
wasting.
The effects of thaw pond formation were studied at the Kytalyk research station, located
in Indigirka lowlands, Northeast Siberia. This area is located on the drained bed of an Early
Holocene thaw lake. A large part of the area is characterized by the presence of low palsas
(flat ice mounds), covered with mosses and Betula nana shrubs. The edges of these palsas
are subject to frequent thawing, resulting in shallow ponds with decaying palsa
vegetation.
A comparison using high resolution satellite images from 1977 (American Keyhole
project image) and 2010 (Geoeye) show that the number of thaw ponds has increased. Flux
measurement data show elevated emission of CO2 and CH4 from these ponds. A fresh pond
with dead Betula nana showed fluxes of 261 mg CO2 m-2 hr-1 and 29.6 mg CH4 m-2 hr-1
in the summer of 2010. N2O fluxes were not detected.
However, a decrease of greenhouse gas fluxes occurs when Carex and Eriophorum
(sedges) vegetation invades these ponds. The CH4 emission of this vegetation type is still
high (9.1 mg CH4 m-2 hr-1 or -208 mg CO2 eq m-2 hr-1), but this is largely compensated
by rapid CO2 uptake (-146 mg CO2 m-2 hr-1). It is therefore likely that greenhouse gas
emission from this type of shallow permafrost degradation is strongly influenced by
ecosystem recovery rates. |
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