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| Titel |
A temporal study of permafrost thaw for a subarctic peatland in northern Sweden |
| VerfasserIn |
John Connolly, Andreas Persson, Marco Giljum, Patrick Crill, Nigel Roulet, Lars Eklundh, Petter Pilesjö |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250096545
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| Publikation (Nr.) |
 EGU/EGU2014-12053.pdf |
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| Zusammenfassung |
| Peatlands or mires contain about one third of the global terrestrial carbon pool and are located
on between 3-6% of the global land area. In boreal and sub-arctic regions peatland cover
about 3.5 million km2 and are underlain with continuous, discontinuous, sporadic and
isolated patches of permafrost. In these areas the soil organic carbon (SOC) pools are stable
and decomposition is suspended only as long as the soil is frozen or in an anaerobic
state. Climate warming is projected to be greater in the high latitudes where most
northern peatlands are found. Observed mean annual air temperatures in northern
Sweden have increased by 2-3oC since the 1950s. This is causing permafrost thaw
and increasing the vulnerability of peatland C, especially in discontinuous and
sporadic permafrost area. A growing number of studies have examined the impact of
climate-induced thaw and the potential vulnerability of carbon stored in frozen
peatlands.
Thawing permafrost leads to changes in the form and function of northern peatlands. This
is characterised by the transition of dry palsa mires to wetter peatland pits, depressions and
pools. These new hydrological regimes also lead to increased production of methane through
subsequent decomposition of plant material. Increases in temperature therefore leads to
changes in permafrost distribution, receding palsa areas, geomorphology (thermokarst
terrain), hydrology (thus affecting plant community structure, productivity, increased wetter
vegetation communities) and C efflux.
An increasing number of studies examining the impact of climate change on peatlands in
these regions and measurement of CO2 and CH4 fluxes occurs at several discrete peatland
sites across the sub-Arctic. However, regional estimations of these fluxes are limited.
Geospatial technologies may be used to aid the understanding of the patterns and
processes that are occurring in these transition mires over space and time. Several
satellite and airborne images have been acquired for Stordalen mire, a palsa peatland
in northern Sweden, over a temporal period of 40 years. The imagery database
comprises of aerial and satellite imagery from 1970 to 2013. Two studies in the
mid-2000s found that the palsa peatland had become wetter in the period from
1970 to 2000. We are continuing this work to see if that trend has continued and to
determine if the rate of thaw has increased in the period between 2000 and 2013. |
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