Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Biogeosciences, 11, 3369-3380, 2014
http://www.biogeosciences.net/11/3369/2014/
doi:10.5194/bg-11-3369-2014
© Author(s) 2014. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
24 Jun 2014
Degradation changes stable carbon isotope depth profiles in palsa peatlands
J. P. Krüger1, J. Leifeld2, and C. Alewell1 1Environmental Geosciences, University of Basel, Basel, Switzerland
2Agroscope Reckenholz-Tänikon Research Station ART, Zürich, Switzerland
Abstract. Palsa peatlands are a significant carbon pool in the global carbon cycle and are projected to change by global warming due to accelerated permafrost thaw. Our aim was to use stable carbon isotopes as indicators of palsa degradation. Depth profiles of stable carbon isotopes generally reflect organic matter dynamics in soils with an increase of δ13C values during aerobic decomposition and stable or decreasing δ13C values with depth during anaerobic decomposition. Stable carbon isotope depth profiles of undisturbed and degraded sites of hummocks as well as hollows at three palsa peatlands in northern Sweden were used to investigate the degradation processes. The depth patterns of stable isotopes clearly differ between intact and degraded hummocks at all sites. Erosion and cryoturbation at the degraded sites significantly changes the stable carbon isotope depth profiles. At the intact hummocks the uplifting of peat material by permafrost is indicated by a turning in the δ13C depth trend, and this assessment is supported by a change in the C / N ratios. For hollows isotope patterns were less clear, but some hollows and degraded hollows in the palsa peatlands show differences in their stable carbon isotope depth profiles indicating enhanced degradation rates. We conclude that the degradation of palsa peatlands by accelerated permafrost thawing can be identified with stable carbon isotope depth profiles. At intact hummocks δ13C depth patterns display the uplifting of peat material by a change in peat decomposition processes.

Citation: Krüger, J. P., Leifeld, J., and Alewell, C.: Degradation changes stable carbon isotope depth profiles in palsa peatlands, Biogeosciences, 11, 3369-3380, doi:10.5194/bg-11-3369-2014, 2014.
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