High carbon sequestration in Siberian permafrost loess-paleosols during glacials 1Geological Sciences, Brown University, Providence, USA
16 May 2011
2Institute of Geomorphology and Department of Soil Physics, University of Bayreuth, Germany
3Institute of Soil Science and Soil Geography, University of Bayreuth, Germany
*current address: Geological Institute, ETH Zurich, Switzerland
Received: 26 September 2010 – Published in Clim. Past Discuss.: 15 October 2010 Abstract. Recent findings show that the amount of organic carbon stored in
high-latitude permafrost regions has been greatly underestimated. While
concerns are rising that thawing permafrost and resultant CO2 and
methane emissions are a positive feedback mechanism at times of
anthropogenic global warming, the potential role of permafrost carbon
dynamics on glacial-interglacial timescales has received little attention.
Revised: 12 May 2011 – Accepted: 12 May 2011 – Published: 16 May 2011
Here we present new results from a well-studied permafrost loess-paleosol
sequence in north-east Siberia that almost spans two glacial cycles (~220 ka). We analysed the deuterium/hydrogen isotopic ratios (δD) of
alkanes, which serve as proxy for paleo-temperature. Thus circumventing
difficulties to obtain exact age control for such sequences, the results
corroborate our previous notion that more soil organic carbon was
sequestered during glacials than during interglacials. This fact highlights
the role of permafrost in favouring preservation of soil organic matter.
Reduced biomass production during glacials may have been of second-order
importance on these timescales.
Although future studies are needed to evaluate existing large estimates of
carbon dioxide releases from thawing permafrost during the last termination
(>1000 Pg C), we suggest that permafrost carbon dynamics contributed to
the observed glacial-interglacial variation in atmospheric CO2 and need
to be included in carbon cycle and climate models.
Citation: Zech, R., Huang, Y., Zech, M., Tarozo, R., and Zech, W.: High carbon sequestration in Siberian permafrost loess-paleosols during glacials, Clim. Past, 7, 501-509, doi:10.5194/cp-7-501-2011, 2011.