Universität zu Köln

Mueller, Carsten W., Rethemeyer, Janet ORCID: 0000-0001-6698-4186, Kao-Kniffin, Jenny, Loeppmann, Sebastian, Hinkel, Kenneth M. and G. Bockheim, James (2015). Large amounts of labile organic carbon in permafrost soils of northern Alaska. Glob. Change Biol., 21 (7). S. 2804 - 2818. HOBOKEN: WILEY. ISSN 1365-2486

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Abstract

Permafrost-affected soils of the northern circumpolar region represent 50% of the terrestrial soil organic carbon (SOC) reservoir and are most strongly affected by climatic change. There is growing concern that this vast SOC pool could transition from a net C sink to a source. But so far little is known on how the organic matter (OM) in permafrost soils will respond in a warming future, which is governed by OM composition and possible stabilization mechanisms. To investigate if and how SOC in the active layer and adjacent permafrost is protected against degradation, we employed density fractionation to separate differently stabilized SOM fractions. We studied the quantity and quality of OM in different compartments using elemental analysis, C-13 solid-phase nuclear magnetic resonance (C-13-NMR) spectroscopy, and C-14 analyses. The soil samples were derived from 16 cores from drained thaw lake basins, ranging from 0 to 5500years of age, representing a unique series of developing Arctic soils over time. The normalized SOC stocks ranged between 35.5 and 86.2kgSOCm(-3), with the major amount of SOC located in the active layers. The SOC stock is dominated by large amounts of particulate organic matter (POM), whereas mineral-associated OM especially in older soils is of minor importance on a mass basis. We show that tremendous amounts of over 25kgOC per square meter are stored as presumably easily degradable OM rich in carbohydrates. Only about 10kgOC per square meter is present as presumably more stable, mineral-associated OC. Significant amounts of the easily degradable, carbohydrate-rich OM are preserved in the yet permanently frozen soil below the permafrost table. Forced by global warming, this vast labile OM pool could soon become available for microbial degradation due to the continuous deepening of the annually thawing active layer.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Mueller, Carsten W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rethemeyer, Janet UNSPECIFIED orcid.org/0000-0001-6698-4186 UNSPECIFIED Kao-Kniffin, Jenny UNSPECIFIED UNSPECIFIED UNSPECIFIED Loeppmann, Sebastian UNSPECIFIED UNSPECIFIED UNSPECIFIED Hinkel, Kenneth M. UNSPECIFIED UNSPECIFIED UNSPECIFIED G. Bockheim, James UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-400357
DOI:	10.1111/gcb.12876
Journal or Publication Title:	Glob. Change Biol.
Volume:	21
Number:	7
Page Range:	S. 2804 - 2818
Date:	2015
Publisher:	WILEY
Place of Publication:	HOBOKEN
ISSN:	1365-2486
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language THAW-LAKE BASINS; ARCTIC TUNDRA; TEMPERATE SOILS; NMR-SPECTROSCOPY; MATTER; STABILIZATION; STOCKS; C-13; MECHANISMS; RESIDUES Multiple languages Biodiversity Conservation; Ecology; Environmental Sciences Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/40035