Change search
ReferencesLink to record
Permanent link

Direct link
Effects of soil organic matter composition on unfrozen water content and heterotrophic CO2 production of frozen soils
Department of Forest Ecology & Management, Swedish University of Agricultural Sciences. Umeå.
Umeå University, Faculty of Science and Technology, Department of Chemistry.
Umeå University, Faculty of Medicine, Department of Medical Biochemistry and Biophysics.
Department of Forest Ecology & Management, Swedish University of Agricultural Sciences. Umeå.
Show others and affiliations
2010 (English)In: Geochimica et Cosmochimica Acta, ISSN 0016-7037, E-ISSN 0016-1258, Vol. 74, no 8, 2281-90 p.Article in journal (Refereed) Published
Abstract [en]

Several recent studies have highlighted the importance of soil organic matter (SOM) mineralization at high latitudes during winter for ecosystem carbon (C) balances, and the ability of the soil to retain unfrozen water at sub-zero temperatures has been shown to be a major determinant of C mineralization rates. Further, SOM is believed to strongly influence the liquid water contents in frozen surface layers of boreal forest soils and tundra, but the mechanisms and specific factors involved are currently unknown. Here we evaluate the effects of the chemical composition of SUM on the amount of unfrozen water, the pore size equivalents in which unfrozen water can exist, and the microbial heterotrophic activity at sub-zero temperatures in boreal forest soils. To do this, we have characterized the chemical composition of SUM in forest soil samples (surface O-horizons) using solid state CP-MAS (cross polarization magic angle spinning) NMR spectroscopy. The acquired information was then used to elucidate the extent to which different fractions of SUM can explain the observed variations in unfrozen water content, pore size equivalents, and biogenic CO2 production rates in the examined soil samples under frozen conditions (-4 degrees C). The data evaluation was done by the use of principal component analysis (PCA) and projections to latent structures by means of partial least square (PLS). We conclude that aromatic, O-aromatic, methoxy/N-alkyl and alkyl C are the major SOM components affecting frozen boreal forest soil's ability to retain unfrozen water and sustain heterotrophic activity (95% confidence level). Our results reveal that solid carbohydrates have a significant negative impact (95% confidence level) on CO2 production in frozen boreal spruce forest soils, in contrast to the positive effects of carbohydrate polymers during unfrozen conditions. We conclude that the hierarchy of environmental factors controlling SOM mineralization changes as soils freeze. The effect of SUM composition on pore size distribution and unfrozen water content has a superior influence on SUM mineralization and hence on heterotrophic CO2 production of frozen soils. (C) 2010 Elsevier Ltd. All rights reserved.

Place, publisher, year, edition, pages
Elsevier Ltd , 2010. Vol. 74, no 8, 2281-90 p.
Keyword [en]
state c-13 nmr, arctic tundra soils, forest soil, determining quantitation, microbial activity, temperature, respiration, permafrost, quality, litter
National Category
Medical and Health Sciences
URN: urn:nbn:se:umu:diva-33053DOI: 10.1016/J.Gca.2010.01.026ISI: 000275854700003OAI: diva2:309858
572SZ Times Cited:0 Cited References Count:43Available from: 2010-04-09 Created: 2010-04-09 Last updated: 2010-11-30Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full text

Search in DiVA

By author/editor
Sparrman, TobiasSchleucher, Jürgen
By organisation
Department of ChemistryDepartment of Medical Biochemistry and Biophysics
In the same journal
Geochimica et Cosmochimica Acta
Medical and Health Sciences

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 160 hits
ReferencesLink to record
Permanent link

Direct link