Soil Biology and Biochemistry, Dec, 2013, Vol.67, p.133(7)
To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.soilbio.2013.08.003 Byline: Thimo Klotzbucher, Klaus Kaiser, Timothy R. Filley, Karsten Kalbitz Abstract: Dissolved organic matter (DOM) plays a fundamental role for many soil processes. For instance, production, transport, and retention of DOM control properties and long-term storage of organic matter in mineral soils. Production of water-soluble compounds during the decomposition of plant litter is a major process providing DOM in soils. Herein, we examine processes causing the commonly observed increase in contribution of aromatic compounds to WSOM during litter decomposition, and unravel the relationship between lignin degradation and the production of aromatic WSOM. We analysed amounts and composition of water-soluble organic matter (WSOM) produced during 27 months of decomposition of leaves and needles (ash, beech, maple, spruce, pine). The contribution of aromatic compounds to WSOM, as indicated by the specific UV absorbance of WSOM, remained constant or increased during decomposition. However, the contribution of lignin-derived compounds to the total phenolic products of.sup.13C-labelled tetramethylammonium hydroxide (.sup.13C-TMAH) thermochemolysis increased strongly (by 〉114%) within 27 months of decomposition. Simultaneous changes in contents of lignin phenols in solid litter residues (cupric oxide method as well as.sup.13C-TMAH thermochemolysis) were comparably small (-39% to +21% within 27 months). This suggests that the increasing contribution of lignin-derived compounds to WSOM during decomposition does not reflect compositional changes of solid litter residues, but rather the course of decomposition processes. In the light of recently published findings, these processes include: (i) progressive oxidative alteration of lignin that results in increasing solubility of lignin, (ii) preferential degradation of soluble, non-lignin compounds that limits their contribution to WSOM during later phases of decomposition. Author Affiliation: (a) Soil Sciences, Martin-Luther-University Halle-Wittenberg, Halle (Saale), Germany (b) Department of Earth and Atmospheric Sciences and the Purdue Climate Change Research Center, Purdue University, West Lafayette, IN, USA (c) Earth Surface Science, Institute for Biodiversity and Ecosystem Dynamics (IBED), University of Amsterdam, Amsterdam, The Netherlands Article History: Received 13 March 2013; Revised 19 July 2013; Accepted 3 August 2013
Control Equipment Industry -- Production Processes ; Lignin ; Global Temperature Changes ; Hydroxides ; Copper Oxides ; Aromatic Compounds
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