Details
| Original language | English |
|---|---|
| Pages (from-to) | 37-47 |
| Number of pages | 11 |
| Journal | Science of the Total Environment, The |
| Volume | 152 |
| Issue number | 1 |
| Publication status | Published - 25 Jul 1994 |
| Externally published | Yes |
Abstract
Dissolved organic carbon (DOC) in forest soils exerts a profound influence on soil internal carbon fluxes. We focused our research on whether DOC mobilized in the forest floor can be already classified as humic material. Our approach comprises chemical structural studies of DOC fractions by degradative methods, CPMAS 13C-NMR spectroscopy, and pyrolysis-field ionization mass spectrometry. Hydrophobic acids are mainly composed of plant-derived compounds which become water-soluble by oxidative biodegradation. A part of the carbohydrate moieties in this fraction is probably covalently bound to phenolic structures in lignocellulose-degradation products. As indicated by the higher degree of biooxidation the hydrophilic acids appear to be genetically downstream from the hydrophobic acids. Hydrophobic neutrals are mainly composed of only slightly altered plant-derived material, with less degraded lignin moieties and relatively high contents of non-carbohydrate aliphatics. Hydrophilic neutrals are characterized by the highest concentrations of carbohydrates derived from plant and microbial origin. DOC represents a continuum of organic substances from only slightly modified plant-derived oligosaccharides over highly altered lignin-derived compounds to products of microbial resynthesis. In contrast to the recalcitrant organic matter in humic soil horizons, hydrophobic acids do not show two main characteristics of humification, which can be addressed as enrichment of C-C linked aromatic moieties and as cross-linking of aliphatic compounds. Nevertheless, the hydrophobic acids in particular can be attributed as precursors of humic substances in illuvial soil horizons.
Keywords
- C-NMR spectroscopy, Degradative characterization, DOC fractionation, DOC mobilization, Pyrolysis-mass spectrometry
ASJC Scopus subject areas
- Environmental Science(all)
- Environmental Engineering
- Environmental Science(all)
- Environmental Chemistry
- Environmental Science(all)
- Waste Management and Disposal
- Environmental Science(all)
- Pollution
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In: Science of the Total Environment, The, Vol. 152, No. 1, 25.07.1994, p. 37-47.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Dissolved organic carbon in forest floor leachates: simple degradation products or humic substances?
AU - Guggenberger, Georg
AU - Zech, Wolfgang
N1 - Funding information: This work was supported by the Bayerisches Ministerium fiir Landesentwicklung und Umwelt-fragen. We are indebted to Professor Dr H.-R. Schulten (Fachhochschule Fresenius, Wiesbaden) for recording the pyrolysis-field ionization mass spectra. We also thank Wolfram G6tz and Bruno Glaser for their laboratory assistance.
PY - 1994/7/25
Y1 - 1994/7/25
N2 - Dissolved organic carbon (DOC) in forest soils exerts a profound influence on soil internal carbon fluxes. We focused our research on whether DOC mobilized in the forest floor can be already classified as humic material. Our approach comprises chemical structural studies of DOC fractions by degradative methods, CPMAS 13C-NMR spectroscopy, and pyrolysis-field ionization mass spectrometry. Hydrophobic acids are mainly composed of plant-derived compounds which become water-soluble by oxidative biodegradation. A part of the carbohydrate moieties in this fraction is probably covalently bound to phenolic structures in lignocellulose-degradation products. As indicated by the higher degree of biooxidation the hydrophilic acids appear to be genetically downstream from the hydrophobic acids. Hydrophobic neutrals are mainly composed of only slightly altered plant-derived material, with less degraded lignin moieties and relatively high contents of non-carbohydrate aliphatics. Hydrophilic neutrals are characterized by the highest concentrations of carbohydrates derived from plant and microbial origin. DOC represents a continuum of organic substances from only slightly modified plant-derived oligosaccharides over highly altered lignin-derived compounds to products of microbial resynthesis. In contrast to the recalcitrant organic matter in humic soil horizons, hydrophobic acids do not show two main characteristics of humification, which can be addressed as enrichment of C-C linked aromatic moieties and as cross-linking of aliphatic compounds. Nevertheless, the hydrophobic acids in particular can be attributed as precursors of humic substances in illuvial soil horizons.
AB - Dissolved organic carbon (DOC) in forest soils exerts a profound influence on soil internal carbon fluxes. We focused our research on whether DOC mobilized in the forest floor can be already classified as humic material. Our approach comprises chemical structural studies of DOC fractions by degradative methods, CPMAS 13C-NMR spectroscopy, and pyrolysis-field ionization mass spectrometry. Hydrophobic acids are mainly composed of plant-derived compounds which become water-soluble by oxidative biodegradation. A part of the carbohydrate moieties in this fraction is probably covalently bound to phenolic structures in lignocellulose-degradation products. As indicated by the higher degree of biooxidation the hydrophilic acids appear to be genetically downstream from the hydrophobic acids. Hydrophobic neutrals are mainly composed of only slightly altered plant-derived material, with less degraded lignin moieties and relatively high contents of non-carbohydrate aliphatics. Hydrophilic neutrals are characterized by the highest concentrations of carbohydrates derived from plant and microbial origin. DOC represents a continuum of organic substances from only slightly modified plant-derived oligosaccharides over highly altered lignin-derived compounds to products of microbial resynthesis. In contrast to the recalcitrant organic matter in humic soil horizons, hydrophobic acids do not show two main characteristics of humification, which can be addressed as enrichment of C-C linked aromatic moieties and as cross-linking of aliphatic compounds. Nevertheless, the hydrophobic acids in particular can be attributed as precursors of humic substances in illuvial soil horizons.
KW - C-NMR spectroscopy
KW - Degradative characterization
KW - DOC fractionation
KW - DOC mobilization
KW - Pyrolysis-mass spectrometry
UR - http://www.scopus.com/inward/record.url?scp=0028161151&partnerID=8YFLogxK
U2 - 10.1016/0048-9697(94)90549-5
DO - 10.1016/0048-9697(94)90549-5
M3 - Article
AN - SCOPUS:0028161151
VL - 152
SP - 37
EP - 47
JO - Science of the Total Environment, The
JF - Science of the Total Environment, The
SN - 0048-9697
IS - 1
ER -