Description: Soils store about two times more carbon than exists in the atmosphere as CO2. Terrestrial eco-sys-tems are driving forces in the global carbon cycle and, if acting as carbon sinks, can become key to mitigate increasing CO2 concentrations in the atmosphere. Global warming probably will affect soil organic carbon decomposition and will determine how much carbon will be transferred to the atmosphere or sequestered in soils. Lignin is one of the main constituents of the cell walls of woody plants and a large contributor to soil or-ganic matter. Lignin is generally believed to be relatively resistant against microbial decompo-sition and that lignin residues contribute significantly to the large stock of old, only slowly de-gradable organic matter in the soil. However, analytical information of lignin biodegradation mostly has been addressed in short-term (days to weeks) in-vitro experiments. In-vivo experiments would mimic natural processes in soils over many years but are sparse. Direct molecular-level information on long-term lignin turnover could come from field studies using the natural stable isotopic difference between C4 plants and C3 plants isotope. When C4 vegetation replaces C3 vegetation, the new, the isotopically heavier C4-derived carbon subsequentially replaces the old, decaying C3 carbon. Thus, increasing d13C values are directly related to the proportion of the new, C4-derived biomass, and can be used to estimate the residence time and pool size of individual soil organic matter components. Compound specific isotope analysis of lignin has been successfully applied to bulk soil organic matter, and solvent-extractable compounds such as soil n-alkanes, but not to individual lignin monomers. For aquatic environments it has been demonstrated that com-pound specific isotope analysis of lignin is possible for some lignin monomers, although still analytical limitations exist. For soil organic matter, however, this technique had not yet been applied so far. In the proposed project the existing expertise on bulk lignin quantification shall be com-bined with the know-how on bulk and compound specific isotope analysis to reach a new level of molecular level information on carbon cycling of soil organic matter. This project may provide a novel, improved analytical tool to gain isotopic information of lignin in plants, soil organic mat-ter. It may also help to clarify our fundamental understanding of the global carbon cycle and thus car-bon sequestration in soils and will improve urgently needed plot based and global turnover models.
SupportProgram
Origins: /Bund/UBA/UFORDAT
Tags: Atmosphärische CO2-Konzentration ? Spülsaum ? Lignin ? Tierhaltungsanlage ? Vegetation ? Bodenkohlenstoff ? Humus ? Kohlenstoff ? Lösungsmittel ? Verrottung ? Saumgesellschaft ? Bodeninformation ? Bodenverbesserung ? Gesamtkohlenstoff ? Kohlenstoffsenke ? Organisches Material ? Verdunstung ? Naturstein ? Technosol ? Globale Erwärmung ? Persistenter Stoff ? Biologischer Abbau ? Abbaubarkeit ? Ackerfläche ? Bodenluft ? Kohlenstoffkreislauf ? Aquatisches Ökosystem ? Technik ? Analyse ? Verwitterung ? Naturfaser ? Stoff ? Wertermittlung ? Bodenprozess ? REACH ? Rückstand ? Umwelt ? Atmosphäre ? Versuchsanlage ? Gebiet ? Biomasse ? Naturpotential ? Globale Aspekte ? Gutachten ? Lagerung ? Boden ? Bedarf ? Staude ? Globalmodell ? Stall ? Beschlagnahme ? WAND ? NEU ? EXPERIMENT ? VERWANDT ? ANALYTISCH ? ALT ? GRUNDLAGE ? Vegetationsgrenze ? NOM [natürlicher organischer Stoff] ? HILF ? ANGEWANDT ? BESTANDTEIL ? Vermehrung ? PROJEKT ? SPEZIFISCH ? In-Vivo ? Isotop ? BESTEHEND ? Kohlenstoffverbindung ?
License: cc-by-nc-nd/4.0
Language: Englisch/English
Time ranges: 2003-05-01 - 2006-10-31
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