400 MHz WB Konsole für Kernspinresonanzspektrometer
Zusammenfassung der Projektergebnisse
Nuclear magnetic resonance (NMR) spectroscopy has become a powerful tool for characterizing soil organic matter composition in natural soils and their fractions. The development of advanced NMR techniques and improvements in instrumental design have opened the door for the application of this technique to various research question mainly related to the stabilization and turnover of organic matter in soils. In recent years, we have used solid-state NMR spectroscopy, mainly for 13C, but also for 15N and 129Xe to investigate the structural association of organic matter with the mineral soil matrix. We could show that the organic matter associated with minerals in early phases of soil development is dominated by N-rich proteinaceous material. This could be deduced from classical chronosequence studies as well as from experiments producing artificial soils from incubation of different mineral materials within the framework of priority programme 1315 “Biogeochemical interfaces in soils”. This is most probably due to the fact that these materials react preferentially with fresh mineral surfaces, such as the iron oxide goethite. Reaction of EPS with goethite led to a preferential adsorption of lipids and proteins. The organic coverage was heterogeneous, consisting of ∼100 × 200 nm large patches of either lipid-rich or protein-rich material. This fraction formed a coating of subμm spaced protein-rich and lipid-rich domains, i.e., of two materials which will strongly differ in their reactive sites. This will finally affect further adsorption, the particle mobility and eventually also colloidal stability. In later stages of soil development carbohydrates - mostly derived from microbial sources - become of more importance. This is in contrast to previous concepts of soil organic matter accumulation that considered aromatic carbon derived from lignin as major type of organic material stabilized in soils. We could show that even in wetland soils, where lignin decomposition is retarded, the major material accumulating in the mineral fractions is of proteinaceous and carbohydrate structures . In the case of iron oxides, the association of organic matter can occur via adsorption or co-precipitation, as shown by Eusterhues et al., 2011. 129Xe NMR spectroscopy of adsorbed xenon indicates that the porous network in which the organic matter is bound may originate from the "multi-domain" structure of soil clay particles, i.e. particles formed by agglomerated nano-sized crystallites together with organic material. If the soil structures formed from these organo-mineral associations are disrupted, an increased mineralization measured as released CO2 is observed, indicating the sensitivity of organic matter associated with the soil mineral phase to land use changes or other disruption.
Projektbezogene Publikationen (Auswahl)
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Organic matter in four Brazilian soil types: chemical composition and atrazine sorption. Química Nova, Vol. 33. 2010, no.1, pp. 14-19.
Dick D.P., Martinazzo R., Knicker H., Almeida P.S.G.
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Thermal alteration of organic matter during a shrubland fire: A field study. Organic Geochemistry, Vol. 41. 2010, Issue 7, pp. 690-697.
Alexis M.A., Rumpel C., Knicker H., Leifeld J., Rasse D., Pechot N., Bardoux G., Mariotti A.
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Characteristics of a paleosol and its implication for the Critical Zone development, Rocky Mountain Front Range of Colorado, USA.
Applied Geochemistry, Vol. 26. 2011, Supplement, pp. S72-S75.
Leopold M., Völkel J., Dethier D., Huber J., Steffens M.
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Degradation of grass-derived pyrogenic organic material, transport of the residues within a soil column and distribution in soil organic matter fractions during a 28 month microcosm experiment.
Organic Geochemistry, Vol. 42. 2011, Issue 1, pp. 42-54.
Hilscher A., Knicker H.
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Fractionation of Organic Matter Due to Reaction with Ferrihydrite: Coprecipitation versus Adsorption. Environmental Science & Technology, Vol. 45. 2011, Issue 2, pp. 527–533.
Eusterhues K., Rennert T., Knicker H., Kögel-Knabner I., Totsche K.U., Schwertmann U.
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Clay fractions from a soil chronosequence after glacier retreat reveal the initial evolution of organo-mineral associations.
Geochimica et Cosmochimica Acta, Vol. 85. 2012, pp. 1-18.
Duemig A., Haeusler Werner, Steffens M., Koegel-Knabner I.
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Sensitivity of peatland carbon loss to organic matter quality.
Geophysical Research Letters, Vol. 39. 2012, Issue14, L14704.
Leifeld J., Steffens M., Galego-Sala A.
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Soil aggregate destruction by ultrasonication increases soil organic matter mineralization and mobility. Soil Science Society of America Journal, Vol. 76. 2012, No. 5, pp. 1634-1643.
Mueller C.W., Gutsch M., Schlund S., Prietzel J., Kogel-Knabner I.
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The role of lignin for the δ13C signature in C4 grassland and C3 forest soils. Soil Biology and Biochemistry, Vol. 57. 2013, pp. 1-13.
Duemig A., Rumpel C., Dignac M.-F., Koegel-Knabner I.
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Changes of litter chemistry and soil lignin signature during decomposition and stabilisation of 13C labelled wheat roots in three soil horizons. Soil Biology and Biochemistry, Vol. 67. 2013, pp. 55-61.
Baumann K., Sanaullah M., Chabbi A., Dignac M.-F., Bardoux G., Steffens M., Kögel-Knabner I., Rumpel, C.
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Desorption behaviour of polycyclic aromatic hydrocarbons after long-term storage of two harbour sludges from the port of Rotterdam, The Netherlands. Journal of Soils and Sediments, Vol. 13. 2013, Issue 6, pp. 1113–1122.
Heister K., Pols S., Loch J.P.G., Bosma T.N.P.
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Soil microbial diversity affects soil organic matter decomposition in a silty grassland soil. Biogeochemistry, Vol. 114. 2013, Issue 1–3, pp. 201–212.
Baumann K., Dignac M.F., Rumpel C., Bardoux G., Sarr A., Steffens M., Maron P.A.
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Bioavailability and isotopic composition of CO2 released from incubated soil organic matter fractions. Soil Biology and Biochemistry, Vol. 69. 2014, pp. 168-178.
Mueller CW, Gutsch M, Kothieringer K, Brüggemann N, Rethemeyer J, Leifeld J, Kögel-Knabner I
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Organic carbon accumulation on soil mineral surfaces in paddy soils derived from tidal wetlands. Geoderma, Vol. 228/229. 2014, pp. 90-103.
Wissing L., Kölbl A., Schad P., Bräuer T., Cao Z.H., Kögel-Knabner I.
