Chemical composition and biological stability of pyrogenic C from a natural fire

2 pages, 1 figure, 3 references.-- Comunicación oral presentada en la Session 1. Pyrogenic C: Dstribution and Stability, en European Science Foundation-Exploratory Workshop, celebrado del 5-7 de noviembre 2013, en Sevilla, España.The work presented here is a synthesis of an article series conducted on natural charcoal in the environment (Alexis et al., 2007, Alexis et al. 2010, Alexis et al., 2012). The objective was to characterize the alteration of OM resulting from thermal alteration and to follow the fate of the produced pyrogenic C in soil.Peer reviewe

Editorial: Carbon storage in agricultural and forest soils

International audienc

Relating changes of organic matter composition of two German peats to climatic conditions during peat formation

Congreso celebrado del 2-7 mayo 2010, en Viena, Austria.Peatlands have been recognized as an important factor within the global C-cycle, since they store about one-third of the global terrestrial C-pool. Furthermore, peat deposits have the potential to record detailed paleoclimatic and – vegetational changes. They are formed in peculiar paleoecosystems where the slow biodegradation of plant residues depends on a series of pedo-climatic and hydromorphic factors leading to a progressive accumulation of organic matter stabilized in different evolutionary stages. Thus, its chemical composition should be applicable as a fingerprint of former prevailing environmental conditions and vegetation configurations. The aim of the present work was to identify this fingerprint in the cores of two German fens, one derived from the Havelland close to Berlin (Großer Bolchow) and the other derived from the alpine region of Bavaria (Kendlmühlfilzen) by investigating the organic matter transformation as a function of peat depths.Peer reviewe

Soil carbon dynamic associated to land-use changes in semi-arid forests of Argentina

Fil: Conti, G. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Conti, G. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Baptist, F. Biotope; Francia.Fil: Rumpel, C. Centre national de la recherche scientifique; Francia.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Land-use change represents one of the main drivers of global climatic change, affecting the amount and quality of organic matter (OM) in soils worldwide. A reduction in the amount of biomass due to forest management is expected to affect both the amount of new OM going into the soil and its microbial decomposability due to changes in soil environmental conditions. These changes should impact soil microbial communities, their activity and decomposition rates, affecting the amount and quality of organic carbon (OC) remaining in the soil. In order to obtain information on the effect of land-use change on the OM quantity and quality, its origin and its degree of stabilization (i.e., microbial decomposability), we characterized the amount of OC, the lignin and polysaccharide compounds by wet chemical analysis, as well as basal respiration rates across a disturbance gradient (n=20) in a semiarid Chaco forest of central Argentina. Disturbance reduced the amount and quality of litterfall, reflected in a reduction in SOM content. Soil carbohydrates content followed the same trend but lignin was not affected by land-use change. Although basal CO2 effluxes showed the same pattern than SOM content, when normalized per OC content, they showed the opposite trend, with higher CO2 released per C in sites with lower OC and carbohydrates content. Our results support the idea that in the semi-arid Chaco forest, chemically labile compounds are more vulnerable to disturbance, but also that OM could be protected and stabilized regardless of its chemical identity.Fil: Conti, G. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Conti, G. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Kowaljow, E. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Baptist, F. Biotope; Francia.Fil: Rumpel, C. Centre national de la recherche scientifique; Francia.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Cuchietti, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Multidisciplinario de Biología Vegetal; Argentina.Fil: Díaz, S. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Departamento de Diversidad Biológica y Ecología; Argentina.Ecologí

Role of Nanoclays in Carbon stabilization in Andisols and Cambisols

Greenhouse gas (GHG) emissions and their consequent effect on global warming are an issue of global environmental concern. Increased carbon (C) stabilization and sequestration in soil organic matter (SOM) is one of the ways to mitigate these emissions. Here we evaluated the role of nanoclays isolated from soil on C stabilization in both a C rich Andisols and C depleted Cambisols. Nanoclays were analyzed for size and morphology by transmission electron microscopy, for elemental composition and molecular composition using pyrolysis-GC/MS. Moreover, nanoclays were treated with H2O2 to isolate stable SOM associated with them. Our result showed better nanoclay extraction efficiency and higher nanoclay yield for Cambisol compared to Andisols, probably related to their low organic matter content. Nanoclay fractions from both soils were different in size, morphology, surface reactivity and SOM content. Nanoclays in Andisols sequester around 5-times more C than Cambisols, and stabilized 6 to 8-times more C than Cambisols nanoclay after SOM chemical oxidation. Isoelectric points and surface charge of nanoclays extracted from the two soils was very different. However, the chemical reactivity of the nanoclay SOM was similar, illustrating their importance for C sequestration. Generally, the precise C stabilization mechanisms of both soils may be different, with nanoscale aggregation being more important in Andisols. We can conclude that independent of the soil type and mineralogy the nanoclay fraction may play an important role in C sequestration and stabilization in soil-plant systems

Comparison of CuO oxidation, analytical pyrolysis and IR spectroscopy to study the lignin signature in soil humic acids

2 pages, 1 figure, 4 references.-- Póster presentado al citado congreso en la Sesión II: Soil (S) Nº 496.-- Book of Abstracts of the Communications presented to the 26th International Meeting on Organic Geochemistry (IMOG), held in Costa Adeje, Tenerife – Spain, September 15 – 20, 2013.One of the most common methodologies in the study of lignins in soils is alkaline CuO oxidation [1]. This method allows quantification of the released lignin-derived phenols, however, it is time-consuming and requires previous derivatization before GC. In order to compare the information on lignin composition provided by current routine techniques used on soil humic acids (HA), this research compares molecular assemblages obtained from 16 HA samples by using either CuO degradation, or analytical pyrolysis (Py), as well as a nondestructive technique such as infrared (IR) spectroscopy.Peer reviewe