Search

10 páginas.- 4 figuras.- 1 tablas.- referencias., [EN]: There is a need for tools to determine the origin of organic matter (OM) in Blue Carbon Ecosystems (BCE) and marine sediments to (1) facilitate the implementation of Blue Carbon strategies into carbon accounting and crediting schemes and (2) decipher changes in ecosystem condition over decadal to millennial time scales and thus to understand and predict the stability of BCE in a changing world. Pyrolysis-GC-compound specific isotope analysis (Py-CSIA) is applied for the first time in marine environments and BCE research. We studied Australian mangrove, tidal marsh and seagrass sediments, in addition to potential sources of OM (Avicennia, Posidonia, Zostera, Sarcocornia, Ecklonia and Ulva species and seagrass epiphytes), to identify precursors of different biomacromolecule constituents (lignin, polysaccharides and aliphatic structures). Firstly, the link between bulk δ13C and δ13C reconstructed from compound-specific δ13C showed that the pyrolysis approach allows for the isotopic screening of a representative portion of the OM. Secondly, for all samples, the C isotope fingerprint of the carbohydrate products (plant polysaccharides) was the heaviest (13C enriched), followed by lignin and aliphatic products. The differences in δ13C among macromolecules and the overlap in δ13C among putative sources reflect the limitations of bulk δ13C analyses for deciphering OM provenance. Thirdly, phanerogams specimen had the heaviest carbohydrate and lignin, confirming that seagrass-derived lignocellulose can be traced based on δ13C. Consistent differences for individual compounds were identified between seagrasses and between Avicennia and Sarcocornia using Py-CSIA. Fourth, ecosystem shifts (colonization of seagrass habitats by mangrove) on millenary time scales, hypothesized in previous studies on the basis of bulk δ13C and Py-GC–MS, were confirmed by Py-CSIA. We conclude that Py-CSIA is useful in Blue Carbon research to decipher OM sources in marine sediments, identify ecosystem transitions in palaeoenvironmental records, and to understand the role of different OM compounds in Blue Carbon storage., [ES]: Es necesario desarrollar herramientas para determinar el origen de la materia orgánica (MO) en ecosistemas de “Blue Carbon” (BCE) y en sedimentos marinos para (1) facilitar el desarrollo de estrategias de “Blue Carbon” en los esquemas de contabilidad y acreditación de C (2) descifrar cambios en las condiciones del ecosistema a escala de décadas a milenios y, por lo tanto, comprender mejor y predecir la estabilidad de BCE en escenarios de cambio climático. En este trabajo, aplicamos por primera vez el análisis de isótopos estables de C en compuestos específicos liberados por pirolisis (Py-CSIA) en entornos marinos y en la investigación de BCE. Estudiamos sedimentos de manglares, marismas y praderas marinas de Australia, además de las fuentes potenciales de MO (especies de Avicennia, Posidonia, Zostera, Sarcocornia, Ecklonia y Ulva y epífitas de praderas marinas), para identificar precursores de los diferentes constituyentes de las principales biomacromoléculas (lignina, polisacáridos y estructuras alifáticas). En primer lugar, la relación encontrada entre el δ13C total y el reconstruido a partir de los δ13C específicos de los compuestos, indica que el enfoque de pirólisis permite el cribado isotópico de una parte representativa de la MO. En segundo lugar, para todas las muestras, la huella isotópica de C de los productos de carbohidratos (polisacáridos vegetales) fue la más pesada (enriquecida en 13C), seguida de la lignina y los productos alifáticos. Las diferencias en δ13C entre los distintos tipos de macromoléculas y la superposición en δ13C entre las distintas fuentes putativas, pone de manifiesto las limitaciones de los análisis convencionales de δ13C totales (“bulk”) para descifrar la procedencia de la MO. En tercer lugar, las fanerógamas estudiadas mostraron la mayor proporción de carbohidratos y lignina, lo que confirma que la lignocelulosa derivada de pastos marinos se puede rastrear en base al δ13C de compuestos específicos. Mediante la Py-CSIA se identificaron diferencias consistentes para compuestos individuales entre las especies de praderas marinas y entre las de manglar (Avicennia y Sarcocornia). En cuarto lugar, mediante la Py-CSIA de δ13C confirmamos cambios en el ecosistema costero (colonización de hábitats de praderas marinas por manglares) ocurridos en los últimos milenios. Concluimos que la Py-CSIA es útil en la investigación de “Blue Carbon” y para descifrar las distintas fuentes de MO en los sedimentos marinos, identificar transiciones de ecosistemas en registros paleoambientales y para comprender mejor el papel de diferentes compuestos de la MO en el almacenamiento de C en el BCE., O.S. was supported by I+D+i projects RYC2019-027073-I and PIE HOLOCENO 20213AT014 funded by MCIN/AEI/10.13039/501100011033 and FEDER. L.M.S.-E. thanks MINECO pre-doctoral FPI fellowship BES-2017-079811 and J.A.G.-P. project PAIDI2020, PY20_01073. Both projects co-funded with EU FEDER funds. The laboratory personnel Alba M. Carmona and Desiré Monis are acknowledged for technical assistance. We are grateful to the anonymous reviewers for their effort and comments.

10 páginas.- 6 figuras.- 5 tablas.- 49 referencias, A field experiment was conducted on the Andalusian coast (Granada, Southern Spain) to study the time course of nutrient release into the soil after the addition of bagged pruning waste from subtropical orchard trees (avocado, cherimoya, and mango) and urban garden waste over three two-year periods. N, P, and K concentrations were greater in the garden waste, whilst avocado and cherimoya pruning waste registered the highest values for Mg. In general, micronutrient contents were low in all waste, especially Cu. Macronutrient release followed a three-phase dynamic: fast initial release, intermediate stabilization, and final increase. Garden waste showed a similar time course in all three trees and released greater concentrations of K and P. The annual decomposition rate factor k was negative for N and Ca in the avocado tree, indicating strong biological activity in this plot. Avocado, cherimoya, and garden waste showed a good microbial degradation, improving soil quality by increasing carbon and nitrogen contents as well as soil microbial activity. As for the mango tree, its special microclimatic conditions appeared to favor waste photodegradation, thus eliminating nutrients that were not incorporated into the soil. Soil enzymatic activities increased in the avocado and cherimoya trees with the addition of all waste. In the mango tree, only an increase in urease was detected after the addition of garden waste. Our results suggest that the time course of organic waste in different subtropical trees grown on similar soils is significantly conditioned by the microclimatic characteristics. © 2021 by the authors. Licensee MDPI, Basel, Switzerland., Funding: Authors appreciate the financial support of this work by the Spanish Ministry of Economy and Competitiveness (Project CGL-2013-46665-R) and the European Regional Development Fund (ERDF).

9 páginas.- 5 figuras.- 1 tabla.- referencias.- Supplementary data to this article can be found online at https://doi.org/10.1016/j.scitotenv.2022.159288, Mediterranean savannahs (dehesas) are agro-sylvo-pastoral systems with a marked seasonality, with severe summer drought and favourable rainy spring and autumn. These conditions are forecasted to become more extreme due to the ongoing global climate change. Under such conditions, it is key to understand soil organic matter (SOM) dynamics at a molecular level. Here, analytical pyrolysis (Py-GC/MS) combined with chemometric statistical approaches was used for the molecular characterization of SOM in a five-years field manipulative experiment of single and combined rainfall exclusion (drought) and increased temperature (warming). The results indicate that SOM molecular composition in dehesas is mainly determined by the effect of the tree canopy. After only five years of the climatic experiment, the differences caused by the warming, drought and the combination of warming+drought forced climate scenarios became statistically significant with respect to the untreated controls, notably in the open pasture habitat. The climatic treatments mimicking foreseen climate changes affected mainly the lignocellulose dynamics, but also other SOM compounds (alkanes, fatty acids, isoprenoids and nitrogen compounds) pointing to accelerated humification processes and SOM degradation when soils are under warmer and dryer conditions. Therefore, it is expected that, in the short term, the foreseen climate change scenarios will exert changes in the Mediterranean savannah SOM molecular structure and in its dynamic., Projects EU-EJC 2nd Call Projects MIXROOT-C and MAXROOT-C, Ministerio de Ciencia Innovación y Universidades (MICIU) INTERCARBON project (CGL2016-78937-R) & DECAFUN (CGL2015-70123-R). L. M. San Emeterio also thanks MICIU for funding FPI research grants (BES-2017-07968).

13 páginas.- 4 figuras.- 2 tablas.- referencias.- Supplementary data to this article can be found online athttps://doi.org/10.1016/j.scitotenv.2021.151572, This study aims to evaluate the effects of technosols made with different organic amendments to restore degraded soils in a semiarid limestone quarry. The effects on soil quality, functionality and organic matter dynamics of the technosols amended with waste of gardening, greenhouse horticultural, stabilized sewage sludge and two mixtures of sludge with both vegetable composts were assessed. Several physical and chemical properties, humus fractions, soil respiration and molecular composition was performed after 6 and 18 months. Un-amended soils, and nearby natural undegraded soils served as reference. Amended technosols increased water retention capacity, electrical conductivity, total organic carbon and nitrogen, respect to not amended and natural soils. Humus fraction composition was not altered over time. Un-amended soils, very poor in organic matter, did not show any pyrolyzable compounds or labile soil organic matter by thermogravimetry. In contrast, the pyrochromatograms of natural soils showed lignocellulosic materials, polypeptides and a noticeable presence of alkylic compounds. In technosols with both types vegetable compost, the organic matter structure was more complex, showing compounds from lignin-derived and long-chain alkyl, polysaccharides, chlorophyll isoprenoids and nitrogen. In sludge technosol, a set of sterols was outstanding. The mixtures showed a molecular fingerprint of materials derived from the decomposition of the organic amendments that formed them. These signs of the contribution of different organic matter forms derived from the amendments were also reported by the series exothermic peaks found in the calorimetry. This short-term study indicates a clear effect of the amendments on the recovery of soil organic matter and presumably of its functionality. After the amendments application, microbial activity and soil respiration rates increased rapidly but ceased 18 months later. The molecular composition of the organic matter of the soils amended with plant compost was very similar to that of natural, non-degraded soils in nearby areas., This work was supported by the Spanish Ministry of Economy and Competitiveness (MINECO), and FEDER funds, through the project CGL2017-88734-R (BIORESOC) MINECO/AEI/FEDER, UE and FEDER-Junta de Andalucía Research Projects RESTAGRO (UAL18-RNM-A021-B), MarkFire (PAIDI2020, PY20_01073) and Restoration of Abandoned Agricultural Soils in Semiarid Zones to Improve Productivity and Soil Quality and Enhance Carbon Sequestration (P18-RT-4112). Isabel Miralles is grateful for funding received from the Ramón y Cajal Research Grant (RYC-2016-21191) from the Spanish Ministry of Economy and Competitiveness (MINECO), Raúl Ortega thanks his postdoctoral contract HIPATIA of the University of Almería Research Plan. Layla M. San Emeterio thanks the pre-doctoral FPI fellowship (grant number BES-2017-079811).

16 págs.- 5 figuras.- 3 tablas.- 76 referencias.- The following are available online at https://www.mdpi.com/article/10.3390/app11156684/s1 .- (This article belongs to the Special Issue Composts and Organic Wastes: Analytical Methods and Applications), An innovative approach based on the combination of analytical pyrolysis coupled with gas chromatography-mass spectrometry (Py-GC/MS) with compound-specific isotope analysis (Py-CSIA) is used to study the composting process of maize biomass. This multidisciplinary approach aims to elucidate the decomposition rate of the main biogenic materials (lignin, cellulose, proteins, lipids, and waxes) responses to the composting process. According to Py-GC/MS data/structural composition, a noticeable and significant decrease during the first stage of the composting process of carbohydrates and aromatic compounds is found, followed by a gradual increase of all compounds till the end of the experiment. This trend, along with an increase of fatty acids methyl-ester at the first composting stage, sustains the microbial activity and its stabilization over time. Py-CSIA data showed a significant enrichment in 13C in all identified compounds over time, supporting the semi-quantitative results and the decomposition of initial biomass throughout the composting process. This trend is also perceptible in lignin moieties, long-chain aliphatic structures, and isoprenoids, as highly recalcitrant compounds, presumably due to depolymerization and carbon translocation of side-chain molecules during the composting process. Compound-specific isotope values showed a good correlation with the bulk isotope data, and this served as validation of the technique. However, bulk values showed higher heterogeneity because those represent an average of all organic compounds in the sample. By combining isotopic and structural information using Py-GC/MS and Py-CSIA, we are able to provide further information and a more detailed approach to the study of the decomposition process of biomass by considering the diverse dynamics of the main biogenic compounds., This research was funded by the Spanish Ministry of Economy and Competitiveness (MINECO) with the pre-doctoral FPI fellowship (grant number BES-2017-079811) to L.M.S.-E. and by Junta de Andalucía project MarkFire (PAIDI2020, PY20_01073). Both projects are co-funded with EU FEDER funds.

12 páginas. 4 figuras.- 2 tablas.- 70 referencias.- Additional supporting information may be found in the online version of this article at http://onlinelibrary.wiley.com/doi/ 10.1002/ecy.2936/suppinfo .- Data are available from the Dryad Digital Repository: https://doi.org/10.5061/dryad.59zw3r23d, Recent studies have shown that invasive earthworms can dramatically reduce native biodiversity, both above and below the ground. However, we still lack a synthetic understanding of the underlying mechanisms behind these changes, such as whether earthworm effects on soil chemical properties drive such relationships. Here, we investigated the effects of invasive earthworms on soil chemical properties (pH, water content, and the stocks and fluxes of carbon, nitrogen, and phosphorus) by conducting a meta‐analysis. Invasive earthworms generally increased soil pH, indicating that the removal of organic layers and the upward transport of more base‐rich mineral soil caused a shift in soil pH. Moreover, earthworms significantly decreased soil water content, suggesting that the burrowing activities of earthworms may have increased water infiltration of and/or increased evapotranspiration from soil. Notably, invasive earthworms had opposing effects on organic and mineral soil for carbon and nitrogen stocks, with decreases in organic, and increases in mineral soil. Nitrogen fluxes were higher in mineral soil, whereas fluxes in organic soil were not significantly affected by the presence of invasive earthworms, indicating that earthworms mobilize and redistribute nutrients among soil layers and increase overall nitrogen loss from the soil. Invasive earthworm effects on element stocks increased with ecological group richness only in organic soil. Earthworms further decreased ammonium stocks with negligible effects on nitrate stocks in organic soil, whereas they increased nitrate stocks but not ammonium stocks in mineral soil. Notably, all of these results were consistent across forest and grassland ecosystems underlining the generality of our findings. However, we found some significant differences between studies that were conducted in the field (observational and experimental settings) and in the lab, such as that the effects on soil pH decreased from field to lab settings, calling for a careful interpretation of lab findings. Our meta‐analysis provides strong empirical evidence that earthworm invasion may lead to substantial changes in soil chemical properties and element cycling in soil. Furthermore, our results can help explain the dramatic effects of invasive earthworms on native biodiversity, for example, shifts towards the dominance of grass species over herbaceous ones, as shown by recent meta‐analyses., This project received support from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement 677232). Further support came from the German Centre for Integrative Biodiversity Research (iDiv) Halle-Jena-Leipzig, funded by the German Research Foundation (FZT 118).

5 páginas.- 3 figuras. 4 referencias, Los lípidos del suelo son sustancias de origen vegetal o microbiano, insolubles en agua y solubles en disolventes orgánicos. Esta fracción orgánica incluye biomarcadores asociados a diferentes comunidades microbianas y proporciona información sobre la dinámica de la materia orgánica del suelo (MOS) y de los intercambios de carbono. En este trabajo presentamos los resultados preliminares obtenidos en un experimento de marcaje isotópico natural en un suelo agrícola mediterráneo de la estación experimental "La Hampa" (Sevilla), sometido a rotación de cultivos trigo (C3)-maíz (C4). La fracción lipídica del suelo se estudia a distintas profundidades mediante cromatografía de gases acoplada a espectrometría de masas (GC-MS) y su composición isotópica de carbono (δ13C) se determinó en compuestos los años de cambio a cultivo de maíz y de aportes de su biomasa al suelo, se encontró un enriquecimiento significativo de δ13C (c. 2 ‰) para los FAME saturados C20, C22 y C23 y el monoinsaturado FAME C22:1 y de hasta 5 ‰ en alcanos C29 y C31. No se encontraron diferencias significativas para los alcoholes e hidroxiácidos. Estos cambios isotópicos pueden deberse a una mayor especificidad de los alcanos de cadena larga de origen vegetal, mientras que los otros compuestos son menos específicos y pueden tener un origen diverso. No se observaron diferencias significativas en la composición isotópica de la MOS a las diferentes profundidades del suelo dentro de un mismo tratamiento. Todo ello, junto al bajo contenido en materia orgánica (MO) que se mantiene constante a pesar de la cantidad de biomasa C4 agregada durante el cultivo, apunta a altas tasas de mineralización y a una rápida transformación de los restos vegetales en estos suelos agrícolas mediterráneos., Se agradece al MINECO y al Fondo Europeo de Desarrollo Regional (FEDER) la financiación del proyecto CGL2016-78937-R. A Desiré Monis Carrere por la asistencia técnica en laboratorio

7 páginas.- 4 figruas. 5 tablas.- 32 referencias.- Supplementary material related to this article can be found, in the online version, at doi:https://doi.org/10.1016/j.scienta.2019.109120, Cherimoya, a tropical fruit from South America whose commercial demand is increasing for both its exceptional flavor and high nutritional content, is expanding in cultivation to subtropical areas such as the Mediterranean coast of Andalusia (Spain). In this paper, we analyze cherimoyas (peel, pulp, and seed) grown in Almunecar (Granada, Spain) during the years 2013, 2015, and 2016 from trees applied with different pruning wastes (avocado, cherimoya, mango, and garden). The cherimoya fruits had high contents in most of the macronutrients, especially K, Ca, and micronutrients such as Fe and Zn. The Na, P, K and Ca concentrations were related to the plant mulch that released nutrients to the soil and led to a variation in soil-nutrient bioavailability by decreasing the soil pH. The seed was the part of the cherimoya that registered the least nutritional change due to annual weather differences and the highest positive effects of mulching in terms of increased nutrient availability after mulching., Authors appreciate the financial support of this work by the Spanish Ministry of Economy and Competitiveness (Project CGL-2013-46665-R) and the European Regional Development Fund (ERDF).

Comunicación oral presentada en el 1st Iberian Meeting in Separation Sciences & Mass Spectrometry, XIX Conference of the Spanish Society of Chromatography and Related Techniques (SECyTA), IX Conference of the Spanish Society of Mass Spectrometry (SEEM), VI Conference of the Mass Spectrometry Group of the Portuguese Society of Chemistry (SPQ). Santiago de Compostela, October 8th-11th (2019)., Changes in climatic and environmental conditions can affect both, plant chemical and isotope composition. Nowadays, many studies use bulk isotope values, which represent a weighed mean average of the different plant compounds. An isotopic characterization of individual biogeochemical compounds is desirable in order to differentiate the isotopic composition of the main plant components. However, biomass is composed mainly of high MW biopolymers i.e. polysaccharides (celluloses), polypeptides (lignin), polypeptides (proteins), polyesters (waxes), etc. not amenable to most chromatographic techniques without the use of more or less previous intense extraction and sample preparation. Here, a particular analytical pyrolysis technique combining Py‐GC with a continuous flow isotope ratio mass spectrometer (IRMS) (Py‐CSIA) is described and validated. Isotopic values obtained by Py‐CSIA of standard n‐alkanes mixtures (dissolved C16 to C30 series with increasing concentrations along three pentads, Indiana Univ. SIL mix. Type B), fitted well to a straight line (R2 > 0.999). No induced thermal cracking nor deviations from the acclaimed isotope composition (fractionation) was observed up to high pyrolysis temperature (< 400 °C). Results linking detailed molecular and isotope composition obtained by the direct analysis of various biomass types and biopolymers will be discussed. In general, our results show that Py‐ CSIA can reveal major differences between biomass components from different biogenic origin with high precision. In addition, despite that biomass pyrolysates from different origins may yield very similar Py‐GC/MS patterns, Py‐CSIA can make the difference providing additional valuable isotopic information., Ministerio de Ciencia Innovación y Universidades” INTERCARBON project (CGL2016‐78937‐R). N.T. Jiménez‐Morillo and L. San Emeterio thanks the MICIU for funding FPI research grants (BES‐2013‐062573 and Ref. BES‐2017‐07968). Desiré Monis is acknowledged for technical assistance

Póster presentado en el 1st Iberian Meeting in Separation Sciences & Mass Spectrometry, XIX Conference of the Spanish Society of Chromatography and Related Techniques (SECyTA), IX Conference of the Spanish Society of Mass Spectrometry (SEEM), VI Conference of the Mass Spectrometry Group of the Portuguese Society of Chemistry (SPQ). Santiago de Compostela, October 8th-11th (2019)., In less than 50 years the area occupied by peat bogs in the Gulf of Cádiz (SW‐Spain) has been reduced by more than 90%. The peat bog studied here may well be considered as relict and one of the last and more Meridional still in existence in the Northern hemisphere. The vertical molecular composition of a 85 cm peat bog from Ribetehilo lagoon (Doñana National Park; SW‐Spain 37° 7'30.81"N; 6°37'50.19"O) is studied using analytical pyrolysis (Py‐GC/MS) and ultra‐high resolution mass spectrometry (ESI‐FT‐ICR/MS). The results obtained by the two techniques were similar, showing as shallow OC composition was dominated by fresh material from upper vegetation cover, while more transformed and humified material was accumulated in the bottom layers. This may be due to i) intense microbial activity combined with large fluctuations of the water table occurring during the year; and/or ii) anaerobic rocesses. In general, the lack of peat preservation in depth is probably a sign of bog degradation processes, probably linked with climate changes to which Mediterranean wetlands are particularly responsive., MICIU INTERCARBON Project (CGL2016‐78937‐R UE/FEDER). N.T. Jiménez‐Morillo and L. San Emeterio thanks the MICIU for funding FPI research grants (BES‐2013‐062573 and Ref. BES‐2017‐07968 UE/FEDER). Prof. P. Hatcher (Old Dominion Univ., USA) for advice and access to the COSMIC ESI‐FT‐ICR/MS instrument. Desiré Monis for technical assistance.

Póster presentado en EGU 2019, Viena (Austria) 7 al 12 de abril de 2019. Puede ver el Abstract en https://meetingorganizer.copernicus.org/EGU2019/EGU2019-17244.pdf, Castañar cave (Cáceres, Spain) characteristically contains a series of Mg-Si phases forming fibres and films associated to aragonite, magnesite, huntite and spheroidal dolomite in moonmilk, which form coatings and crust speleothems. These Mg-Si phases consist of kerolite, sepiolite and its admixtures. Under scanning electron microscope kerolite appears as colloform, smooth masses or films. Sepiolite mostly occurs as isolated fibres 50 to 200 nm thick and up to 50 µm long and mats of interwoven fibres of several shapes, which often look like jelly, flexible-like films. Both minerals are highly hydrated and with low crystallinity. In order to evaluate a possible role of organic matter in the biogeochemical formation of these minerals, two samples of moonmilk and 4 controls were analyzed by analytical pyrolysis (Py-GC/MS). The pyrolizate of the samples consisted mainly of a) methoxyl-lacking benzenes, b) unsaturated and saturated hydrocarbons, c) polycyclic aromatic and d) hydroaromatic hydrocarbons. This chemical assemblage is not compatible with a recent biogenic origin of the organic matter in the moonmilk. This is suggested by the small proportions of fatty acids in addition to the lack of nitrogen- and carbohydrate-derived compounds. In fact, most of the aromatic compounds (e.g., phenols and catechols) which would be expected from plant or microbial biomass were in negligible proportions whereas methoxyphenols (typical lignin-derived compounds) were completely absent, suggesting no contribution from biomass of vascular plants. Conversely, the signature of alkyl compounds found in these samples (homologous series) is compatible with that in coals, kerogens or other forms of fossil organic matter. In particular, the whole pyrograms resembled the control shale from the host rock, which suggests that the organic matter was in fact inherited from the host rocks. Concerning the mineral phase, the low crystallinity and textures of kerolite and sepiolite indicate formation by direct precipitation in the cave waters via recrystallization of a gel precursor, under specific local conditions of high alkalinity and activity of Mg and Si. In conclusion, the low amount of organic matter content and its molecular composition, in addition to the lack of clear organic features and the general context indicates that kerolite and sepiolite precipitation in Castañar cave was most probably abiotic.

Póster presentado en EGU 2019, Viena (Austria) 7 al 12 de abril de 2019. Puede ver el Abstract en https://meetingorganizer.copernicus.org/EGU2019/EGU2019-17062.pdf, Given the artistic, social and economic value of cultural heritage, its conservation is of upmost importance for being preserved for future generations. Through accurate characterization of organic materials, such as alteration products and biopolymers used in the past as construction, supporting or protective materials of in monuments and artistic artifacts, it would be possible to ameliorate the conservation practices for controlling deterioration. Pyrolysis-compound specific isotope analysis (Py-CSIA) is a novel analytical technique able to provide, not only an accurate identification of organic compounds in different complex matrices, but also additional valuable information about nature and origin of the materials based on their isotopic composition. This technique is based on the coupling of a micro-furnace pyrolyser (F.Lab 3030i) to a gas chromatograph (GC) and using an isotope ratio mass spectrometer (IRMS) as detector. The individual volatile pyrolysis products separated by gas chromatography are directed to a combustion or a pyrolysis micro-reactor (GC-Isolink system) and finally the isotope composition of the gases produced measured in the IRMS (Thermo Fisher Delta V Advantage) via an appropriate interface (ConFlo IV universal interface unit). With this technique it is possible to make direct measures of stable isotope ratios (i.e. [U+1D6FF]13C, [U+1D6FF]D, , [U+1D6FF]15N and also [U+1D6FF]18O) of specific compounds with minimum sample handling. In this communication we will introduce the Py-CSIA technique in the field of cultural heritage as a novel technique for the direct determination of the isotopic composition of polymers and biopolymers. Case studies on the characterization of biopolymers using Py-CSIA will be presented and the potential application in the field of cultural heritage conservation discussed., [1] González‐Pérez et al. (2016). Compound‐specific stable carbon isotopic signature of carbohydrate pyrolysis products from C3 and C4 plants. Journal of the Science of Food and Agriculture, 96(3), 948-953. [2] González-Pérez et al.. (2015). Pyrolysis-gas chromatography–isotope ratio mass spectrometry of polyethylene. Journal of Chromatography A, 1388, 236-243. [3] Gil et al. (2011). Stable isotopes and human diet in central western Argentina. Journal of Archaeological Science, 38(7), 1395-1404. [4] Mottram et al.. (1999). New chromatographic, mass spectrometric and stable isotope approaches to the classification of degraded animal fats preserved in archaeological pottery. Journal of Chromatography A, 833(2), 209-221. [5] Tambakopoulos, D., & Maniatis, Y. (2017). The marble of the Cyclades and its use in the Early Bronze Age. Early cycladic sculpture in context. Oxbow: Oxford and Philadelphia, 468-82. [6] von Holstein, I. C., & Makarewicz, C. A. (2016). Geographical variability in northern European sheep wool isotopic composition (δ13C, δ15N, δ2H values). Rapid Communications in Mass Spectrometry, 30(12), 1423-1434., This research has been funded by the Spanish Gov. ‘Ministerio de Ciencia , Innovación y Universidades’ under grant ref. BES–2017–079811 . Project CGL 2016 -78937 –Co-financed by FEDER Funds .

Comunicación oral presentada en EGU 2019, Viena (Austria) 7 al 12 de abril de 2019. Puede ver el Abstract en https://meetingorganizer.copernicus.org/EGU2019/EGU2019-18932-1.pdf, Changes in climatic and environmental conditions can affect both, plant chemical and isotope composition. Therefore, biomass carbon isotope composition is frequently used to gain information about the environmental conditions at the time a plant was growing [1]. In this field, the majority of studies use isotope values obtained from bulk samples. However, these values are a weighed mean average of the different plant compounds. The Isotopic characterization of individual biogeochemical compounds represents a relevant analytical advance able to differentiate the isotopic composition of the main plant components i.e. polysaccharides, lignin, polypeptides, lipids and waxes, etc. Here, we investigate the link between molecular and isotope composition of bark from three Eucalyptus species (E. grandis, E. dunni and a hybrid E. grandis x E. dunni) using Py-CSIA. Bulk samples and lignin extracted were analysed by Py-CSIA; this technique, although not widely used, has been previously developed and applied, with different variants [2-7], to characterize plant products including lignin [8], sugars [9] and terpenes [10]. Our results support the idea that the pyrolysis compound specific isotope analysis (Py-CSIA) can provide valuable and accurate isotopic fingerprinting of biomass. Despite that wood/bark from different origins provide very similar pyrolysis pattern, isotopic composition of relevant specific compounds can make the difference giving additional valuable information., [1] Michenerand Lajtha (Eds). Stable Isotopes in Ecology and Environmental Science (2nd Ed.) Blackwell Publishing Ltd (2007) 566p. [2] Gonñi and Eglinton, J. High Resol. Chromat. 17 (1994), 476. [3] Pulchan et al., J. Anal. Appl. Pyrolysis 42 (1997), 135. [4] Gleixner and Schmidt. In Nitrogen-containing Macromolecules in the Bio- and Geosphere. Stankiewicz and van Berger (Eds), ACS Symposium Series 707 (1998), pp. 34–46. [5] Gleixner et al. Rapid Commun. Mass Spectrom. 13 (1999) 1278. [6] Schulten and Gleixner Water Res. 33 (1999) 2489. [7] Gleixner et al. Organic Geochemistry 33 (2002) 357. [8] Steinbeiss et al. J. Anal. Appl. Pyrolysis 75 (2006) 19. [9] González-Pérez et al. J. Sci. Food Agric. 96 (2016) 948. [10] Llana-Ruíz-Cabello et al. J. Chrom A 1525 (2017) 145., FPI grant funded by the Spanish Government (Ref. BES-2017-07968)