OPENAIRE OpenAire idUS. Depósito de Investigación de la Universidad de Sevilla. Sygma Recolector de Ciencia Abierta, RECOLECTA ZENODO DIGITAL.CSIC Crossref Europe PubMed Central PubMed Central European Union Open Data Portal https://pubs.acs.org/doi/pdf/10.1021/acs.est.3c01816 https://doi.org/10.1021/acs.est.3c01816 Environmental Science & Technology Open Access 2023-09-08 Dehesas are Mediterranean agro-sylvo-pastoral systems sensitive to climate change. Extreme climate conditions forecasted for Mediterranean areas may change soil C turnover, which is of relevance for soil biogeochemistry modeling. The effect of climate change on soil organic matter (SOM) is investigated in a field experiment mimicking environmental conditions of global change scenarios (soil temperature increase, +2-3 °C, W; rainfall exclusion, 30%, D; a combination of both, W+D). Pyrolysis-compound-specific isotope analysis (Py-CSIA) is used for C and H isotope characterization of SOM compounds and to forecast trends exerted by the induced climate shift. After 2.5 years, significant δ13C and δ2H isotopic enrichments were detected. Observed short- and mid-chain n-alkane δ13C shifts point to an increased microbial SOM reworking in the W treatment; a 2H enrichment of up to 40‰ of lignin methoxyphenols was found when combining W+D treatments under the tree canopy, probably related to H fractionation due to increased soil water evapotranspiration. Our findings indicate that the effect of the tree canopy drives SOM dynamics in dehesas and that, in the short term, foreseen climate change scenarios will exert changes in the SOM dynamics comprising the biogeochemical C and H cycles. 2. Zero hunger Take urgent action to combat climate change and its impacts Analytical pyrolysis Climate Change biomarkers nalyticalpyrolysis 15. Life on land Mediterranean soil Trees δ2H δ13C δ2H Soil Isotopes 13. Climate action Alkanes δ13C Climate change http://metadata.un.org/sdg/13 climatechange Biomarkers Pyrolysis San-Emeterio, Layla M., Zavala, Lorena M., Jiménez-Morillo, Nicasio T., Pérez-Ramos, Ignacio M., González-Pérez, José A., 2023-09-08 journalpaper Dehesas are Mediterranean agro-sylvo-pastoral systems sensitive to climate change. Extreme climate conditions forecasted for Mediterranean areas may change soil C turnover, which is of relevance for soil biogeochemistry modeling. The effect of climate change on soil organic matter (SOM) is investigated in a field experiment mimicking environmental conditions of global change scenarios (soil temperature increase, +2-3 °C, W; rainfall exclusion, 30%, D; a combination of both, W+D). Pyrolysis-compound-specific isotope analysis (Py-CSIA) is used for C and H isotope characterization of SOM compounds and to forecast trends exerted by the induced climate shift. After 2.5 years, significant δ13C and δ2H isotopic enrichments were detected. Observed short- and mid-chain n-alkane δ13C shifts point to an increased microbial SOM reworking in the W treatment; a 2H enrichment of up to 40‰ of lignin methoxyphenols was found when combining W+D treatments under the tree canopy, probably related to H fractionation due to increased soil water evapotranspiration. Our findings indicate that the effect of the tree canopy drives SOM dynamics in dehesas and that, in the short term, foreseen climate change scenarios will exert changes in the SOM dynamics comprising the biogeochemical C and H cycles. Effects of Climate Change on Soil Organic Matter C and H Isotope Composition in a Mediterranean Savannah (Dehesa): An Assessment Using Py-CSIA 10.1021/acs.est.3c01816 862695