Climate variability in Mediterranean ecosystems is reflected by soil organic matter pyrolytic fingerprint
Soil organic matter (SOM) is a major component of the biogeochemical cycle contributing to soil general properties and conservation. The progressive depletion of the SOM in Mediterranean ecosystems results in an increased advance of desertification. The SOM not only plays a crucial role in soil resi...
| Autores: | , , , , |
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| Formato: | artículo |
| Fecha de publicación: | 2020 |
| País: | España |
| Recursos: | Universidad Autónoma de Madrid |
| Repositorio: | Biblos-e Archivo. Repositorio Institucional de la UAM |
| Idioma: | inglés |
| OAI Identifier: | oai:repositorio.uam.es:10486/695764 |
| Acesso em linha: | http://hdl.handle.net/10486/695764 https://dx.doi.org/10.1016/j.geoderma.2020.114443 |
| Access Level: | acceso abierto |
| Palavra-chave: | Analytical pyrolysis Emberger index Partial least squares regression Soil organic matter Geología |
| Resumo: | Soil organic matter (SOM) is a major component of the biogeochemical cycle contributing to soil general properties and conservation. The progressive depletion of the SOM in Mediterranean ecosystems results in an increased advance of desertification. The SOM not only plays a crucial role in soil resilience, but also represents a repository of environmental information on soil forming factors in particular climatic constraints. In this research, analytical pyrolysis (Py-GC/MS) is used to study SOM composition in 30 soils under contrasting bioclimatic scenarios as defined by the classical Emberger (Q) index. Partial least squares (PLS) regression using the major pyrolysis compounds as descriptors allowed to predict (P < 0.05) Q indexes, and provide molecular proxies of climatic variability effects on SOM composition. In addition, pyrolytic compound assemblages from soils developed under extreme climatic conditions were compared using a graphical approach based on surface density plots built from the major 193 pyrolysis compounds represented in the plane defined by their H/C and O/C atomic ratios. The differences between the proportions of the individual pyrolysis compounds in terms of the bioclimatic scenarios were also illustrated by a simulation of SOM molecular composition under extreme conditions of aridity or wetness. Although no cause-to-effect is inferred, the results show that SOM composition retains environmental information on the Q index. This is mainly related with the total abundances of methoxyphenols and alkylbenzene compounds, suggesting that the degree of transformation of SOM could be related with the variable accumulation of microbial and plant biomass controlled by climatic factors which is a potential field for future research |
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