Gonzalo Almendros

Gonzalo Almendros
Spanish National Research Council | CSIC · Departamento de Biogeoquímica y Ecología Microbiana

PhD

About

286
Publications
51,965
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
8,384
Citations
Citations since 2017
45 Research Items
2645 Citations
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
20172018201920202021202220230100200300400
Introduction
Gonzalo Almendros currently works at the Departament of Biogeochemistry and Microbial Ecology, National Museum of Natural History. Spanish National Research Council. The current project is 'New Methodological Approaches for the Computational Screening of Environmental Proxies from structural Research of soil and sedimentary Organic Matter.
Additional affiliations
April 2006 - June 2016
Spanish National Research Council
Position
  • Professor

Publications

Publications (286)
Article
Full-text available
The increasing land degradation is a problem that affects many soils in countries with a Mediterranean climate. In this aspect the soil organic matter (SOM) plays an important role, due to its progressive biodegradation parallels to desertification and the concomitant emissions of CO 2 to the atmosphere. These facts make basic research on the struc...
Article
Full-text available
Purpose The transformation of extractable plant compounds after their incorporation into soil was qualitatively and quantitatively studied in two forests under Juniperus communis L. and Pinus sylvestris L. Methods Leaf, litter and soil samples were taken from representative pine and juniper forests in central Spain. The lipid fraction was extracte...
Conference Paper
Four treatments of aerobic composting with different raw materials (BA: olive pomace, ES: manure, CA: almond husk) were evaluated during 176 days: pile A with 44%BA, 25%ES, 25%CA and turning; pile B with 44%BA, 11%ES, 44%CA and turning; C pile with 25%BA, 50% ES, 25%CA and turning; D pile with 44%BA, 11%ES, 44%CA and without turning over, in order...
Chapter
Full-text available
The so-called humic substances are widely distributed in soil, water and fossil organic resources and represent the greatest reservoir of organic carbon on the surface of the Earth. They include complex mixtures of altered biosynthetic materials in addition to newly-formed macromolecules. Apart from ecologically assessing the spatial variability of...
Article
Full-text available
The application of biochar as an organic amendment in polluted soils can facilitate their recovery by reducing the availability of contaminants. In the present work, the effect of biochar application to acid soils contaminated by heavy metal spillage is studied to assess its effect on the quantity and composition of soil organic matter (SOM), with...
Article
Biocrust cyanobacteria are ubiquitous organisms in dryland environments that can enhance soil stability and improve nutrient conditions in reconstructed or disturbed soils. Despite the demonstrated benefits of cyanobacterial inoculation for promoting soil fertility, there is limited knowledge about the impacts of introducing cultured cyanobacteria...
Article
Full-text available
Soil water repellency (SWR) is a physical property due to a complex interaction of factors (e.g., fire, soil organic matter, soil texture) that reduces the soil water infiltration capacity. Traditionally, SWR is attributed to the accumulation and redistribution of hydrophobic compounds within soil profile. To obtain further insight into chemical co...
Article
Full-text available
Aims of the study are to identify: 1) the main regularities of surface runoff formation due to downpours and, 2) the extent of erosion processes on arable chernozems under conditions of dissected relief and extreme continental climate. Location and time of the study. Field observations were carried out in Kuznetsk depression and Near-Ob areas durin...
Article
Full-text available
The sorption of three herbicides (alachlor, atrazine and linuron) on samples from six peats of pro-gressive degree of maturity (fibric, hemic or sapric types) and soil samples (dryland agricultural Calcic Luvisol amended with the peats) was determined. The extent of the sorption was examined in terms of peat maturity (up to 220 analytical descripto...
Article
Full-text available
Increasing food production while avoiding the progressive degradation of agricultural soils has become one of the major challenges at a global level. In consequence, the development of sustainable tillage methodologies or cultivation strategies is an important subject of current research. In fact, it has been observed that the implementation of red...
Article
In Castañar Cave (Cáceres, Spain), Mg-Si phases forming fibres and films occur associated with aragonite, magnesite, huntite and spheroidal dolomite in moonmilk, coatings and crust speleothems. A detailed study of bulk and carbonate-removed samples allowed us to identify the Mg-Si phases as kerolite (Mg3Si4O10(OH)2·nH2O) and sepiolite Mg4Si6O15(OH)...
Article
Full-text available
In a context of global change, soil has been identified as a potential carbon (C) sink, depending on land-use strategies. To detect the trends of carbon stocks after the implementation of new agricultural practices, early indicators, which can highlight changes in short timescales are required. This study proposes the combined use of stable isotope...
Article
Full-text available
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 enviro...
Article
This work studies carbon (C) and hydrogen (H) isotope composition of plant biomass and soil organic matter (SOM) in an attempt to assess both, changes exerted by fire and possible inputs of charred materials to the soil after a wildfire. Isotope composition of bulk soil, soil particle size fractions and biomass of the dominant standing vegetation i...
Preprint
Full-text available
Abstract. In a context of global change, soil has been identified as a potential carbon (C) sink, depending on land-use strategies. To detect the trends of carbon stocks after the implementation of new agricultural practices, early indicators, which can highlight changes in short timescales are required. This study proposes the combined use of sta...
Article
The impact of wildfires and of restoration actions on soil organic matter (SOM) content and structure was studied in a soil under pine (Pinus pinea) from Doñana National Park (SW Spain). Samples were collected from burnt areas before (B) and after post-fire restoration (BR) and compared with an unburnt (UB) site. Analytical pyrolysis (Py-GC/MS) was...
Article
Full-text available
Long-term stabilization of soil organic matter (SOM) plays an important role in the carbon cycle. Hence, understanding biogeochemical mechanisms of soil C sequestration is crucial to control its release to the atmosphere. This study aims at investigating the biogeochemical mechanisms of soil C sequestration. An exploratory assessment was carried ou...
Article
Full-text available
Thallium (Tl) is a hazardous trace metal that can harm human and environmental health. Tl pollution can result from the mining and smelting of Tl-bearing minerals, but also the natural weathering of Tl-bearing sulfide minerals may induce Tl release to the environment. In this study, hydrothermal deposits hosted in dolostone rocks sited along fossil...
Article
Full-text available
There is currently an active controversy about the variable influence of the factors involved in the total content and the quality of the soil organic matter (SOM), which translates into its resilience and stability against bio-degradation, and importantly on the rates of release of CO2 into the atmosphere. The aim of this work is to study the mole...
Conference Paper
Full-text available
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 r...
Article
Full-text available
A detailed and global quantitative assessment of the distribution of pyrogenic carbon (PyC) in soils remains unaccounted due to the current lack of unbiased methods for its routine quantification in environmental samples. Conventional oxidation with potassium dichromate has been reported as a useful approach for the determination of recalcitrant C...
Poster
Full-text available
AIMS: To characterise the SOM from a calcareous soil and to evaluate changes in its chemical structure linked to the use of pig slurry as fertiliser. M&M: From a long-term fertilisation experiment set in 2002, three treatments distributed in a randomized block design were chosen: a control, a mineral N fertilisation and a pig slurry treatment. Orga...
Article
Full-text available
The knowledge of biogeochemical mechanisms involved in soil organic carbon (SOC) storage is crucial to control its release to the atmosphere. In particular, the chemical composition of soil organic matter (SOM) plays an important role in the performance of the C storage and resilience in soils. The structural information provided by infrared spectr...
Conference Paper
Full-text available
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 app...
Article
Mulching has amply proven its effectiveness to mitigate post-fire soil erosion but its impacts on soil organic matter (SOM) quality and quantity continue poorly studied. The present study addressed this knowledge gap for a eucalypt plantation in central Portugal that had been burnt and, immediately after the wildfire, mulched with 13.6 Mg ha⁻¹ of e...
Article
Molecular assessment of the origin and transformation processes of soil organic matter (SOM) was carried out based on information obtained from ¹³C NMR and analytical pyrolysis of humic acids (HAs) in soils from wine-growing regions in Tenerife (Canary Islands, Spain). Principal component analysis, using as variables pyrolysis products, shows diffe...
Conference Paper
Full-text available
Long-term stabilization of soil organic matter (SOM) as recalcitrant forms plays an important role in the Earth’s carbon cycle. Hence, understanding biogeochemical mechanisms of soil C sequestration is crucial to control its emission to atmosphere. In this research the composition of humic acid (HA) is analyzed by Electrospray Ionization (ESI) Four...
Article
Full-text available
Environmental information provided by free lipids in soil samples collected from control and disturbed plots (Madrid, Spain), was assessed by comparing molecular assemblages of terpenoids and distribution patterns of alkanes and fatty acids (FAs), analyzed by gas chromatography-mass spectrometry (GC-MS). Wildfires in pine forests led to increased p...
Article
Fire is one of the most important modulating factors of the environment and the forest inducing chemical and biological changes on the most reactive soil component, the soil organic matter (SOM). Assuming the complex composition of the SOM, we used an ultra-high resolution mass spectrometry analysis technique to assess the chemical composition and...
Article
Full-text available
Biogeochemical factors responsible of the highly variable content of soil organic matter (SOM) in the different types of soils are poorly known. In particular, the role of organo-mineral interactions has frequently been considered, but less attention has been paid to the molecular composition of the SOM. The aim of this work was to contribute to a...
Conference Paper
Full-text available
There is currently an active controversy about the different influence of the factors that determine the quality of soil organic matter (SOM), which translates into its resilience and stability against biodegradation, with its effect derived in the rates of re-lease of CO2 into the atmosphere. In order to assess the impact of traditional soil-formi...
Conference Paper
Full-text available
The stable fraction of the soil organic matter (SOM), humic acids (HAs) was isolated from semiarid soils in central Spain. The HAs were analyzed by analytical pyrolysis combined with gas chromatography and mass spectrometry (Py-GC-MS) and studied for its correlations with hydrophysical properties of the corresponding soils viz., bulk density, poros...
Article
Full-text available
Purpose Data management strategies of pyrolysis results and NMR acquisition modes were examined in humic acids (HAs) from control soils and fire-affected soils. The information supplied by dipolar dephasing (DD) ¹³C NMR spectroscopy and Curie-point pyrolysis were used to assess chemical structures hardly recognizable and measurable, or of unclear i...
Preprint
Hydrothermal pyrite is an important source of thallium (Tl) but this rare element can be also detected in the secondary iron goethite-lepidocrocite and jarosite ores, associated to hydrothermal kerogen, manganese oxides, accessorial potassium minerals and tiny Tl-bearing clusters shielded in quartz masses. We studied Tl-bearing samples collected fr...
Chapter
Full-text available
The SOM is a heterogeneous material composed of diverse chemical structures with variable functionality. The study of the changes exerted by fire requires a combination of complementary analytical techniques. Thermogravimetric analysis and differential scanning calorimetry are useful to quantitatively differentiate thermolabile from recalcitrant o...
Article
Full-text available
Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) of humic acids (HAs) from 30 agricultural soils from a volcanic island (Tenerife, Spain) was used to discern the molecular characteristics of soil organic matter (SOM) associated to resilience. For faster perceptual identification of the results, the yields of the pyrolysis products in the f...
Conference Paper
Full-text available
The assessment of factors involved in soil carbon storage is crucial for developing the scientific bases of Earth's biogeochemical cycles. This is also the subject of current controversy about the extent to which the recalcitrance of soil organic matter depends on its molecular composition, or on external factors such as organo-mineral interactions...
Conference Paper
Full-text available
The soil lipid fraction consists of a complex mixture of low-polarity compounds of microbial or plant origin [1]. Homologues series of alkanes are present in all soil types: long-chain homologues are frequently considered to derive from epicuticular waxes of vascular plants, whereas short-chain homologues are thought to derive mainly from microorga...
Article
Full-text available
Pyrolysis-gas chromatography-mass spectrometry (Py-GC–MS) and thermally assisted hydrolysis and methylation (THM-GC–MS) were applied to 27 coal samples of lignite to high volatile bituminous rank (vitrinite reflectance %Ro =0.28–0.66) from the Malaysian states of Sabah and Sarawak on Borneo, to investigate rank effects on molecular properties. The...
Article
Full-text available
Purpose The present study focuses on a compositional characterization of the humic acid (HA) fraction of several wetland soils using solid-state ¹³C NMR spectroscopy. The data were analysed using the molecular mixing model (MMM), based on an empirical approach by Nelson and Baldock. The compositional data from HAs obtained with this model were used...
Article
Full-text available
The variable extent to which environmental factors are involved in soil carbon storage is currently a subject of controversy. In fact, justifying why some soils accumulate more organic matter than others is not trivial. Some abiotic factors such as organo-mineral associations have classically been invoked as the main drivers for soil C stabilizatio...
Conference Paper
Full-text available
The environmental factors involved in soil organic carbon sequestration remain unclear. The functional relationships between the macromolecular structure of the soil organic matter (SOM) and its resilience has been a constant in classical biogeochemical models. Other more recent hypotheses have postulated that preservation by soil minerals may play...
Chapter
Agriculture and forestry traditionally focus on improving plant growth traits based on an anthropocentric point of view. This paradigm has led to global problems associated to soil overexploitation such as soil losses, reductions of the C stock in soils, and the generalized use of fertilizers, which particularly increases the costs of production an...
Article
Full-text available
Forest fires cause immediate and lasting environmental impacts in soil organic matter (SOM) by modifying existing chemical structures, forming new ones, or adding/removing materials such as fresh or charred biomass. In this paper, the information provided by analytical pyrolysis (Py-GC/MS) of whole soil samples and two particle-size fractions (coar...
Article
Wildfire is a recurrent phenomenon in Mediterranean ecosystems and contributes to soil degradation and desertification, which are partially caused by alterations to soil organic matter (SOM). The SOM composition from a Cambisol under a Mediterranean forest affected by a wildfire is studied in detail in order to assess soil health status and better...
Article
Full-text available
The effects on the structural features of humic acids (HA) from dryland farming soils under long term management practices have been approached by analytical pyrolysis (Curie-point pyrolysis-gas chromatography/mass spectrometry, Py-GC/MS). The field experiments (started in 1987) include conventional, minimum and no-tillage plots, as well as non cul...
Article
The impact of continuous inputs of hydrocarbons from domestic waste oil recycling industries and further remediation practices, like inertization (liming and addition of ashes), have been studied in peri-urban soils in Spain in order to monitor the fate and spatial distribution patterns of potentially hazardous organic compounds. Physical and chemi...
Article
Pyrolysis-compound specific isotopic analysis (Py-CSIA: Py-GC-(FID)-C-IRMS) is a relatively novel technique that allows on-line quantitation of stable isotope proportions in chromatographically separated products released by pyrolysis. Validation of Py-CSIA technique is compulsory for molecular traceability in basic and applied research. In this wo...
Article
Polyethylene is probably the most used plastic material in daily life and its accurate analysis is of importance. In this communication the chemical structure of polyethylenes is studied in detail using conventional analytical pyrolysis (Py-GC/MS), bulk stable isotopic analysis (IRMS) and pyrolysis compound specific stable isotopic analysis (Py-CSI...
Article
Current environmental research is paying increasing attention to reliable analytical surrogates of soil quality. In this work a series of molecular features of soil organic matter were studied in different soil types from Central Spain with the purpose of identifying the soil functions most closely correlated with specific pools of soil organic mat...
Article
Full-text available
Wildfires represent an important disturbance in many ecosystems, especially in Mediterranean areas. It is well known that forest fires exert dramatic changes in soil organic matter (SOM) quality and quantity that in turn affect relevant and closely related characteristics like soil runoff and erosion response, through changes on factors like soil w...
Article
Large number of studies has demonstrated the usefulness of flash pyrolysis in association with GC-MS in releasing diagnostic volatile compounds informing about the complex composition of natural organic matter (NOM). This knowledge is of interest as regards monitoring agricultural and environmental processes including pollution. In this context the...
Article
Analytical pyrolysis (Py-GC/MS) at 500 °C was applied to study wood composition of Eucalyptus species (E. grandis, E. dunnii and E. benthamii) which are relevant for pulping in Uruguay. Multivariate data treatments mainly principal component analysis and discriminant analysis with automatic backwards variable selection were used to explore differen...
Conference Paper
Full-text available
In Mediterranean areas, the loss of soil physical quality is of particular concern due to the vulnerability of these ecosystems in relation to unfavourable climatic conditions, which usually lead to soil degradation processes and severe decline of its functionality. As a result, increasing scientific attention is being paid on the exploration of so...
Conference Paper
Full-text available
In countries at the Mediterranean basin, soil erosion by water¬—frequently associated with torrential precipitations¬—is an important land degradation problem. This is strongly related to the loss of soil functionality and, therefore, the knowledge of all factors influencing the soil response to precipitation is essential to select the most suitabl...
Conference Paper
Full-text available
The chemical structure of a low-density green polyethylene was studied in detail using conventional analytical pyrolysis (Py-GC/MS), bulk C, N, H, O isotopic ratio (TC/EA-IRMS) and compound specific isotope analysis (CSIA) of stable light elements C, N, and H (Py-GC- (FID)-C/TC-IRMS). Py-GC/MS: a series of n-alkane, α- alkene and α,ω-diene (C8 t...
Article
Full-text available
Aromaticity of soil organic matter has often been considered an independent index of biogeochemical maturity, recalcitrance, and persistence of C in soils. The structural characteristics of soil humic acids (HAs) from various origins are studied by bi- and multivariate statistical exploratory analyses to select chemical descriptors surrogated to ar...
Article
A valuable feature of sewage sludge used for restoring degraded soils is its supplying capacity for C, N and P. A series of laboratory incubation experiments to quantify the release of N and P from raw (dried) and co-composted urban sewage sludges applied to mine dump soil were conducted. The effect of application dose (0–100 g kg−1) and incubation...
Chapter
It is well known that humic acids (HAs) have a complex heterogeneous composition which depends not only on the precursor organic constituents but to large extent on the environmental factors in the soil system. In this study, an ‘omic’ approach was carried out taking advantage of the information from different data matrices obtained by analytical p...
Chapter
An attempt to automated the interpretation of mid-infrared (MIR) spectral profiles of humic acids (HAs) from volcanic ash soils was carried out with the aid of plots displaying the valuable importance for projection (VIP) scores computed by partial least squares (PLS) regression. A set of about 200 dependent variables from whole soils and HAs was e...
Article
The objective of this study is to analyze soil hydrophysical properties in addition to the molecular composition of the organic matter in semiarid Mediterranean cereal agroecosystems. Aggregate water-stability, total porosity, water holding capacity, and b and c parameters of the Kostiakov's equation for soil infiltration were determined using a do...
Conference Paper
Full-text available
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...
Article
There is little information available about the molecular composition of organic fractions with a possible bearing in soil water repellency. Extremely water-repellent forest soils developed on granites or schists, under vegetation of pine or eucalyptus, were used for sequential isolation of two lipid fractions: free lipid extracted with petroleum e...