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1.
Ecol Evol ; 13(8): e10392, 2023 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-37600493

RESUMEN

Mammal diversity affects carbon concentration in Amazonian soils. It is known that some species traits determine carbon accumulation in organisms (e.g., size and longevity), and are also related to feeding strategies, thus linking species traits to the type of organic remains that are incorporated into the soil. Trait diversity in mammal assemblages - that is, its functional diversity - may therefore constitute another mechanism linking biodiversity to soil organic matter (SOM) accumulation. To address this hypothesis, we analyzed across 83 mammal assemblages in the Amazon biome (Guyana), the elemental (by ED-XRF and CNH analysis) and molecular (FTIR-ATR) composition of SOM of topsoils (401 samples) and trait diversity (functional richness, evenness, and divergence) for each mammal assemblage. Lower mammal functional richness but higher functional divergence were related to higher content of carbonyl and aliphatic SOM, potentially affecting SOM recalcitrance. Our results might allow the design of biodiversity management plans that consider the effect of mammal traits on carbon sequestration and accumulation in soils.

2.
Trends Ecol Evol ; 38(7): 602-604, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37045717

RESUMEN

Trait evolution is shaped by carbon economics at the organismal level. Here, we expand this idea to the ecosystem level and show how the trait diversity of ecological communities influences the carbon cycle. Systematic shifts in trait diversity will likely trigger changes in the carbon cycle.


Asunto(s)
Biodiversidad , Ecosistema , Fenotipo , Ciclo del Carbono , Carbono
3.
iScience ; 26(3): 106088, 2023 Mar 17.
Artículo en Inglés | MEDLINE | ID: mdl-36915677

RESUMEN

Diversity of plants and animals influence soil carbon through their contributions to soil organic matter (SOM). However, we do not know whether mammal and tree communities affect SOM composition in the same manner. This question is relevant because not all forms of carbon are equally resistant to mineralization by microbes and thus, relevant to carbon storage. We analyzed the elemental and molecular composition of 401 soil samples, with relation to the species richness of 83 mammal and tree communities at a landscape scale across 4.8 million hectares in the northern Amazon. We found opposite effects of mammal and tree richness over SOM composition. Mammal diversity is related to SOM rich in nitrogen, sulfur and iron whereas tree diversity is related to SOM rich in aliphatic and carbonyl compounds. These results help us to better understand the role of biodiversity in the carbon cycle and its implications for climate change mitigation.

4.
Spectrochim Acta A Mol Biomol Spectrosc ; 285: 121893, 2023 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-36137500

RESUMEN

The transformation of sapwood (SW) into heartwood (HW) during ageing of wood tissues is the result of physiological and biochemical changes initiated in the transition zone (TZ). These changes contribute to the evolution of active (living) wood cells in SW into less/non-active (dead) wood cells in HW. Previous studies established that the biosynthesis of extractive contents is the most prominent process that occurs in the TZ. To improve our understanding of the extent and characteristics of the TZ in oak wood, the present study reports the results of color parameters (using CIELab color space) and molecular structure and composition of polysaccharide and lignin compounds (using FTIR-ATR and Py-GC-MS). For that purpose, six wood cores from individual living oak (Quercus spp.) trees were collected from two forests with similar environmental conditions, located in the Basque Country (Northern Spain). The color data indicated significant differences between SW, TZ and HW by showing that SW samples were characterized by higher hue (h°) and lower redness (a*) values than the HW, and intermediate values for the TZ. They also suggested that the variations of wood color from SW to HW occur gradually, along a wide TZ counting 4-10 measurement points in a row, depending on the tree. Furthermore, FTIR and Py-GC-MS data gave evidence of the variation trends of polysaccharide and lignin contents in the radial direction, through various FTIR ratios (1735/1325, 1590/1735, 1590/1230, and 1230/1325 cm-1) and one pyrolysis ratio (acetic acid/total polysaccharide: Ps01/Tot_Ps). The observed variations in this present study suggest that the cross-sectional transition patterns can be related to the continuous lignification process of xylem parenchyma cells, as well as the storage of polysaccharide compounds. These results contribute to our fundamental knowledge on the TZ, which may be valuable in research and industrial applications where a clear delimitation of sapwood and/or heartwood is required.


Asunto(s)
Quercus , Madera , Madera/química , Árboles/química , Árboles/fisiología , Lignina/análisis , Estudios Transversales
5.
PLoS One ; 17(9): e0274849, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-36166442

RESUMEN

The study of animal and plant fibers related to grave furnishing, garments, and grave goods in thousands-of-year-old burials provides new insights into these funerary practices. Their preservation presupposes favorable conditions, where bacterial and fungal activity is at a minimum, as in anaerobic, wet, salty, arid, or frozen environments. The extreme acidic-soil environments (i.e., podzols) of Finland pose a challenge when it comes to studying funerary deposits, as human remains are rarely found. However, its potential to preserve microparticles allows us to approach the funerary event from a totally different point of view. Here, we present the first multiproxy analyses of a Mesolithic deposit from Finland. A red-ochre burial of a child found in Majoonsuo is studied by analyzing 1) microscopic fibers, 2) fatty acids, and 3) physical-chemical (CIELab color, pH, grain size) properties of 60 soil samples and associated materials. The microscopic fibers evidenced the remains of waterfowl downy feathers, a falcon feather fragment, canid and small rodent hairs as well as bast fibers. These could have been used in furnishing the grave and as ornaments or clothes. Canid hairs could belong to a dog inhumation, or more likely to canid fur used as grave good/clothes. Samples with microparticles have more long-chain and unsaturated fatty acids, although animal species identification was not possible. Soil properties indicate that the burial was made in the local soil, adding homogeneous red ochre and removing the coarser material; no bioturbation was found. The highly acidic sandy soil, together with a slight increase in finer particles when ochre is abundant, probably resulted in micro-scale, anoxic conditions that prevented bacterial attack. This study reveals the first animal hairs and feathers from a Finnish Mesolithic funerary context, and provides clues about how their preservation was possible.


Asunto(s)
Entierro , Plumas , Animales , Entierro/métodos , Niño , Perros , Ácidos Grasos , Finlandia , Humanos , Suelo
6.
Sci Total Environ ; 851(Pt 1): 158015, 2022 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-35970463

RESUMEN

Archaeological burial environments are useful archives to investigate the long-term trends and the behaviour of mercury. In order to understand the relationship between mercury, skeletons and soil, we applied Partial Least Squares - Structural Equation Modelling (PLS-SEM) to a detailed, multisampling (n = 73 bone samples +37 soil samples) design of two archaeological graves dating to the 6th to 7th centuries CE (A Lanzada site, NW Spain). Mercury content was assessed using a DMA-80, and data about bone structure and the grave soil/sediments were obtained using FTIR-ATR spectroscopy. The theoretical model is supported by proxies of bone structure, grave soil/sediments, and location of the bone within the skeleton. The general model explained 61 % of mercury variance. Additionally, Partial Least Square - Prediction Oriented Segmentation (PLS-POS) was also used to check for segmentation in the dataset. POS revealed two group of samples depending on the bone phase (hydroxyapatite or collagen) controlling the Hg content, and the corresponding models explained 86 % and 76 % of Hg variance, respectively. The results suggest that mercury behaviour in the graves is complex, and that mercury concentrations were influenced by i) the ante-mortem status of the bone matrix, related to the weight of each bone phase; ii) post-mortem evolution of bone crystallinity, where bone loses mercury with increasing alteration; and iii) the proximity of the skeletal pieces to mercury target organs, as decomposition and collapse of the thoracic and abdominal soft tissues causes a secondary mercury enrichment in bones from the body trunk during early post-mortem. Skeletons provide a source of mercury to the soil whereas soil/sediments contribute little to skeletal mercury content.


Asunto(s)
Mercurio , Contaminantes del Suelo , Restos Mortales/química , Colágeno , Humanos , Hidroxiapatitas , Análisis de Clases Latentes , Mercurio/análisis , Suelo/química , Contaminantes del Suelo/análisis
7.
Sci Rep ; 12(1): 10619, 2022 06 23.
Artículo en Inglés | MEDLINE | ID: mdl-35739214

RESUMEN

In Archaeology much emphasis is dedicated to bone preservation, but less attention is paid to the burial soil (i.e., Necrosol), despite its crucial role in governing the geochemical environment. The interaction between human remains and sediments starts after inhumation, leading to bidirectional physico-chemical changes. To approach these complex, bidirectional processes, we sampled at high resolution (n = 46) two post-Roman wooden coffin burials (one single and another double), and the coeval paleosol (n = 20; nearby pedo-sedimentary sequence). The samples were analysed for physical (grain size, colour) and chemical (pH; LOI; elemental composition: FTIR-ATR, XRF, C, N) properties. Principal component analysis enabled to identify five main pedogenetical processes: decalcification, melanization, acidification, neoformation of secondary minerals (i.e., clays) and enrichment in phosphorus. Melanization, acidification and phosphorous enrichment seem to be convergent processes in Necrosols-irrespective of the parent material. Decalcification may be restricted to carbonate containing soil/sediments. Despite not mentioned in previous research, clay formation might also be an overall process. Compared to the local, coeval paleosol, pedogenesis in the studied burial soils was low (double burial) to moderate (single burial). Our results also emphasize the need to study the finer soil fractions, as they provide clues both on soil formation and bone diagenesis.


Asunto(s)
Entierro , Arena , Arqueología , Arcilla , Humanos , Minerales/química , Fósforo , Suelo
8.
Sci Rep ; 11(1): 21231, 2021 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-34707177

RESUMEN

Mercury environmental cycle and toxicology have been widely researched. Given the long history of mercury pollution, researching mercury trends in the past can help to understand its behaviour in the present. Archaeological skeletons have been found to be useful sources of information regarding mercury loads in the past. In our study we applied a soil multi-sampling approach in two burials dated to the 5th to 6th centuries AD. PLRS modelling was used to elucidate the factors controlling mercury distribution. The model explains 72% of mercury variance and suggests that mercury accumulation in the burial soils is the result of complex interactions. The decomposition of the bodies not only was the primary source of mercury to the soil but also responsible for the pedogenetic transformation of the sediments and the formation of soil components with the ability to retain mercury. The amount of soft tissues and bone mass also resulted in differences between burials, indicating that the skeletons were a primary/secondary source of mercury to the soil (i.e. temporary sink). Within burial variability seems to depend on the proximity of the soil to the thoracic area, where the main mercury target organs were located. We also conclude that, in coarse textured soils, as the ones studied in this investigation, the finer fraction (i.e. silt + clay) should be analysed, as it is the most reactive and the one with the higher potential to provide information on metal cycling and incipient soil processes. Finally, our study stresses the need to characterise the burial soil environment in order to fully understand the role of the interactions between soil and skeleton in mercury cycling in burial contexts.

9.
PLoS One ; 16(3): e0246821, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-33730018

RESUMEN

Southern Africa sits at the junction of tropical and temperate systems, leading to the formation of seasonal precipitation zones. Understanding late Quaternary paleoclimatic change in this vulnerable region is hampered by a lack of available, reliably-dated records. Here we present a sequence from a well-stratified sedimentary infill occupying a lower slope basin which covers 17,060 to 13,400 cal yr BP with the aim to reconstruct paleoclimatic variability in the high Drakensberg during the Late Glacial. We use a combination of pollen, total organic carbon and nitrogen, δ13C, Fourier transform infrared spectroscopy attenuated total reflectance (FTIR-ATR) spectral and elemental data on contiguous samples with high temporal resolution (10 to 80 years per sample). Our data support a relatively humid environment with considerable cold season precipitation during what might have been the final stage of niche-glaciation on the adjoining southern aspects around 17,000 cal yr BP. Then, after an initial warmer and drier period starting ~15,600 cal yr BP, we identify a return to colder and drier conditions with more winter precipitation starting ~14,380 cal yr BP, which represents the first local evidence for the Antarctic Cold Reversal (ACR) in this region. On decadal to centennial timescales, the Late Glacial period was one marked by considerable climatic fluctuation and bi-directional environmental change, which has not been identified in previous studies for this region. Our study shows complex changes in both moisture and thermal conditions providing a more nuanced picture of the Late Glacial for the high Drakensburg.


Asunto(s)
Evolución Biológica , Fósiles , Sedimentos Geológicos , África Austral , Estaciones del Año , Árboles
10.
Sci Total Environ ; 768: 144352, 2021 May 10.
Artículo en Inglés | MEDLINE | ID: mdl-33454472

RESUMEN

Seagrasses are distributed all along the coast of the Mediterranean Sea being Posidonia oceanica and Cymodocea nodosa the most common species. They promote sedimentation, leading to the formation of well-structured soils. Over the last decade, a growing attention has been paid to their role as CO2 sinks in the form of organic carbon (Corg) and to their use as environmental archives. However, most of the knowledge about pedogenetic processes in these soils refer to the rhizosphere. This study aims to understand seagrass soils biogeochemistry in the rhizosphere and below, which in turn can help to understand their long term formation processes. Fifteen cores were strategically sampled along a 350 km stretch of the Southeast Iberian coast, and analyzed for elemental composition (XRF core-scanning), magnetic susceptibility, Corg content and gran size distribution. The cores were dated by 210Pb and 14C-AMS techniques to estimate soil accretion. Principal component analysis was used to explore the main geochemical processes linked to soil formation. The results showed that terrestrial runoff plays a key role in meadow soil composition. Furthermore, Corg accumulation did not follow any general depth trend in our soil records, suggesting that temporal variation in Corg inputs is an important factor in determining carbon depth distribution within the soil. We obtained evidence that the establishment of well-developed, stable C. nodosa meadows in the Mediterranean Sea may be promoted by adverse environmental conditions to P. oceanica settlement. Metal's behavior within the meadow deposit and their interaction with organic matter and carbonates is unclear. The results presented in this paper highlight the importance of the influence of land-based inputs in the characteristics of seagrass meadow deposits, highly determining their Corg content, as well as the need for further studies on metal behavior, to understand their full potential as environmental records.


Asunto(s)
Alismatales , Suelo , Carbono , Sedimentos Geológicos , Mar Mediterráneo
11.
Sci Total Environ ; 754: 142117, 2021 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-33254936

RESUMEN

Seagrasses are marine angiosperms that can form highly productive, and valuable underwater meadows, which are currently in regression. A reliable assessment of their status and future evolution requires studies encompassing long-term temporal scales. With the aim of understanding seagrass ecosystem dynamics over the last centuries and millennia, twelve sediment cores were studied from seagrass meadows located along the Andalusian coast and at the Cabrera Island (western Mediterranean). This study is pioneer in using Fourier Transform Infrared (FTIR) spectroscopy as a tool to study environmental change in seagrass sediments. FTIR is a form of vibrational spectroscopy that provides information about the sediment chemical composition. Principal Component Analysis (PCA) was used to summarise spatio-temporal data of the FTIR vibratory peaks in combination with climate and geochemical proxy data. Several PCA signals were identified: (1) one likely related to the relative changes of the main primary producers and the sedimentary environment (carbonate or siliciclastic sediments, with aromatic or aliphatic organic matter); (2) the marine community production (polysaccharides, total organic matter content and biogenic silica); and (3) the seagrass production (aromatics, carbohydrates, phenols, proteins and lipids). A decrease of seagrass production along the mainland coast was evident since AD ~1850, which may be due to combined negative impacts of seawater warming, local anthropogenic impacts, and extreme setting conditions. The legacy of these combined stressors might have influenced the current poor state of seagrass meadows in the Alboran Sea. Our results also revealed a significant long-term trade-off between the level of seagrass production and its temporal stability (calculated as the inverse of the coefficient of variation). This study provides a reliable baseline data, helping to assess the magnitude of seagrass regression and its drivers. This paleoecological information can help design more targeted management plans and identify meadows where local management could be more efficient.


Asunto(s)
Alismatales , Ecosistema , Algoritmos , Clima , Lípidos , Análisis de Componente Principal
12.
Sci Total Environ ; 757: 143940, 2021 Feb 25.
Artículo en Inglés | MEDLINE | ID: mdl-33321335

RESUMEN

The application of statistical modeling is still infrequent in mercury research in peat, despite the ongoing debate on the weight of the diverse factors (climate, peat decomposition, vegetation changes, etc.) that may affect mercury accumulation. One of the few exceptions is the Hg record of Pinheiro mire (souheast Brazil). Previous studies on this mire modeled mercury using principal components regression and partial least squares. These methods assume independence between factors, which is seldom the case in natural systems, thus hampering the identification of mediating effects and interactions. To overcome these limitations, in this reserach we use structural equation modeling (PLS-SEM) to model mercury and bromine peat records - bromine has been used in some investigations to normalize mercury accumuation. The mercury model explained 83% of the variance and suggested a complex control: increased peat decomposition, dust deposition and humid climates enhanced mercury accumulation, while increased mineral fluxes resulted in a decrease in mercury accumulation. The bromine model explained 90% of the variation in concentrations: increased dust deposition and peat decomposition promoted bromine accumulation, while time (i.e. peat age) promoted bromine depletion. Thus, although mercury and bromine are both organically bound elements with relevant atmospheric cycles the weights of the factors involved in their accumulation differed significantly. Our results suggest caution when using bromine to normalize mercury accumulation. PLS-SEM results indicate a large time dependence of peat decomposition, catchment mineral fluxes, long-term climate change, and atmospheric deposition; while atmospheric dust, mineral fluxes and peat decomposition showed high to moderate climate dependency. In particular, they also point to a relevant role of autogenic processes (i.e. the build up and expansion of the mire within the catchment), which controlled local mineral fluxes; an aspect that has seldom been considered.

13.
Sci Rep ; 10(1): 17888, 2020 10 21.
Artículo en Inglés | MEDLINE | ID: mdl-33087827

RESUMEN

Collagen is the main structural and most abundant protein in the human body, and it is routinely extracted and analysed in scientific archaeology. Its degree of preservation is, therefore, crucial and several approaches are used to determine it. Spectroscopic techniques provide a cost-effective, non-destructive method to investigate the molecular structure, especially when combined with multivariate statistics (chemometric approach). In this study, we used FTIR-ATR spectroscopy to characterise collagen extracted from skeletons recovered from necropoleis in NW Spain spanning from the Bronze Age to eighteenth century AD. Principal components analysis was performed on a selection of bands and structural equation models (SEM) were developed to relate the collagen quality indicators to collagen structural change. Four principal components represented: (i) Cp1, transformations of the backbone protein with a residual increase in proteoglycans; (ii) Cp2, protein transformations not accompanied by changes in proteoglycans abundance; (iii) Cp3, variations in aliphatic side chains and (iv) Cp4, absorption of the OH of carbohydrates and amide. Highly explanatory SEM models were obtained for the traditional collagen quality indicators (collagen yield, C, N, C:N), but no relationship was found between quality and δ13C and δ15N ratios. The observed decrease in C and N content and increase in C:N ratios is controlled by the degradation of protein backbone components and the relative preservation of carbon-rich compounds, proteoglycans and, to a lesser extent, aliphatic moieties. Our results suggest that FTIR-ATR is an ideal technique for collagen characterization/pre-screening for palaeodiet, mobility and radiocarbon research.


Asunto(s)
Huesos/metabolismo , Colágeno/metabolismo , Arqueología , Humanos , Análisis de Componente Principal , Conformación Proteica , Espectroscopía Infrarroja por Transformada de Fourier
14.
Sci Total Environ ; 737: 139619, 2020 Oct 01.
Artículo en Inglés | MEDLINE | ID: mdl-32783819

RESUMEN

The focus of this paper is to briefly discuss the major advances in scientific thinking regarding: a) processes governing the fate and transport of mercury in the environment; b) advances in measurement methods; and c) how these advances in knowledge fit in within the context of the Minamata Convention on Mercury. Details regarding the information summarized here can be found in the papers associated with this Virtual Special Issue of STOTEN.

15.
Sci Total Environ ; 742: 140554, 2020 Nov 10.
Artículo en Inglés | MEDLINE | ID: mdl-32721726

RESUMEN

Blue carbon ecosystems (BCE) play an essential role in the global carbon cycle by removing atmospheric carbon dioxide and storing it as organic carbon (OC) in biomass and sediments. However, organic matter (OM) deposition and degradation/preservation processes are poorly understood, especially on the long-term and at molecular scales. We analysed sediment samples from six cores collected in tidal marshes, mangroves and seagrasses (up to 150 cm long cores spanning up to 10,000 yrs of OC accumulation) from Spencer Gulf (South Australia), by pyrolysis (Py-GC-MS and THM-GC-MS), and we compared the results with elemental and stable isotope data, to decipher OM provenance and to assess degradation/preservation dynamics. The results showed that: (1) the major biopolymers preserved were polysaccharides, polyphenolic moieties (lignin and tannin) and polymethylenic moieties (e.g. cutin, suberin, chlorophyll) with smaller apportions of proteins and resins; (2) the OM originates predominantly from vascular plant materials (in particular lignocellulose) that have been well-preserved, even in some of the oldest sediments; (3) mangroves were found to be the most efficient OC sinks, partially explained by syringyl lignin preservation; (4) seagrasses were shown to store polysaccharide-enriched OM; (5) large proportions of polycyclic aromatic hydrocarbons (PAHs) in surficial tidal marsh and mangrove sediments probably reflect pyrogenic OM from industrial combustion, and; (6) "ecosystem shifts", i.e. mangrove encroachment in tidal marsh and transition from seagrass to mangrove, were detected. Deposition environment and source vegetation control OC sequestration and there is no specific recalcitrant form of OM that is selectively preserved. For the first time, we demonstrate how analytical pyrolysis in combination with stable isotope analysis can be used to reconstruct (palaeo-)ecological shifts between different BCE. This study improves our knowledge on OC accumulation dynamics and the response of BCE to environmental change, which can inform the implementation of strategies for climate change mitigation.

16.
Environ Pollut ; 260: 114040, 2020 May.
Artículo en Inglés | MEDLINE | ID: mdl-32004966

RESUMEN

A high-resolution soil sampling has been applied to two forest podzols (ACB-I and ACB-II) from SW Europe in order to investigate the soil components and processes influencing the content, accumulation and vertical distribution of Hg. Total Hg contents (THg) were 28.0 and 23.6 µg kg-1 in A horizons of ACB-I and ACB-II, then they strongly decreased in the E horizons and peaked in the Bhs horizons of both soils (55.3 and 63.0 µg kg-1). THg decreased again in BwC horizons to 17.0 and 39.8 µg kg-1. The Bhs horizons accounted for 46 and 38% of the total Hg stored (ACB-I and ACB-II, respectively). Principal component analysis (PCA) and principal components regression (PCR), i.e. using the extracted components as predictors, allowed to distinguish the soil components that accounted for Hg accumulation in each horizon. The obtained model accurately predicted accumulated Hg (R2 = 0.845) through four principal components (PCs). In A horizons, Hg distribution was controlled by fresh soil organic matter (PC4), whereas in E horizons the negative values of all PCs were consistent with the absence of components able to retain Hg and the corresponding very low THg concentrations. Maximum THg contents in Bhs horizons coincided with the highest peaks of reactive Fe and Al compounds (PC1 and PC2) and secondary crystalline minerals (PC3) in both soils. The THg distribution in the deepest horizons (Bw and BwC) seemed to be influenced by other pedogenetic processes than those operating in the upper part of the profile (A, E and Bhs horizons). Our findings confirm the importance of soils in the global Hg cycling, as they exhibit significant Hg pools in horizons below the uppermost O and A horizons, preventing its mobilization to other environmental compartments.


Asunto(s)
Monitoreo del Ambiente , Mercurio , Contaminantes del Suelo , Suelo , Europa (Continente) , Bosques
17.
Sci Total Environ ; 710: 136319, 2020 Mar 25.
Artículo en Inglés | MEDLINE | ID: mdl-31926414

RESUMEN

Atmospheric metal pollution is a major health concern whose roots pre-date industrialization. This study pertains the analyses of ancient human skeletons and compares them with natural archives to trace historical environmental exposure at the edge of the Roman Empire in NW Iberia. The novelty of our approach relies on the combination of mercury, lead and lead isotopes. We found over a 700-year period that rural Romans incorporated two times more mercury and lead into their bones than post-Romans inhabiting the same site, independent of sex or age. Atmospheric pollution sources contributed on average 57% (peaking at 85%) of the total lead incorporated into the bones in Roman times, which decreased to 24% after the decline of Rome. These values and accompanying changes in lead isotopic composition mirror changes in atmospheric Pb deposition recorded in local peatlands. Thus, skeletons are a time-transgressive archive reflecting contaminant exposure.


Asunto(s)
Huesos/química , Exposición a Riesgos Ambientales , Monitoreo del Ambiente , Contaminación Ambiental , Humanos , Plomo , Mercurio , Mundo Romano
18.
Sci Total Environ ; 709: 134800, 2020 Mar 20.
Artículo en Inglés | MEDLINE | ID: mdl-31887515

RESUMEN

Environmental archives offer an opportunity to reconstruct temporal trends in atmospheric Hg deposition at various timescales. Lake sediment and peat have been the most widely used archives; however, new records from ice, tree rings, and the measurement of Hg stable isotopes, are offering new insights into past Hg cycling. Preindustrial Hg deposition has been studied over decadal to millennial timescales extending as far back as the late Pleistocene. Exploitation of mercury deposits (mainly cinnabar) first began during the mid to late Holocene in South America, Europe, and Asia, but increased dramatically during the Colonial era (1532-1900) for silver production. However, evidence for preindustrial Hg pollution is restricted to regions directly downwind or downstream of cinnabar or precious metal mining centers. Excluding these areas, there has been an approximately four-fold increase in atmospheric deposition globally over the industrial era (i.e., since 1800-1850), though regional differences exist, especially during the early 20th Century. Lake sediments, peat, ice, and tree rings are all influenced by (and integrate) a range of processes. For example, lake sediments are influenced by atmospheric deposition, sediment focusing, and the input of allochthonous material from the watershed, peat records reflect atmospheric deposition and biotic uptake, ice cores are a record of Hg scrubbed during precipitation, and tree rings record atmospheric concentrations. No archive represents an absolute record of past Hg deposition or concentrations, and post-depositional transformation of Hg profiles remains an important topic of research. However, natural archives continue to provide important insight into atmospheric Hg cycling over various timescales.

19.
Data Brief ; 21: 1861-1863, 2018 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-30519608

RESUMEN

Data in this article are related to the chemical characterization of various oak wood samples. Data have been obtained by the application of Fourier Transform Infrared (FTIR) spectroscopy and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) to living tree species and shipwreck wood fragments. Measurements were performed on individual rings in order to facilitate the understanding of the variability in wood chemical composition along the radial cores, i.e. the same kind of material traditionally used for dendrochronological analysis. The data in this article is labelled according to the anatomical sections of the wood (sapwood, transition wood and heartwood) where the samples were taken. The experimental background and the results can be found in the related research article, "Chemometric tools for identification of wood from different oak species and their potential for provenancing of Iberian shipwrecks (16th-18th centuries CE)" (Traoré et al., 2018).

20.
Wood Sci Technol ; 52(2): 487-504, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29497215

RESUMEN

Attenuated total reflectance-Fourier transform infrared (FTIR-ATR) spectroscopy was applied to 120 samples of heartwood rings from eight individual pine trees from different locations in Spain. Pinus sylvestris cores were collected at the Artikutza natural park (Ps-ART). Pinus nigra cores were collected in Sierra de Cazorla (Pn-LIN) and in La Sagra Mountain (Pn-LSA). Three discriminant analysis tests were performed using all bands (DFT), lignin bands only (DFL) and polysaccharides bands only (DFP), to explore the ability of FTIR-ATR to separate between species and growing location. The DFL model enabled a good separation between pine species, whereas the DFP model enabled differentiation for both species and growing location. The DFT model enabled virtually perfect separation, based on two functions involving twelve FTIR bands. Discrimination between species was related to bands at 860 and 1655 cm-1, which were more intense in P. sylvestris samples, and bands at 1425 and 1635 cm-1, more intense in P. nigra samples. These vibrations were related to differences in lignin structure and polysaccharide linear chains. Discrimination between growing locations was mainly related to polysaccharide absorptions: at 900, 1085 and 1335 cm-1 more representative of Pn-LIN samples, and at 1105 and 1315 cm-1 mostly associated to Pn-LSA samples. These absorptions are related to ß-glycosidic linkages (900 cm-1), cellulose and hemicellulose (C-O bonds, 1085 and 1105 cm-1) and content in amorphous/crystalline cellulose (1315 and 1335 cm-1). These results show that FTIR-ATR in combination with multivariate statistics can be a useful tool for species identification and provenancing for pine wood samples of unknown origin.

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