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1.
Environ Pollut ; 292(Pt B): 118478, 2022 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-34752789

RESUMO

Laboratory experiments and point observations, for instance in wetlands, have shown evidence that microbial sulfate reduction (MSR) can lower sulfate and toxic metal concentrations in acid mine drainage (AMD). We here hypothesize that MSR can impact the fate of AMD in entire catchments. To test this, we developed a sulfur isotope fractionation and mass-balance method, and applied it at multiple locations in the catchment of an abandoned copper mine (Nautanen, northern Sweden). Results showed that MSR caused considerable, catchment-scale immobilization of sulfur corresponding to a retention of 27 ± 15% under unfrozen conditions in the summer season, with local values ranging between 13 ± 10% and 53 ± 18%. Present evidence of extensive MSR in Nautanen, together with previous evidence of local MSR occurring under many different conditions, suggest that field-scale MSR is most likely important also at other AMD sites, where retention of AMD may be enhanced through nature-based solutions. More generally, the developed isotope fractionation analysis scheme provides a relatively simple tool for quantification of spatio-temporal trends in MSR, answering to the emerging need of pollution control from cumulative anthropogenic pressures in the landscape, where strategies taking advantage of MSR can provide viable options.


Assuntos
Mineração , Sulfatos , Ácidos , Enxofre , Isótopos de Enxofre/análise
2.
PLoS One ; 16(10): e0257444, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34710099

RESUMO

Floodplains represent critical nursery habitats for a variety of fish species due to their highly productive food webs, yet few tools exist to quantify the extent to which these habitats contribute to ecosystem-level production. Here we conducted a large-scale field experiment to characterize differences in food web composition and stable isotopes (δ¹³C, δ¹5N, δ³4S) for salmon rearing on a large floodplain and adjacent river in the Central Valley, California, USA. The study covered variable hydrologic conditions including flooding (1999, 2017), average (2016), and drought (2012-2015). In addition, we determined incorporation rates and tissue fractionation between prey and muscle from fish held in enclosed locations (experimental fields, cages) at weekly intervals. Finally, we measured δ³4S in otoliths to test if these archival biominerals could be used to reconstruct floodplain use. Floodplain-reared salmon had a different diet composition and lower δ13C and δ³4S (δ¹³C = -33.02±2.66‰, δ³4S = -3.47±2.28‰; mean±1SD) compared to fish in the adjacent river (δ¹³C = -28.37±1.84‰, δ³4S = +2.23±2.25‰). These isotopic differences between habitats persisted across years of extreme droughts and floods. Despite the different diet composition, δ¹5N values from prey items on the floodplain (δ¹5N = 7.19±1.22‰) and river (δ¹5N = 7.25±1.46‰) were similar, suggesting similar trophic levels. The food web differences in δ13C and δ³4S between habitats were also reflected in salmon muscle tissue, reaching equilibrium between 24-30 days (2014, δ¹³C = -30.74±0.73‰, δ³4S = -4.6±0.68‰; 2016, δ¹³C = -34.74 ±0.49‰, δ³4S = -5.18±0.46‰). δ³4S measured in sequential growth bands in otoliths recorded a weekly time-series of shifting diet inputs, with the outermost layers recording time spent on the floodplain (δ³4S = -5.60±0.16‰) and river (δ³4S = 3.73±0.98‰). Our results suggest that δ¹³C and δ³4S can be used to differentiate floodplain and river rearing habitats used by native fishes, such as Chinook Salmon, across different hydrologic conditions and tissues. Together these stable isotope analyses provide a toolset to quantify the role of floodplains as fish habitats.


Assuntos
Salmão/crescimento & desenvolvimento , Fenômenos Fisiológicos da Nutrição Animal , Animais , Isótopos de Carbono/análise , Ecossistema , Cadeia Alimentar , Isótopos de Nitrogênio/análise , Rios , Salmão/fisiologia , Isótopos de Enxofre/análise
3.
Talanta ; 235: 122708, 2021 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-34517581

RESUMO

Conventional sulfur isotope measurements in complex natural liquid or solid samples via GS-IRMS are complicated, time consuming and relatively expensive. Here we assessed a novel 'collision cell' based ICP-MS/MS approach which can determine the sulfur isotope abundances (i.e., 34S/32S ratios, expressed as δ34S) in complex coastal waters rapidly, accurately and with minimal sample preparation. The approach was validated via repeated ICP-MS/MS measurement of S isotope certified reference materials (CRM) providing accurate and reproducible results, with a typical uncertainty on δ34S of around 1.1-1.5‰ (1SD). This novel approach is suitable for water samples with sulfur concentrations at or above 2 µg/mL (ppm). Matrix matching between samples and the CRM was necessary when seawater-like solutions were analysed addressing common matrix related errors. The ICP-MS/MS approach was used to investigate δ34S signature of porewaters from a variety of coastal systems in South Australia (including acid sulfate soils), and how they responded to progressive seawater inundation. Importantly, inundation induced a shift in S isotope ratio in affected porewaters in which δ34S approached that of seawater. The simple sample preparation, with rapid and accurate δ34S determination of complex natural waters using the ICP MS/MS approach, greatly increases the applicability of sulfur isotope tracing studies to identify and monitor sources and bio-geochemical pathways of S in coastal and near-surface environments.


Assuntos
Água do Mar , Espectrometria de Massas em Tandem , Isótopos , Enxofre , Isótopos de Enxofre/análise
4.
Nat Commun ; 12(1): 4403, 2021 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-34285238

RESUMO

Sulfur cycling is ubiquitous in sedimentary environments, where it mediates organic carbon remineralization, impacting both local and global redox budgets, and leaving an imprint in pyrite sulfur isotope ratios (δ34Spyr). It is unclear to what extent stratigraphic δ34Spyr variations reflect local aspects of the depositional environment or microbial activity versus global sulfur-cycle variations. Here, we couple carbon-nitrogen-sulfur concentrations and stable isotopes to identify clear influences on δ34Spyr of local environmental changes along the Peru margin. Stratigraphically coherent glacial-interglacial δ34Spyr fluctuations (>30‰) were mediated by Oxygen Minimum Zone intensification/expansion and local enhancement of organic matter deposition. The higher resulting microbial sulfate reduction rates led to more effective drawdown and 34S-enrichment of residual porewater sulfate and sulfide produced from it, some of which is preserved in pyrite. We identify organic carbon loading as a major influence on δ34Spyr, adding to the growing body of evidence highlighting the local controls on these records.


Assuntos
Bactérias Anaeróbias/metabolismo , Sedimentos Geológicos/microbiologia , Ferro/metabolismo , Oxigênio/metabolismo , Sulfetos/metabolismo , Enxofre/metabolismo , Carbono/metabolismo , Ciclo do Carbono , Geografia , Sedimentos Geológicos/análise , Sedimentos Geológicos/química , Ferro/química , Oxirredução , Peru , Sulfetos/química , Isótopos de Enxofre/análise
5.
FEMS Microbiol Lett ; 368(12)2021 06 24.
Artigo em Inglês | MEDLINE | ID: mdl-34151347

RESUMO

Kinetics of thiosulfate oxidation, product and intermediate formation, and 34S fractionation, were studied for the members of Alphaproteobacteria Paracoccus sp. SMMA5 and Mesorhizobium thiogangeticum SJTT, the Betaproteobacteria member Pusillimonas ginsengisoli SBO3, and the Acidithiobacillia member Thermithiobacillus sp. SMMA2, during chemolithoautotrophic growth in minimal salts media supplemented with 20 mM thiosulfate. The two Alphaproteobacteria oxidized thiosulfate directly to sulfate, progressively enriching the end-product with 34S; Δ34Sthiosulfate-sulfate values recorded at the end of the two processes (when no thiosulfate was oxidized any further) were -2.9‰ and -3.5‰, respectively. Pusillimonas ginsengisoli SBO3 and Thermithiobacillus sp. SMMA2, on the other hand, oxidized thiosulfate to sulfate via tetrathionate intermediate formation, with progressive 34S enrichment in the end-product sulfate throughout the incubation period; Δ34Sthiosulfate-sulfate, at the end of the two processes (when no further oxidation took place), reached -3.5‰ and -3.8‰, respectively. Based on similar 34S fractionation patterns recorded previously during thiosulfate oxidation by strains of Paracoccus pantotrophus, Advenella kashmirensis and Hydrogenovibrio crunogenus, it was concluded that progressive reverse fractionation, enriching the end-product sulfate with 34S, could be a characteristic signature of bacterial thiosulfate oxidation.


Assuntos
Proteobactérias/metabolismo , Isótopos de Enxofre/metabolismo , Tiossulfatos/metabolismo , Crescimento Quimioautotrófico , Cinética , Oxirredução , Filogenia , Proteobactérias/classificação , Proteobactérias/genética , Sulfatos/química , Sulfatos/metabolismo , Isótopos de Enxofre/química
6.
PLoS One ; 16(5): e0250383, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33951062

RESUMO

Sulfur isotope composition of organic tissues is a commonly used tool for gathering information about provenance and diet in archaeology and paleoecology. However, the lack of maps predicting sulfur isotope variations on the landscape limits the possibility to use this isotopic system in quantitative geographic assignments. We compiled a database of 2,680 sulfur isotope analyses in the collagen of archaeological human and animal teeth from 221 individual locations across Western Europe. We used this isotopic compilation and remote sensing data to apply a multivariate machine-learning regression, and to predict sulfur isotope variations across Western Europe. The resulting model shows that sulfur isotope patterns are highly predictable, with 65% of sulfur isotope variations explained using only 4 variables representing marine sulfate deposition and local geological conditions. We used this novel sulfur isoscape and existing strontium and oxygen isoscapes of Western Europe to apply triple isotopes continuous-surface probabilistic geographic assignments to assess the origin of a series of teeth from local animals and humans from Brittany. We accurately and precisely constrained the origin of these individuals to limited regions of Brittany. This approach is broadly transferable to studies in archaeology and paleoecology as illustrated in a companion paper (Colleter et al. 2021).


Assuntos
Arqueologia , Isótopos de Oxigênio/análise , Isótopos de Estrôncio/análise , Isótopos de Enxofre/análise , Europa (Continente) , Geografia
7.
Isotopes Environ Health Stud ; 57(3): 281-300, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33855926

RESUMO

As demand for regional and organically produced foodstuff has increased in Europe, the need has arisen to verify the products' origin and production method. For food authenticity tracking (production method and origin), we examined 286 samples of wheat (Triticum aestivum), potatoes (Solanum tuberosum), and apples (Malus domestica) from different regions in Germany for their stable isotope compositions of oxygen, hydrogen, carbon, nitrogen and sulphur. Single-variate authentication methods were used. Suitable isotope tracers to determine wheat's regional origin were δ18O and δ34S. δ13C helped to distinguish between organic and conventional wheat samples. For the separation of the production regions of potatoes, several isotope tracers were suitable (e.g. δ18O, δ2H, δ15N, δ13C and δ34S isotopes in potato protein), but only protein δ15N was suitable to differentiate between organic and conventional potato samples. For the apple samples, 2H and 18O isotopes helped to identify production regions, but no significant statistical differences could be found between organically and conventionally farmed apples. For food authenticity tracking, our study showed the need to take the various isotopes into account. There is an urgent need for a broad reference database if isotope measurements are to become a main tool for determining product's origin.


Assuntos
Análise de Alimentos/métodos , Isótopos/análise , Malus/química , Solanum tuberosum/química , Triticum/química , Isótopos de Carbono/análise , Deutério/análise , Alemanha , Isótopos de Nitrogênio/análise , Agricultura Orgânica , Isótopos de Oxigênio/análise , Isótopos de Enxofre/análise
8.
Nature ; 592(7853): 232-236, 2021 04.
Artigo em Inglês | MEDLINE | ID: mdl-33782617

RESUMO

The rise of atmospheric oxygen fundamentally changed the chemistry of surficial environments and the nature of Earth's habitability1. Early atmospheric oxygenation occurred over a protracted period of extreme climatic instability marked by multiple global glaciations2,3, with the initial rise of oxygen concentration to above 10-5 of the present atmospheric level constrained to about 2.43 billion years ago4,5. Subsequent fluctuations in atmospheric oxygen levels have, however, been reported to have occurred until about 2.32 billion years ago4, which represents the estimated timing of irreversible oxygenation of the atmosphere6,7. Here we report a high-resolution reconstruction of atmospheric and local oceanic redox conditions across the final two glaciations of the early Palaeoproterozoic era, as documented by marine sediments from the Transvaal Supergroup, South Africa. Using multiple sulfur isotope and iron-sulfur-carbon systematics, we demonstrate continued oscillations in atmospheric oxygen levels after about 2.32 billion years ago that are linked to major perturbations in ocean redox chemistry and climate. Oxygen levels thus fluctuated across the threshold of 10-5 of the present atmospheric level for about 200 million years, with permanent atmospheric oxygenation finally arriving with the Lomagundi carbon isotope excursion at about 2.22 billion years ago, some 100 million years later than currently estimated.


Assuntos
Atmosfera/química , Oxigênio/análise , Oxigênio/história , Isótopos de Carbono/análise , Carbonatos/análise , Clima , Ecossistema , Sedimentos Geológicos/química , História Antiga , Oceanos e Mares , Oxirredução , Água do Mar/química , África do Sul , Isótopos de Enxofre/análise , Fatores de Tempo
9.
PLoS One ; 16(3): e0247569, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33651827

RESUMO

We report here on stable carbon, nitrogen, and sulfur isotope values from bone collagen of human (n = 20) and faunal (n = 11) remains from the Early Neolithic site of Ganj Dareh, Iran, dating to ca. 10,100 cal. BP. Our focus explores how isotope values of human bone vary by age and sex, and evaluates dietary practices at this site. It also provides a baseline for future studies of subsistence in the early Holocene Central Zagros Mountains, from the site with the first evidence for human ovicaprid management in the Near East. Human remains include individuals of all age groups for dietary reconstruction, as well two Ottoman intrusive burials for temporal and cultural comparison. All analyzed individuals exhibited δ13C and δ15N values consistent with a diet based heavily on C3 terrestrial sources. There is no statistically significant difference between the isotopic compositions of the two sexes, though males appear to show larger variations compared to females. Interesting patterns in the isotopic compositions of the subadults suggested weaning children may be fed with supplements with distinctive δ13C values. Significant difference in sulfur isotope values between humans and fauna could be the earliest evidence of transhumance and could identify one older adult male as a possible transhumant shepherd. Both Ottoman individuals had distinctively different δ13C, δ15N, and δ34S values compared to the Neolithic individuals. This is the first large scale analysis of human stable isotopes from the eastern end of the early Holocene Fertile Crescent. It provides a baseline for future intersite exploration of stable isotopes and insight into the lifeways, health, and processes of neolithisation associated with the origins of goat domestication at Ganj Dareh and the surrounding Central Zagros.


Assuntos
Restos Mortais/química , Osso e Ossos/química , Isótopos de Carbono/análise , Colágeno/análise , Isótopos de Nitrogênio/análise , Isótopos de Enxofre/análise , Adolescente , Adulto , Animais , Antropologia Física , Criança , Pré-Escolar , Dieta , Cães , Comportamento Alimentar , Feminino , Raposas , Cabras , História Antiga , Humanos , Lactente , Recém-Nascido , Irã (Geográfico) , Masculino , Pessoa de Meia-Idade , Ovinos , Desmame , Adulto Jovem
10.
PLoS One ; 16(1): e0245069, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33444327

RESUMO

Methanol is often considered as a non-competitive substrate for methanogenic archaea, but an increasing number of sulfate-reducing microorganisms (SRMs) have been reported to be capable of respiring with methanol as an electron donor. A better understanding of the fate of methanol in natural or artificial anaerobic systems thus requires knowledge of the methanol dissimilation by SRMs. In this study, we describe the growth kinetics and sulfur isotope effects of Desulfovibrio carbinolicus, a methanol-oxidizing sulfate-reducing deltaproteobacterium, together with its genome sequence and annotation. D. carbinolicus can grow with a series of alcohols from methanol to butanol. Compared to longer-chain alcohols, however, specific growth and respiration rates decrease by several fold with methanol as an electron donor. Larger sulfur isotope fractionation accompanies slowed growth kinetics, indicating low chemical potential at terminal reductive steps of respiration. In a medium containing both ethanol and methanol, D. carbinolicus does not consume methanol even after the cessation of growth on ethanol. Among the two known methanol dissimilatory systems, the genome of D. carbinolicus contains the genes coding for alcohol dehydrogenase but lacks enzymes analogous to methanol methyltransferase. We analyzed the genomes of 52 additional species of sulfate-reducing bacteria that have been tested for methanol oxidation. There is no apparent relationship between phylogeny and methanol metabolizing capacity, but most gram-negative methanol oxidizers grow poorly, and none carry homologs for methyltransferase (mtaB). Although the amount of available data is limited, it is notable that more than half of the known gram-positive methanol oxidizers have both enzymatic systems, showing enhanced growth relative to the SRMs containing only alcohol dehydrogenase genes. Thus, physiological, genomic, and sulfur isotopic results suggest that D. carbinolicus and close relatives have the ability to metabolize methanol but likely play a limited role in methanol degradation in most natural environments.


Assuntos
Respiração Celular , Desulfovibrio/metabolismo , Genoma Bacteriano , Genômica/métodos , Metanol/metabolismo , Isótopos de Enxofre/análise , Desulfovibrio/genética , Desulfovibrio/crescimento & desenvolvimento , Filogenia , RNA Ribossômico 16S
11.
Rapid Commun Mass Spectrom ; 35(5): e8985, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33085126

RESUMO

RATIONALE: The application of fertilisers to crops can be monitored and assessed using stable isotope ratios. However, the application of marine biofertilisers (e.g., fish, macroalgae/seaweed) on crop stable isotope ratios has been rarely studied, despite widespread archaeological and historical evidence for the use of marine resources as a soil amendment. METHODS: A heritage variety of Celtic bean, similar in size and shape to archaeobotanical macrofossils of Vicia faba L., was grown in three 1 × 0.5 m outdoor plots under three soil conditions: natural soil (control); natural soil mixed with macroalgae (seaweed); and 15 cm of natural soil placed on a layer of fish carcasses (Atlantic cod). These experiments were performed over two growing seasons in the same plots. At the end of each growing season, the plants were sampled, measured and analysed for carbon, nitrogen and sulphur stable isotope ratios (δ13 C, δ15 N, δ34 S). RESULTS: The bean plants freely uptake the newly bioavailable nutrients (nitrogen and sulphur) and incorporate a marine isotopic ratio into all tissues. The bean δ15 N values ranged between 0.8‰ and 1.0‰ in the control experiment compared with 2‰ to 3‰ in the macroalgae crop and 8‰ to 17‰ in the cod fish experiment. Their δ34 S values ranged between 5‰ and 7‰ in the control compared with 15‰ to 16‰ in the macroalgae crop and 9‰ to 12‰ in the cod fish crop. The beans became more 13 C-depleted (δ13 C values: 1-1.5‰ lower) due to crop management practices. CONCLUSIONS: Humans and animals consuming plants grown with marine biofertilisers will incorporate a marine signature. Isotopic enrichment in nitrogen and sulphur using marine resources has significant implications when reconstructing diets and farming practices in archaeological populations.


Assuntos
Isótopos de Carbono/análise , Fertilizantes/análise , Isótopos de Nitrogênio/análise , Solo/química , Isótopos de Enxofre/análise , Vicia faba/química , Animais , Isótopos de Carbono/metabolismo , Produção Agrícola , Dieta , Gadus morhua , Humanos , Isótopos de Nitrogênio/metabolismo , Alga Marinha/química , Isótopos de Enxofre/metabolismo , Vicia faba/crescimento & desenvolvimento , Vicia faba/metabolismo
12.
Nucleic Acids Res ; 49(1): 1-14, 2021 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-33275144

RESUMO

Nucleic acid therapeutics (NATs) have proven useful in promoting the degradation of specific transcripts, modifying gene expression, and regulating mRNA splicing. In each situation, efficient delivery of nucleic acids to cells, tissues and intracellular compartments is crucial-both for optimizing efficacy and reducing side effects. Despite successes in NATs, our understanding of their cellular uptake and distribution in tissues is limited. Current methods have yielded insights into distribution of NATs within cells and tissues, but the sensitivity and resolution of these approaches are limited. Here, we show that nanoscale secondary ion mass spectrometry (NanoSIMS) imaging can be used to define the distribution of 5-bromo-2'-deoxythymidine (5-BrdT) modified antisense oligonucleotides (ASO) in cells and tissues with high sensitivity and spatial resolution. This approach makes it possible to define ASO uptake and distribution in different subcellular compartments and to quantify the impact of targeting ligands designed to promote ASO uptake by cells. Our studies showed that phosphorothioate ASOs are associated with filopodia and the inner nuclear membrane in cultured cells, and also revealed substantial cellular and subcellular heterogeneity of ASO uptake in mouse tissues. NanoSIMS imaging represents a significant advance in visualizing uptake and distribution of NATs; this approach will be useful in optimizing efficacy and delivery of NATs for treating human disease.


Assuntos
Oligonucleotídeos Antissenso/análise , Oligonucleotídeos Fosforotioatos/análise , Espectrometria de Massa de Íon Secundário/métodos , Células 3T3-L1 , Acetilgalactosamina/administração & dosagem , Acetilgalactosamina/análise , Animais , Receptor de Asialoglicoproteína/análise , Césio , Células HEK293 , Células HeLa , Humanos , Rim/química , Rim/ultraestrutura , Fígado/química , Fígado/ultraestrutura , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Eletrônica , Miocárdio/química , Miocárdio/ultraestrutura , Oligonucleotídeos Antissenso/farmacocinética , Oligonucleotídeos Fosforotioatos/farmacocinética , Pseudópodes/química , Pseudópodes/ultraestrutura , RNA Longo não Codificante/antagonistas & inibidores , RNA Longo não Codificante/biossíntese , RNA Longo não Codificante/genética , Frações Subcelulares/química , Enxofre/análise , Isótopos de Enxofre/análise , Distribuição Tecidual
13.
Astrobiology ; 21(1): 103-114, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-33124879

RESUMO

Target lithologies and post-impact hydrothermal mineral assemblages in a new 1.3 km deep core from the peak ring of the Chicxulub impact crater indicate sulfate reduction was a potential energy source for a microbial ecosystem (Kring et al., 2020). That sulfate was metabolized is confirmed here by microscopic pyrite framboids with δ34S values of -5 to -35 ‰ and ΔSsulfate-sulfide values between pyrite and source sulfate of 25 to 54 ‰, which are indicative of biologic fractionation rather than inorganic fractionation processes. These data indicate the Chicxulub impact crater and its hydrothermal system hosted a subsurface microbial community in porous permeable niches within the crater's peak ring.


Assuntos
Microbiota , Sulfatos , Fracionamento Químico , Isótopos de Enxofre/análise
14.
J Agric Food Chem ; 68(39): 10852-10864, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-32893631

RESUMO

An international project developed, quality-tested, and measured isotope-delta values of 10 new food matrix reference materials (RMs) for hydrogen, carbon, nitrogen, oxygen, and sulfur stable isotope-ratio measurements to support food authenticity testing and food provenance verification. These new RMs, USGS82 to USGS91, will enable users to normalize measurements of samples to isotope-delta scales. The RMs include (i) two honeys from Canada and tropical Vietnam, (ii) two flours from C3 (rice) and C4 (millet) plants, (iii) four vegetable oils from C3 (olive, peanut) and C4 (corn) plants, and (iv) two collagen powders from marine fish and terrestrial mammal origins. An errors-in-variables regression model included the uncertainty associated with the measured and assigned values of the RMs, and it was applied centrally to normalize results and obtain consensus values and measurement uncertainties. Utilization of these new RMs should facilitate mutual compatibility of stable isotope data if accepted normalization procedures are applied and documented.


Assuntos
Colágeno/análise , Deutério/análise , Farinha/análise , Mel/análise , Isótopos de Nitrogênio/análise , Isótopos de Oxigênio/análise , Óleos Vegetais/química , Isótopos de Enxofre/análise , Animais , Proteínas de Peixes/análise , Peixes
15.
Astrobiology ; 20(10): 1212-1223, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32985907

RESUMO

Ancient veins of calcium sulfate minerals (anhydrite, bassanite, and gypsum) deposited by subsurface aqueous fluids crosscut fluviolacustrine sedimentary rocks at multiple localities on Mars. Although these veins have been considered an attractive target for astrobiological investigation, their potential to preserve biosignatures is poorly understood. Here, we report the presence of biogenic authigenic pyrite in a fibrous gypsum vein of probable Cenozoic emplacement age from Permian lacustrine rocks in Northwest England. Pyrite occurs at the vein margins and displays a complex interfingering boundary with the surrounding gypsum suggestive of replacive authigenic growth. Gypsum-entombed carbonaceous material of probable organic origin was also identified by Raman spectroscopic microscopy in close proximity to the pyrite. Spatially resolved ion microprobe (SIMS) measurements reveal that the pyrite sulfur isotope composition is consistently very light (δ34SVCDT = -30.7‰). Comparison with the sulfate in the vein gypsum (δ34SVCDT = +8.5‰) indicates a fractionation too large to be explained by nonbiological (thermochemical) sulfate reduction. We infer that the pyrite was precipitated by microorganisms coupling the reduction of vein-derived sulfate with the oxidation of wall-derived organic matter. This is the first evidence that such veins can incorporate biosignatures that remain stable over geological time, which could be detected in samples returned from Mars.


Assuntos
Sulfato de Cálcio , Geologia , Isótopos de Enxofre , Inglaterra , Exobiologia , Marte , Isótopos de Enxofre/análise
16.
Sci Rep ; 10(1): 15463, 2020 09 22.
Artigo em Inglês | MEDLINE | ID: mdl-32963281

RESUMO

Millions of mummified birds serving for religious purpose have been discovered from archeological sites along the Nile Valley of Egypt, in majority ibises. Whether these birds were industrially raised or massively hunted is a matter of heavy debate as it would have a significant impact on the economy related to their supply and cult, and if hunted it would have represented an ecological burden on the birds populations. Here we have measured and analysed the stable oxygen, carbon and radiogenic strontium isotope compositions as well as calcium and barium content of bones along with the stable carbon, nitrogen and sulfur isotope composition of feathers from 20 mummified ibises and birds of prey recovered from various archeological sites of Ancient Egypt. If these migratory birds were locally bred, their stable oxygen, radiogenic strontium and stable sulfur isotopic compositions would be similar to that of coexisting Egyptians, and their stable carbon, nitrogen and oxygen isotope variance would be close, or lower than that of Egyptians. On one hand, isotopic values show that ibises ingested food from the Nile valley but with a higher isotopic scattering than observed for the diet of ancient Egyptians. On the other hand, birds of prey have exotic isotopic values compatible with their migratory behaviour. We therefore propose that most mummified ibises and all the birds of prey analysed here were wild animals hunted for religious practice.


Assuntos
Isótopos de Carbono/análise , Plumas/química , Múmias , Isótopos de Nitrogênio/análise , Isótopos de Oxigênio/análise , Isótopos de Enxofre/análise , Animais , Animais Selvagens , Aves , Antigo Egito
17.
Environ Pollut ; 267: 115444, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32866874

RESUMO

The high frequency of acid rain in southern China has captured public and official concern since 1980s. Subsequently, gas emission reduction measures have been implemented to improve the air quality. Variations in SO2 emission intensities can influence the sulfur and oxygen isotopic compositions of sulfate in rainwater, since atmospheric sulfate is mainly formed via the oxidation of sulfur gases from natural and anthropogenic sources. To evaluate the impacts of emission reduction measures on atmospheric sulfate, the seasonal and long-term trends in stable isotopic compositions of sulfate in rainwater in Guizhou province, southwestern China have been investigated based on rainwater samples collected from June 2016 to June 2018 and literature investigation (2000-2010).The results reveal that coal combustion remains a major contributor to sulfate in rainwater, although its SO2 emission has significantly decreased over the past two decades. The δ34Ssulfate and δ18Osulfate values in rainwater are negatively correlated and have significant seasonal changes. The seasonality in δ34Ssulfate has been interpreted as due to the changes in contributions of dimethyl sulfide and coal combustion, while the seasonal pattern of δ18Osulfate is consistent with that of δ18Owater values, indicating sulfate in rainwater is mainly formed by heterogeneous oxidation of SO2. Combined with the data from previous studies (Xiao and Liu, 2002; Liu, 2007; Xiao et al., 2009; Xiao et al., 2014), we found that the volume weighted mean δ34S values of sulfate in rainwater in Guizhou province show a marked increase between 2001 and 2018, indicating that the 34S-depleted SO2 emission from coal combustion has declined during this period. Furthermore, the synchronous changes in δ34S values, sulfate concentration and pH values of rainwater suggest that the frequency of acid rain in Guizhou province has dropped over the past two decades, which is likely to result from the emission reduction measures taken in Guizhou province.


Assuntos
Chuva Ácida , Chuva Ácida/análise , China , Monitoramento Ambiental , Isótopos de Oxigênio/análise , Enxofre , Isótopos de Enxofre/análise
18.
PLoS One ; 15(8): e0237105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32776947

RESUMO

Studying the isotope variability in fast-growing human tissues (e.g., hair, nails) is a powerful tool to investigate human nutrition. However, interpreting the controls of this isotopic variability at the population scale is often challenging as multiple factors can superimpose on the isotopic signals of a current population. Here, we analyse carbon, nitrogen, and sulphur isotopes in hair from 590 Canadian resident volunteers along with demographics, dietary and geographic information about each participant. We use a series of machine-learning regressions to demonstrate that the isotopic values in Canadian residents' hair are not only influenced by dietary choices but by geographic controls. First, we show that isotopic values in Canadian residents' hair have a limited range of variability consistent with the homogenization of Canadian dietary habits (as in other industrialized countries). As expected, some of the isotopic variability within the population correlates with recorded individual dietary choices. More interestingly, some regional spatial patterns emerge from carbon and sulphur isotope variations. The high carbon isotope composition of the hair of eastern Canadians relative to that of western Canadians correlates with the dominance of corn in the eastern Canadian food-industry. The gradient of sulphur isotope composition in Canadian hair from coast to inland regions correlates with the increasing soil pH and decreasing deposition of marine-derived sulphate aerosols in local food systems. We conclude that part of the isotopic variability found in the hair of Canadian residents reflects the isotopic signature associated with specific environmental conditions and agricultural practices of regional food systems transmitted to humans through the high consumption rate of intra-provincial food in Canada. Our study also underscores the strong potential of sulphur isotopes as tracers of human and food provenance.


Assuntos
Variação Biológica da População , Isótopos de Carbono/análise , Cabelo/química , Isótopos de Nitrogênio/análise , Isótopos de Enxofre/análise , Adulto , Canadá , Dieta/estatística & dados numéricos , Feminino , Humanos , Masculino
19.
Forensic Sci Int ; 316: 110455, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32858379

RESUMO

This article presents data on carbon (C), nitrogen (N), and sulfur (S) isotopic composition of human hair collected throughout Mexico. The recorded values ranged from -18.3‰ to -12.8‰ for δ13C, 6.8‰ to 10.8‰ for δ15N and from 2.7‰ to 8.0‰ for δ34S. The socioeconomic covariates explored in this study showed, in part strong correlations with the recorded isotope values. Furthermore, these three isotope systems provide records of the dietary preferences and practices and also showed some spatial variation. This study detected geospatial patterning in the δ13C values of hair samples from Mexico as well as significant correlations with socioeconomic factors. No geospatial variation was detected in the δ15N and δ34S values, however, socioeconomic correlations were found. A δ13C isoscape was generated using a GIS approach, which provides a tool to narrow down region-of-origin predictions (in combination with other isotope systems) and to document the travel history of unidentified individuals.


Assuntos
Isótopos de Carbono/análise , Cabelo/química , Isótopos de Nitrogênio/análise , Isótopos de Enxofre/análise , Sistemas de Informação Geográfica , Geografia , Humanos , México , Áreas de Pobreza , Chuva , Fatores Socioeconômicos , Temperatura , Topografia Médica
20.
Appl Radiat Isot ; 163: 109220, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32561057

RESUMO

The 33S(n,α)30Si reaction was proposed as cooperative neutron capturer to 10B(n,α)7Li in Neutron Capture Therapy (NCT). At that moment, the available 33S(n,α)30Si cross-section data were scarce and discrepant in key energy ranges for its use in NCT. Since then, three experiments have been carried out at n_TOF facility at CERN and at Institut Laue-Langevin. These new data are used for the calculation of the dose rate on ICRU-4 tissue by using kerma factors, a simplified model of tissue and a 13.45 keV neutron beam, energy of the most important 33S(n,α)30Si resonance. A significant enhancement of the dose rate due to the presence of 33S is shown. In spite of the limitations, the cooperative action of 33S and 10B is an interesting possibility to be studied for accelerator-based neutron sources with non-moderated neutrons.


Assuntos
Terapia por Captura de Nêutron de Boro/métodos , Boro/química , Isótopos de Enxofre/química , Humanos , Método de Monte Carlo , Dosagem Radioterapêutica
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