Search Results (400)

The increasing frequency and intensity of hotter droughts are driving widespread forest dieback, yet the role of tree nutritional status in drought-induced growth dieback remains poorly understood. We investigated how nutrient composition across tissues (leaves, wood) relates to water use patterns and growth resilience in rear-edge populations of Scots pine (Pinus sylvestris L.) in Northeastern Spain. Using a multi-proxy approach, we combined analyses of foliar and sapwood nutrient concentrations, stable isotopes (δ¹³C, δ¹⁸O), and dendrochronological indicators across contrasting tree vigor classes. Defoliated trees exhibited pronounced shifts in elemental composition, including depletion of foliar K and increased concentrations of Ca, S, and Fe, alongside higher intrinsic water use efficiency and reduced growth resistance to drought. In contrast, the sapwood elemental composition was less responsive to defoliation but showed stronger associations with isotopic signals and drought resilience, suggesting its integrative role in tree functioning. Coordination of nutrient concentrations between tissues was limited, suggesting organ-specific regulation of nutrient allocation under drought stress. Our results reveal that nutrient imbalances are linked to water–carbon dynamics and drought responses and emphasize the importance of considering multi-organ nutrient dynamics to improve our understanding of long-term nutritional imbalances during drought-induced forest dieback. Full article

Marginal lacustrine systems are highly sensitive archives of hydrological fluctuations, climatic variability, and changes in sediment supply in continental basins. The Alagöz Formation (Late Miocene–Pliocene) exposed in the Haymana–Polatlı Basin, Central Anatolia, was investigated through integrated sedimentological, mineralogical, geochemical, and stable isotope analyses to constrain provenance, weathering history, and lacustrine hydrological variability. Facies analysis reveals a transition from alluvial–fluvial systems to a shallow marginal lacustrine environment subjected to short-term hydrological fluctuations. Mineralogical and geochemical data indicate that sedimentation occurred within a mixed carbonate–siliciclastic lacustrine system controlled by variable lake-water chemistry. Detrital mineral assemblages indicate contributions from metamorphic source rocks. Trace-element and REE signatures suggest derivation mainly from felsic-to-intermediate continental sources. Reworked carbonate fragments and fossil debris indicate recycling of older carbonate units. The occurrence of calcite, dolomite, and protodolomite reflects variable Mg/Ca ratios, whereas clay mineral assemblages record shifts between detrital input during relatively humid phases and chemically concentrated conditions. Palygorskite occurrence indicates localized and episodic alkaline conditions associated with short-lived evaporative concentration. Weathering indices (CIA, CIW, PIA, and ICV) suggest low-to-moderate chemical weathering and compositionally immature sediments, consistent with transitional humid to semi-arid climatic conditions. Trace-element systematics also indicate a minor mafic contribution to the detrital source. Stable isotope values (δ¹³C: −7.05‰ to +2.82‰; δ¹⁸O: −8.60‰ to −2.94‰ VPDB) and their weak correlation (r = 0.34) support a shallow, hydrologically dynamic lacustrine system dominated by freshwater input but episodically influenced by evaporative concentration. Taken together, the Alagöz Formation records a sensitive marginal lacustrine system shaped by short-term hydrological fluctuations. These findings provide a useful analog for understanding hydrologically sensitive marginal lacustrine systems developed in post-collisional continental basins under fluctuating semi-arid climatic conditions. Full article

As part of a fundamental and comprehensive monitoring and conservation of the tomb of Emperor Otto the Great in the cathedral of Magdeburg, the question of the provenance of the marble cover slab of the sarcophagus was investigated. Within the restoration activities, two samples of the slab were taken for scientific provenance analyses, one sample of the white marble and another of the irregular grey bands. The following investigations were used for this purpose: analysis of the stable isotopes of O and C, and chemical analysis of a large number of trace elements, resulting in a large number of variables. For the simultaneous evaluation of these numerical results, statistical multivariate analysis was used for comparing the results with our database of approximately 7000 samples from ancient marble quarries and the data being referenced in this investigation are published and listed here. The results obtained clearly identify the quarries of Prokonnesos in the Sea of Marmara as the most probable source of the examined slab. This is in perfect agreement with petrographic analyses carried out on these samples. Full article

Tetrastigma hemsleyanum Diels et Gilg is a high-value edible and medicinal homologous plant, routinely grown under conventional field or greenhouse production systems across Asia. However, mislabeling of conventional products as the rarer (and more expensive) wild version may occur for financial gain. In this study, stable isotopes (δ¹³C, δ¹⁵N, δ²H, and δ¹⁸O) and metal contents (Cr, Cu, Ni, As, Cd, Pb) were used to characterize plant tissues (tuber root, stem, leaf) and corresponding soils originating from simulated-wild-cultivated (WC) and greenhouse-cultivated (GC) pot trials using the same soil. Carbon and nitrogen isotopes served as key indicators for distinguishing GC and WC products. Specifically, δ¹³C values of GC plant tissues were 1.4 to 2.4‰ more positive than those of WC plant tissues (p < 0.05), and δ¹⁵N values in GC tissues were 2.7 to 4.6‰ more positive than δ¹⁵N in WC tissues (p < 0.01). Lower δ¹⁵N values observed in WC products indicate slower nitrogen turnover compared with GC products. Soil metal concentrations had significant differences between the two cultivation systems, but only limited effects on metal bioconcentration factors (BCFs) and translocation factors (TFs) in T. hemsleyanum tissues. Pb and Cd concentrations in root tissues had large differences between cultivation systems, and carbon dynamics in GC plants were more negatively affected by Pb levels in soils. These findings provide the first investigation of T. hemsleyanum grown under different cultivation practices and establish a scientific basis for distinguishing other wild or simulated-wild labeled food and medicinal plant products from conventionally grown products in future studies. Full article

The Chutuan and Jiashan fluorite deposits are situated in the Donghai–Linshu area within the southwestern segment of the Sulu ultrahigh–pressure metamorphic belt. Both deposits share similar mineralization characteristics, with fluorite veins strictly controlled by fault structures and associated with mineral assemblages comprising fluorite, barite, quartz, and calcite. Two mineralization stages have been identified in both deposits: Stage I (quartz–fluorite–barite stage), representing the main ore–forming event, and Stage II (quartz–barite–calcite stage). This study focuses on integrated geochemical and geochronological analyses of fluorite from Stage I, providing new constraints on the genesis and metallogenic processes of these deposits. Direct Sm–Nd isotopic dating of fluorite yields an isochron age of 104 ± 16 Ma, indicating that mineralization occurred during the late Early Cretaceous. Fluid inclusion and stable isotope studies reveal that the ore–forming fluids constitute a complex hydrothermal system characterized by a wide temperature range (112–324 °C) and variable salinities (0.18–21.87 wt% NaCl eq.). The H–O isotopic compositions exhibit a distinct latitudinal trend, supporting a dominant meteoric water component. However, the presence of high–temperature, high–salinity fluid inclusions, along with a shift in some δD values towards the magmatic water field, suggests episodic mixing between meteoric water and deep–seated magmatic–hydrothermal fluids. Sr–Nd isotopic data (⁸⁷Sr/⁸⁶Sr = 0.711785–0.713424; εNd(t)= −27.7 to −27.5) potentially demonstrate that the ore–forming materials (Ca and REEs) were not derived from coeval magmatic rocks. Instead, they were primarily leached from the Precambrian Donghai Group metamorphic complex through extensive water–rock interaction. Based on these findings, the Chutuan and Jiashan deposits are classified as hydrothermal vein–type systems. Fluorite precipitation was governed by a combination of fluid cooling, water–rock interaction, and fluid mixing. Finally, a metallogenic model is established, offering important insights into the genesis of fluorite mineralization in the Sulu Orogenic Belt and analogous geological settings in eastern China. Full article

Ophicarbonates provide an important natural record of mineral carbonation during serpentinization of ultramafic rocks and therefore offer insight into the mechanisms and limits of CO₂ fixation in low-temperature geological environments. This paper presents a synthesis and process-oriented reinterpretation of stable-isotope published and previously unpublished data, petrographic, and mineralogical evidence for carbonate formation under fluid-limited serpentinization conditions. Using mineralogical constraints together with a compiled δ¹³C–δ¹⁸O dataset that includes legacy measurements from the 1980s–1990s, we evaluate how multi-stage carbonate precipitation reflects evolving water–rock ratio, redox state, transport limitation, and deformation-controlled permeability. Particular attention is given to systematic differences between vein-hosted carbonates and dispersed intergranular or scattered-grain ophicarbonates, as these textural–isotopic relationships help identify fluid flux, carbon source, and reaction progress in ultramafic systems. The analysis shows that carbonation does not proceed uniformly but is restricted to overlapping reactive windows controlled by fluid availability, nucleation kinetics, and permeability evolution. These constraints help explain why carbonation may either intensify or stall during progressive serpentinization. The Author further discuss why kinetic barriers and Mg–Ca partitioning may redirect carbonate mineralogy toward calcite or metastable Mg-rich phases even where dolomite or magnesite may be thermodynamically favored. The results highlight the importance of coupling isotopic signatures with petrographic context in reconstructing carbonation pathways and provide a broader framework for understanding natural mineral sequestration of carbon in heterogeneous serpentinite systems. Full article

Natural mineral waters hosted in volcanic terrains are globally significant, but the co-enrichment mechanisms of metasilicate and strontium remain poorly understood. Here we investigate a Jurassic volcanic-hosted mineral water source in eastern China using hydrochemical analysis, ¹⁴C dating, stable isotopes, and structural analysis. The groundwater is of Ca–Mg–HCO₃ type with slightly alkaline pH (7.44–7.63). Metasilicate (26.4–32.9 mg/L) and strontium (0.40–0.83 mg/L) co-enrichment is governed by plagioclase weathering in a bicarbonate-dominated, weakly alkaline environment where ${\mathrm{S}\mathrm{r}\mathrm{H}\mathrm{C}\mathrm{O}}_3^{+}$ ion pairs enhance strontium mobility. Pearson-corrected ¹⁴C ages of 3900–4900 years reveal that millennial-scale residence time is critical for sufficient water-rock interaction and attainment of regulatory thresholds. A conduit-barrier system formed by NW-trending extensional-shear and NNE-trending compressional-shear faults controls groundwater flow paths and residence times, leading to systematic inter-well hydrochemical differentiation. These findings provide a theoretical basis for the genetic identification, potential evaluation, and sustainable management of high-quality mineral water resources in volcanic terrains. Full article

This study explored the application of carbon stable isotopes for tracing the geographical origin of Monochamus alternatus, an insect vector responsible for spreading pine wilt disease. The primary vector of pine wilt disease, an aggressive disease caused by the pine wood nematode and affecting pine forests, is Monochamus alternatus. Samples of Monochamus alternatus were collected from 12 provinces across China, and their carbon isotope ratios (δ¹³C) were measured. By analyzing the correlation between these ratios and various environmental factors, including latitude, longitude, altitude, and bioclimatic conditions, it was found that precipitation seasonality and solar radiation were the most important factors influencing the carbon isotope ratio of Monochamus alternatus. The spatial distribution of Monochamus alternatus carbon isotopes in China was predicted using the co-Kriging interpolation method, incorporating these two environmental variables. The findings revealed a gradient in the carbon isotope ratio of Monochamus alternatus, which could help differentiate the species across various geographical regions in China. Full article

European pork production pursues traceability and authenticity to ensure animal welfare, food safety, and support products with geographical indications. This study reports a European survey integrating stable isotope ratios (δ¹³C, δ¹⁵N, δ³⁴S, δ¹⁸O, δ²H) and multi-element profiling using IRMS and ICP-MS, on 612 samples collected across Denmark, Poland, Italy, and Spain, with diverse production systems, breeds, feeding, and slaughter ages. Geographical and climatic gradients influenced δ²H and δ¹⁸O, which ranged from −111‰ to −89‰ in samples from Denmark and Spain and from 13.3‰ to 16.0‰ in samples from Italy and Spain, respectively. In selected farms, δ¹³C ranged from −22.7‰ to −17.0‰ depending on diet composition based on C₃ and C₄ plants. The wide variability in pig management practices suggested that δ¹⁵N (2.50 ÷ 4.96‰) increased with slaughter age and was positively correlated with Fe (3.38 ÷ 8.39 mg/kg) and Zn (9.39 ÷ 23.6 mg/kg). Most mineral components were mainly driven by feed formulation and supplementation. Principal component analysis (PCA) showed that samples were grouped based on their origin and husbandry system, confirming the key role of isotopic and elemental markers for the development of a database supporting the pork supply chains across Europe. Full article

Pacific white shrimp (Litopenaeus vannamei) is a major aquaculture product worldwide. For consumers, discriminating domestic from imported sources of shrimp meat, and individual domestic sources, can be highly desirable because of the different meat quality and environmental contamination from geographically different origins of shrimp. This study evaluated the potential of stable isotope analysis (δ¹³C, δ¹⁵N, δ²H, δ¹⁸O) with chemometric models to authenticate the origins of Pacific white shrimp sold in China. Shrimp samples from domestic (Guangxi, Fujian, Shandong, Inner Mongolia) and foreign (Ecuador) sources were analyzed, using statistical analyses. The four-isotope model achieved 89.3% cross-validation accuracy in distinguishing domestic and foreign shrimp, with an overall prediction Area Under the Curve (AUC) of 0.901 (95% CI: 0.819–0.983)—significantly outperforming single-isotope models. Differences in δ¹³C and δ¹⁵N reflected feed source variations, while δ²H and δ¹⁸O (Variable Importance in the Projection (VIP) > 1, key discriminatory indicators) mirrored geographic environmental difference. Although δ¹⁵N did not differ significantly among groups, the combination of all four isotopes reduced limitations of individual δ²H/δ¹⁸O use. This approach enhanced the precision, reliability, and applicability of stable isotope analysis for origin authentication by leveraging complementary isotopic data and robust statistical frameworks. These findings demonstrate the proposed model’s potential as a cost-effective, copyright-compliant framework for shrimp origin authentication, with implications for isotopic traceability across food science fields. Full article

Background: Stable isotope-based analytical methods have brought about a significant transformation in the study of energy nutrient metabolism, enabling precise in vivo measurement of metabolic fluxes at systemic, tissue, and organ-specific levels in both healthy and diseased states. The regulation of these metabolic fluxes is governed by dynamic interactions between proteins, lipids, carbohydrates, and their precursors—such as glucose, fatty acids, and amino acids—as well as final metabolic products. Discussion: Advanced analytical technologies, including nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS), which can offer enhanced precision, have been developed for investigating nutrient metabolism and fluxes in humans, providing precise information on metabolic pathways. These techniques have primarily utilized stable isotopes, such as ²H, ¹³C, ¹⁵N, and ¹⁸O, which have largely replaced radioactive isotopes and are now central to metabolic research. These isotopes have been used to label glucose, fatty acids, or amino acids—the main biomolecular precursors—enabling detailed investigation at systemic, tissue, and organ-specific levels of carbohydrate, lipid, and protein metabolism, and revealing pathway alterations associated with diseases conditions, such as diabetes, non-alcoholic fatty liver disease, cardiovascular disorders, and cancer. The use of deuterium oxide (D₂O) has allowed for long-term metabolic studies, providing a cost-effective and less invasive means to monitor metabolic changes over days to months. Total daily energy expenditure can be measured in free living conditions by the doubly stable isotopes ²H- and ¹⁸O-labeled water method. Stable isotope tracing, combined with advanced imaging and modeling, has also been instrumental in assessing body composition, energy expenditure, and nutrient bioavailability. Collectively, these methods have expanded our understanding of human physiology and disease, supporting the development of novel diagnostic tools, the identification of new biomarkers, and the tailoring of nutritional and therapeutic interventions. Conclusions: This review aimed to provide an overview of the applications of stable isotopes for the study of energy nutrient metabolic pathways. The ongoing integration of stable isotope approaches with artificial intelligence, omics technologies, and miniaturized detection techniques could promise to further refine our understanding of human metabolism and drive advances in personalized medicine. Full article

Multivariate carbon and oxygen stable isotope analyses combined with chemometric methods were employed to investigate Aquilaria sinensis samples collected from six major regions in China (Honghe Hani and Yi Autonomous Prefecture and Xishuangbanna Dai Autonomous Prefecture in Yunnan Province; Zhongshan City and Maoming City in Guangdong Province; and Danzhou City and Chengmai County in Hainan Province). Isotopic δ-values were analyzed across different wood parts (longitudinal and north–south orientations), chemical fractions (de-extracted wood and α-cellulose), and geographical origins. Principal Component Analysis (PCA), Linear Discriminant Analysis (LDA), Support Vector Machine (SVM), Decision Tree, and Random Forest were applied to screen and classify the samples. Four discriminant models were successfully established, achieving a maximum accuracy of 85.7% for distinguishing Aquilaria sinensis from different regions, and 88.1% for discrimination at the provincial level. These results demonstrate that stable isotope signatures, when combined with chemometrics, provide a reliable technical approach for the traceability of incense wood and offer a reference framework for verifying the authenticity of Agarwood and related plant-derived materials. Full article

The northern Vietnam shelf, particularly the area adjacent to the Red River Fault Zone, is characterized by complex geology and active neotectonics. However, the patterns of degassing and the origins of hydrocarbon gases in this region remain poorly understood. In particular, the potential links between deep-seated fluid migration, fault systems, and gas anomalies in island groundwater systems have not been systematically investigated. This study presents preliminary results of dissolved methane, its homologues (C₂–C₅), helium, hydrogen, and carbon dioxide measurements in groundwater from Co To Island (Northern Vietnam), with the aim of identifying gas origins and assessing structural controls on fluid migration. A significant methane anomaly was discovered, with concentrations reaching up to 10% by volume in the northwestern part of the island. The hydrocarbon homologous series is traced up to pentane (C₅), and CO₂ content is also elevated, with a maximum of 5.4%. The average He concentration of 10.8 ppm significantly exceeds atmospheric equilibrium values, with maximum recorded concentrations of 18 ppm for He and 34.5 ppm for H₂. Stable carbon isotope analysis of methane (δ¹³C-CH₄ values ranging from −50.2‰ to −49.7‰ VPDB), combined with the presence of a complete C₁–C₅ hydrocarbon series and elevated mantle/crustal tracers (He, H₂), indicates a predominantly thermogenic/metamorphogenic origin for the gases, ruling out a purely biogenic source. The spatial distribution of anomalies is structurally controlled, closely associated with the NE-SW trending Co To Fault system and its intersections with subsidiary faults, as corroborated by recent electrical resistivity tomography data. These findings indicate intensive, focused gas leakage from a deep-seated source, likely related to thermogenic/metamorphic processes and active fault-mediated degassing. The results highlight the significant hydrocarbon potential of the region and underscore the critical role of neotectonic activity in controlling fluid migration pathways in island aquifer systems. Full article

Monitoring of stable isotopes in throughfall (δ¹⁸O, δ²H) and meteorological parameters is a valuable tool for researching forest hydrology, particularly during extreme events like droughts and floods. This study presents the first systematic analysis of air temperature and precipitation changes over the past 65 years in two Slovenian lowland forests: Murska šuma and Krakovski gozd, in combination with isotopic composition research of throughfall. The observed rising air temperatures and altered precipitation patterns are reflected in the isotopic composition of throughfall. Over the last 65 years, air temperature has increased by approximately 2.5 °C. Although total annual precipitation amounts have remained relatively stable, in the last 35 years there is a notable decrease in precipitation in growing season and an increase during the dormant season, influenced by air masses of Mediterranean origin. Extreme drought in 2022 and flood in 2023 are confirmed by the Standardized Precipitation Index and isotopic variations in throughfall due to fractionation processes. Annual variability appears as seasonal changes, with sine-curve amplitudes of 3.71‰ in Krakovski gozd and 3.61‰ in Murska šuma. Together with the Local Meteoric Water Lines, these patterns support estimates of groundwater mean residence time and the origin of water used by trees. Full article

Accurately tracing the geographical origin of Zanthoxylum schinifolium Sieb. et Zucc. is important for brand authentication, quality control, and food safety assurance. In this study, the stable isotope ratios (δ¹³C, δ¹⁵N, δ²H, δ¹⁸O) and the contents of 20 elements were analyzed in samples from three major production regions. Significant differences (p < 0.05) were observed in δ¹³C, δ²H, δ¹⁸O and most elemental profiles across origins. Chemometric methods—including principal component analysis (PCA), orthogonal partial least squares-discriminant analysis (OPLS-DA), and linear discriminant analysis (LDA)—were applied to classify samples by geographical origin. OPLS-DA identified key discriminators (VIP > 1) such as Ca, δ¹³C, Mg, δ²H, B, δ¹⁸O, Cr, Ni, Na, Pb, As, Co, Se, and Zn, achieving a classification accuracy of 96.8%. LDA based on the combined isotope and element datasets showed even higher performance, with an original discrimination rate of 98.4% and a cross-validated rate of 92.8%. The results demonstrate that integrating stable isotope and multi-element fingerprints with supervised classification models provides a reliable and effective approach for verifying the geographical origin of Zanthoxylum schinifolium, supporting its use in traceability systems and fair trade practices. Full article