Search Results (266)

Protonic ceramic electrochemical cells (PCECs), including protonic ceramic fuel cells, electrolysis cells and reversible cells, have attracted increasing attention as efficient solid-state devices for electricity generation, hydrogen production and chemical conversion at intermediate temperatures. Recent advances in electrolyte thinning, electrode nanostructuring and interface engineering have enabled remarkable device performance, including reversible operation at 500–650 °C, operation below 450 °C, and expanded fuel flexibility toward hydrogen, ammonia and methane-containing feeds. However, the working-state mechanisms governing their performance and durability remain insufficiently understood. In particular, proton incorporation, surface hydration, proton exchange, proton-coupled oxygen reduction/evolution, electrode reconstruction and buried interface degradation are highly dynamic processes that cannot be fully resolved by ex situ or post-mortem characterization. Operando characterization provides a powerful route to bridge this knowledge gap by directly correlating structural, chemical and electrochemical evolution under realistic temperature, steam, gas atmosphere and electrochemical bias. In this review, we summarize recent progress in operando and in situ characterization of PCECs, with emphasis on vibrational spectroscopy, X-ray-based techniques, neutron methods, electron microscopy and electrochemical diagnostics. We discuss how operando DRIFTS and H/D isotope exchange reveal voltage-dependent proton exchange kinetics, how operando Raman captures oxygen-electrode surface reconstruction, how X-ray and neutron methods probe redox chemistry and proton dynamics, and how EIS/DRT analysis links structural changes to reaction resistance. We further highlight current challenges, including limited access to buried interfaces, difficulty in quantifying protonic defects, insufficient multimodal correlation and the lack of standardized operando cell configurations. Finally, we propose future directions based on isotope-resolved spectroscopy, multimodal operando platforms, AI-assisted spectral/impedance analysis and theory-guided interpretation. This review aims to establish a working-state mechanistic framework for rationally designing durable, high-performance PCECs. Full article

Modern scientific research approaches to studying the hydrological cycle of water in nature, in addition to the mathematical modeling of hydrological–hydraulic processes that have expanded in recent years, increasingly include isotope hydrology on a global scale. This paper presents the preliminary results of research in the Vardar River basin. The research is in the field of isotope hydrology with the analysis of stable isotopes of hydrogen (δ²H) and oxygen (δ¹⁸O) in precipitation (P), surface water (SW) and groundwater (GW). For this purpose, a network for taking water samples in the Vardar River basin has been established. The isotopic composition of precipitation shows a relatively wide variability, with δ²H values ranging from −83.7‰ to −12.4‰ and δ¹⁸O values from −11.65‰ to −2.99‰. In contrast, groundwater samples exhibit a considerably narrower isotopic range, with δ¹⁸O values between −10.98‰ and −10.1‰ and δ²H values between −73.3‰ and −68.1‰. Surface water samples show δ¹⁸O values ranging from −10.7‰ to −9.11‰ and δ²H values from −70.6‰ to −61.6‰. The results of the study show that the waters in the Vardar River basin are predominantly of meteoric origin, with their isotopic composition being strongly influenced by climatic factors and altitude, varying from approximately 1400 m and 2000 m a.s.l. The study confirms that precipitation is the primary source of both surface and groundwater. Evaporation is the dominant process that modifies isotopic signatures during rainfall, surface runoff and groundwater recharge. Due to good fit and nearly parallel meteoric lines observed in the three different locations, preliminary LMWLs and RMWL were estimated. A similar isotopic composition of surface water (SW) and groundwater (GW) in some locations indicates the presence of a direct and active hydrological connection between these water bodies, which need to be investigated in more detail in future research. However, one of the groundwater sampling locations suggest more depleted isotopic composition, which is probably related to different recharge altitudes, but also possibly very interesting relationship between Vardar River, alluvial aquifers and karst aquifer in the Žeden massif. Full article

Geothermal energy is a low-carbon baseload renewable energy that plays a key role in global energy transition. Jinlun of Taitung is a region with high potential for geothermal energy. However, sustainable resource utilization requires a comprehensive understanding of fluid sources, recharge mechanisms, and circulation systems. This study integrated δ¹⁸O, δD, ⁸⁷Sr/⁸⁶Sr and elemental geochemistry to clarify the underlying hydrogeochemical mechanism and develop an underground fluid circulation model for Jinlun. The water compositions indicate that water–rock interactions are the dominant control on fluid chemistry. Hydrogen and oxygen isotope analysis revealed a geothermal water recharge elevation of 1321–1478 m, slightly higher than that of hot spring water (951–1459 m). The natural recharge amount of a corresponding area was approximately 13.57 × 10⁶ t/yr. A strontium isotope mixing model indicated that the fluids were affected by three end members of deep geothermal water, shallow groundwater, and seawater. Shallow groundwater had a contribution rate of 92–98% to noncoastal hot spring water and up to 81% to geothermal water. The coastal hot spring was most affected by seawater at 48%. Rainwater infiltrated into E2 to form shallow groundwater. Some of the infiltrated water reached a deep circulation into the M3 layer and formed deep-source thermal water. Overall, this study establishes a hydrogeochemical model for Jinlun and provides scientific foundation for geothermal well design and sustainable resource management. Full article

The development of sustainable and climate-resilient food systems increasingly relies on robust analytical methodologies capable of integrating environmental, biochemical, and management-related signals. In this study, a multi-isotope framework based on δ²H, δ¹⁸O, δ¹³C, and δ¹⁵N was applied to assess its capacity to discriminate between contrasting raspberry production systems and to provide chemically grounded indicators of agroecosystem functioning. Raspberry fruits (Rubus idaeus L.; cultivars Opal and Delniwa) were collected during the 2024–2025 growing seasons from two distinct systems in Romania: an organic open-field system and a rainfed agroforestry system. Stable isotope ratio analysis revealed system-dependent isotopic patterns, with the strongest differentiation observed for δ¹⁵N. Nitrogen isotope composition (δ¹⁵N) provided the strongest discrimination, with enriched values in organic fruits (2.73–9.77‰) and depleted values in agroforestry fruits (−3.01 to 0.62‰), reflecting differences in nitrogen sources and cycling pathways. Hydrogen and oxygen isotopes (δ²H: −60.46 to −4.62‰; δ¹⁸O: −6.19 to 10.41‰) were consistent with hydroclimatic variability and evaporative fractionation processes associated with soil–plant–atmosphere interactions. Carbon isotopes (δ¹³C: −28.14 to −22.62‰) provided complementary insights into plant water-use conditions. Multivariate statistical analysis supported the separation between production systems, while short-term fertilisation effects were secondary to system-level controls. The results suggest that raspberry fruits preserve an integrated isotopic fingerprint of production environment and management practices. From an analytical chemistry perspective, this work highlights the relevance of multi-isotope approaches as transferable tools for food authentication, traceability, and sustainability assessment, contributing to the broader application of stable isotope techniques across complex biological systems. Full article

The North China Craton hosts abundant skarn iron resources, yet the regional large-scale mineralization mechanism remains incompletely understood. The Litun deposit is a newly discovered skarn iron deposit in the North China Craton. Integrated field geological investigations, petrographic observations, fluid inclusion microthermometry and stable isotope geochemistry are applied to constrain evaporite contributions to metallogenic processes. Four mineralization stages are identified: skarn, oxide, sulfide, and carbonate. Early skarn-stage fluids are iron-rich magmatic hydrothermal fluids with high temperatures (498 to >550 °C), high salinities (18.6 to 59.4 wt% NaCl eqv.), and magmatic δ¹⁸O values of 8.3 to 10.8‰. Subsequent oxide to late carbonate stages record continuous infiltration of meteoric water, supported by H–O isotopic trends of rising meteoric water proportions. Pyrite from the magnetite ores has δ³⁴S_V-CDT values between 12.0 and 15.0‰, significantly higher than those of pyrite in the Litun diorite (−0.8 to 1.1‰), indicating the contributions of sulfur from evaporites (δ³⁴S_V-CDT 26.9 to 28.6‰) in the mineralization process. Moreover, vein pyrite formed in later stages displays even higher δ³⁴S values (17.3 to 20.9‰), demonstrating progressive enrichment of evaporite-derived sulfur as hydrothermal activity evolves. Synchronous rises in meteoric water fraction and evaporite sulfur proportion indicate evaporites are delivered into the ore-forming system via meteoric water mixing. The mixing of meteoric water containing dissolved evaporites and iron-rich magmatic-hydrothermal fluids may be the major mechanism of magnetite precipitation in the Litun deposit. Full article

Phosphorites are a vital source of phosphorus for agricultural and industrial applications and are increasingly recognized for their potential as secondary repositories of critical raw materials (CRMs) such as rare earth elements plus yttrium (REYs). This study investigates deep-sea phosphorites from the Galicia Bank, Madeira, and Canary Seamounts, in the NE Atlantic Ocean, which are spatially associated with ferromanganese (Fe-Mn) mineralization. Through integrated petrographic, geochemical, and in situ isotopic analyses (O and Sr), we assess the timing, processes, and paleoenvironmental conditions of phosphogenesis and its implications for CRM enrichment. Rare earth element patterns in apatite reflect a predominant seawater-derived signature with variable Ce anomalies. Nevertheless, variable Y/Ho ratios point to evolving fluid sources including a hydrogenous component (directly derived from seawater), modified porewaters and, locally, volcanic or possibly hydrothermal inputs. Oxygen and strontium isotope compositions constrain phosphogenesis to several episodes ranging from the Upper Cretaceous to the Middle Miocene, with distinct isotopic shifts identifying both primary formation and later overprinting processes mostly linked to Fe-Mn oxyhydroxide growth or volcanic–hydrothermal activity. These findings highlight the dynamic and multiphase nature of phosphorite formation in deep-marine settings. The integration of high-resolution geochemical and isotopic tools proves essential for reconstructing genetic histories, defining metallogenic context and evaluating CRM prospectivity in complex submarine systems. Full article

The Shizui Cu–Pb–Zn deposit is located in central Jilin Province. It sits at the tectonic junction between the eastern Xing’an–Mongolia Orogenic Belt (XMOB) and the northeastern North China Craton (NCC). This is the first discovered Paleozoic Cu-polymetallic deposit in the region. Our study combines detailed geological investigation with systematic fluid inclusion analysis. We analyzed samples from four distinct paragenetic stages. Analytical methods include microthermometry, laser Raman spectroscopy, and hydrogen-oxygen isotope analysis. These data constrain the source, evolution, and precipitation mechanisms of the ore-forming fluids. The results delineate a clear evolutionary path: the ore-forming fluid originated as a high-temperature (346–437 °C), high-salinity (up to 51.68 wt.% NaCl equiv.) NaCl–H₂O–CO₂ system during the early quartz-sulfide stage (Stage I, Quartz ± Arsenopyrite ± Pyrite Stage), as evidenced by the coeval presence of high-salinity S-type and CO₂-rich C-type inclusions, indicating fluid immiscibility. The fluid then evolved into a boiling, medium temperature to high temperature (262–355 °C), high-salinity NaCl–H₂O system during the later part of early quartz-sulfide stage (Stage II, Quartz-Cu Polymetallic Sulfide Stage), a transition marked by the common coexistence of liquid-rich (L-type) and vapor-rich (V-type) inclusions with similar homogenization temperatures. This phase separation (boiling) served as the primary trigger for the massive deposition of chalcopyrite, arsenopyrite, and pyrite. Subsequently, the system cooled and diluted, transforming into a medium- to low-temperature (182–275 °C), low-salinity, partially homogeneous NaCl–H₂O system in the late quartz-sulfide stage (Stage III, Quartz-Pb-Zn Polymetallic Sulfide Stage). Finally, in the quartz-carbonate stage (Stage IV, Quartz-Carbonate Stage), the fluid temperature further decreased, resulting in a low-temperature (128–211 °C), low-salinity, homogeneous NaCl–H₂O system. Hydrogen-oxygen isotope data show that the calculated δ¹⁸O_H2O values decreased from +6.6‰ to +6.7‰ in Stage I to +3.4‰ to +3.9‰ in Stage II, and further to −0.4‰ in Stage III, while the δD values shifted from −91.6‰ to −90.6‰, to −94.4‰ to −94.2‰, and finally to −95.7‰. This trend indicates that the initial magmatic fluid progressively mixed with meteoric water. The geological characteristics, spatial association with Hercynian biotite monzogranite, developed skarn alteration, and the documented fluid evolution trajectory collectively affirm that the Shizui deposit is a typical skarn-type system. The deposit shares significant similarities in mineralization conditions, age, and tectonic setting with the skarn-type Tianbaoshan Pb–Zn–Cu–Mo deposits in the western segment of the XarMoron–Changchun Metallogenic Belt (XCMB). This correlation strongly suggests that the Paleozoic XCMB extends eastward and holds considerable potential for the discovery of late Paleozoic skarn-type Cu-polymetallic deposits in its eastern part. Full article

In recent years, the distribution of potassium salt resources in the Central Asia–Tarim Basin salt lake chain has shown an asymmetric pattern, and exploration efforts in the northwestern Tarim Basin have not seen significant progress. This study focuses on the central Bachu Uplift within the Central Asia–Tarim Basin salt lake chain. The characteristics of subsurface brines and indicators of potash formation are investigated. By examining various potassium exploration indices, such as the potassium–chlorine coefficient and magnesium–chlorine coefficient, along with comprehensive analysis of hydrogen–oxygen, sulfur, and strontium isotopes, this research serves to evaluate the potential for potash formation in the central Bachu Uplift. Analysis shows a brine salinity of 12.69–88.46 g/L and a potassium concentration of 0.07–0.65 g/L. The hydrochemical coefficients indicate a high nNa/nCl value, with low K × 10³/Cl values. All brine samples plot within the halite phase field of the 25 °C Na⁺,K⁺,Mg²⁺//C1⁻-H₂O Quaternary metastable phase diagram, clustering towards the Na-rich end. This indicates that the brine likely originated from halite dissolution. In the Na⁺,K⁺,Mg²⁺//C1⁻,SO₄²⁻-H₂O Quinary metastable phase diagram, the majority of samples project within the mirabilite phase field, trending toward the sylvite field. This suggests that the shallow subsurface brine may still be in the early to middle stages of sylvite deposition. Hydrogen and oxygen isotopes indicate that the brine samples were influenced by water–rock interaction and strong evaporative concentration; strontium isotopes reveal their marine–continental transitional characteristics; and sulfur isotopes suggest that the sulfur in the samples was derived from the weathering of Meso-Cenozoic gypsum in the western Tarim Basin. This integrated evidence implies that the brines in the central Bachu Uplift contain a deep-seated potassium anomaly, with fault zones likely conveying information about deep potash resources. This provides preliminary evidence for potassium exploration in the area and holds significant indicative value for identifying key prospective targets. Full article

High-fluoride (F⁻) groundwater is a widespread environmental problem that poses significant risks to human health in many regions worldwide. Understanding the origin, circulation, and evolution of fluoride-rich groundwater is therefore essential for effective groundwater management and mitigation strategies. In recent years, stable isotope techniques have helped to address key gaps in understanding the hydrogeochemical processes governing F⁻ enrichment, particularly regarding the source identification and water-rock interaction mechanisms that remain poorly constrained. This study reviews the applications of hydrogen–oxygen, strontium–calcium, and lithium–boron isotopes in research on high-F⁻ groundwater systems. Hydrogen and oxygen isotopes (δ²H and δ¹⁸O) are widely used to identify groundwater recharge sources, mixing processes, and evaporative effects, thereby providing key constraints on the origin of fluoride-rich groundwater. Strontium and calcium isotopes (⁸⁷Sr/⁸⁶Sr and δ^44/40Ca) serve as effective tracers of water-rock interactions and associated hydrogeochemical processes, including mineral weathering and dissolution, cation exchange, and secondary mineral precipitation, which play critical roles in fluoride mobilization and enrichment. In addition, lithium, and boron isotopes (δ⁷Li and δ¹¹B) provide valuable insights into the influence of geothermal fluids and deep hydrothermal processes on fluoride accumulation in groundwater systems. Overall, the integrated application of these stable isotope systems offers a robust framework for elucidating the formation mechanisms and evolutionary pathways of high-F⁻ groundwater. Moving beyond qualitative source identification, future research should prioritize the development of Bayesian isotope mixing models that explicitly quantify uncertainty in fluoride source apportionment and utilize sensitivity analysis to test competing hydrogeochemical mechanisms. Full article

The Danba–Dadu River gold belt on the western Yangtze Craton margin is a major gold province in China. The Dulanggou gold deposit is a large quartz-vein-type deposit recently discovered in this belt. Ore bodies are fault-controlled veins hosted in high-grade metamorphic rocks of the Devonian Weiguan Formation. Mineralization includes three stages: early (quartz–minor sulfide), main (quartz–abundant sulfide–native gold–Te–Bi minerals), and late (quartz–minor sulfide–calcite). Fluid inclusion studies show the following. Early-stage inclusions are mainly CO₂–H₂O-type (homogenization temperature 307–388 °C, salinity 0.4–7.1 wt.% NaCl eqv.) with minor NaCl–H₂O-type. Main-stage inclusions are dominated by CO₂–H₂O and NaCl–H₂O types, with minor pure CO₂ inclusions (homogenization temperature 207–307 °C, salinity 0.2–11.2 wt.% NaCl eqv.). Late-stage inclusions are mainly NaCl–H₂O-type (168–223 °C, 4.6–10.1 wt.% NaCl eqv.). Laser Raman analysis detects CH₄ in the fluid. The ore-forming fluid is a reducing, medium–low temperature, low-salinity H₂O–CO₂–NaCl–CH₄ system. Thermodynamic calculations of CO₂–H₂O inclusions yield total densities of 0.94–1.03 g/cm³ and total homogenization pressures of 170–276 MPa for the early stage, and slightly lower densities (0.94–1.01 g/cm³) with pressures of 170–246 MPa for the main stage, indicating a progressive pressure decrease during fluid evolution. Hydrogen and oxygen isotopes (early stage: δD −96.4‰ to −78.9‰, δ¹⁸OH₂O 6.1‰ to 6.5‰; main stage: δD −104.3‰ to −75.1‰, δ¹⁸OH₂O 5.3‰ to 7.1‰) indicate that the ore-forming fluid was mainly derived from primary magmatic water. Immiscible CO₂–H₂O and NaCl–H₂O inclusion assemblages in the main stage suggest that fluid immiscibility was the key mechanism for gold precipitation. The Dulanggou deposit resembles classic orogenic gold deposits in host rocks, ore-controlling structures, mineral assemblages, and low-salinity CO₂-rich fluids. However, its H–O isotopes and thermodynamic data point to a magmatic water source, distinct from the metamorphic water source of typical orogenic gold deposits. This highlights the diversity of fluid sources in orogenic gold systems along the western Yangtze Craton margin. Full article

Neutron-capture products, such as molybdenum (Mo) isotopes, are an important tool that cosmochemists use to constrain the stellar precursors of the Solar System and, potentially, the origin of life on Earth. Using high-precision Mo isotope data from meteorites and terrestrial samples, studies have attempted to reconstruct Earth’s formation by linking its composition to material sourced from various heliocentric distances. Debate, however, persists about the nature of Earth’s late-stage building blocks that accreted around the time the Moon formed and whether they delivered life-essential elements (i.e., carbon, hydrogen, nitrogen, oxygen, phosphorus, and sulfur; CHNOPS), which are presumed to be more prevalent in the outer Solar System. Initially, it was proposed that the Moon-forming event involved the addition of material from both the inner and outer Solar System, thereby providing a mechanism for the delivery of a significant portion of life-bearing elements late in Earth’s formation. Recent advancements in analytical chemistry and their application to a wider range of samples than previously studied, however, led to a revised constraint: the Moon-forming event was dominated by inner Solar System material that was less enriched in CHNOPS, thereby relaxing the requirement for the delivery of a consequential amount of life-bearing elements late in Earth’s formation. A review of analytical approaches and findings is presented here to highlight the utility of neutron-capture products in constraining the origin of life on Earth. Full article

To address the challenges of identifying mine water inrush sources and the low efficiency of risk control under complex karst hydrogeological conditions in the Beiya Gold Mine, Yunnan, this study proposes an intelligent identification model integrating nonlinear feature extraction and intelligent parameter optimization. Utilizing 42 sets of measured water samples (comprising karst springs, surface water, and solution caves), a coupling identification model was constructed based on 11-dimensional features including hydrochemical indices and hydrogen–oxygen isotopes. The model employs Kernel Principal Component Analysis (KPCA) to extract discriminative low-dimensional features from nonlinear data, while the critical parameters of the Support Vector Machine (SVM) are optimized via an Improved Sparrow Search Algorithm (ISSA) to enhance generalization performance. The results demonstrate that the following: (1) the proposed model achieves an identification accuracy of 91.7% on the independent test set, significantly outperforming benchmark models such as RF and standard SVM; (2) three sets of comparative experiments indicate that the fusion of multi-source features yields superior identification performance compared to single-source inputs; and (3) SHAP (shapley additive explanation) interpretability analysis reveals that HCO₃⁻, Mg²⁺, Ca²⁺, and F⁻ are the core discriminative factors, with their contribution patterns aligning closely with the hydrogeochemical evolution mechanisms of the mining area. This model achieves a synergy between high-precision identification and mechanical interpretability, providing reliable technical support for water disaster prevention in karst mining areas. Full article

The Sichuan–Yunnan–Guizhou (SYG) metallogenic belt hosts numerous carbonate-hosted Pb-Zn deposits, yet the genesis of lead-dominated deposits remains poorly understood. This study investigates the Wuyi Pb deposit, a representative lead-dominated deposit in the SYG belt, through an integrated approach including field geology, fluid inclusion microthermometry, and C-H-O-S-Pb isotope geochemistry. The ore bodies occur as stratoid and lenticular lenses within the dolomitic limestone of the Ordovician Dajing Formation, controlled by both lithology and the Wuyi composite fold structure. Mineralization is divided into two stages: (I) pyrite–sphalerite–dolomite–calcite, and (II) galena–calcite–quartz–anhydrite. Fluid inclusion studies reveal that the ore-forming fluids are of the NaCl-H₂O system, characterized by moderate-low temperatures (Stage II, average 201 °C) and moderate-low salinities (Stage II, average 5.35 wt% NaCl eq.). Hydrogen and oxygen isotopes (δD = −100.97 to −76.33‰; δ¹⁸O_fluid = 7.09 to 12.10‰) indicate that the ore-forming fluids were predominantly meteoric in origin. Carbon isotopes (δ¹³C = −4.45 to 0.75‰) suggest that carbon was derived mainly from dissolution of the host carbonate rocks. Sulfur isotopes show a significant shift from Stage I (δ³⁴S = −12.40 to −3.00‰) to Stage II (δ³⁴S = −8.20 to −0.10‰ for sulfides; 25.00–29.40‰ for sulfates), indicating a transition from bacterial sulfate reduction (BSR) to thermochemical sulfate reduction (TSR) as the dominant sulfur reduction mechanism, with sulfur derived from Ordovician seawater sulfate. Lead isotopes (²⁰⁶Pb/²⁰⁴Pb = 18.10–25.37, ²⁰⁷Pb/²⁰⁴Pb = 15.50–21.72, ²⁰⁸Pb/²⁰⁴Pb = 38.29–53.90; μ = 9.30–21.05) demonstrate that metals were sourced predominantly from the Proterozoic basement rocks (Kunyang and Huili groups). Integration of geological, geochemical, and isotopic evidence indicates that the Wuyi Pb deposit formed during the Indosinian post-collisional intracontinental orogeny (ca. 230–200 Ma), when topography-driven meteoric water circulation extracted metals from the Precambrian basement and sulfur from Ordovician strata. Metal precipitation under the reduced sulfur model is caused by decreases in temperature and pressure and the water–rock reaction. This study establishes the Wuyi deposit as an MVT Pb deposit and provides a genetic model for lead-dominated mineralization in the SYG belt. Full article

Against the background of a warming and humidifying climate on the Qinghai–Tibet Plateau, increasing attention has been paid to the sustainability of water resources and ecosystems in the Qinghai Lake Basin. Investigating the characteristics of precipitation stable isotopes and moisture sources provides critical insights into the driving mechanisms of the regional hydrological cycle. In this study, precipitation samples collected at the Qinghai Lake Wetland Ecosystem National Observation and Research Station from June 2023 to October 2024 were analyzed for hydrogen (δ²H) and oxygen (δ¹⁸O) stable isotopes. The temporal variations of δ²H, δ¹⁸O, and deuterium excess (d-excess) were characterized, and their relationships with air temperature and precipitation amount were examined. In addition, a backward trajectory model was employed to identify the moisture sources of precipitation during the observation period. The results indicate that: (1) precipitation stable isotopes and d-excess exhibit pronounced seasonal variability, characterized by enrichment in summer and depletion in spring and autumn; (2) the Local Meteoric Water Line (LMWL) for the basin is defined as δ²H = 8.15δ¹⁸O + 38.71 (R² = 0.93), with both slope and intercept exceeding those of the Global Meteoric Water Line (GMWL); (3) precipitation isotopes show a discernible temperature effect but are jointly controlled by multiple moisture sources and meteorological factors; and (4) backward trajectory analysis combined with d-excess values reveals that precipitation moisture is primarily derived from westerly transport, while locally recycled moisture and continental air masses also exert significant influences. Overall, these findings reveal the multi-source driving mechanisms of the regional hydrological cycle and provide critical scientific support for understanding hydrological processes in alpine inland basins and their responses to future climate change, thereby contributing to the sustainable management of regional water resources. 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