Isotope Analysis Research Articles

Evolutionary ecology of denitrifying methanotrophic NC10 bacteria in the deep-sea biosphere.

The NC10 phylum links anaerobic methane oxidation to nitrite denitrification through a unique O2-producing intra-aerobic methanotrophic pathway. Although numerous amplicon-based studies revealed the distribution of this phylum, comprehensive genomic insights and niche characterization in deep-sea environments were still largely unknown. In this study, we extensively surveyed the NC10 bacteria across diverse deep-sea environments, including waters, sediments, cold seeps, biofilms, rocky substrates, and subseafloor aquifers. We then reconstructed and analysed 38 metagenome-assembled genomes (MAGs), and revealed the extensive distribution of NC10 bacteria and their intense selective pressure in these harsh environments. Isotopic analyses combined with gene expression profiling confirmed that active nitrite-dependent anaerobic methane oxidation (n-DAMO) occurs within deep-sea sediments. In addition, the identification of the Wood-Ljungdahl (WL) and 3-hydroxypropionate/4-hydroxybutyrat (3HB/4HP) pathways in these MAGs suggests their capability for carbon fixation as chemoautotrophs in these deep-sea environments. Indeed, we found that for their survival in the oligotrophic deep-sea biosphere, NC10 bacteria encode two branches of the WL pathway, utilizing acetyl-CoA from the carbonyl branch for citric acid cycle-based energy production and methane from the methyl branch for n-DAMO. The observed low ratios of non-synonymous substitutions to synonymous substitutions (pN/pS) in n-DAMO-related genes across these habitats suggest a pronounced purifying selection that is critical for the survival of NC10 bacteria in oligotrophic deep-sea environments. These findings not only advance our understanding of the evolutionary adaptations of NC10 bacteria but also underscore the intricate coupling between the carbon and nitrogen cycles within deep-sea ecosystems, driven by this bacterial phylum.

Quartz Crystal Microbalance as a Holistic Detector for Quantifying Complex Organic Matrices during Liquid Chromatography: 2. Compound-Specific Isotope Analysis.

In carbon-compound-specific isotope analysis (carbon CSIA) of environmental micropollutants, purification of samples is often required to guarantee accurate measurements of a target compound. A companion paper has brought forward an innovative approach to couple a quartz crystal microbalance (QCM) with high-performance liquid chromatography (HPLC) for the online quantification of matrices during a gradient HPLC purification. This work investigates the benefit for isotope analysis of polar micropollutants typically present in environmental samples. Here, we studied the impact of the natural organic matter (NOM) on the isotopic integrity of model analytes and the suitability of the NOM-to-analyte ratio as a proxy for the sample purity. We further investigated limitations and enhancement of HPLC purification using QCM on C18 and C8 phases for single and multiple targets. Strong isotopic shifts of up to 3.3% toward the isotopic signature of NOM were observed for samples with an NOM-to-analyte ratio ≥10. Thanks to QCM, optimization of matrix removal of up to 99.8% of NOM was possible for late-eluting compounds. The efficiency of HPLC purification deteriorated when aiming for simultaneous purification of two or three compounds, leading to up to 2.5% less NOM removal. Our results suggest that one optimized HPLC purification can be achieved through systematic screening of 3 to 5 different gradients, thereby leading to a shift of the boundaries of accurate carbon CSIA by up to 2 orders of magnitude toward lower micropollutant concentrations.

Isotopic niches reveal the trophic structure of the cetacean community in the oceanic waters around the Azores

IntroductionThe oceanic waters around the Azores host a high diversity of cetaceans, with 28 species of toothed and baleen whales present year-round or seasonally. This high cetacean biodiversity likely plays an important role in the structure, functioning and productivity of the ecosystem, and may increase trophic redundancy, thus contributing to food web resilience to disturbances.MethodsHere we used stable isotope (δ13C and δ15N) analysis to characterize trophic niches, assess niche overlap, describe the trophic structure and discuss potential redundancy in the cetacean community. Using 407 samples from 12 species, we estimated Standard Ellipse Areas and overlaps between species and used a hierarchical clustering analysis to identify trophic guilds.Results and discussionδ13C and δ15N values ranged from -20.53 to -15.46‰ and from 7.78 to 14.41‰ respectively, suggesting the use of diverse habitats and resources among cetacean species. Clustering analysis revealed that species were grouped into four trophic guilds, segregated mainly by trophic position (TP): a low-TP guild with three zooplanktivore baleen whales, a mid-TP guild with micronektivores, a high-TP guild with micronekton and nekton consumers, and a cluster with only Pseudorca crassidens. There was significant isotopic niche overlap between one pair of species within each guild, indicating some potential for trophic redundancy in the community. Yet, these pairs also showed some form of spatial or temporal partitioning, suggesting that mechanisms promoting species coexistence could play a key role in structuring the cetacean community in the region and in its ecological role.

Ecological impact of a generalist invader in the aquatic food web is mediated by environmental context

Abstract Freshwater ecosystems are threatened by the introduction of invasive species. Generalist invaders often compete with native species for shared resources, resulting in possible native species niche displacement. However, environmental heterogeneity may modulate the level of individual specialisation in invasive species, altering the outcome of interspecific competition between invasive and native species. The objectives of our study were to (1) evaluate the environmental context of dietary specialisation and trophic position of an invasive species according to the Environmental Matching Hypothesis (EMH), and (2) consider how the environmental context of invasive species dietary resource use may influence the dietary niche of native species competing for similar resources. Resource use, trophic position and dietary niche were determined using gut content and stable isotope analyses for the invasive round goby (Negobius melanostomus) and the native yellow perch (Perca flavescens), along environmental gradients in an invaded fluvial ecosystem. Our results were in support of EMH for the invader diet and resource specialisation, but not trophic position. Under environmental conditions of high water‐conductivity, round gobies were generalists feeding mostly on pelagic prey. Under more challenging environmental conditions of low water‐conductivity, the invader specialised on preferred high‐quality benthic prey. The ecological impact of the round goby was greatest at low water‐conductivity sites where the invader was a benthic specialist; there was a greater relative dietary niche overlap between the invader and the native species. Our study uniquely illustrates how invasive species’ resource specialisation can be modulated by spatial environmental heterogeneity within ecosystems, and how this can subsequently alter the ecological impact of the invader on native species in aquatic food webs.

Determining sugar and molasses origin by non‐exchangeable hydrogen stable isotope of ethanol and carbon isotope ratio mass spectrometry

AbstractThis study explores the differentiation of sugar and molasses produced from sugar beet and cane, which are susceptible to fraudulent labeling due to differing production costs. The research aimed to authenticate these products by botanical origin using novel analytical techniques. Utilizing ethanol isotopic measurement–isotope ratio mass spectrometry (IRMS) for non‐exchangeable hydrogen stable isotopes alongside carbon stable isotopes analysis through elemental analyzer–IRMS, the study accurately identified the origin of various sugar and molasses samples, pinpointed mislabeled goods, and determined the source of products with previously unknown provenance. These methods were also effective in revealing sugar and molasses adulteration and quantifying the extent of such fraud. The combined isotope analyses demonstrated their potential as robust tools for combating misrepresentation and adulteration in the sugar industry.

Liquid Chromatography Coupled to Isotope Ratio Mass Spectrometry Expanded to Include Organic Mobile Phases.

Current commercially available liquid chromatography coupled to isotope ratio mass spectrometry systems (LC-IRMS) oxidize all eluent and thus can only operate with all-aqueous mobile phases, limiting their application to a small subset of analytes and mixtures that can be separated without organic solvents. We report a novel rotating-catalytic disc desolvation device with subsequent laser-activated photocatalytic analyte combustion to create CO2 for high precision carbon isotope ratio measurements compatible with both aqueous and organic liquid mobile phases. Sucrose, glucose, androsterone, or androsterone acetate in 20% and 50% H2O-CH3OH solutions were introduced by flow injection to the interface to IRMS for sugars and steroids, respectively. Sucrose δ13CVPDB linearity was excellent over 1-10 μg (33-655 nmol C) injections, using IRMS compatible He/1%O2 oxidation gas. The limit of precise isotope analysis (LOIA) of δ13CVPDB was 1 μg (35 nmol C) for sucrose and 10 μg (655 nmol C) for androsterone with average precisions of SD(δ13C) ± 0.8‰. Calibration was performed with and bracketed the δ13CVPDB isotope ratio range using androsterone-acetate and glucose. With further development to improve sensitivity and application to chromatography, the prototype proof-of-principle LC-IRMS shows promise to resolve a major drawback in current LC-IRMS systems and may open LC-IRMS to many more compounds than currently possible.

Seasonal dynamic of the benthic food web in subtidal sandbanks

Submarine sandbanks are prevalent worldwide but, paradoxically, these ecosystems and their dynamics remain largely unknown. As submarine sandbanks are targeted by a large variety of human activities, there is an urgent need for sound scientific knowledge for environmental impact assessments (EIAs) and the appropriate management of biodiversity in these areas. To our knowledge, the present study is the first to investigate the seasonal dynamics of the benthic food web in sandbank areas. We performed a stable isotope analysis in the French part of the southern North Sea. This area is typified by numerous sandbanks and by massive phytoplankton blooms in spring. We found a very simple food web structure that is heavily dependent on organic matter particles in seawater. Primary consumers, i.e. deposit feeders and, to a lesser extent, suspension feeders, dominate the benthic biomass. Small predator-scavengers such as annelids, shrimps and crabs prey upon them. Fish predators such as Echiichthys vipera represent a very restricted proportion of the biomass. We observed that the general structure of the food web is relatively well preserved over seasons. We thus propose that the functioning of the ecosystem is resilient to natural disruptions—such as dune migrations—and, probably, to anthropogenic disturbances.

Drought Stress Might Induce Sexual Spatial Segregation in Dioecious Populus euphratica—Insights from Long-Term Water Use Efficiency and Growth Rates

P. euphratica stands as the pioneering and dominant tree within desert riparian forests in arid and semi-arid regions. The aim of our work was to reveal why dioecious P. euphratica in natural desert riparian forests in the lower Tarim River exhibits sexual spatial distribution differences combined with field investigation, tree ring techniques, isotope analysis techniques, and statistical analyses. The results showed that P. euphratica was a male-biased population, with the operational sex ratio (OSR) exhibiting spatial distribution differences to variations in drought stress resulting from groundwater depth change. The highest OSR was observed under mild drought stress (groundwater depth of 6–7 m), and it was reduced under non-drought stress (groundwater depth below 6 m) or severe drought stress (groundwater depth exceeding 7 m). As drought stress escalated, the degradation and aging of the P. euphratica forest became more pronounced. Males exhibited significantly higher growth rates and WUEi than females under mild drought stress. However, under severe drought stress, males’ growth rates significantly slowed down, accompanied by significantly lower WUEi than in females. This divergence determined the sexual spatial segregation of P. euphratica in the natural desert riparian forests of the lower Tarim River. Furthermore, the current ecological water conveyance project (EWCP) in the lower Tarim River was hard to fundamentally reverse the degradation and aging of the P. euphratica forest due to inadequate population regeneration. Consequently, we advocated for an optimized ecological water conveyance mode to restore, conserve, and rejuvenate natural P. euphratica forests.

Geology, fluid inclusion, 40Ar-39Ar geochronology, and isotope constraints on the ore genesis of the Ershiyizhan Cu–Au deposit, Heilongjiang Province, China

The Ershiyizhan Cu–Au deposit, located in the eastern part of the upper Heilongjiang metallogenic belt, north of the Great Xing'an Range, is composed of orebodies from the Mesozoic magmatic rocks and the Ershierzhan group. There are three metallogenic stages of this deposit, (1) Quartz-K-feldspar-polymetallic sulfide stage (stage Ⅰ), (2) quartz-polymetallic sulfide stage (stage II), and (3) quartz-calcite ± pyrite stage (stage Ⅲ). Three types of fluid inclusions (FIs) were discovered in the vein mineral assemblages, liquid-rich two-phase aqueous FIs (L-type), vapor-rich aqueous FIs (V-type), and multi-phase FIs (S-type) with daughter minerals, including S1-type inclusions homogenized through vapor disappearance and S2-type inclusions homogenized by halite dissolution. Quartz of stage I and stage II contains all of these FIs. In contrast, the L-type fluid inclusions of stage III veins are the only ones present in the calcite. The homogenization temperatures and salinities obtained from FIs in stages I, II, and III range from 330 to 563 °C, 223 to 423 °C, and 108 to 225 °C, and 0.88 to 66.18 wt%, 2.41 to 48.59 wt%, and 0.18 to 3.23 wt% NaCl equiv., respectively. δ18O and δD values obtained from stable isotope analyses of K-feldspar and quartz samples collected from stages I, II, and III range from −2.31 to 7.89 and −133.2 to −98.2, respectively. Microthermometry and H-O isotope data from FIs suggest that the ore-forming fluids of the deposit had a magmatic origin, characterized by high temperatures, low–high salinities, an H2O-NaCl fluid system and this fluid system evolved to a low temperature, low salinities fluid through the gradual combination of meteoric water from stages II to III. Trapping pressures estimated from boiling L-type, V-type, and S1-type fluid inclusions in stage Ⅰ were 100–500 bars, corresponding to a mineralization depth of 1.0 to 5.0 km, with fluid boiling and mixing likely being responsible for the precipitation of sulfides and gold. K-feldspar from an auriferous vein of stage I yielded an 40Ar/39Ar isotopic plateau age of 131.21 ± 0.52 Ma, suggesting that the mineralization of the deposit is closely associated with the Early Cretaceous quartz monzonite porphyry. The analysis of the S isotope of metal sulfides in this deposit demonstrate that the sulfur reservoir is primarily derived from a hybrid magma source consisting of both mantle-derived and crustal-derived materials. Lead radioactive isotopic analysis for metal sulfides and various wall rocks also implies the lead source is a mixed source of upper crust and mantle. Thus, S-Pb isotope studies indicate that a crust-mantle mixed source for the mineralization of the deposit, and ore-forming material may originate from both quartz monzonite porphyry and various surrounding rocks including Late Triassic-Early Jurassic monzogranite, granite, quartz syenite, and the Ershierzhan Formation. Considering the geology, geochronology, FI, and H-O-S-Pb isotopic characteristics, the Ershiyizhan Cu–Au deposit is classified as a porphyry deposit formed in an extensional environment due to the delamination of the thickened lower crust following the Mongolian-Okhotsk Ocean closure.

Unveiling Hunnic legacy: Decoding elite presence in Poland through a unique child’s burial with modified cranium

This article presents a double burial from Czulice indicating elements of the Hunnic culture. Individual I, aged 7–9, and Individual II, aged 8–9 with a skull deformation, were both genetically identified as boys. Individual II, who exhibited genetic affinity to present day Asian populations, was equipped with gold and silver items. In contrast, Individual I displayed European ancestry. The application of strontium isotope analysis shed light on the origins of the individuals. Individual I was non-local, while Individual II was identified as a local, but also falling within the range commonly associated with the Pannonian Plain. Stable isotope analysis suggested a diet consisting of inland resources. Through radiocarbon dating, this burial was determined to date back to the years 395–418 CE, making it the earliest grave of its kind discovered in Poland. The analyses have provided new insights into the nature of the relationship between the Huns and the local inhabitants.

Screening Disinfection Byproducts in Arid-Coastal Wastewater: A Workflow Using GC×GC-TOFMS, Passive Sampling, and NMF Deconvolution Algorithm

Disinfection during tertiary municipal wastewater treatment is a necessary step to control the spread of pathogens; unfortunately, it also gives rise to numerous disinfection byproducts (DBPs), only a few of which are regulated because of the analytical challenges associated with the vast number of potential DBPs. This study utilized polydimethylsiloxane (PDMS) passive samplers, comprehensive two-dimensional gas chromatography (GC×GC) coupled with time-of-flight mass spectrometry (TOFMS), and non-negative matrix factorization (NMF) spectral deconvolution for suspect screening of DBPs in treated wastewater. PDMS samplers were deployed upstream and downstream of the chlorination unit in a municipal wastewater treatment plant located in Abu Dhabi, and their extracts were analyzed using GC×GC-TOFMS. A workflow incorporating a multi-tiered, eight-filter screening process was developed, which successfully enabled the reliable isolation of 22 candidate DBPs from thousands of peaks. The NMF spectral deconvolution improved the match factor score of unknown mass spectra to the reference mass spectra available in the NIST library by 17% and facilitated the identification of seven additional DBPs. The close match of the first-dimension retention index data and the GC×GC elution patterns of DBPs, both predicted using the Abraham solvation model, with their respective experimental counterparts—with the measured data available in the NIST WebBook and the GC×GC elution patterns being those observed for the candidate peaks—significantly enhanced the accuracy of peak assignment. Isotopic pattern analysis revealed a close correspondence for 11 DBPs with clearly visible isotopologues in reference spectra, thereby further strengthening the confidence in the peak assignment of these DBPs. Brominated analogues were prevalent among the detected DBPs, possibly due to seawater intrusion. The fate, behavior, persistence, and toxicity of tentatively identified DBPs were assessed using EPI Suite™ and the CompTox Chemicals Dashboard. This revealed their significant toxicity to aquatic organisms, including developmental, mutagenic, and endocrine-disrupting effects in certain DBPs. Some DBPs also showed activity in various CompTox bioassays, implicating them in adverse molecular pathways. Additionally, 11 DBPs demonstrated high environmental persistence and resistance to biodegradation. This combined approach offers a powerful tool for future research and environmental monitoring, enabling accurate identification and assessment of DBPs and their potential risks.

Isotopic, mycotoxin, and pesticide analysis for organic authentication along the production chain of wheat-derived products

Wheat-based products are staples in diets worldwide. Organic food frauds continuously threaten consumer trust in the agri-food system. A multi-method approach was applied for organic authentication and safety assessment along the production chain of pasta and bakery products. Bulk and compound-specific (CS) stable isotope ratio mass spectrometry (IRMS) suggested the δ15Nbulk, δ15Nleucine and δ15Nproline as promising organic markers, with CS able to distinguish between pairs which bulk analysis could not. Processing significantly affected the δ15Nleucine, δ13Cproline and δ13Cleucine. Multi-mycotoxin analysis (HT-2, T-2, DON, ZEN, OTA, AFB1) showed higher contamination in conventional than organic samples, while both milling and baking/drying significantly reduced mycotoxin content. Lastly, from the analysis of 400 residues, isopyrazam was present at the highest concentration (0.12 mg/kg) in conventional wheat, exhibiting a 0.12 processing factor (PF), while tebuconazole levels remained unchanged in pasta production (90 °C) but reduced below LOQ in biscuits and crackers (180–250 °C).

Linking anatomical and histological traits of the digestive tract to resource consumption and assimilation of omnivorous tetra fishes.

This study explores the interplay between digestive tract traits, food intake, and assimilation in omnivorous tetra fishes (Psalidodon bifasciatus, P. aff. gymnodontus, and Bryconamericus ikaa) from the Iguaçu River basin, an ecologically significant region known for high endemism. We hypothesize that variations in digestive tracts across species would be associated with differences in diet, isotopic composition in fish tissues, and overall diet assimilation. To test this, we employed stereoscopic and light microscopy to characterize the gross anatomy, histomorphology, and histochemistry of fish digestive tracts. Additionally, we used stomach content and stable isotope analyses to trace fish diets. While these tetra fishes shared histological structures, disparities were noted in anatomical digestive traits and diet preferences. The smallest species, B. ikaa, with a shorter intestine, had fewer pyloric caeca and primarily consumed animal-based diets. Conversely, P. bifasciatus and P. aff. gymnodontus, with longer intestines, displayed numerous pyloric caeca and consumed a balanced mix of animal and plant items. Despite anatomical and dietary differences, all three species predominantly assimilated animal-origin food. The tetra fishes had histological variations among digestive tract segments, with the esophagus having the thickest muscular layer, gradually thinning towards the posterior intestine. The final portion of the intestine exhibited a significant expansion in the lumen perimeter, while the esophagus had the smallest lumen area. Goblet cells were most concentrated in the posterior intestine for all species. The gross anatomy of these tetra fishes aligns with their omnivorous habit, while diet assimilation was dominated by animal-origin food. These findings provide crucial insights into the structural and tissue characteristics of their digestive systems, laying the groundwork for deeper exploration into the physiological aspects of their digestive tracts and enhancing our understanding of their feeding strategies.

Lacustrine deposition in response to the middle eocene climate evolution and tectonic activities, Bohai Bay Basin, China

The lower unit of the third member of the Eocene Shahejie Formation (Es3L, 42.5 to ∼40Ma) is one of the most important petroleum exploration targets in the Bohai Bay Basin. Lacustrine deposits are widely distributed in the Es3Lunit of the Shulu Sag and display strong vertical and horizontal variations in lithofacies and geochemical characteristics. Based on core data, thin-section petrography, stable δ13C isotope analyses, and organic geochemistry data, eight lithofacies and six evolutionary lake stages are identified. Combining the results of the astronomical time scale (ATS) and the radiometric age, the correlation between the evolutionary lake stages of Es3Land the Eocene global climate curve was illustrated. Tectonic movement caused the basin to subside and resulted in shallow lake formation (Stage 1) during the cooling phase prior to the Middle Eocene Climatic Optimum (MECO); then, the lake level began to rise (Stage 2) with an increasingly warm and humid climate. Stage 3 corresponds to the peak of the MECO and was influenced by the warm and humid climate during the thermal maximum period, forming a deep, freshwater lake. This stage was followed by highly turbulent lake conditions (Stage 4), which were influenced by both the cooling climate and intensive tectonic activity. Subsequently, a stable lake (Stage 5) was formed, which was mainly controlled by the slightly warming climate since the tectonic movement was relatively stable, followed by another stage of turbulent lake conditions (Stage 6). The results show that the global mid-Eocene climate played an important role on the relative lake level changes and TOC enrichment. The MECO led to a rise in the relative sea-level and the obviously rise in relative lake-level in the Bohai Bay Basin. The evolution of the depositional settings was controlled by both global climate and tectonic activities and accounted for the deposition and distribution of lithofacies with distinctly different characteristics and origins.

Effect of Water‐Rock Ratio on the Stable Isotope Record of Fluid‐Rock‐Deformation Interactions in Detachment Shear Zone

AbstractOxygen and hydrogen stable isotope analyses of quartz and muscovite veins from the footwall of the Raft River detachment shear zone (Utah) provide insight into the hydrology and fluid‐rock interactions during ductile deformation. Samples were collected from veins containing 90%–100% quartz with orientations either at a high angle or sub‐parallel to the surrounding quartzite mylonite foliation. Stable isotope analysis was performed on 10 samples and compared with previous quartzite mylonite isotope data sets. The results indicate that the fluid present during deformation of the shear zone was meteoric in origin, with a δ2H value of approximately −100‰ and a δ18O value of approximately −13.7‰. Oxygen stable isotope O18O depletion correlates with the muscovite content of the analyzed rocks. Many of the analyzed samples in this and other studies show an apparent lack of equilibrium between the oxygen and hydrogen isotope systems, which can be explained by hydrogen and oxygen isotope exchange at varying fluid‐rock ratios. Our results suggest that the Raft River detachment shear zone had a low static fluid‐rock ratio (<0.1), yet experienced episodic influxes of fluids through semi‐brittle structures. This fluid was then expelled out into the surrounding mylonite following progressive shearing, causing further 18O‐depletion and fluid‐related embrittlement.

Development and initial evaluation of a combustion-based sample introduction system for direct isotopic analysis of mercury in solid samples via multi-collector ICP-mass spectrometry

Development and initial evaluation of a combustion-based sample introduction system for direct isotopic analysis of mercury in solid samples via multi-collector ICP-mass spectrometry

Novel extraction methods and compound-specific isotope analysis of methoxychlor in environmental water and aquifer slurry samples

Novel extraction methods and compound-specific isotope analysis of methoxychlor in environmental water and aquifer slurry samples

Gas chromatography-stable isotope ratio mass spectrometry prior solid phase microextraction and gas chromatography-tandem mass spectrometry: development and optimization of analytical methods to analyse garlic (Allium sativum L.) volatile fraction

Garlic (Allium sativum L.) is not only appreciated for its flavour and taste, but it is also recognized for various health properties. The European Commission, through the attribution of the Protected Designation of Origin (PDO) certification mark, has officially recognized some specific varieties of garlic. To protect not only the commercial value but also the reputation of this appreciated product, effective tools are therefore required. For the first time, a new compound specific isotope analysis method based on carbon stable isotopic ratio measurement of the three major volatile garlic compounds allyl alcohol (AA), diallyl disulphide (DD) and diallyl trisulphide (DT) through head-space solid phase microextraction (HS-SPME) followed by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) was developed. A within-day standard deviation (Srwithin-day) of 0.3‰, 0.4‰ and 0.2‰ for δ(13C) and a between-day standard deviation (Srbetween-day) of 0.8‰, 1.0‰ and 0.6‰ of AA, DT and DD was estimated. For the first time, the ranges of isotopic variability for the three volatile compounds of red garlic from two neighbouring Italian regions (Abruzzo and Lazio) were defined analysing 30 samples. The same dataset was also considered in analysing the percentage composition of the previously mentioned three volatile compounds through gas chromatography-tandem mass spectrometry (GC-MS/MS). The two analytical approaches were combined in this explorative study, aiming to provide potential parameters to discriminate garlic samples based on their geographical origin.

Vermilion monazite: A new archean reference material for U[sbnd]Pb and Sm[sbnd]Nd microanalysis

Monazite (Vermilion) from the ~2.7 Ga Vermilion Granitic Complex (Minnesota, USA) was investigated as a potential reference material for UPb geochronology, using electron microprobe, high-precision ID-TIMS and high-spatial resolution techniques (LA-(Q/SF/MC)-ICP-MS and SHRIMP). Vermilion monazite is relatively homogeneous in BSE images. It is characterised as a monazite-(Ce) with uniform, relatively LREE-enriched chondrite-normalised REE patterns (Eu/Eu* = 0.074–0.085). ID-TIMS UPb analyses yielded concordant to slightly (−0.6% to 1.8%) discordant isotope data with weighted mean 207Pb*/206Pb* dates of 2668.6 ± 1.8 Ma (2σ, MSWD = 1.3, n = 3) and 2666.8 ± 1.8 Ma (2σ, MSWD = 4.0, n = 4). High-spatial resolution data from SHRIMP and LA-(Q /SF/MC)-ICP-MS agree with the ID-TIMS age. Using Vermilion monazite as primary reference material, LA-SF-ICP-MS analyses reproduced the age of several other reference monazites within −1.13% to +1.64% accuracy. Nd isotopes obtained via ID-TIMS and solution MC-ICP-MS returned consistent 143Nd/144Nd ratios of 0.510694 ± 0.000040 (2σ) and 0.510726 ± 0.000014 (2σ), respectively. The LA-MC-ICP-MS 143Nd/144Nd ratios of 0.51071 ± 0.00001 (2σ) and 0.51065 ± 0.00001 (2σ) are also in agreement within uncertainties. Results of SmNd isotope analyses by LA-MC-ICP-MS from two laboratories yielded mean 147Sm/144Nd ratios of 0.0869 ± 0.0002 (2.5 %RSD, 2σ, n = 58) and 0.0835 ± 0.0001 (2.2 %RSD, 2σ, n = 50), reflecting small variations in individual fragments. The initial epsilon Nd (εNdi) varies from −0.8 ± 0.5 to 0.6 ± 0.4 (2σ). The reproducibility of our results shows that Vermilion monazite can be used as a primary reference material for UPb geochronology and is suitable as a secondary reference material for SmNd isotopic tracing. The Archean age of Vermilion monazite, the oldest available as a reference material, will facilitate the investigation of Archean crustal evolution processes and broaden the prospect of studying ancient metamorphic events by combining matrix-matched UPb geochronology and SmNd isotopic tracing.

Nano-Scale Secondary Ion Mass Spectrometry: A Paradigm Shift in Soil Science

Soils exhibit structural heterogeneity across diverse spatio-temporal scales, yielding myriad of microhabitats, highlighting the need for a nuanced understanding of the intricate interactions within the soil matrix. At the nanometer scale, the interplay among organic matter (OM), mineral particles, and microbiota intricately govern the long-term destiny of soil carbon (C), nutrient cycling, and the fate of both organic and inorganic pollutants. Notably, the sorption of soil organic matter (SOM) onto smaller clay particles and its entrapment in microaggregates further contribute to this complex dynamic. Understanding these processes depends on recognizing their scale-dependent nature, necessitating sophisticated techniques for investigation. Although various methods are employed across scales, the current set of techniques still lacks the requisite sensitivity and resolution for microscale data collection. To address this limitation, the adoption of novel microscopic and spectroscopic techniques capable of probing molecular, isotopic, and elemental patterns at the micro to nano scale becomes imperative. Among these cutting-edge methodologies, the nano-scale secondary ion mass spectrometer (NanoSIMS) emerges as a paradigm-shifting tool. Representing the latest evolution in ion microprobes, NanoSIMS seamlessly integrates high-resolution microscopy and isotopic analysis, maintaining unparalleled signal transmission and spatial resolution, reaching as fine as 50 nm. Its capabilities extend beyond conventional applications in science, as evidenced by recent breakthroughs in utilizing NanoSIMS to study biophysical interfaces in soils. This article underscores the pressing need to advance the incorporation of NanoSIMS as a pioneering instrumentation technique in soil studies. Furthering the implementation of this novel instrumentation technique in soil studies will pave avenues and aid in the advancement of future research.