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Interest in subsistence strategies practiced by the Kura-Araxes communities in Southern Caucasus and the highlands of the Near East has a long history, yet direct studies of paleodiet at the scale of the individual are few. We apply serial sampling of carbon and nitrogen isotopes in 17 teeth representing 11 comingled individuals at the Kura-Araxes early Bronze Age site Köhne Shahar (KSH) in northwestern Iran. Proteomic analyses of dental enamel show seven females and four males. Isotopic results indicate an agro-pastoral diet with little or no C4 millet. Individual isotopic biographies reveal a dietary life history that includes weaning between 1.5 and 3.7 years of age (average = 2.4 years), followed by a stable early childhood diet with little intra-individual variation through age 10 years. Isotopic shifts around 12–14 years of age suggest a change in diet that may correspond to marriage and the establishment of new household units focused more on plant foods. Gradual isotopic shifts between 14 and 20 years may represent such households developing livestock herds and increasing meat consumption. Stability in diet across this transition is consistent with village endogamy. Sex-linked differences in the age of weaning and childhood δ15N values hint at differences in learning and enculturation practices. Males and about half of females were weaned earlier but had access to greater amounts of meat, suggesting they were more involved in animal husbandry and/or production of animal products (e.g., cheese, yoghurt) outside the house. By contrast, the other half of females were weaned later in childhood, but ate significantly more plant foods, suggesting they were more involved in tending gardens and producing crafts and/or plant-based foods within the house, where they had greater access to breastmilk.

Southern hemisphere blue (Balaenoptera musculus intermedia) and fin (Balaenoptera physalus) whales are the largest predators in the Southern Ocean, with similarities in morphology and distribution. Yet, understanding of their life history and foraging is limited due to current low abundances and limited ecological data. To address these gaps, historic Antarctic blue (n = 5) and fin (n = 5) whale baleen plates, collected in 1947-1948 and recently rediscovered in the Smithsonian National Museum of Natural History, were analyzed for bulk (δ13C and δ15N) stable isotopes. Regular oscillations in isotopic ratios, interpreted as annual cycles, revealed that baleen plates contain approximately 6 years (14.35 ± 1.20 cm year-1) of life history data in blue whales and 4 years (16.52 ± 1.86 cm year-1) in fin whales. Isotopic results suggest that: (1) while in the Southern Ocean, blue and fin whales likely fed at the same trophic level but demonstrated niche differentiation; (2) fin whales appear to have had more regular annual migrations; and (3) fin whales may have migrated to ecologically distinct sub-Antarctic waters annually while some blue whales may have resided year-round in the Southern Ocean. These results reveal differences in ecological niche and life history strategies between Antarctic blue and fin whales during a time period when their populations were more abundant than today, and before major human-driven climatic changes occurred in the Southern Ocean.

Arbuscular mycorrhizal fungi (AMF) transport substantial plant carbon (C) that serves as a substrate for soil organisms, a precursor of soil organic matter (SOM), and a driver of soil microbial dynamics. Using two-chamber microcosms where an air gap isolated AMF from roots, we 13CO2-labeled Avena barbata for 6 wk and measured the C Rhizophagus intraradices transferred to SOM and hyphosphere microorganisms. NanoSIMS imaging revealed hyphae and roots had similar 13C enrichment. SOM density fractionation, 13C NMR, and IRMS showed AMF transferred 0.77 mg C g-1 of soil (increasing total C by 2% relative to non-mycorrhizal controls); 33% was found in occluded or mineral-associated pools. In the AMF hyphosphere, there was no overall change in community diversity but 36 bacterial ASVs significantly changed in relative abundance. With stable isotope probing (SIP)-enabled shotgun sequencing, we found taxa from the Solibacterales, Sphingobacteriales, Myxococcales, and Nitrososphaerales (ammonium oxidizing archaea) were highly enriched in AMF-imported 13C (> 20 atom%). Mapping sequences from 13C-SIP metagenomes to total ASVs showed at least 92 bacteria and archaea were significantly 13C-enriched. Our results illustrate the quantitative and ecological impact of hyphal C transport on the formation of potentially protective SOM pools and microbial roles in the AMF hyphosphere soil food web.

Rationale: Laser‐based analyzers are widely used in ecohydrology to analyze plant water isotopic compositions (δ18O and δ2H). The suitability of three different water extraction and isotope equilibration techniques was compared. We examined whether co‐extracted volatile organic compounds (VOCs) affect laser‐based isotope measurements and used the instrument's spectral parameters to post‐correct for interfering VOCs. Methods: Cryogenic vacuum extraction, vapor headspace equilibration in bags, and vapor equilibration in situ probes were used to extract liquid water or water vapor for laser‐based isotope analysis (cavity ring‐down spectrometry, CRDS). Isotope data were calibrated by standards for each method separately. Spectral parameters of the instrument, appropriate to identify spectral interferences with MeOH and CH4, were identified and used for post‐correction. Differences between the three methods and between the origins of the vegetables were identified by statistical tests. Results: VOCs were found in various amounts for the three different methods. They were co‐extracted or co‐equilibrated during the different extraction or equilibration methods. Correlation coefficients of isotope data and "CH4" (spectral parameter) were 0.99 or better; however, slopes for δ18O were similar on different instrument types but different for δ2H. Our correction approach improved results and inter‐comparability of the methods considerably without knowing the chemical composition of the plant sap. Conclusions: All three methods were sensitive enough to distinguish and resolve differences in natural abundance. Data quality was improved by the "CH4 correction" approach but could probably be optimized by a plant species–specific correction. Standardized tools for contaminant removal or post‐correction applications from manufacturers, in particular for vapor‐mode analysis, are still needed. [ABSTRACT FROM AUTHOR]

Rationale: The oxygen stable isotope ratio (δ18O) of the sugar‐rich fraction of fruit juice is important as a tracer of the geographical origin of raw material. This study sought to minimize the inter‐day variation of δ18O attributable to the influence of water to accurately monitor geographical origin labeling. Methods: Two drying devices (freeze dryer and vacuum oven) were compared. Then, two humidity levels (normal and low humidity) at which the samples were placed after drying were compared. The low‐humidity environment was constructed using a glove bag and pure argon gas. δ18O was measured using thermal conversion elemental analyzer/isotope ratio mass spectrometry. Improvements were made to the measurement method based on aforementioned analyses results, and the performance of the initial and improved methods was compared. Results: δ18O of juice dried in a vacuum oven was 3.30‰ lower than that of juice dried in a freeze dryer. Moreover, δ18O of juice samples exposed to normal humidity was 3.74‰ lower than that of samples exposed to low humidity. The combined inter‐day and intra‐day standard deviation was reduced from 1.20‰ in the initial method to 0.42‰ in the improved method. Conclusions: This study describes a pretreatment method for δ18O measurement in the sugar‐rich fraction of fruit juice with less inter‐day variation, and it will be useful for monitoring geographical origin labeling. [ABSTRACT FROM AUTHOR]

The eruption of Somma-Vesuvius in 79 CE buried several nearby Roman towns, killing the inhabitants and burying under pumice lapilli and ash deposits a unique set of civil and private buildings, monuments, sculptures, paintings, and mosaics that provide a rich picture of life in the empire. The eruption also preserved the forms of many of the dying as the ash compacted around their bodies. Although the soft tissue decayed, the outlines of the bodies remained and were recovered by excavators centuries later by filling the cavities with plaster. From skeletal material embedded in the casts, we generated genome-wide ancient DNA and strontium isotopic data to characterize the genetic relationships, sex, ancestry, and mobility of five individuals. We show that the individuals' sexes and family relationships do not match traditional interpretations, exemplifying how modern assumptions about gendered behaviors may not be reliable lenses through which to view data from the past. For example, an adult wearing a golden bracelet with a child on their lap—often interpreted as mother and child—is genetically an adult male biologically unrelated to the child. Similarly, a pair of individuals who were thought to have died in an embrace—often interpreted as sisters—included at least one genetic male. All Pompeiians with genome-wide data consistently derive their ancestry largely from recent immigrants from the eastern Mediterranean, as has also been seen in contemporaneous ancient genomes from the city of Rome, underscoring the cosmopolitanism of the Roman Empire in this period. • We generated genome-wide data from skeletal material in Pompeii plaster casts • The data contradict prior narratives about the victims' identities and relationships • Pompeiian individuals mainly descended from recent eastern Mediterranean immigrants Pilli et al. analyze genomic data from five 79 CE Vesuvius victims, debunking prior narratives about their identities and relationships. The study highlights the limitations of projecting modern assumptions onto ancient populations. The Pompeiians primarily descend from recent eastern Mediterranean immigrants, reflecting premodern globalization. [ABSTRACT FROM AUTHOR]

Understanding the nutritional and metabolic physiology of aquatic organisms is essential for optimizing aquaculture practices and informing ecological models. We investigated the influence of dietary composition, specifically the incorporation of multienzyme extract derived from Pleoticus muelleri waste, on the growth and metabolic processes of juvenile Cherax quadricarinatus. We investigated how these dietary changes influence dietary assimilation and tissue turnover using stable isotope δ13C and δ15N dynamics, in both the pleon muscle and hepatopancreas. Juvenile crayfish were subjected to two isocaloric diets for a 90‐day period: a control diet (diet C) and a diet supplemented with a multienzyme extract (diet E) from red shrimp waste. Despite comparable growth rates, isotopic analysis (δ13C and δ15N) of the pleon muscle and hepatopancreas revealed distinct metabolic patterns between both dietary treatments. The hepatopancreas exhibited accelerated isotopic turnover relative to muscle tissue, irrespective of diet, suggesting a more dynamic metabolic role. Diet E further accelerated turnover rates in both tissues, indicative of enhanced nutrient assimilation and utilization. Consistent isotopic disparities between the hepatopancreas and muscle tissues highlighted tissue‐specific metabolic functions, with the hepatopancreas serving as a metabolic hub. Molting‐induced shifts in isotopic patterns underscored the dynamic interplay between metabolic processes and nutrient mobilization. Isotopic equilibrium was reached earlier for δ13C than δ15N, with lower discrimination factors in the hepatopancreas. While δ13C primarily supported metabolic processes, δ15N contributed substantially to growth, especially in muscle. These findings illuminate the complex interplay of dietary composition, isotopic fractionation, and physiological regulation in C. quadricarinatus. The metabolic enhancements induced by the diet supplemented with the extract warrant further investigation to optimize nutrient utilization and growth performance in aquaculture settings. [ABSTRACT FROM AUTHOR]

The trophic organization of estuarine fish communities is poorly known. We used Stable Isotopes (δ13C and δ15N) to classify the most abundant fishes of the Atrato River Delta (Colombia) into trophic guilds. We examined trophic niches and the relationships between the abundance of the trophic guilds (catch per unit effort) and environmental variables. The zoobenthivores were the dominant trophic guild. The isotopic niche width, based on Bayesian estimate of the standard ellipse areas, was more significant for carnivores (25.3‰2) and planktivores (24.4‰2) than for omnivores (7.8‰2) and phytobenthivores (3.1‰2). The overlap combinations showed a medium probability of isotopic overlap (≈50%) between carnivores and planktivores and between carnivores and omnivores. Isotopic niche size and overlap suggested diversity in food sources and considerable niche segregation of the fish community. Mangrove area was the main factor explaining the abundance of omnivores and zoobenthivores, supporting that the causal links between mangrove habitat and local fishery production may be explained through the trophic contribution of mangroves and mangrove-related sources. The results underscore the importance of mangrove areas in the trophic organization of fish communities and can inform strategies aimed at managing the ecosystem impacts of fishing and protecting extensive mangrove areas in the southern Caribbean. [ABSTRACT FROM AUTHOR]

ABSTRACT Anisakis simplex larvae, commonly found in marine fish, cause anisakiasis in humans, resulting in gastric to gastro‐allergic symptoms. Despite known health risks, the impact of Anisakidae larvae on fish hosts is less understood. This study aimed to investigate this interaction by assessing the feeding strategy of A. simplex. Anisakis larvae were isolated from North Sea Merluccius merluccius tissues (stomach, body cavity, liver and muscle) and were analysed for carbon (δ13C) and nitrogen (δ15N) isotope values. Significant differences in δ13C values were found among host tissues, with the liver differing from muscle and stomach tissues. In contrast, no differences were noted for the associated parasites. Additionally, δ15N values indicated that the host occupied a significantly higher relative trophic position than its parasite. This suggests a lack of direct nutrient transfer from host to parasite, as the parasite would typically exhibit higher stable isotope values than the tissue they feed on. Therefore, A. simplex's stable isotope values might reflect those of its previous host (crustacean and/or small fish), providing insights into diet and movement of the paratenic M. merluccius host. Further research is needed to confirm these findings across different fish species and to explore A. simplex as a proxy for trophic ecology. [ABSTRACT FROM AUTHOR]

Ecologists have long sought general explanations for the co‐occurrence of ecologically similar taxa. Niche theory explains co‐occurrence via functional differences among taxa that reduce competition and promote resource partitioning. Alternatively, the unified neutral theory of biodiversity and biogeography suggests that co‐occurrence can be attributed to stochastic processes, and thus, presupposes that ecologically similar species that occur in sympatry are functionally analogous. We test these hypotheses using the most diverse crustacean‐sea anemone symbiosis from coral reefs in the Tropical Western Atlantic. δ13C and δ15N stable isotope analyses of six crustacean symbionts that co‐occur around the host anemone Bartholomea annulata exhibit highly differentiated isotopic niche space spanning several trophic levels. As multiple crustacean species within the symbiosis have been documented as cleaners that remove parasites from reef fishes, we extended our investigation into the broader cleaner community. Our stable isotope analyses of cleaners shows that Pederson's cleaner shrimp Ancylomenes pedersoni exhibits the highest δ15N isotopic values‐ significantly higher than all other putative cleaner species and consistent with expectations of a dedicated cleaning lifestyle. However, for other species previously described or observed to clean reef fishes, including Periclimenes yucatanicus, Stenopus hispidus and Stenorhynchus seticornis, δ15N isotopic values were substantially lower, raising questions about the degree to which these species rely on cleaning interactions to meet their nutritional requirements. Taken together, our data are consistent with the expectations of niche theory: co‐occurring symbiotic crustaceans have highly partitioned niche space with low levels of functional redundancy. [ABSTRACT FROM AUTHOR]

The plant kingdom exhibits a diversity of nutritional strategies, extending beyond complete autotrophy. In addition to full mycoheterotrophs and holoparasites, it is now recognized that a greater number of green plants than previously assumed use partly of fungal carbon. These are termed partial mycoheterotrophs or mixotrophs. Notably, some species exhibit a dependency on fungi exclusively during early ontogenetic stages, referred to as initial mycoheterotrophy. Japonolirion osense, a rare plant thriving in serpentinite soils, emerges as a potential candidate for initial mycoheterotrophy or mixotrophy. Several factors support this hypothesis, including its diminutive sizes of shoot and and seeds, the establishment of Paris-type arbuscular mycorrhizal associations, its placement within the Petrosaviales—largely composed of fully mycoheterotrophic species—and its ability to face the challenging conditions of its environment. To explore these possibilities, our study adopts a multidisciplinary approach, encompassing stable isotope abundance analyses, in vitro experiments, anatomical analyses, and comparative plastome analyses. Our study aims to (1) determine whether J. osense relies on fungal carbon during germination, indicating initial mycoheterotrophy, (2) determine if it employs a dual carbon acquisition strategy as an adult, and (3) investigate potential genomic reductions in photosynthetic capabilities. Contrary to expectations, our comprehensive findings strongly indicate that J. osense maintains complete autotrophy throughout its life cycle. This underscores the contrasting nutritional strategies evolved by species within the Petrosaviales. [ABSTRACT FROM AUTHOR]

Reliable photonuclear reaction rates in stellar conditions are essential for understanding the origin of the heavy stable neutron-deficient isotopes between 74Se and 196Hg, i.e., p -nuclei. However, many reaction rates of relevance still have to rely on the Hauser–Feshbach (HF) model due to the rarity of experimental progress. One such case is in the mass range of 160 for Dy, Er, Ho, and Tm isotopes. In this work we attempt to constrain the HF model in the TALYS package by reproducing the available experimental data on 160Dy(p, γ)161Ho and 162Er(p, γ)163Tm in the A ∼ 160 mass region, and examine the effects of level density, gamma strength function, and the optical model potential. The constrained model then allows us to calculate the reaction rates of 157,159Ho(γ, p) and 163,165Tm(γ, p) for the γ -process nucleosynthesis in a carbon-deflagration model for Type Ia supernovae. Our recommended rates differ from the JINA REACLIB by more than one order of magnitude in the temperature range 2–3 GK. This results in changes in the final abundance of p -nuclei in the A ∼ 160 mass range by −5.5% to 3% from those with JINA, which means that the uncertainty of (γ, p) reactions is not predominant for the synthesis of these nuclei. [ABSTRACT FROM AUTHOR]

The impact of freshwater sources like surface river runoff and submarine groundwater discharge (SGD) on coastal waters is currently in focus of intense debate and investigation. One of the ongoing challenges in SGD research is the characterization and quantification of the freshwater endmember contributions to the subsurface mixing zone and their influences on element balance and biogeochemical transformations. Long-term investigations of the sediment porewater composition provide characterization and understanding of the physical, hydrological and biogeochemical processes controlling the substance exchanges. In this study, we focus on the hydrochemical and stable isotope (δ2H, δ18O) compositions of sediment porewaters along the coastline of a southern Baltic Sea peatland. Coastal surface water and groundwater dynamics were monitored at two coastal sites using 5-m-long stationary lances over a 5-year period.The vertical compositional gradients were used to extrapolate to zero-salinity (ZS) components applying a binary mixing model on the salinity and water isotope composition. The results characterize a subterranean estuary (STE) with three potential mixing endmembers: two fresh groundwaters and the brackish Baltic Sea. Tritium–helium (3H–3He) porewater dating gave ages of more than about 20 years for the freshwater components. The ZS components were compared with other SGD sites along the southern Baltic Sea and North Sea and highlight the importance of local SGD studies for a proper groundwater endmember characterization as basis to understand hydrological and biogeochemical developments at the land–ocean continuum in times of current climate change. [ABSTRACT FROM AUTHOR]

Desert dust is an important source of essential metals for marine primary productivity, especially in oligotrophic systems surrounded by deserts, such as the Red Sea. However, there are very few studies on the effects of dust on reef-building corals and none on the response of corals to heat stress. We therefore supplied dust to two coral species (Stylophora pistillata and Turbinaria reniformis) kept under control conditions (26 °C) or heat stress (32 °C). Since dust releases large amounts of iron (Fe) in seawater, among other metals, the direct effect of different forms of Fe enrichment on coral photosynthesis was also tested. First, our results show that the desert dust altered the coral metallome by increasing the content of metals that are important for coral physiology (e.g. lithium (up to 5-fold), manganese (up to 4-fold in S. pistillata), iron (up to 3-fold in S. pistillata), magnesium (up to 1.3-fold), molybdenum (up to 1.5-fold in S. pistillata)). Overall, metal enrichment improved the photosynthetic performance of corals, especially under thermal stress (e.g. Pgross (up to 2-fold), Pnet (up to 10-fold), chlorophyll (up to 1.5-fold), symbionts (up to 1.6-fold)). However, Fe exposure (ferric chloride or ferric citrate) did not directly improve photosynthesis, suggesting that it is the combination of metals released by the dust, the so-called "metal cocktail effect", that has a positive impact on coral photophysiology. Dust also led to a decrease in Ni uptake (up to 1.4-fold in the symbionts), likely related to the nitrogen metabolism. Finally, we found that the isotopic signature of metals such as iron, zinc and copper is a good indicator of heat stress and dust exposure in corals. In conclusion, desert dust can increase coral resistance to bleaching by supplying corals with essential metals. [ABSTRACT FROM AUTHOR]

ABSTRACT Oxygen (δ18O) and hydrogen (δ2H) stable isotope ratios are tightly coupled in precipitation and, albeit damped, in leaf water, but are often decoupled in tree‐ring cellulose. The environmental and physiological conditions in which this decoupling occurs are not yet well understood. We investigated the relationships between δ18O and δ2H and tree‐ring width (TRW), tree crown volume, tree age and climate in silver fir and Douglas‐fir and found substantial differences between δ18O and δ2H. Overall, δ18O–δ2H correlations were weak to absent but became significantly negative under high summer vapour pressure deficit (VPD). δ18O and δ2H had positive and negative nonlinear relationships with TRW, respectively, with clear relationships at the site and tree levels for silver fir and, to a lesser extent, for Douglas‐fir. Age trends for silver fir were weakly negative in δ18O but positive in δ2H. Tree crown volume and δ18O or δ2H had no significant relationships. Most strikingly, δ18O strongly depended on spring climate (precipitation and VPD), whereas δ2H depended on summer climate (temperature and VPD) for both species. Our study shows that the δ18O–δ2H decoupling in tree‐ring cellulose in two temperate conifer species could be highlighted by their contrasting relationships to climate and tree intrinsic variables (TRW, age). [ABSTRACT FROM AUTHOR]

In addition to considering the influence of a species on other species (centrality), the identification of keystone species should also consider whether it has a unique network position (uniqueness). Clarifying the correlation between species centrality and uniqueness, or whether central species exhibit positional redundancy in food webs, can enhance the understanding of mechanisms stabilizing food webs. However, the findings from analyses utilizing different measures of uniqueness are contentious. In this study, we constructed the food web of the eutrophic Zhangze Lake (northern China) using stable isotopes to estimate the contribution of food sources to consumers. We then calculated trophic field overlap index to assess the uniqueness of species using this quantified food web information. Additionally, we analyzed how the weak interaction and the threshold value under which interactions are considered as weak influence the relationship between species uniqueness and centrality. The findings revealed that, in contrast to the traditional trophic field overlap index, the improved index identified the basal species with the strongest trophic interactions with other species and the filter‐feeding fishes with the fewest interactors as the most unique species, while the basal species were considered the least unique under the traditional index. The ranking results of the traditional index and the centrality showed a significant negative correlation, whereas the improved index displayed a positive correlation, which was caused by the comprehensive consideration of threshold and weak interaction. In addition, based on the data analysis, the suggestion was given for the selection of indices used to identify unique species, and whether central species have positional redundancy was explored. The methodology used in study provides a practical solution for the identification of the most unique species, points out and solves the problems faced in the uniqueness analysis, and advances the understanding of the mechanisms underlying food web robustness. [ABSTRACT FROM AUTHOR]

In British Columbia, Canada, unidentified skeletal human remains are often recovered by law enforcement or civilians and there is a question if they are modern and of medicolegal significance, or historical or archaeological. We used relatively fast and inexpensive carbon and nitrogen stable isotope analysis of human bone collagen from a selection of these remains (n = 48) combined with a logistic regression model to classify remains as modern, historical, or archaeological. We then confirmed our temporal classification through directly radiocarbon dating each individual and found that we could predict the temporal group with 93% accuracy. In regions where archaeological remains have dietary isotope values distinct from living people, dietary stable isotope analysis can provide a time‐, and resource‐efficient method to screen cases of unidentified human remains early in death investigation. [ABSTRACT FROM AUTHOR]

Cave pearls are spherical concentric speleothems growing radially around nuclei in shallow pools saturated with calcite. They are very rare in the Southern Levant. We present a unique assemblage of 50 cave pearls found in the Iron Age Joweizeh artificial spring tunnel in the Jerusalem Hills of Israel. Some of these deposits represent the first global evidence of formation on archaeological artefacts: pottery sherds and ancient plaster. Multi‐analyses were conducted to date and characterize the different nuclei and pearls. Charcoal samples extracted from the plaster nuclei of two pearls were 14C dated to the Hellenistic period. Two pearls were formed on sherds of Hellenistic lamps. XPS found Co colour remains, suggesting both had been imported. The Hellenistic date is also supported by archaeomagnetic dates of seven other pottery nuclei. Most Hellenistic remains are probably the outcome of a renovation campaign in the tunnel. Four pearls were sampled for stable isotopes (δ13C and δ18O). The range of δ18O values from the Joweizeh pearls is compatible with the Holocene Soreq and Jerusalem caves’ records. The δ13C differences between Joweizeh and Soreq indicate local changes in the overlying vegetation throughout history. The various lines of evidence enabled us to characterize the pearls’ formation process, reconstruct the Joweizeh spring tunnel's hydraulic environment and detect changes that occurred in its water flow regime throughout history. [ABSTRACT FROM AUTHOR]

Although rhizoctonias from Ceratobasidiaceae, Tulasnellaceae and Serendipitaceae are typical orchid mycobionts, orchid mycorrhizal fungi exhibit vast taxonomic and ecological diversity. This diversity stems from the high specificity of orchid mycorrhizal associations and the remarkable diversity of over 28,000 orchid species. The subtribe Calypsoinae is particularly notable for its diverse mycorrhizal partnerships, including rhizoctonias, ectomycorrhizal and saprotrophic non‐rhizoctonia fungi. However, the mycobionts within certain Calypsoinae lineages, such as the genus Dactylostalix, remain understudied. This study explores the physiological ecology of two photosynthetic Calypsoinae species, Dactylostalix ringens and Dactylostalix uniflora, to gain insight into potentially novel associations and their ecological implications. We analysed the mycorrhizal communities of both Dactylostalix species using high‐throughput ITS metabarcoding of root samples collected from multiple locations. Additionally, we measured the natural abundances of 13C and 15N isotopes in the leaves of the two Dactylostalix species and their co‐occurring autotrophic reference plants, as well as in fungal pelotons isolated from D. ringens, to assess the potential for partial mycoheterotrophy. Our findings revealed that D. ringens and D. uniflora form specialized mycorrhizal associations predominantly with distinct lineages of Oliveonia (Oliveoniaceae, Auriculariales), even in sympatric populations. Stable isotope analysis showed that both Dactylostalix species exhibited conflicting isotopic signals: elevated δ15N values, supporting partial mycoheterotrophy, but lower δ13C values compared to autotrophic plants, suggesting autotrophy. Peloton samples from D. ringens displayed only modest 13C enrichment relative to autotrophic references. These conflicting isotopic signals make it difficult to precisely determine whether both Dactylostalix species are autotrophic or partially mycoheterotrophic. Intriguingly, the 13C and 15N signatures of Dactylostalix species and their pelotons resemble those of many rhizoctonia‐associated orchids. This isotopic evidence implies a niche overlap with endophytic tendencies between rhizoctonias and Oliveonia, suggesting that potential endophytic traits may have facilitated the recruitment of Oliveonia as novel mycorrhizal partners. Furthermore, the mycorrhizal segregation between D. ringens and D. uniflora likely promotes their sympatric coexistence and may contribute to reproductive isolation through ecological specialization. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Background and Aims Freshwater nitrogen inputs are increasing globally, altering the structure and function of wetland ecosystems adapted to low nutrient conditions. Carnivorous wetland plants of the genus Utricularia are hypothesized to reduce their reliance on carnivory and increase their assimilation of environmental nutrients when the supply of ambient nutrients increases. Despite success in using stable isotope approaches to quantify carnivory of terrestrial carnivorous plants, quantifying carnivory of aquatic Utricularia requires improvement. Methods We developed stable isotope mixing models to quantify aquatic plant carnivory and used these models to measure dietary changes of three Utricularia species, Utricularia australis , U. gibba and U. uliginosa , in 11 wetlands across a 794-km gradient in eastern Australia. Diet was assessed using multiple models that compared variations in the natural-abundance nitrogen isotope composition (δ15N) of Utricularia spp. with that of non-carnivorous plants, and environmental and carnivorous nitrogen sources. Key Results Carnivory supplied 40–100 % of plant nitrogen. The lowest carnivory rates coincided with the highest availability of ammonium and dissolved organic carbon. Conclusions Our findings suggest that Utricularia populations may adapt to high nutrient environments by shifting away from energetically costly carnivory. This has implications for species conservation as anthropogenic impacts continue to affect global wetland ecosystems. [ABSTRACT FROM AUTHOR]

Background and Aims Clonal growth is widespread among herbaceous plants, and helps them to cope with environmental heterogeneity through resource integration via connecting clonal organs. Such integration is considered to balance heterogeneity by translocation of resources from rich to poor patches. However, such an 'equalization' strategy is only one of several possible strategies. Under certain conditions, a strategy emphasizing acropetal movement and exploration of new areas or a strategy of accumulating resources in older ramets may be preferred. The optimal strategy may be determined by environmental conditions, such as resource availability and level of light competition. We aimed to summarize possible translocation strategies in a conceptual analysis and to examine translocation in two species from different habitats. Methods Resource translocation was compared between two closely related species from different habitats with contrasting productivity. The study examined the bidirectional translocation of carbon and nitrogen in pairs of mother and daughter ramets grown under light heterogeneity (one ramet shaded) at two developmental stages using stable-isotope labelling. Key Results At the early developmental stage, both species translocated resources towards daughters and the translocation was modified by shading. Later, the species of low-productivity habitats, Fragaria viridis , translocated carbon to shaded ramets (both mother and daughter), according to the 'equalization' strategy. In contrast, the species of high-productivity habitats, Potentilla reptans , did not support shaded mother ramets. Nitrogen translocation remained mainly acropetal in both species. Conclusions The two studied species exhibited different translocation strategies, which may be linked to the habitat conditions experienced by each species. The results indicate that we need to consider different possible strategies. We emphasize the importance of bidirectional tracing in translocation studies and the need for further studies to investigate the translocation patterns in species from contrasting habitats using a comparative approach. [ABSTRACT FROM AUTHOR]

Stable isotope analysis of fish muscle tissue has been used to quantify fish migratory behavior in many systems, and these chemical tracers are especially useful for euryhaline fishes that traverse significant salinities and gradients in baseline signatures. However, the removal of muscle tissues often requires lethal sampling. Fish scales may be removed non‐lethally and offer potential alternatives to stable isotope ratios from muscle to indicate recent feeding histories. For this study, red drum Sciaenops ocellatus were collected in subtropical estuaries in the northwestern Gulf of Mexico and analyzed for stable isotope (훿13C and 훿15N) compositions of scale exteriors. Decalcification of scale samples was deemed unnecessary given the preservation of linearity and minimal offsets between paired decalcified and untreated scale samples. Stable isotope signatures of muscle tissue and scales were closely matched and indicated high degrees of residence within bays at fine spatial scales. This study also surveyed the existing body of literature comparing scale and muscle isotope values from the same individuals and found that the majority reports linear relationships with slopes close to unity, although species‐specific offsets and intercepts vary. This work expands the body of literature indicating that scales are a viable non‐lethal alternative for stable isotope assessments of dietary and habitat use histories for mobile fishes. [ABSTRACT FROM AUTHOR]

The combined use of otolith chemistry and tissue isotopes has the potential to reveal movements, habitat associations and food web interactions at a variety of spatial and temporal scales. Here, a combination of otolith Ba:Ca life‐history transects with muscle tissue δ13C and δ15N values has been used to assess habitat use and oligohaline residence in red drum Sciaenops ocellatus in subtropical estuaries in the north‐western Gulf of Mexico. Tissue isotopes were distinct among capture locations, particularly between bays with differing proximities to freshwater inflow sources. Otolith edge Ba:Ca values and tissue δ13C values were not correlated. These results indicated that fish were neither residing in nor feeding in oligohaline waters for significant periods of time within the tissue turnover window of several months prior to capture. Nonetheless, spatial differences in tissue isotope values indicated limited mixing among bays and relatively high site fidelity during estuarine occupancy. Lifetime otolith Ba:Ca transects revealed individual variability in the magnitude of residence in oligohaline waters. Using a mean oligohaline occupancy threshold, an estimated 82% of individuals used oligohaline waters at some point in their life. Nonetheless, 66% of individuals spent <20% of their life histories in oligohaline waters, suggesting intermittent and infrequent excursions into low salinity waters. Finally, a literature survey identified 56 peer‐reviewed publications using combinations of otolith chemistry and tissue stable isotope ratios with a wide range of marker pairings and study aims. The diversity of ecological questions that can be asked with the combined use of these two approaches will provide valuable insight into fish ecology. [ABSTRACT FROM AUTHOR]

Migrations between spawning, growth and refuge habitats are critical for many fish species. Partially migratory populations of brook charr Salvelinus fontinalis (known as brook trout in the United States), in which a portion of the population migrates, were once widespread in the Great Lakes region of North America, but are now scarce and a rehabilitation priority. Great Lakes fishery managers lack a simple, non-lethal means to determine whether a large brook charr caught in a Great Lakes accessible stream reach represents a stream-resident fish or migrant that previously spent time foraging and growing in Great Lakes waters. We explored a relatively inexpensive and non-lethal stable isotope approach for documenting lake to stream movements of brook charr, using fin clips from brook charr captured in streams in fall prior to spawning. Using fin tissue from juvenile and adult coho salmon captured in Michigan tributaries to Lake Superior, we confirmed distinct stable isotope signatures indicative of prior stream and Lake Superior foraging. We identified brook charr from tributaries accessible to Lake Superior whose stable isotope signatures were similar to those of lake-captured brook charr, lake charr and splake (a brook charr–lake charr hybrid) and distinct from stable isotope signatures of brook charr in streams inaccessible to Lake Superior fishes, suggestive of an adfluvial migratory pattern. Brook charr from two streams had elevated δ15N values, indicative of previous residency in a downstream lake receiving water from a sewage treatment facility. Our findings demonstrate the utility of stable isotope analysis as a non-lethal technique for confirming adfluvial movements of brook charr from Lake Superior to streams. [ABSTRACT FROM AUTHOR]

Understanding the sources of primary production supporting marine food webs is important for conserving critical habitats. However, the importance of allochthonous versus autochthonous production is often unclear. We identify the sources of primary production supporting three species of predatory fish (Lutjanus carponotatus, Lutjanus fulviflamma, and Lethrinus punctulatus) in the Dampier Archipelago, Western Australia. The proportions of mangrove, seagrass, macroalgae, and suspended particulate organic matter (SPOM) assimilated by fish of different life-history stages and from different habitats were determined using stable isotopes and Bayesian mixing models. While contributions of sources varied among species and habitats, we found that SPOM was an important energetic resource for both adults and juveniles of all three fish species. Juvenile L. carponotatus and L. punctulatus inhabiting macroalgal habitats assimilated more seagrass- and macroalgae-derived material than fish from coral or mangrove habitats, while reliance on mangrove carbon was generally limited overall. Assimilation of macrophyte-derived material decreased throughout ontogeny for L. carponotatus, while L. fulviflamma relied on a combination of SPOM and seagrass into adulthood. The contribution of macroalgae and SPOM to the diets of juvenile L. punctulatus and L. carponotatus from macroalgal habitats varied spatially but was unrelated to seascape configuration, habitat quality, or hydrodynamic conditions. While mixing models suggested a modest degree of trophic connectivity, cross-habitat trophic subsidies provided by macrophytes play a minor role in supporting the studied fish of either life-history stage. Instead, microalgal production predominantly fuels the productivity of predatory fish in this turbid, macrotidal system. [ABSTRACT FROM AUTHOR]

Understanding the leakage routes plays an important role in a successful remediation of water loss by consequently reducing its cost and time. Among the common methods for reducing uncertainty in leakage analysis, the geology, hydrochemistry, environmental isotopes, grouting analysis, water-balance calculations, and water level monitoring are applied at this study to find the dominant leakage routes at the Roudbal Dam site. Results show that two leakage routes are probable, through the karstic limestone at the right bank of reservoir. Leakage along the first route is based on the following evidence: (a) the occurrence of bedding plane conduits; (b) the appearance of leakage in the access gallery down gradient of grout curtain; (c) the similarity of water chemistry and isotopic content; (d) the close correlation of water-level response in open boreholes to fluctuation in reservoir water levels; and (e) inadequate sealeing of grout curtain in depth and length. For the second route, leakage evidence is based on: (a) the interpreted hydraulic connectivity of karst aquifers especially by the presence of springs at transverse faults; (b) the elevation of discharge zones approximately 300 m lower than reservoir water level; (c) the similar water chemistry and isotopic content; (d) the results of water-balance calculations; and (e) no grout curtain was constructed on this route. To reduce uncertainty along any proposed leakage route, a thorough hydrogeological investigations (including spring monitoring, tracer test, borehole drilling and karst assessment) and geophysical evaluation (particularly in sites with complex structure) are needed. It is concluded that to reduce uncertainty in the addressing leakage routes, the applied approach at each dam site must be based specifically on the local geological and hydrogeological conditions. [ABSTRACT FROM AUTHOR]

Trophic niche is the result of the long‐term evolution of species and can reflect the pressures they experience in habitats. The whole‐genome sequencing of giant pandas (Ailuropoda melanoleuca) has indicated that populations distributed in Qinling (QIN) and non‐QIN probably diverged 300 ky ago. Although many studies regarding foraging strategy, habitat preference, and niche partition have been conducted on these populations, there is still a lack of precise quantification of trophic niches. Here, we calculated and compared isotopic trophic niche widths of giant pandas from Sichuan (SC) and QIN populations by measuring carbon and nitrogen isotopes of their hairs; combined with data from sympatric mammals, we explored the relative trophic positions of giant pandas in the ecosystem, respectively. The Stable Isotope Bayesian Ellipses in R (SIBER) model results showed the trophic niche width of QIN pandas was 3.44‰2, which was significantly bigger than those of the SC population (2.03‰2), with an overlapping about 1.45‰2; and they both occupied a unique position in the context, almost one trophic level lower than herbivores. Then, we determined the isotopic ratios of the main foods from the habitats of these pandas; the results suggested that the isotopic difference between bamboo shoots and other parts plus the various feeding selections of pandas on them accounted for pandas' trophic niche widths. We considered the higher nutrition availability and digestible food resources giving QIN pandas a wider trophic niche than pandas from SC. This conclusion provides a new insight into the resource use and trophic ecology of giant pandas and is important to develop refined management plans for the two populations. [ABSTRACT FROM AUTHOR]

• Carbon isotope composition (δ13C) variation among J. curcas genotypes is discrete. • Drought-induced changes in δ13C is remarkable in J. curcas. • δ13C may be used as a tool for screening water-use efficient genotypes in J. curcas. Jatropha curcas L. is a non-food crop quoted as a promising natural feedstock for biodiesel production in tropical and subtropical regions. Although an efficient mechanism of drought avoidance through stomatal control of transpiration has been demonstrated in this species, low carbon assimilation and growth rates preclude any advantage of such strategy under water limitation. Two greenhouse experiments were conducted with the objective of investigating varietal differences in water use as the trade-off between carbon isotope composition (δ13C) in different tissues and water use efficiency, in young plants of J. curcas. The first experiment was a survey with seven provenances of J. curcas under non-limiting water availability. There were no significant differences among provenances for leaf gas exchange rates, growth and whole-plant transpiration (T). However, significant effects of provenance and tissue (stem bark or leaf) in δ13C were demonstrated. The provenances CNPAE183 and CNPAE222 were selected for the second experiment, as variations in water use traits and δ13C between the two provenances were observed. Soil water deficit, imposed for 18 days, led to significant physiological, biochemical, and morphological changes. An early and sharp response to water deficit in CNPAE183 as compared to CNPAE222 was observed, as indicated by a 44% higher rate of decrease of T in the former. In addition, water deficit led to increase of δ13C, which was more pronounced in CNPAE222 (13% in young leaves) when compared to CNPAE183 (11% in young leaves). In both provenances, δ13C was less negative in young as compared to mature tissues. Significant and direct correlations between stem bark and leaf δ13C and leaf-level intrinsic water use efficiency were observed. Contrasting results, particularly on T and δ13C, suggest the existence of genetic diversity for water relations and metabolic traits linked to drought tolerance in J. curcas. Using stem bark or leaf δ13C measurements as the basis for large-scale screening of water-use efficient genotypes should be considered. [ABSTRACT FROM AUTHOR]

The stable isotope analysis of black powder (BP) is of great significance for its comparison and source inference. Previous studies have verified the feasibility of distinguishing different BP samples through stable isotopes. However, the impact of raw materials and synthesis processes on the stable isotopes of BP remains unclear. On the one hand, the raw materials of BP are widely sourced, and whether stable isotopes can distinguish different source materials remains to be studied. On the other hand, the synthesis of BP involves the physical mixing of raw materials, and whether this process leads to isotope fractionation also needs further investigation. To address these problems, stable isotope ratios of 27 charcoals, 15 potassium nitrates, 6 self‐made and 10 commercial BP samples were analyzed. The results showed that the stable isotope ratios can be utilized to distinguish charcoals and potassium nitrates from different manufacturers and batches. No significant differences in the nitrogen and oxygen stable isotope ratios between the self‐made BP and its raw materials were observed, indicating that the physical mixing process does not induce significant fractionation of stable isotopes. However, the carbon stable isotope ratios of charcoal increased (within 2SD) after being synthesized into BP. Due to the utilization of additives and variations in the synthesis process, the correlation between the stable isotope ratios of commercial BP and its raw materials was complex. The findings of this study provide a scientific reference for tracing the source of BP. [ABSTRACT FROM AUTHOR]

Chlorophyllous plants exhibiting partial mycoheterotrophy obtain carbon through mycorrhizal interactions in addition to photosynthesis. In arbuscular mycorrhizal (AM) plants, the Paris‐morphotype (i.e. hyphal coils) is considered essential for mycoheterotrophic carbon gains. Numerous tree species in tropical lowland forests form this morphotype, and under light‐ and nutrient‐limitation, additional carbon gain would be beneficial. However, if seedlings of woody species in the understory of tropical lowland forests exhibit partial mycoheterotrophy remains unexplored. Here we (a) examined the AM morphotype (Paris‐ or Arum‐type) in seedlings of 41 tropical woody species, and (b) to determine if any of the target Paris‐type species are partially mycoheterotrophic, we compared their multi‐element stable isotope natural abundance (13C, 2H, 18O, 15N) with neighbouring autotrophic non‐Paris‐type reference seedlings. About 50% of the investigated species (and 80% of the genera) exhibited the Paris‐type, expanding the number of tropical plant genera with Paris‐type AM. Enrichment in 13C, but not in 18O in target compared with neighbouring reference plants indicated partial mycoheterotrophy in seedlings of 6 of the 21 investigated Paris‐type AM species. Our results indicate for the first time that carbon gain through mycoheterotrophy occurs in seedlings of AM tropical tree species. In tropical forests, partial mycoheterotrophy during seedling establishment may confer so far unrecognised ecological advantages influencing seedling recruitment and ecosystem dynamics. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

We have been developing a novel 99Mo/99mTc generator production method using a water-insoluble porous MoO2 target. In this method, the extraction of 99mTc from MoO2 is achieved by leveraging the difference in their water solubilities. The fabrication of a porous MoO2 pellet, and the water extraction of 99mTc from neutron irradiated porous MoO2 were conducted. The results confirmed 99mTc extraction with a low Mo/Tc ratio. Additionally, the dissolution rate of radioactive 99Mo was found to be higher than stable isotopes of molybdenum, i.e., confirming the hot atom effect on the dissolution of molybdenum in (n, γ ) reaction. [ABSTRACT FROM AUTHOR]

Nitrogen stable isotope ratios (δ15N) are widely used to quantify trophic position in aquatic ecosystems. Comparing trophic position across space requires identifying baselines to account for variation in δ15N values of basal energy resources, but few standardized methods exist for identifying suitable baselines. We evaluated a standardized method for identifying optimal isotopic baselines in streams spanning the Rocky Mountains–Great Plains ecotone. We assessed candidate taxonomic groups and feeding groups following four criteria: (1) Organisms should be easy to collect and widely distributed, (2) Within-site δ15N variation should be low (representative of uniform feeding behavior), (3) δ15N values should be correlated with geographic variability in δ15N values, and (4) Trophic position of consumers calculated using the baseline should be independent of geographic δ15N variability when there is no change in diet. Simuliidae (obligate, sestonic filter feeders) met all four criteria for four fishes and produced trophic position estimates consistent with dietary changes for brown trout along a longitudinal stream gradient. The four-criteria screening method is suitable for temperate streams in North America and supports the recommendation to use Simuliidae or potentially grouped filter feeders as baseline organisms for stable isotope studies quantifying trophic position in higher-order consumers. [ABSTRACT FROM AUTHOR]

Urbanization transforms natural river channels, and surface water of some rivers disappeared over time. How and whether the subsurface domains of the original waterways and aquifers connecting them (a phantom of historical landscape) are functional is not known. This study examined the effects of tributary groundwater inflow on the response of river–riparian organisms in an alluvial mainstem river in northern Japan, where the tributary disappeared over the course of urban landscape transformation.A 2.8‐km lowland segment of the mainstem gravel‐bed river was examined for water properties and the river–riparian food web. In addition, watershed‐wide water sampling was conducted to isotopically distinguish several types of groundwater that contributed to the hyporheic water in the study segment. Altitude had a clear effect on the hydrogen/oxygen stable isotope ratios in the river water collected across the watershed.Groundwater unique both in chemical and isotopic signatures occurred in several spots within the study segment, and its properties resembled and its upwelling locations matched groundwater from a tributary river whose surface channel disappeared 60 years ago. Positive numerical increases in abundance and/or a sign of nitrogen transfer in river–riparian communities (algae, invertebrates and riparian trees) originating from groundwater high in nitrate with elevated nitrogen stable isotope ratios were found.We demonstrated that tributary groundwater with unique chemical properties manifested by an urban watershed river network continued to have trophic effects on biota across the river–riparian boundary in the mainstem river, even after urbanization transformed the tributary into a phantom river. We highlighted the legacy effects of landscape transformation in the subsurface domain and the significance of scrutinizing the past landscape and hydrological connectivity at the watershed scale in urban environments. [ABSTRACT FROM AUTHOR]

The Roman mill complex of Barbegal in France is the largest preindustrial structure in Europe. Carbonate incrustations that formed from water flowing through basins, over flumes and waterwheels of the mill complex are partly preserved. The largest carbonate fragments are derived from three wooden flumes that once served the wheels of three mills in a train of eight. The deposits formed from the same water as it moved down from mill to mill. The shape, microstratigraphy and stable isotope patterns of the deposits of each flume reveal a unique history of use for each mill during the last 8 years of operation until their final abandonment. The sidewall carbonate deposits of the flumes vary in shape due to differences in the slope of the flumes during operation, associated with different‐size millwheels in different basins. At least one of the flumes must have been mobile and was uplifted to fit a millwheel of a different size. During 8 years, two millwheels were exchanged and one flume was taken out of action. Carbonate deposits from two flumes were subsequently reused for some unknown industrial purpose in a water basin, and one was later embedded as spolia in a building during late antiquity. [ABSTRACT FROM AUTHOR]

The emporion of Pech Maho was destroyed after a warlike event at the end of the third century BC. Shortly after that, around 200 BC, the site was resettled. This reuse is characterised above all by massive deposits of equid carcasses in various locations around the city. The conditions of these deposits are investigated in this paper. We focus on examining several biological parameters (weight, age and sex) of the equid population, as well as their feeding habits, using three different proxies: stable isotope, dental meso- and microwear. This interdisciplinarity gives us access to the overall equid diet, as well as to the diet during the last phases of their lives. This population is largely dominated by small size young adult males. Isotopic as well as morphometric analyses indicate that they were bred in various locations before being brought to Pech Maho. Dental wear analyses show that they experienced the same feeding throughout their lives and just before their death. The animals were all slaughtered within a short period of time. This study illustrates the advantages of combining proxies in order to enhance our understanding of the life and death conditions of Iron Age equids. [ABSTRACT FROM AUTHOR]

The faunal remains from the late Neolithic site of Ness of Brodgar on the Orkney Islands (UK) provide a unique opportunity to investigate past adaptations of animal husbandry strategies to the Northern island environment, as well as the potential management of red deer. In this study, sheep and red deer mandibles and loose teeth (dP4 & M3) from the Ness of Brodgar were studied to construct age-at-death profiles, and analysed for δ13C, δ15N and δ18O. The mortality profile showed that around half of the analysed sheep were slaughtered when they reached maturity (i.e. after 2–4 years of life), consistent with a husbandry regime targeted at meat production. The stable isotope evidence indicates seaweed consumption in winter by several sheep (domesticates), but not by red deer (wild, possibly managed fauna). This dietary difference may have resulted from anthropogenically mediated influences, e.g. restriction of red deer habitats to upland areas. The varying extent of seaweed consumption between individual sheep and between Neolithic Orkney sites suggests differences in sheep husbandry practices across Orkney, indicating that the adaptation to consume seaweed was not ubiquitous on Orkney in the Neolithic, and did not follow a linear development. [ABSTRACT FROM AUTHOR]

Against the backdrop of global warming, the dynamics of glaciers and their water resources have significant implications for hydrological processes in the arid regions of Northwest China. The Aksu River, which is an essential inland river enriched by substantial meltwater contributions, plays a pivotal role in the economic, ecological, and social development of the region. Based on 231 water samples collected during the period of intense glacial ablation in 2023, this study conducted a comprehensive analysis of the hydrochemical and stable isotopic characteristics of the Little Kurgan glacial basin in the Aksu River source region. A Piper diagram classified the hydrochemical type of the river water as Calcium–Bicarbonate. Analysis based on a Gibbs diagram indicated that rock weathering is the predominant factor affecting the hydrochemical properties within the studied basin. Through application of principal component analysis and end-member mixing analysis, it was determined that the glacier meltwater contribution to runoff was 67%, 61%, and 55% in July, August, and September, respectively. The findings of this study reveal that glacier meltwater is the principal component of the river water, and highlight the critical impact of alterations in glacier ablation on the hydrological cycle within the Aksu River source region, which is vitally important for sustainable water resource management. [ABSTRACT FROM AUTHOR]

Effective management of Water Supply Systems (WSSs) is crucial for ensuring safe drinking water. The WSS of Varaždin County is a complex network involving three groundwater sources: Bartolovec and Vinokovščak wellfields (alluvial aquifers) and Bela karstic spring. To achieve a comprehensive characterization of WSSs, routine laboratory data was integrated with stable isotopes and geochemical modeling. Within this study, all measured parameters remain below the Maximum Contaminant Level (MCL), ensuring water safety for human consumption. The Piper diagram identified variations in water sources based on their chemical composition, providing a simplified overview of mixing patterns within WSSs. Among the modeling approaches, inverse modeling (IM) was found to be more reliable than forward modeling (FM) and mass balance modeling (MB). Despite the limited capacity of δ18O to provide accurate mixing results, it was revealed that the reservoir water was in equilibrium with the air (no evaporation effects), indicating well-sealed reservoirs. Mixing modeling showed that the western, southwestern, and northern parts of the WSS mixed all three sources, whereas the eastern and southeastern areas primarily relied on the deeper aquifer of the Bartolovec source, indicating potential vulnerability. Strict validation criteria ensured the reliability of results, demonstrating the effectiveness and applicability of geochemical modeling in water security management plans. [ABSTRACT FROM AUTHOR]

In line with the Sustainable Development Goals, a comprehensive understanding and precise quantification of the temporal and spatial characteristics of water quality is essential to identify sources of pollution in basins and to protect river headwaters to maintain water safety throughout basins. However, there is a lack of systematic quantitative tracking of seasonal river pollution sources in hilly areas in southwest China. In this study, the spatial and temporal characteristics of the water environmental factors in the Yaoshi River basin, the causes of pollution, and the main sources of nitrogen pollution were systematically investigated using geographic information systems and statistics. The results showed that the main pollutants in the river as a whole included five-day biological oxygen demand (BOD5), oxygen demand (COD), ammonium (NH4+), total phosphorus (TP), and total nitrogen (TN). Nitrogen pollution was the most serious, and various environmental factors caused seasonal variations and different spatial distributions in this pollutant. Temporally, the TP and COD concentrations were highest during the wet season, while the NH4+, TN, and BOD5 concentrations were highest during the dry season. Spatially, BOD5, COD, and TP concentrations were ranked upstream < downstream < midstream, while TN and NH4+ concentrations were ranked downstream < midstream < upstream. The main sources of pollution in the study area were domestic activities (34.94%), agricultural activities (40.12%), and mixed organic and natural sources (24.94%). Notably, manure effluent dominates nitrate nitrogen sources, while fertilizer inputs minimally contribute during mean-flow and dry seasons, and atmospheric deposition contributes during the wet season. These findings provide important data for improving water quality in the Yaosi River Basin, promoting sustainable agricultural practices, alleviating water scarcity, and advancing the region's Sustainable Development Goals. In addition, this study can provide reference for the development of sustainable development management strategies for seasonal rivers in other hilly areas and promote broader environmental sustainability efforts. [ABSTRACT FROM AUTHOR]

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This study investigated the basement aquifer beneath the urbanised city of Niamey and the agricultural fields of Kollo, SW of Niger. During the observation period spanning from 2021 to 2023, groundwater and surface water samples were collected for analysis of major ions and the stable isotopes oxygen-18 and deuterium (δ18O and δ2H) of water. To trace the origin of high nitrate concentrations (NO3−) found in several observation and drinking water wells in both areas, δ15N and δ18O isotope values of NO3− were analysed in groundwater and eluted soil samples. The observed hydrochemical patterns mainly reflect the heterogeneity of the weathered fringe of the basement aquifer. Decreasing concentrations of NO3− and δ18O and δ2H values were observed in relation to the distance of the Niger River and increasing thickness of the clay layer on the surface. The wells close to the river in Niamey show a dilution effect during the flood season, and the NO3− concentrations displayed a continuous increasing trend. The δ15N-NO3 and δ18O-NO3 values confirmed that septic tank water is spreading in the region of Niamey and that manure originating from livestock in Kollo is the main source of NO3−. The patterns of δ15N in the soil samples coincide with those of cattle's manure spread in both areas. The shallow wells show significantly higher values of electric conductivity and NO3− concentrations compared to the deeper wells, which clearly indicates the influence of shallow septic tanks on water quality. [ABSTRACT FROM AUTHOR]

High-value products, such as hazelnuts, are particularly vulnerable to fraud due to their price dependence on geographical origin. Guaranteeing hazelnuts' authenticity is essential for consumer trust and safety. Stable isotope analysis has become a reference method for origin authentication as it is reliable, robust, and easily transferable across laboratories. However, multiple isotopic markers coupled with chemometric techniques are often needed to authenticate food provenance accurately. In this study, we focused on assessing the potential of bulk δ18O, along with δ2H and δ13C of the main fatty acids, as hazelnut-origin authenticity markers. PLS-DA classification models were developed to differentiate samples (n = 207) according to their region of origin. This multi-isotopic approach provided promising external validation results, achieving a 94% global correct classification rate in discriminating hazelnuts from regions with distinct geographical and environmental conditions. This study lays the groundwork for further model development and evaluation across additional production areas and harvest years. [ABSTRACT FROM AUTHOR]

Globalization and free market dynamics have significantly impacted state economies, particularly in the wine industry. These forces have introduced greater diversity in wine products but have also heightened the risk of food fraud, especially in high-value commodities like wine. Due to its market value and the premium placed on quality, wine is frequently subject to adulteration. This issue is often addressed through regulatory trademarks on wine labels, such as Protected Designation of Origin (PDO) and Protected Geographic Indication (PGI). In this context, the metabolic profiles (organic acids, carbohydrates, and phenols) and stable isotope signatures (δ13C, δ18O, D/HI, and D/HII) of red and white wines from four agroclimatically similar regions were examined. The study explored how factors such as grape variety, harvest year, and geographical origin affect wine composition, with a particular focus on distinguishing samples from cross-border areas. Multivariate statistical analysis was used to assess the variability in wine composition and to identify distinct groups of samples. Preliminary results revealed that organic acids and volatile compounds were found in lower concentrations than carbohydrates but were significantly higher than phenols, with levels ranging between 1617 mg/L and 6258 mg/L. Carbohydrate content in the wines varied from 8285 mg/L to 14662 mg/L. Principal Component Analysis (PCA) indicated certain separation trends based on the variance in carbohydrates (e.g., fructose, glucose, galactose) and isotopic composition. However, Discriminant Analysis (DA) provided clear distinctions based on harvest year, variety, and geographical origin. [ABSTRACT FROM AUTHOR]

We report the δ142/140Ce values for thirty‐three widely available geological reference materials (RMs), including igneous rocks, metamorphic rocks, sediments and soils. The Ce isotope ratios of twenty‐two Chinese RMs are reported for the first time. After chemical purification using TODGA resin (50–100 μm, Eichrom, USA), Ce isotope measurements of these RMs were conducted by multi‐collector inductively coupled plasma‐mass spectrometry (MC‐ICP‐MS) with a combined standard‐sample bracketing (SSB) and Sm‐doping technique. The data quality of the Ce isotope results was assessed by repeated measurement of pure Ce reference solutions (NIST SRM 3110, JMC304, CDUT‐Ce) and well‐characterised geological RMs (BHVO‐2, BCR‐2, Nod‐A‐1, Nod‐P‐1, etc.). Our results are in excellent agreement with previously reported values within intermediate measurement precision (±0.04‰, 2s). The igneous rock and soil RMs showed limited variations in δ142/140Ce values, which ranged from ‐0.036 ± 0.018‰ to 0.062 ± 0.046‰ and ‐0.015 ± 0.015‰ to 0.029 ± 0.009‰, respectively. The river/marine sediments and Mn nodules displayed variable Ce isotope ratios ranging from ‐0.005 ± 0.018‰ to 0.141 ± 0.023‰, suggesting detectable Ce isotopic fractionation during low‐temperature processes. [ABSTRACT FROM AUTHOR]

Disentangling the determinants of trophic structure is central to ecology. The capacity to capture subjugate and consume a prey (i.e. gape limitation) is a relevant limitation to acquire energy for most organisms, especially those in smaller size ranges. This generates a size hierarchy of trophic positions in which large organisms consume small ones. Body size is tightly correlated to gape limitation and explains a large fraction of variance in the body size‐trophic position relationship. However, a considerable fraction of variance still remains to be explained. Consumer search space dimensionality (2D or 3D) and feeding strategies, temperature and the size structure of primary producers can alter the trophic structure, but tests based on information from natural food webs are scarce. We generated specific predictions about the body size trophic position relationship and evaluated them using information from a subtropical South Atlantic coastal marine ecosystem: benthic realm (2D, rocky shore and sandy beach) and the pelagic realm (3D). We characterized this marine coastal food web based on stable isotopes of carbon and nitrogen from 256 samples from primary producers (macroalgae and phytoplankton) to large predators (sand shark) in summer and winter. Consumer body size encompassed six orders of magnitude in weight from 10−2 to 6 × 104 g. Isotopic signal corresponded to an integration of carbon sources from basal consumers to top predators. The body size‐trophic position relationship showed a linear positive association with different slopes for the benthic and pelagic environments. This implies a smaller predator prey size ratio for pelagic (3D) with respect to benthic consumers (2D) as theoretically expected. No seasonal differences were found in slopes and most of the overall variance in benthic environments was largely explained by feeding strategies of the different taxonomic groups. We provide an integrated evaluation on the role of body size, consumer search space and feeding strategy to understand the determinants of trophic position. Results demonstrate that integrating gape limitation hypothesis, the dimensionality of consumer search space and feeding strategies into a formal robust framework to understand trophic structure is feasible even in complex natural ecosystems. [ABSTRACT FROM AUTHOR]

A multi-proxy study of biotic and abiotic components was conducted on surface sediment samples from six lakes/wetlands located along the western transitional boundary of the contemporary Indian Summer Monsoon (ISM) in the Indian Subcontinent. The primary goal is to assess the suitability of various proxies as representatives of modern vegetation, environmental and climatic conditions. The collected data indicate significant variations in the composition and density of pollen in response to climate-induced and anthropogenic ecological changes throughout the northwest India transect. The palynological studies from eastern Rajasthan shows high forest elements in comparison to western Haryana and western Uttar Pradesh. In addition, the palynological data was juxtaposed with other biotic proxies such as diatom and isotopic studies, along with geochemical proxies and paleomagnetic data of the surface lake sediments. The presence of marker pollen taxa including Cerealia type Poaceae, Chenopodiaceae, and Brassicaceae, allows for distinct recognition of anthropogenic activities throughout the whole transect. The diversity and distribution of diatoms also support the palynological data in response to climate-induced and anthropogenic ecological changes. Furthermore, grain size, geochemistry (TOC/TN ratio with stable carbon isotope), and magnetic susceptibility data offer crucial insights about the sediment's depositional settings and general mineralogical composition. Stable carbon isotope data shows C 3 dominance in relatively humid areas and C 4 dominance in semi-arid areas, suggesting climate-driven control over sediment organic matter composition. Canonical correspondence analysis (CCA) indicates that biotic variables (pollen, diatom, stable isotopic composition) are significantly controlled by modern precipitation and temperature. Redundancy analysis reveals a significant influence of current average temperature and precipitation on major element oxide variations in surface lake sediments. Therefore, we propose using palynological, stable carbon isotope, diatom data, along with grain size, environmental magnetism, and geochemistry, to establish a multiproxy modern analogue for quantitative palaeoclimatic reconstructions. As a result, this study provides the first modern analogues from a climate-sensitive region that separates the area under ISM influence from an area with meager precipitation in western India. [Display omitted] [ABSTRACT FROM AUTHOR]

Rationale: Rapid, accurate, and easy‐to‐perform diagnostic assays are required to address the current need for the diagnosis of resistant pathogens. That is particularly the case for mycobacteria, such as the human pathogen Mycobacterium tuberculosis, which requires up to 2 weeks for the determination of the drug susceptibility profile using the conventional broth microdilution method. To address this challenge, we investigated the incorporation of deuterium, the stable isotope of hydrogen, into lipids as a read out of the drug susceptibility profile. Methods: Deuterium is incorporated into newly synthesized proteins or lipids in place of hydrogen as bacterial cells grow, increasing the mass of the macromolecules, which can then be observed via matrix‐assisted laser desorption ionization time of flight mass spectrometry (MALDI‐TOF MS). As proof‐of‐concept, we used the non‐pathogenic Mycobacterium smegmatis mc2155 strain, which is susceptible to the aminoglycoside antibiotic kanamycin, and M. smegmatis mc2155 containing the empty vector pVV16, which is kanamycin‐resistant. Bacteria were incubated in a culture medium containing 50% of deuterium oxide (D2O) and either 1 or 2 times the minimal inhibitory concentration (MIC50) of kanamycin. Lipids were then analyzed using the MBT lipid Xtract matrix combined with routine MALDI mass spectrometry in the positive ion mode to evaluate the changes in the lipid profile. Results: Using this approach, we were able to distinguish susceptible from resistant bacteria in less than 5 h, a process that would take 72 h using the conventional broth microdilution method. Conclusions: We therefore propose a solution for the rapid determination of drug susceptibility profiles using a phenotypic assay combining D2O stable isotope labelling and lipid analysis by routine MALDI mass spectrometry. [ABSTRACT FROM AUTHOR]

The major ion and stable isotope geochemistry of coalmine water of Talcher coalfield was investigated to identify prominent hydrogeochemical processes controlling mine water composition and estimate annual elemental flux. Mine water samples from opencast and underground coalmines were analysed for EC, pH, TDS, TH, major ions and stable isotopes i.e. δ18O and δ2H. Coalmine water exhibited a wide range of pH values, from highly acidic to alkaline, and were dominated by SO42− and Ca2+ in their total anionic (TZ−) and cationic (TZ+) composition respectively. Ca-Mg-SO4 was the most dominant hydrochemical facies. High contribution of Ca2+and Mg2+ and SO42− towards the TZ+ and TZ− and low HCO3−/(HCO3−+SO42−) ratio suggested a major role of sulphide oxidation in determining coalmine water chemistry. A slight deviation in the regression line towards right side of the Global Meteoric Water Line and Local Meteoric Water Line in the bivariate plot of δ18O vs δ2H implied that water experienced evaporation to some extent and originated mainly from atmospheric precipitation. Most of the mine water were undersaturated with respect to carbonate and sulphide phases. Talcher coal mines annually delivered 47.06 × 106 m3 mine water and 28.481 × 103 tonnes of solute loads into nearby drainage. [ABSTRACT FROM AUTHOR]

Urban rivers worldwide have been increasingly threatened by nitrate (NO3−) pollution. The Xianyang-Xi'an segment of the Weihe River, located in the loess plateau with serious soil erosion, has been highly urbanized and with intensive agricultural activities. Tracing the sources and transformations of NO3− is particularly challenging for this watershed which has multiple N sources and variable environmental factors. In this study, integrating antecedent studies with multiple stable isotopes and MixSIAR models, these river basins can be categorized into three classes: (1) urban areas, sewage, and manure were the predominant sources of NO3− in the Weihe River's mainstream, accounting for 73.4 ± 12.8%; (2) suburban areas, sewage and manure (Fenghe River, 58.0 ± 14.0%; Bahe River, 53.9 ± 15.0%) were recognized as the main sources of NO3−; (3) and the rural areas, ammonium nitrogen fertilizers were identified as the primary source of NO3− in the Heihe and Laohe Rivers. In addition, nitrification dominated the mainstream of the Weihe, Fenghe, and Bahe Rivers, while neither denitrification nor nitrification was evident in the Heihe and Laohe Rivers. In conclusion, this study is important for the improvement of surface water quality of rivers with different land use types and the development of targeted water environment management. [ABSTRACT FROM AUTHOR]