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1
Siliézar, Alicia, Sandra Pichler, Gabriele Graenert, and Claudia Gerling. "Ernährung im frühmittelalterlichen Gurmels : Analysen stabiler Isotope an merowingerzeitlichen Individuen vom Dürrenberg FR." Jahrbuch Archäologie Schweiz = Annuaire d'Archéologie Suisse = Annuario d'Archeologia Svizzera 107 (2024) (June 18, 2024): 165–79. https://doi.org/10.5281/zenodo.10998026.
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Keywords: Frühmittelalter; Merowingerzeit; Gurmels; Dürrenberg; Bestattungen; stabile Isotopenanalysen; Ernährung; Gesellschaft. – Haut Moyen Âge ; époque mérovingienne ; Cormondes ; Dürrenberg ; inhumations ; analyses des isotopes stables ; alimentation ; société. – Alto Medioevo; periodo merovingio; Gurmels; Dürrenberg; sepolture; analisi degli isotopi stabili; nutrizione; società. – Early Middle Ages; Merovingian period; Gurmels; Dürrenberg; burials; stable isotope analyses; diet; society.
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Marie, Balasse, Gillis Rosalind, Živaljević Ivana, et al. "Seasonal calving in European Prehistoric cattle and its impacts on milk availability and cheese-making." Scientific Reports 11 (April 14, 2021): 8185. https://doi.org/10.5281/zenodo.4688720.
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Present-day domestic cattle are reproductively active throughout the year, which is a major asset for dairy production. Large wild ungulates, in contrast, are seasonal breeders, as were the last historic representatives of the aurochs, the wild ancestors of cattle. Aseasonal reproduction in cattle is a consequence of domestication and herding, but exactly when this capacity developed in domestic cattle is still unknown and the extent to which early farming communities controlled the seasonality of reproduction is debated. Seasonal or aseasonal calving would have shaped the socio-economic practices of ancient farming societies differently, structuring the agropastoral calendar and determining milk availability where dairying is attested. In this study, we reconstruct the calving pattern through the analysis of stable oxygen isotope ratios of cattle tooth enamel from 18 sites across Europe, dating from the 6<sup>th</sup> mill. cal BC (Early Neolithic) in the Balkans to the 4<sup>th</sup> mill. cal BC (Middle Neolithic) in Western Europe. Seasonal calving prevailed in Europe between the 6<sup>th</sup> and 4<sup>th</sup> millennia cal BC. These results suggest that cattle agropastoral systems in Neolithic Europe were strongly constrained by environmental factors, in particular forage resources. The ensuing fluctuations in milk availability would account for cheese-making, transforming a seasonal milk supply into a storable product.
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Benbow, Timothy J., Alan R. Hayman, Robert Van Hale, and Russell Frew. "Preparation of aqueous fatty acids for hydrogen and carbon stable isotope analysis by solid phase extraction." Marine and Freshwater Research 64, no. 4 (2013): 294. http://dx.doi.org/10.1071/mf12192.
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Stable isotope analyses of fatty acids in environmental waters provides important information as to their source(s). Analysis is often confounded due to low concentrations of fatty acids and/or a complex sample matrix requiring separation of the target analyte. The purpose of this study was to validate a method to extract fatty acids from natural waters using solid phase extraction (SPE) before compound specific isotope analysis (CSIA). Three SPE cartridges and multiple eluting solvents were tested to determine the efficiency, isotopic fractionation, and reproducibility of each extraction technique. Our results indicated that surface-modified styrene divinylbenzene cartridges, when eluted with methanol, caused negligible fractionation of the hydrogen isotopes and minimal fractionation of the carbon isotopes, but that isotopic fractionation occurred when compounds were only partially eluted from SPE cartridges. Compounds were also extracted from landfill leachate using both SPE and liquid–liquid extraction (LLE). The hydrogen isotope composition (δ2H) of compounds extracted from water using either method were within experimental precision and the carbon isotope composition (δ13C) of all but one fatty acid were within experimental precision. Therefore, these experiments prove the aforementioned SPE methods to be a convenient and precise method to extract fatty acids from natural waters before CSIA.
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Jensen, Alexandria, William Ford, James Fox, and Admin Husic. "Improving In-Stream Nutrient Routines in Water Quality Models Using Stable Isotope Tracers: A Review and Synthesis." Transactions of the ASABE 61, no. 1 (2018): 139–57. http://dx.doi.org/10.13031/trans.12545.
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Abstract. Water quality models serve as an economically feasible alternative to quantify fluxes of nutrient pollution and to simulate effective mitigation strategies; however, their applicability is often questioned due to broad uncertainties in model structure and parameterization, leading to uncertain outputs. We argue that reduction of uncertainty is partially achieved by integrating stable isotope data streams within the water quality model architecture. This article outlines the use of stable isotopes as a response variable within water quality models to improve the model boundary conditions associated with nutrient source provenance, constrain model parameterization, and elucidate shortcomings in the model structure. To assist researchers in future modeling efforts, we provide an overview of stable isotope theory; review isotopic signatures and applications for relevant carbon, nitrogen, and phosphorus pools; identify biotic and abiotic processes that impact isotope transfer between pools; review existing models that have incorporated stable isotope signatures; and highlight recommendations based on synthesis of existing knowledge. Broadly, we find existing applications that use isotopes have high efficacy for reducing water quality model uncertainty. We make recommendations toward the future use of sediment stable isotope signatures, given their integrative capacity and practical analytical process. We also detail a method to incorporate stable isotopes into multi-objective modeling frameworks. Finally, we encourage watershed modelers to work closely with isotope geochemists to ensure proper integration of stable isotopes into in-stream nutrient fate and transport routines in water quality models. Keywords: Isotopes, Nutrients, Uncertainty analysis, Water quality modeling, Watershed.
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Arnoldi, Jean-François, Jenny Rose Bortoluzzi, Hugh Rowland, et al. "How strongly does diet variation explain variation in isotope values of animal consumers?" PLOS ONE 19, no. 6 (2024): e0301900. http://dx.doi.org/10.1371/journal.pone.0301900.
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Analysis of stable isotopes in consumers is used commonly to study their ecological and/or environmental niche. There is, however, considerable debate regarding how isotopic values relate to diet and how other sources of variation confound this link, which can undermine the utility. From the analysis of a simple, but general, model of isotopic incorporation in consumer organisms, we examine the relationship between isotopic variance among individuals, and diet variability within a consumer population. We show that variance in consumer isotope values is directly proportional to variation in diet (through Simpson indices), to the number of isotopically distinct food sources in the diet, and to the baseline variation within and among the isotope values of the food sources. Additionally, when considering temporal diet variation within a consumer we identify the interplay between diet turnover rates and tissue turnover rates that controls the sensitivity of stable isotopes to detect diet variation. Our work demonstrates that variation in the stable isotope values of consumers reflect variation in their diet. This relationship, however, can be confounded with other factors to the extent that they may mask the signal coming from diet. We show how simple quantitative corrections can recover a direct 1:1 correlation in some situations, and in others we can adjust our interpretation in light of the new understanding arising from our models. Our framework provides guidance for the design and analysis of empirical studies where the goal is to infer niche width from stable isotope data.
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Li, Xiangnan, Baisha Weng, Denghua Yan, et al. "Anthropogenic Effects on Hydrogen and Oxygen Isotopes of River Water in Cities." International Journal of Environmental Research and Public Health 16, no. 22 (2019): 4429. http://dx.doi.org/10.3390/ijerph16224429.
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Stable hydrogen and oxygen isotopes are important indicators for studying water cycles. The isotopes are not only affected by climate, but are also disturbed by human activities. Urban construction has changed the natural attributes and underlying surface characteristics of river basins, thus affecting the isotopic composition of river water. We collected urban river water isotope data from the Global Network for Isotopes in Rivers (GNIR) database and the literature, and collected river water samples from the Naqu basin and Huangshui River basin on the Tibetan Plateau to measure hydrogen and oxygen isotopes. Based on 13 pairs of urban area and non-urban area water samples from these data, the relationship between the isotopic values of river water and the artificial surface area of cities around rivers was analyzed. The results have shown that the hydrogen and oxygen isotope (δD and δ18O) values of river water in urban areas were significantly higher than those in non-urban areas. The isotopic variability of urban and non-urban water was positively correlated with the artificial surface area around the rivers. In addition, based on the analysis of isotope data from 21 rivers, we found that the cumulative effects of cities on hydrogen and oxygen isotopes have led to differences in surface water line equations for cities with different levels of development. The combined effects of climate and human factors were the important reasons for the variation of isotope characteristics in river water in cities. Stable isotopes can not only be used to study the effects of climate on water cycles, but also serve as an important indicator for studying the degree of river development and utilization.
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Sedaghatpour, Fatemeh, and Stein B. Jacobsen. "Magnesium stable isotopes support the lunar magma ocean cumulate remelting model for mare basalts." Proceedings of the National Academy of Sciences 116, no. 1 (2018): 73–78. http://dx.doi.org/10.1073/pnas.1811377115.
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We report high-precision Mg isotopic analyses of different types of lunar samples including two pristine Mg-suite rocks (72415 and 76535), basalts, anorthosites, breccias, mineral separates, and lunar meteorites. The Mg isotopic composition of the dunite 72415 (δ25Mg = −0.140 ± 0.010‰, δ26Mg = −0.291 ± 0.018‰), the most Mg-rich and possibly the oldest lunar sample, may provide the best estimate of the Mg isotopic composition of the bulk silicate Moon (BSM). This δ26Mg value of the Moon is similar to those of the Earth and chondrites and reflects both the relative homogeneity of Mg isotopes in the solar system and the lack of Mg isotope fractionation by the Moon-forming giant impact. In contrast to the behavior of Mg isotopes in terrestrial basalts and mantle rocks, Mg isotopic data on lunar samples show isotopic variations among the basalts and pristine anorthositic rocks reflecting isotopic fractionation during the early lunar magma ocean (LMO) differentiation. Calculated evolutions of δ26Mg values during the LMO differentiation are consistent with the observed δ26Mg variations in lunar samples, implying that Mg isotope variations in lunar basalts are consistent with their origin by remelting of distinct LMO cumulates.
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Fitzsimons, I. C. W., B. Harte, and R. M. Clark. "SIMS stable isotope measurement: counting statistics and analytical precision." Mineralogical Magazine 64, no. 1 (2000): 59–83. http://dx.doi.org/10.1180/002646100549139.
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AbstractAnalytical precision is vital in the interpretation of stable isotope data collected by secondary ion mass spectrometry (SIMS) given the small analysis volumes and the small magnitude of natural isotopic variations. The observed precision of a set of measurements is represented by the standard deviation(precision of an individual measurement) or the standard error of the mean (precision of the mean value). The SIMS data show both systematic variations with time and random Poisson variability, but the former largely cancel out when data for two different isotopes are expressed as a ratio. The precision of a SIMS isotope ratio routinely matches that predicted by Poisson counting statistics and can approach that of conventional bulk analysis techniques for counting times of several hours. All sample analyse must be calibrated for instrumental mass fractionation using SIMS analyses of a standard material. There is often a gradual drift in the mass fractionation with time, but this can be modelled by least-squares regression of the standard isotope ratios. Drift in the sample analyses is eliminated by using the relevant point on this regression line to calibrate each sample. The final precision of a corrected isotope ratio must take into account the scatter in both the sample and the standard data.
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Miljević, Nada, and Dušan Golobočanin. "Potential Use of Environmental Isotopes in Pollutant Migration Studies." Archives of Industrial Hygiene and Toxicology 58, no. 2 (2007): 251–62. http://dx.doi.org/10.2478/v10004-007-0015-5.
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Potential Use of Environmental Isotopes in Pollutant Migration StudiesThis article presents the use of natural abundance stable isotope (hydrogen, carbon, nitrogen, oxygen, chlorine) analysis data as a tool for providing important information about the origin of contaminants, the contribution of different sources to a multi-source plume, characterisation of their complex transport (rate and mechanisms) and for evaluating the success of contaminated site remediation. Isotopic signatures of contaminants are useful tracers of their sources, while isotopic fractionation can be used to quantitatively assess the progress of an environmental process such as biodegradation. This new isotopic approach is reliable and can offer more information than traditional techniques in pollutant migration studies, particularly after waste disposal. During biological degradation of any organic compound, molecules containing lighter isotopes are degraded, and the portion of heavier isotopes in the substrate is increased, identifying specific microbial roles in biogeochemical cycling. Since isotopic fractionation is proportional to degradation, depending on the type of contamination, a microbial degradation of 50% to 99% of the initial concentration can be quantified using isotope ratio measurements.
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Merrett, Deborah C., Christina Cheung, Christopher Meiklejohn, and Michael P. Richards. "Stable isotope analysis of human bone from Ganj Dareh, Iran, ca. 10,100 calBP." PLOS ONE 16, no. 3 (2021): e0247569. http://dx.doi.org/10.1371/journal.pone.0247569.
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We report here on stable carbon, nitrogen, and sulfur isotope values from bone collagen of human (n = 20) and faunal (n = 11) remains from the Early Neolithic site of Ganj Dareh, Iran, dating to ca. 10,100 cal. BP. Our focus explores how isotope values of human bone vary by age and sex, and evaluates dietary practices at this site. It also provides a baseline for future studies of subsistence in the early Holocene Central Zagros Mountains, from the site with the first evidence for human ovicaprid management in the Near East. Human remains include individuals of all age groups for dietary reconstruction, as well two Ottoman intrusive burials for temporal and cultural comparison. All analyzed individuals exhibited δ13C and δ15N values consistent with a diet based heavily on C3 terrestrial sources. There is no statistically significant difference between the isotopic compositions of the two sexes, though males appear to show larger variations compared to females. Interesting patterns in the isotopic compositions of the subadults suggested weaning children may be fed with supplements with distinctive δ13C values. Significant difference in sulfur isotope values between humans and fauna could be the earliest evidence of transhumance and could identify one older adult male as a possible transhumant shepherd. Both Ottoman individuals had distinctively different δ13C, δ15N, and δ34S values compared to the Neolithic individuals. This is the first large scale analysis of human stable isotopes from the eastern end of the early Holocene Fertile Crescent. It provides a baseline for future intersite exploration of stable isotopes and insight into the lifeways, health, and processes of neolithisation associated with the origins of goat domestication at Ganj Dareh and the surrounding Central Zagros.
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Wagner, D. S., C. J. Markworth, C. D. Wagner, et al. "Ratio encoding combinatorial libraries with stable isotopes and their utility in pharmaceutical research." Combinatorial Chemistry & High Throughput Screening 1, no. 3 (1998): 143–53. http://dx.doi.org/10.2174/138620730103220120142733.
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Combinatorial libraries are an important tool for lead discovery in the pharmaceutical industry. Advances in high throughput screening coupled with combinatorial chemistry can significantly reduce the time to find lead compounds. A major difficulty in developing large combinatorial libraries is the ability to identify active compounds. This paper describes a rapid and sensitive encoding/decoding methodology that utilizes stable isotopes and mass spectrometry. The ability of mass spectrometry to precisely determine the intensity of isotopic abundances provides a unique encoding strategy employing synthetically generated ratios of stable isotopes in a compound as the code. The application of ratio encoding is demonstrated using peptoid and imidazole chemistries. Supporting data demonstrate that the incorporation of one or more stable isotopes using unique-predetermined ratios can encode chemical libraries. In addition, the presence of a unique isotopic pattern in a ligand can facilitate the pharmacokinetic analysis. Isotope incorporation into a compound and subsequently into its metabolites reliably distinguishes products from other molecules in the mass spectrum. This is illustrated by metabolic analyses of peptoid and imidazole compounds.
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Hu, Yue, Guo-dong Liu, and Cheng-cheng Xia. "Multi-time scale analysis of hydrogen and oxygen isotope characteristics and influence factors in precipitation in Vienna." MATEC Web of Conferences 246 (2018): 02011. http://dx.doi.org/10.1051/matecconf/201824602011.
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Based on isotope and meteorology data at Vienna station from 1972 to 2014 provided by GNIP, the average monthly and annual hydrogen and oxygen stable isotopic compositions and main factors were analyzed by using various trend analysis, periodic analysis and correlation analysis methods. The monthly mean isotopic compositions change slightly, reflecting the fact that although Vienna is affected by the maritime climate and the continental climate, the former impact is more significant. The slope and intercept of the LMWL in Vienna changed significantly from October to March, indicating that it was affected by alternating effects of the two climates. The annual mean isotopes show a trend of enrichment, and it has an obvious temperature effect, but the rainfall amount effect does not exist, and no simple linear relationship was found between isotopes and vapor pressure. The annual mean isotopes also show the periodic variation characteristics with scales such as 9-16 years and 18~29 years, and it is concluded that the isotope values will be enriched after 2011 at the scale 22 years. The multivariate regression relationship established by δD and δ18O with three climate parameters of temperature, precipitation and vapor pressure can quantitatively estimate the missing value in isotopic data.
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Balcaen, A., E. Claeys, V. Fievez, P. Boeckx, O. van Cleemput, and S. de Smet. "Stable carbon isotope analysis of faecal and blood samples of sheep in relation to the diet." Proceedings of the British Society of Animal Science 2003 (2003): 159. http://dx.doi.org/10.1017/s1752756200013181.
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Stable isotopes have been extraordinarily helpful in understanding animal migration, diet, food webs and nutrient flow (Hilderbrand et al., 1996), based on the property that C3 and C4 plants possess distinctly different 13C/12C ratios (δ13C value) due to isotopic fractionation during photosynthetic carbon fixation (Smith & Epstein, 1971). Most woody species and temperate graminoids assimilate carbon via the Calvin cycle (C3), which discriminates stronger against the heavier isotope (13C) than Hatch-Slack (C4) species (tropical and subtropical graminoids and some shrubs). C3 and C4 plant species have mean δ13C values of -27 ‰ and -13 ‰ respectively (O’Leary, 1981). DeNiro & Epstein (1978) were one of the first to show that the isotopic composition of the whole animal body is similar to that of its diet. Other authors have also found relationships between the isotopic composition of animal tissues and the diet (González-Martin et al., 1999; Jones et al., 1979). The aim of this study was to investigate stable carbon isotope composition in sheep fed diets consisting of either C3 or C3+C4 plants.
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Jung, Hyejung, Dong-Chan Koh, Yun Kim, Sung-Wook Jeen, and Jeonghoon Lee. "Stable Isotopes of Water and Nitrate for the Identification of Groundwater Flowpaths: A Review." Water 12, no. 1 (2020): 138. http://dx.doi.org/10.3390/w12010138.
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Nitrate contamination in stream water and groundwater is a serious environmental problem that arises in areas of high agricultural activities or high population density. It is therefore important to identify the source and flowpath of nitrate in water bodies. In recent decades, the dual isotope analysis (δ15N and δ18O) of nitrate has been widely applied to track contamination sources by taking advantage of the difference in nitrogen and oxygen isotope ratios for different sources. However, transformation processes of nitrogen compounds can change the isotopic composition of nitrate due to the various redox processes in the environment, which often makes it difficult to identify contaminant sources. To compensate for this, the stable water isotope of the H2O itself can be used to interpret the complex hydrological and hydrochemical processes for the movement of nitrate contaminants. Therefore, the present study aims at understanding the fundamental background of stable water and nitrate isotope analysis, including isotope fractionation, analytical methods such as nitrate concentration from samples, instrumentation, and the typical ranges of δ15N and δ18O from various nitrate sources. In addition, we discuss hydrograph separation using the oxygen and hydrogen isotopes of water in combination with the nitrogen and oxygen isotopes of nitrate to understand the relative contributions of precipitation and groundwater to stream water. This study will assist in understanding the groundwater flowpaths as well as tracking the sources of nitrate contamination using the stable isotope analysis in combination with nitrate and water.
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Pecquerie, Laure, Roger M. Nisbet, Ronan Fablet, Anne Lorrain, and Sebastiaan A. L. M. Kooijman. "The impact of metabolism on stable isotope dynamics: a theoretical framework." Philosophical Transactions of the Royal Society B: Biological Sciences 365, no. 1557 (2010): 3455–68. http://dx.doi.org/10.1098/rstb.2010.0097.
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Stable isotope analysis is a powerful tool used for reconstructing individual life histories, identifying food-web structures and tracking flow of elemental matter through ecosystems. The mechanisms determining isotopic incorporation rates and discrimination factors are, however, poorly understood which hinders a reliable interpretation of field data when no experimental data are available. Here, we extend dynamic energy budget (DEB) theory with a limited set of new assumptions and rules in order to study the impact of metabolism on stable isotope dynamics in a mechanistic way. We calculate fluxes of stable isotopes within an organism by following fluxes of molecules involved in a limited number of macrochemical reactions: assimilation, growth but also structure turnover that is here explicitly treated. Two mechanisms are involved in the discrimination of isotopes: (i) selection of molecules occurs at the partitioning of assimilation, growth and turnover into anabolic and catabolic sub-fluxes and (ii) reshuffling of atoms occurs during transformations. Such a framework allows for isotopic routing which is known as a key, but poorly studied, mechanism. As DEB theory specifies the impact of environmental conditions and individual state on molecule fluxes, we discuss how scenario analysis within this framework could help reveal common mechanisms across taxa.
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Ruiz-Cooley, R. I., Unai Markaida, D. Gendron, and S. Aguíñiga. "Stable isotopes in jumbo squid (Dosidicus gigas) beaks to estimate its trophic position: comparison between stomach contents and stable isotopes." Journal of the Marine Biological Association of the United Kingdom 86, no. 2 (2006): 437–45. http://dx.doi.org/10.1017/s0025315406013324.
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Stomach contents and carbon (C) and nitrogen (N) stable isotope analysis were used to evaluate trophic relationships of jumbo squid, Dosidicus gigas. Buccal masses, beaks and stomach contents of large and medium maturing-sized jumbo squid and muscle from its main prey, the myctophid Benthosema panamense, were collected in the Gulf of California, Mexico during 1996, 1997 and 1999. Both the quantified C and N-isotope ratios in muscle, and stomach content analysis revealed that larger-sized maturing squid showed a higher trophic position than medium-sized individuals. However, a discrepancy between stomach contents versus stable isotope analyses was found in evaluating trophic relationships. Simple dilution models as a function of growth were used to estimate the C and N renewal dietary shift for jumbo squid. Estimates of the initial C and N pools in D. gigas with an initial age of 70 days and 210 days indicated isotopic shifts of 32% after a threefold biomass increase and 25% after a fourfold biomass increase, respectively. Additionally, beak samples of jumbo squid were evaluated as an alternative tissue to estimate squid trophic position using stable isotopes. The results showed a significant correlation between stable isotope ratios from muscle and beak samples. Muscle isotope values were higher than beak by 1% and 4% for δ13C and δ15N respectively. A test with jumbo squid beaks collected from a stomach of a stranded sperm whale confirmed the viability of this method.
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Uriarte, Amaya, Alberto García, Aurelio Ortega, Fernando De la Gándara, José Quintanilla, and Raúl Laiz-Carrión. "Isotopic discrimination factors and nitrogen turnover rates in reared Atlantic bluefin tuna larvae (Thunnus thynnus): effects of maternal transmission." Scientia Marina 80, no. 4 (2016): 447. http://dx.doi.org/10.3989/scimar.04435.25a.
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The use of stable isotope analysis to study animal diets requires estimates of isotopic turnover rates (half time, t50) and discrimination factors (Δ) for an accurate interpretation of trophic patterns. The stable isotopes of carbon and nitrogen were analysed for eggs and reared larvae of Thunnus thynnus, as well as for the different diets supplied during the experiment. The results showed high values of δ15N in eggs and larvae (n=646) until 4 DAH. After this time lapse, the stable isotope values declined progressively until 12 DAH, when notochord flexion began. The δ13C showed an inverse trend, suggesting that maternal inheritance of the stable isotopes is evident until pre-flexion stages. This study proposes a model for estimating maternal isotopic signatures of bluefin broodstock. After notochord flexion, larvae were fed with aquaculture-bred gilthead seabream, which resulted in a rapid increase of bluefin larvae δ15N values together with a rapid decrease in δ13C values. The estimated nitrogen half-time to reach the steady state from the diet was 2.5±0.3 days and the discrimination factor was 0.4±0.3(‰). These results represent the first data set that has allowed isotopic nitrogen turnover rates and discrimination factors of the larval stages of bluefin tuna to be estimated.
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Andhihutomo, Rismah Taufik, Satrio Satrio, Rasi Prasetio та Agus Budhie Wijatna. "Studi Interaksi Air Tanah Dangkal dan Air Sungai di Sepanjang Daerah Aliran Kali Garang Semarang Menggunakan Isotop Stabil δ18O dan δ2H". EKSPLORIUM 38, № 1 (2017): 43. http://dx.doi.org/10.17146/eksplorium.2017.38.1.3247.
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ABSTRAKPenelitian mengenai interaksi airtanah dangkal dengan air sungai Kali Garang di Semarang, Jawa Tengah, menggunakan parameter isotop 18O dan 2H telah dilakukan. Sebanyak 16 sampel air tanah dangkal dan 3 sampel air sungai diambil untuk analisis kandungan isotop stabil d18O dan d2H menggunakan alat Liquid Water Isotope Analyzer LGR DLT-100. Hasil analisis memperlihatkan adanya dua asal daerah masukan air: daerah pertama memiliki kandungan isotop d18O antara -9,41 ‰ hingga-8,5 ‰ dan d2H antara -58,2 ‰ hingga -51,6 ‰; daerah kedua memiliki kandungan isotop d18O dan d2H masing-masing -7,15 ‰ dan -41,55 ‰. Dengan demikian, hasil tersebut mengindikasikan bahwa sampel-sampel air pertama berasal dari elevasi yang relatif lebih tinggi jika dibandingkan dengan asal sampel air kedua, namun keduanya tidak mengalami interaksi dengan air sungai. Sedangkan sampel air tanah lainnya menunjukkan bahwa satu sampel (R4) memiliki interelasi berupa pencampuran dengan air sungai dan dua sampel lainnya (L1 dan R1) mengalami pencampuran dengan air asin atau air laut. ABSTRACTA study related to shallow groundwater interaction with Kali Garang River water in Semarang, Central Java using stable isotopes of 18O and 2H has been conducted. As much as 16 groundwater and 3 river water samples were taken for stable isotopes d18O and d2H analysis using Liquid water isotope analyzer LGR DLT-100. The results of analysis shows that there are two area of water recharge origin: the first area contains d18O isotope ranging between -9.41 ‰ to -8.5 ‰ and d2H between -58.2 ‰ to -51.6 ‰; the second area contains isotopes of d18O and d2H -7.15 and -41.55 ‰, respectively. Thus, these results indicate that the first water samples originate from a higher elevation than the origin of the second water sample, but both of them have no interrelation with river water. Whereas, other groundwater samples show that the sample (R4) has interrelation (i.e. mixing) with the river water and two other samples (L1 and R1) have interrelation with salty water or seawater.
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Jeon, Jihyeon, Hojin Lee, Minsu Lee, et al. "Comparative Analysis of Water Isotopic Compositions: Evaluating Isotope Analyzer for Soil and Extraction Method for Stem Water." Forests 15, no. 3 (2024): 420. http://dx.doi.org/10.3390/f15030420.
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Stable isotopes of water (δ2H and δ18O) are reliable tracers for the investigation of plant–soil–water interactions in forest ecosystems. However, variations in isotopic compositions may arise due to differences in analytical instruments and water extraction methods. In this study, we conducted three different experiments to identify isotopic differences caused by analytical and methodological variations. First, we analyzed soil water by using the two most commonly applied methods: isotope ratio mass spectrometry (IRMS) and cavity ring-down spectroscopy (CRDS). Second, we compared the isotopes in xylem water extracted from the stems of nine tree species using cryogenic vacuum distillation (CVD) with different heating times. Third, we compared the compositions in xylem water extracted with three different methods: mechanical squeezing using a pressure chamber (PC), an induction module (IM), and CVD. The differences in isotopic composition between IRMS and CRDS were significant but minimal. Soil properties were not significant factors contributing to differences between the two instruments. For the xylem water extraction with CVD, each of the nine tree species required heating for more than three hours. Significant differences were observed in δ2H among the three extraction methods for xylem water. Xylem water extracted by CVD showed more depleted values compared to those obtained by PC and IM. Our results highlight the importance of considering analytical and methodological variations in stable isotope analysis.
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Kim, Songyi, Yeongcheol Han, Soon Do Hur, Kei Yoshimura, and Jeonghoon Lee. "Relating Moisture Transport to Stable Water Vapor Isotopic Variations of Ambient Wintertime along the Western Coast of Korea." Atmosphere 10, no. 12 (2019): 806. http://dx.doi.org/10.3390/atmos10120806.
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Atmospheric water vapor transfers energy, causes meteorological phenomena and can be modified by climate change in the western coast region of Korea. In Korea, previous studies have utilized precipitation isotopic compositions in the water cycle for correlations with climate variables, but there are few studies using water vapor isotopes. In this study, water vapor was directly collected by a cryogenic method, analyzed for its isotopic compositions, and used to trace the origin and history of water vapor in the western coastal region of Korea during the winter of 2015/2016. Our analysis of paired mixing ratios with water vapor isotopes can explain the mechanism of water vapor isotopic fractionation and the extent of the mixing of two different air masses. We confirm the correlation between water vapor isotopes and meteorological parameters such as temperature, relative humidity, and specific humidity. The main water vapor in winter was derived from the continental polar region of northern Asia and showed an enrichment of 10 per mil (δ18O) through the evaporation of the Yellow Sea. Our results demonstrate the utility of using ground-based isotope observations as a complementary resource for constraining isotope-enabled Global Circulation Model in future investigations of atmospheric water cycles. These measurements are expected to support climate studies (speleothem) in the west coast region of Korea.
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Curtis, JS, MA Albins, EB Peebles, and CD Stallings. "Stable isotope analysis of eye lenses from invasive lionfish yields record of resource use." Marine Ecology Progress Series 637 (March 5, 2020): 181–94. http://dx.doi.org/10.3354/meps13247.
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Patterns of stable isotopes recorded in metabolically stable, serially synthesized, structures such as eye lenses can yield robust descriptions of resource use across the life histories of individual fish. We performed stable isotope analysis of eye lenses sampled from invasive lionfishes Pterois spp. and a potentially competitive native mesopredator, the graysby Cephalopholis cruentata, to compare lifelong patterns of trophic resource use on a coral reef ledge in Biscayne National Park, Florida, USA. In both lionfishes and graysby, stable isotope values increased logarithmically with eye-lens radius, likely reflecting increases in trophic position with growth. Tissue samples toward the interior of the lens were the most isotopically similar between lionfish and graysby, suggesting interspecific resource use overlap may be strongest in smaller fish. We observed substantial variation in isotopic chronologies around the underlying logarithmic trend within individual fish, potentially driven by patterns of movement across measured environmental isotopic gradients, intraspecific variation in resource use specificity, or other ecological variables of interest. These results are the first to describe patterns of size-structured resource use across the life of individual lionfish, an important objective for researchers studying the interactions of this highly invasive species with the surrounding ecological communities. Additionally, through this example, we illustrate analytical approaches and considerations for the application of eye-lens stable isotope analysis to the study of vertebrate ecology.
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Alexander, Stuart A., Keith A. Hobson, Cheri L. Gratto-Trevor, and Antony W. Diamond. "Conventional and isotopic determinations of shorebird diets at an inland stopover: the importance of invertebrates and Potamogeton pectinatus tubers." Canadian Journal of Zoology 74, no. 6 (1996): 1057–68. http://dx.doi.org/10.1139/z96-117.
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We used gut-content and stable-isotope techniques to determine diets of shorebirds staging at a prairie wetland complex. Stable-isotope ratios for carbon (13C/12C) and nitrogen (15N/14N) varied greatly within and among prey types and shorebirds, depending on location within the complex. Both dietary techniques suggested that Long-billed Dowitchers (Limnodromus scolopaceus) and Stilt Sandpipers (Calidris himantopus) ate mostly invertebrates, whereas Hudsonian (Limosa haemastica) and Marbled godwits (Limosa fedoa) ate mainly Potamogeton pectinatus tubers. In comparison, the stable-isotope technique indicated that godwits, especially juvenile Marbled Godwits, ate more invertebrates than is indicated by the gut-content analysis. The discrepancies between methods reflect the potential for bias in the application of these techniques. Researchers using stable isotopes to assess migratory shorebird diets should be aware of possible complications arising from isotopic variability within prey types, even over small geographic ranges. High isotopic variability at inland agro-wetland complexes might preclude reliable isotopic assessment of shorebird diets, especially long term. Rhizivory in godwits may be more common than is generally recognized, especially at inland stopovers during autumn migration in both North America and Eurasia, and should be factored into conservation initiatives for these species.
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Bühler, Janica C., Josefine Axelsson, Franziska A. Lechleitner, et al. "Investigating stable oxygen and carbon isotopic variability in speleothem records over the last millennium using multiple isotope-enabled climate models." Climate of the Past 18, no. 7 (2022): 1625–54. http://dx.doi.org/10.5194/cp-18-1625-2022.
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Abstract. The incorporation of water isotopologues into the hydrology of general circulation models (GCMs) facilitates the comparison between modeled and measured proxy data in paleoclimate archives. However, the variability and drivers of measured and modeled water isotopologues, as well as the diversity of their representation in different models, are not well constrained. Improving our understanding of this variability in past and present climates will help to better constrain future climate change projections and decrease their range of uncertainty. Speleothems are a precisely datable terrestrial paleoclimate archives and provide well-preserved (semi-)continuous multivariate isotope time series in the lower latitudes and mid-latitudes and are therefore well suited to assess climate and isotope variability on decadal and longer timescales. However, the relationships of speleothem oxygen and carbon isotopes to climate variables are influenced by site-specific parameters, and their comparison to GCMs is not always straightforward. Here we compare speleothem oxygen and carbon isotopic signatures from the Speleothem Isotopes Synthesis and Analysis database version 2 (SISALv2) to the output of five different water-isotope-enabled GCMs (ECHAM5-wiso, GISS-E2-R, iCESM, iHadCM3, and isoGSM) over the last millennium (850–1850 CE). We systematically evaluate differences and commonalities between the standardized model simulation outputs. The goal is to distinguish climatic drivers of variability for modeled isotopes and compare them to those of measured isotopes. We find strong regional differences in the oxygen isotope signatures between models that can partly be attributed to differences in modeled surface temperature. At low latitudes, precipitation amount is the dominant driver for stable water isotope variability; however, at cave locations the agreement between modeled temperature variability is higher than for precipitation variability. While modeled isotopic signatures at cave locations exhibited extreme events coinciding with changes in volcanic and solar forcing, such fingerprints are not apparent in the speleothem isotopes. This may be attributed to the lower temporal resolution of speleothem records compared to the events that are to be detected. Using spectral analysis, we can show that all models underestimate decadal and longer variability compared to speleothems (albeit to varying extents). We found that no model excels in all analyzed comparisons, although some perform better than the others in either mean or variability. Therefore, we advise a multi-model approach whenever comparing proxy data to modeled data. Considering karst and cave internal processes, e.g., through isotope-enabled karst models, may alter the variability in speleothem isotopes and play an important role in determining the most appropriate model. By exploring new ways of analyzing the relationship between the oxygen and carbon isotopes, their variability, and co-variability across timescales, we provide methods that may serve as a baseline for future studies with different models using, e.g., different isotopes, different climate archives, or different time periods.
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Liu, Jiaxin. "Analysis of Variation Characteristics and Driving Factors of Precipitation Isotopes in the Monsoon Region of Offshore China—A Case Study of Hong Kong." E3S Web of Conferences 438 (2023): 01008. http://dx.doi.org/10.1051/e3sconf/202343801008.
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To explore the isotopic composition of precipitation in the monsoon region of offshore China, this paper takes Hong Kong, China as the study area. Based on the Global Network of Isotope in Precipitation (GNIP), the data about hydrogen and oxygen stable isotopes in the precipitation of Hong Kong from 1961 to 2022 were collected, from which its time variation trend was obtained via linear regression. Further, the distribution characteristics and influencing factors of hydrogen and oxygen stable isotopes in the precipitation of Hong Kong were analyzed. According to the results, the precipitation isotopes and d-excess in Hong Kong have no significant inter-annual variability. The seasonal variation of precipitation isotope and d-excess is monthly apparent, both of which are lower in the rainy season and higher in the dry season. In addition, the seasonal periodicity of isotope and d-excess proves that the main source of precipitation is marine water vapor, and the source of water vapor controlling precipitation in Hong Kong remains stable as a whole. The global meteoric water line in Hong Kong is δD=8.17δ18O+11.82, which is very close to the global one. Meanwhile, δ18O in precipitation is negatively correlated with the temperature, precipitation, and water vapor pressure. As the main driving force to control its isotope variation, precipitation conceals the effect of temperature. Taking Hong Kong as an example, the above research reveals some characteristics of monsoon regions in offshore China, which is of positive significance for further investigating the influencing factors of the hydrologic cycle and isotope change at regional and local scales in the future.
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Guo, Rong, Shengjie Wang, Mingjun Zhang, et al. "Stable Hydrogen and Oxygen Isotope Characteristics of Bottled Water in China: A Consideration of Water Source." Water 11, no. 5 (2019): 1065. http://dx.doi.org/10.3390/w11051065.
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The origin of bottled water can be identified via its stable isotope signature because of the spatial variation of the stable isotope composition of natural waters. In this paper, the spatial pattern of δ2H and δ18O values were analyzed for a total of 242 bottled water samples produced at 137 sites across China that were randomly purchased during 2014–2015. The isotopic ratios of bottled water vary between −166‰ and −19‰ for δ2H, and between −21.6‰ and −2.1‰ for δ18O. Based on multiple regression analyses using meteorological and geographical parameters, an isoscape of Chinese bottled water was created. The results showed that altitude among spatial parameters and precipitation amount and air temperature among meteorological parameters were major natural factors determining the isotopic variation of bottled water. Our findings indicate the potential and the significance of the use of stable isotopes for the source identification of bottled water. An analysis of different origin types (spring, glacier and unmarked) and several different brands of bottled water in the same location reflected different production processes and source signatures.
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McNicol, Gavin, Zhongjie Yu, Z. Carter Berry, Nathan Emery, Fiona M. Soper, and Wendy H. Yang. "Tracing plant–environment interactions from organismal to planetary scales using stable isotopes: a mini review." Emerging Topics in Life Sciences 5, no. 2 (2021): 301–16. http://dx.doi.org/10.1042/etls20200277.
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Natural isotope variation forms a mosaic of isotopically distinct pools across the biosphere and flows between pools integrate plant ecology with global biogeochemical cycling. Carbon, nitrogen, and water isotopic ratios (among others) can be measured in plant tissues, at root and foliar interfaces, and in adjacent atmospheric, water, and soil environments. Natural abundance isotopes provide ecological insight to complement and enhance biogeochemical research, such as understanding the physiological conditions during photosynthetic assimilation (e.g. water stress) or the contribution of unusual plant water or nutrient sources (e.g. fog, foliar deposition). While foundational concepts and methods have endured through four decades of research, technological improvements that enable measurement at fine spatiotemporal scales, of multiple isotopes, and of isotopomers, are advancing the field of stable isotope ecology. For example, isotope studies now benefit from the maturation of field-portable infrared spectroscopy, which allows the exploration of plant–environment sensitivity at physiological timescales. Isotope ecology is also benefiting from, and contributing to, new understanding of the plant–soil–atmosphere system, such as improving the representation of soil carbon pools and turnover in land surface models. At larger Earth-system scales, a maturing global coverage of isotope data and new data from site networks offer exciting synthesis opportunities to merge the insights of single-or multi-isotope analysis with ecosystem and remote sensing data in a data-driven modeling framework, to create geospatial isotope products essential for studies of global environmental change.
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Lesser, Michael P., Marc Slattery, and Keir J. Macartney. "Using Stable Isotope Analyses to Assess the Trophic Ecology of Scleractinian Corals." Oceans 3, no. 4 (2022): 527–45. http://dx.doi.org/10.3390/oceans3040035.
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Studies on the trophic ecology of scleractinian corals often include stable isotope analyses of tissue and symbiont carbon and nitrogen. These approaches have provided critical insights into the trophic sources and sinks that are essential to understanding larger-scale carbon and nitrogen budgets on coral reefs. While stable isotopes have identified most shallow water (<30 m) corals as mixotrophic, with variable dependencies on autotrophic versus heterotrophic resources, corals in the mesophotic zone (~30–150 m) transition to heterotrophy with increasing depth because of decreased photosynthetic productivity. Recently, these interpretations of the stable isotope data to distinguish between autotrophy and heterotrophy have been criticized because they are confounded by increased nutrients, reverse translocation of photosynthate, and changes in irradiance that do not influence photosynthate translocation. Here we critically examine the studies that support these criticisms and show that they are contextually not relevant to interpreting the transition to heterotrophy in corals from shallow to mesophotic depths. Additionally, new data and a re-analysis of previously published data show that additional information (e.g., skeletal isotopic analysis) improves the interpretation of bulk stable isotope data in determining when a transition from primary dependence on autotrophy to heterotrophy occurs in scleractinian corals.
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Hobson, Keith A., Robert B. Brua, William L. Hohman, and Len I. Wassenaar. "Low Frequency of “Double Molt” of Remiges in Ruddy Ducks Revealed by Stable Isotopes: Implications for Tracking Migratory Waterfowl." Auk 117, no. 1 (2000): 129–35. http://dx.doi.org/10.1093/auk/117.1.129.
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Abstract Ratios of the stable carbon (δ13C) and hydrogen (δD) isotopes in newly grown remiges of Ruddy Ducks (Oxyura jamaicensis) are influenced by the isotopic character of food types and ambient water. Systematic isotopic foodweb and water differences between coastal wintering grounds and prairie breeding grounds of Ruddy Ducks provide the basis for using isotopic analyses of feathers to trace the location and timing of molt. Anecdotal evidence, based largely on captive birds, suggests that Ruddy Ducks replace their remiges twice each year (once each on the breeding and wintering grounds), but a recent literature analysis indicates that this phenomenon is rare. Thus, we investigated the extent to which a biannual molt of the remiges occurs in the wild and at the population level. We analyzed the stable isotopes of carbon (n = 57 birds) and hydrogen (n = 50 birds) in flight feathers to estimate the prevalence of the so-called “double molt” of remiges in free-living Ruddy Ducks. Our data showed that natural populations of Ruddy Ducks express an overwhelming unimodal distribution of isotope ratios in their remiges, suggesting that they undergo a single molt at or near the breeding grounds. Only 3 to 6 of 50 birds from Manitoba showed isotopic evidence consistent with growing remiges on the wintering grounds. Feathers from Ruddy Ducks harvested during the fall in the Mississippi Flyway had isotopic profiles consistent with growth on northern freshwater breeding sites. Thus, our results confirm that the replacement of remiges twice each year by Ruddy Ducks is rare, and they suggest that this dual stable-isotope technique can be used to infer general molting origins of North American waterfowl.
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Ebert, Claire E., Asta J. Rand, Kirsten Green-Mink, et al. "Sulfur isotopes as a proxy for human diet and mobility from the preclassic through colonial periods in the Eastern Maya lowlands." PLOS ONE 16, no. 8 (2021): e0254992. http://dx.doi.org/10.1371/journal.pone.0254992.
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Maya archaeologists have long been interested in understanding ancient diets because they provide information about broad-scale economic and societal transformations. Though paleodietary studies have primarily relied on stable carbon (δ13C) and nitrogen (δ15N) isotopic analyses of human bone collagen to document the types of food people consumed, stable sulfur (δ34S) isotope analysis can potentially provide valuable data to identify terrestrial, freshwater, or marine/coastal food sources, as well as determine human mobility and migration patterns. Here we assess applications of δ34S for investigating Maya diet and migration through stable isotope analyses of human bone collagen (δ13C, δ15N, and δ34S) from 114 individuals from 12 sites in the Eastern Maya lowlands, temporally spanning from the Late Preclassic (300 BCE—300 CE) through Colonial periods (1520–1800 CE). Results document a diet dominated by maize and other terrestrial resources, consistent with expectations for this inland region. Because δ34S values reflect local geology, our analyses also identified recent migrants to the Eastern lowlands who had non-local δ34S signatures. When combined with other indicators of mobility (e.g., strontium isotopes), sulfur isotopic data provide a powerful tool to investigate movement across a person’s lifespan. This study represents the largest examination of archaeological human δ34S isotope values for the Maya lowlands and provides a foundation for novel insights into both subsistence practices and migration.
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Eltsova, Liubov Sergeevna, Olga Vasilyevna Duryagina, Liudmila Victorovna Kuznetsova та Elena Sergeevna Ivanova. "Isotopic composition of carbon (ẟ¹³C) and nitrogen (ẟ¹⁵N) in the hair of the order Rodentia of the Vologda Region". Samara Journal of Science 13, № 4 (2024): 20–25. https://doi.org/10.55355/snv2024134103.
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The study is devoted to the analysis of the ratio of stable carbon isotopes (ẟ¹³C) and stable nitrogen isotopes (ẟ¹⁵N) in the hair of mammals of the Rodentia order (Eurasian beaver –Castor fiberLinnaeus, 1758; Ural field mouse –Apodemus uralensisPallas, 1811; European water vole –Arvicola amphibius(Linnaeus, 1758); Muskrat –Ondatra zibethicusLinnaeus, 1766; Siberian chipmunk –Eutamias sibiricus(Laxmann, 1769); Siberian flying squirrel –Pteromys volansLinnaeus, 1758; Red squirrel –Sciurus vulgarisLinnaeus, 1758) in the Vologda Region.The isotopic composition of carbon in the hair of the studied animals varies from −28,2‰ to −17,9‰, nitrogen – from 0,4‰ to 10,6‰. The values of ẟ¹³C in the hair of mammals of the Rodentia order are higher, and ẟ¹⁵N is lower than in the hair of mammals of the Carnivora order, previously studied in the Vologda Region. The ratio of heavy carbon and nitrogen isotopes in the hair of animals captured in different regions of the Vologda Region does not differ significantly statistically. Ithas been establishedthat the hair of aquatic organisms is less enriched in heavy carbon isotope and more enriched in heavy nitrogen isotope than the hair of terrestrial representatives of the Rodentia order. The hair of omnivoresis more enrichedin a heavy nitrogen isotope than the hair of herbivores. The overlap of isotopic niches in certain species of the Rodentia orderhas been revealed. A statistically significant decrease in the δ¹³C content in Muskrat hair by 2,7‰ over 50 years has been established.
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Kravchenko, Kseniia A., Linn S. Lehnert, Anton S. Vlaschenko, and Christian C. Voigt. "Multiple isotope tracers in fur keratin discriminate between mothers and offspring." Rapid Communications in Mass Spectrometry 33, no. 10 (2019): 907–13. https://doi.org/10.5281/zenodo.13447220.
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(Uploaded by Plazi for the Bat Literature Project) Methods: During the post‐lactation period, we collected fur of juvenile and female common noctule bats (Nyctalus noctula) from the same maternity roost. Using a combination of elemental analysis and stable isotope ratio mass spectrometry, we measured the hydrogen, carbon and nitrogen isotope ratios in fur keratin. The hydrogen isotope ratios were measured for the non‐exchangeable portion of hydrogen in keratin. The derived isotopic niches and isoscape origin models were compared between mothers and juveniles. Results: The fur keratin of juveniles was enriched by 1.6‰ in 15N and depleted by 2.9‰ in 13C compared with that of the mothers. In addition, the hydrogen isotope ratios were 13.4‰ lower in the fur keratin of juveniles than in that of mothers. The estimated isotopic niches of nursing females and juveniles were not overlapping and differed in size. Overall, the isoscape origin models projected juveniles as being from a more northern origin than the mothers; yet both models suggested the study site as a likely place of origin. Conclusions: Our results suggest that isotope ratio data of juvenile bats should not be used for transfer functions in isoscape origin models because of isotopic routing and discrimination during lactation. Not accounting for age effects may increase the inaccuracy of geographical assignments in mammals when based on stable hydrogen isotopes.
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Kravchenko, Kseniia A., Linn S. Lehnert, Anton S. Vlaschenko, and Christian C. Voigt. "Multiple isotope tracers in fur keratin discriminate between mothers and offspring." Rapid Communications in Mass Spectrometry 33, no. 10 (2019): 907–13. https://doi.org/10.5281/zenodo.13447220.
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(Uploaded by Plazi for the Bat Literature Project) Methods: During the post‐lactation period, we collected fur of juvenile and female common noctule bats (Nyctalus noctula) from the same maternity roost. Using a combination of elemental analysis and stable isotope ratio mass spectrometry, we measured the hydrogen, carbon and nitrogen isotope ratios in fur keratin. The hydrogen isotope ratios were measured for the non‐exchangeable portion of hydrogen in keratin. The derived isotopic niches and isoscape origin models were compared between mothers and juveniles. Results: The fur keratin of juveniles was enriched by 1.6‰ in 15N and depleted by 2.9‰ in 13C compared with that of the mothers. In addition, the hydrogen isotope ratios were 13.4‰ lower in the fur keratin of juveniles than in that of mothers. The estimated isotopic niches of nursing females and juveniles were not overlapping and differed in size. Overall, the isoscape origin models projected juveniles as being from a more northern origin than the mothers; yet both models suggested the study site as a likely place of origin. Conclusions: Our results suggest that isotope ratio data of juvenile bats should not be used for transfer functions in isoscape origin models because of isotopic routing and discrimination during lactation. Not accounting for age effects may increase the inaccuracy of geographical assignments in mammals when based on stable hydrogen isotopes.
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Kravchenko, Kseniia A., Linn S. Lehnert, Anton S. Vlaschenko, and Christian C. Voigt. "Multiple isotope tracers in fur keratin discriminate between mothers and offspring." Rapid Communications in Mass Spectrometry 33, no. 10 (2019): 907–13. https://doi.org/10.5281/zenodo.13447220.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Methods: During the post‐lactation period, we collected fur of juvenile and female common noctule bats (Nyctalus noctula) from the same maternity roost. Using a combination of elemental analysis and stable isotope ratio mass spectrometry, we measured the hydrogen, carbon and nitrogen isotope ratios in fur keratin. The hydrogen isotope ratios were measured for the non‐exchangeable portion of hydrogen in keratin. The derived isotopic niches and isoscape origin models were compared between mothers and juveniles. Results: The fur keratin of juveniles was enriched by 1.6‰ in 15N and depleted by 2.9‰ in 13C compared with that of the mothers. In addition, the hydrogen isotope ratios were 13.4‰ lower in the fur keratin of juveniles than in that of mothers. The estimated isotopic niches of nursing females and juveniles were not overlapping and differed in size. Overall, the isoscape origin models projected juveniles as being from a more northern origin than the mothers; yet both models suggested the study site as a likely place of origin. Conclusions: Our results suggest that isotope ratio data of juvenile bats should not be used for transfer functions in isoscape origin models because of isotopic routing and discrimination during lactation. Not accounting for age effects may increase the inaccuracy of geographical assignments in mammals when based on stable hydrogen isotopes.
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Kravchenko, Kseniia A., Linn S. Lehnert, Anton S. Vlaschenko, and Christian C. Voigt. "Multiple isotope tracers in fur keratin discriminate between mothers and offspring." Rapid Communications in Mass Spectrometry 33, no. 10 (2019): 907–13. https://doi.org/10.5281/zenodo.13447220.
Full textAbstract:
(Uploaded by Plazi for the Bat Literature Project) Methods: During the post‐lactation period, we collected fur of juvenile and female common noctule bats (Nyctalus noctula) from the same maternity roost. Using a combination of elemental analysis and stable isotope ratio mass spectrometry, we measured the hydrogen, carbon and nitrogen isotope ratios in fur keratin. The hydrogen isotope ratios were measured for the non‐exchangeable portion of hydrogen in keratin. The derived isotopic niches and isoscape origin models were compared between mothers and juveniles. Results: The fur keratin of juveniles was enriched by 1.6‰ in 15N and depleted by 2.9‰ in 13C compared with that of the mothers. In addition, the hydrogen isotope ratios were 13.4‰ lower in the fur keratin of juveniles than in that of mothers. The estimated isotopic niches of nursing females and juveniles were not overlapping and differed in size. Overall, the isoscape origin models projected juveniles as being from a more northern origin than the mothers; yet both models suggested the study site as a likely place of origin. Conclusions: Our results suggest that isotope ratio data of juvenile bats should not be used for transfer functions in isoscape origin models because of isotopic routing and discrimination during lactation. Not accounting for age effects may increase the inaccuracy of geographical assignments in mammals when based on stable hydrogen isotopes.
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Roncone, Alberto, and Luana Bontempo. "Stable Isotope Analysis of Alcoholic Beverages: A Review." Beverages 11, no. 3 (2025): 89. https://doi.org/10.3390/beverages11030089.
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Alcoholic beverages represent a sector of significant economic and cultural importance but are also susceptible to fraud and adulteration, which can compromise their quality and authenticity. Isotopic analyses have become increasingly valuable tools for tracing the geographical origin and ensuring the quality control of products such as wine, beer, and distilled spirits. This literature review examines the main isotopic analysis techniques employed in this field, including Isotope Ratio Mass Spectrometry (IRMS) and Site-Specific Natural Isotope Fractionation by Nuclear Magnetic Resonance (SNIF-NMR), with a particular focus on the insights derived from the isotopic ratios of various elements, notably δ(2H), δ(13C), δ(18O), δ(15N) and δ(34S).
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Sehrawat, Jagmahender Singh, and Jaspreet Kaur. "Role of stable isotope analyses in reconstructing past life-histories and the provenancing human skeletal remains: a review." Anthropological Review 80, no. 3 (2017): 243–58. http://dx.doi.org/10.1515/anre-2017-0017.
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AbstractThis article reviews the present scenario of use of stable isotopes (mainly δ13C, δ15N, δ18O,87Sr) to trace past life behaviours like breast feeding and weaning practices, the geographic origin, migration history, paleodiet and subsistence patterns of past populations from the chemical signatures of isotopes imprinted in human skeletal remains. This approach is based on the state that food-web isotopic signatures are seen in the human bones and teeth and such signatures can change parallely with a variety of biogeochemical processes. By measuring δ13C and δ15N isotopic values of subadult tissues of different ages, the level of breast milk ingestion at particular ages and the components of the complementary foods can be assessed. Strontium and oxygen isotopic analyses have been used for determining the geographic origins and reconstructing the way of life of past populations as these isotopes can map the isotopic outline of the area from where the person acquired water and food during initial lifetime. The isotopic values of strontium and oxygen values are considered specific to geographical areas and serve as reliable chemical signatures of migration history of past human populations (local or non-local to the site). Previous isotopic studies show that the subsistence patterns of the past human populations underwent extensive changes from nomadic to complete agricultural dependence strategies. The carbon and nitrogen isotopic values of local fauna of any archaeological site can be used to elucidate the prominence of freshwater resources in the diet of the past human populations found near the site. More extensive research covering isotopic descriptions of various prehistoric, historic and modern populations is needed to explore the role of stable isotope analysis for provenancing human skeletal remains and assessing human migration patterns/routes, geographic origins, paleodiet and subsistence practices of past populations.
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Stavropoulou, Vasiliki, Anastasia Pyrgaki, Eleni Zagana, Christos Pouliaris, and Nerantzis Kazakis. "The Contributions of Tectonics, Hydrochemistry and Stable Isotopes to the Water Resource Management of a Thermal–Mineral Aquifer: The Case Study of Kyllini, Northwest Peloponnese." Geosciences 14, no. 8 (2024): 205. http://dx.doi.org/10.3390/geosciences14080205.
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This study aims to investigate the intricate relationship between geological structures, water chemistry, and isotopic composition in order to gain a deeper understanding of the origins and recharge mechanisms of thermal–mineral waters in the Kyllini region. The research integrates tectonic analysis, hydrochemical data, and stable isotope measurements to delineate recharge zones and trace the origin of these unique water sources. The methods used for delineation are the geological and tectonic study of the area, as well as hydrochemical and isotopic data analysis. The findings highlight that tectonic activity creates preferential flow paths and consequently influences the hydrogeological framework, facilitating deep circulation and the upwelling of thermal waters. Monthly analyses of groundwater samples from the Kyllini thermal spring were conducted over one hydrological year (2019–2020) and compared with data from the area collected in 2009. The hydrochemical profiles of major and minor ions reveal distinct signatures corresponding to various water–rock interactions, while stable isotope analysis provides insights into the climatic conditions and altitudes of recharge areas. Hydrochemical analyses reveal the composition of thermal–mineral waters, aiding in the identification of potential sources and their evolution. The conceptualization of Kyllini contributes to the deeper understanding of the intricate interplay between tectonics, hydrochemistry, and stable isotopes. During a hydrological year, the water type of Kyllini’s spring groundwater remains the same (Na-Cl-HCO3), presenting only slight alterations.
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Weng, Yongbiao, Aina Johannessen, and Harald Sodemann. "High-resolution stable isotope signature of a land-falling atmospheric river in southern Norway." Weather and Climate Dynamics 2, no. 3 (2021): 713–37. http://dx.doi.org/10.5194/wcd-2-713-2021.
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Abstract. Heavy precipitation at the west coast of Norway is often connected to elongated meridional structures of high integrated water vapour transport known as atmospheric rivers (ARs). Here we present high-resolution measurements of stable isotopes in near-surface water vapour and precipitation during a land-falling AR in southwestern Norway on 7 December 2016. In our analysis, we aim to identify the influences of moisture source conditions, weather system characteristics, and post-condensation processes on the isotope signal in near-surface water vapour and precipitation. A total of 71 precipitation samples were collected during the 24 h sampling period, mostly taken at sampling intervals of 10–20 min. The isotope composition of near-surface vapour was continuously monitored in situ with a cavity ring-down spectrometer. Local meteorological conditions were in addition observed from a vertical pointing rain radar, a laser disdrometer, and automatic weather stations. We observe a stretched, “W”-shaped evolution of isotope composition during the event. Combining paired precipitation and vapour isotopes with meteorological observations, we define four different stages of the event. The two most depleted periods in the isotope δ values are associated with frontal transitions, namely a combination of two warm fronts that follow each other within a few hours and an upper-level cold front. The d-excess shows a single maximum and a step-wise decline in precipitation and a gradual decrease in near-surface vapour. Thereby, the isotopic evolution of the near-surface vapour closely follows that of the precipitation with a time delay of about 30 min, except for the first stage of the event. Analysis using an isotopic below-cloud exchange framework shows that the initial period of low and even negative d-excess in precipitation was caused by evaporation below cloud base. The isotope signal from the cloud level became apparent at ground level after a transition period that lasted up to several hours. Moisture source diagnostics for the periods when the cloud signal dominates show that the moisture source conditions are then partly reflected in surface precipitation and water vapour isotopes. In our study, the isotope signal in surface precipitation during the AR event reflects the combined influence of atmospheric dynamics, moisture sources, and atmospheric distillation, as well as cloud microphysics and below-cloud processes. Based on this finding, we recommend careful interpretation of results obtained from Rayleigh distillation models in such events, in particular for the interpretation of surface vapour and precipitation from stratiform clouds.
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Wahl, Sonja, Benjamin Walter, Franziska Aemisegger, Luca Bianchi, and Michael Lehning. "Identifying airborne snow metamorphism with stable water isotopes." Cryosphere 18, no. 9 (2024): 4493–515. http://dx.doi.org/10.5194/tc-18-4493-2024.
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Abstract. Wind-blown snow is a frequent phenomenon in high-elevation and polar regions which impacts the surface energy and mass balance of these areas. Loose surface snow gets eroded and transported by wind, which influences the snow particles' physical properties (size, shape, optical properties) that determine the characteristics of the emerging wind-impacted snowpack layer. During airborne snow transport, the governing processes happen on the micro-scale while the particles are transported over long distances. The unfolding processes and the evolution of the particles' physical properties are thus difficult to observe in situ. Here, we used cold-laboratory ring wind tunnel experiments as an interim solution to study the governing processes during airborne snow transport with stable water isotopes as tracers for these micro-scale processes. Repeated analysis of airborne-sampled snow by micro-computed tomography (µCT) documented a growing and rounding of snow particles with transport time, with a concurrent decrease in specific surface area. Stable water isotope analysis of airborne snow and water vapour allowed us to attribute this evolution to the process of airborne snow metamorphism. The changes observed in the snow isotopic composition showed a clear isotopic signature of metamorphic deposition, which requires particle–air temperature gradients. These results question the validity of the thermal-equilibrium assumption between particles and air inside the saltation layer of wind-blown snow events, where the conditions are similar to the ones found in the wind tunnel. Our results thus refine the understanding of the governing processes in the saltation layer and suggest that the snow's isotopic composition can inform on local wind-blown snow events as the original snow isotope signal gets overprinted by airborne snow metamorphism. Within transport times of 3 h, we observed changes in the isotope signal of airborne snow of up to +1.47 ‰ in δ18O, ±5.7 ‰ in δD, and −6.1 ‰ in d-excess. Thus, airborne snow metamorphism has the potential to influence the climate signal stored in snow and ice core stable water isotope records.
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Böhlke, J. K. "Variation in the terrestrial isotopic composition and atomic weight of argon (IUPAC Technical Report)." Pure and Applied Chemistry 86, no. 9 (2014): 1421–32. http://dx.doi.org/10.1515/pac-2013-0918.
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AbstractThe isotopic composition and atomic weight of argon (Ar) are variable in terrestrial materials. Those variations are a source of uncertainty in the assignment of standard properties for Ar, but they provide useful information in many areas of science. Variations in the stable isotopic composition and atomic weight of Ar are caused by several different processes, including (1) isotope production from other elements by radioactive decay (radiogenic isotopes) or other nuclear transformations (e.g., nucleogenic isotopes), and (2) isotopic fractionation by physical-chemical processes such as diffusion or phase equilibria. Physical-chemical processes cause correlated mass-dependent variations in the Ar isotope-amount ratios (40Ar/36Ar, 38Ar/36Ar), whereas nuclear transformation processes cause non-mass-dependent variations. While atmospheric Ar can serve as an abundant and homogeneous isotopic reference, deviations from the atmospheric isotopic ratios in other Ar occurrences limit the precision with which a standard atomic weight can be given for Ar. Published data indicate variation of Ar atomic weights in normal terrestrial materials between about 39.7931 and 39.9624. The upper bound of this interval is given by the atomic mass of 40Ar, as some samples contain almost pure radiogenic 40Ar. The lower bound is derived from analyses of pitchblende (uranium mineral) containing large amounts of nucleogenic 36Ar and 38Ar. Within this interval, measurements of different isotope ratios (40Ar/36Ar or 38Ar/36Ar) at various levels of precision are widely used for studies in geochronology, water–rock interaction, atmospheric evolution, and other fields.
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Kelleway, J. J., S. M. Trevathan-Tackett, J. Baldock, and L. P. Critchley. "Plant litter composition and stable isotope signatures vary during decomposition in blue carbon ecosystems." Biogeochemistry 158, no. 2 (2022): 147–65. http://dx.doi.org/10.1007/s10533-022-00890-3.
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AbstractThe ratio of isotopes of carbon (13C:12C or δ13C) and nitrogen (15N:14N or δ15N) are common indicators of the flow and storage of organic matter in coastal wetland research. Effective use of these indicators requires quantification and understanding of: (1) the variability of isotope signatures of potential organic matter source materials; and (2) the influence of organic matter decomposition on isotopic signatures. While it is well-established that organic matter characteristics change during the decomposition process, there has been little direct quantification of any concurrent shifts in isotope signatures for coastal detritus. In this study, we addressed this by quantifying: (1) shifts in sample composition using solid-state 13C Nuclear Magnetic Resonance (NMR) spectroscopy; and (2) shifts in δ13C and δ15N signatures of coastal plant tissues from field litterbag experiments. We observed significant shifts in 13C NMR spectra across the course of deployment for all four plant tissues assessed (leaves of mangrove Avicennia marina; branchlets of supratidal tree Casuarina glauca; leaf wrack and roots/rhizomes of the seagrass Zostera muelleri), driven largely by the preferential loss of labile constituents and concentration of more resistant macromolecules, such as lignin and leaf waxes. While there were shifts in isotope ratios for all species, these varied in direction and magnitude among species, tissue type and isotopes. This included δ13C enrichments of up to 3.1‰ and 2.4‰ in leaves of A. marina, and branchlets of C. glauca, respectively, but δ13C depletions of up to 4.0‰ for Z. muelleri. Shifts in δ15N varied among species and tissue types, with few clear temporal patterns. Partial least squares regression analyses showed that some tissue isotope signatures can be reliably predicted on the basis of sample composition (13C NMR spectra), however, multiple inter- and intra-species variations preclude a simple explanation of isotopic signature shifts on the basis of plant-material molecular shifts alone. Further, we cannot preclude the potential influence of microbe-associated organic matter on sample composition or isotopic signatures. Our findings emphasise the importance of considering decomposition effects on stable isotope signatures in blue carbon ecosystems. Isotope approaches will remain a valuable tool in coastal ecosystem research, but require robust experimental approaches (including appropriate use of decomposed end-members or fractionation correction factors; quantification of microbial organic matter) and quantification of decomposition dynamics for specific plant tissues and environmental settings.
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Behrmann-Godel, J., and E. Yohannes. "Multiple isotope analyses of the pike tapeworm Triaenophorus nodulosus reveal peculiarities in consumer–diet discrimination patterns." Journal of Helminthology 89, no. 2 (2014): 238–43. http://dx.doi.org/10.1017/s0022149x13000849.
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AbstractPrevious studies of dietary isotope discrimination have led to the general expectation that a consumer will exhibit enriched stable isotope levels relative to its diet. Parasite–host systems are specific consumer–diet pairs in which the consumer (parasite) feeds exclusively on one dietary source: host tissue. However, the small numbers of studies previously carried out on isotopic discrimination in parasite–host (ΔXP-HT) systems have yielded controversial results, showing some parasites to be isotopically depleted relative to their food source, while others are enriched or in equilibrium with their hosts. Although the mechanism for these deviations from expectations remains to be understood, possible influences of specific feeding niche or selection for only a few nutritional components by the parasite are discussed. ΔXP-HT for multiple isotopes (δ13C, δ15N, δ34S) were measured in the pike tapeworm Triaenophorus nodulosus and two of its life-cycle fish hosts, perch Perca fluviatilis and pike Esox lucius, within which T. nodulosus occupies different feeding locations. Variability in the value of ΔXP-HT calculated for the parasite and its different hosts indicates an influence of feeding location on isotopic discrimination. In perch liver ΔXP-HT was relatively more negative for all three stable isotopes. In pike gut ΔXP-HT was more positive for δ13C, as expected in conventional consumer–diet systems. For parasites feeding on pike gut, however, the δ15N and δ34S isotope values were comparable with those of the host. We discuss potential causes of these deviations from expectations, including the effect of specific parasite feeding niches, and conclude that ΔXP-HT should be critically evaluated for trophic interactions between parasite and host before general patterns are assumed.
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Pike, Scott. "Characterization of Intra-Quarry Variability in Pentelic Marble Using Stable Isotopes: A Case Study of the Parthenon." Minerals 15, no. 3 (2025): 231. https://doi.org/10.3390/min15030231.
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This study presents a systematic analysis of stable isotopes (δ13C and δ18O) in Pentelic marble from the ancient quarries of Mount Pentelikon, Greece. A total of 610 samples were collected from 83 quarry pits, including all identified ancient extraction sites, to build a comprehensive reference database. Of those, stable isotope ratios of carbon and oxygen were measured for 384 samples. The results reveal significant variability in stable isotope values across different quarry regions, challenging the assumption of isotopic homogeneity in Pentelic marble. Notably, distinct δ13C and δ18O patterns allow differentiation between quarry areas and specific extraction zones. These findings provide a more refined isotopic framework for provenance studies of ancient artifacts. Application of the new database suggests that marble for the Parthenon’s West Pediment was sourced from the northern upslope quarries in Aspra Marmara, whereas structural elements of the Parthenon were extracted from the lower Spilia Divail quarry, as well as other pits across the ancient quarry zone. The results demonstrate that multiple quarry pits from both the lower slope and upper slope quarries were exploited for the construction of the Parthenon. This research highlights the benefits of extensive sampling and stable isotope analysis in identifying quarry sources, emphasizing the value of undertaking detailed and thorough field surveys and sampling programs to gain new perspectives into ancient resource use.
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Carrizo, Daniel, Maria Unger, Henry Holmstrand, et al. "Compound-specific bromine isotope compositions of one natural and six industrially synthesised organobromine substances." Environmental Chemistry 8, no. 2 (2011): 127. http://dx.doi.org/10.1071/en10090.
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Environmental contextBrominated organic compounds of both natural and anthropogenic origin are commonly found in the environment. Bromine has two stable isotopes and the isotopic composition of brominated compounds may vary depending on production pathways and degradation processes. These variations are a result of isotope fractionation effects, when heavy isotopes react slower than lighter isotopes. We apply compound-specific bromine isotope analysis to industrial brominated organic compounds, and one naturally produced analogue, to test the feasibility of the technique to investigate the source and environmental fate of these compounds. AbstractThe stable bromine isotopic composition (δ81Br) was determined for six industrially synthesised brominated organic compounds (BOCs) and one natural BOC by gas-chromatography multi-collector inductively coupled plasma mass spectrometry (GC-mcICP-MS). The δ81Br compositions of brominated benzenes, phenols (both natural and industrial), anisoles, and naphthalenes were constrained with the standard differential measurement approach using as reference a monobromobenzene sample with an independently determined δ81Br value (–0.39‰ v. Standard Mean Ocean Bromide, SMOB). The δ81Br values for the industrial BOCs ranged from –4.3 to –0.4‰. The average δ81Br value for the natural compound (2,4-dibromophenol) was 0.2 ± 1.6‰ (1 s.d.), and for the identical industrial compound (2,4-dibromophenol) –1.1 ± 0.9‰ (1 s.d.), with a statistically significant difference of ~1.4 (P < 0.05). The δ81Br of four out of six industrial compounds was found to be significantly different from that of the natural sample. These novel results establish the bromine isotopic variability among the industrially produced BOCs in relation to a natural sample.
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Alderton, David H. M. "Oxygen isotope fractionation between cassiterite and water." Mineralogical Magazine 53, no. 371 (1989): 373–76. http://dx.doi.org/10.1180/minmag.1989.053.371.13.
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Analysis of stable isotopes in coexisting minerals has found wide application in the study of hydrothermal mineral deposits, particularly for elucidating the temperature and source of the fluid phase involved in mineralisation. For these purposes the temperature dependence of isotopic fractionation in several mineral-water systems has already been established (e.g. Friedman and O'Neil, 1977; O'Neil, 1986). Unfortunately, the oxygen isotope fractionation between cassiterite (SnO2) and water has not been adequately characterized, and this has hindered a full utilization of oxygen isotope data derived from studies of tin deposits (e.g. Harzer, 1970; Patterson et al., 1981; Kelly and Rye, 1979). Because of this situation, an attempt is made here to derive a relationship between temperature and the fractionation of oxygen isotopes (Δ) between quartz and cassiterite, based on the fractionations observed in naturally-occurring assemblages and independent temperature estimates.
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Krasnova, Elizaveta A., Anna Yu Yurchenko, Anton G. Kalmykov, and Maria M. Fomina. "Isotopic-geochemical peculiarities of distribution of gas hydrocarbons in the Bazhenov formation section (South part of the Western Siberia)." Georesursy 21, no. 2 (2019): 153–58. http://dx.doi.org/10.18599/grs.2019.2.153-158.
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In this work we describe the distribution of stable carbon isotopes in hydrocarbon gases from four wells located in the southern and central parts of the Western Siberia. The main goal was to understand the influence of the lithological composition and geological settings on isotopic composition of gases and their formation. Two genetically different groups of hydrocarbon gases were identified based on the author’s research, as well as analysis of archival and literature materials on the isotope composition of hydrocarbons. We estimated the close relationship between the main factors of the migration, degree of metamorphism of organic matter and the isotope composition of hydrocarbon gases produced by the Bazhenov formation.
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Gagnon, Chantal, and Keith A. Hobson. "Using stable isotopes to track frugivory in migratory passerines." Canadian Journal of Zoology 87, no. 11 (2009): 981–92. http://dx.doi.org/10.1139/z09-086.
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Several species of North American migratory songbirds undergo seasonal diet shifts from insects to fruits, but this phenomenon is poorly quantified. Measurement of naturally occurring stable isotopes of carbon (δ13C) and nitrogen (δ15N) are linked to sources of diets and trophic level, respectively. We used stable carbon (δ13C) and nitrogen (δ15N) isotope analyses of blood and claw tissues of 16 species of migratory songbirds to evaluate the timing and extent of frugivory over different periods. Species differed considerably in their tissue δ15N values, but we found poor isotopic segregation of species according to our a priori classifications as insectivores or omnivores. Season accounted for considerable variance in tissue δ15N values. However, only American Robin ( Turdus migratorius L., 1766), Northern Oriole ( Icterus galbula (L., 1758)), Gray Catbird ( Dumetella carolinensis (L., 1766)), Least Flycatcher ( Empidonax minimus (W.M. Baird and S.F. Baird, 1843)), and Warbling Vireo ( Vireo gilvus (Vieillot, 1808)) showed expected decrease in winter-grown tissue δ15N values compared with those grown in late summer. This indicates either that our a priori guild associations were incorrect and (or) that using stable isotopes to track frugivory at continental scales is problematic. We recommend that the isotope technique be used to track frugivory only in well-constrained systems where food-web δ15N follows reliable and understood trophic enrichment patterns.
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Heydarizad, Mojtaba, Luis Gimeno, Masoud Minaei, and Marjan Shahsavan Gharehghouni. "Stable Isotope Signatures in Tehran’s Precipitation: Insights from Artificial Neural Networks, Stepwise Regression, Wavelet Coherence, and Ensemble Machine Learning Approaches." Water 15, no. 13 (2023): 2357. http://dx.doi.org/10.3390/w15132357.
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This study investigates the impact of precipitation on Middle Eastern countries like Iran using precise methods such as stable isotope techniques. Stable isotope data for precipitation in Tehran were obtained from the Global Network of Isotopes in Precipitation (GNIP) station and sampled for two periods: 1961–1987 and 2000–2004. Precipitation samples were collected, stored, and shipped to a laboratory for stable isotope analyses using the GNIP procedure. Several models, including artificial neural networks (ANNs), stepwise regression, and ensemble machine learning approaches, were applied to simulate stable isotope signatures in precipitation. Among the studied machine learning models, XGboost showed the most accurate simulation with higher R2 (0.84 and 0.86) and lower RMSE (1.97 and 12.54), NSE (0.83 and 0.85), AIC (517.44 and 965.57), and BIC values (531.42 and 979.55) for 18O and 2H compared to other models, respectively. The uncertainty in the simulations of the XGboost model was assessed using the bootstrap technique, indicating that this model accurately predicted stable isotope values. Various wavelet coherence analyses were applied to study the associations between stable isotope signatures and their controlling parameters. The BWC analysis results show coherence relationships, mainly ranging from 16 to 32 months for both δ18O–temperature and δ2H–temperature pairs with the highest average wavelet coherence (AWC). Temperature is the dominant predictor influencing stable isotope signatures of precipitation, while precipitation has lower impacts. This study provides valuable insights into the relationship between stable isotopes and climatological parameters of precipitation in Tehran.
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Basov, Alexander, Liliya Fedulova, Ekaterina Vasilevskaya, and Stepan Dzhimak. "Possible Mechanisms of Biological Effects Observed in Living Systems during 2H/1H Isotope Fractionation and Deuterium Interactions with Other Biogenic Isotopes." Molecules 24, no. 22 (2019): 4101. http://dx.doi.org/10.3390/molecules24224101.
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This article presents the original descriptions of some recent physics mechanisms (based on the thermodynamic, kinetic, and quantum tunnel effects) providing stable 2H/1H isotope fractionation, leading to the accumulation of particular isotopic forms in intra- or intercellular space, including the molecular effects of deuterium interaction with 18O/17O/16O, 15N/14N, 13C/12C, and other stable biogenic isotopes. These effects were observed mainly at the organelle (mitochondria) and cell levels. A new hypothesis for heavy nonradioactive isotope fractionation in living systems via neutron effect realization is discussed. The comparative analysis of some experimental studies results revealed the following observation: “Isotopic shock” is highly probable and is observed mostly when chemical bonds form between atoms with a summary odd number of neutrons (i.e., bonds with a non-compensated neutron, which correspond to the following equation: Nn − Np = 2k + 1, where k ϵ Z, k is the integer, Z is the set of non-negative integers, Nn is number of neutrons, and Np is number of protons of each individual atom, or in pair of isotopes with a chemical bond). Data on the efficacy and metabolic pathways of the therapy also considered 2H-modified drinking and diet for some diseases, such as Alzheimer’s disease, Friedreich’s ataxia, mitochondrial disorders, diabetes, cerebral hypoxia, Parkinson’s disease, and brain cancer.
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Kelsey, Eric P., Cameron P. Wake, Kaplan Yalcin, and Karl Kreutz. "Eclipse Ice Core Accumulation and Stable Isotope Variability as an Indicator of North Pacific Climate." Journal of Climate 25, no. 18 (2012): 6426–40. http://dx.doi.org/10.1175/jcli-d-11-00389.1.
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Abstract The high accumulation rate and negligible amount of melt at Eclipse Icefield (3017 m) in the Saint Elias Range of Yukon, Canada, allows for the preservation of a high-resolution isotopic and glaciochemical records valuable for reconstruction of climatic variables. Each of the three Eclipse ice cores have a well-constrained depth–age scale with dozens of reference horizons over the twentieth century that permits an exceptional level of confidence in the results of the current calibration exercise. Stacked time series of accumulation and stable isotopes were divided into cold and warm seasons and seasons of extreme high and extreme low accumulation and stable isotope values (eight groups). For each group, season-averaged composites of 500-hPa geopotential height grids, and the individual seasons that constitute them, were analyzed to elucidate common anomalous flow patterns. This analysis shows that the most fractionated isotopes and lowest accumulation cold seasons reflect a more zonal height pattern in the North Pacific associated with negative Pacific–North American (PNA) and Pacific decadal oscillation (PDO) indices. Conversely, the least fractionated isotopes and highest accumulation cold seasons are associated with a positive PNA pattern. Although only a maximum of approximately 20% of the total number of accumulation and stable isotope seasons exhibit a relatively consistent relationship with 500-hPa geopotential height patterns, these results support the hypothesis that the most extreme accumulation and extreme isotope cold-season values in the Saint Elias Mountains are related to consistent atmospheric circulation and oceanic sea surface temperature patterns.