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Orlowski, N., P. Kraft y L. Breuer. "Exploring water cycle dynamics through sampling multitude stable water isotope pools in a small developed landscape of Germany". Hydrology and Earth System Sciences Discussions 12, n.º 2 (6 de febrero de 2015): 1809–53. http://dx.doi.org/10.5194/hessd-12-1809-2015.
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Abstract. Conducting a dual stable water isotope (δ2H and δ18O) study in the developed landscape of the Schwingbach catchment (Germany) helped to unravel connectivity and disconnectivity between the different water cycle components. The two-year weekly to biweekly measurements of precipitation, stream, and groundwater isotopes revealed that surface and groundwater are decoupled from the annual precipitation cycle but showed bidirectional interactions between each other. Seasonal variations based on temperature effects were observed in the precipitation signal but neither reflected in stream nor in groundwater isotopic signatures. Apparently, snowmelt played a fundamental role for groundwater recharge explaining the observed differences to precipitation δ-values. A spatially distributed snapshot sampling of soil water isotopes in two soil depths at 52 sampling points across different land uses (arable land, forest, and grassland) revealed that top soil isotopic signatures were similar to the precipitation input signal. Preferential water flow paths occurred under forested soils explaining the isotopic similarities between top and subsoil isotopic signatures. Due to human-impacted agricultural land use (tilling and compression) of arable and grassland soils, water delivery to the deeper soil layers was reduced, resulting in significant different isotopic signatures. However, the land use influence smoothed out with depth and soil water approached groundwater δ-values. Seasonally tracing stable water isotopes through soil profiles showed that the influence of new percolating soil water decreased with depth as no remarkable seasonality in soil isotopic signatures was obvious at depth > 0.9 m and constant values were observed through space and time. Little variation in individual isotope time series of stream and groundwater restricted the use of classical isotope hydrology techniques e.g. mean transit time estimation or hydrograph separation. Still, tracing stable water isotopes through the water cycle was valuable for determining interactions between different water cycle components and gaining catchment specific process understanding in a developed, human-impacted landscape.
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Sare, David T. J., John S. Millar y Frederick J. Longstaffe. "Tracing dietary protein in red-backed voles (Clethrionomys gapperi) using stable isotopes of nitrogen and carbon". Canadian Journal of Zoology 83, n.º 5 (1 de mayo de 2005): 717–25. http://dx.doi.org/10.1139/z05-064.
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We examined the stable isotopes of nitrogen and carbon in a small mammal, the red-backed vole (Clethroinomys gapperi (Vigors, 1830)), to determine if isotope signatures reflect diet composition. Nitrogen- and carbon-isotope ratios in tissues from voles maintained on different protein levels in the laboratory were compared with wild-trapped voles. The isotopic fractionation of dietary nitrogen and carbon was also examined as food was digested in the stomach, incorporated into bone collagen, bioapatite, and hair, and excreted as feces. Nitrogen and carbon isotopes were fractionated differently depending on the isotopic composition and protein content of the diet. δ15N and δ13C values appear to be influenced by factors in addition to diet, such as macronutrients metabolized for respiration, metabolic rate, and periods of protein shortage.
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Orlowski, Natalie, Philipp Kraft, Jakob Pferdmenges y Lutz Breuer. "Exploring water cycle dynamics by sampling multiple stable water isotope pools in a developed landscape in Germany". Hydrology and Earth System Sciences 20, n.º 9 (20 de septiembre de 2016): 3873–94. http://dx.doi.org/10.5194/hess-20-3873-2016.
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Abstract. A dual stable water isotope (δ2H and δ18O) study was conducted in the developed (managed) landscape of the Schwingbach catchment (Germany). The 2-year weekly to biweekly measurements of precipitation, stream, and groundwater isotopes revealed that surface and groundwater are isotopically disconnected from the annual precipitation cycle but showed bidirectional interactions between each other. Apparently, snowmelt played a fundamental role for groundwater recharge explaining the observed differences to precipitation δ values. A spatially distributed snapshot sampling of soil water isotopes at two soil depths at 52 sampling points across different land uses (arable land, forest, and grassland) revealed that topsoil isotopic signatures were similar to the precipitation input signal. Preferential water flow paths occurred under forested soils, explaining the isotopic similarities between top- and subsoil isotopic signatures. Due to human-impacted agricultural land use (tilling and compression) of arable and grassland soils, water delivery to the deeper soil layers was reduced, resulting in significant different isotopic signatures. However, the land use influence became less pronounced with depth and soil water approached groundwater δ values. Seasonally tracing stable water isotopes through soil profiles showed that the influence of new percolating soil water decreased with depth as no remarkable seasonality in soil isotopic signatures was obvious at depths > 0.9 m and constant values were observed through space and time. Since classic isotope evaluation methods such as transfer-function-based mean transit time calculations did not provide a good fit between the observed and calculated data, we established a hydrological model to estimate spatially distributed groundwater ages and flow directions within the Vollnkirchener Bach subcatchment. Our model revealed that complex age dynamics exist within the subcatchment and that much of the runoff must has been stored for much longer than event water (average water age is 16 years). Tracing stable water isotopes through the water cycle in combination with our hydrological model was valuable for determining interactions between different water cycle components and unravelling age dynamics within the study area. This knowledge can further improve catchment-specific process understanding of developed, human-impacted landscapes.
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Mazariegos, Junior G., Jennifer C. Walker, Xiaomei Xu y Claudia I. Czimczik. "Tracing Artificially Recharged Groundwater using Water and Carbon Isotopes". Radiocarbon 59, n.º 2 (11 de agosto de 2016): 407–21. http://dx.doi.org/10.1017/rdc.2016.51.
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AbstractWe conducted an isotopic analysis of groundwater in Orange County, California, USA, around the Talbert Seawater Injection Barrier to determine if recycled water, used to artificially recharge local aquifers, carries a unique isotopic signature that can be used as a tracer. From September 2014 to April 2015, we collected groundwater from six privately owned wells within the coastal groundwater basin, along with various surface waters. All water samples were analyzed for their stable isotopic composition (δ18O, δD), the δ13C and 14C signature of the dissolved inorganic carbon (DIC) pool, DIC concentration, pH, and salinity. The DIC of groundwater mixing with recycled water is enriched in 14C above natural background levels, with varying signal strength through time, depleted in δ13C, and low in DIC concentration. Water isotopes further suggest that recycled water is a mixture of Colorado River water and regional groundwater. In contrast, groundwater found further away from the injection barrier has carbon and water isotope composition consistent with regional groundwater and Santa Ana River water. Our findings imply that recycled water injected through the Talbert Barrier is isotopically unique, and that 14C enrichment may be used as an intrinsic tracer of artificial recharge within the basin.
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Gulson, Brian y Herbert Wong. "Stable Isotopic Tracing—A Way Forward for Nanotechnology". Environmental Health Perspectives 114, n.º 10 (octubre de 2006): 1486–88. http://dx.doi.org/10.1289/ehp.9277.
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Zhang, Mengnan, Xiaoqian Li, Xuxue Cheng, Xinfeng Wang, Mian Song, Xiaoyan Wang y Xuemei Ma. "Isotopic Tracing of Perchlorate Sources in the Environment". Journal of Chemistry 2021 (18 de octubre de 2021): 1–10. http://dx.doi.org/10.1155/2021/9978489.
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Perchlorate (ClO4−) is an emerging persistent pollutant that is ubiquitous in the environment at trace concentrations. Perchlorate ingestion poses a risk to human health because it interferes with thyroidal hormone production. The identification of perchlorate sources in groundwater is a primary concern. Chlorine and multi-oxygen isotopic tracing of perchlorate (δ37Cl, 36Cl/Cl, δ18O, and Δ17O) can provide a unique tool for identifying the origin and transport of perchlorate in groundwater. Along with the kinetic fractionation of chlorine and oxygen isotopes, the Δ17O value, 36Cl/Cl ratio, and ε18O/ε37Cl (the fractionation coefficient of oxygen and chlorine isotopes) are constant, potentially indicating the biodegradation of perchlorate, without disguising its source information. Therefore, comprehensive characterization of stable chlorine and poly-oxygen isotopes is expected to provide direct evidence for identifying the source of perchlorate in groundwater. However, further studies are needed to increase the amount of isotopic data of different perchlorate sources, to make the end-member model available to broader regions. It is critically important to understand the range of values and differences of isotopes among natural perchlorate sources and the perchlorate formation mechanisms.
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McNicol, Gavin, Zhongjie Yu, Z. Carter Berry, Nathan Emery, Fiona M. Soper y Wendy H. Yang. "Tracing plant–environment interactions from organismal to planetary scales using stable isotopes: a mini review". Emerging Topics in Life Sciences 5, n.º 2 (26 de febrero de 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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El Shami, Mohamad, Milan Savani, Lauren Gattie, William Hicks, Timothy Richardson, Samuel McBrayer y Kalil Abdullah. "TMET-28. A METHOD FOR EX VIVO STABLE ISOTOPE TRACING IN SURGICALLY EXPLANTED GLIOMA ORGANOIDS". Neuro-Oncology 24, Supplement_7 (1 de noviembre de 2022): vii267—vii268. http://dx.doi.org/10.1093/neuonc/noac209.1033.
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Abstract Stable isotope tracing is a powerful method for elucidating tumor metabolism. While in vivo stable isotope tracing is one of the most faithful approaches for studying metabolic activity under pathophysiologically relevant conditions, this method is technically challenging and costly to perform. We therefore sought to optimize an ex vivo stable isotope tracing approach under conditions that recapitulate the in vivo tumor microenvironment (TME), focusing on three key features: cellular heterogeneity, nutrient availability, and oxygenation. Surgically eXplanted Organoids (SXOs) are 3-dimensional glioma models that retain the diverse cell populations in human brain tumors. We tested whether glioma SXOs can be cultured in Human Plasma-Like Medium (HPLM) under brain-relevant oxygen levels (5%) for the purpose of stable isotope tracing. We cultured SXOs in conventional media, HPLM for 24 hours, or HPLM for 120 hours under 5% oxygen. We observed no significant differences in markers of tumor architecture, cellular proliferation rates, or stemness profiles. We then performed stable isotope tracing in SXOs cultured in HLPM at 5% oxygen. We acclimated SXOs to HPLM for 24 hours or 120 hours before replacing media with either HPLM (unlabeled) or HPLM with 15N2 glutamine (labeled). 15N isotopic labeling patterns in various metabolites were compared between the 24- and 120-hour conditions by linear regression. These patterns were strongly concordant over time (r2 = 0.9544), indicating that steady-state metabolic fluxes are stable in these cultures. We then analyzed intermediates that occupy key nodes in amino acid metabolism, redox homeostasis, and nucleotide synthesis pathways and found similarly strong concordance between labeling patterns at the individual metabolite level. Our findings outline an effective approach for conducting ex vivo stable isotope tracing in heterocellular glioma models under conditions that mimic the TME. This approach may complement and enhance analogous in vivo methods to provide new insights into glioma metabolism.
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Fiket, Željka, Martina Furdek Turk, Maja Ivanić y Goran Kniewald. "Non-traditional stable isotope signatures in geological matrices as a tool for interpreting environmental changes – a review". Geologia Croatica 74, n.º 2 (30 de junio de 2021): 177–87. http://dx.doi.org/10.4154/gc.2021.12.
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The development of new analytical techniques enabled the precise determination of the expanded set of stable isotopes and provided new insight into existing geological issues. This review outlines recent studies of non-traditional isotope signatures in geological matrices, summarizing in one place, new data for the stable isotopes of Ca, Mg, Sr, Li, Ni, Cr, and Cu and their application in the interpretation of environmental processes. Although some, such as δ44Ca and δ26Mg, have previously been used to track changes in seawater chemistry throughout geological history, recent studies report their application as geochemical proxies of post-depositional processes. Similarly, isotopic signatures of strontium, previously used in radioactive isotope chronology, and δ7Li, used in tracing plate subduction and crust/mantle material cycling, found a new application in studies of weathering patterns. The use of δ53Cr and δ 65Cu isotope signatures, on the other hand, reflects their fractionation under different redox conditions, whereas δ60Ni, due to its adsorption and co-precipitation with sulfide species and Fe-Mn phases, is used in interpreting the contributions of different material sources. And while the isotopic signatures of all these elements indicate certain environmental conditions and processes (e.g. post-depositional processes, redox conditions, organic matter input, the contribution of sources, etc.), by combining them a more comprehensive insight into the investigated environment can be achieved.
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Banda, Limbikani C., Michael O. Rivett, Anold S. K. Zavison, Sydney Kamtukule y Robert M. Kalin. "National Stable Isotope Baseline for Precipitation in Malawi to Underpin Integrated Water Resources Management". Water 13, n.º 14 (13 de julio de 2021): 1927. http://dx.doi.org/10.3390/w13141927.
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With the resurgence of water-isotope tracing applications for Integrated Water Resource Management in developing countries, establishing a stable isotopic baseline is necessary. Developing countries, including Malawi, continue to struggle with the generation of consistent and long-term isotopic datasets due to non-existent or inadequate in-country water-isotope capacity. Malawi has made significant advances in its quest to establish a stable isotopic baseline through the establishment of the Malawi Network of Isotope in Precipitation. This study provides the first results for the isotopic characterization of precipitation in Malawi with a view to reinforcing understanding of the country’s hydrological cycle. Error-in-variables regression defined a Local Meteoric Water Line as δ2H = 8.0 (±0.3) δ18O + 13.0 (±2.0) using stable isotopic records of 37 monthly samples from 5 stations between 2014 and 2019. Local precipitation (isotopic composition) is consistent with global precipitation expectations, its condensation-forming process occurring under equilibrium conditions and a higher intercept (d-excess) above the 10‰ for Global Meteoric Water Line, implying that air moisture recycling significantly influences local precipitation. Wider variations observed in local precipitation isotopic signatures are largely attributed to different moisture-bearing systems and diverse geographic factors across the country. Additional stations are recommended to improve spatial coverage that, together with longer temporal records, may help understanding and resolving uncertainties such as the altitude effect. This pioneering study is expected to facilitate Malawi’s ambition to achieve integrated use and improved protection of its surface water and groundwater resources in response to mounting climate change, growing population and land-development concerns.
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VICKRIDGE, I. C. "APPLICATIONS OF ION BEAM ANALYSIS TO THE ELEMENTAL AND ISOTOPIC CHARACTERISATION OF ADVANCED MATERIALS". Modern Physics Letters B 15, n.º 28n29 (20 de diciembre de 2001): 1271–80. http://dx.doi.org/10.1142/s0217984901003160.
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The accelerator laboratory of the Groupe de Physique des Solides, Paris, has pioneered a number of IBA techniques and applications over the last few decades. In particular, in the 1960's and 1970's, Nuclear Reaction analysis (NRA) including nuclear resonance depth profiling, isotopic tracing combined with NRA, and channelling techniques were developed under the leadership of G. Amsel. In this paper I will present a selection of recent applications from this laboratory of NRA, isotopic tracing with stable isotopes, and ion channelling, intended to illustrate the present status of these techniques in condensed matter physics and materials science, and to act as a backdrop for a discussion of future directions for development of Ion Beam Analysis in condensed matter physics and advanced materials research.
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Hürkamp, Kerstin, Nadine Zentner, Anne Reckerth, Stefan Weishaupt, Karl-Friedrich Wetzel, Jochen Tschiersch y Christine Stumpp. "Spatial and Temporal Variability of Snow Isotopic Composition on Mt. Zugspitze, Bavarian Alps, Germany". Journal of Hydrology and Hydromechanics 67, n.º 1 (1 de marzo de 2019): 49–58. http://dx.doi.org/10.2478/johh-2018-0019.
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Abstract High amounts of precipitation are temporarily stored in high-alpine snow covers and play an important role for the hydrological balance. Stable isotopes of hydrogen (δ2H) and oxygen (δ18O) in water samples have been proven to be useful for tracing transport processes in snow and meltwater since their isotopic ratio alters due to fractionation. In 18 snow profiles of two snowfall seasons, the temporal and spatial variation of isotopic composition was analysed on Mt. Zugspitze. The δ18O and δ2H ranged between -26.7‰ to -9.3‰ and -193.4‰ to -62.5‰ in 2014/2015 and between -26.5‰ to -10.5‰ and -205.0‰ to -68.0‰ in 2015/2016, respectively. Depth-integrated samples of entire 10 cm layers and point measurements in the same layers showed comparable isotopic compositions. Isotopic composition of the snowpack at the same sampling time in spatially distributed snow profiles was isotopically more similar than that analysed at the same place at different times. Melting and refreezing were clearly identified as processes causing isotope fractionation in surficial, initial base or refrozen snow layers. For the future, a higher sampling frequency with detailed isotopic composition measurements during melt periods are recommended to improve the understanding of mass transport associated with snowmelt.
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Rock, L. y B. Mayer. "Tracing nitrates and sulphates in river basins using isotope techniques". Water Science and Technology 53, n.º 10 (1 de mayo de 2006): 209–17. http://dx.doi.org/10.2166/wst.2006.314.
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The objective of this paper is to outline how stable isotope techniques can contribute to the elucidation of the sources and the fate of riverine nitrate and sulphate in watershed studies. The example used is the Oldman River Basin (OMRB), located in southern Alberta (Canada). Increasing sulphate concentrations and decreasing δ34S values along the flowpath of the Oldman River indicate that oxidation of pyrite in tills is a major source of riverine sulphate in the agriculturally used portion of the OMRB. Chemical and isotopic data showed that manure-derived nitrogen contributes significantly to the increase in nitrate concentrations in the Oldman River and its tributaries draining agricultural land. It is suggested that hydrological conditions control agricultural return flows to the surface water bodies in southern Alberta and impart significant seasonal variations on concentrations and isotopic compositions of riverine nitrate. Combining isotopic, chemical, and hydrometric data permitted us to estimate the relative contribution of major sources to the total solute fluxes. Hence, we submit that isotopic measurements can make an important contribution to the identification of nutrient and pollutant sources and to river basin management.
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Wang, Jiaxin, Mingjun Zhang, Athanassios A. Argiriou, Shengjie Wang, Deye Qu, Yu Zhang y Pengyan Su. "Recharge and Infiltration Mechanisms of Soil Water in the Floodplain Revealed by Water-Stable Isotopes in the Upper Yellow River". Sustainability 13, n.º 16 (20 de agosto de 2021): 9369. http://dx.doi.org/10.3390/su13169369.
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The stable isotopes (δD and δ18O) in soil water allow tracing of the flow and transportation of water in the soil. However, there are few studies on the use of soil water stable isotopes to explore the soil water in the floodplain, especially in determining the soil water source and infiltration mechanism. The Bayesian mixing model (MixSIAR) was integrated with the line conditioned excess (lc-excess) of stable isotopes (δD and δ18O) in precipitation, soil water (0–150 cm), river water, and groundwater to determinate the source and recharge mechanisms of two different soil profile types in the floodplain of the upper Yellow River in Lanzhou, China. The results showed that soil water below 80 cm was affected by river water recharge, affecting soil water content and stable isotopic composition at S1 sampling points (profile parallel to river water); this effect was not observed at S2 (profile is higher than the river water) sampling points. The isotopic compositions of the soil water sources at the two sampling points (S1: δD = −77.41‰, δ18O = −11.01‰; S2: δD = −74.02‰, δ18O = −10.56‰) were depleted more than those in the long-term amount-weighted precipitation isotopes (δD = −56.30‰, δ18O = −8.17‰). The isotope signatures of soil water sources are similar to the isotope characteristics of some high-intensity precipitation events (≥30 mm/day), indicating that soil water originates from a fraction of the total precipitation. The piston flow (60%) and the preferential flow (40%) coexist, but soil moisture and rainfall intensity will affect the sequence of the two infiltration methods. This study provides insights for understanding the hydrological process of the upper Yellow River and evaluating groundwater quality and protecting the floodplain environment.
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Sanborn, P. T., R. P. Brockley y B. Mayer. "Stable isotope tracing of fertilizer sulphur uptake by lodgepole pine: foliar responses". Canadian Journal of Forest Research 41, n.º 3 (marzo de 2011): 493–500. http://dx.doi.org/10.1139/x10-222.
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A plot-scale fertilizer sulphur (S) stable isotope tracer study was established in 2001 in the Sub-Boreal Spruce biogeoclimatic zone in central interior British Columbia where S deficiencies are common in lodgepole pine ( Pinus contorta var. latifolia Engelm. ex S. Wats.) stands. Treatments used operationally realistic applications of 300 kg N·ha–1 as urea and 100 kg S·ha–1 as either sulphate (SO4) or elemental S (S0). δ34S values of fertilizer S differed by >9‰ from pretreatment δ34S values of total S in foliage at the two study sites (5.2‰ and 8.2‰). These differences enabled quantification of fertilizer uptake using isotopic analysis of post-treatment foliar S. Addition of K2SO4 with δ34S of +17.5‰ increased foliar δ34S by 3.5‰ and 6.6‰ at the two sites, respectively, in the year after treatment, indicating fertilizer contributions >40% to foliar total S. For a S0 fertilizer application with a δ34S value of +19.3‰, foliar δ34S increases were smaller but steadily increased, resulting in an average tracer S uptake of ~20% over three years. These results confirmed the more rapid availability of S from SO4-based fertilizers and demonstrated the feasibility of field tracer experiments using stable S isotopes at natural abundance levels.
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Bowen, Gabriel J., Zhongyin Cai, Richard P. Fiorella y Annie L. Putman. "Isotopes in the Water Cycle: Regional- to Global-Scale Patterns and Applications". Annual Review of Earth and Planetary Sciences 47, n.º 1 (30 de mayo de 2019): 453–79. http://dx.doi.org/10.1146/annurev-earth-053018-060220.
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Stable isotope ratios of hydrogen and oxygen have been applied to water cycle research for over 60 years. Over the past two decades, however, new data, data compilations, and quantitative methods have supported the application of isotopic data to address large-scale water cycle problems. Recent results have demonstrated the impact of climate variation on atmospheric water cycling, provided constraints on continental- to global-scale land-atmosphere water vapor fluxes, revealed biases in the sources of runoff in hydrological models, and illustrated regional patterns of water use and management by people. In the past decade, global isotopic observations have spurred new debate over the role of soils in the water cycle, with potential to impact both ecological and hydrological theory. Many components of the water cycle remain underrepresented in isotopic databases. Increasing accessibility of analyses and improved platforms for data sharing will refine and grow the breadth of these contributions in the future. ▪ Isotope ratios in water integrate information on hydrological processes over scales from cities to the globe. ▪ Tracing water with isotopes helps reveal the processes that govern variability in the water cycle and may govern future global changes. ▪ Improvements in instrumentation, data sharing, and quantitative analysis have advanced isotopic water cycle science over the past 20 years.
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Du, Kang, Beiying Zhang y Linjuan Li. "Soil Water Dynamics Under Different Land Uses in Loess Hilly Region in China by Stable Isotopic Tracing". Water 13, n.º 2 (19 de enero de 2021): 242. http://dx.doi.org/10.3390/w13020242.
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Exploring soil water dynamics under different land use types is important for water resource management and vegetation restoration in the Loess Plateau. In this study, we investigated the hydrogen and oxygen isotopic compositions of soil water from four different land use types to explore the mechanism of soil water movement and transformation and analyse the influence of land use. The results show that the range of stable isotopes (δD and δ18O) in soil water was smaller than that in precipitation. Values for δD and δ18O in soil water showed relatively similar temporal variation, heavy isotopes were enriched in the soil water in July and depleted in October. Stable isotope values in shallow (<100 cm depth) soil water and deep (>200 cm depth) soil water were low. The δD and δ18O values in woodlands decreased gradually with increasing depth. Across the four land use types, the maximum variation in δD and δ18O was in the shallow depth of the soil profile. Groundwater was recharged mainly from precipitation and then from soil water. The ratio of groundwater recharge by soil water under different land use types followed this rank order: woodland (35.70%) > grassland (31.14%) > shrubland (29.47%) > cropland (29.18%). Matrix flow and preferential flow coexisted during infiltration, and the occurrence of preferential flow was related to the land use type. The main reason for the variation in isotopic composition in soil water is the difference in soil evaporation, which is influenced by different vegetation cover. Owing to the difference in soil evaporation and fractionation, precipitation on cropland, shrubland, and grassland can recharge more soil water than on woodland.
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Raj, Vipin T., J. A. Gayathri, R. K. Sharma, B. L. Redkar, K. Sreelash, D. Padmalal y K. Sajan. "Tracing the Sources of River Waters Using Stable Isotopes (δ18O and δ2H) in Two Mountainous Watersheds, Southern Western Ghats, India". Journal of Geosciences Research 8, n.º 2 (1 de julio de 2023): 89–99. http://dx.doi.org/10.56153/g19088-023-0141-34.
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Stable isotopes of oxygen (δ18O) and hydrogen (δ2H) are useful tools to characterize and monitor the hydrological processes in aquatic ecosystems.The present study uses δ18O and δ2H data from two small catchment rivers such as the east-flowing Bhavani river and the west-flowing Thuthapuzha River in southern Western Ghats to get an insight into the water cycle dynamics and sources of water.The Bhavani River drains through the semi-arid, lee-ward side of the Western Ghats and shows a markedly depleted isotopic composition as compared to the Thuthapuzha River which drains through the humid, windward side of the Western Ghats. The isotopic systematics are strongly influenced by the southwest monsoon (SWM) and the northeast monsoon (NEM) rainfalls. However, during the pre-monsoon (PRM) season, the isotopic composition in these river waters is governed mainly by the baseflow and evaporative processes. Both the river basins experience a higher vapour recycling effect in their headwaters. The NEM rainfall contains a considerable amount of recycled vapour, which is evident from the observed high d-excess values. Whereas the SWM rain events show the dominance of the original sea moisture source. There is a distinct difference in the isotopic ratios and d-excess values between the SWM (d-excess: Bhavani River 10.29 ± 1.29‰; Thuthapuzha River 10.52 ± 2.78‰) and the NEM (d-excess: Bhavani River 15.15 ± 0.92‰; Thuthapuzha River 12.67 ± 4.49‰) seasons, with the predominance of lighter isotopes in the latter period. In general, the seasonal and spatial differences in isotopic composition in the Bhavani River (δ18O: PRM−5.42 ± 1.76‰; SWM−4.16 ± 0.77‰; NEM -4.73 ± 0.76‰) and the Thuthapuzha River (δ18O: PRM −4.26 ± 0.67‰; SWM −2.54 ± 0.76‰; NEM −2.68 ± 0.96‰) indicate that precipitation (atmospheric source) as the major source of water in the monsoon (SWM and NEM) season, while the base flow contribution from groundwater has a major stake in PRM season. Keywords: Stable Water Isotopes, d-excess, Climate Gradient, Base Flow Discharge, Western Ghats, Southwest India
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Lebedeva, Liudmila. "Tracing surface and ground water with stable isotopes in a small permafrost research catchment". E3S Web of Conferences 98 (2019): 12011. http://dx.doi.org/10.1051/e3sconf/20199812011.
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The study aims at assessing groundwater contribution to the streamflow at the small permafrost Shestakovka river watershed in Central Yakutia. Water from stream, lakes, snow, rain, surface flow and suprapermafrost groundwater is characterized by specific isotopic signature. At least one third of the spring flood is formed by “old” pre-event water as showed by mixing model based on stable isotopes as tracers. Presence of talik aquifers associated with sandy hills covered by pine forest suggests that talik groundwater could be an important source of streamflow at the small river basin in continuous permafrost.
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Reutova, Nadezhda, Andrian Seleznev, Ilia Yarmoshenko, Maria Chervyakovskaya y Maria Streletskaya. "Stable Lead Isotopic Ratios as Indicator of Urban Geochemical Processes". IOP Conference Series: Earth and Environmental Science 906, n.º 1 (1 de noviembre de 2021): 012098. http://dx.doi.org/10.1088/1755-1315/906/1/012098.
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Abstract The study is aimed to apply the Pb isotope fingerprinting technique for tracing pollution of urban surface deposited sediment (USDS). USDS reflect changes in the geochemical conditions occurring in the environment. USDS samples were collected in residential areas with multistory buildings in Russian cities: Magnitogorsk, Nizhny Tagil, Tyumen, Ufa, and Chelyabinsk. Elements concentrations and stable Pb isotopic ratios were measured in the samples. The reconstruction of the initial geochemical baseline (IGB) relationship between potentially harmful element (PHE) Pb and conservative lithogenic element (CE) Fe was carried out for USDS sample populations in the cities. The IGB reconstruction divided USDS sample populations into the groups of ‘polluted’ and ‘unpolluted’ with Pb samples. Analysis of elements concentrations and Pb isotope ratios in the groups of USDS samples showed different trends in altering geochemical conditions for metals in the surveyed cities. The USDS is characterized by a decrease in the isotope ratios of 206Pb/204Pb and 208Pb/204Pb as a result of soil pollution by vehicles during the period of using leaded gasoline.
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Bugalho, M. N., P. Barcia, M. C. Caldeira y J. O. Cerdeira. "Stable isotopes as ecological tracers: an efficient method for assessing the contribution of multiple sources to mixtures". Biogeosciences Discussions 5, n.º 3 (9 de junio de 2008): 2425–44. http://dx.doi.org/10.5194/bgd-5-2425-2008.
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Abstract. Stable isotopes are increasingly being used as tracers of ecological processes potentially providing relevant information to environmental management issues. An application of the methodology consists in relating the stable isotopic composition of a sample mixture to that of sources. The number of stable isotopes, however, is usually lower than that of potential sources existing in an ecosystem, which creates mathematical difficulties in correctly tracing sources. We discuss a linear programming model which efficiently derives information on the contribution of sources to mixtures for any number of stable isotopes and any number of sources by addressing multiple sources simultaneously. The model identifies which sources are present in all, present in a subset of the samples or absent from all samples simultaneously and calculates minimum and maximum values of each source in the mixtures. We illustrate the model using a data set consisting on the isotopic signatures of different plant sources ingested by primary consumers in tropical riverine habitat in Asia. The model discussed may contribute to extend the scope of stable isotopes methodology to a range of new problems dealing with multiple sources and multiple tracers. For instance, in food web studies, if particular organic matter sources disappear or decrease in availability (e.g. climate change scenarios) the model allows simulation of alternative diets of the consumers providing potentially relevant information for managers and decision makers.
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Bugalho, M. N., P. Barcia, M. C. Caldeira y J. O. Cerdeira. "Stable isotopes as ecological tracers: an efficient method for assessing the contribution of multiple sources to mixtures". Biogeosciences 5, n.º 5 (25 de septiembre de 2008): 1351–59. http://dx.doi.org/10.5194/bg-5-1351-2008.
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Abstract. Stable isotopes are increasingly being used as tracers of ecological processes potentially providing relevant information to environmental management issues. An application of the methodology consists in relating the stable isotopic composition of a sample mixture to that of sources. The number of stable isotopes, however, is usually lower than that of potential sources existing in an ecosystem, which creates mathematical difficulties in correctly tracing sources. We discuss a linear programming model which efficiently derives information on the contribution of sources to mixtures for any number of stable isotopes and any number of sources by addressing multiple sources simultaneously. The model identifies which sources are present in all, present in a subset of the samples or absent from all samples simultaneously and calculates minimum and maximum values of each source in the mixtures. We illustrate the model using a data set consisting of the isotopic signatures of different plant sources ingested by primary consumers in tropical riverine habitat in Asia. The model discussed may contribute to extend the scope of stable isotopes methodology to a range of new problems dealing with multiple sources and multiple tracers. For instance, in food web studies, if particular organic matter sources disappear or decrease in availability (e.g. climate change scenarios) the model allows simulation of alternative diets of the consumers providing potentially relevant information for managers and decision makers.
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Pershin, Dmitry, Natalia Malygina, Dmitry Chernykh, Roman Biryukov, Dmitry Zolotov y Lilia Lubenets. "Variability in Snowpack Isotopic Composition between Open and Forested Areas in the West Siberian Forest Steppe". Forests 14, n.º 1 (16 de enero de 2023): 160. http://dx.doi.org/10.3390/f14010160.
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The stable water isotopes in snow (primarily 18O and 2H) are widely used for tracing hydrological and ecological processes. However, isotopic signatures of snow can be significantly modified by topography and land cover. This study assesses spatial and temporal variability of the bulk snowpack isotopic composition (δ18O, δ2H, d-excess) between forested (pine and birch) and open areas in the West Siberian forest steppes. Isotopic samples were collected over the peak snow accumulation in 2017–2019. The snow isotopic composition within forested areas differed from open steppes, mainly in reducing d-excess (1.6‰ on average). We did not find a significant effect of canopy interception on snow enrichment in heavier isotopes. Snowpack in the pine forests was even lighter by 3.6‰ for δ2H compared to open areas, probably, due to low energy inputs and interception capacity. Additionally, snow depth significantly influenced the isotopic composition spatial variability. As snow depth increased, δ18O and δ2H values decreased due to conservation within the snowpack and less influence of sublimation and moisture exchange with the soil. However, this pattern was only evident in winters with below-average snow depth. Therefore, taking into account snow depth spatial and seasonal variability is advisable when applying the isotopic methods.
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Zuo, Peijie, Yuming Huang, Jianzhou Bi, Weichao Wang, Wei Li, Dawei Lu, Qinghua Zhang, Qian Liu y Guibin Jiang. "Non-traditional stable isotopic analysis for source tracing of atmospheric particulate matter". TrAC Trends in Analytical Chemistry 158 (enero de 2023): 116866. http://dx.doi.org/10.1016/j.trac.2022.116866.
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Hobson, Keith A., Jacques Sirois y Mark L. Gloutney. "Tracing Nutrient Allocation to Reproduction With Stable Isotopes: A Preliminary Investigation Using Colonial Waterbirds of Great Slave Lake". Auk 117, n.º 3 (1 de julio de 2000): 760–74. http://dx.doi.org/10.1093/auk/117.3.760.
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AbstractWe investigated the use of stable-isotope analysis as a direct means of tracing allocation of endogenous protein and lipid reserves to reproduction in five gulls (Larus canus, L. delawarensis, L. californicus, L. argentatus, L. philadelphia), four terns (Sterna caspia, S. hirundo, S. paradisaea, Chlidonias niger), and one jaeger (Stercorarius parasiticus) breeding on Great Slave Lake (GSL) in the Northwest Territories. Our approach was based on assumptions that (1) body tissues of birds just arriving at GSL from their assumed marine-associated wintering habitats would have stable-isotope ratios more enriched than those of birds in equilibrium with the local GSL foodweb, and (2) mobilization of these reserves to reproduction could be traced by the isotopic measurement of egg macronutrients. As predicted, the pectoral muscle of six species of arriving birds was more enriched in 13C (x̄ = −21.5‰) and 15N (x̄ = 12.7‰) than was that of postbreeding birds (13C, x̄ = −23.5‰; 15N, x̄ = 9.9‰) or hatching-year birds raised at GSL (13C, x̄ = −24.3‰; 15N, x̄ = 9.0‰). Abdominal fat of arriving Herring Gulls and Mew Gulls was more enriched in 13C (x̄ = −19.7‰) than the fat of other species (x̄ = −23.4‰), indicating lipids of marine origin. We compared isotope values of the local GSL foodweb with dietary values predicted from isotope measurements of egg macronutrients if diets were entirely derived at GSL. Isotopic analysis of lipid-free egg yolk, yolk lipid, and shell carbonate suggested that for most species, little if any endogenous protein reserves were used for reproduction, with the possible exception of Caspian Terns, whose egg protein and egg lipid values, and Common Terns, whose egg protein values, were more enriched in 13C than those of the other species. Although endogenous nutrient reserves likely were important to birds during migration and the initial settling period at GSL, local food supplies were adequate to provide nutrients for reproduction.
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Chen, Fenli, Mingjun Zhang, Athanassios A. Argiriou, Shengjie Wang, Xin Zhou y Xueyuan Liu. "Deuterium Excess in Precipitation Reveals Water Vapor Source in the Monsoon Margin Sites in Northwest China". Water 12, n.º 12 (26 de noviembre de 2020): 3315. http://dx.doi.org/10.3390/w12123315.
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The deuterium excess (d) in precipitation, determined by the stable hydrogen and oxygen isotopes (δ2H and δ18O), is a widely applied parameter in tracing the water vapor source. Based on the multiple-year observations of stable water isotopes in precipitation at four stations in the Lanzhou city, Northwest China, we analyzed the variations in deuterium excess in precipitation at the Asian monsoon margin region. The mean value of deuterium excess at the study region is 11.0‰ in the dry season and 8.0‰ in the wet season. The d value in precipitation negatively correlates with air temperature and vapor pressure. The low d value during the wet season reflects the monsoon moisture transported from long distances. During the dry season, the continental air masses correspond to the higher d value in precipitation. The moisture regimes based on reanalysis data are generally consistent with the findings using a stable isotopic approach, and the monsoon moisture is highlighted in summer precipitation at these monsoon margin sites.
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Kusch, S., Y. Kashiyama, N. O. Ogawa, M. Altabet, M. Butzin, J. Friedrich, N. Ohkouchi y G. Mollenhauer. "Implications for chloro- and pheopigment synthesis and preservation from combined compound-specific δ<sup>13</sup>C, δ<sup>15</sup>N, and Δ<sup>14</sup>C analysis". Biogeosciences 7, n.º 12 (23 de diciembre de 2010): 4105–18. http://dx.doi.org/10.5194/bg-7-4105-2010.
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Abstract. Chloropigments and their derivative pheopigments preserved in sediments can directly be linked to photosynthesis. Their carbon and nitrogen stable isotopic compositions have been shown to be a good recorder of recent and past surface ocean environmental conditions tracing the carbon and nitrogen sources and dominant assimilation processes of the phytoplanktonic community. In this study we report results from combined compound-specific radiocarbon and stable carbon and nitrogen isotope analysis to examine the time-scales of synthesis and fate of chlorophyll-a and its degradation products pheophytin-a, pyropheophytin-a, and 132,173-cyclopheophorbide-a-enol until burial in Black Sea core-top sediments. The pigments are mainly of marine phytoplanktonic origin as implied by their stable isotopic compositions. Pigment δ15N values indicate nitrate as the major uptake substrate but 15N-depletion towards the open marine setting indicates either contribution from N2-fixation or direct uptake of ammonium from deeper waters. Radiocarbon concentrations translate into minimum and maximum pigment ages of approximately 40 to 1200 years. This implies that protective mechanisms against decomposition such as association with minerals, storage in deltaic anoxic environments, or eutrophication-induced hypoxia and light limitation are much more efficient than previously thought. Moreover, seasonal variations of nutrient source, growth period, and habitat and their associated isotopic variability are likely at least as strong as long-term trends. Combined triple isotope analysis of sedimentary chlorophyll and its primary derivatives is a powerful tool to delineate biogeochemical and diagenetic processes in the surface water and sediments, and to assess their precise time-scales.
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Ye, Risheng, Jingxin Zhao, Zhiyi Wang, Weiyong Li, Jun He y Fukun Chen. "Single-Grain Detrital Apatite Sr Isotopic Composition as an Indicator to Trace Sedimentary Sources: A Case Study of Sedimentary Rocks in the Hui-Cheng Basin, South Qinling, China". Minerals 13, n.º 8 (29 de julio de 2023): 1010. http://dx.doi.org/10.3390/min13081010.
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Sediments or clastic rocks can record the evolution history of basins, orogenic processes, crustal uplift and erosion, and even paleo-environments. Detrital minerals such as zircon, garnet, and apatite are useful media for studies of sedimentary sources and basin evolution. Detrital zircon has been widely taken as an indicator for provenances and tectonic evolution of geological terrenes via age distribution patterns. Apatite can remain stable during erosion and transportation and is also considered as an ideal object for source tracing. This mineral normally contains high Sr and negligible Rb. Its Sr isotopic composition can remain almost unchanged after crystallization. Unlike isotopic ages of detrital minerals, Apatite isotopic compositions have been less frequently used for tracing the provenance of sedimentary rocks in the last few decades. In the present study, we report on the Sr isotopic composition of individual apatite grains of Neogene and Jurassic conglomerates from the Hui-Cheng basin in the South Qinling orogenic belt, obtained via thermal ionization mass spectrometry. Detrital apatite grains of Jurassic rocks have narrow ranges of 87Sr/86Sr values from 0.7076 to 0.7100, but those of Neogene rocks gave variant 87Sr/86Sr values from 0.7055 to 0.7534, providing distinct evidence for complex sources of Neogene sedimentary rocks. Analytical results show that the distribution patterns of 87Sr/86Sr values of single-grain detrital apatite fit the distribution patterns of detrital zircon U-Pb from the isotopic ages very well. Detrital apatite Sr isotopic composition can provide essential information for tracing the origins and evolution of sedimentary sources.
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Saiki, Makoto, Thu Nga Do, Thuy Hai Cao Thi, Takashi Nakamura, Thao Ta Thi y Kei Nishida. "Temporal variation of stable isotopic values for dissolved nitrogen compounds in paddy water environment". Nuclear Science and Technology 9, n.º 3 (15 de septiembre de 2019): 42–47. http://dx.doi.org/10.53747/jnst.v9i3.44.
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Vietnam is the second-largest rice exporter worldwide and the amount of applied fertilizer is increasing rapidly in recent years. Overuse of chemical fertilizers in the paddy fields strongly contributes to the pollution of water bodies. This study aimed to understand the temporal variation of nitrogen concentrations and stable isotope values as environmental tracers based on the observed data in a selected paddy field in Vietnam, which provides basic and useful clues for tracing sources and identifying processes of nitrogen. The results from the field survey showed that , in accordance withthe changes in concentrations, δ15N values of ammonium and nitrate in ponded water drastically varied from -3.6‰ to 17.2‰ and from -18.2‰ to 8.5‰, respectively. The present study implied that not only chemical fertilizers but also irrigation water was the major source of nitrogen into the paddy. In addition, microbiological nitrification and denitrification were presumed based on the temporal isotopic variations.
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Guo, Jing-Liang, Zaicong Wang, Wen Zhang, Frédéric Moynier, Dandan Cui, Zhaochu Hu y Mihai N. Ducea. "Significant Zr isotope variations in single zircon grains recording magma evolution history". Proceedings of the National Academy of Sciences 117, n.º 35 (18 de agosto de 2020): 21125–31. http://dx.doi.org/10.1073/pnas.2002053117.
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Zircons widely occur in magmatic rocks and often display internal zonation finely recording the magmatic history. Here, we presented in situ high-precision (2SD <0.15‰ for δ94Zr) and high–spatial-resolution (20 µm) stable Zr isotope compositions of magmatic zircons in a suite of calc-alkaline plutonic rocks from the juvenile part of the Gangdese arc, southern Tibet. These zircon grains are internally zoned with Zr isotopically light cores and increasingly heavier rims. Our data suggest the preferential incorporation of lighter Zr isotopes in zircon from the melt, which would drive the residual melt to heavier values. The Rayleigh distillation model can well explain the observed internal zoning in single zircon grains, and the best-fit models gave average zircon–melt fractionation factors for each sample ranging from 0.99955 to 0.99988. The average fractionation factors are positively correlated with the median Ti-in-zircon temperatures, indicating a strong temperature dependence of Zr isotopic fractionation. The results demonstrate that in situ Zr isotope analyses would be another powerful contribution to the geochemical toolbox related to zircon. The findings of this study solve the fundamental issue on how zircon fractionates Zr isotopes in calc-alkaline magmas, the major type of magmas that led to forming continental crust over time. The results also show the great potential of stable Zr isotopes in tracing magmatic thermal and chemical evolution and thus possibly continental crustal differentiation.
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Wang, Jishi, Tianjin Chen, Weixing Zhang, Yan Zhao, Shuming Yang y Ailiang Chen. "Tracing the geographical origin of rice by stable isotopic analyses combined with chemometrics". Food Chemistry 313 (mayo de 2020): 126093. http://dx.doi.org/10.1016/j.foodchem.2019.126093.
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Tian, Lijun, Yongli Gao, Guang Yang, Benjamin Schwartz, Binggui Cai, Christopher Ray, Yunxia Li y Haibin Wu. "Isotopic tracers of sources of water for springs from the Edwards Aquifer, Central Texas, USA". Hydrology Research 52, n.º 3 (20 de mayo de 2021): 787–803. http://dx.doi.org/10.2166/nh.2021.011.
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Abstract The Edwards Aquifer (EA) in Central Texas provides water supply for over two million people and contains springs that are hydrologically and ecologically important to the region. The residence time of groundwater in the EA ranges from a few days to many thousands of years, since water in the aquifer is contained and transported within both matrix porosity and large conduits. In this study, stable isotopes of water from five springs are investigated for tracing the origin of water and hydrological processes in the EA system during 2017–2019. There is a quick response of the isotopic signals measured at these springs to changes in the isotopic compositions of precipitation. By utilizing an isotope mixing model, we have identified sources of water for these springs with a bi-modal distribution of groundwater supply in the EA: water supplied from deep groundwater with a longer residence time (an average of 67%) and supplemental epikarst interflow with a shorter residence time (an average of 33%). The evolution of hydrochemical water types from HCO3–Ca to HCO3·Cl–Ca·Mg along the EA flowpaths indicates that inputs from epikarst interflow are greater in springs within the artesian zone than the springs within the contributing zone.
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Zhou, Jiaxin, Jinkui Wu, Shiwei Liu, Guoxiong Zeng, Jia Qin, Xiuna Wang y Qiudong Zhao. "Hydrograph Separation in the Headwaters of the Shule River Basin: Combining Water Chemistry and Stable Isotopes". Advances in Meteorology 2015 (2015): 1–10. http://dx.doi.org/10.1155/2015/830306.
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The runoff components were identified in the headwater area of Shule River Basin, using isotopic and chemical tracing with particular focus on the temporal variations of catchment sources. A total of 95 samples, including precipitation, groundwater, and glacial meltwater, were collected and analyzed for stable water isotopes (18O and2H) and major chemical ion parameters (potassium, sodium, calcium, magnesium, sulfate, chloride, and bicarbonate). Based on the isotope and water chemistry data, we applied end member mixing analysis (EMMA) to identify and quantify the major runoff generating sources and their contributions. The contributions of groundwater, precipitation, and glacial meltwater were 66.7%, 19.9%, and 13.4%, respectively. The study indicated that groundwater dominated runoff in the headwater area of Shule River Basin. The roles of glacier meltwater should be remarkable in water resource management in this basin. The uncertainties of the EMMA method were summarized and estimated via a classical Gaussian error propagation technique. Analyses suggested that the uncertainty in the measurement method was less important than that in the temporal and spatial variations of tracer concentrations. The uncertainty was sensitive when the difference between mixing components was small. Therefore, the variation of tracers and the difference of mixing components should be considered when hydrograph separation was applied in the basin.
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Kusch, S., Y. Kashiyama, N. O. Ogawa, M. Altabet, M. Butzin, J. Friedrich, N. Ohkouchi y G. Mollenhauer. "Implications for chloro- and pheopigment synthesis and preservation from combined compound-specific δ<sup>13</sup>C, δ<sup>15</sup>N, and Δ<sup>14</sup>C analysis". Biogeosciences Discussions 7, n.º 4 (20 de agosto de 2010): 6265–94. http://dx.doi.org/10.5194/bgd-7-6265-2010.
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Abstract. Chloropigments and their derivative pheopigments preserved in sediments can directly be linked to photosynthesis. Their carbon and nitrogen stable isotopic compositions have been shown to be a good recorder of recent and past surface ocean environmental conditions tracing the carbon and nitrogen sources and dominant assimilation processes of the phytoplanktonic community. In this study we report results from combined compound-specific radiocarbon and stable carbon and nitrogen isotopic analysis to examine the timescales of synthesis and fate of chlorophyll-a and its degradation products pheophytin-a, pyropheophytin-a, and 132,173-cyclopheophorbide-a-enol until burial in Black Sea surface sediments. The pigments are mainly of marine phytoplanktonic origin as implied by their stable isotopic compositions. Pigment δ15N values indicate nitrate as the major uptake substrate but 15N-depletion towards the open marine setting indicates contribution from N2-fixation. Radiocarbon concentrations translate into minimum and maximum pigment ages of approximately 40 to 1200 years. This implies that protective mechanisms against decomposition such as association with minerals or eutrophication-induced hypoxia and light limitation are much more efficient than previously thought. However, seasonal variations of nutrient source, growth period, and habitat and their associated isotopic variability are likely at least as strong as long-term trends. Combined triple isotopic analysis of sedimentary chlorophyll and its primary derivatives is a powerful tool to delineate biogeochemical and diagenetic processes in the surface water and assess their precise timescales.
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Ingraham, Neil L., R. J. Johnson y Robert Broadbent. "Facility-Altered Stable Isotopic Ratios of Power Generation Cooling Wastewater: Opportunity for Tracing Leakages". Environmental Science & Technology 28, n.º 11 (octubre de 1994): 1983–86. http://dx.doi.org/10.1021/es00060a032.
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Kiss, Gabriella B., Kata Molnár, Zsolt Benkó, Péter Skoda, Zsuzsanna Kapui, Giorgio Garuti, Federica Zaccarini, László Palcsu y György Czuppon. "Tracing the Source of Hydrothermal Fluid in Ophiolite-Related Volcanogenic Massive Sulfide Deposits: A Case Study from the Italian Northern Apennines". Minerals 13, n.º 1 (21 de diciembre de 2022): 8. http://dx.doi.org/10.3390/min13010008.
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The Italian Northern Apennines contain several Fe-Cu-Zn-bearing, Cyprus-type volcanogenic massive sulfide (VMS) deposits, which significantly contribute to the Cu resources of Italy. The massive sulfide lenses and related stockwork mineralizations are hosted by several levels (from basalt to serpentinite) of the unmetamorphosed ophiolitic series; therefore, this region offers perfect locations to study the ore-forming hydrothermal system in detail. A combination of fluid inclusion microthermometry, Raman spectroscopy, electron probe analyses (chlorite thermometry) and stable and noble gas isotope geochemistry was used to determine the fluid source of the VMS system at Bargone, Boccassuolo, Campegli, Casali–Monte Loreto, Corchia, Reppia and Vigonzano. This question of the fluid source is the focus of modern VMS research worldwide, as it has a direct influence on the metal content of the deposit. The obtained temperature and compositional data are both in the typical range of VMS systems and basically suggest evolved seawater origin for the mineralizing fluid. Modification of seawater was most commonly due to fluid–rock interaction processes, which happened during long-lasting circulation in the crust. The role of a small amount of magmatic fluid input was traced only at the lower block of Boccassuolo, which may be responsible for its higher ore grade. This fluid origin model is evidenced by O, H and C stable isotopic as well as He, Ne and Ar noble gas isotopic values.
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Hartland, Adam, Graham D. Fenwick y Sarah J. Bury. "Tracing sewage-derived organic matter into a shallow groundwater food web using stable isotope and fluorescence signatures". Marine and Freshwater Research 62, n.º 2 (2011): 119. http://dx.doi.org/10.1071/mf10110.
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Little is known about the feeding modes of groundwater invertebrates (stygofauna). Incorporation of sewage-derived organic matter (OM) into a shallow groundwater food web was studied using fluorescence and stable isotope signatures (δ13C and δ15N). Organic pollution was hypothesised to limit sensitive species’ abundances along the contamination gradient and isotope signatures of stygofauna consuming sewage-derived OM were expected to be enriched in δ15N. Stygofauna communities near a sewage treatment plant in New Zealand were sampled over 4 months and microbial biofilms were incubated in situ on native gravel for 1 month. As anticipated, OM stress-subsidy gradients altered stygofauna composition: the biomass of oligochaetes and Paraleptamphopus amphipods increased in OM-enriched groundwater (higher dissolved organic carbon (DOC) and tryptophan-like fluorescence), whereas other, probably less-tolerant taxa (e.g. ostracods, Dytiscidae) were absent. Isotopic signatures for stygofauna from polluted groundwater were consistent with assimilation of isotopically enriched sewage-N (δ15N values of 7–16‰), but highly depleted in δ13C relative to sewage. Negative 13C discriminations probably occur in Paraleptamphopus amphipods, and may also occur in oligochaetes and Dytiscidae, a finding with implications for the application of δ13C for determining food sources in groundwaters. Organic pollution of groundwaters may have serious repercussions for stygofauna community structure with potentially irreversible consequences.
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Lerch, Thomas Z., Marie-France Dignac, Enrique Barriuso y André Mariotti. "Effect of Glucose on the Fatty Acid Composition of Cupriavidus necator JMP134 during 2,4-Dichlorophenoxyacetic Acid Degradation: Implications for Lipid-Based Stable Isotope Probing Methods". Applied and Environmental Microbiology 77, n.º 20 (19 de agosto de 2011): 7296–306. http://dx.doi.org/10.1128/aem.06438-11.
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ABSTRACTCombining lipid biomarker profiling with stable isotope probing (SIP) is a powerful technique for studying specific microbial populations responsible for the degradation of organic pollutants in various natural environments. However, the presence of other easily degradable substrates may induce significant physiological changes by altering both the rate of incorporation of the target compound into the biomass and the microbial lipid profiles. In order to test this hypothesis,Cupriavidus necatorJMP134, a 2,4-dichlorophenoxyacetic acid (2,4-D)-degrading bacterium, was incubated with [13C]2,4-D, [13C]glucose, or mixtures of both substrates alternatively labeled with13C.C. necatorJMP134 exhibited a preferential use of 2,4-D over glucose. The isotopic analysis showed that glucose had only a small effect on the incorporation of the acetic chain of 2,4-D into the biomass (at days 2 and 3) and no effect on that of the benzenic ring. The addition of glucose did change the fatty acid methyl ester (FAME) composition. However, the overall FAME isotopic signature reflected that of the entire biomass. Compound-specific individual isotopic analyses of FAME composition showed that the13C-enriched FAME profiles were slightly or not affected when tracing the 2,4-D acetic chain or 2,4-D benzenic ring, respectively. This batch study is a necessary step for validating the use of lipid-based SIP methods in complex environments.
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Perini, Matteo, Mohamadou Bawe Nfor, Federica Camin, Silvia Pianezze y Edi Piasentier. "Using Bioelements Isotope Ratios and Fatty Acid Composition to Deduce Beef Origin and Zebu Feeding Regime in Cameroon". Molecules 26, n.º 8 (8 de abril de 2021): 2155. http://dx.doi.org/10.3390/molecules26082155.
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The purpose of this study was to address the lack of knowledge regarding the stable isotopic composition of beef from zebu cattle reared in tropical Africa. Sixty beef carcasses belonging to the most common zebu breeds (Goudali, white Fulani, and red Mbororo) were selected and classified according to their subcutaneous fat color (white, cream or yellow). The stable isotope ratios of five bioelements—H, O, C, N, and S—in muscle fractions and the fatty acids composition were analyzed. Zebu meat from Cameroon shows peculiar δ13C values, related to the almost exclusive intake of grazed tropical grasses with photosynthetic cycle C4. It also shows δ2H and δ18O values higher than those reported in other areas of the world and correlated with the isotopic composition of animal drinking water. The white subcutaneous fat (“white type”) zebu showed higher δ2H and lower δ13C than the “yellow type”, that is correlated with a higher content of polyunsaturated fatty acid (PUFA) and a lower amount of saturated fatty acid (SFA) and monounsaturated fatty acid (MUFA). Multielement analysis seems to provide promising results for tracing the regional origin of Cameroon beef and some aspects of the livestock system, such as the nutritional status of the animals.
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Soto, David X., Leonard I. Wassenaar, Keith A. Hobson y Jordi Catalan. "Effects of size and diet on stable hydrogen isotope values (δD) in fish: implications for tracing origins of individuals and their food sources". Canadian Journal of Fisheries and Aquatic Sciences 68, n.º 11 (noviembre de 2011): 2011–19. http://dx.doi.org/10.1139/f2011-112.
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Recent studies suggest that stable hydrogen isotope ratios (δD) of fish can be used to track their watershed origin and the relative contributions of source material. Both applications assume that there is no metabolic or trophic effect on tissue δD. We studied the local variation of δD values in four fish species of contrasting size and feeding habits in an isotopically homogenous reservoir (Flix, Spain). Other isotopic values (δ15N, δ13C) and trace metal content were measured as indicators of trophic and bioaccumulation patterns. In addition, isotopic values (δD, δ15N, δ13C) of other food web components were measured for comparison. Muscle δD values differed greatly among fish species: European catfish, Silurus glanis (–131‰); common carp, Cyprinus carpio (–141‰); rudd, Scardinius erythrophthalmus (–158‰); and roach, Rutilus rutilus (–163‰). The influence of fish size and trophic position affected the fish δD values. Possible mechanisms that drive δD variation among fish might be a metabolic effect and (or) the compounding effect of ambient water δD on exchangeable H at each trophic stage. Our findings showed that size and feeding habits are factors that should be controlled when tracing origins of fish or their dependence on nutrient inputs using δD measurements.
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Sealy, Judith, Richard Armstrong y Carmel Schrire. "Beyond lifetime averages: tracing life histories through isotopic analysis of different calcified tissues from archaeological human skeletons". Antiquity 69, n.º 263 (junio de 1995): 290–300. http://dx.doi.org/10.1017/s0003598x00064693.
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Stable-isotopic analyses of human bone, now an established aid to dietary reconstruction in archaeology, represent the diet as averaged over many years. Separate analysis of different skeletal components enables changes in diet and place of residence to be tracked, giving a fuller life-history for long-dead individuals.
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Ding, Weitian, Urumu Tsunogai, Fumiko Nakagawa, Takashi Sambuichi, Hiroyuki Sase, Masayuki Morohashi y Hiroki Yotsuyanagi. "Tracing the source of nitrate in a forested stream showing elevated concentrations during storm events". Biogeosciences 19, n.º 13 (11 de julio de 2022): 3247–61. http://dx.doi.org/10.5194/bg-19-3247-2022.
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Abstract. To clarify the source of nitrate increased during storm events in a temperate forested stream, we monitored temporal variation in the concentrations and stable isotopic compositions including Δ17O of stream nitrate in a forested catchment (KJ catchment, Japan) during three storm events: I, II, and III (summer). The stream showed a significant increase in nitrate concentration, from 24.7 to 122.6 µM, from 28.7 to 134.1 µM, and from 46.6 to 114.5 µM, during the storm events I, II, and III, respectively. On the other hand, the isotopic compositions (δ15N, δ18O, and Δ17O) of stream nitrate showed a decrease in accordance with the increase in the stream nitrate concentration, from +2.5 ‰ to −0.1 ‰, from +3.0 ‰ to −0.5 ‰, and from +3.5 ‰ to −0.1 ‰, for δ15N; from +3.1 ‰ to −3.4 ‰, from +2.9 ‰ to −2.5 ‰, and from +2.1 ‰ to −2.3 ‰ for δ18O; and from +1.6 ‰ to +0.3 ‰, from +1.4 ‰ to +0.3 ‰, and from +1.2 ‰ to +0.5 ‰, for Δ17O during the storm events I, II, and III, respectively. Besides, we found strong linear relationships between the isotopic compositions of stream nitrate and the reciprocal of stream nitrate concentrations during each storm event, implying that the temporal variation in the stream nitrate can be explained by simple mixing between two distinctive endmembers of nitrate having different isotopic compositions. Furthermore, we found that both concentrations and the isotopic compositions of soil nitrate obtained in the riparian zone of the stream were plotted on the nitrate-enriched extension of the linear relationship. We concluded that the soil nitrate in the riparian zone was primarily responsible for the increase in stream nitrate during the storm events. In addition, we found that the concentration of unprocessed atmospheric nitrate in the stream was stable at 1.6 ± 0.4, 1.8 ± 0.4, and 2.1 ± 0.4 µM during the storm events I, II, and III, respectively, irrespective of the significant variations in the total nitrate concentration. We concluded that the storm events have fews impacts on the concentration of unprocessed atmospheric nitrate in the stream, and thus the annual export flux of unprocessed atmospheric nitrate relative to the annual deposition flux can be a robust index to evaluate nitrogen saturation in forested catchments, irrespective to the variation in the number of storm events and/or the variation in the elapsed time from storm events to sampling.
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Conte, Federica, Marek J. Noga, Monique van Scherpenzeel, Raisa Veizaj, Rik Scharn, Juda-El Sam, Chiara Palumbo et al. "Isotopic Tracing of Nucleotide Sugar Metabolism in Human Pluripotent Stem Cells". Cells 12, n.º 13 (3 de julio de 2023): 1765. http://dx.doi.org/10.3390/cells12131765.
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Metabolism not only produces energy necessary for the cell but is also a key regulator of several cellular functions, including pluripotency and self-renewal. Nucleotide sugars (NSs) are activated sugars that link glucose metabolism with cellular functions via protein N-glycosylation and O-GlcNAcylation. Thus, understanding how different metabolic pathways converge in the synthesis of NSs is critical to explore new opportunities for metabolic interference and modulation of stem cell functions. Tracer-based metabolomics is suited for this challenge, however chemically-defined, customizable media for stem cell culture in which nutrients can be replaced with isotopically labeled analogs are scarcely available. Here, we established a customizable flux-conditioned E8 (FC-E8) medium that enables stem cell culture with stable isotopes for metabolic tracing, and a dedicated liquid chromatography mass-spectrometry (LC-MS/MS) method targeting metabolic pathways converging in NS biosynthesis. By 13C6-glucose feeding, we successfully traced the time-course of carbon incorporation into NSs directly via glucose, and indirectly via other pathways, such as glycolysis and pentose phosphate pathways, in induced pluripotent stem cells (hiPSCs) and embryonic stem cells. Then, we applied these tools to investigate the NS biosynthesis in hiPSC lines from a patient affected by deficiency of phosphoglucomutase 1 (PGM1), an enzyme regulating the synthesis of the two most abundant NSs, UDP-glucose and UDP-galactose.
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Won, Eun-Ji, Hee-Young Yun, Dong-Hun Lee y Kyung-Hoon Shin. "Application of Compound-Specific Isotope Analysis in Environmental Forensic and Strategic Management Avenue for Pesticide Residues". Molecules 26, n.º 15 (21 de julio de 2021): 4412. http://dx.doi.org/10.3390/molecules26154412.
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Unintended pesticide pollution in soil, crops, and adjacent environments has caused several issues for both pesticide users and consumers. For users, pesticides utilized should provide higher yield and lower persistence while considering both the environment and agricultural products. Most people are concerned that agricultural products expose humans to pesticides accumulating in vegetation. Thus, many countries have guidelines for assessing and managing pesticide pollution, for farming in diverse environments, as all life forms in soil are untargeted to these pesticides. The stable isotope approach has been a useful technique to find the source of organic matter in studies relating to aquatic ecology and environmental sciences since the 1980s. In this study, we discuss commonly used analytical methods using liquid and gas chromatography coupled with isotopic ratio mass spectrometry, as well as the advanced compound-specific isotope analysis (CSIA). CSIA applications are discussed for tracing organic pollutants and understanding chemical reactions (mechanisms) in natural environments. It shows great applicability for the issues on unintended pesticide pollution in several environments with the progress history of isotope application in agricultural and environmental studies. We also suggest future study directions based on the forensic applications of stable isotope analysis to trace pesticides in the environment and crops.
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Wang, Zhijun, Sara W. Erasmus y Saskia M. van Ruth. "Preliminary Study on Tracing the Origin and Exploring the Relations between Growing Conditions and Isotopic and Elemental Fingerprints of Organic and Conventional Cavendish Bananas (Musa spp.)". Foods 10, n.º 5 (8 de mayo de 2021): 1021. http://dx.doi.org/10.3390/foods10051021.
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The stable isotopic ratios and elemental compositions of 120 banana samples, Musa spp. (AAA Group, Cavendish Subgroup) cultivar Williams, collected from six countries (Colombia, Costa Rica, Dominica Republic, Ecuador, Panama, Peru), were determined by isotope ratio mass spectrometry and inductively coupled plasma mass spectrometry. Growing conditions like altitude, temperature, rainfall and production system (organic or conventional cultivation) were obtained from the sampling farms. Principal component analysis (PCA) revealed separation of the farms based on geographical origin and production system. The results showed a significant difference in the stable isotopic ratios (δ13C, δ15N, δ18O) and elemental compositions (Al, Ba, Cu, Fe, Mn, Mo, Ni, Rb) of the pulp and peel samples. Furthermore, δ15N was found to be a good marker for organically produced bananas. A correlation analysis was conducted to show the linkage of growing conditions and compositional attributes. The δ13C of pulp and peel were mainly negatively correlated with the rainfall, while δ18O was moderately positively (R values ~0.5) correlated with altitude and temperature. A moderate correlation was also found between temperature and elements such as Ba, Fe, Mn, Ni and Sr in the pulp and peel samples. The PCA results and correlation analysis suggested that the differences of banana compositions were combined effects of geographical factors and production systems. Ultimately, the findings contribute towards understanding the compositional differences of bananas due to different growing conditions and production systems linked to a defined origin; thereby offering a tool to support the traceability of commercial fruits.
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Wagner, Luise J., Ilka C. Kleinhanns, Nadja Weber, Michael G. Babechuk, Axel Hofmann y Ronny Schoenberg. "Coupled stable chromium and iron isotopic fractionation tracing magmatic mineral crystallization in Archean komatiite-tholeiite suites". Chemical Geology 576 (agosto de 2021): 120121. http://dx.doi.org/10.1016/j.chemgeo.2021.120121.
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Wang, Feifei, Lihua Liu, Wenfeng Xu, Yasong Li, Qizhen Ruan y Wenzhi Cao. "Multiple stable isotopic approaches for tracing nitrate contamination sources: Implications for nitrogen management in complex watersheds". Ecotoxicology and Environmental Safety 269 (enero de 2024): 115822. http://dx.doi.org/10.1016/j.ecoenv.2023.115822.
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Hong, Liu, Wenyuan Wang, Yang Su, Guiping Zhang, Yong Su, Chenming Zhang, Jianhua Chen et al. "Identifying the Geographical Origin of Tobacco Leaf by Strontium and Lead Isotopic with Mineral Elemental Fingerprint". International Journal of Chemical Engineering 2022 (21 de junio de 2022): 1–10. http://dx.doi.org/10.1155/2022/5949770.
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The primary aim of this paper was to identifying the geographical origin of tobacco leaves based on stable isotopic and mineral elemental fingerprint. We collected eighty-one tobacco leaf samples from Argentina, Brazil, Zimbabwe, the U.S., Zambia, and China. And nine mineral element contents and four strontium and lead isotope ratios of the tobacco leaves were determined by thermal ionization mass spectrometry (TIMS) and inductively coupled plasma mass spectrometry (ICP-MS). After variance and stepwise discriminant analysis, the discriminant functions of the tobacco leaf’s geographical origin were established. The results indicate that: (1) the contents of six mineral elements including Cu, Zn, Cr, Ni, Cd, and Pb, together with four strontium and lead isotope ratios containing 87Sr/86Sr, 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb, were significantly different among six countries. (2) Different countries presented some characteristic mineral elemental and isotopic fingerprint. The even contents of mineral elements from Zambian tobacco leaf were much lower than the other countries, among which four elements consisting of Zn, Cr, As, and Cd were not detected. The three average lead isotope ratios including 208Pb/204Pb, 207Pb/204Pb, and 206Pb/204Pb from Zimbabwe tobacco leaves were far higher than the other countries, and the range of which was unoverlapped. (3) The effective identification of the geographical origin of tobacco leaf was accomplished by Fisher stepwise discriminant analysis and the characteristic tracing elements consisted of Cu, Zn, Cr, Ni, Cd, Pb, 87Sr/86Sr, 207Pb/204Pb, and 206Pb/204Pb. Based on the established discriminant functions, the original and cross-validation accuracy towards different geographical origins of tobacco leaves were 98.8% and 95.1%, respectively. The study shows that the strontium and lead isotopic with mineral elemental fingerprints is a potential effective method to identify the geographical origin of tobacco leaves from different countries.
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Eichler, P. P. B., K. Billups, H. Vital y J. A. De Moraes. "TRACING THERMOHALINE PROPERTIES AND PRODUCTIVITY OF SHELF-WATER MASSES USING THE STABLE ISOTOPIC COMPOSITION OF BENTHIC FORAMINIFERA". Journal of Foraminiferal Research 44, n.º 4 (1 de octubre de 2014): 352–64. http://dx.doi.org/10.2113/gsjfr.44.4.352.
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Amin, Anam, Giulia Zuecco, Chiara Marchina, Michael Engel, Daniele Penna, Jeffrey J. McDonnell y Marco Borga. "No evidence of isotopic fractionation in olive trees (Olea europaea): a stable isotope tracing experiment". Hydrological Sciences Journal 66, n.º 16 (24 de noviembre de 2021): 2415–30. http://dx.doi.org/10.1080/02626667.2021.1987440.
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