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Haberstroh S, Kübert A, Werner C. Two common pitfalls in the analysis of water-stable isotopologues with cryogenic vacuum extraction and cavity ring-down spectroscopy. ANALYTICAL SCIENCE ADVANCES 2024; 5:2300053. [PMID: 38827022 PMCID: PMC11142394 DOI: 10.1002/ansa.202300053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/21/2023] [Revised: 01/08/2024] [Accepted: 01/11/2024] [Indexed: 06/04/2024]
Abstract
Water stable isotopologue analysis is widely used to disentangle ecohydrological processes. Yet, there are increasing reports of measurement uncertainties for established and emerging methods, such as cryogenic vacuum extraction (CVE) or cavity ring-down spectroscopy (CRDS). With this study, we investigate two pitfalls, that potentially contribute to uncertainties in water-stable isotopologue research. To investigate fractionation sources in CVE, we extracted pure water of known isotopic composition with cotton, glass wool or without cover and compared the isotopologue results with non-extracted reference samples. To characterise the dependency of δ2H and δ18O on the water mixing ratio in CRDS, which is of high importance for in-situ applications with large natural variations in mixing ratios, we chose samples with a large range of isotopic compositions and determined δ2H and δ18O for different water mixing ratios with two CRDS analysers (Picarro, Inc.). Cotton wool had a strong fractionation effect on δ2H values, which increased with more 2H-enriched samples. δ2H and δ18O values showed a strong dependency on the water mixing ratio analysed with CRDS with differences of up to 34.5‰ (δ2H) and 3.9‰ (δ18O) for the same sample at different mixing ratios. CVE and CRDS, now routinely applied in water stable isotopologue research, come with pitfalls, namely fractionation effects of cover materials and water mixing ratio dependencies of δ2H and δ18O, which can lead to erroneous isotopologue results and thus, invalid conclusions about (ecohydrological) processes. These practical issues identified here should be reported and addressed adequately in water-stable isotopologue research.
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Affiliation(s)
- Simon Haberstroh
- Ecosystem PhysiologyFaculty of Environment and Natural ResourcesInstitute of Earth and Environmental SciencesUniversity FreiburgFreiburgGermany
| | - Angelika Kübert
- Ecosystem PhysiologyFaculty of Environment and Natural ResourcesInstitute of Earth and Environmental SciencesUniversity FreiburgFreiburgGermany
- Institute for Atmospheric and Earth System Research (INAR)University of HelsinkiHelsinkiFinland
| | - Christiane Werner
- Ecosystem PhysiologyFaculty of Environment and Natural ResourcesInstitute of Earth and Environmental SciencesUniversity FreiburgFreiburgGermany
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Kühnhammer K, Dahlmann A, Iraheta A, Gerchow M, Birkel C, Marshall JD, Beyer M. Continuous in situ measurements of water stable isotopes in soils, tree trunk and root xylem: Field approval. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2022; 36:e9232. [PMID: 34862674 DOI: 10.1002/rcm.9232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 11/26/2021] [Accepted: 11/27/2021] [Indexed: 06/13/2023]
Abstract
RATIONALE New methods to measure stable isotopes of soil and tree water directly in the field enable us to increase the temporal resolution of obtained data and advance our knowledge on the dynamics of soil and plant water fluxes. Only few field applications exist. However, these are needed to further improve novel methods and hence exploit their full potential. METHODS We tested the borehole equilibration method in the field and collected in situ and destructive samples of stable isotopes of soil, trunk and root xylem water over a 2.5-month experiment in a tropical dry forest under natural abundance conditions and following labelled irrigation. Water from destructive samples was extracted using cryogenic vacuum extraction. Isotope ratios were determined with IRIS instruments using cavity ring-down spectroscopy both in the field and in the laboratory. RESULTS In general, timelines of both methods agreed well for both soil and xylem samples. Irrigation labelled with heavy hydrogen isotopes clearly impacted the isotope composition of soil water and one of the two studied tree species. Inter-method deviations increased in consequence of labelling, which revealed their different capabilities to cover spatial and temporal heterogeneities. CONCLUSIONS We applied the novel borehole equilibration method in a remote field location. Our experiment reinforced the potential of this in situ method for measuring xylem water isotopes in both tree trunks and roots and confirmed the reliability of gas permeable soil probes. However, in situ xylem measurements should be further developed to reduce the uncertainty within the range of natural abundance and hence enable their full potential.
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Affiliation(s)
- Kathrin Kühnhammer
- IGOE, Environmental Geochemistry, Braunschweig, Germany
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
| | - Adrian Dahlmann
- IGOE, Environmental Geochemistry, Braunschweig, Germany
- Ecosystem Physiology, University of Freiburg, Freiburg, Germany
| | | | | | - Christian Birkel
- Department of Geography and Water and Global Change Observatory, Universidad de Costa Rica (UCR), San José, Costa Rica
| | - John D Marshall
- Department of Forest Ecology and Management, Faculty of Forest Sciences, Swedish University of Agricultural Sciences, Umeå, Sweden
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Gessler A, Bächli L, Rouholahnejad Freund E, Treydte K, Schaub M, Haeni M, Weiler M, Seeger S, Marshall J, Hug C, Zweifel R, Hagedorn F, Rigling A, Saurer M, Meusburger K. Drought reduces water uptake in beech from the drying topsoil, but no compensatory uptake occurs from deeper soil layers. THE NEW PHYTOLOGIST 2022; 233:194-206. [PMID: 34610146 PMCID: PMC9293437 DOI: 10.1111/nph.17767] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 09/26/2021] [Indexed: 06/02/2023]
Abstract
The intensity and frequency of droughts events are projected to increase in future with expected adverse effects for forests. Thus, information on the dynamics of tree water uptake from different soil layers during and after drought is crucial. We applied an in situ water isotopologue monitoring system to determine the oxygen isotope composition in soil and xylem water of European beech with a 2-h resolution together with measurements of soil water content, transpiration and tree water deficit. Using a Bayesian isotope mixing model, we inferred the relative and absolute contribution of water from four different soil layers to tree water use. Beech took up more than 50% of its water from the uppermost 5 cm soil layer at the beginning of the 2018 drought, but then reduced absolute water uptake from the drying topsoil by 84%. The trees were not able to quantitatively compensate for restricted topsoil water availability by additional uptake from deeper soil layers, which is related to the fine root depth distribution. Absolute water uptake from the topsoil was restored to pre-drought levels within 3 wk after rewetting. These uptake patterns help to explain both the drought sensitivity of beech and its high recovery potential after drought release.
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Affiliation(s)
- Arthur Gessler
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
- Institute of Terrestrial EcosystemsETH Zurich8092ZurichSwitzerland
| | - Lukas Bächli
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
| | | | - Kerstin Treydte
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
| | - Marcus Schaub
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
| | - Matthias Haeni
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
| | - Markus Weiler
- Hydrology, Faculty of Environment and Natural ResourcesUniversity of Freiburg79098FreiburgGermany
| | - Stefan Seeger
- Hydrology, Faculty of Environment and Natural ResourcesUniversity of Freiburg79098FreiburgGermany
| | - John Marshall
- Department of Forest Ecology and ManagementSwedish University of Agricultural SciencesUmeå90283Sweden
| | - Christian Hug
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
| | - Roman Zweifel
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
| | - Frank Hagedorn
- Research Unit Forest Soils and BiogeochemistrySwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
| | - Andreas Rigling
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
- Institute of Terrestrial EcosystemsETH Zurich8092ZurichSwitzerland
| | - Matthias Saurer
- Research Unit Forest DynamicsSwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
| | - Katrin Meusburger
- Research Unit Forest Soils and BiogeochemistrySwiss Federal Research Institute for Forest, Snow and Landscape Research WSL8903BirmensdorfSwitzerland
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Cui J, Lide T, Yu W. Organic contamination in online laser-based plant stem and leaf water isotope measurements for pre-extracted samples. ISOTOPES IN ENVIRONMENTAL AND HEALTH STUDIES 2021; 57:262-270. [PMID: 33594914 DOI: 10.1080/10256016.2021.1883010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/17/2020] [Indexed: 06/12/2023]
Abstract
Water stable isotopes have been widely used as natural tracers to investigate soil-plant-atmosphere interactions. Recent developments in induction module cavity ring-down spectroscopy (IM-CRDS) have made it possible to rapidly complete isotope analyses, and to combust co-extracted organic compounds at the same time. However, the agreement between IM-CRDS and isotope ratio mass spectrometry (IRMS) analyses has generally been poor and was primarily attributable to spectral interference of IM-CRDS. Here we evaluated the impacts of organic contamination on the isotope ratios using IM-CRDS with two different methods. No spectral interference was observed for solid samples measured directly by IM-CRDS, whereas clear organic contamination occurred in isotope analyses for pre-extracted plant stem and leaf samples. Our results demonstrate that IM-CRDS can fully combust co-extracted organic compounds by in-line oxidation in the direct measurement of solid samples, although this may not guarantee that the IM-CRDS can obtain better isotopic data than IRMS. It may be risky to evaluate the performance of IM-CRDS by measuring pre-extracted water samples because cryogenic vacuum distillation is likely to introduce extra organic compounds, which may not be fully removed during subsequent IM-CRDS measurement. In addition, spectral variables are useful for post-processing corrections.
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Affiliation(s)
- Jiangpeng Cui
- Key Laboratory of Tibetan Plateau Environment Change and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, People's Republic of China
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, People's Republic of China
| | - Tian Lide
- Key Laboratory of Tibetan Plateau Environment Change and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, People's Republic of China
- CAS Centre for Excellence in Tibetan Plateau Earth Sciences, Beijing, People's Republic of China
- Institute of International Rivers and Eco-Security, Yunnan University, Kunming, People's Republic of China
| | - Wusheng Yu
- Key Laboratory of Tibetan Plateau Environment Change and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, People's Republic of China
- CAS Centre for Excellence in Tibetan Plateau Earth Sciences, Beijing, People's Republic of China
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Qu D, Tian L, Zhao H, Yao P, Xu B, Cui J. Demonstration of a memory calibration method in water isotope measurement by laser spectroscopy. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2020; 34:e8689. [PMID: 31802558 DOI: 10.1002/rcm.8689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 12/04/2019] [Accepted: 12/04/2019] [Indexed: 06/10/2023]
Abstract
RATIONALE Measuring δ18 O and δ2 H values in water using wavelength-scanned cavity ring down spectroscopy (WS-CRDS) requires multiple injections of up to six (and sometimes eight or more) of one sample to remove the memory effect, which decreases the sample throughput and increases the consumables cost. Thus, improved methods for removing the memory effect are required. METHODS We calculated the memory coefficients by sequential WS-CRDS measurement of two lab standard waters with isotopic differences, and used them to establish calibration equations. We then used these equations to correct the measured δ18 O and δ2 H values by removing the memory effect, instead of using multiple injections in the routine daily measurements. RESULTS By using this method, the number of injections per sample was reduced to one. The reproducibility (one standard deviation) of the δ18 O and δ2 H values obtained for quality control sample was less than 0.05‰ and 0.5‰ for an annual average, respectively. CONCLUSIONS By measuring the memory coefficients and establishing the calibration equations, a highly effective method was developed for determining the δ18 O and δ2 H values of water, which could significantly improve sample throughput for liquid water dual isotope measurement without sacrificing the precision.
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Affiliation(s)
- Dongmei Qu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, CAS, Beijing, 100101, China
| | - Lide Tian
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, CAS, Beijing, 100101, China
- Institute of International Rivers and Eco-Security, Yunnan University, Kunming, Yunnan, 650091, China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China
| | - Huabiao Zhao
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, CAS, Beijing, 100101, China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China
| | - Ping Yao
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, CAS, Beijing, 100101, China
| | - Baiqing Xu
- Key Laboratory of Tibetan Environment Changes and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, CAS, Beijing, 100101, China
- CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China
| | - Jiangpeng Cui
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
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Cui J, Tian L, Gerlein-Safdi C, Qu D. The influence of memory, sample size effects, and filter paper material on online laser-based plant and soil water isotope measurements. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:509-522. [PMID: 28072488 DOI: 10.1002/rcm.7824] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 01/06/2017] [Accepted: 01/07/2017] [Indexed: 06/06/2023]
Abstract
RATIONALE The recent development of isotope ratio infrared spectroscopy (IRIS) was quickly followed by the addition of online extraction and analysis systems, making it faster and easier to measure soil and plant water isotopes. However, memory and sample size effects limit the efficiency and accuracy of these new setups. In response, this study presents a scheme dedicated to estimating and eliminating these two effects. METHODS Memory effect was determined by injecting two standard waters alternately. Each standard was injected nine times in a row and analyzed using induction module cavity ring-down spectroscopy (IM-CRDS). Memory coefficients were calculated using a new "multistage jump" algorithm. Sample size effects were evaluated by injecting water volumes ranging from 1 μL to 6 μL. Finally, the influence of cellulose filter paper on the isotopic measurements, the memory, and the sample size effect was evaluated by comparing it with glass filter paper. RESULTS Memory effects were detected for both δ18 O and δ2 H values, with the latter being stronger. Isotopic differences between replicates of the same plant or soil sample showed a clear decrease after memory correction. A small water volume effect was found only when the injected water volume was larger than 3 μL. However, while the correction method performed well for laboratory-made samples, it did not for field samples, due to the heterogeneity of the isotopic composition of the samples. Stronger memory and water volume effects were found for cellulose filter paper. CONCLUSIONS The memory coefficients and the water volume-isotope relationship improved the consistency and accuracy of both laboratory and field data. Our results indicate that cellulose filter paper may not be a suitable medium to measure standard waters and evaluate memory and water volume effects. Finally, a detailed correction and calibration protocol is suggested, along with notes on best practices to obtain good-quality IM-CRDS data. Copyright © 2017 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jiangpeng Cui
- Key Laboratory of Tibetan Plateau Environment Change and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lide Tian
- Key Laboratory of Tibetan Plateau Environment Change and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
- CAS Centre for Excellence in Tibetan Plateau Earth Sciences, Beijing, 100101, China
| | - Cynthia Gerlein-Safdi
- Department of Civil and Environmental Engineering, Princeton University, Princeton, NJ, 08540, USA
| | - Dongmei Qu
- Key Laboratory of Tibetan Plateau Environment Change and Land Surface Processes, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
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Johnson JE, Hamann L, Dettman DL, Kim-Hak D, Leavitt SW, Monson RK, Papuga SA. Performance of induction module cavity ring-down spectroscopy (IM-CRDS) for measuring δ 18 O and δ 2 H values of soil, stem, and leaf waters. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2017; 31:547-560. [PMID: 28010033 DOI: 10.1002/rcm.7813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2016] [Revised: 12/19/2016] [Accepted: 12/20/2016] [Indexed: 06/06/2023]
Abstract
RATIONALE Induction module cavity ring-down spectroscopy (IM-CRDS) has been proposed as a rapid and cost-effective alternative to cryogenic vacuum distillation (CVD) and isotope ratio mass spectrometry (IRMS) for the measurement of δ18 O and δ2 H values in matrix-bound waters. In the current study, we characterized the performance of IM-CRDS relative to CVD and IRMS and investigated the mechanisms responsible for differences between the methods. METHODS We collected a set of 75 soil, stem, and leaf water samples, and measured the δ18 O and δ2 H values of each sample with four techniques: CVD and IRMS, CVD and CRDS, CVD and IM-CRDS, and IM-CRDS alone. We then calculated the isotopic errors for each of the three CRDS methods relative to CVD and IRMS, and analyzed the relationships among these errors and suites of diagnostic spectral parameters that are indicative of organic contamination. RESULTS The IM-CRDS technique accurately assessed the δ18 O and δ2 H values of pure waters, but exhibited progressively increasing errors for soil waters, stem waters, and leaf waters. For soils, the errors were attributable to subsampling of isotopically heterogeneous source material, whereas for stems and leaves, they were attributable to spectral interference. Unexpectedly, the magnitude of spectral interference was higher for the solid samples analyzed directly via IM-CRDS than for those originally extracted via CVD and then analyzed by IM-CRDS. CONCLUSIONS There are many types of matrix-bound water samples for which IM-CRDS measurements include significant errors from spectral interference. As a result, spectral analysis and validation should be incorporated into IM-CRDS post-processing procedures. In the future, IM-CRDS performance could be improved through: (i) identification of the compounds that cause spectral interference, and either (ii) modification of the combustion step to completely oxidize these compounds to CO2 , and/or (iii) incorporation of corrections for these compounds into the spectral fitting models used by the CRDS analyzers. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- J E Johnson
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Department of Global Ecology, Carnegie Institution, 260 Panama Street, Stanford, CA, 94305, USA
| | - L Hamann
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
| | - D L Dettman
- Department of Geosciences, University of Arizona, Tucson, AZ, 85721, USA
| | - D Kim-Hak
- Picarro, Inc., 3105 Patrick Henry Drive, Santa Clara, CA, 95054, USA
| | - S W Leavitt
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, 85721, USA
| | - R K Monson
- Department of Ecology and Evolutionary Biology, University of Arizona, Tucson, AZ, 85721, USA
- Laboratory of Tree-Ring Research, University of Arizona, Tucson, AZ, 85721, USA
| | - S A Papuga
- School of Natural Resources and the Environment, University of Arizona, Tucson, AZ, 85721, USA
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Volkmann THM, Kühnhammer K, Herbstritt B, Gessler A, Weiler M. A method for in situ monitoring of the isotope composition of tree xylem water using laser spectroscopy. PLANT, CELL & ENVIRONMENT 2016; 39:2055-63. [PMID: 27260852 DOI: 10.1111/pce.12725] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Revised: 01/26/2016] [Accepted: 01/27/2016] [Indexed: 05/27/2023]
Abstract
Field studies analyzing the stable isotope composition of xylem water are providing important information on ecosystem water relations. However, the capacity of stable isotopes to characterize the functioning of plants in their environment has not been fully explored because of methodological constraints on the extent and resolution at which samples could be collected and analysed. Here, we introduce an in situ method offering the potential to continuously monitor the stable isotope composition of tree xylem water via its vapour phase using a commercial laser-based isotope analyser and compact microporous probes installed into the xylem. Our technique enables efficient high-frequency measurement with intervals of only a few minutes per sample while eliminating the need for costly and cumbersome destructive collection of plant material and laboratory-based processing. We present field observations of xylem water hydrogen and oxygen isotope compositions obtained over several days including a labelled irrigation event and compare them against results from concurrent destructive sampling with cryogenic distillation and mass spectrometric analysis. The data demonstrate that temporal changes as well as spatial patterns of integration in xylem water isotope composition can be resolved through direct measurement. The new technique can therefore present a valuable tool to study the hydraulic architecture and water utilization of trees.
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Affiliation(s)
- Till H M Volkmann
- Chair of Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Fahnenbergplatz, 79098, Freiburg, Germany
- Biosphere 2 Earth Science, University of Arizona, 845 N. Park Avenue, Tucson, AZ, 85721, USA
| | - Kathrin Kühnhammer
- Chair of Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Fahnenbergplatz, 79098, Freiburg, Germany
| | - Barbara Herbstritt
- Chair of Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Fahnenbergplatz, 79098, Freiburg, Germany
| | - Arthur Gessler
- Institute for Landscape Biogeochemistry, Leibniz Centre for Agricultural Landscape Research (ZALF), Eberswalder Straße 84, 15374, Müncheberg, Germany
- Research Unit Forest Dynamics, Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), Zürcherstrasse 111, 8903, Birmensdorf, Switzerland
- Berlin-Brandenburg Institute of Advanced Biodiversity Research (BBIB), Altensteinstrasse 6, 14195, Berlin, Germany
| | - Markus Weiler
- Chair of Hydrology, Faculty of Environment and Natural Resources, University of Freiburg, Fahnenbergplatz, 79098, Freiburg, Germany
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Martín-Gómez P, Barbeta A, Voltas J, Peñuelas J, Dennis K, Palacio S, Dawson TE, Ferrio JP. Isotope-ratio infrared spectroscopy: a reliable tool for the investigation of plant-water sources? THE NEW PHYTOLOGIST 2015; 207:914-27. [PMID: 25790288 DOI: 10.1111/nph.13376] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2014] [Accepted: 02/11/2015] [Indexed: 05/16/2023]
Abstract
Stable isotopes are extensively used as tracers for the study of plant-water sources. Isotope-ratio infrared spectroscopy (IRIS) offers a cheaper alternative to isotope-ratio mass spectroscopy (IRMS), but its use in studying plant and soil water is limited by the spectral interference caused by organic contaminants. Here, we examine two approaches to cope with contaminated samples in IRIS: on-line oxidation of organic compounds (MCM) and post-processing correction. We assessed these methods compared to IRMS across 136 samples of xylem and soil water, and a set of ethanol- and methanol-water mixtures. A post-processing correction significantly improved IRIS accuracy in both natural samples and alcohol dilutions, being effective with concentrations up to 8% of ethanol and 0.4% of methanol. MCM outperformed the post-processing correction in removing methanol interference, but did not effectively remove interference for high concentrations of ethanol. By using both approaches, IRIS can overcome with reasonable accuracy the analytical uncertainties associated with most organic contaminants found in soil and xylem water. We recommend the post-processing correction as the first choice for analysis of samples of unknown contamination. Nevertheless, MCM can be more effective for evaluating samples containing contaminants responsible for strong spectral interferences at low concentrations, such as methanol.
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Affiliation(s)
- Paula Martín-Gómez
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, Lleida, E-25198, Spain
| | - Adrià Barbeta
- Global Ecology Unit CREAF-CSIC-UAB, CSIC, Cerdanyola del Valles (Catalonia), E-08193, Spain
- CREAF, Cerdanyola del Vallès (Catalonia), E-08193, Spain
| | - Jordi Voltas
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, Lleida, E-25198, Spain
| | - Josep Peñuelas
- Global Ecology Unit CREAF-CSIC-UAB, CSIC, Cerdanyola del Valles (Catalonia), E-08193, Spain
- CREAF, Cerdanyola del Vallès (Catalonia), E-08193, Spain
| | - Kate Dennis
- Product Manager for Isotopic Water, Picarro Inc., Santa Clara, CA, 95054, USA
| | - Sara Palacio
- Instituto Pirenaico de Ecología (IPE-CSIC), Jaca, E-22700, Spain
| | - Todd E Dawson
- Department of Integrative Biology, University of California, Berkeley, CA, 94720, USA
| | - Juan Pedro Ferrio
- Department of Crop and Forest Sciences-AGROTECNIO Center, Universitat de Lleida, Lleida, E-25198, Spain
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Skrzypek G, Ford D. Stable isotope analysis of saline water samples on a cavity ring-down spectroscopy instrument. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:2827-2834. [PMID: 24528490 DOI: 10.1021/es4049412] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The analysis of the stable hydrogen and oxygen isotope composition of water using cavity ring-down spectroscopy (CRDS) instruments utilizing infrared absorption spectroscopy have been comprehensively tested. However, potential limitations of infrared spectroscopy for the analysis of highly saline water have not yet been evaluated. In this study, we assessed uncertainty arising from elevated salt concentrations in water analyzed on a CRDS instrument and the necessity of a correction procedure. We prepared various solutions of mixed salts and separate solutions with individual salts (NaCl, KCl, MgCl2, and CaCl2) using deionized water with a known stable isotope composition. Most of the individual salt and salt mixture solutions (some up to 340 g L(-1)) had δ-values within the range usual for CRDS analytical uncertainty (0.1‰ for δ (18)O and 1.0‰ for δ (2)H). Results were not compromised even when the total load of salt in the vaporizer reached ∼38.5 mg (equivalent to build up after running ∼100 ocean water samples). Therefore, highly saline mixtures can be successfully analyzed using CRDS, except highly concentrated MgCl2 solutions, without the need for an additional correction if the vaporizer is frequently cleaned and MgCl2 concentration in water is relatively low.
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Affiliation(s)
- Grzegorz Skrzypek
- West Australian Biogeochemistry Centre, School of Plant Biology, The University of Western Australia , MO90, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
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Wassenaar LI, Coplen TB, Aggarwal PK. Approaches for achieving long-term accuracy and precision of δ18O and δ2H for waters analyzed using laser absorption spectrometers. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:1123-1131. [PMID: 24328223 DOI: 10.1021/es403354n] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The measurement of δ(2)H and δ(18)O in water samples by laser absorption spectroscopy (LAS) are adopted increasingly in hydrologic and environmental studies. Although LAS instrumentation is easy to use, its incorporation into laboratory operations is not as easy, owing to extensive offline data manipulation required for outlier detection, derivation and application of algorithms to correct for between-sample memory, correcting for linear and nonlinear instrumental drift, VSMOW-SLAP scale normalization, and in maintaining long-term QA/QC audits. Here we propose a series of standardized water-isotope LAS performance tests and routine sample analysis templates, recommended procedural guidelines, and new data processing software (LIMS for Lasers) that altogether enables new and current LAS users to achieve and sustain long-term δ(2)H and δ(18)O accuracy and precision for these important isotopic assays.
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Affiliation(s)
- Leonard I Wassenaar
- Isotope Hydrology Section, International Atomic Energy Agency , Vienna International Center, Vienna, Austria , A-1400
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Arienzo MM, Swart PK, Vonhof HB. Measurement of δ18O and δ2H values of fluid inclusion water in speleothems using cavity ring-down spectroscopy compared with isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2013; 27:2616-2624. [PMID: 24591022 DOI: 10.1002/rcm.6723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2013] [Revised: 08/13/2013] [Accepted: 08/26/2013] [Indexed: 06/03/2023]
Abstract
RATIONALE The hydrogen and oxygen isotopic analyses (δ(2)H and δ(18)O values) of water trapped within speleothem carbonate (fluid inclusions) have traditionally been conducted utilizing dual-inlet isotope ratio mass spectrometry (IRMS) or continuous-flow (CF)-IRMS methods. The application of cavity ring-down spectroscopy (CRDS) to the δ(2)H and δ(18)O analysis of water in fluid inclusions has been investigated at the University of Miami as an alternative method to CF-IRMS. METHODS An extraction line was developed to recover water from the fluid inclusions consisting of a crusher, sample injection port and an expansion volume (either 100 or 50 cm(3)) directly connected to the CRDS instrument. Tests were conducted to determine the reproducibility of standard water injections and crushes. In order to compare results with conventional analytical methods, samples were analyzed both at the University of Miami (CRDS method) and at the Vrije Universiteit Amsterdam (CF-IRMS method). RESULTS The analytical reproducibility of speleothem samples crushed on the Miami Device demonstrates an average external standard deviation of 0.5 and 2.0 ‰ for δ(18)O and δ(2)H values, respectively. Sample data are shown to fall near the global meteoric water line, supporting the validity of the method. Three different samples were analyzed at Vrije Universiteit Amsterdam and the University of Miami in order to compare the performance of each laboratory. The average offset between the two laboratories is 0.7 ‰ for δ(18)O and 2.5 ‰ for δ(2)H. CONCLUSIONS The advantage of CRDS is that the system is a low-cost alternative to CF-IRMS for fluid inclusion isotope analysis. The CRDS method demonstrates acceptable precision and good agreement with results from the CF-IRMS method. These are promising results for the future application of CRDS to fluid inclusion isotope analysis.
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Affiliation(s)
- Monica M Arienzo
- RSMAS, University of Miami, Marine Geology and Geophysics, 4600 Rickenbacker Causeway, Miami, FL, 33149, USA
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