1
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Greule M, Le PM, Meija J, Mester Z, Keppler F. Comparison of Carbon Isotope Ratio Measurement of the Vanillin Methoxy Group by GC-IRMS and 13C-qNMR. J Am Soc Mass Spectrom 2024; 35:100-105. [PMID: 38015023 PMCID: PMC10767744 DOI: 10.1021/jasms.3c00327] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/29/2023]
Abstract
Site-specific carbon isotope ratio measurements by quantitative 13C NMR (13C-qNMR), Orbitrap-MS, and GC-IRMS offer a new dimension to conventional bulk carbon isotope ratio measurements used in food provenance, forensics, and a number of other applications. While the site-specific measurements of carbon isotope ratios in vanillin by 13C-qNMR or Orbitrap-MS are powerful new tools in food analysis, there are a limited number of studies regarding the validity of these measurement results. Here we present carbon site-specific measurements of vanillin by GC-IRMS and 13C-qNMR for methoxy carbon. Carbon isotope delta (δ13C) values obtained by these different measurement approaches demonstrate remarkable agreement; in five vanillin samples whose bulk δ13C values ranged from -31‰ to -26‰, their δ13C values of the methoxy carbon ranged from -62.4‰ to -30.6‰, yet the difference between the results of the two analytical approaches was within ±0.6‰. While the GC-IRMS approach afforded up to 9-fold lower uncertainties and required 100-fold less sample compared to the 13C-qNMR, the 13C-qNMR is able to assign δ13C values to all carbon atoms in the molecule, not just the cleavable methoxy group.
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Affiliation(s)
- Markus Greule
- Institute
of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Phuong Mai Le
- Metrology, National
Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A
0R6, Canada
| | - Juris Meija
- Metrology, National
Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A
0R6, Canada
| | - Zoltán Mester
- Metrology, National
Research Council Canada, 1200 Montreal Road, Ottawa, ON K1A
0R6, Canada
| | - Frank Keppler
- Institute
of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
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2
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Schroll M, Liu L, Einzmann T, Keppler F, Grossart HP. Methane accumulation and its potential precursor compounds in the oxic surface water layer of two contrasting stratified lakes. Sci Total Environ 2023; 903:166205. [PMID: 37567306 DOI: 10.1016/j.scitotenv.2023.166205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 08/08/2023] [Accepted: 08/08/2023] [Indexed: 08/13/2023]
Abstract
Methane (CH4) supersaturation in oxygenated waters is a widespread phenomenon despite the traditional perception of strict anoxic methanogenesis. This notion has recently been challenged by successive findings of processes and mechanisms that produce CH4 in oxic environments. While some of the processes contributing to the vertical accumulation of CH4 in the oxygenated upper water layers of freshwater lakes have been identified, temporal variations as well as drivers are still poorly understood. In this study, we investigated the accumulation of CH4 in oxic water layers of two contrasting lakes in Germany: Lake Willersinnweiher (shallow, monomictic, eutrophic) and Lake Stechlin (deep, dimictic, eutrophic) from 2019 to 2020. The dynamics of isotopic values of CH4 and the role of potential precursor compounds of oxic CH4 production were explored. During the study period, persistent strong CH4 supersaturation (relative to air) was observed in the surface waters, mostly concentrated around the thermocline. The magnitude of vertical CH4 accumulation strongly varied over season and was generally more pronounced in shallow Lake Willersinnweiher. In both lakes, increases in CH4 concentrations from the surface to the thermocline mostly coincided with an enrichment in 13C-CH4 and 2H-CH4, indicating a complex interaction of multiple processes such as CH4 oxidation, CH4 transport from littoral sediments and oxic CH4 production, sustaining and controlling this CH4 supersaturation. Furthermore, incubation experiments with 13C- and 2H-labelled methylated P-, N- and C- compounds clearly showed that methylphosphonate, methylamine and methionine acted as potent precursors of accumulating CH4 and at least partly sustained CH4 supersaturation. This highlights the need to better understand the mechanisms underlying CH4 accumulation by focusing on production and transport pathways of CH4 and its precursor compounds, e.g., produced via phytoplankton. Such knowledge forms the foundation to better predict aquatic CH4 dynamics and its subsequent rates of emission to the atmosphere.
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Affiliation(s)
- Moritz Schroll
- Laboratory of Plateau Geographical Processes and Environmental Changes, Faculty of Geography, Yunnan Normal University, 650500 Kunming, China; Institute of Earth Sciences, Heidelberg University, 69120 Heidelberg, Germany.
| | - Liu Liu
- Laboratory of Plateau Geographical Processes and Environmental Changes, Faculty of Geography, Yunnan Normal University, 650500 Kunming, China; Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, 16775 Stechlin, Germany.
| | - Teresa Einzmann
- Institute of Earth Sciences, Heidelberg University, 69120 Heidelberg, Germany; Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, 69120 Heidelberg, Germany; Heidelberg Center for the Environment (HCE), Heidelberg University, 69120 Heidelberg, Germany
| | - Hans-Peter Grossart
- Department of Plankton and Microbial Ecology, Leibniz Institute of Freshwater Ecology and Inland Fisheries, 16775 Stechlin, Germany; Institute of Biochemistry and Biology, Potsdam University, 14476 Potsdam, Germany
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3
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Hädeler J, Velmurugan G, Lauer R, Radhamani R, Keppler F, Comba P. Natural Abiotic Iron-Oxido-Mediated Formation of C 1 and C 2 Compounds from Environmentally Important Methyl-Substituted Substrates. J Am Chem Soc 2023. [PMID: 37930326 DOI: 10.1021/jacs.3c06709] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Organic and inorganic volatile compounds containing one carbon atom (C1), such as carbon dioxide, methane, methanol, formaldehyde, carbon monoxide, and chloromethane, are ubiquitous in the environment, are key components in global carbon cycling, play an important role in atmospheric physics and chemistry, e.g., as greenhouse gases, destroy stratospheric and tropospheric ozone, and control the atmospheric oxidation capacity. Up to now, most C1 compounds in the environment were associated with complex metabolic and enzymatic pathways in organisms or to combustion processes of organic matter. We now present compelling evidence that many C1 and C2 compounds have a common origin in methyl groups of methyl-substituted substrates that are cleaved by the iron oxide-mediated formation of methyl radicals. This scenario is derived from experiments with a mechanistically well-studied bispidine-iron-oxido complex as oxidant and dimethyl sulfoxide as the environmentally relevant model substrate and is supported by computational modeling based on density functional theory and ab initio quantum-chemical studies. The exhaustive experimental model studies, also involving extensive isotope labeling, are complemented with the substitution of the bispidine model system by environmentally relevant iron oxides and, finally, a collection of soils with varying iron and organic matter contents. The combination of all data suggests that the iron oxide-mediated formation of methyl radicals from methyl-substituted substrates is a common abiotic source for widespread C1 and C2 compounds in the environment.
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Affiliation(s)
- Jonas Hädeler
- Institut für Geowissenschaften, INF 234-236, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Gunasekaran Velmurugan
- Anorganisch-Chemisches Institut INF 270, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Rebekka Lauer
- Institut für Geowissenschaften, INF 234-236, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Rejith Radhamani
- Anorganisch-Chemisches Institut INF 270, Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Frank Keppler
- Institut für Geowissenschaften, INF 234-236, Universität Heidelberg, D-69120 Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Universität Heidelberg, D-69120 Heidelberg, Germany
| | - Peter Comba
- Anorganisch-Chemisches Institut INF 270, Universität Heidelberg, D-69120 Heidelberg, Germany
- Interdisciplinary Center for Scientific Computing, INF 205, Universität Heidelberg, D-69120 Heidelberg, Germany
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4
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Ernst L, Barayeu U, Hädeler J, Dick TP, Klatt JM, Keppler F, Rebelein JG. Methane formation driven by light and heat prior to the origin of life and beyond. Nat Commun 2023; 14:4364. [PMID: 37528079 PMCID: PMC10394037 DOI: 10.1038/s41467-023-39917-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 07/03/2023] [Indexed: 08/03/2023] Open
Abstract
Methane is a potent greenhouse gas, which likely enabled the evolution of life by keeping the early Earth warm. Here, we demonstrate routes towards abiotic methane and ethane formation under early-earth conditions from methylated sulfur and nitrogen compounds with prebiotic origin. These compounds are demethylated in Fenton reactions governed by ferrous iron and reactive oxygen species (ROS) produced by light and heat in aqueous environments. After the emergence of life, this phenomenon would have greatly intensified in the anoxic Archean by providing methylated sulfur and nitrogen substrates. This ROS-driven Fenton chemistry can occur delocalized from serpentinization across Earth's humid realm and thereby substantially differs from previously suggested methane formation routes that are spatially restricted. Here, we report that Fenton reactions driven by light and heat release methane and ethane and might have shaped the chemical evolution of the atmosphere prior to the origin of life and beyond.
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Affiliation(s)
- Leonard Ernst
- Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.
- Center for Synthetic Microbiology (SYNMIKRO), 35032, Marburg, Germany.
| | - Uladzimir Barayeu
- Division of Redox Regulation, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Jonas Hädeler
- Institute of Earth Sciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Tobias P Dick
- Division of Redox Regulation, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, 69120, Heidelberg, Germany
- Faculty of Biosciences, Heidelberg University, 69120, Heidelberg, Germany
| | - Judith M Klatt
- Center for Synthetic Microbiology (SYNMIKRO), 35032, Marburg, Germany
- Microcosm Earth Center, Max Planck Institute for Terrestrial Microbiology & Philipps University Marburg, 35032, Marburg, Germany
- Biogeochemistry Group, Department for Chemistry, Philipps University Marburg, 35032, Marburg, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, 69120, Heidelberg, Germany
- Heidelberg Center for the Environment HCE, Heidelberg University, 69120, Heidelberg, Germany
| | - Johannes G Rebelein
- Max Planck Institute for Terrestrial Microbiology, 35043, Marburg, Germany.
- Center for Synthetic Microbiology (SYNMIKRO), 35032, Marburg, Germany.
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5
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Polag D, Keppler F. Effect of immune responses on breath methane dynamics. J Breath Res 2023. [PMID: 37487488 DOI: 10.1088/1752-7163/ace9f2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/26/2023]
Abstract
Methane (CH4) which can be detected in human breath has long been exclusively associated with anaerobic microbial activity (methanogenesis) in the gastrointestinal tract. However, recent studies challenge this understanding by revealing that CH4 might also be produced endogenously in cells through oxidative-reductive stress reactions. Consequently, variations in breath CH4 levels compared to an individual's baseline level might indicate enhanced oxidative stress levels, and, therefore, monitoring breath CH4 levels might offer great potential for "'in vivo" diagnostics such as disease diagnosis, monitoring the efficacy of treatments, or during the application of personalized medicine.
To evaluate the effects from immune responses triggered by infections, inflammations, and induced perturbation by vaccination on CH4 dynamics in breath, two subjects were monitored over a period of almost two years. Breath CH4 levels were measured by gas chromatography equipped with a flame-ionization detector. Both subjects exhibited significant deviations (positive and negative, respectively) from their normal CH4 breath levels during periods of potential enhanced immune activity. Deviations from the "'healthy state" were indicated by the exceeding of individual CH4 ranges. Moreover, for the first time we could clearly prove CH4 degradation induced through vaccination by measuring stable carbon isotopes of CH4 using gas chromatograph - combustion - isotope ratio mass spectrometry. Hence, breath CH4 concentration and isotopic analyses may be used as a biomarker to evaluate specific immune responses and individual immune states.
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Affiliation(s)
- Daniela Polag
- Insitute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Baden-Württemberg, 69117, GERMANY
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Baden-Württemberg, 69117, GERMANY
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6
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Keppler F, Boros M, Polag D. Radical-Driven Methane Formation in Humans Evidenced by Exogenous Isotope-Labeled DMSO and Methionine. Antioxidants (Basel) 2023; 12:1381. [PMID: 37507920 PMCID: PMC10376501 DOI: 10.3390/antiox12071381] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/29/2023] [Accepted: 07/01/2023] [Indexed: 07/30/2023] Open
Abstract
Methane (CH4), which is produced endogenously in animals and plants, was recently suggested to play a role in cellular physiology, potentially influencing the signaling pathways and regulatory mechanisms involved in nitrosative and oxidative stress responses. In addition, it was proposed that the supplementation of CH4 to organisms may be beneficial for the treatment of several diseases, including ischemia, reperfusion injury, and inflammation. However, it is still unclear whether and how CH4 is produced in mammalian cells without the help of microorganisms, and how CH4 might be involved in physiological processes in humans. In this study, we produced the first evidence of the principle that CH4 is formed non-microbially in the human body by applying isotopically labeled methylated sulfur compounds, such as dimethyl sulfoxide (DMSO) and methionine, as carbon precursors to confirm cellular CH4 formation. A volunteer applied isotopically labeled (2H and 13C) DMSO on the skin, orally, and to blood samples. The monitoring of stable isotope values of CH4 convincingly showed the conversion of the methyl groups, as isotopically labeled CH4 was formed during all experiments. Based on these results, we considered several hypotheses about endogenously formed CH4 in humans, including physiological aspects and stress responses involving reactive oxygen species (ROS). While further and broader validation studies are needed, the results may unambiguously serve as a proof of concept for the endogenous formation of CH4 in humans via a radical-driven process. Furthermore, these results might encourage follow-up studies to decipher the potential physiological role of CH4 and its bioactivity in humans in more detail. Of particular importance is the potential to monitor CH4 as an oxidative stress biomarker if the observed large variability of CH4 in breath air is an indicator of physiological stress responses and immune reactions. Finally, the potential role of DMSO as a radical scavenger to counteract oxidative stress caused by ROS might be considered in the health sciences. DMSO has already been investigated for many years, but its potential positive role in medical use remains highly uncertain.
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Affiliation(s)
- Frank Keppler
- Institute of Earth Sciences, Heidelberg University, D-69120 Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg University, D-69120 Heidelberg, Germany
| | - Mihály Boros
- Institute of Surgical Research, University of Szeged, H-6724 Szeged, Hungary
| | - Daniela Polag
- Institute of Earth Sciences, Heidelberg University, D-69120 Heidelberg, Germany
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7
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Reinig F, Wacker L, Jöris O, Oppenheimer C, Guidobaldi G, Nievergelt D, Adolphi F, Cherubini P, Engels S, Esper J, Keppler F, Land A, Lane C, Pfanz H, Remmele S, Sigl M, Sookdeo A, Büntgen U. Reply to: Possible magmatic CO 2 influence on the Laacher See eruption date. Nature 2023; 619:E3-E8. [PMID: 37407681 DOI: 10.1038/s41586-023-05966-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/07/2023]
Affiliation(s)
- Frederick Reinig
- Department of Geography, Johannes Gutenberg University, Mainz, Germany.
| | - Lukas Wacker
- Laboratory of Ion Beam Physics, ETH Zurich, Zurich, Switzerland
| | - Olaf Jöris
- Leibniz-Zentrum für Archäologie-MONREPOS Archaeological Research Centre and Museum for Human Behavioural Evolution, Neuwied, Germany
- Institute of Ancient Studies, Department of Prehistoric and Protohistoric Archaeology, Johannes Gutenberg University, Mainz, Germany
- Key Laboratory of Western China's Environmental Systems (Ministry of Education), College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, China
| | | | - Giulia Guidobaldi
- Forest Dynamics/Dendrosciences, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Daniel Nievergelt
- Forest Dynamics/Dendrosciences, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
| | - Florian Adolphi
- Alfred Wegener Institute, Helmholtz Center for Polar and Marine Research, Bremerhaven, Germany
- Department of Geosciences, University of Bremen, Bremen, Germany
| | - Paolo Cherubini
- Forest Dynamics/Dendrosciences, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- Department of Forest and Conservation Sciences, University of British Columbia, Vancouver, British Columbia, Canada
| | - Stefan Engels
- Department of Geography, Birkbeck University of London, London, UK
| | - Jan Esper
- Department of Geography, Johannes Gutenberg University, Mainz, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
- Heidelberg Center for the Environment, Heidelberg University, Heidelberg, Germany
| | - Alexander Land
- Institute of Biology (190a), University of Hohenheim, Stuttgart, Germany
- Silviculture & Forest Growth and Yield, University of Applied Forest Sciences, Rottenburg am Neckar, Germany
| | - Christine Lane
- Department of Geography, University of Cambridge, Cambridge, UK
| | - Hardy Pfanz
- Institute of Applied Botanics and Volcanic Biology, Universität Duisburg-Essen, Essen, Germany
| | - Sabine Remmele
- Institute of Biology (190a), University of Hohenheim, Stuttgart, Germany
| | - Michael Sigl
- Climate and Environmental Physics, Physics Institute, Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland
| | - Adam Sookdeo
- Laboratory of Ion Beam Physics, ETH Zurich, Zurich, Switzerland
| | - Ulf Büntgen
- Department of Geography, University of Cambridge, Cambridge, UK
- Forest Dynamics/Dendrosciences, Swiss Federal Research Institute WSL, Birmensdorf, Switzerland
- Global Change Research Institute of the Czech Academy of Sciences (CzechGlobe), Brno, Czech Republic
- Department of Geography, Faculty of Science, Masaryk University, Brno, Czech Republic
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8
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Schorndorf N, Frank N, Ritter SM, Warken SF, Scholz C, Keppler F, Scholz D, Weber M, Aviles Olguin J, Stinnesbeck W. Mid- to late Holocene sea-level rise recorded in Hells Bells 234U/ 238U ratio and geochemical composition. Sci Rep 2023; 13:10011. [PMID: 37340006 DOI: 10.1038/s41598-023-36777-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 06/09/2023] [Indexed: 06/22/2023] Open
Abstract
Hells Bells are underwater secondary carbonates discovered in sinkholes (cenotes) southeast of Cancun on the north-eastern Yucatán peninsula, Mexico. These authigenic calcite precipitates, reaching a length of up to 4 m, most likely grow in the pelagic redoxcline. Here we report on detailed 230Th/U-dating and in-depth geochemical and stable isotope analyses of specimens from cenotes El Zapote, Maravilla and Tortugas. Hells Bells developed since at least ~ 8000 years ago, with active growth until present day. Initial (234U/238U) activity ratios (δ234U0) in Hells Bells calcite decreas from 55 to 15‰ as sea level converges toward its present state. The temporal evolution of the geochemistry and isotope composition of Hells Bells calcites thus appears to be closely linked to sea-level rise and reflects changing hydrological conditions (desalinization) of the aquifer. We suggest that decelerated leaching of excess 234U from the previously unsaturated bedrock traces Holocene relative sea-level rise. Considering this proxy, the resulting mean sea-level reconstruction contains half as much scatter, i.e. improves by a factor of two, when compared to previously published work for the period between 8 and 4 ky BP.
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Affiliation(s)
- Nils Schorndorf
- Institute of Earth Sciences, Heidelberg, Germany.
- Institute of Environmental Physics, Heidelberg, Germany.
| | - Norbert Frank
- Institute of Earth Sciences, Heidelberg, Germany
- Institute of Environmental Physics, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg, Germany
| | | | - Sophie F Warken
- Institute of Earth Sciences, Heidelberg, Germany
- Institute of Environmental Physics, Heidelberg, Germany
| | | | - Frank Keppler
- Institute of Earth Sciences, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg, Germany
| | | | | | | | - Wolfgang Stinnesbeck
- Institute of Earth Sciences, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg, Germany
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9
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Keppler F, Ernst L, Polag D, Zhang J, Boros M. ROS-driven cellular methane formation: Potential implications for health sciences. Clin Transl Med 2022; 12:e905. [PMID: 35839303 PMCID: PMC9286325 DOI: 10.1002/ctm2.905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 05/15/2022] [Indexed: 11/08/2022] Open
Abstract
Recently it has been proposed that methane might be produced by all living organisms via a mechanism driven by reactive oxygen species that arise through the metabolic activity of cells. Here, we summarise details of this novel reaction pathway and discuss its potential significance for clinical and health sciences. In particular, we highlight the role of oxidative stress in cellular methane formation. As several recent studies also demonstrated the anti-inflammatory potential for exogenous methane-based approaches in mammalians, this article addresses the intriguing question if ROS-driven methane formation has a general physiological role and associated diagnostic potential.
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Affiliation(s)
- Frank Keppler
- Biogeochemistry Group, Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany.,Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany
| | - Leonard Ernst
- Biogeochemistry Group, Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany
| | - Daniela Polag
- Biogeochemistry Group, Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
| | - Jingyao Zhang
- Department of Hepatobiliary Surgery and Department of SICU, The First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, China
| | - Mihaly Boros
- Institute of Surgical Research and Interdisciplinary Excellence Centre, University of Szeged, Szeged, Hungary
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10
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Schroll M, Lenhart K, Greiner S, Keppler F. Making plant methane formation visible-Insights from application of 13C-labeled dimethyl sulfoxide. Plant Environ Interact 2022; 3:104-117. [PMID: 37284426 PMCID: PMC10168057 DOI: 10.1002/pei3.10076] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 04/06/2022] [Accepted: 04/15/2022] [Indexed: 06/08/2023]
Abstract
Methane (CH4) formation by vegetation has been studied intensively over the last 15 years. However, reported CH4 emissions vary by several orders of magnitude, thus making global estimates difficult. Moreover, the mechanism(s) for CH4 formation by plants is (are) largely unknown.Here, we introduce a new approach for making CH4 formation by plants clearly visible. By application of 13C-labeled dimethyl sulfoxide (DMSO) onto the leaves of tobacco plants (Nicotiana tabacum) and Chinese silver grass (Miscanthus sinensis) the effect of light and dark conditions on CH4 formation of this pathway was examined by monitoring stable carbon isotope ratios of headspace CH4 (δ13C-CH4 values).Both plant species showed increasing headspace δ13C-CH4 values while exposed to light. Higher light intensities increased CH4 formation rates in N. tabacum but decreased rates for M. sinensis. In the dark no formation of CH4 could be detected for N. tabacum, while M. sinensis still produced ~50% of CH4 compared to that during light exposure.Our findings suggest that CH4 formation is clearly dependent on light conditions and plant species and thus indicate that DMSO is a potential precursor of vegetative CH4. The novel isotope approach has great potential to investigate, at high temporal resolution, physiological, and environmental factors that control pathway-specific CH4 emissions from plants.
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Affiliation(s)
- Moritz Schroll
- Institute of Earth SciencesHeidelberg UniversityHeidelbergGermany
| | - Katharina Lenhart
- Bingen University of Applied SciencesBingenGermany
- Center for Organismal Studies (COS)HeidelbergGermany
| | | | - Frank Keppler
- Institute of Earth SciencesHeidelberg UniversityHeidelbergGermany
- Heidelberg Center for the Environment (HCE)Heidelberg UniversityHeidelbergGermany
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11
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Ernst L, Steinfeld B, Barayeu U, Klintzsch T, Kurth M, Grimm D, Dick TP, Rebelein JG, Bischofs IB, Keppler F. Methane formation driven by reactive oxygen species across all living organisms. Nature 2022; 603:482-487. [PMID: 35264795 DOI: 10.1038/s41586-022-04511-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2021] [Accepted: 02/03/2022] [Indexed: 11/09/2022]
Abstract
Methane (CH4), the most abundant hydrocarbon in the atmosphere, originates largely from biogenic sources1 linked to an increasing number of organisms occurring in oxic and anoxic environments. Traditionally, biogenic CH4 has been regarded as the final product of anoxic decomposition of organic matter by methanogenic archaea. However, plants2,3, fungi4, algae5 and cyanobacteria6 can produce CH4 in the presence of oxygen. Although methanogens are known to produce CH4 enzymatically during anaerobic energy metabolism7, the requirements and pathways for CH4 production by non-methanogenic cells are poorly understood. Here, we demonstrate that CH4 formation by Bacillus subtilis and Escherichia coli is triggered by free iron and reactive oxygen species (ROS), which are generated by metabolic activity and enhanced by oxidative stress. ROS-induced methyl radicals, which are derived from organic compounds containing sulfur- or nitrogen-bonded methyl groups, are key intermediates that ultimately lead to CH4 production. We further show CH4 production by many other model organisms from the Bacteria, Archaea and Eukarya domains, including in several human cell lines. All these organisms respond to inducers of oxidative stress by enhanced CH4 formation. Our results imply that all living cells probably possess a common mechanism of CH4 formation that is based on interactions among ROS, iron and methyl donors, opening new perspectives for understanding biochemical CH4 formation and cycling.
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Affiliation(s)
- Leonard Ernst
- BioQuant Center, Heidelberg University, Heidelberg, Germany. .,Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany. .,Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany.
| | - Benedikt Steinfeld
- BioQuant Center, Heidelberg University, Heidelberg, Germany.,Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany.,Zentrum für Molekulare Biologie Heidelberg (ZMBH), Heidelberg University, Heidelberg, Germany
| | - Uladzimir Barayeu
- Division of Redox Regulation, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | - Thomas Klintzsch
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany.,Department for Plant Nutrition, Gießen University, Gießen, Germany
| | - Markus Kurth
- Heidelberg Institute for Theoretical Studies, Heidelberg, Germany
| | - Dirk Grimm
- BioQuant Center, Heidelberg University, Heidelberg, Germany.,Department of Infectious Diseases/Virology, Medical Faculty, Heidelberg University, Heidelberg, Germany
| | - Tobias P Dick
- Division of Redox Regulation, German Cancer Research Center (DKFZ), DKFZ-ZMBH Alliance, Heidelberg, Germany.,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany
| | | | - Ilka B Bischofs
- BioQuant Center, Heidelberg University, Heidelberg, Germany. .,Max-Planck-Institute for Terrestrial Microbiology, Marburg, Germany. .,Faculty of Biosciences, Heidelberg University, Heidelberg, Germany.
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany. .,Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany.
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12
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Abstract
[Figure: see text].
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Affiliation(s)
- Frank Keppler
- Biogeochemistry Group, Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany.,Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany
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13
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Kröber E, Wende S, Kanukollu S, Buchen-Tschiskale C, Besaury L, Keppler F, Vuilleumier S, Kolb S, Bringel F. 13 C-chloromethane incubations provide evidence for novel bacterial chloromethane degraders in a living tree fern. Environ Microbiol 2021. [PMID: 34121306 DOI: 10.1111/1562-2920.15638] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Chloromethane (CH3 Cl) is the most abundant halogenated volatile organic compound in the atmosphere and contributes to stratospheric ozone depletion. CH3 Cl has mainly natural sources such as emissions from vegetation. In particular, ferns have been recognized as strong emitters. Mitigation of CH3 Cl to the atmosphere by methylotrophic bacteria, a global sink for this compound, is likely underestimated and remains poorly characterized. We identified and characterized CH3 Cl-degrading bacteria associated with intact and living tree fern plants of the species Cyathea australis by stable isotope probing (SIP) with 13 C-labelled CH3 Cl combined with metagenomics. Metagenome-assembled genomes (MAGs) related to Methylobacterium and Friedmanniella were identified as being involved in the degradation of CH3 Cl in the phyllosphere, i.e., the aerial parts of the tree fern, while a MAG related to Sorangium was linked to CH3 Cl degradation in the fern rhizosphere. The only known metabolic pathway for CH3 Cl degradation, via a methyltransferase system including the gene cmuA, was not detected in metagenomes or MAGs identified by SIP. Hence, a yet uncharacterized methylotrophic cmuA-independent pathway may drive CH3 Cl degradation in the investigated tree ferns.
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Affiliation(s)
- Eileen Kröber
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Sonja Wende
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Saranya Kanukollu
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Caroline Buchen-Tschiskale
- Isotope Biogeochemistry and Gas Fluxes, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Ludovic Besaury
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
| | - Stéphane Vuilleumier
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
| | - Steffen Kolb
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
- Thaer Institute, Faculty of Life Sciences, Humboldt University of Berlin, Berlin, Germany
| | - Françoise Bringel
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
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14
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Kröber E, Wende S, Kanukollu S, Buchen-Tschiskale C, Besaury L, Keppler F, Vuilleumier S, Kolb S, Bringel F. 13 C-chloromethane incubations provide evidence for novel bacterial chloromethane degraders in a living tree fern. Environ Microbiol 2021; 23:4450-4465. [PMID: 34121306 DOI: 10.1111/1462-2920.15638] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/08/2021] [Accepted: 06/09/2021] [Indexed: 12/20/2022]
Abstract
Chloromethane (CH3 Cl) is the most abundant halogenated volatile organic compound in the atmosphere and contributes to stratospheric ozone depletion. CH3 Cl has mainly natural sources such as emissions from vegetation. In particular, ferns have been recognized as strong emitters. Mitigation of CH3 Cl to the atmosphere by methylotrophic bacteria, a global sink for this compound, is likely underestimated and remains poorly characterized. We identified and characterized CH3 Cl-degrading bacteria associated with intact and living tree fern plants of the species Cyathea australis by stable isotope probing (SIP) with 13 C-labelled CH3 Cl combined with metagenomics. Metagenome-assembled genomes (MAGs) related to Methylobacterium and Friedmanniella were identified as being involved in the degradation of CH3 Cl in the phyllosphere, i.e., the aerial parts of the tree fern, while a MAG related to Sorangium was linked to CH3 Cl degradation in the fern rhizosphere. The only known metabolic pathway for CH3 Cl degradation, via a methyltransferase system including the gene cmuA, was not detected in metagenomes or MAGs identified by SIP. Hence, a yet uncharacterized methylotrophic cmuA-independent pathway may drive CH3 Cl degradation in the investigated tree ferns.
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Affiliation(s)
- Eileen Kröber
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Sonja Wende
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Saranya Kanukollu
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Caroline Buchen-Tschiskale
- Isotope Biogeochemistry and Gas Fluxes, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany
| | - Ludovic Besaury
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
| | - Stéphane Vuilleumier
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
| | - Steffen Kolb
- Microbial Biogeochemistry, RA Landscape Functioning, ZALF Leibniz Centre for Agricultural Landscape Research, Müncheberg, Germany.,Thaer Institute, Faculty of Life Sciences, Humboldt University of Berlin, Berlin, Germany
| | - Françoise Bringel
- Génétique Moléculaire, Génomique, Microbiologie (GMGM), Université de Strasbourg, UMR 7156 CNRS, Strasbourg, France
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15
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Wang Y, Liu X, Anhäuser T, Lu Q, Zeng X, Zhang Q, Wang K, Zhang L, Zhang Y, Keppler F. Temperature signal recorded in δ 2H and δ 13C values of wood lignin methoxyl groups from a permafrost forest in northeastern China. Sci Total Environ 2020; 727:138558. [PMID: 32498208 DOI: 10.1016/j.scitotenv.2020.138558] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/04/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Stable isotopes in wood lignin methoxyl groups (δ2HLM and δ13CLM values) have been suggested as valuable complementary paleoclimate proxies. In permafrost forests, tree growth is influenced by multiple factors, however temperature appears to have the strongest impact on tree growth and, therefore, on carbon cycling. To test whether δ2HLM and δ13CLM values of trees from permafrost regions might record climate parameters, two dominant tree species (Larix gmelinii, larch, and Pinus sylvestris var. mongolica, pine) collected from a permafrost forest in China's Greater Hinggan Mountains, were investigated. The two tree species larch and pine covered time spans of 1940 to 2013 and 1870 to 2013, respectively. Results showed significant correlations of pine and larch δ2HLM values and larch δ13CLM values with temperatures and in particular with the mean temperature of the growing season from April to August. However, only weak correlations of δ2HLM and δ13CLM values with moisture conditions, such as precipitation amount and relative humidity were observed. In addition, species specificity in the climate response was most obvious for δ13CLM values. Compared to a temperature reconstruction based on tree ring width, pine δ2HLM-based reconstruction showed strongest spatial correlations with regional temperature. Therefore, δ2HLM values might be a promising proxy to reconstruct growing-season temperatures in permafrost regions.
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Affiliation(s)
- Yabo Wang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Xiaohong Liu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China; State Key Laboratory of Cryospheric Sciences, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China.
| | - Tobias Anhäuser
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany; Department of Chemical and Physical Sciences, University of Toronto Mississauga, Mississauga L5L1C6, Canada
| | - Qiangqiang Lu
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China; Xi'an Botanical Garden of Shaanxi Province (Institute of Botany of Shaanxi Province), Xi'an 710061, China
| | - Xiaomin Zeng
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Qiuliang Zhang
- Forest College of Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China
| | - Keyi Wang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Lingnan Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Yu Zhang
- School of Geography and Tourism, Shaanxi Normal University, Xi'an 710119, China
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany; Heidelberg Center for the Environment HCE, Heidelberg University, D-69120 Heidelberg, Germany
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16
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Keppler F, Röhling AN, Jaeger N, Schroll M, Hartmann SC, Greule M. Sources and sinks of chloromethane in a salt marsh ecosystem: constraints from concentration and stable isotope measurements of laboratory incubation experiments. Environ Sci Process Impacts 2020; 22:627-641. [PMID: 32080692 DOI: 10.1039/c9em00540d] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Chloromethane (CH3Cl) is the most abundant long-lived chlorinated organic compound in the atmosphere and contributes significantly to natural stratospheric ozone depletion. Salt marsh ecosystems including halophyte plants are a known source of atmospheric CH3Cl but estimates of their total global source strength are highly uncertain and knowledge of the major production and consumption processes in the atmosphere-halophyte-soil system is yet incomplete. In this study we investigated the halophyte plant, Salicornia europaea, and soil samples from a coastal salt marsh site in Sardinia/Italy for their potential to emit and consume CH3Cl and using flux measurements, stable isotope techniques and Arrhenius plots differentiated between biotic and abiotic processes. Our laboratory approach clearly shows that at least 6 different production and consumption processes are active in controlling atmospheric CH3Cl fluxes of a salt marsh ecosystem. CH3Cl release by dried plant and soil material was substantially higher than that from the fresh material at temperatures ranging from 20 to 70 °C. Results of Arrhenius plots helped to distinguish between biotic and abiotic formation processes in plants and soils. Biotic CH3Cl consumption rates were highest at 30 °C for plants and 50 °C for soils, and microbial uptake was higher in soils with higher organic matter content. Stable isotope techniques helped to distinguish between formation and degradation processes and also provided a deeper insight into potential methyl moiety donor compounds, such as S-adenosyl-l-methionine, S-methylmethionine and pectin, that might be involved in the abiotic and biotic CH3Cl production processes. Our results clearly indicate that cycling of CH3Cl in salt marsh ecosystems is a result of several biotic and abiotic processes occurring simultaneously in the atmosphere-plant-soil system. Important precursor compounds for biotic and abiotic CH3Cl formation might be methionine derivatives and pectin. All formation and degradation processes are temperature dependent and thus environmental changes might affect the strength of each source and sink within salt marsh ecosystems and thus considerably alter total fluxes of CH3Cl from salt marsh ecosystems to the atmosphere.
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Affiliation(s)
- Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany.
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17
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Hartmann JF, Günthel M, Klintzsch T, Kirillin G, Grossart HP, Keppler F, Isenbeck-Schröter M. High Spatiotemporal Dynamics of Methane Production and Emission in Oxic Surface Water. Environ Sci Technol 2020; 54:1451-1463. [PMID: 31909604 DOI: 10.1021/acs.est.9b03182] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The discovery of methane (CH4) accumulation in oxic marine and limnic waters has redefined the role of aquatic environments in the regional CH4 cycle. Although CH4 accumulation in oxic surface waters became apparent in recent years, the sources are still subject to controversial discussions. We present high-resolution in situ measurements of CH4 concentration and its stable isotope composition in a stratified mesotrophic lake. We show that CH4 accumulation in surface waters originates from a highly dynamic interplay between (oxic) CH4 production and emission to the atmosphere. Laboratory incubations of different phytoplankton types and application of stable isotope techniques provide a first unambiguous evidence that major phytoplankton classes in Lake Stechlin per se produce CH4 under oxic conditions. Combined field and lab results show that the photoautotroph community is an important driver for CH4 production and its highly dynamic accumulation in oxic surface waters.
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Affiliation(s)
- Jan F Hartmann
- Institute of Earth Sciences , Heidelberg University , Im Neuenheimer Feld 236 , D-69120 Heidelberg , Germany
| | - Marco Günthel
- Department of Biosciences , Swansea University , Swansea SA2 8PP , U.K
| | - Thomas Klintzsch
- Institute of Earth Sciences , Heidelberg University , Im Neuenheimer Feld 236 , D-69120 Heidelberg , Germany
| | - Georgiy Kirillin
- Department of Ecohydrology , Leibniz-Institute of Freshwater Ecology and Inland Fisheries , Müggelseedamm 310 , D-12587 Berlin , Germany
| | - Hans-Peter Grossart
- Department of Experimental Limnology , Leibniz-Institute of Freshwater Ecology and Inland Fisheries , Alte Fischerhuette 2 , D-16775 Stechlin , Germany
- Institute of Biochemistry and Biology , Potsdam University , Maulbeerallee 2 , D-14469 Potsdam , Germany
| | - Frank Keppler
- Institute of Earth Sciences , Heidelberg University , Im Neuenheimer Feld 236 , D-69120 Heidelberg , Germany
- Heidelberg Center for the Environment (HCE) , Heidelberg University , D-69120 Heidelberg , Germany
| | - Margot Isenbeck-Schröter
- Institute of Earth Sciences , Heidelberg University , Im Neuenheimer Feld 236 , D-69120 Heidelberg , Germany
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18
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Keppler F, Barnes JD, Horst A, Bahlmann E, Luo J, Nadalig T, Greule M, Hartmann SC, Vuilleumier S. Chlorine Isotope Fractionation of the Major Chloromethane Degradation Processes in the Environment. Environ Sci Technol 2020; 54:1634-1645. [PMID: 31880153 DOI: 10.1021/acs.est.9b06139] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Chloromethane (CH3Cl) is an important source of chlorine in the stratosphere, but detailed knowledge of the magnitude of its sources and sinks is missing. Here, we measured the stable chlorine isotope fractionation (εCl) associated with the major abiotic and biotic CH3Cl sinks in the environment, namely, CH3Cl degradation by hydroxyl (·OH) and chlorine (·Cl) radicals in the troposphere and by reference bacteria Methylorubrum extorquens CM4 and Leisingera methylohalidivorans MB2 from terrestrial and marine environments, respectively. No chlorine isotope fractionation was detected for reaction of CH3Cl with ·OH and ·Cl radicals, whereas a large chlorine isotope fractionation (εCl) of -10.9 ± 0.7‰ (n = 3) and -9.4 ± 0.9 (n = 3) was found for CH3Cl degradation by M. extorquens CM4 and L. methylohalidivorans MB2, respectively. The large difference in chlorine isotope fractionation observed between tropospheric and bacterial degradation of CH3Cl provides an effective isotopic tool to characterize and distinguish between major abiotic and biotic processes contributing to the CH3Cl sink in the environment. Our findings demonstrate the potential of emerging triple-element isotopic approaches including chlorine to carbon and hydrogen analysis for the assessment of global cycling of organochlorines.
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Affiliation(s)
- Frank Keppler
- Institute of Earth Sciences , Heidelberg University , Im Neuenheimer Feld 236 , 69120 Heidelberg , Germany
| | - Jaime D Barnes
- Department of Geological Sciences , University of Texas , Austin , Texas 78712 , United States
| | - Axel Horst
- Department of Isotope Biogeochemistry , Helmholtz Centre for Environmental Research - UFZ , Permoserstr.15 , 04318 Leipzig , Germany
| | - Enno Bahlmann
- Leibniz Institute for Baltic Sea Research Warnemünde , Seestrasse 15 , 18119 Rostock , Germany
| | - Jing Luo
- UMR 7156 CNRS Génétique Moléculaire, Génomique, Microbiologie , Université de Strasbourg , 4 allée Konrad Roentgen , 67000 Strasbourg , France
| | - Thierry Nadalig
- UMR 7156 CNRS Génétique Moléculaire, Génomique, Microbiologie , Université de Strasbourg , 4 allée Konrad Roentgen , 67000 Strasbourg , France
| | - Markus Greule
- Institute of Earth Sciences , Heidelberg University , Im Neuenheimer Feld 236 , 69120 Heidelberg , Germany
| | - S Christoph Hartmann
- Institute of Earth Sciences , Heidelberg University , Im Neuenheimer Feld 236 , 69120 Heidelberg , Germany
- Max Planck Institute for Chemistry , Hahn-Meitner-Weg 1 , 55128 Mainz , Germany
| | - Stéphane Vuilleumier
- UMR 7156 CNRS Génétique Moléculaire, Génomique, Microbiologie , Université de Strasbourg , 4 allée Konrad Roentgen , 67000 Strasbourg , France
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19
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Bižić M, Klintzsch T, Ionescu D, Hindiyeh MY, Günthel M, Muro-Pastor AM, Eckert W, Urich T, Keppler F, Grossart HP. Aquatic and terrestrial cyanobacteria produce methane. Sci Adv 2020; 6:eaax5343. [PMID: 31998836 PMCID: PMC6962044 DOI: 10.1126/sciadv.aax5343] [Citation(s) in RCA: 94] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 11/19/2019] [Indexed: 05/08/2023]
Abstract
Evidence is accumulating to challenge the paradigm that biogenic methanogenesis, considered a strictly anaerobic process, is exclusive to archaea. We demonstrate that cyanobacteria living in marine, freshwater, and terrestrial environments produce methane at substantial rates under light, dark, oxic, and anoxic conditions, linking methane production with light-driven primary productivity in a globally relevant and ancient group of photoautotrophs. Methane production, attributed to cyanobacteria using stable isotope labeling techniques, was enhanced during oxygenic photosynthesis. We suggest that the formation of methane by cyanobacteria contributes to methane accumulation in oxygen-saturated marine and limnic surface waters. In these environments, frequent cyanobacterial blooms are predicted to further increase because of global warming potentially having a direct positive feedback on climate change. We conclude that this newly identified source contributes to the current natural methane budget and most likely has been producing methane since cyanobacteria first evolved on Earth.
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Affiliation(s)
- M. Bižić
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2, D-16775 Stechlin, Germany
- Corresponding author. (M.B.); (H.-P.G.)
| | - T. Klintzsch
- Institute of Earth Sciences, Biogeochemistry Group, Heidelberg University, Heidelberg, Germany
| | - D. Ionescu
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2, D-16775 Stechlin, Germany
| | - M. Y. Hindiyeh
- Department of Water and Environmental Engineering, German Jordanian University, Amman, Jordan
| | - M. Günthel
- Department of Biosciences, Swansea University, SA2 8PP Swansea, UK
- Medical University of Gdańsk, Department of International Research Agenda 3P–Medicine, Marii Skłodowskiej-Curie 3a, 80-210 Gdańsk, Poland
| | - A. M. Muro-Pastor
- Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, Sevilla, Spain
| | - W. Eckert
- Israel Oceanographic and Limnological Research, Yigal Allon Kinneret Limnological Laboratory, Migdal 14650, Israel
| | - T. Urich
- Institute of Microbiology, Center for Functional Genomics, University of Greifswald, Felix-Hausdorff-Str. 8, 17489 Greifswald, Germany
| | - F. Keppler
- Institute of Earth Sciences, Biogeochemistry Group, Heidelberg University, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg University, 69120 Heidelberg, Germany
| | - H.-P. Grossart
- Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhuette 2, D-16775 Stechlin, Germany
- Institute of Biochemistry and Biology, Potsdam University, Maulbeerallee 2, 14469 Potsdam, Germany
- Corresponding author. (M.B.); (H.-P.G.)
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20
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Abstract
Biological methane formation is associated with anoxic environments and the activity of anaerobic prokaryotes (Archaea). However, recent studies have confirmed methane release from eukaryotes, including plants, fungi, and animals, even in the absence of microbes and in the presence of oxygen. Furthermore, it was found that aerobic methane emission in plants is stimulated by a variety of environmental stress factors, leading to reactive oxygen species (ROS) generation. Further research presented evidence that molecules with sulfur and nitrogen bonded methyl groups such as methionine or choline are carbon precursors of aerobic methane formation. Once generated, methane is widely considered to be physiologically inert in eukaryotes, but several studies have found association between mammalian methanogenesis and gastrointestinal (GI) motility changes. In addition, a number of recent reports demonstrated anti-inflammatory potential for exogenous methane-based approaches in model anoxia-reoxygenation experiments. It has also been convincingly demonstrated that methane can influence the downstream effectors of transiently increased ROS levels, including mitochondria-related pro-apoptotic pathways during ischemia-reperfusion (IR) conditions. Besides, exogenous methane can modify the outcome of gasotransmitter-mediated events in plants, and it appears that similar mechanism might be active in mammals as well. This review summarizes the relevant literature on methane-producing processes in eukaryotes, and the available results that underscore its bioactivity. The current evidences suggest that methane liberation and biological effectiveness are both linked to cellular redox regulation. The data collectively imply that exogenous methane influences the regulatory mechanisms and signaling pathways involved in oxidative and nitrosative stress responses, which suggests a modulator role for methane in hypoxia-linked pathologies.
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Affiliation(s)
- Mihály Boros
- Institute of Surgical Research, Interdisciplinary Centre of Excellence, University of Szeged, Szeged, Hungary
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany
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21
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Bringel F, Besaury L, Amato P, Kröber E, Kolb S, Keppler F, Vuilleumier S, Nadalig T. Methylotrophs and Methylotroph Populations for Chloromethane Degradation. Curr Issues Mol Biol 2019; 33:149-172. [PMID: 31166190 DOI: 10.21775/cimb.033.149] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
Chloromethane is a halogenated volatile organic compound, produced in large quantities by terrestrial vegetation. After its release to the troposphere and transport to the stratosphere, its photolysis contributes to the degradation of stratospheric ozone. A better knowledge of chloromethane sources (production) and sinks (degradation) is a prerequisite to estimate its atmospheric budget in the context of global warming. The degradation of chloromethane by methylotrophic communities in terrestrial environments is a major underestimated chloromethane sink. Methylotrophs isolated from soils, marine environments and more recently from the phyllosphere have been grown under laboratory conditions using chloromethane as the sole carbon source. In addition to anaerobes that degrade chloromethane, the majority of cultivated strains were isolated in aerobiosis for their ability to use chloromethane as sole carbon and energy source. Among those, the Proteobacterium Methylobacterium (recently reclassified as Methylorubrum) harbours the only characterisized 'chloromethane utilization' (cmu) pathway, so far. This pathway is not representative of chloromethane-utilizing populations in the environment as cmu genes are rare in metagenomes. Recently, combined 'omics' biological approaches with chloromethane carbon and hydrogen stable isotope fractionation measurements in microcosms, indicated that microorganisms in soils and the phyllosphere (plant aerial parts) represent major sinks of chloromethane in contrast to more recently recognized microbe-inhabited environments, such as clouds. Cultivated chloromethane-degraders lacking the cmu genes display a singular isotope fractionation signature of chloromethane. Moreover, 13CH3Cl labelling of active methylotrophic communities by stable isotope probing in soils identify taxa that differ from the taxa known for chloromethane degradation. These observations suggest that new biomarkers for detecting active microbial chloromethane-utilizers in the environment are needed to assess the contribution of microorganisms to the global chloromethane cycle.
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Affiliation(s)
- Françoise Bringel
- Université de Strasbourg UMR 7156 UNISTRA CNRS, Laboratory of Molecular Genetics, Genomics, Microbiology (GMGM), Strasbourg, France
| | - Ludovic Besaury
- Université de Reims Champagne-Ardenne, Chaire AFERE, INRA, FARE UMR A614, Reims, France
| | - Pierre Amato
- Institut de Chimie de Clermont-Ferrand (ICCF), UMR6296 CNRS-UCA-Sigma, Clermont-Ferrand, France
| | - Eileen Kröber
- Institute of Landscape Biogeochemistry - Leibniz Centre for Agricultural Landscape Research - ZALF, Müncheberg, Germany
| | - Steffen Kolb
- Institute of Landscape Biogeochemistry - Leibniz Centre for Agricultural Landscape Research - ZALF, Müncheberg, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Heidelberg, Germany, and Heidelberg Center for the Environment HCE, Heidelberg University, Heidelberg, Germany
| | - Stéphane Vuilleumier
- Université de Strasbourg UMR 7156 UNISTRA CNRS, Laboratory of Molecular Genetics, Genomics, Microbiology (GMGM), Strasbourg, France
| | - Thierry Nadalig
- Université de Strasbourg UMR 7156 UNISTRA CNRS, Laboratory of Molecular Genetics, Genomics, Microbiology (GMGM), Strasbourg, France
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22
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Greule M, Moossen H, Geilmann H, Brand WA, Keppler F. Methyl sulfates as methoxy isotopic reference materials for δ 13 C and δ 2 H measurements. Rapid Commun Mass Spectrom 2019; 33:343-350. [PMID: 30452095 DOI: 10.1002/rcm.8355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 11/09/2018] [Accepted: 11/09/2018] [Indexed: 06/09/2023]
Abstract
RATIONALE Stable hydrogen and carbon isotope ratios of methoxy groups (OCH3 ) of plant organic matter have many potential applications in biogeochemical, atmospheric and food research. So far, most of the analyses of plant methoxy groups by isotope ratio mass spectrometry have employed liquid iodomethane (CH3 I) as the reference material to normalise stable isotope measurements of these moieties to isotope-δ scales. However, comparisons of measurements of stable hydrogen and carbon isotopes of plant methoxy groups are still hindered by the lack of suitable reference materials. METHODS We have investigated two methyl sulfate salts (HUBG1 and HUBG2), which exclusively contain carbon and hydrogen from one methoxy group, for their suitability as methoxy reference materials. Firstly, the stable hydrogen and carbon isotope values of the bulk compounds were calibrated against international reference substances by high-temperature conversion- and elemental analyser isotope ratio mass spectrometry (HTC- and EA-IRMS). In a second step these values were compared with values obtained by measurements using gas chromatography/isotope ratio mass spectrometry (GC/IRMS) where prior to analysis the methoxy groups were converted into gaseous iodomethane. RESULTS The 2 H- and 13 C isotopic abundances of HUBG1 measured by HTC- and EA-IRMS and expressed as δ-values on the usual international scales are -144.5 ± 1.2 mUr (n = 30) and -50.31 ± 0.16 mUr (n = 14), respectively. For HUBG2 we obtained -102.0 ± 1.3 mUr (n = 32) and +1.60 ± 0.12 mUr (n = 16). Furthermore, the values obtained by GC/IRMS were in good agreement with the HTC- and EA-IRMS values. CONCLUSIONS We suggest that both methyl sulfates are suitable reference materials for normalisation of isotope measurements of carbon of plant methoxy groups to isotope-δ scales and for inter-laboratory calibration. For stable hydrogen isotope measurements, we suggest that in addition to HUBG1 and HUBG2 additional reference materials are required to cover the full range of plant methoxy groups reported so far.
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Affiliation(s)
- Markus Greule
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120, Heidelberg, Germany
| | - Heiko Moossen
- Max-Planck-Institute for Biogeochemistry, Hans-Knoell-Str. 10, 07749, Jena, Germany
| | - Heike Geilmann
- Max-Planck-Institute for Biogeochemistry, Hans-Knoell-Str. 10, 07749, Jena, Germany
| | - Willi A Brand
- Max-Planck-Institute for Biogeochemistry, Hans-Knoell-Str. 10, 07749, Jena, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg University, 69120, Heidelberg, Germany
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Lenhart K, Behrendt T, Greiner S, Steinkamp J, Well R, Giesemann A, Keppler F. Nitrous oxide effluxes from plants as a potentially important source to the atmosphere. New Phytol 2019; 221:1398-1408. [PMID: 30303249 DOI: 10.1111/nph.15455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Accepted: 08/19/2018] [Indexed: 05/12/2023]
Abstract
The global budget for nitrous oxide (N2 O), an important greenhouse gas and probably dominant ozone-depleting substance emitted in the 21st century, is far from being fully understood. Cycling of N2 O in terrestrial ecosystems has traditionally exclusively focused on gas exchange between the soil surface (nitrification-denitrification processes) and the atmosphere. Terrestrial vegetation has not been considered in the global budget so far, even though plants are known to release N2 O. Here, we report the N2 O emission rates of 32 plant species from 22 different families measured under controlled laboratory conditions. Furthermore, the first isotopocule values (δ15 N, δ18 O and δ15 Nsp ) of N2 O emitted from plants were determined. A robust relationship established between N2 O emission and CO2 respiration rates, which did not alter significantly over a broad range of changing environmental conditions, was used to quantify plant-derived emissions on an ecosystem scale. Stable isotope measurements (δ15 N, δ18 O and δ15 Nsp ) of N2 O emitted by plants clearly show that the dual isotopocule fingerprint of plant-derived N2 O differs from that of currently known microbial or chemical processes. Our work suggests that vegetation is a natural source of N2 O in the environment with a large fraction released by a hitherto unrecognized process.
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Affiliation(s)
- Katharina Lenhart
- Bingen University of Applied Sciences, Berlinstr. 109, Bingen, 55411, Germany
- Center for Organismal Studies, Im Neuenheimer Feld 360, Heidelberg, 69120, Germany
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, Heidelberg, D-69120, Germany
| | - Thomas Behrendt
- Max-Planck-Institute for Biogeochemistry, Hans Knöll Str. 10, Jena, 07745, Germany
| | - Steffen Greiner
- Center for Organismal Studies, Im Neuenheimer Feld 360, Heidelberg, 69120, Germany
| | - Jörg Steinkamp
- Biodiversity and Climate Research Centre, Senckenberg Gesellschaft für Naturforschung, Senckenberganlage 25, Frankfurt am Main, 60325, Germany
- Johannes Gutenberg-Universität, Anselm-Franz-von-Bentzel-Weg 12, D-55128 Mainz, Germany
| | - Reinhard Well
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, Braunschweig, D-38116, Germany
| | - Anette Giesemann
- Thünen-Institute of Climate-Smart Agriculture, Bundesallee 50, Braunschweig, D-38116, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, Heidelberg, D-69120, Germany
- Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, D-69120, Germany
- Max-Planck-Institute for Chemistry, Hahn-Meitner-Weg 1, Mainz, D-55128, Germany
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Affiliation(s)
- Peter Comba
- Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
| | - Dieter Faltermeier
- Anorganisch-Chemisches Institut and Interdisciplinary Center for Scientific Computing (IWR), Heidelberg University, Heidelberg, Germany
| | - Sascha Gieger
- Institute of Earth Sciences and Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany
| | - Frank Keppler
- Institute of Earth Sciences and Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany
| | - Heinz Friedrich Schöler
- Institute of Earth Sciences and Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany
| | - Moritz Schroll
- Institute of Earth Sciences and Heidelberg Center for the Environment (HCE), Heidelberg University, Heidelberg, Germany
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Jaeger N, Besaury L, Röhling AN, Koch F, Delort AM, Gasc C, Greule M, Kolb S, Nadalig T, Peyret P, Vuilleumier S, Amato P, Bringel F, Keppler F. Chloromethane formation and degradation in the fern phyllosphere. Sci Total Environ 2018; 634:1278-1287. [PMID: 29660879 DOI: 10.1016/j.scitotenv.2018.03.316] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 03/25/2018] [Accepted: 03/25/2018] [Indexed: 06/08/2023]
Abstract
Chloromethane (CH3Cl) is the most abundant halogenated trace gas in the atmosphere. It plays an important role in natural stratospheric ozone destruction. Current estimates of the global CH3Cl budget are approximate. The strength of the CH3Cl global sink by microbial degradation in soils and plants is under discussion. Some plants, particularly ferns, have been identified as substantial emitters of CH3Cl. Their ability to degrade CH3Cl remains uncertain. In this study, we investigated the potential of leaves from 3 abundant ferns (Osmunda regalis, Cyathea cooperi, Dryopteris filix-mas) to produce and degrade CH3Cl by measuring their production and consumption rates and their stable carbon and hydrogen isotope signatures. Investigated ferns are able to degrade CH3Cl at rates from 2.1 to 17 and 0.3 to 0.9μggdw-1day-1 for C. cooperi and D. filix-mas respectively, depending on CH3Cl supplementation and temperature. The stable carbon isotope enrichment factor of remaining CH3Cl was -39±13‰, whereas negligible isotope fractionation was observed for hydrogen (-8±19‰). In contrast, O. regalis did not consume CH3Cl, but produced it at rates ranging from 0.6 to 128μggdw-1day-1, with stable isotope values of -97±8‰ for carbon and -202±10‰ for hydrogen, respectively. Even though the 3 ferns showed clearly different formation and consumption patterns, their leaf-associated bacterial diversity was not notably different. Moreover, we did not detect genes associated with the only known chloromethane utilization pathway "cmu" in the microbial phyllosphere of the investigated ferns. Our study suggests that still unknown CH3Cl biodegradation processes on plants play an important role in global cycling of atmospheric CH3Cl.
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Affiliation(s)
- Nicole Jaeger
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany.
| | - Ludovic Besaury
- Institut de Chimie de Clermont-Ferrand (ICCF), UMR6096 CNRS-UCA-Sigma, Clermont-Ferrand, France; Université de Strasbourg, CNRS, GMGM UMR 7156, Department of Microbiology, Genomics and the Environment, Strasbourg, France; UMR FARE, Université de Reims Champagne Ardenne, INRA, Reims, France
| | - Amelie Ninja Röhling
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany
| | - Fabien Koch
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany
| | - Anne-Marie Delort
- Institut de Chimie de Clermont-Ferrand (ICCF), UMR6096 CNRS-UCA-Sigma, Clermont-Ferrand, France
| | - Cyrielle Gasc
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France
| | - Markus Greule
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany
| | - Steffen Kolb
- Microbial Biogeochemistry, Research Area Landscape Functioning, Leibniz Centre for Agricultural Landscape Research (ZALF), Müncheberg, Germany
| | - Thierry Nadalig
- Université de Strasbourg, CNRS, GMGM UMR 7156, Department of Microbiology, Genomics and the Environment, Strasbourg, France
| | - Pierre Peyret
- Université Clermont Auvergne, INRA, MEDIS, Clermont-Ferrand, France
| | - Stéphane Vuilleumier
- Université de Strasbourg, CNRS, GMGM UMR 7156, Department of Microbiology, Genomics and the Environment, Strasbourg, France
| | - Pierre Amato
- Institut de Chimie de Clermont-Ferrand (ICCF), UMR6096 CNRS-UCA-Sigma, Clermont-Ferrand, France
| | - Françoise Bringel
- Université de Strasbourg, CNRS, GMGM UMR 7156, Department of Microbiology, Genomics and the Environment, Strasbourg, France
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, Heidelberg, Germany; Heidelberg Center for the Environment HCE, Heidelberg University, Heidelberg, Germany.
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Abstract
In recent years, methane as a component of exhaled human breath has been considered as a potential bioindicator providing information on microbial activity in the intestinal tract. Several studies indicated a relationship between breath methane status and specific gastrointestinal disease. So far, almost no attention has been given to the temporal variability of breath methane production by individual persons. Thus here, for the first time, long-term monitoring was carried out measuring breath methane of three volunteers over periods between 196 and 1002days. Results were evaluated taking into consideration the health status and specific medical intervention events for each individual during the monitoring period, and included a gastroscopy procedure, a vaccination, a dietary change, and chelate therapy. As a major outcome, breath methane mixing ratios show considerable variability within a person-specific range of values. Interestingly, decreased breath methane production often coincided with gastrointestinal complaints whereas influenza infections were mostly accompanied by increased breath methane production. A gastroscopic examination as well as a change to a low-fructose diet led to a dramatic shift of methane mixing ratios from high to low methane production. In contrast, a typhus vaccination as well as single chelate injections resulted in significant short-term methane peaks. Thus, this study clearly shows that humans can change from high to low methane emitters and vice versa within relatively short time periods. In the case of low to medium methane emitters the increase observed in methane mixing ratios, likely resulting from immune reactions and inflammatory processes, might indicate non-microbial methane formation under aerobic conditions. Although detailed reaction pathways are not yet known, aerobic methane formation might be related to cellular oxidative-reductive stress reactions. However, a detailed understanding of the pathways involved in human methane formation is necessary to enable comprehensive interpretation of methane breath levels.
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Affiliation(s)
- Daniela Polag
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany.
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany
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May T, Polag D, Keppler F, Greule M, Müller L, König H. Methane oxidation in industrial biogas plants—Insights in a novel methanotrophic environment evidenced by pmoA gene analyses and stable isotope labelling studies. J Biotechnol 2018; 270:77-84. [DOI: 10.1016/j.jbiotec.2018.01.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2017] [Revised: 01/24/2018] [Accepted: 01/31/2018] [Indexed: 02/05/2023]
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Jaeger N, Besaury L, Kröber E, Delort AM, Greule M, Lenhart K, Nadalig T, Vuilleumier S, Amato P, Kolb S, Bringel F, Keppler F. Chloromethane Degradation in Soils: A Combined Microbial and Two-Dimensional Stable Isotope Approach. J Environ Qual 2018; 47:254-262. [PMID: 29634809 DOI: 10.2134/jeq2017.09.0358] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Chloromethane (CHCl, methyl chloride) is the most abundant volatile halocarbon in the atmosphere and involved in stratospheric ozone depletion. The global CHCl budget, and especially the CHCl sink from microbial degradation in soil, still involves large uncertainties. These may potentially be resolved by a combination of stable isotope analysis and bacterial diversity studies. We determined the stable isotope fractionation of CHCl hydrogen and carbon and investigated bacterial diversity during CHCl degradation in three soils with different properties (forest, grassland, and agricultural soils) and at different temperatures and headspace mixing ratios of CHCl. The extent of chloromethane degradation decreased in the order forest > grassland > agricultural soil. Rates ranged from 0.7 to 2.5 μg g dry wt. d for forest soil, from 0.1 to 0.9 μg g dry wt. d for grassland soil, and from 0.1 to 0.4 μg g dry wt. d for agricultural soil and increased with increasing temperature and CHCl supplementation. The measured mean stable hydrogen enrichment factor of CHCl of -50 ± 13‰ was unaffected by temperature, mixing ratio, or soil type. In contrast, the stable carbon enrichment factor depended on CHCl degradation rates and ranged from -38 to -11‰. Bacterial community composition correlated with soil properties was independent from CHCl degradation or isotope enrichment. Nevertheless, increased abundance after CHCl incubation was observed in 21 bacterial operational taxonomical units (OTUs at the 97% 16S RNA sequence identity level). This suggests that some of these bacterial taxa, although not previously associated with CHCl degradation, may play a role in the microbial CHCl sink in soil.
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Keppler F, Fischer J, Sattler T, Polag D, Jaeger N, Schöler HF, Greule M. Chloromethane emissions in human breath. Sci Total Environ 2017; 605-606:405-410. [PMID: 28672229 DOI: 10.1016/j.scitotenv.2017.06.202] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 06/23/2017] [Accepted: 06/24/2017] [Indexed: 06/07/2023]
Abstract
Chloromethane (CH3Cl), currently the most abundant chlorinated organic compound in the atmosphere at around ~550 parts per trillion by volume (pptv), is considered responsible for approximately 16% of halogen-catalyzed stratospheric ozone destruction. Although emissions of CH3Cl are known to occur from animals such as cattle, formation and release of CH3Cl from humans has not yet been reported. In this study a pre-concentration unit coupled with a gas chromatograph directly linked to a mass spectrometer was used to precisely measure concentrations of CH3Cl at the pptv level in exhaled breath from 31 human subjects with ages ranging from 3 to 87years. We provide analytical evidence that all subjects exhaled CH3Cl in the range of 2.5 to 33 parts per billion by volume, levels which significantly exceed those of inhaled air by a factor of up to 60. If the mean of these emissions was typical for the world's population, then the global source of atmospheric CH3Cl from humans would be around 0.66Ggyr-1 (0.33 to 1.48Ggyr-1), which is less than 0.03% of the total annual global atmospheric source strength. The observed endogenous formation of a chlorinated methyl group in humans might be of interest to biochemists and medical scientists as CH3Cl is also known to be a potent methylating agent and thus, could be an important target compound in future medical research diagnostic programs.
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Affiliation(s)
- Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany; Heidelberg Center for the Environment (HCE), Heidelberg University, D-69120 Heidelberg, Germany.
| | - Jan Fischer
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Tobias Sattler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Daniela Polag
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Nicole Jaeger
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Heinz Friedrich Schöler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Markus Greule
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
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Riechelmann DFC, Greule M, Siegwolf RTW, Anhäuser T, Esper J, Keppler F. Warm season precipitation signal in δ 2 H values of wood lignin methoxyl groups from high elevation larch trees in Switzerland. Rapid Commun Mass Spectrom 2017; 31:1589-1598. [PMID: 28696517 DOI: 10.1002/rcm.7938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 06/01/2017] [Accepted: 07/09/2017] [Indexed: 06/07/2023]
Abstract
RATIONALE In this study, we tested stable hydrogen isotope ratios of wood lignin methoxyl groups (δ2 Hmethoxyl values) as a palaeoclimate proxy in dendrochronology. This is a quite new method in the field of dendrochronology and the sample preparation is much simpler than the methods used before to measure δ2 H values from wood. METHODS We measured δ2 Hmethoxyl values in high elevation larch trees (Larix decidua Mill.) from Simplon Valley (southern Switzerland). Thirty-seven larch trees were sampled and five individuals analysed for their δ2 Hmethoxyl values at annual (1971-2009) and pentadal resolution (1746-2009). The δ2 Hmethoxyl values were measured as CH3 I released upon treatment of the dried wood samples with hydroiodic acid. 10-90 μL from the head-space were injected into the gas chromatography/high-temperature conversion/isotope ratio mass spectrometry (GC/HTC-IRMS) system. RESULTS Testing the climate response of the δ2 Hmethoxyl values, the annually resolved series show a positive correlation of r = 0.60 with June/July precipitation. The pentadally resolved δ2 Hmethoxyl series do not show any significant correlation to climate parameters. CONCLUSIONS Increased precipitation during June and July, which are on average warm and relatively dry months, results in higher δ2 H values of the xylem water and, therefore, higher δ2 H values in the lignin methoxyl groups. Therefore, we suggest that δ2 Hmethoxyl values of high elevation larch trees might serve as a summer precipitation proxy.
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Affiliation(s)
- Dana F C Riechelmann
- Institute of Geography, Johannes Gutenberg-University Mainz, Johann-Joachim-Becher-Weg 21, 55128, Mainz, Germany
- Institute of Geosciences, Johannes Gutenberg-University Mainz, Johann-Joachim-Becher-Weg 21, 55128, Mainz, Germany
| | - Markus Greule
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, 69120, Heidelberg, Germany
- Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany
| | | | - Tobias Anhäuser
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, 69120, Heidelberg, Germany
| | - Jan Esper
- Institute of Geography, Johannes Gutenberg-University Mainz, Johann-Joachim-Becher-Weg 21, 55128, Mainz, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 236, 69120, Heidelberg, Germany
- Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128, Mainz, Germany
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Mulat DG, Mosbæk F, Ward AJ, Polag D, Greule M, Keppler F, Nielsen JL, Feilberg A. Exogenous addition of H 2 for an in situ biogas upgrading through biological reduction of carbon dioxide into methane. Waste Manag 2017. [PMID: 28623019 DOI: 10.1016/j.wasman.2017.05.054] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Biological reduction of CO2 into CH4 by exogenous addition of H2 is a promising technology for upgrading biogas into higher CH4 content. The aim of this work was to study the feasibility of exogenous H2 addition for an in situ biogas upgrading through biological conversion of the biogas CO2 into CH4. Moreover, this study employed systematic study with isotope analysis for providing comprehensive evidence on the underlying pathways of CH4 production and upstream processes. Batch reactors were inoculated with digestate originating from a full-scale biogas plant and fed once with maize leaf substrate. Periodic addition of H2 into the headspace resulted in a completely consumption of CO2 and a concomitant increase in CH4 content up to 89%. The microbial community and isotope analysis shows an enrichment of hydrogenotrophic Methanobacterium and the key role of hydrogenotrophic methanogenesis for biogas upgrading to higher CH4 content. Excess H2 was also supplied to evaluate its effect on overall process performance. The results show that excess H2 addition resulted in accumulation of H2, depletion of CO2 and inhibition of the degradation of acetate and other volatile fatty acids (VFA). A systematic isotope analysis revealed that excess H2 supply led to an increase in dissolved H2 to the level that thermodynamically inhibit the degradation of VFA and stimulate homo-acetogens for production of acetate from CO2 and H2. The inhibition was a temporary effect and acetate degradation resumed when the excess H2 was removed as well as in the presence of stoichiometric amount of H2 and CO2. This inhibition mechanism underlines the importance of carefully regulating the H2 addition rate and gas retention time to the CO2 production rate, H2-uptake rate and growth of hydrogenotrophic methanogens in order to achieve higher CH4 content without the accumulation of acetate and other VFA.
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Affiliation(s)
- Daniel Girma Mulat
- Department of Engineering, Aarhus University, Hangøvej 2, 8200 Aarhus N, Denmark
| | - Freya Mosbæk
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg E, Denmark
| | - Alastair James Ward
- Department of Engineering, Aarhus University, Hangøvej 2, 8200 Aarhus N, Denmark
| | - Daniela Polag
- Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Markus Greule
- Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Frank Keppler
- Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany
| | - Jeppe Lund Nielsen
- Department of Chemistry and Bioscience, Aalborg University, Fredrik Bajers Vej 7H, 9220 Aalborg E, Denmark
| | - Anders Feilberg
- Department of Engineering, Aarhus University, Hangøvej 2, 8200 Aarhus N, Denmark.
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Benzing K, Comba P, Martin B, Pokrandt B, Keppler F. Nonheme Iron‐Oxo‐Catalyzed Methane Formation from Methyl Thioethers: Scope, Mechanism, and Relevance for Natural Systems. Chemistry 2017; 23:10465-10472. [DOI: 10.1002/chem.201701986] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Kathrin Benzing
- Institute of Inorganic ChemistryHeidelberg University Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Peter Comba
- Institute of Inorganic Chemistry and Interdisciplinary Center for Scientific Computing (IWR)Heidelberg University Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Bodo Martin
- Institute of Inorganic ChemistryHeidelberg University Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Bianca Pokrandt
- Institute of Inorganic ChemistryHeidelberg University Im Neuenheimer Feld 270 69120 Heidelberg Germany
| | - Frank Keppler
- Institute of Earth Sciences and Heidelberg Center for the Environment (HCE)Heidelberg University Im Neuenheimer Feld 236 69120 Heidelberg Germany
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Schreiber U, Mayer C, Schmitz OJ, Rosendahl P, Bronja A, Greule M, Keppler F, Mulder I, Sattler T, Schöler HF. Organic compounds in fluid inclusions of Archean quartz-Analogues of prebiotic chemistry on early Earth. PLoS One 2017; 12:e0177570. [PMID: 28614348 PMCID: PMC5470662 DOI: 10.1371/journal.pone.0177570] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 04/27/2017] [Indexed: 01/03/2023] Open
Abstract
The origin of life is still an unsolved mystery in science. Hypothetically, prebiotic chemistry and the formation of protocells may have evolved in the hydrothermal environment of tectonic fault zones in the upper continental crust, an environment where sensitive molecules are protected against degradation induced e.g. by UV radiation. The composition of fluid inclusions in minerals such as quartz crystals which have grown in this environment during the Archean period might provide important information about the first organic molecules formed by hydrothermal synthesis. Here we present evidence for organic compounds which were preserved in fluid inclusions of Archean quartz minerals from Western Australia. We found a variety of organic compounds such as alkanes, halocarbons, alcohols and aldehydes which unambiguously show that simple and even more complex prebiotic organic molecules have been formed by hydrothermal processes. Stable-isotope analysis confirms that the methane found in the inclusions has most likely been formed from abiotic sources by hydrothermal chemistry. Obviously, the liquid phase in the continental Archean crust provided an interesting choice of functional organic molecules. We conclude that organic substances such as these could have made an important contribution to prebiotic chemistry which might eventually have led to the formation of living cells.
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Affiliation(s)
- Ulrich Schreiber
- Department of Geology, University Duisburg-Essen, Universitaetsstr. 5, Essen, Germany
| | - Christian Mayer
- Faculty of Chemistry, CeNIDE, University Duisburg-Essen, Universitaetsstr. 5, Essen, Germany
| | - Oliver J. Schmitz
- Faculty of Chemistry, Applied Analytical Chemistry, University Duisburg-Essen, Universitaetsstr. 5, Essen, Germany
| | - Pia Rosendahl
- Faculty of Chemistry, Applied Analytical Chemistry, University Duisburg-Essen, Universitaetsstr. 5, Essen, Germany
| | - Amela Bronja
- Faculty of Chemistry, Applied Analytical Chemistry, University Duisburg-Essen, Universitaetsstr. 5, Essen, Germany
| | - Markus Greule
- Institute of Earth Sciences, Ruprecht Karls University Heidelberg, Im Neuenheimer Feld 234–236, Heidelberg, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Ruprecht Karls University Heidelberg, Im Neuenheimer Feld 234–236, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Ruprecht Karls University Heidelberg, Heidelberg, Germany
| | - Ines Mulder
- Institute of Earth Sciences, Ruprecht Karls University Heidelberg, Im Neuenheimer Feld 234–236, Heidelberg, Germany
| | - Tobias Sattler
- Institute of Earth Sciences, Ruprecht Karls University Heidelberg, Im Neuenheimer Feld 234–236, Heidelberg, Germany
| | - Heinz F. Schöler
- Institute of Earth Sciences, Ruprecht Karls University Heidelberg, Im Neuenheimer Feld 234–236, Heidelberg, Germany
- Heidelberg Center for the Environment (HCE), Ruprecht Karls University Heidelberg, Heidelberg, Germany
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Geißler K, Greule M, Schäfer U, Hans J, Geißler T, Meier L, Keppler F, Krammer G. Vanilla authenticity control by DNA barcoding and isotope data aggregation. FLAVOUR FRAG J 2017. [DOI: 10.1002/ffj.3379] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Katrin Geißler
- Symrise AG; Mühlenfeldstrasse 1 37603 Holzminden Germany
| | - Markus Greule
- Heidelberg University; Institute of Earth Science; Im Neuenheimer Feld 234-236 69120 Heidelberg Germany
| | - Uwe Schäfer
- Symrise AG; Mühlenfeldstrasse 1 37603 Holzminden Germany
| | - Joachim Hans
- Symrise AG; Mühlenfeldstrasse 1 37603 Holzminden Germany
| | | | - Lars Meier
- Symrise AG; Mühlenfeldstrasse 1 37603 Holzminden Germany
| | - Frank Keppler
- Heidelberg University; Institute of Earth Science; Im Neuenheimer Feld 234-236 69120 Heidelberg Germany
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Anhäuser T, Greule M, Keppler F. Stable hydrogen isotope values of lignin methoxyl groups of four tree species across Germany and their implication for temperature reconstruction. Sci Total Environ 2017; 579:263-271. [PMID: 27889214 DOI: 10.1016/j.scitotenv.2016.11.109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2016] [Revised: 11/15/2016] [Accepted: 11/16/2016] [Indexed: 06/06/2023]
Abstract
Stable hydrogen isotope ratios of lignin methoxyl groups (δ2HLM values) in wood have been shown to mirror the δ2H signatures of precipitation (δ2Hprecip values). Thus, δ2HLM values were suggested to serve as a potential paleotemperature proxy since δ2Hprecip values are dominantly controlled by air temperature in the mid-latitudes. A recent study where a significant δ2HLM-temperature relationship was found for a European transect with mean annual temperatures ranging from -4 to 17°C strengthened this assumption. However, using δ2HLM values as a paleotemperature proxy requires quantification of noise from site-, species- and biosynthetic-specific influences to determine the significance of recording smaller temperature changes. Here, we measured δ2HLM values of tree-ring sections covering 1981-1990 and 1991-2011 of four different tree species (European beech, English oak, Scots pine, Norway spruce) at 15 sampling sites across Germany. The maximum difference in mean annual temperature between sample sites was 5°C and all sites showed small temperature increases from 1981 to 1990 to 1991-2011 (mean Δ=0.7°C). For all species investigated, the maximum difference of δ2HLM within the tree was <10mUr or ‰ (median values) and between trees at a single site was ≤28mUr (median values). The general pattern of the spatial δ2HLM-temperature relationship found for the European transect was confirmed here although a significant correlation was lacking. This can be explained by the lower spatial δ2Hprecip-temperature correlation (R2=0.39) found for sampling sites in this study and the δ2HLM differences between trees. Nevertheless, the temporal changes in δ2HLM values of European beech trees correctly reflected within ±2°C the temperature change at every sampling site. Therefore, we suggest that δ2HLM values of European beech trees have considerable potential for reconstructing temperature changes when applied on tree-ring chronologies and consider this approach particularly suited for Late Holocene climate studies.
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Affiliation(s)
- Tobias Anhäuser
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany.
| | - Markus Greule
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany; Heidelberg Center for the Environment (HCE), Heidelberg University, D-69120 Heidelberg, Germany
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Anhäuser T, Greule M, Polag D, Bowen GJ, Keppler F. Mean annual temperatures of mid-latitude regions derived from δ 2H values of wood lignin methoxyl groups and its implications for paleoclimate studies. Sci Total Environ 2017; 574:1276-1282. [PMID: 27712864 DOI: 10.1016/j.scitotenv.2016.07.189] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 07/08/2016] [Accepted: 07/26/2016] [Indexed: 06/06/2023]
Abstract
Tree-rings are widely used climate archives providing annual resolutions on centennial to millennial timescales. Stable isotope ratios of tree-rings have been applied to assist with the delineation of climate parameters such as temperature and precipitation. Here, we investigated stable hydrogen isotope ratios (expressed as δ2H values) of lignin methoxyl groups of wood from various tree species collected along a ~3500km north-south transect across Europe with mean annual temperatures (MAT) ranging from -4 to +17°C. We found a strong linear relationship between MATs and δ2H values of wood lignin methoxyl groups. We used this relationship to predict MATs from randomly collected wood samples and found general agreement between predicted and observed MATs for the mid-latitudes on a global scale. Our results are discussed in context of their paleoclimate relevance and suggest that δ2H values of lignin methoxyl groups might have the potential to reconstruct MATs when applied on mid-latitudinal tree-ring chronologies of the Late Holocene.
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Affiliation(s)
- Tobias Anhäuser
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany.
| | - Markus Greule
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany
| | - Daniela Polag
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany
| | - Gabriel J Bowen
- Department of Geology and Geophysics, Global Change and Sustainability Center, University of Utah, Salt Lake City, UT 84112, USA
| | - Frank Keppler
- Institute of Earth Sciences, Heidelberg University, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany; Heidelberg Center for the Environment (HCE), Heidelberg University, D-69120 Heidelberg, Germany; Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, D-55128 Mainz, Germany
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Keppler F, Schiller A, Ehehalt R, Greule M, Hartmann J, Polag D. Stable isotope and high precision concentration measurements confirm that all humans produce and exhale methane. J Breath Res 2016; 10:016003. [PMID: 26824393 DOI: 10.1088/1752-7155/10/1/016003] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Mammalian formation of methane (methanogenesis) is widely considered to occur exclusively by anaerobic microbial activity in the gastrointestinal tract. Approximately one third of humans, depending on colonization of the gut by methanogenic archaea, are considered methane producers based on the classification terminology of high and low emitters. In this study laser absorption spectroscopy was used to precisely measure concentrations and stable carbon isotope signatures of exhaled methane in breath samples from 112 volunteers with an age range from 1 to 80 years. Here we provide analytical evidence that volunteers exhaled methane levels were significantly above background (inhaled) air. Furthermore, stable carbon isotope values of the exhaled methane unambiguously confirmed that this gas was produced by all of the human subjects studied. Based on the emission and stable carbon isotope patterns of various age groups we hypothesize that next to microbial sources in the gastrointestinal tracts there might be other, as yet unidentified, processes involved in methane formation supporting the idea that humans might also produce methane endogenously in cells. Finally we suggest that stable isotope measurements of volatile organic compounds such as methane might become a useful tool in future medical research diagnostic programs.
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Affiliation(s)
- Frank Keppler
- Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234-236, 69120 Heidelberg, Germany. Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, 55128 Mainz, Germany. Heidelberg Center for the Environment (HCE), Ruprecht Karls University Heidelberg, D-69120 Heidelberg, Germany
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Polag D, May T, Müller L, König H, Jacobi F, Laukenmann S, Keppler F. Online monitoring of stable carbon isotopes of methane in anaerobic digestion as a new tool for early warning of process instability. Bioresour Technol 2015; 197:161-70. [PMID: 26335284 DOI: 10.1016/j.biortech.2015.08.058] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2015] [Revised: 08/08/2015] [Accepted: 08/12/2015] [Indexed: 05/16/2023]
Abstract
Effective control of anaerobic digestion in biogas plants requires the monitoring of process sensitive and rapid response parameters in order to ensure efficient biogas production and to prevent potential process failure. In this study, stable carbon isotopes of methane (δ(13)CCH4) produced in a full-scale continuous stirred-tank reactor were investigated as a potential new monitoring tool for this purpose. Over a six-month period with variable organic loading rates, δ(13)CCH4-values were measured online by a portable high-precision laser absorption spectrometer. During a stress period of consecutive high organic loading, δ(13)CCH4-values early indicated process changes in contrast to traditionally monitored parameters where a change was observed some five to ten days later. Comparison of the stable isotope values with data from microbial analyses showed a distinct relationship between the quantity of potentially acetoclastic methanogens and δ(13)CCH4-values. This finding indicates an association between dominant methanogenic pathways and carbon isotope values.
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Affiliation(s)
- D Polag
- Institute of Earth Sciences, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany
| | - T May
- Institute of Microbiology and Wine Research, Johann-Joachim-Becherweg 15, D-55128 Mainz, Germany
| | - L Müller
- Deutsches Biomasseforschungszentrum, Torgauer St. 116, D-04347 Leipzig, Germany
| | - H König
- Institute of Microbiology and Wine Research, Johann-Joachim-Becherweg 15, D-55128 Mainz, Germany
| | - F Jacobi
- Deutsches Biomasseforschungszentrum, Torgauer St. 116, D-04347 Leipzig, Germany
| | - S Laukenmann
- Institute of Earth Sciences, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany
| | - F Keppler
- Institute of Earth Sciences, Im Neuenheimer Feld 236, D-69120 Heidelberg, Germany
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Lenhart K, Weber B, Elbert W, Steinkamp J, Clough T, Crutzen P, Pöschl U, Keppler F. Nitrous oxide and methane emissions from cryptogamic covers. Glob Chang Biol 2015; 21:3889-900. [PMID: 26152454 DOI: 10.1111/gcb.12995] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2014] [Accepted: 05/10/2015] [Indexed: 05/13/2023]
Abstract
Cryptogamic covers, which comprise some of the oldest forms of terrestrial life on Earth (Lenton & Huntingford, ), have recently been found to fix large amounts of nitrogen and carbon dioxide from the atmosphere (Elbert et al., ). Here we show that they are also greenhouse gas sources with large nitrous oxide (N2 O) and small methane (CH4 ) emissions. Whilst N2 O emission rates varied with temperature, humidity, and N deposition, an almost constant ratio with respect to respiratory CO2 emissions was observed for numerous lichens and bryophytes. We employed this ratio together with respiration data to calculate global and regional N2 O emissions. If our laboratory measurements are typical for lichens and bryophytes living on ground and plant surfaces and scaled on a global basis, we estimate a N2 O source strength of 0.32-0.59 Tg year(-1) for the global N2 O emissions from cryptogamic covers. Thus, our emission estimate might account for 4-9% of the global N2 O budget from natural terrestrial sources. In a wide range of arid and forested regions, cryptogamic covers appear to be the dominant source of N2 O. We suggest that greenhouse gas emissions associated with this source might increase in the course of global change due to higher temperatures and enhanced nitrogen deposition.
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Affiliation(s)
- Katharina Lenhart
- Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, Mainz, 55128, Germany
- Department of Plant Ecology, Justus-Liebig-University, Heinrich-Buff-Ring 26-32, Gießen, 35392, Germany
- Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234-236, Heidelberg, 69120, Germany
| | - Bettina Weber
- Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, Mainz, 55128, Germany
| | - Wolfgang Elbert
- Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, Mainz, 55128, Germany
| | - Jörg Steinkamp
- Senckenberg Biodiversity and Climate Research Centre, Senckenberganlage 25, Frankfurt am Main, 60325, Germany
| | - Tim Clough
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, 7647, New Zealand
| | - Paul Crutzen
- Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, Mainz, 55128, Germany
| | - Ulrich Pöschl
- Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, Mainz, 55128, Germany
| | - Frank Keppler
- Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, Mainz, 55128, Germany
- Institute of Earth Sciences, University of Heidelberg, Im Neuenheimer Feld 234-236, Heidelberg, 69120, Germany
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Mischel M, Esper J, Keppler F, Greule M, Werner W. δ²H, δ¹³C and δ¹⁸O from whole wood, α-cellulose and lignin methoxyl groups in Pinus sylvestris: a multi-parameter approach. Isotopes Environ Health Stud 2015; 51:553-568. [PMID: 26156050 DOI: 10.1080/10256016.2015.1056181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Novel tree ring parameters - δ(13)C and δ(2)H from methoxyl groups - have been developed to reconstruct palaeoclimate. Tests with δ(13)C and δ(18)O derived from whole wood and cellulose samples, however, indicated differences in the isotopic composition and climate signal, depending on the extracted wood component. We assess this signal dependency by analysing (i) δ(13)C and δ(18)O from whole wood and cellulose and (ii) δ(13)C and δ(2)H from methoxyl groups, using Pinus sylvestris L. growing near Altenkirchen (Germany). Results indicate significant correlations among the time series derived from whole wood, cellulose, and lignin methoxyl groups. Compared with the whole wood samples, δ(13)C from methoxyl groups showed a different and overall lower response to climate parameters. On the other hand, δ(2)H from methoxyl groups showed high correlations with temperature and was also correlated with ring width, indicating its potential as a temperature proxy. Isotope time series with the highest correlation with climatic parameter were: (i) whole wood and cellulose δ(13)C with growing season precipitation and summer temperature; (ii) methoxyl groups with spring precipitation; (iii) whole wood and cellulose δ(18)O correlates with annual evapotranspiration and water balance; and (iv) methoxyl group δ(2)H with spring temperatures. These findings reveal that multiple climate elements can be reconstructed from different wood components and that whole wood proxies perform comparably to cellulose time series.
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Affiliation(s)
- Maria Mischel
- a Department of Geography , Johannes Gutenberg University , Mainz , Germany
- b Department of Geobotany , University of Trier , Trier , Germany
| | - Jan Esper
- a Department of Geography , Johannes Gutenberg University , Mainz , Germany
| | - Frank Keppler
- c Institute of Earth Sciences , University of Heidelberg , Heidelberg , Germany
| | - Markus Greule
- c Institute of Earth Sciences , University of Heidelberg , Heidelberg , Germany
| | - Willy Werner
- b Department of Geobotany , University of Trier , Trier , Germany
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Greule M, Mosandl A, Hamilton JTG, Keppler F. Comment on Authenticity and traceability of vanilla flavors by analysis of stable isotopes of carbon and hydrogen. J Agric Food Chem 2015; 63:5305-5306. [PMID: 25947204 DOI: 10.1021/jf506172q] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Affiliation(s)
- Markus Greule
- †Institute of Earth Sciences, Ruprecht Karls University Heidelberg, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany
- §Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, D-55128 Mainz, Germany
| | - Armin Mosandl
- §Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, D-55128 Mainz, Germany
| | - John T G Hamilton
- #School of Biological Sciences, Queen's University Belfast, 97 Lisburn Road, Belfast BT9 7BL, United Kingdom
| | - Frank Keppler
- †Institute of Earth Sciences, Ruprecht Karls University Heidelberg, Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany
- §Max Planck Institute for Chemistry, Hahn-Meitner-Weg 1, D-55128 Mainz, Germany
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Greule M, Rossmann A, Schmidt HL, Mosandl A, Keppler F. A stable isotope approach to assessing water loss in fruits and vegetables during storage. J Agric Food Chem 2015; 63:1974-1981. [PMID: 25674668 DOI: 10.1021/jf505192p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Plant tissue water is the source of oxygen and hydrogen in organic biomatter. Recently, we demonstrated that the stable hydrogen isotope value (δ(2)H) of plant methoxyl groups is a very reliable and easily available archive for the δ(2)H value of this tissue water. Here we show in a model experiment that the δ(2)H values of methoxyl groups remain unchanged after water loss during storage of fruits and vegetables under controlled conditions, while δ(2)H and δ(18)O values of tissue water increase. This enhancement is plant-dependent, and the correlation differs from the meteoric water line. The δ(18)O value is better correlated to the weight decrease of the samples. Therefore, we postulate that the δ(2)H value of methoxyl groups and the δ(18)O value of tissue water are suitable parameters for checking postharvest alterations of tissue water, either addition or loss.
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Affiliation(s)
- Markus Greule
- Institute of Earth Sciences, Ruprecht Karls University Heidelberg , Im Neuenheimer Feld 234-236, D-69120 Heidelberg, Germany
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Anhäuser T, Greule M, Zech M, Kalbitz K, McRoberts C, Keppler F. Stable hydrogen and carbon isotope ratios of methoxyl groups during plant litter degradation. Isotopes Environ Health Stud 2015; 51:143-154. [PMID: 25706484 DOI: 10.1080/10256016.2015.1013540] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Stable hydrogen and carbon isotope ratios of methoxyl groups (δ(2)Hmethoxyl and δ(13)Cmethoxyl values, respectively) in plant material have been shown to possess characteristic signatures. These isotopic signatures can be used for a variety of applications such as constraining the geographical origin and authenticity of biomaterials. Recently, it has also been suggested that δ(2)Hmethoxyl values of sedimentary organic matter of geological archives might serve as a palaeoclimate/-hydrology proxy. However, deposited organic matter is subject to both biotic and abiotic degradation processes, and therefore an evaluation of their potential impact on the δ(2)Hmethoxyl and δ(13)Cmethoxyl values would allow more reliable interpretations of both isotopic signatures. Here, we investigated this potential influence by exposing foliar litter of five different tree species (Sycamore maple, Mountain ash, European beech, Norway spruce and Scots pine) to natural degradation. The foliar litter was sampled at nine intervals over a 27-month period, and the bulk methoxyl content as well as the δ(2)Hmethoxyl and δ(13)Cmethoxyl values were measured. At the end of the experiment, a loss of the bulk methoxyl in the range of ∼40-70% was measured. Linear regression analysis showed no dependence of δ(2)Hmethoxyl values with methoxyl content for four out of five foliar litter samples studied (R(2) in the range of 0.03 and 0.36, p > .05). On the contrary, the δ(13)Cmethoxyl values showed significant linear correlations for the great majority of the foliar litter samples (R(2) in the range of 0.51 and 0.73, p < .05). The litter species with the greatest methoxyl loss (Mountain ash, Scots pine and Norway spruce) showed the strongest (13)C enrichment, by up to ∼5‰. Since δ(2)Hmethoxyl shows no systematic overall change during the course of degradation, we propose that there is considerable potential for its use as a palaeoclimate proxy for a wide range of geological archives containing, for instance, fossil wood or sedimentary organic matter. Care would need to be taken if δ(13)Cmethoxyl values of degraded organic matter are used for palaeoclimate/-environmental investigations.
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Affiliation(s)
- Tobias Anhäuser
- a Institute of Earth Sciences , University of Heidelberg , Heidelberg , Germany
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Nadalig T, Greule M, Bringel F, Keppler F, Vuilleumier S. Probing the diversity of chloromethane-degrading bacteria by comparative genomics and isotopic fractionation. Front Microbiol 2014; 5:523. [PMID: 25360131 PMCID: PMC4197683 DOI: 10.3389/fmicb.2014.00523] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 09/19/2014] [Indexed: 11/13/2022] Open
Abstract
Chloromethane (CH3Cl) is produced on earth by a variety of abiotic and biological processes. It is the most important halogenated trace gas in the atmosphere, where it contributes to ozone destruction. Current estimates of the global CH3Cl budget are uncertain and suggest that microorganisms might play a more important role in degrading atmospheric CH3Cl than previously thought. Its degradation by bacteria has been demonstrated in marine, terrestrial, and phyllospheric environments. Improving our knowledge of these degradation processes and their magnitude is thus highly relevant for a better understanding of the global budget of CH3Cl. The cmu pathway, for chloromethane utilisation, is the only microbial pathway for CH3Cl degradation elucidated so far, and was characterized in detail in aerobic methylotrophic Alphaproteobacteria. Here, we reveal the potential of using a two-pronged approach involving a combination of comparative genomics and isotopic fractionation during CH3Cl degradation to newly address the question of the diversity of chloromethane-degrading bacteria in the environment. Analysis of available bacterial genome sequences reveals that several bacteria not yet known to degrade CH3Cl contain part or all of the complement of cmu genes required for CH3Cl degradation. These organisms, unlike bacteria shown to grow with CH3Cl using the cmu pathway, are obligate anaerobes. On the other hand, analysis of the complete genome of the chloromethane-degrading bacterium Leisingera methylohalidivorans MB2 showed that this bacterium does not contain cmu genes. Isotope fractionation experiments with L. methylohalidivorans MB2 suggest that the unknown pathway used by this bacterium for growth with CH3Cl can be differentiated from the cmu pathway. This result opens the prospect that contributions from bacteria with the cmu and Leisingera-type pathways to the atmospheric CH3Cl budget may be teased apart in the future.
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Affiliation(s)
- Thierry Nadalig
- Université de Strasbourg, Equipe Adaptations et Interactions Microbiennes dans l'Environnement, Unitès Mixtes de Recherche 7156 Centre National de la Recherche Scientifique, Génétique Moléculaire, Génomique, Microbiologie Strasbourg, France
| | - Markus Greule
- Institute of Earth Sciences, Ruprecht Karls University Heidelberg Heidelberg, Germany
| | - Françoise Bringel
- Université de Strasbourg, Equipe Adaptations et Interactions Microbiennes dans l'Environnement, Unitès Mixtes de Recherche 7156 Centre National de la Recherche Scientifique, Génétique Moléculaire, Génomique, Microbiologie Strasbourg, France
| | - Frank Keppler
- Institute of Earth Sciences, Ruprecht Karls University Heidelberg Heidelberg, Germany
| | - Stéphane Vuilleumier
- Université de Strasbourg, Equipe Adaptations et Interactions Microbiennes dans l'Environnement, Unitès Mixtes de Recherche 7156 Centre National de la Recherche Scientifique, Génétique Moléculaire, Génomique, Microbiologie Strasbourg, France
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Polag D, Leiß O, Keppler F. Age dependent breath methane in the German population. Sci Total Environ 2014; 481:582-587. [PMID: 24631621 DOI: 10.1016/j.scitotenv.2014.02.086] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Revised: 02/17/2014] [Accepted: 02/17/2014] [Indexed: 06/03/2023]
Abstract
Methane which can sometimes be found in exhaled breath of humans is known to reflect in situ intestinal methanogenic activity. In recent years, several factors have been studied in order to understand their relevance to methane production in the intestinal tract. However, the relationship between age and methane producing status has hitherto not been sufficiently investigated. In the present study we evaluated the relationship between age and percentage of breath methane producers in the German population in 428 subjects with ages ranging from 4 to 95 years. When subjects were divided into age groups of 15 years, an increase in the percentage of breath methane producers with age was observed. The near linear increase (R(2)=0.977) from 5% for children (1-15 years) to 57% for the elderly (>75 years) may indicate a continuous development in the human gut methanogenic flora throughout lifetime. However, when subjects were compared on 5 year age intervals, an interruption in the percentage of methane producers in the sixth and seventh decade was noted. We further revealed an age dependence on the ratio of female to male producers. This is shown by a dominance in female breath methane producers during the first half of life which afterwards is replaced by a dominance in male breath methane producers with an approximately linear decrease in the ratio between 20 and 65 years (R(2)=0.926). These observations might suggest a relationship between methanogenic activity and hormonal factors. Using our data, we predict that the percentage of breath CH4 producers within the German population will increase from its current value of 30% (2013) to 35% by 2050.
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Affiliation(s)
- Daniela Polag
- Max-Planck-Institut für Chemie, Hahn-Meitner-Weg 1, D-55128 Mainz, Germany
| | - Ottmar Leiß
- Clinic of Gastroenterology, Wallstrasse 1-5, D-55128 Mainz, Germany
| | - Frank Keppler
- Max-Planck-Institut für Chemie, Hahn-Meitner-Weg 1, D-55128 Mainz, Germany
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Polag D, Krapf LC, Heuwinkel H, Laukenmann S, Lelieveld J, Keppler F. Stable carbon isotopes of methane for real-time process monitoring in anaerobic digesters. Eng Life Sci 2013. [DOI: 10.1002/elsc.201200201] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
| | - Lutz Christian Krapf
- Bavarian State Research Center for Agriculture; Institute for Agricultural Engineering and Animal Husbandry; Freising Germany
| | - Hauke Heuwinkel
- Bavarian State Research Center for Agriculture; Institute for Agricultural Engineering and Animal Husbandry; Freising Germany
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Nadalig T, Greule M, Bringel F, Vuilleumier S, Keppler F. Hydrogen and carbon isotope fractionation during degradation of chloromethane by methylotrophic bacteria. Microbiologyopen 2013; 2:893-900. [PMID: 24019296 PMCID: PMC3892336 DOI: 10.1002/mbo3.124] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Revised: 07/10/2013] [Accepted: 07/21/2013] [Indexed: 01/12/2023] Open
Abstract
Chloromethane (CH3 Cl) is a widely studied volatile halocarbon involved in the destruction of ozone in the stratosphere. Nevertheless, its global budget still remains debated. Stable isotope analysis is a powerful tool to constrain fluxes of chloromethane between various environmental compartments which involve a multiplicity of sources and sinks, and both biotic and abiotic processes. In this study, we measured hydrogen and carbon isotope fractionation of the remaining untransformed chloromethane following its degradation by methylotrophic bacterial strains Methylobacterium extorquens CM4 and Hyphomicrobium sp. MC1, which belong to different genera but both use the cmu pathway, the only pathway for bacterial degradation of chloromethane characterized so far. Hydrogen isotope fractionation for degradation of chloromethane was determined for the first time, and yielded enrichment factors (ε) of -29‰ and -27‰ for strains CM4 and MC1, respectively. In agreement with previous studies, enrichment in (13) C of untransformed CH3 Cl was also observed, and similar isotope enrichment factors (ε) of -41‰ and -38‰ were obtained for degradation of chloromethane by strains CM4 and MC1, respectively. These combined hydrogen and carbon isotopic data for bacterial degradation of chloromethane will contribute to refine models of the global atmospheric budget of chloromethane.
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Affiliation(s)
- Thierry Nadalig
- Equipe Adaptations et Interactions Microbiennes dans l'Environnement, UMR 7156 Université de Strasbourg - CNRS, 28 rue Goethe, Strasbourg, 67083, France
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Wuerfel O, Greule M, Keppler F, Jochmann MA, Schmidt TC. Position-specific isotope analysis of the methyl group carbon in methylcobalamin for the investigation of biomethylation processes. Anal Bioanal Chem 2013; 405:2833-41. [PMID: 23325400 DOI: 10.1007/s00216-012-6635-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 11/29/2012] [Accepted: 12/06/2012] [Indexed: 12/18/2022]
Abstract
In the environment, the methylation of metal(loid)s is a widespread phenomenon, which enhances both biomobility as well as mostly the toxicity of the precursory metal(loid)s. Different reaction mechanisms have been proposed for arsenic, but not really proven yet. Here, carbon isotope analysis can foster our understanding of these processes, as the extent of the isotopic fractionation allows to differentiate between different types of reaction, such as concerted (SN2) or stepwise nucleophilic substitution (SN1) as well as to determine the origin of the methyl group. However, for the determination of the kinetic isotope effect the initial isotopic value of the transferred methyl group has to be determined. To that end, we used hydroiodic acid for abstraction of the methyl group from methylcobalamin (CH3Cob) or S-adenosyl methionine (SAM) and subsequent analysis of the formed methyl iodide by gas chromatography (GC) isotope ratio mass spectrometry (IRMS). In addition, three further independent methods have been investigated to determine the position-specific δ (13)C value of CH3Cob involving photolytic cleavage with different additives or thermolytic cleavage of the methyl-cobalt bonding and subsequent measurement of the formed methane by GC-IRMS. The thermolytic cleavage gave comparable results as the abstraction using HI. In contrast, photolysis led to an isotopic fractionation of about 7 to 9 ‰. Furthermore, we extended a recently developed method for the determination of carbon isotope ratios of organometal(loid)s in complex matrices using hydride generation for volatilization and matrix separation before heart-cut GC and IRMS to the analysis of the low boiling partly methylated arsenicals, which are formed in the course of arsenic methylation. Finally, we demonstrated the applicability of this methodology by investigation of carbon fractionation due to the methyl transfer from CH3Cob to arsenic induced by glutathione.
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Affiliation(s)
- Oliver Wuerfel
- Instrumental Analytical Chemistry, University of Duisburg-Essen, Essen, Germany
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Gori Y, Wehrens R, Greule M, Keppler F, Ziller L, La Porta N, Camin F. Carbon, hydrogen and oxygen stable isotope ratios of whole wood, cellulose and lignin methoxyl groups of Picea abies as climate proxies. Rapid Commun Mass Spectrom 2013; 27:265-275. [PMID: 23239341 DOI: 10.1002/rcm.6446] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2012] [Revised: 10/10/2012] [Accepted: 10/19/2012] [Indexed: 06/01/2023]
Abstract
RATIONALE Carbon, hydrogen and oxygen (C, H and O) stable isotope ratios of whole wood and components are commonly used as paleoclimate proxies. In this work we consider eight different proxies in order to discover the most suitable wood component and stable isotope ratio to provide the strongest climate signal in Picea abies in a southeastern Alpine region (Trentino, Italy). METHODS δ(13)C, δ(18)O and δ(2)H values in whole wood and cellulose, and δ(13)C and δ(2)H values in lignin methoxyl groups were measured. Analysis was performed using an Isotopic Ratio Mass Spectrometer coupled with an Elemental Analyser for measuring (13)C/(12)C and a Pyrolyser for measuring (2)H/(1)H and (18)O/(16)O. The data were evaluated by Principal Component Analysis, and a simple Pearson's correlation between isotope chronologies and climatic features, and multiple linear regression were performed to evaluate the data. RESULTS Each stable isotope ratio in cellulose and lignin methoxyl differs significantly from the same stable isotope ratio in whole wood, the values begin higher in cellulose and lignin except for the lignin δ(2)H values. Significant correlations were found between the whole wood and the cellulose fractions for each isotope ratio. Overall, the highest correlations with temperature were found with the δ(18)O and δ(2)H values in whole wood, whereas no significant correlations were found between isotope proxies and precipitation. CONCLUSIONS δ(18)O and δ(2)H values in whole wood provide the best temperature signals in Picea abies in the northern Italian study area. Extraction of cellulose and lignin and analysis of other isotopic ratios do not seem to be necessary.
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Affiliation(s)
- Y Gori
- IASMA Research and Innovation Centre-Fondazione Edmund Mach, Via E. Mach 1, 38010, San Michele all'Adige, Italy.
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Polag D, Heuwinkel H, Laukenmann S, Greule M, Keppler F. Evidence of anaerobic syntrophic acetate oxidation in biogas batch reactors by analysis of 13C carbon isotopes. Isotopes Environ Health Stud 2013; 49:365-77. [PMID: 23781862 DOI: 10.1080/10256016.2013.805758] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Between 2008 and 2010 various batch experiments were carried out to study the stable carbon isotopic composition of biogas (CH4 and CO2) produced from (i) pure sludge and (ii) sludge including maize. From the evolution of the natural isotopic signature, a temporal change of methanogenic pathways could be detected for the treatment with maize showing that a dominance in acetotrophic methanogenesis was replaced by a mixture of hydrogenotrophic and acetotrophic methanogenesis. For pure sludge, hydrogenotrophic methanogenesis was the dominant or probably exclusive pathway. Experiments with isotopically labelled acetate (99% (13)CH3COONa and 99% CH3(13)COONa) indicated a significant contribution of syntrophic acetate oxidation (SAO) for all the investigated treatments. In the case of pure sludge, experiments from 2008 showed that acetate was almost entirely oxidised to CO2, i.e. acetotrophic methanogenesis was negligible. However, in 2010, the sludge showed a clear dominance in acetotrophic methanogenesis with a minor contribution by SAO indicating a significant change in the metabolic character. Our results indicate that SAO during anaerobic degradation of maize might be a significant process that needs to be considered in biogas research.
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Affiliation(s)
- Daniela Polag
- a Max-Planck-Institute for Chemistry , Mainz , Germany
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