Markus Greule

Universität Heidelberg · Institute of Earth Sciences

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 (CH3I) as the reference material to normalise...

Chloromethane (CH3Cl) is the most important natural input of reactive chlorine to the stratosphere, contributing about 16 % to stratospheric ozone depletion. Due to the phase-out of anthropogenic emissions of chlorofluorocarbons, CH3Cl will largely control future levels of stratospheric chlorine. The tropical rainforest is commonly assumed to be th...

Vanilla flavour is highly vulnerable to economically motivated adulteration as the main component vanillin can be derived by much cheaper production methods than by the extraction from vanilla pods. The δ¹³C ranges for synthetic vanillin from petroleum and C3 plants are depleted in comparison to the reported δ¹³C range for vanillin from vanilla orc...

Methoxy groups (OCH₃) of plants show specific stable carbon and hydrogen isotope patterns that are used for applications in biogeochemical, atmospheric, paleoclimatic and food research. The method of choice for determining stable hydrogen and carbon isotope values of methoxy groups (δ²H_(OCH₃) and δ¹³C_(OCH₃) values) is the conversion to gaseous io...

Stable hydrogen isotope values of wood lignin methoxy groups (δ²HLM) are increasingly applied to reconstruct the stable hydrogen isotope composition of precipitation (δ²Hprecip) and mean annual temperatures (MAT) of mid latitudes regions. Recently, the analytical procedure for measuring δ²HLM values was considerably improved by the availability of...

Aquatic ecosystems play an important role in global methane cycling and many field studies have reported methane supersaturation in the oxic surface mixed layer (SML) of the ocean and in the epilimnion of lakes. The origin of methane formed under oxic condition is hotly debated and several pathways have recently been offered to explain the “methane...

Chloromethane (CH3Cl) is the most abundant natural chlorinated organic compound in the atmosphere playing an important role in catalyzing stratospheric ozone loss. Vegetation emits the largest amounts of CH3Cl to the atmosphere but its source strength is highly uncertain leading also to large uncertainties in the global budget of CH3Cl. Triple‐elem...

Aquatic ecosystems play an important role in global methane cycling and many field studies have reported methane supersaturation in the oxic surface mixed layer (SML) of the ocean and in the epilimnion of lakes. The origin of methane formed under oxic condition is hotly debated and several pathways have recently been offered to explain the ‘methane...

The Qinling Mountains (Qinling Mts.) are characterized as a distinct transition of bioclimatic zones along the north-south geographic boundary in China. Although ongoing global warming may affect the growth of most tree species across elevation gradients, the effect of modern warming on the stable hydrogen isotopes of tree-ring wood is still unknow...

Methane (CH4) emissions from aquatic systems have recently been comprised to account for up to 50% of global CH4 emissions, with lakes representing one of the largest CH4 sources within this pool. However, there is large uncertainty associated with CH4 emissions from freshwater environments to the atmosphere, because of a lack of understanding in t...

Stable hydrogen and carbon isotope ratios of wood lignin methoxy groups (δ13C and δ2H values) have been shown to be reliable proxies of past temperature variations. Previous studies showed that δ2H values even work in temperate environments where classical tree-ring width and maximum latewood density measurements are less successful for climate rec...

In this study we explored the potential benefits of triple element isotope analysis (2H, 13C, 37Cl) of CH3Cl emitted by royal fern (Osmunda regalis) and degradation by a club moss (Selaginella kraussiania). CH3Cl emitted by royal fern showed depleted isotopic values for all elements compared to anthropogenically produced CH3Cl which bodes well for...

Stable hydrogen and carbon isotope ratios of wood lignin methoxy groups (δ13CLM and δ2HLM values) have been shown to be reliable proxies of past temperature variations. Previous studies showed that δ2HLM values even work in temperate environments where classical tree-ring width and maximum latewood density measurements are less skilful. Here, we an...

Methane (CH4) is the most abundant organic compound in the atmosphere and is emitted from many biotic and abiotic sources. Recent studies have shown that CH4 production occurs under aerobic conditions in eukaryotes, such as plants, animals, algae, and saprotrophic fungi. Saprotrophic fungi play an important role in nutrient recycling in terrestrial...

Precipitation extremes with devastating socioeconomic consequences within the South American Monsoon System (SAMS) are expected to become more frequent in the near future. The complexity in SAMS behaviour, however, poses severe challenges for reliable future projections. Thus, robust paleo-monsoon records are needed to constrain the high spatiotemp...

Methane (CH4) is the most abundant organic compound in the atmosphere with emissions from many biotic and abiotic sources. Recent studies have shown that CH4 production occurs under aerobic conditions in eukaryotes such as plants, animals, algae and saprotrophic fungi. Saprotrophic fungi play an important role in nutrient recycling in terrestrial e...

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...

Stable hydrogen isotope ratios of lignin methoxyl groups (δ²HLM) of wood have been shown to reflect climate-sensitive δ²H values of precipitation (δ²Hprecip). However, a detailed calibration study between high-resolution δ²HLM and δ²Hprecip data has not been performed yet. Here, we present annually resolved δ²HLM values from nine tree-ring series (...

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 chlori...

Stable hydrogen isotopes ratios of lignin methoxyl groups (expressed as δ2HLM) of wood have been shown to reflect the climate-sensitive δ2H values of precipitation (expressed as δ2Hprecip) modulated by a large uniform negative isotope fractionation. However, a detailed calibration study among temporal variabilities of δ2HLM in tree-ring series, sit...

Chloromethane (CH3Cl) is the most important natural input of reactive chlorine to the stratosphere, contributing about 16% to stratospheric ozone depletion. Due to the phase out of anthropogenic emissions of chlorofluorocarbons, CH3Cl will largely control future levels of stratospheric chlorine. The tropical rainforest is commonly assumed to be the...

Three well-preserved mummified wood specimens have been excavated from three earliest Eocene (~55.5, 55.2 and 53.3 Ma) kimberlite pipes in the subarctic Northwest Territories, Canada (~64°N). Each specimen contained multi-decadal length tree-ring series and allowed measurements of stable hydrogen isotope ratios (δ²H values) of the lignin methoxyl g...

Chloromethane (CH3Cl) is an important provider of chlorine to the stratosphere but detailed knowledge of its budget is missing. Stable isotope analysis is a potentially powerful tool to constrain CH3Cl flux estimates. The largest degree of isotope fractionation is expected to occur for deuterium in CH3Cl in the hydrogen abstraction reactions with i...

A fast and sensitive method for the continuous determination of methane (CH4) and its stable carbon isotopic values (δ13C‐CH4) in surface waters was developed by applying a vacuum to a gas/liquid exchange membrane and measuring the extracted gases by a portable cavity ring‐down spectroscopy analyser (M‐CRDS). The M‐CRDS was calibrated and character...

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 fer...

Chloromethane (CH 3 Cl, methyl chloride) is the most abundant volatile halocarbon in the atmosphere and involved in stratospheric ozone depletion. The global CH 3 Cl budget, and especially the CH 3 Cl sink from microbial degradation in soil, still involves large uncertainties. These may potentially be resolved by a combination of stable isotope ana...

Chloromethane (CH3Cl) is an important provider of chlorine to the stratosphere but yet lacks detailed knowledge of its budget. Stable isotope analysis is potentially a powerful tool to constrain CH3Cl flux estimates. The largest degree of isotope fractionation is expected to occur for deuterium in CH3Cl in the hydrogen abstraction reactions with it...

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...

Rationale: In this study, we tested stable hydrogen isotope ratios of wood lignin methoxyl groups (δ (2) 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 δ(2) H values from wood. Methods: W...

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 composit...

Originating from the seedpods of orchids, Vanilla belongs to the most widely appreciated flavours worldwide. Besides the seedpods (beans) also Vanilla extracts and isolated vanillin as the major characteristic aroma compound are commercially used. Different consumer demands and national regulations require appropriate quality control of products ar...

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 w...

Our understanding of African paleoclimate/hydrological history is mainly based on lake level and lake sediment studies. It improved during the last decade thanks to emerging stable isotope techniques such as compound-specific deuterium analysis of sedimentary leaf wax biomarkers (δ²Hleaf-wax). Here we present the results from a multi-proxy biomarke...

A new, high temporal and spatial resolution, in-situ method for the fast and precise determination of methane (CH4) concentration and its δ13C isotope value (δ13C-CH4) in water was developed. Methane is extracted from water by the application of a vacuum to a membrane gas/liquid exchange module and analysed by a portable cavity ring-down spectrosco...

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 δ(2)H values) of lignin...

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. I...

In this study, a barely used method to measure δ 13 C values from lignin methoxyl groups (δ 13 C methoxyl) of tree‐ rings is applied to high alpine larch trees to test their potential as a climate proxy. Thirty-seven larch trees (Larix decidua Mill.) were sampled at a tree line site near Simplon Village in the Valais/Switzerland. Samples were used...

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...

Comment on: "Authenticity and Traceability of Vanilla Flavors by Analysis of Stable Isotopes of Carbon and Hydrogen".

When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued, not only about their contribution to the global methane budget, but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of...

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 h...

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 u...

In the environment, the methylation of metal(loid)s is a widespread phenomenon, which enhances both biomobil-ity 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...

Controversy continues as to whether chloromethane (CH3Cl) detected during pyrolysis of Martian soils by the Viking and Curiosity Mars landers is indicative of organic matter indigenous to Mars. Here we demonstrate CH3Cl release (up to 8 μg/g) during low temperature (150-400°C) pyrolysis of the carbonaceous chondrite Murchison with chloride or perch...

When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued, not only about their contribution to the global methane budget, but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of...

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...

Stable hydrogen isotope ratios (dD values) of methoxyl groups in lignin and pectin from a variety of plant types from dif-ferent locations have been shown to mirror dD values of precipitation, with a mean uniform isotopic fractionation. Since dD in precipitation is mainly influenced by climatic conditions, including temperature, evaporation and pre...

Stable hydrogen isotope ratios (δD values) of methoxyl groups in a variety of plant types from different locations have been shown to record δD values of precipitation, with a mean uniform isotopic fractionation. Since δD in precipitation is mainly influenced by climatic conditions, including temperature, evaporation and precipitation amount, metho...

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,...

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 showin...

In the environment, the methylation of metal(loid)s is a widespread phenomenon, which enhances both biomobil-ity 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...

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...

Methane in the biosphere is mainly produced by prokaryotic methanogenic archaea, biomass burning, coal and oil extraction, and to a lesser extent by eukaryotic plants. Here we demonstrate that saprotrophic fungi produce methane without the involvement of methanogenic archaea. Fluorescence in situ hybridization, confocal laser-scanning microscopy an...