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  • A combined tracer/evapotranspiration model approach estimates plant water uptake in native and non-native shrub-steppe communities

    Peer Reviewed Literature
    Water Isotope Analyzers

    Here we test an experimental approach that produces estimates of the location, timing and extent of water uptake by individual plant species in the field. A tracer injection experiment was used to estimate the proportion of active roots across soil depths. These proportions were multiplied by species-specific estimates of evapotranspiration. This approach was repeated in early- and late-season conditions in adjacent native- and non-native-dominated shrub-steppe plant communities. Resulting estimates of water uptake by depth were compared to soil water content.

  • A 2500-yr late Holocene multi-proxy record of vegetation and hydrologic changes from a cave guano-clay sequence in SW Romania

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    We provide sedimentological, geochemical, mineral magnetic, stable carbon isotope, charcoal, and pollen-based evidence from a guano/clay sequence in Gaura cu Muscă Cave (SW Romania), from which we deduced that from ~ 1230 BC to ~ AD 1240 climate oscillated between wet and dry. From ~ 1230 BC to AD 1000 the climate was wetter than the present, prompting flooding of the cave, preventing bats from roosting, and resulting in a slow rate of clay accumulation.

  • H2S interference on CO2 isotopic measurements using a Picarro G1101-i cavity ring-down spectrometer

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    Cavity ring-down spectrometers (CRDS) have the capacity to make isotopic measurements of CO2 where concentrations range from atmospheric (~ 400 ppm) to 6000 ppm. Following field trials, it has come to light that the spectrographic lines used for CO2 have an interference with elevated (higher than ambient) amounts of hydrogen sulfide (H2S), which causes significant depletions in the δ13C measurement by the CRDS.

  • Vapor hydrogen and oxygen isotopes reflect water of combustion in the urban atmosphere

    Peer Reviewed Literature
    Water Isotope Analyzers

    Anthropogenic modification of the water cycle involves a diversity of processes, many of which have been studied intensively using models and observations. Effective tools for measuring the contribution and fate of combustion-derived water vapor in the atmosphere are lacking, however, and this flux has received relatively little attention. We provide theoretical estimates and a first set of measurements demonstrating that water of combustion is characterized by a distinctive combination of H and O isotope ratios.

  • Arctic cyclone water vapor isotopes support past sea ice retreat recorded in Greenland ice

    Peer Reviewed Literature
    Water Isotope Analyzers

    Rapid Arctic warming is associated with important water cycle changes: sea ice loss, increasing atmospheric humidity, permafrost thaw, and water-induced ecosystem changes. Understanding these complex modern processes is critical to interpreting past hydrologic changes preserved in paleoclimate records and predicting future Arctic changes. Cyclones are a prevalent Arctic feature and water vapor isotope ratios during these events provide insights into modern hydrologic processes that help explain past changes to the Arctic water cycle.

  • Stable Isotope Analysis of Saline Water Samples on a Cavity Ring-Down Spectroscopy Instrument

    Peer Reviewed Literature
    Water Isotope Analyzers

    The analysis of the stable hydrogen and oxygen isotope composition of water using cavity ring-down spectroscopy (CRDS)
    instruments utilizing infrared absorption spectroscopy have been comprehensively tested. However, potential limitations of infrared

  • Interlaboratory assessment of nitrous oxide isotopomer analysis by isotope ratio mass spectrometry and laser spectroscopy: current status and perspectives

    Peer Reviewed Literature
    Gas Concentration Analyzers

    RATIONALE

    In recent years, research and applications of the N2O site-specific nitrogen isotope composition have advanced, reflecting awareness of the contribution of N2O to the anthropogenic greenhouse effect, and leading to significant progress in instrument development. Further dissemination of N2O isotopomer analysis, however, is hampered by a lack of internationally agreed gaseous N2O reference materials and an uncertain compatibility of different laboratories and analytical techniques.

  • Isotope-ratio infrared spectroscopy: a reliable tool for the investigation of plant-water sources?

    Peer Reviewed Literature
    Water Isotope Analyzers
    • Stable isotopes are extensively used as tracers for the study of plant-water sources. Isotope- ratio infrared spectroscopy (IRIS) offers a cheaper alternative to isotope-ratio mass spectroscopy (IRMS), but its use in studying plant and soil water is limited by the spectral interference caused by organic contaminants.
  • The effect of dissolved oxygen on N2O production by ammonia-oxidizing bacteria in an enriched nitrifying sludge

    Peer Reviewed Literature
    Water Isotope Analyzers

    Dissolved oxygen (DO) is commonly recognized as an important factor influencing nitrous oxide (N2O) production by ammonia-oxidizing bacteria (AOB). However, it has been difficult to separate the true effect of DO from that of nitrite, as DO variation often affects nitrite accumulation. The effect of DO on N2O production by an enriched nitrifying sludge, consisting of both AOB and nitrite-oxidizing bacteria (NOB), was investigated in this study. Nitrite accumulation was minimized by augmenting nitrite oxidation through the addition of an enriched NOB sludge.

  • Microwave extraction–isotope ratio infrared spectroscopy (ME-IRIS): a novel technique for rapid extraction and in-line analysis of δ18O and δ2H values of water in plants, soils and insects

    Peer Reviewed Literature
    Water Isotope Analyzers
     

    RATIONALE

    Traditionally, stable isotope analysis of plant and soil water has been a technically challenging, labour-intensive and time-consuming process. Here we describe a rapid single-step technique which combines Microwave Extraction with Isotope Ratio Infrared Spectroscopy (ME-IRIS).

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    Calibrated high-precision 17O-excess measurements using cavity ring-down spectroscopy with laser-current-tuned cavity resonance

    Peer Reviewed Literature
    Water Isotope Analyzers

    High-precision analysis of the 17O / 16O isotope ratio in water and water vapor is of interest in hydrological, paleoclimate, and atmospheric science applications. Of specific interest is the parameter 17O excess (Δ17O), a measure of the deviation from a‾linear relationship between 17O / 16O and 18O / 16O ratios.

  • CO2, CO, and CH4 measurements from tall towers in the NOAA Earth System Research Laboratory's Global Greenhouse Gas Reference Network: instrumentation, uncertainty analysis, and recommendations for future high-accuracy greenhouse gas monitoring efforts

    Peer Reviewed Literature
    Gas Concentration Analyzers

    A reliable and precise in situ CO2 and CO analysis system has been developed and deployed at eight sites in the NOAA Earth System Research Laboratory's (ESRL) Global Greenhouse Gas Reference Network. The network uses very tall (> 300 m) television and radio transmitter towers that provide a convenient platform for mid-boundary-layer trace-gas sampling. Each analyzer has three sample inlets for profile sampling, and a complete vertical profile is obtained every 15 min.

  • Multiscale observations of CO2, 13CO2, and pollutants at Four Corners for emission verification and attribution

    Peer Reviewed Literature
    Gas Concentration Analyzers

    There is a pressing need to verify air pollutant and greenhouse gas emissions from anthropogenic fossil energy sources to enforce current and future regulations. We demonstrate the feasibility of using simultaneous remote sensing observations of column abundances of CO2, CO, and NO2 to inform and verify emission inventories.

  • Airborne emission measurements of SO2 , NOx and particles from individual ships using a sniffer technique

    Peer Reviewed Literature
    Gas Concentration Analyzers

    A dedicated system for airborne ship emission measurements of SO2, NOx and particles has been developed and used from several small aircraft. The system has been adapted for fast response measurements at 1 Hz, and the use of several of the instruments is unique. The uncertainty of the given data is about 20% for SO2 and 24% for NOx emission factors.

  • Biodegradation measurements confirm the predictive value of the O:C-ratio for biochar recalcitrance

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    Suitable predictors of degradability are sought to support the identification of biochars with large potential to increase C sequestration in soils. We determined the biodegradation of 9 chars from hydrothermal carbonization and pyrolysis in two agricultural soils. The 200- and 115-day degradation correlated strongly with the O:C- and slightly with the H:C-atomic ratio of 9 and 14 biochars, respectively. Highest temperature treatment and ash content did not show similar correlations.

  • Composition of hydrothermal fluids and mineralogy of associated chimney material on the East Scotia Ridge back-arc spreading centre

    Peer Reviewed Literature
    Water Isotope Analyzers

    The East Scotia Ridge is an active back-arc spreading centre located to the west of the South Sandwich island arc in the Southern Ocean. Initial exploration of the ridge by deep-tow surveys provided the first evidence for hydrothermal activity in a back-arc setting outside of the western Pacific, and we returned in 2010 with a remotely operated vehicle to precisely locate and sample hydrothermal sites along ridge segments E2 and E9.

  • Hydrochemistry of the Hot Springs in Western Sichuan Province Related to the Wenchuan

    Peer Reviewed Literature
    Water Isotope Analyzers

    Hydrogeochemistry of 32 hot springs in the western Sichuan Province after the Wenchuan  8.0 earthquake was investigated by analyzing the concentrations of cation and anion and the isotopic compositions of hydrogen and oxygen. The water samples of the hot springs were collected four times from June 2008 to April 2010. Hydrogeochemical data indicated the water samples can be classified into 9 chemical types.

  • Hydrology and pore water chemistry in a permafrost wetland, Ilulissat, Greenland

    Peer Reviewed Literature
    Water Isotope Analyzers

    Hydrological and geochemical processes controlling the pore water chemistry in a permafrost wetland, with loam overlain by sphagnum peat, were investigated. The vertical distributions of dissolved Cl, and of pore water δ18O, appeared unrelated to ion freeze-out and isotope ice-water fractionation processes, respectively, dismissing solute freeze-out as a main control on the water chemistry. However, concentrations of major ions, others than Cl, generally increased with depth into the active layer. A conceptual model for water and solute movement in the active layer was derived.

  • Trimethylamine emissions in animal husbandry

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Degradation of plant material by animals is an important transformation pathway in the nitrogen (N) cycle. During the involved processes, volatile reduced alkaline nitro-gen compounds, mainly ammonia (NH3) and aliphatic amines such as trimethylamine (TMA), are formed. Today, animal husbandry is estimated to constitute a main source of aliphatic amines into the atmosphere with TMA being the main emitted compound. Here, we show how the interaction between faeces and urine in animal production sys-tems provides the primary source for agricultural TMA emissions.

  • On The Oxygen and Hydrogen Isotope Composition of Silage Water

    Peer Reviewed Literature
    Water Isotope Analyzers

    Silage is an important dietary water source that influences the oxygen and hydrogen isotopic composition of domestic herbivores and their products. Silage sampled fresh from the silo had18O- and 2H-depleted tissue water when compared with fresh pasture grass sampled around midday during the silage-making seasons. During exposure in the feed bunk, silage water became increasingly enriched in 18O and 2H.

  • Drought-Tolerance of Wheat Improved by Rhizosphere Bacteria from Harsh Environments: Enhanced Biomass Production and Reduced Emissions of Stress Volatiles

    Peer Reviewed Literature
    Water Isotope Analyzers

    Water is the key resource limiting world agricultural production. Although an impressive number of research reports have been published on plant drought tolerance enhancement via genetic modifications during the last few years, progress has been slower than expected. We suggest a feasible alternative strategy by application of rhizospheric bacteria coevolved with plant roots in harsh environments over millions of years, and harboring adaptive traits improving plant fitness under biotic and abiotic stresses.

  •  A new look at methane and nonmethane hydrocarbon emissions from oil and natural gas operations in the Colorado Denver-Julesburg Basin

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Emissions of methane (CH4) from oil and natural gas (O&G) operations in the most densely drilled area of the Denver-Julesburg Basin in Weld County located in northeastern Colorado are estimated for 2 days in May 2012 using aircraft-based CH4 observations and planetary boundary layer height and ground-based wind profile measurements. Total top-down CH4 emission estimates are 25.8 ± 8.4 and 26.2 ± 10.7 t CH4/h for the 29 and 31 May flights, respectively.

  • Airborne characterization of smoke marker ratios from prescribed burning

    Peer Reviewed Literature
    Gas Concentration Analyzers

    A Particle-into-Liquid Sampler – Total Organic Carbon and fraction collector sys-tem was flown aboard a Twin Otter aircraft sampling prescribed burning emis-sions in South Carolina in November 2011 to obtain smoke marker measure-ments. The fraction collector provided 2min time-integrated off-line samples for car-bohydrate (i.e., smoke markers levoglucosan, mannosan, galactosan) analysis by high-performance anion-exchange chromatography with pulsed amperometric detec-tion.

  • Detection of simulated leaks from geologically stored CO2 with 13C monitoring

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Precise methods for the detection of geologically stored CO2 within and above soil surfaces are an important component of the development of carbon capture and storage (CCS) under terrestrial environments. Although CO2 leaks are not expected in well-chosen and operated storage sites, monitoring is required by legislation and any leakage needs to be quantified under the EU Emissions Trading Directive.

  • Stable water isotope tracing through hydrological models for disentangling runoff generation processes at the hillslope scale

    Peer Reviewed Literature
    Water Isotope Analyzers

    Hillslopes are the dominant landscape components where incoming precipitation is transferred to become groundwater, streamflow or atmospheric water vapor. However, directly observing flux partitioning in the soil is almost impossible. Hydrological hills-lope models are therefore being used to investigate the involved processes.

  • A Comparison of In Situ Aircraft Measurements of Carbon Dioxide and Methane to GOSAT Data Measured Over Railroad Valley Playa, Nevada, USA

    Peer Reviewed Literature
    Gas Concentration Analyzers

    In this paper, we report the vertical profiles of CO2 and CH4 measured with a cavity ring-down spectrometer (CRDS) on a research aircraft from near-ground level to 8 km above mean sea level. The airborne platform employed in this paper is an Alpha Jet aircraft operated from NASA's Ames Research Center. Flights were undertaken to Railroad Valley, NV, USA, to coincide with overpasses of the Greenhouse Gases Observing Satellite (GOSAT).

  • A low-volume cavity ring-down spectrometer for sample-limited applications

    Peer Reviewed Literature
    Water Isotope Analyzers, Gas Concentration Analyzers, CRDS Instrumentation

    In atmospheric and environmental sciences, optical spectrometers are used for the measurements of greenhouse gas mole fractions and the isotopic composition of water vapor or greenhouse gases. The large sample cell volumes (tens of milliliters to several liters) in commercially available spectrometers constrain the usefulness of such instruments for applications that are limited in sample size and/or need to track fast variations in the sample stream.

  • Dissolved barium behavior in Louisiana Shelf waters affected by the Mississippi/Atchafalaya River mixing zone

    Peer Reviewed Literature
    Water Isotope Analyzers

    In order to better understand the constraints on the use of barium as a coastal paleo-freshwater tracer, we surveyed the dissolved Ba distribution in Louisiana Shelf waters, including the Mississippi (MR) and Atchafalaya (AR) River plumes, during May and November 2008, and June/July 2009, which represent high, low and intermediate river discharges, respectively. Dissolved Ba was found dominantly in the <0.02 μm fraction, with no significant contribution from the 0.02 - 0.45 μm colloidal size fraction.

  • Oxygen isotope signatures of transpired water vapor: the role of isotopic non-steady-state transpiration under natural conditions

    Peer Reviewed Literature
    Water Isotope Analyzers
    • The oxygen isotope signature of water is a powerful tracer of water movement from plants to the global scale.
  • Evolution of the complex refractive index in the UV spectral region in ageing secondary organic aerosol

    Peer Reviewed Literature
    Gas Concentration Analyzers

    The chemical and physical properties of secondary organic aerosol (SOA) formed by the photochemical degradation of biogenic and anthropogenic volatile organic compounds (VOC) are as yet still poorly constrained. The evolution of the complex refractive index (RI) of SOA, formed from purely biogenic VOC and mixtures of biogenic and anthropogenic VOC, was studied over a diurnal cycle in the SAPHIR photochemical outdoor chamber in Jülich, Germany. The correlation of RI with SOA chemical and physical properties such as oxidation level and volatility was examined.

  • Elucidating the sources and mechanisms of groundwater salinization in the Ziz Basin of southeastern Morocco

    Peer Reviewed Literature
    Water Isotope Analyzers

    In the Ziz Basin, located in arid area in southeastern Morocco, surface waters are scarce and local populations are entirely dependent on groundwater resources for drinking and irrigation. In order to evaluate the main factors controlling the origin and salinization of groundwater resources, we have investigated the chemical and stable isotope compositions of groundwater and surface water in different areas in the Ziz basin, upstream and downstream from the Hassan Addakhil dam, which is the major man-made reservoir in the basin.

  • An instrumented sample holder for time-lapse micro-tomography measurements of snow under advective airflow

    Peer Reviewed Literature
    Water Isotope Analyzers

    An instrumented sample holder was developed for time-lapse micro-tomography of snow samples to enable in-situ nondestructive spatial and temporal measurements under controlled advective airflows, temperature gradients, and air humidities. The design was aided by computational fluid dynamics simulations to evaluate the airflow uniformity across the snow sample. Morphological and mass transport properties were evaluated during a 4 day test run. This instrument allows the experimental characterization of metamorphism of snow undergoing structural changes with time.

  • Spatial analysis of hydrogen and oxygen stable isotopes (“isoscapes”) in ground water and tap water across South Africa

    Peer Reviewed Literature
    Water Isotope Analyzers

    Stable isotopes in water (δ2H and δ18O) are important indicators of hydrological and ecological pattern and process. δ2H and δ18O of water are incorporated into geological and biological systems in a predictable manner and have been used extensively as tracers in hydrological, ecological and forensic studies. Physical processes result in spatial variation of δ2H, δ18O in water across the landscape (so-called “isoscapes”) and provide the basis for hydrological, ecological, archaeological and forensic studies.

  • Stable isotopes track biogeochemical processes under seasonal ice cover in a shallow, productive lake

    Peer Reviewed Literature
    Water Isotope Analyzers

    Biogeochemical dynamics under seasonal ice cover were investigated in the shallow (<10 m) water column of highly productive Georgetown Lake, western Montana, USA. This high altitude (1,800 m) reservoir is well-mixed in summer, but becomes strongly stratified under ice cover (mid-November–mid-May).

  • Causes of increasing ozone and decreasing carbon monoxide in springtime at the Mt. Bachelor Observatory from 2004 to 2013

    Peer Reviewed Literature
    Gas Concentration Analyzers

    We report trends in springtime ozone (O3) and carbon monoxide (CO) at the Mt. Bachelor Observatory (MBO) in central Oregon, U.S.A. from 2004 to 2013. Over the 10-year period the median and 95th percentile springtime O3 increased by 0.76 ± 0.61 ppbv yr−1 (1.7 ± 1.4% yr−1) and 0.87 ± 0.73 ppbv yr−1 (1.5 ± 1.2% yr−1), respectively. These trends are consistent with reported positive trends in springtime O3 in the western U.S.

  • Influence of tree cover on herbaceous layer development and carbon and water fluxes in a Portuguese cork-oak woodland

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    Facilitation and competition between different vegetation layers may have a large impact on small-scale vegetation development. We propose that this should not only influence overall herbaceous layer yield but also species distribution and understory longevity, and hence the ecosystems carbon uptake capacity especially during spring.

  • Triple water‐isotopologue record from WAIS Divide, Antarctica: controls on glacial‐interglacial changes in 17Oexcess of precipitation

    Peer Reviewed Literature
    Water Isotope Analyzers

    Measurements of the 17Oexcess of H2O were obtained from ice cores in West and East Antarctica. Combined with previously-published results from East Antarctica, the new data provide the most complete spatial and temporal view of Antarctic 17Oexcess to date. There is a steep spatial gradient of 17Oexcess in present-day precipitation across Antarctica, with higher values in marine-influenced regions, and lower values in the East Antarctic interior.

  • In situ measurement of atmospheric CO2 at the four WMO/GAW stations in China

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Atmospheric carbon dioxide (CO2) mole fractions were continuously measured from January 2009 to December 2011 at four atmospheric observatories in China using cavity ring-down spectroscopy instruments. The stations are Lin'an (LAN), Longfengshan (LFS), Shangdianzi (SDZ), and Waliguan (WLG), which are regional (LAN, LFS, SDZ) or global (WLG) measurement stations of the World Meteorological Organization's Global Atmosphere Watch program (WMO/GAW). LAN is located near the megacity of Shanghai, in China's economically most developed region.

  • Inferences from CO2 and CH4 concentration profiles at the Zotino Tall Tower Observatory (ZOTTO) on regional summertime ecosystem fluxes

    Peer Reviewed Literature
    Gas Concentration Analyzers

    The Siberian region is still sparsely covered by ecosystem observatories, which motivates the exploitation of existing data sets to gain spatially and temporally better-resolved carbon budgets. The Zotino Tall Tower Observatory (ZOTTO; 60°48' N, 89°21' E) observations of CO2 and CH4 mole fractions as well as meteorological parameters from six different heights up to 301 m allow for an additional estimate of surface–atmosphere fluxes of CO2 and CH4 for the middle Siberian region beginning 2009.

  • Distributions and assemblages of microbial communities along a sediment core retrieved from a potential hydrate-bearing region offshore southwestern Taiwan

    Peer Reviewed Literature
    Water Isotope Analyzers

    Assessing the impacts of methane released from hydrate-bearing environments on global carbon cycling would require detailed insights into the distributions and capacities of microbial communities at different horizons of sediment column. In this study, we conducted geochemical, gene abundance and diversity analyses for a sediment core retrieved from a potential hydrate-bearing region off southwestern Taiwan.

  • Tracing fossil fuel CO2 using Δ14C in Xi’an City, China

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    Radiocarbon can be used to trace fossil fuel CO2 (CO2ff) in the atmosphere, because radiocarbon has been depleted in fossil fuels. Here we present our study on the spatial distribution and temporal variations of CO2ff in Xi'an City, China using Δ14C of both green foxtail (Setaria viridis, L. Beauv.) leaf samples and urban air samples collected in the recent years.

  • Estimation of regional background concentration of CO2 at Lin'an Station in Yangtze River Delta, China

    Peer Reviewed Literature
    Gas Concentration Analyzers

    A new method of extracting regional background concentration of CO2 in Yangtze River Delta was established based on the observations of both black carbon concentration and meteorological parameters. The concentrations of CO2 and black carbon were observed at Lin'an regional background station from 2009 to 2011. The regional background concentration of CO2 in Yangtze River Delta was obtained by means of this new method, and the impact of human activities on CO2 concentration in this area was also assessed.

  • Hydrochemistry and isotopic characteristics of non-volcanic hot springs around the Miocene Kofu granitic complex surrounding the Kofu Basin in the South Fossa Magna region, central Honshu, Japan

    Peer Reviewed Literature
    Water Isotope Analyzers

    Chemical and stable isotopic compositions (δD, δ18O, and δ34S) of non-volcanic hot spring waters around the Miocene Kofu granitic complex surrounding the Kofu basin in the South Fossa Magna region of central Honshu, Japan, were analyzed in order to investigate water–rock interactions and to determine the origin and sulfur isotopic characteristics of their trace amounts of SO4 2–ion.

  • Temperature sensitivity of soil and root respiration in contrasting soils

    Peer Reviewed Literature
    Carbon Isotope Analyzers

     

    Background and aims

    Positive relationships between temperature and soil respiration rate are widely observed, but it remains unclear if the relationships are due to increases in soil organic matter mineralisation (R om), or in root and rhizosphere respiration (R roots), or increases in both. This study aims to determine the relative sensitivity of R om and R roots to temperature in soils with differing properties.

  • A 2 year record of atmospheric mercury species at a background Southern Hemisphere station on Amsterdam Island

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Scarcity of mercury species records in the Southern Hemisphere is a critical weak point for the development of appropriate modeling and regulation scenarios. Under the framework of the “Global Mercury Observation System” (GMOS) project, a monitoring station has been set up on Amsterdam Island (37_480 S, 77_340 5 E) in the remote southern Indian Ocean. For the first time in the Southern Hemisphere, a 2 year record of gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and particle-bound mercury (PBM) is presented.

  • Recent climate and ice-sheet changes in West Antarctica compared with the past 2,000 years

    Peer Reviewed Literature
    Water Isotope Analyzers

    Changes in atmospheric circulation over the past five decades have enhanced the wind-driven inflow of warm ocean water onto the Antarctic continental shelf, where it melts ice shelves from below. Atmospheric circulation changes have also caused rapid warming

  • Novel Use of Cavity Ring-down Spectroscopy to Investigate Aquatic Carbon Cycling from Microbial to Ecosystem Scales

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Development of cavity ring-down spectroscopy (CRDS) has enabled real-time monitoring of carbon stable isotope ratios of carbon dioxide and methane in air. Here we demonstrate that CRDS can be adapted to assess aquatic carbon cycling processes from microbial to ecosystem scales.

  • Vegetation induced changes in the stable isotope composition of near surface humidity

    Peer Reviewed Literature
    Water Isotope Analyzers

    Obtaining the d-excess parameter from oxygen and hydrogen stable isotope composition of meteoric waters has the potential power to reconstruct changes in atmospheric water pools (e,g. sources, origins and overall balance) and the climatic conditions that prevail during surface evaporation. Recently, plant and ecosystem scientists turned their attention using d-excess information to inform questions at these scales.

  • Reliability and quality of water isotope data collected with a low-budget rain collector

    Peer Reviewed Literature
    Water Isotope Analyzers

    RATIONALE:

    Low-budget rain collectors for water isotope analysis, such as the 'ball-in-funnel type collector' (BiFC), are widely used in studies on stable water isotopes of rain. To date, however, an experimental quality assessment of such devices in relation to climatic factors does not exist.

    METHODS:

  • Sulfate attack - Reaction mechanisms revealed by a multi proxy approach

    Peer Reviewed Literature
    Water Isotope Analyzers

    The destructive effects of sulfate attack on concrete structures are well known, but the reaction paths and mechanisms that cause the deterioration are still under debate. The aim of this study is to contribute to a deeper understanding on investigating concrete damage by introducing a novel and promising multi proxy approach method. The methodology comprises advanced mineralogical and hydro-geochemical methods as well as stable isotope signals.