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  • 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.

  • Coastal aquifer system in late Pleistocene to Holocene deposits at Horonobe in Hokkaido, Japan

    Peer Reviewed Literature
    Water Isotope Analyzers

    The groundwater flow systems and chemistry in the deep part of the coastal area of Japan have attracted attention over recent decades due to government projects such as geological disposal of radioactive waste. However, the continuous groundwater flow system moving from the shallow to deep parts of the sedimentary soft rock has not yet been characterized.

  • Recent accumulation variability in northwest Greenland from ground-penetrating radar and shallow cores along the Greenland Inland Traverse

    Peer Reviewed Literature
    Water Isotope Analyzers

    Accumulation is a key parameter governing the mass balance of the Greenland ice sheet. Several studies have documented the spatial variability of accumulation over wide spatial scales, primarily using point data, remote sensing or modeling. Direct measurements of spatially extensive, detailed profiles of accumulation in Greenland, however, are rare. We used 400 MHz ground-penetrating radar along the 1009 km route of the Greenland Inland Traverse from Thule to Summit during April and May of 2011, to image continuous internal reflecting horizons.

  • Stable Isotope Analysis of Precipitation Samples Obtained via Crowdsourcing Reveals the Spatiotemporal Evolution of Superstorm Sandy

    Peer Reviewed Literature
    Water Isotope Analyzers

    Extra-tropical cyclones, such as 2012 Superstorm Sandy, pose a significant climatic threat to the northeastern United Sates, yet prediction of hydrologic and thermodynamic processes within such systems is complicated by their interaction with mid-latitude water patterns as they move poleward. Fortunately, the evolution of these systems is also recorded in the stable isotope ratios of storm-associated precipitation and water vapor, and isotopic analysis provides constraints on difficult-to-observe cyclone dynamics.

  • Carbon Sequestration and Fertility after Centennial Time Scale Incorporation of Charcoal into Soil

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    The addition of pyrogenic carbon (C) in the soil is considered a potential strategy to achieve direct C sequestration and potential reduction of non-CO2 greenhouse gas emissions. In this paper, we investigated the long term effects of charcoal addition on C sequestration and soil physico-chemical properties by studying a series of abandoned charcoal hearths in the Eastern Alps of Italy established in the XIX century. This natural setting can be seen as an analogue of a deliberate experiment with replications.

  • CO2 and CH4 in sea ice from a subarctic fjord

    Peer Reviewed Literature
    Gas Concentration Analyzers

    We present CH4 concentration [CH4] and the partial pressure of CO2 (pCO2) in bulk sea ice from subarctic, land-fast sea ice in the Kapisillit fjord, Greenland. The bulk ice [CH4] ranged from 1.8 to 12.1 nmol L−1, which corresponds to a partial pressure range of 3 to 28 ppmv. This is markedly higher than the average atmospheric methane content of 1.9 ppmv. Most of the trapped methane within the sea ice was evidently contained inside bubbles, and only a minor portion was dissolved in the brine.

  • Understanding mean transit times in Andean tropical montane cloud forest catchments: combining tracer data, lumped parameter models and uncertainty analysis

    Peer Reviewed Literature
    Water Isotope Analyzers

    Weekly samples from surface waters, springs, soil water and rainfall were collected in a 76.9 km2 mountain rain forest catchment and its tributaries in southern Ecuador. Time series of the stable water isotopes δ18O and δ2H were used to calculate mean transit times (MTTs) and the transit time distribution functions (TTDs) solving the convolution method for seven lumped parameter models.

  • An attempt at estimating Paris area CO2 emissions from atmospheric concentration measurements

    Peer Reviewed Literature
    Gas Concentration Analyzers

    Atmospheric concentration measurements are used to adjust the daily to monthly budget of CO2 emissions from the AirParif inventory of the Paris agglomeration. We use 5 atmospheric monitoring sites including one at the top of the Eiffel tower. The atmospheric inversion is based on a Bayesian approach, and relies on an atmospheric transport model with a spatial resolution of 2 km with boundary conditions from a global coarse grid transport model.

  • Toward a better understanding and quantification of methane emissions from shale gas development

    Peer Reviewed Literature
    Gas Concentration Analyzers

    The identification and quantification of methane emissions from natural gas production has become increasingly important owing to the increase in the natural gas component of the energy sector. An instrumented aircraft platform was used to identify large sources of methane and quantify emission rates in southwestern PA in June 2012. A large regional flux, 2.0–14 g CH4 s−1 km−2, was quantified for a ∼2,800-km2 area, which did not differ statistically from a bottom-up inventory, 2.3–4.6 g CH4 s−1 km−2.

  • Drilling and sampling a natural CO2 reservoir: Implications for fluid flow and CO2-fluid-rock reactions during CO2 migration through the overburden

    Peer Reviewed Literature
    Water Isotope Analyzers

    This paper presents the initial results of a scientific drilling project to recover core and pressurized fluid samples from a natural CO2 reservoir, near the town of Green River, Utah. The drilling targeted a stacked sequence of CO2-charged Jurassic sandstone reservoirs and caprocks, situated adjacent to a CO2-degassing normal fault. This site has actively leaked CO2 from deep supercritical CO2 reservoirs at depth > 2 km within the basin for over 400,000 years.

  • Stable isotopes in river waters in the Tajik Pamirs: regional and temporal characteristics

    Peer Reviewed Literature
    Water Isotope Analyzers

    The Gunt River catchment in the Central Pamirs is a representative of the headwater catchments of the Aral Sea Basin. It covers 14,000 km2, spanning altitudes between 2000 and 6700 m a.s.l. In a monitoring network, water samples were taken at 30 sampling points every month and analysed for the stable water isotopes (18O and 2H). Our first results show δ2H values in the range from−131.2 to−94.9 ‰ and δ18O values from−18.0 to−14.0 ‰.

  • A first chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core

    Peer Reviewed Literature
    Gas Concentration Analyzers

    A stratigraphy-based chronology for the North Greenland Eemian Ice Drilling (NEEM) ice core has been derived by transferring the annual layer counted Greenland Ice Core Chronology 2005 (GICC05) and its model extension (GICC05modelext) from the NGRIP core to the NEEM core using 787 match points of mainly volcanic origin identified in the electrical conductivity measurement (ECM) and dielectrical profiling (DEP) records.

  • Paleoclimate record in the Nubian Sandstone Aquifer, Sinai Peninsula, Egypt

    Peer Reviewed Literature
    Water Isotope Analyzers

    Sixteen groundwater samples collected from production wells tapping Lower Cretaceous Nubian Sandstone and fractured basement aquifers in Sinai were analyzed for their stable isotopic compositions, dissolved noble gas concentrations (recharge temperatures), tritium activities, and 14C abundances.

  • Origin and evolution characteristics of geothermal water in the Niutuozhen geothermal field, North China Plain

    Peer Reviewed Literature
    Water Isotope Analyzers

    Statistical study of analyses of water from 43 samples from geothermal wells, three groundwater wells, and one sample of local rainwater along with rainwater data from the Global Network of Isotopes in Precipitation has been used to identify the origin and evolution of geothermal water in the Niutuozhen (牛驼镇) geothermal field and estimate the renewability rate of its geothermal resource.

  • Performance assessment of a cavity ring-down laser spectrometer: achieving better precision and accuracy in the measurement of δ18O and δ2H in liquid water samples

    Peer Reviewed Literature
    Water Isotope Analyzers

    The development of new isotopic laser-based analyzers currently represents a clear alternative to conventional isotope ratio mass spectrometers. However, this analytical technique also suffers some disadvantages such as the memory effect, problems related to the overall stability of the equipment and other issues associated with the injection system, essentially regarding the syringe's longevity. This paper aims to minimize these disadvantages in order to increase the overall performance, in terms of precision and accuracy, of these kinds of analyzers.

  • Spatial and Temporal Variation of Stable Isotopes in Precipitation across Costa Rica: An Analysis of Historic GNIP Records

    Peer Reviewed Literature
    Water Isotope Analyzers

    The location of Costa Rica on the Central American Isthmus creates unique microclimate systems that receive moisture inputs directly from the Caribbean Sea and the Pacific Ocean. In Costa Rica, stable isotope monitoring was conducted by the International Atomic Energy Agency and the World Meteorological Association as part of the worldwide effort entitled Global Network of Isotopes in Precipitation. Sampling campaigns were mainly comprised of monthly-inte- grated samples during intermittent years from 1990 to 2005.

  • Guano-derived d13C-based paleo-hydroclimate record from Gaura cu Musca Cave, SW Romania

    Peer Reviewed Literature
    Carbon Isotope Analyzers

    The δ13C values of 23 unevenly spaced guano samples from a 17-cm long clay sediment profile in Gaura cu Musca Cave (GM), in SW Romania, made it possible to preliminarily characterize the Medieval Warm Period summer hydroclimate regime. The beginning of the sequence (AD 990) was rather wet for more than a century, before becoming progressively drier.

  • A multitower measurement network estimate of California’s methane emissions

    Peer Reviewed Literature
    Gas Concentration Analyzers

    We present an analysis of methane (CH4) emissions using atmospheric observations from five sites in California’s Central Valley across different seasons (September 2010 to June 2011).

  • The nocturnal water cycle in an open-canopy forest

    Peer Reviewed Literature
    Water Isotope Analyzers

    The movement of moisture into, out-of, and within forest ecosystems is modulated by feedbacks that stem from processes which couple plants, soil, and the atmosphere. While an understanding of these processes has been gleaned from Eddy Covariance techniques, the reliability of the method suffers at night because of weak turbulence.

  • A test of the advection-condensation model for subtropical water vapor using stable isotopologue observations from Mauna Loa Observatory, Hawaii

    Peer Reviewed Literature
    Water Isotope Analyzers

    Subtropical humidity plays a critical role in the radiative balance of the planet, and there is a need for adequate description of the controls on water vapor distributions. This study tests whether an advection-condensation model, combined with Rayleigh distillation, can describe observed humidity and water vapor isotope ratios of the subtropical free troposphere. A field campaign, from 9 October to 6 November, 2008, included continuous in situ measurement of water vapor stable isotope ratios at the NOAA Mauna Loa Observatory (MLO), Hawaii.

  • Root niche partitioning among grasses, saplings, and trees measured using a tracer technique

    Peer Reviewed Literature
    Water Isotope Analyzers

    Niche partitioning of resources by plants is believed to be a fundamental aspect of plant coexistence and biogeochemical cycles; however, measurements of the timing and location of resource use are often lacking because of the difficulties of belowground research. To measure niche partitioning of soil water by grasses, planted saplings, and trees in a mesic savanna (Kruger National Park, South Africa), we injected deuterium oxide into 102,000 points in 15, 154-m2 plots randomly assigned to one of five depths (0–120 cm) and one of three time periods during the 2008/2009 growing season.

  • Water isotopic variability in response to mesoscale convective system over the tropical ocean

    Peer Reviewed Literature
    Water Isotope Analyzers

    In tropical regions, the empirical negative relationship between the isotopic content of precipitation and rainfall amount, known as the 'amount effect', has been used as a rationale for paleo-hydroclimate reconstruction from isotope records. However, there is still no comprehensive physical explanation for this empirical effect. Here, we reconsider the well-known amount effect using newly available isotope data for both surface water vapor and precipitation obtained from shipboard observations.

  • Estimation of soil water evaporative loss after tillage operation using the stable isotope technique

    Peer Reviewed Literature
    Water Isotope Analyzers

    Application of stable isotopes in soil studies has improved quantitative evaluation of evaporation and other hydrological processes in soil. This study was carried out to determine the effect of tillage on evaporative loss of water from the soil. Zero tillage and conventional tillage were compared. Suction tubes were installed for soil water collection at the depths 0.15, 0.50, and 1.0 m by pumping soil water with a peristaltic pump. Soil water evaporation was estimated using stable isotopes of water.

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

    Peer Reviewed Literature
    Water Isotope Analyzers

    Obtaining the d-excess parameter from the oxygen (O) and hydrogen (H) 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. Only recently have plant and ecosystem scientists turned their attention to using d-excess information to inform questions at these scales.

  • A synthesis of hydrogen isotope variability and its hydrological significance at the Qinghai–Tibetan Plateau

    Peer Reviewed Literature
    Water Isotope Analyzers

    Hydrogen isotope ratios of sedimentary biomarkers are known to record the climatic variability in terrestrial and marine environments. However, there is still a lack of calibration studies that can quantitatively retrace the driving forces, especially at the Tibetan Plateau. Here, we elaborate the actual influence of environmental parameters such as temperature, evapotranspiration, salinity and biosynthetic fractionation on δD values of n-alkanes.

  • Monthly d18O, dD and Cl- characteristics of precipitation in the Ndop plan, Northwest Cameroon: Baseline data

    Peer Reviewed Literature
    Water Isotope Analyzers

    Knowledge of stable isotopes and chemical tracers in meteoric water has been used as a valuable tool in various environmental studies. A systematic monthly sampling of precipitation, in the Ndop plain, was carried out to generate basic data on δ18, δD and Cl−, determine their seasonal variations and controlling factors to be used as baseline data in hydrological and climatological studies. The δ18O–δD relationship of rainfall gives a regression line: δD = 7.93 δ18O + 13.26 (R2 = 0.99), which represents the Ndop Meteoric Water Line (NMWL).