Use of stable isotopes to determine methane oxidation in landfill cover soils

Liptay, Karen; Chanton, J.; Czepiel, P.; Mosher, Byard W.

doi:10.1029/97jd02630

Cited by 169 publications

(228 citation statements)

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“…While for the microbial oxidation process isotopic fractionation factors ranging between 1.003 and 1.049 have been reported (Cabral et al, 2010;Templeton et al, 2006;Reeburgh et al, 1997), fractionation factors for gas transport are scarce and calculations of CH 4 oxidation efficiencies for landfill cover soils predominantly have assumed α trans = 1, supposing that gas transport of CH 4 is dominated by advection (Liptay et al, 1998). To our knowledge, the isotopic fractionation factor for diffusion has so far not been determined for soils, but only for a glass bead (diameter 2-3 mm) porous medium with α diff = 1.0178 ± 0.001 (De Visscher et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

“…In addition to the above-mentioned methods, studies in landfill cover soils and swamp forests determined the CH 4 oxidation efficiency by measuring the changes in the ratio of two stable CH 4 isotopologues, 13 CH 4 and 12 CH 4 (Nozhevnikova et al, 2003;Chanton et al, 2008a;De Visscher et al, 1999Happell et al, 1994;Liptay et al, 1998). The approach utilizes the fact that isotopic fractionation occurs when CH 4 is oxidized: the remaining CH 4 becomes heavier and the produced CO 2 becomes lighter (Barker and Fritz, 1981) as the light isotopologue 12 CH 4 is oxidized more readily by methanotrophic bacteria than the heavier 13 CH 4 .…”

Section: Introductionmentioning

confidence: 99%

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Improved quantification of microbial CH<sub>4</sub> oxidation efficiency in arctic wetland soils using carbon isotope fractionation

et al. 2013

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Abstract. Permafrost-affected tundra soils are significant sources of the climate-relevant trace gas methane (CH4). The observed accelerated warming of the arctic will cause deeper permafrost thawing, followed by increased carbon mineralization and CH4 formation in water-saturated tundra soils, thus creating a positive feedback to climate change. Aerobic CH4 oxidation is regarded as the key process reducing CH4 emissions from wetlands, but quantification of turnover rates has remained difficult so far. The application of carbon stable isotope fractionation enables the in situ quantification of CH4 oxidation efficiency in arctic wetland soils. The aim of the current study is to quantify CH4 oxidation efficiency in permafrost-affected tundra soils in Russia's Lena River delta based on stable isotope signatures of CH4. Therefore, depth profiles of CH4 concentrations and δ13CH4 signatures were measured and the fractionation factors for the processes of oxidation (αox) and diffusion (αdiff) were determined. Most previous studies employing stable isotope fractionation for the quantification of CH4 oxidation in soils of other habitats (such as landfill cover soils) have assumed a gas transport dominated by advection (αtrans = 1). In tundra soils, however, diffusion is the main gas transport mechanism and diffusive stable isotope fractionation should be considered alongside oxidative fractionation. For the first time, the stable isotope fractionation of CH4 diffusion through water-saturated soils was determined with an αdiff = 1.001 &pm; 0.000 (n = 3). CH4 stable isotope fractionation during diffusion through air-filled pores of the investigated polygonal tundra soils was αdiff = 1.013 &pm; 0.003 (n = 18). Furthermore, it was found that αox differs widely between sites and horizons (mean αox = 1.017 ± 0.009) and needs to be determined on a case by case basis. The impact of both fractionation factors on the quantification of CH4 oxidation was analyzed by considering both the potential diffusion rate under saturated and unsaturated conditions and potential oxidation rates. For a submerged, organic-rich soil, the data indicate a CH4 oxidation efficiency of 50% at the anaerobic–aerobic interface in the upper horizon. The improved in situ quantification of CH4 oxidation in wetlands enables a better assessment of current and potential CH4 sources and sinks in permafrost-affected ecosystems and their potential strengths in response to global warming.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Improved quantification of microbial CH<sub>4</sub> oxidation efficiency in arctic wetland soils using carbon isotope fractionation

et al. 2013

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“…flux 327 chamber technique). Several previous studies have investigated isotopic signatures of methane 328 emissions from landfills using flux chambers to capture methane fluxes from the soil and collect air 329 samples (Liptay et al, 1998;Chanton and Liptay, 2000). In order to ensure a representative area is 330 covered, many chambers need to be arranged across the site, often highlighting the large spatial 331 variability of the 13 C signature measured.…”

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confidence: 99%

Plume mapping and isotopic characterisation of anthropogenic methane sources

Zazzeri

Lowry

Fisher

et al. 2015

Atmospheric Environment

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Methane stable isotope analysis, coupled with mole fraction measurement, has been used to link isotopic signature to methane emissions from landfill sites, coal mines and gas leaks in the United Kingdom. A mobile Picarro G2301 CRDS (Cavity Ring-Down Spectroscopy) analyser was installed on a vehicle, together with an anemometer and GPS receiver, to measure atmospheric methane mole fractions and their relative location while driving at speeds up to 80 kph. In targeted areas, when the methane plume was intercepted, air samples were collected in Tedlar bags, for δ¹³C-CH4 isotopic analysis by CF-GC-IRMS (Continuous Flow Gas Chromatography-Isotopic Ratio Mass Spectroscopy). This method provides high precision isotopic values, determining δ¹³C-CH4 to ± 0.05 per mil. The bulk signature of the methane plume into the atmosphere from the whole source area was obtained by Keeling plot analysis, and a δ¹³C-CH4 signature, with the relative uncertainty, allocated to each methane source investigated. Both landfill and natural gas emissions in SE England have tightly constrained isotopic signatures. The averaged δ¹³C-CH4 for landfill sites is -58 ± 3 ‰. The δ¹³C-CH4 signature for gas leaks is also fairly constant around -36 ± 2 ‰, a value characteristic of homogenised North Sea supply. In contrast, signatures for coal mines in N. England and Wales fall in a range of -51.2 ± 0.3 ‰ to -30.9 ± 1.4 ‰, but can be tightly constrained by region. The study demonstrates that CRDSbased mobile methane measurement coupled with off-line high precision isotopic analysis of plume samples is an efficient way of characterising methane sources. It shows that isotopic measurements allow type identification, and possible location of previously unknown methane sources. In modelling studies this measurement provides an independent constraint to determine the contributions of different sources to the regional methane budget and in the verification of inventory source distribution. 6/03/2015Dear editor, Hereby we resubmit our paper "Plume mapping and isotopic characterisation of anthropogenic methane sources" for publication in Atmospheric Environment.We have appreciated the thoughtful comments of the two reviewers, and we have modified our manuscript to accommodate and answer the questions. In the response to reviewers we indicate point-by-point how we have accommodated their comments.We hope you will find this revised version acceptable for publication.With best regards, on behalf of all co-authors, Giulia ZazzeriPlease address all correspondence to: Giulia Zazzeri Giulia.Zazzeri.2011@live.rhul.ac.uk Phone Number: +447952842253 Yours sincerely, Giulia Zazzeri, PhD student. Cover LetterWe thank the referees for their positive comments. We have made changes accordingly following their suggests, and we have clarified the points that were raised in the detailed comments below. Thank you for the suggestion. We explained the global CH 4 trend and relative source contributions in a little more depth in the introduction. Fig 1: what are the 5x5 big...

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“…The nondegradable portion of landfill C (mostly lignin or inaccessible cellulose) was considered for the purposes of this analysis to be a permanent sink of C. For the landfill C fraction that decays, 50 percent by molar mass is assumed to be converted to CO 2 and 50 percent to CH 4 in anaerobic conditions (NCASI 2004). We assumed 10 percent of the landfill methane was chemically oxidized or converted by bacteria to CO 2 as it travels through the landfill soil cover (Liptay et al 1998, USEPA 2002, although recent literature suggests this estimate is low (mean of 36.5 percent for 42 studies reviewed by Chantona et al 2009). Based on national estimates (USEPA 2002), we assumed that 49 percent of CH4 landfill gas is produced at landfills with gas collection systems with 75 percent collection efficiency, suggesting an effective national capture rate of 36.75 percent.…”

Section: Disposal and Methane Emission Assumptionsmentioning

confidence: 99%

ForGATE - A Forest Sector Greenhouse Gas Assessment Tool for Maine: Calibration and Overview

Hennigar¹,

Amos‐Binks²,

Cameron³

et al. 2013

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This report describes the background calibration, inputs, and outputs of ForGATE, a forest sector greenhouse gas (GHG) accounting tool designed primarily to communicate information relevant to the evaluation of projected net GHG exchange in the context of Maine's forests, the Northeast forest sector, and alternative national or regional carbon (C) accounting guidelines. It also provides forest managers and policy makers with an easy-to-use tool for examining the relative merit (C credit revenue vs. project cost) of C offset projects and forest sector life cycle GHG accounting. GHG accounts include: 1) storage in aboveground and belowground live biomass and dead organic matter components; 2) storage in forest products in use and in landfill; 3) forest sector emissions by harvest, transport, and mills, or avoided emissions (substitution, bioenergy); as well as 4) landfill methane release and avoided emissions from methane energy capture. Different forest and forest product pools can be included in result summaries to reflect different C accounting guidelines (e.g., Climate Action Reserve, Voluntary Carbon Standard). Results can be compared for baseline and C offset project scenarios. Where possible, the marginal differences between baseline and project scenario performance indicators are calculated. All forest-level emission or storage measures are expressed in tonnes of CO 2 equivalents for comparison purposes. Finally, economic indicators such as net present value and benefit-cost ratios for C offset projects can be evaluated using alternative assumptions for the value of stumpage, C credits, and offset project costs. The user enters their own inventory of stand type area by treatment regime data for baseline and offset project scenarios and can quickly adjust many GHG accounting parameters. ForGATE is available without charge from http://www.nrs.fs.fed.us/tools/forgate/. AuthorsCHRIS HENNINGAR is a research associate with the

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Use of stable isotopes to determine methane oxidation in landfill cover soils

Cited by 169 publications

References 60 publications

Improved quantification of microbial CH<sub>4</sub> oxidation efficiency in arctic wetland soils using carbon isotope fractionation

Improved quantification of microbial CH<sub>4</sub> oxidation efficiency in arctic wetland soils using carbon isotope fractionation

Plume mapping and isotopic characterisation of anthropogenic methane sources

ForGATE - A Forest Sector Greenhouse Gas Assessment Tool for Maine: Calibration and Overview

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Use of stable isotopes to determine methane oxidation in landfill cover soils

Cited by 169 publications

References 60 publications

Improved quantification of microbial CH&lt;sub&gt;4&lt;/sub&gt; oxidation efficiency in arctic wetland soils using carbon isotope fractionation

Improved quantification of microbial CH&lt;sub&gt;4&lt;/sub&gt; oxidation efficiency in arctic wetland soils using carbon isotope fractionation

Plume mapping and isotopic characterisation of anthropogenic methane sources

ForGATE - A Forest Sector Greenhouse Gas Assessment Tool for Maine: Calibration and Overview

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Product

Resources

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Improved quantification of microbial CH<sub>4</sub> oxidation efficiency in arctic wetland soils using carbon isotope fractionation

Improved quantification of microbial CH<sub>4</sub> oxidation efficiency in arctic wetland soils using carbon isotope fractionation