Testing the use of septum‐capped vials for <sup>13</sup>C‐isotope abundance analysis of carbon dioxide

Hardie, S.M.L.; Garnett, Mark H.; Fallick, Anthony E.; Stott, Alistair W.; Rowland, A. P.; Ostle, Nicholas J.

doi:10.1002/rcm.4575

Cited by 11 publications

(5 citation statements)

References 17 publications

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“…Gas samples were injected into pre-evacuated, rubber septum sealed 12 ml tubes (Exetainer; Labco, High Wycombe, UK). In order to prevent ambient air from entering the exetainers, the gas samples were pressurised by injecting a volume of 15 ml into 12 ml tubes (Hardie et al ., 2010). The CO 2 concentrations and isotopic compositions of the gas samples were measured within 1 month after sampling on a Finnigan Delta V Advantage Mass Spectrometer with Finnigan GasBench (Thermo Fisher Scientific, Whaltham, MA, USA).…”

Section: Methodsmentioning

confidence: 99%

Summer drought alters carbon allocation to roots and root respiration in mountain grassland

et al. 2014

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Drought affects the carbon (C) source and sink activities of plant organs, with potential consequences for belowground C allocation, a key process of the terrestrial C cycle. The responses of belowground C allocation dynamics to drought are so far poorly understood.We combined experimental rain exclusion with 13C pulse labelling in a mountain meadow to analyse the effects of summer drought on the dynamics of belowground allocation of recently assimilated C and how it is partitioned among different carbohydrate pools and root respiration.Severe soil moisture deficit decreased the ecosystem C uptake and the amounts and velocity of C allocated from shoots to roots. However, the proportion of recently assimilated C translocated belowground remained unaffected by drought. Reduced root respiration, reflecting reduced C demand under drought, was increasingly sustained by C reserves, whilst recent assimilates were preferentially allocated to root storage and an enlarged pool of osmotically active compounds.Our results indicate that under drought conditions the usage of recent photosynthates is shifted from metabolic activity to osmotic adjustment and storage compounds.

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Section: Methodsmentioning

confidence: 99%

Summer drought alters carbon allocation to roots and root respiration in mountain grassland

et al. 2014

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“…The precision of these systems is limited largely by gas handling and care has to be taken in the use and storage of air in septum-capped vials. [51][52][53] Executainers have the added advantage in that they can also be used as reaction vessels for liberating CO 2 from carbonates by the addition of acid, a useful feature when, for example, alkali solutions have been used to trap CO 2 in a chamber system.…”

Section: Analysis By Mass Spectrometry or Laser Absorptionmentioning

confidence: 99%

Challenges in measuring the δ¹³C of the soil surface CO₂ efflux

Midwood

Millard

2010

Rapid Comm Mass Spectrometry

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The d 13C of the soil surface efflux of carbon dioxide (d 13 CR S ) has emerged as a powerful tool enabling investigation of a wide range of soil processes from characterising entire ecosystem respiration to detailed compound-specific isotope studies. d 13 CR S can be used to trace assimilated carbon transfer below ground and to partition the overall surface efflux into heterotrophic and autotrophic components. Despite this wide range of applications no consensus currently exists on the most appropriate method of sampling this surface efflux of CO 2 in order to measure d 13 CR S . Here we consider and compare the methods which have been used, and examine the pitfalls. We also consider a number of analysis options, isotope ratio mass spectrometry (IRMS), tuneable diode laser spectroscopy (TDLS) and cavity ring-down laser spectroscopy (CRDS Increasing levels of atmospheric carbon dioxide (CO 2 ) and predicted climate change have intensified research efforts to better understand the global carbon (C) cycle. Within terrestrial ecosystems, soils hold substantial amounts of C and through the exchange of CO 2 with the atmosphere have the ability to act as either a C source or a sink.[1] It is this balance and how it may be influenced by future climate change and/or land use change which has been the focus of considerable debate for some time.[2-5] The net exchange of CO 2 across a landscape can be measured using a specialist technique called eddy covariance.[6] However, eddy covariance measurements do not provide any detailed information on the underlying mechanisms which drive the terrestrial C cycle, namely photosynthesis and respiration. [7] For several decades now the stable carbon isotope 13 C has been used extensively to provide a better understanding of these two processes at a range of scales. At the ecosystem scale so-called isofluxes [8] can be measured by combining micrometeorological measurements with the 13 C analysis of CO 2 within and above the plant canopy. This type of measurement allows total ecosystem respiration to be measured -a combination of both plant (stem/leaf) respiration and the respiration from soil, or efflux rate. With the contribution of soil-derived CO 2 being important as this can provide information on the longterm overall net C balance of the system. Two basic processes contribute to the soil surface CO 2 efflux rate (R S ): autotrophic respiration from roots and the rhizosphere, and heterotrophic respiration from the turnover of soil organic matter (SOM).Against this background, measuring the rate at which CO 2 leaves the soil surface coupled with the measurement of its 13 C/ 12 C ratio (d 13 CR S ) has emerged as a key tool in ecophysiological research and global terrestrial C cycle studies. Isotopic analyses provide a means of distinguishing the C sources which contribute to this overall flux, allowing either the autotrophic or the heterotrophic components to be quantified. For example, d13 CR S measurements have been used to assess the speed at which assimilated C is transfe...

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“…However, after 20 hr, a notable reduction of both parameters occurred. Consequently, in cases where sampling logistics require samples to be stored for longer periods of time, we suggest other gas storage options, such as septum‐capped vials (Hardie et al., 2010) or multi‐layered foil sample bags (Boudoir et al., 2020) proving reliable conditions for long‐term sample storage. Alternatively, including separate reference samples as “external standards” with defined air of similar CO 2 concentration and isotopic composition in the aluminum sample bags presented in this study would allow for the quantification of possible fractionation or leakage effects that could arise during long‐term storage.…”

Section: Discussionmentioning

confidence: 99%

Tracing Low‐CO₂ Fluxes in Soil Incubation and ¹³C Labeling Experiments: A Simplified Gas Sampling System for Respiration and Photosynthesis Measurements

Witzgall,

Hesse,

Seguel

et al. 2023

JGR Biogeosciences

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Quantifying carbon dioxide (CO2) fluxes between soil and atmosphere is key in understanding net ecosystem C exchange and biogeochemical C cycling in plant‐soil systems. In ecosystems with low primary production and sparse vegetation, for example, dry lands or subpolar regions where C fluxes are small, measurement sensitivity is key—even so when measurements are combined with isotopic labeling. Here, we present a simplified gas sampling system developed to facilitate sampling and measurement of low soil CO2 fluxes as well as in situ 13CO2 labeling in the same setup. The capacity of the system was tested in a set of feature tests along with gas measurements of dryland soil‐biocrust systems. The system's sensitivity to capture minor changes in CO2 concentration was confirmed in respiration and photosynthesis measurements of soil‐biocrust systems, where fluxes down to 0.1 μmol CO2 m−2 s−1 were quantified. A balloon, implemented to counterbalance underpressure build‐up during gas withdrawal, mitigated 72% of pressure differences at sampling. The overall system volume was reduced to a minimum to limit contamination caused by residual air, and the design enabled one‐step flushing and evacuation of system compartments and gas sample bags, successfully ruling out cross‐contamination between samples. Ultimately, this system offers a flexible and accessible solution for CO2 measurements that can be applied not only on arid soils with low biological activity and turnover rates, but also on plant‐soil systems. The modifications enabled larger, and thereby more representative, sample volumes to be collected while limiting incubation, contamination, and pressure effects on the intact soil system.

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Testing the use of septum‐capped vials for ¹³C‐isotope abundance analysis of carbon dioxide

Cited by 11 publications

References 17 publications

Summer drought alters carbon allocation to roots and root respiration in mountain grassland

Summer drought alters carbon allocation to roots and root respiration in mountain grassland

Challenges in measuring the δ¹³C of the soil surface CO₂ efflux

Tracing Low‐CO₂ Fluxes in Soil Incubation and ¹³C Labeling Experiments: A Simplified Gas Sampling System for Respiration and Photosynthesis Measurements

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Testing the use of septum‐capped vials for 13C‐isotope abundance analysis of carbon dioxide

Cited by 11 publications

References 17 publications

Summer drought alters carbon allocation to roots and root respiration in mountain grassland

Summer drought alters carbon allocation to roots and root respiration in mountain grassland

Challenges in measuring the δ13C of the soil surface CO2 efflux

Tracing Low‐CO2 Fluxes in Soil Incubation and 13C Labeling Experiments: A Simplified Gas Sampling System for Respiration and Photosynthesis Measurements

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Testing the use of septum‐capped vials for ¹³C‐isotope abundance analysis of carbon dioxide

Challenges in measuring the δ¹³C of the soil surface CO₂ efflux

Tracing Low‐CO₂ Fluxes in Soil Incubation and ¹³C Labeling Experiments: A Simplified Gas Sampling System for Respiration and Photosynthesis Measurements