Fossil carbon sources of atmospheric methane

WILLIAM M. SACKETT; TIMOTHY R. BARBER

doi:10.1038/334201b0

The Use of Radiocarbon Measurements in Atmospheric Studies

Radiocarbon ◽

10.1017/s0033822200039941 ◽

1990 ◽

Vol 32 (1) ◽

pp. 37-58 ◽

Cited By ~ 143

Author(s):

M R Manning ◽

D C Lowe ◽

W H Melhuish ◽

R J Sparks ◽

Gavin Wallace ◽

...

Keyword(s):

Nuclear Power ◽

Circulation Model ◽

Current Data ◽

Atmospheric Methane ◽

Global Circulation Model ◽

Fossil Carbon ◽

Global Circulation ◽

Methane Source ◽

Clean Air ◽

Source Current

14C measured in trace gases in clean air helps to determine the sources of such gases, their long-range transport in the atmosphere, and their exchange with other carbon cycle reservoirs. In order to separate sources, transport and exchange, it is necessary to interpret measurements using models of these processes. We present atmospheric 14CO2 measurements made in New Zealand since 1954 and at various Pacific Ocean sites for shorter periods. We analyze these for latitudinal and seasonal variation, the latter being consistent with a seasonally varying exchange rate between the stratosphere and troposphere. The observed seasonal cycle does not agree with that predicted by a zonally averaged global circulation model. We discuss recent accelerator mass spectrometry measurements of atmospheric 14CH4 and the problems involved in determining the fossil fuel methane source. Current data imply a fossil carbon contribution of ca 25%, and the major sources of uncertainty in this number are the uncertainty in the nuclear power source of 14CH4, and in the measured value for δ14C in atmospheric methane.

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Absolute Dating of Early Iron Objects from the Ancient Orient: Radiocarbon Dating of Luristan Iron Mask Swords

Radiocarbon ◽

10.1017/rdc.2019.13 ◽

2019 ◽

Vol 61 (5) ◽

pp. 1229-1238

Author(s):

C Matthias Hüls ◽

Ingo Petri ◽

Helmut Föll

Keyword(s):

Radiocarbon Dating ◽

Carbon Sources ◽

Iron Production ◽

Museum Collections ◽

Fossil Carbon ◽

Slag Inclusions ◽

Metallurgical Analysis ◽

Absolute Dating ◽

Production Period ◽

Two Sides

ABSTRACTLuristan Iron Mask Swords have been recovered mostly from illegal diggings in the 1920s. The about 90 known objects are characterized by a disk-shaped pommel on the top of the handle with two mounted bearded heads on two sides. According to the similarity in form and radiocarbon (14C) measurements on two swords from museum collections, an overall short production period was assumed around 1000 BC (Moorey 1991; Rehder 1991). Here we present the results of metallurgical analysis and 14C measurements for three newly acquired Luristan swords, which were donated to the Royal Museums of Art & History, Brussels. Metallurgical analysis indicates an iron production via the bloomary furnace technique. Analyzed samples show large slag inclusions (Fayalite, Wüstite, glass) within a mostly ferritic and pearlitic iron. The carbon contents varied between 0.2 wt% to around 0.8 wt%). 14C measurements on thermally extracted carbon give 14C ages between 2800 BP–3360 BP (calibrated ∼1745 BC–900 BC). The reliability of the 14C measurements are discussed with respect to external (contamination during handling) and intrinsic contamination (e.g. fossil carbon sources during manufacture).

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Evaluation of Soil 14C Data for Estimating Inert Organic Matter in the Rothc Model

Radiocarbon ◽

10.1017/s0033822200042934 ◽

2007 ◽

Vol 49 (2) ◽

pp. 1079-1091 ◽

Cited By ~ 11

Author(s):

Janet Rethemeyer ◽

Pieter M Grootes ◽

Sonja Brodowski ◽

Bernard Ludwig

Keyword(s):

Organic Matter ◽

Organic Carbon ◽

Soil Organic Carbon ◽

Fossil Fuels ◽

Crop Yields ◽

Carbon Sources ◽

Specific Marker ◽

Fossil Carbon ◽

Rothc Model ◽

Similar Good

Changes in soil organic carbon stocks were simulated with the Rothamsted carbon (RothC) model. We evaluated the calculation of a major input variable, the amount of inert organic matter (IOM), using measurable data. Three different approaches for quantifying IOM were applied to soils with mainly recent organic matter and with carbon contribution from fossil fuels: 1) IOM estimation via total soil organic carbon (SOC); 2) through bulk soil radiocarbon and a mass balance; and 3) by quantifying the portion of black carbon via a specific marker. The results were highly variable in the soil containing lignite-derived carbon and ranged from 8% to 52% inert carbon of total SOC, while nearly similar amounts of 5% to 8% were determined in the soil with mainly recent organic matter. We simulated carbon dynamics in both soils using the 3 approaches for quantifying IOM in combination with carbon inputs derived from measured crop yields. In the soil with recent organic matter, all approaches gave a nearly similar good agreement between measured and modeled data, while in the soil with a fossil carbon admixture, only the 14C approach was successful in matching the measured data. Although 14C was useful for initializing RothC, care should be taken when interpreting SOC dynamics in soils containing carbon from fossil fuels, since these reflect the contribution from both natural and anthropogenic carbon sources.

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Shifts in 14C Patterns of Soil Profiles Due to Bomb Carbon, Including Effects of Morphogenetic and Turbation Processes

Radiocarbon ◽

10.1017/s0033822200012224 ◽

1989 ◽

Vol 31 (03) ◽

pp. 627-636 ◽

Cited By ~ 24

Author(s):

Hans-Wilhelm Scharpenseel ◽

Peter Becker-Heidmann

Keyword(s):

Carbon Sources ◽

Carbon Equivalent ◽

Soil Profiles ◽

Alkaline Soils ◽

Forest Clearing ◽

Fossil Carbon ◽

Soil Forming Processes ◽

The Impact ◽

Soil Rejuvenation ◽

Animal Transport

Principles contributing to changes and the final balance of rejuvenation in 14C dates of soil profiles are identified. The annual addition to the atmosphere of ca 5.5·1012kg of dead carbon from fossil carbon sources and 1.5·1012kg of older carbon from forest clearing make soil appear older. Bomb carbon and annual recycling of most of the 115·1012kg of terrestrial organic carbon, equivalent to the annual photosynthetic turnover of carbon, rejuvenates soil dates. This also applies to root growth, animal transport, and in acid or alkaline soils, to humus percolation. All available 14C dates of soil profiles were evaluated for the impact of bomb carbon. We also studied the effects of morphogenetic soil-forming processes, such as turbations, on soil rejuvenation. Bioturbation, as a general principle of soil dynamics, requires more differential treatment due to modern and bomb carbon that constitutes body carbon of earthworms as well as steadily increasing 14C age with depth in all Mollisols.

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Estimating contributions from biomass burning and fossil fuel combustion by means of radiocarbon analysis of carbonaceous aerosols: application to the Valley of Chamonix

10.5194/acp-2016-351 ◽

2016 ◽

Cited By ~ 1

Author(s):

Lise Bonvalot ◽

Thibaut Tuna ◽

Yoann Fagault ◽

Jean-Luc Jaffrezo ◽

Véronique Jacob ◽

...

Keyword(s):

Biomass Burning ◽

Road Traffic ◽

Carbon Sources ◽

Ion Source ◽

Traffic Emissions ◽

Total Carbon ◽

Geochemical Data ◽

Biogenic Emissions ◽

Carbonaceous Aerosols ◽

Fossil Carbon

Abstract. Atmospheric particulate matter (PM) affects the climate in various ways and has a negative impact on human health. In populated mountain valleys from Alpine regions, emissions from road traffic contribute to carbonaceous aerosols, but residential wood burning can be another source of PM during the winter. We determine the contribution of fossil and non-fossil carbon sources by measuring radiocarbon in aerosols using the recently installed AixMICADAS facility. The accelerator mass spectrometer is coupled to an elemental analyzer (EA) by means of a gas interface system directly connected to the gas ion source. This system provides rapid and accurate radiocarbon measurements for small samples (10–100 µgC) with minimal preparation from the aerosol filters. We show how the contamination induced by the EA protocol can be quantified and corrected for. Several standards and synthetic samples are then used to demonstrate the precision and accuracy of aerosol measurements over the full range of expected 14C/12C ratios ranging from modern carbon to fossil carbon depleted in 14C. Aerosols sampled in Chamonix and Passy (Arve Valley, French Alps) from November 2013 to August 2014 are analyzed for both radiocarbon (124 analyses in total) and levoglucosan, which is commonly used as a specific tracer for biomass burning. NOx concentration, which is expected to be associated with traffic emissions, is also monitored. Based on 14C measurements, we can show that the relative fraction of non-fossil carbon is significantly higher in winter than in summer. In winter, non-fossil carbon represents about 85 % of total carbon, while in summer this proportion is still 75 % considering all samples. The largest total carbon and levoglucosan concentrations are observed for winter aerosols with values up to 50 and 8 µg m−3, respectively. These levels are higher than those observed in many European cities, but are close to those for other polluted Alpine valleys. The non-fossil carbon concentrations are strongly correlated with the levoglucosan concentrations in winter samples, suggesting that almost all of the non-fossil carbon originates from wood combustion used for heating during winter. For summer samples, the joint use of 14C and levoglucosan measurements leads to a new model to quantify separately the contributions of biomass burning and biogenic emissions in the non-fossil fraction. The comparison of the biogenic fraction with polyols (a proxy for primary soil biogenic emissions) and with the temperature suggests a major influence of the secondary biogenic aerosols. Significant correlations are found between the NOx concentration and the fossil carbon concentration for all seasons and sites, confirming the relation between road traffic emissions and fossil carbon. Overall this dual approach combining radiocarbon and levoglucosan analyses strengthens the conclusion concerning the impact of biomass burning. Combining these geochemical data both serves to detect and quantify additional carbon sources. The Arve Valley provides a first illustration of this model to aerosols.

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Genomic and Physiological Properties of a Facultative Methane-Oxidizing Bacterial Strain of Methylocystis sp. from a Wetland

Microorganisms ◽

10.3390/microorganisms8111719 ◽

2020 ◽

Vol 8 (11) ◽

pp. 1719

Author(s):

Gi-Yong Jung ◽

Sung-Keun Rhee ◽

Young-Soo Han ◽

So-Jeong Kim

Keyword(s):

Methane Oxidation ◽

Carbon Sources ◽

Heavy Metal Resistance ◽

Metal Resistance ◽

Phylogenomic Analysis ◽

Atmospheric Methane ◽

Methane Oxidizing Bacteria ◽

Metabolic Versatility ◽

Physiological Properties ◽

Ph Range

Methane-oxidizing bacteria are crucial players in controlling methane emissions. This study aimed to isolate and characterize a novel wetland methanotroph to reveal its role in the wetland environment based on genomic information. Based on phylogenomic analysis, the isolated strain, designated as B8, is a novel species in the genus Methylocystis. Strain B8 grew in a temperature range of 15 °C to 37 °C (optimum 30–35 °C) and a pH range of 6.5 to 10 (optimum 8.5–9). Methane, methanol, and acetate were used as carbon sources. Hydrogen was produced under oxygen-limited conditions. The assembled genome comprised of 3.39 Mbp and 59.9 mol% G + C content. The genome contained two types of particulate methane monooxygenases (pMMO) for low-affinity methane oxidation (pMMO1) and high-affinity methane oxidation (pMMO2). It was revealed that strain B8 might survive atmospheric methane concentration. Furthermore, the genome had various genes for hydrogenase, nitrogen fixation, polyhydroxybutyrate synthesis, and heavy metal resistance. This metabolic versatility of strain B8 might enable its survival in wetland environments.

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Old carbon contributes to aquatic emissions of carbon dioxide in the Amazon

Biogeosciences ◽

10.5194/bg-11-3635-2014 ◽

2014 ◽

Vol 11 (13) ◽

pp. 3635-3645 ◽

Cited By ~ 11

Author(s):

L. E. Vihermaa ◽

S. Waldron ◽

M. H. Garnett ◽

J. Newton

Keyword(s):

Amazon Basin ◽

Carbon Sources ◽

Co2 Efflux ◽

Small Stream ◽

Fossil Carbon ◽

Technical Developments ◽

Small Streams ◽

C Cycle ◽

14C Age ◽

Carbon Transfer

Abstract. Knowing the rate at which carbon is cycled is crucial to understanding the dynamics of carbon transfer pathways. Recent technical developments now support measurement of the 14C age of evaded CO2 from fluvial systems, which provides an important "fingerprint" of the source of C. Here we report the first direct measurements of the 14C age of effluxed CO2 from two small streams and two rivers within the western Amazonian Basin. The rate of degassing and hydrochemical controls on degassing are also considered. We observe that CO2 efflux from all systems except for the seasonal small stream was 14C-depleted relative to the contemporary atmosphere, indicating a contribution from "old" carbon fixed before ~ 1955 AD. Further, "old" CO2 was effluxed from the perennial stream in the rainforest; this was unexpected as here connectivity with the contemporary C cycle is likely greatest. The effluxed gas represents all sources of CO2 in the aquatic system and thus we used end-member analysis to identify the relative inputs of fossil, modern and intermediately aged C. The most likely solutions indicated a contribution from fossil carbon sources of between 3 and 9% which we interpret as being derived from carbonate weathering. This is significant as the currently observed intensification of weather has the potential to increase the future release of old carbon, which can be subsequently degassed to the atmosphere, and so renders older, slower C cycles faster. Thus 14C fingerprinting of evaded CO2 provides understanding which is essential to more accurately model the carbon cycle in the Amazon Basin.

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Carbon-14 in Methane Sources and in Atmospheric Methane: The Contribution from Fossil Carbon

Science ◽

10.1126/science.245.4915.286 ◽

1989 ◽

Vol 245 (4915) ◽

pp. 286-290 ◽

Cited By ~ 205

Author(s):

M. WAHLEN ◽

N. TANAKA ◽

R. HENRY ◽

B. DECK ◽

J. ZEGLEN ◽

...

Keyword(s):

Atmospheric Methane ◽

Carbon 14 ◽

Fossil Carbon

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Accuracy Improvement of the 14C Method Applied in Biomass and Coal Co-Firing Power Stations

Processes ◽

10.3390/pr9060994 ◽

2021 ◽

Vol 9 (6) ◽

pp. 994

Author(s):

Yuxing Tang ◽

Zhongyang Luo ◽

Chunjiang Yu

Keyword(s):

Evaluation Method ◽

Growth Models ◽

Carbon Sources ◽

Reference Value ◽

Prediction Equation ◽

Test Results ◽

Biomass Fuels ◽

Domestic Literature ◽

Fossil Carbon ◽

Power Stations

The 14C method is an approach used to determine the proportion of carbon derived from biomass and fossil fuel in the co-fired flue gas. Its accuracy is mainly limited by the deviations between the applied biomass fuels’ 14C activity reference value and virtual value. To enrich the theoretical basis of the 14C method when applied to a Chinese biomass and coal co-firing power station, this study performed field sampling experiments and established a new evaluation method based on domestic literature. Unlike previous studies, this study revealed that the 14C activity of biomass far away from fossil carbon sources was 0.7–1.3 pMC lower than the local atmosphere. The 14C activity laws between tree rings and barks, specifically between eucalyptus bark and poplar bark were different, due to different growth models and different bark regeneration cycles, respectively. According to the test results and renewal conclusions, this study proposed a reasonable idea for constructing the prediction equation of referential biomass fuels’ 14C activity. Following this equation, the biomass fuels’ 14C activities of biomass direct-fired power stations at different Chinese cities were obtained.

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Estimating contributions from biomass burning, fossil fuel combustion, and biogenic carbon to carbonaceous aerosols in the Valley of Chamonix: a dual approach based on radiocarbon and levoglucosan

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-13753-2016 ◽

2016 ◽

Vol 16 (21) ◽

pp. 13753-13772 ◽

Cited By ~ 24

Author(s):

Lise Bonvalot ◽

Thibaut Tuna ◽

Yoann Fagault ◽

Jean-Luc Jaffrezo ◽

Véronique Jacob ◽

...

Keyword(s):

Biomass Burning ◽

Road Traffic ◽

Carbon Sources ◽

River Valley ◽

Traffic Emissions ◽

Total Carbon ◽

Biogenic Emissions ◽

Carbonaceous Aerosols ◽

Dual Approach ◽

Fossil Carbon

Abstract. Atmospheric particulate matter (PM) affects the climate in various ways and has a negative impact on human health. In populated mountain valleys in Alpine regions, emissions from road traffic contribute to carbonaceous aerosols, but residential wood burning can be another source of PM during winter. We determine the contribution of fossil and non-fossil carbon sources by measuring radiocarbon in aerosols using the recently installed AixMICADAS facility. The accelerator mass spectrometer is coupled to an elemental analyzer (EA) by means of a gas interface system directly connected to the gas ion source. This system provides rapid and accurate radiocarbon measurements for small samples (10–100 µgC) with minimal preparation from the aerosol filters. We show how the contamination induced by the EA protocol can be quantified and corrected for. Several standards and synthetic samples are then used to demonstrate the precision and accuracy of aerosol measurements over the full range of expected 14C ∕ 12C ratios, ranging from modern carbon to fossil carbon depleted in 14C. Aerosols sampled in Chamonix and Passy (Arve River valley, French Alps) from November 2013 to August 2014 are analyzed for both radiocarbon (124 analyses in total) and levoglucosan, which is commonly used as a specific tracer for biomass burning. NOx concentration, which is expected to be associated with traffic emissions, is also monitored. Based on 14C measurements, we can show that the relative fraction of non-fossil carbon is significantly higher in winter than in summer. In winter, non-fossil carbon represents about 85 % of total carbon, while in summer this proportion is still 75 % considering all samples. The largest total carbon and levoglucosan concentrations are observed for winter aerosols with values up to 50 and 8 µg m−3, respectively. These levels are higher than those observed in many European cities, but are close to those for other polluted Alpine valleys. The non-fossil carbon concentrations are strongly correlated with the levoglucosan concentrations in winter samples, suggesting that almost all of the non-fossil carbon originates from wood combustion used for heating during winter. For summer samples, the joint use of 14C and levoglucosan measurements leads to a new model to separately quantify the contributions of biomass burning and biogenic emissions in the non-fossil fraction. The comparison of the biogenic fraction with polyols (a proxy for primary soil biogenic emissions) and with the temperature suggests a major influence of the secondary biogenic aerosols. Significant correlations are found between the NOx concentration and the fossil carbon concentration for all seasons and sites, confirming the relation between road traffic emissions and fossil carbon. Overall, this dual approach combining radiocarbon and levoglucosan analyses strengthens the conclusion concerning the impact of biomass burning. Combining these geochemical data serves both to detect and quantify additional carbon sources. The Arve River valley provides the first illustration of aerosols of this model.

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