scholarly journals Stable carbon isotopic composition of biomass burning emissions – implications for estimating the contribution of C3 and C4 plants

2021 ◽  
Author(s):  
Roland Vernooij ◽  
Ulrike Dusek ◽  
Maria Elena Popa ◽  
Peng Yao ◽  
Anupam Shaikat ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Biomass Burning ◽  
Field Experiments ◽  
Combustion Products ◽  
C4 Plants ◽  
C3 Plants ◽  
Stable Carbon ◽  
Atmospheric Measurements ◽  
C3 And C4 Plants ◽  
Large Variability

Abstract. Landscape fires are a significant contributor to atmospheric burdens of greenhouse gases and aerosols. Although many studies have looked at biomass burning products and their fate in the atmosphere, estimating and tracing atmospheric pollution from landscape fires based on atmospheric measurements is challenging due to the large variability in fuel composition and burning conditions. Stable carbon isotopes in biomass burning (BB) emissions can be used to trace the contribution of C3 plants (e.g., trees or shrubs) and C4 plants (e.g. savanna grasses) to various combustion products. However, there are still many uncertainties regarding changes in isotopic composition (also known as fractionation) of the emitted carbon compared to the burnt fuel during the pyrolysis and combustion processes. To study BB isotope fractionation, we performed a series of laboratory fire experiments in which we burned pure C3 and C4 plants as well as mixtures of the two. Using isotope ratio mass spectrometry (IRMS), we measured stable carbon isotope signatures in the pre-fire fuels and post-fire residual char, as well as in the CO2, CO, CH4, organic carbon (OC), and elemental carbon (EC) emissions, which together constitute over 98 % of the post-fire carbon. Our laboratory tests indicated substantial isotopic fractionation in combustion products compared to the fuel, which varied between the measured fire products. CO2, EC and residual char were the most reliable tracers of the fuel 13C signature. CO in particular showed a distinct dependence on burning conditions; flaming emissions were enriched in 13C compared to smouldering combustion emissions. For CH4 and OC, the fractionation was opposite for C3 emissions (13C-enriched) and C4 emissions (13C-depleted). This indicates that while it is possible to distinguish between fires that were dominated by either C3 or C4 fuels using these tracers, it is more complicated to quantify their relative contribution to a mixed-fuel-fire based on the δ13C signature of emissions. Besides laboratory experiments, we sampled gases and carbonaceous aerosols from prescribed fires in the Niassa special Reserve (NSR) in Mozambique, using an unmanned aerial system (UAS)-mounted sampling set-up. We also provide a range of C3 : C4 contributions to the fuel and measured the fuel isotopic signatures. While both OC and EC were useful tracers of the C3 to C4 fuel ratio in mixed fires in the lab, we found particularly OC to be depleted compared to the calculated fuel signal in the field experiments. This suggests that either our fuel measurements were incomprehensive and underestimated the C3 : C4 ratio in the field, or that other processes caused this depletion. Although additional field measurements are needed, our results indicate that C3 vs C4 source ratio estimation is possible with most BB products, albeit with varying uncertainty ranges.

Stable carbon isotopic composition of biomass burning emissions – implications for estimating the contribution of C3 and C4 plants

2020 ◽  
Author(s):  
Ulrike Dusek ◽  
Roland Vernooij ◽  
Anupam Shaikat ◽  
Chenxi Qiu ◽  
Elena Popa ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Stable Carbon Isotope ◽  
Carbon Isotopic Composition ◽  
Combustion Process ◽  
C4 Plants ◽  
C3 Plants ◽  
Stable Carbon ◽  
C3 And C4 Plants ◽  
First Results

<p>Biomass burning on the African continent emits large amounts of CO<sub>2</sub>, CO, and aerosols. Our aim is to use measurements of the stable carbon isotope <sup>13</sup>C in organic carbon, CO and CO<sub>2</sub> in biomass burning smoke to estimate the contribution of C3 plants (trees and bushes) and C4 plants (mainly Savannah grass), which have very distinct <sup>13</sup>C/<sup>12</sup>C ratios. This is possible, if <sup>13</sup>C/<sup>12</sup>C ratios are not significantly altered by the combustion process. This assumption is investigated in a series of laboratory experiments, where C3 and C4 plants (corn and willow wood), or C3-C4 plant mixtures are burned. The laboratory results are used to interpret the results of pilot studies of smoke sampled in African savannah fires.</p><p> </p><p>First results from the laboratory studies indicate that organic carbon (OC) from combustion of willow or corn shows <sup>13</sup>C/<sup>12</sup>C ratios comparable to the burned plant material. For combustion of willow (C3), the <sup>13</sup>C/<sup>12</sup>C ratios in OC tend to be slightly higher than in the wood fuel, depending on combustion conditions. For combustion of corn <sup>13</sup>C/<sup>12</sup>C ratios of OC tend to be slightly lower than in the fuel. For mixtures of willow and corn the relationship between <sup>13</sup>C/<sup>12</sup>C ratios in the emitted organic carbon and the fuel mixture is slightly non-linear: For a 50-50% oak wood and corn mixture the <sup>13</sup>C/<sup>12</sup>C ratio in OC is closer to that of corn than that of willow. First results from pilot field studies indicate that a larger fraction of OC comes from trees and bushes, although mainly Savannah grass is burned in the investigated fires.</p>

scholarly journals Seasonal study of stable carbon and nitrogen isotopic composition in fine aerosols at a Central European rural background station

2019 ◽  
Vol 19 (6) ◽  
pp. 3463-3479 ◽  
Author(s):  
Petr Vodička ◽  
Kimitaka Kawamura ◽  
Jaroslav Schwarz ◽  
Bhagawati Kunwar ◽  
Vladimír Ždímal
Keyword(s):  
Seasonal Variation ◽  
Isotopic Composition ◽  
Ambient Temperature ◽  
Biomass Burning ◽  
Isotope Ratios ◽  
Water Soluble ◽  
Total Carbon ◽  
Stable Carbon ◽  
Δ13c Values ◽  
Rural Background

Abstract. A study of the stable carbon isotope ratios (δ13C) of total carbon (TC) and the nitrogen isotope ratios (δ15N) of total nitrogen (TN) was carried out for fine aerosol particles (PM1) and was undertaken every 2 days with a 24 h sampling period at a rural background site in Košetice (Central Europe) from 27 September 2013 to 9 August 2014 (n=146). We found a seasonal pattern for both δ13C and δ15N. The seasonal variation in δ15N was characterized by lower values (average of 13.1±4.5 ‰) in winter and higher values (25.0±1.6 ‰) in summer. Autumn and spring were transition periods when the isotopic composition gradually changed due to the changing sources and ambient temperature. The seasonal variation in δ13C was less pronounced but more depleted in 13C in summer (-27.8±0.4 ‰) as compared to winter (-26.7±0.5 ‰). A comparative analysis with water-soluble ions, organic carbon, elemental carbon, trace gases and meteorological parameters (mainly ambient temperature) has shown major associations with the isotopic compositions, which has provided greater knowledge and understanding of the corresponding processes. A comparison of δ15N with NO3-, NH4+ and organic nitrogen (OrgN) revealed that although a higher content of NO3- was associated with a decrease in the δ15N of TN, NH4+ and OrgN caused increases. The highest concentrations of nitrate, mainly represented by NH4NO3 related to the emissions from biomass burning leading to an average δ15N of TN (13.3 ‰) in winter. During spring, the percentage of NO3- in PM1 decreased. An enrichment of 15N was probably driven by the equilibrium exchange between the gas and aerosol phases (NH3(g) ↔ NH4+(p)), which is supported by the increased ambient temperature. This equilibrium was suppressed in early summer when the molar ratios of NH4+/SO42- reached 2, and the nitrate partitioning in aerosol was negligible due to the increased ambient temperature. Summertime δ15N values were among the highest, suggesting the aging of ammonium sulfate and OrgN aerosols. Such aged aerosols can be coated by organics in which 13C enrichment takes place by the photooxidation process. This result was supported by a positive correlation of δ13C with ambient temperature and ozone, as observed in the summer season. During winter, we observed an event with the lowest δ15N and highest δ13C values. The winter event occurred in prevailing southeast air masses. Although the higher δ13C values probably originated from biomass-burning particles, the lowest δ15N values were probably associated with agriculture emissions of NH3 under low-temperature conditions (< 0 ∘C).

Stable carbon isotope variation in C3 and C4 plants along the Amazon River

Nature ◽  
1991 ◽  
Vol 353 (6339) ◽  
pp. 57-59 ◽  
Author(s):  
Luiz A. Martinelli ◽  
Allan H. Devol ◽  
Reynaldo L. Victoria ◽  
Jeffrey E. Richey
Keyword(s):  
Carbon Isotope ◽  
Stable Carbon Isotope ◽  
C4 Plants ◽  
Amazon River ◽  
Stable Carbon ◽  
C3 And C4 Plants ◽  
Isotope Variation

scholarly journals Des-A-lupane in an East African lake sedimentary record as a new proxy for the stable carbon isotopic composition of C3 plants

2016 ◽  
Vol 101 ◽  
pp. 132-139 ◽  
Author(s):  
L.G.J. van Bree ◽  
W.I.C. Rijpstra ◽  
N.A. Al-Dhabi ◽  
D. Verschuren ◽  
J.S. Sinninghe Damsté ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotopic Composition ◽  
C3 Plants ◽  
Stable Carbon ◽  
East African ◽  
Sedimentary Record ◽  
Carbon Isotopic ◽  
African Lake

scholarly journals Rhizodegradation of PAHs differentially altered by C3 and C4 plants

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anithadevi Kenday Sivaram ◽  
Suresh Ramraj Subashchandrabose ◽  
Panneerselvan Logeshwaran ◽  
Robin Lockington ◽  
Ravi Naidu ◽  
...  
Keyword(s):  
Bacterial Diversity ◽  
Ribosomal Rna ◽  
Bacterial Communities ◽  
C4 Plants ◽  
C3 Plants ◽  
Good Resistance ◽  
C3 And C4 Plants ◽  
Incremental Change ◽  
Polycyclic Aromatic ◽  
Pahs Concentration

Abstract Pyrosequencing of 16S ribosomal RNA (rRNA) was employed to characterize bacterial communities colonizing the rhizosphere of plants with C3 and C4 photosynthetic pathways grown in soil contaminated with polycyclic aromatic hydrocarbons (PAHs) after 60 and 120 days. The results of this study exhibited a clear difference in bacterial diversity between the rhizosphere and non-rhizosphere samples and between the rhizospheres of the C3 and C4 plants after 120 days. In both C3 and C4 rhizospheres, an incremental change in PAHs degrading bacterial genera was observed in the 120th day samples compared to the 60th day ones. Among the PAHs degrading bacterial genera, Pseudomonas showed good resistance to PAHs in the 120th day rhizosphere of both C3 and C4 plants. Conversely, the genus Sphingomonas showed sensitivity to PAHs in the 120th day rhizosphere soils of C3 plants only. Also, a significant increase in the PAHs degrading genera was observed at 120th day in the C4 rhizosphere in comparison to the C3 rhizosphere, which was reflected in a reduced PAHs concentration measured in the soil remediated with C4 plants rather than C3 plants. These results suggest that the rhizoremediation of PAHs was primarily governed by the plant photosystems, which led to differences in root secretions that caused the variation in bacterial diversity seen in the rhizospheres. This study is the first report to demonstrate the greater effectiveness of C4 plants in enhancing the PAHs degrading bacterial community than C3 plants.

scholarly journals Seasonal study of stable carbon and nitrogen isotopic composition in fine aerosols at a Central European rural background station

2018 ◽  
Author(s):  
Petr Vodička ◽  
Kimitaka Kawamura ◽  
Jaroslav Schwarz ◽  
Bhagawati Kunwar ◽  
Vladimír Ždímal
Keyword(s):  
Seasonal Variation ◽  
Isotopic Composition ◽  
Ambient Temperature ◽  
Biomass Burning ◽  
Isotope Ratios ◽  
Water Soluble ◽  
Total Carbon ◽  
Stable Carbon ◽  
Δ13c Values ◽  
Rural Background

Abstract. Determinations of stable carbon isotope ratios (δ13C) of total carbon (TC) and nitrogen isotope ratios (δ15N) of total nitrogen (TN) were carried out for fine aerosol particles (PM1) collected on a daily basis at a rural background site in Košetice (Central Europe) between 27 September 2013 and 9 August 2014 (n = 146). We found a seasonal pattern for both δ13C and δ15N. The seasonal variation in δ15N was more pronounced, with 15N-depleted values (av. 13.1 ± 4.5 ‰) in winter and 15N-enriched values (25.0 ± 1.6 ‰) in summer. Autumn and spring are transition periods when the isotopic composition gradually changed due to different sources and the ambient temperature. The seasonal variation in δ13C was less pronounced but more depleted in 13C in summer (−27.8 ± 0.4 ‰) compared to winter (−26.7 ± 0.5 ‰). Major controls of the seasonal dependencies were found based on a comparative analysis with water-soluble ions, organic carbon, elemental carbon, trace gases and meteorological parameters (mainly ambient temperature). A comparison of δ15N with NO3−, NH4+ and organic nitrogen (OrgN) revealed that although a higher content of NO3− was associated with a decrease in δ15N values in TN, NH4+ and OrgN had the opposite influences. The highest concentrations of nitrate, mainly represented by NH4NO3, originated from the emissions from biomass burning, leading to lower δ15N values of approximately 14 ‰ in winter. During spring, the percentage of NO3− in PM1 decreased, and 15N enrichment was probably driven by equilibrium exchange between the gas and aerosol phases (NH3(g) ↔ NH4+(p)) as supported by the increased ambient temperature. This equilibrium was suppressed in early summer when the NH4+/SO42− molar ratios reached 2, and nitrate partitioning in aerosol was negligible. During summer, kinetic reactions probably were the primary processes as opposed to gas-aerosol equilibrium on a nitrogen level. However, summertime δ15N values were some of the highest observed, probably suggesting the aging of ammonium sulfate and OrgN aerosols. Such aged aerosols can be coated by organics in which 13C enrichment takes place by photooxidation process. This result was supported by the positive correlation of δ13C with temperature and ozone, as observed in the summer season. During winter, we observed an event with the lowest δ15N and highest δ13C values. The winter Event was connected with prevailing southeast winds. Although higher δ13C values probably originated from biomass burning particles, the lowest δ15N values were associated with agriculture emissions of NH3 under low temperature conditions that were below 0 °C.

scholarly journals Photosynthetic linear electron flow drives CO2 assimilation in maize leaves

2021 ◽  
Author(s):  
Ginga Shimakawa ◽  
Chikahiro Miyake
Keyword(s):  
Electron Transport ◽  
Electron Flow ◽  
Photosynthetic Electron Transport ◽  
Co2 Assimilation ◽  
C4 Plants ◽  
C3 Plants ◽  
Reaction Centre ◽  
Linear Electron ◽  
C3 And C4 Plants ◽  
Intact Leaves

Abstract Photosynthetic organisms commonly develop the strategy to keep the reaction centre chlorophyll of photosystem I, P700, oxidised for preventing the generation of reactive oxygen species in excess light conditions. In photosynthesis of C4 plants, CO2 concentration is kept at higher levels around ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) by the cooperation of the mesophyll and bundle sheath cells, which enables them to assimilate CO2 at higher rates and to survive under drought stress. However, the regulatory mechanism of photosynthetic electron transport for P700 oxidation is still poorly understood in C4 plants. Here we assessed gas exchange, chlorophyll fluorescence, electrochromic shift, and near infrared absorbance in the intact leaves of NADP-malic enzyme subtype of C4 plants maize in a comparison with the C3 plant field mustard. Instead of the alternative electron sink due to photorespiration, photosynthetic linear electron flow was strongly limited between photosystems I and II dependent on the proton gradient across the thylakoid membrane (ΔpH) in response to the suppression of CO2 assimilation in maize. The increase of ΔpH for P700 oxidation was caused by the regulation of proton conductance of chloroplast ATP synthase but not by promoting cyclic electron flow, which was supported by linear relationships among CO2 assimilation rate, linear electron flow, P700 oxidation, ΔpH, and the oxidation rate of ferredoxin. At the scale of intact leaves, the ratio of PSI to PSII was estimated almost 1:1 in both C3 and C4 plants. Overall, the photosynthetic electron transport was regulated for P700 oxidation in maize through the same strategies as in C3 plants only except for the capacity of photorespiration despite the structural and metabolic differences in photosynthesis between C3 and C4 plants.

scholarly journals Molecular distribution and compound-specific stable carbon isotopic composition of dicarboxylic acids, oxocarboxylic acids, and α-dicarbonyls in PM<sub>2.5</sub> from Beijing, China

2017 ◽  
Author(s):  
Wanyu Zhao ◽  
Kimitaka Kawamura ◽  
Siyao Yue ◽  
Lianfang Wei ◽  
Hong Ren ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Succinic Acid ◽  
Biomass Burning ◽  
Fossil Fuel ◽  
Carbon Isotopic Composition ◽  
Dicarboxylic Acids ◽  
Fossil Fuel Combustion ◽  
Stable Carbon ◽  
Carbon Isotopic ◽  
Oxocarboxylic Acids

Abstract. This study investigates the seasonal variation, molecular distribution and stable carbon isotopic composition of diacids, oxocarboxylic acids and α-dicarbonyls to better understand the sources and formation processes of fine aerosols (PM2.5) in Beijing. The concentrations of total dicarboxylic acids varied from 110 to 2580 ng m−3, whereas oxoacids (9.50–353 ng m−3) and dicarbonyls (1.50–85.9 ng m−3) were less abundant. Oxalic acid was found to be the most abundant individual species, followed by succinic acid or occasionally by terephthalic acid (tPh), a plastic burning tracer. Ambient concentrations of phthalic acid (37.9±27.3 ng m−3) and tPh (48.7±51.1 ng m−3) are larger in winter than in other seasons, illustrating that fossil fuel combustion and plastic waste incineration contribute more significantly to wintertime aerosols. The year-round mass concentration ratios of malonic acid to succinic acid (C3/C4) are relatively by comparison with those in other urban aerosols and remote marine aerosols, most of which are less than or equal to unity in Beijing; thus, the degree of photochemical formation of diacids in Beijing is insignificant. Moreover, positive correlations of some oxocarboxylic acids and α-dicarbonyls with nss-K+, a tracer for biomass burning, suggest biogenic combustion activities accounting for a large contribution of these organic acids and related precursors. The mean δ13C value of succinic acid is highest among all species with values of −17.1±3.9‰ (winter) and −17.1±2.0‰ (spring), while malonic acid is less enriched in 13C than others in autumn (−17.6±4.6‰) and summer (−18.7±4.0‰). The δ13C values of major species in the Beijing aerosols are generally lower with a wider range than those in downwind regions in the western North Pacific, which indicates that Beijing has diverse emission sources with weak photooxidation. Thus, our study demonstrates that in addition to photochemical oxidation, high abundances of diacids, oxocarboxylic acids and α-dicarbonyls in Beijing are largely associated with anthropogenic primary emissions, such as biomass burning, fossil fuel combustion, and plastic burning.

scholarly journals Compound-specific stable carbon isotopic signature of carbohydrate pyrolysis products from C3 and C4 plants

2015 ◽  
Vol 96 (3) ◽  
pp. 948-953 ◽  
Author(s):  
José A González-Pérez ◽  
Nicasio T Jiménez-Morillo ◽  
José M de la Rosa ◽  
Gonzalo Almendros ◽  
Francisco J González-Vila
Keyword(s):  
Isotopic Signature ◽  
C4 Plants ◽  
Stable Carbon ◽  
C3 And C4 Plants ◽  
Pyrolysis Products ◽  
Carbon Isotopic
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