Can C3 plants faithfully record the carbon isotopic composition of atmospheric carbon dioxide?

Paleobiology ◽  
2000 ◽  
Vol 26 (1) ◽  
pp. 137-164 ◽  
Author(s):  
Nan Crystal Arens ◽  
A. Hope Jahren ◽  
Ronald Amundson
Keyword(s):  
Carbon Dioxide ◽  
Isotopic Composition ◽  
Plant Tissue ◽  
Atmospheric Carbon Dioxide ◽  
Carbon Isotopic Composition ◽  
C3 Plants ◽  
Data Set ◽  
Carbon Isotopic ◽  
C Value ◽  
Atmospheric Carbon

Atmospheric carbon dioxide is the raw material for the biosphere. Therefore, changes in the carbon isotopic composition of the atmosphere will influence the terrestrial δ13C signals we interpret. However, reconstructing the atmospheric δ13C value in the geologic past has proven challenging. Land plants sample the isotopic composition of CO2 during photosynthesis. We use a model of carbon isotopic fractionation during C3 photosynthesis, in combination with a meta–data set (519 measurements from 176 species), to show that the δ13C value of atmospheric CO2 can be reconstructed from the isotopic composition of plant tissue. Over a range of pCO2 (198–1300 ppmv), the δ13C value of plant tissue does not vary systematically with atmospheric carbon dioxide concentration. However, environmental factors, such as water stress, can influence the δ13C value of leaf tissue. These factors explained a relatively small portion of variation in the δ13C value of plant tissue in our data set and emerged strongly only when the carbon isotopic composition of the atmosphere was held constant. Members of the Poaceae differed in average δ13C value, but we observed no other differences correlated with plant life form (herbs, trees, shrubs). In contrast, over 90% of the variation the carbon isotopic composition of plant tissue was explained by variation in the δ13C value of the atmosphere under which it was fixed. We use a subset of our data spanning a geologically reasonable range of atmospheric δ13C values (−6.4‰ to −9.6‰) and excluding C3 Poaceae to develop an equation to reconstruct the δ13C value of atmospheric CO2 based on plant values. Reconstructing the δ13C value of atmospheric CO2 in geologic time will facilitate chemostratigraphic correlation in terrestrial sediments, calibrate pCO2 reconstructions based on soil carbonates offer a window into the physiology of ancient plants.

scholarly journals On Correcting 14C Ages of Gastropod Shell Carbonate for Fractionation

Radiocarbon ◽  
2002 ◽  
Vol 44 (3) ◽  
pp. 755-760 ◽  
Author(s):  
Jeffrey S Pigati
Keyword(s):  
Isotopic Composition ◽  
Carbon Isotopic Composition ◽  
Iterative Approach ◽  
Shell Formation ◽  
Gastropod Shell ◽  
Carbon Isotopic ◽  
Soil Carbonate ◽  
Shell Carbonate ◽  
Atmospheric Carbon

Correcting the 14C age of a sample for fractionation is straightforward if the measured carbon was derived entirely from the atmosphere, either directly or through chemical and/or biological reactions that originated with atmospheric carbon. This correction is complicated in the case of gastropods that incorporate carbon from limestone or secondary carbonate (e.g. soil carbonate) during shell formation. The carbon isotopic composition of such gastropod shells is determined by fractionation, as well as mixing of carbon from sources with different isotopic values. Only the component of shell carbonate derived from atmospheric carbon should be corrected for fractionation. In this paper, the author derives a new expression for correcting the measured 14C activity of gastropod shells for fractionation, and describe an iterative approach that allows the corrected 14C activity and the fraction of shell carbonate derived from atmospheric carbon to be determined simultaneously.

An applied mineralogical investigation of concrete degradation in a major concrete road bridge

1990 ◽  
Vol 54 (377) ◽  
pp. 637-644 ◽  
Author(s):  
G. Macleod ◽  
A. J. Hall ◽  
A. E. Fallick
Keyword(s):  
Carbon Dioxide ◽  
Cement Paste ◽  
Atmospheric Carbon Dioxide ◽  
Meteoric Water ◽  
Isotope Analysis ◽  
Isotopic Fractionation ◽  
Physical Growth ◽  
Carbon Isotopic ◽  
Mineralogical Investigation ◽  
Atmospheric Carbon

AbstractA core of concrete taken from a major road bridge in the Strathclyde Region, Scotland, has been subjected to an applied mineralogical investigation, which involved stable isotope analysis, petrography, X-ray diffraction and scanning electron microscopy.The structure is actively undergoing severe degradation due to mineral growth which is related to chemical reactions between the concrete and pore fluid. The physical growth of minerals causes disfigurement and structural weakening.Pyrite and pyrrhotine hosted by dolerite aggregate appear to have been oxidized, providing sulphate for the deposition of ettringite and minor gypsum, in spheroidal cavities within the cement paste. The rainwater which passes through the structure mobilising sulphate from original gypsum in the paste and oxidizing the iron sulphides is also involved in the further leaching of elements from the cement paste and in the deposition of calcite. The isotopic values of calcites forming a crust on the concrete and a stalactite under the bridge are similar with δ13C= −19‰ PDB and δ18‰= +16‰ SMOW. We suggest that atmospheric carbon dioxide was the carbon source. The carbon isotopic fractionation of −12‰ from atmospheric carbon dioxide of δ13C= −7‰, (O'Neil and Barnes, 1971) can best be explained as due to a kinetic fractionation related to the hyper-basicity of the pore water. The equilibrium formation temperature of about 45°C calculated from the oxygen isotope values and assuming a δ18O value of meteoric water of −8‰ SMOW, is considered unreasonable. The exceptionally low δ18O values are attributed mainly to reaction kinetics and the calcite inheriting its oxygen, two-thirds from atmospheric carbon dioxide and one third from the meteoric formation water (O'Neil and Barnes, 1971). A δ18O value of atmospheric carbon dioxide of +41‰ SMOW and a δ18O value of meteoric water of −8‰ SMOW, lead to a calculated δ18O value for the calcites of +10‰ SMOW. The calcites analysed have a value of +16‰ and this may be due to partial re-equilibration towards a calculated value of +21‰ for calcite in equilibrium with the meteoric water at 20°C.

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 A high resolution record of atmospheric carbon dioxide and its stable carbon isotopic composition from the penultimate glacial maximum to the glacial inception

2013 ◽  
Vol 9 (2) ◽  
pp. 2015-2057 ◽  
Author(s):  
R. Schneider ◽  
J. Schmitt ◽  
P. Köhler ◽  
F. Joos ◽  
H. Fischer
Keyword(s):  
Carbon Cycle ◽  
Isotopic Composition ◽  
Atmospheric Carbon Dioxide ◽  
Stable Carbon Isotope ◽  
Carbon Isotopic Composition ◽  
Ice Cores ◽  
Glacial Maximum ◽  
Stable Carbon ◽  
Isotopic Data ◽  
Carbon Isotopic

Abstract. The reconstruction of the stable carbon isotope evolution in atmospheric CO2 (δ13Catm), as archived in Antarctic ice cores, bears the potential to disentangle the contributions of the different carbon cycle fluxes causing past CO2 variations. Here we present a highly resolved record of δ13Catm before, during and after the Marine Isotope Stage 5.5 (155 000 to 105 000 yr BP). The record was derived with a well established sublimation method using ice from the EPICA Dome C (EDC) and the Talos Dome ice cores in East Antarctica. We find an 0.4‰ offset between the mean δ13Catm level in the Penultimate (~140 000 yr BP) and Last Glacial Maximum (~22 000 yr BP), which can be explained by either (i) changes in the isotopic composition or (ii) intensity of the carbon input fluxes to the combined ocean/atmosphere carbon reservoir or (iii) by long-term peat buildup. Our isotopic data suggest that the carbon cycle evolution along Termination II and the subsequent interglacial was controlled by essentially the same processes as during the last 24 000 yr, but with different phasing and magnitudes. Furthermore, a 5000 yr lag in the CO2 decline relative to EDC temperatures is confirmed during the glacial inception at the end of MIS 5.5 (120 000 yr BP). Based on our isotopic data this lag can be explained by terrestrial carbon release and carbonate compensation.

scholarly journals The Effect of Fossil Fuel and Biogenic CO2 on the 13C and 14C Content of Atmospheric Carbon Dioxide

Radiocarbon ◽  
1980 ◽  
Vol 22 (2) ◽  
pp. 392-397 ◽  
Author(s):  
W G Mook
Keyword(s):  
Carbon Dioxide ◽  
Atmospheric Carbon Dioxide ◽  
Fossil Fuel ◽  
Clean Air ◽  
C Value ◽  
Atmospheric Carbon

The normalization of a measured δ14C value of atmospheric CO2 to a δ13C value of − 25‰ does not take into account the presence of fossil fuel and biogenic CO2. In this paper, we try to assess these contaminations as well as the proper 14C content of “clean air”.

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