Diet and habitat of unique individuals of Dinohippus mexicanus and Neohipparion eurystyle (Equidae) from the late Hemphillian (Hh3) of Guanajuato and Jalisco, central Mexico: stable isotope studies

2017 ◽  
Vol 34 (1) ◽  
pp. 38
Author(s):  
Víctor Adrián Pérez-Crespo ◽  
Oscar Carranza-Castañeda ◽  
Joaquín Arroyo-Cabrales ◽  
Pedro Morales-Puente ◽  
Edith Cienfuegos-Alvarado ◽  
...  
Keyword(s):  
Stable Isotope ◽  
C4 Plants ◽  
The Other ◽  
C3 Plants ◽  
Central Mexico ◽  
Stable Carbon ◽  
Carbon And Oxygen Isotopes ◽  
Isotope Studies ◽  
Santa Maria ◽  
Mixed Feeder

Stable carbon and oxygen isotopes were determined in molar enamel from fossil Pliocene equids from Rancho El Ocote in the San Miguel Allende basin, Guanajuato, and from Santa María, Tecolotlán basin, Jalisco. At each locality, the source was one molar from an individual Dinohippus mexicanus and one molar from an individual Neohipparion eurystyle. Results indicated that the N. eurystyle individuals from both localities had been C3/C4 mixed feeders, and had lived in open-zone vegetation (δ13C: -3.1‰ to -1.3‰; δ18O: -4.9‰ to -6.4‰). On the other hand, the D. mexicanus from Rancho El Ocote had fed upon C4 plants and lived in open zones (δ13C: -1.3‰; δ18O: -4.9‰), whereas the D. mexicanus from Santa María was a C3/C4 mixed feeder with considerable consumption of C3 plants (δ13C: -7.7‰; δ18O: -6.4‰). These results could be contrast to suggestions from previous isotopic work that D. mexicanus in Mexico predominantly fed on C4 plants and further samples analyses are warranted. This study contributes to the understanding of the Pliocene equid taxa from central Mexico and emphasizes the presence of different diets, ranging from exclusive C4 to mixed C3/C4 plants.

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.

Mechanism of anaerobic biological activated carbon process examined by using stable isotope

1996 ◽  
Vol 34 (5-6) ◽  
pp. 429-435 ◽  
Author(s):  
Toshiaki Saito ◽  
Keisuke Hanaki ◽  
Tomonori Matsuo
Keyword(s):  
Activated Carbon ◽  
Stable Isotope ◽  
Carbon Isotope ◽  
Isotope Ratio ◽  
Stable Carbon Isotope ◽  
The Other ◽  
Bulk Liquid ◽  
Stable Carbon ◽  
Biological Activated Carbon ◽  
Attached Bacteria

This research focused on the mechanism of substrate transfer in anaerobic biological activated carbon (BAC) process. There are two possible pathways of substrate supply to the attached bacteria in BAC process. One is the pathway from the bulk liquid and the other is the pathway directly from activated carbon. Stable carbon isotope was used to determine them. The isotope ratio of produced methane was between isotope ratios in bulk liquid and inside activated carbon. This means that activated carbon can supply adsorbed substances directly to the attached bacteria without releasing them into bulk liquid.

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>

Stable isotope studies in the Salitroso Lake Basin (southern Patagonia, Argentina): assessing diet of Late Holocene hunter-gatherers

2009 ◽  
Vol 19 (2) ◽  
pp. 297-308 ◽  
Author(s):  
A. Tessone ◽  
A. F. Zangrando ◽  
G. Barrientos ◽  
R. Goñi ◽  
H. Panarello ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Late Holocene ◽  
Lake Basin ◽  
Hunter Gatherers ◽  
Southern Patagonia ◽  
Isotope Studies

Effects of development on techniques for calcium stable isotope studies in children

1994 ◽  
Vol 23 (6) ◽  
pp. 357-361 ◽  
Author(s):  
Kimberly O. O'Brien ◽  
Steven A. Abrams
Keyword(s):  
Stable Isotope ◽  
Isotope Studies

Growth rate and habitat of Nautilus pompilius inferred from radioactive and stable isotope studies

Paleobiology ◽  
1981 ◽  
Vol 7 (4) ◽  
pp. 469-480 ◽  
Author(s):  
J. Kirk Cochran ◽  
Danny M. Rye ◽  
Neil H. Landman
Keyword(s):  
Growth Rate ◽  
Half Life ◽  
Activity Ratio ◽  
Sea Water ◽  
Tissue Growth ◽  
Carbon And Oxygen Isotopes ◽  
Nautilus Pompilius ◽  
Radioactive Disequilibrium ◽  
Horizontal Migration ◽  
Isotope Studies

The growth rate of Nautilus pompilius in its natural environment has been determined from radioactive disequilibrium between 210Pb (half-life 22.3 yr) and its granddaughter 210Po (half-life 138 d) in septa of two juvenile specimens. 210Pb and 210Po data from the most recently formed shell material of both specimens indicate that 210Pb from sea water is incorporated into septa during septal formation and 210Po is excluded. Therefore the 210Po/210Pb activity ratio serves as a chronometer to estimate the age of each septum and the time between formation of septa. In the specimens studied the average time between sucessive points in septal deposition is 75 d for the nine most recent septa of one specimen and 23 d for the six most recent septa of the other specimen. These different growth rates, if representative of the ontogeny of each animal, suggest that the timing of septal deposition probably is dependent on the rate of shell and tissue growth coupled with buoyancy requirements and is not a unique period for all Nautilus. The habitat and ontogeny of Nautilus may be inferred from the pattern of stable isotopes of oxygen and carbon in the septa. Both specimens show a pronounced break in δ18O from nearly uniform light values in the first seven septa to heavier values (∼1%) after the seventh septum. We interpret this break to correspond to the hatching of Nautilus. A temperature (i.e. water depth) interpretation of the δ18O data for septa after the eighth is complicated by a positive correlation between δ18O and δ13C. This may reflect horizontal migration of the animal or a kinetically controlled fractionation of carbon and oxygen isotopes during septal formation.

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