AMS measurement of samples smaller than 300μg at center for applied isotope studies, University of Georgia

Cherkinsky, Alexander; Prasad, Ganesh; Dvoracek, Doug

doi:10.1016/j.nimb.2012.09.030

Cited by 19 publications

(11 citation statements)

References 9 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For PLFA concentrations and δ 13 C analyses, 30–40 g of tailings sediment was extracted by the modified Bligh and Dyer method 28 using 2:1 methanol/DCM. Large extractions (2.6–2.8 kg) were used for Δ 14 C PLFA analyses (sites TP1, TP2, and TP4) in order to obtain a sufficient mass of carbon (i.e., >∼50 μg) required for accurate measurements . Samples were filtered and phase separated, and the organic fraction was subsequently separated into three fractions (DCM, acetone, methanol) by gravity column chromatography using precombusted (450 °C for 8 h) fully activated silica gel (70–230 mesh, Silicycle).…”

Section: Materials and Methodsmentioning

confidence: 99%

Direct Evaluation of in Situ Biodegradation in Athabasca Oil Sands Tailings Ponds Using Natural Abundance Radiocarbon

Ahad¹,

Pakdel²

2013

Environ. Sci. Technol.

View full text Add to dashboard Cite

Compound-specific stable (δ(13)C) and radiocarbon (Δ(14)C) isotopes of phospholipid fatty acids (PLFAs) were used to evaluate carbon sources utilized by the active microbial populations in surface sediments from Athabasca oil sands tailings ponds. Algal-specific PLFAs were absent at three of the four sites investigated, and δ(13)CPLFA values were generally within ~3‰ of that reported for oil sands bitumen (~-30‰), suggesting that the microbial communities growing on petroleum constituents were dominated by aerobic heterotrophs. Δ(14)CPLFA values ranged from -906 to -586‰ and pointed to significant uptake of fossil carbon, particularly in PLFAs (e.g., cy17:0 and cy19:0) often associated with petroleum hydrocarbon degrading bacteria. The comparatively heavier Δ(14)C values found in other, less specific PLFAs (e.g., 16:0) indicated the preferential uptake of younger organic matter by the general microbial population. Since the main carbon pools in tailings sediment were essentially "radiocarbon dead" (i.e., Δ(14)C ~ -1000‰), the principal source for this relatively modern carbon is considered to be the Athabasca River, which provides the bulk of the water used in the bitumen extraction process. The preferential utilization of the minor amount of younger and presumably more labile material present in systems otherwise dominated by petroleum carbon has important implications for remediation strategies, since it implies that organic contaminants may persist long after reclamation has begun. Alternatively, this young organic matter could play a vital and necessary role in supporting the microbial utilization of fossil carbon via cometabolism or priming processes.

show abstract

Section: Materials and Methodsmentioning

confidence: 99%

Direct Evaluation of in Situ Biodegradation in Athabasca Oil Sands Tailings Ponds Using Natural Abundance Radiocarbon

Ahad¹,

Pakdel²

2013

Environ. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Depending on the wood's density, this equates to a sample approximately 3 ×3 ×3 mm in size. Techniques tailored to small sample processing may require only 0.01 mg of carbon, or about 0.1 mg of dry wood (Cherkinsky et al 2013). The “destructive” perception of radiocarbon dating should therefore be softened in light of contemporary advances in the method.…”

Section: Notesmentioning

confidence: 99%

Radiocarbon Dating of Technological Transitions: The Late Holocene Shift From Atlatl to Bow in Northwestern Subarctic Canada

Grund

Huzurbazar

2017

Am. Antiq.

View full text Add to dashboard Cite

Precolumbian archaeologists traditionally focus on periods of stability rather than change when constructing regional cultural chronologies. However, the advent of large databases of radiocarbon dates and the proliferation of open-source software environments such as R now allow archaeologists to understand technological transitions with greater chronological precision than has been historically possible. In this study, we employ Monte Carlo procedures, Bayes’ Theorem, the R package Bchron, and IntCal13 to address three chronological topics. We calculate the minimum number of dates required on atlatl and bow technologies to robustly date this late Holocene transition in Subarctic northwestern Canada, analyze previously published dates on organic projectile diagnostics to determine whether bows and atlatls overlapped for an observable amount of time, and estimate the years of calendric time that they overlapped. Results indicate that minimum sample sizes of 29 atlatl and 19 bow dates are required to characterize this particular transition in our study area. Actual radiocarbon dates show that bow and atlatl technologies temporally co-occurred within this region for 174 ± 135 (1σ) actual calendar years. Quantitative analyses such as these open the door to testing hypotheses that explain why and how technological transitions occur within and between (pre)historic groups.

show abstract

“…The 14 C data are corrected for the blank of 0.195 ±0.06 pMC, and data within 2σ of this value were reported as <0.195 pMC. The uncertainty of the blank was estimated based on the long-term reproducibility of ±30% reported for geologic graphite, coal, and calcite blanks in Cherkinsky et al (2013), which reflects the reproducibilities of both the background and the measurement.…”

Section: Resultsmentioning

confidence: 99%

Field Degassing as a New Sampling Method for¹⁴C Analyses in Old Groundwater

et al. 2017

View full text Add to dashboard Cite

ABSTRACT. Radiocarbon ( 14 C) activity in groundwater can be used to determine subsurface residence time up to ∼40 kyr, providing crucial information on dynamic properties of groundwater and on paleoclimate. However, commonly applied sampling methods for dissolved inorganic carbon (DIC-14 C) are prone to low level of modern atmospheric contamination, resulting in underestimation of groundwater ages that cluster around 30-40 kyr. We extract CO 2 gas from groundwater using a device originally developed for studies of noble gas radionuclides. Carbon is collected in the gas phase, eliminating the possibility of fostering microbial activities and aqueous chemical reactions during sample storage. This method collects C except where mixing sources of young groundwater is suspected. These field data serve as confirmations for the reliability of the newly presented sample collection and CO 2 -14 C method, and for the outstanding roles of radiokrypton isotopes in characterizing old groundwater.

show abstract

AMS measurement of samples smaller than 300μg at center for applied isotope studies, University of Georgia

Cited by 19 publications

References 9 publications

Direct Evaluation of in Situ Biodegradation in Athabasca Oil Sands Tailings Ponds Using Natural Abundance Radiocarbon

Direct Evaluation of in Situ Biodegradation in Athabasca Oil Sands Tailings Ponds Using Natural Abundance Radiocarbon

Radiocarbon Dating of Technological Transitions: The Late Holocene Shift From Atlatl to Bow in Northwestern Subarctic Canada

Field Degassing as a New Sampling Method for¹⁴C Analyses in Old Groundwater

Contact Info

Product

Resources

About

AMS measurement of samples smaller than 300μg at center for applied isotope studies, University of Georgia

Cited by 19 publications

References 9 publications

Direct Evaluation of in Situ Biodegradation in Athabasca Oil Sands Tailings Ponds Using Natural Abundance Radiocarbon

Direct Evaluation of in Situ Biodegradation in Athabasca Oil Sands Tailings Ponds Using Natural Abundance Radiocarbon

Radiocarbon Dating of Technological Transitions: The Late Holocene Shift From Atlatl to Bow in Northwestern Subarctic Canada

Field Degassing as a New Sampling Method for14C Analyses in Old Groundwater

Contact Info

Product

Resources

About

Field Degassing as a New Sampling Method for¹⁴C Analyses in Old Groundwater