@article {2922,
	title = {RADIOCARBON IN DISSOLVED ORGANIC CARBON BY UV OXIDATION: PROCEDURES AND BLANK CHARACTERIZATION AT NOSAMSABSTRACT},
	journal = {Radiocarbon},
	volume = {63},
	year = {2021},
	month = {Jan-02-2021},
	pages = {357 - 374},
	abstract = {This study describes a procedural blank assessment of the ultraviolet photochemical oxidation (UV oxidation) method that is used to measure carbon isotopes of dissolved organic carbon (DOC) at the National Ocean Sciences Accelerator Mass Spectrometry Facility (NOSAMS). A retrospective compilation of Fm and δ 13 C results for secondary standards (OX-II, glycine) between 2009 and 2018 indicated that a revised blank correction was required to bring results in line with accepted values. The application of a best-fit mass-balance correction yielded a procedural blank of 22.0 {\textpm} 6.0 μg C with Fm of 0.30 {\textpm} 0.20 and δ 13 C of-32.0 {\textpm} 3.0{\textperthousand} for this period, which was notably higher and more variable than previously reported. Changes to the procedure, specifically elimination of higher organic carbon reagents and improved sample and reactor handling, reduced the blank to 11.0 {\textpm} 2.75 μg C, with Fm of 0.14 {\textpm} 0.10 and δ 13 C of-31.0 {\textpm} 5.5{\textperthousand}. A thorough determination of the entire sample processing blank is required to ensure accurate isotopic compositions of seawater DOC using the UV oxidation method. Additional efforts are needed to further reduce the procedural blank so that smaller DOC samples can be analyzed, and to increase sample throughput.},
	keywords = {blank, dissolved organic carbon, radiocarbon, UV oxidation},
	issn = {0033-8222},
	doi = {10.1017/RDC.2020.102},
	url = {https://www.cambridge.org/core/journals/radiocarbon/article/abs/radiocarbon-in-dissolved-organic-carbon-by-uv-oxidation-procedures-and-blank-characterization-at-nosams/AA39A2C74772934B44D9BF81C2DF723C},
	author = {Xu, Li and Roberts, Mark L and Elder, Kathryn L and Kurz, Mark D and McNichol, Ann P and Reddy, Christopher M and Ward, Collin P and Hanke, Ulrich M}
}
@article {2613,
	title = {Dimensions of Radiocarbon Variability within Sedimentary Organic MatterABSTRACT},
	journal = {Radiocarbon},
	volume = {60},
	year = {2018},
	month = {Jan-06-2018},
	pages = {775 - 790},
	abstract = {Organic carbon (OC) radiocarbon (14C) signatures in marine surface sediments are highly variable and the
causes of this heterogeneity remain ambiguous. Here, we present results from a detailed 14C-based investigation of an Arabian Sea sediment, including measurements on organic matter (OM) in bulk sediment, specific grain size fractions, and OC decomposition products from ramped-pyrolysis-oxidation (RPO). Our results show that 14C ages of OM increase with increasing grain size, suggesting that grain size is an important factor controlling the 14C heterogeneity in marine sediments. Analysis of RPO decomposition products from different grain size fractions reveals an overall increase in age of corresponding thermal fractions from finer to coarser fractions. We suggest that hydrodynamic properties of sediment grains exert the important control on the 14C age distribution of OM among grain size fractions. We propose a conceptual model to account for this dimensionality in 14C variability that invokes two predominant modes of OM preservation within different grain size fractions of Arabian Sea sediment: finer (<63 μm) fractions are influenced by OM-mineral grain aggregation processes, giving rise to relatively uniform 14C ages, whereas OM preserved in coarser (>63 μm) fractions includes materials encapsulated within microfossils and/or entrained fossil (14C-depleted) OC hosted in detrital mineral grains. Our findings highlight the value of RPO for assessment of 14C age variability in sedimentary OC, and for assessing mechanisms of OM preservation in aquatic sediments.},
	keywords = {arabian sea, grain size, hydrodynamic processes, organicmatter, radiocarbon, ramped pyrolysis-oxidation},
	issn = {0033-8222},
	doi = {10.1017/RDC.2018.22},
	url = {https://www.cambridge.org/core/journals/radiocarbon/article/dimensions-of-radiocarbon-variability-within-sedimentary-organic-matter/A81022494F34D8C3B88D39A43112BB08},
	author = {Bao, Rui and McNichol, Ann P and McIntyre, Cameron P and Xu, Li and Eglinton, Timothy I}
}
