@article {white_refractory_2023,
	title = {Refractory Dissolved Organic Matter has Similar Chemical Characteristics but Different Radiocarbon Signatures With Depth in the Marine Water Column},
	journal = {Global Biogeochemical Cycles},
	volume = {37},
	number = {4},
	year = {2023},
	note = {_eprint: https://onlinelibrary.wiley.com/doi/pdf/10.1029/2022GB007603},
	month = {04/2023},
	pages = {e2022GB007603},
	abstract = {The >5,000-year radiocarbon age (14C-age) of much of the 630 {\textpm} 30 Pg C oceanic dissolved organic carbon (DOC) reservoir remains an enigma in the marine carbon cycle. The fact that DOC is significantly older than dissolved inorganic carbon at every depth in the ocean forms the basis of our current framing of the marine DOC cycle, where some component persists over multiple cycles of ocean mixing. As a result, 14C-depleted, aged DOC is hypothesized to be present as a uniform reservoir with a constant 14C signature and concentration throughout the water column. However, key requirements of this model, including direct observations of DOC with similar 14C signatures in the surface and deep ocean, have never been met. Despite decades of research, the distribution of Δ14C values in marine DOC remains a mystery. Here, we applied a thermal fractionation method to compare operationally defined refractory DOC (RDOC) from different depths in the North Pacific Ocean. We found that RDOC shares chemical characteristics (as recorded by OC bond strength) throughout the water column but does not share the same 14C signature. Our results support one part of the current paradigm{\textemdash}that RDOC is comprised of structurally related components throughout the ocean that form a {\textquotedblleft}background{\textquotedblright} reservoir. However, in contrast to the current paradigm, our results are consistent with a vertical concentration gradient and a vertical and inter-ocean Δ14C gradient for RDOC. The observed Δ14C gradient is compatible with the potential addition of pre-aged DOC to the upper ocean.},
	keywords = {marine dissolved organic matter, radiocarbon, ramped pyrolysis oxidation},
	issn = {1944-9224},
	doi = {10.1029/2022GB007603},
	url = {https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GB007603},
	author = {White, Margot E. and Nguyen, Tran B. and Koester, Irina and Lardie Gaylord, Mary C. and Beman, J. Michael and Smith, Kenneth L. and McNichol, Ann P. and Beaupr{\'e}, Steven R. and Aluwihare, Lihini I.}
}
@article {2942,
	title = {Soil Organic Carbon Development and Turnover in Natural and Disturbed Salt Marsh Environments},
	journal = {Geophysical Research Letters},
	volume = {48},
	year = {2021},
	month = {Apr-01-2023},
	abstract = {Salt marsh survival with sea-level rise (SLR) increasingly relies on soil organic carbon (SOC) accumulation and preservation. Using a novel combination of geochemical approaches, we characterized fine SOC (<=1 mm) supporting marsh elevation maintenance. Overlaying thermal reactivity, source (δ13C), and age (F14C) information demonstrates several processes contributing to soil development: marsh grass production, redeposition of eroded material, and microbial reworking. Redeposition of old carbon, likely from creekbanks, represented \~{}9\%{\textendash}17\% of shallow SOC (<=26 cm). Soils stored marsh grass-derived compounds with a range of reactivities that were reworked over centuries-to-millennia. Decomposition decreases SOC thermal reactivity throughout the soil column while the decades-long disturbance of ponding accelerated this shift in surface horizons. Empirically derived estimates of SOC turnover based on geochemical composition spanned a wide range (640{\textendash}9,951 years) and have the potential to inform predictions of marsh ecosystem evolution.},
	issn = {0094-8276},
	doi = {10.1029/2020GL090287},
	url = {https://onlinelibrary.wiley.com/doi/10.1029/2020GL090287},
	author = {Luk, Sheron Y. and Todd-Brown, Katherine and Eagle, Meagan and McNichol, Ann P. and Sanderman, Jonathan and Gosselin, Kelsey and Spivak, Amanda C.}
}
@article {2760,
	title = {A late Holocene subfossil Atlantic white cedar tree-ring chronology from the northeastern United States},
	journal = {Quaternary Science Reviews},
	volume = {228},
	year = {2020},
	month = {Jan-01-2020},
	pages = {106104},
	abstract = {Tree-rings provide precise annually dated climate information, but their application can be limited by the relatively short lifespan of many trees. To overcome this limitation, tree-ring records can be extended over longer time periods by connecting living trees with older {\textquotedblleft}sub-fossil{\textquotedblright} trees, which can provide information on longer timescales throughout the Holocene. These long chronologies are proxy records of past climate, provide precise chronological information for extreme events, and give insight into the range of natural climate variability prior to the instrumental period. In the densely populated northeastern United States, few tree-ring records are longer than 500 years, and there are no millennial-length tree-ring chronologies for the region. Here, we use a combination of standard dendrochronological and radiocarbon techniques, including use of the 774 CE radiocarbon excursion, to generate an absolutely dated 2500 year-long tree ring record from living, archaeological, and subfossil Atlantic white cedar (Chamaecyparis thyoides) found in the coastal northeastern United States. Our chronology demonstrates the potential to develop multi-millennial Chamaecyparis thyoides tree-ring records to address previously unanswered questions regarding late Holocene hydroclimate, extreme events, and temperature variability in New England.},
	keywords = {coastal, Geomorphology, Holocene, North America, paleoclimatology, radiogenic isotopes, Tree-rings},
	issn = {02773791},
	doi = {10.1016/j.quascirev.2019.106104},
	url = {https://linkinghub.elsevier.com/retrieve/pii/S0277379119308108},
	author = {Pearl, Jessie K. and Anchukaitis, Kevin J. and Donnelly, Jeffrey P. and Pearson, Charlotte and Pederson, Neil and Lardie Gaylord, Mary C. and McNichol, Ann P. and Cook, Edward R. and Zimmermann, George L.}
}
@article { ISI:000480669600041,
	title = {Annual radiocarbon measurements in a century-old European beech tree (Fagus sylvatica) from coastal northeastern North America},
	journal = {NUCLEAR INSTRUMENTS \& METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS},
	volume = {456},
	year = {2019},
	month = {OCT 1},
	pages = {264-270},
	abstract = {Radiocarbon (C-14) concentrations of annual tree rings from an European beech tree (Fagus sylvatica) from Woods Hole, MA, USA were analyzed at National Ocean Sciences Accelerator Mass Spectrometry facility (NOSAMS) to construct a C-14 bomb curve record from northeastern North America. The C-14 concentration rises from a pre bomb (1895-1955) average of Fraction Modern ((FC)-C-14) = 0.9764 to a peak of 1.8639 in 1964. After 1964, (FC)-C-14 gradually decreases to 1.0611 in 2014. The annual tree-ring radiocarbon content agrees with the atmospheric radiocarbon content of the Northern Hemisphere and is very similar to the radiocarbon concentration of a red oak (Quercus rubra) tree located in Bear Mountain State Park in New York, USA. Infra-annual tree-ring pairs did not produce evidence of a seasonal effect on the radiocarbon concentration, but there were few samples and more study is warranted.},
	issn = {0168-583X},
	doi = {10.1016/j.nimb.2019.03.029},
	author = {Gaylord, Mary C. Lardie and Longworth, Brett E. and Murphy, Keelan and Cobb, Caroline and McNichol, Ann P.}
}
@article { ISI:000478786500021,
	title = {CO2-dependent carbon isotope fractionation in Archaea, Part II: The marine water column},
	journal = {GEOCHIMICA ET COSMOCHIMICA ACTA},
	volume = {261},
	year = {2019},
	month = {SEP 15},
	pages = {383-395},
	abstract = {Stable carbon isotope ratios of archaeal glycerol dibiphytanyl glycerol tetraether (GDGT) lipids have been proposed as a proxy to infer past changes in the carbon isotope composition (delta C-13) of dissolved inorganic carbon (DIC). The premise for paleo-delta C-13(DIC) reconstructions from GDGTs is based on observations of relatively constant delta C-13(GDGT) values in recent depositional environments. Marine Thaumarchaeota, thought to be the dominant source of GDGTs to marine sediments, fix inorganic carbon using the 3-hydroxypropionate/4-hydroxybutyrate (3HP/4HB) pathway, which is specific to HCO3- as the substrate. Bicarbonate-dependent autotrophy has been the basis for predicting that the stable carbon isotopic composition of GDGTs (delta C-13(GDGT)) should vary in parallel with water column delta C-13(DIC) values, because HCO3- is by far the dominant fraction of DIC in modern seawater. However, this relationship has never been systematically tested. Here we examine the carbon isotopic composition of GDGTs from four water column profiles in the Southwest and Equatorial Atlantic Ocean. Values of delta C-13(GDGT) increase with depth in the water column, in contrast to the characteristic decrease in delta C-13(DIC) values. These divergent trends imply a decrease in the observed total biosynthetic isotope effect (epsilon(Ar)) with depth, i.e., the offset between delta(13)(DIC) and delta C-13(GDGT) is not constant. Instead, we find that values of epsilon(Ar) specifically correlate with oceanographic variables associated with extent of organic remineralization, decreasing as CO2 concentration increases. This observed relationship is consistent in both magnitude and direction with the results of an isotope flux-balance model for Thaumarchaeota that suggests epsilon(Ar) should be sensitive to growth rate (mu) and CO2 availability under conditions of atmospheric pCO(2) < 4 times the pre-anthropogenic Holocene level. Further tests of the sensitivity of epsilon(Ar) to u and CO2 in the modern marine environment will be essential to exploring the potential for a new, archaeal lipid-derived pCO(2) paleobarometer. (C) 2019 Elsevier Ltd. All rights reserved.},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2019.06.043},
	author = {Hurley, Sarah J. and Close, Hilary G. and Elling, Felix J. and Jasper, Claire E. and Gospodinova, Kalina and McNichol, Ann P. and Pearson, Ann}
}
@article { ISI:000461424500002,
	title = {INFLUENCE OF DIFFERENT ACID TREATMENTS ON THE RADIOCARBON CONTENT SPECTRUM OF SEDIMENTARY ORGANIC MATTER DETERMINED BY RPO/ACCELERATOR MASS SPECTROMETRY},
	journal = {RADIOCARBON},
	volume = {61},
	number = {2},
	year = {2019},
	month = {APR},
	pages = {395-413},
	abstract = {In practice, obtaining radiocarbon (C-14) composition of organic matter (OM) in sediments requires first removing inorganic carbon (IC) by acid-treatment. Two common treatments are acid rinsing and fumigation. Resulting C-14 content obtained by different methods can differ, but underlying causes of these differences remain elusive. To assess the influence of different acid-treatments on C-14 content of sedimentary OM, we examine the variability in C-14 content for a range of marine and river sediments. By comparing results for unacidified and acidified sediments [HCl rinsing (Rinse(HCl)) and HCl fumigation (Fume(HCl))], we demonstrate that the two acid-treatments can affect C-14 content differentially. Our findings suggest that, for low-carbonate samples, Rinse(HCl) affects the Fm values due to loss of young labile organic carbon (OC). Fume(HCl) makes the Fm values for labile OC decrease, leaving the residual OC older. High-carbonate samples can lose relatively old organic components during Rinse(HCl), causing the Fm values of remaining OC to increase. Fume(HCl) can remove thermally labile, usually young, OC and reduce the Fm values. We suggest three factors should be taken into account when using acid to remove carbonate from sediments: IC abundance, proportions of labile and refractory OC, and environmental matrix.},
	issn = {0033-8222},
	doi = {10.1017/RDC.2018.125},
	author = {Bao, Rui and McNichol, Ann P. and Hemingway, Jordon D. and Gaylord, Mary C. Lardie and Eglinton, I, Timothy}
}
@article {2665,
	title = {Selective Preservation of Coccolith Calcite in Ontong-Java Plateau Sediments},
	journal = {Paleoceanography and Paleoclimatology},
	volume = {34},
	year = {2019},
	month = {May-12-2021},
	pages = {2141 - 2157},
	keywords = {BIOMINERALIZATION, caco3 dissolution, CEARA RISE, dissolution kinetics, IN-SITU MEASUREMENTS; DEEP-SEA CARBONATES; PLANKTONIC-FORAMINIFERA; EQUATORIAL PACIFIC, surface sediments, WATER INTERFACE},
	issn = {2572-4517},
	doi = {10.1029/2019PA003731},
	url = {https://apps.webofknowledge.com/InboundService.do?product=WOS\&Func=Frame\&DestFail=http\%3A\%2F\%2Fwww.webofknowledge.com\&SrcApp=search\&SrcAuth=Alerting\&SID=8DpsdyQUduuojUwg61F\&customersID=Alerting\&mode=FullRecord\&IsProductCode=Yes\&AlertId=ab9062f8-b111-4f95-},
	author = {Subhas, Adam V. and McCorkle, Daniel C. and Quizon, Alex and McNichol, Ann P. and Long, Matthew H.}
}
@article {2757,
	title = {Significance of Perylene for Source Allocation of Terrigenous Organic Matter in Aquatic SedimentsSignificance of Perylene for Source Allocation of Terrigenous Organic Matter in Aquatic Sediments},
	journal = {Environmental Science \& Technology},
	volume = {53},
	year = {2019},
	month = {Apr-07-2020},
	pages = {8244 - 8251},
	abstract = {Perylene is a frequently abundant, and sometimes the only polycyclic aromatic hydrocarbon (PAH) in aquatic sediments, but its origin has been subject of a longstanding debate in geochemical research and pollutant forensics because its historical record differs markedly from typical anthropogenic PAHs. Here we investigate whether perylene serves as a source-specific molecular marker of fungal activity in forest soils. We use a well-characterized sedimentary record (1735-1999) from the anoxic-bottom waters of the Pettaquamscutt River basin, RI to examine mass accumulation rates and isotope records of perylene, and compare them with total organic carbon and the anthropogenic PAH fluoranthene. We support our arguments with radiocarbon (14C) data of higher plant leaf-wax n-alkanoic acids. Isotope-mass balance-calculations of perylene and n-alkanoic acids indicate that \~{}40\% of sedimentary organic matter is of terrestrial origin. Further, both terrestrial markers are pre-aged on millennial time-scales prior to burial in sediments and are insensitive to elevated 14C concentrations following nuclear weapons testing in the mid-20th Century. Instead, changes coincide with enhanced erosional flux during urban sprawl. These findings suggest that perylene is definitely a product of soil-derived fungi, and a powerful chemical tracer to study the spatial and temporal connectivity between terrestrial and aquatic environments. },
	issn = {0013-936X},
	doi = {10.1021/acs.est.9b0234410.1021/acs.est.9b02344.s001},
	url = {https://pubs.acs.org/doi/10.1021/acs.est.9b02344},
	author = {Hanke, Ulrich M. and Lima-Braun, Ana L. and Eglinton, Timothy I. and Donnelly, Jeffrey P. and Galy, Valier and Poussart, Pascale and Hughen, Konrad and McNichol, Ann P. and Xu, Li and Reddy, Christopher M.}
}
@article {2789,
	title = {The effect of sample drying temperature on marine particulate organic carbon composition},
	journal = {Limnology and Oceanography: Methods},
	volume = {16},
	year = {2018},
	month = {Jan-05-2018},
	pages = {286 - 298},
	abstract = {Compositional changes in marine particulate organic carbon (POC) throughout the water column trace important processes that underlie the biological pump{\textquoteright}s efficiency. While labor-intensive, particle sampling efforts offer potential to expand the empirical POC archive at different stages in the water column, provided that organic composition is sufficiently preserved between sampling and analysis. The standard procedure for preserving organic matter composition in marine samples is to immediately store particles at -80{\textdegree}C to -20{\textdegree}C until they can be freeze-dried for analysis. This report investigates the effect of warmer drying and storage temperatures on POC composition, which applies to the majority of POC samples collected in the field without intention for organic analysis. Particle samples collected off Woods Hole, Massachusetts were immediately dried at 56{\textdegree}C, at room temperature, or stored in a freezer until freeze-drying. Results show that oven- and air-drying did not shift the bulk composition (i.e., carbon and nitrogen content and stable isotope composition) of POC in the samples relative to freeze-drying. Similarly, warmer drying temperatures did not affect POC thermal stability, as inferred by ramped pyrolysis/oxidation, a growing technique that uses a continuous temperature ramp to differentiate components of organic carbon by their decomposition temperature. Oven- and air-drying did depress lipid abundances relative to freeze-drying, the extent of which depended on compound size and structure. The data suggest that field samples dried at room temperatures and 56{\textdegree}C are appropriate for assessing bulk POC composition and thermal stability, but physical mechanisms such as molecular volatilization bias their lipid composition.},
	doi = {10.1002/lom3.v16.510.1002/lom3.10245},
	url = {https://www.researchgate.net/publication/324893072_The_effect_of_sample_drying_temperature_on_marine_particulate_organic_carbon_composition},
	author = {Rosengard, Sarah Z. and Lam, Phoebe J. and McNichol, Ann P. and Johnson, Carl G. and Galy, Valier V.}
}
@article {2604,
	title = {Tectonically-triggered sediment and carbon export to the Hadal zone},
	journal = {Nature Communications},
	volume = {9},
	year = {2018},
	month = {Jan-12-2018},
	abstract = {Sediments in deep ocean trenches may contain crucial information on past earthquake history
and constitute important sites of carbon burial. Here we present 14C data on bulk organic
carbon (OC) and its thermal decomposition fractions produced by ramped pyrolysis/oxidation
for a core retrieved from the >7.5 km-deep Japan Trench. High-resolution 14C measurements,
coupled with distinctive thermogram characteristics of OC, reveal hemipelagic
sedimentation interrupted by episodic deposition of pre-aged OC in the trench. Low δ13C
values and diverse 14C ages of thermal fractions imply that the latter material originates from
the adjacent margin, and the co-occurrence of pre-aged OC with intervals corresponding to
known earthquake events implies tectonically triggered, gravity-flow-driven supply. We show
that 14C ages of thermal fractions can yield valuable chronological constraints on sedimentary
sequences. Our findings shed new light on links between tectonically driven sedimentological
processes and marine carbon cycling, with implications for carbon dynamics in hadal
environments.},
	issn = {2041-1723},
	doi = {10.1038/s41467-017-02504-1},
	url = {http://www.nature.com/articles/s41467-017-02504-1http://www.nature.com/articles/s41467-017-02504-1.pdfhttp://www.nature.com/articles/s41467-017-02504-1.pdfhttp://www.nature.com/articles/s41467-017-02504-1},
	author = {Bao, Rui and Strasser, Michael and McNichol, Ann P. and Haghipour, Negar and McIntyre, Cameron and Wefer, Gerold and Eglinton, Timothy I.}
}
@article {1284,
	title = { Allochthonous sources and dynamic cycling of ocean dissolved organic carbon revealed by carbon isotopes},
	journal = {GEOPHYSICAL RESEARCH LETTERS},
	volume = {44},
	year = {2017},
	month = {03/2017},
	pages = {2407-2415},
	abstract = {We present concentration and isotopic profiles of total, size, and polarity fractionated dissolved organic carbon (DOC) from Station ALOHA (A Long-term Oligotrophic Habitat Assessment), an oligotrophic site in the North Pacific Ocean. The data show that, between the surface and 3500 m, low molecular weight (LMW) hydrophilic DOC, LMW hydrophobic DOC, and high molecular weight (HMW) DOC constitute 22-33\%, 45-52\%, and 23-35\% of DOC, respectively. LMW hydrophilic DOC is more isotopically depleted (delta C-13 of -23.9 parts per thousand to -31.5 parts per thousand and Delta C-14 of -304 parts per thousand to -795 parts per thousand; mean age of 2850 to 15000 years) than the LMW hydrophobic DOC (delta C-13 of -22 parts per thousand to -23 parts per thousand and Delta C-14 of -270 parts per thousand to -568 parts per thousand; 2470 to 6680 years) and HMW DOC (delta C-13 of similar to-21 parts per thousand and Delta C-14 of -24 parts per thousand to -294 parts per thousand; 135-2700 years). Our analyses suggest that a large fraction of DOC may be derived from allochthonous sources such as terrestrial and hydrothermal DOC and cycle on much longer time scales of > 10000 years or enter the ocean as preaged carbon.},
	keywords = {ATLANTIC BIGHT, BLACK CARBON, C-14, HUMIC SUBSTANCES, MATTER, NORTH PACIFIC-OCEAN, RADIOCARBON ANALYSIS, SARGASSO SEA, SEAWATER, SPECTROMETRY},
	doi = {10.1002/2016GL071348},
	author = {Zigah, Prosper K. and McNichol, Ann P. and Xu, Li and Johnson, Carl and Santinelli, Chiara and Karl, David M. and Repeta, Daniel J.}
}
@article {2805,
	title = {What on Earth Have We Been Burning? Deciphering Sedimentary Records of Pyrogenic CarbonWhat on Earth Have We Been Burning? Deciphering Sedimentary Records of Pyrogenic Carbon},
	journal = {Environmental Science \& Technology},
	volume = {51},
	year = {2017},
	month = {Jul-11-2017},
	pages = {12972 - 12980},
	abstract = {Humans have interacted with fire for thousands of years, yet the utilization of fossil fuels marked the beginning of a new era. Ubiquitous in the environment, pyrogenic carbon (PyC) arises from incomplete combustion of biomass and fossil fuels, forming a continuum of condensed aromatic structures. Here, we develop and evaluate 14C records for two complementary PyC molecular markers, benzene polycarboxylic acids (BPCAs) and polycyclic aromatic hydrocarbons (PAHs), preserved in aquatic sediments from a suburban and a remote catchment in the United States (U.S.) from the mid-1700s to 1998. Results show that the majority of PyC stems from local sources and is transferred to aquatic sedimentary archives on subdecadal to millennial time scales. Whereas a small portion stems from near-contemporaneous production and sedimentation, the majority of PyC (\~{}90\%) experiences delayed transmission due to {\textquotedblleft}preaging{\textquotedblright} on millennial time scales in catchment soils prior to its ultimate deposition. BPCAs (soot) and PAHs (precursors of soot) trace fossil fuel-derived PyC. Both markers parallel historical records of the consumption of fossil fuels in the U.S., yet never account for more than 19\% total PyC. This study demonstrates that isotopic characterization of multiple tracers is necessary to constrain histories and inventories of PyC and that sequestration of PyC can markedly lag its production.},
	issn = {0013-936X},
	doi = {10.1021/acs.est.7b03243},
	url = {https://pubs.acs.org/doi/10.1021/acs.est.7b03243},
	author = {Hanke, Ulrich M. and Reddy, Christopher M. and Braun, Ana L. L. and Coppola, Alysha I. and Haghipour, Negar and McIntyre, Cameron P. and Wacker, Lukas and Xu, Li and McNichol, Ann P. and Abiven, Samuel and Schmidt, Michael W. I. and Eglinton, Timothy I.}
}
@article {14,
	title = {Quantification of refractory organic material in Amazon mudbanks of the French Guiana Coast},
	journal = {Marine Geology},
	volume = {363},
	year = {2015},
	pages = {93-101},
	abstract = {Sub-oxic overturning mudbanks originating in the Amazon outlet and traveling northwestward along the coast of South America store 3.5 Tg organic carbon on the Amazon shelf, annually. The predominance of old soil carbon burial associated with the sediment has been supported by relatively old bulk radiocarbon ages (~ 2200{\textendash}3200 14C y) reported, but this amount has yet to be quantified for this dynamic setting. Here, we employ ramped pyrolysis radiocarbon dating to mudbank sediments from three cores to further constrain the amount of refractory sedimentary organic carbon present. Using radiocarbon age as a proxy for reactivity, we find that at least 36\% of this organic carbon is pre-aged refractory terrestrial organic carbon, likely sourced from terrestrial soils and averaging ages of 16,100 {\textpm} 300 14C y. This implies significant preservation of pre-aged terrestrial soil material in this marine environment despite the mobility and oxygen availability in the muds. Concurrently, an average of 77\% of this organic material is aged over 1000 14C y, consistent with previous estimates that the majority of organic carbon buried along the shelf is refractory. Analyses of extracted lignin phenols and terrestrial humic acids also support this preservation of refractory terrestrial material. These data indicate that sediment discharged from the Amazon River may preserve refractory terrestrial carbon in marine sediments at a minimum of 3.1 Tg C/y, which is more efficient than originally thought.},
	issn = {0025-3227},
	doi = {10.1016/j.margeo.2015.02.009},
	url = {http://www.sciencedirect.com/science/article/pii/S0025322715000456},
	author = {Williams, Elizabeth K. and Rosenheim, Brad E. and Allison, Mead and McNichol, Ann P. and Xu, Li}
}
@article {22,
	title = {Source-age dynamics of estuarine particulate organic matter using fatty acid delta C-13 and Delta C-14 composition},
	journal = {Limnology and Oceanography},
	volume = {60},
	year = {2015},
	note = {PT: J; TC: 0; UT: WOS:000351126500020},
	pages = {611-628},
	abstract = {This study used a multiproxy approach to elucidate the source and age composition of estuarine particulate organic matter (POM) using bulk stable isotopes (C-13(POC)), fatty acid (FA) biomarkers, and compound specific isotopic analyses in surface waters along the Delaware River and Bay (Delaware Estuary, hereafter). C-13 values of FA (C-13(FA)) ranged more widely (-30.9 parts per thousand to -21.8 parts per thousand) than C-13(POC) (-27.5 parts per thousand to -23.5 parts per thousand), providing greater insight about POM sources along the estuary. C-13 values of C-16:0 phospholipid FA (primarily, aquatic sources) increased along the salinity gradient (-29.8 parts per thousand to -23.4 parts per thousand), while C-13(FA) values of long-chain neutral fatty acid (terrestrial sources) decreased (-28.6 parts per thousand to -30.9 parts per thousand). C-13(FA) values for C-18{\textquoteright}s FA indicated the importance of marsh-derived organic matter within Delaware Estuary. Compound specific radiocarbon analysis showed the heterogeneous age structure of FA associated with POM (FA(POM)). C-14 ages of FA ranged from modern (postbomb) to 1790BP; aged FA (120BP to 1700BP) derived primarily from the watershed, whereas modern FA were produced within Delaware Estuary. C-14 ages of short-chain FA (aquatic sources) reflected differences in the age of dissolved inorganic carbon along the estuary and had older C-14 ages at the river end-member. C-14 ages of FA from terrigenous sources were older than water and sediment residence times indicating this source derived from the watershed. This study is the first to document the complex age distribution of FA(POM) along the estuarine salinity gradient and shows that inorganic carbon sources, watershed inputs and autochthonous production contribute to variation in the ages of POM.},
	issn = {0024-3590},
	doi = {10.1002/lno.10053},
	author = {McIntosh, Hadley A. and McNichol, Ann P. and Xu, Li and Canuel, Elizabeth A.}
}
@article {15,
	title = {Ultra-Small Graphitization Reactors for Ultra-Microscale C-14 Analysis at the National Ocean Sciences Accelerator Mass Spectrometry (Nosams) Facility},
	journal = {Radiocarbon},
	volume = {57},
	year = {2015},
	note = {PT: J; TC: 1; UT: WOS:000351052600009},
	pages = {109-122},
	abstract = {In response to the increasing demand for C-14 analysis of samples containing less than 25 mu g C, ultra-small graphitization reactors with an internal volume of similar to 0.8 mL were developed at NOSAMS. For samples containing 6 to 25 mu g C, these reactors convert CO2 to graphitic carbon in approximately 30 min. Although we continue to refine reaction conditions to improve yield, the reactors produce graphite targets that are successfully measured by AMS. Graphite targets produced with the ultra-small reactors are measured by using the Cs sputter source on the CFAMS instrument at NOSAMS where beam current was proportional to sample mass. We investigated the contribution of blank carbon from the ultra-small reactors and estimate it to be 0.3 +/- 0.1 mu g C with an Fm value of 0.43 +/- 0.3. We also describe equations for blank correction and propagation of error associated with this correction. With a few exceptions for samples in the range of 6 to 7 mu g C, we show that corrected Fm values agree with expected Fm values within uncertainty for samples containing 6-100 mu g C.},
	issn = {0033-8222},
	doi = {10.2458/azu_rc.57.18118},
	author = {Walter, Sunita R. Shah and Gagnon, Alan R. and Roberts, Mark L. and McNichol, Ann P. and Gaylord, Mary C. Lardie and Klein, Elizabeth}
}
@article {108,
	title = {14C and 13C characteristics of higher plant biomarkers in Washington margin surface sediments},
	journal = {Geochimica et Cosmochimica Acta},
	volume = {105},
	year = {2013},
	note = {id: 2267},
	pages = {14-30},
	abstract = {Plant wax lipids and lignin phenols are the two most common classes of molecular markers that are used to trace vascular plant-derived OM in the marine environment. However, their 13C and 14C compositions have not been directly compared, which can be used to constrain the flux and attenuation of terrestrial carbon in marine environment. In this study, we describe a revised method of isolating individual lignin phenols from complex sedimentary matrices for 14C analysis using high pressure liquid chromatography (HPLC) and compare this approach to a method utilizing preparative capillary gas chromatography (PCGC). We then examine in detail the 13C and 14C compositions of plant wax lipids and lignin phenols in sediments from the inner and mid shelf of the Washington margin that are influenced by discharge of the Columbia River. Plant wax lipids (including n-alkanes, n-alkanoic (fatty) acids, n-alkanols, and n-aldehydes) displayed significant variability in both δ13C (-28.3{\textperthousand} to -37.5{\textperthousand}) and Δ14C values (-204{\textperthousand} to +2{\textperthousand}), suggesting varied inputs and/or continental storage and transport histories. In contrast, lignin phenols exhibited similar δ13C values (between -30{\textperthousand} and -34{\textperthousand}) and a relatively narrow range of Δ14C values (-45{\textperthousand} to -150{\textperthousand}; HPLC-based measurement) that were similar to, or younger than, bulk OM (-195{\textperthousand} to -137{\textperthousand}). Moreover, lignin phenol 14C age correlated with the degradation characteristics of this terrestrial biopolymer in that vanillyl phenols were on average \~{}500 years older than syringyl and cinnamyl phenols that degrade faster in soils and sediments. The isotopic characteristics, abundance, and distribution of lignin phenols in sediments suggest that they serve as promising tracers of recently biosynthesized terrestrial OM during supply to, and dispersal within the marine environment. Lignin phenol 14C measurements may also provide useful constraints on the vascular plant end member in isotopic mixing models for carbon source apportionment, and for interpretation of sedimentary records of past vegetation dynamics.},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2012.11.034},
	url = {http://www.sciencedirect.com/science/article/pii/S0016703712006874},
	author = {Feng, Xiaojuan and Benitez-Nelson, Bryan C. and Montlu{\c c}on, Daniel B. and Prahl, Fredrick G. and McNichol, Ann P. and Xu, Li and Repeta, Daniel J. and Eglinton, Timothy I.}
}
@article { ISI:000315194800002,
	title = {C-14 and C-13 characteristics of higher plant biomarkers in Washington margin surface sediments},
	journal = {GEOCHIMICA ET COSMOCHIMICA ACTA},
	volume = {105},
	year = {2013},
	month = {MAR 15},
	pages = {14-30},
	type = {Article},
	abstract = {Plant wax lipids and lignin phenols are the two most common classes of molecular markers that are used to trace vascular plant-derived OM in the marine environment. However, their C-13 and C-14 compositions have not been directly compared, which can be used to constrain the flux and attenuation of terrestrial carbon in marine environment. In this study, we describe a revised method of isolating individual lignin phenols from complex sedimentary matrices for C-14 analysis using high pressure liquid chromatography (HPLC) and compare this approach to a method utilizing preparative capillary gas chromatography (PCGC). We then examine in detail the C-13 and C-14 compositions of plant wax lipids and lignin phenols in sediments from the inner and mid shelf of the Washington margin that are influenced by discharge of the Columbia River. Plant wax lipids (including n-alkanes, n-alkanoic (fatty) acids, n-alkanols, and n-aldehydes) displayed significant variability in both delta C-13 (-28.3 parts per thousand to -37.5 parts per thousand) and Delta C-14 values (-204 parts per thousand to +2 parts per thousand), suggesting varied inputs and/or continental storage and transport histories. In contrast, lignin phenols exhibited similar delta C-13 values (between -30 parts per thousand and -34 parts per thousand) and a relatively narrow range of Delta C-14 values (-45 parts per thousand to -150 parts per thousand; HPLC-based measurement) that were similar to, or younger than, bulk OM (-195 parts per thousand to -137 parts per thousand). Moreover, lignin phenol C-14 age correlated with the degradation characteristics of this terrestrial biopolymer in that vanillyl phenols were on average similar to 500 years older than syringyl and cinnamyl phenols that degrade faster in soils and sediments. The isotopic characteristics, abundance, and distribution of lignin phenols in sediments suggest that they serve as promising tracers of recently biosynthesized terrestrial OM during supply to, and dispersal within the marine environment. Lignin phenol C-14 measurements may also provide useful constraints on the vascular plant end member in isotopic mixing models for carbon source apportionment, and for interpretation of sedimentary records of past vegetation dynamics. (C) 2012 Elsevier Ltd. All rights reserved.},
	issn = {0016-7037},
	doi = {10.1016/j.gca.2012.11.034},
	author = {Feng, Xiaojuan and Benitez-Nelson, Bryan C. and Montlu{\c c}on, Daniel B. and Prahl, Fredrick G. and McNichol, Ann P. and Xu, Li and Repeta, Daniel J. and Eglinton, Timothy I.}
}
@article {121,
	title = {Correction to" Isotopic characterization of aerosol organic carbon components over the eastern United States" (vol 117, D13303, 2012)},
	journal = {Journal of Geophysical Research-Atmospheres},
	volume = {117},
	year = {2012},
	note = {id: 2251; PT: J; TC: 0; UT: WOS:000307471700004},
	pages = {D15399-D15399},
	issn = {0148-0227},
	doi = {10.1029/2012JD018478},
	author = {Wozniak, Andrew S. and Bauer, James E. and Dickhut, Rebecca M. and Xu, Li and McNichol, Ann P.}
}
@article {122,
	title = {Isotopic characterization of aerosol organic carbon components over the eastern United States},
	journal = {Journal of Geophysical Research-Atmospheres},
	volume = {117},
	year = {2012},
	note = {id: 2252; PT: J; TC: 1; UT: WOS:000306237000001},
	pages = {D13303-D13303},
	abstract = {Carbon isotopic signatures (delta C-13, Delta C-14) of aerosol particulate matter total organic carbon (TOC) and operationally defined organic carbon (OC) components were measured in samples from two background sites in the eastern U. S. TOC and water-soluble OC (WSOC) delta C-13 values (-27 to -24 parts per thousand) indicated predominantly terrestrial C-3 plant and fossil derived sources. Total solvent extracts (TSE) and their aliphatic, aromatic, and polar OC components were depleted in delta C-13 (-30 to -26 parts per thousand) relative to TOC and WSOC. Delta C-14 signatures of aerosol TOC and TSE (-476 to +25 parts per thousand) suggest variable fossil contributions (similar to 5-50\%) to these components. Aliphatic OC while comprising a small portion of the TOC (},
	issn = {0148-0227},
	doi = {10.1029/2011JD017153},
	author = {Wozniak, Andrew S. and Bauer, James E. and Dickhut, Rebecca M. and Xu, Li and McNichol, Ann P.}
}
@article {164,
	title = {A two-dimensional, heart-cutting preparative gas chromatograph facilitates highly resolved single-compound isolations with utility towards compound-specific natural abundance radiocarbon (14C) analyses},
	journal = {Journal of Chromatography A},
	volume = {1220},
	year = {2012},
	note = {id: 2152},
	pages = {122-131},
	abstract = {Motivated by the need to develop clean, high purity preparative enrichments of individual compounds for micro-scale compound-specific natural abundance isotope and radiocarbon (14C) analyses, we describe a new, two-dimensional, heart-cutting, low-bleed, three-oven, single GC preparative system, demonstrate its resolving capabilities as applied to a typically complex environmental sample matrix, and investigate the robustness with which it preserves the authigenic 13C/12C and 14C/12C ratios of individual compounds it targets for preparative enrichment. The system is comprised of a programmable temperature vaporizing (PTV) inlet, a single GC oven, two modular, door-mounted, resistively heated low thermal mass (LTM) columns, a preparative fraction collector (PFC), and a Deans pneumatic switching device which facilitates heart-cutting between the system{\textquoteright}s 1{\textdegree} and 2{\textdegree} chromatographic dimensions. Further, the system{\textquoteright}s inlet and trapping parameters are optimized for the efficient preparative enrichment of the methyl ether and ester derivatives of the lignin phenol compound class. The lignin phenols include such compounds as the vanillyl and syringyl aldehydes, ethanones, and acids and are unrivaled biomarkers of terrestrial organic matter, some of which are also important components of fragrances and flavors. Using this suite of compounds, the suitability of this augmented preparative capillary GC (PCGC) system was investigated for micro-scale compound-specific (CS) stable isotope and natural abundance radiocarbon analyses (RA). Analysis of a >300 injection enrichment scheme reveals the instrument to fractionate 13C in predictable ways and to preserve the authigenic Δ14C of compounds it targets for preparative enrichment to within 6.7 {\textpm} 5.0{\textperthousand}, demonstrating the promising new utility of such systems towards micro-scale CSRA investigations for which clean and high resolution separation techniques are prerequisite.},
	issn = {0021-9673},
	doi = {10.1016/j.chroma.2011.11.021},
	url = {http://www.sciencedirect.com/science/article/pii/S0021967311017031},
	author = {Ball, Gregory Ian and Xu, Li and McNichol, Ann P. and Aluwihare, Lihini I.}
}
@article {197,
	title = {Rapid radiocarbon ((14)C) analysis of coral and carbonate samples using a continuous-flow accelerator mass spectrometry (CFAMS) system},
	journal = {Paleoceanography},
	volume = {26},
	year = {2011},
	note = {id: 1915; PT: J; UT: WOS:000296649300001},
	pages = {PA4212-PA4212},
	abstract = {Radiocarbon analyses of carbonate materials provide critical information for understanding the last glacial cycle, recent climate history and paleoceanography. Methods that reduce the time and cost of radiocarbon ((14)C) analysis are highly desirable for large sample sets and reconnaissance type studies. We have developed a method for rapid radiocarbon analysis of carbonates using a novel continuous-flow accelerator mass spectrometry (CFAMS) system. We analyzed a suite of deep-sea coral samples and compared the results with those obtained using a conventional AMS system. Measurement uncertainty is},
	issn = {0883-8305},
	doi = {10.1029/2011PA002174},
	author = {McIntyre, Cameron P. and Roberts, Mark L. and Burton, Joshua R. and McNichol, Ann P. and Burke, Andrea and Robinson, Laura F. and von Reden, Karl F. and W. J. Jenkins}
}
@article { ISI:000277965100004,
	title = {Coastal New England pilot study to determine fossil and biogenic formaldehyde source contributions using radiocarbon},
	journal = {JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES},
	volume = {115},
	year = {2010},
	month = {MAY 18},
	type = {Article},
	abstract = {Compound specific radiocarbon analyses of atmospheric formaldehyde are reported as fraction modern (Fm) for a limited number of winter and summer air samples collected in coastal southern New England in 2007. The 11 of 13 samples with Fm < 0.2 were collected under the influence of the semipermanent Bermuda high-pressure system with transport from the Washington, D. C., to New York City urban corridor. The two samples with Fm > 0.2 (max similar to 0.35) were collected on days with strong northwesterly flow and the least urban impact. The Fm data were combined with VOC observations from the Rhode Island Department of Environmental Management, estimates of oxygenated VOC (OVOC), and back trajectories to interpret the relative contributions of biogenic and fossil carbon sources. It is argued that CH2O sources were dominated by pollutant VOCs and OVOCs from upwind coastal cities as opposed to more local biogenic VOCs at the times of sample collection.},
	issn = {2169-897X},
	doi = {10.1029/2009JD012810},
	author = {Shen, Haiwei and Heikes, Brian G. and Merrill, John T. and McNichol, Ann P. and Xu, Li}
}
@article {459,
	title = {Comparative AMS radiocarbon dating of pretreated versus non-pretreated tropical wood samples},
	journal = {Nuclear Instruments \& Methods in Physics Research Section B-Beam Interactions with Materials and Atoms},
	volume = {268},
	year = {2010},
	note = {id: 2083; PT: J; CT: 11th International Conference on Accelerator Mass Spectrometry; CY: SEP 14-19, 2008; CL: Rome, ITALY; SP: Univ Salento, CEDAD, Second Univ Naples, CIRCE, INNOVA, Ist Nazl Fis Nucl, LABEC, Abdus Salam Int Ctr Theoret Phys; UT: WOS:000277462300058},
	pages = {910-913},
	abstract = {Several wood samples collected from Dorslandboom, a large iconic African baobab (Adansonia digitata L.) from Namibia, were investigated by AMS radiocarbon dating subsequent to pretreatment and, alternatively, without pretreatment. The comparative statistical evaluation of results showed that there were no significant differences between fraction modern values and radiocarbon dates of the samples analyzed after pretreatment and without pretreatment, respectively. The radiocarbon date of the oldest sample was 993 +/- 20 BP. Dating results also revealed that Dorslandboom is a multi-generation tree, with several stems showing different ages. (C) 2009 Elsevier B.V. All rights reserved.},
	issn = {0168-583X},
	doi = {10.1016/j.nimb.2009.10.062},
	author = {Patrut, Adrian and von Reden, Karl F. and Lowy, Daniel A. and Mayne, Diana H. and Elder, Kathryn E. and Roberts, Mark L. and McNichol, Ann P.}
}
@article { ISI:000281306000013,
	title = {Radiocarbon Dating of Individual Lignin Phenols: A New Approach for Establishing Chronology of Late Quaternary Lake Sediments},
	journal = {ANALYTICAL CHEMISTRY},
	volume = {82},
	number = {{17}},
	year = {2010},
	month = {SEP 1},
	pages = {7119-7126},
	type = {Article},
	abstract = {The reliability of chronology is a prerequisite for meaningful paleoclimate reconstructions from sedimentary archives. The conventional approach of radiocarbon dating bulk organic carbon in lake sediments is often hampered by the old carbon effect, i.e., the assimilation of ancient dissolved inorganic carbon (DIC) derived from carbonate bedrocks or other sources. Therefore, radiocarbon dating is ideally performed on organic compounds derived from land plants that use atmospheric CO(2) and rapidly delivered to sediments. We demonstrate that lignin phenols isolated from lake sediments using reversed phase high performance liquid chromatography (HPLC) can serve as effective (14)C dating materials for establishing chronology during the late Quaternary. We developed a procedure to purify lignin phenols, building upon a published method. By isolating lignin from standard wood reference substances, we show that our method yields pure lignin phenols and consistent ages as the consensus ages and that our procedure does not introduce radiocarbon contamination. We further demonstrate that lignin phenol ages are compatible with varve counted and macrofossil dated sediment horizons in Steel Lake and Fayetteville Green Lake. Applying the new method to lake sediment cores from Lake Qinghai demonstrates that lignin phenol ages in Lake Qinghai are consistently younger than bulk total organic carbon (TOC) ages which are contaminated by old carbon effect. We also show that the age offset between lignin and bulk organic carbon differs at different Lake Qinghai sedimentary horizons, suggesting a variable hard water effect at different times and that a uniform age correction throughout the core is inappropriate.},
	issn = {0003-2700},
	doi = {10.1021/ac100494m},
	author = {Hou, Juzhi and Huang, Yongsong and Brodsky, Corynn and Alexandre, Marcelo R. and McNichol, Ann P. and King, John W. and Hu, Feng Sheng and Shen, Ji}
}
@article {506,
	title = {Reconnaissance dating A new radiocarbon method applied to assessing the temporal distribution of Southern Ocean deep-sea corals},
	journal = {Deep-Sea Research Part I-Oceanographic Research Papers},
	volume = {57},
	year = {2010},
	note = {id: 1924; PT: J; UT: WOS:000284750700012},
	pages = {1510-1520},
	abstract = {We have developed a rapid reconnaissance method of preparing graphite for (14)C/(12)C analysis Carbonate (similar to 15 mg) is combusted using an elemental analyzer and the resulting CO(2) is converted to graphite using a sealed tube zinc reduction method Over 85\% (n=45 replicates on twenty-one individual corals) of reconnaissance ages measured on corals ranging in age from 500 to 33 000 radiocarbon years (Ryr) are within two standard deviations of ages generated using standard hydrolysis methods on the same corals and all reconnaissance ages are within 300 Ryr of the standard hydrolysis ages Replicate measurements on three individual aragonitic corals yielded ages of 1076 +/- 35 Ryr (standard deviation n=5) 10 739 +/- 47 Ryr (n=8) and 40 146 +/- 3500 Ryr (n=9) No systematic biases were found using different cleaning methods or variable sample sizes Analysis of (13)C/(12)C was made concurrently with the (14)C/(12)C measurement to correct for natural fractionation and for fractionation during sample processing and analysis This technique provides a new rapid method for making accurate percent-level (14)C/(12)C analyses that may be used to establish the rates and chronology of earth system processes where survey-type modes of age estimation are desirable For example applications may include creation of sediment core-top maps preliminary age models for sediment cores and growth rate studies of marine organisms such as corals or mollusks We applied the reconnaissance method to more than 100 solitary deep-sea corals collected in the Drake Passage in the Southern Ocean to investigate their temporal and spatial distribution The corals used in this study are part of a larger sample set and the subset that was dated was chosen based on species as opposed to preservation state so as to exclude obvious temporal biases Similar to studies in other regions the distribution of deep-sea corals is not constant through time across the Drake Passage Most of the corals from the Burdwood Bank (continental shelf of Argentina) have ages ranging between 0 and 2500 calendar years whereas most of the corals from the Sars Seamount in the Drake Passage have ages between 10 000 and 12 500 calendar years Such differences may be caused in part by sampling biases but may also be caused by changes in larval transport nutrient supply or other environmental pressures (C) 2010 Elsevier Ltd All rights reserved},
	issn = {0967-0637},
	doi = {10.1016/j.dsr.2010.07.010},
	author = {Burke, Andrea and Robinson, Laura F. and McNichol, Ann P. and W. J. Jenkins and Scanlon, Kathryn M. and Gerlach, Dana S.}
}
@article { ISI:000268455600046,
	title = {Radiocarbon Analysis of Atmospheric Formaldehyde Using Cystamine Derivatization},
	journal = {ANALYTICAL CHEMISTRY},
	volume = {81},
	number = {{15}},
	year = {2009},
	month = {AUG 1},
	pages = {6310-6316},
	type = {Article},
	abstract = {A compound specific radiocarbon analysis method was developed to evaluate the C-14 composition of atmospheric formaldehyde. In this method, gaseous formaldehyde was collected with a high-volume air sampler using glass-fiber filters pretreated with sodium bisulfite. Collected formaldehyde was then released into water and derivatized with cysteamine to thiazolidine. The thiazolidine was extracted into dichloromethane and concentrated by evaporation. Concentrated thiazolidine was separated from other compounds using preparative capillary gas chromatography and uniquely collected as a phosphate salt with a fraction collector. The C-14 composition of the salt was analyzed by accelerator mass spectrometry after combustion to CO2 and subsequent reduction to graphite. In a pilot study, ambient formaldehyde samples collected on the roof of the CACS building at Narragansett Bay Campus, Narragansett, RI, showed a significantly larger fraction of fossil carbon than modern carbon.},
	issn = {0003-2700},
	doi = {10.1021/ac9004666},
	author = {Shen, Haiwei and McNichol, Ann P. and Xu, Li and Gagnon, Alan and Heikes, Brian G.}
}
@article { ISI:000258791200003,
	title = {Biodiesel effects on particulate radiocarbon (C-14) emissions from a diesel engine},
	journal = {JOURNAL OF AEROSOL SCIENCE},
	volume = {39},
	number = {{8}},
	year = {2008},
	month = {AUG},
	pages = {667-678},
	type = {Article},
	abstract = {The relative amount of C-14 in a sample of atmospheric particulate matter (PM), defined as percent modern carbon (pMC), allows the Environmental Protection Agency (EPA) to infer the fraction of PM derived from anthropogenic pollution sources. With increased use of biofuels that contain C-14, the main assumption of the two-source model, that C-14 is solely derived from biogenic emissions, may become invalid. The goal of this study was to determine the C-14 content of PM emitted from an off-highway diesel engine running on commercial grade biodiesel. Tests were conducted with an off-highway diesel engine running at 80\% load fueled by various blends of soy-based biodiesel. A dilution tunnel was used to collect PM10 emissions on quartz filters that were analyzed for their C-14 content using accelerator mass spectrometry. A mobility particle sizer and 5-gas analyzer provided supporting information on the particle size distribution and gas-phase emissions. The pMC of PM10 aerosol increased linearly with the percentage of biodiesel present in the fuel. Therefore, PM emissions resulting from increased combustion of biodiesel fuels will likely affect contemporary C-14 apportionment efforts that attempt to split biogenic vs. anthropogenic emissions based on aerosol C-14 content. Increasing the biodiesel fuel content also reduced emissions of total hydrocarbons (THC), PM10 mass, and particulate elemental carbon. Biodiesel had variable results on oxides of nitrogen (NOx) emissions. (C) 2008 Elsevier Ltd. All rights reserved.},
	keywords = {biofuel, EC, OC, PM, source apportionment},
	issn = {0021-8502},
	doi = {10.1016/j.jaerosci.2008.04.001},
	author = {Bennett, Maren and Volckens, John and Stanglmaier, Rudy and McNichol, Ann P. and Ellenson, William D. and Lewis, Charles W.}
}
@article {2141,
	title = {Radiocarbon Dating of Wood Samples and Plutonium Sediment Disturbance Studies at the Queen Anne{\textquoteright}s Revence Wreck Site},
	journal = {Southeastern Geology},
	volume = {40},
	year = {2001},
	note = {id: 1200},
	month = {2001},
	pages = {29-40},
	author = {Martens, Christopher S. and McNichol, Ann P.}
}
@conference {1564,
	title = {The Antarctic Radiocarbon Storage Ring},
	booktitle = {8th International Conference on Accelerator Mass Spectrometry},
	year = {1999},
	note = {id: 1791},
	month = {1999},
	address = {Vienna, Austria},
	author = {Schneider, Robert J. and McNichol, Ann P. and von Reden, Karl F. and Elder, Kathryn L. and Gagnon, Alan R. and Key, Robert M. and Quay, Paul D.}
}
@article {2257,
	title = {A Correction for Aberrations in the Woods Hole Recombinator. Symposium of North-Eastern Accelerator Personnel},
	journal = {World Scientific},
	volume = {SNEAP 1996},
	year = {1998},
	note = {id: 1664},
	month = {1998},
	pages = {123-128},
	author = {Schneider, Robert J. and McNichol, Ann P. and von Reden, Karl F. and Elder, Kathryn L. and Gagnon, Allan R. and Key, Robert M. and Quay, Paul D.}
}
@conference {1691,
	title = {Microscale AMS 14C Measurement at NOSAMS},
	booktitle = {16th International 14C Conference},
	year = {1998},
	note = {id: 1502},
	month = {1998},
	author = {Pearson, Ann and McNichol, Ann P. and Schneider, Robert J. and von Reden, Karl F.}
}
@conference {1692,
	title = {Microscale AMS (super <sup>14</sup>) C measurement at NOSAMS},
	volume = {40},
	year = {1998},
	note = {id: 2237; Source type: conferencepapers\&proceedings; Object type: Article; Object type: Conference Paper; Copyright: GeoRef, Copyright 2007, American Geological Institute.; CSAUnique: 1999-044438; AccNum: 1999-044438; ISSN: 0033-8222; CODEN: RACAAT},
	month = {1998},
	pages = {61-75},
	publisher = {University of Arizona, Department of Geosciences, Tucson, AZ, United States (USA)},
	organization = {University of Arizona, Department of Geosciences, Tucson, AZ, United States (USA)},
	address = {United States (USA)},
	abstract = {Techniques for making precise and accurate radiocarbon accelerator mass spectrometry (AMS) measurements on samples containing less than a few hundred micrograms of carbon are being developed at the NOSAMS facility. A detailed examination of all aspects of the sample preparation and data analysis process shows encouraging results. Small quantities of CO (sub 2) are reduced to graphite over cobalt catalyst at an optimal temperature of 605 degrees C. Measured (super 14) C/ (super 12) C ratios of the resulting targets are affected by machine-induced isotopic fractionation, which appears directly related to the decrease in ion current generated by the smaller sample sizes. It is possible to compensate effectively for this fractionation by measuring samples relative to small standards of identical size. Examination of the various potential sources of background (super 14) C contamination indicates that the sample combustion process is the largest contributor, adding ca. 1 mu g of carbon with a less-than-modern (super 14) C concentration.},
	keywords = {03, absolute age, accelerator mass spectroscopy, accuracy, C-14, C-14/C-12, carbon, Carbon dioxide, combustion, data processing, Geochronology, graphite, isotope fractionation, isotopes, mass spectroscopy, mathematical methods, methods, native elements, radioactive isotopes, sample preparation, size, spectroscopy, Stable isotopes},
	doi = {10.1017/S0033822200017902},
	url = {http://hdl.handle.net/10150/653650},
	author = {Pearson, Ann and McNichol, Ann P. and Schneider, Robert J. and von Reden, Karl F. and Zheng, Yan}
}
@conference {1800,
	title = {(super 14) C AMS measurements of},
	volume = {40},
	year = {1998},
	note = {id: 2239; Source type: conferencepapers\&proceedings; Object type: Article; Object type: Conference Paper; Copyright: GeoRef, Copyright 2007, American Geological Institute.; CSAUnique: 1999-044459; AccNum: 1999-044459; ISSN: 0033-8222; CODEN: RACAAT},
	month = {1998},
	pages = {247-253},
	publisher = {University of Arizona, Department of Geosciences, Tucson, AZ, United States (USA)},
	organization = {University of Arizona, Department of Geosciences, Tucson, AZ, United States (USA)},
	address = {United States (USA)},
	abstract = {The NOSAMS facility at Woods Hole Oceanographic Institution has started to develop and apply techniques for measuring very small samples on a standard Tandetron accelerator mass spectrometry (AMS) system with high-current hemispherical Cs sputter ion sources. Over the past year, results on samples ranging from 7 to 160 mu g C showed both the feasibility of such analyses and the present limitations on reducing the size of solid carbon samples. One of the main factors affecting the AMS results is the dependence of a number of the beam optics parameters on the extracted ion beam current. The extracted currents range from 0.5 to 10 mu A of (super 12) C (super -) for the sample sizes given above. We here discuss the setup of the AMS system and methods for reliable small-sample measurements and give the AMS-related limits to sample size and the measurement uncertainties.},
	keywords = {03, absolute age, accelerator mass spectroscopy, C-14, carbon, dilution, Geochronology, ions, isotopes, mass spectroscopy, precision, radioactive isotopes, sample preparation, spectroscopy, volume},
	author = {von Reden, Karl F. and McNichol, Ann P. and Pearson, Ann and Schneider, Robert J.}
}
@article {2434,
	title = {Concentrations of carbonyl compounds and the carbon isotopy of formaldehyde at a coastal site in Nova Scotia during the NARE summer intensive},
	journal = {Journal of Geophysical Research: AtmospheresJ. Geophys. Res.},
	volume = {101},
	year = {1996},
	month = {1996},
	pages = {28961 - 28970},
	keywords = {0315 Biosphere/atmosphere interactions, 0345 Pollution: urban and regional, 0365 Troposphere: composition and chemistry, 0394 Instruments and techniques},
	isbn = {2156-2202},
	doi = {10.1029/95JD03574},
	url = {http://dx.doi.org/10.1029/95JD03574},
	author = {Tanner, Roger L. and Zielinska, Barbara and Uberna, Ewa and Harshfield, Gregory and McNichol, Ann P.}
}
