@article {2661,
	title = {On the Origin of Aged Sedimentary Organic Matter Along a River-Shelf-Deep Ocean Transect},
	journal = {Journal of Geophysical Research: Biogeosciences},
	volume = {124},
	year = {2019},
	month = {Jun-08-2021},
	pages = {2582 - 2594},
	abstract = {To assess the influences of carbon sources and transport processes on the C-14 age of organic matter (OM) in continental margin sediments, we examined a suite of samples collected along a river-shelf-deep ocean transect in the East China Sea (ECS). Ramped pyrolysis-oxidiation was conducted on suspended particulate matter in the Yangtze River and on surface sediments from the ECS shelf and northern Okinawa Trough. C-14 ages were determined on OM decomposition products within different temperature windows. These measurements suggest that extensive amounts of pre-old (i.e., millennial age) organic carbon (OC) are subject to degradation within and beyond the Yangtze River Delta, and this process is accompanied by an exchange of terrestrial and marine OM. These results, combined with fatty acid concentration data, suggest that both the nature and extent of OM preservation/degradation as well as the modes of transport influence the C-14 ages of sedimentary OM. Additionally, we find that the age of (thermally) refractory OC increases during across-shelf transport and that the age offset between the lowest and highest temperature OC decomposition fractions also increases along the shelf-to-trough transect. Amplified interfraction spread or C-14 heterogeneity is the greatest in the Okinawa Trough. Aged sedimentary OM across the transect may be a consequence of several reasons including fossil OC input, selective degradation of younger OC, hydrodynamic sorting processes, and aging during lateral transport. Consequently, each of them should be considered in assessing the C-14 results of sedimentary OM and its implications for the carbon cycle and interpretation of sedimentary records.},
	keywords = {Carbon cycle, hydrodynamic processes, organic carbon, radiocarbon, sediments},
	issn = {2169-8953},
	doi = {10.1029/2019JG005107},
	url = { https://doi.org/10.1029/2019JG005107},
	author = {Bao, Rui and Zhao, Meixun and McNichol, Ann and Wu, Ying and Guo, Xinyu and Haghipour, Negar and Eglinton, Timothy I.}
}
@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}
}
