@article {2931,
	title = {Using Radiocarbon to Assess the Abundance, Distribution, and Nature of Labile Organic Carbon in Marine Sediments},
	journal = {Global Biogeochemical Cycles},
	volume = {35},
	year = {2021},
	month = {Jan-06-2021},
	abstract = {Positive C-14 gradients have recently been observed within the surface mixed layer of several continental-margin sediments. The best explanation for these positive C-14 gradients is the occurrence and rapid degradation of labile organic carbon (LOC) in the upper 5-10 cm of the seabed. Based on a two-component model for sedimentary organic matter (i.e., a planktonic labile component and an older refractory component), bulk (14)Corg data were used to determine the abundances of LOC within the surface mixed layers of three cores from the West Antarctic Peninsula (WAP) shelf and one core from San Clemente Basin (California Borderland). LOC contents in surface samples from the four stations varied from 0.5 to 1.1 mg/cm(3), comprising 20\% (San Clemente Basin) to 80\% (WAP, Sta. G) of the total organic carbon. By incorporating a steady state diagenetic model and particle-mixing bioturbation coefficients, the LOC profiles were used to determine LOC turnover times (LOC tau) and LOC e-folding depths. The LOC tau values for the West Antarctic Peninsula sediments varied from 0.09 to 0.59 years, whereas the LOC tau value from the San Clemente Basin core was 63 years. The LOC e-folding depths for the WAP stations varied from 0.8 to 3.4 cm, in contrast to the LOC e-folding depth in San Clemente Basin, which was 4.0 cm. LOC characteristics from the four cores examined in this study were compared to LOC data in the literature as a means of substantiating the overall C-14(org)-based approach and justifying model assumptions.},
	issn = {0886-6236},
	doi = {10.1029/2020GB006676},
	url = {https://onlinelibrary.wiley.com/doi/10.1029/2020GB006676https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020GB006676https://onlinelibrary.wiley.com/doi/pdf/10.1029/2020GB006676https://onlinelibrary.wiley.com/doi/full-xml/10.1029/2020GB006676},
	author = {DeMaster, D. J. and Taylor, R. S. and Smith, C. R. and Isla, E. and Thomas, C. J.}
}
@article {511,
	title = {C-14 as a tracer of labile organic matter in Antarctic benthic food webs},
	journal = {Deep-Sea Research Part Ii-Topical Studies in Oceanography},
	volume = {55},
	year = {2008},
	note = {id: 1854; 386VU Times Cited:7 Cited References Count:98Y},
	pages = {2438-2450},
	abstract = {C-14 measurements were made on surface plankton, particle-trap material, surface sediment, benthic invertebrate gut contents, and body tissue samples to assess the effectiveness of this radioisotope as a tracer of labile organic carbon in Antarctic benthic food webs. Samples were collected on five cruises to the West Antarctic Peninsula (WAP) shelf between November 1999 and March 2001 as part of the Food for Benthos on the ANtarctic Continental-Shelf (FOODBANCS) Project. The 14C contents of the body tissues from a variety of deposit feeders (-126 +/- 13 per mil) were substantially enriched relative to the surface sediment (-234 +/- 13 per mil) and statistically similar to the organic matter collected in plankton tows (-135 +/- 10 per mil), indicating that recently produced marine plankton are the primary source of nutrition for these deposit feeders on the West Antarctic shelf. Selective ingestion was the primary feeding strategy used by echiuran worms and certain holothurians (i.e. Peniagone vignoni) for incorporating labile organic carbon into their tissues as demonstrated by the large differences (105 +/- 13 per mil) between surface sediment and gut content C-14 activities. In contrast, digestive and/or assimilatory, selection was the predominant strategy used by an irregular urchin (Amphipneustes lorioli) and several other holothurians (Protelpidia murrayi, Bathyplotes fuscivinculum and the head-clown conveyor belt feeder, Molpadia musculus), as demonstrated by large differences (42 +/- 7 per mil) between the 14C activities of their foregut or whole-gut organic contents and their body tissues. Despite large fluctuations in carbon export from the euphotic zone, benthic feeding strategies remained essentially constant over the 15-month sampling period. No seasonal variation was evident in either the 14C abundance of the deposit-feeder body tissues, or in the 14C abundance of their gut contents. The mean C-14 abundance in the body tissues of the two sub-surface deposit feeders (A. lorioli and M. musculus; mean = -136.2 +/- 8.5 per mil) was distinct (p = 0.0008) from the mean 14C abundance in the body tissues of the four surface deposit feeders (echiuran worm, P vignoni, P. murrayi, and B. fusciviculum; -122.6 +/- 12.3 per mil). The mean 14 C abundance of the gut contents from the sub-surface deposit feeders (-178.0 +/- 18.6 per mil) also was significantly depleted (p = 0.0009) relative to that of the surface deposit feeders (-149.5 +/- 26.6 per mil). The 14C measurements proved to be a much more sensitive tracer for tracking labile organic carbon during ingestive and assimilatory processes than the stable isotopes of carbon or nitrogen. (C) 2008 Elsevier Ltd. All rights reserved.},
	issn = {0967-0645},
	doi = {10.1016/j.dsr2.2008.06.004},
	author = {Purinton, B. L. and DeMaster, D. J. and Thomas, C. J. and Smith, C. R.}
}
@article {2092,
	title = {Organic carbon deposition on the North Carolina continental slope off Cape Hatteras (USA)},
	journal = {Deep-Sea Research Part Ii-Topical Studies in Oceanography},
	volume = {49},
	year = {2002},
	note = {607kxTimes Cited:31
Cited References Count:77
},
	month = {2002},
	pages = {4687-4709},
	abstract = {The continental slope off Cape Hatteras, NC is a region of high sediment accumulation and organic matter deposition. Sediment accumulation rates range from 3 to 151 cm kyr(-1). Organic carbon deposition rates are 5-13 moles C m(-2) yr(-1), the highest reported for the slope off the eastern US. Burial efficiencies are 3-40\%. The organic matter deposited is marine in origin and a mix of old and young particles. High organic carbon deposition rates support remineralization throughout the upper 2-3 m of sediment. Deep bioirrigation to depths of 60-100 cm within the seabed affects the biogeochemistry of the sediments by extending the zone of sulfate reduction and by steepening DIC porewater gradients through the non-local exchange of porewater. Stable and radiocarbon isotope mixing curves for porewater dissolved inorganic carbon (DIC) indicate that the dominant source of DIC accumulating in the upper 2-3 m of the seabed is of nearly uniform delta(13)C (-21.10parts per thousand) and Delta(14)C (-546parts per thousand.). (C) 2002 Elsevier Science Ltd. All rights reserved.},
	keywords = {anaerobic methane oxidation, early diagenesis, margin, marine-sediments, MATTER, middle-atlantic-bight, sea-floor, shelf, south, waters},
	isbn = {0967-0645},
	author = {Thomas, C. J. and Blair, N. E. and Alperin, M. J. and DeMaster, D. J. and Jahnke, R. A. and Martens, C. S. and Mayer, L.}
}
@conference {1606,
	title = {Deposition of Bomb C-14 in Continental Slope Sediments: Use of Radiocarbon in Understanding Benthic Food Web Dynamics},
	booktitle = {Aquatic Sciences Meeting, ASLO},
	year = {2001},
	note = {id: 1368},
	month = {2001},
	pages = {45},
	address = {Albuquerque, NM},
	author = {DeMaster, D. J. and Blair, N. E. and Smith, C. R. and Fornes, W. L. and Thomas, C. J. and Plaia, G.}
}
