@article {508, title = {Molecular and isotopic constraints on the sources of suspended particulate organic carbon on the northwestern Atlantic margin}, journal = {Deep-Sea Research Part I-Oceanographic Research Papers}, volume = {56}, year = {2009}, note = {id: 774; 471WJ Times Cited:1 Cited References Count:73Y}, pages = {1284-1297}, abstract = {The abundance, carbon isotopic composition (Delta C-14 and delta C-13), and lipid biomarker (alkenones and saturated fatty acids) distributions of suspended particulate organic matter were investigated at three stations centered on the 2000, 3000, and 3500 m isobaths over the New England slope in order to assess particulate carbon sources and dynamics in this highly productive and energetic region. Transmissometry profiles reveal that particle abundances exhibit considerable fine structure, with several distinct layers of elevated suspended particulate matter concentration at intermediate water depths in addition to the presence of a thick bottom nepheloid layer at each station. Excluding surface water samples, the Delta C-14 values of particulate organic carbon (POC) indicated the presence of a pre-aged component in the suspended POC pool (Delta C-14}, issn = {0967-0637}, doi = {10.1016/j.dsr.2009.01.012}, author = {Hwang, J. and Montlucon, D. and Eglinton, T. I.} } @article {1977, title = {Radiocarbon dating of alkenones from marine sediments: I. Isolation protocol}, journal = {Radiocarbon}, volume = {47}, year = {2005}, note = {993nkTimes Cited:13 Cited References Count:22 }, month = {2005}, pages = {401-412}, abstract = {The chemical and isotopic compositions of long-chain (C-36-C-39) unsaturated ketones (alkenones), a unique class of algal lipids, encode surface ocean properties useful for paleoceanographic reconstruction. Recently, we have sought to extend the utility of alkenones as oceanic tracers through measurement of their radiocarbon contents. Here. we describe a method for isolation of alkenones from sediments as a compound class based on a sequence of wet chemical techniques. The steps involved, which include silica gel column chromatography, urea adduction, and silver nitrate-silica gel column chromatography, exploit various structural attributes of the alkenones. Amounts of purified alkenones estimated by GC/FID measurements were highly correlated with CO2 yields after sample combustion, indicating purities of greater than 90\% for samples containing >= 100 mu g C. The degree of alkenone unsaturation (U-37(K{\textquoteright})) also varied minimally through the procedure. We also describe a high-performance liquid chromatography (HPLC) method to isolate individual alkenones for molecular-level structural and isotopic determination.}, keywords = {AMS, carbon, indicators, proxy, records, tool}, isbn = {0033-8222}, author = {Ohkouchi, N. and Xu, L. and Reddy, C. M. and Montlucon, D. and Eglinton, T. I.} } @article {1980, title = {Radiocarbon dating of alkenones from marine sediments: II. Assessment of carbon process blanks}, journal = {Radiocarbon}, volume = {47}, year = {2005}, note = {993nkTimes Cited:13 Cited References Count:20 }, month = {2005}, pages = {413-424}, abstract = {We evaluate potential process blanks associated with radiocarbon measurement of microgram to milligram quantities of alkenones at the National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) facility. Two strategies to constrain the contribution of blanks to alkenone C-14 dates were followed: 1) dating of samples of known age and 2) multiple measurements of identical samples. We show that the potential contamination associated with the procedure does not lead to a systematic bias of the results of alkenone dating to either younger or older ages. Our results indicate that alkenones record Delta(14)C of ambient DIC with an accuracy of approximately 10 parts per thousand. A conservative estimate of measurement precision is 17 parts per thousand for modern samples. Alkenone C-14 ages are expected to be reliable within 500 yr for samples younger than 10,500 C-14 yr.}, keywords = {c-14 ams, organic-compounds, records, samples, system, tool}, isbn = {0033-8222}, author = {Mollenhauer, G. and Montlucon, D. and Eglinton, T. I.} } @article {2121, title = {Composition, age, provenance of organic matter in N. W. African dust over the Atlantic Ocean}, journal = {Geochemistry, Geophysics, Geosystems G3}, volume = {3}, year = {2002}, note = {id: 611}, month = {2002}, author = {Eglinton, T. I. and Eglinton, G. and Dupont, L. and Montlucon, D. and Sholkovitz, E. and Reddy, C. M.} }