@article {2669,
	title = {The southern Gulf of Mexico: A baseline radiocarbon isoscape of surface sediments and isotopic excursions at depth},
	journal = {PLOS ONE},
	volume = {15},
	year = {2020},
	month = {Mar-04-2021},
	pages = {e0231678},
	abstract = {The southern Gulf of Mexico (sGoM) is home to an extensive oil recovery and development infrastructure. In addition, the basin harbors sites of submarine hydrocarbon seepage and receives terrestrial inputs from bordering rivers. We used stable carbon, nitrogen, and radiocarbon analyses of bulk sediment organic matter to define the current baseline isoscapes of surface sediments in the sGoM and determined which factors might influence them. These baseline surface isoscapes will be useful for accessing future environmental impacts. We also examined the region for influence of hydrocarbon deposition in the sedimentary record that might be associated with hydrocarbon recovery, spillage and seepage, as was found in the northern Gulf of Mexico (nGoM) following the Deepwater Horizon (DWH) oil spill in 2010. In 1979, the sGoM experienced a major oil spill, Ixtoc 1. Surface sediment δ13C values ranged from -22.4{\textperthousand} to -19.9{\textperthousand}, while Δ14C values ranged from -337.1{\textperthousand} to -69.2{\textperthousand}.
Sediment δ15N values ranged from 2.8{\textperthousand} to 7.2{\textperthousand}, while the \%C on a carbonate-free basis ranged in value of 0.65\% to 3.89\% and \%N ranged in value of 0.09\% to 0.49\%. Spatial trends for δ13C and Δ14C were driven by water depth and distance from the coastline, while spatial trends for δ15N were driven by location (latitude and longitude). Location and distance from the coastline were significantly correlated with \%C and \%N. At depth in two of twenty (10\%) core profiles, we found negative δ13C and Δ14C excursions from baseline values in bulk sedimentary organic material, consistent with either oil-residue deposition or terrestrial inputs, but likely the latter. We then used 210Pb dating on those two profiles to determine the time in which the excursion-containing horizons were deposited. Despite the large spill in 1979, no evidence of hydrocarbon residue remained in the sediments from this specific time period.},
	keywords = {Gulf of Mexico, hydrocarbons, Oil spills, Oils, Petroleum, Sediment},
	doi = {10.1371/journal.pone.023167810.1371},
	url = {https://www.ncbi.nlm.nih.gov/pubmed/32294128},
	author = {Bosman, Samantha H. and Schwing, Patrick T. and Larson, Rebekka A. and Wildermann, Natalie E. and Brooks, Gregg R. and Romero, Isabel C. and Sanchez-Cabeza, Joan-Albert and Ruiz-Fern{\'a}ndez, Ana Carolina and Machain-Castillo, Maria Luisa and Gracia, Adolfo and Escobar-Briones, Elva and Murawski, Steven A. and Hollander, David J. and Chanton, Jeffrey P.},
	editor = {Potter-McIntyre, Sally}
}
@article {2015,
	title = {Episodic methane release events from Last Glacial marginal sediments in the western North Pacific},
	journal = {Geochemistry Geophysics Geosystems},
	volume = {5},
	year = {2004},
	note = {849mvTimes Cited:13
Cited References Count:73
},
	month = {Aug 19},
	pages = {1525-2027},
	abstract = {[1] According to recent observations of anomalous bottom-simulating reflections (BSR),the northwest Pacific marginal sediments around Japan main islands bear large abundances of methane hydrate [Satoh, 2002]. During the Last Glacial, direct and indirect evidence accumulated from geochemical data suggests that methane episodically released from hydrate trapped in the seafloor sediments [ Dickens et al., 1995; Hinrichs et al., 2003; Kennett et al., 2000]. Here we show that marginal sediments from the western North Pacific contain a hopanoid 17alpha( H), 21beta(H)-hop-22(29)-ene ( diploptene) derived from the activity of methanotrophic bacteria in water column and/or surface sediment during a warming period (Interstadial 3) in the Last Glacial. The carbon isotopic compositions of diploptene range between - 41.0parts per thousand and - 27.9parts per thousand ( relative to PDB). In the horizon indicative of a contribution of methanotrophic bacteria, foraminiferal isotope signals were also found with highly depleted C-13 compositions of planktonic foraminifera ( similar to - 1.9parts per thousand, PDB) and benthic foraminifera ( similar to - 0.8parts per thousand, PDB), suggesting indirect records of enhanced incorporation of C-13-depleted CO2 formed by methanotrophic process that use C-12-enriched methane as their main source of carbon. From combined isotopic data of molecular ( diploptene) and foraminifera, the most prominent signal of methane release was detected in the sediments deposited around 25.4 cal. kyr BP ( similar to 100 year time span), corresponding to the Interstadial 3. This is the first evidence of methane hydrate instability in the open western North Pacific during the Last Glacial. Considering the glacial-interglacial hydrographic conditions in this region, the instability of methane hydrate may be modulated by intermediate water warming and/or the lowering of sea level. Our results suggest that the western North Pacific marginal regions may be a profound effect on rapid global warming climate changes during the Last Glacial.},
	keywords = {atmospheric composition and structure : geochemical cycles, atmospheric methane, carbon isotopes, carbon isotopic fractionation, climate-change, cold seeps, diploptene, Foraminifera, gas-hydrate, geochemistry : isotopic composition/chemistry, geochemistry : organic geochemistry, hydrocarbons, interglacial, intermediate water, methane hydrate, santa-barbara basin, sea sediments, subduction zone, western north pacific},
	isbn = {1525-2027},
	doi = {10.1029/2004GC000699},
	url = {http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2\&amp;SrcAuth=Alerting\&amp;SrcApp=Alerting\&amp;DestApp=WOS\&amp;DestLinkType=FullRecord;UT=WOS:000223543700001},
	author = {Uchida, M. and Shibata, Y. and Ohkushi, K. and Ahagon, N. and Hoshiba, M.}
}
@article {2122,
	title = {Stable chlorine and carbon isotopic compositions of selected semi-volatile organochlorine compounds},
	journal = {Organic Geochemistry},
	volume = {33},
	year = {2002},
	note = {545bnTimes Cited:41
Cited References Count:25
},
	month = {2002},
	pages = {437-444},
	abstract = {To assess whether the isotopic composition of semi-volatile organochlorine compounds (SVOCs) may be a useful tool, we measured the bulk delta(37)Cl and delta(13)C values of several pesticides and Aroclor mixtures from different suppliers. Overall, the delta(37)Cl and delta(13)C values ranged from -5.10 to + 1.22\% and -31.63 to -22.39\%, respectively. These values are narrower than the ranges observed previously for volatile organic contaminants (VOCs). In particular, the isotopic compositions of the Aroclor mixtures were very tightly constrained for both chlorine and carbon, We also observed that SVOCs synthesized from hexachlorocyclopentadiene had the most enriched delta(37)Cl values. These data provide a baseline for future work employing isotope ratios to study the environmental fate of SVOCs. (C) 2002 Elsevier Science Ltd. All rights reserved.},
	keywords = {aroclors, fractionation, hydrocarbons, intrinsic bioremediation, samples, solvents, trichloroethene},
	isbn = {0146-6380},
	author = {Drenzek, N. J. and Tarr, C. H. and Eglinton, T. I. and Heraty, L. J. and Sturchio, N. C. and Shiner, V. J. and Reddy, C. M.}
}
