Abstract:

This dataset contains sediment trap particulates isotopic composition from three stations. The DWH sediment trap site (Deep Water Horizon, also referred to as R/V Oceanus Site 26, or OC-26; 28°40'N, 88°21.6'W; 1660 m deep; 120 meters above the seafloor; and for some of the time, at 30 meters above the seafloor). The Seep site sediment was located near a large natural hydrocarbon seep, GC-600, (27°22.5’N, 90°30.6’W; 1380 m deep). The reference site was located is located in the Atwater Valley lease block and approximates a reference or background site (Reference site, (AT357, 27°31.5 N, 89°42.6 W; 1160 m deep). The data are organized by site, date (Month/day/year = M/D/Y) of the start of the collection period which lasted about 18 days, and by isotope. Three isotopes are reported, D14C, d13C and d34S.

Suggested Citation:

Jeff Chanton, Uta Passow. 2018. Isotopic composition of particulates from sediment trap, northern Gulf of Mexico, August 25, 2010 - March 18, 2016. Distributed by: Gulf of Mexico Research Initiative Information and Data Cooperative (GRIIDC), Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N737775J

Publications:

Diercks, A.-R., Dike, C., Asper, V. L., DiMarco, S. F., Chanton, J. P., & Passow, U. (2018). Scales of seafloor sediment resuspension in the northern Gulf of Mexico. Elem Sci Anth, 6(1), 32. doi:10.1525/elementa.285

Chanton, J. P., Giering, S., Bosman, S. H., Rogers, K. L., Sweet, J., Asper, V., … Passow, U. (2018). Isotopic composition of sinking particles: Oil effects, recovery and baselines in the Gulf of Mexico, 2010–2015. Elem Sci Anth, 6(1), 43. doi:10.1525/elementa.298

Chanton, J. P., Jaggi, A., Radović, J. R., Rosenheim, B. E., Walker, B. D., Larter, S. R., … Oldenburg, T. B. P. (2019). Mapping Isotopic and Dissolved Organic Matter Baselines in Waters and Sediments of the Gulf of Mexico. Scenarios and Responses to Future Deep Oil Spills, 160–181. doi:10.1007/978-3-030-12963-7_10

Purpose:

To gauge the recovery and post-spill baseline conditions in the northern Gulf of Mexico following the 2010 Deepwater Horizon (DWH) oil spill.

Data Parameters and Units:

Date (Month, Day, Year). D14C, d13C, d34S (parts per thousand). Results are presented relative to VPDB or CDT (δ13C or 34S = (Rsam/Rstd -1) X 1000, where R = 13C/12C or 34S/32S), Depth (m) Site Latitude (decimal degrees) Longitude (decimal degrees) OC26/DWH 28.666667 -88.36 GC600/Seep 27.375 -90.51 AT357/Reference 27.525 -89.71

Methods:

Prior to isotope analysis, sample splits were dried, ground, soaked briefly with 10% HCl to remove carbonates, rinsed with ultra pure water and freeze dried. Samples were then analyzed for δ 13C, Δ14C and δ34S. The δ13C was measured on a Carlo Erba elemental analyzer coupled to a Delta XP Thermo Finnegan isotope ratio mass spectrometer. Analytical reproducibility was on the order of 0.2 ‰. Stable sulfur isotopes (34S‰) were analyzed at the Stable Isotope Core Facility at Washington State University (Pullman, Washington). Analytical error measured as the coefficient of variation of replicate samples was 0.4‰ for δ34S. Results are presented relative to VPDB or CDT (δ13C or 34S = (Rsam/Rstd -1) X 1000, where R = 13C/12C or 34S/32S). Samples for ∆14C-POC analysis were combusted and purified CO2 prepared as graphite targets and analyzed by accelerator mass spectrometry [Vogel, J.S., Southron, J.R., Nelson, D.E., & Brown, T.A. (1984). Performance of catalytically condensed carbon for use in accelerator mass spectrometry. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms. 5(2): 289-293. doi: 10.1016/0168-583X(84)90529-9]. Values are reported according to the notation put forth in [Stuiver, M. & Polach, H.A. (1977). Discussion: Reporting of 14C Data. Radiocarbon. 19(3): 355-363]. The notation normalizes the radiocarbon content of a sample to a nominal δ13C value (-25‰) and the collection time. The scale is linear and starts at -1000‰ when a sample has essentially 0% modern carbon which would represent petroleum residue. Analytical reproducibility was on the order of 3 ‰. Samples were run on AMS facilities at Woods Hole Oceanographic Institution (NOSAMS) or the University of Georgia Center for Applied Isotope Studies. For all three isotopic scales, increases in values denote increases in the relative amount of the heavy isotope 13C, 14C or 34S. Conversely, decreases in or ∆) values denote depletion in the heavy isotope, 13C, 14C or 34S, relative to the standard material. Stuiver M & Polach HA (1977) Reporting Of 14C Data. Radiocarbon 19:355-263.

Instruments:

13C = Carlo Erba elemental analyzer coupled to a Delta XP Thermo Finnegan isotope ratio mass spectrometer. 14C = Samples were run on AMS facilities at Woods Hole Oceanographic Institution (NOSAMS) or the University of Georgia Center for Applied Isotope Studies. d34S = Stable Isotope Core Facility at Washington State University (Pullman, Washington).

Error Analysis:

see methods

Individual Files: