Abstract:

Dissolved rare earth element data collected on four cruises in the vicinity of the Deepwater Horizon blowout. Cruises were in early May 2010, late May 2010, October 2010, and October 2011. This dataset includes dissolved rare earth elements (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu). This represents a reanalysis of samples previously analyzed for dissolved Fe, Mn, Ba, Co, and Cu. Those data are archived with GRIIDC (DOI: 10.7266/N7MS3QQ5) (Dissolved trace metal and ancillary data (including nutrients and dissolved oxygen) in the vicinity of the Deepwater Horizon blowout, May 2010-October 2011.)

Suggested Citation:

Shiller, Alan M.. 2017. Dissolved rare earth elements in the vicinity of the Deepwater Horizon blowout, May 2010-October 2011. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/N7CC0XQ6

Publications:

Shiller, A. M., Chan, E. W., Joung, D. J., Redmond, M. C., & Kessler, J. D. (2017). Light rare earth element depletion during Deepwater Horizon blowout methanotrophy. Scientific Reports, 7(1). doi:10.1038/s41598-017-11060-z

Purpose:

To examine the possibility that light rare earth elements (e.g., La, Ce, Pr, Nd) might have been removed by methanotrophy during the Deepwater Horizon blowout.

Data Parameters and Units:

Cruise, Station, Date (MM/DD/YYYY), Latitude (decimal degrees), Longitude (decimal degrees), Sample depth (m), Concentrations of dissolved (<0.45 µm) rare earth elements (pmol/kg), Sample ID (MM-YY-STN-SHIP)

Methods:

For analysis of dissolved rare earth elements (including Y), 7 mL of sample was spiked with a mixture of isotopically-enriched Nd-145, Sm-149, Eu-153, Gd-155, Dy-161, Er-167, and Yb-171 (Oak Ridge Nat'l. Labs). Each spike was >90% enriched in the listed isotopes. The sample/spike ratio was chosen so as to have the analytical isotope ratios approximately the geometric mean of the natural and enriched spike isotope ratios. Samples were then extracted/pre-concentrated using a SeaFAST system (Elemental Scientific, Inc.) operated in offline mode. A similar online SeaFAST extraction procedure is described by Hathorne et al., 2012. The extracted samples were subsequently analyzed using a Thermo-Fisher high resolution ICP-MS with an Apex-FAST high efficiency sample introduction system including a Spiro desolvator (Elemental Scientific, Inc.). The instrument was operated in low resolution. The enriched isotope spikes also served to provide counts/sec. calibration factors for elements that were not spiked with enriched isotopes. This calibration was also examined with a standard made in dilute nitric acid. Precision and recovery were checked by analysis of a large-volume composite North Atlantic surface seawater sample. Spiked (with a natural isotopic abundance elemental spike) and unspiked aliquots of this sample were analyzed twice in each analytical run. A Ba standard was also run to check for BaO+ interference on several isotopes and Ba in the extracted samples was also monitored. Because the extraction resin in the SeaFAST system (Nobias PA-1) discriminates against Ba, plus the reduction of the BaO+ interference by the desolvation system, BaO+ was less than 0.1% of the counts in Eu-151, Eu-153, Gd-155, and Gd-157. Tests also revealed no significant low REE oxide interference on mid-/high-REEs. Hathorne, E.C., B. Haley, T. Stichel, P. Grasse, M. Zieringer, and M. Frank, 2012. Online preconcentration ICP-MS analysis of rare earth elements in seawater. Geochemistry Geophysics Geosystems 13: Q01020. doi: 10.1029/2011GC003907.

Error Analysis:

Application of this analytical method to 14-mL sample aliquots from a profile collected at the Bermuda Atlantic Times Series station (BATS), yielded results equivalent to those previously published for that station by van de Flierdt et al. (2012), Pahnke et al. (2012), and Middag et al. (2015). Detection limits were typically <1% of the concentrations reported here except for Ce and Eu where detection limits were <5% of the reported concentrations. Precision (1σ) was typically ±2% and recoveries were typically 102 ± 3%. R. Middag, R. Seferian, T.M. Conway, S.G. John, K.W. Bruland, and H.J.W. de Baar, 2015. Intercomparison of dissolved trace elements at the Bermuda Atlantic Time Series station. Marine Chemistry 177: 476-489. doi: 10.1016/j.marchem.2015.06.014 K. Pahnke, T. van de Flierdt, K. Jones, S. R. Hemming, and S.L. Goldstein, 2012. GEOTRACES intercalibration of neodymium isotopes and rare earth element concentrations in seawater and particles—Part 2: systematic tests and baseline profiles. Limnol Oceanogr. Methods 10: 252-269. doi:10.4319/lom.2012.10.252 van de Flierdt, T. and others, 2012. GEOTRACES intercalibration of neodymium isotopes and rare earth elements in seawater and marine particulates. Part 1: international intercomparison. Limnol. Oceanogr. Methods 10: 234-251. doi:10.4319/lom.2012.10.234

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