2008-2017 Globigerinoides ruber Sediment Trap Data Collected from the Gulf of Mexico

From 2008 to 2017, USGS staff conducted 17 surveys within the Gulf of Mexico, onboard the research vessel (R/V) Pelican, to collect sediment trap and seawater samples that would allow researchers to 1) evaluate the performance of previously-published equations for calculating SST, SSS and isotopic composition, and 2) determine linear relationships between salinity and d18Osw for the water column and surface mixed layer. All data were processed between 2008 and 2018. For elemental analyses, 30–60 foraminifera from the 212–425 micrometer (um) size fraction were lightly crushed, homogenized, and cleaned according to a modified version of the Barker and others (2003) protocol. Briefly, the cleaning procedure included two Milli-Q water rinses, two methanol rinses, an oxidation step with a modified buffered hydrogen peroxide (H2O2) solution following Russell and others (2004) for recently living foraminifer (1:1 solution of 0.1 normal sodium hydroxide [N NaOH] and 30% H2O2), and a dilute acid leach (0.001 molar solution [M] nitric acid). A reductive cleaning step was not performed, as these foraminifers were not subject to diagenetic Iron-Manganese (Fe-Mn) oxide coatings often found on foraminifera from sediment cores. Cleaned foraminiferal samples collected from 2011–2013 were dissolved in nitric acid to achieve a target calcium concentration of 20 parts per million (ppm). Acidified samples were analyzed on a PerkinElmer 7300 DV inductively coupled plasma optical emission spectrometer (ICP-OES) at the USGS St. Petersburg Coastal and Marine Science Center, FL, USA. Mg/Ca was corrected for instrumental drift using the internal gravimetric standard (IGS) method devised by Schrag (1999). The average corrected IGS precision for Mg/Ca was 0.024 millimoles per mole (mmol/mol-1) (1σ, n = 1315). A calcium carbonate (CaCO3) standard (homogenized powder of ECRM-751) analyzed for Mg/Ca was used to test for any potential matrix effects, it had an average corrected precision of 0.096 mmol/mol-1 (1σ, n = 123). Researchers analyzed the JCt-1 standard used in an inter-laboratory comparison study of Mg/Ca and determined an average Mg/Ca was 1.228 ± 0.037 mmol/mol-1 (n = 10, 1σ). Samples from 2010 were cleaned according to the Barker and others (2003) procedure in a laminar flow clean bench and analyzed for Mg/Ca and Barium/Calcium (Ba/Ca), using inductively coupled plasma mass spectrometry (ICP-MS) at Texas A&M, College Station, Texas, USA on a Thermo Scientific Element XR High Resolution ICP-MS. Carbon and oxygen isotopic analyses were performed on aliquots of 6–8 whole foraminifera shells (212–425 um), on a Thermo-Finnigan MAT 253 isotope ratio mass spectrometer coupled to a Kiel IV Carbonate Device housed in the Analytical Laboratory for Paleoclimate Studies (ALPS) at the Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, USA. The 1s precision of stable isotopic measurements in this study were based on multiple analyses of an in-house carbonate standard (n = 24) and equaled 0.03‰ for d13C and 0.06‰ for d18O, consistent with long-term precision for this instrumental set-up (0.06‰ for d13C and 0.08‰ for d18O). All stable isotope values are reported relative to Vienna Pee Dee Belemnite (VPDB). Seawater samples were collected from Niskin bottles during CTD casts on research cruises to deploy and recover the sediment trap. Seawater was sampled immediately following sediment collection and sealed in crimp top glass vials. The oxygen isotopic composition of seawater was measured on a Gasbench coupled to a MAT 253 isotope ratio mass spectrometer at the University of Texas at Austin, Austin, Texas, USA, where the long-term precision of replicate measurements of an in-house standard was 0.12 ‰ and 2 ‰ for d18O and d2H, respectively (2σ). Samples collected after 2010 were analyzed for both hydrogen (d2H) and oxygen (d18O) composition on a Picarro L2130-I Isotopic Liquid Water Analyzer (Picarro, Inc. Santa Clara, CA) at the University of Texas at Austin, Austin, Texas, USA. All isotopic values are given relative to Vienna Standard Mean Ocean Water (VSMOW). The long-term precision of replicate measurements of an in-house standard on the Picarro L2130-I was 0.13 ‰ and 0.59 ‰ for d18O and d2H, respectively.

Level 5 revision: The G. ruber flux dataset (G_ruber_Flux.csv) were withdrawn from this data release in September 2023. The sediment trap foraminifera flux data were incorrectly calculated per 0.5 meter-squared area instead of 1 meter-squared in the original version. Corrected data has been provided in a new data release, https://doi.org/10.5066/P9O76R8R (Reynolds and Richey, 2023). Please refer to that data release and its associated metadata for more information.