Globorotalia truncatulinoides Trace Element Geochemistry (Barium, Magnesium, Strontium, Manganese, and Calcium) from the Gulf of Mexico Sediment Trap

Metadata also available as - [Outline] - [Parseable text] - [XML]

Frequently anticipated questions:

What does this data set describe?

Globorotalia truncatulinoides Trace Element Geochemistry (Barium, Magnesium, Strontium, Manganese, and Calcium) from the Gulf of Mexico Sediment Trap
Observations of elevated barium-to-calcium ratio (Ba/Ca) in Globorotalia truncatulinoides have been attributed to contaminant phases, deep calcification depth and diagenetic processes. U.S. Geological Survey (USGS) scientists and their collaborators investigated intra- and inter-test Ba/Ca variability in the non-spinose planktic foraminifer, G. truncatulinoides, from a sediment trap time series (2009-2017) in the northern Gulf of Mexico (generally 27.5°N and 90.3°W) to gain insights into the environmental influences on barium enrichment in this and other non-spinose species. Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was used to differentiate between the elemental composition of the crust and lamellar calcite in non-encrusted (< 150 meters [m] calcification depth) and encrusted (> 250 meters calcification depth) specimens of G. truncatulinoides. For further information regarding data collection, processing methods, and/or results and interpretive study refer to Richey and others (2022).
Field Activity Numbers (FANs) are unique identifiers assigned by the USGS to provide more information about the activities conducted in the field for a study. Please visit the Coastal and Marine Geoscience Data System (CMGDS) field activity webpage for more information about each FAN related to this dataset. To view field activity details for any of the datasets included in this data release, replace the FAN (09CEV02) in the following url with the FAN of interest (for example, 10CEV01):
  1. How might this data set be cited?
    Reynolds, Caitlin E., Richey, Julie N., Fehrenbacher, Jennifer S., Davis, Catherine V., and Spero, Howard J., 20220719, Globorotalia truncatulinoides Trace Element Geochemistry (Barium, Magnesium, Strontium, Manganese, and Calcium) from the Gulf of Mexico Sediment Trap:.

    This is part of the following larger work.

    Reynolds, Caitlin E., Richey, Julie N., Fehrenbacher, Jennifer S., Davis, Catherine V., and Spero, Howard J., 20220719, Globorotalia truncatulinoides Trace Element Geochemistry (Barium, Magnesium, Strontium, Manganese, and Calcium) From the Gulf of Mexico Sediment Trap: U.S. Geological Survey data release doi:10.5066/P9YQMIH5, U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center, St. Petersburg, Florida.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -90.49
    East_Bounding_Coordinate: -90.30
    North_Bounding_Coordinate: 28.38
    South_Bounding_Coordinate: 27.50
    Description_of_Geographic_Extent: northern Gulf of Mexico
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 2009
    Ending_Date: 2017
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: tabular digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a Point data set.
    2. What coordinate system is used to represent geographic features?
  7. How does the data set describe geographic features?
    Detailed entity and attribute descriptions for all the data files (.xlsx and .csv) included in this data release (Reynolds and others, 2022) are detailed in a Data Dictionary (Data_Dictionary_Trace_Element_Geochemistry.docx). A copy of the Data Dictionary is included in each of the data zip files. These metadata are not complete without this file, and users should refer to the Data Dictionary when viewing the data files.
    Reynolds, C.E., Richey, J.N., Fehrenbacher, J.S., Davis, C.V., and Spero, H.J., 2022, Globorotalia truncatulinoides trace element geochemistry (barium, magnesium, strontium, manganese, and calcium) from the Gulf of Mexico sediment trap: U.S. Geological Survey data release,
  8. What biological taxa does this data set concern?
    Taxonomic_Keyword_Thesaurus: USGS Biocomplexity Thesaurus
    Taxonomic_Keywords: Protists
    Originator: Integrated Taxonomic Information System (ITIS)
    Publication_Date: 2022
    Title: Integrated Taxonomic Information System (ITIS)
    Geospatial_Data_Presentation_Form: ONLINE_REFERENCE
    Publication_Place: Washington, D.C.
    Publisher: Integrated Taxonomic Information System (ITIS)
    Contact_Person: Caitlin E. Reynolds
    Contact_Organization: Southeast Region: ST. PETE COASTAL & MARINE SC
    Contact_Position: Geologist
    Address_Type: mailing and physical
    Address: 600 4Th Street South
    City: St. Petersburg
    State_or_Province: FL
    Postal_Code: 33701
    Country: US
    Contact_Voice_Telephone: 727-502-8046
    Taxonomic_Procedures: expert advice;;identification keys;;specimen processing
    All planktic foraminifera were collected and identified under the microscope by trained scientists. No ambiguous individuals were used to ensure correct species identification.
    General_Taxonomic_Coverage: Planktic foraminifera were collected and identified to species.
    Taxon_Rank_Name: Kingdom
    Taxon_Rank_Value: Protozoa
    Taxon_Rank_Name: Phylum
    Taxon_Rank_Value: Protozoa
    Taxon_Rank_Name: Subphylum
    Taxon_Rank_Value: Sarcodina
    Taxon_Rank_Name: Superclass
    Taxon_Rank_Value: Rhizopoda
    Taxon_Rank_Name: Class
    Taxon_Rank_Value: Granuloreticulosea
    Taxon_Rank_Name: Order
    Taxon_Rank_Value: Foraminiferida
    Taxon_Rank_Name: Suborder
    Taxon_Rank_Value: Rotaliina
    Taxon_Rank_Name: Superfamily
    Taxon_Rank_Value: Globigerinoidea
    Taxon_Rank_Name: Family
    Taxon_Rank_Value: Globorotaliidae
    Taxon_Rank_Name: Subfamily
    Taxon_Rank_Value: Globorotaliinae
    Taxon_Rank_Name: Genus
    Taxon_Rank_Value: Globorotalia

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Reynolds, Caitlin E.
    • Richey, Julie N.
    • Fehrenbacher, Jennifer S.
    • Davis, Catherine V.
    • Spero, Howard J.
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    Caitlin E. Reynolds
    Southeast Region: ST. PETE COASTAL & MARINE SC
    600 4Th Street South
    St. Petersburg, FL

    727-502-8046 (voice)

Why was the data set created?

The barium-to-calcium ratio (Ba/Ca) of planktic foraminifera has been used to track changes in freshwater flux to near-shore depositional sites over time and thus may be a powerful proxy for reconstructing past changes in the hydrologic cycle. This study investigated the intra- and inter-test Ba/Ca variability in G. truncatulinoides specimens from a sediment trap deployed in the northern Gulf of Mexico to better understand the environmental controls on barium incorporation into this and other non-spinose foraminifera.

How was the data set created?

  1. What methods were used to collect the data?
    Method 0 of 1
    Type: field and laboratory
    All foraminifera analyzed in this study were collected using a McLane PARFLUX Mark 78 automated sediment trap initially deployed in January 2008 (FAN: 08CEV01) in 1,150 meters (m) of water in the northern Gulf of Mexico (27.5°N and 90.3°W). The trap was positioned at a depth of 700 m on the mooring cable to enable the collection of deeper dwelling species of planktic foraminifera. Details of the sediment trap sampling methods can be found in Reynolds and Richey (2016). One hundred and thirty-four Globorotalia truncatulinoides specimens were picked based on availability from January 2010–March 2014. Forty encrusted specimens were selected from winter (January–April), and 94 non-encrusted specimens from throughout the seasonal cycle. The magnesium-to-calcium ratio (Mg/Ca), delta oxygen-18 (δ18O), and delta carbon-13 (δ13C) data for these 134 individual G. truncatulinoides specimens were previously published in Reynolds and others (2018). Whole shells of foraminifers were cleaned according to modified procedures for laser ablation (Vetter and others, 2013; Fehrenbacher and others, 2015). Briefly, samples were cleaned by ultrasonication in methanol followed by triple-rinsing in Milli-Q water (18.2 megohm-centimeter [MΩ-cm]). Shells were then oxidatively cleaned at 60 °Celsius (C) for 30 min in buffered hydrogen peroxide (H2O2, 1:1 mix of 30% hydrogen peroxide and 0.1 N sodium hydroxide [NaOH]) to remove remnant organic matter. Finally, the shells were triple rinsed in Milli-Q water. Because there is a continuum between the completely encrusted and non-encrusted forms of G. truncatulinoides, visual discrimination between the two forms can be somewhat subjective under a binocular microscope. Reynolds and others (2018) demonstrated that the length-weight relationship could be used to distinguish between encrusted and non-encrusted G. truncatulinoides when a visual distinction is ambiguous. Individual O. universa (sample size, n=64) were picked from the same sediment trap cups as G. truncatulinoides samples for individual foraminiferal laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). A suite of additional samples from a total of 8 planktic species (Globigerinoides ruber pink, Globigerinoides ruber white, Globorotalia truncatulinoides, Neogloboquadrina dutertrei, Globorotalia menardii, Globorotalia tumida, Pulleniatina obliquiloculata, and Orbulina universa) were picked for elemental analysis via solution-based ICP-MS. Foraminifera were picked from samples collected in 2017, and the researchers aimed to sample all parts of the seasonal cycle when enough foraminifera were available. Reference:
  2. From what previous works were the data drawn?
  3. How were the data generated, processed, and modified?
    Date: 2016 (process 1 of 3)
    LA-ICP-MS: Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) on G. truncatulinoides specimens was conducted at The University of California, Davis Stable Isotope Laboratory, using a Photon Machines 193 nanometer (nm) ArF ultraviolet (UV) excimer laser with an ANU HelEx dual-volume laser ablation cell coupled to an Agilent 7700× quadrupole-ICP-MS, please see Data_Dictionary_Trace_Element_Geochemistry.docx for instrument setting details. The G. truncatulinoides shells were placed on double sided carbon tape spiral side up to ensure a horizontal sampling surface for each chamber. Laser spot size of 44 × 44 micrometers (μm) in diameter was used with a repetition rate of 6 hertz, Hz, (non-encrusted forms) and 8 Hz (encrusted forms). Due to the thickness of the calcite, a higher repetition rate was needed to ablate through the encrusted shells. For the smallest foraminifers, the spot size was decreased to 30 × 30 μm to ensure ablation within a single chamber. Masses measured included magnesium-24 (24Mg), magnesium-25 (25Mg), aluminimum-27 (27Al), calcium-44 (44Ca), manganese-55 (55Mn), strontium-88 (88Sr), yttrium-89 (89Y), and barium-138 (138Ba). Standard reference materials from the National Institute of Standards and Technology (SRM NIST) 610, 612, and 614 glass standards were run before and after each batch of samples as an external standard. An O. universa shell, which is demonstrated to have highly reproducible trace element (TE) profiles throughout, was analyzed before and after each run as an internal working standard (7.0 ± 0.7 millimoles per mole [mmol/mol] Mg/Ca, 2 standard deviations [σ], Fehrenbacher and others, 2015). Outliers in the TE/Ca (trace element/calcium) profiles that were greater than ± 6 standard deviations from a 3-point rolling mean were removed from raw LA-ICP-MS signals, then data were reduced using Iolite Software (Paton and others, 2011). Depth profiles were analyzed on each chamber (F–F2 for every specimen, and up to F7 for select specimens). If chambers were large enough, we analyzed up to 3 repeat spots to assess reproducibility and data quality assurance and quality control (QA/QC). The pooled standard deviation among replicate spots was 0.44 micromoles per mole, μmol/mol, (n=71) for encrusted and 1.24 μmol/mol (n=270) in non-encrusted specimens. Individual O. universa specimens were analyzed via LA-CIP-MS at Oregon State University using a Teledyne/Photon Machines 193 nm ArF UV excimer laser ablation system with a HelEx laser ablation cell coupled to a Thermo Scientific X-series II quadrupole ICP-MS, please see Data_Dictionary_Trace_Element_Geochemistry.docx for instrument setting details. Gas composition and flow rate were determined by adjusting the flow of argon (Ar) and helium (He) as necessary to achieve high count rates on the sample/standard while maintaining ThO+/Th+ ratios less than 0.2% (tuned daily). Shell fragments were analyzed from the inside - out. Samples were analyzed using a 50–70 μm diameter spot size at 5 Hz repetition rate and 1.0–1.5 joules per square centimeter (J/cm2) laser fluence. Data acquisition varied between 20–60 seconds (s) per spot analysis. Masses measured included 24Mg, 25Mg, 27Al, 43Ca, 44Ca, 55Mn, 78Sr, 88Sr, 138Ba, and uranium-238 (238U). 43Ca was used as the internal standard and 44Ca was monitored for consistency. Dwell times varied by analyte and ranged from 0.20–0.5 milliseconds (ms). Individual mean elemental concentrations were calculated using Iolite Software (Paton and others, 2011). The mean TE/Ca ratio for each profile was then calculated by normalizing to the known TE concentration in the drift/background-corrected bracketed analyses of the NIST SRM 610 and 612 glass standards at 5 Hz and approximately 4.5 J/cm2 laser fluence (Jochum and others, 2011).
    Date: 2019 (process 2 of 3)
    Trace Metal Analysis in Seawater: The Ba, Sr, and Ca concentrations were measured in seawater samples collected from the sediment trap site from the surface to 1100 meters water depth in July 2018 and February 2019. Additional water sampling was carried out on the July 2018 cruise at 2 nearshore sites on the Louisiana shelf in 17 meters water depth (28.87°N, 90.49°W) and 50 meters water depth (28.38°N, 90.47°W). All water samples were collected in a Niskin water sampling rosette, filtered through acid-cleaned Millex® PVDF (0.45 μm pore size) membrane filters into acid-leached 50 milliliter (mL) centrifuge tubes, and acidified with 25 microliters (μl) Optima grade concentrated nitric acid (HNO3). Seawater was diluted 10-fold with 2% nitric acid, spiked with an internal standard containing beryllium (Be), scandium (Sc), Y, and indium (In) to correct for instrumental drift, and analyzed using an Agilent 7500cx ICP-MS equipped with a High Matrix Introduction accessory, which uses aerosol dilution to reduce matrix effects, and an octopole reaction cell, which uses helium gas to reduce polyatomic interferences (Wilschefski and Baxter, 2019). Samples were analyzed for Sr in ultra-robust mode and in the presence of helium, and for Ca and Ba in robust mode and the absence of helium. Two external six-point calibration curves, one for elements with concentrations in the ppm range (sodium [Na], Mg, Ca) and one for elements with concentrations in the ppb range (lithium [Li], Mn, Sr, Ba), were analyzed before and after samples. Individual elemental standards were obtained from SPEX CertiPrep (Metuchen, New Jersey).
    Date: 2016 (process 3 of 3)
    Solution Based ICP-MS: The 49 solution-based G. ruber (pink and white) analyses from the 2010 sediment trap samples were cleaned according to the Barker and others (2003) procedure in a laminar flow clean bench and analyzed for Mg/Ca and Ba/Ca using inductively coupled plasma mass spectrometry at Texas A&M, College Station, Texas, United States of America, on a Thermo Scientific Element XR High Resolution ICP-MS. The corresponding Mg/Ca data are published in Richey and others (2022). (2019). All other solution-based trace element analyses (for example, G. truncatulinoides, O. universa, G. menardii, P. obliquiloculata, G. tumida, N. dutertrei and G. ruber collected from 2018 sediment trap samples) were carried out using a Thermo Finnegan Element 2 in the Center for Elemental Mass Spectrometry at the University of South Carolina. Foraminifers were crushed gently in a microcentrifuge tube and cleaned as samples for laser analyses in a 1:1 mixture of H2O2 and NaOH in a warm water bath (approximately 65 °C) for 10 minutes, during which samples were sonicated 4 times for 10s. Samples prepared for solution analyses were dissolved in 1% nitric acid and then diluted in a matrix of 2% nitric acid to a consistent concentration of 20 parts per million (ppm) Ca. Dissolved samples were run along with in house standard solutions, each containing 20 ppm Ca and varying concentrations of other analytes including 25Mg, 43Ca, 55Mn, 87Sr, 137Ba, and 238U.
  4. What similar or related data should the user be aware of?

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    All attribute values were determined to be accurate, please refer to the Process Steps of this metadata record for more information.
  2. How accurate are the geographic locations?
    The geographic location of the sediment trap and seawater samples were obtained using a Global Positioning System (GPS) aboard a research vessel. A formal accuracy assessment of the horizontal positional information in the data set has not been conducted or is unknown.
  3. How accurate are the heights or depths?
    A formal accuracy assessment of the vertical positional information in the data set has not been conducted or is unknown.
  4. Where are the gaps in the data? What is missing?
    Data set is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details.
  5. How consistent are the relationships among the observations, including topology?
    All attribute values were determined to be accurate, please refer to the Process Steps of this metadata record for more information.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints None
Use_Constraints None
  1. Who distributes the data set? (Distributor 1 of 1)
    Caitlin E. Reynolds
    Southeast Region: ST. PETE COASTAL & MARINE SC
    600 4Th Street South
    St. Petersburg, FL

    727-502-8046 (voice)
  2. What's the catalog number I need to order this data set?
  3. What legal disclaimers am I supposed to read?
    Although these data have been processed successfully on a computer system at the U.S. Geological Survey, no warranty expressed or implied is made regarding the display or utility of the data on any other system, or for general or scientific purposes, nor shall the act of distribution imply any such warranty. The U.S. Geological Survey shall not be held liable for improper or incorrect use of the data described and (or) contained herein. Any use of trade, firm, or product name is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?

Who wrote the metadata?

Last modified: 19-Jul-2022
Metadata author:
Caitlin E. Reynolds
Southeast Region: ST. PETE COASTAL & MARINE SC
600 4Th Street South
St. Petersburg, FL

727-502-8046 (voice)
Metadata standard:
FGDC Biological Data Profile of the Content Standard for Digital Geospatial Metadata (FGDC-STD-001.1-1999)

This page is <>
Generated by mp version 2.9.51 on Tue Jul 19 16:36:01 2022