Globorotalia truncatulinoides Sediment Trap Data in the Gulf of Mexico

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Frequently anticipated questions:


What does this data set describe?

Title:
Globorotalia truncatulinoides Sediment Trap Data in the Gulf of Mexico
Abstract:
Modern observations of planktic foraminifera from sediment trap studies help to constrain the regional ecology of paleoceanographically valuable species. Results from a weekly-resolved sediment trap time series (2008–2014) in the northern Gulf of Mexico demonstrate that 92% of Globorotalia truncatulinoides flux occurs in winter (January, February, and March), and that encrusted and non-encrusted individuals represent calcification in distinct depth habitats. Individual foraminiferal analysis (IFA) of G. truncatulinoides tests were used to investigate differences in the elemental Magnesium/Calcium (Mg/Ca) and isotopic composition (δ18O and δ13C) of the encrusted and non-encrusted ontogenetic forms of G. truncatulinoides, and to estimate their calcification depth in the northern Gulf of Mexico. Estimates show that non-encrusted and encrusted G. truncatulinoides have mean calcification depths of 66 ± 9 meters and 393 ± 83 meters, respectively. The Mg/Ca-calcification temperature relationship was validated for G. truncatulinoides and demonstrated that the δ18O and Mg/Ca of the non-encrusted form is a suitable proxy for winter surface mixed layer conditions in the Gulf of Mexico. Care should be taken not to combine encrusted and non-encrusted individuals of G. truncatulinoides for down core paleoceanographic studies.
Supplemental_Information:
To ensure that USGS-St. Petersburg data management protocols were followed, each survey was assigned the following USGS FAN: 08CEV01–08CEV04, 09CEV01, 09CEV02, 10CEV01, 10CEV04, 11CEV01, 11CEV03, 12CEV01, 12CEV02, 13CEV01, and 13CEV03. Additional survey and data details are available from the U.S. Geological Survey Coastal and Marine Geoscience Data System (CMGDS) at, https://cmgds.marine.usgs.gov/.
  1. How might this data set be cited?
    Reynolds, Caitlin, 20180406, Globorotalia truncatulinoides Sediment Trap Data in the Gulf of Mexico: U.S. Geological Survey Data Release doi:10.5066/F72806W4, 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: -90.3
    East_Bounding_Coordinate: -90.3
    North_Bounding_Coordinate: 27.5
    South_Bounding_Coordinate: 27.5
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 18-Jan-2008
    Ending_Date: 25-May-2014
    Currentness_Reference:
    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?
    2. What coordinate system is used to represent geographic features?
  7. How does the data set describe geographic features?
    Isotopes.csv
    Individual foraminiferal analysis (IFA) was used to investigate the isotopic composition of the encrusted and non-encrusted ontogenetic forms of G. truncatulinoides collected between October 2009 and May 2014. Values obtained from the measurement of the ratio of stable isotopes oxygen-18 (d18O), oxygen-16 (d16O), carbon-13 (d13C) and carbon-12 (d12C) are included in this table. (Source: USGS)
    Sample Name
    Sediment Trap Sample identification (Source: USGS) The naming convention used to identify each foraminifera sample is as follows: xx-y-NCz, where xx refers to the Gulf of Mexico sediment trap cruise number; xx is between 6 and 14. The 1- or 2-digit integer, y, represents the sediment trap cup number, values range from 1 to 20. The last value, NCz (NC1–NC8), refers to encrusted (C) G. truncatulinoides or non-encrusted (NC) G. truncatulinoides and its individual foraminifera number (z).
    d13C (per mil relative to VPDB)
    Isotopic signature of 13C:12C, reported in parts per thousand relative to the Vienna Pee Dee Belemnite (VPDB). (Source: USGS)
    Range of values
    Minimum:-1.11
    Maximum:0.91
    d18O (per mil relative to VPDB)
    Isotopic signature of 18O:16O, reported in parts per thousand relative to the Vienna Pee Dee Belemnite (VPDB). (Source: USGS)
    Range of values
    Minimum:-1.13
    Maximum:1.59
    Mg_Ca_Compiled_all.csv
    Individual foraminiferal analysis (IFA) was used to investigate the elemental Magnesium/Calcium (Mg/Ca) composition of the encrusted and non-encrusted ontogenetic forms of G. truncatulinoides. Laser ablation (LA-ICP-MS) Mg and Ca values for every measurement on individual foraminifera are included in this comma separated values (CSV) file. Blank cells indicate no Mg ppm (m24), Ca ppm (m44), and Mg/Ca (mmol/mol) data was recorded. (Source: USGS)
    FAN
    The U.S. Geological Survey St. Petersburg Coastal and Marine Science Center assigns a unique identifier, known as a field activity number (FAN), to each field survey or cruise. (Source: USGS) The naming convention used for each field activity number. Each cruise number (6-14) uses a different FAN number.
    Sample Name
    Unknown (Source: USGS) The naming convention used to identify each foraminifera sample is as follows: xx-y-NCz, where xx refers to the Gulf of Mexico sediment trap cruise number; xx is between 6 and 14. The 1- or 2-digit integer, y, represents the sediment trap cup number, values range from 1 to 20. The last value, NCz (NC1–NC8), refers to encrusted (C) G. truncatulinoides or non-encrusted (NC) G. truncatulinoides and its individual foraminifera number (z).
    Chamber
    Unknown (Source: USGS) The first value (F0) refers to the chamber number (F0-F7) ablated on each individual foraminifera. The second value (IntegrationNo) refers to the automatic naming from the instrumentation output.
    Elapsed Time (s)
    Time in seconds (Source: USGS)
    Range of values
    Minimum:0
    Maximum:273.256
    Mg ppm (m24)
    Measured Magnesium in parts per million. (Source: USGS)
    Range of values
    Minimum:70.36339
    Maximum:15429.42
    Ca ppm (m44)
    Measured Calcium in part per million. (Source: USGS)
    Range of values
    Minimum:182514
    Maximum:1336423
    Mg/Ca (mmol/mol)
    This calculation is based on the following equation Mg/Ca (mmol/mol) =Mg ppm(m24)/Ca ppm(m44)*(40.078/24.305)*1000 (Source: USGS)
    Range of values
    Minimum:0.300415105
    Maximum:81.90071251
    Mg_Ca_Compiled_averages.csv
    This CSV file contains laser ablation (LA-ICP-MS) Mg and Ca values for every measurement averaged for each chamber on the individual foraminifera. (Source: USGS)
    Output
    Refers to the automatic naming from the instrumentation output. (Source: USGS) The first type (Output_1_x) refers to the output file from each spot ablated, the x ranges from 1-207. The second type (G_NIST610_y) refers to a standard that was run before and after all samples, the y values range from 1-4.
    Sample Name
    Sediment trap sample identification. (Source: USGS) The naming convention used to identify each foraminifera sample is as follows: xx-yNCz, where xx refers to the Gulf of Mexico sediment trap cruise number; xx is between 6 and 14. The 1- or 2-digit integer, y, represents the sediment trap cup number, values range from 1 to 20. The last value, NCz (NC1–NC4), refers to encrusted (C) G. truncatulinoides or non-encrusted (NC) G. truncatulinoides and its individual foraminifera number (z). There is an automatic instrumentation naming convention from the source file after each sample name, _A.D, _B.D, or _C.D.
    Duration(s)
    Time in seconds (s). (Source: USGS)
    Range of values
    Minimum:3.3071
    Maximum:273.48
    Mg_ppm_m24
    Measured Magnesium in parts per million. (Source: USGS)
    Range of values
    Minimum:198.4
    Maximum:5290
    Ca_ppm_m44
    Measured Calcium in parts per million. (Source: USGS)
    Range of values
    Minimum:366000
    Maximum:437000
    Mg/Ca (mmol/mol)
    This calculation is based on the following equation Mg/Ca (mmol/mol) =Mg ppm(m24)/Ca ppm(m44)*(40.078/24.305)*1000 (Source: USGS)
    Range of values
    Minimum:0.784541693
    Maximum:21.53828227
    Raw Counts and Flux Data.csv
    G. truncatulinoides raw counts and flux. (Source: USGS)
    FAN
    The U.S. Geological Survey St. Petersburg Coastal and Marine Science Center assigns a unique identifier, known as a field activity number (FAN), to each field survey or cruise. (Source: USGS) The naming convention used for each field activity number. Each cruise number (6-14) uses a different FAN number.
    Cruise
    Sediment Trap cruise number. (Source: USGS) Refers to the Gulf of Mexico Sediment Trap cruise number GMT-xx, xx ranges from 1-14.
    Cup
    Sediment trap cup number. (Source: USGS)
    Range of values
    Minimum:1
    Maximum:21
    Mid-week Date
    The mid-week date of the sediment trap sample collection. (Source: USGS)
    Range of values
    Minimum:January 18, 2008
    Maximum:May 25, 2014
    Raw Count (number)
    Total number of individual G. truncatulinoides. (Source: USGS)
    Range of values
    Minimum:1
    Maximum:1873
    Flux (tests m-2day-1)
    Flux is calculated by the following equation = (total number of individual foraminifera * split multiplier) / number of days sediment trap cup was open. (Source: USGS)
    Range of values
    Minimum:0
    Maximum:932.35
    Entity_and_Attribute_Overview:
    The entity and attribute information provided here describes the tabular data associated with the dataset. Please review the detailed descriptions that are provided (the individual attribute descriptions) for information on the values that appear as fields/table entries of the data et.
    Entity_and_Attribute_Detail_Citation:
    The entity and attribute information were generated by the individual and/or agency identified as the originator of the dataset. Please review the rest of the metadata record for additional details and information.

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Caitlin Reynolds
  2. Who also contributed to the data set?
    U.S. Geological Survey, Coastal and Marine Geology Program, St. Petersburg Coastal and Marine Science Center
  3. To whom should users address questions about the data?

Why was the data set created?

This information was used to (1) validate the Mg/Ca-calcification temperature relationship for G. truncatulinoides, (2) demonstrate that the non-encrusted form calcifies in the surface mixed layer, while the crust forms well below the seasonal thermocline, and (3) demonstrate that Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) analyses of single foraminifera can be used to yield comparable elemental ratios to that obtained from solution-based analyses.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 22-Apr-2016 (process 1 of 1)
    134 encrusted (C) and non-encrusted (NC) G. truncatulinoides specimens were picked based on availability from January 2010 through March 2014. Whole shell G. truncatulinoides were cleaned according to modified procedures for laser ablation (Vetter and others, 2013; Fehrenbacher and others, 2015). Samples were cleaned by ultrasonicating in methanol followed by triple-rinsing in Milli-Q water (18.2 MΩ cm). Shells were then oxidatively cleaned at 60°C for 30 minutes in a buffered hydrogen peroxide solution (1:1 mix of 30% hydrogen peroxide and 0.1N NaOH) to remove remnant organic matter. Finally, the shells were again triple rinsed in Milli-Q water. Once dry, each individual's length was measured across the diameter of the umbilical side, from the tip of the final chamber to the opposite side and weighed on a microbalance. 1 error on length measurements (± 16 µm) and weight measurements (± 0.6 µg) are based on repeated measurements by separate analysts. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) was conducted at The University of California, Davis Stable Isotope Laboratory, using Photon Machines 193 nm ArF UV excimer laser with an ANU HelEx dual-volume laser ablation cell coupled to an Agilent 7700x quadrupole-ICP-MS. G. truncatulinoides specimens were placed on double sided carbon tape, spiral side up, to ensure a horizontal sampling surface for each chamber. Laser spot size of 44x44 µm in diameter was used with a repetition rate of 6 Hz (non-encrusted forms) and 8 Hz (encrusted forms). For the smallest foraminifera, the spot size was decreased to 30x30 µm to ensure ablation within a single chamber. Depth profiles were obtained on each chamber (F through up to F7). If chambers were large enough, up to 3 repeat spot analyses were obtained to assess reproducibility. Masses measured were 24Mg, 25Mg, 27Al, 44Ca, 55Mn, 88Sr, 89Y, and 138Ba. SRM NIST 610, 612, and 614 glass standards were run before and after each batch of samples as an external standard. An Orbulina universa shell, which is demonstrated to have highly reproducible trace element profiles throughout, was analyzed before and after each run as an internal working standard (7.0 ± 0.7 mmol/mol Mg/Ca, 2σ, Fehrenbacher et al., 2015). Outliers in the Mg/Ca 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 et al., 2011). Stable isotopes, δ18O and δ13C of calcite (δ18Oc and δ13Cc), were analyzed on individual foraminifera, ranging in weight from 5 to 95 µg, after LA-ICP-MS analyses were completed. Foraminifera were roasted under vacuum at 75 ºC for 1 hour to eliminate remaining volatile organics from carbon tape. Isotopic analyses were performed at The University of California, Davis Stable Isotope Laboratory, on a Fisons Optima isotope ratio mass spectrometer (IRMS). The IRMS is calibrated using the NBS-19 standard and has a long-term one sigma precision for carbonates ± 0.04 ‰ and ± 0.05 ‰ for δ13Cc and δ18Oc, respectively. This is based on 110 standards analyzed during the summer 2016.
  3. What similar or related data should the user be aware of?
    Vetter, L., Spero, H. J., Russell, A. D., and Fehrenbacher, J. S., 2013, LA-ICP-MS depth profiling perspective on cleaning protocols for elemental analyses in planktic foraminifers: Geochemistry Geophysics Geosystems Volume 14, No. 8.

    Online Links:

    Fehrenbacher, J. S., Spero, H. J., Russell, A. D., Vetter, L., and Eggins, S., 2015, Optimizing LA-ICP-MS analytical procedures for elemental depth profiling of foraminifera shells: Chemical Geology Volume 407.

    Online Links:

    Paton, C., Hellstrom, J., Paul, B., Woodhead, J., and Hergt, J., 2011, Iolite: Freeware for the visualization and processing of mass spectrometric data: Journal of Analytical Atomic Spectometry Volume 26, No. 12.

    Online Links:


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

  1. How well have the observations been checked?
    No formal attribute accuracy tests were conducted.
  2. How accurate are the geographic locations?
    A formal accuracy assessment of the horizontal positional information in the dataset has not been conducted.
  3. How accurate are the heights or depths?
    A formal accuracy assessment of the vertical positional information in the dataset has either not been conducted or is not applicable.
  4. Where are the gaps in the data? What is missing?
    Dataset 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?
    No formal logical accuracy tests were conducted.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. Please see 'Distribution Info' for details.
Use_Constraints:
Public domain data from the U.S. Government are freely redistributable with proper metadata and source attribution. The U.S. Geological Survey requests that it be acknowledged as the originator of this dataset in any future products or research derived from these data.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey St. Petersburg Coastal and Marine Science Center
    Attn: Caitlin Reynolds
    Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8046 (voice)
    creynods@usgs.gov
  2. What's the catalog number I need to order this data set? isotopes.csv; Mg_Ca_Compiled_all.csv; Raw_Counts_and_Flux Data.csv; Mg_Ca_Compiled_averages.csv
  3. What legal disclaimers am I supposed to read?
    Distributor assumes no liability for misuse of data. This publication was prepared by an agency of the United States Government. 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. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 13-Apr-2018
Metadata author:
U.S. Geological Survey
Attn: Caitlin Reynolds
Geologist
600 4th Street South
St. Petersburg, FL
USA

727-502-8046 (voice)
creynolds@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/Gtrunc_metadata.faq.html>
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