Water oxygen and hydrogen isotope ratios from the West Florida Shelf

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Frequently anticipated questions:

What does this data set describe?

Title:
Water oxygen and hydrogen isotope ratios from the West Florida Shelf
Abstract:
To assess the spatial and temporal hydrographic variability along the West Florida Shelf (including Tampa Bay and Charlotte Harbor), stable oxygen (d18O) and hydrogen (dD) isotope ratios were measured using water samples collected from across the region by the U.S. Geological Survey (USGS) and collaborators. Surface, bottom, and groundwater samples from a marine well network along the central West Florida Shelf, as well as surface, intermediate, and bottom water samples within the Tampa Bay estuary were collected from 2022 2024 during USGS Field Activity Numbers (FANs) 2022-340-FA (Chestang and others, 2025) and 2022-349-DD (Hunt, 2025; Tamborski and others, 2025). Additional samples from Tampa Bay marine and riverine surface waters were collected in 2025, corresponding to USGS FAN 2025-311-DD. This data release also includes d18O and dD data obtained by digitizing legacy data previously published by Sackett and others (1991) and Netratanawong (1995).
Supplemental_Information:
Sampling activities correspond to the USGS FANs 2022-340-FA, 2022-349-DD, and 2025-311-DD. Alternative FANs (altFANs) were designated during individual collection events for 2022-340-FA: 22WFS05, 23WFS01, 23WFS02, 23WFS03, 23WFS04, and 24WFS01. Additional survey and data details are available from the USGS Coastal and Marine Geoscience Data System (CMGDS) at https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-340-FA, https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-349-DD, and https://cmgds.marine.usgs.gov/fan_info.php?fan=2025-311-DD, respectively.
  1. How might this data set be cited?
    Mette, Madelyn J., 20260610, Water oxygen and hydrogen isotope ratios from the West Florida Shelf:.

    This is part of the following larger work.

    Mette, Madelyn J., Smith, Christopher G., Jacobs, Jessica A., Richey, Julie N., Tamborski, Joseph J., Alorda-Kleinglass, Aaron, Rogers, Jaime A., Jackson, Kendal, Conway, Tim M., Hunt, Hannah, Chappell, P. Dreux, Buck, Kristen N., Boiteau, Rene M., and Knapp, Angela N., 20260610, Water Oxygen and Hydrogen Isotope Ratios From the West Florida Shelf: U.S. Geological Survey data release doi:10.5066/P13MDRY8, 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: -85.0285
    East_Bounding_Coordinate: -81.8473
    North_Bounding_Coordinate: 28.4991
    South_Bounding_Coordinate: 26.1297
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 19-Mar-1990
    Ending_Date: 29-May-2025
    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?
      This is a Point data set. It contains the following vector data types (SDTS terminology):
      • Point (414)
    2. What coordinate system is used to represent geographic features?
      The horizontal datum used is WGS 1984.
      The ellipsoid used is WGS_84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    Entity_and_Attribute_Overview:
    WFS_d18O_dD_sal.zip: Comma-separated values file (.csv) of the processed data for stable oxygen (d18O) and hydrogen isotopes (dD) of surface and ground water samples collected from Tampa Bay, Charlotte Harbor, and the West Florida Shelf regions. Detailed attribute descriptions for these files are included in the data dictionary (WFS_d18O_dD_sal_Data_Dictionary.docx). These metadata are not complete without this file. All files are available for download in WFS_d18O_dD_sal.zip.
    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)
    • Madelyn J. Mette
  2. Who also contributed to the data set?
    Funding and resources for this project are credited to the National Science Foundation (National Science Foundation Grant Award OCE-2148989, Project 880516), USGS Coastal Marine Hazards and Resources Program (CMHRP), and Land Change Science Program (LCS). Legacy data included in this release were compiled from previously published resources by Sackett and others (1991) and Netratanawong (1995).
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Madelyn J. Mette
    600 4th Street South
    St. Petersburg, FL

    727-502-8130 (voice)
    mmette@usgs.gov

Why was the data set created?

This data was collected to characterize variability in the relationship between salinity and water oxygen isotope ratios in surface and groundwater along the West Florida Shelf.

How was the data set created?

  1. From what previous works were the data drawn?
    Chestang and others (2025) (source 1 of 5)
    Chestang, Emma S., Ellis, Alisha M., Smith, Christopher G., Knapp, Angela, Tamborski, Joseph J., and Lindgren, Andrew, 20250212, Short-lived radium-isotope (radium-223 and -224) specific activity for samples collected between November 2022 and March 2024 along the West Florida Shelf (Indian Rocks Beach, Nature Coast, and Venice Headland): U.S. Geological Survey, St. Petersburg, Florida.

    Online Links:

    Type_of_Source_Media: Digital and/or Hardcopy
    Source_Contribution:
    Salinity and location coordinates for samples associated with USGS FAN 2022-340-FA were compiled into this data release.
    Sackett and others (1991) (source 2 of 5)
    Sackett, William M., Netratanawong, Toedsit, and Holmes, M. Elizabeth, 1991, Stable carbon and oxygen isotope variations in waters of the Tampa Bay estuary: Proceedings of the Tampa Bay Area Scientific Information Symposium 2.

    Online Links:

    Type_of_Source_Media: Digital and/or Hardcopy
    Source_Contribution:
    Sample salinity, d18O, and location coordinate data were digitized from this publication and compiled into this data release and labeled as Field Activity 'Sackett'. Numbered sample locations were digitized from Figure 3. Numbered sample d18O and salinity values were digitized from Figure 5.
    Netratanawong (1995) (source 3 of 5)
    Netratanawong, Toedsit, 199505, Stable isotopic investigation of the hydrological cycle of west-central Florida: University of South Florida, Tampa, FL.

    Online Links:

    Type_of_Source_Media: Digital and/or Hardcopy
    Source_Contribution:
    Sample salinity, d18O, and location coordinate data were digitized from this publication and compiled into this data release and labeled as Field Activity 'Netratanawong'. Location coordinates from Figure 3 were interpreted to match d18O and salinity data from Figure 13a based on salinity values, whereby sites further upriver from Tampa Bay were assumed to be of lowest salinity, and sites closest to Tampa Bay of highest salinity, consistent with typical estuarine salinity gradients (de Miranda and others, 2017).
    Hunt (2025) (source 4 of 5)
    Hunt, Hannah R., 20250609, Isotopic fingerprints of the coastal margins: tracing dissolved iron sources from land to sea: University of South Florida, Tampa, FL.

    Online Links:

    Type_of_Source_Media: Digital and/or Hardcopy
    Source_Contribution:
    Salinity and location coordinates for samples associated with USGS FAN 2022-349-DD Estuary were compiled into this data release.
    Tamborski and others (2025) (source 5 of 5)
    Tamborski, Joseph, Lindgren, Andrew, Alorda-Kleinglass, Aaron, Buck, Kristen N., Boiteau, Rene M., Chappell, Phoebe Dreux, Conway, Timothy M., Smith, Chris, and Knapp, Angela N., 20250919, Dissolved radium from STING I Cruise AE2305 on R/V Atlantic Explorer and STING II Cruise EN704 on R/V Endeavor and U.S. Geological Survey small boat surveys in the Gulf of Mexico from Feb to Jul 2023: Biological and Chemical Oceanography Data Management Office (BCO-DMO), Woods Hole, MA.

    Online Links:

    Type_of_Source_Media: Digital and/or Hardcopy
    Source_Contribution:
    Salinity and location coordinates for samples associated with USGS FAN 2022-349-DD Offshore were compiled into this data release.
  2. How were the data generated, processed, and modified?
    Date: 08-Mar-2024 (process 1 of 3)
    Sample Collection: For the data compiled from previously published legacy data, users are advised to refer to the source publications for more information about the sample collection methodology used: Sackett and others (1991), Field Activity 'Sackett'; Netratanawong (1995), Field Activity 'Netratanawong'. Please refer to the 'Data Digitization' process step below for the methods used to digitize the location and salinity information from these source publications. For USGS FANs 2025-311-DD, 2022-349-DD, and 2022-340-FA: Latitude and longitude coordinates were read directly off a Garmin® GPS plotter and recorded by hand in a field notebook. 2022-349-DD Offshore: Samples were passed through a 1 micrometer (µm) prefilter to remove suspended particles, loaded into 2 milliliter (mL) glass autosampler vials, and refrigerated until ready for analysis. The salinity values were compiled from its previous publication for inclusion in this data release, refer to Tamborski and others (2025) for more information. 2022-349-DD Estuary: Samples were passed through a 1 µm prefilter to remove suspended particles, loaded into 2 mL glass autosampler vials, and refrigerated until ready for analysis. The salinity values were compiled from its previous publication for inclusion in this data release, refer to Hunt (2025) for more information. 2022-340-FA: A known volume of groundwater or water column water was collected from each well/station using a diaphragm pump. Water column samples for subFANs 22WFS05 and 23WFS01 were collected and extracted using a flow through cell system in the field. Surface samples for the remainder of the sampling events were collected in one or more field-rinsed 20-liter (L) cube containers and extracted after returning to shore. All groundwater samples were collected in field-rinsed 2-L high density polyethylene bottles and extracted back onshore. Samples were passed through a 1 µm prefilter to remove suspended particles, loaded into 2 mL glass autosampler vials, and refrigerated until ready for analysis. The salinity values were compiled from its previous publication for inclusion in this data release, refer to Chestang and others (2025) for more information. 2025-311-DD: Seawater samples were collected on a boat from Double Branch Creek in Upper Tampa Bay in April 2025, and along the Little Manatee River in May 2025, by University of South Florida (USF) researchers Jaime Rogers and Kendal Jackson. Seawater was sampled by submerging a 50 mL centrifuge vial approximately 0.5 m below the water surface, first filled and emptied to rinse, then filled and capped underwater to minimize headspace. Samples were kept refrigerated prior to filtering through a 1 µm filter into a 2 mL glass autosampler vial in preparation for analysis. Salinity was recorded at the time of sample collection using a handheld YSI ProDDS digital water quality meter. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Christopher G. Smith
    Research Geologist
    600 4th Street South
    St. Petersburg, FL
    USA

    (727) 502-8035 (voice)
    cgsmith@usgs.gov
    Date: 28-Jun-2025 (process 2 of 3)
    Data Analysis: For the data compiled from previously published legacy data, users are advised to refer to the source publications for more information about the data analysis methodology used: Sackett and others (1991), Field Activity 'Sackett'; Netratanawong (1995), Field Activity 'Netratanawong'. In these two publications, salinity was reported in parts per thousand (ppt); conversion to practical salinity units (PSU) was not applied, as any difference between units falls below the reported measurement precision. Oxygen isotope ratio (d18O) was reported relative to Standard Mean Ocean Water (SMOW); conversion to relative to Vienna Standard Mean Ocean Water (VSMOW) was not applied, as VSMOW has an oxygen isotopic composition practically identical to the defined SMOW (Gonfiantini, 1984). Hydrogen isotopic ratio (dD) was not reported in the original publication and is therefore not included in the data release for these samples. Field Activities 2025-311-DD, 2022-349-DD, and 2022-340-FA: Water samples were analyzed for stable hydrogen (dD) and oxygen (d18O) isotope ratios on a Picarro L2130-i Isotope Analyzer at the USGS St. Petersburg Coastal and Marine Science Center (SPCMSC), St. Petersburg, Florida. For each isotopic measurement, the water sample was injected and measured six times. To account for memory effects, only the last three injections were used to calculate mean isotopic values (Picarro, Inc., 2026). The isotopic composition of an in-house reference water (IRW) was calibrated to VSMOW scale using a linear regression-based isotopic calibration from three reference standards (USGS50, δ2H = +32.8‰, d18O = +4.95‰; W115143A, d2H = -4.8‰, d18O = -1.19‰; and W115135A, δ2H = -53.2‰, d18O = -8.52‰). The IRW was analyzed three times at the beginning, middle and end of each sample run, and raw sample isotope ratios were corrected to VSMOW scale using the linear calibration. Each run was assessed for drift by determining whether there was a significant linear trend in the isotopic values across the nine IRW analyses, then a linear correction was applied to the data if necessary. All isotopic values for these samples are reported in parts per mil (‰) relative to VSMOW. The long-term precision of the instrument was 0.08 and 0.42 for d18O and dD, respectively, based on 140 measurements of IRW from 18 sample runs from 2025-03-07 to 2025-06-28. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Jessica Jacobs
    Physical Scientist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8041 (voice)
    jajacobs@usgs.gov
    Date: 25-Sep-2025 (process 3 of 3)
    Data Digitization: Data from the legacy publications Sackett and others (1991) and Netratanawong (1995) were digitized from its original source using the Automeris© LLC web tool, https://automeris.io/wpd/. Screenshots of the data figures were uploaded to the web tool, calibrated as 2D XY Axes type figures by manually selecting axis limits and assigning labeled values, and datapoints manually marked. Data were exported using the copy to clipboard function. In Netratanawong (1995), location coordinates from Figure 3 were interpreted to match data from Figure 13a based on salinity values, whereby sites further upriver from Tampa Bay were assumed to be of lowest salinity, and sites closest to Tampa Bay of highest salinity (de Miranda and others, 2017). In Sackett (1991), location coordinates from Figure 3 were matched to data from Figure 5 based on sample labels shown in each figure. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Madelyn J. Mette
    Research Physical Scientist
    600 4th Street South
    St. Petersburg, FL
    USA

    727-502-8130 (voice)
    mmette@usgs.gov
  3. What similar or related data should the user be aware of?
    Inc., Picarro, 2026, L2140-i and L2130-i isotopic water analyzer and peripherals installation and operation manual: Picarro Inc., Santa Clara, CA.

    Online Links:

    Gonfiantini, Roberto, 198404, I.A.E.A. advisory group meeting on stable isotope reference samples for geochemical and hydrological investigations, Vienna, Austria, September 19-21, 1983: Chemical Geology Volume 46, Issue 1, Elsevier B.V., Amsterdam, Netherlands.

    Online Links:

    Luiz Bruner de Miranda, Andutta, Fernando Pinheiro, Kjerfve, Bj rn, and Belmiro Mendes de Castro Filho, 2017, Fundamentals of Estuarine Physical Oceanography: Ocean Engineering & Oceanography Volume 8, Springer, Singapore.

    Online Links:

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

  1. How well have the observations been checked?
    Refer to the accompanying data dictionary document (WFS_d18O_dD_sal_Data_Dictionary.docx) and process steps for more information regarding instrument information, calibrations, and precision. These data were processed and reviewed in accordance with USGS Quality Management System requirements.
  2. How accurate are the geographic locations?
    For the data compiled from previously published legacy data, users are advised to refer to the source publications for more information about the horizontal positional accuracy: Sackett and others (1991) and Netratanawong (1995). Please also refer to the 'Data Digitization' process step below for the methods used to digitize the location information associated with a sample. For USGS FANs 2025-311-DD, 2022-349-DD, and 2022-340-FA: Latitude and longitude coordinates were read directly off a Garmin® global positioning systems (GPS) plotter and recorded by hand in a field notebook. Information was digitized, reviewed, and subject to error associated with the GPS device, which is ± 15 meters (m). Coordinates were referenced to the World Geodetic System of 1984 (WGS 84). The horizontal datum was not provided in Sackett and others (1991) and Netratanawong (1995).
  3. How accurate are the heights or depths?
    For the data compiled from previously published legacy data, users are advised to refer to the source publications for more information about the vertical positional accuracy: Sackett and others (1991) and Netratanawong (1995). Please also refer to the 'Data Digitization' process step below for the methods used to digitize the location information associated with a sample. For USGS FANs 2025-311-DD, 2022-349-DD, and 2022-340-FA: Sampling depth was based on total water depth at each site and includes 0.5 m below the surface of the ocean and 0.5 m above the sea floor. Vertical accuracy is thus assessed to be approximately ± 0.5 m. Vertical accuracy of the wells was measured relative to the seafloor, with an uncertainty of approximately ± 0.1 m. These data are not referenced to a vertical coordinate system.
  4. Where are the gaps in the data? What is missing?
    For the data compiled from previously published legacy data, users are advised to refer to the source publications for more information about data completeness: Sackett and others (1991) and Netratanawong (1995). All samples from 2022-340-FA were originally collected for the purpose of measuring Radium-223 and Radium-224, and only some of the samples from this field activity were subsampled for d18O and dD. Therefore, not all samples included in the radium data release (Chestang and others, 2025) are included in this data release. Additionally, one sample from Hunt (2025) was excluded in this data release due to uncertainty with its cross-reference to available field data (Sample ID: EA24/PR2). Otherwise, all data from previously published resources were included in this data release.
  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 No access constraints. Please see 'Distribution Information' for details.
Use_Constraints These data are marked with a Creative Commons CC0 1.0 Universal License. These data are in the public domain and do not have any use constraints. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
    Attn: USGS SPCMSC Data Management
    600 4th Street South
    Saint Petersburg, FL
    United States

    727-502-8000 (voice)
    gs-g-spcmsc_data_inquiries@usgs.gov
  2. What's the catalog number I need to order this data set? WFS_d18O_dD_sal.csv, WFS_d18O_dD_sal_Data_Dictionary.docx
  3. What legal disclaimers am I supposed to read?
    Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data for other purposes, nor on all computer systems, nor shall the act of distribution constitute any such warranty. Any use of trade, firm, or product names 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?

Dates:
Last modified: 10-Jun-2026
Metadata author:
U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center
Attn: USGS SPCMSC Data Management
600 4th Street South
Saint Petersburg, FL
United States

727-502-8000 (voice)
gs-g-spcmsc_data_inquiries@usgs.gov
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/spcmsc/WFS_d18O_dD_sal_metadata.faq.html>
Generated by mp version 2.9.51 on Wed Jun 10 11:00:07 2026