Madelyn J. Mette 20260610 tabular digital data Madelyn J. Mette Christopher G. Smith Jessica A. Jacobs Julie N. Richey Joseph J. Tamborski Aaron Alorda-Kleinglass Jaime A. Rogers Kendal Jackson Tim M. Conway Hannah Hunt P. Dreux Chappell Kristen N. Buck Rene M. Boiteau Angela N. Knapp 20260610 U.S. Geological Survey data release doi:10.5066/P13MDRY8 St. Petersburg, Florida U.S. Geological Survey - St. Petersburg Coastal and Marine Science Center https://doi.org/10.5066/P13MDRY8 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). 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. 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. 19900319 20250529 ground condition Complete None planned -85.0285 -81.8473 28.4991 26.1297 USGS Metadata Identifier USGS:1df4b5e5-bce6-414e-9fd7-584406ee5070 ISO 19115 Topic Category geoscientificInformation location environment USGS Thesaurus tracer study hydrology geochemistry isotopic analysis light stable isotope analysis salinity water temperature water sampling ocean characteristics ocean processes None ocean U.S. Geological Survey USGS St. Petersburg Coastal and Marine Science Center SPCMSC d18O dD Geographic Names Information System (GNIS) State of Florida Gulf of America Tampa Bay Charlotte Harbor None West Florida Shelf Gulf of Mexico None 1990 1991 1993 2021 2022 2023 2024 2025 No access constraints. Please see 'Distribution Information' for details. 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. U.S. Geological Survey Madelyn J. Mette Mailing

600 4th Street South

St. Petersburg FL 33701 727-502-8130 mmette@usgs.gov 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). Environment as of Metadata Creation: macOS Sequoia 15.7.3; Microsoft Excel for Mac Version 16.105.2 (26012530); Picarro Cavity Ring-Down Spectroscopy (CRDS) Data Viewer Version g2000-1.6.0.53 Picarro Inc. 2026 Document number 40035 Revision G Santa Clara, CA Picarro Inc. https://www.picarro.com/ https://www.picarro.com/environmental/l2140i_and_l2130i_isotopic_water_analyzer_and_peripherals_installation_and_operation Roberto Gonfiantini 198404 Chemical Geology Volume 46, Issue 1 Amsterdam, Netherlands Elsevier B.V. https://doi.org/10.1016/0009-2541(84)90167-0 Luiz Bruner de Miranda Fernando Pinheiro Andutta Bj rn Kjerfve Belmiro Mendes de Castro Filho 2017 Ocean Engineering & Oceanography Volume 8 Singapore Springer https://link.springer.com/book/10.1007/978-981-10-3041-3 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. No formal logical accuracy tests were conducted. 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. 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). 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. Emma S. Chestang Alisha M. Ellis Christopher G. Smith Angela Knapp Joseph J. Tamborski Andrew Lindgren 20250212 2.0 tabular digital data St. Petersburg, Florida U.S. Geological Survey https://doi.org/10.5066/P1ZIOFSX Digital and/or Hardcopy 20221114 20240308 ground condition Chestang and others (2025) Salinity and location coordinates for samples associated with USGS FAN 2022-340-FA were compiled into this data release. William M. Sackett Toedsit Netratanawong M. Elizabeth Holmes 1991 publication Proceedings of the Tampa Bay Area Scientific Information Symposium 2 https://tbep.org/get-involved/calendar/basis/ Digital and/or Hardcopy 19900319 1991020 ground condition Sackett and others (1991) 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. Toedsit Netratanawong 199505 publication Tampa, FL University of South Florida https://digitalcommons.usf.edu/etd/9837 Digital and/or Hardcopy 19930115 ground condition Netratanawong (1995) 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). Hannah R. Hunt 20250609 publication Tampa, FL University of South Florida https://digitalcommons.usf.edu/etd/10872 Digital and/or Hardcopy 20221122 20230817 ground condition Hunt (2025) Salinity and location coordinates for samples associated with USGS FAN 2022-349-DD Estuary were compiled into this data release. Joseph Tamborski Andrew Lindgren Aaron Alorda-Kleinglass Kristen N. Buck Rene M. Boiteau Phoebe Dreux Chappell Timothy M. Conway Chris Smith Angela N. Knapp 20250919 publication Woods Hole, MA Biological and Chemical Oceanography Data Management Office (BCO-DMO) https://doi.org/10.26008/1912/bco-dmo.982223.1 Digital and/or Hardcopy 20230220 20230712 ground condition Tamborski and others (2025) Salinity and location coordinates for samples associated with USGS FAN 2022-349-DD Offshore were compiled into this data release. 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. 20240308 U.S. Geological Survey Christopher G. Smith Research Geologist Mailing and physical

600 4th Street South

St. Petersburg FL 33701 USA (727) 502-8035 cgsmith@usgs.gov 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. 20250628 U.S. Geological Survey Jessica Jacobs Physical Scientist Mailing and physical

600 4th Street South

St. Petersburg FL 33701 USA 727-502-8041 jajacobs@usgs.gov 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. 20250925 U.S. Geological Survey Madelyn J. Mette Research Physical Scientist Mailing and physical

600 4th Street South

St. Petersburg FL 33701 USA 727-502-8130 mmette@usgs.gov Point Point 414 WGS 1984 WGS_84 6378137.0 298.257223563 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. 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. U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center USGS SPCMSC Data Management mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8000 gs-g-spcmsc_data_inquiries@usgs.gov WFS_d18O_dD_sal.csv, WFS_d18O_dD_sal_Data_Dictionary.docx 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. comma-delimited text, Microsoft Word format Unzip https://coastal.er.usgs.gov/data-release/doi-P13MDRY8/data/WFS_d18O_dD_sal.zip None 20260610 U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center USGS SPCMSC Data Management mailing and physical

600 4th Street South

Saint Petersburg FL 33701 United States 727-502-8000 gs-g-spcmsc_data_inquiries@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998