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    • Data for Novel field trial for ocean alkalinity enhancement using electrochemically derived aqueous alkalinity from 2024-11-07 to 2025-02-08 (NCEI Accession 0307424)

    Metadata Updated: November 1, 2025

    Ocean alkalinity enhancement is a proposed method of marine carbon dioxide removal that enhances the ocean’s uptake of atmospheric carbon dioxide (CO2) and converts it to dissolved bicarbonate for long-term ocean storage. This method of marine carbon dioxide removal has been gaining attention for its potential to durably (10,000+ years) store large amounts of CO2 (Gt+ where 1 Gt = 1 x 10^9 tons), while potentially ameliorating acidification in the vicinity of the alkalinity release. This study focuses on a novel release of electrochemically derived aqueous alkalinity into Sequim Bay, WA, through a previously established wastewater treatment plant (WWTP). This research was made possible through the collaboration of industry, academic, and federal partners, which enabled the establishment of an Ebb Carbon electrochemical mCDR system at the Pacific Northwest National Laboratory in Sequim, WA, for ocean alkalinity enhancement field trials. During these field trials, pH was measured across the WWTP system from the initial alkalinity dosing, throughout the WWTP, and at the outfall. We use the NBS scale for pH throughout this study as it is the scale used in discharge permit limits specified for WWTP and NPDES regulation and compliance monitoring. The background pHNBS of Sequim Bay seawater was between 7.5 to 7.7 for the November and February field tests. The mixing tank's pHNBS was raised to the maximum value permitted for the WWTP (9.0) and maintained across the system (±0.2) during the outfall releases. At the outfall, the elevated pH and alkalinity was quickly diluted, such that the region with a measurable signal was limited to within ~2.5 m of the discharge pipe. We were able to successfully monitor an increase in pHNBS across all four pulses of alkalinity-enhanced seawater discharge during the February 2025 field trial, with peak pHNBS values of 8.3 or 8.1, as recorded by outfall-adjacent YSI Exo 2 sonde and SAMI-pH sensors, respectively. The alkalinity-enhanced seawater did not measurably alter the surrounding waters' temperature, salinity, turbidity, or oxygen. This study provides proof-of-concept for a conservative small-scale release of electrochemically generated alkalinity-enhanced seawater from a coastal outfall.

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    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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    Dates

    Metadata Date 2025-10-01T13:09:30Z
    Metadata Created Date October 2, 2025
    Metadata Updated Date November 1, 2025
    Reference Date(s) September 2, 2025 (publication)
    Frequency Of Update asNeeded

    Metadata Source

    Harvested from NOAA/NESDIS/ncei/accessions

    Other Data Resources

    Graphic Preview

    Graphic not available.

    Additional Metadata

    Resource Type Nongeographicdataset
    Metadata Date 2025-10-01T13:09:30Z
    Metadata Created Date October 2, 2025
    Metadata Updated Date November 1, 2025
    Reference Date(s) September 2, 2025 (publication)
    Responsible Party (Point of Contact)
    Contact Email
    Guid gov.noaa.nodc:0307424
    Access Constraints Cite as: Savoie, Allison M.; Ringham, Mallory; Torres Sanchez, Carolina; Carter, Brendan R.; Dougherty, Sean; Feely, Richard A.; Hegeman, Dave; Herndon, Julian; Khangaonkar, Tarang; Loretz, Jeremy; Minck, Tyson; Pelman, Todd; Premathilake, Lakshitha; Subban, Chinmayee; Vance, Jesse; Ward, Nicholas D. (2025). Data for Novel field trial for ocean alkalinity enhancement using electrochemically derived aqueous alkalinity from 2024-11-07 to 2025-02-08 (NCEI Accession 0307424). [indicate subset used]. NOAA National Centers for Environmental Information. Dataset. https://doi.org/10.25921/7zf4-3135. Accessed [date]., Use liability: NOAA and NCEI cannot provide any warranty as to the accuracy, reliability, or completeness of furnished data. Users assume responsibility to determine the usability of these data. The user is responsible for the results of any application of this data for other than its intended purpose.
    Bbox East Long -123.045
    Bbox North Lat 48.078611
    Bbox South Lat 48.078611
    Bbox West Long -123.045
    Coupled Resource
    Frequency Of Update asNeeded
    Graphic Preview Description Graphic not available.
    Graphic Preview File https://www.ncei.noaa.gov/access/metadata/landing-page/bin/gfx?id=gov.noaa.nodc:0307424
    Graphic Preview Type PNG
    Harvest Object Id c44a7212-c122-467d-86cf-23f1bd891c78
    Harvest Source Id c084a438-6f6b-470d-93e0-16aeddb9f513
    Harvest Source Title NOAA/NESDIS/ncei/accessions
    Licence accessLevel: Public
    Lineage
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Point", "coordinates": [-123.045, 48.078611]}
    Progress completed
    Spatial Data Service Type
    Spatial Reference System
    Spatial Harvester True
    Temporal Extent Begin 2024-11-07
    Temporal Extent End 2025-02-08

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