http://lod.bco-dmo.org/id/dataset/1000973
eng; USA
utf8
dataset
Highest level of data collection, from a common set of sensors or instrumentation, usually within the same research project
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
2026-06-11
ISO 19115-2 Geographic Information - Metadata - Part 2: Extensions for Imagery and Gridded Data
ISO 19115-2:2009(E)
Boric acid dissociation constants (pKB) from spectrophotometrically calibrated electrode measurements made in natural seawater across estuarine to open-ocean conditions
2026-06-24
publication
2026-06-24
revision
Woods Hole Oceanographic Institution (WHOI BCO-DMO)
2026-06-25
publication
https://doi.org/10.26008/1912/bco-dmo.1000973.1
Robert Byrne
University of South Florida
principalInvestigator
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
publisher
Cite this dataset as: Martin Mayor, M., Byrne, R. (2026) Boric acid dissociation constants (pKB) from spectrophotometrically calibrated electrode measurements made in natural seawater across estuarine to open-ocean conditions. Biological and Chemical Oceanography Data Management Office (BCO-DMO). (Version 1) Version Date 2026-06-24 [if applicable, indicate subset used]. doi:10.26008/1912/bco-dmo.1000973.1 [access date]
Boric acid dissociation constants in freshwater and marine conditions Dataset Description: Methods and Sampling: <p>Potentiometric measurements were made using a glass electrode that was spectrophotometrically calibrated following the methods described in Easley and Byrne (2012) and Martell-Bonet and Byrne (2020). The spectrophotometric measurements were made following the guidelines of Clayton and Byrne (1993) and Dickson et al. (2007).</p>
<p>Following the methodology introduced by Byrne and Kester (1974), sodium borate decahydrate (borax) was added to natural seawater at different <em>S</em><sub>P</sub>-<em>T</em> pairs to determine the pH<sub>T</sub> at which the salt addition caused no change in pH<sub>T</sub>. The pH<sub>T</sub> at which the addition of borax causes no change is the p<em>K</em><sub>B</sub> for that specific <em>S</em><sub>P</sub>-<em>T</em> pair. For each <em>S</em><sub>P</sub>-<em>T</em> pair, approximately 15 samples were analyzed. From these, two samples were selected: (1) the sample with the lowest pH<sub>initial</sub> that lowered upon the addition of borax, and (2) the sample with the highest pH<sub>initial</sub> that increased upon the addition of borax. The experimental p<em>K</em><sub>B</sub> (exp-p<em>K</em><sub>B</sub>) for each<em> S</em><sub>P</sub>–<em>T</em> pair was calculated as the mean of the initial and final pH values of the two selected samples; specifically, as the average of pH<sub>initial</sub> for samples (1) and (2) and the average of pH<sub>final</sub> for samples (1) and (2).</p>
Funding provided by NSF Division of Ocean Sciences (NSF OCE) Award Number: OCE-2042935 Award URL: https://www.nsf.gov/awardsearch/show-award?AWD_ID=2042935
completed
Robert Byrne
University of South Florida
727-553-1508
140 Seventh Ave. South
St. Petersburg
Florida
33701
USA
rhbyrne@usf.edu
pointOfContact
asNeeded
Dataset Version: 1
Unknown
source
Target_t_C
Target_T_K
Target_Sal
Temp_C
Temp_K
Sal
exp_pKB_combined
borax_added_mg
sw_origin
sw_collection_year
Agilent 8453
Ertco-Eutechnics Model 4400
Guildline Portasal 8410A Laboratory Salinometer
Thermo Scientific Orion ROSS Ultra glass combination pH electrode
theme
None, User defined
reference_paper
temperature of sample or a generic measurement (not in-situ water temp)
salinity
water temperature at measurement depth
equilibrium constant
treatment
sample description
year
featureType
BCO-DMO Standard Parameters
Agilent 8453 UV-visible spectrophotometer
digital thermometer
Guildline Portasal 8410 series salinometer
Thermo Fisher Scientific ORION Ross pH electrode series
instrument
BCO-DMO Standard Instruments
otherRestrictions
otherRestrictions
Access Constraints: none. Use Constraints: Please follow guidelines at: http://www.bco-dmo.org/terms-use Distribution liability: Under no circumstances shall BCO-DMO be liable for any direct, incidental, special, consequential, indirect, or punitive damages that result from the use of, or the inability to use, the materials in this data submission. If you are dissatisfied with any materials in this data submission your sole and exclusive remedy is to discontinue use.
Spectrophotometric Determinations of Carbonic Acid Dissociation Constants for Estuarine Conditions
https://osprey.bco-dmo.org/project/961585
Spectrophotometric Determinations of Carbonic Acid Dissociation Constants for Estuarine Conditions
<p><em><strong>NSF Award Abstract</strong></em><br />
Human health and well-being are linked in many ways to the health of our estuaries and coastal ocean waters. Yet surprisingly, we know less about some aspects of these important waters than we do the more distant waters of the deep ocean. This project will use state-of-the-art spectrophotometric methods (that is, light- and color-based methods) to advance our understanding of the fundamental and ever-changing chemistry of these waters and, eventually, the effects of these changes on marine life. The focus of this study will be to understand the chemistry of carbon dioxide in seawater. The new tools we will use are recently characterized pH indicators — chemicals that change color in seawater depending on the acidity of that water. These specially selected, purified indicators can be used to measure pH with unsurpassed precision and accuracy. We will use the indicators in laboratory experiments to determine how a critical parameter of the carbon dioxide system (a dissociation constant known as “K2”) changes depending on the temperature and salinity of the water. Characterizing K2 has been a goal of marine chemists for more than 50 years. The better we know K2, the better we can understand and predict how carbon moves through and cycles within natural waters. These measurements will expand our understanding of not only K2 but also the many other seawater characteristics that can be calculated from K2. Ultimately, this work will facilitate the interpretation and prediction of many ocean processes relevant to human health and coastal economies, such as ocean acidification (the lowering of ocean pH due to increasing carbon dioxide in the atmosphere) and calcium carbonate dissolution (the resulting dissolution of seashell material). The results will thus lay the groundwork for new perspectives on how ocean acidification affects the various shelled organisms that serve as food for economically important marine animals/fisheries and for people. The results of this work will also help to improve models of carbon dioxide dynamics in lakes, rivers, underground pore waters, and physiological fluids. As regards broader impacts, this work will help the PI continue to transfer his knowledge on this important topic to the next generation via his training of graduate, undergraduate, and high school students. This project would support one graduate and one undergraduate student, as well as help the current research projects of two minority doctoral students. Lastly, the PI plans to continue his involvement in the Bridge to the Doctoral Program aimed at getting minority students involved in the sciences.</p>
<p>In seawater, two carbonic acid dissociation constants (K1 and K2) describe the relationship between solution pH and the relative concentrations of dissolved carbonate ions, bicarbonate ions, and dissolved carbon dioxide. Accurate characterization of these CO2-system constants over broad ranges of environmental conditions has been a much sought-after goal for more than 50 years because knowledge of these terms is essential for quantitatively interpreting and predicting the biogeochemical cycling of carbon in all natural aqueous systems. The accuracy of CO2-system calculations is especially sensitive to uncertainties in K2, the equilibrium constant that describes the dissociation of bicarbonate ions to produce hydrogen ions and carbonate ions. This research project is designed to use spectrophotometric pH measurements (solely) to characterize this important constant. The purified pH indicators to be used in this work provide seawater pH measurements of unsurpassed precision and accuracy. Using select indicators whose properties have recently been characterized over freshwater-to-seawater ranges of salinity and temperature, we will determine K2 over similar ranges so as to improve the accuracy of CO2-system calculations in estuaries and coastal ocean waters. The resulting insight into equilibrium characteristics will facilitate interpretations and predictions of pH buffering in aqueous systems, provide an improved understanding of calcium carbonate solubility behavior, and lead to improved models of CO2-system behavior in freshwater lakes, rivers, soil and sediment pore waters, and physiological fluids. The longer-term benefits of this project will extend to assessments of the influence of ocean acidification on the life cycles of carbonate-bearing organisms that serve as food for economically important marine organisms.</p>
<p>This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.</p>
Spectrophotometric K1K2
largerWorkCitation
project
eng; USA
oceans
1934-01-01
2025-12-31
0
BCO-DMO catalogue of parameters from Boric acid dissociation constants (pKB) from spectrophotometrically calibrated electrode measurements made in natural seawater across estuarine to open-ocean conditions
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
http://lod.bco-dmo.org/id/dataset-parameter/1001632.rdf
Name: source
Units: unitless
Description: <p>The source paper. 'D90' = Dickson (1990) ; 'MMB26' = Martin-Mayor and Byrne (in prep), 'M79' = Millero (1979). See Related Publications for further information about these sources.</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001633.rdf
Name: Target_t_C
Units: degrees Celsius (°C)
Description: <p>target temperature in degrees celsius</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001634.rdf
Name: Target_T_K
Units: Kelvin (K)
Description: <p>target temperature in Kelvin</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001635.rdf
Name: Target_Sal
Units: PSS-78
Description: <p>target practical salinity</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001636.rdf
Name: Temp_C
Units: degrees Celsius (°C)
Description: <p>actual temperature in degrees celsius</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001637.rdf
Name: Temp_K
Units: Kelvin (K)
Description: <p>actual temperature in Kelvin</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001638.rdf
Name: Sal
Units: PSS-78
Description: <p>actual practical salinity</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001639.rdf
Name: exp_pKB_combined
Units: unitless
Description: <p>experimental pKB values</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001640.rdf
Name: borax_added_mg
Units: milligrams (mg)
Description: <p>average amount of sodium tetraborate decahydrate (n=2) added</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001641.rdf
Name: sw_origin
Units: unitless
Description: <p>description of seawater origin</p>
http://lod.bco-dmo.org/id/dataset-parameter/1001642.rdf
Name: sw_collection_year
Units: unitless
Description: <p>Year when the sample was originally collected</p>
GB/NERC/BODC > British Oceanographic Data Centre, Natural Environment Research Council, United Kingdom
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
https://doi.org/10.26008/1912/bco-dmo.1000973.1
download
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dataset
<p>Potentiometric measurements were made using a glass electrode that was spectrophotometrically calibrated following the methods described in Easley and Byrne (2012) and Martell-Bonet and Byrne (2020). The spectrophotometric measurements were made following the guidelines of Clayton and Byrne (1993) and Dickson et al. (2007).</p>
<p>Following the methodology introduced by Byrne and Kester (1974), sodium borate decahydrate (borax) was added to natural seawater at different <em>S</em><sub>P</sub>-<em>T</em> pairs to determine the pH<sub>T</sub> at which the salt addition caused no change in pH<sub>T</sub>. The pH<sub>T</sub> at which the addition of borax causes no change is the p<em>K</em><sub>B</sub> for that specific <em>S</em><sub>P</sub>-<em>T</em> pair. For each <em>S</em><sub>P</sub>-<em>T</em> pair, approximately 15 samples were analyzed. From these, two samples were selected: (1) the sample with the lowest pH<sub>initial</sub> that lowered upon the addition of borax, and (2) the sample with the highest pH<sub>initial</sub> that increased upon the addition of borax. The experimental p<em>K</em><sub>B</sub> (exp-p<em>K</em><sub>B</sub>) for each<em> S</em><sub>P</sub>–<em>T</em> pair was calculated as the mean of the initial and final pH values of the two selected samples; specifically, as the average of pH<sub>initial</sub> for samples (1) and (2) and the average of pH<sub>final</sub> for samples (1) and (2).</p>
Specified by the Principal Investigator(s)
- Imported data from original file "pKB_data_MMB26.xlsx" (sheet 1) into the BCO-DMO system.
- Saved the final file as "1000973_v1_pkb_data_mmb26.csv".
Specified by BCO-DMO Data Managers
asNeeded
7.x-1.1
Biological and Chemical Oceanography Data Management Office (BCO-DMO)
Unavailable
508-289-2009
WHOI MS#36
Woods Hole
MA
02543
USA
info@bco-dmo.org
http://www.bco-dmo.org
Monday - Friday 8:00am - 5:00pm
For questions regarding this resource, please contact BCO-DMO via the email address provided.
pointOfContact
Agilent 8453
Agilent 8453
PI Supplied Instrument Name: Agilent 8453 PI Supplied Instrument Description:All pHT measurements were conducted using a Thermo Scientific Orion ROSS Ultra glass combination pH electrode with BNC connector in the absolute millivolt mode (3 M NaCl filling solution) and a Keithley 6517A Electrometer/High Resistance Meter (0.01 mV resolution). Electrode calibrations were performed using a diode array spectrophotometer (Agilent 8453) with the UV light lamp turned off. Samples were measured in a Teflon open-top custom-made cell holder with a volume of 120mL cleaned regularly with HCl. Instrument Name: Agilent 8453 UV-visible spectrophotometer Instrument Short Name:Agilent 8453 Instrument Description: The Agilent 8453 spectrophotometer is a laboratory optical instrument for chemical analysis to extract spectral information in the ultraviolet (UV) and visible light. The instrument radiates a single light beam by optically combining two source lamps: a deuterium-discharge lamp for the UV wavelength range and a tungsten lamp for the visible and short wave near-infrared (SWNIR) wavelength range. The beam passes through the sample, is focused and dispersed within the spectrograph lens, slit and grating, and reaches the diode array in the form of a spectral image. The diode array samples a wavelength range of 190 to 1100 nm at a mean sampling interval of 0.9 nm. The nominal spectral slit width is 1 nm and the stray light is less than 0.03%.
Ertco-Eutechnics Model 4400
Ertco-Eutechnics Model 4400
PI Supplied Instrument Name: Ertco-Eutechnics Model 4400 PI Supplied Instrument Description:A digital hand-held thermometer (Ertco-Eutechnics Model 4400) with a stainless-steel probe was used to measure the temperature of each sample (±0.025ºC). Instrument Name: digital thermometer Instrument Short Name: Instrument Description: An instrument that measures temperature digitally.
Guildline Portasal 8410A Laboratory Salinometer
Guildline Portasal 8410A Laboratory Salinometer
PI Supplied Instrument Name: Guildline Portasal 8410A Laboratory Salinometer PI Supplied Instrument Description:Seawater salinity was measured with a Guildline Portasal 8410A Laboratory Salinometer. Instrument Name: Guildline Portasal 8410 series salinometer Instrument Short Name:Guildline Portasal 8410 series Instrument Description: The Guildline Portasal 8410 series salinometer is a portable instrument for laboratory or field use that determines salinity of a water sample by comparison of its electrical conductivity with a standard solution. The system employs a continuous flow system, where the sample is drawn into the unit under low air pressure. A high stability temperature control bath and heat exchanger maintain the sample at a precisely defined, user selected temperature during analysis. The instrument can operate over a conductivity range of 0.004 to 76 mS/cm with a resolution of 0.0003 mS/cm (15 deg C and 35 PSU) or 0.0003 Equivalent PSU, and an accuracy of ± 0.003 Equivalent PSU (same set point temperature as standardization and within -2 deg C and +4 deg C of ambient).
The series consists of 2 known models: 8410 and 8410A. The models have the same specifications although the 8410A has an RS232 interface. The reference number 8410N refers to an operational manual update only. Community Standard Description: http://www.osil.co.uk/Products/Ignore/tabid/56/agentType/View/PropertyID/68/Default.aspx
Thermo Scientific Orion ROSS Ultra glass combination pH electrode
Thermo Scientific Orion ROSS Ultra glass combination pH electrode
PI Supplied Instrument Name: Thermo Scientific Orion ROSS Ultra glass combination pH electrode PI Supplied Instrument Description:All pHT measurements were conducted using a Thermo Scientific Orion ROSS Ultra glass combination pH electrode with BNC connector in the absolute millivolt mode (3 M NaCl filling solution) and a Keithley 6517A Electrometer/High Resistance Meter (0.01 mV resolution). Electrode calibrations were performed using a diode array spectrophotometer (Agilent 8453) with the UV light lamp turned off. Samples were measured in a Teflon open-top custom-made cell holder with a volume of 120mL cleaned regularly with HCl. Instrument Name: Thermo Fisher Scientific ORION Ross pH electrode series Instrument Short Name:ORION Ross pH series Instrument Description: A series of pH electrodes that have been in production for over 35 years that are capable of measuring pH in TRIS, protein and sulfide samples. Measurement is based on the degree of potential that develops across a sensing membrane surface when the sensing element comes into contact with a sample. An internal reference electrode provides a second, unvarying potential to quantitatively compare the changes of the sensing membrane potential. This series of electrodes use a Ross Reference System that is based on [I3-/I-] iodide/triiodide ion pair chemistry with platinum wire. The probes typically have 0.01 pH precision.