Articles | Volume 18, issue 4
https://doi.org/10.5194/bg-18-1407-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-18-1407-2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Technical note
| 
24 Feb 2021
Technical note |
| 24 Feb 2021
| 24 Feb 2021
Technical note: Interpreting pH changes
Andrea J. Fassbender
CORRESPONDING AUTHOR
Monterey Bay Aquarium Research Institute, 7700 Sandholdt Road, Moss
Landing, CA 95039, USA
James C. Orr
LSCE/IPSL, Laboratoire des Sciences du Climat et de l'Environnement,
CEA-CNRS-UVSQ, Gif-sur-Yvette, France
Andrew G. Dickson
Scripps Institution of Oceanography, University of California, San
Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
Related authors
Li-Qing Jiang, Amanda Fay, Jens Daniel Müller, Luke Gregor, Alizée Roobaert, Lydia Keppler, Dustin Carroll, Siv K. Lauvset, Tim DeVries, Judith Hauck, Christian Rödenbeck, Nicolas Metzl, Andrea J. Fassbender, Jean-Pierre Gattuso, Peter Landschützer, Rik Wanninkhof, Christopher Sabine, Simone R. Alin, Mario Hoppema, Are Olsen, Matthew P. Humphreys, Kunal Chakraborty, Ana C. Franco, Kumiko Azetsu-Scott, Dorothee C. E. Bakker, Leticia Barbero, Nicholas R. Bates, Nicole Besemer, Henry C. Bittig, Albert E. Boyd, Daniel Broullón, Wei-Jun Cai, Brendan R. Carter, Thi-Tuyet-Trang Chau, Chen-Tung Arthur Chen, Frédéric Cyr, John E. Dore, Ian Enochs, Richard A. Feely, Hernan E. Garcia, Marion Gehlen, Prasanna Kanti Ghoshal, Lucas Gloege, Melchor González-Dávila, Nicolas Gruber, Debby Ianson, Yosuke Iida, Masao Ishii, Apurva Padamnabh Joshi, Esther Kennedy, Alex Kozyr, Nico Lange, Claire Lo Monaco, Derek P. Manzello, Galen A. McKinley, Natalie M. Monacci, Xose A. Padin, Ana M. Palacio-Castro, Fiz F. Pérez, J. Magdalena Santana-Casiano, Jonathan Sharp, Adrienne Sutton, Jim Swift, Toste Tanhua, Maciej Telszewski, Jens Terhaar, Ruben van Hooidonk, Anton Velo, Andrew J. Watson, Angelicque E. White, Zelun Wu, Liang Xue, Hyelim Yoo, Jiye Zeng, and Guorong Zhong
Earth Syst. Sci. Data, 18, 1405–1462, https://doi.org/10.5194/essd-18-1405-2026, https://doi.org/10.5194/essd-18-1405-2026, 2026
Short summary
Short summary
This review article provides an overview of 68 existing ocean carbonate chemistry data products and data product sets, encompassing a broad range of types, including compilations of cruise datasets, gap-filled observational products, model simulations, and more. It is designed to help researchers identify and access the data products that best support their scientific objectives, thereby facilitating progress in understanding the ocean's changing carbonate chemistry.
Brandon M. Stephens, Montserrat Roca-Martí, Amy E. Maas, Vinícius J. Amaral, Samantha Clevenger, Shawnee Traylor, Claudia R. Benitez-Nelson, Philip W. Boyd, Ken O. Buesseler, Craig A. Carlson, Nicolas Cassar, Margaret Estapa, Andrea J. Fassbender, Yibin Huang, Phoebe J. Lam, Olivier Marchal, Susanne Menden-Deuer, Nicola L. Paul, Alyson E. Santoro, David A. Siegel, and David P. Nicholson
Biogeosciences, 22, 3301–3328, https://doi.org/10.5194/bg-22-3301-2025, https://doi.org/10.5194/bg-22-3301-2025, 2025
Short summary
Short summary
The ocean’s mesopelagic zone (MZ) plays a crucial role in the global carbon cycle. This study combines new and previously published measurements of organic carbon supply and demand collected in August 2018 in the MZ of the subarctic North Pacific Ocean. Supply was insufficient to meet demand in August, but supply entering into the MZ in the spring of 2018 could have met the August demand. Results suggest observations over seasonal timescales may help to close MZ carbon budgets.
Brendan R. Carter, Jörg Schwinger, Rolf Sonnerup, Andrea J. Fassbender, Jonathan D. Sharp, Larissa M. Dias, and Daniel E. Sandborn
Earth Syst. Sci. Data, 17, 3073–3088, https://doi.org/10.5194/essd-17-3073-2025, https://doi.org/10.5194/essd-17-3073-2025, 2025
Short summary
Short summary
We infer ocean gas exchange and circulation from ocean tracer measurements and use this to create code to estimate the amount of carbon dioxide dissolved in the ocean that is there due to human emissions of CO2 into the atmosphere. The code works across the ocean depths for the past, present, or future from information about the location, temperature, and salinity of the seawater. We produce a data product with estimates throughout the ocean throughout the last ~300 and the next ~500 years.
Jonathan D. Sharp, Andrea J. Fassbender, Brendan R. Carter, Gregory C. Johnson, Cristina Schultz, and John P. Dunne
Earth Syst. Sci. Data, 15, 4481–4518, https://doi.org/10.5194/essd-15-4481-2023, https://doi.org/10.5194/essd-15-4481-2023, 2023
Short summary
Short summary
Dissolved oxygen content is a critical metric of ocean health. Recently, expanding fleets of autonomous platforms that measure oxygen in the ocean have produced a wealth of new data. We leverage machine learning to take advantage of this growing global dataset, producing a gridded data product of ocean interior dissolved oxygen at monthly resolution over nearly 2 decades. This work provides novel information for investigations of spatial, seasonal, and interannual variability in ocean oxygen.
Jonathan D. Sharp, Andrea J. Fassbender, Brendan R. Carter, Paige D. Lavin, and Adrienne J. Sutton
Earth Syst. Sci. Data, 14, 2081–2108, https://doi.org/10.5194/essd-14-2081-2022, https://doi.org/10.5194/essd-14-2081-2022, 2022
Short summary
Short summary
Oceanographers calculate the exchange of carbon between the ocean and atmosphere by comparing partial pressures of carbon dioxide (pCO2). Because seawater pCO2 is not measured everywhere at all times, interpolation schemes are required to fill observational gaps. We describe a monthly gap-filled dataset of pCO2 in the northeast Pacific Ocean off the west coast of North America created by machine-learning interpolation. This dataset is unique in its robust representation of coastal seasonality.
Chiho Sukigara, Ryuichiro Inoue, Kanako Sato, Yoshihisa Mino, Takeyoshi Nagai, Andrea J. Fassbender, Yuichiro Takeshita, Stuart Bishop, and Eitarou Oka
Biogeosciences Discuss., https://doi.org/10.5194/bg-2022-9, https://doi.org/10.5194/bg-2022-9, 2022
Manuscript not accepted for further review
Short summary
Short summary
To investigate the physical changes in the ocean from winter to spring and the corresponding biological activities, two automated floats were used to conduct observations in the western North Pacific from January to April 2018. During the observation, repeated storms passed and mixed the ocean surface layer. Afterwards, active biological activity was observed. Using data from the float, we observed the formation, decomposition, and settling of particulate organic matter.
Chiho Sukigara, Ryuichiro Inoue, Kanako Sato, Yoshihisa Mino, Takeyoshi Nagai, Andrea J. Fassbender, Yuichiro Takeshita, and Eitarou Oka
Biogeosciences Discuss., https://doi.org/10.5194/bg-2021-116, https://doi.org/10.5194/bg-2021-116, 2021
Manuscript not accepted for further review
Short summary
Short summary
We combined ship-borne water sampling with the use of two Argo floats equipped with biogeochemical sensors to determine the changes in primary productivity associated with the passage of storms and resultant disturbance in the subtropical western North Pacific. We found that the episodic influx of carbon to the surface facilitated by storms played a key role in promoting primary production. Particulate carbon transported to the twilight layer were not the major substrate for the respiration.
Li-Qing Jiang, Amanda Fay, Jens Daniel Müller, Luke Gregor, Alizée Roobaert, Lydia Keppler, Dustin Carroll, Siv K. Lauvset, Tim DeVries, Judith Hauck, Christian Rödenbeck, Nicolas Metzl, Andrea J. Fassbender, Jean-Pierre Gattuso, Peter Landschützer, Rik Wanninkhof, Christopher Sabine, Simone R. Alin, Mario Hoppema, Are Olsen, Matthew P. Humphreys, Kunal Chakraborty, Ana C. Franco, Kumiko Azetsu-Scott, Dorothee C. E. Bakker, Leticia Barbero, Nicholas R. Bates, Nicole Besemer, Henry C. Bittig, Albert E. Boyd, Daniel Broullón, Wei-Jun Cai, Brendan R. Carter, Thi-Tuyet-Trang Chau, Chen-Tung Arthur Chen, Frédéric Cyr, John E. Dore, Ian Enochs, Richard A. Feely, Hernan E. Garcia, Marion Gehlen, Prasanna Kanti Ghoshal, Lucas Gloege, Melchor González-Dávila, Nicolas Gruber, Debby Ianson, Yosuke Iida, Masao Ishii, Apurva Padamnabh Joshi, Esther Kennedy, Alex Kozyr, Nico Lange, Claire Lo Monaco, Derek P. Manzello, Galen A. McKinley, Natalie M. Monacci, Xose A. Padin, Ana M. Palacio-Castro, Fiz F. Pérez, J. Magdalena Santana-Casiano, Jonathan Sharp, Adrienne Sutton, Jim Swift, Toste Tanhua, Maciej Telszewski, Jens Terhaar, Ruben van Hooidonk, Anton Velo, Andrew J. Watson, Angelicque E. White, Zelun Wu, Liang Xue, Hyelim Yoo, Jiye Zeng, and Guorong Zhong
Earth Syst. Sci. Data, 18, 1405–1462, https://doi.org/10.5194/essd-18-1405-2026, https://doi.org/10.5194/essd-18-1405-2026, 2026
Short summary
Short summary
This review article provides an overview of 68 existing ocean carbonate chemistry data products and data product sets, encompassing a broad range of types, including compilations of cruise datasets, gap-filled observational products, model simulations, and more. It is designed to help researchers identify and access the data products that best support their scientific objectives, thereby facilitating progress in understanding the ocean's changing carbonate chemistry.
Jeanne Dombret, Hugo Bellenger, Xavier Perrot, Laëtitia Parc, Lester Kwiatkowski, Frédéric Chevallier, Laurent Bopp, Marion Gehlen, Roland Séférian, Sarah Berthet, and James C. Orr
EGUsphere, https://doi.org/10.22541/essoar.175308893.36793607/v1, https://doi.org/10.22541/essoar.175308893.36793607/v1, 2025
Short summary
Short summary
Estimates of ocean CO2 uptake based on atmospheric and oceanic observations typically rely on monthly averages, except for wind speed. Thus they neglect effects of shorter-term events such as storms, which are included in models. Here we account for the effect of this shorter-term variability on ocean carbon uptake and find that it is reduced, mainly because storms lower atmospheric pressure. This refinement closes the gap between data-based and model-based estimates by 25 %.
Brandon M. Stephens, Montserrat Roca-Martí, Amy E. Maas, Vinícius J. Amaral, Samantha Clevenger, Shawnee Traylor, Claudia R. Benitez-Nelson, Philip W. Boyd, Ken O. Buesseler, Craig A. Carlson, Nicolas Cassar, Margaret Estapa, Andrea J. Fassbender, Yibin Huang, Phoebe J. Lam, Olivier Marchal, Susanne Menden-Deuer, Nicola L. Paul, Alyson E. Santoro, David A. Siegel, and David P. Nicholson
Biogeosciences, 22, 3301–3328, https://doi.org/10.5194/bg-22-3301-2025, https://doi.org/10.5194/bg-22-3301-2025, 2025
Short summary
Short summary
The ocean’s mesopelagic zone (MZ) plays a crucial role in the global carbon cycle. This study combines new and previously published measurements of organic carbon supply and demand collected in August 2018 in the MZ of the subarctic North Pacific Ocean. Supply was insufficient to meet demand in August, but supply entering into the MZ in the spring of 2018 could have met the August demand. Results suggest observations over seasonal timescales may help to close MZ carbon budgets.
Brendan R. Carter, Jörg Schwinger, Rolf Sonnerup, Andrea J. Fassbender, Jonathan D. Sharp, Larissa M. Dias, and Daniel E. Sandborn
Earth Syst. Sci. Data, 17, 3073–3088, https://doi.org/10.5194/essd-17-3073-2025, https://doi.org/10.5194/essd-17-3073-2025, 2025
Short summary
Short summary
We infer ocean gas exchange and circulation from ocean tracer measurements and use this to create code to estimate the amount of carbon dioxide dissolved in the ocean that is there due to human emissions of CO2 into the atmosphere. The code works across the ocean depths for the past, present, or future from information about the location, temperature, and salinity of the seawater. We produce a data product with estimates throughout the ocean throughout the last ~300 and the next ~500 years.
Nina Bednaršek, Hanna van de Mortel, Greg Pelletier, Marisol García-Reyes, Richard A. Feely, and Andrew G. Dickson
Biogeosciences, 22, 473–498, https://doi.org/10.5194/bg-22-473-2025, https://doi.org/10.5194/bg-22-473-2025, 2025
Short summary
Short summary
The environmental impacts of ocean alkalinity enhancement (OAE) are unknown. Our synthesis, based on 68 collected studies with 84 unique species, shows that 35 % of species respond positively, 26 % respond negatively, and 39 % show a neutral response to alkalinity addition. Biological thresholds were found from 50 to 500 µmol kg−1 NaOH addition. A precautionary approach is warranted to avoid potential risks, while current regulatory framework needs improvements to assure safe biological limits.
Kai G. Schulz, Lennart T. Bach, and Andrew G. Dickson
State Planet, 2-oae2023, 2, https://doi.org/10.5194/sp-2-oae2023-2-2023, https://doi.org/10.5194/sp-2-oae2023-2-2023, 2023
Short summary
Short summary
Ocean alkalinity enhancement is a promising approach for long-term anthropogenic carbon dioxide sequestration, required to avoid catastrophic climate change. In this chapter we describe its impacts on seawater carbonate chemistry speciation and highlight pitfalls that need to be avoided during sampling, storage, measurements, and calculations.
Jonathan D. Sharp, Andrea J. Fassbender, Brendan R. Carter, Gregory C. Johnson, Cristina Schultz, and John P. Dunne
Earth Syst. Sci. Data, 15, 4481–4518, https://doi.org/10.5194/essd-15-4481-2023, https://doi.org/10.5194/essd-15-4481-2023, 2023
Short summary
Short summary
Dissolved oxygen content is a critical metric of ocean health. Recently, expanding fleets of autonomous platforms that measure oxygen in the ocean have produced a wealth of new data. We leverage machine learning to take advantage of this growing global dataset, producing a gridded data product of ocean interior dissolved oxygen at monthly resolution over nearly 2 decades. This work provides novel information for investigations of spatial, seasonal, and interannual variability in ocean oxygen.
Jonathan D. Sharp, Andrea J. Fassbender, Brendan R. Carter, Paige D. Lavin, and Adrienne J. Sutton
Earth Syst. Sci. Data, 14, 2081–2108, https://doi.org/10.5194/essd-14-2081-2022, https://doi.org/10.5194/essd-14-2081-2022, 2022
Short summary
Short summary
Oceanographers calculate the exchange of carbon between the ocean and atmosphere by comparing partial pressures of carbon dioxide (pCO2). Because seawater pCO2 is not measured everywhere at all times, interpolation schemes are required to fill observational gaps. We describe a monthly gap-filled dataset of pCO2 in the northeast Pacific Ocean off the west coast of North America created by machine-learning interpolation. This dataset is unique in its robust representation of coastal seasonality.
Chiho Sukigara, Ryuichiro Inoue, Kanako Sato, Yoshihisa Mino, Takeyoshi Nagai, Andrea J. Fassbender, Yuichiro Takeshita, Stuart Bishop, and Eitarou Oka
Biogeosciences Discuss., https://doi.org/10.5194/bg-2022-9, https://doi.org/10.5194/bg-2022-9, 2022
Manuscript not accepted for further review
Short summary
Short summary
To investigate the physical changes in the ocean from winter to spring and the corresponding biological activities, two automated floats were used to conduct observations in the western North Pacific from January to April 2018. During the observation, repeated storms passed and mixed the ocean surface layer. Afterwards, active biological activity was observed. Using data from the float, we observed the formation, decomposition, and settling of particulate organic matter.
Chiho Sukigara, Ryuichiro Inoue, Kanako Sato, Yoshihisa Mino, Takeyoshi Nagai, Andrea J. Fassbender, Yuichiro Takeshita, and Eitarou Oka
Biogeosciences Discuss., https://doi.org/10.5194/bg-2021-116, https://doi.org/10.5194/bg-2021-116, 2021
Manuscript not accepted for further review
Short summary
Short summary
We combined ship-borne water sampling with the use of two Argo floats equipped with biogeochemical sensors to determine the changes in primary productivity associated with the passage of storms and resultant disturbance in the subtropical western North Pacific. We found that the episodic influx of carbon to the surface facilitated by storms played a key role in promoting primary production. Particulate carbon transported to the twilight layer were not the major substrate for the respiration.
Cited articles
Archer, D. E., Kheshgi, H., and Maier-Reimer, E.: Dynamics of fossil fuel
CO2 neutralization by marine CaCO3, Global Biogeochem. Cy.,
12, 259–276, https://doi.org/10.1029/98GB00744, 1998.
Bates, N., Astor, Y., Church, M. J., Currie, K., Dore, J.,
Gonaález-Dávila, M., Lorenzoni, L., Muller-Karger, F., Olafsson, J.,
and Santana-Casiano, J. M.: A time-series view of changing ocean chemistry
due to ocean uptake of anthropogenic CO2 and ocean acidification,
Oceanography, 27, 126–141, https://doi.org/10.5670/oceanog.2014.16, 2014.
Bates, R. G.: pH measurements in the marine environment, Pure Appl. Chem.,
54, 229–232, https://doi.org/10.1351/pac198254010229, 1982.
Bates, R. G. and Guggenheim, E. A.: Report on the standardization of pH and
related terminology, Pure Appl. Chem., 1, 163–168,
https://doi.org/10.1351/pac196001010163, 1960.
Baucke, F. G. K.: New IUPAC recommendations on the measurement of pH – background
and essentials, Anal. Bioanal. Chem., 374, 772–777,
https://doi.org/10.1007/s00216-002-1523-4, 2002.
Bopp, L., Resplandy, L., Orr, J. C., Doney, S. C., Dunne, J. P., Gehlen, M., Halloran, P., Heinze, C., Ilyina, T., Séférian, R., Tjiputra, J., and Vichi, M.: Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models, Biogeosciences, 10, 6225–6245, https://doi.org/10.5194/bg-10-6225-2013, 2013.
Boudreau, B. P., Middelburg, J. J., and Luo, Y.: The role of calcification in
carbonate compensation, Nat. Geosci., 11, 894–900,
https://doi.org/10.1038/s41561-018-0259-5, 2018.
Boyd, P. W., Cornwall, C. E., Davison, A., Doney, S. C., Fourquez, M., Hurd,
C. L., Lima, I. D., and McMinn, A.: Biological responses to environmental
heterogeneity under future ocean conditions, Global Change Biol., 22, 2633–2650, https://doi.org/10.1111/gcb.13287, 2016.
Brewer, P. G.: A short history of ocean acidification science in the 20th century: a chemist's view, Biogeosciences, 10, 7411–7422, https://doi.org/10.5194/bg-10-7411-2013, 2013.
Buck, R. P., Rondinini, S., Covington, A. K., Baucke, F. G. K., Brett, C. M.
A., Camoes, M. F., Milton, M. J. T., Mussini, T., Naumann, R., Pratt, K. W.,
Spitzer, P., and Wilson, G. S.: Measurement of pH, Definition, standards, and
procedures (IUPAC Recommendations 2002), Pure Appl. Chem., 74,
2169–2200, https://doi.org/10.1351/pac200274112169, 2002.
Bushinsky, S. M., Takeshita, Y., and Williams, N. L.: Observing changes in
ocean carbonate chemistry: our autonomous future,
Curr. Clim. Change Reports, 5, 207–220, https://doi.org/10.1007/s40641-019-00129-8, 2019.
Caldeira, K. and Wickett, M. E.: Anthropogenic carbon and ocean pH, Nature,
425, 365, https://doi.org/10.1038/425365a, 2003.
Carstensen, J. and Duarte, C. M.: Drivers of pH Variability in Coastal
Ecosystems, Environ. Sci. Technol., 53, 4020–4029,
https://doi.org/10.1021/acs.est.8b03655, 2019.
Carter, B. R., Feely, R. A., Wanninkhof, R., Kouketsu, S., Sonnerup, R. E.,
Pardo, P. C., Sabine, C. L., Johnson, G. C., Sloyan, B. M., Murata, A.,
Mecking, S., Tilbrook, B., Speer, K., Talley, L. D., Millero, F. J.,
Wijffels, S. E., Macdonald, A. M., Gruber, N., and Bullister, J. L.: Pacific
anthropogenic carbon between 1991 and 2017, Global Biogeochem. Cy., 33, 597–617,
https://doi.org/10.1029/2018GB006154, 2019.
Chen, C.-T. A., Lui, H.-K., Hsieh, C.-H., Yanagi, T., Kosugi, N., Ishii, M.,
and Gong, G.-C.: Deep oceans may acidify faster than anticipated due to
global warming, Nat. Clim. Change, 7, 890–894,
https://doi.org/10.1038/s41558-017-0003-y, 2017.
Chu, S. N., Wang, Z. A., Doney, S. C., Lawson, G. L., and Hoering, K. A.:
Changes in anthropogenic carbon storage in the Northeast Pacific in the last
decade, J. Geophys. Res.-Oceans, 121, 4618–4632,
https://doi.org/10.1002/2016JC011775, 2016.
Clark, W. M.: The determination of hydrogen ions, edn. 2, Williams and
Wilkins Company, Baltimore, Maryland, USA, 480 pp., 1922.
Clark, W. M., Wherry, E. T., and Adams, E. Q.: Reply to Wherry and Adams'
article on methods of stating acidity,
J. Washingt. Acad. Sci., 11, 199–202, available at: https://www.jstor.org/stable/24532479 (last access: 1 February 2021), 1921.
Cohen, E. R., Cvitas, T., Frey, J. G., Holström, B., Kuchitsu, K., Marquardt, R., Mills, I., Pavese, F., Quack, M., Stohner, J., Strauss, H. L., Takami, M., and Thor, A. J.: Quantities, Units and Symbols in Physical Chemistry, Third Edit., edited by: Cohen, E. R., Cvitas, T., Frey, J. G., Holström, B., Kuchitsu, K., Marquardt, R., Mills, I., Pavese, F., Quack, M., Stohner, J., Strauss, H. L., Takami, M., and Thor, A. J., Royal Society of Chemistry, Cambridge, 1–250, 2007.
Covington, A. K., Bates, R. G., and Durst, R. A.: Definition of pH scales,
standard reference values, measurement of pH and related terminology
(recommendations 1984), available at:
http://publications.iupac.org/pac/1985/pdf/5703x0531.pdf (last access: 15 January 2021), 1985.
Dickson, A. G.: pH scales and proton-transfer reactions in saline media such
as sea water, Geochim. Cosmochim. Ac., 48, 2299–2308,
https://doi.org/10.1016/0016-7037(84)90225-4, 1984.
Dickson, A. G.: Standard potential of the reaction: AgCl(s) +
Dickson, A. G.: Seawater carbonate chemistry, Part I, in: Guide to best
practices for ocean acidification research and data reporting, edited by:
Riebesell, U., Fabry, V. J., Hansson, L., and Gattuso, J. P., European Commission, Brussels, Belgium, 17–40, 2010.
Dickson, A. G., Camões, M. F., Spitzer, P., Fisicaro, P., Stoica, D.,
Pawlowicz, R., and Feistel, R.: Metrological challenges for measurements of
key climatological observables, Part 3: seawater pH, Metrologia, 53,
R26–R39, https://doi.org/10.1088/0026-1394/53/1/R26, 2016.
Doney, S. C., Fabry, V. J., Feely, R. A., and Kleypas, J. A.: Ocean
acidification: the other CO2 problem, Annu. Rev. Mar. Sci., 1,
169–192, https://doi.org/10.1146/annurev.marine.010908.163834, 2009.
Doney, S. C., Bopp, L., and Long, M.: Historical and future trends in ocean
climate and biogeochemistry, Oceanography, 27, 108–119,
https://doi.org/10.5670/oceanog.2014.14, 2014.
Dore, J., Lukas, R., Sadler, D. W., Church, M. J., and Karl, D. M.: Physical
and biogeochemical modulation of ocean acidification in the central North
Pacific, P. Natl. Acad. Sci. USA, 106, 12235–12240, https://doi.org/10.1073/pnas.0906044106, 2009.
Dunne, J. P., John, J. G., Adcroft, A. J., Griffies, S. M., Hallberg, R. W.,
Shevliakova, E., Stouffer, R. J., Cooke, W., Dunne, K. A., Harrison, M. J.,
Krasting, J. P., Malyshev, S. L., Milly, P. C. D., Phillipps, P. J.,
Sentman, L. T., Samuels, B. L., Spelman, M. J., Winton, M., Wittenberg, A.
T., and Zadeh, N.: GFDL's ESM2 global coupled climate–carbon Earth System
Models, Part I: physical formulation and baseline simulation
characteristics, J. Climate, 25, 6646–6665,
https://doi.org/10.1175/JCLI-D-11-00560.1, 2012.
Dunne, J. P., John, J. G., Shevliakova, E., Stouffer, R. J., Krasting, J.
P., Malyshev, S. L., Milly, P. C. D., Sentman, L. T., Adcroft, A. J., Cooke,
W., Dunne, K. A., Griffies, S. M., Hallberg, R. W., Harrison, M. J., Levy,
H., Wittenberg, A. T., Phillips, P. J., and Zadeh, N.: GFDL's ESM2 global
coupled climate–carbon Earth System Models, Part II: carbon system
formulation and baseline simulation characteristics, J. Climate, 26,
2247–2267, https://doi.org/10.1175/JCLI-D-12-00150.1, 2013.
Fassbender, A. J., Sabine, C. L., and Palevsky, H. I.: Nonuniform ocean
acidification and attenuation of the ocean carbon sink, Geophys. Res. Lett.,
44, 8404–8413, https://doi.org/10.1002/2017GL074389, 2017.
GCOS: The Global Observing System for climate: implementation needs,
available at: https://library.wmo.int/doc_num.php?explnum_id=3417 (last access: 23 September 2020), 2016.
GOOS: Essential Ocean Variables, available at:
http://www.goosocean.org/index.php?option=com_content&view=article&id=14&Itemid=114, last access: 1 August 2019.
Hales, B., Suhrbier, A., Waldbusser, G. G., Feely, R. A., and Newton, J. A.:
The Carbonate Chemistry of the “Fattening Line”, Willapa Bay, 2011–2014,
Estuar. Coast., 40, 173–186, https://doi.org/10.1007/s12237-016-0136-7, 2017.
Hamer, W. J. and Acree, S. F.: Primary pH measurements and standards,
J. Res. Natl. Bur. Stand., 23, 647–657, 1939.
Hofmann, G. E., Barry, J. P., Edmunds, P. J., Gates, R. D., Hutchins, D. A.,
Klinger, T., and Sewell, M. A.: The effect of ocean acidification on
calcifying organisms in marine ecosystems: an organism-to-ecosystem
perspective, Annu. Rev. Ecol. Evol. S., 41, 127–147,
https://doi.org/10.1146/annurev.ecolsys.110308.120227, 2010.
Hofmann, G. E., Smith, J. E., Johnson, K. S., Send, U., Levin, L. A.,
Micheli, F., Paytan, A., Price, N. N., Peterson, B., Takeshita, Y., Matson,
P. G., Crook, E. D., Kroeker, K. J., Gambi, M. C., Rivest, E. B., Frieder,
C. A., Yu, P. C., and Martz, T. R.: High-frequency dynamics of ocean pH: a
multi-ecosystem comparison, PLoS One, 6, e28983,
https://doi.org/10.1371/journal.pone.0028983, 2011.
Jiang, L.-Q., Carter, B. R., Feely, R. A., Lauvset, S. K., and Olsen, A.:
Surface ocean pH and buffer capacity: past, present and future, Sci. Rep.,
9, 18624, https://doi.org/10.1038/s41598-019-55039-4, 2019.
Kapsenberg, L. and Cyronak, T.: Ocean acidification refugia in variable
environments, Global Change Biol., 25, 3201–3214, https://doi.org/10.1111/gcb.14730,
2019.
Kleypas, J. A., Feely, R. A., Fabry, V. J., Langdon, C., Sabine, C. L., and
Robbins, L. L.: Impacts of ocean acidification on coral reefs and other marine
calcifiers: a guide for future research, report of a workshop held 18–20 April 2005, St. Petersburg, FL, sponsored by NSF, NOAA, and the U.S. Geological Survey, 88 pp., 2006.
Kwiatkowski, L. and Orr, J. C.: Diverging seasonal extremes for ocean
acidification during the twenty-first century, Nat. Clim. Change, 8,
141–145, https://doi.org/10.1038/s41558-017-0054-0, 2018.
Kwiatkowski, L., Torres, O., Bopp, L., Aumont, O., Chamberlain, M., Christian, J. R., Dunne, J. P., Gehlen, M., Ilyina, T., John, J. G., Lenton, A., Li, H., Lovenduski, N. S., Orr, J. C., Palmieri, J., Santana-Falcón, Y., Schwinger, J., Séférian, R., Stock, C. A., Tagliabue, A., Takano, Y., Tjiputra, J., Toyama, K., Tsujino, H., Watanabe, M., Yamamoto, A., Yool, A., and Ziehn, T.: Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections, Biogeosciences, 17, 3439–3470, https://doi.org/10.5194/bg-17-3439-2020, 2020.
Lauvset, S. K., Gruber, N., Landschützer, P., Olsen, A., and Tjiputra, J.: Trends and drivers in global surface ocean pH over the past 3 decades, Biogeosciences, 12, 1285–1298, https://doi.org/10.5194/bg-12-1285-2015, 2015.
Lauvset, S. K., Key, R. M., Olsen, A., van Heuven, S., Velo, A., Lin, X., Schirnick, C., Kozyr, A., Tanhua, T., Hoppema, M., Jutterström, S., Steinfeldt, R., Jeansson, E., Ishii, M., Perez, F. F., Suzuki, T., and Watelet, S.: A new global interior ocean mapped climatology: the 1∘ × 1∘ GLODAP version 2, Earth Syst. Sci. Data, 8, 325–340, https://doi.org/10.5194/essd-8-325-2016, 2016.
Lauvset, S. K., Carter, B. R., Pèrez, F. F., Jiang, L.-Q., Feely, R.
A., Velo, A., and Olsen, A.: Processes driving global interior ocean pH
distribution, Global Biogeochem. Cy., 34, 1–17,
https://doi.org/10.1029/2019GB006229, 2020.
Lewis, E. and Wallace, D. W. R.: Program developed for CO2 system
calculations, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, Tennessee, USA, 4735,
available at:
https://www.nodc.noaa.gov/ocads/oceans/CO2SYS/co2rprt.html (last access: 2 July 2014), 1998.
Lueker, T. J., Dickson, A. G., and Keeling, C. D.: Ocean pCO2 calculated from dissolved inorganic carbon, alkalinity, and equations for K1 and
K2: validation based on laboratory measurements of CO2 in gas and
seawater at equilibrium, Mar. Chem., 70, 105–119,
https://doi.org/10.1016/S0304-4203(00)00022-0, 2000.
Marion, G. M., Millero, F. J., Camões, M. F., Spitzer, P., Feistel, R.,
and Chen, C.-T. A.: pH of seawater, Mar. Chem., 126, 89–96,
https://doi.org/10.1016/j.marchem.2011.04.002, 2011.
McGlashan, M. L.: Manual of symbols and terminology for physicochemical
quantities and units, Pure Appl. Chem., 21, 1–38, 1970.
McNeil, B. I. and Sasse, T. P.: Future ocean hypercapnia driven by
anthropogenic amplification of the natural CO2 cycle, Nature,
529, 383–386, https://doi.org/10.1038/nature16156, 2016.
Millero, F. J.: The marine inorganic carbon cycle, Chem. Rev., 107,
308–341, https://doi.org/10.1021/cr0503557, 2007.
Munro, D. R., Lovenduski, N. S., Takahashi, T., Stephens, B. B., Newberger,
T., and Sweeney, C.: Recent evidence for a strengthening CO2 sink in the
Southern Ocean from carbonate system measurements in the Drake Passage
(2002–2015), Geophys. Res. Lett., 42, 7623–7630,
https://doi.org/10.1002/2015GL065194, 2015.
Orr, J. C., Fabry, V. J., Aumont, O., Bopp, L., Doney, S. C., Feely, R. A.,
Gnanadesikan, A., Gruber, N., Ishida, A., Joos, F., Key, R. M., Lindsay, K.,
Maier-Reimer, E., Matear, R., Monfray, P., Mouchet, A., Najjar, R. G.,
Plattner, G.-K., Rodgers, K. B., Sabine, C. L., Sarmiento, J. L., Schlitzer,
R., Slater, R. D., Totterdell, I. J., Weirig, M.-F., Yamanaka, Y., and Yool,
A.: Anthropogenic ocean acidification over the twenty-first century and its
impact on calcifying organisms, Nature, 437, 681–686,
https://doi.org/10.1038/nature04095, 2005.
Orr, J. C., Epitalon, J.-M., and Gattuso, J.-P.: Comparison of ten packages that compute ocean carbonate chemistry, Biogeosciences, 12, 1483–1510, https://doi.org/10.5194/bg-12-1483-2015, 2015.
Passow, U. and Carlson, C. A.: The biological pump in a high CO2 world,
Mar. Ecol. Prog. Ser., 470, 249–271, https://doi.org/10.3354/meps09985, 2012.
Resplandy, L., Bopp, L., Orr, J. C., and Dunne, J. P.: Role of mode and
intermediate waters in future ocean acidification: Analysis of CMIP5 models,
Geophys. Res. Lett., 40, 3091–3095, https://doi.org/10.1002/grl.50414, 2013.
Revelle, R. and Suess, H. E.: Carbon dioxide exchange between atmosphere and
ocean and the question of an increase of atmospheric CO2 during the
past decades, Tellus, 9, 18–27, https://doi.org/10.1111/j.2153-3490.1957.tb01849.x,
1957.
Rhein, M., Rintoul, S. R., Aoki, S., Campos, E., Chambers, D., Feely, R. A., Gulev, S., Johnson, G. C., Josey, S. A., Kostianoy, A., Mauritzen, C., Roemmich, D., Talley, L. D., and Wang, F.: Observations: Ocean. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Stocker, T. F., Qin, D., Plattner, G.-K., Tignor, M., Allen, S. K., Boschung, J., Nauels, A., Xia, Y., Bex, V., and Midgley, P. M., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, 2013.
Riahi, K., Rao, S., Krey, V., Cho, C., Chirkov, V., Fischer, G., Kindermann,
G., Nakicenovic, N., and Rafaj, P.: RCP 8.5 – A scenario of comparatively
high greenhouse gas emissions, Climatic Change, 109, 33–57,
https://doi.org/10.1007/s10584-011-0149-y, 2011.
Ríos, A. F., Resplandy, L., García-Ibáñez, M. I., Fajar,
N. M., Velo, A., Padín, X. A., Wanninkhof, R., Steinfeldt, R.,
Rosón, G., Pérez, F. F., and Morel, F. M. M.: Decadal acidification
in the water masses of the Atlantic Ocean, P. Natl. Acad. Sci. USA,
112, 9950–9955, https://doi.org/10.1073/pnas.1504613112, 2015.
Sørensen, S. P. L.: Enzymstudien II: Über die Messung und Bedeutung
der Wasserstoffionen-konzentration bei biologischen Prozessen,
Biochem. Z., 21, 131–200, https://doi.org/10.1007/BF02325444, 1909.
Sørensen, S. P. L. and Linderstrøm-Lang, K.: On the determination and value
of po in electrometric measurements of hydrogen ion concentrations, Compt. rend. trav. lab. Carlsberg, 15, 1–40, 1924.
Spitzer, P. and Pratt, K. W.: The history and development of a rigorous
metrological basis for pH measurements, J. Solid State Electr., 15,
69–76, https://doi.org/10.1007/s10008-010-1106-9, 2011.
Steinacher, M., Joos, F., Frölicher, T. L., Plattner, G.-K., and Doney, S. C.: Imminent ocean acidification in the Arctic projected with the NCAR global coupled carbon cycle-climate model, Biogeosciences, 6, 515–533, https://doi.org/10.5194/bg-6-515-2009, 2009.
Sutton, A. J., Feely, R. A., Sabine, C. L., McPhaden, M. J., Takahashi, T.,
Chavez, F. P., Friederich, G. E., and Mathis, J. T.: Natural variability and
anthropogenic change in equatorial Pacific surface ocean pCO2 and pH,
Global Biogeochem. Cy., 28, 131–145, https://doi.org/10.1002/2013GB004679, 2014.
Takahashi, T., Sutherland, S. C., Chipman, D. W., Goddard, J. G., and Ho, C.:
Climatological distributions of pH, pCO2, total CO2, alkalinity,
and CaCO3 saturation in the global surface ocean, and temporal changes
at selected locations, Mar. Chem., 164, 95–125,
https://doi.org/10.1016/j.marchem.2014.06.004, 2014.
Thyng, K., Greene, C., Hetland, R., Zimmerle, H., and DiMarco, S.: True
Colors of Oceanography: Guidelines for Effective and Accurate Colormap
Selection, Oceanography, 29, 9–13, https://doi.org/10.5670/oceanog.2016.66, 2016.
Uppström, L. R.: The boron-chlorinity ratio of deep seawater from the
Pacific Ocean, Deep. Res. Part I, 21, 161–162, 1974.
van Heuven, S. M. A. C., Pierrot, D., Rae, J. W. B., Lewis, E., and Wallace,
D. W. R.: MATLAB program developed for CO2 system calculations,
ORNL/CDIAC-105b, Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, US Department of Energy, Oak Ridge, Tennessee, USA, https://www.ncei.noaa.gov/access/ocean-carbon-data-system/oceans/CO2SYS/co2rprt.html, 2011.
Waters, J. F. and Millero, F. J.: The free proton concentration scale for
seawater pH, Mar. Chem., 149, 8–22, https://doi.org/10.1016/j.marchem.2012.11.003,
2013.
IPCC: Annex I: Glossary, edited by: Weyer, N. M., in: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate, edited by: Pörtner, H.-O., Roberts, D. C., Masson-Delmotte, V., Zhai, P., Tignor, M., Poloczanska, E., Mintenbeck, K., Alegría, A., Nicolai, M., Okem, A., Petzold, J., Rama, B., and Weyer N. M., in press, 2019.
Wherry, E. T.: The statement of acidity and alkalinity, with special
reference to soils, J. Washingt. Acad. Sci., 9, 305–309, available at: https://www.jstor.org/stable/24521412 (last access: 23 September 2020), 1919.
Wherry, E. T. and Adams, E. Q.: Methods of stating acidity, J. Washingt.
Acad. Sci., 11, 197–199, available at:
https://www.jstor.org/stable/24532477 (last access: 23 September 2020), 1921.
Williams, N. L., Feely, R. A., Sabine, C. L., Dickson, A. G., Swift, J. H.,
Talley, L. D., and Russell, J. L.: Quantifying anthropogenic carbon inventory
changes in the Pacific sector of the Southern Ocean, Mar. Chem., 174,
147–160, https://doi.org/10.1016/j.marchem.2015.06.015, 2015.
Woosley, R. J., Millero, F. J., and Wanninkhof, R.: Rapid anthropogenic
changes in CO2 and pH in the Atlantic Ocean: 2003–2014, Global Biogeochem. Cy., 30, 70–90, https://doi.org/10.1002/2015GB005248, 2016.
Short summary
A decline in upper-ocean pH with time is typically ascribed to ocean acidification. A more quantitative interpretation is often confused by failing to recognize the implications of pH being a logarithmic transform of hydrogen ion concentration rather than an absolute measure. This can lead to an unwitting misinterpretation of pH data. We provide three real-world examples illustrating this and recommend the reporting of both hydrogen ion concentration and pH in studies of ocean chemical change.
A decline in upper-ocean pH with time is typically ascribed to ocean acidification. A more...
Altmetrics
Final-revised paper
Preprint