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
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Chiho Sukigara, Ryuichiro Inoue, Kanako Sato, Yoshihisa Mino, Takeyoshi Nagai, Andrea J. Fassbender, Yuichiro Takeshita, Stuart Bishop, and Eitarou Oka
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Chiho Sukigara, Ryuichiro Inoue, Kanako Sato, Yoshihisa Mino, Takeyoshi Nagai, Andrea J. Fassbender, Yuichiro Takeshita, and Eitarou Oka
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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...
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