[en] Along with other carbon monitoring groups, the ocean acidification (OA) community has been observing, modeling, and projecting the impacts of changing carbonate chemistry for over two decades. The Global Ocean Acidification Observing Network (GOA-ON) has three key goals related to these issues: (1) improve understanding of global OA conditions, (2) improve understanding of ecosystem responses to OA, and (3) acquire and exchange data necessary to optimize modeling for OA and its impacts. GOA-ON and associated networks have a wealth of knowledge, data, models, and best practice guides on how to monitor global carbonate chemistry, and GOA-ON regional hubs collaborate at local scales to inform policy and action for coastal communities. Here, the GOA-ON community shares lessons learned relevant for marine carbon dioxide removal (mCDR) research and development. Understanding whether, how, and where mCDR approaches should be deployed will require knowledge of the carbonate system, robust observations, sensor technology, and modeling capacities. Ongoing monitoring, reporting, and verification during field trials and any eventual implementation of mCDR will again require these resources. The GOA-ON community’s knowledge about environmental impacts, running laboratory and field experiments, and deriving biological indicators of change is of fundamental importance for assessing the environmental impacts of mCDR and of the potential for mitigating or exacerbating OA. Finally, we present recommendations for utilizing this OA experience toward mCDR research.
Disciplines :
Environmental sciences & ecology
Author, co-author :
Findlay, Helen S.; Plymouth Marine Laboratory, Plymouth, United Kingdom
Feely, Richard A.; NOAA Pacific Marine Environmental Laboratory, Seattle, United States
Grabb, Kalina; IBSS, under contract in support of NOAA Northeast Fisheries Science Center, Woods Hole, United States
Jewett, Elizabeth B.; NOAA Northeast Fisheries Science Center, Woods Hole, United States
Keister, Elise F.; NOAA Ocean Acidification Program, United States
Kitch, Gabby; NOAA Ocean Acidification Program, United States
Artioli, Yuri; Plymouth Marine Laboratory, Plymouth, United Kingdom
Bhadury, Punyasloke; Centre for Climate and Environmental Studies, Indian Institute of Science Education and Research Kolkata, Moahnpur, India
Blackford, Jeremy; Plymouth Marine Laboratory, Plymouth, United Kingdom
Crabeck, Odile ; Université de Liège - ULiège > Département d'astrophysique, géophysique et océanographie (AGO)
Ghosh, Anwesha; Centre for Climate and Environmental Studies, Indian Institute of Science Education and Research Kolkata, Moahnpur, India
Li, Yaru; Plymouth Marine Laboratory, Plymouth, United Kingdom
Lowder, Kaitlyn B.; The Ocean Foundation, Washington, United States
Mehta, Shreya; Geosciences Division, Physical Research Laboratory, Ahmedabad, India
Van Dam, Bryce; Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, Germany
Beghoura, Houda; Geophysical Institute, University of Bergen, Bjerknes Centre for Climate Research, Bergen, Norway
Karo, Noam; Schulich Faculty of Chemistry, Resnick Sustainability Center for Catalysis, The Nancy & Stephen Grand Technion Energy Program (GTEP), Technion-Israel Institute of Technology, Haifa, Israel
Horodysky, Andrij Z.; James J. Howard Laboratory, NOAA Northeast Fisheries Science Center, Highlands, United States
Hennige, Sebastian; School of GeoSciences, University of Edinburgh, United Kingdom
Salaah, Sally M.; National Institute of Oceanography and Fisheries, Cairo, Egypt
Ragazzola, Federica; Genoa Marine Center-Stazione Zoologica Anton Dohrn, Genoa, Italy
Wright-Fairbanks, Liza; University Corporation for Atmospheric Research, NOAA Ocean Acidification Program, United States
We thank the GOA-ON executive council members for reviewing this work and all participants of the GOA-ON mCDR webinar held online on April 16, 2024. We also thank the NOAA Ocean Acidification Program, the IAEA OA-ICC, and the IOC-UNESCO for supporting the GOA-ON mCDR working group. HSF acknowledges funding from a Natural Environment Research Council grant, NE/X006271/1. HB was supported by the European Union under grant agreement no. 101094690 (EuroGO-SHIP). RAF was funded by NOAA\u2019s National Centers for Coastal Ocean Science Competitive Research Program, Climate Program Office, Ocean Acidification Program (OAP) and the US Integrated Ocean Observing System Office under award NA22NOS4780171 to Oregon State University and NOAA\u2019s Pacific Marine Environmental Laboratory, and by NOAA\u2019s OAP (NA210AR4310251).Richard A. Feely, NOAA Pacific Marine Environmental Laboratory, Seattle, WA, USA. Kalina Grabb, IBSS, under contract in support of NOAA Northeast Fisheries Science Center, Woods Hole, MA, USA. Elizabeth B. Jewett, NOAA Northeast Fisheries Science Center, Woods Hole, MA, USA. Elise F. Keister and Gabby Kitch, NOAA Ocean Acidification Program, Silver Spring, MD, USA. Yuri Artioli, Plymouth Marine Laboratory, Plymouth, UK. Punyasloke Bhadury, Centre for Climate and Environmental Studies, Indian Institute of Science Education and Research Kolkata, Moahnpur, Nadia, West Bengal, India. Jeremy Blackford, Plymouth Marine Laboratory, Plymouth, UK. Odile Crabeck, Chemical Oceanography Unit, University of Li\u00E8ge, Belgium. Anwesha Ghosh, Centre for Climate and Environmental Studies, Indian Institute of Science Education and Research Kolkata, Moahnpur, Nadia, West Bengal, India. Yaru Li, Plymouth Marine Laboratory, Plymouth, UK. Kaitlyn B. Lowder, The Ocean Foundation, Washington, DC, USA. Shreya Mehta, Geosciences Division, Physical Research Laboratory, Ahmedabad, Gujarat, India. Bryce Van Dam, Institute of Carbon Cycles, Helmholtz-Zentrum Hereon, Geesthacht, Germany. Houda Beghoura, Geophysical Institute, University of Bergen, Bjerknes Centre for Climate Research, Bergen, Norway. Noam Karo, Schulich Faculty of Chemistry, Resnick Sustainability Center for Catalysis, The Nancy & Stephen Grand Technion Energy Program (GTEP), Technion - Israel Institute of Technology, Haifa, Israel. Andrij Z. Horodysky, James J. Howard Laboratory, NOAA Northeast Fisheries Science Center, Highlands, NJ, USA. Sebastian Hennige, School of GeoSciences, University of Edinburgh, UK. Sally M. Salaah, National Institute of Oceanography and Fisheries, Cairo, Egypt. Federica Ragazzola, Genoa Marine Center - Stazione Zoologica Anton Dohrn, Genoa, Italy. Liza Wright-Fairbanks, University Corporation for Atmospheric Research, under contract to NOAA Ocean Acidification Program, Silver Spring, MD, USA.
Alter, K., J. Jacquemont, J. Claudet, M.E. Lattuca, M.E. Barrantes, S. Marras, P.H. Manríquez, C.P. González, D.A. Fernández, M.A. Peck, and others. 2024. Hidden impacts of ocean warming and acidification on biological responses of marine animals revealed through meta-analysis. Nature Communications 15:2885, https://doi.org/10.1038/s41467-024-47064-3.
Artioli, Y., J.C. Blackford, M. Butenschön, J.T. Holt, S.L. Wakelin, H. Thomas, A.V. Borges, and J.I. Allen. 2012. The carbonate system in the North Sea: Sensitivity and model validation. Journal of Marine Systems 102–104:1–13, https://doi.org/10.1016/j.jmarsys.2012.04.006.
Artioli, Y., J.C. Blackford, G. Nondal, R.G.J. Bellerby, S.L. Wakelin, J.T. Holt, M. Butenschön, and J.I. Allen. 2014. Heterogeneity of impacts of high CO2 on the North Western European Shelf. Biogeosciences 11(3):601–612, https://doi.org/10.5194/bg-11-601-2014.
Aumont, O., C. Ethé, A. Tagliabue, L. Bopp, and M. Gehlen. 2015. PISCES-v2: An ocean biogeochemical model for carbon and ecosystem studies. Geoscientific Model Development 8(8):2,465–2,513, https://doi.org/10.5194/gmd-8-2465-2015.
Bach, L.T., D.T. Ho, P.W. Boyd, and M.D. Tyka. 2023. Toward a consensus framework to evaluate air–sea CO2 equilibration for marine CO2 removal. Limnology and Oceanography Letters 8(5):685–691, https://doi.org/10.1002/lol2.10330.
Barton, A., G.G. Waldbusser, R.A. Feely, S.B. Weisberg, J.A. Newton, B. Hales, S. Cudd, B. Eudeline, C.J. Langdon, I. Jefferds, and others. 2015. Impacts of coastal acidification on the Pacific Northwest shellfish industry and adaptation strategies implemented in response. Oceanography 28(2):146–159, https://doi.org/10.5670/oceanog.2015.38.
Bednaršek, N., R.A. Feely, E.L. Howes, B.P.V. Hunt, F. Kessouri, P. León, S. Lischka, A.E. Maas, K. McLaughlin, N.P. Nezlin, and others. 2019. Systematic review and meta-analysis toward synthesis of thresholds of ocean acidification impacts on calcifying pteropods and interactions with warming. Frontiers in Marine Science 6:227, https://doi.org/10.3389/fmars.2019.00227.
Bednaršek, N., P. Calosi, R.A. Feely, R. Ambrose, M. Byrne, K.Y.K. Chan, S. Dupont, J.L. Padilla-Gamiño, J.I. Spicer, F. Kessouri, and others. 2021. Synthesis of thresholds of ocean acidification impacts on echinoderms. Frontiers in Marine Science 8:602601, https://doi.org/10.3389/fmars.2021.602601.
Bednaršek, N., H. Van De Mortel, G. Pelletier, M. García-Reyes, R.A. Feely, and A.G. Dickson. 2025. Assessment framework to predict sensitivity of marine calcifiers to ocean alkalinity enhancement – identification of biological thresholds and importance of precautionary principle. Biogeosciences 22(2):473–498, https://doi.org/10.5194/bg-22-473-2025.
Berger, M., L. Kwiatkowski, D.T. Ho, and L. Bopp. 2023. Ocean dynamics and biological feedbacks limit the potential of macroalgae carbon dioxide removal. Environmental Research Letters 18:024039, https://doi.org/10.1088/1748-9326/acb06e.
Birchenough, S.N.R., H. Reiss, S. Degraer, N. Mieszkowska, Á. Borja, L. Buhl-Mortensen, U. Braeckman, J. Craeymeersch, I. De Mesel, F. Kerckhof, and others. 2015. Climate change and marine benthos: A review of existing research and future directions in the North Atlantic. Wiley Interdisciplinary Reviews: Climate Change 6(2):203–223, https://doi.org/10.1002/wcc.330
Boyd, P.W., H. Claustre, L. Legendre, J.-P. Gattuso, and P.-Y. Le Traon. 2023. Operational monitoring of open-ocean carbon dioxide removal deployments: Detection, attribution, and determination of side effects. Pp. 2–10 in Frontiers in Ocean Observing: Emerging Technologies for Understanding and Managing a Changing Ocean. E.S. Kappel, V. Cullen, M.J. Costello, L. Galgani, C. Gordó-Vilaseca, A. Govindarajan, S. Kouhi, C. Lavin, L. McCartin, J.D. Müller, B. Pirenne, T. Tanhua, Q. Zhao, and S. Zhao, eds, Oceanography 36(Supplement 1), https://doi.org/10.5670/oceanog.2023.s1.2.
Brunner, C., Z. Hausfather, and R. Knutti. 2024. Durability of carbon dioxide removal is critical for Paris climate goals. Communications Earth & Environment 5:645, https://doi.org/10.1038/s43247-024-01808-7.
Busch, D.S., and P. McElhany. 2016. Estimates of the direct effect of seawater pH on the survival rate of species groups in the California Current ecosystem. PLoS ONE 11:e0160669, https://doi.org/10.1371/journal.pone.0160669.
Butenschön, M., T. Lovato, S. Masina, S. Caserini, and M. Grosso. 2021. Alkalinization scenarios in the Mediterranean Sea for efficient removal of atmospheric CO2 and the mitigation of ocean acidification. Frontiers in Climate 3:614537, https://doi.org/10.3389/fclim.2021.614537.
Cai, W.-J., R.A. Feely, J.M. Testa, M. Li, W. Evans, S.R. Alin, Y.-Y. Xu, G. Pelletier, A. Ahmed, D.J. Greeley, and others. 2021. Natural and anthropogenic drivers of acidification in large estuaries. Annual Review of Marine Science 13:23–55, https://doi.org/10.1146/annurev-marine-010419-011004.
Caldiera, K., and M. Wickett. 2003. Anthropogenic carbon and ocean pH. Nature 425(365), https://doi.org/10.1038/425365a.
Carter, B.R., H.C. Bittig, A.J. Fassbender, J.D. Sharp, Y. Takeshita, Y. Xu, M. Álvarez, R. Wanninkhof, R.A. Feely, and L. Barbero. 2021. New and updated global empirical seawater property estimation routines. Limnology and Oceanography Methods 19(12):785–809, https://doi.org/10.1002/lom3.10461.
Clegg, S.L., J.F. Waters, D.R. Turner, and A.G. Dickson. 2023. Chemical speciation models based upon the Pitzer activity coefficient equations, including the propagation of uncertainties: Part III. Seawater from the freezing point to 45°C, including acid-base equilibria. Marine Chemistry 250:104196, https://doi.org/10.1016/j.marchem.2022.104196.
Currie, K., C. Sabine, K. Lowder, A.E.R. Hassoun, M. Melendez, S. Chu, R. Easley, M.I. Garcia-Ibanez, K. Schoo, K. Isensee, and others. 2024. Practical Best Practices for Ocean Acidification Monitoring (1.1), https://doi.org/10.5281/ZENODO.13876198.
Dobson, K.L., J.A. Newton, S. Widdicombe, K.L. Schoo, M.P. Acquafredda, G. Kitch, A. Bantelman, K. Lowder, A. Valauri-Orton, K. Soapi, and others. 2023. Ocean acidification research for sustainability: Co-designing global action on local scales. ICES Journal of Marine Science 80(2):362–366, https://doi.org/10.1093/icesjms/fsac158.
Doney, S.C., V.J. Fabry, R.A. Feely, and J.A. Kleypas. 2009. Ocean acidification: The other CO2 problem. Annual Review of Marine Science 1:169–192, https://doi.org/10.1146/annurev.marine.010908.163834.
Doney, S.C., W.H. Wolfe, D.C. McKee, and J.G. Fuhrman. 2024. The science, engineering, and validation of marine carbon dioxide removal and storage. Annual Review of Marine Science 17:55–81, https://doi.org/10.1146/annurev-marine-040523-014702.
Dong, Y., D.C.E. Bakker, and P. Landschützer. 2024. Accuracy of ocean CO2 uptake estimates at a risk by a reduction in the data collection. Geophysical Research Letters 51:e2024GL108502, https://doi.org/10.1029/2024GL108502.
Dupont, S., C. Edworthy, C. Sánchez-Noguera, M. Metian, J. Friedrich, S. Flickinger, A. Bantelman, C. Galdino, F. Graba, O. Anghelici, and L. Hansson. 2025. The IAEA Ocean Acidification International Coordination Centre Capacity Building Program: Empowering member states to address and minimize the impacts of ocean acidification. Oceanography 38(1):111–113, https://doi.org/10.5670/oceanog.2025.102.
Dutkiewicz, S., J.J. Morris, M.J. Follows, J. Scott, O. Levitan, S.T. Dyhrman, and I. Berman-Frank. 2015. Impact of ocean acidification on the structure of future phytoplankton communities. Nature Climate Change 5:1,002–1,006, https://doi.org/10.1038/nclimate2722.
Falkenberg, L.J., R.G.J. Bellerby, S.D. Connell, L.E. Fleming, B. Maycock, B.D. Russell, F.J. Sullivan, and S. Dupont. 2020. Ocean acidification and human health. International Journal of Environment Research and Public Health 17(12):4563, https://doi.org/10.3390/ijerph17124563.
Fassbender, A.J., S.R. Alin, R.A. Feely, A.J. Sutton, J.A. Newton, and R.H. Byrne. 2017. Estimating total alkalinity in the Washington State coastal zone: Complexities and surprising utility for ocean acidification research. Estuaries and Coasts 40:404–418, https://doi.org/10.1007/s12237-016-0168-z.
Fassbender, A.J., B.R. Carter, J.D. Sharp, Y. Huang, M.C. Arroyo, and H. Frenzel. 2023. Amplified subsurface signals of ocean acidification. Global Biogeochemical Cycles 37:e2023GB007843, https://doi.org/10.1029/2023GB007843.
Feely, R.A., C.L. Sabine, J.M. Hernandez-Ayon, D. Lanson, and B. Hales. 2008. Evidence for upwelling of corrosive “acidified” water onto the continental shelf. Science 320(5882):1,490–1,492, https://doi.org/10.1126/science.1155676.
Feely, R.A., S. Alin, B. Carter, N. Bednaršek, B. Hales, F. Chan, T.M. Hill, B. Gaylord, E. Sanford, R.H. Byrne, and others. 2016. Chemical and biological impacts of ocean acidification along the west coast of North America. Estuarine, Coastal and Shelf Science 183(A):260–270, https://doi.org/10.1016/j.ecss.2016.08.043.
Feely, R.A., B.R. Carter, S.R. Alin, D. Greeley, and N. Bednaršek. 2024. The combined effects of ocean acidification and respiration on habitat suitability for marine calcifiers along the west coast of North America. Journal of Geophysical Research: Oceans 129:e2023JC019892, https://doi.org/10.1029/2023JC019892.
Fennel, K., M.C. Long, C. Algar, B. Carter, D. Keller, A. Laurent, J.P. Mattern, R. Musgrave, A. Oschlies, J. Ostiguy, and others. 2023. Modelling considerations for research on ocean alkalinity enhancement (OAE). State of the Planet 2-oae2023, 9, https://doi.org/10.5194/sp-2-oae2023-9-2023.
Findlay, H.S., Y. Artioli, N. Greenwood, S.E. Hartman, A. Flohr, P. Leon, M. Stiasny, and M. Cronin. 2025. Ocean Acidification Around the UK and Ireland. MCCIP Science Reviews, 31 pp., https://doi.org/10.14465/2025.REU03.OAC.
Form, A.U., and U. Riebesell. 2012. Acclimation to ocean acidification during longterm CO2 exposure in the cold-water coral Lophelia pertusa. Global Change Biology 18(3):843–853, https://doi.org/10.1111/j.1365-2486.2011.02583.x.
Friedlingstein, P., M. O’Sullivan, M.W. Jones, R.M. Andrew, J. Hauck, P. Landschützer, C. Le Quéré, H. Li, I.T. Luijkx, A. Olsen, and others. 2024. Global carbon budget 2024. Earth System Science Data 17(3):965–1,039, https://doi.org/10.5194/essd-2024-519.
González, M.F., and T. Ilyina. 2016. Impacts of artificial ocean alkalinization on the carbon cycle and climate in Earth system simulations. Geophysical Research Letters 43(12):6,493–6,502, https://doi.org/10.1002/2016GL068576.
González, M.F., T. Ilyina, S. Sonntag, and H. Schmidt. 2018. Enhanced rates of regional warming and ocean acidification after termination of large-scale ocean alkalinization. Geophysical Research Letters 45(14):7,120–7,129, https://doi.org/10.1029/2018GL077847.
Grabb, K.C., N. Lord, K.L. Dobson, D.-A. Gordon-Smith, E. Escobar-Briones, M.C. Ford, S. Lander, G. Kitch, M. Meléndez, J.M. Morell, and others. 2025. Building ocean acidification research and policy capacity in the wider Caribbean region: A case study for advancing regional resilience. Frontiers in Marine Science 12:1595911, https://doi.org/10.3389/fmars.2025.1595911.
Gregor, L., and N. Gruber. 2021. OceanSODA-ETHZ: A global gridded data set of the surface ocean carbonate system for seasonal to decadal studies of ocean acidification. Earth System Science Data 13:777–808, https://doi.org/10.5194/essd-13-777-2021.
Gregor, L., J. Shutler, and N. Gruber. 2024. High-resolution variability of the ocean carbon sink. Global Biogeochemical Cycles 38:e2024GB008127, https://doi.org/10.1029/2024GB008127.
Gruber, N., D.C.E. Bakker, T. DeVries, L. Gregor, J. Hauck, P. Landschützer, G.A. McKinley, and J.D. Müller. 2023. Trends and variability in the ocean carbon sink. Nature Reviews Earth & Environment 4:119–134, https://doi.org/10.1038/s43017-022-00381-x.
Hall-Spencer, J.M., and B.P. Harvey. 2019. Ocean acidification impacts on coastal ecosystem services due to habitat degradation. Emerging Topics in Life Sciences 3:197–206, https://doi.org/10.1042/etls20180117.
Heuer, R.M., and M. Grosell. 2014. Physiological impacts of elevated carbon dioxide and ocean acidification on fish. American Journal of Physiology: Regulatory, Integrative, and Comparative Physiology 307(9):R1061–R1084, https://doi.org/10.1152/ajpregu.00064.2014.
Hirsh, H.K., K.J. Nickols, Y. Takeshita, S.B. Traiger, D.A. Mucciarone, S. Monismith, and R.B. Dunbar. 2020. Drivers of biogeochemical variability in a Central California kelp forest: Implications for local amelioration of ocean acidification. Journal of Geophysical Research: Oceans 125:e2020JC016320, https://doi.org/10.1029/2020JC016320.
Hu, N., P.E. Bourdeau, and J. Hollander. 2024. Responses of marine trophic levels to the combined effects of ocean acidification and warming. Nature Communications 15:3400, https://doi.org/10.1038/s41467-024-47563-3.
Hurd, C.L., C.D. Hepburn, K.I. Currie, J.A. Raven, and K.A. Hunter. 2009. Testing the effects of ocean acidification on algal metabolism: Considerations for experimental designs. Journal of Phycology 45:1,236–1,251, https://doi.org/10.1111/j.1529-8817.2009.00768.x.
Hutchins, D.A., M.R. Mulholland, and F. Fu. 2009. Nutrient cycles and marine microbes in a CO2-enriched ocean. Oceanography 22(4):128–145, https://doi.org/10.5670/oceanog.2009.103.
IOC-UNESCO. 2024. State of the Ocean Report. IOC Technical Series, 190, IOC-UNESCO, Paris, 88 pp.
IPCC (Intergovernmental Panel on Climate Change). 2021. Summary for Policymakers. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change. V. Masson-Delmotte, P. Zhai, A. Pirani, S.L. Connors, C. Péan, S. Berger, N. Caud, Y. Chen, L. Goldfarb, M.I. Gomis, M. Huang, K. Leitzell, E. Lonnoy, J.B.R. Matthews, T.K. Maycock, T. Waterfeld, O. Yelekçi, R. Yu, and B. Zhou eds, Cambridge, UK, and New York, NY, USA.
Isaak, A.L., M. Ho, M.S. Dhillon, M.D. Johnson, H. Westphal, and S.S. Doo. 2024. Macroalgal presence decreases coral calcification rates more than ocean acidification. Coral Reefs 43:1,133–1,137, https://doi.org/10.1007/s00338-024-02515-7.
Jiang, J., L. Cao, X. Jin, Z. Yu, H. Zhang, J. Fu, and G. Jiang. 2023. Response of ocean acidification to atmospheric carbon dioxide removal. Journal of Environmental Sciences 140:79–90, https://doi.org/10.1016/j.jes.2023.04.029.
Jiang, L.Q., J.P. Dunne, B. Carter, J. Tjiputra, J. Terhaar, J.D. Sharp, A. Olsen, S. Alin, D.C.E. Bakker, R. Feely, and others. 2022. Global surface ocean acidification indicators from 1750 to 2100 (NCEI Accession 0259391). NOAA National Centers for Environmental Information, Dataset, https://doi.org/10.25921/9ker-bc48.
Karunarathne, S., S. Andrenacci, A. Carranza-Abaid, C. Jayarathna, M. Maelum, R. Skagestad, and H. Aksel Haugen. 2025. Review on CO2 removal from ocean with an emphasis on direct ocean capture (DOC) technologies. Separation and Purification Technology 353:128598, https://doi.org/10.1016/j.seppur.2024.128598.
Keil, K.E., T. Klinger, J.E. Keister, and A.K. McLaskey. 2021. Comparative sensitivities of zooplankton to ocean acidification conditions in experimental and natural settings. Frontiers in Marine Science 8:613778, https://doi.org/10.3389/fmars.2021.613778.
Khangaonkar, T., B.R. Carter, L. Premathilake, S.K. Yun, W. Ni, M.M. Stoll, N.D. Ward, L.G. Hemery, C.T. Sanchez, C.V. Subban, and others. 2024. Mixing and dilution controls on marine CO2 removal using alkalinity enhancement. Environmental Research Letters 19:104039, https://doi.org/10.1088/1748-9326/ad7521.
Kitch, G.D., P.J. Duke, K.C. Grabb, S. Simancas, F.O. Adekunbi, C.I. Addey, L.A. Arbilla, A.C.O. Carvalho, S.N. Chu, R.A. Green, and others. 2025. Early career recommendations for the equitable growth of a marine carbon dioxide removal sector. Perspectives of Earth and Space Scientists 6(1):e2024CN000246, https://doi.org/10.1029/2024CN000246.
Kleypas, J.A., R.A. Feely, V.J. Fabry, C. Langdon, C.L. Sabine, and L.L. Robbins. 2005. Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifiers: A Guide for Future Research. Report of a workshop sponsored by NSF, NOAA, and USGS, held April 18–20, 2005, St. Petersburg, Florida, 88 pp, https://www.pmel.noaa.gov/pubs/PDF/kley2897/kley2897.pdf.
Kroeker, K.J., R.L. Kordas, R. Crim, I.E. Hendriks, L. Ramajo, G.S. Singh, C.M. Duarte, and J.P. Gattuso. 2013. Impacts of ocean acidification on marine organisms: Quantifying sensitivities and interaction with warming. Global Change Biology 19(6):1,884–1,896, https://doi.org/10.1111/gcb.12179.
Krumhardt, K.M., N.S. Lovenduski, M.C. Long, M. Levy, K. Lindsay, J.K. Moore, and C. Nissen. 2019. Coccolithophore growth and calcification in an acidified ocean: Insights from community Earth system model simulations. Journal of Advances in Modeling Earth Systems 11(5):1,418–1,437, https://doi.org/10.1029/2018MS001483.
Land, P.E., H.S. Findlay, J.D. Shutler, I.G.C. Ashton, T. Holding, A. Grouazel, F. Girard-Ardhuin, N. Reul, J.-F. Piolle, B. Chapron, and others. 2019. Optimum satellite remote sensing of the marine carbonate system using empirical algorithms in the global ocean, the Greater Caribbean, the Amazon Plume and the Bay of Bengal. Remote Sensing of Environment 235:111469, https://doi.org/10.1016/j.rse.2019.111469.
Lang, F., J. Gwinn, K. Grabb, A. Valauri-Orton, and G. Spencer. 2024. Guide to Developing Mentoring Programs for the International Ocean Community. The Ocean Foundation, 31 pp., https://oceanfdn.org/wp-content/uploads/2024/01/TOF-Guide-to-Ocean-Mentoring_high-res.pdf.
Lewis, C.N., K.A. Brown, L.A. Edwards, G. Cooper, and H.S. Findlay. 2013. Sensitivity to ocean acidification parallels natural pCO2 gradients experienced by Arctic copepods under winter sea ice. Proceedings of the National Academy of Sciences of the United States of America 110(51):E4960–E4967, https://doi.org/10.1073/pnas.1315162110.
Li, H., S. Zheng, Q.-G. Tan, L. Zhan, T.R. Martz, and J. Ma. 2023. Toward citizen science-based ocean acidification observations using smartphone devices. Analytical Chemistry 95(41):15,409–15,417, https://doi.org/10.1021/acs.analchem.3c03720.
Lowder, K.B., M.S. deVries, R. Hattingh, J.M.D. Day, A.J. Andersson, P.J. Zerofski, and J.R.A. Taylor. 2022. Exoskeletal predator defenses of juvenile California spiny lobsters (Panulirus interruptus) are affected by fluctuating ocean acidification-like conditions. Frontiers in Marine Science 9:909017, https://doi.org/10.3389/fmars.2022.909017.
Mangan, S., R.W. Wilson, H.S. Findlay, and C. Lewis. 2019. Acid–base physiology over tidal periods in the mussel Mytilus edulis: Size and temperature are more influential than seawater pH. Proceedings of the Royal Society B: Biological Sciences 286(1897), https://doi.org/10.1098/rspb.2018.2863.
McGovern, E., J. Schilder, Y. Artioli, S. Birchenough, S. Dupont, H.S. Findlay, I. Skjelvan, M.D. Skogen, M. Álvarez, J.V. Büsher, and others. 2023. Ocean acidification. In OSPAR, 2023: The 2023 Quality Status Report for the North-East Atlantic. OSPAR Commission, London, https://oap.ospar.org/en/ospar-assessments/quality-status-reports/qsr-2023/other-assessments/ocean-acidification/.
Meyer, A.M., and M.J. Spalding. 2021. A Critical Analysis of the Ocean Effects of Carbon Dioxide Removal via Direct Air and Ocean Capture – Is it a Safe and Sustainable Solution? The Ocean Foundation, 18 pp., https://oceanfdn.org/wp-content/uploads/2021/04/Direct-Carbon-Removal-Strategies-TOF-v20Apr21.pdf.
Mongin, M., M.E. Baird, A. Lenton, C. Neill, and J. Akl. 2021. Reversing ocean acidification along the Great Barrier Reef using alkalinity injection. Environmental Research Letters 16:064068, https://doi.org/10.1088/1748-9326/ac002d.
Mos, B., M. Byrne, and S.A. Dworjanyn. 2020. Effects of low and high pH on sea urchin settlement, implications for the use of alkali to counter the impacts of acidification. Aquaculture 528:735618, https://doi.org/10.1016/j.aquaculture.2020.735618.
Müller, J.D., and N. Gruber. 2024. Progression of ocean interior acidification over the industrial era. Science Advances 10:eado3103, https://doi.org/10.1126/sciadv.ado3103.
Narita, D., and K. Rehdanz. 2017. Economic impact of ocean acidification on shellfish production in Europe. Journal of Environmental Planning and Management 60:500–518, https://doi.org/10.1080/09640568.2016.1162705.
NASEM (National Academies of Sciences, Engineering, and Medicine). 2022. A Research Strategy for Ocean-based Carbon Dioxide Removal and Sequestration. National Academies Press, Washington, DC, 322 pp., https://doi.org/10.17226/26278.
Nawaz, S., C. Scott-Buechler, and H. Caggiano. 2024. An independent public engagement body is needed to responsibly scale carbon removal in the US. Environmental Research Letters 19:011002, https://doi.org/10.1088/1748-9326/ad1081.
Newton, J., R. Feely, E. Jewett, P. Williamson, and J. Mathis. 2015. Global Ocean Acidification Observing Network: Requirements and Governance Plan. Global Ocean Acidification Observing Network, 57 pp., https://cdn.ioos.noaa.gov/media/2019/08/GOA-ON_plan_print.pdf.
Newton, J., S. Widdicombe, K. Isensee, S. Dupont, S. Flickinger, K. Grabb, E. Keister, K. Schoo, A. Kenworthy, and A. Valauri-Orton. 2025. Ocean acidification capacity is needed at all levels to develop a multistakeholder ocean acidification action platform. Oceanography 38(1):99–100, https://doi.org/10.5670/oceanog.2025.101.
OA-ICC (Ocean Acidification International Coordination Centre). 2023. Data compilation on the biological response to ocean acidification: 2008–2023 [dataset]. PANGAEA, https://doi.org/10.1594/PANGAEA.962556.
Orr, J.C., J.-M. Epitalon, A.G. Dickson, and J.-P. Gattuso. 2018. Routine uncertainty propagation for the marine carbon dioxide system. Marine Chemistry 207:84–107, https://doi.org/10.1016/j.marchem.2018.10.006.
Oschlies, A., A. Stevenson, L.T. Bach, K. Fennel, R.E.M. Rickaby, T. Satterfield, R. Webb, and J.-P. Gattuso, eds. 2023. Guide to Best Practices in Ocean Alkalinity Enhancement Research. State of the Planet 2-oae2023, https://doi.org/10.5194/sp-2-oae2023.
Palmiéri, J., and A. Yool. 2024. Global-scale evaluation of coastal ocean alkalinity enhancement in a fully coupled Earth system model. Earth’s Future 12:e2023EF004018, https://doi.org/10.1029/2023EF004018.
Pardis, W., K.C. Grabb, M.D. DeGrandpre, R. Spaulding, J. Beck, J.A. Pfeifer, and D.M. Long. 2022. Measuring protons with photons: A hand-held, spectrophotometric pH analyzer for ocean acidification research, community science and education. Sensors 22:7924, https://doi.org/10.3390/s22207924.
Pedersen, F., and P. Hansen. 2003. Effects of high pH on a natural marine planktonic community. Marine Ecology Progress Series 260:19–31, https://doi.org/10.3354/meps260019.
Planchat, A., L. Kwiatkowski, L. Bopp, O. Torres, J.R. Christian, M. Butenschön, T. Lovato, R. Séférian, M.A. Chamberlain, O. Aumont, and others. 2023. The representation of alkalinity and the carbonate pump from CMIP5 to CMIP6 Earth system models and implications for the carbon cycle. Biogeosciences 20(7):1,195–1,257, https://doi.org/10.5194/bg-20-1195-2023.
Renforth, P., and G. Henderson. 2017. Assessing ocean alkalinity for carbon sequestration. Reviews of Geophysics 55:636–674, https://doi.org/10.1002/2016RG000533.
Ricart, A.M., B. Gaylord, T.M. Hill, J.D. Sigwart, P. Shukla, M. Ward, A. Ninokawa, and E. Sanford. 2021. Seagrass-driven changes in carbonate chemistry enhance oyster shell growth. Oecologia 196:565–576, https://doi.org/10.1007/s00442-021-04949-0.
Riebesell, U., V.J. Fabry, L. Hansson, and J.-P. Gattuso. 2011. Guide to Best Practices for Ocean Acidification Research and Data Reporting. Office for Official Publications of the European Communities, 258 pp., https://doi.org/10.2777/58454.
Rose, K.C., E.M. Ferrer, S.R. Carpenter, S.A. Crowe, S.C. Donelan, V.C. Garçon, M. Grégoire, S.F. Jane, P.R. Leavitt, L.A. Levin, and others. 2024. Aquatic deoxygenation as a planetary boundary and key regulator of Earth system stability. Nature Ecology & Evolution 8:1,400–1,406, https://doi.org/10.1038/s41559-024-02448-y.
Schulz, K.G., L.T. Bach, and A.G. Dickson. 2023. Seawater carbonate chemistry considerations for ocean alkalinity enhancement research: theory, measurements, and calculations. State of the Planet, 2-oae2023, 2, https://doi.org/10.5194/sp-2-oae2023-2-2023.
Secretariat of the Convention on Biological Diversity. 2014. An Updated Synthesis of the Impacts of Ocean Acidification on Marine Biodiversity. CBD Technical Series No. 75, Secretariat of the Convention on Biological Diversity, Montreal, 99 pp., https://www.cbd.int/doc/publications/cbd-ts-75-en.pdf.
Smith, S., S. Fuss, H. Buck, F. Schenuit, J. Pongratz, I. Schulte, W.F. Lamb, B. Probst, M. Edwards, G.F. Nemet, and others. 2024. “The State of Carbon Dioxide Removal, 2nd ed.,” https://doi.org/10.17605/OSF.IO/F85QJ.
Suitner, N., G. Faucher, C. Lim, J. Schneider, C.A. Moras, U. Riebesell, and J. Hartmann. 2024. Ocean alkalinity enhancement approaches and the predictability of runaway precipitation processes: Results of an experimental study to determine critical alkalinity ranges for safe and sustainable application scenarios. Biogeosciences 21(20):4,587–4,604, https://doi.org/10.5194/bg-21-4587-2024.
Sundin, J. 2023. The effects of ocean acidification on fishes – History and future outlook. Journal of Fish Biology 103:765–772, https://doi.org/10.1111/jfb.15323.
Tagliabue, A., B.S. Twining, N. Barrier, O. Maury, M. Berger, and L. Bopp. 2023. Ocean iron fertilization may amplify climate change pressures on marine animal biomass for limited climate benefit. Global Change Biology 29:5,250–5,260, https://doi.org/10.1111/gcb.16854.
Thor, P., F. Vermandele, A. Bailey, E. Guscelli, L. Loubet-Sartrou, S. Dupont, and P. Calosi. 2022. Ocean acidification causes fundamental changes in the cellular metabolism of the Arctic copepod Calanus glacialis as detected by metabolomic analysis. Scientific Reports 12:22223, https://doi.org/10.1038/s41598-022-26480-9.
Valauri-Orton, A., K. Lowder, K. Currie, C.L. Sabine, A.G. Dickson, S.N. Chu, A. Acosta, F.E. Asuquo, R. Bermudez, U. Bilounga, and others. 2025. Perspectives from developers and users of the GOA-ON in a Box kit: A model for capacity sharing in ocean sciences. Oceanography 38(1):96–98, https://doi.org/10.5670/oceanog.2025.135.
Van Dam, B.R., and H. Wang. 2019. Decadal-scale acidification trends in adjacent North Carolina estuaries: Competing role of anthropogenic CO2 and riverine alkalinity loads. Frontiers in Marine Science 6:136, https://doi.org/10.3389/fmars.2019.00136.
Vargas, C.A., L.A. Cuevas, B.R. Broitman, V.A. San Martin, N.A. Lagos, J.D. Gaitán-Espitia, and S. Dupont. 2022. Upper environmental pCO2 drives sensitivity to ocean acidification in marine invertebrates. Nature Climate Change 12:200–207, https://doi.org/10.1038/s41558-021-01269-2.
Vivian, C., M. Boettcher, and P. Boyd. 2024. Potential of marine carbon dioxide removal (mCDR) to increase the ocean carbon sink. Pp. 55–58 in State of the Ocean Report 2024. IOC Technical Series 190, UNESCO-IOC, Paris, France, https://doi.org/10.25607/4wbg-d349.
Wahl, M., S. Schneider Covachã, V. Saderne, C. Hiebenthal, J.D. Müller, C. Pansch, and Y. Sawall. 2018. Macroalgae may mitigate ocean acidification effects on mussel calcification by increasing pH and its fluctuations. Limnology and Oceanography 63(1):3–21, https://doi.org/10.1002/lno.10608.
Wang, H., D.J. Pilcher, K.A. Kearney, J.N. Cross, O.M. Shugart, M.D. Eisaman, and B.R. Carter. 2023. Simulated impact of ocean alkalinity enhancement on atmospheric CO2 removal in the Bering Sea. Earth’s Future 11:e2022EF002816, https://doi.org/10.1029/2022EF002816.
Widdicombe, S., K. Isensee, Y. Artioli, J.D. Gaitán-Espitia, C. Hauri, J.A. Newton, M. Wells, and S. Dupont. 2023. Unifying biological field observations to detect and compare ocean acidification impacts across marine species and ecosystems: What to monitor and why. Ocean Science 19(1):101–119, https://doi.org/10.5194/os-19-101-2023.
Wolf-Gladrow, D.A., and C. Klaas. 2024. Total alkalinity change: The perspective of phytoplankton stoichiometry. Limnology and Oceanography 69(8):1,900–1,904, https://doi.org/10.1002/lno.12597.
Wood, H.L., J.I. Spicer, and S. Widdicombe. 2008. Ocean acidification may increase calcification rates, but at a cost. Proceedings of the Royal Society B: Biological Sciences 275:1,767–1,773, https://doi.org/10.1098/rspb.2008.0343.
Yool, A., E.E. Popova, and T.R. Anderson. 2013. MEDUSA-2.0: An intermediate complexity biogeochemical model of the marine carbon cycle for climate change and ocean acidification studies. Geoscientific Model Development 6(5):1,767–1,811, https://doi.org/10.5194/gmd-6-1767-2013.
Young, C.S., and C.J. Gobler. 2018. The ability of macroalgae to mitigate the negative effects of ocean acidification on four species of North Atlantic bivalve. Biogeosciences 15:6,167–6,183, https://doi.org/10.5194/bg-15-6167-2018.
Zhou, M. M.D. Tyka, D.T. Ho, E. Yankovsky, S. Bachman, T. Nichola, A.R. Karspeck, and M.C. Long. 2025. Mapping the global variation in the efficiency of ocean alkalinity enhancement for carbon dioxide removal. Nature Climate Change 15:59–65, https://doi.org/10.1038/s41558-024-02179-9.
