Articles | Volume 21, issue 5
https://doi.org/10.5194/os-21-2179-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-21-2179-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
02 Oct 2025
Research article | Highlight paper |
| 02 Oct 2025
| 02 Oct 2025
The coupled oxygen and carbon dynamics in the subsurface waters of the Gulf and Lower St. Lawrence Estuary and implications for artificial oxygenation
William A. Nesbitt
CORRESPONDING AUTHOR
Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada
Samuel W. Stevens
Hakai Institute, Heriot Bay, British Columbia, Canada
Department of Earth, Ocean and Atmospheric Sciences, The University of British Columbia, Vancouver, British Columbia, Canada
Alfonso O. Mucci
GEOTOP and Department of Earth and Planetary Sciences, McGill University, Montreal, Quebec, Canada
Lennart Gerke
Marine Biogeochemistry Research Division, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
[C]Worthy, LLC, Boulder, CO, USA
Toste Tanhua
Marine Biogeochemistry Research Division, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Gwénaëlle Chaillou
Québec Océan and Institut des sciences de la mer de Rimouski (ISMER), Université du Québec à Rimouski, Rimouski, Québec, Canada
Douglas W. R. Wallace
Department of Oceanography, Dalhousie University, Halifax, Nova Scotia, Canada
Related authors
Lennart Gerke, Toste Tanhua, William A. Nesbitt, Samuel W. Stevens, and Douglas W. R. Wallace
EGUsphere, https://doi.org/10.5194/egusphere-2025-3999, https://doi.org/10.5194/egusphere-2025-3999, 2025
This preprint is open for discussion and under review for Ocean Science (OS).
Short summary
Short summary
Transient tracer data, measured for the first time in 2022 in the Gulf of St. Lawrence, reveal older deep waters in the east than the west, contrary to expected estuarine circulation, indicating increased influence of older, warmer, less oxygenated North Atlantic Central Water over younger, oxygen-rich Labrador Current Water. While consistent with previous reports of increasing NACW contribution, our results contradict claims of a complete shift to NACW by 2021, showing that LCW still persists.
Mathilde Jutras, Alfonso Mucci, Gwenaëlle Chaillou, William A. Nesbitt, and Douglas W. R. Wallace
Biogeosciences, 20, 839–849, https://doi.org/10.5194/bg-20-839-2023, https://doi.org/10.5194/bg-20-839-2023, 2023
Short summary
Short summary
The deep waters of the lower St Lawrence Estuary and gulf have, in the last decades, experienced a strong decline in their oxygen concentration. Below 65 µmol L-1, the waters are said to be hypoxic, with dire consequences for marine life. We show that the extent of the hypoxic zone shows a seven-fold increase in the last 20 years, reaching 9400 km2 in 2021. After a stable period at ~ 65 µmol L⁻¹ from 1984 to 2019, the oxygen level also suddenly decreased to ~ 35 µmol L-1 in 2020.
Lennart Gerke, Toste Tanhua, William A. Nesbitt, Samuel W. Stevens, and Douglas W. R. Wallace
EGUsphere, https://doi.org/10.5194/egusphere-2025-3999, https://doi.org/10.5194/egusphere-2025-3999, 2025
This preprint is open for discussion and under review for Ocean Science (OS).
Short summary
Short summary
Transient tracer data, measured for the first time in 2022 in the Gulf of St. Lawrence, reveal older deep waters in the east than the west, contrary to expected estuarine circulation, indicating increased influence of older, warmer, less oxygenated North Atlantic Central Water over younger, oxygen-rich Labrador Current Water. While consistent with previous reports of increasing NACW contribution, our results contradict claims of a complete shift to NACW by 2021, showing that LCW still persists.
Haichao Guo, Wolfgang Koeve, Andreas Oschlies, Yan-Chun He, Tronje Peer Kemena, Lennart Gerke, and Iris Kriest
Ocean Sci., 21, 1167–1182, https://doi.org/10.5194/os-21-1167-2025, https://doi.org/10.5194/os-21-1167-2025, 2025
Short summary
Short summary
We evaluated the effectiveness of the inverse Gaussian transit time distribution (IG-TTD) with respect to estimating the mean state and temporal changes of seawater age, defined as the duration since water last had contact with the atmosphere, within the tropical thermocline. Results suggest that the IG-TTD underestimates seawater age. Moreover, the IG-TTD constrained by a single tracer gives spurious trends in water age. Incorporating an additional tracer improves IG-TTD's accuracy for estimating temporal change of seawater age.
Li-Qing Jiang, Amanda Fay, Jens Daniel Müller, Lydia Keppler, Dustin Carroll, Siv K. Lauvset, Tim DeVries, Judith Hauck, Christian Rödenbeck, Luke Gregor, Nicolas Metzl, Andrea J. Fassbender, Jean-Pierre Gattuso, Peter Landschützer, Rik Wanninkhof, Christopher Sabine, Simone R. Alin, Mario Hoppema, Are Olsen, Matthew P. Humphreys, 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, Lucas Gloege, Melchor González-Dávila, Nicolas Gruber, Yosuke Iida, Masao Ishii, 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, Alizée Roobaert, 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, Hyelim Yoo, and Jiye Zeng
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2025-255, https://doi.org/10.5194/essd-2025-255, 2025
Preprint under review for ESSD
Short summary
Short summary
This review article provides an overview of 60 existing ocean carbonate chemistry data products, 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.
Anne-Marie Wefing, Annabel Payne, Marcel Scheiwiller, Christof Vockenhuber, Marcus Christl, Toste Tanhua, and Núria Casacuberta
EGUsphere, https://doi.org/10.5194/egusphere-2025-1322, https://doi.org/10.5194/egusphere-2025-1322, 2025
Short summary
Short summary
Here we used the anthropogenic radionuclides I-129 and U-236 as tracers for Atlantic Water circulation in the Arctic Ocean. New data collected in 2021 allowed to assess the distribution of Atlantic Water and mixing with Pacific-origin water in the surface layer in that year. By using historical tracer data from 2011 to 2021, we looked into temporal changes of the circulation and found slightly older waters in the central Arctic Ocean in 2021 compared to 2015.
Aude Flamand, Jean-François Lapierre, and Gwénaëlle Chaillou
EGUsphere, https://doi.org/10.5194/egusphere-2024-2945, https://doi.org/10.5194/egusphere-2024-2945, 2024
Short summary
Short summary
In the context of climate change, increasing rates of coastal erosion and thawing of permafrost increase the fluxes of solutes to the Arctic Ocean. However, the fate of this newly mobilized material is still unclear and may alter ocean chemistry. We have explored the lateral inputs of carbon from coastal permafrost bluffs to the ocean via beaches in Kugmallit Bay. Our findings highlight that beaches may act as a permanent or transient terrestrial carbon sink, limiting its lateral export.
Mian Liu and Toste Tanhua
EGUsphere, https://doi.org/10.5194/egusphere-2024-1362, https://doi.org/10.5194/egusphere-2024-1362, 2024
This preprint is open for discussion and under review for Ocean Science (OS).
Short summary
Short summary
Quantifies Atlantic water mass ages using CFC-12, SF₆, and ³⁹Ar tracers. Reveals ventilation timescales: surface (~100y mean), intermediate (AAIW ~300y), deep (NADW ~600y), bottom (NEABW ~800y). Shows younger ages in western basins due to better ventilation. Provides framework for biogeochemical studies.
Siv K. Lauvset, Nico Lange, Toste Tanhua, Henry C. Bittig, Are Olsen, Alex Kozyr, Marta Álvarez, Kumiko Azetsu-Scott, Peter J. Brown, Brendan R. Carter, Leticia Cotrim da Cunha, Mario Hoppema, Matthew P. Humphreys, Masao Ishii, Emil Jeansson, Akihiko Murata, Jens Daniel Müller, Fiz F. Pérez, Carsten Schirnick, Reiner Steinfeldt, Toru Suzuki, Adam Ulfsbo, Anton Velo, Ryan J. Woosley, and Robert M. Key
Earth Syst. Sci. Data, 16, 2047–2072, https://doi.org/10.5194/essd-16-2047-2024, https://doi.org/10.5194/essd-16-2047-2024, 2024
Short summary
Short summary
GLODAP is a data product for ocean inorganic carbon and related biogeochemical variables measured by the chemical analysis of water bottle samples from scientific cruises. GLODAPv2.2023 is the fifth update of GLODAPv2 from 2016. The data that are included have been subjected to extensive quality controlling, including systematic evaluation of measurement biases. This version contains data from 1108 hydrographic cruises covering the world's oceans from 1972 to 2021.
Nico Lange, Björn Fiedler, Marta Álvarez, Alice Benoit-Cattin, Heather Benway, Pier Luigi Buttigieg, Laurent Coppola, Kim Currie, Susana Flecha, Dana S. Gerlach, Makio Honda, I. Emma Huertas, Siv K. Lauvset, Frank Muller-Karger, Arne Körtzinger, Kevin M. O'Brien, Sólveig R. Ólafsdóttir, Fernando C. Pacheco, Digna Rueda-Roa, Ingunn Skjelvan, Masahide Wakita, Angelicque White, and Toste Tanhua
Earth Syst. Sci. Data, 16, 1901–1931, https://doi.org/10.5194/essd-16-1901-2024, https://doi.org/10.5194/essd-16-1901-2024, 2024
Short summary
Short summary
The Synthesis Product for Ocean Time Series (SPOTS) is a novel achievement expanding and complementing the biogeochemical data landscape by providing consistent and high-quality biogeochemical time-series data from 12 ship-based fixed time-series programs. SPOTS covers multiple unique marine environments and time-series ranges, including data from 1983 to 2021. All in all, it facilitates a variety of applications that benefit from the collective value of biogeochemical time-series observations.
Alizée Dale, Marion Gehlen, Douglas W. R. Wallace, Germain Bénard, Christian Éthé, and Elena Alekseenko
EGUsphere, https://doi.org/10.5194/egusphere-2023-2538, https://doi.org/10.5194/egusphere-2023-2538, 2023
Preprint archived
Short summary
Short summary
Diatom, which is at the base of a productive food chain that supports valuable fisheries, dominates the total primary production of the Labrador Sea (LS). The synthesis of biogenic silica frustules makes them peculiar among phytoplankton but also dependent on dissolved silicate (DSi). Regular oceanographic surveys show declining DSi concentrations since the mid-1990s. With a model-based approach, we show that weakening deep winter convection was the proximate cause of DSi decline in the LS.
Martine Lizotte, Bennet Juhls, Atsushi Matsuoka, Philippe Massicotte, Gaëlle Mével, David Obie James Anikina, Sofia Antonova, Guislain Bécu, Marine Béguin, Simon Bélanger, Thomas Bossé-Demers, Lisa Bröder, Flavienne Bruyant, Gwénaëlle Chaillou, Jérôme Comte, Raoul-Marie Couture, Emmanuel Devred, Gabrièle Deslongchamps, Thibaud Dezutter, Miles Dillon, David Doxaran, Aude Flamand, Frank Fell, Joannie Ferland, Marie-Hélène Forget, Michael Fritz, Thomas J. Gordon, Caroline Guilmette, Andrea Hilborn, Rachel Hussherr, Charlotte Irish, Fabien Joux, Lauren Kipp, Audrey Laberge-Carignan, Hugues Lantuit, Edouard Leymarie, Antonio Mannino, Juliette Maury, Paul Overduin, Laurent Oziel, Colin Stedmon, Crystal Thomas, Lucas Tisserand, Jean-Éric Tremblay, Jorien Vonk, Dustin Whalen, and Marcel Babin
Earth Syst. Sci. Data, 15, 1617–1653, https://doi.org/10.5194/essd-15-1617-2023, https://doi.org/10.5194/essd-15-1617-2023, 2023
Short summary
Short summary
Permafrost thaw in the Mackenzie Delta region results in the release of organic matter into the coastal marine environment. What happens to this carbon-rich organic matter as it transits along the fresh to salty aquatic environments is still underdocumented. Four expeditions were conducted from April to September 2019 in the coastal area of the Beaufort Sea to study the fate of organic matter. This paper describes a rich set of data characterizing the composition and sources of organic matter.
Mathilde Jutras, Alfonso Mucci, Gwenaëlle Chaillou, William A. Nesbitt, and Douglas W. R. Wallace
Biogeosciences, 20, 839–849, https://doi.org/10.5194/bg-20-839-2023, https://doi.org/10.5194/bg-20-839-2023, 2023
Short summary
Short summary
The deep waters of the lower St Lawrence Estuary and gulf have, in the last decades, experienced a strong decline in their oxygen concentration. Below 65 µmol L-1, the waters are said to be hypoxic, with dire consequences for marine life. We show that the extent of the hypoxic zone shows a seven-fold increase in the last 20 years, reaching 9400 km2 in 2021. After a stable period at ~ 65 µmol L⁻¹ from 1984 to 2019, the oxygen level also suddenly decreased to ~ 35 µmol L-1 in 2020.
Siv K. Lauvset, Nico Lange, Toste Tanhua, Henry C. Bittig, Are Olsen, Alex Kozyr, Simone Alin, Marta Álvarez, Kumiko Azetsu-Scott, Leticia Barbero, Susan Becker, Peter J. Brown, Brendan R. Carter, Leticia Cotrim da Cunha, Richard A. Feely, Mario Hoppema, Matthew P. Humphreys, Masao Ishii, Emil Jeansson, Li-Qing Jiang, Steve D. Jones, Claire Lo Monaco, Akihiko Murata, Jens Daniel Müller, Fiz F. Pérez, Benjamin Pfeil, Carsten Schirnick, Reiner Steinfeldt, Toru Suzuki, Bronte Tilbrook, Adam Ulfsbo, Anton Velo, Ryan J. Woosley, and Robert M. Key
Earth Syst. Sci. Data, 14, 5543–5572, https://doi.org/10.5194/essd-14-5543-2022, https://doi.org/10.5194/essd-14-5543-2022, 2022
Short summary
Short summary
GLODAP is a data product for ocean inorganic carbon and related biogeochemical variables measured by the chemical analysis of water bottle samples from scientific cruises. GLODAPv2.2022 is the fourth update of GLODAPv2 from 2016. The data that are included have been subjected to extensive quality controlling, including systematic evaluation of measurement biases. This version contains data from 1085 hydrographic cruises covering the world's oceans from 1972 to 2021.
Pierre Friedlingstein, Michael O'Sullivan, Matthew W. Jones, Robbie M. Andrew, Luke Gregor, Judith Hauck, Corinne Le Quéré, Ingrid T. Luijkx, Are Olsen, Glen P. Peters, Wouter Peters, Julia Pongratz, Clemens Schwingshackl, Stephen Sitch, Josep G. Canadell, Philippe Ciais, Robert B. Jackson, Simone R. Alin, Ramdane Alkama, Almut Arneth, Vivek K. Arora, Nicholas R. Bates, Meike Becker, Nicolas Bellouin, Henry C. Bittig, Laurent Bopp, Frédéric Chevallier, Louise P. Chini, Margot Cronin, Wiley Evans, Stefanie Falk, Richard A. Feely, Thomas Gasser, Marion Gehlen, Thanos Gkritzalis, Lucas Gloege, Giacomo Grassi, Nicolas Gruber, Özgür Gürses, Ian Harris, Matthew Hefner, Richard A. Houghton, George C. Hurtt, Yosuke Iida, Tatiana Ilyina, Atul K. Jain, Annika Jersild, Koji Kadono, Etsushi Kato, Daniel Kennedy, Kees Klein Goldewijk, Jürgen Knauer, Jan Ivar Korsbakken, Peter Landschützer, Nathalie Lefèvre, Keith Lindsay, Junjie Liu, Zhu Liu, Gregg Marland, Nicolas Mayot, Matthew J. McGrath, Nicolas Metzl, Natalie M. Monacci, David R. Munro, Shin-Ichiro Nakaoka, Yosuke Niwa, Kevin O'Brien, Tsuneo Ono, Paul I. Palmer, Naiqing Pan, Denis Pierrot, Katie Pocock, Benjamin Poulter, Laure Resplandy, Eddy Robertson, Christian Rödenbeck, Carmen Rodriguez, Thais M. Rosan, Jörg Schwinger, Roland Séférian, Jamie D. Shutler, Ingunn Skjelvan, Tobias Steinhoff, Qing Sun, Adrienne J. Sutton, Colm Sweeney, Shintaro Takao, Toste Tanhua, Pieter P. Tans, Xiangjun Tian, Hanqin Tian, Bronte Tilbrook, Hiroyuki Tsujino, Francesco Tubiello, Guido R. van der Werf, Anthony P. Walker, Rik Wanninkhof, Chris Whitehead, Anna Willstrand Wranne, Rebecca Wright, Wenping Yuan, Chao Yue, Xu Yue, Sönke Zaehle, Jiye Zeng, and Bo Zheng
Earth Syst. Sci. Data, 14, 4811–4900, https://doi.org/10.5194/essd-14-4811-2022, https://doi.org/10.5194/essd-14-4811-2022, 2022
Short summary
Short summary
The Global Carbon Budget 2022 describes the datasets and methodology used to quantify the anthropogenic emissions of carbon dioxide (CO2) and their partitioning among the atmosphere, the land ecosystems, and the ocean. These living datasets are updated every year to provide the highest transparency and traceability in the reporting of CO2, the key driver of climate change.
Flavienne Bruyant, Rémi Amiraux, Marie-Pier Amyot, Philippe Archambault, Lise Artigue, Lucas Barbedo de Freitas, Guislain Bécu, Simon Bélanger, Pascaline Bourgain, Annick Bricaud, Etienne Brouard, Camille Brunet, Tonya Burgers, Danielle Caleb, Katrine Chalut, Hervé Claustre, Véronique Cornet-Barthaux, Pierre Coupel, Marine Cusa, Fanny Cusset, Laeticia Dadaglio, Marty Davelaar, Gabrièle Deslongchamps, Céline Dimier, Julie Dinasquet, Dany Dumont, Brent Else, Igor Eulaers, Joannie Ferland, Gabrielle Filteau, Marie-Hélène Forget, Jérome Fort, Louis Fortier, Martí Galí, Morgane Gallinari, Svend-Erik Garbus, Nicole Garcia, Catherine Gérikas Ribeiro, Colline Gombault, Priscilla Gourvil, Clémence Goyens, Cindy Grant, Pierre-Luc Grondin, Pascal Guillot, Sandrine Hillion, Rachel Hussherr, Fabien Joux, Hannah Joy-Warren, Gabriel Joyal, David Kieber, Augustin Lafond, José Lagunas, Patrick Lajeunesse, Catherine Lalande, Jade Larivière, Florence Le Gall, Karine Leblanc, Mathieu Leblanc, Justine Legras, Keith Lévesque, Kate-M. Lewis, Edouard Leymarie, Aude Leynaert, Thomas Linkowski, Martine Lizotte, Adriana Lopes dos Santos, Claudie Marec, Dominique Marie, Guillaume Massé, Philippe Massicotte, Atsushi Matsuoka, Lisa A. Miller, Sharif Mirshak, Nathalie Morata, Brivaela Moriceau, Philippe-Israël Morin, Simon Morisset, Anders Mosbech, Alfonso Mucci, Gabrielle Nadaï, Christian Nozais, Ingrid Obernosterer, Thimoté Paire, Christos Panagiotopoulos, Marie Parenteau, Noémie Pelletier, Marc Picheral, Bernard Quéguiner, Patrick Raimbault, Joséphine Ras, Eric Rehm, Llúcia Ribot Lacosta, Jean-François Rontani, Blanche Saint-Béat, Julie Sansoulet, Noé Sardet, Catherine Schmechtig, Antoine Sciandra, Richard Sempéré, Caroline Sévigny, Jordan Toullec, Margot Tragin, Jean-Éric Tremblay, Annie-Pier Trottier, Daniel Vaulot, Anda Vladoiu, Lei Xue, Gustavo Yunda-Guarin, and Marcel Babin
Earth Syst. Sci. Data, 14, 4607–4642, https://doi.org/10.5194/essd-14-4607-2022, https://doi.org/10.5194/essd-14-4607-2022, 2022
Short summary
Short summary
This paper presents a dataset acquired during a research cruise held in Baffin Bay in 2016. We observed that the disappearance of sea ice in the Arctic Ocean increases both the length and spatial extent of the phytoplankton growth season. In the future, this will impact the food webs on which the local populations depend for their food supply and fisheries. This dataset will provide insight into quantifying these impacts and help the decision-making process for policymakers.
Rainer Kiko, Marc Picheral, David Antoine, Marcel Babin, Léo Berline, Tristan Biard, Emmanuel Boss, Peter Brandt, Francois Carlotti, Svenja Christiansen, Laurent Coppola, Leandro de la Cruz, Emilie Diamond-Riquier, Xavier Durrieu de Madron, Amanda Elineau, Gabriel Gorsky, Lionel Guidi, Helena Hauss, Jean-Olivier Irisson, Lee Karp-Boss, Johannes Karstensen, Dong-gyun Kim, Rachel M. Lekanoff, Fabien Lombard, Rubens M. Lopes, Claudie Marec, Andrew M. P. McDonnell, Daniela Niemeyer, Margaux Noyon, Stephanie H. O'Daly, Mark D. Ohman, Jessica L. Pretty, Andreas Rogge, Sarah Searson, Masashi Shibata, Yuji Tanaka, Toste Tanhua, Jan Taucher, Emilia Trudnowska, Jessica S. Turner, Anya Waite, and Lars Stemmann
Earth Syst. Sci. Data, 14, 4315–4337, https://doi.org/10.5194/essd-14-4315-2022, https://doi.org/10.5194/essd-14-4315-2022, 2022
Short summary
Short summary
The term
marine particlescomprises detrital aggregates; fecal pellets; bacterioplankton, phytoplankton and zooplankton; and even fish. Here, we present a global dataset that contains 8805 vertical particle size distribution profiles obtained with Underwater Vision Profiler 5 (UVP5) camera systems. These data are valuable to the scientific community, as they can be used to constrain important biogeochemical processes in the ocean, such as the flux of carbon to the deep sea.
Pierre Friedlingstein, Matthew W. Jones, Michael O'Sullivan, Robbie M. Andrew, Dorothee C. E. Bakker, Judith Hauck, Corinne Le Quéré, Glen P. Peters, Wouter Peters, Julia Pongratz, Stephen Sitch, Josep G. Canadell, Philippe Ciais, Rob B. Jackson, Simone R. Alin, Peter Anthoni, Nicholas R. Bates, Meike Becker, Nicolas Bellouin, Laurent Bopp, Thi Tuyet Trang Chau, Frédéric Chevallier, Louise P. Chini, Margot Cronin, Kim I. Currie, Bertrand Decharme, Laique M. Djeutchouang, Xinyu Dou, Wiley Evans, Richard A. Feely, Liang Feng, Thomas Gasser, Dennis Gilfillan, Thanos Gkritzalis, Giacomo Grassi, Luke Gregor, Nicolas Gruber, Özgür Gürses, Ian Harris, Richard A. Houghton, George C. Hurtt, Yosuke Iida, Tatiana Ilyina, Ingrid T. Luijkx, Atul Jain, Steve D. Jones, Etsushi Kato, Daniel Kennedy, Kees Klein Goldewijk, Jürgen Knauer, Jan Ivar Korsbakken, Arne Körtzinger, Peter Landschützer, Siv K. Lauvset, Nathalie Lefèvre, Sebastian Lienert, Junjie Liu, Gregg Marland, Patrick C. McGuire, Joe R. Melton, David R. Munro, Julia E. M. S. Nabel, Shin-Ichiro Nakaoka, Yosuke Niwa, Tsuneo Ono, Denis Pierrot, Benjamin Poulter, Gregor Rehder, Laure Resplandy, Eddy Robertson, Christian Rödenbeck, Thais M. Rosan, Jörg Schwinger, Clemens Schwingshackl, Roland Séférian, Adrienne J. Sutton, Colm Sweeney, Toste Tanhua, Pieter P. Tans, Hanqin Tian, Bronte Tilbrook, Francesco Tubiello, Guido R. van der Werf, Nicolas Vuichard, Chisato Wada, Rik Wanninkhof, Andrew J. Watson, David Willis, Andrew J. Wiltshire, Wenping Yuan, Chao Yue, Xu Yue, Sönke Zaehle, and Jiye Zeng
Earth Syst. Sci. Data, 14, 1917–2005, https://doi.org/10.5194/essd-14-1917-2022, https://doi.org/10.5194/essd-14-1917-2022, 2022
Short summary
Short summary
The Global Carbon Budget 2021 describes the data sets and methodology used to quantify the emissions of carbon dioxide and their partitioning among the atmosphere, land, and ocean. These living data are updated every year to provide the highest transparency and traceability in the reporting of CO2, the key driver of climate change.
Bjorn Sundby, Pierre Anschutz, Pascal Lecroart, and Alfonso Mucci
Biogeosciences, 19, 1421–1434, https://doi.org/10.5194/bg-19-1421-2022, https://doi.org/10.5194/bg-19-1421-2022, 2022
Short summary
Short summary
A glacial–interglacial methane-fuelled redistribution of reactive phosphorus between the oceanic and sedimentary phosphorus reservoirs can occur in the ocean when falling sea level lowers the pressure on the seafloor, destabilizes methane hydrates, and triggers the dissolution of P-bearing iron oxides. The mass of phosphate potentially mobilizable from the sediment is similar to the size of the current oceanic reservoir. Hence, this process may play a major role in the marine phosphorus cycle.
Jannes Koelling, Dariia Atamanchuk, Johannes Karstensen, Patricia Handmann, and Douglas W. R. Wallace
Biogeosciences, 19, 437–454, https://doi.org/10.5194/bg-19-437-2022, https://doi.org/10.5194/bg-19-437-2022, 2022
Short summary
Short summary
In this study, we investigate oxygen variability in the deep western boundary current in the Labrador Sea from multiyear moored records. We estimate that about half of the oxygen taken up in the interior Labrador Sea by air–sea gas exchange during deep water formation is exported southward the same year. Our results underline the complexity of the oxygen uptake and export in the Labrador Sea and highlight the important role this region plays in supplying oxygen to the deep ocean.
Krysten Rutherford, Katja Fennel, Dariia Atamanchuk, Douglas Wallace, and Helmuth Thomas
Biogeosciences, 18, 6271–6286, https://doi.org/10.5194/bg-18-6271-2021, https://doi.org/10.5194/bg-18-6271-2021, 2021
Short summary
Short summary
Using a regional model of the northwestern North Atlantic shelves in combination with a surface water time series and repeat transect observations, we investigate surface CO2 variability on the Scotian Shelf. The study highlights a strong seasonal cycle in shelf-wide pCO2 and spatial variability throughout the summer months driven by physical events. The simulated net flux of CO2 on the Scotian Shelf is out of the ocean, deviating from the global air–sea CO2 flux trend in continental shelves.
Siv K. Lauvset, Nico Lange, Toste Tanhua, Henry C. Bittig, Are Olsen, Alex Kozyr, Marta Álvarez, Susan Becker, Peter J. Brown, Brendan R. Carter, Leticia Cotrim da Cunha, Richard A. Feely, Steven van Heuven, Mario Hoppema, Masao Ishii, Emil Jeansson, Sara Jutterström, Steve D. Jones, Maren K. Karlsen, Claire Lo Monaco, Patrick Michaelis, Akihiko Murata, Fiz F. Pérez, Benjamin Pfeil, Carsten Schirnick, Reiner Steinfeldt, Toru Suzuki, Bronte Tilbrook, Anton Velo, Rik Wanninkhof, Ryan J. Woosley, and Robert M. Key
Earth Syst. Sci. Data, 13, 5565–5589, https://doi.org/10.5194/essd-13-5565-2021, https://doi.org/10.5194/essd-13-5565-2021, 2021
Short summary
Short summary
GLODAP is a data product for ocean inorganic carbon and related biogeochemical variables measured by the chemical analysis of water bottle samples from scientific cruises. GLODAPv2.2021 is the third update of GLODAPv2 from 2016. The data that are included have been subjected to extensive quality control, including systematic evaluation of measurement biases. This version contains data from 989 hydrographic cruises covering the world's oceans from 1972 to 2020.
Philippe Massicotte, Rainer M. W. Amon, David Antoine, Philippe Archambault, Sergio Balzano, Simon Bélanger, Ronald Benner, Dominique Boeuf, Annick Bricaud, Flavienne Bruyant, Gwenaëlle Chaillou, Malik Chami, Bruno Charrière, Jing Chen, Hervé Claustre, Pierre Coupel, Nicole Delsaut, David Doxaran, Jens Ehn, Cédric Fichot, Marie-Hélène Forget, Pingqing Fu, Jonathan Gagnon, Nicole Garcia, Beat Gasser, Jean-François Ghiglione, Gaby Gorsky, Michel Gosselin, Priscillia Gourvil, Yves Gratton, Pascal Guillot, Hermann J. Heipieper, Serge Heussner, Stanford B. Hooker, Yannick Huot, Christian Jeanthon, Wade Jeffrey, Fabien Joux, Kimitaka Kawamura, Bruno Lansard, Edouard Leymarie, Heike Link, Connie Lovejoy, Claudie Marec, Dominique Marie, Johannie Martin, Jacobo Martín, Guillaume Massé, Atsushi Matsuoka, Vanessa McKague, Alexandre Mignot, William L. Miller, Juan-Carlos Miquel, Alfonso Mucci, Kaori Ono, Eva Ortega-Retuerta, Christos Panagiotopoulos, Tim Papakyriakou, Marc Picheral, Louis Prieur, Patrick Raimbault, Joséphine Ras, Rick A. Reynolds, André Rochon, Jean-François Rontani, Catherine Schmechtig, Sabine Schmidt, Richard Sempéré, Yuan Shen, Guisheng Song, Dariusz Stramski, Eri Tachibana, Alexandre Thirouard, Imma Tolosa, Jean-Éric Tremblay, Mickael Vaïtilingom, Daniel Vaulot, Frédéric Vaultier, John K. Volkman, Huixiang Xie, Guangming Zheng, and Marcel Babin
Earth Syst. Sci. Data, 13, 1561–1592, https://doi.org/10.5194/essd-13-1561-2021, https://doi.org/10.5194/essd-13-1561-2021, 2021
Short summary
Short summary
The MALINA oceanographic expedition was conducted in the Mackenzie River and the Beaufort Sea systems. The sampling was performed across seven shelf–basin transects to capture the meridional gradient between the estuary and the open ocean. The main goal of this research program was to better understand how processes such as primary production are influencing the fate of organic matter originating from the surrounding terrestrial landscape during its transition toward the Arctic Ocean.
Gerd Krahmann, Damian L. Arévalo-Martínez, Andrew W. Dale, Marcus Dengler, Anja Engel, Nicolaas Glock, Patricia Grasse, Johannes Hahn, Helena Hauss, Mark Hopwood, Rainer Kiko, Alexandra Loginova, Carolin R. Löscher, Marie Maßmig, Alexandra-Sophie Roy, Renato Salvatteci, Stefan Sommer, Toste Tanhua, and Hela Mehrtens
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2020-308, https://doi.org/10.5194/essd-2020-308, 2021
Preprint withdrawn
Short summary
Short summary
The project "Climate-Biogeochemistry Interactions in the Tropical Ocean" (SFB 754) was a multidisciplinary research project active from 2008 to 2019 aimed at a better understanding of the coupling between the tropical climate and ocean circulation and the ocean's oxygen and nutrient balance. On 34 research cruises, mainly in the Southeast Tropical Pacific and the Northeast Tropical Atlantic, 1071 physical, chemical and biological data sets were collected.
Pingyang Li and Toste Tanhua
Ocean Sci., 17, 509–525, https://doi.org/10.5194/os-17-509-2021, https://doi.org/10.5194/os-17-509-2021, 2021
Short summary
Short summary
Observations of transient tracer distribution provide essential information on ocean ventilation. The use of several commonly used transient traces is limited as their atmospheric mole fractions do not monotonically change. Here we explore new potential oceanic transient tracers with an analytical system that simultaneously measures a large range of compounds. Combined with the known atmospheric history and seawater solubility, we discuss the utility of selected HCFCs, HFCs, and PFCs as tracers.
Mian Liu and Toste Tanhua
Ocean Sci., 17, 463–486, https://doi.org/10.5194/os-17-463-2021, https://doi.org/10.5194/os-17-463-2021, 2021
Short summary
Short summary
We have characterized the major water masses in the Atlantic Ocean based on the properties found in their formation areas using six properties taken from the GLODAPv2 data product, including both conservative (conservative temperature and absolute salinity) and non-conservative (oxygen, silicate, phosphate and nitrate) properties. The distributions of the water masses are estimated by using the optimum multi-parameter (OMP) model, and we have mapped the distributions of the water masses.
Nicolai von Oppeln-Bronikowski, Brad de Young, Dariia Atamanchuk, and Douglas Wallace
Ocean Sci., 17, 1–16, https://doi.org/10.5194/os-17-1-2021, https://doi.org/10.5194/os-17-1-2021, 2021
Short summary
Short summary
This paper describes challenges around the direct measurement of CO2 in the ocean using ocean gliders. We discuss our method of using multiple sensor platforms as test beds to carry out observing experiments and highlight the implications of our study for future glider missions. We also show high-resolution measurements and discuss challenges and lessons learned in the context of future ocean gas measurements.
Are Olsen, Nico Lange, Robert M. Key, Toste Tanhua, Henry C. Bittig, Alex Kozyr, Marta Álvarez, Kumiko Azetsu-Scott, Susan Becker, Peter J. Brown, Brendan R. Carter, Leticia Cotrim da Cunha, Richard A. Feely, Steven van Heuven, Mario Hoppema, Masao Ishii, Emil Jeansson, Sara Jutterström, Camilla S. Landa, Siv K. Lauvset, Patrick Michaelis, Akihiko Murata, Fiz F. Pérez, Benjamin Pfeil, Carsten Schirnick, Reiner Steinfeldt, Toru Suzuki, Bronte Tilbrook, Anton Velo, Rik Wanninkhof, and Ryan J. Woosley
Earth Syst. Sci. Data, 12, 3653–3678, https://doi.org/10.5194/essd-12-3653-2020, https://doi.org/10.5194/essd-12-3653-2020, 2020
Short summary
Short summary
GLODAP is a data product for ocean inorganic carbon and related biogeochemical variables measured by chemical analysis of water bottle samples at scientific cruises. GLODAPv2.2020 is the second update of GLODAPv2 from 2016. The data that are included have been subjected to extensive quality control, including systematic evaluation of measurement biases. This version contains data from 946 hydrographic cruises covering the world's oceans from 1972 to 2019.
Pierre Friedlingstein, Michael O'Sullivan, Matthew W. Jones, Robbie M. Andrew, Judith Hauck, Are Olsen, Glen P. Peters, Wouter Peters, Julia Pongratz, Stephen Sitch, Corinne Le Quéré, Josep G. Canadell, Philippe Ciais, Robert B. Jackson, Simone Alin, Luiz E. O. C. Aragão, Almut Arneth, Vivek Arora, Nicholas R. Bates, Meike Becker, Alice Benoit-Cattin, Henry C. Bittig, Laurent Bopp, Selma Bultan, Naveen Chandra, Frédéric Chevallier, Louise P. Chini, Wiley Evans, Liesbeth Florentie, Piers M. Forster, Thomas Gasser, Marion Gehlen, Dennis Gilfillan, Thanos Gkritzalis, Luke Gregor, Nicolas Gruber, Ian Harris, Kerstin Hartung, Vanessa Haverd, Richard A. Houghton, Tatiana Ilyina, Atul K. Jain, Emilie Joetzjer, Koji Kadono, Etsushi Kato, Vassilis Kitidis, Jan Ivar Korsbakken, Peter Landschützer, Nathalie Lefèvre, Andrew Lenton, Sebastian Lienert, Zhu Liu, Danica Lombardozzi, Gregg Marland, Nicolas Metzl, David R. Munro, Julia E. M. S. Nabel, Shin-Ichiro Nakaoka, Yosuke Niwa, Kevin O'Brien, Tsuneo Ono, Paul I. Palmer, Denis Pierrot, Benjamin Poulter, Laure Resplandy, Eddy Robertson, Christian Rödenbeck, Jörg Schwinger, Roland Séférian, Ingunn Skjelvan, Adam J. P. Smith, Adrienne J. Sutton, Toste Tanhua, Pieter P. Tans, Hanqin Tian, Bronte Tilbrook, Guido van der Werf, Nicolas Vuichard, Anthony P. Walker, Rik Wanninkhof, Andrew J. Watson, David Willis, Andrew J. Wiltshire, Wenping Yuan, Xu Yue, and Sönke Zaehle
Earth Syst. Sci. Data, 12, 3269–3340, https://doi.org/10.5194/essd-12-3269-2020, https://doi.org/10.5194/essd-12-3269-2020, 2020
Short summary
Short summary
The Global Carbon Budget 2020 describes the data sets and methodology used to quantify the emissions of carbon dioxide and their partitioning among the atmosphere, land, and ocean. These living data are updated every year to provide the highest transparency and traceability in the reporting of CO2, the key driver of climate change.
Dagmar Hainbucher, Marta Álvarez, Blanca Astray Uceda, Giancarlo Bachi, Vanessa Cardin, Paolo Celentano, Spyros Chaikalis, Maria del Mar Chaves Montero, Giuseppe Civitarese, Noelia M. Fajar, Francois Fripiat, Lennart Gerke, Alexandra Gogou, Elisa F. Guallart, Birte Gülk, Abed El Rahman Hassoun, Nico Lange, Andrea Rochner, Chiara Santinelli, Tobias Steinhoff, Toste Tanhua, Lidia Urbini, Dimitrios Velaoras, Fabian Wolf, and Andreas Welsch
Earth Syst. Sci. Data, 12, 2747–2763, https://doi.org/10.5194/essd-12-2747-2020, https://doi.org/10.5194/essd-12-2747-2020, 2020
Short summary
Short summary
We report on data from an oceanographic cruise in the Mediterranean Sea (MSM72, March 2018). The main objective of the cruise was to contribute to the understanding of long-term changes and trends in physical and biogeochemical parameters, such as the anthropogenic carbon uptake, and further assess the hydrographical situation after the Eastern and Western Mediterranean Transients. Multidisciplinary measurements were conducted on a predominantly
zonal section throughout the Mediterranean Sea.
Cited articles
Anderson, L. A. and Sarmiento, J. L.: Redfield ratios of remineralization determined by nutrient data analysis, Global Biogeochemical Cycles, 8, 65–80, https://doi.org/10.1029/93GB03318, 1994.
Audet, T., de Vernal, A., Mucci, A., Seidenkrantz, M.-S., Hillaire-Marcel, C., Carnero-Bravo, V., and Gélinas, Y.: Benthic Foraminiferal Assemblages from the Laurentian Channel in the Lower Estuary and Gulf of ST. Lawrence, Eastern Canada: Tracers of Bottom-Water Hypoxia, Journal of Foraminiferal Research, 53, 57–77, https://doi.org/10.2113/gsjfr.53.1.57, 2023.
Benoit, P., Gratton, Y., and Mucci, A.: Modeling of dissolved oxygen levels in the bottom waters of the Lower St. Lawrence Estuary: Coupling of benthic and pelagic processes, Marine Chemistry, 102, 13–32, https://doi.org/10.1016/j.marchem.2005.09.015, 2006.
Blais, M., Galbraith, P. S., Plourde, S., and Lehoux, C.: Chemical and Biological Oceanographic Conditions in the Estuary and Gulf of St. Lawrence during 2022, Fisheries and Oceans Canada, Québec Region, Maurice Lamontagne Institute, Mont-Joli, QC, https://publications.gc.ca/site/eng/9.924924/publication.html, 2023.
Bluteau, C. E., Galbraith, P. S., Bourgault, D., Villeneuve, V., and Tremblay, J.-É.: Winter observations alter the seasonal perspectives of the nutrient transport pathways into the lower St. Lawrence Estuary, Ocean Sci., 17, 1509–1525, https://doi.org/10.5194/os-17-1509-2021, 2021.
Bourgault, D., Cyr, F., Galbraith, P. S., and Pelletier, E.: Relative importance of pelagic and sediment respiration in causing hypoxia in a deep estuary, Journal of Geophysical Research: Oceans, 117, https://doi.org/10.1029/2012JC007902, 2012.
Breitburg, D. L.: Episodic Hypoxia in Chesapeake Bay: Interacting Effects of Recruitment, Behavior, and Physical Disturbance, Ecological Monographs, 62, 525–546, https://doi.org/10.2307/2937315, 1992.
Breitburg, D. L., Levin, L. A., Oschlies, A., Grégoire, M., Chavez, F. P., Conley, D. J., Garçon, V., Gilbert, D., Gutiérrez, D., Isensee, K., Jacinto, G. S., Limburg, K. E., Montes, I., Naqvi, S. W. A., Pitcher, G. C., Rabalais, N. N., Roman, M. R., Rose, K. A., Seibel, B. A., Telszewski, M., Yasuhara, M., and Zhang, J.: Declining oxygen in the global ocean and coastal waters, Science, 359, eaam7240, https://doi.org/10.1126/science.aam7240, 2018.
Bugden, G. L.: Changes in the temperature-salinity characteristics of the deeper waters of the Gulf of St. Lawrence over the past few decades, Can. J. Fish. Aquat. Sci., 113, 139–147, 1991.
Capet, A., Beckers, J.-M., and Grégoire, M.: Drivers, mechanisms and long-term variability of seasonal hypoxia on the Black Sea northwestern shelf – is there any recovery after eutrophication?, Biogeosciences, 10, 3943–3962, https://doi.org/10.5194/bg-10-3943-2013, 2013.
Cheng, L., Normandeau, C., Bowden, R., Doucett, R., Gallagher, B., Gillikin, D. P., Kumamoto, Y., McKay, J. L., Middlestead, P., Ninnemann, U., Nothaft, D., Dubinina, E. O., Quay, P., Reverdin, G., Shirai, K., Mørkved, P. T., Theiling, B. P., van Geldern, R., and Wallace, D. W. R.: An international intercomparison of stable carbon isotope composition measurements of dissolved inorganic carbon in seawater, Limnology and Oceanography: Methods, 17, 200–209, https://doi.org/10.1002/lom3.10300, 2019.
Conley, D. J., Björck, S., Bonsdorff, E., Carstensen, J., Destouni, G., Gustafsson, B. G., Hietanen, S., Kortekaas, M., Kuosa, H., Markus Meier, H. E., Müller-Karulis, B., Nordberg, K., Norkko, A., Nürnberg, G., Pitkänen, H., Rabalais, N. N., Rosenberg, R., Savchuk, O. P., Slomp, C. P., Voss, M., Wulff, F., and Zillén, L.: Hypoxia-Related Processes in the Baltic Sea, Environ. Sci. Technol., 43, 3412–3420, https://doi.org/10.1021/es802762a, 2009.
Conley, D. J., Carstensen, J., Aigars, J., Axe, P., Bonsdorff, E., Eremina, T., Haahti, B.-M., Humborg, C., Jonsson, P., Kotta, J., Lännegren, C., Larsson, U., Maximov, A., Medina, M. R., Lysiak-Pastuszak, E., Remeikaitë-Nikienë, N., Walve, J., Wilhelms, S., and Zillén, L.: Hypoxia Is Increasing in the Coastal Zone of the Baltic Sea, Environ. Sci. Technol., 45, 6777–6783, https://doi.org/10.1021/es201212r, 2011.
Cyr, F., Bourgault, D., and Galbraith, P. S.: Interior versus boundary mixing of a cold intermediate layer, Journal of Geophysical Research: Oceans, 116, https://doi.org/10.1029/2011JC007359, 2011.
Cyr, F., Bourgault, D., and Galbraith, P. S.: Behavior and mixing of a cold intermediate layer near a sloping boundary, Ocean Dynamics, 65, 357–374, https://doi.org/10.1007/s10236-014-0799-1, 2015.
Diaz, R. J. and Rosenberg, R.: Spreading Dead Zones and Consequences for Marine Ecosystems, Science, 321, 926–929, https://doi.org/10.1126/science.1156401, 2008.
Dickson, A. G., Sabine, C. L., and Christian, J. R.: Guide to Best Practices for Ocean CO2 Measurements, North Pacific Marine Science Organization, 2007.
Fuentes-Yaco, C., Vézina, A. F., Larouche, P., Vigneau, C., Gosselin, M., and Levasseur, M.: Phytoplankton pigment in the Gulf of St. Lawrence, Canada, as determined by the Coastal Zone Color Scanner – Part I: spatio-temporal variability, Continental Shelf Research, 17, 1421–1439, https://doi.org/10.1016/S0278-4343(97)00021-6, 1997.
Galbraith, P. S.: Winter water masses in the Gulf of St. Lawrence, Journal of Geophysical Research: Oceans, 111, https://doi.org/10.1029/2005JC003159, 2006.
Galbraith, P. S., Chassé, J., Shaw, J.-L., Dumas, J., and Bourassa, M.-N.: Physical oceanographic conditions in the Gulf of St. Lawrence during 2023, Fisheries and Oceans Canada, Québec Region, Maurice Lamontagne Institute, Mont-Joli, QC, 2024.
Genovesi, L., de Vernal, A., Thibodeau, B., Hillaire-Marcel, C., Mucci, A., and Gilbert, D.: Recent changes in bottom water oxygenation and temperature in the Gulf of St. Lawrence: Micropaleontological and geochemical evidence, Limnology and Oceanography, 56, 1319–1329, https://doi.org/10.4319/lo.2011.56.4.1319, 2011.
Gilbert, D.: Propagation of Temperature Signals from the Northwest Atlantic Continental Shelf Edge into the Laurentian Channel, in: ICES Council Meeting, N:07, 2004.
Gilbert, D., Sundby, B., Gobeil, C., Mucci, A., and Tremblay, G.-H.: A seventy-two-year record of diminishing deep-water oxygen in the St. Lawrence estuary: The northwest Atlantic connection, Limnol. Oceanogr., 50, 1654–1666, https://doi.org/10.4319/lo.2005.50.5.1654, 2005.
Goranov, A. I., Carter, S. J., Pearson, A., and Hatcher, P. G.: Oxidation Camouflages Terrestrial Organic Matter to Appear Marine-like, Environ. Sci. Technol., 59, 5607–5620, https://doi.org/10.1021/acs.est.4c12913, 2025.
Grasshoff, K., Kremling, K., and Ehrhardt, M.: Methods of Seawater Analysis, 3rd edn., John Wiley & Sons, Weinheim, Germany, 635 pp., https://doi.org/10.1002/9783527613984, 2009.
Hagy, J. D., Boynton, W. R., Keefe, C. W., and Wood, K. V.: Hypoxia in Chesapeake Bay, 1950–2001: Long-term change in relation to nutrient loading and river flow, Estuaries, 27, 634–658, https://doi.org/10.1007/BF02907650, 2004.
Hedges, J. I., Baldock, J. A., Gélinas, Y., Lee, C., Peterson, M. L., and Wakeham, S. G.: The biochemical and elemental compositions of marine plankton: A NMR perspective, Marine Chemistry, 78, 47–63, https://doi.org/10.1016/S0304-4203(02)00009-9, 2002.
Helm, K. P., Bindoff, N. L., and Church, J. A.: Observed decreases in oxygen content of the global ocean, Geophysical Research Letters, 38, https://doi.org/10.1029/2011GL049513, 2011.
Ingram, R. G.: Vertical mixing at the head of the Laurentian Channel, Estuarine, Coastal and Shelf Science, 16, 333–338, https://doi.org/10.1016/0272-7714(83)90150-6, 1983.
IPCC (Intergovernmental Panel on Climate Change): Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Masson-Delmotte, V., Zhai, P., Pirani, A., Connors, S. L., Péan, C., Berger, S., Caud, N., Chen, Y., Goldfarb, L., Gomis, M. I., Huang, M., Leitzell, K., Lonnoy, E., Matthews, J. B. R., Maycock, T. K., Waterfield, T., Yelekçi, Ö., Yu, R., and Zhou, B., Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA, https://doi.org/10.1017/9781009157896, 2021.
Jutras, M., Dufour, C. O., Mucci, A., Cyr, F., and Gilbert, D.: Temporal Changes in the Causes of the Observed Oxygen Decline in the St. Lawrence Estuary, Journal of Geophysical Research: Oceans, 125, e2020JC016577, https://doi.org/10.1029/2020JC016577, 2020.
Jutras, M., Dufour, C. O., Mucci, A., and Talbot, L. C.: Large-scale control of the retroflection of the Labrador Current, Nat. Commun., 14, 2623, https://doi.org/10.1038/s41467-023-38321-y, 2023a.
Jutras, M., Mucci, A., Chaillou, G., Nesbitt, W. A., and Wallace, D. W. R.: Temporal and spatial evolution of bottom-water hypoxia in the St Lawrence estuarine system, Biogeosciences, 20, 839–849, https://doi.org/10.5194/bg-20-839-2023, 2023b.
Keeling, C. D.: The concentration and isotopic abundances of carbon dioxide in rural and marine air, Geochimica et Cosmochimica Acta, 24, 277–298, https://doi.org/10.1016/0016-7037(61)90023-0, 1961.
Körtzinger, A., Hedges, J. I., and Quay, P. D.: Redfield ratios revisited: Removing the biasing effect of anthropogenic CO2, Limnology and Oceanography, 46, 964–970, https://doi.org/10.4319/lo.2001.46.4.0964, 2001.
Laliberté, J. and Larouche, P.: Chlorophyll-a concentration climatology, phenology, and trends in the optically complex waters of the St. Lawrence Estuary and Gulf, Journal of Marine Systems, 238, 103830, https://doi.org/10.1016/j.jmarsys.2022.103830, 2023.
Lefort, S., Mucci, A., and Sundby, B.: Sediment Response to 25 Years of Persistent Hypoxia, Aquat Geochem, 18, 461–474, https://doi.org/10.1007/s10498-012-9173-4, 2012.
Lehmann, M. F., Barnett, B., Gélinas, Y., Gilbert, D., Maranger, R. J., Mucci, A., Sundby, B., and Thibodeau, B.: Aerobic respiration and hypoxia in the Lower St. Lawrence Estuary: Stable isotope ratios of dissolved oxygen constrain oxygen sink partitioning, Limnology and Oceanography, 54, 2157–2169, https://doi.org/10.4319/lo.2009.54.6.2157, 2009.
Levasseur, M., Keller, M. D., Bonneau, E., D'Amours, D., and Bellows, W. K.: Oceanographic Basis of a DMS-Related Atlantic Cod (Gadus morhua) Fishery Problem: Blackberry Feed, Can. J. Fish. Aquat. Sci., 51, 881–889, https://doi.org/10.1139/f94-087, 1994.
Levasseur, M., Sharma, S., Cantin, G., Michaud, S., Gosselin, M., and Barrie, L.: Biogenic sulfur emissions from the Gulf of Saint Lawrence and assessment of its impact on the Canadian east coast, Journal of Geophysical Research: Atmospheres, 102, 28025–28039, https://doi.org/10.1029/97JD01901, 1997.
Lévesque, D., Lebeuf, M., Maltais, D., Anderson, C., and Starr, M.: Transport inventories and exchanges of organic matter throughout the St. Lawrence Estuary continuum (Canada), Front. Mar. Sci., 9, 1055384, https://doi.org/10.3389/fmars.2022.1055384, 2023.
Lucotte, M., Hillaire-Marcel, C., and Louchouarn, P.: First-order organic carbon budget in the St Lawrence Lower estuary from 13C data, Estuarine, Coastal and Shelf Science, 32, 297–312, https://doi.org/10.1016/0272-7714(91)90022-4, 1991.
Mertz, G. and Gratton, Y.: The generation of transverse flows by internal friction in the St. Lawrence Estuary, Continental Shelf Research, 15, 789–801, https://doi.org/10.1016/0278-4343(94)00043-M, 1995.
Moreno, A. R., Garcia, C. A., Larkin, A. A., Lee, J. A., Wang, W.-L., Moore, J. K., Primeau, F. W., and Martiny, A. C.: Latitudinal gradient in the respiration quotient and the implications for ocean oxygen availability, Proceedings of the National Academy of Sciences, 117, 22866–22872, https://doi.org/10.1073/pnas.2004986117, 2020.
Moreno, A. R., Larkin, A. A., Lee, J. A., Gerace, S. D., Tarran, G. A., and Martiny, A. C.: Regulation of the Respiration Quotient Across Ocean Basins, AGU Advances, 3, e2022AV000679, https://doi.org/10.1029/2022AV000679, 2022.
Mucci, A., Starr, M., Gilbert, D., and Sundby, B.: Acidification of Lower St. Lawrence Estuary Bottom Waters, Atmosphere-Ocean, 49, 206–218, https://doi.org/10.1080/07055900.2011.599265, 2011.
Murphy, R. R., Kemp, W. M., and Ball, W. P.: Long-Term Trends in Chesapeake Bay Seasonal Hypoxia, Stratification, and Nutrient Loading, Estuaries and Coasts, 34, 1293–1309, https://doi.org/10.1007/s12237-011-9413-7, 2011.
Murray, J. W., Jannasch, H. W., Honjo, S., Anderson, R. F., Reeburgh, W. S., Top, Z., Friederich, G. E., Codispoti, L. A., and Izdar, E.: Unexpected changes in the oxic/anoxic interface in the Black Sea, Nature, 338, 411–413, https://doi.org/10.1038/338411a0, 1989.
Murray, J. W., Top, Z., and Özsoy, E.: Hydrographic properties and ventilation of the Black Sea, Deep Sea Research Part A. Oceanographic Research Papers, 38, S663–S689, https://doi.org/10.1016/S0198-0149(10)80003-2, 1991.
Nesbitt, W. A. and Mucci, A.: Direct evidence of sediment carbonate dissolution in response to bottom-water acidification in the Gulf of St. Lawrence, Canada, Can. J. Earth Sci., 58, 84–92, https://doi.org/10.1139/cjes-2020-0020, 2021.
Nesbitt, W. A., Mucci, A. O., Tanhua, T., Gelinas, Y., Tremblay, J.-E., Chaillou, G., Pascal, L., Fradette, C., Gerke, L., Stevens, S. W., Jutras, M., Blais, M., Lizotte, M., Starr, M., and Wallace, D. W. R.: St. Lawrence Estuary and Gulf Data Analysis Product, St. Lawrence Global Observatory, Canadian Integrated Ocean Observing System [data set], https://doi.org/10.26071/d6f3fdfc-788d-48ff, 2025.
Oschlies, A., Brandt, P., Stramma, L., and Schmidtko, S.: Drivers and mechanisms of ocean deoxygenation, Nature Geosci., 11, 467–473, https://doi.org/10.1038/s41561-018-0152-2, 2018.
Pascal, L., Cool, J., Archambault, P., Calosi, P., Cuenca, A. L. R., Mucci, A. O., and Chaillou, G.: Ocean deoxygenation caused non-linear responses in the structure and functioning of benthic ecosystems, Global Change Biology, 30, e16994, https://doi.org/10.1111/gcb.16994, 2024.
Pascal, L., Cloutier-Artiwat, F., Zanon, A., Wallace, D. W. R., and Chaillou, G.: New Deoxygenation Threshold for N2 and N2O Production in Coastal Waters and Sediments, Global Biogeochemical Cycles, 39, e2024GB008218, https://doi.org/10.1029/2024GB008218, 2025.
Rabalais, N. N. and Turner, R. E.: Gulf of Mexico Hypoxia: Past, Present, and Future, Limnology and Oceanography Bulletin, 28, 117–124, https://doi.org/10.1002/lob.10351, 2019.
Rabalais, N. N., Turner, R. E., and Wiseman Jr., W. J.: Hypoxia in the Gulf of Mexico, Journal of Environmental Quality, 30, 320–329, https://doi.org/10.2134/jeq2001.302320x, 2001.
Rabalais, N. N., Turner, R. E., and Wiseman Jr., W. J.: Gulf of Mexico Hypoxia, A.K.A. “The Dead Zone”, Annual Review of Ecology, Evolution, and Systematics, 33, 235–263, https://doi.org/10.1146/annurev.ecolsys.33.010802.150513, 2002.
Rabalais, N. N., Cai, W.-J., Carstensen, J., Conley, D. J., and Fry, B.: Eutrophication-Driven Deoxygenation in the Coastal Ocean, Oceanography, 27, 172–183, https://doi.org/10.5670/oceanog.2014.21, 2014.
Rakshit, S., Dale, A. W., Wallace, D. W., and Algar, C. K.: Sources and sinks of bottom water oxygen in a seasonally hypoxic fjord, Front. Mar. Sci., 10, https://doi.org/10.3389/fmars.2023.1148091, 2023.
Redfield, A. C., Ketchum, B., and Richards, F. A.: The influence of organisms on the composition of sea-water, in: The Sea, vol. 2, John Wiley & Sons, Ltd, United States of America, 26–77, 1963.
Robert, D.: Warming waters in the Gulf of St. Lawrence are disrupting commercial fishing, The Conversation, https://doi.org/10.64628/AAP.64mxjhvah, 16 November 2022.
Robinson, C. and Williams, P. J. L. B.: Respiration and its measurement in surface marine waters, in: Respiration in Aquatic Ecosystems, edited by: Del Giorgio, P. and Williams, P., Oxford University Press, 147–180, https://doi.org/10.1093/acprof:oso/9780198527084.003.0009, 2005.
Rousseau, S., Lavoie, D., Jutras, M., and Chassé, J.: Transit time of deep and intermediate waters in the Gulf of St. Lawrence, Ocean Modelling, 195, 102526, https://doi.org/10.1016/j.ocemod.2025.102526, 2025.
Savenkoff, C., Vézina, A. F., Packard, T. T., Silverberg, N., Therriault, J.-C., Chen, W., Bérubé, C., Mucci, A., Klein, B., Mesplé, F., Tremblay, J.-E., Legendre, L., Wesson, J., and Ingram, R. G.: Distributions of oxygen, carbon, and respiratory activity in the deep layer of the Gulf of St. Lawrence and their implications for the carbon cycle, Can. J. Fish. Aquat. Sci., 53, 2451–2465, https://doi.org/10.1139/f96-198, 1996.
Savenkoff, C., Vézina, A. F., Smith, P. C., and Han, G.: Summer Transports of Nutrients in the Gulf of St. Lawrence Estimated by Inverse Modelling, Estuarine, Coastal and Shelf Science, 52, 565–587, https://doi.org/10.1006/ecss.2001.0774, 2001.
Stevens, S. W., Pawlowicz, R., Tanhua, T., Gerke, L., Nesbitt, W. A., Drozdowski, A., Chassé, J., and Wallace, D. W. R.: Deep inflow transport and dispersion in the Gulf of St. Lawrence revealed by a tracer release experiment, Commun. Earth Environ., 5, 1–13, https://doi.org/10.1038/s43247-024-01505-5, 2024.
Stigebrandt, A., Liljebladh, B., de Brabandere, L., Forth, M., Granmo, Å., Hall, P., Hammar, J., Hansson, D., Kononets, M., Magnusson, M., Norén, F., Rahm, L., Treusch, A. H., and Viktorsson, L.: An Experiment with Forced Oxygenation of the Deepwater of the Anoxic By Fjord, Western Sweden, AMBIO, 44, 42–54, https://doi.org/10.1007/s13280-014-0524-9, 2015.
Su, J., Cai, W.-J., Hussain, N., Brodeur, J., Chen, B., and Huang, K.: Simultaneous determination of dissolved inorganic carbon (DIC) concentration and stable isotope (δ13C-DIC) by Cavity Ring-Down Spectroscopy: Application to study carbonate dynamics in the Chesapeake Bay, Marine Chemistry, 215, 103689, https://doi.org/10.1016/j.marchem.2019.103689, 2019.
Tang, C. L.: Cross-Front Mixing and Frontal Upwelling in a Controlled Quasi-Permanent Density Front in the Gulf of St. Lawrence, Journal of Physical Oceanography, 13, 1468–1481, https://doi.org/10.1175/1520-0485(1983)013<1468:CFMAFU>2.0.CO;2, 1983.
Tanioka, T. and Matsumoto, K.: Stability of Marine Organic Matter Respiration Stoichiometry, Geophysical Research Letters, 47, e2019GL085564, https://doi.org/10.1029/2019GL085564, 2020.
Testa, J. M., Clark, J. B., Dennison, W. C., Donovan, E. C., Fisher, A. W., Ni, W., Parker, M., Scavia, D., Spitzer, S. E., Waldrop, A. M., Vargas, V. M. D., and Ziegler, G.: Ecological Forecasting and the Science of Hypoxia in Chesapeake Bay, BioScience, 67, 614–626, https://doi.org/10.1093/biosci/bix048, 2017.
Thibodeau, B., de Vernal, A., and Mucci, A.: Recent eutrophication and consequent hypoxia in the bottom waters of the Lower St. Lawrence Estuary: Micropaleontological and geochemical evidence, Marine Geology, 231, 37–50, https://doi.org/10.1016/j.margeo.2006.05.010, 2006.
Thibodeau, B., de Vernal, A., Hillaire-Marcel, C., and Mucci, A.: Twentieth century warming in deep waters of the Gulf of St. Lawrence: A unique feature of the last millennium, Geophysical Research Letters, 37, https://doi.org/10.1029/2010GL044771, 2010.
Vaquer-Sunyer, R. and Duarte, C. M.: Thresholds of hypoxia for marine biodiversity, Proceedings of the National Academy of Sciences, 105, 15452–15457, https://doi.org/10.1073/pnas.0803833105, 2008.
Wallace, D. W. R., Jutras, M., Nesbitt, W. A., Donaldson, A., and Tanhua, T.: Can green hydrogen production be used to mitigate ocean deoxygenation? A scenario from the Gulf of St. Lawrence, Mitig. Adapt. Strateg. Glob. Change, 28, 56, https://doi.org/10.1007/s11027-023-10094-1, 2023.
Wang, Y., Ahad, J. M. E., Mucci, A. O., Gélinas, Y., and Douglas, P. M. J.: Large burial flux of modern organic carbon in the St. Lawrence estuarine system indicates a substantial atmospheric carbon sink, Earth and Planetary Science Letters, 652, 119204, https://doi.org/10.1016/j.epsl.2025.119204, 2025.
Wu, R. S. S.: Hypoxia: from molecular responses to ecosystem responses, Marine Pollution Bulletin, 45, 35–45, https://doi.org/10.1016/S0025-326X(02)00061-9, 2002.
Co-editor-in-chief
The reoxygenation of the traditional hypoxic deep water of Gulf of St. Lawrence is a novel topic; this has not been addressed in the past. If reoxygenation would be implemented, it would represent an encouraging effort in the midst of reports on the dire consequences of climate change and ocean deoxygenation.
The reoxygenation of the traditional hypoxic deep water of Gulf of St. Lawrence is a novel topic;...
Short summary
We combine two decades of oxygen data with new carbon observations and a tracer-informed model to quantify oxygen loss and carbon buildup in the deep waters of the Gulf and Lower St. Lawrence Estuary. We then test a novel idea: reoxygenating these waters with the oxygen produced as a by-product from green-hydrogen production. Our results suggest this could significantly reduce hypoxia, though full recovery would require larger inputs.
We combine two decades of oxygen data with new carbon observations and a tracer-informed model...
