Articles | Volume 17, issue 20
https://doi.org/10.5194/bg-17-4937-2020
© Author(s) 2020. 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-17-4937-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
16 Oct 2020
Research article |
| 16 Oct 2020
Using 226Ra and 228Ra isotopes to distinguish water mass distribution in the Canadian Arctic Archipelago
Chantal Mears
Department of Oceanography, Dalhousie University, Halifax, NS,
Canada
Institute for Coastal Research, Helmholtz Centre Geesthacht,
Geesthacht, Germany
Institute for Coastal Research, Helmholtz Centre Geesthacht,
Geesthacht, Germany
Department of Oceanography, Dalhousie University, Halifax, NS,
Canada
Paul B. Henderson
Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
Matthew A. Charette
Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
Hugh MacIntyre
Department of Oceanography, Dalhousie University, Halifax, NS,
Canada
Frank Dehairs
Analytical, Environmental and Geo-Chemistry,
Vrije Universiteit Brussel, Brussels, Belgium
Christophe Monnin
CNRS – Université Paul Sabatier-IRD-OMP, Geosciences
Environnement Toulouse (GET), Toulouse, France
Alfonso Mucci
Geotop and Department of Earth and Planetary Sciences, McGill
University, Montréal, QC, Canada
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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
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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.
Mona Norbisrath, Andreas Neumann, Kirstin Dähnke, Tina Sanders, Andreas Schöl, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences Discuss., https://doi.org/10.5194/bg-2022-226, https://doi.org/10.5194/bg-2022-226, 2022
Preprint under review for BG
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Total alkalinity (TA) is the oceanic capacity to store CO2. Estuaries can be a source for TA, by producing it by e.g., anaerobic metabolic pathways like denitrification (reduction of NO3- to N2), a major nitrogen (N) sink. Another important N sink is anammox, which transformes NH4+ with NO2- into N2. By combining TA and N2 production, we identified a TA source, denitrification occurring in the water column, and suggest anammox as the dominant N2 producer in the bottom layers of the Ems Estuary.
Mona Norbisrath, Johannes Pätsch, Kirstin Dähnke, Tina Sanders, Gesa Schulz, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 19, 5151–5165, https://doi.org/10.5194/bg-19-5151-2022, https://doi.org/10.5194/bg-19-5151-2022, 2022
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Total alkalinity (TA) regulates the oceanic storage capacity of atmospheric CO2. TA is also metabolically generated in estuaries and influences coastal carbon storage through its inflows. We used water samples and identified the Hamburg port area as the one with highest TA generation. Of the overall riverine TA load, 14 % is generated within the estuary. Using a biogeochemical model, we estimated potential effects on the coastal carbon storage under possible anthropogenic and climate changes.
Nele Lehmann, Hugues Lantuit, Michael Ernst Böttcher, Jens Hartmann, Antje Eulenburg, and Helmuth Thomas
Biogeosciences Discuss., https://doi.org/10.5194/bg-2022-205, https://doi.org/10.5194/bg-2022-205, 2022
Revised manuscript under review for BG
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Riverine alkalinity in the silicate-dominated headwater catchment at subarctic Iskorasfjellet, northern Norway, was almost entirely derived from weathering of minor carbonate occurrences in the riparian zone. The uphill catchment appeared limited by insufficient contact time of weathering agent and weatherable material. Further, alkalinity increased with decreasing permafrost extent. Thus, with climate change, alkalinity generation is expected to increase in this permafrost-degrading landscape.
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
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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.
Bryce Van Dam, Nele Lehmann, Mary A. Zeller, Andreas Neumann, Daniel Pröfrock, Marko Lipka, Helmuth Thomas, and Michael Ernst Böttcher
Biogeosciences, 19, 3775–3789, https://doi.org/10.5194/bg-19-3775-2022, https://doi.org/10.5194/bg-19-3775-2022, 2022
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We quantified sediment–water exchange at shallow sites in the North and Baltic seas. We found that porewater irrigation rates in the former were approximately twice as high as previously estimated, likely driven by relatively high bioirrigative activity. In contrast, we found small net fluxes of alkalinity, ranging from −35 µmol m−2 h−1 (uptake) to 53 µmol m−2 h−1 (release). We attribute this to low net denitrification, carbonate mineral (re-)precipitation, and sulfide (re-)oxidation.
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
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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.
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
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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.
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
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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.
Paul J. Tréguer, Jill N. Sutton, Mark Brzezinski, Matthew A. Charette, Timothy Devries, Stephanie Dutkiewicz, Claudia Ehlert, Jon Hawkings, Aude Leynaert, Su Mei Liu, Natalia Llopis Monferrer, María López-Acosta, Manuel Maldonado, Shaily Rahman, Lihua Ran, and Olivier Rouxel
Biogeosciences, 18, 1269–1289, https://doi.org/10.5194/bg-18-1269-2021, https://doi.org/10.5194/bg-18-1269-2021, 2021
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Silicon is the second most abundant element of the Earth's crust. In this review, we show that silicon inputs and outputs, to and from the world ocean, are 57 % and 37 % higher, respectively, than previous estimates. These changes are significant, modifying factors such as the geochemical residence time of silicon, which is now about 8000 years and 2 times faster than previously assumed. We also update the total biogenic silica pelagic production and provide an estimate for sponge production.
Fabian Schwichtenberg, Johannes Pätsch, Michael Ernst Böttcher, Helmuth Thomas, Vera Winde, and Kay-Christian Emeis
Biogeosciences, 17, 4223–4245, https://doi.org/10.5194/bg-17-4223-2020, https://doi.org/10.5194/bg-17-4223-2020, 2020
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Ocean acidification has a range of potentially harmful consequences for marine organisms. It is related to total alkalinity (TA) mainly produced in oxygen-poor situations like sediments in tidal flats. TA reduces the sensitivity of a water body to acidification. The decomposition of organic material and subsequent TA release in the tidal areas of the North Sea (Wadden Sea) is responsible for reduced acidification in the southern North Sea. This is shown with the results of an ecosystem model.
Alexis Beaupré-Laperrière, Alfonso Mucci, and Helmuth Thomas
Biogeosciences, 17, 3923–3942, https://doi.org/10.5194/bg-17-3923-2020, https://doi.org/10.5194/bg-17-3923-2020, 2020
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Ocean acidification is the process by which the oceans are changing due to carbon dioxide emissions from human activities. Studying this process in the Arctic Ocean is essential as this ocean and its ecosystems are more vulnerable to the effects of acidification. Water chemistry measurements made in recent years show that waters in and around the Canadian Arctic Archipelago are considerably affected by this process and show dynamic conditions that might have an impact on local marine organisms.
Louise Delaigue, Helmuth Thomas, and Alfonso Mucci
Biogeosciences, 17, 547–566, https://doi.org/10.5194/bg-17-547-2020, https://doi.org/10.5194/bg-17-547-2020, 2020
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This paper reports on the first compilation and analysis of the surface water pCO2 distribution in the Saguenay Fjord, the southernmost subarctic fjord in the Northern Hemisphere, and thus fills a significant knowledge gap in current regional estimates of estuarine CO2 emissions.
Robin Bénard, Maurice Levasseur, Michael Scarratt, Sonia Michaud, Michel Starr, Alfonso Mucci, Gustavo Ferreyra, Michel Gosselin, Jean-Éric Tremblay, Martine Lizotte, and Gui-Peng Yang
Biogeosciences, 16, 1167–1185, https://doi.org/10.5194/bg-16-1167-2019, https://doi.org/10.5194/bg-16-1167-2019, 2019
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We present rare data on the combined effects of acidification and warming on dimethylsulfide (DMS) during a mesocosm experiment. Our results show a reduction of DMS under elevated pCO2, but warming the mesocosms by 5 °C translated into a positive offset in concentrations of DMS over the whole range of pCO2 tested. Our results suggest that warming could mitigate the expected reduction in DMS production due to OA, even increasing the net DMS production, with possible repercussions for the climate.
Debany Fonseca-Batista, Xuefeng Li, Virginie Riou, Valérie Michotey, Florian Deman, François Fripiat, Sophie Guasco, Natacha Brion, Nolwenn Lemaitre, Manon Tonnard, Morgane Gallinari, Hélène Planquette, Frédéric Planchon, Géraldine Sarthou, Marc Elskens, Julie LaRoche, Lei Chou, and Frank Dehairs
Biogeosciences, 16, 999–1017, https://doi.org/10.5194/bg-16-999-2019, https://doi.org/10.5194/bg-16-999-2019, 2019
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Dinitrogen fixation and primary production were investigated using stable isotope incubation experiments along two transects off the Western Iberian Margin in May 2014 close to the end of the phytoplankton spring bloom. We observed substantial N2 fixation activities (up to 1533 µmol N m-2 d-1) associated with a predominance of unicellular cyanobacteria and non-cyanobacterial diazotrophs, which seemed to be promoted by the presence of bloom-derived organic matter and excess phosphorus.
Rachel M. Horwitz, Alex E. Hay, William J. Burt, Richard A. Cheel, Joseph Salisbury, and Helmuth Thomas
Biogeosciences, 16, 605–616, https://doi.org/10.5194/bg-16-605-2019, https://doi.org/10.5194/bg-16-605-2019, 2019
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High-frequency CO2 measurements are used to quantify the daily and tidal cycles of dissolved carbon in the Bay of Fundy – home to the world's largest tides. The oscillating tidal flows drive a net carbon transport, and these results suggest that previously unaccounted for tidal variation could substantially modulate the coastal ocean's response to global ocean acidification. Evaluating the impact of rising atmospheric CO2 on coastal systems requires understanding this short-term variability.
Géraldine Sarthou, Pascale Lherminier, Eric P. Achterberg, Fernando Alonso-Pérez, Eva Bucciarelli, Julia Boutorh, Vincent Bouvier, Edward A. Boyle, Pierre Branellec, Lidia I. Carracedo, Nuria Casacuberta, Maxi Castrillejo, Marie Cheize, Leonardo Contreira Pereira, Daniel Cossa, Nathalie Daniault, Emmanuel De Saint-Léger, Frank Dehairs, Feifei Deng, Floriane Desprez de Gésincourt, Jérémy Devesa, Lorna Foliot, Debany Fonseca-Batista, Morgane Gallinari, Maribel I. García-Ibáñez, Arthur Gourain, Emilie Grossteffan, Michel Hamon, Lars Eric Heimbürger, Gideon M. Henderson, Catherine Jeandel, Catherine Kermabon, François Lacan, Philippe Le Bot, Manon Le Goff, Emilie Le Roy, Alison Lefèbvre, Stéphane Leizour, Nolwenn Lemaitre, Pere Masqué, Olivier Ménage, Jan-Lukas Menzel Barraqueta, Herlé Mercier, Fabien Perault, Fiz F. Pérez, Hélène F. Planquette, Frédéric Planchon, Arnout Roukaerts, Virginie Sanial, Raphaëlle Sauzède, Catherine Schmechtig, Rachel U. Shelley, Gillian Stewart, Jill N. Sutton, Yi Tang, Nadine Tisnérat-Laborde, Manon Tonnard, Paul Tréguer, Pieter van Beek, Cheryl M. Zurbrick, and Patricia Zunino
Biogeosciences, 15, 7097–7109, https://doi.org/10.5194/bg-15-7097-2018, https://doi.org/10.5194/bg-15-7097-2018, 2018
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The GEOVIDE cruise (GEOTRACES Section GA01) was conducted in the North Atlantic Ocean and Labrador Sea in May–June 2014. In this special issue, results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 17 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.
Nolwenn Lemaitre, Frédéric Planchon, Hélène Planquette, Frank Dehairs, Debany Fonseca-Batista, Arnout Roukaerts, Florian Deman, Yi Tang, Clarisse Mariez, and Géraldine Sarthou
Biogeosciences, 15, 6417–6437, https://doi.org/10.5194/bg-15-6417-2018, https://doi.org/10.5194/bg-15-6417-2018, 2018
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We investigated the surface particulate organic carbon export fluxes in the North Atlantic with the objective of better understanding the biological carbon pump. Our results highlighted that exports depended on the intensity and stage of the bloom, the phytoplankton size and community structures. After comparing with primary production, we concluded that, during our study, the North Atlantic behaves like most of the highly productive areas in the world's ocean, with a low export efficiency.
Robin Bénard, Maurice Levasseur, Michael Scarratt, Marie-Amélie Blais, Alfonso Mucci, Gustavo Ferreyra, Michel Starr, Michel Gosselin, Jean-Éric Tremblay, and Martine Lizotte
Biogeosciences, 15, 4883–4904, https://doi.org/10.5194/bg-15-4883-2018, https://doi.org/10.5194/bg-15-4883-2018, 2018
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We investigated the combined effect of ocean acidification and warming on the dynamics of the phytoplankton fall boom in the Lower St. Lawrence Estuary, Canada. Twelve 2600 L mesocosms were used to cover a wide range of pH and two temperatures. We found that warming, rather than acidification, is more likely to alter the autumnal bloom in this estuary in the decades to come by stimulating the development and senescence of diatoms, and promoting picocyanobacteria proliferation.
Emilie Le Roy, Virginie Sanial, Matthew A. Charette, Pieter van Beek, François Lacan, Stéphanie H. M. Jacquet, Paul B. Henderson, Marc Souhaut, Maribel I. García-Ibáñez, Catherine Jeandel, Fiz F. Pérez, and Géraldine Sarthou
Biogeosciences, 15, 3027–3048, https://doi.org/10.5194/bg-15-3027-2018, https://doi.org/10.5194/bg-15-3027-2018, 2018
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We report detailed sections of radium-226 (226Ra, T1/2 = 1602 y) activities and barium (Ba) concentrations determined in the North Atlantic (Portugal–Greenland–Canada) in the framework of the international GEOTRACES program (GA01 section–GEOVIDE project, May–July 2014). Dissolved 226Ra and Ba are strongly correlated along the section, which may reflect their similar chemical behavior.
Nolwenn Lemaitre, Hélène Planquette, Frédéric Planchon, Géraldine Sarthou, Stéphanie Jacquet, Maribel I. García-Ibáñez, Arthur Gourain, Marie Cheize, Laurence Monin, Luc André, Priya Laha, Herman Terryn, and Frank Dehairs
Biogeosciences, 15, 2289–2307, https://doi.org/10.5194/bg-15-2289-2018, https://doi.org/10.5194/bg-15-2289-2018, 2018
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We present the particulate biogenic barium distributions in the North Atlantic for the first time with the objective of estimating mesopelagic carbon remineralisation fluxes. The remineralisation fluxes balanced or slightly exceeded the upper-ocean carbon export fluxes. This is a key result as the North Atlantic is generally assumed to be efficient in transferring carbon to the deep ocean, but during our study, the North Atlantic was characterized by a near-zero carbon sequestration efficiency.
Jonathan Lemay, Helmuth Thomas, Susanne E. Craig, William J. Burt, Katja Fennel, and Blair J. W. Greenan
Biogeosciences, 15, 2111–2123, https://doi.org/10.5194/bg-15-2111-2018, https://doi.org/10.5194/bg-15-2111-2018, 2018
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We report a detailed mechanistic investigation of the impact of Hurricane Arthur on the CO2 cycling on the Scotian Shelf. We can show that in contrast to common thinking, the deepening of the surface during the summer months can lead to increased CO2 uptake as carbon-poor waters from subsurface water are brought up to the surface. Only during prolonged storm events is the deepening of the mixed layer strong enough to bring the (expected) carbon-rich water to the surface.
Jacoba Mol, Helmuth Thomas, Paul G. Myers, Xianmin Hu, and Alfonso Mucci
Biogeosciences, 15, 1011–1027, https://doi.org/10.5194/bg-15-1011-2018, https://doi.org/10.5194/bg-15-1011-2018, 2018
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In the fall of 2014, the upwelling of water from the deep Canada Basin brought water onto the shallower Mackenzie Shelf in the Beaufort Sea. This increased the concentration of CO2 in water on the shelf, which alters pH and changes the transfer of CO2 between the ocean and atmosphere. These findings were a combined result of water sampling for CO2 parameters and the use of a computer model that simulates water movement in the ocean.
Ashley Dinauer and Alfonso Mucci
Biogeosciences, 14, 3221–3237, https://doi.org/10.5194/bg-14-3221-2017, https://doi.org/10.5194/bg-14-3221-2017, 2017
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Because of its large physical dimensions and unimpeded connection to the Atlantic Ocean, the St. Lawrence Gulf and Estuary encompass both estuarine and marine environments. The underlying physical and biogeochemical processes are reflected in the spatial pattern of surface-water pCO2 (139–765 µatm). The shallow partially mixed upper estuary was a CO2 source due to microbial respiration, whereas the deep stratified lower estuary was generally a CO2 sink due to phytoplankton photosynthesis.
Rachel Hussherr, Maurice Levasseur, Martine Lizotte, Jean-Éric Tremblay, Jacoba Mol, Helmuth Thomas, Michel Gosselin, Michel Starr, Lisa A. Miller, Tereza Jarniková, Nina Schuback, and Alfonso Mucci
Biogeosciences, 14, 2407–2427, https://doi.org/10.5194/bg-14-2407-2017, https://doi.org/10.5194/bg-14-2407-2017, 2017
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This study assesses the impact of ocean acidification on phytoplankton and its synthesis of the climate-active gas dimethyl sulfide (DMS), as well as its modulation, by two contrasting light regimes in the Arctic. The light regimes tested had no significant impact on either the phytoplankton or DMS concentration, whereas both variables decreased linearly with the decrease in pH. Thus, a rapid decrease in surface water pH could alter the algal biomass and inhibit DMS production in the Arctic.
William J. Burt, Helmuth Thomas, Lisa A. Miller, Mats A. Granskog, Tim N. Papakyriakou, and Leah Pengelly
Biogeosciences, 13, 4659–4671, https://doi.org/10.5194/bg-13-4659-2016, https://doi.org/10.5194/bg-13-4659-2016, 2016
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This study assesses the state of the carbon cycle in Hudson Bay, an ecologically important region of the Canadian Arctic. Results show that river input, sea-ice melt, biological activity, and general circulation patterns all have significant, and regionally dependent, impacts on the carbon cycle. The study also highlights the importance of detailed sampling procedures in highly stratified waters, and reveals that the deep Hudson Bay is primarily filled with waters of Pacific origin.
Fabian Große, Naomi Greenwood, Markus Kreus, Hermann-Josef Lenhart, Detlev Machoczek, Johannes Pätsch, Lesley Salt, and Helmuth Thomas
Biogeosciences, 13, 2511–2535, https://doi.org/10.5194/bg-13-2511-2016, https://doi.org/10.5194/bg-13-2511-2016, 2016
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We used the ECOHAM5 model to provide a consistent picture of the physical and biological drivers of oxygen deficiency in the North Sea. Regions susceptible to oxygen deficiency are characterised by low tidal mixing and moderate water depth (~ 40 m). Variations in upper layer productivity drive the year-to-year variability of bottom oxygen conditions. The model-based analysis reveals that benthic and pelagic remineralisation account for 90 % of bottom oxygen consumption observed at North Dogger.
A. J. Cavagna, F. Fripiat, M. Elskens, P. Mangion, L. Chirurgien, I. Closset, M. Lasbleiz, L. Florez-Leiva, D. Cardinal, K. Leblanc, C. Fernandez, D. Lefèvre, L. Oriol, S. Blain, B. Quéguiner, and F. Dehairs
Biogeosciences, 12, 6515–6528, https://doi.org/10.5194/bg-12-6515-2015, https://doi.org/10.5194/bg-12-6515-2015, 2015
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Primary production, NO3- and NH4+ uptake, and nitrification rates were measured during the KEOPS 2 cruise (austral spring 2011) in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production which is much higher in the fertilized areas compared to the HNLC site. We report high rates of nitrification in the mixed layer below the euphotic zone. We conclude that high productivity in deep mixing system stimulates the N cycle by increasing both assimilation and regeneration.
F. Planchon, D. Ballas, A.-J. Cavagna, A. R. Bowie, D. Davies, T. Trull, E. C. Laurenceau-Cornec, P. Van Der Merwe, and F. Dehairs
Biogeosciences, 12, 3831–3848, https://doi.org/10.5194/bg-12-3831-2015, https://doi.org/10.5194/bg-12-3831-2015, 2015
S. H. M. Jacquet, F. Dehairs, D. Lefèvre, A. J. Cavagna, F. Planchon, U. Christaki, L. Monin, L. André, I. Closset, and D. Cardinal
Biogeosciences, 12, 1713–1731, https://doi.org/10.5194/bg-12-1713-2015, https://doi.org/10.5194/bg-12-1713-2015, 2015
F. Dehairs, F. Fripiat, A.-J. Cavagna, T. W. Trull, C. Fernandez, D. Davies, A. Roukaerts, D. Fonseca Batista, F. Planchon, and M. Elskens
Biogeosciences, 12, 1459–1482, https://doi.org/10.5194/bg-12-1459-2015, https://doi.org/10.5194/bg-12-1459-2015, 2015
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We investigated the nitrate N, O isotopic composition for the Southern Ocean Kerguelen Plateau area, aiming at understanding the N-cycling in this naturally iron fertilized area characterized by large recurrent phytoplankton blooms. The system is characterized by moderate consumption of nitrate over the season while silicic acid, on the contrary, becomes depleted, suggesting significant recycling of N. Mixed layer nitrate isotopic signatures corroborate this.
T. W. Trull, D. M. Davies, F. Dehairs, A.-J. Cavagna, M. Lasbleiz, E. C. Laurenceau-Cornec, F. d'Ovidio, F. Planchon, K. Leblanc, B. Quéguiner, and S. Blain
Biogeosciences, 12, 1029–1056, https://doi.org/10.5194/bg-12-1029-2015, https://doi.org/10.5194/bg-12-1029-2015, 2015
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The KEOPS2 oceanographic study surveyed more than 30 sites downstream from the Kerguelen Islands in the Southern Ocean to examine the degree of variation in phytoplankton community responses to natural iron inputs. Our observations of community structure based on the chemical compositions of six microbial size fractions suggest that early spring trophodynamic and export responses differed between regions with persistently low levels versus punctually high levels of iron fertilisation.
M. L. González, V. Molina, L. Florez-Leiva, L. Oriol, A. J. Cavagna, F. Dehairs, L. Farias, and C. Fernandez
Biogeosciences Discuss., https://doi.org/10.5194/bgd-11-17151-2014, https://doi.org/10.5194/bgd-11-17151-2014, 2014
Revised manuscript not accepted
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This study shows for first time N2 fixation is occurring in the HNLC area of Southern Ocean and in naturally iron-fertilized waters, at rates exceeding previous reports for high latitudes (up to 20.11 nmol N L-1 d-1). Diazotrophs were identified as heterotrophic bacterioplankton; with an indirect role of dFe in the regulation of this process. Fertilization enhancing regenerated primary production may control N2 fixation via the availability od DOM for heterotrophic bacterioplankton.
C. Monnin, V. Chavagnac, C. Boulart, B. Ménez, M. Gérard, E. Gérard, C. Pisapia, M. Quéméneur, G. Erauso, A. Postec, L. Guentas-Dombrowski, C. Payri, and B. Pelletier
Biogeosciences, 11, 5687–5706, https://doi.org/10.5194/bg-11-5687-2014, https://doi.org/10.5194/bg-11-5687-2014, 2014
N. Jiao, C. Robinson, F. Azam, H. Thomas, F. Baltar, H. Dang, N. J. Hardman-Mountford, M. Johnson, D. L. Kirchman, B. P. Koch, L. Legendre, C. Li, J. Liu, T. Luo, Y.-W. Luo, A. Mitra, A. Romanou, K. Tang, X. Wang, C. Zhang, and R. Zhang
Biogeosciences, 11, 5285–5306, https://doi.org/10.5194/bg-11-5285-2014, https://doi.org/10.5194/bg-11-5285-2014, 2014
F. Tamooh, A. V. Borges, F. J. R. Meysman, K. Van Den Meersche, F. Dehairs, R. Merckx, and S. Bouillon
Biogeosciences, 10, 6911–6928, https://doi.org/10.5194/bg-10-6911-2013, https://doi.org/10.5194/bg-10-6911-2013, 2013
S. E. Craig, H. Thomas, C. T. Jones, W. K. W. Li, B. J. W. Greenan, E. H. Shadwick, and W. J. Burt
Biogeosciences Discuss., https://doi.org/10.5194/bgd-10-11255-2013, https://doi.org/10.5194/bgd-10-11255-2013, 2013
Revised manuscript not accepted
M. A. Charette, C. F. Breier, P. B. Henderson, S. M. Pike, I. I. Rypina, S. R. Jayne, and K. O. Buesseler
Biogeosciences, 10, 2159–2167, https://doi.org/10.5194/bg-10-2159-2013, https://doi.org/10.5194/bg-10-2159-2013, 2013
W. J. Burt, H. Thomas, K. Fennel, and E. Horne
Biogeosciences, 10, 53–66, https://doi.org/10.5194/bg-10-53-2013, https://doi.org/10.5194/bg-10-53-2013, 2013
Related subject area
Biogeochemistry: Coastal Ocean
Production and accumulation of reef framework by calcifying corals and macroalgae on a remote Indian Ocean cay
Zooplankton community succession and trophic links during a mesocosm experiment in the coastal upwelling off Callao Bay (Peru)
Temporal and spatial evolution of bottom-water hypoxia in the St Lawrence estuarine system
Significant nutrient consumption in the dark subsurface layer during a diatom bloom: a case study on Funka Bay, Hokkaido, Japan
Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf
Sediment quality assessment in an industrialized Greek coastal marine area (western Saronikos Gulf)
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed
Limits and CO2 equilibration of near-coast alkalinity enhancement
Role of phosphorus in the seasonal deoxygenation of the East China Sea shelf
Interannual variability of the initiation of the phytoplankton growing period in two French coastal ecosystems
Spatio-temporal distribution, photoreactivity and environmental control of dissolved organic matter in the sea-surface microlayer of the eastern marginal seas of China
Metabolic alkalinity release from large port facilities (Hamburg, Germany) and impact on coastal carbon storage
Impacts and uncertainties of climate-induced changes in watershed inputs on estuarine hypoxia
A Numerical reassessment of the Gulf of Mexico carbon system in connection with the Mississippi River and global ocean
Observed and projected global warming pressure on coastal hypoxia
Benthic alkalinity fluxes from coastal sediments of the Baltic and North seas: comparing approaches and identifying knowledge gaps
Investigating the effect of nickel concentration on phytoplankton growth to assess potential side-effects of ocean alkalinity enhancement
Unprecedented summer hypoxia in southern Cape Cod Bay: an ecological response to regional climate change?
Interannual variabilities, long-term trends, and regulating factors of low-oxygen conditions in the coastal waters off Hong Kong
Causes of the extensive hypoxia in the Gulf of Riga in 2018
Trawling effects on biogeochemical processes are mediated by fauna in high-energy biogenic-reef-inhabited coastal sediments
Drifting macrophyte detritus triggers ‘hidden’ benthic hypoxia
Drought recorded by Ba∕Ca in coastal benthic foraminifera
A nitrate budget of the Bohai Sea based on an isotope mass balance model
Suspended particulate matter drives the spatial segregation of nitrogen turnover along the hyper-turbid Ems estuary
Marine CO2 system variability along the northeast Pacific Inside Passage determined from an Alaskan ferry
Reviews and syntheses: Spatial and temporal patterns in seagrass metabolic fluxes
Mixed layer depth dominates over upwelling in regulating the seasonality of ecosystem functioning in the Peruvian upwelling system
Temporal dynamics of surface ocean carbonate chemistry in response to natural and simulated upwelling events during the 2017 coastal El Niño near Callao, Peru
Pelagic primary production in the coastal Mediterranean Sea: variability, trends, and contribution to basin-scale budgets
Contrasting patterns of carbon cycling and dissolved organic matter processing in two phytoplankton–bacteria communities
Biophysical controls on seasonal changes in the structure, growth, and grazing of the size-fractionated phytoplankton community in the northern South China Sea
Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton
Modeling cyanobacteria life cycle dynamics and historical nitrogen fixation in the Baltic Proper
Simultaneous assessment of oxygen- and nitrate-based net community production in a temperate shelf sea from a single ocean glider
Reviews and syntheses: Physical and biogeochemical processes associated with upwelling in the Indian Ocean
Particulate organic carbon dynamics in the Gulf of Lion shelf (NW Mediterranean) using a coupled hydrodynamic–biogeochemical model
Technical note: Novel triple O2 sensor aquatic eddy covariance instrument with improved time shift correction reveals central role of microphytobenthos for carbon cycling in coral reef sands
Long-term spatiotemporal variations in and expansion of low-oxygen conditions in the Pearl River estuary: a study synthesizing observations during 1976–2017
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula
Temporal variability and driving factors of the carbonate system in the Aransas Ship Channel, TX, USA: a time series study
Nitrogen loss processes in response to upwelling in a Peruvian coastal setting dominated by denitrification – a mesocosm approach
Retracing hypoxia in Eckernförde Bight (Baltic Sea)
The impact of the freeze–melt cycle of land-fast ice on the distribution of dissolved organic matter in the Laptev and East Siberian seas (Siberian Arctic)
The fate of upwelled nitrate off Peru shaped by submesoscale filaments and fronts
Coastal processes modify projections of some climate-driven stressors in the California Current System
Upwelling-induced trace gas dynamics in the Baltic Sea inferred from 8 years of autonomous measurements on a ship of opportunity
Destruction and reinstatement of coastal hypoxia in the South China Sea off the Pearl River estuary
Hypersaline tidal flats as important “blue carbon” systems: a case study from three ecosystems
Drivers and impact of the seasonal variability of the organic carbon offshore transport in the Canary upwelling system
M. James McLaughlin, Cindy Bessey, Gary A. Kendrick, John Keesing, and Ylva S. Olsen
Biogeosciences, 20, 1011–1026, https://doi.org/10.5194/bg-20-1011-2023, https://doi.org/10.5194/bg-20-1011-2023, 2023
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Coral reefs face increasing pressures from environmental change at present. The coral reef framework is produced by corals and calcifying algae. The Kimberley region of Western Australia has escaped land-based anthropogenic impacts. Specimens of the dominant coral and algae were collected from Browse Island's reef platform and incubated in mesocosms to measure calcification and production patterns of oxygen. This study provides important data on reef building and climate-driven effects.
Patricia Ayón Dejo, Elda Luz Pinedo Arteaga, Anna Schukat, Jan Taucher, Rainer Kiko, Helena Hauss, Sabrina Dorschner, Wilhelm Hagen, Mariona Segura-Noguera, and Silke Lischka
Biogeosciences, 20, 945–969, https://doi.org/10.5194/bg-20-945-2023, https://doi.org/10.5194/bg-20-945-2023, 2023
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Ocean upwelling regions are highly productive. With ocean warming, severe changes in upwelling frequency and/or intensity and expansion of accompanying oxygen minimum zones are projected. In a field experiment off Peru, we investigated how different upwelling intensities affect the pelagic food web and found failed reproduction of dominant zooplankton. The changes projected could severely impact the reproductive success of zooplankton communities and the pelagic food web in upwelling regions.
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
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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.
Sachi Umezawa, Manami Tozawa, Yuichi Nosaka, Daiki Nomura, Hiroji Onishi, Hiroto Abe, Tetsuya Takatsu, and Atsushi Ooki
Biogeosciences, 20, 421–438, https://doi.org/10.5194/bg-20-421-2023, https://doi.org/10.5194/bg-20-421-2023, 2023
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We conducted repetitive observations in Funka Bay, Japan, during the spring bloom 2019. We found nutrient concentration decreases in the dark subsurface layer during the bloom. Incubation experiments confirmed that diatoms could consume nutrients at a substantial rate, even in darkness. We concluded that the nutrient reduction was mainly caused by nutrient consumption by diatoms in the dark.
Dirk Jong, Lisa Bröder, Tommaso Tesi, Kirsi H. Keskitalo, Nikita Zimov, Anna Davydova, Philip Pika, Negar Haghipour, Timothy I. Eglinton, and Jorien E. Vonk
Biogeosciences, 20, 271–294, https://doi.org/10.5194/bg-20-271-2023, https://doi.org/10.5194/bg-20-271-2023, 2023
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With this study, we want to highlight the importance of studying both land and ocean together, and water and sediment together, as these systems function as a continuum, and determine how organic carbon derived from permafrost is broken down and its effect on global warming. Although on the one hand it appears that organic carbon is removed from sediments along the pathway of transport from river to ocean, it also appears to remain relatively ‘fresh’, despite this removal and its very old age.
Georgia Filippi, Manos Dassenakis, Vasiliki Paraskevopoulou, and Konstantinos Lazogiannis
Biogeosciences, 20, 163–189, https://doi.org/10.5194/bg-20-163-2023, https://doi.org/10.5194/bg-20-163-2023, 2023
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The pollution of the western Saronikos Gulf from heavy metals has been examined through the study of marine sediment cores. It is a deep gulf (maximum depth 440 m) near Athens affected by industrial and volcanic activity. Eight cores were received from various stations and depths and analysed for their heavy metal content and geochemical characteristics. The results were evaluated by using statistical methods, environmental indicators and comparisons with old data.
Linquan Mu, Jaime B. Palter, and Hongjie Wang
EGUsphere, https://doi.org/10.5194/egusphere-2022-1505, https://doi.org/10.5194/egusphere-2022-1505, 2023
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Enhancing ocean alkalinity accelerates carbon dioxide removal from the atmosphere. We hypothetically added alkalinity to the Amazon River and examined the increment of the carbon uptake by the Amazon plume. We also investigated the minimum alkalinity addition in which this perturbation at the river mouth could be detected above the natural variability.
Jing He and Michael D. Tyka
Biogeosciences, 20, 27–43, https://doi.org/10.5194/bg-20-27-2023, https://doi.org/10.5194/bg-20-27-2023, 2023
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Recently, ocean alkalinity enhancement (OAE) has gained interest as a scalable way to address the urgent need for negative CO2 emissions. In this paper we examine the capacity of different coastlines to tolerate alkalinity enhancement and the time scale of CO2 uptake following the addition of a given quantity of alkalinity. The results suggest that OAE has significant potential and identify specific favorable and unfavorable coastlines for its deployment.
Arnaud Laurent, Haiyan Zhang, and Katja Fennel
Biogeosciences, 19, 5893–5910, https://doi.org/10.5194/bg-19-5893-2022, https://doi.org/10.5194/bg-19-5893-2022, 2022
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The Changjiang is the main terrestrial source of nutrients to the East China Sea (ECS). Nutrient delivery to the ECS has been increasing since the 1960s, resulting in low oxygen (hypoxia) during phytoplankton decomposition in summer. River phosphorus (P) has increased less than nitrogen, and therefore, despite the large nutrient delivery, phytoplankton growth can be limited by the lack of P. Here, we investigate this link between P limitation, phytoplankton production/decomposition, and hypoxia.
Coline Poppeschi, Guillaume Charria, Anne Daniel, Romaric Verney, Peggy Rimmelin-Maury, Michaël Retho, Eric Goberville, Emilie Grossteffan, and Martin Plus
Biogeosciences, 19, 5667–5687, https://doi.org/10.5194/bg-19-5667-2022, https://doi.org/10.5194/bg-19-5667-2022, 2022
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This paper aims to understand interannual changes in the initiation of the phytoplankton growing period (IPGP) in the current context of global climate changes over the last 20 years. An important variability in the timing of the IPGP is observed with a trend towards a later IPGP during this last decade. The role and the impact of extreme events (cold spells, floods, and wind burst) on the IPGP is also detailed.
Lin Yang, Jing Zhang, Anja Engel, and Gui-Peng Yang
Biogeosciences, 19, 5251–5268, https://doi.org/10.5194/bg-19-5251-2022, https://doi.org/10.5194/bg-19-5251-2022, 2022
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Enrichment factors of dissolved organic matter (DOM) in the eastern marginal seas of China exhibited a significant spatio-temporal variation. Photochemical and enrichment processes co-regulated DOM enrichment in the sea-surface microlayer (SML). Autochthonous DOM was more frequently enriched in the SML than terrestrial DOM. DOM in the sub-surface water exhibited higher aromaticity than that in the SML.
Mona Norbisrath, Johannes Pätsch, Kirstin Dähnke, Tina Sanders, Gesa Schulz, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 19, 5151–5165, https://doi.org/10.5194/bg-19-5151-2022, https://doi.org/10.5194/bg-19-5151-2022, 2022
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Total alkalinity (TA) regulates the oceanic storage capacity of atmospheric CO2. TA is also metabolically generated in estuaries and influences coastal carbon storage through its inflows. We used water samples and identified the Hamburg port area as the one with highest TA generation. Of the overall riverine TA load, 14 % is generated within the estuary. Using a biogeochemical model, we estimated potential effects on the coastal carbon storage under possible anthropogenic and climate changes.
Kyle E. Hinson, Marjorie A. M. Friedrichs, Raymond G. Najjar, Maria Herrmann, Zihao Bian, Gopal Bhatt, Pierre St-Laurent, Hanqin Tian, and Gary Shenk
EGUsphere, https://doi.org/10.5194/egusphere-2022-1028, https://doi.org/10.5194/egusphere-2022-1028, 2022
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Climate impacts are essential for environmental managers to consider when implementing nutrient reduction plans designed to reduce hypoxia. This work highlights relative sources of uncertainty in modeling regional climate impacts on the Chesapeake Bay watershed and consequent declines in Bay oxygen levels. The results demonstrate that planned water quality improvement goals are capable of reducing hypoxia levels by half, offsetting climate-driven impacts to terrestrial runoff.
Le Zhang and Z. George Xue
Biogeosciences, 19, 4589–4618, https://doi.org/10.5194/bg-19-4589-2022, https://doi.org/10.5194/bg-19-4589-2022, 2022
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We adopt a high-resolution carbon model for the Gulf of Mexico (GoM) and calculate the decadal trends of important carbon system variables in the GoM from 2001 to 2019. The GoM surface CO2 values experienced a steady increase over the past 2 decades, and the ocean surface pH is declining. Although carbonate saturation rates remain supersaturated with aragonite, they show a slightly decreasing trend. The northern GoM is a stronger carbon sink than we thought.
Michael M. Whitney
Biogeosciences, 19, 4479–4497, https://doi.org/10.5194/bg-19-4479-2022, https://doi.org/10.5194/bg-19-4479-2022, 2022
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Coastal hypoxia is a major environmental problem of increasing severity. The 21st-century projections analyzed indicate global coastal waters will warm and experience rapid declines in oxygen. The forecasted median coastal trends for increasing sea surface temperature and decreasing oxygen capacity are 48 % and 18 % faster than the rates observed over the last 4 decades. Existing hypoxic areas are expected to worsen, and new hypoxic areas likely will emerge under these warming-related pressures.
Bryce Van Dam, Nele Lehmann, Mary A. Zeller, Andreas Neumann, Daniel Pröfrock, Marko Lipka, Helmuth Thomas, and Michael Ernst Böttcher
Biogeosciences, 19, 3775–3789, https://doi.org/10.5194/bg-19-3775-2022, https://doi.org/10.5194/bg-19-3775-2022, 2022
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We quantified sediment–water exchange at shallow sites in the North and Baltic seas. We found that porewater irrigation rates in the former were approximately twice as high as previously estimated, likely driven by relatively high bioirrigative activity. In contrast, we found small net fluxes of alkalinity, ranging from −35 µmol m−2 h−1 (uptake) to 53 µmol m−2 h−1 (release). We attribute this to low net denitrification, carbonate mineral (re-)precipitation, and sulfide (re-)oxidation.
Jiaying Abby Guo, Robert Strzepek, Anusuya Willis, Aaron Ferderer, and Lennart Thomas Bach
Biogeosciences, 19, 3683–3697, https://doi.org/10.5194/bg-19-3683-2022, https://doi.org/10.5194/bg-19-3683-2022, 2022
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Ocean alkalinity enhancement is a CO2 removal method with significant potential, but it can lead to a perturbation of the ocean with trace metals such as nickel. This study tested the effect of increasing nickel concentrations on phytoplankton growth and photosynthesis. We found that the response to nickel varied across the 11 phytoplankton species tested here, but the majority were rather insensitive. We note, however, that responses may be different under other experimental conditions.
Malcolm E. Scully, W. Rockwell Geyer, David Borkman, Tracy L. Pugh, Amy Costa, and Owen C. Nichols
Biogeosciences, 19, 3523–3536, https://doi.org/10.5194/bg-19-3523-2022, https://doi.org/10.5194/bg-19-3523-2022, 2022
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For two consecutive summers, the bottom waters in southern Cape Cod Bay became severely depleted of dissolved oxygen. Low oxygen levels in bottom waters have never been reported in this area before, and this unprecedented occurrence is likely the result of a new algae species that recently began blooming during the late-summer months. We present data suggesting that blooms of this new species are the result of regional climate change including warmer waters and changes in summer winds.
Zheng Chen, Bin Wang, Chuang Xu, Zhongren Zhang, Shiyu Li, and Jiatang Hu
Biogeosciences, 19, 3469–3490, https://doi.org/10.5194/bg-19-3469-2022, https://doi.org/10.5194/bg-19-3469-2022, 2022
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Deterioration of low-oxygen conditions in the coastal waters off Hong Kong was revealed by monitoring data over two decades. The declining wind forcing and the increasing nutrient input contributed significantly to the areal expansion and intense deterioration of low-oxygen conditions. Also, the exacerbated eutrophication drove a shift in the dominant source of organic matter from terrestrial inputs to in situ primary production, which has probably led to an earlier onset of hypoxia in summer.
Stella-Theresa Stoicescu, Jaan Laanemets, Taavi Liblik, Māris Skudra, Oliver Samlas, Inga Lips, and Urmas Lips
Biogeosciences, 19, 2903–2920, https://doi.org/10.5194/bg-19-2903-2022, https://doi.org/10.5194/bg-19-2903-2022, 2022
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Coastal basins with high input of nutrients often suffer from oxygen deficiency. In summer 2018, the extent of oxygen depletion was exceptional in the Gulf of Riga. We analyzed observational data and found that extensive oxygen deficiency appeared since the water layer close to the seabed, where oxygen is consumed, was separated from the surface layer. The problem worsens if similar conditions restricting vertical transport of oxygen occur more frequently in the future.
Justin C. Tiano, Jochen Depestele, Gert Van Hoey, João Fernandes, Pieter van Rijswijk, and Karline Soetaert
Biogeosciences, 19, 2583–2598, https://doi.org/10.5194/bg-19-2583-2022, https://doi.org/10.5194/bg-19-2583-2022, 2022
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This study gives an assessment of bottom trawling on physical, chemical, and biological characteristics in a location known for its strong currents and variable habitats. Although trawl gears only removed the top 1 cm of the seabed surface, impacts on reef-building tubeworms significantly decreased carbon and nutrient cycling. Lighter trawls slightly reduced the impact on fauna and nutrients. Tubeworms were strongly linked to biogeochemical and faunal aspects before but not after trawling.
Karl Michael Attard, Anna Lyssenko, and Iván Franco Rodil
Biogeosciences Discuss., https://doi.org/10.5194/bg-2022-119, https://doi.org/10.5194/bg-2022-119, 2022
Revised manuscript accepted for BG
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Aquatic plants produce a large amount of organic matter through photosynthesis that, following seasonal decay or storms, is deposited on the seafloor. In this study, we show that plant detritus can trigger low oxygen conditions (hypoxia) in shallow coastal waters, making conditions challenging for most marine animals. We propose that the occurrence of hypoxia may be underestimated because measurements typically do not consider the region closest to the seafloor, where detritus accumulates.
Inda Brinkmann, Christine Barras, Tom Jilbert, Tomas Næraa, K. Mareike Paul, Magali Schweizer, and Helena L. Filipsson
Biogeosciences, 19, 2523–2535, https://doi.org/10.5194/bg-19-2523-2022, https://doi.org/10.5194/bg-19-2523-2022, 2022
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The concentration of the trace metal barium (Ba) in coastal seawater is a function of continental input, such as riverine discharge. Our geochemical records of the severely hot and dry year 2018, and following wet year 2019, reveal that prolonged drought imprints with exceptionally low Ba concentrations in benthic foraminiferal calcium carbonates of coastal sediments. This highlights the potential of benthic Ba / Ca to trace past climate extremes and variability in coastal marine records.
Shichao Tian, Birgit Gaye, Jianhui Tang, Yongming Luo, Wenguo Li, Niko Lahajnar, Kirstin Dähnke, Tina Sanders, Tianqi Xiong, Weidong Zhai, and Kay-Christian Emeis
Biogeosciences, 19, 2397–2415, https://doi.org/10.5194/bg-19-2397-2022, https://doi.org/10.5194/bg-19-2397-2022, 2022
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We constrain the nitrogen budget and in particular the internal sources and sinks of nitrate in the Bohai Sea by using a mass-based and dual stable isotope approach based on δ15N and δ18O of nitrate. Based on available mass fluxes and isotope data an updated nitrogen budget is proposed. Compared to previous estimates, it is more complete and includes the impact of the interior cycle (nitrification) on the nitrate pool. The main external nitrogen sources are rivers contributing 19.2 %–25.6 %.
Gesa Schulz, Tina Sanders, Justus E. E. van Beusekom, Yoana G. Voynova, Andreas Schöl, and Kirstin Dähnke
Biogeosciences, 19, 2007–2024, https://doi.org/10.5194/bg-19-2007-2022, https://doi.org/10.5194/bg-19-2007-2022, 2022
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Estuaries can significantly alter nutrient loads before reaching coastal waters. Our study of the heavily managed Ems estuary (Northern Germany) reveals three zones of nitrogen turnover along the estuary with water-column denitrification in the most upstream hyper-turbid part, nitrate production in the middle reaches and mixing/nitrate uptake in the North Sea. Suspended particulate matter was the overarching control on nitrogen cycling in the hyper-turbid estuary.
Wiley Evans, Geoffrey T. Lebon, Christen D. Harrington, Yuichiro Takeshita, and Allison Bidlack
Biogeosciences, 19, 1277–1301, https://doi.org/10.5194/bg-19-1277-2022, https://doi.org/10.5194/bg-19-1277-2022, 2022
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Information on the marine carbon dioxide system along the northeast Pacific Inside Passage has been limited. To address this gap, we instrumented an Alaskan ferry in order to characterize the marine carbon dioxide system in this region. Data over a 2-year period were used to assess drivers of the observed variability, identify the timing of severe conditions, and assess the extent of contemporary ocean acidification as well as future levels consistent with a 1.5 °C warmer climate.
Melissa Ward, Tye L. Kindinger, Heidi K. Hirsh, Tessa M. Hill, Brittany M. Jellison, Sarah Lummis, Emily B. Rivest, George G. Waldbusser, Brian Gaylord, and Kristy J. Kroeker
Biogeosciences, 19, 689–699, https://doi.org/10.5194/bg-19-689-2022, https://doi.org/10.5194/bg-19-689-2022, 2022
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Here, we synthesize the results from 62 studies reporting in situ rates of seagrass metabolism to highlight spatial and temporal variability in oxygen fluxes and inform efforts to use seagrass to mitigate ocean acidification. Our analyses suggest seagrass meadows are generally autotrophic and variable in space and time, and the effects on seawater oxygen are relatively small in magnitude.
Tianfei Xue, Ivy Frenger, A. E. Friederike Prowe, Yonss Saranga José, and Andreas Oschlies
Biogeosciences, 19, 455–475, https://doi.org/10.5194/bg-19-455-2022, https://doi.org/10.5194/bg-19-455-2022, 2022
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The Peruvian system supports 10 % of the world's fishing yield. In the Peruvian system, wind and earth’s rotation bring cold, nutrient-rich water to the surface and allow phytoplankton to grow. But observations show that it grows worse at high upwelling. Using a model, we find that high upwelling happens when air mixes the water the most. Then phytoplankton is diluted and grows slowly due to low light and cool upwelled water. This study helps to estimate how it might change in a warming climate.
Shao-Min Chen, Ulf Riebesell, Kai G. Schulz, Elisabeth von der Esch, Eric P. Achterberg, and Lennart T. Bach
Biogeosciences, 19, 295–312, https://doi.org/10.5194/bg-19-295-2022, https://doi.org/10.5194/bg-19-295-2022, 2022
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Oxygen minimum zones in the ocean are characterized by enhanced carbon dioxide (CO2) levels and are being further acidified by increasing anthropogenic atmospheric CO2. Here we report CO2 system measurements in a mesocosm study offshore Peru during a rare coastal El Niño event to investigate how CO2 dynamics may respond to ongoing ocean deoxygenation. Our observations show that nitrogen limitation, productivity, and plankton community shift play an important role in driving the CO2 dynamics.
Paula Maria Salgado-Hernanz, Aurore Regaudie-de-Gioux, David Antoine, and Gotzon Basterretxea
Biogeosciences, 19, 47–69, https://doi.org/10.5194/bg-19-47-2022, https://doi.org/10.5194/bg-19-47-2022, 2022
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For the first time, this study presents the characteristics of primary production in coastal regions of the Mediterranean Sea based on satellite-borne observations for the period 2002–2016. The study concludes that there are significant spatial and temporal variations among different regions. Quantifying primary production is of special importance in the marine food web and in the sequestration of carbon dioxide from the atmosphere to the deep waters.
Samu Elovaara, Eeva Eronen-Rasimus, Eero Asmala, Tobias Tamelander, and Hermanni Kaartokallio
Biogeosciences, 18, 6589–6616, https://doi.org/10.5194/bg-18-6589-2021, https://doi.org/10.5194/bg-18-6589-2021, 2021
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Dissolved organic matter (DOM) is a significant carbon pool in the marine environment. The composition of the DOM pool, as well as its interaction with microbes, is complex, yet understanding it is important for understanding global carbon cycling. This study shows that two phytoplankton species have different effects on the composition of the DOM pool and, through the DOM they produce, on the ensuing microbial community. These communities in turn have different effects on DOM composition.
Yuan Dong, Qian P. Li, Zhengchao Wu, Yiping Shuai, Zijia Liu, Zaiming Ge, Weiwen Zhou, and Yinchao Chen
Biogeosciences, 18, 6423–6434, https://doi.org/10.5194/bg-18-6423-2021, https://doi.org/10.5194/bg-18-6423-2021, 2021
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Temporal change of plankton growth and grazing are less known in the coastal ocean, not to mention the relevant controlling mechanisms. Here, we performed monthly size-specific dilution experiments outside a eutrophic estuary over a 1-year cycle. Phytoplankton growth was correlated to nutrients and grazing mortality to total chlorophyll a. A selective grazing on small cells may be important for maintaining high abundance of large-chain-forming diatoms in this eutrophic system.
Kiefer O. Forsch, Lisa Hahn-Woernle, Robert M. Sherrell, Vincent J. Roccanova, Kaixuan Bu, David Burdige, Maria Vernet, and Katherine A. Barbeau
Biogeosciences, 18, 6349–6375, https://doi.org/10.5194/bg-18-6349-2021, https://doi.org/10.5194/bg-18-6349-2021, 2021
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We show that for an unperturbed cold western Antarctic Peninsula fjord, the seasonality of iron and manganese is linked to the dispersal of metal-rich meltwater sources. Geochemical measurements of trace metals in meltwaters, porewaters, and seawater, collected during two expeditions, showed a seasonal cycle of distinct sources. Finally, model results revealed that the dispersal of surface meltwater and meltwater plumes originating from under the glacier is sensitive to katabatic wind events.
Jenny Hieronymus, Kari Eilola, Malin Olofsson, Inga Hense, H. E. Markus Meier, and Elin Almroth-Rosell
Biogeosciences, 18, 6213–6227, https://doi.org/10.5194/bg-18-6213-2021, https://doi.org/10.5194/bg-18-6213-2021, 2021
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Dense blooms of cyanobacteria occur every summer in the Baltic Proper and can add to eutrophication by their ability to turn nitrogen gas into dissolved inorganic nitrogen. Being able to correctly estimate the size of this nitrogen fixation is important for management purposes. In this work, we find that the life cycle of cyanobacteria plays an important role in capturing the seasonality of the blooms as well as the size of nitrogen fixation in our ocean model.
Tom Hull, Naomi Greenwood, Antony Birchill, Alexander Beaton, Matthew Palmer, and Jan Kaiser
Biogeosciences, 18, 6167–6180, https://doi.org/10.5194/bg-18-6167-2021, https://doi.org/10.5194/bg-18-6167-2021, 2021
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The shallow shelf seas play a large role in the global cycling of CO2 and also support large fisheries. We use an autonomous underwater vehicle in the central North Sea to measure the rates of change in oxygen and nutrients.
Using these data we determine the amount of carbon dioxide taken out of the atmosphere by the sea and measure how productive the region is.
These observations will be useful for improving our predictive models and help us predict and adapt to a changing ocean.
Puthenveettil Narayana Menon Vinayachandran, Yukio Masumoto, Michael J. Roberts, Jenny A. Huggett, Issufo Halo, Abhisek Chatterjee, Prakash Amol, Garuda V. M. Gupta, Arvind Singh, Arnab Mukherjee, Satya Prakash, Lynnath E. Beckley, Eric Jorden Raes, and Raleigh Hood
Biogeosciences, 18, 5967–6029, https://doi.org/10.5194/bg-18-5967-2021, https://doi.org/10.5194/bg-18-5967-2021, 2021
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Upwelling in the coastal ocean triggers biological productivity and thus enhances fisheries. Therefore, understanding the phenomenon of upwelling and the underlying mechanisms is important. In this paper, the present understanding of the upwelling along the coastline of the Indian Ocean from the coast of Africa all the way up to the coast of Australia is reviewed. The review provides a synthesis of the physical processes associated with upwelling and its impact on the marine ecosystem.
Gaël Many, Caroline Ulses, Claude Estournel, and Patrick Marsaleix
Biogeosciences, 18, 5513–5538, https://doi.org/10.5194/bg-18-5513-2021, https://doi.org/10.5194/bg-18-5513-2021, 2021
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The Gulf of Lion shelf is one of the most productive areas in the Mediterranean. A model is used to study the mechanisms that drive the particulate organic carbon (POC). The model reproduces the annual cycle of primary production well. The shelf appears as an autotrophic ecosystem with a high production and as a source of POC for the adjacent basin. The increase in temperature induced by climate change could impact the trophic status of the shelf.
Alireza Merikhi, Peter Berg, and Markus Huettel
Biogeosciences, 18, 5381–5395, https://doi.org/10.5194/bg-18-5381-2021, https://doi.org/10.5194/bg-18-5381-2021, 2021
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The aquatic eddy covariance technique is a powerful method for measurements of solute fluxes across the sediment–water interface. Data measured by conventional eddy covariance instruments require a time shift correction that can result in substantial flux errors. We introduce a triple O2 sensor eddy covariance instrument that by design eliminates these errors. Deployments next to a conventional instrument in the Florida Keys demonstrate the improvements achieved through the new design.
Jiatang Hu, Zhongren Zhang, Bin Wang, and Jia Huang
Biogeosciences, 18, 5247–5264, https://doi.org/10.5194/bg-18-5247-2021, https://doi.org/10.5194/bg-18-5247-2021, 2021
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In situ observations over 42 years were used to explore the long-term changes to low-oxygen conditions in the Pearl River estuary. Apparent expansion of the low-oxygen conditions in summer was identified, primarily due to the combined effects of increased anthropogenic inputs and decreased sediment load. Large areas of severe low-oxygen events were also observed in early autumn and were formed by distinct mechanisms. The estuary seems to be growing into a seasonal, estuary-wide hypoxic zone.
Indah Ardiningsih, Kyyas Seyitmuhammedov, Sylvia G. Sander, Claudine H. Stirling, Gert-Jan Reichart, Kevin R. Arrigo, Loes J. A. Gerringa, and Rob Middag
Biogeosciences, 18, 4587–4601, https://doi.org/10.5194/bg-18-4587-2021, https://doi.org/10.5194/bg-18-4587-2021, 2021
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Organic Fe speciation is investigated along a natural gradient of the western Antarctic Peninsula from an ice-covered shelf to the open ocean. The two major fronts in the region affect the distribution of ligands. The excess ligands not bound to dissolved Fe (DFe) comprised up to 80 % of the total ligand concentrations, implying the potential to solubilize additional Fe input. The ligands on the shelf can increase the DFe residence time and fuel local primary production upon ice melt.
Melissa R. McCutcheon, Hongming Yao, Cory J. Staryk, and Xinping Hu
Biogeosciences, 18, 4571–4586, https://doi.org/10.5194/bg-18-4571-2021, https://doi.org/10.5194/bg-18-4571-2021, 2021
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We used 5+ years of discrete samples and 10 months of hourly sensor measurements to explore temporal variability and environmental controls on pH and pCO2 at the Aransas Ship Channel. Seasonal and diel variability were both present but small compared to other regions in the literature. Despite the small tidal range, tidal control often surpassed biological control. In comparison with sensor data, discrete samples were generally representative of mean annual and seasonal carbonate chemistry.
Kai G. Schulz, Eric P. Achterberg, Javier Arístegui, Lennart T. Bach, Isabel Baños, Tim Boxhammer, Dirk Erler, Maricarmen Igarza, Verena Kalter, Andrea Ludwig, Carolin Löscher, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Elisabeth von der Esch, Bess B. Ward, and Ulf Riebesell
Biogeosciences, 18, 4305–4320, https://doi.org/10.5194/bg-18-4305-2021, https://doi.org/10.5194/bg-18-4305-2021, 2021
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Upwelling of nutrient-rich deep waters to the surface make eastern boundary upwelling systems hot spots of marine productivity. This leads to subsurface oxygen depletion and the transformation of bioavailable nitrogen into inert N2. Here we quantify nitrogen loss processes following a simulated deep water upwelling. Denitrification was the dominant process, and budget calculations suggest that a significant portion of nitrogen that could be exported to depth is already lost in the surface ocean.
Heiner Dietze and Ulrike Löptien
Biogeosciences, 18, 4243–4264, https://doi.org/10.5194/bg-18-4243-2021, https://doi.org/10.5194/bg-18-4243-2021, 2021
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In recent years fish-kill events caused by oxygen deficit have been reported in Eckernförde Bight (Baltic Sea). This study sets out to understand the processes causing respective oxygen deficits by combining high-resolution coupled ocean circulation biogeochemical modeling, monitoring data, and artificial intelligence.
Jens A. Hölemann, Bennet Juhls, Dorothea Bauch, Markus Janout, Boris P. Koch, and Birgit Heim
Biogeosciences, 18, 3637–3655, https://doi.org/10.5194/bg-18-3637-2021, https://doi.org/10.5194/bg-18-3637-2021, 2021
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The Arctic Ocean receives large amounts of river water rich in terrestrial dissolved organic matter (tDOM), which is an important component of the Arctic carbon cycle. Our analysis shows that mixing of three major freshwater sources is the main factor that regulates the distribution of tDOM concentrations in the Siberian shelf seas. In this context, the formation and melting of the land-fast ice in the Laptev Sea and the peak spring discharge of the Lena River are of particular importance.
Jaard Hauschildt, Soeren Thomsen, Vincent Echevin, Andreas Oschlies, Yonss Saranga José, Gerd Krahmann, Laura A. Bristow, and Gaute Lavik
Biogeosciences, 18, 3605–3629, https://doi.org/10.5194/bg-18-3605-2021, https://doi.org/10.5194/bg-18-3605-2021, 2021
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In this paper we quantify the subduction of upwelled nitrate due to physical processes on the order of several kilometers in the coastal upwelling off Peru and its effect on primary production. We also compare the prepresentation of these processes in a high-resolution simulation (~2.5 km) with a more coarsely resolved simulation (~12 km). To do this, we combine high-resolution shipboard observations of physical and biogeochemical parameters with a complex biogeochemical model configuration.
Samantha A. Siedlecki, Darren Pilcher, Evan M. Howard, Curtis Deutsch, Parker MacCready, Emily L. Norton, Hartmut Frenzel, Jan Newton, Richard A. Feely, Simone R. Alin, and Terrie Klinger
Biogeosciences, 18, 2871–2890, https://doi.org/10.5194/bg-18-2871-2021, https://doi.org/10.5194/bg-18-2871-2021, 2021
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Future ocean conditions can be simulated using projected trends in fossil fuel use paired with Earth system models. Global models generally do not include local processes important to coastal ecosystems. These coastal processes can alter the degree of change projected. Higher-resolution models that include local processes predict modified changes in carbon stressors when compared to changes projected by global models in the California Current System.
Erik Jacobs, Henry C. Bittig, Ulf Gräwe, Carolyn A. Graves, Michael Glockzin, Jens D. Müller, Bernd Schneider, and Gregor Rehder
Biogeosciences, 18, 2679–2709, https://doi.org/10.5194/bg-18-2679-2021, https://doi.org/10.5194/bg-18-2679-2021, 2021
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We use a unique data set of 8 years of continuous carbon dioxide (CO2) and methane (CH4) surface water measurements from a commercial ferry to study upwelling in the Baltic Sea. Its seasonality and regional and interannual variability are examined. Strong upwelling events drastically increase local surface CO2 and CH4 levels and are mostly detected in late summer after long periods of impaired mixing. We introduce an extrapolation method to estimate regional upwelling-induced trace gas fluxes.
Yangyang Zhao, Khanittha Uthaipan, Zhongming Lu, Yan Li, Jing Liu, Hongbin Liu, Jianping Gan, Feifei Meng, and Minhan Dai
Biogeosciences, 18, 2755–2775, https://doi.org/10.5194/bg-18-2755-2021, https://doi.org/10.5194/bg-18-2755-2021, 2021
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In situ oxygen consumption rates were estimated for the first time during destruction of coastal hypoxia as disturbed by a typhoon and its reinstatement in the South China Sea off the Pearl River estuary. The reinstatement of summer hypoxia was rapid with a comparable timescale with that of its initial disturbance from frequent tropical cyclones, which has important implications for better understanding the intermittent nature of coastal hypoxia and its prediction in a changing climate.
Dylan R. Brown, Humberto Marotta, Roberta B. Peixoto, Alex Enrich-Prast, Glenda C. Barroso, Mario L. G. Soares, Wilson Machado, Alexander Pérez, Joseph M. Smoak, Luciana M. Sanders, Stephen Conrad, James Z. Sippo, Isaac R. Santos, Damien T. Maher, and Christian J. Sanders
Biogeosciences, 18, 2527–2538, https://doi.org/10.5194/bg-18-2527-2021, https://doi.org/10.5194/bg-18-2527-2021, 2021
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Hypersaline tidal flats (HTFs) are coastal ecosystems with freshwater deficits often occurring in arid or semi-arid regions near mangrove supratidal zones with no major fluvial contributions. This study shows that HTFs are important carbon and nutrient sinks which may be significant given their extensive coverage. Our findings highlight a previously unquantified carbon as well as a nutrient sink and suggest that coastal HTF ecosystems could be included in the emerging blue carbon framework.
Giulia Bonino, Elisa Lovecchio, Nicolas Gruber, Matthias Münnich, Simona Masina, and Doroteaciro Iovino
Biogeosciences, 18, 2429–2448, https://doi.org/10.5194/bg-18-2429-2021, https://doi.org/10.5194/bg-18-2429-2021, 2021
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Seasonal variations of processes such as upwelling and biological production that happen along the northwestern African coast can modulate the temporal variability of the biological activity of the adjacent open North Atlantic hundreds of kilometers away from the coast thanks to the lateral transport of coastal organic carbon. This happens with a temporal delay, which is smaller than a season up to roughly 500 km from the coast due to the intense transport by small-scale filaments.
Cited articles
Aagaard, K. and Carmack, E. C.: The role of sea ice and other fresh water in
the Arctic circulation, J. Geophys. Res., 94, 14485,
https://doi.org/10.1029/JC094iC10p14485, 1989.
Aagaard, K. and Carmack, E. C.: The Arctic Ocean and Climate: A Perspective,
in The Polar Oceans and Their Role in Shaping the Global Environment, Geophys. Monogr. Ser., vol. 85, 5–20, AGU, Washington, D.C., USA, 1994.
Aagaard, K., Coachman, L. K., and Carmack, E.: On the halocline of the Arctic
Ocean, Deep-Sea Res. Pt. A, 28, 529–545,
https://doi.org/10.1016/0198-0149(81)90115-1, 1981.
Bacle, J., Carmack, E. C., and Ingram, R. G.: Water column structure and
circulation under the North Water during spring transition: April–July
1998, Deep Sea Res. Part II Top. Stud. Oceanogr., 49(22–23), 4907–4925,
https://doi.org/10.1016/S0967-0645(02)00170-4, 2002.
Bauch, D., Schlosser, P., and Fairbanks, R. G.: Freshwater balance and the
sources of deep and bottom waters in the Arctic Ocean inferred from the
distribution of H218O, Prog. Oceanogr., 35, 53–80,
https://doi.org/10.1016/0079-6611(95)00005-2, 1995.
Broecker, W. S., Li, Y. H., and Cromwell, J.: Radium-226 and radon-222:
Concentration in Atlantic and Pacific Oceans, Science, 158,
1307–1310, https://doi.org/10.1126/science.158.3806.1307, 1967.
Burt, W. J., Thomas, H., Hagens, M., Patsch, J., Clargo, N. M., Salt, L. A.,
Winde, V., and Bottcher, M. E.: Carbon sources in the North Sea evaluated by
means of radium and stable carbon isotope tracers, Limnol. Oceanogr., 61,
666–683, https://doi.org/10.1002/lno.10243, 2016a.
Burt, W. J., Thomas, H., Miller, L. A., Granskog, M. A., Papakyriakou, T. N., and Pengelly, L.: Inorganic carbon cycling and biogeochemical processes in an Arctic inland sea (Hudson Bay), Biogeosciences, 13, 4659–4671, https://doi.org/10.5194/bg-13-4659-2016, 2016b.
Charette, M. A., Buesseler, K. O., and Andrews, J. E.: Utility of radium
isotopes for evaluating the input and transport of groundwater-derived
nitrogen to a Cape Cod estuary, Limnol. Oceanogr., 46, 465–470,
https://doi.org/10.4319/lo.2001.46.2.0465, 2001.
Charette, M. A., Morris, P. J., Henderson, P. B., and Moore, W. S.: Radium
isotope distributions during the US GEOTRACES North Atlantic cruises, Mar.
Chem., 177, 184–195, https://doi.org/10.1016/j.marchem.2015.01.001, 2015.
Charette, M. A., Lam, P. J., Lohan, M. C., Kwon, E. Y., Hatje, V., Jeandel,
C., Shiller, A. M., Cutter, G. A., Thomas, A., Boyd, P. W., Homoky, W. B.,
Milne, A., Thomas, H., Andersson, P. S., Porcelli, D., Tanaka, T., Geibert,
W., Dehairs, F., and Garcia-Orellana, J.: Coastal ocean and shelf-sea
biogeochemical cycling of trace elements and isotopes: lessons learned from
GEOTRACES, Philos. T. Roy. Soc. A, 374,
20160076, https://doi.org/10.1098/rsta.2016.0076, 2016.
Chung, Y.: Radium-barium-silica correlations and a two-dimensional radium
model for the world ocean, Earth Planet. Sc. Lett., 49, 309–318,
https://doi.org/10.1016/0012-821X(80)90074-6, 1980.
Coachman, L. K. and Aagaard, K.: Physical Oceanography of Arctic and
Subarctic Seas, in Marine Geology and Oceanography of the Arctic Seas, Springer Berlin Heidelberg, Berlin, Heidelberg, Germany,
1–72, 1974.
Coachman, L. K. and Barnes, C. A.: the Movement of Atlantic Water in the
Arctic Ocean, Arctic, 16, 1–80, https://doi.org/10.14430/arctic3517, 1963.
Cooper, L. W., Benner, R., Mcclelland, J. W., Peterson, B. J., Holmes, R.
M., Raymond, P. A., Hansell, D. A., Grebmeier, J. M., Codispoti, L. A.,
Cooper, L. W., Benner, R., Mcclelland, J. W., Peterson, B. J., Holmes, R.
M., Raymond, P. A., Hansell, D. A., Grebmeier, J. M., and Codispoti, L. A.:
Linkages among runoff, dissolved organic carbon, and the stable oxygen
isotope composition of seawater and other water mass indicators in the
Arctic Ocean, J. Geophys. Res., 110, 2013, https://doi.org/10.1029/2005JG000031, 2005.
Curry, B., Lee, C. M., and Petrie, B.: Volume, Freshwater, and Heat Fluxes
through Davis Strait, 2004-05*, J. Phys. Oceanogr., 11, 429–436,
https://doi.org/10.1175/2010JPO4536.1, 2011.
De Geer, L. E.: Currie detection limits in gamma-ray spectroscopy,
Appl. Radiat. Isotopes, 61, 151–160, 2004.
Eicken, H., Krouse, H. R., Kadko, D., and Perovich, D. K.: Tracer studies of
pathways and rates of meltwater transport through Arctic summer sea ice, J.
Geophys. Res.-Oceans, 107, SHE 22-1–SHE 22-20, https://doi.org/10.1029/2000jc000583, 2002.
Epstein, S. and Mayeda, T.: Variation of O18 content of waters from natural
sources, Geochim. Cosmochim. Ac., 4, 213–224,
https://doi.org/10.1016/0016-7037(53)90051-9, 1953.
Friis, K., Kortzinger, A., and Wallace, D. W. R.: The salinity normalization
of marine inorganic carbon chemistry data, Geophys. Res. Lett., 30, 1–4,
https://doi.org/10.1029/2002GL015898, 2003.
Gonneea, M. E., Mulligan, A. E., and Charette, M. A.: Seasonal cycles in
radium and barium within a subterranean estuary: Implications for
groundwater derived chemical fluxes to surface waters, Geochim. Cosmochim.
Ac., 119, 164–177, https://doi.org/10.1016/j.gca.2013.05.034, 2013.
Guay, C. K. and Falkner, K. K.: Barium as a tracer of Arctic halocline and
river waters, Deep-Sea Res. Pt. II,
44, 1543–1559., 1997.
Guay, C. K. and Falkner, K.: A survey of dissolved barium in the estuaries
of major Arctic rivers and adjacent seas, Cont. Shelf Res., 18, 859–882,
1998.
Guay, C. K. H., Mclaughlin, F. A., and Yamamoto-Kawai, M.: Differentiating
fluvial components of upper Canada Basin waters on the basis of measurements
of dissolved barium combined with other physical and chemical tracers, J.
Geophys. Res., 114, C00A09, https://doi.org/10.1029/2008JC005099, 2009.
Gunasekaran, R. and Kasirajan, T.: Principal Component Analysis (PCA) for
Beginners, Int. J. Adv. Sci. Res. Manag., 2, 9–11, 2017.
Hamilton, J. and Wu, Y.: Synopsis and trends in the physical environment of
Baffin Bay and Davis Strait, Can. Tech. Rep. Hydrogr. Ocean Sci., 282,
1–39, 2013.
Hamilton, J., Collins, K., and Prinsenberg, S. J.: Links between ocean
properties, ice cover, and plankton dynamics on interannual time scales in
the Canadian Arctic Archipelago, J. Geophys. Res.-Oceans, 118,
5625–5639, https://doi.org/10.1002/jgrc.20382, 2013.
Holland, M. M., Bitz, C. M., Eby, M., and Weaver, A. J.: The role of
ice-ocean interactions in the variability of the North Atlantic thermohaline
circulation, J. Climate, 14, 656–675,
https://doi.org/10.1175/1520-0442(2001)014<0656:TROIOI>2.0.CO;2,
2001.
Hoppema, M., Dehairs, F., Navez, J., Monnin, C., Jeandel, C., Fahrbach, E., and de Baar, H. J. W.: Distribution of barium in the Weddell Gyre: Impact of
circulation and biogeochemical processes, Mar. Chem., 122, 118–129,
https://doi.org/10.1016/j.marchem.2010.07.005, 2010.
Ingram, R. G. and Prinsenberg, S. J.: Coastal oceanography of Hudson Bay and
surrounding eastern Canadian Arctic Waters Coastal Segment (26P), in: The
Sea, edited by: Robinson, A. R. and Brink, K. H., Wiley,
New York, USA, vol. 11, 835–861, 1998.
International Atomic Energy Agency (IAEA): Inventories of Selected
Radionoclides in the Oceans, Vienna, Austria, 1988.
International Atomic Energy Agency (IAEA): Analytical Methodology for the
Determination of Radium Isotopes in Environmental Samples (IAEA/AQ–19),
Seiberdorf, Austria, 2010.
Jackson, J. E.: Scaling of Data, in: A Use's Guide to Principal Components, edited by: Jackson, J. E., https://doi.org/10.1002/0471725331.ch3,
2004.
Jakobsson, M.: Hypsometry and volume of the Arctic Ocean and its constituent
seas, Geochem. Geophy. Geosy., 3, 1–18,
https://doi.org/10.1029/2001GC000302, 2002.
Jolliffe, I. T. and Cadima, J.: Principal component analysis: a review and
recent developments, Philos. Trans. A. Math. Phys. Eng. Sci., 374,
20150202, https://doi.org/10.1098/rsta.2015.0202, 2016.
Jones, E. P.: Tracing Pacific water in the North Atlantic Ocean, J. Geophys.
Res., 108, 3116, https://doi.org/10.1029/2001JC001141, 2003.
Kadko, D. and Muench, R.: Evaluation of shelf-basin interaction in the
western Arctic by use of short-lived radium isotopes: The importance of
mesoscale processes, Deep-Sea Res. Pt. II, 52,
3227–3244, https://doi.org/10.1016/j.dsr2.2005.10.008, 2005.
Kawakami, H. and Kusakabe, M.: Surface water mixing estimated from 228Ra and
226Ra in the northwestern North Pacific, J. Environ. Radioact., 99,
1335–1340, https://doi.org/10.1016/j.jenvrad.2008.04.011, 2008.
Kipp, L. E., Charette, M. A., Moore, W. S., Henderson, P. B., and Rigor, I.
G.: Increased fluxes of shelf-derived materials to the central Arctic Ocean,
Sci. Adv., 4, 1–9, https://doi.org/10.1126/sciadv.aao1302, 2018.
Kipp, L. E., Kadko, D. C., Pickart, R. S., Henderson, P. B., Moore, W. S., and Charette, M. A.: Shelf-Basin Interactions and Water Mass Residence Times
in the Western Arctic Ocean: Insights Provided by Radium Isotopes, J.
Geophys. Res.-Oceans, 124, 3279–3297, https://doi.org/10.1029/2019JC014988, 2019.
Lansard, B., Mucci, A., Miller, L. A., Macdonald, R. W., and Gratton, Y.:
Seasonal variability of water mass distribution in the southeastern Beaufort
Sea determined by total alkalinity and δ18O, J. Geophys. Res.-Oceans, 117, C03003, https://doi.org/10.1029/2011JC007299, 2012.
Le Roy, E., Sanial, V., Charette, M. A., van Beek, P., Lacan, F., Jacquet, S. H. M., Henderson, P. B., Souhaut, M., García-Ibáñez, M. I., Jeandel, C., Pérez, F. F., and Sarthou, G.: The 226Ra–Ba relationship in the North Atlantic during GEOTRACES-GA01, Biogeosciences, 15, 3027–3048, https://doi.org/10.5194/bg-15-3027-2018, 2018.
Lobb, J., Carmack, E. C., Ingram, R. G., and Weaver, A. J.: Structure and
mixing across an Arctic/Atlantic front in northern Baffin Bay, Geophys. Res.
Lett., 30, 1833, https://doi.org/10.1029/2003GL017755, 2003.
Macdonald, R. W., Wong, C. S., and Erickson, P. E.: The distribution of
nutrients in the southeastern Beaufort Sea: Implications for water
circulation and primary production, J. Geophys. Res., 92, 2939,
https://doi.org/10.1029/JC092iC03p02939, 1987.
Macdonald, R. W., Carmack, E. C., McLaughlin, F. A., Iseki, K., Macdonald,
D. M., and O'Brien, M. C.: Composition and modification of water masses in
the Mackenzie shelf estuary, J. Geophys. Res., 94, 18057,
https://doi.org/10.1029/JC094iC12p18057, 1989.
Macdonald, R. W., Carmack, E. C., Mclaughlin, F. A., Falkner, K. K., and
Swift, J. H.: Connections among ice, runoff and atmospheric forcing in the
Beaufort Gyre, Geophys. Res. Lett., 26, 2223–2226,
https://doi.org/10.1029/1999GL900508, 1999.
Mathis, J. T., Hansell, D. A., and Bates, N. R.: Strong hydrographic controls
on spatial and seasonal variability of dissolved organic carbon in the
Chukchi Sea, Deep-Sea Res. Pt. II, 52,
3245–3258, https://doi.org/10.1016/J.DSR2.2005.10.002, 2005.
Monnin, C.: A thermodynamic model for the solubility of barite and celestite
in electrolyte solutions and seawater to 200 ∘C and to 1 kbar, Chem. Geol.,
153, 187–209, https://doi.org/10.1016/S0009-2541(98)00171-5, 1999.
Moore, W. S.: Determining coastal mixing rates using radium isotopes, Cont.
Shelf Res., 20, 1993–2007, https://doi.org/10.1016/S0278-4343(00)00054-6, 2000.
Moore, W. S.: Seasonal distribution and flux of radium isotopes on the
southeastern U.S. continental shelf, J. Geophys. Res., 112, C10013, https://doi.org/10.1029/2007JC004199, 2007.
Moore, W. S.: Fifteen years experience in measuring 224Ra and 223Ra by
delayed-coincidence counting, Mar. Chem., 109, 188–197,
https://doi.org/10.1016/j.marchem.2007.06.015, 2008.
Moore, W. S. and Arnold, R.: Measurement of 223 Ra and 224 Ra in coastal
waters using a delayed coincidence counter, J. Geophys. Res.-Oceans,
101, 1321–1329, https://doi.org/10.1029/95JC03139, 1996.
Moore, W. S. and Dymond, J.: Fluxes of 226Ra and barium in the Pacific
Ocean: The importance of boundary processes, Earth Planet. Sc. Lett.,
107, 55–68, https://doi.org/10.1016/0012-821X(91)90043-H, 1991.
Moore, W. S. and Reid, D. F.: Extraction of Radium from Natural Waters Using
Manganese-Impregnated Acrylic Fibers, J. Geophys. Res., 78, 8880–8886,
https://doi.org/10.1029/JC078i036p08880, 1973.
Moore, W. S., Feely, H. W., and Li, Y.-H.: Radium isotopes in sub-Arctic
waters, Earth Planet. Sc. Lett., 49, 329–340,
https://doi.org/10.1016/0012-821X(80)90076-X, 1980.
Moore, W. S., Sarmiento, J. L., and Key, R. M.: Submarine groundwater
discharge revealed by 228Ra distribution in the upper Atlantic Ocean, Nat. Geosci., 1, 309–311,
https://doi.org/10.1038/ngeo183, 2008.
Mucci, A., Levasseur, M., Gratton, Y., Martias, C., Scarratt, M., Gilbert,
D., Tremblay, J.-E., Ferreyra, G., and Lansard, B.: Tidally induced
variations of pH at the head of the Laurentian Channel, Can. J. Fish. Aquat.
Sci., 75, 1128–1141, https://doi.org/10.1139/cjfas-2017-0007, 2018.
Newton, J. L. and Coachman, L. K.: Atlantic Water Circulation in the Canada
Basin, Arctic, 27, 297–303, https://doi.org/10.14430/arctic2886, 1974.
Pearson, K.: On lines and planes of closet fit to systems of points in
space, J. Sci., 2, 559–572, https://doi.org/10.1080/14786440109462720, 1901.
Peres-Neto, P. R., Jackson, D. A., and Somers, K. M.: Giving meaningful
interpritation to ordination axes: Assesing loading significance in
principal components analysis, Ecology, 84, 2347–2363,
https://doi.org/10.1890/00-0634, 2003.
Peterson, I., Hamilton, J., Prinsenberg, S., and Pettipas, R.: Wind-forcing
of volume transport through Lancaster Sound, J. Geophys. Res.-Oceans,
117, C11018, https://doi.org/10.1029/2012JC008140, 2012.
Prinsenberg, S. J.: Volume, Heat and freshwater flxes through the Canadian
Arctic Archipelago: Present Understanding and Future Research Plans, report,
Bedford Institute of Oceanography, Fisheries and Oceans Canada, Dartmouth, NS, Canada, 1982.
Prinsenberg, S. J. and Bennett, E. B.: Mixing and transports in Barrow
Strait, the central part of the Northwest Passage, Cont. Shelf Res., 7,
913–935, https://doi.org/10.1016/0278-4343(87)90006-9, 1987.
Prinsenberg, S. J., Hamilton, J., Peterson, I., and Pettipas, R.: Observing and interpreting the seasonal variability of the oceanographic fluxes passing through Lancaster Sound of the Canadian Arctic Archipelago, in: Influence of Climate Change on the Changing Arctic and Sub-Arctic Conditions, edited by: Nihoul, J. C. J. and Kostianoy, A. G., NATO Science for Peace and Security Series C: Environmental Security, Springer, Dordrecht, https://doi.org/10.1007/978-1-4020-9460-6_10, 2009.
Rahmstorf, S.: Ocean circulation and climate during the past 120,000 years,
Nature, 419, 207–214, https://doi.org/10.1038/nature01090, 2002.
Rudels, B.: The outflow of polar water through the Arctic Archipelago and
the oceanographic conditions in Baffin Bay, Polar Res., 4, 161–180,
https://doi.org/10.3402/polar.v4i2.6929, 1986.
Rutgers Van Der Loeff, M. M., Key, R. M., Scholten, J., Bauch, D., and
Michel, A.: 228Ra as a tracer for shelf water in the arctic ocean, Deep-Sea
Res. Pt. II, 42, 1533–1553, https://doi.org/10.1016/0967-0645(95)00053-4, 1995.
Rutgers Van Der Loeff, M. and Moore, W. S.: Determination of natural radioactive tracers, in: Methods of Seawater Analysis, edited by: Grasshoff, K., Kremling, K., and Ehrhardt, M., https://doi.org/10.1002/9783527613984.ch13, 2007.
Rutgers Van Der Loeff, M., Kuhne, S., Wahsner, M., Holtzen, H., Frank, M.,
Ekwurzel, B., Mensch, M., and Rachold, V.: 228Ra and 226Ra in the Kara and
Laptev seas, Cont. Shelf Res., 23, 113–124,
https://doi.org/10.1016/S0278-4343(02)00169-3, 2003.
Shadwick, E. H., Thomas, H., Gratton, Y., Leong, D., Moore, S. A.,
Papakyriakou, T., and Prowe, A. E. F.: Export of Pacific carbon through the
Arctic Archipelago to the North Atlantic, Cont. Shelf Res., 31, 806–816,
https://doi.org/10.1016/j.csr.2011.01.014, 2011a.
Shadwick, E. H., Thomas, H., Chierici, M., Else, B., Fransson, A., Michel,
C., Miller, L. A., Mucci, A., Niemi, A., Papakyriakou, T. N., and Tremblay,
J.-E.: Seasonal variability of the inorganic carbon system in the Amundsen
Gulf region of the southeastern Beaufort Sea, Limnol. Oceanogr., 56,
303–322, https://doi.org/10.4319/lo.2011.56.1.0303, 2011b.
Shadwick, E. H., Trull, T. W., Thomas, H., and Gibson, J. A. E.:
Vulnerability of Polar Oceans to Anthropogenic Acidification: Comparison of
Arctic and Antarctic Seasonal Cycles, Sci. Rep., 3, 2339,
https://doi.org/10.1038/srep02339, 2013.
Smith, J., Moran, S., and Macdonald, R.: Shelf–basin interactions in
the Arctic Ocean based on 210Pb and Ra isotope tracer distributions, Deep-Sea Res. Pt. I, 50, 397–416,
https://doi.org/10.1016/S0967-0637(02)00166-8, 2003.
Thomas, H., Shadwick, E., Dehairs, F., Lansard, B., Mucci, A., Navez, J.,
Gratton, Y., Prowe, F., Chierici, M., Fransson, A., Papakyriakou, T. N.,
Sternberg, E., Miller, L. A., Tremblay, J. E., and Monnin, C.: Barium and
carbon fluxes in the Canadian Arctic Archipelago, J. Geophys. Res., 116,
1–16, https://doi.org/10.1029/2011JC007120, 2011.
van Beek, P., Bourquin, M., Reyss, J.-L., Souhaut, M., Charette, M. A., and
Jeandel, C.: Radium isotopes to investigate the water mass pathways on the
Kerguelen Plateau (Southern Ocean), Deep-Sea Res. Pt. II, 55, 622–637, https://doi.org/10.1016/J.DSR2.2007.12.025, 2007.
Walsh, J. J.: Importance of continental margins in the marine biogeochemical
cycling of carbon and nitrogen, Nature, 350, 53–55,
https://doi.org/10.1038/350053a0, 1991.
Wang, Q., Myers, P. G., Hu, X., and Bush, A. B. G.: Flow Constraints on
Pathways through the Canadian Arctic Archipelago, Atmos.-Ocean, 50, 373–385,
https://doi.org/10.1080/07055900.2012.704348, 2012.
Xing, N., Chen, M., Huang, Y., Cai, P., and Qiu, Y.: Distribution of 226Ra in
the Arctic Ocean and the Bering Sea and its hydrologic implications, Sci.
China Ser. D, 46, 516–528, https://doi.org/10.1360/03yd9045, 2003.
Yamamoto-Kawai, M., Mclaughlin, F. A., Carmack, E. C., Nishino, S., Shimada,
K., and Kurita, N.: Surface freshening of the Canada Basin, J. Geophys. Res.,
114, C00A05, https://doi.org/10.1029/2008JC005000, 2009.
Yamamoto-Kawai, M., Carmack, E. C., McLaughlin, F. A., and Falkner, K. K.:
Oxygen isotope ratio, barium and salinity in waters around the North
American coast from the Pacific to the Atlantic: Implications for freshwater
sources to the Arctic throughflow, J. Mar. Res., 68, 97–117,
https://doi.org/10.1357/002224010793078988, 2010.
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Major research initiatives have been undertaken within the Arctic Ocean, highlighting this area's global importance and vulnerability to climate change. In 2015, the international GEOTRACES program addressed this importance by devoting intense research activities to the Arctic Ocean. Among various tracers, we used radium and carbonate system data to elucidate the functioning and vulnerability of the hydrographic regime of the Canadian Arctic Archipelago, bridging the Pacific and Atlantic oceans.
Major research initiatives have been undertaken within the Arctic Ocean, highlighting this...
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