Articles | Volume 17, issue 5
https://doi.org/10.5194/bg-17-1327-2020
© 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-17-1327-2020
© 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 Mar 2020
Research article |
| 16 Mar 2020
| 16 Mar 2020
Fe(II) stability in coastal seawater during experiments in Patagonia, Svalbard, and Gran Canaria
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Carolina Santana-González
Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las
Palmas de Gran Canaria, ULPGC, Las Palmas, Spain
Julian Gallego-Urrea
Department of Marine Sciences, Kristineberg Marine Research Station, University of Gothenburg, Gothenburg, Sweden
Nicolas Sanchez
Norwegian University of Science and Technology, Trondheim, Trondheim, Norway
Eric P. Achterberg
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Murat V. Ardelan
Norwegian University of Science and Technology, Trondheim, Trondheim, Norway
Martha Gledhill
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Melchor González-Dávila
Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las
Palmas de Gran Canaria, ULPGC, Las Palmas, Spain
Linn Hoffmann
Department of Chemistry, University of Otago, Dunedin, New Zealand
Øystein Leiknes
Norwegian University of Science and Technology, Trondheim, Trondheim, Norway
Juana Magdalena Santana-Casiano
Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las
Palmas de Gran Canaria, ULPGC, Las Palmas, Spain
Tatiana M. Tsagaraki
Department of Biological Sciences, University of Bergen, Bergen, Norway
David Turner
Department of Marine Sciences, University of Gothenburg, Gothenburg, Sweden
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Elise S. Droste, Mario Hoppema, Melchor González-Dávila, Juana Magdalena Santana-Casiano, Bastien Y. Queste, Giorgio Dall'Olmo, Hugh J. Venables, Gerd Rohardt, Sharyn Ossebaar, Daniel Schuller, Sunke Trace-Kleeberg, and Dorothee C. E. Bakker
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Shao-Min Chen, Ulf Riebesell, Kai G. Schulz, Elisabeth von der Esch, Eric P. Achterberg, and Lennart T. Bach
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Loes J. A. Gerringa, Martha Gledhill, Indah Ardiningsih, Niels Muntjewerf, and Luis M. Laglera
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Neil J. Wyatt, Angela Milne, Eric P. Achterberg, Thomas J. Browning, Heather A. Bouman, E. Malcolm S. Woodward, and Maeve C. Lohan
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Maximiliano J. Vergara-Jara, Mark J. Hopwood, Thomas J. Browning, Insa Rapp, Rodrigo Torres, Brian Reid, Eric P. Achterberg, and José Luis Iriarte
Ocean Sci., 17, 561–578, https://doi.org/10.5194/os-17-561-2021, https://doi.org/10.5194/os-17-561-2021, 2021
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Preprint withdrawn
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Yu-Te Hsieh, Walter Geibert, E. Malcolm S. Woodward, Neil J. Wyatt, Maeve C. Lohan, Eric P. Achterberg, and Gideon M. Henderson
Biogeosciences, 18, 1645–1671, https://doi.org/10.5194/bg-18-1645-2021, https://doi.org/10.5194/bg-18-1645-2021, 2021
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Jan Lüdke, Marcus Dengler, Stefan Sommer, David Clemens, Sören Thomsen, Gerd Krahmann, Andrew W. Dale, Eric P. Achterberg, and Martin Visbeck
Ocean Sci., 16, 1347–1366, https://doi.org/10.5194/os-16-1347-2020, https://doi.org/10.5194/os-16-1347-2020, 2020
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We analyse the intraseasonal variability of the alongshore circulation off Peru in early 2017, this circulation is very important for the supply of nutrients to the upwelling regime. The causes of this variability and its impact on the biogeochemistry are investigated. The poleward flow is strengthened during the observed time period, likely by a downwelling coastal trapped wave. The stronger current causes an increase in nitrate and reduces the deficit of fixed nitrogen relative to phosphorus.
Ruifang C. Xie, Frédéric A. C. Le Moigne, Insa Rapp, Jan Lüdke, Beat Gasser, Marcus Dengler, Volker Liebetrau, and Eric P. Achterberg
Biogeosciences, 17, 4919–4936, https://doi.org/10.5194/bg-17-4919-2020, https://doi.org/10.5194/bg-17-4919-2020, 2020
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Thorium-234 (234Th) is widely used to study carbon fluxes from the surface ocean to depth. But few studies stress the relevance of oceanic advection and diffusion on the downward 234Th fluxes in nearshore environments. Our study in offshore Peru showed strong temporal variations in both the importance of physical processes on 234Th flux estimates and the oceanic residence time of 234Th, whereas salinity-derived seawater 238U activities accounted for up to 40 % errors in 234Th flux estimates.
Lennart Thomas Bach, Allanah Joy Paul, Tim Boxhammer, Elisabeth von der Esch, Michelle Graco, Kai Georg Schulz, Eric Achterberg, Paulina Aguayo, Javier Arístegui, Patrizia Ayón, Isabel Baños, Avy Bernales, Anne Sophie Boegeholz, Francisco Chavez, Gabriela Chavez, Shao-Min Chen, Kristin Doering, Alba Filella, Martin Fischer, Patricia Grasse, Mathias Haunost, Jan Hennke, Nauzet Hernández-Hernández, Mark Hopwood, Maricarmen Igarza, Verena Kalter, Leila Kittu, Peter Kohnert, Jesus Ledesma, Christian Lieberum, Silke Lischka, Carolin Löscher, Andrea Ludwig, Ursula Mendoza, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Joaquin Ortiz Cortes, Jonna Piiparinen, Claudia Sforna, Kristian Spilling, Sonia Sanchez, Carsten Spisla, Michael Sswat, Mabel Zavala Moreira, and Ulf Riebesell
Biogeosciences, 17, 4831–4852, https://doi.org/10.5194/bg-17-4831-2020, https://doi.org/10.5194/bg-17-4831-2020, 2020
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The eastern boundary upwelling system off Peru is among Earth's most productive ocean ecosystems, but the factors that control its functioning are poorly constrained. Here we used mesocosms, moored ~ 6 km offshore Peru, to investigate how processes in plankton communities drive key biogeochemical processes. We show that nutrient and light co-limitation keep productivity and export at a remarkably constant level while stoichiometry changes strongly with shifts in plankton community structure.
Daniel Broullón, Fiz F. Pérez, Antón Velo, Mario Hoppema, Are Olsen, Taro Takahashi, Robert M. Key, Toste Tanhua, J. Magdalena Santana-Casiano, and Alex Kozyr
Earth Syst. Sci. Data, 12, 1725–1743, https://doi.org/10.5194/essd-12-1725-2020, https://doi.org/10.5194/essd-12-1725-2020, 2020
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Anna Plass, Christian Schlosser, Stefan Sommer, Andrew W. Dale, Eric P. Achterberg, and Florian Scholz
Biogeosciences, 17, 3685–3704, https://doi.org/10.5194/bg-17-3685-2020, https://doi.org/10.5194/bg-17-3685-2020, 2020
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We compare the cycling of Fe and Cd in sulfidic sediments of the Peruvian oxygen minimum zone. Due to the contrasting solubility of their sulfide minerals, the sedimentary Fe release and Cd burial fluxes covary with spatial and temporal distributions of H2S. Depending on the solubility of their sulfide minerals, sedimentary trace metal fluxes will respond differently to ocean deoxygenation/expansion of H2S concentrations, which may change trace metal stoichiometry of upwelling water masses.
Katharina Seelmann, Martha Gledhill, Steffen Aßmann, and Arne Körtzinger
Ocean Sci., 16, 535–544, https://doi.org/10.5194/os-16-535-2020, https://doi.org/10.5194/os-16-535-2020, 2020
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We investigated the impact of indicator dye impurities on spectrophotometric seawater measurements, especially how they may influence the drift behavior and the measurement quality of an autonomous analyzer using this indicator. These measurements are important for ocean carbon observations. This work revealed that impurities up to a quantity of 2 % do not influence the measurement drift and quality. Higher impurity levels lead to a changing drift behavior and quality deteriorations.
Mark J. Hopwood, Dustin Carroll, Thorben Dunse, Andy Hodson, Johnna M. Holding, José L. Iriarte, Sofia Ribeiro, Eric P. Achterberg, Carolina Cantoni, Daniel F. Carlson, Melissa Chierici, Jennifer S. Clarke, Stefano Cozzi, Agneta Fransson, Thomas Juul-Pedersen, Mie H. S. Winding, and Lorenz Meire
The Cryosphere, 14, 1347–1383, https://doi.org/10.5194/tc-14-1347-2020, https://doi.org/10.5194/tc-14-1347-2020, 2020
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Here we compare and contrast results from five well-studied Arctic field sites in order to understand how glaciers affect marine biogeochemistry and marine primary production. The key questions are listed as follows. Where and when does glacial freshwater discharge promote or reduce marine primary production? How does spatio-temporal variability in glacial discharge affect marine primary production? And how far-reaching are the effects of glacial discharge on marine biogeochemistry?
Claudia Frey, Hermann W. Bange, Eric P. Achterberg, Amal Jayakumar, Carolin R. Löscher, Damian L. Arévalo-Martínez, Elizabeth León-Palmero, Mingshuang Sun, Xin Sun, Ruifang C. Xie, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 17, 2263–2287, https://doi.org/10.5194/bg-17-2263-2020, https://doi.org/10.5194/bg-17-2263-2020, 2020
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The production of N2O via nitrification and denitrification associated with low-O2 waters is a major source of oceanic N2O. We investigated the regulation and dynamics of these processes with respect to O2 and organic matter inputs. The transcription of the key nitrification gene amoA rapidly responded to changes in O2 and strongly correlated with N2O production rates. N2O production by denitrification was clearly stimulated by organic carbon, implying that its supply controls N2O production.
Mark J. Hopwood, Nicolas Sanchez, Despo Polyviou, Øystein Leiknes, Julián Alberto Gallego-Urrea, Eric P. Achterberg, Murat V. Ardelan, Javier Aristegui, Lennart Bach, Sengul Besiktepe, Yohann Heriot, Ioanna Kalantzi, Tuba Terbıyık Kurt, Ioulia Santi, Tatiana M. Tsagaraki, and David Turner
Biogeosciences, 17, 1309–1326, https://doi.org/10.5194/bg-17-1309-2020, https://doi.org/10.5194/bg-17-1309-2020, 2020
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Hydrogen peroxide, H2O2, is formed naturally in sunlight-exposed water by photochemistry. At high concentrations it is undesirable to biological cells because it is a stressor. Here, across a range of incubation experiments in diverse marine environments (Gran Canaria, the Mediterranean, Patagonia and Svalbard), we determine that two factors consistently affect the H2O2 concentrations irrespective of geographical location: bacteria abundance and experiment design.
Insa Rapp, Christian Schlosser, Jan-Lukas Menzel Barraqueta, Bernhard Wenzel, Jan Lüdke, Jan Scholten, Beat Gasser, Patrick Reichert, Martha Gledhill, Marcus Dengler, and Eric P. Achterberg
Biogeosciences, 16, 4157–4182, https://doi.org/10.5194/bg-16-4157-2019, https://doi.org/10.5194/bg-16-4157-2019, 2019
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The availability of iron (Fe) affects phytoplankton growth in large parts of the ocean. Shelf sediments, particularly in oxygen minimum zones, are a major source of Fe and other essential micronutrients, such as cobalt (Co) and manganese (Mn). We observed enhanced concentrations of Fe, Co, and Mn corresponding with low oxygen concentrations along the Mauritanian shelf, indicating that the projected future decrease in oxygen concentrations may result in increases in Fe, Mn, and Co concentrations.
Daniel Broullón, Fiz F. Pérez, Antón Velo, Mario Hoppema, Are Olsen, Taro Takahashi, Robert M. Key, Toste Tanhua, Melchor González-Dávila, Emil Jeansson, Alex Kozyr, and Steven M. A. C. van Heuven
Earth Syst. Sci. Data, 11, 1109–1127, https://doi.org/10.5194/essd-11-1109-2019, https://doi.org/10.5194/essd-11-1109-2019, 2019
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In this work, we are contributing to the knowledge of the consequences of climate change in the ocean. We have focused on a variable related to this process: total alkalinity. We have designed a monthly climatology of total alkalinity using artificial intelligence techniques, that is, a representation of the average capacity of the ocean in the last decades to decelerate the consequences of climate change. The climatology is especially useful to infer the evolution of the ocean through models.
Jan-Lukas Menzel Barraqueta, Jessica K. Klar, Martha Gledhill, Christian Schlosser, Rachel Shelley, Hélène F. Planquette, Bernhard Wenzel, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 16, 1525–1542, https://doi.org/10.5194/bg-16-1525-2019, https://doi.org/10.5194/bg-16-1525-2019, 2019
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We used surface water dissolved aluminium concentrations collected in four different GEOTRACES cruises to determine atmospheric deposition fluxes to the ocean. We calculate atmospheric deposition fluxes for largely under-sampled regions of the Atlantic Ocean and thus provide new constraints for models of atmospheric deposition. The use of the MADCOW model is of major importance as dissolved aluminium is analysed within the GEOTRACES project at high spatial resolution.
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.
Jan-Lukas Menzel Barraqueta, Christian Schlosser, Hélène Planquette, Arthur Gourain, Marie Cheize, Julia Boutorh, Rachel Shelley, Leonardo Contreira Pereira, Martha Gledhill, Mark J. Hopwood, François Lacan, Pascale Lherminier, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 15, 5271–5286, https://doi.org/10.5194/bg-15-5271-2018, https://doi.org/10.5194/bg-15-5271-2018, 2018
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In the North Atlantic and Labrador Sea, low aerosol deposition and enhanced primary productivity control the dissolved aluminium (dAl) surface distribution, while remineralization of particles seems to control the distribution at depth. DAl in the ocean allows us to indirectly quantify the amount of dust deposited to a given region for a given period. Hence, the study of its distribution, cycling, sources, and sinks is of major importance to improve aerosol deposition models and climate models.
Christian Schlosser, Katrin Schmidt, Alfred Aquilina, William B. Homoky, Maxi Castrillejo, Rachel A. Mills, Matthew D. Patey, Sophie Fielding, Angus Atkinson, and Eric P. Achterberg
Biogeosciences, 15, 4973–4993, https://doi.org/10.5194/bg-15-4973-2018, https://doi.org/10.5194/bg-15-4973-2018, 2018
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Iron (Fe) emanating from the South Georgia shelf system fuels large phytoplankton blooms downstream of the island. However, the actual supply mechanisms of Fe are unclear. We found that shelf-sediment-derived iron and iron released from Antarctic krill control the Fe distribution in the shelf waters around South Georgia. The majority of the Fe appears to be derived from recycling of Fe-enriched particles that are transported with the water masses into the bloom region.
Melchor González-Dávila, J. Magdalena Santana Casiano, and Francisco Machín
Biogeosciences, 14, 3859–3871, https://doi.org/10.5194/bg-14-3859-2017, https://doi.org/10.5194/bg-14-3859-2017, 2017
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The Mauritanian–Cap Vert upwelling is shown to be sensitive to climate change forcing on upwelling processes, which strongly affects the CO2 surface distribution, ocean acidification rates, and air–sea CO2 exchange. We confirmed an upwelling intensification, an increase in the CO2 outgassing, and an important decrease in the pH of the surface waters. Upwelling areas are poorly studied and VOS lines are shown as one of the most significant contributors to our knowledge of the ocean's response.
Giulia Faucher, Linn Hoffmann, Lennart T. Bach, Cinzia Bottini, Elisabetta Erba, and Ulf Riebesell
Biogeosciences, 14, 3603–3613, https://doi.org/10.5194/bg-14-3603-2017, https://doi.org/10.5194/bg-14-3603-2017, 2017
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The main goal of this study was to understand if, similarly to the fossil record, high quantities of toxic metals induce coccolith dwarfism in coccolithophore species. We investigated, for the first time, the effects of trace metals on coccolithophore species other than E. huxleyi and on coccolith morphology and size. Our data show a species-specific sensitivity to trace metal concentration, allowing the recognition of the most-, intermediate- and least-tolerant taxa to trace metal enrichments.
Thomas Hornick, Lennart T. Bach, Katharine J. Crawfurd, Kristian Spilling, Eric P. Achterberg, Jason N. Woodhouse, Kai G. Schulz, Corina P. D. Brussaard, Ulf Riebesell, and Hans-Peter Grossart
Biogeosciences, 14, 1–15, https://doi.org/10.5194/bg-14-1-2017, https://doi.org/10.5194/bg-14-1-2017, 2017
Kristian Spilling, Kai G. Schulz, Allanah J. Paul, Tim Boxhammer, Eric P. Achterberg, Thomas Hornick, Silke Lischka, Annegret Stuhr, Rafael Bermúdez, Jan Czerny, Kate Crawfurd, Corina P. D. Brussaard, Hans-Peter Grossart, and Ulf Riebesell
Biogeosciences, 13, 6081–6093, https://doi.org/10.5194/bg-13-6081-2016, https://doi.org/10.5194/bg-13-6081-2016, 2016
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We performed an experiment in the Baltic Sea in order to investigate the consequences of the increasing CO2 levels on biological processes in the free water mass. There was more accumulation of organic carbon at high CO2 levels. Surprisingly, this was caused by reduced loss processes (respiration and bacterial production) in a high-CO2 environment, and not by increased photosynthetic fixation of CO2. Our carbon budget can be used to better disentangle the effects of ocean acidification.
Allanah J. Paul, Eric P. Achterberg, Lennart T. Bach, Tim Boxhammer, Jan Czerny, Mathias Haunost, Kai-Georg Schulz, Annegret Stuhr, and Ulf Riebesell
Biogeosciences, 13, 3901–3913, https://doi.org/10.5194/bg-13-3901-2016, https://doi.org/10.5194/bg-13-3901-2016, 2016
Matthew P. Humphreys, Florence M. Greatrix, Eithne Tynan, Eric P. Achterberg, Alex M. Griffiths, Claudia H. Fry, Rebecca Garley, Alison McDonald, and Adrian J. Boyce
Earth Syst. Sci. Data, 8, 221–233, https://doi.org/10.5194/essd-8-221-2016, https://doi.org/10.5194/essd-8-221-2016, 2016
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This paper reports the stable isotope composition of dissolved inorganic carbon in seawater for a transect from west to east across the North Atlantic Ocean. The results can be used to study oceanic uptake of anthropogenic carbon dioxide, and also to investigate the natural biological carbon pump. We also provide stable DIC isotope results for two batches of Dickson seawater CRMs to enable intercomparisons with other studies.
Monika Nausch, Lennart Thomas Bach, Jan Czerny, Josephine Goldstein, Hans-Peter Grossart, Dana Hellemann, Thomas Hornick, Eric Pieter Achterberg, Kai-Georg Schulz, and Ulf Riebesell
Biogeosciences, 13, 3035–3050, https://doi.org/10.5194/bg-13-3035-2016, https://doi.org/10.5194/bg-13-3035-2016, 2016
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Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. Therefore, we conducted a CO2-manipulation mesocosm experiment in the Storfjärden (western Gulf of Finland, Baltic Sea) in summer 2012. We compared the phosphorus dynamics in different mesocosm treatment
A. J. Paul, L. T. Bach, K.-G. Schulz, T. Boxhammer, J. Czerny, E. P. Achterberg, D. Hellemann, Y. Trense, M. Nausch, M. Sswat, and U. Riebesell
Biogeosciences, 12, 6181–6203, https://doi.org/10.5194/bg-12-6181-2015, https://doi.org/10.5194/bg-12-6181-2015, 2015
Y. Zhang, N. Mahowald, R. A. Scanza, E. Journet, K. Desboeufs, S. Albani, J. F. Kok, G. Zhuang, Y. Chen, D. D. Cohen, A. Paytan, M. D. Patey, E. P. Achterberg, J. P. Engelbrecht, and K. W. Fomba
Biogeosciences, 12, 5771–5792, https://doi.org/10.5194/bg-12-5771-2015, https://doi.org/10.5194/bg-12-5771-2015, 2015
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A new technique to determine a size-fractionated global soil elemental emission inventory based on a global soil and mineralogical data set is introduced. Spatial variability of mineral dust elemental fractions (8 elements, e.g., Ca, Fe, Al) is identified on a global scale, particularly for Ca. The Ca/Al ratio ranged between 0.1 and 5.0 and is confirmed as an indicator of dust source regions by a global dust model. Total and soluble dust element fluxes into different ocean basins are estimated.
I. Hernández-Carrasco, J. Sudre, V. Garçon, H. Yahia, C. Garbe, A. Paulmier, B. Dewitte, S. Illig, I. Dadou, M. González-Dávila, and J. M. Santana-Casiano
Biogeosciences, 12, 5229–5245, https://doi.org/10.5194/bg-12-5229-2015, https://doi.org/10.5194/bg-12-5229-2015, 2015
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We have reconstructed maps of air-sea CO2 fluxes at high resolution (4 km) in the offshore Benguela region using sea surface temperature and ocean colour data and CarbonTracker CO2 fluxes data at low resolution (110 km).
The inferred representation of pCO2 improves the description provided by CarbonTracker, enhancing small-scale variability.
We find that the resolution, as well as the inferred pCO2 data itself, is closer to in situ measurements of pCO2.
M. P. Humphreys, E. P. Achterberg, A. M. Griffiths, A. McDonald, and A. J. Boyce
Earth Syst. Sci. Data, 7, 127–135, https://doi.org/10.5194/essd-7-127-2015, https://doi.org/10.5194/essd-7-127-2015, 2015
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We present measurements of the stable carbon isotope composition of seawater dissolved inorganic carbon. The samples were collected during two research cruises in boreal summer 2012 in the northeastern Atlantic and Nordic Seas. The results can be used to investigate the marine carbon cycle, providing information about biological productivity and oceanic uptake of anthropogenic carbon dioxide.
N. Sanchez, M. V. Ardelan, N. Bizsel, and J. L. Iriarte
Biogeosciences Discuss., https://doi.org/10.5194/bgd-11-13739-2014, https://doi.org/10.5194/bgd-11-13739-2014, 2014
Revised manuscript not accepted
Related subject area
Biogeochemistry: Coastal Ocean
Ocean alkalinity enhancement (OAE) does not cause cellular stress in a phytoplankton community of the subtropical Atlantic Ocean
Reviews and syntheses: On increasing hypoxia in eastern boundary upwelling systems – zooplankton under metabolic stress
Technical note: Testing a new approach for the determination of N2 fixation rates by coupling a membrane equilibrator to a mass spectrometer for long-term observations
Long-term variations in pH in coastal waters along the Korean Peninsula
The effect of carbonate mineral additions on biogeochemical conditions in surface sediments and benthic–pelagic exchange fluxes
Evaluating ocean alkalinity enhancement as a carbon dioxide removal strategy in the North Sea
Assessing the impacts of simulated ocean alkalinity enhancement on viability and growth of nearshore species of phytoplankton
Responses of microbial metabolic rates to non-equilibrated silicate- versus calcium-based ocean alkalinity enhancement
High metabolic zinc demand within native Amundsen and Ross sea phytoplankton communities determined by stable isotope uptake rate measurements
The influence of zooplankton and oxygen on the particulate organic carbon flux in the Benguela Upwelling System
Reviews and syntheses: Biological indicators of low-oxygen stress in marine water-breathing animals
Temperature-enhanced effects of iron on Southern Ocean phytoplankton
Riverine nutrient impact on global ocean nitrogen cycle feedbacks and marine primary production in an Earth system model
Effects of Submarine Groundwater on Nutrient Concentration and Primary Production in a Deep Bay of the Japan Sea
The Northeast Greenland Shelf as a potential late-summer CO2 source to the atmosphere
Spring-neap tidal cycles modulate the strength of the carbon source at the estuary-coast interface
Technical note: Ocean Alkalinity Enhancement Pelagic Impact Intercomparison Project (OAEPIIP)
Estimates of carbon sequestration potential in an expanding Arctic fjord (Hornsund, Svalbard) affected by dark plumes of glacial meltwater
An assessment of ocean alkalinity enhancement using aqueous hydroxides: kinetics, efficiency, and precipitation thresholds
Dissolved nitric oxide in the lower Elbe Estuary and the Port of Hamburg area
The bacteria-protist link as a main route of dissolved organic matter across contrasting productivity areas in the Patagonian Shelf
Variable contribution of wastewater treatment plant effluents to downstream nitrous oxide concentrations and emissions
Depositional controls and budget of organic carbon burial in fine-grained sediments of the North Sea – the Helgoland Mud Area as a test field
Improved understanding of eutrophication trends, indicators and problem areas using machine learning
Distribution of nutrients and dissolved organic matter in a eutrophic equatorial estuary: the Johor River and the East Johor Strait
Amplified bottom water acidification rates on the Bering Sea shelf from 1970–2022
Investigating the effect of silicate- and calcium-based ocean alkalinity enhancement on diatom silicification
Ocean alkalinity enhancement using sodium carbonate salts does not lead to measurable changes in Fe dynamics in a mesocosm experiment
Quantification and mitigation of bottom-trawling impacts on sedimentary organic carbon stocks in the North Sea
Influence of ocean alkalinity enhancement with olivine or steel slag on a coastal plankton community in Tasmania
Multi-model comparison of trends and controls of near-bed oxygen concentration on the northwest European continental shelf under climate change
Picoplanktonic methane production in eutrophic surface waters
Vertical mixing alleviates autumnal oxygen deficiency in the central North Sea
Hypoxia also occurs in small highly turbid estuaries: the example of the Charente (Bay of Biscay)
Seasonality and response of ocean acidification and hypoxia to major environmental anomalies in the southern Salish Sea, North America (2014–2018)
Oceanographic processes driving low-oxygen conditions inside Patagonian fjords
Above- and belowground plant mercury dynamics in a salt marsh estuary in Massachusetts, USA
Variability and drivers of carbonate chemistry at shellfish aquaculture sites in the Salish Sea, British Columbia
Unusual Hemiaulus bloom influences ocean productivity in Northeastern US Shelf waters
Insights into carbonate environmental conditions in the Chukchi Sea
UAV approaches for improved mapping of vegetation cover and estimation of carbon storage of small saltmarshes: examples from Loch Fleet, northeast Scotland
Iron “ore” nothing: benthic iron fluxes from the oxygen-deficient Santa Barbara Basin enhance phytoplankton productivity in surface waters
Marine anoxia initiates giant sulfur-oxidizing bacterial mat proliferation and associated changes in benthic nitrogen, sulfur, and iron cycling in the Santa Barbara Basin, California Borderland
Uncertainty in the evolution of northwestern North Atlantic circulation leads to diverging biogeochemical projections
The additionality problem of ocean alkalinity enhancement
Short-term variation in pH in seawaters around coastal areas of Japan: characteristics and forcings
Revisiting the applicability and constraints of molybdenum- and uranium-based paleo redox proxies: comparing two contrasting sill fjords
Influence of a small submarine canyon on biogenic matter export flux in the lower St. Lawrence Estuary, eastern Canada
Single-celled bioturbators: benthic foraminifera mediate oxygen penetration and prokaryotic diversity in intertidal sediment
Assessing impacts of coastal warming, acidification, and deoxygenation on Pacific oyster (Crassostrea gigas) farming: a case study in the Hinase area, Okayama Prefecture, and Shizugawa Bay, Miyagi Prefecture, Japan
Librada Ramírez, Leonardo J. Pozzo-Pirotta, Aja Trebec, Víctor Manzanares-Vázquez, José L. Díez, Javier Arístegui, Ulf Riebesell, Stephen D. Archer, and María Segovia
Biogeosciences, 22, 1865–1886, https://doi.org/10.5194/bg-22-1865-2025, https://doi.org/10.5194/bg-22-1865-2025, 2025
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We studied the potential effects of increasing ocean alkalinity on a natural plankton community in subtropical waters of the Atlantic near Gran Canaria, Spain. Alkalinity is the capacity of water to resist acidification, and plankton are usually microscopic plants (phytoplankton) and animals (zooplankton), often less than 2.5 cm in length. This study suggests that increasing ocean alkalinity did not have a significant negative impact on the plankton community studied.
Leissing Frederick, Mauricio A. Urbina, and Ruben Escribano
Biogeosciences, 22, 1839–1852, https://doi.org/10.5194/bg-22-1839-2025, https://doi.org/10.5194/bg-22-1839-2025, 2025
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Evidence shows that due to global warming, zooplankton inhabiting the coastal upwelling zone are exposed to increasing hypoxia affecting their physiology, metabolism, and population dynamics. The adaptive responses of zooplankton to cope with mild/severe hypoxia may depend on trade-offs with other metabolic/energy demands, implying less energy for growth, feeding, and reproduction, with ecological consequences for the zooplankton population and the marine food web.
Sören Iwe, Oliver Schmale, and Bernd Schneider
Biogeosciences, 22, 1767–1779, https://doi.org/10.5194/bg-22-1767-2025, https://doi.org/10.5194/bg-22-1767-2025, 2025
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We present a novel method for quantifying N2 fixation by cyanobacteria, which is crucial in Baltic Sea eutrophication. Our Gas Equilibrium – Membrane-Inlet Mass Spectrometer (GE-MIMS), designed for operation on voluntary observing ships (VOSs), enables large-scale monitoring of surface water N2 depletion caused by N2 fixation. Laboratory tests confirm the device’s accuracy and precision, ensuring that it can complement current methods and contribute valuable data for better understanding N2 fixation in the Baltic Sea.
Yong-Woo Lee, Mi-Ok Park, Seong-Gil Kim, Tae-Hoon Kim, Yong Hwa Oh, Sang Heon Lee, and DongJoo Joung
Biogeosciences, 22, 675–690, https://doi.org/10.5194/bg-22-675-2025, https://doi.org/10.5194/bg-22-675-2025, 2025
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Long-term pH variation in coastal waters along the Korean Peninsula was assessed for the first time, and it exhibited no significant pH change over an 11-year period. This contrasts with the ongoing pH decline in open oceans and other coastal areas. Analysis of environmental data showed that pH is mainly controlled by dissolved oxygen in bottom waters. This suggests that ocean warming could cause a pH decline in Korean coastal waters, affecting many fish and seaweed aquaculture operations.
Kadir Biçe, Tristen Myers Stewart, George G. Waldbusser, and Christof Meile
Biogeosciences, 22, 641–657, https://doi.org/10.5194/bg-22-641-2025, https://doi.org/10.5194/bg-22-641-2025, 2025
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We studied the effect of addition of carbonate minerals on coastal sediments. We carried out laboratory experiments to quantify the dissolution kinetics and integrated these observations into a numerical model that describes biogeochemical cycling in surficial sediments. Using the model, we demonstrate the buffering effect of the mineral additions and their duration. We quantify the effect under different environmental conditions and assess the potential for increased atmospheric CO2 uptake.
Feifei Liu, Ute Daewel, Jan Kossack, Kubilay Timur Demir, Helmuth Thomas, and Corinna Schrum
EGUsphere, https://doi.org/10.5194/egusphere-2025-81, https://doi.org/10.5194/egusphere-2025-81, 2025
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Ocean Alkalinity Enhancement boosts oceanic CO₂ absorption, offering a climate solution. Using a regional model, we examined OAE in the North Sea, revealing that shallow coastal areas achieve higher CO₂ uptake than offshore, where alkalinity is more susceptible to deep-ocean loss. Long-term carbon storage is limited, and pH shifts vary by location. Our findings guide OAE deployment to optimize carbon removal while minimizing ecological effects, supporting global climate mitigation efforts.
Jessica L. Oberlander, Mackenzie E. Burke, Cat A. London, and Hugh L. MacIntyre
Biogeosciences, 22, 499–512, https://doi.org/10.5194/bg-22-499-2025, https://doi.org/10.5194/bg-22-499-2025, 2025
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Ocean alkalinity enhancement (OAE) is a promising negative emission technology that results in the net sequestration of atmospheric carbon. In this paper, we assess the potential impact of OAE on phytoplankton through an analysis of prior studies and the effects of simulated OAE on photosynthetic competence. Our findings suggest that there may be little if any significant impact on most phytoplankton studied to date if OAE is conducted in well-flushed, nearshore environments.
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, and Ulf Riebesell
Biogeosciences, 21, 5707–5724, https://doi.org/10.5194/bg-21-5707-2024, https://doi.org/10.5194/bg-21-5707-2024, 2024
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This study exposed a natural community to two non-CO2-equilibrated ocean alkalinity enhancement (OAE) deployments using different minerals. Adding alkalinity in this manner decreases dissolved CO2, essential for photosynthesis. While photosynthesis was not suppressed, bloom formation was mildly delayed, potentially impacting marine food webs. The study emphasizes the need for further research on OAE without prior equilibration and on its ecological implications.
Riss M. Kell, Rebecca J. Chmiel, Deepa Rao, Dawn M. Moran, Matthew R. McIlvin, Tristan J. Horner, Nicole L. Schanke, Ichiko Sugiyama, Robert B. Dunbar, Giacomo R. DiTullio, and Mak A. Saito
Biogeosciences, 21, 5685–5706, https://doi.org/10.5194/bg-21-5685-2024, https://doi.org/10.5194/bg-21-5685-2024, 2024
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Despite interest in modeling the biogeochemical uptake and cycling of the trace metal zinc (Zn), measurements of Zn uptake in natural marine phytoplankton communities have not been conducted previously. To fill this gap, we employed a stable isotope uptake rate measurement method to quantify Zn uptake into natural phytoplankton assemblages within the Southern Ocean. Zn demand was high and rapid enough to depress the inventory of Zn available to phytoplankton on seasonal timescales.
Luisa Chiara Meiritz, Tim Rixen, Anja Karin van der Plas, Tarron Lamont, and Niko Lahajnar
Biogeosciences, 21, 5261–5276, https://doi.org/10.5194/bg-21-5261-2024, https://doi.org/10.5194/bg-21-5261-2024, 2024
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Moored and drifting sediment trap experiments in the northern (nBUS) and southern (sBUS) Benguela Upwelling System showed that active carbon fluxes by vertically migrating zooplankton were about 3 times higher in the sBUS than in the nBUS. Despite these large variabilities, the mean passive particulate organic carbon (POC) fluxes were almost equal in the two subsystems. The more intense near-bottom oxygen minimum layer seems to lead to higher POC fluxes and accumulation rates in the nBUS.
Michael R. Roman, Andrew H. Altieri, Denise Breitburg, Erica M. Ferrer, Natalya D. Gallo, Shin-ichi Ito, Karin Limburg, Kenneth Rose, Moriaki Yasuhara, and Lisa A. Levin
Biogeosciences, 21, 4975–5004, https://doi.org/10.5194/bg-21-4975-2024, https://doi.org/10.5194/bg-21-4975-2024, 2024
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Oxygen-depleted ocean waters have increased worldwide. In order to improve our understanding of the impacts of this oxygen loss on marine life it is essential that we develop reliable indicators that track the negative impacts of low oxygen. We review various indicators of low-oxygen stress for marine animals including their use, research needs, and application to confront the challenges of ocean oxygen loss.
Charlotte Eich, Mathijs van Manen, J. Scott P. McCain, Loay J. Jabre, Willem H. van de Poll, Jinyoung Jung, Sven B. E. H. Pont, Hung-An Tian, Indah Ardiningsih, Gert-Jan Reichart, Erin M. Bertrand, Corina P. D. Brussaard, and Rob Middag
Biogeosciences, 21, 4637–4663, https://doi.org/10.5194/bg-21-4637-2024, https://doi.org/10.5194/bg-21-4637-2024, 2024
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Phytoplankton growth in the Southern Ocean (SO) is often limited by low iron (Fe) concentrations. Sea surface warming impacts Fe availability and can affect phytoplankton growth. We used shipboard Fe clean incubations to test how changes in Fe and temperature affect SO phytoplankton. Their abundances usually increased with Fe addition and temperature increase, with Fe being the major factor. These findings imply potential shifts in ecosystem structure, impacting food webs and elemental cycling.
Miriam Tivig, David P. Keller, and Andreas Oschlies
Biogeosciences, 21, 4469–4493, https://doi.org/10.5194/bg-21-4469-2024, https://doi.org/10.5194/bg-21-4469-2024, 2024
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Marine biological production is highly dependent on the availability of nitrogen and phosphorus. Rivers are the main source of phosphorus to the oceans but poorly represented in global model oceans. We include dissolved nitrogen and phosphorus from river export in a global model ocean and find that the addition of riverine phosphorus affects marine biology on millennial timescales more than riverine nitrogen alone. Globally, riverine phosphorus input increases primary production rates.
Menghong Dong, Xinyu Guo, Takuya Matsuura, Taichi Tebakari, and Jing Zhang
EGUsphere, https://doi.org/10.5194/egusphere-2024-2581, https://doi.org/10.5194/egusphere-2024-2581, 2024
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Submarine groundwater discharge (SGD), a common coastal hydrological process that involves submarine inflow of groundwater into the sea, is associated with a large nutrient load. To clarify the distribution of SGD-derived nutrients after release at the bottom of the sea and their contribution to phytoplankton growth in the marine ecosystem, we modeled the SGD process in Toyama Bay using a specialized computer code that can distinguish SGD-derived nutrients from nutrients from other sources.
Esdoorn Willcox, Marcos Lemes, Thomas Juul-Pedersen, Mikael Kristian Sejr, Johnna Marchiano Holding, and Søren Rysgaard
Biogeosciences, 21, 4037–4050, https://doi.org/10.5194/bg-21-4037-2024, https://doi.org/10.5194/bg-21-4037-2024, 2024
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In this work, we measured the chemistry of seawater from samples obtained from different depths and locations off the east coast of the Northeast Greenland National Park to determine what is influencing concentrations of dissolved CO2. Historically, the region has always been thought to take up CO2 from the atmosphere, but we show that it is possible for the region to become a source in late summer. We discuss the variables that may be related to such changes.
Vlad A. Macovei, Louise C. V. Rewrie, Rüdiger Röttgers, and Yoana G. Voynova
EGUsphere, https://doi.org/10.5194/egusphere-2024-2643, https://doi.org/10.5194/egusphere-2024-2643, 2024
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A commercial vessel equipped with scientific instruments regularly travelled between two large macro-tidal estuaries. We found that biogeochemical variability in the outer estuaries is driven by the 14-day spring-neap tidal cycle, with strong effects on dissolved inorganic and organic carbon concentrations and distribution. Since this land-sea interface effect increases the strength of the carbon source to the atmosphere by 74 % during spring tide, it should be accounted for in regional models.
Lennart Thomas Bach, Aaron James Ferderer, Julie LaRoche, and Kai Georg Schulz
Biogeosciences, 21, 3665–3676, https://doi.org/10.5194/bg-21-3665-2024, https://doi.org/10.5194/bg-21-3665-2024, 2024
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Ocean alkalinity enhancement (OAE) is an emerging marine CO2 removal method, but its environmental effects are insufficiently understood. The OAE Pelagic Impact Intercomparison Project (OAEPIIP) provides funding for a standardized and globally replicated microcosm experiment to study the effects of OAE on plankton communities. Here, we provide a detailed manual for the OAEPIIP experiment. We expect OAEPIIP to help build scientific consensus on the effects of OAE on plankton.
Marlena Szeligowska, Déborah Benkort, Anna Przyborska, Mateusz Moskalik, Bernabé Moreno, Emilia Trudnowska, and Katarzyna Błachowiak-Samołyk
Biogeosciences, 21, 3617–3639, https://doi.org/10.5194/bg-21-3617-2024, https://doi.org/10.5194/bg-21-3617-2024, 2024
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The European Arctic is experiencing rapid regional warming, causing glaciers that terminate in the sea to retreat onto land. Due to this process, the area of a well-studied fjord, Hornsund, has increased by around 100 km2 (40%) since 1976. Combining satellite and in situ data with a mathematical model, we estimated that, despite some negative consequences of glacial meltwater release, such emerging coastal waters could mitigate climate change by increasing carbon uptake and storage by sediments.
Mallory C. Ringham, Nathan Hirtle, Cody Shaw, Xi Lu, Julian Herndon, Brendan R. Carter, and Matthew D. Eisaman
Biogeosciences, 21, 3551–3570, https://doi.org/10.5194/bg-21-3551-2024, https://doi.org/10.5194/bg-21-3551-2024, 2024
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Ocean alkalinity enhancement leverages the large surface area and carbon storage capacity of the oceans to store atmospheric CO2 as dissolved bicarbonate. We monitored CO2 uptake in seawater treated with NaOH to establish operational boundaries for carbon removal experiments. Results show that CO2 equilibration occurred on the order of weeks to months, was consistent with values expected from equilibration calculations, and was limited by mineral precipitation at high pH and CaCO3 saturation.
Riel Carlo O. Ingeniero, Gesa Schulz, and Hermann W. Bange
Biogeosciences, 21, 3425–3440, https://doi.org/10.5194/bg-21-3425-2024, https://doi.org/10.5194/bg-21-3425-2024, 2024
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Our research is the first to measure dissolved NO concentrations in temperate estuarine waters, providing insights into its distribution under varying conditions and enhancing our understanding of its production processes. Dissolved NO was supersaturated in the Elbe Estuary, indicating that it is a source of atmospheric NO. The observed distribution of dissolved NO most likely resulted from nitrification.
Celeste López-Abbate, John E. Garzón-Cardona, Ricardo Silva, Juan-Carlos Molinero, Laura A. Ruiz-Etcheverry, Ana M. Martínez, Azul S. Gilabert, and Rubén J. Lara
EGUsphere, https://doi.org/10.5194/egusphere-2024-1860, https://doi.org/10.5194/egusphere-2024-1860, 2024
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This study examines how microbial community structure, growth, and grazing impact the DOM pool in the Patagonian Shelf. Despite higher phytoplankton biomass, faster-growing bacteria were selectively grazed by protists leading to DOM accumulation, likely due to a reduction in DOM-consuming bacteria and the addition of egestion compounds. Experimental data showed that while bacteria remained as the primarily shapers of DOM quality, grazing pressure impacted on DOM accumulation.
Weiyi Tang, Jeff Talbott, Timothy Jones, and Bess B. Ward
Biogeosciences, 21, 3239–3250, https://doi.org/10.5194/bg-21-3239-2024, https://doi.org/10.5194/bg-21-3239-2024, 2024
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Wastewater treatment plants (WWTPs) are known to be hotspots of greenhouse gas emissions. However, the impact of WWTPs on the emission of the greenhouse gas N2O in downstream aquatic environments is less constrained. We found spatially and temporally variable but overall higher N2O concentrations and fluxes in waters downstream of WWTPs, pointing to the need for efficient N2O removal in addition to the treatment of nitrogen in WWTPs.
Daniel Müller, Bo Liu, Walter Geibert, Moritz Holtappels, Lasse Sander, Elda Miramontes, Heidi Taubner, Susann Henkel, Kai-Uwe Hinrichs, Denise Bethke, Ingrid Dohrmann, and Sabine Kasten
EGUsphere, https://doi.org/10.5194/egusphere-2024-1632, https://doi.org/10.5194/egusphere-2024-1632, 2024
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Coastal and shelf sediments are the most important sinks for organic carbon (OC) on Earth. We produced a new high-resolution sediment and pore-water dataset from the Helgoland Mud Area (HMA), North Sea, to determine, which depositional factors control the preservation of OC. The burial efficiency is highest in an area of high sedimentation and terrigenous OC. The HMA covers 0.09 % of the North Sea, but accounts for 0.76 % of its OC accumulation, highlighting the importance of the depocentre.
Deep S. Banerjee and Jozef Skakala
EGUsphere, https://doi.org/10.22541/essoar.171405637.76928549/v1, https://doi.org/10.22541/essoar.171405637.76928549/v1, 2024
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Nitrate is a crucial nutrient in oceans. Excess nutrients can trigger uncontrolled algae growth (eutrophication), damaging marine ecosystems. We used a machine learning tool to generate a skilled, gap-free, bi-decadal surface nitrate dataset from sparse observations. This dataset reveals areas on the North West European Shelf at risk of eutrophication, bi-decadal trends in coastal nitrate, and an impact of winter nitrate on spring phytoplankton blooms.
Amanda Y. L. Cheong, Kogila Vani Annammala, Ee Ling Yong, Yongli Zhou, Robert S. Nichols, and Patrick Martin
Biogeosciences, 21, 2955–2971, https://doi.org/10.5194/bg-21-2955-2024, https://doi.org/10.5194/bg-21-2955-2024, 2024
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We measured nutrients and dissolved organic matter for 1 year in a eutrophic tropical estuary to understand their sources and cycling. Our data show that the dissolved organic matter originates partly from land and partly from microbial processes in the water. Internal recycling is likely important for maintaining high nutrient concentrations, and we found that there is often excess nitrogen compared to silicon and phosphorus. Our data help to explain how eutrophication persists in this system.
Darren Pilcher, Jessica Cross, Natalie Monacci, Linquan Mu, Kelly Kearney, Albert Hermann, and Wei Cheng
EGUsphere, https://doi.org/10.5194/egusphere-2024-1096, https://doi.org/10.5194/egusphere-2024-1096, 2024
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The Bering Sea shelf is a highly productive marine ecosystem that is vulnerable to ocean acidification. We use a computational model to simulate the carbon cycle and acidification rates from 1970–2022. The results suggest that bottom water acidification rates are more than twice as great as surface rates. Bottom waters are also naturally more acidic, thus these waters will pass key thresholds known to negatively impact marine organisms, such as red king crab, much sooner than surface waters.
Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, and Lennart T. Bach
Biogeosciences, 21, 2777–2794, https://doi.org/10.5194/bg-21-2777-2024, https://doi.org/10.5194/bg-21-2777-2024, 2024
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Ocean alkalinity enhancement (OAE) is a promising method of atmospheric carbon removal; however, its ecological impacts remain largely unknown. We assessed the effects of simulated silicate- and calcium-based mineral OAE on diatom silicification. We found that increased silicate concentrations from silicate-based OAE increased diatom silicification. In contrast, the enhancement of alkalinity had no effect on community silicification and minimal effects on the silicification of different genera.
David González-Santana, María Segovia, Melchor González-Dávila, Librada Ramírez, Aridane G. González, Leonardo J. Pozzo-Pirotta, Veronica Arnone, Victor Vázquez, Ulf Riebesell, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 2705–2715, https://doi.org/10.5194/bg-21-2705-2024, https://doi.org/10.5194/bg-21-2705-2024, 2024
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In a recent experiment off the coast of Gran Canaria (Spain), scientists explored a method called ocean alkalinization enhancement (OAE), where carbonate minerals were added to seawater. This process changed the levels of certain ions in the water, affecting its pH and buffering capacity. The researchers were particularly interested in how this could impact the levels of essential trace metals in the water.
Lucas Porz, Wenyan Zhang, Nils Christiansen, Jan Kossack, Ute Daewel, and Corinna Schrum
Biogeosciences, 21, 2547–2570, https://doi.org/10.5194/bg-21-2547-2024, https://doi.org/10.5194/bg-21-2547-2024, 2024
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Seafloor sediments store a large amount of carbon, helping to naturally regulate Earth's climate. If disturbed, some sediment particles can turn into CO2, but this effect is not well understood. Using computer simulations, we found that bottom-contacting fishing gears release about 1 million tons of CO2 per year in the North Sea, one of the most heavily fished regions globally. We show how protecting certain areas could reduce these emissions while also benefitting seafloor-living animals.
Jiaying A. Guo, Robert F. Strzepek, Kerrie M. Swadling, Ashley T. Townsend, and Lennart T. Bach
Biogeosciences, 21, 2335–2354, https://doi.org/10.5194/bg-21-2335-2024, https://doi.org/10.5194/bg-21-2335-2024, 2024
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Ocean alkalinity enhancement aims to increase atmospheric CO2 sequestration by adding alkaline materials to the ocean. We assessed the environmental effects of olivine and steel slag powder on coastal plankton. Overall, slag is more efficient than olivine in releasing total alkalinity and, thus, in its ability to sequester CO2. Slag also had less environmental effect on the enclosed plankton communities when considering its higher CO2 removal potential based on this 3-week experiment.
Giovanni Galli, Sarah Wakelin, James Harle, Jason Holt, and Yuri Artioli
Biogeosciences, 21, 2143–2158, https://doi.org/10.5194/bg-21-2143-2024, https://doi.org/10.5194/bg-21-2143-2024, 2024
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This work shows that, under a high-emission scenario, oxygen concentration in deep water of parts of the North Sea and Celtic Sea can become critically low (hypoxia) towards the end of this century. The extent and frequency of hypoxia depends on the intensity of climate change projected by different climate models. This is the result of a complex combination of factors like warming, increase in stratification, changes in the currents and changes in biological processes.
Sandy E. Tenorio and Laura Farías
Biogeosciences, 21, 2029–2050, https://doi.org/10.5194/bg-21-2029-2024, https://doi.org/10.5194/bg-21-2029-2024, 2024
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Time series studies show that CH4 is highly dynamic on the coastal ocean surface and planktonic communities are linked to CH4 accumulation, as found in coastal upwelling off Chile. We have identified the crucial role of picoplankton (> 3 µm) in CH4 recycling, especially with the addition of methylated substrates (trimethylamine and methylphosphonic acid) during upwelling and non-upwelling periods. These insights improve understanding of surface ocean CH4 recycling, aiding CH4 emission estimates.
Charlotte A. J. Williams, Tom Hull, Jan Kaiser, Claire Mahaffey, Naomi Greenwood, Matthew Toberman, and Matthew R. Palmer
Biogeosciences, 21, 1961–1971, https://doi.org/10.5194/bg-21-1961-2024, https://doi.org/10.5194/bg-21-1961-2024, 2024
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Oxygen (O2) is a key indicator of ocean health. The risk of O2 loss in the productive coastal/continental slope regions is increasing. Autonomous underwater vehicles equipped with O2 optodes provide lots of data but have problems resolving strong vertical O2 changes. Here we show how to overcome this and calculate how much O2 is supplied to the low-O2 bottom waters via mixing. Bursts in mixing supply nearly all of the O2 to bottom waters in autumn, stopping them reaching ecologically low levels.
Sabine Schmidt and Ibrahima Iris Diallo
Biogeosciences, 21, 1785–1800, https://doi.org/10.5194/bg-21-1785-2024, https://doi.org/10.5194/bg-21-1785-2024, 2024
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Along the French coast facing the Bay of Biscay, the large Gironde and Loire estuaries suffer from hypoxia. This prompted a study of the small Charente estuary located between them. This work reveals a minimum oxygen zone in the Charente estuary, which extends for about 25 km. Temperature is the main factor controlling the hypoxia. This calls for the monitoring of small turbid macrotidal estuaries that are vulnerable to hypoxia, a risk expected to increase with global warming.
Simone R. Alin, Jan A. Newton, Richard A. Feely, Samantha Siedlecki, and Dana Greeley
Biogeosciences, 21, 1639–1673, https://doi.org/10.5194/bg-21-1639-2024, https://doi.org/10.5194/bg-21-1639-2024, 2024
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We provide a new multi-stressor data product that allows us to characterize the seasonality of temperature, O2, and CO2 in the southern Salish Sea and delivers insights into the impacts of major marine heatwave and precipitation anomalies on regional ocean acidification and hypoxia. We also describe the present-day frequencies of temperature, O2, and ocean acidification conditions that cross thresholds of sensitive regional species that are economically or ecologically important.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera, Manuel Castillo, Aida Alvera-Azcárate, Mónica Alvarado, Gabriel Soto, Cécile Pujol, Camila Schwerter, Sara Arenas-Uribe, Pilar Navarro, Guido Mancilla-Gutiérrez, Robinson Altamirano, Javiera San Martín, and Camila Soto-Riquelme
Biogeosciences, 21, 1433–1459, https://doi.org/10.5194/bg-21-1433-2024, https://doi.org/10.5194/bg-21-1433-2024, 2024
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The Patagonian fjords comprise a world region where low-oxygen water and hypoxia conditions are observed. An in situ dataset was used to quantify the mechanism involved in the presence of these conditions in northern Patagonian fjords. Water mass analysis confirmed the contribution of Equatorial Subsurface Water in the advection of the low-oxygen water, and hypoxic conditions occurred when the community respiration rate exceeded the gross primary production.
Ting Wang, Buyun Du, Inke Forbrich, Jun Zhou, Joshua Polen, Elsie M. Sunderland, Prentiss H. Balcom, Celia Chen, and Daniel Obrist
Biogeosciences, 21, 1461–1476, https://doi.org/10.5194/bg-21-1461-2024, https://doi.org/10.5194/bg-21-1461-2024, 2024
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The strong seasonal increases of Hg in aboveground biomass during the growing season and the lack of changes observed after senescence in this salt marsh ecosystem suggest physiologically controlled Hg uptake pathways. The Hg sources found in marsh aboveground tissues originate from a mix of sources, unlike terrestrial ecosystems, where atmospheric GEM is the main source. Belowground plant tissues mostly take up Hg from soils. Overall, the salt marsh currently serves as a small net Hg sink.
Eleanor Simpson, Debby Ianson, Karen E. Kohfeld, Ana C. Franco, Paul A. Covert, Marty Davelaar, and Yves Perreault
Biogeosciences, 21, 1323–1353, https://doi.org/10.5194/bg-21-1323-2024, https://doi.org/10.5194/bg-21-1323-2024, 2024
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Shellfish aquaculture operates in nearshore areas where data on ocean acidification parameters are limited. We show daily and seasonal variability in pH and saturation states of calcium carbonate at nearshore aquaculture sites in British Columbia, Canada, and determine the contributing drivers of this variability. We find that nearshore locations have greater variability than open waters and that the uptake of carbon by phytoplankton is the major driver of pH and saturation state variability.
S. Alejandra Castillo Cieza, Rachel H. R. Stanley, Pierre Marrec, Diana N. Fontaine, E. Taylor Crockford, Dennis J. McGillicuddy Jr., Arshia Mehta, Susanne Menden-Deuer, Emily E. Peacock, Tatiana A. Rynearson, Zoe O. Sandwith, Weifeng Zhang, and Heidi M. Sosik
Biogeosciences, 21, 1235–1257, https://doi.org/10.5194/bg-21-1235-2024, https://doi.org/10.5194/bg-21-1235-2024, 2024
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The coastal ocean in the northeastern USA provides many services, including fisheries and habitats for threatened species. In summer 2019, a bloom occurred of a large unusual phytoplankton, the diatom Hemiaulus, with nitrogen-fixing symbionts. This led to vast changes in productivity and grazing rates in the ecosystem. This work shows that the emergence of one species can have profound effects on ecosystem function. Such changes may become more prevalent as the ocean warms due to climate change.
Claudine Hauri, Brita Irving, Sam Dupont, Rémi Pagés, Donna D. W. Hauser, and Seth L. Danielson
Biogeosciences, 21, 1135–1159, https://doi.org/10.5194/bg-21-1135-2024, https://doi.org/10.5194/bg-21-1135-2024, 2024
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Arctic marine ecosystems are highly susceptible to impacts of climate change and ocean acidification. We present pH and pCO2 time series (2016–2020) from the Chukchi Ecosystem Observatory and analyze the drivers of the current conditions to get a better understanding of how climate change and ocean acidification could affect the ecological niches of organisms.
William Hiles, Lucy C. Miller, Craig Smeaton, and William E. N. Austin
Biogeosciences, 21, 929–948, https://doi.org/10.5194/bg-21-929-2024, https://doi.org/10.5194/bg-21-929-2024, 2024
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Saltmarsh soils may help to limit the rate of climate change by storing carbon. To understand their impacts, they must be accurately mapped. We use drone data to estimate the size of three saltmarshes in NE Scotland. We find that drone imagery, combined with tidal data, can reliably inform our understanding of saltmarsh size. When compared with previous work using vegetation communities, we find that our most reliable new estimates of stored carbon are 15–20 % smaller than previously estimated.
De'Marcus Robinson, Anh L. D. Pham, David J. Yousavich, Felix Janssen, Frank Wenzhöfer, Eleanor C. Arrington, Kelsey M. Gosselin, Marco Sandoval-Belmar, Matthew Mar, David L. Valentine, Daniele Bianchi, and Tina Treude
Biogeosciences, 21, 773–788, https://doi.org/10.5194/bg-21-773-2024, https://doi.org/10.5194/bg-21-773-2024, 2024
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The present study suggests that high release of ferrous iron from the seafloor of the oxygen-deficient Santa Barabara Basin (California) supports surface primary productivity, creating positive feedback on seafloor iron release by enhancing low-oxygen conditions in the basin.
David J. Yousavich, De'Marcus Robinson, Xuefeng Peng, Sebastian J. E. Krause, Frank Wenzhöfer, Felix Janssen, Na Liu, Jonathan Tarn, Franklin Kinnaman, David L. Valentine, and Tina Treude
Biogeosciences, 21, 789–809, https://doi.org/10.5194/bg-21-789-2024, https://doi.org/10.5194/bg-21-789-2024, 2024
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Declining oxygen (O2) concentrations in coastal oceans can threaten people’s ways of life and food supplies. Here, we investigate how mats of bacteria that proliferate on the seafloor of the Santa Barbara Basin sustain and potentially worsen these O2 depletion events through their unique chemoautotrophic metabolism. Our study shows how changes in seafloor microbiology and geochemistry brought on by declining O2 concentrations can help these mats grow as well as how that growth affects the basin.
Krysten Rutherford, Katja Fennel, Lina Garcia Suarez, and Jasmin G. John
Biogeosciences, 21, 301–314, https://doi.org/10.5194/bg-21-301-2024, https://doi.org/10.5194/bg-21-301-2024, 2024
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We downscaled two mid-century (~2075) ocean model projections to a high-resolution regional ocean model of the northwest North Atlantic (NA) shelf. In one projection, the NA shelf break current practically disappears; in the other it remains almost unchanged. This leads to a wide range of possible future shelf properties. More accurate projections of coastal circulation features would narrow the range of possible outcomes of biogeochemical projections for shelf regions.
Lennart Thomas Bach
Biogeosciences, 21, 261–277, https://doi.org/10.5194/bg-21-261-2024, https://doi.org/10.5194/bg-21-261-2024, 2024
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Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.
Tsuneo Ono, Daisuke Muraoka, Masahiro Hayashi, Makiko Yorifuji, Akihiro Dazai, Shigeyuki Omoto, Takehiro Tanaka, Tomohiro Okamura, Goh Onitsuka, Kenji Sudo, Masahiko Fujii, Ryuji Hamanoue, and Masahide Wakita
Biogeosciences, 21, 177–199, https://doi.org/10.5194/bg-21-177-2024, https://doi.org/10.5194/bg-21-177-2024, 2024
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We carried out parallel year-round observations of pH and related parameters in five stations around the Japan coast. It was found that short-term acidified situations with Omega_ar less than 1.5 occurred at four of five stations. Most of such short-term acidified events were related to the short-term low salinity event, and the extent of short-term pH drawdown at high freshwater input was positively correlated with the nutrient concentration of the main rivers that flow into the coastal area.
K. Mareike Paul, Martijn Hermans, Sami A. Jokinen, Inda Brinkmann, Helena L. Filipsson, and Tom Jilbert
Biogeosciences, 20, 5003–5028, https://doi.org/10.5194/bg-20-5003-2023, https://doi.org/10.5194/bg-20-5003-2023, 2023
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Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.
Hannah Sharpe, Michel Gosselin, Catherine Lalande, Alexandre Normandeau, Jean-Carlos Montero-Serrano, Khouloud Baccara, Daniel Bourgault, Owen Sherwood, and Audrey Limoges
Biogeosciences, 20, 4981–5001, https://doi.org/10.5194/bg-20-4981-2023, https://doi.org/10.5194/bg-20-4981-2023, 2023
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We studied the impact of submarine canyon processes within the Pointe-des-Monts system on biogenic matter export and phytoplankton assemblages. Using data from three oceanographic moorings, we show that the canyon experienced two low-amplitude sediment remobilization events in 2020–2021 that led to enhanced particle fluxes in the deep-water column layer > 2.6 km offshore. Sinking phytoplankton fluxes were lower near the canyon compared to background values from the lower St. Lawrence Estuary.
Dewi Langlet, Florian Mermillod-Blondin, Noémie Deldicq, Arthur Bauville, Gwendoline Duong, Lara Konecny, Mylène Hugoni, Lionel Denis, and Vincent M. P. Bouchet
Biogeosciences, 20, 4875–4891, https://doi.org/10.5194/bg-20-4875-2023, https://doi.org/10.5194/bg-20-4875-2023, 2023
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Benthic foraminifera are single-cell marine organisms which can move in the sediment column. They were previously reported to horizontally and vertically transport sediment particles, yet the impact of their motion on the dissolved fluxes remains unknown. Using microprofiling, we show here that foraminiferal burrow formation increases the oxygen penetration depth in the sediment, leading to a change in the structure of the prokaryotic community.
Masahiko Fujii, Ryuji Hamanoue, Lawrence Patrick Cases Bernardo, Tsuneo Ono, Akihiro Dazai, Shigeyuki Oomoto, Masahide Wakita, and Takehiro Tanaka
Biogeosciences, 20, 4527–4549, https://doi.org/10.5194/bg-20-4527-2023, https://doi.org/10.5194/bg-20-4527-2023, 2023
Short summary
Short summary
This is the first study of the current and future impacts of climate change on Pacific oyster farming in Japan. Future coastal warming and acidification may affect oyster larvae as a result of longer exposure to lower-pH waters. A prolonged spawning period may harm oyster processing by shortening the shipping period and reducing oyster quality. To minimize impacts on Pacific oyster farming, in addition to mitigation measures, local adaptation measures may be required.
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Short summary
Fe is an essential micronutrient. Fe(III)-organic species are thought to account for > 99 % of dissolved Fe in seawater. Here we quantified Fe(II) during experiments in Svalbard, Gran Canaria, and Patagonia. Fe(II) was always a measurable fraction of dissolved Fe up to 65 %. Furthermore, when Fe(II) was allowed to decay in the dark, it remained present longer than predicted by kinetic equations, suggesting that Fe(II) is a more important fraction of dissolved Fe in seawater than widely recognized.
Fe is an essential micronutrient. Fe(III)-organic species are thought to account for 99 % of...
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