Articles | Volume 20, issue 14
https://doi.org/10.5194/bg-20-3073-2023
© Author(s) 2023. 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-20-3073-2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone
Asmita Singh
Department of Earth Sciences, University of Stellenbosch,
Stellenbosch, South Africa
Southern Ocean Carbon–Climate Observatory, CSIR, Cape Town, South
Africa
Susanne Fietz
Department of Earth Sciences, University of Stellenbosch,
Stellenbosch, South Africa
Sandy J. Thomalla
Southern Ocean Carbon–Climate Observatory, CSIR, Cape Town, South
Africa
Marine and Antarctic Research for Innovation and Sustainability, University of Cape Town, Cape Town, South Africa
Nicolas Sanchez
Department of Chemistry, Norwegian University of Science and
Technology (NTNU), Trondheim, Norway
Murat V. Ardelan
Department of Chemistry, Norwegian University of Science and
Technology (NTNU), Trondheim, Norway
Sébastien Moreau
Norwegian Polar Institute (NPI), Tromsø, Norway
Centre for Ice, Cryosphere, Carbon and Climate, Department of
Geosciences, UiT, The Arctic University of Norway, Tromsø, Norway
Hanna M. Kauko
Norwegian Polar Institute (NPI), Tromsø, Norway
Agneta Fransson
Norwegian Polar Institute (NPI), Tromsø, Norway
Melissa Chierici
Institute of Marine Research, Fram Centre, Tromsø, Norway
Saumik Samanta
Department of Earth Sciences, University of Stellenbosch,
Stellenbosch, South Africa
Thato N. Mtshali
Oceans and Coasts, Department of Forestry, Fisheries, and the Environment,
Cape Town, South Africa
Alakendra N. Roychoudhury
Department of Earth Sciences, University of Stellenbosch,
Stellenbosch, South Africa
Thomas J. Ryan-Keogh
CORRESPONDING AUTHOR
Southern Ocean Carbon–Climate Observatory, CSIR, Cape Town, South
Africa
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Hanna M. Kauko, Philipp Assmy, Ilka Peeken, Magdalena Różańska-Pluta, Józef M. Wiktor, Gunnar Bratbak, Asmita Singh, Thomas J. Ryan-Keogh, and Sebastien Moreau
Biogeosciences, 19, 5449–5482, https://doi.org/10.5194/bg-19-5449-2022, https://doi.org/10.5194/bg-19-5449-2022, 2022
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This article studies phytoplankton (microscopic
plantsin the ocean capable of photosynthesis) in Kong Håkon VII Hav in the Southern Ocean. Different species play different roles in the ecosystem, and it is therefore important to assess the species composition. We observed that phytoplankton blooms in this area are formed by large diatoms with strong silica armors, which can lead to high silica (and sometimes carbon) export to depth and be important prey for krill.
Julius Lauber, Tore Hattermann, Laura de Steur, Elin Darelius, and Agneta Fransson
EGUsphere, https://doi.org/10.5194/egusphere-2024-904, https://doi.org/10.5194/egusphere-2024-904, 2024
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Recent studies have highlighted the potential vulnerability of the East Antarctic Ice Sheet to atmospheric and oceanic changes. We present new insights from observations from three oceanic moorings below Fimbulisen Ice Shelf from 2009 to 2021. We find that relatively warm water masses reach below the ice shelf both close to the surface and at depth with implications for the basal melting of Fimbulisen.
Sarah-Anne Nicholson, Thomas J. Ryan-Keogh, Sandy J. Thomalla, Nicolette Chang, and Marié E. Smith
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2024-21, https://doi.org/10.5194/essd-2024-21, 2024
Preprint under review for ESSD
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The annual greening of the global ocean by the widespread growth of phytoplankton blooms, visible from space, has global-scale impacts on food security, ecosystem health, and climate. Using satellite observations this study generates long-term and sustained phytoplankton phenology (timing and magnitude of blooms) indices for the global ocean towards the effective monitoring and management of marine resources and the assessment of climate change impacts on ocean ecosystems
Morgane M. G. Perron, Susanne Fietz, Douglas S. Hamilton, Akinori Ito, Rachel U. Shelley, and Mingjin Tang
Atmos. Meas. Tech., 17, 165–166, https://doi.org/10.5194/amt-17-165-2024, https://doi.org/10.5194/amt-17-165-2024, 2024
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The solubility of vital and toxic trace elements delivered by the atmosphere determines their potential to fertilise or limit ocean productivity. A poor understanding of aeolian trace element solubility and the absence of a standard method to define this parameter hinder accurate model representation of the impact of atmospheric deposition on ocean productivity in a changing climate. The inter-journal special issue aims at “Reducing Uncertainty in Soluble aerosol Trace Element Deposition”.
Thomas J. Ryan-Keogh, Sandy J. Thomalla, Nicolette Chang, and Tumelo Moalusi
Earth Syst. Sci. Data, 15, 4829–4848, https://doi.org/10.5194/essd-15-4829-2023, https://doi.org/10.5194/essd-15-4829-2023, 2023
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Oceanic productivity has been highlighted as an important environmental indicator of climate change in comparison to other existing metrics. However, the availability of these data to assess trends and trajectories is plagued with issues, such as application to only a single satellite reducing the time period for assessment. We have applied multiple algorithms to the longest ocean colour record to provide a record for assessing climate-change-driven trends.
Christoph Heinze, Thorsten Blenckner, Peter Brown, Friederike Fröb, Anne Morée, Adrian L. New, Cara Nissen, Stefanie Rynders, Isabel Seguro, Yevgeny Aksenov, Yuri Artioli, Timothée Bourgeois, Friedrich Burger, Jonathan Buzan, B. B. Cael, Veli Çağlar Yumruktepe, Melissa Chierici, Christopher Danek, Ulf Dieckmann, Agneta Fransson, Thomas Frölicher, Giovanni Galli, Marion Gehlen, Aridane G. González, Melchor Gonzalez-Davila, Nicolas Gruber, Örjan Gustafsson, Judith Hauck, Mikko Heino, Stephanie Henson, Jenny Hieronymus, I. Emma Huertas, Fatma Jebri, Aurich Jeltsch-Thömmes, Fortunat Joos, Jaideep Joshi, Stephen Kelly, Nandini Menon, Precious Mongwe, Laurent Oziel, Sólveig Ólafsdottir, Julien Palmieri, Fiz F. Pérez, Rajamohanan Pillai Ranith, Juliano Ramanantsoa, Tilla Roy, Dagmara Rusiecka, J. Magdalena Santana Casiano, Yeray Santana-Falcón, Jörg Schwinger, Roland Séférian, Miriam Seifert, Anna Shchiptsova, Bablu Sinha, Christopher Somes, Reiner Steinfeldt, Dandan Tao, Jerry Tjiputra, Adam Ulfsbo, Christoph Völker, Tsuyoshi Wakamatsu, and Ying Ye
Biogeosciences Discuss., https://doi.org/10.5194/bg-2023-182, https://doi.org/10.5194/bg-2023-182, 2023
Preprint under review for BG
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For assessing the consequences of human-induced climate change for the marine realm, it is necessary to not only look at gradual changes but also at abrupt changes of environmental conditions. We summarise abrupt changes in ocean warming, acidification, and oxygen concentration as the key environmental factors for ecosystems. Taking these abrupt changes into account requires greenhouse gas emissions to be reduced to a larger extent than previously thought to limit respective damage.
Hanna M. Kauko, Philipp Assmy, Ilka Peeken, Magdalena Różańska-Pluta, Józef M. Wiktor, Gunnar Bratbak, Asmita Singh, Thomas J. Ryan-Keogh, and Sebastien Moreau
Biogeosciences, 19, 5449–5482, https://doi.org/10.5194/bg-19-5449-2022, https://doi.org/10.5194/bg-19-5449-2022, 2022
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This article studies phytoplankton (microscopic
plantsin the ocean capable of photosynthesis) in Kong Håkon VII Hav in the Southern Ocean. Different species play different roles in the ecosystem, and it is therefore important to assess the species composition. We observed that phytoplankton blooms in this area are formed by large diatoms with strong silica armors, which can lead to high silica (and sometimes carbon) export to depth and be important prey for krill.
Julian Gutt, Stefanie Arndt, David Keith Alan Barnes, Horst Bornemann, Thomas Brey, Olaf Eisen, Hauke Flores, Huw Griffiths, Christian Haas, Stefan Hain, Tore Hattermann, Christoph Held, Mario Hoppema, Enrique Isla, Markus Janout, Céline Le Bohec, Heike Link, Felix Christopher Mark, Sebastien Moreau, Scarlett Trimborn, Ilse van Opzeeland, Hans-Otto Pörtner, Fokje Schaafsma, Katharina Teschke, Sandra Tippenhauer, Anton Van de Putte, Mia Wege, Daniel Zitterbart, and Dieter Piepenburg
Biogeosciences, 19, 5313–5342, https://doi.org/10.5194/bg-19-5313-2022, https://doi.org/10.5194/bg-19-5313-2022, 2022
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Long-term ecological observations are key to assess, understand and predict impacts of environmental change on biotas. We present a multidisciplinary framework for such largely lacking investigations in the East Antarctic Southern Ocean, combined with case studies, experimental and modelling work. As climate change is still minor here but is projected to start soon, the timely implementation of this framework provides the unique opportunity to document its ecological impacts from the very onset.
Mhlangabezi Mdutyana, Tanya Marshall, Xin Sun, Jessica M. Burger, Sandy J. Thomalla, Bess B. Ward, and Sarah E. Fawcett
Biogeosciences, 19, 3425–3444, https://doi.org/10.5194/bg-19-3425-2022, https://doi.org/10.5194/bg-19-3425-2022, 2022
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Nitrite-oxidizing bacteria in the winter Southern Ocean show a high affinity for nitrite but require a minimum (i.e., "threshold") concentration before they increase their rates of nitrite oxidation significantly. The classic Michaelis–Menten model thus cannot be used to derive the kinetic parameters, so a modified equation was employed that also yields the threshold nitrite concentration. Dissolved iron availability may play an important role in limiting nitrite oxidation.
Natasha René van Horsten, Hélène Planquette, Géraldine Sarthou, Thomas James Ryan-Keogh, Nolwenn Lemaitre, Thato Nicholas Mtshali, Alakendra Roychoudhury, and Eva Bucciarelli
Biogeosciences, 19, 3209–3224, https://doi.org/10.5194/bg-19-3209-2022, https://doi.org/10.5194/bg-19-3209-2022, 2022
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The remineralisation proxy, barite, was measured along 30°E in the southern Indian Ocean during early austral winter. To our knowledge this is the first reported Southern Ocean winter study. Concentrations throughout the water column were comparable to observations during spring to autumn. By linking satellite primary production to this proxy a possible annual timescale is proposed. These findings also suggest possible carbon remineralisation from satellite data on a basin scale.
Filippa Fransner, Friederike Fröb, Jerry Tjiputra, Nadine Goris, Siv K. Lauvset, Ingunn Skjelvan, Emil Jeansson, Abdirahman Omar, Melissa Chierici, Elizabeth Jones, Agneta Fransson, Sólveig R. Ólafsdóttir, Truls Johannessen, and Are Olsen
Biogeosciences, 19, 979–1012, https://doi.org/10.5194/bg-19-979-2022, https://doi.org/10.5194/bg-19-979-2022, 2022
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Ocean acidification, a direct consequence of the CO2 release by human activities, is a serious threat to marine ecosystems. In this study, we conduct a detailed investigation of the acidification of the Nordic Seas, from 1850 to 2100, by using a large set of samples taken during research cruises together with numerical model simulations. We estimate the effects of changes in different environmental factors on the rate of acidification and its potential effects on cold-water corals.
Tobias Reiner Vonnahme, Emma Persson, Ulrike Dietrich, Eva Hejdukova, Christine Dybwad, Josef Elster, Melissa Chierici, and Rolf Gradinger
The Cryosphere, 15, 2083–2107, https://doi.org/10.5194/tc-15-2083-2021, https://doi.org/10.5194/tc-15-2083-2021, 2021
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We describe the impact of subglacial discharge in early spring on a sea-ice-covered fjord on Svalbard by comparing a site influenced by a shallow tidewater glacier with two reference sites. We found a moderate under-ice phytoplankton bloom at the glacier front, which we attribute to subglacial upwelling of nutrients; a strongly stratified surface layer; and higher light penetration. In contrast, sea ice algae biomass was limited by low salinities and brine volumes.
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?
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.
Mark J. Hopwood, Carolina Santana-González, Julian Gallego-Urrea, Nicolas Sanchez, Eric P. Achterberg, Murat V. Ardelan, Martha Gledhill, Melchor González-Dávila, Linn Hoffmann, Øystein Leiknes, Juana Magdalena Santana-Casiano, Tatiana M. Tsagaraki, and David Turner
Biogeosciences, 17, 1327–1342, https://doi.org/10.5194/bg-17-1327-2020, https://doi.org/10.5194/bg-17-1327-2020, 2020
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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.
Filippa Fransner, Agneta Fransson, Christoph Humborg, Erik Gustafsson, Letizia Tedesco, Robinson Hordoir, and Jonas Nycander
Biogeosciences, 16, 863–879, https://doi.org/10.5194/bg-16-863-2019, https://doi.org/10.5194/bg-16-863-2019, 2019
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Although rivers carry large amounts of organic material to the oceans, little is known about what fate it meets when it reaches the sea. In this study we are investigating the fate of the carbon in this organic matter by the use of a numerical model in combination with ship measurements from the northern Baltic Sea. Our results suggests that there is substantial remineralization taking place, transforming the organic carbon into CO2, which is released to the atmosphere.
Thomas J. Ryan-Keogh, Sandy J. Thomalla, Thato N. Mtshali, Natasha R. van Horsten, and Hazel J. Little
Biogeosciences, 15, 4647–4660, https://doi.org/10.5194/bg-15-4647-2018, https://doi.org/10.5194/bg-15-4647-2018, 2018
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The availability of iron in the Southern Ocean constrains the overall extent and magnitude of the phytoplankton bloom. Uncertainty remains over the dominant supply mechanisms, which are expected to be altered by climate change. Nutrient addition experiments confirm that iron limitation is seasonal in nature, with increased responses to iron addition in late summer. This is driven by variability in the supply mechanisms across the growing season, which fail to meet the phytoplankton demand.
Daiki Nomura, Mats A. Granskog, Agneta Fransson, Melissa Chierici, Anna Silyakova, Kay I. Ohshima, Lana Cohen, Bruno Delille, Stephen R. Hudson, and Gerhard S. Dieckmann
Biogeosciences, 15, 3331–3343, https://doi.org/10.5194/bg-15-3331-2018, https://doi.org/10.5194/bg-15-3331-2018, 2018
Sayaka Yasunaka, Eko Siswanto, Are Olsen, Mario Hoppema, Eiji Watanabe, Agneta Fransson, Melissa Chierici, Akihiko Murata, Siv K. Lauvset, Rik Wanninkhof, Taro Takahashi, Naohiro Kosugi, Abdirahman M. Omar, Steven van Heuven, and Jeremy T. Mathis
Biogeosciences, 15, 1643–1661, https://doi.org/10.5194/bg-15-1643-2018, https://doi.org/10.5194/bg-15-1643-2018, 2018
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We estimated monthly air–sea CO2 fluxes in the Arctic Ocean and its adjacent seas north of 60° N from 1997 to 2014, after mapping pCO2 in the surface water using a self-organizing map technique. The addition of Chl a as a parameter enabled us to improve the estimate of pCO2 via better representation of its decline in spring. The uncertainty in the CO2 flux estimate was reduced, and a net annual Arctic Ocean CO2 uptake of 180 ± 130 Tg C y−1 was determined to be significant.
Thomas J. Ryan-Keogh, Sandy J. Thomalla, Thato N. Mtshali, and Hazel Little
Biogeosciences, 14, 3883–3897, https://doi.org/10.5194/bg-14-3883-2017, https://doi.org/10.5194/bg-14-3883-2017, 2017
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Primary production in the Southern Ocean is a key contributor to mitigating global anthropogenic carbon dioxide; however, the controlling mechanisms are poorly understood. A series of experiments were performed to look at whether the rates of primary production are limited by the biogeochemically important micronutrient iron. The results demonstrate that any global climate models that do not take into account the effect of iron availability could underestimate primary production by up to 80 %.
Dorothee C. E. Bakker, Benjamin Pfeil, Camilla S. Landa, Nicolas Metzl, Kevin M. O'Brien, Are Olsen, Karl Smith, Cathy Cosca, Sumiko Harasawa, Stephen D. Jones, Shin-ichiro Nakaoka, Yukihiro Nojiri, Ute Schuster, Tobias Steinhoff, Colm Sweeney, Taro Takahashi, Bronte Tilbrook, Chisato Wada, Rik Wanninkhof, Simone R. Alin, Carlos F. Balestrini, Leticia Barbero, Nicholas R. Bates, Alejandro A. Bianchi, Frédéric Bonou, Jacqueline Boutin, Yann Bozec, Eugene F. Burger, Wei-Jun Cai, Robert D. Castle, Liqi Chen, Melissa Chierici, Kim Currie, Wiley Evans, Charles Featherstone, Richard A. Feely, Agneta Fransson, Catherine Goyet, Naomi Greenwood, Luke Gregor, Steven Hankin, Nick J. Hardman-Mountford, Jérôme Harlay, Judith Hauck, Mario Hoppema, Matthew P. Humphreys, Christopher W. Hunt, Betty Huss, J. Severino P. Ibánhez, Truls Johannessen, Ralph Keeling, Vassilis Kitidis, Arne Körtzinger, Alex Kozyr, Evangelia Krasakopoulou, Akira Kuwata, Peter Landschützer, Siv K. Lauvset, Nathalie Lefèvre, Claire Lo Monaco, Ansley Manke, Jeremy T. Mathis, Liliane Merlivat, Frank J. Millero, Pedro M. S. Monteiro, David R. Munro, Akihiko Murata, Timothy Newberger, Abdirahman M. Omar, Tsuneo Ono, Kristina Paterson, David Pearce, Denis Pierrot, Lisa L. Robbins, Shu Saito, Joe Salisbury, Reiner Schlitzer, Bernd Schneider, Roland Schweitzer, Rainer Sieger, Ingunn Skjelvan, Kevin F. Sullivan, Stewart C. Sutherland, Adrienne J. Sutton, Kazuaki Tadokoro, Maciej Telszewski, Matthias Tuma, Steven M. A. C. van Heuven, Doug Vandemark, Brian Ward, Andrew J. Watson, and Suqing Xu
Earth Syst. Sci. Data, 8, 383–413, https://doi.org/10.5194/essd-8-383-2016, https://doi.org/10.5194/essd-8-383-2016, 2016
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Version 3 of the Surface Ocean CO2 Atlas (www.socat.info) has 14.5 million CO2 (carbon dioxide) values for the years 1957 to 2014 covering the global oceans and coastal seas. Version 3 is an update to version 2 with a longer record and 44 % more CO2 values. The CO2 measurements have been made on ships, fixed moorings and drifting buoys. SOCAT enables quantification of the ocean carbon sink and ocean acidification, as well as model evaluation, thus informing climate negotiations.
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
W. R. Joubert, S. Swart, A. Tagliabue, S. J. Thomalla, and P. M. S. Monteiro
Biogeosciences Discuss., https://doi.org/10.5194/bgd-11-4335-2014, https://doi.org/10.5194/bgd-11-4335-2014, 2014
Revised manuscript not accepted
D. C. E. Bakker, B. Pfeil, K. Smith, S. Hankin, A. Olsen, S. R. Alin, C. Cosca, S. Harasawa, A. Kozyr, Y. Nojiri, K. M. O'Brien, U. Schuster, M. Telszewski, B. Tilbrook, C. Wada, J. Akl, L. Barbero, N. R. Bates, J. Boutin, Y. Bozec, W.-J. Cai, R. D. Castle, F. P. Chavez, L. Chen, M. Chierici, K. Currie, H. J. W. de Baar, W. Evans, R. A. Feely, A. Fransson, Z. Gao, B. Hales, N. J. Hardman-Mountford, M. Hoppema, W.-J. Huang, C. W. Hunt, B. Huss, T. Ichikawa, T. Johannessen, E. M. Jones, S. D. Jones, S. Jutterström, V. Kitidis, A. Körtzinger, P. Landschützer, S. K. Lauvset, N. Lefèvre, A. B. Manke, J. T. Mathis, L. Merlivat, N. Metzl, A. Murata, T. Newberger, A. M. Omar, T. Ono, G.-H. Park, K. Paterson, D. Pierrot, A. F. Ríos, C. L. Sabine, S. Saito, J. Salisbury, V. V. S. S. Sarma, R. Schlitzer, R. Sieger, I. Skjelvan, T. Steinhoff, K. F. Sullivan, H. Sun, A. J. Sutton, T. Suzuki, C. Sweeney, T. Takahashi, J. Tjiputra, N. Tsurushima, S. M. A. C. van Heuven, D. Vandemark, P. Vlahos, D. W. R. Wallace, R. Wanninkhof, and A. J. Watson
Earth Syst. Sci. Data, 6, 69–90, https://doi.org/10.5194/essd-6-69-2014, https://doi.org/10.5194/essd-6-69-2014, 2014
M. Mattsdotter Björk, A. Fransson, A. Torstensson, and M. Chierici
Biogeosciences, 11, 57–73, https://doi.org/10.5194/bg-11-57-2014, https://doi.org/10.5194/bg-11-57-2014, 2014
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Shunya Koseki, Lander R. Crespo, Jerry Tjiputra, Filippa Fransner, Noel S. Keenlyside, and David Rivas
Biogeosciences, 21, 4149–4168, https://doi.org/10.5194/bg-21-4149-2024, https://doi.org/10.5194/bg-21-4149-2024, 2024
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We investigated how the physical biases of an Earth system model influence the marine biogeochemical processes in the tropical Atlantic. With four different configurations of the model, we have shown that the versions with better SST reproduction tend to better represent the primary production and air–sea CO2 flux in terms of climatology, seasonal cycle, and response to climate variability.
Lyuba Novi, Annalisa Bracco, Takamitsu Ito, and Yohei Takano
Biogeosciences, 21, 3985–4005, https://doi.org/10.5194/bg-21-3985-2024, https://doi.org/10.5194/bg-21-3985-2024, 2024
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We explored the relationship between oxygen and stratification in the North Pacific Ocean using a combination of data mining and machine learning. We used isopycnic potential vorticity (IPV) as an indicator to quantify ocean ventilation and analyzed its predictability, a strong O2–IPV connection, and predictability for IPV in the tropical Pacific. This opens new routes for monitoring ocean O2 through few observational sites co-located with more abundant IPV measurements in the tropical Pacific.
Winfred Marshal, Jing Xiang Chung, Nur Hidayah Roseli, Roswati Md Amin, and Mohd Fadzil Bin Mohd Akhir
Biogeosciences, 21, 4007–4035, https://doi.org/10.5194/bg-21-4007-2024, https://doi.org/10.5194/bg-21-4007-2024, 2024
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This study stands out for thoroughly examining CMIP6 ESMs' ability to simulate biogeochemical variables in the southern South China Sea, an economically important region. It assesses variables like chlorophyll, phytoplankton, nitrate, and oxygen on annual and seasonal scales. While global assessments exist, this study addresses a gap by objectively ranking 13 CMIP6 ocean biogeochemistry models' performance at a regional level, focusing on replicating specific observed biogeochemical variables.
Jens Terhaar
Biogeosciences, 21, 3903–3926, https://doi.org/10.5194/bg-21-3903-2024, https://doi.org/10.5194/bg-21-3903-2024, 2024
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Despite the ocean’s importance in the carbon cycle and hence the climate, observing the ocean carbon sink remains challenging. Here, I use an ensemble of 12 models to understand drivers of decadal trends of the past, present, and future ocean carbon sink. I show that 80 % of the decadal trends in the multi-model mean ocean carbon sink can be explained by changes in decadal trends in atmospheric CO2. The remaining 20 % are due to internal climate variability and ocean heat uptake.
Reiner Steinfeldt, Monika Rhein, and Dagmar Kieke
Biogeosciences, 21, 3839–3867, https://doi.org/10.5194/bg-21-3839-2024, https://doi.org/10.5194/bg-21-3839-2024, 2024
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We calculate the amount of anthropogenic carbon (Cant) in the Atlantic for the years 1990, 2000, 2010 and 2020. Cant is the carbon that is taken up by the ocean as a result of humanmade CO2 emissions. To determine the amount of Cant, we apply a technique that is based on the observations of other humanmade gases (e.g., chlorofluorocarbons). Regionally, changes in ocean ventilation have an impact on the storage of Cant. Overall, the increase in Cant is driven by the rising CO2 in the atmosphere.
Stephanie Delacroix, Tor Jensen Nystuen, August E. Dessen Tobiesen, Andrew L. King, and Erik Höglund
Biogeosciences, 21, 3677–3690, https://doi.org/10.5194/bg-21-3677-2024, https://doi.org/10.5194/bg-21-3677-2024, 2024
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The addition of alkaline minerals into the ocean might reduce excessive anthropogenic CO2 emissions. Magnesium hydroxide can be added in large amounts because of its low seawater solubility without reaching harmful pH levels. The toxicity effect results of magnesium hydroxide, by simulating the expected concentrations from a ship's dispersion scenario, demonstrated low impacts on both sensitive and local assemblages of marine microalgae when compared to calcium hydroxide.
Precious Mongwe, Matthew Long, Takamitsu Ito, Curtis Deutsch, and Yeray Santana-Falcón
Biogeosciences, 21, 3477–3490, https://doi.org/10.5194/bg-21-3477-2024, https://doi.org/10.5194/bg-21-3477-2024, 2024
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We use a collection of measurements that capture the physiological sensitivity of organisms to temperature and oxygen and a CESM1 large ensemble to investigate how natural climate variations and climate warming will impact the ability of marine heterotrophic marine organisms to support habitats in the future. We find that warming and dissolved oxygen loss over the next several decades will reduce the volume of ocean habitats and will increase organisms' vulnerability to extremes.
Charly A. Moras, Tyler Cyronak, Lennart T. Bach, Renaud Joannes-Boyau, and Kai G. Schulz
Biogeosciences, 21, 3463–3475, https://doi.org/10.5194/bg-21-3463-2024, https://doi.org/10.5194/bg-21-3463-2024, 2024
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We investigate the effects of mineral grain size and seawater salinity on magnesium hydroxide dissolution and calcium carbonate precipitation kinetics for ocean alkalinity enhancement. Salinity did not affect the dissolution, but calcium carbonate formed earlier at lower salinities due to the lower magnesium and dissolved organic carbon concentrations. Smaller grain sizes dissolved faster but calcium carbonate precipitated earlier, suggesting that medium grain sizes are optimal for kinetics.
Rosie M. Sheward, Christina Gebühr, Jörg Bollmann, and Jens O. Herrle
Biogeosciences, 21, 3121–3141, https://doi.org/10.5194/bg-21-3121-2024, https://doi.org/10.5194/bg-21-3121-2024, 2024
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How quickly do marine microorganisms respond to salinity stress? Our experiments with the calcifying marine plankton Emiliania huxleyi show that growth and cell morphology responded to salinity stress within as little as 24–48 hours, demonstrating that morphology and calcification are sensitive to salinity over a range of timescales. Our results have implications for understanding the short-term role of E. huxleyi in biogeochemical cycles and in size-based paleoproxies for salinity.
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, Joaquín Ortiz, Stephen D. Archer, Andrea Ludwig, and Ulf Riebesell
Biogeosciences, 21, 2859–2876, https://doi.org/10.5194/bg-21-2859-2024, https://doi.org/10.5194/bg-21-2859-2024, 2024
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Our planet is facing a climate crisis. Scientists are working on innovative solutions that will aid in capturing the hard to abate emissions before it is too late. Exciting research reveals that ocean alkalinity enhancement, a key climate change mitigation strategy, does not harm phytoplankton, the cornerstone of marine ecosystems. Through meticulous study, we may have uncovered a positive relationship: up to a specific limit, enhancing ocean alkalinity boosts photosynthesis by certain species.
France Van Wambeke, Pascal Conan, Mireille Pujo-Pay, Vincent Taillandier, Olivier Crispi, Alexandra Pavlidou, Sandra Nunige, Morgane Didry, Christophe Salmeron, and Elvira Pulido-Villena
Biogeosciences, 21, 2621–2640, https://doi.org/10.5194/bg-21-2621-2024, https://doi.org/10.5194/bg-21-2621-2024, 2024
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Phosphomonoesterase (PME) and phosphodiesterase (PDE) activities over the epipelagic zone are described in the eastern Mediterranean Sea in winter and autumn. The types of concentration kinetics obtained for PDE (saturation at 50 µM, high Km, high turnover times) compared to those of PME (saturation at 1 µM, low Km, low turnover times) are discussed in regard to the possible inequal distribution of PDE and PME in the size continuum of organic material and accessibility to phosphodiesters.
Allison Hogikyan and Laure Resplandy
EGUsphere, https://doi.org/10.5194/egusphere-2024-1189, https://doi.org/10.5194/egusphere-2024-1189, 2024
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Rising atmospheric CO2 influences ocean carbon chemistry leading to ocean acidification. Global warming introduces spatial patterns in the intensity of ocean acidification. We show that the most prominent spatial patterns are controlled by warming-driven changes in rainfall and evaporation, and not by the direct effect of warming on carbon chemistry and pH. This rainfall/evaporation effect opposes acidification in saltier parts of the ocean and enhances acidification in fresher regions.
Jenny Hieronymus, Magnus Hieronymus, Matthias Gröger, Jörg Schwinger, Raffaele Bernadello, Etienne Tourigny, Valentina Sicardi, Itzel Ruvalcaba Baroni, and Klaus Wyser
Biogeosciences, 21, 2189–2206, https://doi.org/10.5194/bg-21-2189-2024, https://doi.org/10.5194/bg-21-2189-2024, 2024
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The timing of the net primary production annual maxima in the North Atlantic in the period 1750–2100 is investigated using two Earth system models and the high-emissions scenario SSP5-8.5. It is found that, for most of the region, the annual maxima occur progressively earlier, with the most change occurring after the year 2000. Shifts in the seasonality of the primary production may impact the entire ecosystem, which highlights the need for long-term monitoring campaigns in this area.
Medhavi Pandey, Haimanti Biswas, Daniel Birgel, Nicole Burdanowitz, and Birgit Gaye
EGUsphere, https://doi.org/10.5194/egusphere-2024-845, https://doi.org/10.5194/egusphere-2024-845, 2024
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We analyzed the sea surface temperature (SST) proxy and plankton biomarkers in sediments, that accumulate sinking materials signatures from surface waters in the Central Arabian Sea (21°–11° N, 64° E), a tropical basin impacted by monsoon. We noticed a north-south SST gradient and the biological proxies showed more organic matter from larger algae in the north. Smaller algae and zooplankton were high in the south. These trends were related to ocean-atmospheric processes and oxygen availability.
Nicole M. Travis, Colette L. Kelly, and Karen L. Casciotti
Biogeosciences, 21, 1985–2004, https://doi.org/10.5194/bg-21-1985-2024, https://doi.org/10.5194/bg-21-1985-2024, 2024
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We conducted experimental manipulations of light level on microbial communities from the primary nitrite maximum. Overall, while individual microbial processes have different directions and magnitudes in their response to increasing light, the net community response is a decline in nitrite production with increasing light. We conclude that while increased light may decrease net nitrite production, high-light conditions alone do not exclude nitrification from occurring in the surface ocean.
Zoë Rebecca van Kemenade, Zeynep Erdem, Ellen Christine Hopmans, Jaap Smede Sinninghe Damsté, and Darci Rush
Biogeosciences, 21, 1517–1532, https://doi.org/10.5194/bg-21-1517-2024, https://doi.org/10.5194/bg-21-1517-2024, 2024
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The California Current system (CCS) hosts the eastern subtropical North Pacific oxygen minimum zone (ESTNP OMZ). This study shows anaerobic ammonium oxidizing (anammox) bacteria cause a loss of bioavailable nitrogen (N) in the ESTNP OMZ throughout the late Quaternary. Anammox occurred during both glacial and interglacial periods and was driven by the supply of organic matter and changes in ocean currents. These findings may have important consequences for biogeochemical models of the CCS.
Cathy Wimart-Rousseau, Tobias Steinhoff, Birgit Klein, Henry Bittig, and Arne Körtzinger
Biogeosciences, 21, 1191–1211, https://doi.org/10.5194/bg-21-1191-2024, https://doi.org/10.5194/bg-21-1191-2024, 2024
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The marine CO2 system can be measured independently and continuously by BGC-Argo floats since numerous pH sensors have been developed to suit these autonomous measurements platforms. By applying the Argo correction routines to float pH data acquired in the subpolar North Atlantic Ocean, we report the uncertainty and lack of objective criteria associated with the choice of the reference method as well the reference depth for the pH correction.
Sabine Mecking and Kyla Drushka
Biogeosciences, 21, 1117–1133, https://doi.org/10.5194/bg-21-1117-2024, https://doi.org/10.5194/bg-21-1117-2024, 2024
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This study investigates whether northeastern North Pacific oxygen changes may be caused by surface density changes in the northwest as water moves along density horizons from the surface into the subsurface ocean. A correlation is found with a lag that about matches the travel time of water from the northwest to the northeast. Salinity is the main driver causing decadal changes in surface density, whereas salinity and temperature contribute about equally to long-term declining density trends.
Takamitsu Ito, Hernan E. Garcia, Zhankun Wang, Shoshiro Minobe, Matthew C. Long, Just Cebrian, James Reagan, Tim Boyer, Christopher Paver, Courtney Bouchard, Yohei Takano, Seth Bushinsky, Ahron Cervania, and Curtis A. Deutsch
Biogeosciences, 21, 747–759, https://doi.org/10.5194/bg-21-747-2024, https://doi.org/10.5194/bg-21-747-2024, 2024
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This study aims to estimate how much oceanic oxygen has been lost and its uncertainties. One major source of uncertainty comes from the statistical gap-filling methods. Outputs from Earth system models are used to generate synthetic observations where oxygen data are extracted from the model output at the location and time of historical oceanographic cruises. Reconstructed oxygen trend is approximately two-thirds of the true trend.
Robert W. Izett, Katja Fennel, Adam C. Stoer, and David P. Nicholson
Biogeosciences, 21, 13–47, https://doi.org/10.5194/bg-21-13-2024, https://doi.org/10.5194/bg-21-13-2024, 2024
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This paper provides an overview of the capacity to expand the global coverage of marine primary production estimates using autonomous ocean-going instruments, called Biogeochemical-Argo floats. We review existing approaches to quantifying primary production using floats, provide examples of the current implementation of the methods, and offer insights into how they can be better exploited. This paper is timely, given the ongoing expansion of the Biogeochemical-Argo array.
Qian Liu, Yingjie Liu, and Xiaofeng Li
Biogeosciences, 20, 4857–4874, https://doi.org/10.5194/bg-20-4857-2023, https://doi.org/10.5194/bg-20-4857-2023, 2023
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In the Southern Ocean, abundant eddies behave opposite to our expectations. That is, anticyclonic (cyclonic) eddies are cold (warm). By investigating the variations of physical and biochemical parameters in eddies, we find that abnormal eddies have unique and significant effects on modulating the parameters. This study fills a gap in understanding the effects of abnormal eddies on physical and biochemical parameters in the Southern Ocean.
Caroline Ulses, Claude Estournel, Patrick Marsaleix, Karline Soetaert, Marine Fourrier, Laurent Coppola, Dominique Lefèvre, Franck Touratier, Catherine Goyet, Véronique Guglielmi, Fayçal Kessouri, Pierre Testor, and Xavier Durrieu de Madron
Biogeosciences, 20, 4683–4710, https://doi.org/10.5194/bg-20-4683-2023, https://doi.org/10.5194/bg-20-4683-2023, 2023
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Deep convection plays a key role in the circulation, thermodynamics, and biogeochemical cycles in the Mediterranean Sea, considered to be a hotspot of biodiversity and climate change. In this study, we investigate the seasonal and annual budget of dissolved inorganic carbon in the deep-convection area of the northwestern Mediterranean Sea.
Daniela König and Alessandro Tagliabue
Biogeosciences, 20, 4197–4212, https://doi.org/10.5194/bg-20-4197-2023, https://doi.org/10.5194/bg-20-4197-2023, 2023
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Using model simulations, we show that natural and anthropogenic changes in the global climate leave a distinct fingerprint in the isotopic signatures of iron in the surface ocean. We find that these climate effects on iron isotopes are often caused by the redistribution of iron from different external sources to the ocean, due to changes in ocean currents, and by changes in algal growth, which take up iron. Thus, isotopes may help detect climate-induced changes in iron supply and algal uptake.
Chloé Baumas, Robin Fuchs, Marc Garel, Jean-Christophe Poggiale, Laurent Memery, Frédéric A. C. Le Moigne, and Christian Tamburini
Biogeosciences, 20, 4165–4182, https://doi.org/10.5194/bg-20-4165-2023, https://doi.org/10.5194/bg-20-4165-2023, 2023
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Through the sink of particles in the ocean, carbon (C) is exported and sequestered when reaching 1000 m. Attempts to quantify C exported vs. C consumed by heterotrophs have increased. Yet most of the conducted estimations have led to C demands several times higher than C export. The choice of parameters greatly impacts the results. As theses parameters are overlooked, non-accurate values are often used. In this study we show that C budgets can be well balanced when using appropriate values.
Anna Belcher, Sian F. Henley, Katharine Hendry, Marianne Wootton, Lisa Friberg, Ursula Dallman, Tong Wang, Christopher Coath, and Clara Manno
Biogeosciences, 20, 3573–3591, https://doi.org/10.5194/bg-20-3573-2023, https://doi.org/10.5194/bg-20-3573-2023, 2023
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The oceans play a crucial role in the uptake of atmospheric carbon dioxide, particularly the Southern Ocean. The biological pumping of carbon from the surface to the deep ocean is key to this. Using sediment trap samples from the Scotia Sea, we examine biogeochemical fluxes of carbon, nitrogen, and biogenic silica and their stable isotope compositions. We find phytoplankton community structure and physically mediated processes are important controls on particulate fluxes to the deep ocean.
Benoît Pasquier, Mark Holzer, Matthew A. Chamberlain, Richard J. Matear, Nathaniel L. Bindoff, and François W. Primeau
Biogeosciences, 20, 2985–3009, https://doi.org/10.5194/bg-20-2985-2023, https://doi.org/10.5194/bg-20-2985-2023, 2023
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Modeling the ocean's carbon and oxygen cycles accurately is challenging. Parameter optimization improves the fit to observed tracers but can introduce artifacts in the biological pump. Organic-matter production and subsurface remineralization rates adjust to compensate for circulation biases, changing the pathways and timescales with which nutrients return to the surface. Circulation biases can thus strongly alter the system’s response to ecological change, even when parameters are optimized.
Priyanka Banerjee
Biogeosciences, 20, 2613–2643, https://doi.org/10.5194/bg-20-2613-2023, https://doi.org/10.5194/bg-20-2613-2023, 2023
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This study shows that atmospheric deposition is the most important source of iron to the upper northern Indian Ocean for phytoplankton growth. This is followed by iron from continental-shelf sediment. Phytoplankton increase following iron addition is possible only with high background levels of nitrate. Vertical mixing is the most important physical process supplying iron to the upper ocean in this region throughout the year. The importance of ocean currents in supplying iron varies seasonally.
Iris Kriest, Julia Getzlaff, Angela Landolfi, Volkmar Sauerland, Markus Schartau, and Andreas Oschlies
Biogeosciences, 20, 2645–2669, https://doi.org/10.5194/bg-20-2645-2023, https://doi.org/10.5194/bg-20-2645-2023, 2023
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Global biogeochemical ocean models are often subjectively assessed and tuned against observations. We applied different strategies to calibrate a global model against observations. Although the calibrated models show similar tracer distributions at the surface, they differ in global biogeochemical fluxes, especially in global particle flux. Simulated global volume of oxygen minimum zones varies strongly with calibration strategy and over time, rendering its temporal extrapolation difficult.
John C. Tracey, Andrew R. Babbin, Elizabeth Wallace, Xin Sun, Katherine L. DuRussel, Claudia Frey, Donald E. Martocello III, Tyler Tamasi, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 20, 2499–2523, https://doi.org/10.5194/bg-20-2499-2023, https://doi.org/10.5194/bg-20-2499-2023, 2023
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Nitrogen (N) is essential for life; thus, its availability plays a key role in determining marine productivity. Using incubations of seawater spiked with a rare form of N measurable on a mass spectrometer, we quantified microbial pathways that determine marine N availability. The results show that pathways that recycle N have higher rates than those that result in its loss from biomass and present new evidence for anaerobic nitrite oxidation, a process long thought to be strictly aerobic.
Amanda Gerotto, Hongrui Zhang, Renata Hanae Nagai, Heather M. Stoll, Rubens César Lopes Figueira, Chuanlian Liu, and Iván Hernández-Almeida
Biogeosciences, 20, 1725–1739, https://doi.org/10.5194/bg-20-1725-2023, https://doi.org/10.5194/bg-20-1725-2023, 2023
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Based on the analysis of the response of coccolithophores’ morphological attributes in a laboratory dissolution experiment and surface sediment samples from the South China Sea, we proposed that the thickness shape (ks) factor of fossil coccoliths together with the normalized ks variation, which is the ratio of the standard deviation of ks (σ) over the mean ks (σ/ks), is a robust and novel proxy to reconstruct past changes in deep ocean carbon chemistry.
Katherine E. Turner, Doug M. Smith, Anna Katavouta, and Richard G. Williams
Biogeosciences, 20, 1671–1690, https://doi.org/10.5194/bg-20-1671-2023, https://doi.org/10.5194/bg-20-1671-2023, 2023
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We present a new method for reconstructing ocean carbon using climate models and temperature and salinity observations. To test this method, we reconstruct modelled carbon using synthetic observations consistent with current sampling programmes. Sensitivity tests show skill in reconstructing carbon trends and variability within the upper 2000 m. Our results indicate that this method can be used for a new global estimate for ocean carbon content.
Alexandre Mignot, Hervé Claustre, Gianpiero Cossarini, Fabrizio D'Ortenzio, Elodie Gutknecht, Julien Lamouroux, Paolo Lazzari, Coralie Perruche, Stefano Salon, Raphaëlle Sauzède, Vincent Taillandier, and Anna Teruzzi
Biogeosciences, 20, 1405–1422, https://doi.org/10.5194/bg-20-1405-2023, https://doi.org/10.5194/bg-20-1405-2023, 2023
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Numerical models of ocean biogeochemistry are becoming a major tool to detect and predict the impact of climate change on marine resources and monitor ocean health. Here, we demonstrate the use of the global array of BGC-Argo floats for the assessment of biogeochemical models. We first detail the handling of the BGC-Argo data set for model assessment purposes. We then present 23 assessment metrics to quantify the consistency of BGC model simulations with respect to BGC-Argo data.
Alban Planchat, Lester Kwiatkowski, Laurent Bopp, Olivier Torres, James R. Christian, Momme Butenschön, Tomas Lovato, Roland Séférian, Matthew A. Chamberlain, Olivier Aumont, Michio Watanabe, Akitomo Yamamoto, Andrew Yool, Tatiana Ilyina, Hiroyuki Tsujino, Kristen M. Krumhardt, Jörg Schwinger, Jerry Tjiputra, John P. Dunne, and Charles Stock
Biogeosciences, 20, 1195–1257, https://doi.org/10.5194/bg-20-1195-2023, https://doi.org/10.5194/bg-20-1195-2023, 2023
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Ocean alkalinity is critical to the uptake of atmospheric carbon and acidification in surface waters. We review the representation of alkalinity and the associated calcium carbonate cycle in Earth system models. While many parameterizations remain present in the latest generation of models, there is a general improvement in the simulated alkalinity distribution. This improvement is related to an increase in the export of biotic calcium carbonate, which closer resembles observations.
Jérôme Pinti, Tim DeVries, Tommy Norin, Camila Serra-Pompei, Roland Proud, David A. Siegel, Thomas Kiørboe, Colleen M. Petrik, Ken H. Andersen, Andrew S. Brierley, and André W. Visser
Biogeosciences, 20, 997–1009, https://doi.org/10.5194/bg-20-997-2023, https://doi.org/10.5194/bg-20-997-2023, 2023
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Large numbers of marine organisms such as zooplankton and fish perform daily vertical migration between the surface (at night) and the depths (in the daytime). This fascinating migration is important for the carbon cycle, as these organisms actively bring carbon to depths where it is stored away from the atmosphere for a long time. Here, we quantify the contributions of different animals to this carbon drawdown and storage and show that fish are important to the biological carbon pump.
Alastair J. M. Lough, Alessandro Tagliabue, Clément Demasy, Joseph A. Resing, Travis Mellett, Neil J. Wyatt, and Maeve C. Lohan
Biogeosciences, 20, 405–420, https://doi.org/10.5194/bg-20-405-2023, https://doi.org/10.5194/bg-20-405-2023, 2023
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Iron is a key nutrient for ocean primary productivity. Hydrothermal vents are a source of iron to the oceans, but the size of this source is poorly understood. This study examines the variability in iron inputs between hydrothermal vents in different geological settings. The vents studied release different amounts of Fe, resulting in plumes with similar dissolved iron concentrations but different particulate concentrations. This will help to refine modelling of iron-limited ocean productivity.
Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, and Karen L. Casciotti
Biogeosciences, 20, 325–347, https://doi.org/10.5194/bg-20-325-2023, https://doi.org/10.5194/bg-20-325-2023, 2023
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The primary nitrite maximum is a ubiquitous upper ocean feature where nitrite accumulates, but we still do not understand its formation and the co-occurring microbial processes involved. Using correlative methods and rates measurements, we found strong spatial patterns between environmental conditions and depths of the nitrite maxima, but not the maximum concentrations. Nitrification was the dominant source of nitrite, with occasional high nitrite production from phytoplankton near the coast.
Natacha Le Grix, Jakob Zscheischler, Keith B. Rodgers, Ryohei Yamaguchi, and Thomas L. Frölicher
Biogeosciences, 19, 5807–5835, https://doi.org/10.5194/bg-19-5807-2022, https://doi.org/10.5194/bg-19-5807-2022, 2022
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Compound events threaten marine ecosystems. Here, we investigate the potentially harmful combination of marine heatwaves with low phytoplankton productivity. Using satellite-based observations, we show that these compound events are frequent in the low latitudes. We then investigate the drivers of these compound events using Earth system models. The models share similar drivers in the low latitudes but disagree in the high latitudes due to divergent factors limiting phytoplankton production.
Abigale M. Wyatt, Laure Resplandy, and Adrian Marchetti
Biogeosciences, 19, 5689–5705, https://doi.org/10.5194/bg-19-5689-2022, https://doi.org/10.5194/bg-19-5689-2022, 2022
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Marine heat waves (MHWs) are a frequent event in the northeast Pacific, with a large impact on the region's ecosystems. Large phytoplankton in the North Pacific Transition Zone are greatly affected by decreased nutrients, with less of an impact in the Alaskan Gyre. For small phytoplankton, MHWs increase the spring small phytoplankton population in both regions thanks to reduced light limitation. In both zones, this results in a significant decrease in the ratio of large to small phytoplankton.
Margot C. F. Debyser, Laetitia Pichevin, Robyn E. Tuerena, Paul A. Dodd, Antonia Doncila, and Raja S. Ganeshram
Biogeosciences, 19, 5499–5520, https://doi.org/10.5194/bg-19-5499-2022, https://doi.org/10.5194/bg-19-5499-2022, 2022
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We focus on the exchange of key nutrients for algae production between the Arctic and Atlantic oceans through the Fram Strait. We show that the export of dissolved silicon here is controlled by the availability of nitrate which is influenced by denitrification on Arctic shelves. We suggest that any future changes in the river inputs of silica and changes in denitrification due to climate change will impact the amount of silicon exported, with impacts on Atlantic algal productivity and ecology.
Emily J. Zakem, Barbara Bayer, Wei Qin, Alyson E. Santoro, Yao Zhang, and Naomi M. Levine
Biogeosciences, 19, 5401–5418, https://doi.org/10.5194/bg-19-5401-2022, https://doi.org/10.5194/bg-19-5401-2022, 2022
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We use a microbial ecosystem model to quantitatively explain the mechanisms controlling observed relative abundances and nitrification rates of ammonia- and nitrite-oxidizing microorganisms in the ocean. We also estimate how much global carbon fixation can be associated with chemoautotrophic nitrification. Our results improve our understanding of the controls on nitrification, laying the groundwork for more accurate predictions in global climate models.
Zuozhu Wen, Thomas J. Browning, Rongbo Dai, Wenwei Wu, Weiying Li, Xiaohua Hu, Wenfang Lin, Lifang Wang, Xin Liu, Zhimian Cao, Haizheng Hong, and Dalin Shi
Biogeosciences, 19, 5237–5250, https://doi.org/10.5194/bg-19-5237-2022, https://doi.org/10.5194/bg-19-5237-2022, 2022
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Fe and P are key factors controlling the biogeography and activity of marine N2-fixing microorganisms. We found lower abundance and activity of N2 fixers in the northern South China Sea than around the western boundary of the North Pacific, and N2 fixation rates switched from Fe–P co-limitation to P limitation. We hypothesize the Fe supply rates and Fe utilization strategies of each N2 fixer are important in regulating spatial variability in community structure across the study area.
Claudia Eisenring, Sophy E. Oliver, Samar Khatiwala, and Gregory F. de Souza
Biogeosciences, 19, 5079–5106, https://doi.org/10.5194/bg-19-5079-2022, https://doi.org/10.5194/bg-19-5079-2022, 2022
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Given the sparsity of observational constraints on micronutrients such as zinc (Zn), we assess the sensitivities of a framework for objective parameter optimisation in an oceanic Zn cycling model. Our ensemble of optimisations towards synthetic data with varying kinds of uncertainty shows that deficiencies related to model complexity and the choice of the misfit function generally have a greater impact on the retrieval of model Zn uptake behaviour than does the limitation of data coverage.
Yoshikazu Sasai, Sherwood Lan Smith, Eko Siswanto, Hideharu Sasaki, and Masami Nonaka
Biogeosciences, 19, 4865–4882, https://doi.org/10.5194/bg-19-4865-2022, https://doi.org/10.5194/bg-19-4865-2022, 2022
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We have investigated the adaptive response of phytoplankton growth to changing light, nutrients, and temperature over the North Pacific using two physical-biological models. We compare modeled chlorophyll and primary production from an inflexible control model (InFlexPFT), which assumes fixed carbon (C):nitrogen (N):chlorophyll (Chl) ratios, to a recently developed flexible phytoplankton functional type model (FlexPFT), which incorporates photoacclimation and variable C:N:Chl ratios.
Jens Terhaar, Thomas L. Frölicher, and Fortunat Joos
Biogeosciences, 19, 4431–4457, https://doi.org/10.5194/bg-19-4431-2022, https://doi.org/10.5194/bg-19-4431-2022, 2022
Short summary
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Estimates of the ocean sink of anthropogenic carbon vary across various approaches. We show that the global ocean carbon sink can be estimated by three parameters, two of which approximate the ocean ventilation in the Southern Ocean and the North Atlantic, and one of which approximates the chemical capacity of the ocean to take up carbon. With observations of these parameters, we estimate that the global ocean carbon sink is 10 % larger than previously assumed, and we cut uncertainties in half.
Natasha René van Horsten, Hélène Planquette, Géraldine Sarthou, Thomas James Ryan-Keogh, Nolwenn Lemaitre, Thato Nicholas Mtshali, Alakendra Roychoudhury, and Eva Bucciarelli
Biogeosciences, 19, 3209–3224, https://doi.org/10.5194/bg-19-3209-2022, https://doi.org/10.5194/bg-19-3209-2022, 2022
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The remineralisation proxy, barite, was measured along 30°E in the southern Indian Ocean during early austral winter. To our knowledge this is the first reported Southern Ocean winter study. Concentrations throughout the water column were comparable to observations during spring to autumn. By linking satellite primary production to this proxy a possible annual timescale is proposed. These findings also suggest possible carbon remineralisation from satellite data on a basin scale.
Zhibo Shao and Ya-Wei Luo
Biogeosciences, 19, 2939–2952, https://doi.org/10.5194/bg-19-2939-2022, https://doi.org/10.5194/bg-19-2939-2022, 2022
Short summary
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Non-cyanobacterial diazotrophs (NCDs) may be an important player in fixing N2 in the ocean. By conducting meta-analyses, we found that a representative marine NCD phylotype, Gamma A, tends to inhabit ocean environments with high productivity, low iron concentration and high light intensity. It also appears to be more abundant inside cyclonic eddies. Our study suggests a niche differentiation of NCDs from cyanobacterial diazotrophs as the latter prefers low-productivity and high-iron oceans.
Coraline Leseurre, Claire Lo Monaco, Gilles Reverdin, Nicolas Metzl, Jonathan Fin, Claude Mignon, and Léa Benito
Biogeosciences, 19, 2599–2625, https://doi.org/10.5194/bg-19-2599-2022, https://doi.org/10.5194/bg-19-2599-2022, 2022
Short summary
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Decadal trends of fugacity of CO2 (fCO2), total alkalinity (AT), total carbon (CT) and pH in surface waters are investigated in different domains of the southern Indian Ocean (45°S–57°S) from ongoing and station observations regularly conducted in summer over the period 1998–2019. The fCO2 increase and pH decrease are mainly driven by anthropogenic CO2 estimated just below the summer mixed layer, as well as by a warming south of the polar front or in the fertilized waters near Kerguelen Island.
Priscilla Le Mézo, Jérôme Guiet, Kim Scherrer, Daniele Bianchi, and Eric Galbraith
Biogeosciences, 19, 2537–2555, https://doi.org/10.5194/bg-19-2537-2022, https://doi.org/10.5194/bg-19-2537-2022, 2022
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This study quantifies the role of commercially targeted fish biomass in the cycling of three important nutrients (N, P, and Fe), relative to nutrients otherwise available in water and to nutrients required by primary producers, and the impact of fishing. We use a model of commercially targeted fish biomass constrained by fish catch and stock assessment data to assess the contributions of fish at the global scale, at the time of the global peak catch and prior to industrial fishing.
Rebecca Chmiel, Nathan Lanning, Allison Laubach, Jong-Mi Lee, Jessica Fitzsimmons, Mariko Hatta, William Jenkins, Phoebe Lam, Matthew McIlvin, Alessandro Tagliabue, and Mak Saito
Biogeosciences, 19, 2365–2395, https://doi.org/10.5194/bg-19-2365-2022, https://doi.org/10.5194/bg-19-2365-2022, 2022
Short summary
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Dissolved cobalt is present in trace amounts in seawater and is a necessary nutrient for marine microbes. On a transect from the Alaskan coast to Tahiti, we measured seawater concentrations of dissolved cobalt. Here, we describe several interesting features of the Pacific cobalt cycle including cobalt sources along the Alaskan coast and Hawaiian vents, deep-ocean particle formation, cobalt activity in low-oxygen regions, and how our samples compare to a global biogeochemical model’s predictions.
Nicolas Metzl, Claire Lo Monaco, Coraline Leseurre, Céline Ridame, Jonathan Fin, Claude Mignon, Marion Gehlen, and Thi Tuyet Trang Chau
Biogeosciences, 19, 1451–1468, https://doi.org/10.5194/bg-19-1451-2022, https://doi.org/10.5194/bg-19-1451-2022, 2022
Short summary
Short summary
During an oceanographic cruise conducted in January 2020 in the south-western Indian Ocean, we observed very low CO2 concentrations associated with a strong phytoplankton bloom that occurred south-east of Madagascar. This biological event led to a strong regional CO2 ocean sink not previously observed.
Cited articles
Ardyna, M., Lacour, L., Sergi, S., D'Ovidio, F., Sallée, J. B.,
Rembauville, M., Blain, S., Tagliabue, A., Schlitzer, R., Jeandel, C., and
Arrigo, K.R.: Hydrothermal vents trigger massive phytoplankton blooms in the
Southern Ocean, Nat. Commun., 10, 2451,
https://doi.org/10.1038/s41467-019-09973-6, 2019.
Assmy, P., Fernández-Méndez, M., Duarte, P., Meyer, A., Randelhoff,
A., Mundy, C. J., Olsen, L. M., Kauko, H. M., Bailey, A., Chierici, M., and
Cohen, L.: Leads in Arctic pack ice enable early phytoplankton blooms below
snow-covered sea ice, Sci. Rep., 7, 40850,
https://doi.org/10.1038/srep40850, 2017.
Bazzani, E., Lauritano, C., and Saggiomo, M.: Southern Ocean Iron Limitation
of Primary Production between Past Knowledge and Future Projections, Journal
of Marine Science and Engineering, 11, 272,
https://doi.org/10.3390/jmse11020272, 2023.
Biggs, T. E., Huisman, J., and Brussaard, C. P.: Viral lysis modifies seasonal
phytoplankton dynamics and carbon flow in the Southern Ocean, ISME
J., 15, 3615–3622, https://doi.org/10.1038/s41396-021-01033-6,
2021.
Biggs, T. E. G., Rozema, P. D., Evans, C., Timmermans, K. R., Meredith, M. P.,
Pond, D. W., and Brussaard, C. P. D.: Control of Antarctic phytoplankton
community composition and standing stock by light availability, Polar
Biol., 45, 1635–1653, https://doi.org/10.1007/s00300-022-03094-5, 2022.
Blain, S., Sarthou, G., and Laan, P.: Distribution of dissolved iron during
the natural iron-fertilization experiment KEOPS (Kerguelen Plateau, Southern
Ocean), Deep-Sea Res. Pt. II, 55, 594–605,
https://doi.org/10.1016/j.dsr2.2007.12.028, 2008.
Bowie, A. R., Lannuzel, D., Remenyi, T. A., Wagener, T., Lam, P. J., Boyd,
P. W., Guieu, C., Townsend, A. T., and Trull, T. W.: Biogeochemical iron
budgets of the Southern Ocean south of Australia: Decoupling of iron and
nutrient cycles in the subantarctic zone by the summertime supply, Global
Biogeochem. Cy., 23, GB4034, https://doi.org/10.1029/2009GB003500, 2009.
Boyd, P. W. and Abraham, E. R.: Iron-mediated changes in phytoplankton
photosynthetic competence during SOIREE, Deep-Sea Res. Pt. II, 48, 2529–2550,
https://doi.org/10.1016/S0967-0645(01)00007-8, 2001.
Boyd, P. W. and Ellwood, M. J.: The biogeochemical cycle of iron in the
ocean, Nat. Geosci., 3, 675–682, https://doi.org/10.1038/ngeo964, 2010.
Boyd, P. W., Jickells, T., Law, C. S., Blain, S., Boyle, E. A., Buesseler,
K. O., Coale, K. H., Cullen, J. J., de Baar, H. J. W., Follows, M., Harvey, M.,
Lancelot, C., Levasseur, M., Owens, N. P. J., Pollard, R., Rivkin, R. B.,
Sarmiento, J., Schoemann, V., Smetacek, V., Takeda, S., Tsuda, A., Turner,
S., and Watson, A. J.: Mesoscale Iron Enrichment Experiments 1993-2005:
Synthesis and Future Directions, Science, 315, 612–617,
https://doi.org/10.1126/science.1131669, 2007.
Boyd, P. W., Ibisanmi, E., Sander, S. G., Hunter, K. A., and Jackson, G. A.:
Remineralization of upper ocean particles: Implications for iron
biogeochemistry, Limnol. Oceanogr., 55, 1271–1288,
https://doi.org/10.4319/lo.2010.55.3.1271, 2010a.
Boyd, P. W., Strzepek, R., Fu, F., and Hutchins, D. A.: Environmental control
of open-ocean phytoplankton groups: Now and in the future, Limnol. Oceanogr.
55, 1353–1376, https://doi.org/10.4319/lo.2010.55.3.1353, 2010b.
Boyd, P. W., Arrigo, K. R., Strzepek, R., and Van Dijken, G. L.: Mapping
phytoplankton iron utilization: Insights into Southern Ocean supply
mechanisms, J. Geophys. Res.-Ocean, 117, C06009,
https://doi.org/10.1029/2011JC007726, 2012.
Bressac, M., Guieu, C., Ellwood, M. J., Tagliabue, A., Wagener, T.,
Laurenceau-Cornec, E. C., Whitby, H., Sarthou, G., and Boyd, P. W.: Resupply
of mesopelagic dissolved iron controlled by particulate iron composition,
Nat. Geosci., 12, 995–1000, https://doi.org/10.1038/s41561-019-0476-6, 2019.
Brodzik, M. J. and Stewart, J. S.: Near-Real-Time SSM/I-SSMIS EASE-Grid Daily
Global Ice Concentration and Snow Extent, Version 5, Distributed by NASA
National Snow and Ice Data Center Distributed Active Archive Center [data set],
https://doi.org/10.5067/3KB2JPLFPK3R, 2016.
Brown, M., Penta, W. B., Jones, B., and Behrenfeld, M.: The ratio of
single-turnover to multiple-turnover fluorescence varies predictably with
growth rate and cellular chlorophyll in the green alga Dunaliella
tertiolecta, Photosynth. Res., 140, 65–76,
https://doi.org/10.1007/s11120-018-00612-7, 2019.
Browning, T. J., Bouman, H. A., Moore, C. M., Schlosser, C., Tarran, G. A., Woodward, E. M. S., and Henderson, G. M.: Nutrient regimes control phytoplankton ecophysiology in the South Atlantic, Biogeosciences, 11, 463–479, https://doi.org/10.5194/bg-11-463-2014, 2014a.
Browning, T. J., Bouman, H. A., Henderson, G. M., Mather, T. A., Pyle, D. M.,
Schlosser, C., Woodward, E. M. S., and Moore, C. M.: Strong responses of
Southern Ocean phytoplankton communities to volcanic ash, Geophys.
Res. Lett., 41, 2851–2857, https://doi.org/10.1002/2014GL059364,
2014b.
Browning, T. J., Achterberg, E. P., Engel, A., and Mawji, E.: Manganese
co-limitation of phytoplankton growth and major nutrient drawdown in the
Southern Ocean, Nat. Commun., 12, 884, https://doi.org/10.1038/s41467-021-21122-6, 2021.
Chierici, M. and Fransson, A.: Nutrient data (nitrate, phosphate and
silicate) in the eastern Weddell gyre, Kong Haakon VII Hav, and the coast of
Dronning Maud Land in the Atlantic sector of the Southern Ocean in March
2019, Norwegian Marine Data Centre [data set],
https://doi.org/10.21335/NMDC-1503664923, 2020.
Christaki, U., Gueneugues, A., Liu, Y., Blain, S., Catala, P., Colombet, J.,
Debeljak, P., Jardillier, L., Irion, S., Planchon, F., and Sassenhagen, I.:
Seasonal microbial food web dynamics in contrasting Southern Ocean
productivity regimes, Limnol. Oceanogr., 66, 108–122,
https://doi.org/10.1002/lno.11591, 2021.
Coale, K. H., Worsfold, P., and de Baar, H.: Iron age in oceanography, EOS
T. Am. Geophys. Un., 80, 377–382,
https://doi.org/10.1029/EO080i034p00377-02, 1999.
Cochlan, W. P.: Nitrogen uptake in the Southern Ocean, in: Nitrogen in the Marine Environment, edited by: Capone, D. G., Bronk, D. A., Mulholland, M. R., and E. J. Carpenter, 2nd Edn., Academic Press, Elsevier, https://doi.org/10.1016/B978-0-12-372522-6.00012-8, 2008
Cullen, J. J. and Davis, R. F.: The Blank can Make a Big Difference in
Oceanographic Measurements, Limnol. Oceanogr. Bull., 12, 29–35,
https://doi.org/10.1002/lob.200413229, 2003.
Cutter, G., Casciotti, K., Croot, P., Geibert, W., Heimbürger, L.-E.,
Lohan, M., Van De Flierdt, T., and Planquette, H.: Sampling and Sample-handling Protocols for GEOTRACES Cruises, Version 3, August 2017, Toulouse, France, GEOTRACES International Project Office,
https://doi.org/10.25607/OBP-2, 2017.
de Baar, H. J., Buma, A. G., Nolting, R., Cadee, G., Jacques, G., and
Treguer, P.: On iron limitation of the Southern Ocean: experimental
observations in the Weddell and Scotia Seas, Mar. Ecol.-Prog. Ser., 65,
105–122, https://doi.org/10.3354/meps065105, 1990.
de Baar, H. J. W., Boyd, P. W., Coale, K. H., Landry, M. R., Tsuda, A., Assmy,
P., Bakker, D. C. E., Bozec, Y., Barber, R. T., Brzezinski, M. A., Buesseler,
K. O., Boyé, M., Croot, P. L., Gervais, F., Gorbunov, M. Y., Harrison,
P. J., Hiscock, W. T., Laan, P., Lancelot, C., Law, C. S., Levasseur, M.,
Marchetti, A., Millero, F. J., Nishioka, J., Nojiri, Y., van Oijen, T.,
Riebesell, U., Rijkenberg, M. J. A., Saito, H., Takeda, S., Timmermans, K. R.,
Veldhuis, M. J. W., Waite, A. M., and Wong, C. S.: Synthesis of iron
fertilization experiments: From the iron age in the age of enlightenment, J.
Geophys. Res.-Ocean, 110, 1–24, https://doi.org/10.1029/2004JC002601,
2005.
Deppeler, S. L. and Davidson, A. T.: Southern Ocean Phytoplankton in a
Changing Climate, Front. Mar. Sci. 4, 40,
https://doi.org/10.3389/fmars.2017.00040, 2017.
Diaz, J. M. and Plummer, S.: Production of extracellular reactive oxygen
species by phytoplankton: past and future directions, J Plankton Res., 40,
655–666, https://doi.org/10.1093/plankt/fby039, 2018.
Ellwood, M. J., Boyd, P. W., and Sutton, P.: Winter-time dissolved iron and
nutrient distributions in the Subantarctic Zone from 40–52S; 155–160E,
Geophys. Res. Lett., 35, L11604, https://doi.org/10.1029/2008GL033699,
2008.
Evans, C. and Brussaard, C. P. D.: Regional variation in lytic and lysogenic
viral infection in the Southern Ocean and its contribution to biogeochemical
cycling, Appl. Environ. Microb., 78, 6741–6748,
https://doi.org/10.1128/AEM.01388-12, 2012.
Fourquez, M., Obernosterer, I., Davies, D. M., Trull, T. W., and Blain, S.: Microbial iron uptake in the naturally fertilized waters in the vicinity of the Kerguelen Islands: phytoplankton–bacteria interactions, Biogeosciences, 12, 1893–1906, https://doi.org/10.5194/bg-12-1893-2015, 2015.
Geider, R. J.: Quantitative phytoplankton physiology: implications for
primary production and phytoplankton growth, ICES Mar. Sci. Symp., 197,
52–62, 1993.
Geider, R. J. and La Roche, J.: The role of iron in phytoplankton
photosynthesis, and the potential for iron-limitation of primary
productivity in the sea, Photosynth. Res., 39, 275–301,
https://doi.org/10.1007/BF00014588, 1994.
Grasshoff, K., Kremling, K., and Ehrhardt, M.: Methods of Seawater Analysis,
3rd Edn., Hoboken, NJ, Wiley-VCH, ISBN 978-3-527-61399-1, 2009.
Gundersen, K., Møgster, J. S., Lien, V. S., Ershova, E., Lunde, L. F.,
Arnesen, H., and Olsen, A. K.: Thirty Years of Nutrient Biogeochemistry in
the Barents Sea and the adjoining Arctic Ocean, 1990–2019, Sci. Data,
9, 649, https://doi.org/10.1038/s41597-022-01781-w, 2022.
Hauck, J., Völker, C., Wolf-Gladrow, D. A., Laufkötter, C., Vogt, M.,
Aumont, O., Bopp, L., Buitenhuis, E. T., Doney, S. C., Dunne, J., and Gruber,
N.: On the Southern Ocean CO2 uptake and the role of the biological carbon
pump in the 21st century, Global Biogeochem. Cy., 29, 1451–1470,
https://doi.org/10.1002/2015GB005140, 2015.
Hawco, N. J., Tagliabue, A., and Twining, B. S.: Manganese Limitation of
Phytoplankton Physiology and Productivity in the Southern Ocean, Global
Biogeochem. Cy., 36, e2022GB007382,
https://doi.org/10.1029/2022GB007382, 2022.
Hinz, D. J., Nielsdóttir, M. C., Korb, R. E., Whitehouse, M. J., Poulton,
A. J., Moore, C. M., Achterberg, E. P., and Bibby, T. S.: Responses of
microplankton community structure to iron addition in the Scotia Sea, Deep-Res. Pt. II, 59–60, 36–46,
https://doi.org/10.1016/j.dsr2.2011.08.006, 2012.
Hiscock, M. R., Lance, V. P., Apprill, A. M., Bidigare, R. R., Johnson, Z. I.,
Mitchell, B. G., Smith, W. O., and Barber, R. T.: Photosynthetic maximum
quantum yield increases are an essential component of the Southern Ocean
phytoplankton response to iron, P. Natl. Acad. Sci. USA, 105, 4775–4780,
https://doi.org/10.1073/pnas.0705006105, 2008.
Holm-Hansen, O. and Riemann, B.: Chlorophyll a Determination: Improvements in Methodology, Oikos, 30, 3, 438–447, https://doi.org/10.2307/3543338, 1978.
Hughes, D. J., Campbell, D. A., Doblin, M. A., Kromkamp, J. C., Lawrenz, E.,
Moore, C. M., Oxborough, K., Prášil, O., Ralph, P. J., Alvarez, M. F.,
and Suggett, D. J.: Roadmaps and Detours: Active Chlorophyll-a Assessments
of Primary Productivity Across Marine and Freshwater Systems, Environ. Sci.
Technol., 52, 12039–12054, https://doi.org/10.1021/acs.est.8b03488, 2018.
Kauko, H. M., Moreau, S., and Hattermann, T.: Southern Ocean Ecosystem
cruise 2019 vertical in situ chlorophyll a profiles, Norwegian Polar
Institute [data set], https://doi.org/10.21334/npolar.2021.5e510f85, 2020.
Kauko, H. M., Hattermann, T., Ryan-Keogh, T., Singh, A., de Steur, L.,
Fransson, A., Chierici, M., Falkenhaug, T., Hallfredsson, E. H., Bratbak, G.,
and Tsagaraki, T.: Phenology and environmental control of phytoplankton
blooms in the Kong Håkon VII Hav in the Southern Ocean, Front. Mar. Sci.,
8, 623856, https://doi.org/10.3389/fmars.2021.623856, 2021.
Kauko, H. M., Moreau, S., Rózañska, M., and Wiktor, J. M.: Southern
Ocean Ecosystem cruise 2019 phytoplankton taxonomy and abundance, Norwegian
Polar Institute [data set], https://doi.org/10.21334/npolar.2022.283e500c,
2022a.
Kauko, H. M., Assmy, P., Peeken, I., Różańska-Pluta, M., Wiktor, J. M., Bratbak, G., Singh, A., Ryan-Keogh, T. J., and Moreau, S.: First phytoplankton community assessment of the Kong Håkon VII Hav, Southern Ocean, during austral autumn, Biogeosciences, 19, 5449–5482, https://doi.org/10.5194/bg-19-5449-2022, 2022b.
Khatiwala, S., Primeau, F., and Hall, T.: Reconstruction of the history of
anthropogenic CO2 concentrations in the ocean, Nature, 462, 346–349,
https://doi.org/10.1038/nature08526, 2009.
Kirk, J. T. O.: Light and photosynthesis in aquatic ecosystems, Cambridge
University Press, https://doi.org/10.1017/CBO9780511623370, 1994.
Klunder, M. B., Laan, P., Middag, R., De Baar, H. J. W., and van Ooijen, J. C.:
Dissolved iron in the Southern Ocean (Atlantic sector), Deep-Sea Res. Pt. II, 58, 2678–2694,
https://doi.org/10.1016/j.dsr2.2010.10.042, 2011.
Kolber, Z., Zehr, J., and Falkowski, P.: Effects of Growth Irradiance and
Nitrogen Limitation on Photosynthetic Energy Conversion in Photosystem II.
Plant Physiol., 88, 923–929, https://doi.org/10.1104/pp.88.3.923, 1988.
Kolber, Z. S., Barber, R. T., Coale, K. H., Fitzwateri, S. E., Greene, R. M.,
Johnson, K. S., Lindley, S., and Falkowski, P. G.: Iron limitation of
phytoplankton photosynthesis in the equatorial Pacific Ocean, Nature, 371,
145–149, https://doi.org/10.1038/371145a0, 1994.
Kolber, Z. S., Prášil, O., and Falkowski, P. G.: Measurements of
variable chlorophyll fluorescence using fast repetition rate techniques:
defining methodology and experimental protocols, BBA-Bioenergetics, 1367, 88–106, https://doi.org/10.1016/S0005-2728(98)00135-2,
1998.
Lancelot, C., Mathot, S., Veth, C., and de Baar, H.: Factors controlling
phytoplankton ice-edge blooms in the marginal ice-zone of the northwestern
Weddell Sea during sea ice retreat 1988: field observations and mathematical
modelling, Polar Biol., 13, 377–387, https://doi.org/10.1007/BF01681979,
1993.
Lannuzel, D., Schoemann, V., de Jong, J., Chou, L., Delille, B., Becquevort,
S., and Tison, J. L.: Iron study during a time series in the western Weddell
pack ice, Mar. Chem., 108, 85–95,
https://doi.org/10.1016/j.marchem.2007.10.006, 2008.
Lannuzel, D., Vancoppenolle, M., van Der Merwe, P., De Jong, J., Meiners,
K. M., Grotti, M., Nishioka, J., and Schoemann, V.: Iron in sea ice: Review
and new insightsIron in sea ice: Review and new insights, Elementa, 4, 000130, https://doi.org/10.12952/journal.elementa.000130,
2016.
Lindsey, R. and Scott, M.: What are Phytoplankton?, https://earthobservatory.nasa.gov/features/Phytoplankton
(last access: 20 July 2023), 2010.
Lis, H., Shaked, Y., Kranzler, C., Keren, N., and Morel, F. M.: Iron
bioavailability to phytoplankton: an empirical approach, ISME J.,
9, 1003–1013, https://doi.org/10.1038/ismej.2014.199, 2015.
Lucas, M., Seeyave, S., Sanders, R., Moore, C. M., Williamson, R., and
Stinchcombe, M.: Nitrogen uptake responses to a naturally Fe-fertilised
phytoplankton bloom during the 2004/2005 CROZEX study, Deep-Sea Res. Pt. II,
54, 2138–2173,
https://doi.org/10.1016/j.dsr2.2007.06.017, 2007.
Lutjeharms, J. R. E., Walters, N. M., and Allanson, B. R.: Oceanic frontal
systems and biological enhancement, in: Antarctic Nutrient Cycles and Food
Webs, Springer Berlin Heidelberg, 11–21,
https://doi.org/10.1007/978-3-642-82275-9_3, 1985.
Mahowald, N. M., Baker, A. R., Bergametti, G., Brooks, N., Duce, R. A.,
Jickells, T. D., Kubilay, N., Prospero, J. M., and Tegen, I.: Atmospheric
global dust cycle and iron inputs to the ocean, Global Biogeochem. Cy.,
19, GB4025, https://doi.org/10.1029/2004GB002402, 2005.
Martin, J. H. and Fitzwater, S. E.: Iron deficiency limits phytoplankton
growth in the north-east Pacific subarctic, Nature, 331, 341–343,
https://doi.org/10.1038/331341a0, 1988.
Martin, J. H., Gordon, R. M., and Fitzwater, S. E.: Iron in Antarctic waters.
Nature, 345, 156–158, https://doi.org/10.1038/345156a0, 1990.
Martin, J. H., Gordon, M., and Fitzwater, S. E.: The case for iron, Limnol.
Oceanogr., 36, 1793–1802, https://doi.org/10.4319/lo.1991.36.8.1793, 1991.
Millard, R. C., Owens, W. B., and Fofonoff, N. P.: On the calculation of the
Brunt-Väisäla frequency, Deep-Sea Res. Pt. A,
37, 167–181, https://doi.org/10.1016/0198-0149(90)90035-T, 1990.
Milligan, A. J. and Harrison, P. J.: Effects of non-steady-state iron
limitation on nitrogen assimilatory enzymes in the marine diatom
thalassiosira weissflogii (BACILLARIOPHYCEAE), J. Phycol., 36, 78–86,
https://doi.org/10.1046/j.1529-8817.2000.99013.x, 2000.
Mitchell, B. G., Brody, E. A., Holm-Hansen, O., McClain, C., and Bishop, J.:
Light limitation of phytoplankton biomass and macronutrient utilization in
the Southern Ocean, Limnol. Oceanogr., 36, 1662–1677,
https://doi.org/10.4319/lo.1991.36.8.1662, 1991.
Moore, C. M., Hickman, A. E., Poulton, A. J., Seeyave, S., and Lucas, M. I.:
Iron–light interactions during the CROZet natural iron bloom and EXport
experiment (CROZEX): II – Taxonomic responses and elemental stoichiometry,
Deep-Sea Res. Pt. II, 54, 2066–2084,
https://doi.org/10.1016/j.dsr2.2007.06.015, 2007a.
Moore, C. M., Seeyave, S., Hickman, A. E., Allen, J. T., Lucas, M. I.,
Planquette, H., Pollard, R. T., and Poulton, A. J.: Iron-light interactions
during the CROZet natural iron bloom and EXport experiment (CROZEX) I:
Phytoplankton growth and photophysiology, Deep-Sea Res. Pt. II, 54, 2045–2065, https://doi.org/10.1016/j.dsr2.2007.06.011, 2007b.
Moore, C. M., Mills, M. M., Arrigo, K. R., Berman-Frank, I., Bopp, L., Boyd,
P. W., Galbraith, E. D., Geider, R. J., Guieu, C., Jaccard, S. L., Jickells,
T. D., La Roche, J., Lenton, T. M., Mahowald, N. M., Marañón, E.,
Marinov, I., Moore, J. K., Nakatsuka, T., Oschlies, A., Saito, M. A.,
Thingstad, T. F., Tsuda, A., and Ulloa, O.: Processes and patterns of oceanic
nutrient limitation, Nat. Geosci., 6, 701–710,
https://doi.org/10.1038/ngeo1765, 2013.
Moore, J. K. and Abbott, M. R.: Surface chlorophyll concentrations in
relation to the Antarctic Polar Front: seasonal and spatial patterns from
satellite observations, J. Marine Syst., 37, 69–86,
https://doi.org/10.1016/S0924-7963(02)00196-3, 2002.
Moore, J. K., Doney, S. C., Glover, D. M., and Fung, I. Y.: Iron cycling and
nutrient-limitation patterns in surface waters of the World Ocean, Deep-Sea
Res. Pt. II, 49, 463–507, https://doi.org/10.1016/S0967-0645(01)00109-6, 2001.
Moreau, S., Boyd, P. W., and Strutton, P. G.: Remote assessment of the fate of
phytoplankton in the Southern Ocean sea-ice zone, Nat. Commun., 11, 1–9,
https://doi.org/10.1038/s41467-020-16931-0, 2020.
Moreau, S., Hattermann, T., de Steur, L., Kauko, H. M., Ahonen, H., Ardelan,
M. V., Assmy, P., Chierici, M., Descamps, S., Dinter, T., Falkenhaug, T.,
Fransson, A., Grønningsæter, E., Hallfredsson, E. H., Huhn, O.,
Lebrun, A., Lowther, A., Lübcker, N., Monteiro, P. M. S., Peeken, I.,
Roychoudhury, A., Różańska, M., Ryan-Keogh, T. J., Sanchez, N.,
Singh, A., Simonsen, J.-H., Steiger, N., Thomalla, S. J., van Tonder, A.,
Wiktor, J. M., and Steen, H.: Wind-driven upwelling of iron sustains dense blooms
and food webs in the eastern Weddell Gyre, Nat. Commun., 14, 1303,
https://doi.org/10.1038/s41467-023-36992-1, 2023.
Mtshali, T. N., van Horsten, N. R., Thomalla, S. J., Ryan-Keogh, T. J.,
Nicholson, S. A., Roychoudhury, A. N., Bucciarelli, E., Sarthou, G.,
Tagliabue, A., and Monteiro, P. M. S.: Seasonal Depletion of the Dissolved
Iron Reservoirs in the Sub-Antarctic Zone of the Southern Atlantic Ocean,
Geophys. Res. Lett., 46, 4386–4395, https://doi.org/10.1029/2018GL081355,
2019.
National Geophysical Data Center/NESDIS/NOAA/U.S. Department of Commerce: ETOPO1, Global 1 Arc-minute Ocean Depth and Land Elevation from the US National Geophysical Data Center (NGDC), Research Data Archive at the National Center for Atmospheric Research, Computational and Information Systems Laboratory, https://doi.org/10.5065/D69Z92Z5, 2011.
Nicholson, S. A., Lévy, M., Jouanno, J., Capet, X., Swart, S., and
Monteiro, P. M. S.: Iron Supply Pathways Between the Surface and Subsurface
Waters of the Southern Ocean: From Winter Entrainment to Summer Storms,
Geophys. Res. Lett., 46, 14567–14575, https://doi.org/10.1029/2019GL084657,
2019.
Pollard, R., Sanders, R., Lucas, M., and Statham, P.: The Crozet Natural
Iron Bloom and Export Experiment (CROZEX), Deep-Sea Res. Pt. II, 54, 1905–1914, https://doi.org/10.1016/j.dsr2.2007.07.023, 2007.
Price, N. M., Ahner, B. A., and Morel, F. M.: The equatorial Pacific Ocean:
Grazer-controlled phytoplankton populations in an iron-limited ecosystem 1,
Limnol. Oceanogr., 39, 520–534, https://doi.org/10.4319/LO.1994.39.3.0520,
1994.
Racault, M. F., Sathyendranath, S., and Platt, T.: Impact of missing data on
the estimation of ecological indicators from satellite ocean-colour
time-series, Remote Sens. Environ., 152, 15–28,
https://doi.org/10.1016/j.rse.2014.05.016, 2014.
Raven, J. A.: Predictions of Mn and Fe use efficiencies of phototrophic
growth as a function of light availability for growth and of C assimilation
pathway, New Phytol., 116, 1–18,
https://doi.org/10.1111/j.1469-8137.1990.tb00505.x, 1990.
Raven, J. A., Evans, M. C. W., and Korb, R. E.: The role of trace metals in
photosynthetic electron transport in O-2-evolving organisms, Photosynth.
Res., 60, 111–149, https://doi.org/10.1023/a:1006282714942, 1999.
Richert, I., Yager, P. L., Dinasquet, J., Logares, R., Riemann, L.,
Wendeberg, A., Bertilsson, S., and Scofield, D. G.: Summer comes to the
Southern Ocean: how phytoplankton shape bacterioplankton communities far
into the deep dark sea, Ecosphere, 10, e02641,
https://doi.org/10.1002/ecs2.2641, 2019.
Roháček, K.: Chlorophyll fluorescence parameters: The definitions,
photosynthetic meaning, and mutual relationships, Photosynthetica, 40,
13–29, https://doi.org/10.1023/A:1020125719386, 2002.
Ryan-Keogh, T. J.: Understanding the role of chlorophyll fluorescence in
nutrient stress, Doctoral dissertation, University of Southampton,
http://eprints.soton.ac.uk/id/eprint/362003 (last access: 1 March 2022), 2014.
Ryan-Keogh, T. J. and Robinson, C.: Phytoplankton Photophysiology Utilities:
A Python Toolbox for the Standardization of Processing Active Chlorophyll-a
Fluorescence Data, Front. Mar. Sci. Aquat. Physiol., 8, 525414,
https://doi.org/10.3389/fmars.2021.525414, 2021.
Ryan-Keogh, T. J., Macey, A. I., Nielsdóttir, M. C., Lucas, M. I.,
Steigenberger, S. S., Stinchcombe, M. C., Achterberg, E. P., Bibby, T. S., and
Moore, C. M.: Spatial and temporal development of phytoplankton iron stress
in relation to bloom dynamics in the high-latitude North Atlantic Ocean,
Limnol. Oceanogr., 58, 533–545, https://doi.org/10.4319/lo.2013.58.2.0533,
2013.
Ryan-Keogh, T. J., DeLizo, L. M., Smith, W. O., Sedwick, P. N., McGillicuddy,
D. J., Moore, C. M., and Bibby, T. S.: Temporal progression of
photosynthetic-strategy in phytoplankton in the Ross Sea, Antarctica, J.
Marine Syst., 166, 87–96, https://doi.org/10.1016/j.jmarsys.2016.08.014,
2017.
Ryan-Keogh, T. J., Thomalla, S. J., Mtshali, T. N., van Horsten, N. R., and Little, H. J.: Seasonal development of iron limitation in the sub-Antarctic zone, Biogeosciences, 15, 4647–4660, https://doi.org/10.5194/bg-15-4647-2018, 2018.
Ryan-Keogh, T. J., Thomalla, S. J., Monteiro, P. M., and Tagliabue, A.:
Multidecadal trend of increasing iron stress in Southern Ocean
phytoplankton, Science, 379, 834–840,
https://doi.org/10.1126/science.abl5237, 2023.
Salgado-Hernanz, P. M., Racault, M. F., Font-Muñoz, J. S., and
Basterretxea, G.: Trends in phytoplankton phenology in the Mediterranean Sea
based on ocean-colour remote sensing, Remote Sens. Environ., 221, 50–64,
https://doi.org/10.1016/j.rse.2018.10.036, 2019.
Samanta, S., Cloete, R., Loock, J., Rossouw, R., and Roychoudhury, A. N.:
Determination of trace metal (Mn, Fe, Ni, Cu, Zn, Co, Cd and Pb)
concentrations in seawater using single quadrupole ICP-MS: A comparison
between offline and online preconcentration setups, Minerals 11, 1289,
https://doi.org/10.3390/min11111289, 2021.
Sathyendranath, S., Brewin, R. J., Brockmann, C., Brotas, V., Calton, B.,
Chuprin, A., Cipollini, P., Couto, A. B., Dingle, J., Doerffer, R., and
Donlon, C.: An ocean-colour time series for use in climate studies: the
experience of the ocean-colour climate change initiative (OC-CCI), Sensors,
19, 4285, https://doi.org/10.3390/s19194285, 2019.
Schuback, N., Flecken, M., Maldonado, M. T., and Tortell, P. D.: Diurnal variation in the coupling of photosynthetic electron transport and carbon fixation in iron-limited phytoplankton in the NE subarctic Pacific, Biogeosciences, 13, 1019–1035, https://doi.org/10.5194/bg-13-1019-2016, 2016.
Schuback, N., Tortell, P. D., Berman-Frank, I., Campbell, D. A., Ciotti, A.,
Courtecuisse, E., Erickson, Z. K., Fujiki, T., Halsey, K., Hickman, A. E., and
Huot, Y.: Single-turnover variable chlorophyll fluorescence as a tool for
assessing phytoplankton photosynthesis and primary productivity:
opportunities, caveats and recommendations, Front. Mar. Sci., 8,
690607, https://doi.org/10.3389/fmars.2021.690607, 2021.
Sedwick, P. N., DiTullio, G. R., Hutchins, D. A., Boyd, P. W., Griffiths, F. B.,
Crossley, A. C., Trull, T. W., and Quéguiner, B.: Limitation of algal
growth by iron deficiency in the Australian Subantarctic region, Geophys.
Res. Lett., 26, 2865–2868, https://doi.org/10.1029/1998GL002284,
1999.
Sedwick, P. N., Bowie, A. R., and Trull, T. W.: Dissolved iron in the
Australian sector of the Southern Ocean (CLIVAR SR3 section): meridional and
seasonal trends, Deep-Sea Res. Pt. I, 55, 911–925,
https://doi.org/10.1016/j.dsr.2008.03.011, 2008.
Singh, A., Fietz, S., Thomalla, S. J., Sanchez, N., Ardelan, M. V., Moreau, S., Kauko, H. M., Fransson, A., Chierici, M., Samanta, S., Mtshali, T. N., Roychoudhury, A. N., and Ryan‐Keogh, T. J.: Photophysiological response of autumn phytoplankton in the Antarctic Sea-Ice Zone, Zenodo [data set], https://doi.org/10.5281/zenodo.6322943, 2022.
Smith, W. O., Dinniman, M. S., Tozzi, S., DiTullio, G. R., Mangoni, O., Modigh,
M., and Saggiomo, V.: Phytoplankton photosynthetic pigments in the Ross Sea:
Patterns and relationships among functional groups, J. Marine Syst., 82,
177–185, https://doi.org/10.1016/j.jmarsys.2010.04.014, 2010.
Soppa, M. A., Völker, C., and Bracher, A.: Diatom phenology in the
Southern Ocean: mean patterns, trends and the role of climate oscillations,
Remote Sens., 8, 420, https://doi.org/10.3390/rs8050420, 2016.
Strzepek, R. F. and Harrison, P. J.: Photosynthetic architecture differs in
coastal and oceanic diatoms, Nature, 431, 689–692,
https://doi.org/10.1038/nature02954, 2004.
Strzepek, R. F., Maldonado, M. T., Hunter, K. A., Frew, R. D., and Boyd, P. W.:
Adaptive strategies by Southern Ocean phytoplankton to lessen iron
limitation: Uptake of organically complexed iron and reduced cellular iron
requirements, Limnol. Oceanogr., 56, 1983–2002,
https://doi.org/10.4319/lo.2011.56.6.1983, 2011.
Strzepek, R. F., Hunter, K. A., Frew, R. D., Harrison, P. J., and Boyd, P. W.:
Iron-light interactions differ in Southern Ocean phytoplankton, Limnol.
Oceanogr., 57, 1182–1200, https://doi.org/10.4319/lo.2012.57.4.1182, 2012.
Strzepek, R. F., Boyd, P. W., and Sunda, W. G.: Photosynthetic adaptation to
low iron, light, and temperature in Southern Ocean phytoplankton, P.
Natl. Acad. Sci. USA, 116, 4388–4393, https://doi.org/10.1073/pnas.1810886116,
2019.
Suggett, D., Kraay, G., Holligan, P., Davey, M., Aiken, J., and Geider, R.:
Assessment of photosynthesis in a spring cyanobacterial bloom by use of a
fast repetition rate fluorometer, Limnol. Oceanogr., 46, 802–810,
https://doi.org/10.4319/lo.2001.46.4.0802, 2001.
Suggett, D. J., Moore, C. M., Hickman, A. E., and Geider, R. J.: Interpretation
of fast repetition rate (FRR) fluorescence: Signatures of phytoplankton
community structure versus physiological state, Mar. Ecol.-Prog. Ser., 376,
1–19, https://doi.org/10.3354/meps07830, 2009.
Sunda, W. G.: Trace metal interactions with marine phytoplankton, Biol.
Oceanogr., 6, 411–442, 1989.
Sunda, W. G. and Huntsman, S. A.: Iron uptake and growth limitation in
oceanic and coastal phytoplankton, Mar. Chem., 50, 189–206,
https://doi.org/10.1016/0304-4203(95)00035-P, 1995.
Swart, S., Thomalla, S. J., and Monteiro, P. M. S.: The seasonal cycle of mixed
layer dynamics and phytoplankton biomass in the Sub-Antarctic Zone: A
high-resolution glider experiment, J. Marine Syst., 147, 103–115,
https://doi.org/10.1016/j.jmarsys.2014.06.002, 2015.
Tagliabue, A., Sallée, J. B., Bowie, A. R., Lévy, M., Swart, S., and
Boyd, P. W.: Surface-water iron supplies in the Southern Ocean sustained by
deep winter mixing, Nat. Geosci., 7, 314–320,
https://doi.org/10.1038/ngeo2101, 2014.
Tagliabue, A., Bowie, A. R., Boyd, P. W., Buck, K. N., Johnson, K. S., and
Saito, M. A.: The integral role of iron in ocean biogeochemistry, Nature, 543,
51–59, https://doi.org/10.1038/nature21058, 2017.
Takahashi, T., Sutherland, S. C., Sweeney, C., Poisson, A., Metzl, N.,
Tilbrook, B., Bates, N., Wanninkhof, R., Feely, R. A., Sabine, C., Olafsson,
J., and Yukihiro, N.: Global sea–air CO2 flux based on climatological
surface ocean pCO2, and seasonal biological and temperature effects, Deep-Sea Res. Pt. II, 49, 1601–1622,
https://doi.org/10.1016/S0967-0645(02)00003-6, 2002.
Takahashi, T., Sutherland, S. C., Wanninkhof, R., Sweeney, C., Feely, R. A.,
Chipman, D. W., Hales, B., Friederich, G., Chavez, F., Sabine, C., and
Watson, A.: Climatological mean and decadal change in surface ocean pCO2,
and net sea–air CO2 flux over the global oceans, Deep-Sea Res. Pt. II, 56, 554–577, https://doi.org/10.1016/j.dsr2.2008.12.009,
2009.
Taylor, M. H., Losch, M., and Bracher, A.: On the drivers of phytoplankton blooms
in the Antarctic marginal ice zone: A modeling approach, J. Geophys. Res.-Ocean, 118, 63–75, https://doi.org/10.1029/2012JC008418, 2013.
Thomalla, S. J., Fauchereau, N., Swart, S., and Monteiro, P. M. S.: Regional scale characteristics of the seasonal cycle of chlorophyll in the Southern Ocean, Biogeosciences, 8, 2849–2866, https://doi.org/10.5194/bg-8-2849-2011, 2011.
Trimborn, S., Thoms, S., Bischof, K., and Beszteri, S.: Susceptibility of
two Southern Ocean phytoplankton key species to iron limitation and high
light, Front. Mar. Sci., 6, 167, https://doi.org/10.3389/fmars.2019.00167, 2019.
Van Oijen, T., Van Leeuwe, M. A., Granum, E., Weissing, F. J., Bellerby,
R. G. J., Gieskes, W. W. C., and de Baar, H. J. W.: Light rather than iron
controls photosynthate production and allocation in Southern Ocean
phytoplankton populations during austral autumn, J. Plankton Res., 26,
885–900, https://doi.org/10.1093/plankt/fbh088, 2004.
Viljoen, J. J., Philibert, R., Van Horsten, N., Mtshali, T., Roychoudhury,
A. N., Thomalla, S., and Fietz, S.: Phytoplankton response in growth,
photophysiology and community structure to iron and light in the Polar
Frontal Zone and Antarctic waters, Deep-Sea Res. Pt. I,
141, 118–129, https://doi.org/10.2495/EEIA100071, 2018.
Vink, S. and Measures, C. I.: The role of dust deposition in determining
surface water distributions of Al and Fe in the South West Atlantic, Deep-Sea Res. Pt. II, 48, 2787–2809,
https://doi.org/10.1016/S0967-0645(01)00018-2, 2001.
Wu, M., McCain, J. S. P., Rowland, E., Middag, R., Sandgren, M., Allen, A. E.,
and Bertrand, E. M.: Manganese and iron deficiency in Southern Ocean
Phaeocystis antarctica populations revealed through taxon-specific protein
indicators, Nat. Commun., 10, 3582,
https://doi.org/10.1038/s41467-019-11426-z, 2019.
Yoon, J.-E., Yoo, K.-C., Macdonald, A. M., Yoon, H.-I., Park, K.-T., Yang, E. J., Kim, H.-C., Lee, J. I., Lee, M. K., Jung, J., Park, J., Lee, J., Kim, S., Kim, S.-S., Kim, K., and Kim, I.-N.: Reviews and syntheses: Ocean iron fertilization experiments – past, present, and future looking to a future Korean Iron Fertilization Experiment in the Southern Ocean (KIFES) project, Biogeosciences, 15, 5847–5889, https://doi.org/10.5194/bg-15-5847-2018, 2018.
Short summary
Despite the scarcity of iron in the Southern Ocean, seasonal blooms occur due to changes in nutrient and light availability. Surprisingly, during an autumn bloom in the Antarctic sea-ice zone, the results from incubation experiments showed no significant photophysiological response of phytoplankton to iron addition. This suggests that ambient iron concentrations were sufficient, challenging the notion of iron deficiency in the Southern Ocean through extended iron-replete post-bloom conditions.
Despite the scarcity of iron in the Southern Ocean, seasonal blooms occur due to changes in...
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