Articles | Volume 19, issue 13
https://doi.org/10.5194/bg-19-3209-2022
© Author(s) 2022. 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-19-3209-2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
11 Jul 2022
Research article |
| 11 Jul 2022
| 11 Jul 2022
Early winter barium excess in the southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise)
Natasha René van Horsten
CORRESPONDING AUTHOR
Univ Brest, CNRS, IRD, Ifremer, LEMAR, 29280 Plouzane, France
SOCCO, CSIR, Lower Hope Road, Cape Town, 7700, South Africa
Department of Earth Sciences, TracEx, Stellenbosch University,
Stellenbosch, 7600, South Africa
Hélène Planquette
Univ Brest, CNRS, IRD, Ifremer, LEMAR, 29280 Plouzane, France
Géraldine Sarthou
Univ Brest, CNRS, IRD, Ifremer, LEMAR, 29280 Plouzane, France
Thomas James Ryan-Keogh
SOCCO, CSIR, Lower Hope Road, Cape Town, 7700, South Africa
Nolwenn Lemaitre
Department of Earth Sciences, Institute of Geochemistry and Petrology,
ETH Zurich, Zurich, Switzerland
Thato Nicholas Mtshali
Department of Forestry, Fisheries and Environment, Oceans and Coasts,
Foretrust Building, Martin Hammerschlag Way, Cape Town, 8001, South Africa
Alakendra Roychoudhury
Department of Earth Sciences, TracEx, Stellenbosch University,
Stellenbosch, 7600, South Africa
Eva Bucciarelli
CORRESPONDING AUTHOR
Univ Brest, CNRS, IRD, Ifremer, LEMAR, 29280 Plouzane, France
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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.
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
Revised manuscript accepted 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
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.
Asmita Singh, Susanne Fietz, Sandy J. Thomalla, Nicolas Sanchez, Murat V. Ardelan, Sébastien Moreau, Hanna M. Kauko, Agneta Fransson, Melissa Chierici, Saumik Samanta, Thato N. Mtshali, Alakendra N. Roychoudhury, and Thomas J. Ryan-Keogh
Biogeosciences, 20, 3073–3091, https://doi.org/10.5194/bg-20-3073-2023, https://doi.org/10.5194/bg-20-3073-2023, 2023
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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.
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.
Marion Lagarde, Nolwenn Lemaitre, Hélène Planquette, Mélanie Grenier, Moustafa Belhadj, Pascale Lherminier, and Catherine Jeandel
Biogeosciences, 17, 5539–5561, https://doi.org/10.5194/bg-17-5539-2020, https://doi.org/10.5194/bg-17-5539-2020, 2020
Manon Tonnard, Hélène Planquette, Andrew R. Bowie, Pier van der Merwe, Morgane Gallinari, Floriane Desprez de Gésincourt, Yoan Germain, Arthur Gourain, Marion Benetti, Gilles Reverdin, Paul Tréguer, Julia Boutorh, Marie Cheize, François Lacan, Jan-Lukas Menzel Barraqueta, Leonardo Pereira-Contreira, Rachel Shelley, Pascale Lherminier, and Géraldine Sarthou
Biogeosciences, 17, 917–943, https://doi.org/10.5194/bg-17-917-2020, https://doi.org/10.5194/bg-17-917-2020, 2020
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We investigated the spatial distribution of dissolved Fe during spring 2014, in order to understand the processes influencing the biogeochemical cycle in the North Atlantic. Our results highlighted elevated Fe close to riverine inputs at the Iberian Margin and glacial inputs at the Newfoundland and Greenland margins. Atmospheric deposition appeared to be a minor source of Fe. Convection was an important source of Fe in the Irminger Sea, which was depleted in Fe relative to nitrate.
Arthur Gourain, Hélène Planquette, Marie Cheize, Nolwenn Lemaitre, Jan-Lukas Menzel Barraqueta, Rachel Shelley, Pascale Lherminier, and Géraldine Sarthou
Biogeosciences, 16, 1563–1582, https://doi.org/10.5194/bg-16-1563-2019, https://doi.org/10.5194/bg-16-1563-2019, 2019
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The GEOVIDE cruise (May–June 2014, R/V Pourquoi Pas?) aimed to provide a better understanding of trace metal biogeochemical cycles in the North Atlantic. As particles play a key role in the global biogeochemical cycle of trace elements in the ocean, we discuss the distribution of particulate iron (PFe). Lithogenic sources appear to dominate the PFe cycle through margin and benthic inputs.
Jan-Lukas Menzel Barraqueta, Jessica K. Klar, Martha Gledhill, Christian Schlosser, Rachel Shelley, Hélène F. Planquette, Bernhard Wenzel, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 16, 1525–1542, https://doi.org/10.5194/bg-16-1525-2019, https://doi.org/10.5194/bg-16-1525-2019, 2019
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We used surface water dissolved aluminium concentrations collected in four different GEOTRACES cruises to determine atmospheric deposition fluxes to the ocean. We calculate atmospheric deposition fluxes for largely under-sampled regions of the Atlantic Ocean and thus provide new constraints for models of atmospheric deposition. The use of the MADCOW model is of major importance as dissolved aluminium is analysed within the GEOTRACES project at high spatial resolution.
Debany Fonseca-Batista, Xuefeng Li, Virginie Riou, Valérie Michotey, Florian Deman, François Fripiat, Sophie Guasco, Natacha Brion, Nolwenn Lemaitre, Manon Tonnard, Morgane Gallinari, Hélène Planquette, Frédéric Planchon, Géraldine Sarthou, Marc Elskens, Julie LaRoche, Lei Chou, and Frank Dehairs
Biogeosciences, 16, 999–1017, https://doi.org/10.5194/bg-16-999-2019, https://doi.org/10.5194/bg-16-999-2019, 2019
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Dinitrogen fixation and primary production were investigated using stable isotope incubation experiments along two transects off the Western Iberian Margin in May 2014 close to the end of the phytoplankton spring bloom. We observed substantial N2 fixation activities (up to 1533 µmol N m-2 d-1) associated with a predominance of unicellular cyanobacteria and non-cyanobacterial diazotrophs, which seemed to be promoted by the presence of bloom-derived organic matter and excess phosphorus.
Yi Tang, Nolwenn Lemaitre, Maxi Castrillejo, Montserrat Roca-Martí, Pere Masqué, and Gillian Stewart
Biogeosciences, 16, 309–327, https://doi.org/10.5194/bg-16-309-2019, https://doi.org/10.5194/bg-16-309-2019, 2019
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Oceanographers try to understand the ocean’s role in the global carbon cycle. Trace levels of natural radionuclides can inform this connection and their half-lives provide an estimate of the timing of processes. We used the 210Po and 210Pb pair to examine the export of carbon from the surface ocean to depth along the GEOVIDE GEOTRACES cruise track. We found that the flux was regionally variable, that upwelling was an important regional factor, and that both large and small particles drove flux.
Géraldine Sarthou, Pascale Lherminier, Eric P. Achterberg, Fernando Alonso-Pérez, Eva Bucciarelli, Julia Boutorh, Vincent Bouvier, Edward A. Boyle, Pierre Branellec, Lidia I. Carracedo, Nuria Casacuberta, Maxi Castrillejo, Marie Cheize, Leonardo Contreira Pereira, Daniel Cossa, Nathalie Daniault, Emmanuel De Saint-Léger, Frank Dehairs, Feifei Deng, Floriane Desprez de Gésincourt, Jérémy Devesa, Lorna Foliot, Debany Fonseca-Batista, Morgane Gallinari, Maribel I. García-Ibáñez, Arthur Gourain, Emilie Grossteffan, Michel Hamon, Lars Eric Heimbürger, Gideon M. Henderson, Catherine Jeandel, Catherine Kermabon, François Lacan, Philippe Le Bot, Manon Le Goff, Emilie Le Roy, Alison Lefèbvre, Stéphane Leizour, Nolwenn Lemaitre, Pere Masqué, Olivier Ménage, Jan-Lukas Menzel Barraqueta, Herlé Mercier, Fabien Perault, Fiz F. Pérez, Hélène F. Planquette, Frédéric Planchon, Arnout Roukaerts, Virginie Sanial, Raphaëlle Sauzède, Catherine Schmechtig, Rachel U. Shelley, Gillian Stewart, Jill N. Sutton, Yi Tang, Nadine Tisnérat-Laborde, Manon Tonnard, Paul Tréguer, Pieter van Beek, Cheryl M. Zurbrick, and Patricia Zunino
Biogeosciences, 15, 7097–7109, https://doi.org/10.5194/bg-15-7097-2018, https://doi.org/10.5194/bg-15-7097-2018, 2018
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The GEOVIDE cruise (GEOTRACES Section GA01) was conducted in the North Atlantic Ocean and Labrador Sea in May–June 2014. In this special issue, results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 17 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.
Nolwenn Lemaitre, Frédéric Planchon, Hélène Planquette, Frank Dehairs, Debany Fonseca-Batista, Arnout Roukaerts, Florian Deman, Yi Tang, Clarisse Mariez, and Géraldine Sarthou
Biogeosciences, 15, 6417–6437, https://doi.org/10.5194/bg-15-6417-2018, https://doi.org/10.5194/bg-15-6417-2018, 2018
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We investigated the surface particulate organic carbon export fluxes in the North Atlantic with the objective of better understanding the biological carbon pump. Our results highlighted that exports depended on the intensity and stage of the bloom, the phytoplankton size and community structures. After comparing with primary production, we concluded that, during our study, the North Atlantic behaves like most of the highly productive areas in the world's ocean, with a low export efficiency.
Maxi Castrillejo, Núria Casacuberta, Marcus Christl, Christof Vockenhuber, Hans-Arno Synal, Maribel I. García-Ibáñez, Pascale Lherminier, Géraldine Sarthou, Jordi Garcia-Orellana, and Pere Masqué
Biogeosciences, 15, 5545–5564, https://doi.org/10.5194/bg-15-5545-2018, https://doi.org/10.5194/bg-15-5545-2018, 2018
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The investigation of water mass transport pathways and timescales is important to understand the global ocean circulation. Following earlier studies, we use artificial radionuclides introduced to the oceans in the 1950s to investigate the water transport in the subpolar North Atlantic (SPNA). For the first time, we combine measurements of the long-lived iodine-129 and uranium-236 to confirm earlier findings/hypotheses and to better understand shallow and deep ventilation processes in the SPNA.
Yi Tang, Maxi Castrillejo, Montserrat Roca-Martí, Pere Masqué, Nolwenn Lemaitre, and Gillian Stewart
Biogeosciences, 15, 5437–5453, https://doi.org/10.5194/bg-15-5437-2018, https://doi.org/10.5194/bg-15-5437-2018, 2018
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We measured two natural radio-isotopes, 210Po and 210Pb, in the dissolved and particulate phase along the GEOVIDE cruise track to try to understand the cycling of these isotopes across a diverse combination of currents, basins, and conditions in the North Atlantic Ocean. Other groups collected data on many other trace elements and isotopes in order to map them as part of the GEOTRACES program. We found that Po and Pb activity was concentrated on small particles and varied within/between basins.
Jan-Lukas Menzel Barraqueta, Christian Schlosser, Hélène Planquette, Arthur Gourain, Marie Cheize, Julia Boutorh, Rachel Shelley, Leonardo Contreira Pereira, Martha Gledhill, Mark J. Hopwood, François Lacan, Pascale Lherminier, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 15, 5271–5286, https://doi.org/10.5194/bg-15-5271-2018, https://doi.org/10.5194/bg-15-5271-2018, 2018
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In the North Atlantic and Labrador Sea, low aerosol deposition and enhanced primary productivity control the dissolved aluminium (dAl) surface distribution, while remineralization of particles seems to control the distribution at depth. DAl in the ocean allows us to indirectly quantify the amount of dust deposited to a given region for a given period. Hence, the study of its distribution, cycling, sources, and sinks is of major importance to improve aerosol deposition models and climate models.
Cheryl M. Zurbrick, Edward A. Boyle, Richard J. Kayser, Matthew K. Reuer, Jingfeng Wu, Hélène Planquette, Rachel Shelley, Julia Boutorh, Marie Cheize, Leonardo Contreira, Jan-Lukas Menzel Barraqueta, François Lacan, and Géraldine Sarthou
Biogeosciences, 15, 4995–5014, https://doi.org/10.5194/bg-15-4995-2018, https://doi.org/10.5194/bg-15-4995-2018, 2018
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During a French cruise in the northern North Atlantic Ocean in 2014, seawater samples were collected for dissolved Pb and Pb isotope analysis. Lead concentrations were highest in subsurface water flowing out of the Mediterranean Sea. The recently formed Labrador Sea Water (LSW) is much lower in Pb concentration than older LSW found in the West European Basin. Comparison of North Atlantic data from 1981 to 2014 shows decreasing Pb concentrations down to ~ 2500 m depth.
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
Short summary
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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.
Emilie Le Roy, Virginie Sanial, Matthew A. Charette, Pieter van Beek, François Lacan, Stéphanie H. M. Jacquet, Paul B. Henderson, Marc Souhaut, Maribel I. García-Ibáñez, Catherine Jeandel, Fiz F. Pérez, and Géraldine Sarthou
Biogeosciences, 15, 3027–3048, https://doi.org/10.5194/bg-15-3027-2018, https://doi.org/10.5194/bg-15-3027-2018, 2018
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We report detailed sections of radium-226 (226Ra, T1/2 = 1602 y) activities and barium (Ba) concentrations determined in the North Atlantic (Portugal–Greenland–Canada) in the framework of the international GEOTRACES program (GA01 section–GEOVIDE project, May–July 2014). Dissolved 226Ra and Ba are strongly correlated along the section, which may reflect their similar chemical behavior.
Nolwenn Lemaitre, Hélène Planquette, Frédéric Planchon, Géraldine Sarthou, Stéphanie Jacquet, Maribel I. García-Ibáñez, Arthur Gourain, Marie Cheize, Laurence Monin, Luc André, Priya Laha, Herman Terryn, and Frank Dehairs
Biogeosciences, 15, 2289–2307, https://doi.org/10.5194/bg-15-2289-2018, https://doi.org/10.5194/bg-15-2289-2018, 2018
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We present the particulate biogenic barium distributions in the North Atlantic for the first time with the objective of estimating mesopelagic carbon remineralisation fluxes. The remineralisation fluxes balanced or slightly exceeded the upper-ocean carbon export fluxes. This is a key result as the North Atlantic is generally assumed to be efficient in transferring carbon to the deep ocean, but during our study, the North Atlantic was characterized by a near-zero carbon sequestration efficiency.
Daniel Cossa, Lars-Eric Heimbürger, Fiz F. Pérez, Maribel I. García-Ibáñez, Jeroen E. Sonke, Hélène Planquette, Pascale Lherminier, Julia Boutorh, Marie Cheize, Jan Lukas Menzel Barraqueta, Rachel Shelley, and Géraldine Sarthou
Biogeosciences, 15, 2309–2323, https://doi.org/10.5194/bg-15-2309-2018, https://doi.org/10.5194/bg-15-2309-2018, 2018
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We first report the mercury distribution in the water section across the subpolar and subtropical gyres of the North Atlantic Ocean (GEOTRACES-GA01 transect). It allows the characterisation of various seawater types in terms of mercury content and the quantification of mercury transport associated with the Atlantic Meridional Overturning Circulation. It shows the nutrient-like biogeochemical behaviour of mercury in this ocean.
Rachel U. Shelley, William M. Landing, Simon J. Ussher, Helene Planquette, and Geraldine Sarthou
Biogeosciences, 15, 2271–2288, https://doi.org/10.5194/bg-15-2271-2018, https://doi.org/10.5194/bg-15-2271-2018, 2018
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In this study, we discuss the regional variability in the fractional solubility of trace elements (Al, Ti, Fe, Mn, Co, Ni, Cu, Zn, Cd, Pb) from aerosol samples collected during three cruises to the North Atlantic Ocean. We present data that provides a
solubility window, covering a conservative, lower limit to an upper limit, the maximum potentially soluble fraction, and discuss why this upper limit could be used to represent the biologically available fraction in some regions.
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 %.
A. R. Bowie, P. van der Merwe, F. Quéroué, T. Trull, M. Fourquez, F. Planchon, G. Sarthou, F. Chever, A. T. Townsend, I. Obernosterer, J.-B. Sallée, and S. Blain
Biogeosciences, 12, 4421–4445, https://doi.org/10.5194/bg-12-4421-2015, https://doi.org/10.5194/bg-12-4421-2015, 2015
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Iron biogeochemical budgets during the natural ocean fertilisation experiment KEOPS-2 showed that complex circulation and transport pathways were responsible for differences in the mode and strength of iron supply, with vertical supply dominant on the plateau and lateral supply dominant in the plume. The exchange of iron between dissolved, biogenic and lithogenic pools was highly dynamic, resulting in a decoupling of iron supply and carbon export and controlling the efficiency of fertilization.
F. Quéroué, G. Sarthou, H. F. Planquette, E. Bucciarelli, F. Chever, P. van der Merwe, D. Lannuzel, A. T. Townsend, M. Cheize, S. Blain, F. d'Ovidio, and A. R. Bowie
Biogeosciences, 12, 3869–3883, https://doi.org/10.5194/bg-12-3869-2015, https://doi.org/10.5194/bg-12-3869-2015, 2015
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Dissolved Fe (dFe) concentrations were measured in the vicinity of the Kerguelen Islands. Direct island runoff, glacial melting, and resuspended sediments were identified as important inputs of dFe that could potentially fertilise the northern part of the plateau. Overall, heterogeneous sources of Fe over and off the plateau, in addition to strong variability in Fe supply by vertical or horizontal transport, may explain the high variability in dFe concentrations observed during this study.
L. Farías, L. Florez-Leiva, V. Besoain, G. Sarthou, and C. Fernández
Biogeosciences, 12, 1925–1940, https://doi.org/10.5194/bg-12-1925-2015, https://doi.org/10.5194/bg-12-1925-2015, 2015
P. van der Merwe, A. R. Bowie, F. Quéroué, L. Armand, S. Blain, F. Chever, D. Davies, F. Dehairs, F. Planchon, G. Sarthou, A. T. Townsend, and T. W. Trull
Biogeosciences, 12, 739–755, https://doi.org/10.5194/bg-12-739-2015, https://doi.org/10.5194/bg-12-739-2015, 2015
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Trace metal analysis of suspended and settling particles and underlying sediment was undertaken to elucidate the source to sink progression of the particulate trace metal pool near Kerguelen Island (Southern Ocean). Findings indicate that the Kerguelen Plateau is a source of trace metals via resuspended shelf sediments, especially below the mixed layer. However, glacial/fluvial runoff into shallow coastal waters is an important mode of fertilisation to areas downstream of Kerguelen Island.
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Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone
Optimal parameters for the ocean's nutrient, carbon, and oxygen cycles compensate for circulation biases but replumb the biological pump
Importance of multiple sources of iron for the upper-ocean biogeochemistry over the northern Indian Ocean
Exploring the role of different data types and timescales in the quality of marine biogeochemical model calibration
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David Curbelo-Hernández, Fiz F. Pérez, Melchor González-Dávila, Sergey V. Gladyshev, Aridane G. González, David González-Santana, Antón Velo, Alexey Sokov, and J. Magdalena Santana-Casiano
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The study evaluated CO2–carbonate system dynamics in the North Atlantic subpolar gyre during 2009–2019. Significant ocean acidification, largely due to rising anthropogenic CO2 levels, was found. Cooling, freshening, and enhanced convective processes intensified this trend, affecting calcite and aragonite saturation. The findings contribute to a deeper understanding of ocean acidification and improve our knowledge about its impact on marine ecosystems.
Medhavi Pandey, Haimanti Biswas, Daniel Birgel, Nicole Burdanowitz, and Birgit Gaye
Biogeosciences, 21, 4681–4698, https://doi.org/10.5194/bg-21-4681-2024, https://doi.org/10.5194/bg-21-4681-2024, 2024
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We analysed sea surface temperature (SST) proxy and plankton biomarkers in sediments that accumulate sinking material signatures from surface waters in the central Arabian Sea (21°–11° N, 64° E), a tropical basin impacted by monsoons. We saw a north–south SST gradient, and the biological proxies showed more organic matter from larger algae in the north. Smaller algae and zooplankton were more numerous in the south. These trends were related to ocean–atmospheric processes and oxygen availability.
Allison Hogikyan and Laure Resplandy
Biogeosciences, 21, 4621–4636, https://doi.org/10.5194/bg-21-4621-2024, https://doi.org/10.5194/bg-21-4621-2024, 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, not by the direct effect of warming on carbon chemistry and pH. These evaporation and rainfall patterns oppose acidification in saltier parts of the ocean and enhance acidification in fresher regions.
Huailin Deng, Koji Suzuki, Ichiro Yasuda, Hiroshi Ogawa, and Jun Nishioka
EGUsphere, https://doi.org/10.5194/egusphere-2024-3064, https://doi.org/10.5194/egusphere-2024-3064, 2024
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Iron (Fe) and nitrate are vital for primary production in the North Pacific. Sedimentary Fe is carried by North Pacific Intermediate Water to the north Pacific, but the nutrient return path and its effect on phytoplankton are unclear. By combining Fe and macronutrient fluxes with phytoplankton composition, this study firstly revealed that Fe supply from subsurface greatly controls diatom abundance and identified the nutrient return path in the subarctic gyre and Kuroshio-Oyashio Transition Area.
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.
Madhavan Girijakumari Keerthi, Olivier Aumont, Lester Kwiatkowski, and Marina Levy
EGUsphere, https://doi.org/10.5194/egusphere-2024-2294, https://doi.org/10.5194/egusphere-2024-2294, 2024
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Our study assesses the capability of CMIP6 models to reproduce satellite observations of sub-seasonal chlorophyll variability. Models struggle to reproduce the sub-seasonal variance and its contribution across timescales. Some models overestimate sub-seasonal variance and exaggerate its role in annual fluctuations, while others underestimate it. Underestimation is likely due to the coarse resolution of models, while overestimation may result from intrinsic oscillations in biogeochemical models.
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.
Jens Terhaar
EGUsphere, https://doi.org/10.5194/egusphere-2024-2171, https://doi.org/10.5194/egusphere-2024-2171, 2024
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The ocean is a major natural carbon sink. Despite its importance, estimates of the ocean carbon sink remain uncertain. Here, I present a hybrid model estimate of the ocean carbon sink from 1959 to 2022. By combining ocean models in hindcast mode and Earth System Models, I keep the strength of each approach and remove the respective weaknesses. This hybrid model estimate is similar in magnitude than the best estimate of the Global Carbon Budget but 70 % less uncertain.
Naoya Kanna, Kazutaka Tateyama, Takuji Waseda, Anna Timofeeva, Maria Papadimitraki, Laura Whitmore, Hajime Obata, Daiki Nomura, Hiroshi Ogawa, Youhei Yamashita, and Igor Polyakov
EGUsphere, https://doi.org/10.5194/egusphere-2024-1834, https://doi.org/10.5194/egusphere-2024-1834, 2024
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This article presents data on iron and manganese, which are essential micronutrients for primary producers, on the surface of the Arctic’s Laptev and East Siberian Seas (LESS). Observations were made in international cooperation with the NABOS expedition during the late summer of 2021 in the Arctic Ocean. The results from this study indicate that the major factors controlling these metal concentrations in LESS are river discharge and the input of shelf sediment.
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.
Alexandre Accardo, Rémi Laxenaire, Alberto Baudena, Sabrina Speich, Rainer Kiko, and Lars Stemmann
EGUsphere, https://doi.org/10.5194/egusphere-2024-1558, https://doi.org/10.5194/egusphere-2024-1558, 2024
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The open ocean helps mitigate climate change by storing CO2 through the biological carbon pump (BCP). The BCP involves processes like phytoplankton capturing CO2 and sequestering it in the deep ocean via marine snow production. We found significant marine snow accumulation from the surface to 600 meters deep in frontal regions between eddies. We suggest that the coupling of hydrodynamics at eddy edges and biological activity (via planktonic organisms) may enhanced this process.
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.
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.
Ben J. Fisher, Alex J. Poulton, Michael P. Meredith, Kimberlee Baldry, Oscar Schofield, and Sian F. Henley
EGUsphere, https://doi.org/10.5194/egusphere-2024-990, https://doi.org/10.5194/egusphere-2024-990, 2024
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The Southern Ocean is a rapidly warming environment, with subsequent impacts on ecosystems and biogeochemical cycling. This study examines changes in phytoplankton and biogeochemistry using a range of climate models. Under climate change the Southern Ocean will be warmer, more acidic, more productive and have reduced nutrient availability by 2100. However, there is substantial variability between models across key productivity parameters, we propose ways of reducing this uncertainty.
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.
Allanah Joy Paul, Mathias Haunost, Silvan Urs Goldenberg, Jens Hartmann, Nicolás Sánchez, Julieta Schneider, Niels Suitner, and Ulf Riebesell
EGUsphere, https://doi.org/10.5194/egusphere-2024-417, https://doi.org/10.5194/egusphere-2024-417, 2024
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Ocean alkalinity enhancement (OAE) is being assessed for its potential to absorb atmospheric CO2 and store it for a long time. OAE still needs comprehensive assessment of its safety and effectiveness. We studied an idealised OAE application in a natural low nutrient ecosystem over one month. Our results showed that biogeochemical functioning remained mostly stable, but that the long-term capability for storing carbon may be limited at high alkalinity concentration.
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.
Asmita Singh, Susanne Fietz, Sandy J. Thomalla, Nicolas Sanchez, Murat V. Ardelan, Sébastien Moreau, Hanna M. Kauko, Agneta Fransson, Melissa Chierici, Saumik Samanta, Thato N. Mtshali, Alakendra N. Roychoudhury, and Thomas J. Ryan-Keogh
Biogeosciences, 20, 3073–3091, https://doi.org/10.5194/bg-20-3073-2023, https://doi.org/10.5194/bg-20-3073-2023, 2023
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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.
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.
Cited articles
Anilkumar, N. and Sabu, P.: Physical process influencing the ecosystem of
the indian sector of southern ocean-An overview, Proc. Indian Natl. Sci.
Acad., 83, 363–376, https://doi.org/10.16943/ptinsa/2017/48960, 2017.
Ansorge, I. J., Jackson, J. M., Reid, K., Durgadoo, J. V, Swart, S., and
Eberenz, S.: Evidence of a southward eddy corridor in the South-West Indian
ocean, Deep-Sea Res. Pt. II, 119, 69–76,
https://doi.org/10.1016/j.dsr2.2014.05.012, 2015.
Armstrong, R. A., Peterson, M. L., Lee, C., and Wakeham, S. G.: Settling
velocity spectra and the ballast ratio hypothesis, Deep-Sea Res. Pt. II, 56, 1470–1478, https://doi.org/10.1016/j.dsr2.2008.11.032, 2009.
Barbur, V. A., Montgomery, D. C., and Peck, E. A.: Introduction to Linear
Regression Analysis, Stat., 43, 339, https://doi.org/10.2307/2348362, 1994.
Behrenfeld, M. J., Boss, E., Siegel, D. A., and Shea, D. M.: Carbon-based
ocean productivity and phytoplankton physiology from space, Global Biogeochem. Cy., 19, 1–14, https://doi.org/10.1029/2004GB002299, 2005.
Bishop, J. K. B.: The barite-opal-organic carbon association in oceanic
particulate matter, Nature, 332, 341–343, https://doi.org/10.1038/332341a0, 1988.
Bishop, J. K. B. and Edmond, J. M.: A new large volume filtration system for
the sampling of oceanic particulate matter, J. Mar. Res., 34, 181–198, 1976.
Bopp, L., Resplandy, L., Orr, J. C., Doney, S. C., Dunne, J. P., Gehlen, M., Halloran, P., Heinze, C., Ilyina, T., Séférian, R., Tjiputra, J., and Vichi, M.: Multiple stressors of ocean ecosystems in the 21st century: projections with CMIP5 models, Biogeosciences, 10, 6225–6245, https://doi.org/10.5194/bg-10-6225-2013, 2013.
Boyd, P. W., Claustre, H., Levy, M., Siegel, D. A. and Weber, T.:
Multi-faceted particle pumps drive carbon sequestration in the ocean,
Nature, 568, 327–335, https://doi.org/10.1038/s41586-019-1098-2, 2019.
Broecker, W. S., Takahashi, T. and Takahashi, T.: Sources and flow patterns
of deep-ocean waters as deduced from potential temperature, salinity, and
initial phosphate concentration, J. Geophys. Res.-Oceans, 90,
6925–6939, https://doi.org/10.1029/JC090iC04p06925, 1985.
Buesseler, K. O.: The decoupling of production and particulate export in
the surface ocean, Global Biogeochem. Cy., 12, 297–310,
https://doi.org/10.1029/97GB03366, 1998.
Buesseler, K. O., Andrews, J. E., Pike, S. M., Charette, M. A., Goldson, L.
E., Brzezinski, M. A., and Lance, V. P.: Particle export during the Southern
Ocean Iron Experiment (SOFeX), Limnol. Oceanogr., 50, 311–327,
https://doi.org/10.4319/lo.2005.50.1.0311, 2005.
Buesseler, K. O. and Boyd, P. W.: Shedding light on processes that control
particle export and flux attenuation in the twilight zone of the open ocean,
Limnol. Oceanogr., 54, 1210–1232, https://doi.org/10.4319/lo.2009.54.4.1210, 2009.
Cardinal, D., Dehairs, F., Cattaldo, T., and André, L.: Geochemistry of
suspended particles in the Subantarctic and Polar Frontal zones south of
Australia: Constraints on export and advection processes, J. Geophys. Res.-Ocean., 106, 31637–31656, https://doi.org/10.1029/2000JC000251, 2001.
Cardinal, D., Savoye, N., Trull, T. W., André, L., Kopczynska, E. E.,
and Dehairs, F.: Variations of carbon remineralisation in the Southern Ocean
illustrated by the Baxs proxy, Deep-Sea Res. Pt. I, 52,
355–370, https://doi.org/10.1016/j.dsr.2004.10.002, 2005.
Cavan, E. L., Le Moigne, F. A. C., Poulton, A. J., Tarling, G. A., Ward, P.,
Daniels, C. J., Fragoso, G. M., and Sanders, R. J.: Attenuation of
particulate organic carbon flux in the Scotia Sea, Southern Ocean, is
controlled by zooplankton fecal pellets, Geophys. Res. Lett., 42,
821–830, https://doi.org/10.1002/2014GL062744, 2015.
Cutter, G., Casciotti, K., Croot, P., Geibert, W., Heimbürger, L.-E.,
Lohan, M., Planquette, H., and van de Flierdt, T.: Sampling and
Sample-handling Protocols for GEOTRACES Cruises, Version 3, 139 pp.,
http://www.geotraces.org/images/stories/documents/intercalibration/Cookbook.pdf (last access: 15 February 2019),
2017.
de Boyer Montégut, C., Madec, G., Fischer, A. S., Lazar, A., and
Iudicone, D.: Mixed layer depth over the global ocean: An examination of
profile data and a profile-based climatology, J. Geophys. Res.-Oceans,
109, 1–20, https://doi.org/10.1029/2004JC002378, 2004.
Dehairs, F., Baeyens, W. and Goeyens, L.: Accumulation of Suspended Barite
at Mesopelagic Depths and Export Production in the Southern Ocean, Science 258, 1332–1335, https://doi.org/10.1126/SCIENCE.258.5086.1332, 1992.
Dehairs, F., Chesselet, R., and Jedwab, J.: Discrete suspended particles of
barite and the barium cycle in the open ocean, Earth Planet. Sc. Lett.,
49, 528–550, https://doi.org/10.1016/0012-821X(80)90094-1, 1980.
Dehairs, F. and Goeyens, L.: Oxidation rate of organic carbon in the
mesopelagic water column as traced by suspended barium-barite, Integr. Mar.
Syst. Anal., 205–217, 1996.
Dehairs, F., Goeyens, L., Stroobants, N., Bernard, P., Goyet, C., Poisson,
A. and Chesselet, R.: On suspended barite and the oxygen minimum in the
Southern Ocean, Global Biogeochem. Cy., 4, 85–102,
https://doi.org/10.1029/GB004I001P00085, 1990.
Dehairs, F., Shopova, D., Ober, S., Veth, C. and Goeyens, L.: Particulate
barium stocks and oxygen consumption in the Southern Ocean mesopelagic water
column during spring and early summer: Relationship with export production,
Deep-Sea Res. Pt. II, 44, 497–516,
https://doi.org/10.1016/S0967-0645(96)00072-0, 1997.
Dehairs, F., Stroobants, N., and Goeyens, L.: Suspended barite as a tracer of
biological activity in the Southern Ocean, Mar. Chem., 35, 399–410,
https://doi.org/10.1016/S0304-4203(09)90032-9, 1991.
de Jong, E., Vichi, M., Mehlmann, C. B., Eayrs, C., De Kock, W.,
Moldenhauer, M., and Audh, R. R.: Sea Ice conditions within the Antarctic
Marginal Ice Zone in winter 2017, onboard the SA Agulhas II, Univ. Cape
Town, PANGAEA, https://doi.org/10.1594/PANGAEA.885211, 2018.
DeVries, T. and Weber, T.: The export and fate of organic matter in the
ocean: New constraints from combining satellite and oceanographic tracer
observations, Global Biogeochem. Cy., 31, 535–555,
https://doi.org/10.1002/2016GB005551, 2017.
Ducklow, H. W., Steinberg, D. K., and Buesseler, K. O.: Upper ocean carbon
export and the biological pump, Oceanography, 14, 50–58,
https://doi.org/10.5670/oceanog.2001.06, 2001.
Dymond, J., Suess, E., and Lyle, M.: Barium in Deep-Sea Sediment: A
Geochemical Proxy for Paleoproductivity, Paleoceanography, 7, 163–181,
https://doi.org/10.1029/92PA00181, 1992.
Ehrhardt, M., Grasshoff, K., Kremling, K., and Almgren,
T. (Eds.): Methods of seawater analysis, edited by: Grasshoff, K., Ehrhardt, M., and Kremling, K.; with contributions by T. Almgren,
Verlag Chemie, Weinheim, 1983.
Eriksen, R., Trull, T. W., Davies, D., Jansen, P., Davidson, A. T.,
Westwood, K., and Van Den Enden, R.: Seasonal succession of phytoplankton
community structure from autonomous sampling at the Australian Southern
Ocean Time Series (SOTS) observatory, Mar. Ecol. Prog. Ser., 589, 13–21,
https://doi.org/10.3354/meps12420, 2018.
Fan, G., Han, Z., Ma, W., Chen, S., Chai, F., Mazloff, M. R., Pan, J., and
Zhang, H.: Southern Ocean carbon export efficiency in relation to
temperature and primary productivity, Sci. Rep., 10, 1–11,
https://doi.org/10.1038/s41598-020-70417-z, 2020.
Ferrari, R. and Nikurashin, M.: Suppression of eddy diffusivity across jets
in the Southern Ocean, J. Phys. Oceanogr., 40, 1501–1519,
https://doi.org/10.1175/2010JPO4278.1, 2010.
Freeman, N. M., Lovenduski, N. S., Munro, D. R., Krumhardt, K. M., Lindsay,
K., Long, M. C., and Maclennan, M.: The Variable and Changing Southern Ocean
Silicate Front: Insights from the CESM Large Ensemble, Global Biogeochem. Cy., 32, 752–768, https://doi.org/10.1029/2017GB005816, 2018.
Gall, M. P., Boyd, P. W., Hall, J., Safi, K. A., and Chang, H.:
Phytoplankton processes, Part 1: Community structure during the Southern
Ocean Iron RElease Experiment (SOIREE), Deep-Sea Res. Pt. II, 48, 2551–2570, https://doi.org/10.1016/S0967-0645(01)00008-X, 2001.
GEOTRACES Intermediate Data Product Group: The GEOTRACES Intermediate Data
Product 2021 (IDP2021), NERC EDS British Oceanographic Data Centre NOC, [data set], https://doi.org/10.5285/cf2d9ba9-d51d-3b7c-e053-8486abc0f5fd, 2021.
Gill, A. E.: Atmosphere-ocean dynamics, NEW YORK, U.S.A., ACADEMIC PRESS
INC., https://doi.org/10.1016/0141-1187(83)90039-1, 1982.
Gregor, L., Lebehot, A. D., Kok, S., and Scheel Monteiro, P. M.: A comparative assessment of the uncertainties of global surface ocean CO2 estimates using a machine-learning ensemble (CSIR-ML6 version 2019a) – have we hit the wall?, Geosci. Model Dev., 12, 5113–5136, https://doi.org/10.5194/gmd-12-5113-2019, 2019.
Gruber, N., Landschützer, P., and Lovenduski, N. S.: The variable
southern ocean carbon sink, Ann. Rev. Mar. Sci., 11, 159–186,
https://doi.org/10.1146/annurev-marine-121916-063407, 2019.
Honjo, S., Eglinton, T. I., Taylor, C. D., Ulmer, K. M., Sievert, S. M.,
Bracher, A., German, C. R., Edgcomb, V., Francois, R.,
Deboraiglesias-Rodriguez, M., Van Mooy, B., and Repeta, D. J.: Understanding
the role of the biological pump in the global carbon cycle: An imperative
for ocean science, Oceanography, 27, 10–16, https://doi.org/10.5670/oceanog.2014.78,
2014.
Ito, T., Follows, M. J., and Boyle, E. A.: Is AOU a good measure of
respiration in the oceans?, Geophys. Res. Lett., 31, 1–4,
https://doi.org/10.1029/2004GL020900, 2004.
Jacquet, S. H. M., Dehairs, F., Cardinal, D., Navez, J., and Delille, B.:
Barium distribution across the Southern Ocean frontal system in the
Crozet-Kerguelen Basin, Mar. Chem., 95, 149–162,
https://doi.org/10.1016/j.marchem.2004.09.002, 2005.
Jacquet, S. H. M., Dehairs, F., Elskens, M., Savoye, N., and Cardinal, D.:
Barium cycling along WOCE SR3 line in the Southern Ocean, Mar. Chem.,
106, 33–45, https://doi.org/10.1016/j.marchem.2006.06.007, 2007.
Jacquet, S. H. M., Dehairs, F., Savoye, N., Obernosterer, I., Christaki, U.,
Monnin, C., and Cardinal, D.: Mesopelagic organic carbon remineralization in
the Kerguelen Plateau region tracked by biogenic particulate Ba, Deep-Sea Res. Pt. II, 55, 868–879,
https://doi.org/10.1016/j.dsr2.2007.12.038, 2008a.
Jacquet, S. H. M., Savoye, N., Dehairs, F., Strass, V. H., and Cardinal, D.:
Mesopelagic carbon remineralization during the European Iron Fertilization
Experiment, Global Biogeochem. Cy., 22, 1–9,
https://doi.org/10.1029/2006GB002902, 2008b.
Jacquet, S. H. M., Dehairs, F., Dumont, I., Becquevort, S., Cavagna, A. J.,
and Cardinal, D.: Twilight zone organic carbon remineralization in the Polar
Front Zone and Subantarctic Zone south of Tasmania, Deep-Sea Res. Pt. II, 58, 2222–2234, https://doi.org/10.1016/j.dsr2.2011.05.029,
2011.
Jacquet, S. H. M., Dehairs, F., Lefèvre, D., Cavagna, A. J., Planchon, F., Christaki, U., Monin, L., André, L., Closset, I., and Cardinal, D.: Early spring mesopelagic carbon remineralization and transfer efficiency in the naturally iron-fertilized Kerguelen area, Biogeosciences, 12, 1713–1731, https://doi.org/10.5194/bg-12-1713-2015, 2015.
Jochum, K. P., Nohl, U., Herwig, K., Lammel, E., Stoll, B., and Hofmann, A.
W.: GeoReM: A new geochemical database for reference materials and isotopic
standards, Geostand. Geoanal. Res., 29, 333–338,
https://doi.org/10.1111/j.1751-908x.2005.tb00904.x, 2005.
Kokoska, S. and Zwillinger, D.: CRC Standard Probability and Statistics
Tables and Formulae, Student Edition, https://doi.org/10.1201/b16923, 2000.
Lam, P. J. and Bishop, J. K. B.: High biomass, low export regimes in the
Southern Ocean, Deep-Sea Res. Pt. II, 54, 601–638,
https://doi.org/10.1016/j.dsr2.2007.01.013, 2007.
Laurenceau-Cornec, E. C., Trull, T. W., Davies, D. M., Bray, S. G., Doran, J., Planchon, F., Carlotti, F., Jouandet, M.-P., Cavagna, A.-J., Waite, A. M., and Blain, S.: The relative importance of phytoplankton aggregates and zooplankton fecal pellets to carbon export: insights from free-drifting sediment trap deployments in naturally iron-fertilised waters near the Kerguelen Plateau, Biogeosciences, 12, 1007–1027, https://doi.org/10.5194/bg-12-1007-2015, 2015.
Le Moigne, F. A. C.: Pathways of Organic Carbon Downward Transport by the
Oceanic Biological Carbon Pump, Front. Mar. Sci., 634, 6,
https://doi.org/10.3389/fmars.2019.00634, 2019.
Legeleux, F. and Reyss, J. L.: 228Ra
Lemaitre, N., Planquette, H., Planchon, F., Sarthou, G., Jacquet, S., García-Ibáñez, M. I., Gourain, A., Cheize, M., Monin, L., André, L., Laha, P., Terryn, H., and Dehairs, F.: Particulate barium tracing of significant mesopelagic carbon remineralisation in the North Atlantic, Biogeosciences, 15, 2289–2307, https://doi.org/10.5194/bg-15-2289-2018, 2018.
Maiti, K., Charette, M. A., Buesseler, K. O., and Kahru, M.: An inverse
relationship between production and export efficiency in the Southern Ocean,
Geophys. Res. Lett., 40, 1557–1561, https://doi.org/10.1002/GRL.50219, 2013.
Marsay, C. M., Sanders, R. J., Henson, S. A., Pabortsava, K., Achterberg,
E. P., and Lampitt, R. S.: Attenuation of sinking particulate organic carbon
flux through the mesopelagic ocean, P. Natl. Acad. Sci. USA, 112,
1089–1094, https://doi.org/10.1073/pnas.1415311112, 2015.
McDonnell, A. M. P. and Buesseler, K. O.: Variability in the average sinking
velocity of marine particles, Limnol. Oceanogr., 55, 2085–2096,
https://doi.org/10.4319/LO.2010.55.5.2085, 2010.
Mendes, C. R. B., Kerr, R., Tavano, V. M., Cavalheiro, F. A., Garcia, C. A.
E., Gauns Dessai, D. R., and Anilkumar, N.: Cross-front phytoplankton
pigments and chemotaxonomic groups in the Indian sector of the Southern
Ocean, Deep-Sea Res. Pt. II, 118, 221–232,
https://doi.org/10.1016/j.dsr2.2015.01.003, 2015.
Morris, P. J., Sanders, R., Turnewitsch, R., and Thomalla, S.: 234Th-derived
particulate organic carbon export from an island-induced phytoplankton bloom
in the Southern Ocean, Deep-Sea Res. Pt. II,
54, 2208–2232, https://doi.org/10.1016/J.DSR2.2007.06.002, 2007.
Nissen, C., Vogt, M., Münnich, M., Gruber, N., and Haumann, F. A.: Factors controlling coccolithophore biogeography in the Southern Ocean, Biogeosciences, 15, 6997–7024, https://doi.org/10.5194/bg-15-6997-2018, 2018.
Orsi, A. H., Whitworth, T., and Nowlin, W. D.: On the meridional extent and
fronts of the Antarctic Circumpolar Current, Deep-Sea Res. Pt. I, 42,
641–673, https://doi.org/10.1016/0967-0637(95)00021-W, 1995.
Passow, U. and Carlson, C. A.: The biological pump in a high CO2 world,
Mar. Ecol. Prog. Ser., 470, 249–271, https://doi.org/10.3354/meps09985, 2012.
Petrou, K., Kranz, S. A., Trimborn, S., Hassler, C. S., Ameijeiras, S. B.,
Sackett, O., Ralph, P. J., and Davidson, A. T.: Southern Ocean phytoplankton
physiology in a changing climate, J. Plant Physiol., 203, 135–150,
https://doi.org/10.1016/j.jplph.2016.05.004, 2016.
Planchon, F., Cavagna, A.-J., Cardinal, D., André, L., and Dehairs, F.: Late summer particulate organic carbon export and twilight zone remineralisation in the Atlantic sector of the Southern Ocean, Biogeosciences, 10, 803–820, https://doi.org/10.5194/bg-10-803-2013, 2013.
Planquette, H. and Sherrell, R. M.: Sampling for particulate trace element
determination using water sampling bottles: Methodology and comparison to in
situ pumps, Limnol. Oceanogr.-Meth., 10, 367–388,
https://doi.org/10.4319/lom.2012.10.367, 2012.
Pollard, R. T., Lucas, M. I., and Read, J. F.: Physical controls on
biogeochemical zonation in the Southern Ocean, Deep-Sea Res. Pt. II, 49, 3289–3305, https://doi.org/10.1016/S0967-0645(02)00084-X, 2002.
Pyle, K. M., Hendry, K. R., Sherrell, R. M., Legge, O., Hind, A. J.,
Bakker, D., Venables, H., and Meredith, M. P.: Oceanic fronts control the
distribution of dissolved barium in the Southern Ocean, Mar. Chem.,
204, 95–106, https://doi.org/10.1016/j.marchem.2018.07.002, 2018.
Rembauville, M., Briggs, N., Ardyna, M., Uitz, J., Catala, P., Penkerc'h,
C., Poteau, A., Claustre, H., and Blain, S.: Plankton Assemblage Estimated
with BGC-Argo Floats in the Southern Ocean: Implications for Seasonal
Successions and Particle Export, J. Geophys. Res.-Oceans, 122,
8278–8292, https://doi.org/10.1002/2017JC013067, 2017.
Riebesell, U.: Particle aggregation during a diatom bloom, II. Biological
aspects, Mar. Ecol. Prog. Ser., 69, 281–291, https://doi.org/10.3354/meps069281,
1991.
Rio, M. H., Guinehut, S., and Larnicol, G.: New CNES-CLS09 global mean
dynamic topography computed from the combination of GRACE data, altimetry,
and in situ measurements, J. Geophys. Res.-Oceans, 116, 1–25,
https://doi.org/10.1029/2010JC006505, 2011.
Robinson, C., Steinberg, D. K., Anderson, T. R., Arístegui, J.,
Carlson, C. A., Frost, J. R., Ghiglione, J. F., Hernández-León, S.,
Jackson, G. A., Koppelmann, R., Quéguiner, B., Ragueneau, O.,
Rassoulzadegan, F., Robison, B. H., Tamburini, C., Tanaka, T., Wishner, K.
F., and Zhang, J.: Mesopelagic zone ecology and biogeochemistry – A
synthesis, Deep-Sea Res. Pt. II, 57, 1504–1518,
https://doi.org/10.1016/j.dsr2.2010.02.018, 2010.
Rosengard, S. Z., Lam, P. J., Balch, W. M., Auro, M. E., Pike, S., Drapeau, D., and Bowler, B.: Carbon export and transfer to depth across the Southern Ocean Great Calcite Belt, Biogeosciences, 12, 3953–3971, https://doi.org/10.5194/bg-12-3953-2015, 2015.
Rutgers van der Loeff, M. M., Cai, P. H., Stimac, I., Bracher, A.,
Middag, R., Klunder, M. B., and van Heuven, S. M. A. C.: 234Th in surface
waters: Distribution of particle export flux across the Antarctic
Circumpolar Current and in the Weddell Sea during the GEOTRACES expedition
ZERO and DRAKE, Deep-Sea Res. Pt. II, 58,
2749–2766, https://doi.org/10.1016/j.dsr2.2011.02.004, 2011.
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.
Sarmiento, J. and Gruber, N.: Ocean Biogeochemical Dynamics, Princeton
University Press, Princeton, Oxford, https://doi.org/10.2307/j.ctt3fgxqx, 2006.
Sathyendranath, S., Brewin, R. J. W., Brockmann, C., Brotas, V., Calton,
B., Chuprin, A., Cipollini, P., Couto, A. B., Dingle, J., Doerffer, R.,
Donlon, C., Dowell, M., Farman, A., Grant, M., Groom, S., Horseman, A.,
Jackson, T., Krasemann, H., Lavender, S., Martinez-Vicente, V., Mazeran, C.,
Mélin, F., Moore, T. S., Müller, D., Regner, P., Roy, S., Steele, C.
J., Steinmetz, F., Swinton, J., Taberner, M., Thompson, A., Valente, A.,
Zühlke, M., Brando, V. E., Feng, H., Feldman, G., Franz, B. A., Frouin,
R., Gould, R. W., Hooker, S. B., Kahru, M., Kratzer, S., Mitchell, B. G.,
Muller-Karger, F. E., Sosik, H. M., Voss, K. J., Werdell, J., and Platt, T.:
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.
Savoye, N., Trull, T. W., Jacquet, S. H. M., Navez, J., and Dehairs, F.:
234Th-based export fluxes during a natural iron fertilization experiment in
the Southern Ocean (KEOPS), Deep-Sea Res. Pt. II,
55, 841–855, https://doi.org/10.1016/J.DSR2.2007.12.036, 2008.
Schlitzer, R.: Carbon export fluxes in the Southern Ocean: Results from
inverse modeling and comparison with satellite-based estimates, Deep-Sea Res. Pt. II, 49, 1623–1644,
https://doi.org/10.1016/S0967-0645(02)00004-8, 2002.
Shopova, D., Dehairs, F., and Baeyens, W.: A simple model of biogeochemical
element distribution in the oceanic water column, J. Mar. Syst., 6,
331–344, https://doi.org/10.1016/0924-7963(94)00032-7, 1995.
Sigman, D. M., Hain, M. P., and Haug, G. H.: The polar ocean and glacial
cycles in atmospheric CO2 concentration, Nature, 466, 47–55,
https://doi.org/10.1038/nature09149, 2010.
Sternberg, E., Jeandel, C., Robin, E., and Souhaut, M.: Seasonal cycle of
suspended barite in the mediterranean sea, Geochim. Cosmochim. Ac., 72,
4020–4034, https://doi.org/10.1016/J.GCA.2008.05.043, 2008.
Sternberg, E., Tang, D., Ho, T. Y., Jeandel, C., and Morel, F. M. M.: Barium
uptake and adsorption in diatoms, Geochim. Cosmochim. Ac., 69,
2745–2752, https://doi.org/10.1016/j.gca.2004.11.026, 2005.
Swart, S., Speich, S., Ansorge, I. J., and Lutjeharms, J. R. E.: An
altimetry-based gravest empirical mode south of Africa: 1. Development and
validation, J. Geophys. Res.-Oceans, 115, 1–19,
https://doi.org/10.1029/2009JC005299, 2010.
Takahashi, T., Sweeney, C., Hales, B., Chipman, D. W., Goddard, J. G.,
Newberger, T., Iannuzzi, R. A., and Sutherland, S. C.: The changing carbon
cycle in the southern ocean, Oceanography, 25, 26–37,
https://doi.org/10.5670/oceanog.2012.71, 2012.
Taylor, S. R. and McLennan, S. M.: The continental crust: Its composition
and evolution, Blackwell Scientific Pub., Palo Alto, CA, United States,
https://www.osti.gov/biblio/6582885 (last access: 6 October 2020), 1985.
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.
Trull, T. W., Passmore, A., Davies, D. M., Smit, T., Berry, K., and Tilbrook, B.: Distribution of planktonic biogenic carbonate organisms in the Southern Ocean south of Australia: a baseline for ocean acidification impact assessment, Biogeosciences, 15, 31–49, https://doi.org/10.5194/bg-15-31-2018, 2018.
Twining, B. S., Nodder, S. D., King, A. L., Hutchins, D. A., LeCleir, G.
R., DeBruyn, J. M., Maas, E. W., Vogt, S., Wilhelm, S. W., and Boyd, P. W.:
Differential remineralization of major and trace elements in sinking
diatoms, Limnol. Oceanogr., 59, 689–704,
https://doi.org/10.4319/lo.2014.59.3.0689, 2014.
van Beek, P., François, R., Conte, M., Reyss, J. L., Souhaut, M., and
Charette, M.: 228Ra
van Horsten, N. R., Planquette, H., Sarthou, G., Ryan-Keogh, T. J., Lemaitre, N., Mtshali, T. N., Roychoudhury, A., and Bucciarelli, E.: Early winter barium excess in the Southern Indian Ocean as an annual remineralisation proxy (GEOTRACES GIPr07 cruise), Zenodo [data set], https://doi.org/10.5281/zenodo.6583338, 2022.
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/10.1016/j.dsr.2018.09.006, 2018.
Wright, S. W., van den Enden, R. L., Pearce, I., Davidson, A. T., Scott, F.
J., and Westwood, K. J.: Phytoplankton community structure and stocks in the
Southern Ocean (30–80∘ E) determined by CHEMTAX analysis of HPLC
pigment signatures, Deep-Sea Res. Pt. II, 57,
758–778, https://doi.org/10.1016/j.dsr2.2009.06.015, 2010.
Zhuang, J.: xESMF: Universal Regridder for GeospatialData,
https://github.com/JiaweiZhuang/xESMF (last access: 14 August 2020), 2018.
Short summary
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.
The remineralisation proxy, barite, was measured along 30°E in the southern Indian Ocean during...
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