Articles | Volume 16, issue 21
https://doi.org/10.5194/bg-16-4157-2019
© Author(s) 2019. 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-16-4157-2019
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
05 Nov 2019
Research article |
| 05 Nov 2019
| 05 Nov 2019
Controls on redox-sensitive trace metals in the Mauritanian oxygen minimum zone
Insa Rapp
CORRESPONDING AUTHOR
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
now at: Department of Biology, Dalhousie University, Halifax, Nova
Scotia B3H 4R2, Canada
Christian Schlosser
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
Jan-Lukas Menzel Barraqueta
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
Department of Earth Sciences, Stellenbosch University, Stellenbosch,
7600, South Africa
Bernhard Wenzel
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
Jan Lüdke
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
Jan Scholten
Institute of Geosciences, Christian-Albrechts-Universität zu Kiel (CAU),
Otto-Hahn-Platz 1, 24118 Kiel, Germany
Beat Gasser
International Atomic Energy Agency (IAEA), Environment Laboratories, 4 Quai Antoine 1er, 98012, Monaco
Patrick Reichert
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
Martha Gledhill
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
Marcus Dengler
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
Eric P. Achterberg
Helmholtz Centre for Ocean Research Kiel (GEOMAR), Wischhofstr. 1–3,
24148 Kiel, Germany
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Claudia Frey, Hermann W. Bange, Eric P. Achterberg, Amal Jayakumar, Carolin R. Löscher, Damian L. Arévalo-Martínez, Elizabeth León-Palmero, Mingshuang Sun, Xin Sun, Ruifang C. Xie, Sergey Oleynik, and Bess B. Ward
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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
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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
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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.
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.
Marie Maßmig, Jan Lüdke, Gerd Krahmann, and Anja Engel
Biogeosciences, 17, 215–230, https://doi.org/10.5194/bg-17-215-2020, https://doi.org/10.5194/bg-17-215-2020, 2020
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Little is known about the rates of bacterial element cycling in oxygen minimum zones (OMZs). We measured bacterial production and rates of extracellular hydrolytic enzymes at various in situ oxygen concentrations in the OMZ off Peru. Our field data show unhampered bacterial activity at low oxygen concentrations. Meanwhile bacterial degradation of organic matter substantially contributed to the formation of the OMZ.
Tim Fischer, Annette Kock, Damian L. Arévalo-Martínez, Marcus Dengler, Peter Brandt, and Hermann W. Bange
Biogeosciences, 16, 2307–2328, https://doi.org/10.5194/bg-16-2307-2019, https://doi.org/10.5194/bg-16-2307-2019, 2019
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We investigated air–sea gas exchange in oceanic upwelling regions for the case of nitrous oxide off Peru. In this region, routine concentration measurements from ships at 5 m or 10 m depth prove to overestimate surface (bulk) concentration. Thus, standard estimates of gas exchange will show systematic error. This is due to very shallow stratified layers that inhibit exchange between surface water and waters below and can exist for several days. Maximum bias occurs in moderate wind conditions.
Alexandra N. Loginova, Sören Thomsen, Marcus Dengler, Jan Lüdke, and Anja Engel
Biogeosciences, 16, 2033–2047, https://doi.org/10.5194/bg-16-2033-2019, https://doi.org/10.5194/bg-16-2033-2019, 2019
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High primary production in the Peruvian upwelling system is followed by rapid heterotrophic utilization of organic matter and supports the formation of one of the most intense oxygen minimum zones (OMZs) in the world. Here, we estimated vertical fluxes of oxygen and dissolved organic matter (DOM) from the surface to the OMZ. Our results suggest that DOM remineralization substantially reduces oxygen concentration in the upper water column and controls the shape of the upper oxycline.
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.
Joonas J. Virtasalo, Jan F. Schröder, Samrit Luoma, Juha Majaniemi, Juha Mursu, and Jan Scholten
Solid Earth, 10, 405–423, https://doi.org/10.5194/se-10-405-2019, https://doi.org/10.5194/se-10-405-2019, 2019
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This study establishes the local stratigraphy and 3-D aquifer geometry of a submarine groundwater discharge site in the Hanko Peninsula, south Finland. The study is based on a rich dataset of marine seismic profiles, multibeam and side-scan sonar images of the seafloor, and onshore ground-penetrating radar and refraction seismic profiles. The groundwater discharge takes place through metre-scale pockmarks on the seafloor, confirmed by elevated radon concentrations in the overlying water.
Soeren Thomsen, Johannes Karstensen, Rainer Kiko, Gerd Krahmann, Marcus Dengler, and Anja Engel
Biogeosciences, 16, 979–998, https://doi.org/10.5194/bg-16-979-2019, https://doi.org/10.5194/bg-16-979-2019, 2019
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Physical and biogeochemical observations from an autonomous underwater vehicle in combination with ship-based measurements are used to investigate remote and local drivers of the oxygen and nutrient variability off Mauritania. Beside the transport of oxygen and nutrients characteristics from remote areas towards Mauritania also local remineralization of organic material close to the seabed seems to be important for the distribution of oxygen and nutrients.
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.
Joonas J. Virtasalo, Jan F. Schröder, Samrit Luoma, Juha Majaniemi, Juha Mursu, and Jan Scholten
Hydrol. Earth Syst. Sci. Discuss., https://doi.org/10.5194/hess-2018-507, https://doi.org/10.5194/hess-2018-507, 2018
Preprint withdrawn
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Submarine groundwater discharge (SGD) is a significant source of nutrients and other potentially harmful substances to coastal sea. We analyse a rich dataset of offshore seismic sub-bottom profiles, multibeam and sidescan sonar images of seafloor, and onshore ground-penetrating radar profiles to establish the geometry of an SGD site in south Finland. The SGD takes place through meter scale pits (pockmarks) on the seafloor, confirmed by elevated radon concentrations in the overlying water.
Jan-Lukas Menzel Barraqueta, Christian Schlosser, Hélène Planquette, Arthur Gourain, Marie Cheize, Julia Boutorh, Rachel Shelley, Leonardo Contreira Pereira, Martha Gledhill, Mark J. Hopwood, François Lacan, Pascale Lherminier, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 15, 5271–5286, https://doi.org/10.5194/bg-15-5271-2018, https://doi.org/10.5194/bg-15-5271-2018, 2018
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In the North Atlantic and Labrador Sea, low aerosol deposition and enhanced primary productivity control the dissolved aluminium (dAl) surface distribution, while remineralization of particles seems to control the distribution at depth. DAl in the ocean allows us to indirectly quantify the amount of dust deposited to a given region for a given period. Hence, the study of its distribution, cycling, sources, and sinks is of major importance to improve aerosol deposition models and climate models.
Christian Schlosser, Katrin Schmidt, Alfred Aquilina, William B. Homoky, Maxi Castrillejo, Rachel A. Mills, Matthew D. Patey, Sophie Fielding, Angus Atkinson, and Eric P. Achterberg
Biogeosciences, 15, 4973–4993, https://doi.org/10.5194/bg-15-4973-2018, https://doi.org/10.5194/bg-15-4973-2018, 2018
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Iron (Fe) emanating from the South Georgia shelf system fuels large phytoplankton blooms downstream of the island. However, the actual supply mechanisms of Fe are unclear. We found that shelf-sediment-derived iron and iron released from Antarctic krill control the Fe distribution in the shelf waters around South Georgia. The majority of the Fe appears to be derived from recycling of Fe-enriched particles that are transported with the water masses into the bloom region.
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.
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.
Thomas Hornick, Lennart T. Bach, Katharine J. Crawfurd, Kristian Spilling, Eric P. Achterberg, Jason N. Woodhouse, Kai G. Schulz, Corina P. D. Brussaard, Ulf Riebesell, and Hans-Peter Grossart
Biogeosciences, 14, 1–15, https://doi.org/10.5194/bg-14-1-2017, https://doi.org/10.5194/bg-14-1-2017, 2017
Kristian Spilling, Kai G. Schulz, Allanah J. Paul, Tim Boxhammer, Eric P. Achterberg, Thomas Hornick, Silke Lischka, Annegret Stuhr, Rafael Bermúdez, Jan Czerny, Kate Crawfurd, Corina P. D. Brussaard, Hans-Peter Grossart, and Ulf Riebesell
Biogeosciences, 13, 6081–6093, https://doi.org/10.5194/bg-13-6081-2016, https://doi.org/10.5194/bg-13-6081-2016, 2016
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We performed an experiment in the Baltic Sea in order to investigate the consequences of the increasing CO2 levels on biological processes in the free water mass. There was more accumulation of organic carbon at high CO2 levels. Surprisingly, this was caused by reduced loss processes (respiration and bacterial production) in a high-CO2 environment, and not by increased photosynthetic fixation of CO2. Our carbon budget can be used to better disentangle the effects of ocean acidification.
Allanah J. Paul, Eric P. Achterberg, Lennart T. Bach, Tim Boxhammer, Jan Czerny, Mathias Haunost, Kai-Georg Schulz, Annegret Stuhr, and Ulf Riebesell
Biogeosciences, 13, 3901–3913, https://doi.org/10.5194/bg-13-3901-2016, https://doi.org/10.5194/bg-13-3901-2016, 2016
Matthew P. Humphreys, Florence M. Greatrix, Eithne Tynan, Eric P. Achterberg, Alex M. Griffiths, Claudia H. Fry, Rebecca Garley, Alison McDonald, and Adrian J. Boyce
Earth Syst. Sci. Data, 8, 221–233, https://doi.org/10.5194/essd-8-221-2016, https://doi.org/10.5194/essd-8-221-2016, 2016
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This paper reports the stable isotope composition of dissolved inorganic carbon in seawater for a transect from west to east across the North Atlantic Ocean. The results can be used to study oceanic uptake of anthropogenic carbon dioxide, and also to investigate the natural biological carbon pump. We also provide stable DIC isotope results for two batches of Dickson seawater CRMs to enable intercomparisons with other studies.
Monika Nausch, Lennart Thomas Bach, Jan Czerny, Josephine Goldstein, Hans-Peter Grossart, Dana Hellemann, Thomas Hornick, Eric Pieter Achterberg, Kai-Georg Schulz, and Ulf Riebesell
Biogeosciences, 13, 3035–3050, https://doi.org/10.5194/bg-13-3035-2016, https://doi.org/10.5194/bg-13-3035-2016, 2016
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Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. Therefore, we conducted a CO2-manipulation mesocosm experiment in the Storfjärden (western Gulf of Finland, Baltic Sea) in summer 2012. We compared the phosphorus dynamics in different mesocosm treatment
Lorenzo Rovelli, Marcus Dengler, Mark Schmidt, Stefan Sommer, Peter Linke, and Daniel F. McGinnis
Biogeosciences, 13, 1609–1620, https://doi.org/10.5194/bg-13-1609-2016, https://doi.org/10.5194/bg-13-1609-2016, 2016
R. Steinfeldt, J. Sültenfuß, M. Dengler, T. Fischer, and M. Rhein
Biogeosciences, 12, 7519–7533, https://doi.org/10.5194/bg-12-7519-2015, https://doi.org/10.5194/bg-12-7519-2015, 2015
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The coastal upwelling systems, e.g. off Peru and Mauritania,
are key regions for the emissions of climate relevant trace gases
from the ocean into the atmosphere. Here, gases and nutrients are
transported into the ocean mixed layer from below. The upwelling velocities,
however, are too small to be measured directly.
We use the enhancement of helium-3 in upwelled
waters to quantify the vertical velocity,
which varies between 1.0 and 2.5 metres per day in the coastal regions.
A. J. Paul, L. T. Bach, K.-G. Schulz, T. Boxhammer, J. Czerny, E. P. Achterberg, D. Hellemann, Y. Trense, M. Nausch, M. Sswat, and U. Riebesell
Biogeosciences, 12, 6181–6203, https://doi.org/10.5194/bg-12-6181-2015, https://doi.org/10.5194/bg-12-6181-2015, 2015
Y. Zhang, N. Mahowald, R. A. Scanza, E. Journet, K. Desboeufs, S. Albani, J. F. Kok, G. Zhuang, Y. Chen, D. D. Cohen, A. Paytan, M. D. Patey, E. P. Achterberg, J. P. Engelbrecht, and K. W. Fomba
Biogeosciences, 12, 5771–5792, https://doi.org/10.5194/bg-12-5771-2015, https://doi.org/10.5194/bg-12-5771-2015, 2015
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A new technique to determine a size-fractionated global soil elemental emission inventory based on a global soil and mineralogical data set is introduced. Spatial variability of mineral dust elemental fractions (8 elements, e.g., Ca, Fe, Al) is identified on a global scale, particularly for Ca. The Ca/Al ratio ranged between 0.1 and 5.0 and is confirmed as an indicator of dust source regions by a global dust model. Total and soluble dust element fluxes into different ocean basins are estimated.
J.-C. Miquel, B. Gasser, J. Martín, C. Marec, M. Babin, L. Fortier, and A. Forest
Biogeosciences, 12, 5103–5117, https://doi.org/10.5194/bg-12-5103-2015, https://doi.org/10.5194/bg-12-5103-2015, 2015
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POC fluxes obtained in the Eastern Beaufort Sea in August 2009 from drifting sediment traps were low (1-15 mg C m-2d-1), compared to long-term data which show higher but variable fluxes (10-40 mg C m-2d-1).
Composition of sinking particles, especially faecal pellets, highlighted the role of the zooplankton community and its trophic structure in the transition of carbon from the productive surface zone to the deep ocean. Carbon flux at this season results from a heterotrophic driven ecosystem.
M. P. Humphreys, E. P. Achterberg, A. M. Griffiths, A. McDonald, and A. J. Boyce
Earth Syst. Sci. Data, 7, 127–135, https://doi.org/10.5194/essd-7-127-2015, https://doi.org/10.5194/essd-7-127-2015, 2015
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We present measurements of the stable carbon isotope composition of seawater dissolved inorganic carbon. The samples were collected during two research cruises in boreal summer 2012 in the northeastern Atlantic and Nordic Seas. The results can be used to investigate the marine carbon cycle, providing information about biological productivity and oceanic uptake of anthropogenic carbon dioxide.
A. W. Dale, S. Sommer, U. Lomnitz, I. Montes, T. Treude, V. Liebetrau, J. Gier, C. Hensen, M. Dengler, K. Stolpovsky, L. D. Bryant, and K. Wallmann
Biogeosciences, 12, 1537–1559, https://doi.org/10.5194/bg-12-1537-2015, https://doi.org/10.5194/bg-12-1537-2015, 2015
P. Brandt, H. W. Bange, D. Banyte, M. Dengler, S.-H. Didwischus, T. Fischer, R. J. Greatbatch, J. Hahn, T. Kanzow, J. Karstensen, A. Körtzinger, G. Krahmann, S. Schmidtko, L. Stramma, T. Tanhua, and M. Visbeck
Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, https://doi.org/10.5194/bg-12-489-2015, 2015
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Our observational study looks at the structure of the eastern tropical North Atlantic (ETNA) oxygen minimum zone (OMZ) in comparison with the less-ventilated, eastern tropical South Pacific OMZ. We quantify the OMZ’s oxygen budget composed of consumption, advection, lateral and vertical mixing. Substantial oxygen variability is observed on interannual to multidecadal timescales. The deoxygenation of the ETNA OMZ during the last decades represents a substantial imbalance of the oxygen budget.
T. J. Browning, H. A. Bouman, C. M. Moore, C. Schlosser, G. A. Tarran, E. M. S. Woodward, and G. M. Henderson
Biogeosciences, 11, 463–479, https://doi.org/10.5194/bg-11-463-2014, https://doi.org/10.5194/bg-11-463-2014, 2014
T. Fischer, D. Banyte, P. Brandt, M. Dengler, G. Krahmann, T. Tanhua, and M. Visbeck
Biogeosciences, 10, 5079–5093, https://doi.org/10.5194/bg-10-5079-2013, https://doi.org/10.5194/bg-10-5079-2013, 2013
A. Forest, M. Babin, L. Stemmann, M. Picheral, M. Sampei, L. Fortier, Y. Gratton, S. Bélanger, E. Devred, J. Sahlin, D. Doxaran, F. Joux, E. Ortega-Retuerta, J. Martín, W. H. Jeffrey, B. Gasser, and J. Carlos Miquel
Biogeosciences, 10, 2833–2866, https://doi.org/10.5194/bg-10-2833-2013, https://doi.org/10.5194/bg-10-2833-2013, 2013
Related subject area
Biogeochemistry: Coastal Ocean
Long-term variations in pH in coastal waters along the Korean Peninsula
The effect of carbonate mineral additions on biogeochemical conditions in surface sediments and benthic–pelagic exchange fluxes
Assessing the impacts of simulated ocean alkalinity enhancement on viability and growth of nearshore species of phytoplankton
Responses of microbial metabolic rates to non-equilibrated silicate- versus calcium-based ocean alkalinity enhancement
High metabolic zinc demand within native Amundsen and Ross sea phytoplankton communities determined by stable isotope uptake rate measurements
The influence of zooplankton and oxygen on the particulate organic carbon flux in the Benguela Upwelling System
Reviews and syntheses: Biological indicators of low-oxygen stress in marine water-breathing animals
Temperature-enhanced effects of iron on Southern Ocean phytoplankton
Riverine nutrient impact on global ocean nitrogen cycle feedbacks and marine primary production in an Earth system model
The Northeast Greenland Shelf as a potential late-summer CO2 source to the atmosphere
Technical note: Ocean Alkalinity Enhancement Pelagic Impact Intercomparison Project (OAEPIIP)
Estimates of carbon sequestration potential in an expanding Arctic fjord (Hornsund, Svalbard) affected by dark plumes of glacial meltwater
An assessment of ocean alkalinity enhancement using aqueous hydroxides: kinetics, efficiency, and precipitation thresholds
Dissolved nitric oxide in the lower Elbe Estuary and the Port of Hamburg area
The bacteria-protist link as a main route of dissolved organic matter across contrasting productivity areas in the Patagonian Shelf
Technical note: New approach for the determination of N2 fixation rates by coupling a membrane equilibrator to a mass spectrometer on voluntary observing ships
Variable contribution of wastewater treatment plant effluents to downstream nitrous oxide concentrations and emissions
Distribution of nutrients and dissolved organic matter in a eutrophic equatorial estuary: the Johor River and the East Johor Strait
Investigating the effect of silicate- and calcium-based ocean alkalinity enhancement on diatom silicification
Ocean alkalinity enhancement using sodium carbonate salts does not lead to measurable changes in Fe dynamics in a mesocosm experiment
Quantification and mitigation of bottom-trawling impacts on sedimentary organic carbon stocks in the North Sea
Influence of ocean alkalinity enhancement with olivine or steel slag on a coastal plankton community in Tasmania
Reviews and synthesis: increasing hypoxia in eastern boundary upwelling systems: a major stressor for zooplankton
Multi-model comparison of trends and controls of near-bed oxygen concentration on the northwest European continental shelf under climate change
Picoplanktonic methane production in eutrophic surface waters
Vertical mixing alleviates autumnal oxygen deficiency in the central North Sea
Hypoxia also occurs in small highly turbid estuaries: the example of the Charente (Bay of Biscay)
Seasonality and response of ocean acidification and hypoxia to major environmental anomalies in the southern Salish Sea, North America (2014–2018)
Ocean Alkalinity Enhancement (OAE) does not cause cellular stress in a phytoplankton community of the sub-tropical Atlantic Ocean
Oceanographic processes driving low-oxygen conditions inside Patagonian fjords
Above- and belowground plant mercury dynamics in a salt marsh estuary in Massachusetts, USA
Variability and drivers of carbonate chemistry at shellfish aquaculture sites in the Salish Sea, British Columbia
Unusual Hemiaulus bloom influences ocean productivity in Northeastern US Shelf waters
Insights into carbonate environmental conditions in the Chukchi Sea
UAV approaches for improved mapping of vegetation cover and estimation of carbon storage of small saltmarshes: examples from Loch Fleet, northeast Scotland
Iron “ore” nothing: benthic iron fluxes from the oxygen-deficient Santa Barbara Basin enhance phytoplankton productivity in surface waters
Marine anoxia initiates giant sulfur-oxidizing bacterial mat proliferation and associated changes in benthic nitrogen, sulfur, and iron cycling in the Santa Barbara Basin, California Borderland
Uncertainty in the evolution of northwestern North Atlantic circulation leads to diverging biogeochemical projections
The additionality problem of ocean alkalinity enhancement
Short-term variation in pH in seawaters around coastal areas of Japan: characteristics and forcings
Revisiting the applicability and constraints of molybdenum- and uranium-based paleo redox proxies: comparing two contrasting sill fjords
Influence of a small submarine canyon on biogenic matter export flux in the lower St. Lawrence Estuary, eastern Canada
Single-celled bioturbators: benthic foraminifera mediate oxygen penetration and prokaryotic diversity in intertidal sediment
Assessing impacts of coastal warming, acidification, and deoxygenation on Pacific oyster (Crassostrea gigas) farming: a case study in the Hinase area, Okayama Prefecture, and Shizugawa Bay, Miyagi Prefecture, Japan
Multiple nitrogen sources for primary production inferred from δ13C and δ15N in the southern Sea of Japan
Influence of manganese cycling on alkalinity in the redox stratified water column of Chesapeake Bay
Estuarine flocculation dynamics of organic carbon and metals from boreal acid sulfate soils
Drivers of particle sinking velocities in the Peruvian upwelling system
Impacts and uncertainties of climate-induced changes in watershed inputs on estuarine hypoxia
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed
Yong-Woo Lee, Mi-Ok Park, Seong-Gil Kim, Tae-Hoon Kim, Yong Hwa Oh, Sang Heon Lee, and DongJoo Joung
Biogeosciences, 22, 675–690, https://doi.org/10.5194/bg-22-675-2025, https://doi.org/10.5194/bg-22-675-2025, 2025
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Long-term pH variation in coastal waters along the Korean Peninsula was assessed for the first time, and it exhibited no significant pH change over an 11-year period. This contrasts with the ongoing pH decline in open oceans and other coastal areas. Analysis of environmental data showed that pH is mainly controlled by dissolved oxygen in bottom waters. This suggests that ocean warming could cause a pH decline in Korean coastal waters, affecting many fish and seaweed aquaculture operations.
Kadir Biçe, Tristen Myers Stewart, George G. Waldbusser, and Christof Meile
Biogeosciences, 22, 641–657, https://doi.org/10.5194/bg-22-641-2025, https://doi.org/10.5194/bg-22-641-2025, 2025
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We studied the effect of addition of carbonate minerals on coastal sediments. We carried out laboratory experiments to quantify the dissolution kinetics and integrated these observations into a numerical model that describes biogeochemical cycling in surficial sediments. Using the model, we demonstrate the buffering effect of the mineral additions and their duration. We quantify the effect under different environmental conditions and assess the potential for increased atmospheric CO2 uptake.
Jessica L. Oberlander, Mackenzie E. Burke, Cat A. London, and Hugh L. MacIntyre
Biogeosciences, 22, 499–512, https://doi.org/10.5194/bg-22-499-2025, https://doi.org/10.5194/bg-22-499-2025, 2025
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Ocean alkalinity enhancement (OAE) is a promising negative emission technology that results in the net sequestration of atmospheric carbon. In this paper, we assess the potential impact of OAE on phytoplankton through an analysis of prior studies and the effects of simulated OAE on photosynthetic competence. Our findings suggest that there may be little if any significant impact on most phytoplankton studied to date if OAE is conducted in well-flushed, nearshore environments.
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, and Ulf Riebesell
Biogeosciences, 21, 5707–5724, https://doi.org/10.5194/bg-21-5707-2024, https://doi.org/10.5194/bg-21-5707-2024, 2024
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This study exposed a natural community to two non-CO2-equilibrated ocean alkalinity enhancement (OAE) deployments using different minerals. Adding alkalinity in this manner decreases dissolved CO2, essential for photosynthesis. While photosynthesis was not suppressed, bloom formation was mildly delayed, potentially impacting marine food webs. The study emphasizes the need for further research on OAE without prior equilibration and on its ecological implications.
Riss M. Kell, Rebecca J. Chmiel, Deepa Rao, Dawn M. Moran, Matthew R. McIlvin, Tristan J. Horner, Nicole L. Schanke, Ichiko Sugiyama, Robert B. Dunbar, Giacomo R. DiTullio, and Mak A. Saito
Biogeosciences, 21, 5685–5706, https://doi.org/10.5194/bg-21-5685-2024, https://doi.org/10.5194/bg-21-5685-2024, 2024
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Despite interest in modeling the biogeochemical uptake and cycling of the trace metal zinc (Zn), measurements of Zn uptake in natural marine phytoplankton communities have not been conducted previously. To fill this gap, we employed a stable isotope uptake rate measurement method to quantify Zn uptake into natural phytoplankton assemblages within the Southern Ocean. Zn demand was high and rapid enough to depress the inventory of Zn available to phytoplankton on seasonal timescales.
Luisa Chiara Meiritz, Tim Rixen, Anja Karin van der Plas, Tarron Lamont, and Niko Lahajnar
Biogeosciences, 21, 5261–5276, https://doi.org/10.5194/bg-21-5261-2024, https://doi.org/10.5194/bg-21-5261-2024, 2024
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Moored and drifting sediment trap experiments in the northern (nBUS) and southern (sBUS) Benguela Upwelling System showed that active carbon fluxes by vertically migrating zooplankton were about 3 times higher in the sBUS than in the nBUS. Despite these large variabilities, the mean passive particulate organic carbon (POC) fluxes were almost equal in the two subsystems. The more intense near-bottom oxygen minimum layer seems to lead to higher POC fluxes and accumulation rates in the nBUS.
Michael R. Roman, Andrew H. Altieri, Denise Breitburg, Erica M. Ferrer, Natalya D. Gallo, Shin-ichi Ito, Karin Limburg, Kenneth Rose, Moriaki Yasuhara, and Lisa A. Levin
Biogeosciences, 21, 4975–5004, https://doi.org/10.5194/bg-21-4975-2024, https://doi.org/10.5194/bg-21-4975-2024, 2024
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Oxygen-depleted ocean waters have increased worldwide. In order to improve our understanding of the impacts of this oxygen loss on marine life it is essential that we develop reliable indicators that track the negative impacts of low oxygen. We review various indicators of low-oxygen stress for marine animals including their use, research needs, and application to confront the challenges of ocean oxygen loss.
Charlotte Eich, Mathijs van Manen, J. Scott P. McCain, Loay J. Jabre, Willem H. van de Poll, Jinyoung Jung, Sven B. E. H. Pont, Hung-An Tian, Indah Ardiningsih, Gert-Jan Reichart, Erin M. Bertrand, Corina P. D. Brussaard, and Rob Middag
Biogeosciences, 21, 4637–4663, https://doi.org/10.5194/bg-21-4637-2024, https://doi.org/10.5194/bg-21-4637-2024, 2024
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Phytoplankton growth in the Southern Ocean (SO) is often limited by low iron (Fe) concentrations. Sea surface warming impacts Fe availability and can affect phytoplankton growth. We used shipboard Fe clean incubations to test how changes in Fe and temperature affect SO phytoplankton. Their abundances usually increased with Fe addition and temperature increase, with Fe being the major factor. These findings imply potential shifts in ecosystem structure, impacting food webs and elemental cycling.
Miriam Tivig, David P. Keller, and Andreas Oschlies
Biogeosciences, 21, 4469–4493, https://doi.org/10.5194/bg-21-4469-2024, https://doi.org/10.5194/bg-21-4469-2024, 2024
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Marine biological production is highly dependent on the availability of nitrogen and phosphorus. Rivers are the main source of phosphorus to the oceans but poorly represented in global model oceans. We include dissolved nitrogen and phosphorus from river export in a global model ocean and find that the addition of riverine phosphorus affects marine biology on millennial timescales more than riverine nitrogen alone. Globally, riverine phosphorus input increases primary production rates.
Esdoorn Willcox, Marcos Lemes, Thomas Juul-Pedersen, Mikael Kristian Sejr, Johnna Marchiano Holding, and Søren Rysgaard
Biogeosciences, 21, 4037–4050, https://doi.org/10.5194/bg-21-4037-2024, https://doi.org/10.5194/bg-21-4037-2024, 2024
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In this work, we measured the chemistry of seawater from samples obtained from different depths and locations off the east coast of the Northeast Greenland National Park to determine what is influencing concentrations of dissolved CO2. Historically, the region has always been thought to take up CO2 from the atmosphere, but we show that it is possible for the region to become a source in late summer. We discuss the variables that may be related to such changes.
Lennart Thomas Bach, Aaron James Ferderer, Julie LaRoche, and Kai Georg Schulz
Biogeosciences, 21, 3665–3676, https://doi.org/10.5194/bg-21-3665-2024, https://doi.org/10.5194/bg-21-3665-2024, 2024
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Ocean alkalinity enhancement (OAE) is an emerging marine CO2 removal method, but its environmental effects are insufficiently understood. The OAE Pelagic Impact Intercomparison Project (OAEPIIP) provides funding for a standardized and globally replicated microcosm experiment to study the effects of OAE on plankton communities. Here, we provide a detailed manual for the OAEPIIP experiment. We expect OAEPIIP to help build scientific consensus on the effects of OAE on plankton.
Marlena Szeligowska, Déborah Benkort, Anna Przyborska, Mateusz Moskalik, Bernabé Moreno, Emilia Trudnowska, and Katarzyna Błachowiak-Samołyk
Biogeosciences, 21, 3617–3639, https://doi.org/10.5194/bg-21-3617-2024, https://doi.org/10.5194/bg-21-3617-2024, 2024
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The European Arctic is experiencing rapid regional warming, causing glaciers that terminate in the sea to retreat onto land. Due to this process, the area of a well-studied fjord, Hornsund, has increased by around 100 km2 (40%) since 1976. Combining satellite and in situ data with a mathematical model, we estimated that, despite some negative consequences of glacial meltwater release, such emerging coastal waters could mitigate climate change by increasing carbon uptake and storage by sediments.
Mallory C. Ringham, Nathan Hirtle, Cody Shaw, Xi Lu, Julian Herndon, Brendan R. Carter, and Matthew D. Eisaman
Biogeosciences, 21, 3551–3570, https://doi.org/10.5194/bg-21-3551-2024, https://doi.org/10.5194/bg-21-3551-2024, 2024
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Ocean alkalinity enhancement leverages the large surface area and carbon storage capacity of the oceans to store atmospheric CO2 as dissolved bicarbonate. We monitored CO2 uptake in seawater treated with NaOH to establish operational boundaries for carbon removal experiments. Results show that CO2 equilibration occurred on the order of weeks to months, was consistent with values expected from equilibration calculations, and was limited by mineral precipitation at high pH and CaCO3 saturation.
Riel Carlo O. Ingeniero, Gesa Schulz, and Hermann W. Bange
Biogeosciences, 21, 3425–3440, https://doi.org/10.5194/bg-21-3425-2024, https://doi.org/10.5194/bg-21-3425-2024, 2024
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Our research is the first to measure dissolved NO concentrations in temperate estuarine waters, providing insights into its distribution under varying conditions and enhancing our understanding of its production processes. Dissolved NO was supersaturated in the Elbe Estuary, indicating that it is a source of atmospheric NO. The observed distribution of dissolved NO most likely resulted from nitrification.
Celeste López-Abbate, John E. Garzón-Cardona, Ricardo Silva, Juan-Carlos Molinero, Laura A. Ruiz-Etcheverry, Ana M. Martínez, Azul S. Gilabert, and Rubén J. Lara
EGUsphere, https://doi.org/10.5194/egusphere-2024-1860, https://doi.org/10.5194/egusphere-2024-1860, 2024
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This study examines how microbial community structure, growth, and grazing impact the DOM pool in the Patagonian Shelf. Despite higher phytoplankton biomass, faster-growing bacteria were selectively grazed by protists leading to DOM accumulation, likely due to a reduction in DOM-consuming bacteria and the addition of egestion compounds. Experimental data showed that while bacteria remained as the primarily shapers of DOM quality, grazing pressure impacted on DOM accumulation.
Sören Iwe, Oliver Schmale, and Bernd Schneider
EGUsphere, https://doi.org/10.5194/egusphere-2024-2049, https://doi.org/10.5194/egusphere-2024-2049, 2024
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We present a novel method to quantify N2 fixation by cyanobacteria, crucial in Baltic Sea eutrophication. Our Gas Equilibrium – Membrane-Inlet Mass Spectrometer (GE-MIMS), designed for operation on voluntary observing ships (VOS), enables large-scale monitoring of surface water N2 depletion caused by N2 fixation. Laboratory tests confirm the device’s accuracy and precision, ensuring it can complement current methods and contribute valuable data to better understand N2 fixation in the Baltic Sea.
Weiyi Tang, Jeff Talbott, Timothy Jones, and Bess B. Ward
Biogeosciences, 21, 3239–3250, https://doi.org/10.5194/bg-21-3239-2024, https://doi.org/10.5194/bg-21-3239-2024, 2024
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Wastewater treatment plants (WWTPs) are known to be hotspots of greenhouse gas emissions. However, the impact of WWTPs on the emission of the greenhouse gas N2O in downstream aquatic environments is less constrained. We found spatially and temporally variable but overall higher N2O concentrations and fluxes in waters downstream of WWTPs, pointing to the need for efficient N2O removal in addition to the treatment of nitrogen in WWTPs.
Amanda Y. L. Cheong, Kogila Vani Annammala, Ee Ling Yong, Yongli Zhou, Robert S. Nichols, and Patrick Martin
Biogeosciences, 21, 2955–2971, https://doi.org/10.5194/bg-21-2955-2024, https://doi.org/10.5194/bg-21-2955-2024, 2024
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We measured nutrients and dissolved organic matter for 1 year in a eutrophic tropical estuary to understand their sources and cycling. Our data show that the dissolved organic matter originates partly from land and partly from microbial processes in the water. Internal recycling is likely important for maintaining high nutrient concentrations, and we found that there is often excess nitrogen compared to silicon and phosphorus. Our data help to explain how eutrophication persists in this system.
Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, and Lennart T. Bach
Biogeosciences, 21, 2777–2794, https://doi.org/10.5194/bg-21-2777-2024, https://doi.org/10.5194/bg-21-2777-2024, 2024
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Ocean alkalinity enhancement (OAE) is a promising method of atmospheric carbon removal; however, its ecological impacts remain largely unknown. We assessed the effects of simulated silicate- and calcium-based mineral OAE on diatom silicification. We found that increased silicate concentrations from silicate-based OAE increased diatom silicification. In contrast, the enhancement of alkalinity had no effect on community silicification and minimal effects on the silicification of different genera.
David González-Santana, María Segovia, Melchor González-Dávila, Librada Ramírez, Aridane G. González, Leonardo J. Pozzo-Pirotta, Veronica Arnone, Victor Vázquez, Ulf Riebesell, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 2705–2715, https://doi.org/10.5194/bg-21-2705-2024, https://doi.org/10.5194/bg-21-2705-2024, 2024
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In a recent experiment off the coast of Gran Canaria (Spain), scientists explored a method called ocean alkalinization enhancement (OAE), where carbonate minerals were added to seawater. This process changed the levels of certain ions in the water, affecting its pH and buffering capacity. The researchers were particularly interested in how this could impact the levels of essential trace metals in the water.
Lucas Porz, Wenyan Zhang, Nils Christiansen, Jan Kossack, Ute Daewel, and Corinna Schrum
Biogeosciences, 21, 2547–2570, https://doi.org/10.5194/bg-21-2547-2024, https://doi.org/10.5194/bg-21-2547-2024, 2024
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Seafloor sediments store a large amount of carbon, helping to naturally regulate Earth's climate. If disturbed, some sediment particles can turn into CO2, but this effect is not well understood. Using computer simulations, we found that bottom-contacting fishing gears release about 1 million tons of CO2 per year in the North Sea, one of the most heavily fished regions globally. We show how protecting certain areas could reduce these emissions while also benefitting seafloor-living animals.
Jiaying A. Guo, Robert F. Strzepek, Kerrie M. Swadling, Ashley T. Townsend, and Lennart T. Bach
Biogeosciences, 21, 2335–2354, https://doi.org/10.5194/bg-21-2335-2024, https://doi.org/10.5194/bg-21-2335-2024, 2024
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Ocean alkalinity enhancement aims to increase atmospheric CO2 sequestration by adding alkaline materials to the ocean. We assessed the environmental effects of olivine and steel slag powder on coastal plankton. Overall, slag is more efficient than olivine in releasing total alkalinity and, thus, in its ability to sequester CO2. Slag also had less environmental effect on the enclosed plankton communities when considering its higher CO2 removal potential based on this 3-week experiment.
Leissing Frederick, Mauricio A. Urbina, and Ruben Escribano
EGUsphere, https://doi.org/10.5194/egusphere-2024-836, https://doi.org/10.5194/egusphere-2024-836, 2024
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Evidence shows that due to global warming zooplankton inhabiting the coastal upwelling zone are exposed to increasing hypoxia affecting their physiology, metabolism, and population dynamics. The adaptive responses of zooplankton to cope with mild/severe hypoxia may depend on trade-offs with other metabolic/energy-demands, implying less energy for growth, feeding and reproduction with ecological consequences for the zooplankton populations and the marine food web.
Giovanni Galli, Sarah Wakelin, James Harle, Jason Holt, and Yuri Artioli
Biogeosciences, 21, 2143–2158, https://doi.org/10.5194/bg-21-2143-2024, https://doi.org/10.5194/bg-21-2143-2024, 2024
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This work shows that, under a high-emission scenario, oxygen concentration in deep water of parts of the North Sea and Celtic Sea can become critically low (hypoxia) towards the end of this century. The extent and frequency of hypoxia depends on the intensity of climate change projected by different climate models. This is the result of a complex combination of factors like warming, increase in stratification, changes in the currents and changes in biological processes.
Sandy E. Tenorio and Laura Farías
Biogeosciences, 21, 2029–2050, https://doi.org/10.5194/bg-21-2029-2024, https://doi.org/10.5194/bg-21-2029-2024, 2024
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Time series studies show that CH4 is highly dynamic on the coastal ocean surface and planktonic communities are linked to CH4 accumulation, as found in coastal upwelling off Chile. We have identified the crucial role of picoplankton (> 3 µm) in CH4 recycling, especially with the addition of methylated substrates (trimethylamine and methylphosphonic acid) during upwelling and non-upwelling periods. These insights improve understanding of surface ocean CH4 recycling, aiding CH4 emission estimates.
Charlotte A. J. Williams, Tom Hull, Jan Kaiser, Claire Mahaffey, Naomi Greenwood, Matthew Toberman, and Matthew R. Palmer
Biogeosciences, 21, 1961–1971, https://doi.org/10.5194/bg-21-1961-2024, https://doi.org/10.5194/bg-21-1961-2024, 2024
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Oxygen (O2) is a key indicator of ocean health. The risk of O2 loss in the productive coastal/continental slope regions is increasing. Autonomous underwater vehicles equipped with O2 optodes provide lots of data but have problems resolving strong vertical O2 changes. Here we show how to overcome this and calculate how much O2 is supplied to the low-O2 bottom waters via mixing. Bursts in mixing supply nearly all of the O2 to bottom waters in autumn, stopping them reaching ecologically low levels.
Sabine Schmidt and Ibrahima Iris Diallo
Biogeosciences, 21, 1785–1800, https://doi.org/10.5194/bg-21-1785-2024, https://doi.org/10.5194/bg-21-1785-2024, 2024
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Along the French coast facing the Bay of Biscay, the large Gironde and Loire estuaries suffer from hypoxia. This prompted a study of the small Charente estuary located between them. This work reveals a minimum oxygen zone in the Charente estuary, which extends for about 25 km. Temperature is the main factor controlling the hypoxia. This calls for the monitoring of small turbid macrotidal estuaries that are vulnerable to hypoxia, a risk expected to increase with global warming.
Simone R. Alin, Jan A. Newton, Richard A. Feely, Samantha Siedlecki, and Dana Greeley
Biogeosciences, 21, 1639–1673, https://doi.org/10.5194/bg-21-1639-2024, https://doi.org/10.5194/bg-21-1639-2024, 2024
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We provide a new multi-stressor data product that allows us to characterize the seasonality of temperature, O2, and CO2 in the southern Salish Sea and delivers insights into the impacts of major marine heatwave and precipitation anomalies on regional ocean acidification and hypoxia. We also describe the present-day frequencies of temperature, O2, and ocean acidification conditions that cross thresholds of sensitive regional species that are economically or ecologically important.
Librada Ramírez, Leonardo J. Pozzo-Pirotta, Aja Trebec, Víctor Manzanares-Vázquez, José L. Díez, Javier Arístegui, Ulf Riebesell, Stephen D. Archer, and María Segovia
EGUsphere, https://doi.org/10.5194/egusphere-2024-847, https://doi.org/10.5194/egusphere-2024-847, 2024
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We studied the potential effects of increasing ocean alkalinity on a natural plankton community in subtropical waters of the Atlantic near Gran Canaria, Spain. Alkalinity is the capacity of water to resist acidification and plankton are usually microscopic plants (phytoplankton) and animals (zooplankton), often less than 2,5 cm in length. This study suggests that increasing ocean alkalinity did not have a significant negative impact on the studied plankton community.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera, Manuel Castillo, Aida Alvera-Azcárate, Mónica Alvarado, Gabriel Soto, Cécile Pujol, Camila Schwerter, Sara Arenas-Uribe, Pilar Navarro, Guido Mancilla-Gutiérrez, Robinson Altamirano, Javiera San Martín, and Camila Soto-Riquelme
Biogeosciences, 21, 1433–1459, https://doi.org/10.5194/bg-21-1433-2024, https://doi.org/10.5194/bg-21-1433-2024, 2024
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The Patagonian fjords comprise a world region where low-oxygen water and hypoxia conditions are observed. An in situ dataset was used to quantify the mechanism involved in the presence of these conditions in northern Patagonian fjords. Water mass analysis confirmed the contribution of Equatorial Subsurface Water in the advection of the low-oxygen water, and hypoxic conditions occurred when the community respiration rate exceeded the gross primary production.
Ting Wang, Buyun Du, Inke Forbrich, Jun Zhou, Joshua Polen, Elsie M. Sunderland, Prentiss H. Balcom, Celia Chen, and Daniel Obrist
Biogeosciences, 21, 1461–1476, https://doi.org/10.5194/bg-21-1461-2024, https://doi.org/10.5194/bg-21-1461-2024, 2024
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The strong seasonal increases of Hg in aboveground biomass during the growing season and the lack of changes observed after senescence in this salt marsh ecosystem suggest physiologically controlled Hg uptake pathways. The Hg sources found in marsh aboveground tissues originate from a mix of sources, unlike terrestrial ecosystems, where atmospheric GEM is the main source. Belowground plant tissues mostly take up Hg from soils. Overall, the salt marsh currently serves as a small net Hg sink.
Eleanor Simpson, Debby Ianson, Karen E. Kohfeld, Ana C. Franco, Paul A. Covert, Marty Davelaar, and Yves Perreault
Biogeosciences, 21, 1323–1353, https://doi.org/10.5194/bg-21-1323-2024, https://doi.org/10.5194/bg-21-1323-2024, 2024
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Shellfish aquaculture operates in nearshore areas where data on ocean acidification parameters are limited. We show daily and seasonal variability in pH and saturation states of calcium carbonate at nearshore aquaculture sites in British Columbia, Canada, and determine the contributing drivers of this variability. We find that nearshore locations have greater variability than open waters and that the uptake of carbon by phytoplankton is the major driver of pH and saturation state variability.
S. Alejandra Castillo Cieza, Rachel H. R. Stanley, Pierre Marrec, Diana N. Fontaine, E. Taylor Crockford, Dennis J. McGillicuddy Jr., Arshia Mehta, Susanne Menden-Deuer, Emily E. Peacock, Tatiana A. Rynearson, Zoe O. Sandwith, Weifeng Zhang, and Heidi M. Sosik
Biogeosciences, 21, 1235–1257, https://doi.org/10.5194/bg-21-1235-2024, https://doi.org/10.5194/bg-21-1235-2024, 2024
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The coastal ocean in the northeastern USA provides many services, including fisheries and habitats for threatened species. In summer 2019, a bloom occurred of a large unusual phytoplankton, the diatom Hemiaulus, with nitrogen-fixing symbionts. This led to vast changes in productivity and grazing rates in the ecosystem. This work shows that the emergence of one species can have profound effects on ecosystem function. Such changes may become more prevalent as the ocean warms due to climate change.
Claudine Hauri, Brita Irving, Sam Dupont, Rémi Pagés, Donna D. W. Hauser, and Seth L. Danielson
Biogeosciences, 21, 1135–1159, https://doi.org/10.5194/bg-21-1135-2024, https://doi.org/10.5194/bg-21-1135-2024, 2024
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Arctic marine ecosystems are highly susceptible to impacts of climate change and ocean acidification. We present pH and pCO2 time series (2016–2020) from the Chukchi Ecosystem Observatory and analyze the drivers of the current conditions to get a better understanding of how climate change and ocean acidification could affect the ecological niches of organisms.
William Hiles, Lucy C. Miller, Craig Smeaton, and William E. N. Austin
Biogeosciences, 21, 929–948, https://doi.org/10.5194/bg-21-929-2024, https://doi.org/10.5194/bg-21-929-2024, 2024
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Saltmarsh soils may help to limit the rate of climate change by storing carbon. To understand their impacts, they must be accurately mapped. We use drone data to estimate the size of three saltmarshes in NE Scotland. We find that drone imagery, combined with tidal data, can reliably inform our understanding of saltmarsh size. When compared with previous work using vegetation communities, we find that our most reliable new estimates of stored carbon are 15–20 % smaller than previously estimated.
De'Marcus Robinson, Anh L. D. Pham, David J. Yousavich, Felix Janssen, Frank Wenzhöfer, Eleanor C. Arrington, Kelsey M. Gosselin, Marco Sandoval-Belmar, Matthew Mar, David L. Valentine, Daniele Bianchi, and Tina Treude
Biogeosciences, 21, 773–788, https://doi.org/10.5194/bg-21-773-2024, https://doi.org/10.5194/bg-21-773-2024, 2024
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The present study suggests that high release of ferrous iron from the seafloor of the oxygen-deficient Santa Barabara Basin (California) supports surface primary productivity, creating positive feedback on seafloor iron release by enhancing low-oxygen conditions in the basin.
David J. Yousavich, De'Marcus Robinson, Xuefeng Peng, Sebastian J. E. Krause, Frank Wenzhöfer, Felix Janssen, Na Liu, Jonathan Tarn, Franklin Kinnaman, David L. Valentine, and Tina Treude
Biogeosciences, 21, 789–809, https://doi.org/10.5194/bg-21-789-2024, https://doi.org/10.5194/bg-21-789-2024, 2024
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Declining oxygen (O2) concentrations in coastal oceans can threaten people’s ways of life and food supplies. Here, we investigate how mats of bacteria that proliferate on the seafloor of the Santa Barbara Basin sustain and potentially worsen these O2 depletion events through their unique chemoautotrophic metabolism. Our study shows how changes in seafloor microbiology and geochemistry brought on by declining O2 concentrations can help these mats grow as well as how that growth affects the basin.
Krysten Rutherford, Katja Fennel, Lina Garcia Suarez, and Jasmin G. John
Biogeosciences, 21, 301–314, https://doi.org/10.5194/bg-21-301-2024, https://doi.org/10.5194/bg-21-301-2024, 2024
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We downscaled two mid-century (~2075) ocean model projections to a high-resolution regional ocean model of the northwest North Atlantic (NA) shelf. In one projection, the NA shelf break current practically disappears; in the other it remains almost unchanged. This leads to a wide range of possible future shelf properties. More accurate projections of coastal circulation features would narrow the range of possible outcomes of biogeochemical projections for shelf regions.
Lennart Thomas Bach
Biogeosciences, 21, 261–277, https://doi.org/10.5194/bg-21-261-2024, https://doi.org/10.5194/bg-21-261-2024, 2024
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Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.
Tsuneo Ono, Daisuke Muraoka, Masahiro Hayashi, Makiko Yorifuji, Akihiro Dazai, Shigeyuki Omoto, Takehiro Tanaka, Tomohiro Okamura, Goh Onitsuka, Kenji Sudo, Masahiko Fujii, Ryuji Hamanoue, and Masahide Wakita
Biogeosciences, 21, 177–199, https://doi.org/10.5194/bg-21-177-2024, https://doi.org/10.5194/bg-21-177-2024, 2024
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We carried out parallel year-round observations of pH and related parameters in five stations around the Japan coast. It was found that short-term acidified situations with Omega_ar less than 1.5 occurred at four of five stations. Most of such short-term acidified events were related to the short-term low salinity event, and the extent of short-term pH drawdown at high freshwater input was positively correlated with the nutrient concentration of the main rivers that flow into the coastal area.
K. Mareike Paul, Martijn Hermans, Sami A. Jokinen, Inda Brinkmann, Helena L. Filipsson, and Tom Jilbert
Biogeosciences, 20, 5003–5028, https://doi.org/10.5194/bg-20-5003-2023, https://doi.org/10.5194/bg-20-5003-2023, 2023
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Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.
Hannah Sharpe, Michel Gosselin, Catherine Lalande, Alexandre Normandeau, Jean-Carlos Montero-Serrano, Khouloud Baccara, Daniel Bourgault, Owen Sherwood, and Audrey Limoges
Biogeosciences, 20, 4981–5001, https://doi.org/10.5194/bg-20-4981-2023, https://doi.org/10.5194/bg-20-4981-2023, 2023
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We studied the impact of submarine canyon processes within the Pointe-des-Monts system on biogenic matter export and phytoplankton assemblages. Using data from three oceanographic moorings, we show that the canyon experienced two low-amplitude sediment remobilization events in 2020–2021 that led to enhanced particle fluxes in the deep-water column layer > 2.6 km offshore. Sinking phytoplankton fluxes were lower near the canyon compared to background values from the lower St. Lawrence Estuary.
Dewi Langlet, Florian Mermillod-Blondin, Noémie Deldicq, Arthur Bauville, Gwendoline Duong, Lara Konecny, Mylène Hugoni, Lionel Denis, and Vincent M. P. Bouchet
Biogeosciences, 20, 4875–4891, https://doi.org/10.5194/bg-20-4875-2023, https://doi.org/10.5194/bg-20-4875-2023, 2023
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Benthic foraminifera are single-cell marine organisms which can move in the sediment column. They were previously reported to horizontally and vertically transport sediment particles, yet the impact of their motion on the dissolved fluxes remains unknown. Using microprofiling, we show here that foraminiferal burrow formation increases the oxygen penetration depth in the sediment, leading to a change in the structure of the prokaryotic community.
Masahiko Fujii, Ryuji Hamanoue, Lawrence Patrick Cases Bernardo, Tsuneo Ono, Akihiro Dazai, Shigeyuki Oomoto, Masahide Wakita, and Takehiro Tanaka
Biogeosciences, 20, 4527–4549, https://doi.org/10.5194/bg-20-4527-2023, https://doi.org/10.5194/bg-20-4527-2023, 2023
Short summary
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This is the first study of the current and future impacts of climate change on Pacific oyster farming in Japan. Future coastal warming and acidification may affect oyster larvae as a result of longer exposure to lower-pH waters. A prolonged spawning period may harm oyster processing by shortening the shipping period and reducing oyster quality. To minimize impacts on Pacific oyster farming, in addition to mitigation measures, local adaptation measures may be required.
Taketoshi Kodama, Atsushi Nishimoto, Ken-ichi Nakamura, Misato Nakae, Naoki Iguchi, Yosuke Igeta, and Yoichi Kogure
Biogeosciences, 20, 3667–3682, https://doi.org/10.5194/bg-20-3667-2023, https://doi.org/10.5194/bg-20-3667-2023, 2023
Short summary
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Carbon and nitrogen are essential elements for organisms; their stable isotope ratios (13C : 12C, 15N : 14N) are useful tools for understanding turnover and movement in the ocean. In the Sea of Japan, the environment is rapidly being altered by human activities. The 13C : 12C of small organic particles is increased by active carbon fixation, and phytoplankton growth increases the values. The 15N : 14N variations suggest that nitrates from many sources contribute to organic production.
Aubin Thibault de Chanvalon, George W. Luther, Emily R. Estes, Jennifer Necker, Bradley M. Tebo, Jianzhong Su, and Wei-Jun Cai
Biogeosciences, 20, 3053–3071, https://doi.org/10.5194/bg-20-3053-2023, https://doi.org/10.5194/bg-20-3053-2023, 2023
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The intensity of the oceanic trap of CO2 released by anthropogenic activities depends on the alkalinity brought by continental weathering. Between ocean and continent, coastal water and estuaries can limit or favour the alkalinity transfer. This study investigate new interactions between dissolved metals and alkalinity in the oxygen-depleted zone of estuaries.
Joonas J. Virtasalo, Peter Österholm, and Eero Asmala
Biogeosciences, 20, 2883–2901, https://doi.org/10.5194/bg-20-2883-2023, https://doi.org/10.5194/bg-20-2883-2023, 2023
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We mixed acidic metal-rich river water from acid sulfate soils and seawater in the laboratory to study the flocculation of dissolved metals and organic matter in estuaries. Al and Fe flocculated already at a salinity of 0–2 to large organic flocs (>80 µm size). Precipitation of Al and Fe hydroxide flocculi (median size 11 µm) began when pH exceeded ca. 5.5. Mn transferred weakly to Mn hydroxides and Co to the flocs. Up to 50 % of Cu was associated with the flocs, irrespective of seawater mixing.
Moritz Baumann, Allanah Joy Paul, Jan Taucher, Lennart Thomas Bach, Silvan Goldenberg, Paul Stange, Fabrizio Minutolo, and Ulf Riebesell
Biogeosciences, 20, 2595–2612, https://doi.org/10.5194/bg-20-2595-2023, https://doi.org/10.5194/bg-20-2595-2023, 2023
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The sinking velocity of marine particles affects how much atmospheric CO2 is stored inside our oceans. We measured particle sinking velocities in the Peruvian upwelling system and assessed their physical and biochemical drivers. We found that sinking velocity was mainly influenced by particle size and porosity, while ballasting minerals played only a minor role. Our findings help us to better understand the particle sinking dynamics in this highly productive marine system.
Kyle E. Hinson, Marjorie A. M. Friedrichs, Raymond G. Najjar, Maria Herrmann, Zihao Bian, Gopal Bhatt, Pierre St-Laurent, Hanqin Tian, and Gary Shenk
Biogeosciences, 20, 1937–1961, https://doi.org/10.5194/bg-20-1937-2023, https://doi.org/10.5194/bg-20-1937-2023, 2023
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Climate impacts are essential for environmental managers to consider when implementing nutrient reduction plans designed to reduce hypoxia. This work highlights relative sources of uncertainty in modeling regional climate impacts on the Chesapeake Bay watershed and consequent declines in bay oxygen levels. The results demonstrate that planned water quality improvement goals are capable of reducing hypoxia levels by half, offsetting climate-driven impacts on terrestrial runoff.
Linquan Mu, Jaime B. Palter, and Hongjie Wang
Biogeosciences, 20, 1963–1977, https://doi.org/10.5194/bg-20-1963-2023, https://doi.org/10.5194/bg-20-1963-2023, 2023
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Enhancing ocean alkalinity accelerates carbon dioxide removal from the atmosphere. We hypothetically added alkalinity to the Amazon River and examined the increment of the carbon uptake by the Amazon plume. We also investigated the minimum alkalinity addition in which this perturbation at the river mouth could be detected above the natural variability.
Cited articles
Abadie, C., Lacan, F., Radic, A., Pradoux, C., and Poitrasson, F.: Iron
isotopes reveal distinct dissolved iron sources and pathways in the
intermediate versus deep Southern Ocean, P. Natl. Acad. Sci. USA, 114, 858–863,
https://doi.org/10.1073/pnas.1603107114, 2017.
Achterberg, E. P., Steigenberger, S., Marsay, C. M., LeMoigne, F. A. C.,
Painter, S. C., Baker, A. R., Connelly, D. P., Moore, C. M., Tagliabue, A.,
and Tanhua, T.: Iron Biogeochemistry in the High Latitude North Atlantic
Ocean, Sci. Rep.-UK, 8, https://doi.org/10.1038/s41598-018-19472-1, 2018.
Baars, O. and Croot, P. L.: Dissolved cobalt speciation and reactivity in
the eastern tropical North Atlantic, Mar. Chem., 173, 310–319,
https://doi.org/10.1016/j.marchem.2014.10.006, 2015.
Baker, A. R., Adams, C., Bell, T. G., Jickells, T. D., and Ganzeveld, L.:
Estimation of atmospheric nutrient inputs to the Atlantic Ocean from
50∘ N to 50∘ S based on large-scale field sampling: Iron
and other dust-associated elements, Global Biogeochem. Cy., 27, 755–767,
https://doi.org/10.1002/gbc.20062, 2013.
Balistrieri, L., Brewer, P. G., and Murray, J. W.: Scavenging residence
times of trace metals and surface chemistry of sinking particles in the deep
ocean, Deep-Sea Res. Pt. A, 28, 101–121,
https://doi.org/10.1016/0198-0149(81)90085-6, 1981.
Barton, E. D.: The
Poleward Undercurrent On The Eastern Boundary Of The Subtropical North
Atlantic, in: Poleward Flows Along Eastern Ocean Boundaries, edited by: Neshyba, S. J.,
Mooers, C. N. K., Smith, R. L., and Barber, R. T., Springer-Verlag,
New York, https://doi.org/10.1029/CE034, 1989.
Barton, E. D., Aristegui, J., Tett, P., Canton, M., Garcia-Braun, J.,
Hernandez-Leon, S., Nykjaer, L., Almeida, C., Almunia, J., Ballesteros, S.,
Basterretxea, G., Escanez, J., Garcia-Weill, L., Hernandez-Guerra, A.,
Lopez-Laatzen, F., Molina, R., Montero, M. F., Navarro-Perez, E., Rodriguez,
J. M., van Lenning, K., Velez, H., and Wild, K.: The transition zone of the
Canary Current upwelling region, Prog. Oceanogr., 41, 455–504,
https://doi.org/10.1016/S0079-6611(98)00023-8, 1998.
Beck, A. J., Tsukamoto, Y., Tovar-Sanchez, A., Huerta-Diaz, M., Bokuniewicz,
H. J., and Sanudo-Wilhelmy, S. A.: Importance of geochemical transformations
in determining submarine groundwater discharge-derived trace metal and
nutrient fluxes, Appl. Geochem., 22, 477–490, https://doi.org/10.1016/j.apgeochem.2006.10.005, 2007.
Biller, D. V. and Bruland, K. W.: Sources and distributions of Mn, Fe, Co,
Ni, Cu, Zn, and Cd relative to macronutrients along the central California
coast during the spring and summer upwelling season, Mar. Chem., 155, 50–70,
https://doi.org/10.1016/j.marchem.2013.06.003, 2013.
Boyd, P. W.: Biogeochemistry – Iron findings, Nature, 446, 989–991,
https://doi.org/10.1038/446989a, 2007.
Boyle, E. A., Lee, J.-M., Echegoyen, Y., Noble, A., Moos, S., Carrasco, G.,
Zhao, N., Kayser, R., Zhang, J., and Gamo, T.: Anthropogenic lead emissions
in the ocean: The evolving global experiment, Oceanography, 27, 69–75,
https://doi.org/10.5670/oceanog.2014.10, 2014.
Brandt, P., Bange, H. W., Banyte, D., Dengler, M., Didwischus, S.-H., Fischer, T., Greatbatch, R. J., Hahn, J., Kanzow, T., Karstensen, J., Körtzinger, A., Krahmann, G., Schmidtko, S., Stramma, L., Tanhua, T., and Visbeck, M.: On the role of circulation and mixing in the ventilation of oxygen minimum zones with a focus on the eastern tropical North Atlantic, Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, 2015.
Bridgestock, L., van de Flierdt, T. V., Rehkamper, M., Paul, M., Middag, R.,
Milne, A., Lohan, M. C., Baker, A. R., Chance, R., Khondoker, R.,
Strekopytov, S., Humphreys-Williams, E., Achterberg, E. P., Rijkenberg, M.
J. A., Gerringa, L. J. A., and de Baar, H. J. W.: Return of naturally
sourced Pb to Atlantic surface waters, Nat. Commun., 7, 12921,
https://doi.org/10.1038/ncomms12921, 2016.
Browning, T. J., Achterberg, E. P., Rapp, I., Engel, A., Bertrand, E. M.,
Tagliabue, A., and Moore, C. M.: Nutrient co-limitation at the boundary of
an oceanic gyre, Nature, 551, 242–246, https://doi.org/10.1038/nature24063,
2017.
Bruland, K. W. and Lohan, M. C.: Controls of Trace Metals in Seawater, in:
The Oceans and Marine Geochemistry, edited by: Elderfield, H., Treatise on
Geochemistry, Vol. 6, Elsevier, Oxford, 2006.
Buck, C. S., Landing, W. M., Resing, J. A., and Measures, C. I.: The
solubility and deposition of aerosol Fe and other trace elements in the
North Atlantic Ocean: Observations from the A16N CLIVAR/CO2 repeat
hydrography section, Mar. Chem., 120, 57–70,
https://doi.org/10.1016/j.marchem.2008.08.003, 2010.
Burdige, D. J.: The biogeochemistry of manganese and iron reduction in
marine sediments, Earth-Sci. Rev., 35, 249–284,
https://doi.org/10.1016/0012-8252(93)90040-E, 1993.
Capet, X. J., Marchesiello, P., and McWilliams, J. C.: Upwelling response to
coastal wind profiles, Geophys. Res. Lett., 31, L13311,
https://doi.org/10.1029/2004GL020123, 2004.
Chaillou, G., Anschutz, P., Lavaux, G., Schafer, J., and Blanc, G.: The
distribution of Mo, U, and Cd in relation to major redox species in muddy
sediments of the Bay of Biscay, Mar. Chem., 80, 41–59,
https://doi.org/10.1016/S0304-4203(02)00097-X, 2002.
Charette, M. A., Morris, P. J., Henderson, P. B., and Moore, W. S.: Radium
isotope distributions during the US GEOTRACES North Atlantic cruises, Mar.
Chem., 177, 184–195, https://doi.org/10.1016/j.marchem.2015.01.001, 2015.
Conway, T. M. and John, S. G.: Quantification of dissolved iron sources to
the North Atlantic Ocean, Nature, 511, 212–215,
https://doi.org/10.1038/nature13482, 2014.
Croot, P. L., Streu, P., and Baker, A. R.: Short residence time for iron in
surface seawater impacted by atmospheric dry deposition from Saharan dust
events, Geophys. Res. Lett., 31, L23S08, https://doi.org/10.1029/2004GL020153,
2004.
Cyr, F., Bourgault, D., Galbraith, P. S., and Gosselin, M.: Turbulent
nitrate fluxes in the Lower St. Lawrence Estuary, Canada, J. Geophys.
Res.-Oceans, 120, 2308–2330, https://doi.org/10.1002/2014jc010272, 2015.
Dale, A. W., Sommer, S., Ryabenko, E., Noffke, A., Bohlen, L., Wallmann, K.,
Stolpovsky, K., Greinert, J., and Pfannkuche, O.: Benthic nitrogen fluxes and
fractionation of nitrate in the Mauritanian oxygen minimum zone (Eastern
Tropical North Atlantic), Geochim. Cosmochim. Ac., 134, 234–256,
https://doi.org/10.1016/j.gca.2014.02.026, 2014.
Dammshäuser, A., Wagener, T., and Croot, P. L.: Surface water dissolved
aluminum and titanium: Tracers for specific time scales of dust deposition
to the Atlantic?, Geophys. Res. Lett., 38, L24601,
https://doi.org/10.1029/2011gl049847, 2011.
Desbiolles, F., Blanke, B., and Bentamy, A.: Short-term upwelling events at
the western African coast related to synoptic atmospheric structures as
derived from satellite observations, J. Geophys. Res.-Oceans., 119, 461–483,
https://doi.org/10.1002/2013JC009278, 2014.
Desbiolles, F., Blanke, B., Bentamy, A., and Roy, C.: Response of the
Southern Benguela upwelling system to fine-scale modifications of the
coastal wind, J. Marine Syst., 156, 46–55,
https://doi.org/10.1016/j.jmarsys.2015.12.002, 2016.
Elrod, V. A., Berelson, W. M., Coale, K. H., and Johnson, K. S.: The flux of
iron from continental shelf sediments: A missing source for global budgets,
Geophys. Res. Lett., 31, L12307, https://doi.org/10.1029/2004gl020216, 2004.
Eriksen, C. C.: Observations of internal wave reflection off sloping
bottoms, J. Geophys. Res.-Oceans, 87, 525–538,
https://doi.org/10.1029/JC087iC01p00525, 1982.
Fairall, C. W., Bradley, E. F., Hare, J. E., Grachev, A. A., and Edson, J. B.:
Bulk Parameterization of Air–Sea Fluxes: Updates and Verification for the
COARE Algorithm, J. Climate, 16, 571–591,
https://doi.org/10.1175/1520-0442(2003)016<0571:BPOASF>2.0.CO;2, 2003.
Fitzsimmons, J. N., Zhang, R. F., and Boyle, E. A.: Dissolved iron in the
tropical North Atlantic Ocean, Mar. Chem., 154, 87–99,
https://doi.org/10.1016/j.marchem.2013.05.009, 2013.
Fitzsimmons, J. N., John, S. G., Marsay, C. M., Hoffman, C. L., Nicholas, S.
L., Toner, B. M., German, C. R., and Sherrell, R. M.: Iron persistence in a
distal hydrothermal plume supported by dissolved-particulate exchange, Nat.
Geosci., 10, 195–201, https://doi.org/10.1038/Ngeo2900, 2017.
Froelich, P. N., Klinkhammer, G. P., Bender, M. L., Luedtke, N. A., Heath,
G. R., Cullen, D., Dauphin, P., Hammond, D., Hartman, B., and Maynard, V.:
Early oxidation of organic matter in pelagic sediments of the Eastern
Equatorial Atlantic: suboxic diagenesis, Geochim. Cosmochim. Ac., 43,
1075–1090, https://doi.org/10.1016/0016-7037(79)90095-4, 1979.
Garcia-Solsona, E., Garcia-Orellana, J., Masqué, P., and Dulaiova, H.:
Uncertainties associated with 223Ra and 224Ra measurements in
water via a Delayed Coincidence Counter (RaDeCC), Mar. Chem., 109, 198–219,
https://doi.org/10.1016/j.marchem.2007.11.006, 2008.
Gehlen, M., Beck, L., Calas, G., Flank, A. M., Van Bennekom, A. J., and Van
Beusekom, J. E. E.: Unraveling the atomic structure of biogenic silica:
Evidence of the structural association of Al and Si in diatom frustules,
Geochim. Cosmochim. Ac., 66, 1601–1609,
https://doi.org/10.1016/S0016-7037(01)00877-8, 2002.
Gill, A.: Atmosphere-Ocean Dynamics, Academic Press, California, 1982.
Grasshoff, K., Ehrhardt, M., and Kremling, K.: Methods of Seawater Analysis,
Verlag Chemie, Weinheim, 1983.
Green, M. A., Aller, R. C., Cochran, J. K., Lee, C., and Aller, J. Y.:
Bioturbation in shelf/slope sediments off Cape Hatteras, North Carolina: the
use of 234Th, Chl-a, and Br− to evaluate rates of particle and
solute transport, Deep-Sea Res. Pt. II, 49, 4627–4644,
https://doi.org/10.1016/S0967-0645(02)00132-7, 2002.
Hahn, J., Brandt, P., Schmidtko, S., and Krahmann, G.: Decadal oxygen change in the eastern tropical North Atlantic, Ocean Sci., 13, 551–576, https://doi.org/10.5194/os-13-551-2017, 2017.
Hansen, H. P.: Determination of oxygen, Methods of Seawater Analysis, 3rd
Edn., 75–89, https://doi.org/10.1002/9783527613984.ch10, 2007.
Hartmann, M., Müller, P. J., Suess, E., and van der Weijden, C. H.:
Chemistry of Late Quaternary sediments and their interstitial waters of
sediment cores from the North-West African continental margin, in: Supplement
to: Hartmann, M., et al. (1976): Chemistry of Late Quaternary sediments and
their interstitial waters from the northwest African continental margin.
Meteor Forschungsergebnisse, Deutsche Forschungsgemeinschaft, Reihe C
Geologie und Geophysik, Gebrüder Bornträger, Berlin, Stuttgart, C24,
1–67, PANGAEA, https://doi.org/10.1594/PANGAEA.548430, 1976.
Hatta, M., Measures, C. I., Wu, J. F., Roshan, S., Fitzsimmons, J. N.,
Sedwick, P., and Morton, P.: An overview of dissolved Fe and Mn
distributions during the 2010–2011 US GEOTRACES north Atlantic cruises:
GEOTRACES GA03, Deep-Sea Res. Pt. II, 116, 117–129,
https://doi.org/10.1016/j.dsr2.2014.07.005, 2015.
Hayes, S. P., Chang, P., and McPhaden, M. J.: Variability of the sea surface
temperature in the eastern equatorial Pacific during 1986–1988, J. Geophys.
Res., 96, 10553–10566, https://doi.org/10.1029/91JC00942, 1991.
Hawco, N. J., Ohnemus, D. C., Resing, J. A., Twining, B. S., and Saito, M. A.: A dissolved cobalt plume in the oxygen minimum zone of the eastern tropical South Pacific, Biogeosciences, 13, 5697–5717, https://doi.org/10.5194/bg-13-5697-2016, 2016.
Heggie, D. T.: Copper in Surface Waters of the Bering Sea, Geochim. Cosmochim.
Ac., 46, 1301–1306, https://doi.org/10.1016/0016-7037(82)90014-X, 1982.
Helly, J. J. and Levin, L. A.: Global distribution of naturally occurring
marine hypoxia on continental margins, Deep-Sea Res. Pt. I, 51, 1159–1168,
https://doi.org/10.1016/j.dsr.2004.03.009, 2004.
Henderson, P., Morris, P., Moore, W., and Charette, M.: Methodological
advances for measuring low-level radium isotopes in seawater, J. Radioanal
Nucl. Ch., 296, 357–362, https://doi.org/10.1007/s10967-012-2047-9, 2013.
Homoky, W. B., Severmann, S., McManus, J., Berelson, W. M., Riedel, T. E.,
Statham, P. J., and Mills, R. A.: Dissolved oxygen and suspended particles
regulate the benthic flux of iron from continental margins, Mar. Chem., 134,
59–70, https://doi.org/10.1016/j.marchem.2012.03.003, 2012.
Homoky, W. B., Weber, T., Berelson, W. M., Conway, T. M., Henderson, G. M.,
van Hulten, M., Jeandel, C., Severmann, S., and Tagliabue, A.: Quantifying
trace element and isotope fluxes at the ocean-sediment boundary: a review,
Philos. T. R. Soc. A, 374, 20160246, https://doi.org/10.1098/rsta.2016.0246,
2016.
Honeyman, B. D., Balistrieri, L. S., and Murray, J. W.: Oceanic trace metal
scavenging: the importance of particle concentration, Deep Sea Res. Pt. A, 35, 227–246,
https://doi.org/10.1016/0198-0149(88)90038-6, 1988.
Hurst, M. P., Aguilar-Islas, A. M., and Bruland, K. W.: Iron in the
southeastern Bering Sea: Elevated leachable particulate Fe in shelf bottom
waters as an important source for surface waters, Cont. Shelf Res., 30,
467–480, https://doi.org/10.1016/j.csr.2010.01.001, 2010.
Hydes, D. J. and Liss, P. S.: Fluorimetric method for determination of low
concentrations of dissolved aluminum in natural waters, Analyst, 101,
922–931, https://doi.org/10.1039/an9760100922, 1976.
Jickells, T. D.: The inputs of dust derived elements to the Sargasso Sea; a
synthesis, Mar. Chem., 68, 5–14,
https://doi.org/10.1016/S0304-4203(99)00061-4, 1999.
John, S. G. and Adkins, J.: The vertical distribution of iron stable
isotopes in the North Atlantic near Bermuda, Global Biogeochem. Cy., 26,
GB2034, https://doi.org/10.1029/2011gb004043, 2012.
Johnson, K. S., Stout, P. M., Berelson, W. M., and Sakamotoarnold, C. M.:
Cobalt and copper distributions in the waters of Santa-Monica Basin,
California, Nature, 332, 527–530, https://doi.org/10.1038/332527a0, 1988.
Kagaya, S., Maeba, E., Inoue, Y., Kamichatani, W., Kajiwara, T., Yanai, H.,
Saito, M., and Tohda, K.: A solid phase extraction using a chelate resin
immobilizing carboxymethylated pentaethylenehexamine for separation and
preconcentration of trace elements in water samples, Talanta, 79, 146–152,
https://doi.org/10.1016/j.talanta.2009.03.016, 2009.
Karstensen, J., Stramma, L., and Visbeck, M.: Oxygen minimum zones in the
eastern tropical Atlantic and Pacific oceans, Prog. Oceanogr., 77, 331–350,
https://doi.org/10.1016/j.pocean.2007.05.009, 2008.
Klenz, T., Dengler, M., and Brandt, P.: Seasonal variability of the
Mauritanian Undercurrent and Hydrography at 18∘ N, J. Geophys. Res.-Oceans, 123, 8122–8137, https://doi.org/10.1029/2018JC014264, 2018.
Kock, A., Schafstall, J., Dengler, M., Brandt, P., and Bange, H. W.: Sea-to-air and diapycnal nitrous oxide fluxes in the eastern tropical North Atlantic Ocean, Biogeosciences, 9, 957–964, https://doi.org/10.5194/bg-9-957-2012, 2012.
Köllner, M., Visbeck, M., Tanhua, T., and Fischer, T.: Diapycnal
diffusivity in the core and oxycline of the tropical North Atlantic oxygen
minimum zone, J. Marine Syst., 160, 54–63,
https://doi.org/10.1016/j.jmarsys.2016.03.012, 2016.
Kounta, L., Capet, X., Jouanno, J., Kolodziejczyk, N., Sow, B., and Gaye, A. T.: A model perspective on the dynamics of the shadow zone of the eastern tropical North Atlantic – Part 1: the poleward slope currents along West Africa, Ocean Sci., 14, 971–997, https://doi.org/10.5194/os-14-971-2018, 2018.
Krahmann, G., Dengler, M., and Thomsen, S.: Physical oceanography during METEOR cruise M107, PANGAEA, https://doi.org/10.1594/PANGAEA.860480, 2016.
Labatut, M., Lacan, F., Pradoux, C., Chmeleff, J., Radic, A., Murray, J. W.,
Poitrasson, F., Johansen, A. M., and Thil, F.: Iron sources and
dissolved-particulate interactions in the seawater of the Western Equatorial
Pacific, iron isotope perspectives, Global Biogeochem. Cy., 28, 1044–1065,
https://doi.org/10.1002/2014gb004928, 2014.
Lam, P. J. and Bishop, J. K. B.: The continental margin is a key source of
iron to the HNLC North Pacific Ocean, Geophys. Res. Lett., 35, L07608,
https://doi.org/10.1029/2008gl033294, 2008.
Lam, P. J., Ohnemus, D. C., and Marcus, M. A.: The speciation of marine
particulate iron adjacent to active and passive continental margins, Geochim.
Cosmochim. Ac., 80, 108–124, https://doi.org/10.1016/j.gca.2011.11.044, 2012.
Lathuilière, C., Echevin, V., and Lévy, M.: Seasonal and
intraseasonal surface chlorophyll-a variability along the northwest African
coast, J. Geophys. Res., 113, C05007, https://doi.org/10.1029/2007JC004433,
2008.
Liu, X. W. and Millero, F. J.: The solubility of iron in seawater, Mar. Chem.,
77, 43–54, https://doi.org/10.1016/S0304-4203(01)00074-3, 2002.
Lohan, M. C. and Bruland, K. W.: Elevated Fe(II) and dissolved Fe in hypoxic
shelf waters off Oregon and Washington: An enhanced source of iron to
coastal upwelling regimes, Environ. Sci. Technol., 42, 6462–6468,
https://doi.org/10.1021/es800144j, 2008.
Luther, G. W., Swartz, C. B., and Ullman, W. J.: Direct determination of
iodide in seawater by Cathodic Stripping Square-Wave Voltammetry, Anal. Chem.,
60, 1721–1724, https://doi.org/10.1021/ac00168a017, 1988.
Machu, E., Capet, X., Estrade, P. A., Ndoye, S., Brajard, J., Baurand, F.,
Auger, P.-A., Lazar, A., and Brehmer, P.: First evidence of anoxia and
nitrogen loss in the southern Canary upwelling system, Geophys. Res. Lett., 46,
2619–2627, https://doi.org/10.1029/2018GL079622, 2019.
Mahowald, N. M., Engelstaedter, S., Luo, C., Sealy, A., Artaxo, P.,
Benitez-Nelson, C., Bonnet, S., Chen, Y., Chuang, P. Y., Cohen, D. D.,
Dulac, F., Herut, B., Johansen, A. M., Kubilay, N., Losno, R., Maenhaut, W.,
Paytan, A., Prospero, J. A., Shank, L. M., and Siefert, R. L.: Atmospheric
Iron Deposition: Global Distribution, Variability, and Human Perturbations,
Annu. Rev. Mar. Sci., 1, 245–278,
https://doi.org/10.1146/annurev.marine.010908.163727, 2009.
Martin, J. H., Gordon, R. M., Fitzwater, S., and Broenkow, W. W.: Vertex –
Phytoplankton Iron Studies in the Gulf of Alaska, Deep-Sea Res., 36, 649–680,
https://doi.org/10.1016/0198-0149(89)90144-1, 1989.
Measures, C. I. and Brown, E. T.: Estimating dust input to the Atlantic
Ocean using surface water aluminium concentrations, in: The impact of desert
dust across the Mediterranean, edited by: Guerzoni, S., Chester, R.,
Environmental Science and Technology Library, Springer, Dordrecht, 1996.
Measures, C. I. and Vink, S.: On the use of dissolved aluminum in surface
waters to estimate dust deposition to the ocean, Global Biogeochem. Cy., 14,
317–327, https://doi.org/10.1029/1999gb001188, 2000.
Menzel Barraqueta, J.-L., Schlosser, C., Planquette, H., Gourain, A., Cheize, M., Boutorh, J., Shelley, R., Contreira Pereira, L., Gledhill, M., Hopwood, M. J., Lacan, F., Lherminier, P., Sarthou, G., and Achterberg, E. P.: Aluminium in the North Atlantic Ocean and the Labrador Sea (GEOTRACES GA01 section): roles of continental inputs and biogenic particle removal, Biogeosciences, 15, 5271–5286, https://doi.org/10.5194/bg-15-5271-2018, 2018.
Menzel Barraqueta, J.-L., Klar, J. K., Gledhill, M., Schlosser, C., Shelley, R., Planquette, H. F., Wenzel, B., Sarthou, G., and Achterberg, E. P.: Atmospheric deposition fluxes over the Atlantic Ocean: a GEOTRACES case study, Biogeosciences, 16, 1525–1542, https://doi.org/10.5194/bg-16-1525-2019, 2019.
Middag, R., de Baar, H. J. W., Laan, P., and Huhn, O.: The effects of
continental margins and water mass circulation on the distribution of
dissolved aluminum and manganese in Drake Passage, J. Geophys. Res.-Oceans,
117, C01019, https://doi.org/10.1029/2011jc007434, 2012.
Milne, A., Schlosser, C., Wake, B. D., Achterberg, E. P., Chance, R., Baker,
A. R., Forryan, A., and Lohan, M. C.: Particulate phases are key in
controlling dissolved iron concentrations in the (sub)tropical North
Atlantic, Geophys. Res. Lett., 44, 2377–2387,
https://doi.org/10.1002/2016gl072314, 2017.
Mittelstaedt, E.: The upwelling area off Northwest Africa – A description of
phenomena related to coastal upwelling, Prog. Oceanogr., 12, 307–331,
https://doi.org/10.1016/0079-6611(83)90012-5, 1983.
Mittelstaedt, E.: The ocean boundary along the northwest African coast:
Circulation and oceanographic properties at the sea-surface, Prog. Oceanogr.,
26, 307–355, https://doi.org/10.1016/0079-6611(91)90011-A, 1991.
Moffett, J. W.: The Relationship between cerium and manganese oxidation in
the marine environment, Limnol. Oceanogr., 39, 1309–1318,
https://doi.org/10.4319/lo.1994.39.6.1309, 1994.
Moffett, J. W. and Ho, J.: Oxidation of cobalt and manganese in seawater via
a common microbially catalyzed pathway, Geochim. Cosmochim. Ac., 60, 3415–3424, https://doi.org/10.1016/0016-7037(96)00176-7, 1996.
Moffett, J. W. and Zika, R. G.: Reaction kinetics of hydrogen peroxide with
copper and iron in seawater, Environ. Sci. Technol., 21, 804–810,
https://doi.org/10.1021/es00162a012, 1987.
Moffett, J. W., Vedamati, J., Goepfert, T. J., Pratihary, A., Gauns, M., and
Naqvi, S. W. A.: Biogeochemistry of iron in the Arabian Sea, Limnol.
Oceanogr., 60, 1671–1688, https://doi.org/10.1002/lno.10132, 2015.
Moore, C. M., Mills, M. M., Achterberg, E. P., Geider, R. J., LaRoche, J.,
Lucas, M. I., McDonagh, E. L., Pan, X., Poulton, A. J., Rijkenberg, M. J.
A., Suggett, D. J., Ussher, S. J., and Woodward, E. M. S.: Large-scale
distribution of Atlantic nitrogen fixation controlled by iron availability,
Nat. Geosci., 2, 867–871, https://doi.org/10.1038/ngeo667, 2009.
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., Maranon, 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, W. S.: 228Ra in the South-Atlantic Bight, J. Geophys. Res.-Oceans,
92, 5177–5190, https://doi.org/10.1029/JC092iC05p05177, 1987.
Moore, W. S.: Ages of continental shelf waters determined from 223Ra
and 224Ra, J. Geophys. Res.-Oceans, 105, 22117–22122,
https://doi.org/10.1029/1999jc000289, 2000.
Moore, W. S.: Seasonal distribution and flux of radium isotopes on the
southeastern U.S. continental shelf, J. Geophys. Res., 112, C10013,
https://doi.org/10.1029/2007JC004199, 2007.
Moore, W. S. and Arnold, R.: Measurement of 223Ra and 224Ra in
coastal waters using a delayed coincidence counter, J. Geophys. Res., 101,
1321–1329, https://doi.org/10.1029/95jc03139, 1996.
Moore, W. S. and Cai, P.: Calibration of RaDeCC systems for 223Ra
measurements, Mar. Chem., 156, 130–137,
https://doi.org/10.1016/j.marchem.2013.03.002, 2013.
Moran, S. B. and Moore, R. M.: The potential source of dissolved aluminum
from resuspended sediments to the North Atlantic Deep Water, Geochim.
Cosmochim. Ac., 55, 2745–2751, https://doi.org/10.1016/0016-7037(91)90441-7,
1991.
Morel, F. M. M. and Price, N. M.: The biogeochemical cycles of trace metals
in the oceans, Science, 300, 944–947,
https://doi.org/10.1126/science.1083545, 2003.
Naykki, T., Virtanen, A., Kaukonen, L., Magnusson, B., Vaisanen, T., and
Leito, I.: Application of the Nordtest method for “real-time” uncertainty
estimation of on-line field measurement, Environ. Monit. Assess., 187, 360,
https://doi.org/10.1007/s10661-015-4856-0, 2015.
Ndoye, S., Capet, X., Estrade, P., Sow, B., Dagorne, D., Lazar, A., Gaye,
A., and Brehmer, P.: SST patterns and dynamics of the southern
Senegal-Gambia upwelling center, J. Geophys. Res.-Oceans, 119, 8315–8335,
https://doi.org/10.1002/2014JC010242, 2014.
Noble, A. E., Lamborg, C. H., Ohnemus, D. C., Lam, P. J., Goepfert, T. J.,
Measures, C. I., Frame, C. H., Casciotti, K. L., DiTullio, G. R., Jennings,
J., and Saito, M. A.: Basin-scale inputs of cobalt, iron, and manganese from
the Benguela-Angola front to the South Atlantic Ocean, Limnol. Oceanogr., 57,
989–1010, https://doi.org/10.4319/lo.2012.57.4.0989, 2012.
Noble, A. E., Echegoyen-Sanz, Y., Boyle, E. A., Ohnemus, D. C., Lam, P. J.,
Kayser, R., Reuer, M., Wu, J. F., and Smethie, W.: Dynamic variability of
dissolved Pb and Pb isotope composition from the US North Atlantic GEOTRACES
transect, Deep-Sea Res. Pt. II, 116, 208–225,
https://doi.org/10.1016/j.dsr2.2014.11.011, 2015.
Noble, A. E., Ohnemus, D. C., Hawco, N. J., Lam, P. J., and Saito, M. A.: Coastal sources, sinks and strong organic complexation of dissolved cobalt within the US North Atlantic GEOTRACES transect GA03, Biogeosciences, 14, 2715–2739, https://doi.org/10.5194/bg-14-2715-2017, 2017.
Noffke, A., Hensen, C., Sommer, S., Scholz, F., Bohlen, L., Mosch, T.,
Graco, M., and Wallmann, K.: Benthic iron and phosphorus fluxes across the
Peruvian oxygen minimum zone, Limnol. Oceanogr., 57, 851–867,
https://doi.org/10.4319/lo.2012.57.3.0851, 2012.
Nriagu, J. O. and Pacyna, J. M.: Quantitative assessment of worldwide
contamination of air, water and soils by trace metals, Nature, 333, 134–139,
https://doi.org/10.1038/333134a0, 1988.
Nychka, D., Furrer, R., Paige, J., and Sain, S.: fields: Tools for Spatial
Data, R package version 8.3-6, available at: https://CRAN.R-project.org/package=fields (last access: 4 March 2018),
2016.
Oksanen, J., Blanchet, F. G., Friendly, M., Kindt, R., Legendre, P.,
McGlinn, D., Minchin, P., B. O'Hara, R., Simpson, G., Solymos, P., Stevens,
H., Szöcs, E., and Wagner, H.: vegan: Community Ecology Package.
Ordination methods, diversity analysis and other functions for community and
vegetation ecologists, version 2.5-1, available at:
https://CRAN.R-project.org/package=vegan, last access: 5 May 2018.
Oldham, V. E., Jones, M. R., Tebo, B. M., and Luther, G. W.: Oxidative and
reductive processes contributing to manganese cycling at oxic-anoxic
interfaces, Mar. Chem., 195, 122–128,
https://doi.org/10.1016/j.marchem.2017.06.002, 2017.
Orians, K. J. and Bruland, K. W.: Dissolved aluminum in the Central North
Pacific, Nature, 316, 427–429, https://doi.org/10.1038/316427a0, 1985.
Orians, K. J. and Bruland, K. W.: The biogeochemistry of aluminum in the
Pacific Ocean, Earth Planet Sc. Lett., 78, 397–410,
https://doi.org/10.1016/0012-821x(86)90006-3, 1986.
Osborn, T. R.: Estimates of the local rate of vertical diffusion from
dissipation measurements, J. Phys. Oceanogr., 10, 83–89, https://doi.org/10.1175/1520-0485(1980)010<0083:Eotlro>2.0.Co;2, 1980.
Parker, D. L., Morita, T., Mozafarzadeh, M. L., Verity, R., McCarthy, J. K.,
and Tebo, B. M.: Inter-relationships of MnO2 precipitation,
siderophore-Mn(III) complex formation, siderophore degradation, and iron
limitation in Mn(II)-oxidizing bacterial cultures, Geochim. Cosmochim. Ac., 71,
5672–5683, https://doi.org/10.1016/j.gca.2007.03.042, 2007.
Patey, M. D., Achterberg, E. P., Rijkenberg, M. J., and Pearce, R.: Aerosol
time-series measurements over the tropical Northeast Atlantic Ocean: Dust
sources, elemental composition and mineralogy, Mar. Chem., 174, 103–119,
https://doi.org/10.1016/j.marchem.2015.06.004, 2015.
Peña-Izquierdo, J., van Sebille, E., Pelegri, J. L., Sprintall, J.,
Mason, E., Llanillo, P. J., and Machin, F.: Water mass pathways to the North
Atlantic oxygen minimum zone, J. Geophys. Res.-Oceans, 120, 3350–3372,
https://doi.org/10.1002/2014jc010557, 2015.
Rama and Moore, W. S.: Using the radium quartet for evaluating groundwater
input and water exchange in salt marshes, Geochim. Cosmochim. Ac., 60,
4645–4652, https://doi.org/10.1016/S0016-7037(96)00289-X, 1996.
Rapp, I.: Trace metal data from water samples during METEOR cruise M107, PANGAEA, https://doi.org/10.1594/PANGAEA.907160, 2019.
Rapp, I., Schlosser, C., Rusiecka, D., Gledhill, M., and Achterberg, E. P.:
Automated preconcentration of Fe, Zn, Cu, Ni, Cd, Pb, Co, and Mn in seawater
with analysis using high-resolution sector field inductively-coupled plasma
mass spectrometry, Anal Chim. Acta, 976, 1–13,
https://doi.org/10.1016/j.aca.2017.05.008, 2017.
Rhein, M., Dengler, M., Sültenfuß, J., Hummels, R., Hüttl-Kabus,
S., and Bourles, B.: Upwelling and associated heat flux in the equatorial
Atlantic inferred from helium isotope disequilibrium, J. Geophys. Res., 115,
C08021, https://doi.org/10.1029/2009JC005772, 2010.
Ricciardulli, L. and Wentz, F. J.: Remote Sensing Systems ASCAT C-2015 Daily
Ocean Vector Winds on 0.25 deg grid, Version 02.1. Santa Rosa, CA, Remote
Sensing Systems, available at: http://www.remss.com/missions/ascat (last access: 29 March 2019), 2016.
Rijkenberg, M. J. A., Steigenberger, S., Powell, C. F., van Haren, H.,
Patey, M. D., Baker, A. R., and Achterberg, E. P.: Fluxes and distribution
of dissolved iron in the eastern (sub-) tropical North Atlantic Ocean,
Global Biogeochem. Cy., 26, GB3004, https://doi.org/10.1029/2011gb004264,
2012.
Rijkenberg, M. J. A., Middag, R., Laan, P., Gerringa, L. J. A., van Aken, H.
M., Schoemann, V., de Jong, J. T. M., and de Baar, H. J. W.: The
distribution of dissolved iron in the West Atlantic Ocean, Plos One, 9,
e101323, https://doi.org/10.1371/journal.pone.0101323, 2014.
Rudnick, R. L. and Gao, S.: Composition of the continental crust, in:
Treatise on geochemistry, edited by: Holland, H. D., Turekian, K. K.,
Pergamon, Oxford, UK, 2006.
Rue, E. L., Smith, G. J., Cutter, G. A., and Bruland, K. W.: The response of
trace element redox couples to suboxic conditions in the water column,
Deep-Sea Res. Pt. I, 44, 113–134,
https://doi.org/10.1016/S0967-0637(96)00088-X, 1997.
Rusiecka, D., Gledhill, M., Milne, A., Achterberg, E. P., Annett, A. L.,
Atkinson, S., Birchill, A., Karstensen, J., Lohan, M., Mariez, C., Middag,
R., Rolison, J. M., Tanhua, T., Ussher, S., and Connelly, D.: Anthropogenic
signatures of lead in the Northeast Atlantic, Geophys. Res. Lett., 45,
2734–2743, https://doi.org/10.1002/2017gl076825, 2018.
Saito, M. A., Goepfert, T. J., and Ritt, J. T.: Some thoughts on the concept
of colimitation: Three definitions and the importance of bioavailability,
Limnol. Oceanogr., 53, 276–290, https://doi.org/10.4319/lo.2008.53.1.0276,
2008.
Saito, M. A., Noble, A. E., Hawco, N., Twining, B. S., Ohnemus, D. C., John, S. G., Lam, P., Conway, T. M., Johnson, R., Moran, D., and McIlvin, M.: The acceleration of dissolved cobalt's ecological stoichiometry due to biological uptake, remineralization, and scavenging in the Atlantic Ocean, Biogeosciences, 14, 4637–4662, https://doi.org/10.5194/bg-14-4637-2017, 2017.
Schafstall, J., Dengler, M., Brandt, P., and Bange, H.: Tidal-induced mixing
and diapycnal nutrient fluxes in the Mauritanian upwelling region, J. Geophys.
Res.-Oceans, 115, C10014, https://doi.org/10.1029/2009jc005940, 2010.
Schlosser, C., Streu, P., Frank, M., Lavik, G., Croot, P. L., Dengler, M.,
and Achterberg, E. P.: H2S events in the Peruvian oxygen minimum zone
facilitate enhanced dissolved Fe concentrations, Sci. Rep.-UK, 8, 12642,
https://doi.org/10.1038/s41598-018-30580-w, 2018.
Schmidtko, S., Stramma, L., and Visbeck, M.: Decline in global oceanic
oxygen content during the past five decades, Nature, 542, 335–339,
https://doi.org/10.1038/nature21399, 2017.
Scholten, J. C., Pham, M. K., Blinova, O., Charette, M. A., Dulaiova, H.,
and Eriksson, M.: Preparation of Mn-fiber standards for the efficiency
calibration of the delayed coincidence counting system (RaDeCC), Mar. Chem.,
121, 206–214, https://doi.org/10.1016/j.marchem.2010.04.009, 2010.
Scholz, F., Loscher, C. R., Fiskal, A., Sommer, S., Hensen, C., Lomnitz, U.,
Wuttig, K., Gottlicher, J., Kossel, E., Steininger, R., and Canfield, D. E.:
Nitrate-dependent iron oxidation limits iron transport in anoxic ocean
regions, Earth Planet. Sc. Lett., 454, 272–281,
https://doi.org/10.1016/j.epsl.2016.09.025, 2016.
Schroller-Lomnitz, U., Hensen, C., Dale, A. W., Scholz, F., Clemens, D.,
Sommer, S., Noffke, A., and Wallmann, K.: Dissolved benthic phosphate, iron
and carbon fluxes in the Mauritanian upwelling system and implications for
ongoing deoxygenation, Deep-Sea Res. Pt. I, 143, 70–84,
https://doi.org/10.1016/j.dsr.2018.11.008, 2019.
Severmann, S., McManus, J., Berelson, W. M., and Hammond, D. E.: The
continental shelf benthic iron flux and its isotope composition, Geochim.
Cosmochim. Ac., 74, 3984–4004, https://doi.org/10.1016/j.gca.2010.04.022,
2010.
Shelley, R. U., Morton, P. L., and Landing, W. M.: Elemental ratios and
enrichment factors in aerosols from the US-GEOTRACES North Atlantic
transects, Deep-Sea Res. Pt. II, 116, 262–272,
https://doi.org/10.1016/j.dsr2.2014.12.005, 2015.
Shelley, R. U., Landing, W. M., Ussher, S. J., Planquette, H., and Sarthou, G.: Regional trends in the fractional solubility of Fe and other metals from North Atlantic aerosols (GEOTRACES cruises GA01 and GA03) following a two-stage leach, Biogeosciences, 15, 2271–2288, https://doi.org/10.5194/bg-15-2271-2018, 2018.
Sherrell, R. M. and Boyle, E. A.: The trace metal composition of suspended
particles in the oceanic water column near Bermuda, Earth Planet. Sc. Lett.,
111, 155–174, https://doi.org/10.1016/0012-821x(92)90176-V, 1992.
Soataert, K., Petzoldt, T., and Meysman, F.: marelac: Tools for Aquatic
Sciences, Version 2.1.6, available at: https://CRAN.R-project.org/package=marelac (last access: 30 June 2017), 2016.
Sommer, S. and Dengler, M.: Hydrochemistry of water samples during METEOR cruise M107, PANGAEA, https://doi.org/10.1594/PANGAEA.885109, 2018.
Sommer, S., Dengler, M., and Treude, T.: Benthic element cycling, fluxes and
transport of solutes across the benthic boundary layer in the Mauritanian
oxygen minimum zone, (SFB754) – Cruise No. M107 – May 30–July 03, 2014
– Fortaleza (Brazil) – Las Palmas (Spain), METEOR-Berichte, M107,
DFG-Senatskommission für Ozeanographie,
https://doi.org/10.2312/cr_m107, 2015.
Steinfeldt, R., Sültenfuß, J., Dengler, M., Fischer, T., and Rhein, M.: Coastal upwelling off Peru and Mauritania inferred from helium isotope disequilibrium, Biogeosciences, 12, 7519–7533, https://doi.org/10.5194/bg-12-7519-2015, 2015.
Stramma, L., Brandt, P., Schafstall, J., Schott, F., Fischer, J., and
Kortzinger, A.: Oxygen minimum zone in the North Atlantic south and east of
the Cape Verde Islands, J. Geophys. Res.-Oceans, 113, C04014,
https://doi.org/10.1029/2007jc004369, 2008a.
Stramma, L., Johnson, G. C., Sprintall, J., and Mohrholz, V.: Expanding
oxygen-minimum zones in the tropical oceans, Science, 320, 655–658,
https://doi.org/10.1126/science.1153847, 2008b.
Stumm, W. and Morgan, J. J.: Aquatic Chemistry: Chemical Equilibria and
Rates in Natural Waters, John Wiley & Sons, New York, 1995.
Sunda, W. G. and Huntsman, S. A.: Effect of sunlight on redox cycles of
manganese in the Southwestern Sargasso Sea, Deep-Sea Res., 35, 1297–1317,
https://doi.org/10.1016/0198-0149(88)90084-2, 1988.
Sunda, W. G. and Huntsman, S. A.: Photoreduction of manganese oxides in
seawater, Mar. Chem., 46, 133–152,
https://doi.org/10.1016/0304-4203(94)90051-5, 1994.
Tanhua, T. and Liu, M.: Upwelling velocity and ventilation in the
Mauritanian upwelling system estimated by CFC-12 and SF6 observations, J. Marine
Syst., 151, 57–70, https://doi.org/10.1016/j.jmarsys.2015.07.002, 2015.
Tebo, B. M. and Emerson, S.: Microbial manganese(II) oxidation in the marine
environment: a quantitative study, Biogeochemistry, 2, 149–161,
https://doi.org/10.1007/Bf02180192, 1986.
Tebo, B. M., Bargar, J. R., Clement, B. G., Dick, G. J., Murray, K. J.,
Parker, D., Verity, R., and Webb, S. M.: Biogenic manganese oxides:
Properties and mechanisms of formation, Annu. Rev. Earth Pl. Sc., 32, 287–328, https://doi.org/10.1146/annurev.earth.32.101802.120213, 2004.
Thomsen, S., Karstensen, J., Kiko, R., Krahmann, G., Dengler, M., and Engel, A.: Remote and local drivers of oxygen and nitrate variability in the shallow oxygen minimum zone off Mauritania in June 2014, Biogeosciences, 16, 979–998, https://doi.org/10.5194/bg-16-979-2019, 2019.
Tomczak, M.: An analysis of mixing in the frontal zone of South and North
Atlantic Central Water off North-West Africa, Prog. Oceanogr., 10, 173–192,
https://doi.org/10.1016/0079-6611(81)90011-2, 1981.
Tweddle, J. F., Sharples, J., Palmer, M. R., Davidson, K., and McNeill, S.:
Enhanced nutrient fluxes at the shelf sea seasonal thermoclinecaused by
stratified flow over a bank, Prog. Oceanogr., 117, 37–47,
https://doi.org/10.1016/j.pocean.2013.06.018, 2013.
Twining, B. S., Rauschenberg, S., Morton, P. L., and Vogt, S.: Metal
contents of phytoplankton and labile particulate material in the North
Atlantic Ocean, Prog. Oceanogr., 137, 261–283,
https://doi.org/10.1016/j.pocean.2015.07.001, 2015.
Ussher, S. J., Achterberg, E. P., Powell, C., Baker, A. R., Jickells, T. D.,
Torres, R., and Worsfold, P. J.: Impact of atmospheric deposition on the
contrasting iron biogeochemistry of the North and South Atlantic Ocean,
Global Biogeochem. Cy., 27, 1096–1107, https://doi.org/10.1002/gbc.20056,
2013.
Verhoef, A., Portabella, M., and Stoffelen, A.: High resolution ASCAT
scatterometer winds near the coast, IEEE T Geosci. Remote Sens., 50,
2481–248, https://doi.org/10.1109/TGRS.2011.2175001, 2012.
Véron, A., Patterson, C., and Flegal, A.: Use of stable lead isotopes to
characterize the sources of anthropogenic lead in North Atlantic surface
waters, Geochim. Cosmochim. Ac., 58, 3199–3206,
https://doi.org/10.1016/0016-7037(94)90047-7, 1994.
von Langen, P. J., Johnson, K. S., Coale, K. H., and Elrod, V. A.: Oxidation
kinetics of manganese(II) in seawater at nanomolar concentrations, Geochim.
Cosmochim. Ac., 61, 4945–4954, https://doi.org/10.1016/S0016-7037(97)00355-4,
1997.
Weiss, R. F.: The solubility of nitrogen, oxygen and argon in water and
seawater, Deep Sea Res and Oceanographic Abstracts, 17, 721–735,
https://doi.org/10.1016/0011-7471(70)90037-9, 1970.
Winkler, L. W.: Bestimmung des im Wasser gelösten Sauerstoffs, Ber. Dtsch.
Chem. Ges., 21, 2843–2855, https://doi.org/10.1002/cber.188802102122, 1888.
Wu, J. F. and Luther, G. W.: Size-fractionated iron concentrations in the
water column of the western North Atlantic Ocean, Limnol. Oceanogr., 39,
1119–1129, https://doi.org/10.4319/lo.1994.39.5.1119, 1994.
Wuttig, K., Heller, M. I., and Croot, P. L.: Pathways of Superoxide
(
Wyrtki, K.: The oxygen minima in relation to ocean circulation, Deep-Sea
Res., 9, 11–23, https://doi.org/10.1016/0011-7471(62)90243-7, 1962.
Yücel, M., Beaton, A. D., Dengler, M., Mowlem, M. C., Sohl, F., and
Sommer, S.: Nitrate and Nitrite Variability at the Seafloor of an Oxygen
Minimum Zone Revealed by a Novel Microfluidic In-Situ Chemical Sensor, PLoS
ONE, 10, e0132785, https://doi.org/10.1371/journal.pone.0132785, 2015.
Zenk, W., Klein, B., and Schroder, M.: Cape-Verde Frontal Zone, Deep-Sea
Res., 38, S505–S530, https://doi.org/10.1016/S0198-0149(12)80022-7, 1991.
Short summary
The availability of iron (Fe) affects phytoplankton growth in large parts of the ocean. Shelf sediments, particularly in oxygen minimum zones, are a major source of Fe and other essential micronutrients, such as cobalt (Co) and manganese (Mn). We observed enhanced concentrations of Fe, Co, and Mn corresponding with low oxygen concentrations along the Mauritanian shelf, indicating that the projected future decrease in oxygen concentrations may result in increases in Fe, Mn, and Co concentrations.
The availability of iron (Fe) affects phytoplankton growth in large parts of the ocean. Shelf...
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