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.
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
Related authors
Maximiliano J. Vergara-Jara, Mark J. Hopwood, Thomas J. Browning, Insa Rapp, Rodrigo Torres, Brian Reid, Eric P. Achterberg, and José Luis Iriarte
Ocean Sci., 17, 561–578, https://doi.org/10.5194/os-17-561-2021, https://doi.org/10.5194/os-17-561-2021, 2021
Short summary
Short summary
Ash from the Calbuco 2015 eruption spread across northern Patagonia, the SE Pacific and the SW Atlantic. In the Pacific, a phytoplankton bloom corresponded closely to the volcanic ash plume, suggesting that ash fertilized this region of the ocean. No such fertilization was found in the Atlantic where nutrients plausibly supplied by ash were likely already in excess of phytoplankton demand. In Patagonia, the May bloom was more intense than usual, but the mechanistic link to ash was less clear.
Ruifang C. Xie, Frédéric A. C. Le Moigne, Insa Rapp, Jan Lüdke, Beat Gasser, Marcus Dengler, Volker Liebetrau, and Eric P. Achterberg
Biogeosciences, 17, 4919–4936, https://doi.org/10.5194/bg-17-4919-2020, https://doi.org/10.5194/bg-17-4919-2020, 2020
Short summary
Short summary
Thorium-234 (234Th) is widely used to study carbon fluxes from the surface ocean to depth. But few studies stress the relevance of oceanic advection and diffusion on the downward 234Th fluxes in nearshore environments. Our study in offshore Peru showed strong temporal variations in both the importance of physical processes on 234Th flux estimates and the oceanic residence time of 234Th, whereas salinity-derived seawater 238U activities accounted for up to 40 % errors in 234Th flux estimates.
Peter Brandt, Gaël Alory, Founi Mesmin Awo, Marcus Dengler, Sandrine Djakouré, Rodrigue Anicet Imbol Koungue, Julien Jouanno, Mareike Körner, Marisa Roch, and Mathieu Rouault
Ocean Sci., 19, 581–601, https://doi.org/10.5194/os-19-581-2023, https://doi.org/10.5194/os-19-581-2023, 2023
Short summary
Short summary
Tropical upwelling systems are among the most productive ecosystems globally. The tropical Atlantic upwelling undergoes a strong seasonal cycle that is forced by the wind. Local wind-driven upwelling and remote effects, particularly via the propagation of equatorial and coastal trapped waves, lead to an upward and downward movement of the nitracline. Turbulent mixing results in upward supply of nutrients. Here, we review the different physical processes responsible for biological productivity.
Kristian Spilling, Jonna Piiparinen, Eric P. Achterberg, Javier Arístegui, Lennart T. Bach, Maria T. Camarena-Gómez, Elisabeth von der Esch, Martin A. Fischer, Markel Gómez-Letona, Nauzet Hernández-Hernández, Judith Meyer, Ruth A. Schmitz, and Ulf Riebesell
Biogeosciences, 20, 1605–1619, https://doi.org/10.5194/bg-20-1605-2023, https://doi.org/10.5194/bg-20-1605-2023, 2023
Short summary
Short summary
We carried out an enclosure experiment using surface water off Peru with different additions of oxygen minimum zone water. In this paper, we report on enzyme activity and provide data on the decomposition of organic matter. We found very high activity with respect to an enzyme breaking down protein, suggesting that this is important for nutrient recycling both at present and in the future ocean.
Damian L. Arévalo-Martínez, Amir Haroon, Hermann W. Bange, Ercan Erkul, Marion Jegen, Nils Moosdorf, Jens Schneider von Deimling, Christian Berndt, Michael Ernst Böttcher, Jasper Hoffmann, Volker Liebetrau, Ulf Mallast, Gudrun Massmann, Aaron Micallef, Holly A. Michael, Hendrik Paasche, Wolfgang Rabbel, Isaac Santos, Jan Scholten, Katrin Schwalenberg, Beata Szymczycha, Ariel T. Thomas, Joonas J. Virtasalo, Hannelore Waska, and Bradley A. Weymer
Biogeosciences, 20, 647–662, https://doi.org/10.5194/bg-20-647-2023, https://doi.org/10.5194/bg-20-647-2023, 2023
Short summary
Short summary
Groundwater flows at the land–ocean transition and the extent of freshened groundwater below the seafloor are increasingly relevant in marine sciences, both because they are a highly uncertain term of biogeochemical budgets and due to the emerging interest in the latter as a resource. Here, we discuss our perspectives on future research directions to better understand land–ocean connectivity through groundwater and its potential responses to natural and human-induced environmental changes.
Mareike Körner, Peter Brandt, and Marcus Dengler
Ocean Sci., 19, 121–139, https://doi.org/10.5194/os-19-121-2023, https://doi.org/10.5194/os-19-121-2023, 2023
Short summary
Short summary
The coastal waters off Angola host a productive ecosystem. Surface waters at the coast are colder than further offshore. We find that surface heat fluxes warm the coastal region more strongly than the offshore region and cannot explain the differences. The influence of horizontal heat advection is minor on the surface temperature change. In contrast, ocean turbulence data suggest that cooling associated with vertical mixing is an important mechanism to explain the near-coastal cooling.
Shao-Min Chen, Ulf Riebesell, Kai G. Schulz, Elisabeth von der Esch, Eric P. Achterberg, and Lennart T. Bach
Biogeosciences, 19, 295–312, https://doi.org/10.5194/bg-19-295-2022, https://doi.org/10.5194/bg-19-295-2022, 2022
Short summary
Short summary
Oxygen minimum zones in the ocean are characterized by enhanced carbon dioxide (CO2) levels and are being further acidified by increasing anthropogenic atmospheric CO2. Here we report CO2 system measurements in a mesocosm study offshore Peru during a rare coastal El Niño event to investigate how CO2 dynamics may respond to ongoing ocean deoxygenation. Our observations show that nitrogen limitation, productivity, and plankton community shift play an important role in driving the CO2 dynamics.
Loes J. A. Gerringa, Martha Gledhill, Indah Ardiningsih, Niels Muntjewerf, and Luis M. Laglera
Biogeosciences, 18, 5265–5289, https://doi.org/10.5194/bg-18-5265-2021, https://doi.org/10.5194/bg-18-5265-2021, 2021
Short summary
Short summary
For 3 decades, competitive ligand exchange–adsorptive cathodic stripping voltammetry was used to estimate the Fe-binding capacity of organic matter in seawater. In this paper the performance of the competing ligands is compared through the analysis of a series of model ligands.
The main finding of this paper is that the determined speciation parameters are not independent of the application, making interpretation of Fe speciation data more complex than it was thought before.
Kai G. Schulz, Eric P. Achterberg, Javier Arístegui, Lennart T. Bach, Isabel Baños, Tim Boxhammer, Dirk Erler, Maricarmen Igarza, Verena Kalter, Andrea Ludwig, Carolin Löscher, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Elisabeth von der Esch, Bess B. Ward, and Ulf Riebesell
Biogeosciences, 18, 4305–4320, https://doi.org/10.5194/bg-18-4305-2021, https://doi.org/10.5194/bg-18-4305-2021, 2021
Short summary
Short summary
Upwelling of nutrient-rich deep waters to the surface make eastern boundary upwelling systems hot spots of marine productivity. This leads to subsurface oxygen depletion and the transformation of bioavailable nitrogen into inert N2. Here we quantify nitrogen loss processes following a simulated deep water upwelling. Denitrification was the dominant process, and budget calculations suggest that a significant portion of nitrogen that could be exported to depth is already lost in the surface ocean.
Neil J. Wyatt, Angela Milne, Eric P. Achterberg, Thomas J. Browning, Heather A. Bouman, E. Malcolm S. Woodward, and Maeve C. Lohan
Biogeosciences, 18, 4265–4280, https://doi.org/10.5194/bg-18-4265-2021, https://doi.org/10.5194/bg-18-4265-2021, 2021
Short summary
Short summary
Using data collected during two expeditions to the South Atlantic Ocean, we investigated how the interaction between external sources and biological activity influenced the availability of the trace metals zinc and cobalt. This is important as both metals play essential roles in the metabolism and growth of phytoplankton and thus influence primary productivity of the oceans. We found seasonal changes in both processes that helped explain upper-ocean trace metal cycling.
Maximiliano J. Vergara-Jara, Mark J. Hopwood, Thomas J. Browning, Insa Rapp, Rodrigo Torres, Brian Reid, Eric P. Achterberg, and José Luis Iriarte
Ocean Sci., 17, 561–578, https://doi.org/10.5194/os-17-561-2021, https://doi.org/10.5194/os-17-561-2021, 2021
Short summary
Short summary
Ash from the Calbuco 2015 eruption spread across northern Patagonia, the SE Pacific and the SW Atlantic. In the Pacific, a phytoplankton bloom corresponded closely to the volcanic ash plume, suggesting that ash fertilized this region of the ocean. No such fertilization was found in the Atlantic where nutrients plausibly supplied by ash were likely already in excess of phytoplankton demand. In Patagonia, the May bloom was more intense than usual, but the mechanistic link to ash was less clear.
Philippe Massicotte, Rainer M. W. Amon, David Antoine, Philippe Archambault, Sergio Balzano, Simon Bélanger, Ronald Benner, Dominique Boeuf, Annick Bricaud, Flavienne Bruyant, Gwenaëlle Chaillou, Malik Chami, Bruno Charrière, Jing Chen, Hervé Claustre, Pierre Coupel, Nicole Delsaut, David Doxaran, Jens Ehn, Cédric Fichot, Marie-Hélène Forget, Pingqing Fu, Jonathan Gagnon, Nicole Garcia, Beat Gasser, Jean-François Ghiglione, Gaby Gorsky, Michel Gosselin, Priscillia Gourvil, Yves Gratton, Pascal Guillot, Hermann J. Heipieper, Serge Heussner, Stanford B. Hooker, Yannick Huot, Christian Jeanthon, Wade Jeffrey, Fabien Joux, Kimitaka Kawamura, Bruno Lansard, Edouard Leymarie, Heike Link, Connie Lovejoy, Claudie Marec, Dominique Marie, Johannie Martin, Jacobo Martín, Guillaume Massé, Atsushi Matsuoka, Vanessa McKague, Alexandre Mignot, William L. Miller, Juan-Carlos Miquel, Alfonso Mucci, Kaori Ono, Eva Ortega-Retuerta, Christos Panagiotopoulos, Tim Papakyriakou, Marc Picheral, Louis Prieur, Patrick Raimbault, Joséphine Ras, Rick A. Reynolds, André Rochon, Jean-François Rontani, Catherine Schmechtig, Sabine Schmidt, Richard Sempéré, Yuan Shen, Guisheng Song, Dariusz Stramski, Eri Tachibana, Alexandre Thirouard, Imma Tolosa, Jean-Éric Tremblay, Mickael Vaïtilingom, Daniel Vaulot, Frédéric Vaultier, John K. Volkman, Huixiang Xie, Guangming Zheng, and Marcel Babin
Earth Syst. Sci. Data, 13, 1561–1592, https://doi.org/10.5194/essd-13-1561-2021, https://doi.org/10.5194/essd-13-1561-2021, 2021
Short summary
Short summary
The MALINA oceanographic expedition was conducted in the Mackenzie River and the Beaufort Sea systems. The sampling was performed across seven shelf–basin transects to capture the meridional gradient between the estuary and the open ocean. The main goal of this research program was to better understand how processes such as primary production are influencing the fate of organic matter originating from the surrounding terrestrial landscape during its transition toward the Arctic Ocean.
Gerd Krahmann, Damian L. Arévalo-Martínez, Andrew W. Dale, Marcus Dengler, Anja Engel, Nicolaas Glock, Patricia Grasse, Johannes Hahn, Helena Hauss, Mark Hopwood, Rainer Kiko, Alexandra Loginova, Carolin R. Löscher, Marie Maßmig, Alexandra-Sophie Roy, Renato Salvatteci, Stefan Sommer, Toste Tanhua, and Hela Mehrtens
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2020-308, https://doi.org/10.5194/essd-2020-308, 2021
Preprint withdrawn
Short summary
Short summary
The project "Climate-Biogeochemistry Interactions in the Tropical Ocean" (SFB 754) was a multidisciplinary research project active from 2008 to 2019 aimed at a better understanding of the coupling between the tropical climate and ocean circulation and the ocean's oxygen and nutrient balance. On 34 research cruises, mainly in the Southeast Tropical Pacific and the Northeast Tropical Atlantic, 1071 physical, chemical and biological data sets were collected.
Yu-Te Hsieh, Walter Geibert, E. Malcolm S. Woodward, Neil J. Wyatt, Maeve C. Lohan, Eric P. Achterberg, and Gideon M. Henderson
Biogeosciences, 18, 1645–1671, https://doi.org/10.5194/bg-18-1645-2021, https://doi.org/10.5194/bg-18-1645-2021, 2021
Short summary
Short summary
The South Atlantic near 40° S is one of the high-productivity and most dynamic nutrient regions in the oceans, but the sources and fluxes of trace elements (TEs) to this region remain unclear. This study investigates seawater Ra-228 and provides important constraints on ocean mixing and dissolved TE fluxes to this region. Vertical mixing is a more important source than aeolian or shelf inputs in this region, but particulate or winter deep-mixing inputs may be required to balance the TE budgets.
Jan Lüdke, Marcus Dengler, Stefan Sommer, David Clemens, Sören Thomsen, Gerd Krahmann, Andrew W. Dale, Eric P. Achterberg, and Martin Visbeck
Ocean Sci., 16, 1347–1366, https://doi.org/10.5194/os-16-1347-2020, https://doi.org/10.5194/os-16-1347-2020, 2020
Short summary
Short summary
We analyse the intraseasonal variability of the alongshore circulation off Peru in early 2017, this circulation is very important for the supply of nutrients to the upwelling regime. The causes of this variability and its impact on the biogeochemistry are investigated. The poleward flow is strengthened during the observed time period, likely by a downwelling coastal trapped wave. The stronger current causes an increase in nitrate and reduces the deficit of fixed nitrogen relative to phosphorus.
Ruifang C. Xie, Frédéric A. C. Le Moigne, Insa Rapp, Jan Lüdke, Beat Gasser, Marcus Dengler, Volker Liebetrau, and Eric P. Achterberg
Biogeosciences, 17, 4919–4936, https://doi.org/10.5194/bg-17-4919-2020, https://doi.org/10.5194/bg-17-4919-2020, 2020
Short summary
Short summary
Thorium-234 (234Th) is widely used to study carbon fluxes from the surface ocean to depth. But few studies stress the relevance of oceanic advection and diffusion on the downward 234Th fluxes in nearshore environments. Our study in offshore Peru showed strong temporal variations in both the importance of physical processes on 234Th flux estimates and the oceanic residence time of 234Th, whereas salinity-derived seawater 238U activities accounted for up to 40 % errors in 234Th flux estimates.
Lennart Thomas Bach, Allanah Joy Paul, Tim Boxhammer, Elisabeth von der Esch, Michelle Graco, Kai Georg Schulz, Eric Achterberg, Paulina Aguayo, Javier Arístegui, Patrizia Ayón, Isabel Baños, Avy Bernales, Anne Sophie Boegeholz, Francisco Chavez, Gabriela Chavez, Shao-Min Chen, Kristin Doering, Alba Filella, Martin Fischer, Patricia Grasse, Mathias Haunost, Jan Hennke, Nauzet Hernández-Hernández, Mark Hopwood, Maricarmen Igarza, Verena Kalter, Leila Kittu, Peter Kohnert, Jesus Ledesma, Christian Lieberum, Silke Lischka, Carolin Löscher, Andrea Ludwig, Ursula Mendoza, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Joaquin Ortiz Cortes, Jonna Piiparinen, Claudia Sforna, Kristian Spilling, Sonia Sanchez, Carsten Spisla, Michael Sswat, Mabel Zavala Moreira, and Ulf Riebesell
Biogeosciences, 17, 4831–4852, https://doi.org/10.5194/bg-17-4831-2020, https://doi.org/10.5194/bg-17-4831-2020, 2020
Short summary
Short summary
The eastern boundary upwelling system off Peru is among Earth's most productive ocean ecosystems, but the factors that control its functioning are poorly constrained. Here we used mesocosms, moored ~ 6 km offshore Peru, to investigate how processes in plankton communities drive key biogeochemical processes. We show that nutrient and light co-limitation keep productivity and export at a remarkably constant level while stoichiometry changes strongly with shifts in plankton community structure.
Anna Plass, Christian Schlosser, Stefan Sommer, Andrew W. Dale, Eric P. Achterberg, and Florian Scholz
Biogeosciences, 17, 3685–3704, https://doi.org/10.5194/bg-17-3685-2020, https://doi.org/10.5194/bg-17-3685-2020, 2020
Short summary
Short summary
We compare the cycling of Fe and Cd in sulfidic sediments of the Peruvian oxygen minimum zone. Due to the contrasting solubility of their sulfide minerals, the sedimentary Fe release and Cd burial fluxes covary with spatial and temporal distributions of H2S. Depending on the solubility of their sulfide minerals, sedimentary trace metal fluxes will respond differently to ocean deoxygenation/expansion of H2S concentrations, which may change trace metal stoichiometry of upwelling water masses.
Katharina Seelmann, Martha Gledhill, Steffen Aßmann, and Arne Körtzinger
Ocean Sci., 16, 535–544, https://doi.org/10.5194/os-16-535-2020, https://doi.org/10.5194/os-16-535-2020, 2020
Short summary
Short summary
We investigated the impact of indicator dye impurities on spectrophotometric seawater measurements, especially how they may influence the drift behavior and the measurement quality of an autonomous analyzer using this indicator. These measurements are important for ocean carbon observations. This work revealed that impurities up to a quantity of 2 % do not influence the measurement drift and quality. Higher impurity levels lead to a changing drift behavior and quality deteriorations.
Mark J. Hopwood, Dustin Carroll, Thorben Dunse, Andy Hodson, Johnna M. Holding, José L. Iriarte, Sofia Ribeiro, Eric P. Achterberg, Carolina Cantoni, Daniel F. Carlson, Melissa Chierici, Jennifer S. Clarke, Stefano Cozzi, Agneta Fransson, Thomas Juul-Pedersen, Mie H. S. Winding, and Lorenz Meire
The Cryosphere, 14, 1347–1383, https://doi.org/10.5194/tc-14-1347-2020, https://doi.org/10.5194/tc-14-1347-2020, 2020
Short summary
Short summary
Here we compare and contrast results from five well-studied Arctic field sites in order to understand how glaciers affect marine biogeochemistry and marine primary production. The key questions are listed as follows. Where and when does glacial freshwater discharge promote or reduce marine primary production? How does spatio-temporal variability in glacial discharge affect marine primary production? And how far-reaching are the effects of glacial discharge on marine biogeochemistry?
Claudia Frey, Hermann W. Bange, Eric P. Achterberg, Amal Jayakumar, Carolin R. Löscher, Damian L. Arévalo-Martínez, Elizabeth León-Palmero, Mingshuang Sun, Xin Sun, Ruifang C. Xie, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 17, 2263–2287, https://doi.org/10.5194/bg-17-2263-2020, https://doi.org/10.5194/bg-17-2263-2020, 2020
Short summary
Short summary
The production of N2O via nitrification and denitrification associated with low-O2 waters is a major source of oceanic N2O. We investigated the regulation and dynamics of these processes with respect to O2 and organic matter inputs. The transcription of the key nitrification gene amoA rapidly responded to changes in O2 and strongly correlated with N2O production rates. N2O production by denitrification was clearly stimulated by organic carbon, implying that its supply controls N2O production.
Mark J. Hopwood, Nicolas Sanchez, Despo Polyviou, Øystein Leiknes, Julián Alberto Gallego-Urrea, Eric P. Achterberg, Murat V. Ardelan, Javier Aristegui, Lennart Bach, Sengul Besiktepe, Yohann Heriot, Ioanna Kalantzi, Tuba Terbıyık Kurt, Ioulia Santi, Tatiana M. Tsagaraki, and David Turner
Biogeosciences, 17, 1309–1326, https://doi.org/10.5194/bg-17-1309-2020, https://doi.org/10.5194/bg-17-1309-2020, 2020
Short summary
Short summary
Hydrogen peroxide, H2O2, is formed naturally in sunlight-exposed water by photochemistry. At high concentrations it is undesirable to biological cells because it is a stressor. Here, across a range of incubation experiments in diverse marine environments (Gran Canaria, the Mediterranean, Patagonia and Svalbard), we determine that two factors consistently affect the H2O2 concentrations irrespective of geographical location: bacteria abundance and experiment design.
Mark J. Hopwood, Carolina Santana-González, Julian Gallego-Urrea, Nicolas Sanchez, Eric P. Achterberg, Murat V. Ardelan, Martha Gledhill, Melchor González-Dávila, Linn Hoffmann, Øystein Leiknes, Juana Magdalena Santana-Casiano, Tatiana M. Tsagaraki, and David Turner
Biogeosciences, 17, 1327–1342, https://doi.org/10.5194/bg-17-1327-2020, https://doi.org/10.5194/bg-17-1327-2020, 2020
Short summary
Short summary
Fe is an essential micronutrient. Fe(III)-organic species are thought to account for > 99 % of dissolved Fe in seawater. Here we quantified Fe(II) during experiments in Svalbard, Gran Canaria, and Patagonia. Fe(II) was always a measurable fraction of dissolved Fe up to 65 %. Furthermore, when Fe(II) was allowed to decay in the dark, it remained present longer than predicted by kinetic equations, suggesting that Fe(II) is a more important fraction of dissolved Fe in seawater than widely recognized.
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
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
High metabolism and periodic hypoxia associated with drifting macrophyte detritus in the shallow subtidal Baltic Sea
Single-celled bioturbators: benthic foraminifera mediate oxygen penetration and prokaryotic diversity in intertidal sediment
Production and accumulation of reef framework by calcifying corals and macroalgae on a remote Indian Ocean cay
Zooplankton community succession and trophic links during a mesocosm experiment in the coastal upwelling off Callao Bay (Peru)
Temporal and spatial evolution of bottom-water hypoxia in the St Lawrence estuarine system
Significant nutrient consumption in the dark subsurface layer during a diatom bloom: a case study on Funka Bay, Hokkaido, Japan
Contrasts in dissolved, particulate, and sedimentary organic carbon from the Kolyma River to the East Siberian Shelf
Sediment quality assessment in an industrialized Greek coastal marine area (western Saronikos Gulf)
Limits and CO2 equilibration of near-coast alkalinity enhancement
Role of phosphorus in the seasonal deoxygenation of the East China Sea shelf
Interannual variability of the initiation of the phytoplankton growing period in two French coastal ecosystems
Observed and projected 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
Spatio-temporal distribution, photoreactivity and environmental control of dissolved organic matter in the sea-surface microlayer of the eastern marginal seas of China
Metabolic alkalinity release from large port facilities (Hamburg, Germany) and impact on coastal carbon storage
A Numerical reassessment of the Gulf of Mexico carbon system in connection with the Mississippi River and global ocean
Observed and projected global warming pressure on coastal hypoxia
Benthic alkalinity fluxes from coastal sediments of the Baltic and North seas: comparing approaches and identifying knowledge gaps
Investigating the effect of nickel concentration on phytoplankton growth to assess potential side-effects of ocean alkalinity enhancement
Unprecedented summer hypoxia in southern Cape Cod Bay: an ecological response to regional climate change?
Interannual variabilities, long-term trends, and regulating factors of low-oxygen conditions in the coastal waters off Hong Kong
Causes of the extensive hypoxia in the Gulf of Riga in 2018
Trawling effects on biogeochemical processes are mediated by fauna in high-energy biogenic-reef-inhabited coastal sediments
Drought recorded by Ba∕Ca in coastal benthic foraminifera
A nitrate budget of the Bohai Sea based on an isotope mass balance model
Suspended particulate matter drives the spatial segregation of nitrogen turnover along the hyper-turbid Ems estuary
Marine CO2 system variability along the northeast Pacific Inside Passage determined from an Alaskan ferry
Reviews and syntheses: Spatial and temporal patterns in seagrass metabolic fluxes
Mixed layer depth dominates over upwelling in regulating the seasonality of ecosystem functioning in the Peruvian upwelling system
Temporal dynamics of surface ocean carbonate chemistry in response to natural and simulated upwelling events during the 2017 coastal El Niño near Callao, Peru
Pelagic primary production in the coastal Mediterranean Sea: variability, trends, and contribution to basin-scale budgets
Contrasting patterns of carbon cycling and dissolved organic matter processing in two phytoplankton–bacteria communities
Biophysical controls on seasonal changes in the structure, growth, and grazing of the size-fractionated phytoplankton community in the northern South China Sea
Seasonal dispersal of fjord meltwaters as an important source of iron and manganese to coastal Antarctic phytoplankton
Modeling cyanobacteria life cycle dynamics and historical nitrogen fixation in the Baltic Proper
Simultaneous assessment of oxygen- and nitrate-based net community production in a temperate shelf sea from a single ocean glider
Reviews and syntheses: Physical and biogeochemical processes associated with upwelling in the Indian Ocean
Particulate organic carbon dynamics in the Gulf of Lion shelf (NW Mediterranean) using a coupled hydrodynamic–biogeochemical model
Technical note: Novel triple O2 sensor aquatic eddy covariance instrument with improved time shift correction reveals central role of microphytobenthos for carbon cycling in coral reef sands
Long-term spatiotemporal variations in and expansion of low-oxygen conditions in the Pearl River estuary: a study synthesizing observations during 1976–2017
Fe-binding organic ligands in coastal and frontal regions of the western Antarctic Peninsula
Temporal variability and driving factors of the carbonate system in the Aransas Ship Channel, TX, USA: a time series study
Nitrogen loss processes in response to upwelling in a Peruvian coastal setting dominated by denitrification – a mesocosm approach
Retracing hypoxia in Eckernförde Bight (Baltic Sea)
The impact of the freeze–melt cycle of land-fast ice on the distribution of dissolved organic matter in the Laptev and East Siberian seas (Siberian Arctic)
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
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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
Short summary
Short summary
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.
Karl M. Attard, Anna Lyssenko, and Iván F. Rodil
Biogeosciences, 20, 1713–1724, https://doi.org/10.5194/bg-20-1713-2023, https://doi.org/10.5194/bg-20-1713-2023, 2023
Short summary
Short summary
Aquatic plants produce a large amount of organic matter through photosynthesis that, following erosion, is deposited on the seafloor. In this study, we show that plant detritus can trigger low-oxygen conditions (hypoxia) in shallow coastal waters, making conditions challenging for most marine animals. We propose that the occurrence of hypoxia may be underestimated because measurements typically do not consider the region closest to the seafloor, where detritus accumulates.
Dewi Langlet, Florian Mermillod-Blondin, Noémie Deldicq, Arthur Bauville, Gwendoline Duong, Lara Konecny, Mylène Hugoni, Lionel Denis, and Vincent M. P. Bouchet
EGUsphere, https://doi.org/10.5194/egusphere-2023-705, https://doi.org/10.5194/egusphere-2023-705, 2023
Short summary
Short summary
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 here show that foraminiferal burrow formation increase the oxygen penetration depth in the sediment. Leading to a change in the structure of the prokaryotic community.
M. James McLaughlin, Cindy Bessey, Gary A. Kendrick, John Keesing, and Ylva S. Olsen
Biogeosciences, 20, 1011–1026, https://doi.org/10.5194/bg-20-1011-2023, https://doi.org/10.5194/bg-20-1011-2023, 2023
Short summary
Short summary
Coral reefs face increasing pressures from environmental change at present. The coral reef framework is produced by corals and calcifying algae. The Kimberley region of Western Australia has escaped land-based anthropogenic impacts. Specimens of the dominant coral and algae were collected from Browse Island's reef platform and incubated in mesocosms to measure calcification and production patterns of oxygen. This study provides important data on reef building and climate-driven effects.
Patricia Ayón Dejo, Elda Luz Pinedo Arteaga, Anna Schukat, Jan Taucher, Rainer Kiko, Helena Hauss, Sabrina Dorschner, Wilhelm Hagen, Mariona Segura-Noguera, and Silke Lischka
Biogeosciences, 20, 945–969, https://doi.org/10.5194/bg-20-945-2023, https://doi.org/10.5194/bg-20-945-2023, 2023
Short summary
Short summary
Ocean upwelling regions are highly productive. With ocean warming, severe changes in upwelling frequency and/or intensity and expansion of accompanying oxygen minimum zones are projected. In a field experiment off Peru, we investigated how different upwelling intensities affect the pelagic food web and found failed reproduction of dominant zooplankton. The changes projected could severely impact the reproductive success of zooplankton communities and the pelagic food web in upwelling regions.
Mathilde Jutras, Alfonso Mucci, Gwenaëlle Chaillou, William A. Nesbitt, and Douglas W. R. Wallace
Biogeosciences, 20, 839–849, https://doi.org/10.5194/bg-20-839-2023, https://doi.org/10.5194/bg-20-839-2023, 2023
Short summary
Short summary
The deep waters of the lower St Lawrence Estuary and gulf have, in the last decades, experienced a strong decline in their oxygen concentration. Below 65 µmol L-1, the waters are said to be hypoxic, with dire consequences for marine life. We show that the extent of the hypoxic zone shows a seven-fold increase in the last 20 years, reaching 9400 km2 in 2021. After a stable period at ~ 65 µmol L⁻¹ from 1984 to 2019, the oxygen level also suddenly decreased to ~ 35 µmol L-1 in 2020.
Sachi Umezawa, Manami Tozawa, Yuichi Nosaka, Daiki Nomura, Hiroji Onishi, Hiroto Abe, Tetsuya Takatsu, and Atsushi Ooki
Biogeosciences, 20, 421–438, https://doi.org/10.5194/bg-20-421-2023, https://doi.org/10.5194/bg-20-421-2023, 2023
Short summary
Short summary
We conducted repetitive observations in Funka Bay, Japan, during the spring bloom 2019. We found nutrient concentration decreases in the dark subsurface layer during the bloom. Incubation experiments confirmed that diatoms could consume nutrients at a substantial rate, even in darkness. We concluded that the nutrient reduction was mainly caused by nutrient consumption by diatoms in the dark.
Dirk Jong, Lisa Bröder, Tommaso Tesi, Kirsi H. Keskitalo, Nikita Zimov, Anna Davydova, Philip Pika, Negar Haghipour, Timothy I. Eglinton, and Jorien E. Vonk
Biogeosciences, 20, 271–294, https://doi.org/10.5194/bg-20-271-2023, https://doi.org/10.5194/bg-20-271-2023, 2023
Short summary
Short summary
With this study, we want to highlight the importance of studying both land and ocean together, and water and sediment together, as these systems function as a continuum, and determine how organic carbon derived from permafrost is broken down and its effect on global warming. Although on the one hand it appears that organic carbon is removed from sediments along the pathway of transport from river to ocean, it also appears to remain relatively ‘fresh’, despite this removal and its very old age.
Georgia Filippi, Manos Dassenakis, Vasiliki Paraskevopoulou, and Konstantinos Lazogiannis
Biogeosciences, 20, 163–189, https://doi.org/10.5194/bg-20-163-2023, https://doi.org/10.5194/bg-20-163-2023, 2023
Short summary
Short summary
The pollution of the western Saronikos Gulf from heavy metals has been examined through the study of marine sediment cores. It is a deep gulf (maximum depth 440 m) near Athens affected by industrial and volcanic activity. Eight cores were received from various stations and depths and analysed for their heavy metal content and geochemical characteristics. The results were evaluated by using statistical methods, environmental indicators and comparisons with old data.
Jing He and Michael D. Tyka
Biogeosciences, 20, 27–43, https://doi.org/10.5194/bg-20-27-2023, https://doi.org/10.5194/bg-20-27-2023, 2023
Short summary
Short summary
Recently, ocean alkalinity enhancement (OAE) has gained interest as a scalable way to address the urgent need for negative CO2 emissions. In this paper we examine the capacity of different coastlines to tolerate alkalinity enhancement and the time scale of CO2 uptake following the addition of a given quantity of alkalinity. The results suggest that OAE has significant potential and identify specific favorable and unfavorable coastlines for its deployment.
Arnaud Laurent, Haiyan Zhang, and Katja Fennel
Biogeosciences, 19, 5893–5910, https://doi.org/10.5194/bg-19-5893-2022, https://doi.org/10.5194/bg-19-5893-2022, 2022
Short summary
Short summary
The Changjiang is the main terrestrial source of nutrients to the East China Sea (ECS). Nutrient delivery to the ECS has been increasing since the 1960s, resulting in low oxygen (hypoxia) during phytoplankton decomposition in summer. River phosphorus (P) has increased less than nitrogen, and therefore, despite the large nutrient delivery, phytoplankton growth can be limited by the lack of P. Here, we investigate this link between P limitation, phytoplankton production/decomposition, and hypoxia.
Coline Poppeschi, Guillaume Charria, Anne Daniel, Romaric Verney, Peggy Rimmelin-Maury, Michaël Retho, Eric Goberville, Emilie Grossteffan, and Martin Plus
Biogeosciences, 19, 5667–5687, https://doi.org/10.5194/bg-19-5667-2022, https://doi.org/10.5194/bg-19-5667-2022, 2022
Short summary
Short summary
This paper aims to understand interannual changes in the initiation of the phytoplankton growing period (IPGP) in the current context of global climate changes over the last 20 years. An important variability in the timing of the IPGP is observed with a trend towards a later IPGP during this last decade. The role and the impact of extreme events (cold spells, floods, and wind burst) on the IPGP is also detailed.
Masahiko Fujii, Ryuji Hamanoue, Lawrence Patrick Cases Bernardo, Tsuneo Ono, Akihiro Dazai, Shigeyuki Oomoto, Masahide Wakita, and Takehiro Tanaka
Biogeosciences Discuss., https://doi.org/10.5194/bg-2022-223, https://doi.org/10.5194/bg-2022-223, 2022
Revised manuscript accepted for BG
Short summary
Short summary
This is the first study of the current and future impacts of climate change on Pacific oyster farming in Japan. Future coastal warming and acidification may affect oyster larvae, as a result of longer exposure to lower pH waters. A prolonged spawning period may harm oyster processing by shortening the shipping period and reducing oyster quality. To minimize impacts on Pacific oyster farming, in addition to mitigation measures, local adaptation measures may be required.
Lin Yang, Jing Zhang, Anja Engel, and Gui-Peng Yang
Biogeosciences, 19, 5251–5268, https://doi.org/10.5194/bg-19-5251-2022, https://doi.org/10.5194/bg-19-5251-2022, 2022
Short summary
Short summary
Enrichment factors of dissolved organic matter (DOM) in the eastern marginal seas of China exhibited a significant spatio-temporal variation. Photochemical and enrichment processes co-regulated DOM enrichment in the sea-surface microlayer (SML). Autochthonous DOM was more frequently enriched in the SML than terrestrial DOM. DOM in the sub-surface water exhibited higher aromaticity than that in the SML.
Mona Norbisrath, Johannes Pätsch, Kirstin Dähnke, Tina Sanders, Gesa Schulz, Justus E. E. van Beusekom, and Helmuth Thomas
Biogeosciences, 19, 5151–5165, https://doi.org/10.5194/bg-19-5151-2022, https://doi.org/10.5194/bg-19-5151-2022, 2022
Short summary
Short summary
Total alkalinity (TA) regulates the oceanic storage capacity of atmospheric CO2. TA is also metabolically generated in estuaries and influences coastal carbon storage through its inflows. We used water samples and identified the Hamburg port area as the one with highest TA generation. Of the overall riverine TA load, 14 % is generated within the estuary. Using a biogeochemical model, we estimated potential effects on the coastal carbon storage under possible anthropogenic and climate changes.
Le Zhang and Z. George Xue
Biogeosciences, 19, 4589–4618, https://doi.org/10.5194/bg-19-4589-2022, https://doi.org/10.5194/bg-19-4589-2022, 2022
Short summary
Short summary
We adopt a high-resolution carbon model for the Gulf of Mexico (GoM) and calculate the decadal trends of important carbon system variables in the GoM from 2001 to 2019. The GoM surface CO2 values experienced a steady increase over the past 2 decades, and the ocean surface pH is declining. Although carbonate saturation rates remain supersaturated with aragonite, they show a slightly decreasing trend. The northern GoM is a stronger carbon sink than we thought.
Michael M. Whitney
Biogeosciences, 19, 4479–4497, https://doi.org/10.5194/bg-19-4479-2022, https://doi.org/10.5194/bg-19-4479-2022, 2022
Short summary
Short summary
Coastal hypoxia is a major environmental problem of increasing severity. The 21st-century projections analyzed indicate global coastal waters will warm and experience rapid declines in oxygen. The forecasted median coastal trends for increasing sea surface temperature and decreasing oxygen capacity are 48 % and 18 % faster than the rates observed over the last 4 decades. Existing hypoxic areas are expected to worsen, and new hypoxic areas likely will emerge under these warming-related pressures.
Bryce Van Dam, Nele Lehmann, Mary A. Zeller, Andreas Neumann, Daniel Pröfrock, Marko Lipka, Helmuth Thomas, and Michael Ernst Böttcher
Biogeosciences, 19, 3775–3789, https://doi.org/10.5194/bg-19-3775-2022, https://doi.org/10.5194/bg-19-3775-2022, 2022
Short summary
Short summary
We quantified sediment–water exchange at shallow sites in the North and Baltic seas. We found that porewater irrigation rates in the former were approximately twice as high as previously estimated, likely driven by relatively high bioirrigative activity. In contrast, we found small net fluxes of alkalinity, ranging from −35 µmol m−2 h−1 (uptake) to 53 µmol m−2 h−1 (release). We attribute this to low net denitrification, carbonate mineral (re-)precipitation, and sulfide (re-)oxidation.
Jiaying Abby Guo, Robert Strzepek, Anusuya Willis, Aaron Ferderer, and Lennart Thomas Bach
Biogeosciences, 19, 3683–3697, https://doi.org/10.5194/bg-19-3683-2022, https://doi.org/10.5194/bg-19-3683-2022, 2022
Short summary
Short summary
Ocean alkalinity enhancement is a CO2 removal method with significant potential, but it can lead to a perturbation of the ocean with trace metals such as nickel. This study tested the effect of increasing nickel concentrations on phytoplankton growth and photosynthesis. We found that the response to nickel varied across the 11 phytoplankton species tested here, but the majority were rather insensitive. We note, however, that responses may be different under other experimental conditions.
Malcolm E. Scully, W. Rockwell Geyer, David Borkman, Tracy L. Pugh, Amy Costa, and Owen C. Nichols
Biogeosciences, 19, 3523–3536, https://doi.org/10.5194/bg-19-3523-2022, https://doi.org/10.5194/bg-19-3523-2022, 2022
Short summary
Short summary
For two consecutive summers, the bottom waters in southern Cape Cod Bay became severely depleted of dissolved oxygen. Low oxygen levels in bottom waters have never been reported in this area before, and this unprecedented occurrence is likely the result of a new algae species that recently began blooming during the late-summer months. We present data suggesting that blooms of this new species are the result of regional climate change including warmer waters and changes in summer winds.
Zheng Chen, Bin Wang, Chuang Xu, Zhongren Zhang, Shiyu Li, and Jiatang Hu
Biogeosciences, 19, 3469–3490, https://doi.org/10.5194/bg-19-3469-2022, https://doi.org/10.5194/bg-19-3469-2022, 2022
Short summary
Short summary
Deterioration of low-oxygen conditions in the coastal waters off Hong Kong was revealed by monitoring data over two decades. The declining wind forcing and the increasing nutrient input contributed significantly to the areal expansion and intense deterioration of low-oxygen conditions. Also, the exacerbated eutrophication drove a shift in the dominant source of organic matter from terrestrial inputs to in situ primary production, which has probably led to an earlier onset of hypoxia in summer.
Stella-Theresa Stoicescu, Jaan Laanemets, Taavi Liblik, Māris Skudra, Oliver Samlas, Inga Lips, and Urmas Lips
Biogeosciences, 19, 2903–2920, https://doi.org/10.5194/bg-19-2903-2022, https://doi.org/10.5194/bg-19-2903-2022, 2022
Short summary
Short summary
Coastal basins with high input of nutrients often suffer from oxygen deficiency. In summer 2018, the extent of oxygen depletion was exceptional in the Gulf of Riga. We analyzed observational data and found that extensive oxygen deficiency appeared since the water layer close to the seabed, where oxygen is consumed, was separated from the surface layer. The problem worsens if similar conditions restricting vertical transport of oxygen occur more frequently in the future.
Justin C. Tiano, Jochen Depestele, Gert Van Hoey, João Fernandes, Pieter van Rijswijk, and Karline Soetaert
Biogeosciences, 19, 2583–2598, https://doi.org/10.5194/bg-19-2583-2022, https://doi.org/10.5194/bg-19-2583-2022, 2022
Short summary
Short summary
This study gives an assessment of bottom trawling on physical, chemical, and biological characteristics in a location known for its strong currents and variable habitats. Although trawl gears only removed the top 1 cm of the seabed surface, impacts on reef-building tubeworms significantly decreased carbon and nutrient cycling. Lighter trawls slightly reduced the impact on fauna and nutrients. Tubeworms were strongly linked to biogeochemical and faunal aspects before but not after trawling.
Inda Brinkmann, Christine Barras, Tom Jilbert, Tomas Næraa, K. Mareike Paul, Magali Schweizer, and Helena L. Filipsson
Biogeosciences, 19, 2523–2535, https://doi.org/10.5194/bg-19-2523-2022, https://doi.org/10.5194/bg-19-2523-2022, 2022
Short summary
Short summary
The concentration of the trace metal barium (Ba) in coastal seawater is a function of continental input, such as riverine discharge. Our geochemical records of the severely hot and dry year 2018, and following wet year 2019, reveal that prolonged drought imprints with exceptionally low Ba concentrations in benthic foraminiferal calcium carbonates of coastal sediments. This highlights the potential of benthic Ba / Ca to trace past climate extremes and variability in coastal marine records.
Shichao Tian, Birgit Gaye, Jianhui Tang, Yongming Luo, Wenguo Li, Niko Lahajnar, Kirstin Dähnke, Tina Sanders, Tianqi Xiong, Weidong Zhai, and Kay-Christian Emeis
Biogeosciences, 19, 2397–2415, https://doi.org/10.5194/bg-19-2397-2022, https://doi.org/10.5194/bg-19-2397-2022, 2022
Short summary
Short summary
We constrain the nitrogen budget and in particular the internal sources and sinks of nitrate in the Bohai Sea by using a mass-based and dual stable isotope approach based on δ15N and δ18O of nitrate. Based on available mass fluxes and isotope data an updated nitrogen budget is proposed. Compared to previous estimates, it is more complete and includes the impact of the interior cycle (nitrification) on the nitrate pool. The main external nitrogen sources are rivers contributing 19.2 %–25.6 %.
Gesa Schulz, Tina Sanders, Justus E. E. van Beusekom, Yoana G. Voynova, Andreas Schöl, and Kirstin Dähnke
Biogeosciences, 19, 2007–2024, https://doi.org/10.5194/bg-19-2007-2022, https://doi.org/10.5194/bg-19-2007-2022, 2022
Short summary
Short summary
Estuaries can significantly alter nutrient loads before reaching coastal waters. Our study of the heavily managed Ems estuary (Northern Germany) reveals three zones of nitrogen turnover along the estuary with water-column denitrification in the most upstream hyper-turbid part, nitrate production in the middle reaches and mixing/nitrate uptake in the North Sea. Suspended particulate matter was the overarching control on nitrogen cycling in the hyper-turbid estuary.
Wiley Evans, Geoffrey T. Lebon, Christen D. Harrington, Yuichiro Takeshita, and Allison Bidlack
Biogeosciences, 19, 1277–1301, https://doi.org/10.5194/bg-19-1277-2022, https://doi.org/10.5194/bg-19-1277-2022, 2022
Short summary
Short summary
Information on the marine carbon dioxide system along the northeast Pacific Inside Passage has been limited. To address this gap, we instrumented an Alaskan ferry in order to characterize the marine carbon dioxide system in this region. Data over a 2-year period were used to assess drivers of the observed variability, identify the timing of severe conditions, and assess the extent of contemporary ocean acidification as well as future levels consistent with a 1.5 °C warmer climate.
Melissa Ward, Tye L. Kindinger, Heidi K. Hirsh, Tessa M. Hill, Brittany M. Jellison, Sarah Lummis, Emily B. Rivest, George G. Waldbusser, Brian Gaylord, and Kristy J. Kroeker
Biogeosciences, 19, 689–699, https://doi.org/10.5194/bg-19-689-2022, https://doi.org/10.5194/bg-19-689-2022, 2022
Short summary
Short summary
Here, we synthesize the results from 62 studies reporting in situ rates of seagrass metabolism to highlight spatial and temporal variability in oxygen fluxes and inform efforts to use seagrass to mitigate ocean acidification. Our analyses suggest seagrass meadows are generally autotrophic and variable in space and time, and the effects on seawater oxygen are relatively small in magnitude.
Tianfei Xue, Ivy Frenger, A. E. Friederike Prowe, Yonss Saranga José, and Andreas Oschlies
Biogeosciences, 19, 455–475, https://doi.org/10.5194/bg-19-455-2022, https://doi.org/10.5194/bg-19-455-2022, 2022
Short summary
Short summary
The Peruvian system supports 10 % of the world's fishing yield. In the Peruvian system, wind and earth’s rotation bring cold, nutrient-rich water to the surface and allow phytoplankton to grow. But observations show that it grows worse at high upwelling. Using a model, we find that high upwelling happens when air mixes the water the most. Then phytoplankton is diluted and grows slowly due to low light and cool upwelled water. This study helps to estimate how it might change in a warming climate.
Shao-Min Chen, Ulf Riebesell, Kai G. Schulz, Elisabeth von der Esch, Eric P. Achterberg, and Lennart T. Bach
Biogeosciences, 19, 295–312, https://doi.org/10.5194/bg-19-295-2022, https://doi.org/10.5194/bg-19-295-2022, 2022
Short summary
Short summary
Oxygen minimum zones in the ocean are characterized by enhanced carbon dioxide (CO2) levels and are being further acidified by increasing anthropogenic atmospheric CO2. Here we report CO2 system measurements in a mesocosm study offshore Peru during a rare coastal El Niño event to investigate how CO2 dynamics may respond to ongoing ocean deoxygenation. Our observations show that nitrogen limitation, productivity, and plankton community shift play an important role in driving the CO2 dynamics.
Paula Maria Salgado-Hernanz, Aurore Regaudie-de-Gioux, David Antoine, and Gotzon Basterretxea
Biogeosciences, 19, 47–69, https://doi.org/10.5194/bg-19-47-2022, https://doi.org/10.5194/bg-19-47-2022, 2022
Short summary
Short summary
For the first time, this study presents the characteristics of primary production in coastal regions of the Mediterranean Sea based on satellite-borne observations for the period 2002–2016. The study concludes that there are significant spatial and temporal variations among different regions. Quantifying primary production is of special importance in the marine food web and in the sequestration of carbon dioxide from the atmosphere to the deep waters.
Samu Elovaara, Eeva Eronen-Rasimus, Eero Asmala, Tobias Tamelander, and Hermanni Kaartokallio
Biogeosciences, 18, 6589–6616, https://doi.org/10.5194/bg-18-6589-2021, https://doi.org/10.5194/bg-18-6589-2021, 2021
Short summary
Short summary
Dissolved organic matter (DOM) is a significant carbon pool in the marine environment. The composition of the DOM pool, as well as its interaction with microbes, is complex, yet understanding it is important for understanding global carbon cycling. This study shows that two phytoplankton species have different effects on the composition of the DOM pool and, through the DOM they produce, on the ensuing microbial community. These communities in turn have different effects on DOM composition.
Yuan Dong, Qian P. Li, Zhengchao Wu, Yiping Shuai, Zijia Liu, Zaiming Ge, Weiwen Zhou, and Yinchao Chen
Biogeosciences, 18, 6423–6434, https://doi.org/10.5194/bg-18-6423-2021, https://doi.org/10.5194/bg-18-6423-2021, 2021
Short summary
Short summary
Temporal change of plankton growth and grazing are less known in the coastal ocean, not to mention the relevant controlling mechanisms. Here, we performed monthly size-specific dilution experiments outside a eutrophic estuary over a 1-year cycle. Phytoplankton growth was correlated to nutrients and grazing mortality to total chlorophyll a. A selective grazing on small cells may be important for maintaining high abundance of large-chain-forming diatoms in this eutrophic system.
Kiefer O. Forsch, Lisa Hahn-Woernle, Robert M. Sherrell, Vincent J. Roccanova, Kaixuan Bu, David Burdige, Maria Vernet, and Katherine A. Barbeau
Biogeosciences, 18, 6349–6375, https://doi.org/10.5194/bg-18-6349-2021, https://doi.org/10.5194/bg-18-6349-2021, 2021
Short summary
Short summary
We show that for an unperturbed cold western Antarctic Peninsula fjord, the seasonality of iron and manganese is linked to the dispersal of metal-rich meltwater sources. Geochemical measurements of trace metals in meltwaters, porewaters, and seawater, collected during two expeditions, showed a seasonal cycle of distinct sources. Finally, model results revealed that the dispersal of surface meltwater and meltwater plumes originating from under the glacier is sensitive to katabatic wind events.
Jenny Hieronymus, Kari Eilola, Malin Olofsson, Inga Hense, H. E. Markus Meier, and Elin Almroth-Rosell
Biogeosciences, 18, 6213–6227, https://doi.org/10.5194/bg-18-6213-2021, https://doi.org/10.5194/bg-18-6213-2021, 2021
Short summary
Short summary
Dense blooms of cyanobacteria occur every summer in the Baltic Proper and can add to eutrophication by their ability to turn nitrogen gas into dissolved inorganic nitrogen. Being able to correctly estimate the size of this nitrogen fixation is important for management purposes. In this work, we find that the life cycle of cyanobacteria plays an important role in capturing the seasonality of the blooms as well as the size of nitrogen fixation in our ocean model.
Tom Hull, Naomi Greenwood, Antony Birchill, Alexander Beaton, Matthew Palmer, and Jan Kaiser
Biogeosciences, 18, 6167–6180, https://doi.org/10.5194/bg-18-6167-2021, https://doi.org/10.5194/bg-18-6167-2021, 2021
Short summary
Short summary
The shallow shelf seas play a large role in the global cycling of CO2 and also support large fisheries. We use an autonomous underwater vehicle in the central North Sea to measure the rates of change in oxygen and nutrients.
Using these data we determine the amount of carbon dioxide taken out of the atmosphere by the sea and measure how productive the region is.
These observations will be useful for improving our predictive models and help us predict and adapt to a changing ocean.
Puthenveettil Narayana Menon Vinayachandran, Yukio Masumoto, Michael J. Roberts, Jenny A. Huggett, Issufo Halo, Abhisek Chatterjee, Prakash Amol, Garuda V. M. Gupta, Arvind Singh, Arnab Mukherjee, Satya Prakash, Lynnath E. Beckley, Eric Jorden Raes, and Raleigh Hood
Biogeosciences, 18, 5967–6029, https://doi.org/10.5194/bg-18-5967-2021, https://doi.org/10.5194/bg-18-5967-2021, 2021
Short summary
Short summary
Upwelling in the coastal ocean triggers biological productivity and thus enhances fisheries. Therefore, understanding the phenomenon of upwelling and the underlying mechanisms is important. In this paper, the present understanding of the upwelling along the coastline of the Indian Ocean from the coast of Africa all the way up to the coast of Australia is reviewed. The review provides a synthesis of the physical processes associated with upwelling and its impact on the marine ecosystem.
Gaël Many, Caroline Ulses, Claude Estournel, and Patrick Marsaleix
Biogeosciences, 18, 5513–5538, https://doi.org/10.5194/bg-18-5513-2021, https://doi.org/10.5194/bg-18-5513-2021, 2021
Short summary
Short summary
The Gulf of Lion shelf is one of the most productive areas in the Mediterranean. A model is used to study the mechanisms that drive the particulate organic carbon (POC). The model reproduces the annual cycle of primary production well. The shelf appears as an autotrophic ecosystem with a high production and as a source of POC for the adjacent basin. The increase in temperature induced by climate change could impact the trophic status of the shelf.
Alireza Merikhi, Peter Berg, and Markus Huettel
Biogeosciences, 18, 5381–5395, https://doi.org/10.5194/bg-18-5381-2021, https://doi.org/10.5194/bg-18-5381-2021, 2021
Short summary
Short summary
The aquatic eddy covariance technique is a powerful method for measurements of solute fluxes across the sediment–water interface. Data measured by conventional eddy covariance instruments require a time shift correction that can result in substantial flux errors. We introduce a triple O2 sensor eddy covariance instrument that by design eliminates these errors. Deployments next to a conventional instrument in the Florida Keys demonstrate the improvements achieved through the new design.
Jiatang Hu, Zhongren Zhang, Bin Wang, and Jia Huang
Biogeosciences, 18, 5247–5264, https://doi.org/10.5194/bg-18-5247-2021, https://doi.org/10.5194/bg-18-5247-2021, 2021
Short summary
Short summary
In situ observations over 42 years were used to explore the long-term changes to low-oxygen conditions in the Pearl River estuary. Apparent expansion of the low-oxygen conditions in summer was identified, primarily due to the combined effects of increased anthropogenic inputs and decreased sediment load. Large areas of severe low-oxygen events were also observed in early autumn and were formed by distinct mechanisms. The estuary seems to be growing into a seasonal, estuary-wide hypoxic zone.
Indah Ardiningsih, Kyyas Seyitmuhammedov, Sylvia G. Sander, Claudine H. Stirling, Gert-Jan Reichart, Kevin R. Arrigo, Loes J. A. Gerringa, and Rob Middag
Biogeosciences, 18, 4587–4601, https://doi.org/10.5194/bg-18-4587-2021, https://doi.org/10.5194/bg-18-4587-2021, 2021
Short summary
Short summary
Organic Fe speciation is investigated along a natural gradient of the western Antarctic Peninsula from an ice-covered shelf to the open ocean. The two major fronts in the region affect the distribution of ligands. The excess ligands not bound to dissolved Fe (DFe) comprised up to 80 % of the total ligand concentrations, implying the potential to solubilize additional Fe input. The ligands on the shelf can increase the DFe residence time and fuel local primary production upon ice melt.
Melissa R. McCutcheon, Hongming Yao, Cory J. Staryk, and Xinping Hu
Biogeosciences, 18, 4571–4586, https://doi.org/10.5194/bg-18-4571-2021, https://doi.org/10.5194/bg-18-4571-2021, 2021
Short summary
Short summary
We used 5+ years of discrete samples and 10 months of hourly sensor measurements to explore temporal variability and environmental controls on pH and pCO2 at the Aransas Ship Channel. Seasonal and diel variability were both present but small compared to other regions in the literature. Despite the small tidal range, tidal control often surpassed biological control. In comparison with sensor data, discrete samples were generally representative of mean annual and seasonal carbonate chemistry.
Kai G. Schulz, Eric P. Achterberg, Javier Arístegui, Lennart T. Bach, Isabel Baños, Tim Boxhammer, Dirk Erler, Maricarmen Igarza, Verena Kalter, Andrea Ludwig, Carolin Löscher, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Elisabeth von der Esch, Bess B. Ward, and Ulf Riebesell
Biogeosciences, 18, 4305–4320, https://doi.org/10.5194/bg-18-4305-2021, https://doi.org/10.5194/bg-18-4305-2021, 2021
Short summary
Short summary
Upwelling of nutrient-rich deep waters to the surface make eastern boundary upwelling systems hot spots of marine productivity. This leads to subsurface oxygen depletion and the transformation of bioavailable nitrogen into inert N2. Here we quantify nitrogen loss processes following a simulated deep water upwelling. Denitrification was the dominant process, and budget calculations suggest that a significant portion of nitrogen that could be exported to depth is already lost in the surface ocean.
Heiner Dietze and Ulrike Löptien
Biogeosciences, 18, 4243–4264, https://doi.org/10.5194/bg-18-4243-2021, https://doi.org/10.5194/bg-18-4243-2021, 2021
Short summary
Short summary
In recent years fish-kill events caused by oxygen deficit have been reported in Eckernförde Bight (Baltic Sea). This study sets out to understand the processes causing respective oxygen deficits by combining high-resolution coupled ocean circulation biogeochemical modeling, monitoring data, and artificial intelligence.
Jens A. Hölemann, Bennet Juhls, Dorothea Bauch, Markus Janout, Boris P. Koch, and Birgit Heim
Biogeosciences, 18, 3637–3655, https://doi.org/10.5194/bg-18-3637-2021, https://doi.org/10.5194/bg-18-3637-2021, 2021
Short summary
Short summary
The Arctic Ocean receives large amounts of river water rich in terrestrial dissolved organic matter (tDOM), which is an important component of the Arctic carbon cycle. Our analysis shows that mixing of three major freshwater sources is the main factor that regulates the distribution of tDOM concentrations in the Siberian shelf seas. In this context, the formation and melting of the land-fast ice in the Laptev Sea and the peak spring discharge of the Lena River are of particular importance.
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
( ) Decay in the Eastern Tropical North Atlantic, Environ. Sci.
Technol., 47, 10249–10256, https://doi.org/10.1021/es401658t, 2013.
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...
Altmetrics
Final-revised paper
Preprint