Articles | Volume 16, issue 6
https://doi.org/10.5194/os-16-1347-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/os-16-1347-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
09 Nov 2020
Research article |
| 09 Nov 2020
| 09 Nov 2020
Influence of intraseasonal eastern boundary circulation variability on hydrography and biogeochemistry off Peru
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker
Weg 20, Kiel, Germany
Marcus Dengler
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker
Weg 20, Kiel, Germany
Stefan Sommer
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker
Weg 20, Kiel, Germany
David Clemens
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker
Weg 20, Kiel, Germany
Sören Thomsen
LOCEAN-IPSL, IRD/CNRS/Sorbonnes Universites (UPMC)/MNHN, UMR 7159,
Paris, France
Gerd Krahmann
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker
Weg 20, Kiel, Germany
Andrew W. Dale
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker
Weg 20, Kiel, Germany
Eric P. Achterberg
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker
Weg 20, Kiel, Germany
Faculty of Mathematics and Natural Sciences, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
Martin Visbeck
GEOMAR Helmholtz Centre for Ocean Research Kiel, Düsternbrooker
Weg 20, Kiel, Germany
Faculty of Mathematics and Natural Sciences, Christian-Albrechts-Universität zu Kiel, Kiel, Germany
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Ruifang C. Xie, Frédéric A. C. Le Moigne, Insa Rapp, Jan Lüdke, Beat Gasser, Marcus Dengler, Volker Liebetrau, and Eric P. Achterberg
Biogeosciences, 17, 4919–4936, https://doi.org/10.5194/bg-17-4919-2020, https://doi.org/10.5194/bg-17-4919-2020, 2020
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Lennart Thomas Bach, Allanah Joy Paul, Tim Boxhammer, Elisabeth von der Esch, Michelle Graco, Kai Georg Schulz, Eric Achterberg, Paulina Aguayo, Javier Arístegui, Patrizia Ayón, Isabel Baños, Avy Bernales, Anne Sophie Boegeholz, Francisco Chavez, Gabriela Chavez, Shao-Min Chen, Kristin Doering, Alba Filella, Martin Fischer, Patricia Grasse, Mathias Haunost, Jan Hennke, Nauzet Hernández-Hernández, Mark Hopwood, Maricarmen Igarza, Verena Kalter, Leila Kittu, Peter Kohnert, Jesus Ledesma, Christian Lieberum, Silke Lischka, Carolin Löscher, Andrea Ludwig, Ursula Mendoza, Jana Meyer, Judith Meyer, Fabrizio Minutolo, Joaquin Ortiz Cortes, Jonna Piiparinen, Claudia Sforna, Kristian Spilling, Sonia Sanchez, Carsten Spisla, Michael Sswat, Mabel Zavala Moreira, and Ulf Riebesell
Biogeosciences, 17, 4831–4852, https://doi.org/10.5194/bg-17-4831-2020, https://doi.org/10.5194/bg-17-4831-2020, 2020
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Alexandra N. Loginova, Andrew W. Dale, Frédéric A. C. Le Moigne, Sören Thomsen, Stefan Sommer, David Clemens, Klaus Wallmann, and Anja Engel
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Anna Plass, Christian Schlosser, Stefan Sommer, Andrew W. Dale, Eric P. Achterberg, and Florian Scholz
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Mark J. Hopwood, Dustin Carroll, Thorben Dunse, Andy Hodson, Johnna M. Holding, José L. Iriarte, Sofia Ribeiro, Eric P. Achterberg, Carolina Cantoni, Daniel F. Carlson, Melissa Chierici, Jennifer S. Clarke, Stefano Cozzi, Agneta Fransson, Thomas Juul-Pedersen, Mie H. S. Winding, and Lorenz Meire
The Cryosphere, 14, 1347–1383, https://doi.org/10.5194/tc-14-1347-2020, https://doi.org/10.5194/tc-14-1347-2020, 2020
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Mark J. Hopwood, Nicolas Sanchez, Despo Polyviou, Øystein Leiknes, Julián Alberto Gallego-Urrea, Eric P. Achterberg, Murat V. Ardelan, Javier Aristegui, Lennart Bach, Sengul Besiktepe, Yohann Heriot, Ioanna Kalantzi, Tuba Terbıyık Kurt, Ioulia Santi, Tatiana M. Tsagaraki, and David Turner
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Mark J. Hopwood, Carolina Santana-González, Julian Gallego-Urrea, Nicolas Sanchez, Eric P. Achterberg, Murat V. Ardelan, Martha Gledhill, Melchor González-Dávila, Linn Hoffmann, Øystein Leiknes, Juana Magdalena Santana-Casiano, Tatiana M. Tsagaraki, and David Turner
Biogeosciences, 17, 1327–1342, https://doi.org/10.5194/bg-17-1327-2020, https://doi.org/10.5194/bg-17-1327-2020, 2020
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Fe is an essential micronutrient. Fe(III)-organic species are thought to account for > 99 % of dissolved Fe in seawater. Here we quantified Fe(II) during experiments in Svalbard, Gran Canaria, and Patagonia. Fe(II) was always a measurable fraction of dissolved Fe up to 65 %. Furthermore, when Fe(II) was allowed to decay in the dark, it remained present longer than predicted by kinetic equations, suggesting that Fe(II) is a more important fraction of dissolved Fe in seawater than widely recognized.
Marie Maßmig, Jan Lüdke, Gerd Krahmann, and Anja Engel
Biogeosciences, 17, 215–230, https://doi.org/10.5194/bg-17-215-2020, https://doi.org/10.5194/bg-17-215-2020, 2020
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Little is known about the rates of bacterial element cycling in oxygen minimum zones (OMZs). We measured bacterial production and rates of extracellular hydrolytic enzymes at various in situ oxygen concentrations in the OMZ off Peru. Our field data show unhampered bacterial activity at low oxygen concentrations. Meanwhile bacterial degradation of organic matter substantially contributed to the formation of the OMZ.
Insa Rapp, Christian Schlosser, Jan-Lukas Menzel Barraqueta, Bernhard Wenzel, Jan Lüdke, Jan Scholten, Beat Gasser, Patrick Reichert, Martha Gledhill, Marcus Dengler, and Eric P. Achterberg
Biogeosciences, 16, 4157–4182, https://doi.org/10.5194/bg-16-4157-2019, https://doi.org/10.5194/bg-16-4157-2019, 2019
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The availability of iron (Fe) affects phytoplankton growth in large parts of the ocean. Shelf sediments, particularly in oxygen minimum zones, are a major source of Fe and other essential micronutrients, such as cobalt (Co) and manganese (Mn). We observed enhanced concentrations of Fe, Co, and Mn corresponding with low oxygen concentrations along the Mauritanian shelf, indicating that the projected future decrease in oxygen concentrations may result in increases in Fe, Mn, and Co concentrations.
Tronje P. Kemena, Angela Landolfi, Andreas Oschlies, Klaus Wallmann, and Andrew W. Dale
Earth Syst. Dynam., 10, 539–553, https://doi.org/10.5194/esd-10-539-2019, https://doi.org/10.5194/esd-10-539-2019, 2019
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Oceanic deoxygenation is driven by climate change in several areas of the global ocean. Measurements indicate that ocean volumes with very low oxygen levels expand, with consequences for marine organisms and fishery. We found climate-change-driven phosphorus (P) input in the ocean is hereby an important driver for deoxygenation on longer timescales with effects in the next millennia.
Tim Fischer, Annette Kock, Damian L. Arévalo-Martínez, Marcus Dengler, Peter Brandt, and Hermann W. Bange
Biogeosciences, 16, 2307–2328, https://doi.org/10.5194/bg-16-2307-2019, https://doi.org/10.5194/bg-16-2307-2019, 2019
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We investigated air–sea gas exchange in oceanic upwelling regions for the case of nitrous oxide off Peru. In this region, routine concentration measurements from ships at 5 m or 10 m depth prove to overestimate surface (bulk) concentration. Thus, standard estimates of gas exchange will show systematic error. This is due to very shallow stratified layers that inhibit exchange between surface water and waters below and can exist for several days. Maximum bias occurs in moderate wind conditions.
Alexandra N. Loginova, Sören Thomsen, Marcus Dengler, Jan Lüdke, and Anja Engel
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Henrike Schmidt, Rena Czeschel, and Martin Visbeck
Biogeosciences Discuss., https://doi.org/10.5194/bg-2019-168, https://doi.org/10.5194/bg-2019-168, 2019
Manuscript not accepted for further review
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Our investigations give a detailed insight on the changing current system at intermediate depth in the Arabian Sea and allow to draw conclusions on ventilation pathways of the oxygen minimum zone and its seasonal variability. In response to the monsoon system the boundary currents change direction and feature a regionally varying ventilation pattern.
Jan-Lukas Menzel Barraqueta, Jessica K. Klar, Martha Gledhill, Christian Schlosser, Rachel Shelley, Hélène F. Planquette, Bernhard Wenzel, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 16, 1525–1542, https://doi.org/10.5194/bg-16-1525-2019, https://doi.org/10.5194/bg-16-1525-2019, 2019
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We used surface water dissolved aluminium concentrations collected in four different GEOTRACES cruises to determine atmospheric deposition fluxes to the ocean. We calculate atmospheric deposition fluxes for largely under-sampled regions of the Atlantic Ocean and thus provide new constraints for models of atmospheric deposition. The use of the MADCOW model is of major importance as dissolved aluminium is analysed within the GEOTRACES project at high spatial resolution.
Soeren Thomsen, Johannes Karstensen, Rainer Kiko, Gerd Krahmann, Marcus Dengler, and Anja Engel
Biogeosciences, 16, 979–998, https://doi.org/10.5194/bg-16-979-2019, https://doi.org/10.5194/bg-16-979-2019, 2019
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Physical and biogeochemical observations from an autonomous underwater vehicle in combination with ship-based measurements are used to investigate remote and local drivers of the oxygen and nutrient variability off Mauritania. Beside the transport of oxygen and nutrients characteristics from remote areas towards Mauritania also local remineralization of organic material close to the seabed seems to be important for the distribution of oxygen and nutrients.
Géraldine Sarthou, Pascale Lherminier, Eric P. Achterberg, Fernando Alonso-Pérez, Eva Bucciarelli, Julia Boutorh, Vincent Bouvier, Edward A. Boyle, Pierre Branellec, Lidia I. Carracedo, Nuria Casacuberta, Maxi Castrillejo, Marie Cheize, Leonardo Contreira Pereira, Daniel Cossa, Nathalie Daniault, Emmanuel De Saint-Léger, Frank Dehairs, Feifei Deng, Floriane Desprez de Gésincourt, Jérémy Devesa, Lorna Foliot, Debany Fonseca-Batista, Morgane Gallinari, Maribel I. García-Ibáñez, Arthur Gourain, Emilie Grossteffan, Michel Hamon, Lars Eric Heimbürger, Gideon M. Henderson, Catherine Jeandel, Catherine Kermabon, François Lacan, Philippe Le Bot, Manon Le Goff, Emilie Le Roy, Alison Lefèbvre, Stéphane Leizour, Nolwenn Lemaitre, Pere Masqué, Olivier Ménage, Jan-Lukas Menzel Barraqueta, Herlé Mercier, Fabien Perault, Fiz F. Pérez, Hélène F. Planquette, Frédéric Planchon, Arnout Roukaerts, Virginie Sanial, Raphaëlle Sauzède, Catherine Schmechtig, Rachel U. Shelley, Gillian Stewart, Jill N. Sutton, Yi Tang, Nadine Tisnérat-Laborde, Manon Tonnard, Paul Tréguer, Pieter van Beek, Cheryl M. Zurbrick, and Patricia Zunino
Biogeosciences, 15, 7097–7109, https://doi.org/10.5194/bg-15-7097-2018, https://doi.org/10.5194/bg-15-7097-2018, 2018
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The GEOVIDE cruise (GEOTRACES Section GA01) was conducted in the North Atlantic Ocean and Labrador Sea in May–June 2014. In this special issue, results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among 17 articles. Here, the scientific context, project objectives, and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.
Jan-Lukas Menzel Barraqueta, Christian Schlosser, Hélène Planquette, Arthur Gourain, Marie Cheize, Julia Boutorh, Rachel Shelley, Leonardo Contreira Pereira, Martha Gledhill, Mark J. Hopwood, François Lacan, Pascale Lherminier, Geraldine Sarthou, and Eric P. Achterberg
Biogeosciences, 15, 5271–5286, https://doi.org/10.5194/bg-15-5271-2018, https://doi.org/10.5194/bg-15-5271-2018, 2018
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In the North Atlantic and Labrador Sea, low aerosol deposition and enhanced primary productivity control the dissolved aluminium (dAl) surface distribution, while remineralization of particles seems to control the distribution at depth. DAl in the ocean allows us to indirectly quantify the amount of dust deposited to a given region for a given period. Hence, the study of its distribution, cycling, sources, and sinks is of major importance to improve aerosol deposition models and climate models.
Christian Schlosser, Katrin Schmidt, Alfred Aquilina, William B. Homoky, Maxi Castrillejo, Rachel A. Mills, Matthew D. Patey, Sophie Fielding, Angus Atkinson, and Eric P. Achterberg
Biogeosciences, 15, 4973–4993, https://doi.org/10.5194/bg-15-4973-2018, https://doi.org/10.5194/bg-15-4973-2018, 2018
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Iron (Fe) emanating from the South Georgia shelf system fuels large phytoplankton blooms downstream of the island. However, the actual supply mechanisms of Fe are unclear. We found that shelf-sediment-derived iron and iron released from Antarctic krill control the Fe distribution in the shelf waters around South Georgia. The majority of the Fe appears to be derived from recycling of Fe-enriched particles that are transported with the water masses into the bloom region.
Konstantin Stolpovsky, Andrew W. Dale, and Klaus Wallmann
Biogeosciences, 15, 3391–3407, https://doi.org/10.5194/bg-15-3391-2018, https://doi.org/10.5194/bg-15-3391-2018, 2018
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The paper describes a new way to parameterize G-type models in marine sediments using data about reactivity of organic carbon sinking to the seafloor.
Eike E. Köhn, Sören Thomsen, Damian L. Arévalo-Martínez, and Torsten Kanzow
Ocean Sci., 13, 1017–1033, https://doi.org/10.5194/os-13-1017-2017, https://doi.org/10.5194/os-13-1017-2017, 2017
Johannes Hahn, Peter Brandt, Sunke Schmidtko, and Gerd Krahmann
Ocean Sci., 13, 551–576, https://doi.org/10.5194/os-13-551-2017, https://doi.org/10.5194/os-13-551-2017, 2017
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Recent studies have shown that the eastern tropical North Atlantic is subject to a strong decrease of the oceanic oxygen concentration in the upper 1000 m from the 1960s to today. By analyzing a broad observational data set, this study found an even stronger oxygen decrease in the upper 400 m throughout the past decade, whereas oxygen increase was found below (400–1000 m). Changes in the strength of the zonal currents are the most likely reason for the observed decadal oxygen changes.
Johannes Karstensen, Florian Schütte, Alice Pietri, Gerd Krahmann, Björn Fiedler, Damian Grundle, Helena Hauss, Arne Körtzinger, Carolin R. Löscher, Pierre Testor, Nuno Vieira, and Martin Visbeck
Biogeosciences, 14, 2167–2181, https://doi.org/10.5194/bg-14-2167-2017, https://doi.org/10.5194/bg-14-2167-2017, 2017
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High-resolution observational data from underwater gliders and ships are used to investigate drivers and pathways of nutrient upwelling in high-productive whirling ecosystems (eddies). The data suggest that the upwelling is created by the interaction of wind-induced internal waves with the local rotation of the eddy. Because of differences in nutrient and oxygen pathways, a low-oxygen core is established at shallow depth in the high-productive eddies.
Chris S. M. Turney, Christopher J. Fogwill, Jonathan G. Palmer, Erik van Sebille, Zoë Thomas, Matt McGlone, Sarah Richardson, Janet M. Wilmshurst, Pavla Fenwick, Violette Zunz, Hugues Goosse, Kerry-Jayne Wilson, Lionel Carter, Mathew Lipson, Richard T. Jones, Melanie Harsch, Graeme Clark, Ezequiel Marzinelli, Tracey Rogers, Eleanor Rainsley, Laura Ciasto, Stephanie Waterman, Elizabeth R. Thomas, and Martin Visbeck
Clim. Past, 13, 231–248, https://doi.org/10.5194/cp-13-231-2017, https://doi.org/10.5194/cp-13-231-2017, 2017
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The Southern Ocean plays a fundamental role in global climate but suffers from a dearth of observational data. As the Australasian Antarctic Expedition 2013–2014 we have developed the first annually resolved temperature record using trees from subantarctic southwest Pacific (52–54˚S) to extend the climate record back to 1870. With modelling we show today's high climate variability became established in the ~1940s and likely driven by a Rossby wave response originating from the tropical Pacific.
Thomas Hornick, Lennart T. Bach, Katharine J. Crawfurd, Kristian Spilling, Eric P. Achterberg, Jason N. Woodhouse, Kai G. Schulz, Corina P. D. Brussaard, Ulf Riebesell, and Hans-Peter Grossart
Biogeosciences, 14, 1–15, https://doi.org/10.5194/bg-14-1-2017, https://doi.org/10.5194/bg-14-1-2017, 2017
Kristian Spilling, Kai G. Schulz, Allanah J. Paul, Tim Boxhammer, Eric P. Achterberg, Thomas Hornick, Silke Lischka, Annegret Stuhr, Rafael Bermúdez, Jan Czerny, Kate Crawfurd, Corina P. D. Brussaard, Hans-Peter Grossart, and Ulf Riebesell
Biogeosciences, 13, 6081–6093, https://doi.org/10.5194/bg-13-6081-2016, https://doi.org/10.5194/bg-13-6081-2016, 2016
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We performed an experiment in the Baltic Sea in order to investigate the consequences of the increasing CO2 levels on biological processes in the free water mass. There was more accumulation of organic carbon at high CO2 levels. Surprisingly, this was caused by reduced loss processes (respiration and bacterial production) in a high-CO2 environment, and not by increased photosynthetic fixation of CO2. Our carbon budget can be used to better disentangle the effects of ocean acidification.
Florian Schütte, Johannes Karstensen, Gerd Krahmann, Helena Hauss, Björn Fiedler, Peter Brandt, Martin Visbeck, and Arne Körtzinger
Biogeosciences, 13, 5865–5881, https://doi.org/10.5194/bg-13-5865-2016, https://doi.org/10.5194/bg-13-5865-2016, 2016
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Mesoscale eddies with very low–oxygen concentrations at shallow depth have been recently discovered in the eastern tropical North Atlantic. Our analysis shows that low oxygen eddies occur more frequent than expected and are found even close to the equator (8° N). From budget calculations we show that an oxygen reduction of 7 µmol/kg in the depth range of 50–150 m in the eastern tropical North Atlantic (peak reduction is 16 µmol/kg at 100 m depth) can be associated with the dispersion of these eddies.
Jessica Gier, Stefan Sommer, Carolin R. Löscher, Andrew W. Dale, Ruth A. Schmitz, and Tina Treude
Biogeosciences, 13, 4065–4080, https://doi.org/10.5194/bg-13-4065-2016, https://doi.org/10.5194/bg-13-4065-2016, 2016
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Benthic nitrogen fixation and sulfate reduction were investigated in the Peruvian oxygen minimum zone. The data suggest a coupling of both activities to a large extent, but that also sulfide and organic matter availability are controlling the benthic diazotrophy in this area. The molecular analysis confirms the presence of heterotrophic diazotrophs. This work improves our understanding of N cycling in OMZ sediments and the understanding of N sources in the marine environment.
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
Carolin R. Löscher, Hermann W. Bange, Ruth A. Schmitz, Cameron M. Callbeck, Anja Engel, Helena Hauss, Torsten Kanzow, Rainer Kiko, Gaute Lavik, Alexandra Loginova, Frank Melzner, Judith Meyer, Sven C. Neulinger, Markus Pahlow, Ulf Riebesell, Harald Schunck, Sören Thomsen, and Hannes Wagner
Biogeosciences, 13, 3585–3606, https://doi.org/10.5194/bg-13-3585-2016, https://doi.org/10.5194/bg-13-3585-2016, 2016
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The ocean loses oxygen due to climate change. Addressing this issue in tropical ocean regions (off Peru and Mauritania), we aimed to understand the effects of oxygen depletion on various aspects of marine biogeochemistry, including primary production and export production, the nitrogen cycle, greenhouse gas production, organic matter fluxes and remineralization, and the role of zooplankton and viruses.
Matthew P. Humphreys, Florence M. Greatrix, Eithne Tynan, Eric P. Achterberg, Alex M. Griffiths, Claudia H. Fry, Rebecca Garley, Alison McDonald, and Adrian J. Boyce
Earth Syst. Sci. Data, 8, 221–233, https://doi.org/10.5194/essd-8-221-2016, https://doi.org/10.5194/essd-8-221-2016, 2016
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This paper reports the stable isotope composition of dissolved inorganic carbon in seawater for a transect from west to east across the North Atlantic Ocean. The results can be used to study oceanic uptake of anthropogenic carbon dioxide, and also to investigate the natural biological carbon pump. We also provide stable DIC isotope results for two batches of Dickson seawater CRMs to enable intercomparisons with other studies.
Monika Nausch, Lennart Thomas Bach, Jan Czerny, Josephine Goldstein, Hans-Peter Grossart, Dana Hellemann, Thomas Hornick, Eric Pieter Achterberg, Kai-Georg Schulz, and Ulf Riebesell
Biogeosciences, 13, 3035–3050, https://doi.org/10.5194/bg-13-3035-2016, https://doi.org/10.5194/bg-13-3035-2016, 2016
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Studies investigating the effect of increasing CO2 levels on the phosphorus cycle in natural waters are lacking although phosphorus often controls phytoplankton development in aquatic systems. The aim of our study was to analyse effects of elevated CO2 levels on phosphorus pool sizes and uptake. Therefore, we conducted a CO2-manipulation mesocosm experiment in the Storfjärden (western Gulf of Finland, Baltic Sea) in summer 2012. We compared the phosphorus dynamics in different mesocosm treatment
Pei-Chuan Chuang, Megan B. Young, Andrew W. Dale, Laurence G. Miller, Jorge A. Herrera-Silveira, and Adina Paytan
Biogeosciences, 13, 2981–3001, https://doi.org/10.5194/bg-13-2981-2016, https://doi.org/10.5194/bg-13-2981-2016, 2016
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A transport-reaction model was used to simulate porewater methane and sulfate concentrations. Model results and sediment slurry incubation experiments show high methane production rates supported by non-competitive substrates and ample dissolved and labile organic matter as well as methane from deeper sediment through bubbles dissolution and diffusion. The shallow methane production and accumulation depths in these sediments promote high methane fluxes to the water column and atmosphere.
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
Ulrike Lomnitz, Stefan Sommer, Andrew W. Dale, Carolin R. Löscher, Anna Noffke, Klaus Wallmann, and Christian Hensen
Biogeosciences, 13, 1367–1386, https://doi.org/10.5194/bg-13-1367-2016, https://doi.org/10.5194/bg-13-1367-2016, 2016
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The study presents a P budget including the P input from the water column, the P burial in the sediments, as well as the P release from the sediments. We found that the P input could not maintain the P release rates. Consideration of other P sources, e.g., terrigenous P and P released from the dissolution of Fe oxyhydroxides, showed that none of these can account for the missing P. Thus, it is likely that abundant sulfide-oxidizing bacteria release the missing P during our measurement period.
L. Stramma, R. Czeschel, T. Tanhua, P. Brandt, M. Visbeck, and B. S. Giese
Ocean Sci., 12, 153–167, https://doi.org/10.5194/os-12-153-2016, https://doi.org/10.5194/os-12-153-2016, 2016
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The subsurface circulation in the eastern tropical North Atlantic OMZ is derived from velocity, float and tracer data and data assimilation results, and shows a cyclonic flow around the Guinea Dome reaching into the oxygen minimum zone. The stronger cyclonic flow around the Guinea Dome in 2009 seem to be connected to a strong Atlantic Meridional Mode (AMM) event.
A continuous deoxygenation trend of the low oxygen layer was confirmed.
Eddy influence is weak south of the Cape Verde Islands.
J. Maltby, S. Sommer, A. W. Dale, and T. Treude
Biogeosciences, 13, 283–299, https://doi.org/10.5194/bg-13-283-2016, https://doi.org/10.5194/bg-13-283-2016, 2016
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The concurrence of methanogenesis and sulfate reduction was investigated in surface sediments (0–25cm b.s.f.) traversing the Peruvian margin. Surface methanogenesis was mainly based on non-competitive substrates to avoid competition with sulfate reducers. Accordingly, surface methanogenesis was mainly controlled by the availability of labile organic matter. The high relevance of surface methanogenesis especially on the shelf indicates its underestimated role within benthic methane budgeting.
R. Steinfeldt, J. Sültenfuß, M. Dengler, T. Fischer, and M. Rhein
Biogeosciences, 12, 7519–7533, https://doi.org/10.5194/bg-12-7519-2015, https://doi.org/10.5194/bg-12-7519-2015, 2015
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The coastal upwelling systems, e.g. off Peru and Mauritania,
are key regions for the emissions of climate relevant trace gases
from the ocean into the atmosphere. Here, gases and nutrients are
transported into the ocean mixed layer from below. The upwelling velocities,
however, are too small to be measured directly.
We use the enhancement of helium-3 in upwelled
waters to quantify the vertical velocity,
which varies between 1.0 and 2.5 metres per day in the coastal regions.
P. Steeb, S. Krause, P. Linke, C. Hensen, A. W. Dale, M. Nuzzo, and T. Treude
Biogeosciences, 12, 6687–6706, https://doi.org/10.5194/bg-12-6687-2015, https://doi.org/10.5194/bg-12-6687-2015, 2015
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We combined field, laboratory (sediment-flow-through system) and numerical modeling work to investigate cold seep sediments at Quespos Slide, offshore of Costa Rica. The results demonstrated the efficiency of the benthic methane filter and provided an estimate for its response time (ca. 170 days) to changes in fluid fluxes.
A. J. Paul, L. T. Bach, K.-G. Schulz, T. Boxhammer, J. Czerny, E. P. Achterberg, D. Hellemann, Y. Trense, M. Nausch, M. Sswat, and U. Riebesell
Biogeosciences, 12, 6181–6203, https://doi.org/10.5194/bg-12-6181-2015, https://doi.org/10.5194/bg-12-6181-2015, 2015
Y. Zhang, N. Mahowald, R. A. Scanza, E. Journet, K. Desboeufs, S. Albani, J. F. Kok, G. Zhuang, Y. Chen, D. D. Cohen, A. Paytan, M. D. Patey, E. P. Achterberg, J. P. Engelbrecht, and K. W. Fomba
Biogeosciences, 12, 5771–5792, https://doi.org/10.5194/bg-12-5771-2015, https://doi.org/10.5194/bg-12-5771-2015, 2015
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A new technique to determine a size-fractionated global soil elemental emission inventory based on a global soil and mineralogical data set is introduced. Spatial variability of mineral dust elemental fractions (8 elements, e.g., Ca, Fe, Al) is identified on a global scale, particularly for Ca. The Ca/Al ratio ranged between 0.1 and 5.0 and is confirmed as an indicator of dust source regions by a global dust model. Total and soluble dust element fluxes into different ocean basins are estimated.
M. P. Humphreys, E. P. Achterberg, A. M. Griffiths, A. McDonald, and A. J. Boyce
Earth Syst. Sci. Data, 7, 127–135, https://doi.org/10.5194/essd-7-127-2015, https://doi.org/10.5194/essd-7-127-2015, 2015
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We present measurements of the stable carbon isotope composition of seawater dissolved inorganic carbon. The samples were collected during two research cruises in boreal summer 2012 in the northeastern Atlantic and Nordic Seas. The results can be used to investigate the marine carbon cycle, providing information about biological productivity and oceanic uptake of anthropogenic carbon dioxide.
J. Karstensen, B. Fiedler, F. Schütte, P. Brandt, A. Körtzinger, G. Fischer, R. Zantopp, J. Hahn, M. Visbeck, and D. Wallace
Biogeosciences, 12, 2597–2605, https://doi.org/10.5194/bg-12-2597-2015, https://doi.org/10.5194/bg-12-2597-2015, 2015
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This study is the first report of the formation of dead zones in the open ocean. A combination of multiple ocean observing system elements (mooring, floats, satellites, ships) allowed us to reconstruct the generation of the dead zones and to connect the formation to enhanced respiration within mesoscale ocean eddies. The dead zones present specific threats to the ecosystem, such as the interruption of the diurnal migration of zooplankters.
A. W. Dale, S. Sommer, U. Lomnitz, I. Montes, T. Treude, V. Liebetrau, J. Gier, C. Hensen, M. Dengler, K. Stolpovsky, L. D. Bryant, and K. Wallmann
Biogeosciences, 12, 1537–1559, https://doi.org/10.5194/bg-12-1537-2015, https://doi.org/10.5194/bg-12-1537-2015, 2015
P. Brandt, H. W. Bange, D. Banyte, M. Dengler, S.-H. Didwischus, T. Fischer, R. J. Greatbatch, J. Hahn, T. Kanzow, J. Karstensen, A. Körtzinger, G. Krahmann, S. Schmidtko, L. Stramma, T. Tanhua, and M. Visbeck
Biogeosciences, 12, 489–512, https://doi.org/10.5194/bg-12-489-2015, https://doi.org/10.5194/bg-12-489-2015, 2015
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Our observational study looks at the structure of the eastern tropical North Atlantic (ETNA) oxygen minimum zone (OMZ) in comparison with the less-ventilated, eastern tropical South Pacific OMZ. We quantify the OMZ’s oxygen budget composed of consumption, advection, lateral and vertical mixing. Substantial oxygen variability is observed on interannual to multidecadal timescales. The deoxygenation of the ETNA OMZ during the last decades represents a substantial imbalance of the oxygen budget.
J. Friedrich, F. Janssen, D. Aleynik, H. W. Bange, N. Boltacheva, M. N. Çagatay, A. W. Dale, G. Etiope, Z. Erdem, M. Geraga, A. Gilli, M. T. Gomoiu, P. O. J. Hall, D. Hansson, Y. He, M. Holtappels, M. K. Kirf, M. Kononets, S. Konovalov, A. Lichtschlag, D. M. Livingstone, G. Marinaro, S. Mazlumyan, S. Naeher, R. P. North, G. Papatheodorou, O. Pfannkuche, R. Prien, G. Rehder, C. J. Schubert, T. Soltwedel, S. Sommer, H. Stahl, E. V. Stanev, A. Teaca, A. Tengberg, C. Waldmann, B. Wehrli, and F. Wenzhöfer
Biogeosciences, 11, 1215–1259, https://doi.org/10.5194/bg-11-1215-2014, https://doi.org/10.5194/bg-11-1215-2014, 2014
S. Krause, P. Steeb, C. Hensen, V. Liebetrau, A. W. Dale, M. Nuzzo, and T. Treude
Biogeosciences, 11, 507–523, https://doi.org/10.5194/bg-11-507-2014, https://doi.org/10.5194/bg-11-507-2014, 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
N. Glock, J. Schönfeld, A. Eisenhauer, C. Hensen, J. Mallon, and S. Sommer
Biogeosciences, 10, 4767–4783, https://doi.org/10.5194/bg-10-4767-2013, https://doi.org/10.5194/bg-10-4767-2013, 2013
V. J. Bertics, C. R. Löscher, I. Salonen, A. W. Dale, J. Gier, R. A. Schmitz, and T. Treude
Biogeosciences, 10, 1243–1258, https://doi.org/10.5194/bg-10-1243-2013, https://doi.org/10.5194/bg-10-1243-2013, 2013
A. W. Dale, V. J. Bertics, T. Treude, S. Sommer, and K. Wallmann
Biogeosciences, 10, 629–651, https://doi.org/10.5194/bg-10-629-2013, https://doi.org/10.5194/bg-10-629-2013, 2013
K. Soetaert, D. van Oevelen, and S. Sommer
Biogeosciences, 9, 5341–5352, https://doi.org/10.5194/bg-9-5341-2012, https://doi.org/10.5194/bg-9-5341-2012, 2012
Related subject area
Approach: In situ Observations | Depth range: Thermocline | Geographical range: Deep Seas: South Pacific | Phenomena: Temperature, Salinity and Density Fields
Transport, properties, and life cycles of mesoscale eddies in the eastern tropical South Pacific
Observed El Niño conditions in the eastern tropical Pacific in October 2015
Rena Czeschel, Florian Schütte, Robert A. Weller, and Lothar Stramma
Ocean Sci., 14, 731–750, https://doi.org/10.5194/os-14-731-2018, https://doi.org/10.5194/os-14-731-2018, 2018
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The mean circulation on the poleward side of the oxygen minimum zone is overlain by eddy activity playing an important role in the distribution of water masses and oxygen within the OMZ. The activity of different types of eddies was investigated during their westward propagation from the formation area off Peru/Chile into the open ocean. The focus was on the development of eddies, seasonal conditions during their formation, and the change of water mass properties transported within the eddies.
Lothar Stramma, Tim Fischer, Damian S. Grundle, Gerd Krahmann, Hermann W. Bange, and Christa A. Marandino
Ocean Sci., 12, 861–873, https://doi.org/10.5194/os-12-861-2016, https://doi.org/10.5194/os-12-861-2016, 2016
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Results from a research cruise on R/V Sonne to the eastern tropical Pacific in October 2015 during the 2015–2016 El Niño show the transition of current, hydrographic, and nutrient conditions to El Niño conditions in the eastern tropical Pacific in October 2015. Although in early 2015 the El Niño was strong and in October 2015 showed a clear El Niño influence on the EUC, in the eastern tropical Pacific the measurements only showed developing El Niño water mass distributions.
Cited articles
Albert, A., Echevin, V., Lévy, M., and Aumont, O.: Impact of nearshore
wind stress curl on coastal circulation and primary productivity in the Peru
upwelling system, J. Geophys. Res.-Oceans, 115, C12033, https://doi.org/10.1029/2010JC006569, 2010.
Bachèlery, M.-L., Illig, S., and Dadou, I.: Forcings of nutrient,
oxygen, and primary production interannual variability in the southeast
Atlantic Ocean, Geophys. Res. Lett., 43, 8617–8625,
https://doi.org/10.1002/2016gl070288, 2016.
Bakun, A. and Nelson, C. S.: The Seasonal Cycle of Wind-Stress Curl in
Subtropical Eastern Boundary Current Regions, J. Phys. Oceanogr., 21,
1815–1834, https://doi.org/10.1175/1520-0485(1991)021<1815:TSCOWS>2.0.CO;2, 1991.
Becker, J. J., Sandwell, D. T., Smith, W. H. F., Braud, J., Binder, B.,
Depner, J., Fabre, D., Factor, J., Ingalls, S., Kim, S.-H., Ladner, R.,
Marks, K., Nelson, S., Pharaoh, A., Trimmer, R., Rosenberg, J. V., Wallace,
G., and Weatherall, P.: Global Bathymetry and Elevation Data at 30 Arc
Seconds Resolution: SRTM30_PLUS, Mar. Geod., 32,
355–371, https://doi.org/10.1080/01490410903297766, 2009.
Belmadani, A., Echevin, V., Dewitte, B., and Colas, F.: Equatorially forced
intraseasonal propagations along the Peru-Chile coast and their relation
with the nearshore eddy activity in 1992–2000: A modeling study, J.
Geophys. Res.-Oceans, 117, C04025, https://doi.org/10.1029/2011JC007848, 2012.
Bentamy, A. and Fillon, D. C.: Gridded surface wind fields from Metop/ASCAT
measurements, Int. J. Remote Sens., 33, 1729–1754,
https://doi.org/10.1080/01431161.2011.600348, 2012.
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.
Brink, K. H.: A Comparison of Long Coastal Trapped Wave Theory with
Observations off Peru, J. Phys. Oceanogr., 12, 897–913,
https://doi.org/10.1175/1520-0485(1982)012<0897:ACOLCT>2.0.CO;2,
1982.
Brink, K. H.: Energy Conservation in Coastal-Trapped Wave Calculations, J.
Phys. Oceanogr., 19, 1011–1016, https://doi.org/10.1175/1520-0485(1989)019<1011:ECICTW>2.0.CO;2, 1989.
Brink, K. H.: Stable coastal-trapped waves with stratification, topography
and mean flow, MBLWHOI Library, Woods Hole, https://doi.org/10.1575/1912/10527, 2018.
Brink, K. H. and Chapman, D. C.: Programs for computing properties of
coastal-trapped waves and wind-driven motions over the continental shelf and
slope, WHOI Technical Reports, Woods Hole Oceanographic Institution in Woods Hole, https://doi.org/10.1575/1912/5368, 1987.
Brink, K. H., Halpern, D., and Smith, R. L.: Circulation in the Peruvian
upwelling system near 15∘ S, J. Geophys. Res., 85, 4036–4048,
https://doi.org/10.1029/jc085ic07p04036, 1980.
Brink, K. H., Halpern, D., Huyer, A., and Smith, R. L.: The physical
environment of the Peruvian upwelling system, Prog. Oceanogr., 12, 285–305,
https://doi.org/10.1016/0079-6611(83)90011-3, 1983.
Brunner, K., Rivas, D., and Lwiza, K. M. M.: Application of Classical Coastal
Trapped Wave Theory to High-Scattering Regions, J. Phys. Oceanogr., 49,
2201–2216, https://doi.org/10.1175/JPO-D-18-0112.1, 2019.
Callbeck, C. M., Lavik, G., Ferdelman, T. G., Fuchs, B., Gruber-Vodicka, H.
R., Hach, P. F., Littmann, S., Schoffelen, N. J., Kalvelage, T., Thomsen,
S., Schunck, H., Löscher, C. R., Schmitz, R. A., and Kuypers, M. M. M.:
Oxygen minimum zone cryptic sulfur cycling sustained by offshore transport
of key sulfur oxidizing bacteria, Nat. Commun., 9, 1729,
https://doi.org/10.1038/s41467-018-04041-x, 2018.
Carr, M.-E.: Estimation of potential productivity in Eastern Boundary
Currents using remote sensing, Deep Sea Res. Part II, 49, 59–80,
https://doi.org/10.1016/S0967-0645(01)00094-7, 2002.
Chaigneau, A., Dominguez, N., Eldin, G., Vasquez, L., Flores, R., Grados,
C., and Echevin, V.: Near-coastal circulation in the Northern Humboldt
Current System from shipboard ADCP data, J. Geophys. Res.-Oceans, 118,
5251–5266, https://doi.org/10.1002/jgrc.20328, 2013.
Chang, B. X., Devol, A. H., and Emerson, S. R.: Denitrification and the
nitrogen gas excess in the eastern tropical South Pacific oxygen deficient
zone, Deep Sea Res. Part I, 57, 1092–1101, https://doi.org/10.1016/j.dsr.2010.05.009,
2010.
Chavez, F. P., Bertrand, A., Guevara-Carrasco, R., Soler, P., and Csirke,
J.: The northern Humboldt Current System: Brief history, present status and
a view towards the future, Prog. Oceanogr., 79, 95–105,
https://doi.org/10.1016/j.pocean.2008.10.012, 2008.
Dale, A. W., Sommer, S., Lomnitz, U., Montes, I., Treude, T., Liebetrau, V., Gier, J., Hensen, C., Dengler, M., Stolpovsky, K., Bryant, L. D., and Wallmann, K.: Organic carbon production, mineralisation and preservation on the Peruvian margin, Biogeosciences, 12, 1537–1559, https://doi.org/10.5194/bg-12-1537-2015, 2015.
Dale, A. W., Sommer, S., Lomnitz, U., Bourbonnais, A., and Wallmann, K.:
Biological nitrate transport in sediments on the Peruvian margin mitigates
benthic sulfide emissions and drives pelagic N loss during stagnation
events, Deep Sea Res. Part I, 112, 123–136, https://doi.org/10.1016/j.dsr.2016.02.013,
2016.
Dengler, M. and Sommer, S.: Coupled benthic and pelagic oxygen, nutrient and
trace metal cycling, ventilation and carbon degradation in the oxygen
minimum zone of the Peruvian continental margin (SFB 754): Cruise No. M 136
11 April–3 May 2017 Callao (Peru) – Callao Solute-Flux Peru I,
METEOR-Berichte, https://doi.org/10.3289/CR_M136, 2019.
Dewitte, B., Illig, S., Renault, L., Goubanova, K., Takahashi, K.,
Gushchina, D., Mosquera, K., and Purca, S.: Modes of covariability between
sea surface temperature and wind stress intraseasonal anomalies along the
coast of Peru from satellite observations (2000–2008), J. Geophys. Res.-Oceans, 116, C04028, https://doi.org/10.1029/2010JC006495, 2011.
Echevin, V., Albert, A., Lévy, M., Graco, M., Aumont, O., Piétri,
A., and Garric, G.: Intraseasonal variability of nearshore productivity in
the Northern Humboldt Current System: The role of coastal trapped waves,
Cont. Shelf Res., 73, 14–30, https://doi.org/10.1016/j.csr.2013.11.015, 2014.
Echevin, V., Colas, F., Espinoza-Morriberon, D., Vasquez, L., Anculle, T.,
and Gutierrez, D.: Forcings and Evolution of the 2017 Coastal El Niño
Off Northern Peru and Ecuador, Front. Mar. Sci., 5, 367,
https://doi.org/10.3389/fmars.2018.00367, 2018.
Enfield, D. B., Cornejo-Rodriguez, M. D., Smith, R. L., and Newberger, P.
A.: The equatorial source of propagating variability along the Peru coast
during the 1982–1983 El Niño, J. Geophys. Res.-Oceans, 92, 14335–14346,
https://doi.org/10.1029/JC092iC13p14335, 1987.
Espinoza-Morriberón, D., Echevin, V., Colas, F., Tam, J., Ledesma, J., Vásquez, L., and Graco, M.: Impacts of El Niño events on the Peruvian upwelling system productivity, J. Geophys. Res.-Oceans, 122, 5423–5444, https://doi.org/10.1002/2016JC012439, 2017.
Espinoza-Morriberón, D., Echevin, V., Colas, F., Tam, J., Gutierrez, D.,
Graco, M., Ledesma, J., and Quispe-Ccalluari, C.: Oxygen Variability During
ENSO in the Tropical South Eastern Pacific, Front. Mar. Sci., 5, 526,
https://doi.org/10.3389/fmars.2018.00526, 2019.
Fennel, W., Junker, T., Schmidt, M., and Mohrholz, V.: Response of the
Benguela upwelling systems to spatial variations in the wind stress, Cont.
Shelf Res., 45, 65–77, https://doi.org/10.1016/j.csr.2012.06.004, 2012.
Fischer, J., Brandt, P., Dengler, M., Müller, M., and Symonds, D.:
Surveying the Upper Ocean with the Ocean Surveyor: A New Phased Array
Doppler Current Profiler, J. Atmos. Ocean. Tech., 20, 742–751,
https://doi.org/10.1175/1520-0426(2003)20<742:STUOWT>2.0.CO;2,
2003.
Garreaud, R. D.: A plausible atmospheric trigger for the 2017 coastal El
Niño, Int. J. Climatol., 38, e1296–e1302, https://doi.org/10.1002/joc.5426, 2018.
Graco, M. I., Purca, S., Dewitte, B., Castro, C. G., Morón, O., Ledesma, J., Flores, G., and Gutiérrez, D.: The OMZ and nutrient features as a signature of interannual and low-frequency variability in the Peruvian upwelling system, Biogeosciences, 14, 4601–4617, https://doi.org/10.5194/bg-14-4601-2017, 2017.
Grados, C., Chaigneau, A., Echevin, V., and Dominguez, N.: Upper ocean
hydrology of the Northern Humboldt Current System at seasonal, interannual
and interdecadal scales, Prog. Oceanogr., 165, 123–144,
https://doi.org/10.1016/j.pocean.2018.05.005, 2018.
Grasshoff, K., Ehrhardt, M., and Kremling, K.: Methods of seawater analysis, 63–72, Verlag Chemie, Weinheim, ISBN 3-527-25998-8, 1983.
Gruber, N.: The marine nitrogen cycle: overview and challenges, in: Nitrogen
in the marine environment, vol. 2, edited by: Capone, D. G., Bronk, D. A., Mulholland, M., and Carpenter, E. J., pp. 1–50, Elsevier Amsterdam., ISBN 978-0-12-372522-6, 2008.
Gruber, N. and Sarmiento, J. L.: Global patterns of marine nitrogen fixation
and denitrification, Global Biogeochem. Cy., 11, 235–266,
https://doi.org/10.1029/97GB00077, 1997.
Gruber, N. and Sarmiento, J. L.: Large-scale biogeochemical-physical
interactions in elemental cycles, in: THE SEA: Biological–Physical
Interactions in the Oceans, vol. 12, edited by: Robinson, A. R.,
McCarthy, J. J., and Rothschild, B. J., 337–399, Wiley, New York, ISBN 9780674017429, 2002.
Gunther, E. R.: A report on oceanographical investigations in the Peru
Coastal Current, Discovery Rep., 13, 107–276, 1936.
Gutiérrez, D., Enríquez, E., Purca, S., Quipúzcoa, L.,
Marquina, R., Flores, G., and Graco, M.: Oxygenation episodes on the
continental shelf of central Peru: Remote forcing and benthic ecosystem
response, Prog. Oceanogr., 79, 177–189,
https://doi.org/10.1016/j.pocean.2008.10.025, 2008.
Hauschildt, J., Thomsen, S., Echevin, V., Oschlies, A., José, Y. S., Krahmann, G., Bristow, L. A., and Lavik, G.: The fate of upwelled nitrate off Peru shaped by submesoscale filaments and fronts, Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-112, in review, 2020.
Helly, J. J. and Levin, L. A.: Global distribution of naturally occurring
marine hypoxia on continental margins, Deep Sea Res. Part I, 51, 1159–1168,
https://doi.org/10.1016/j.dsr.2004.03.009, 2004.
Hill, A. E., Hickey, B. M., Shillington, F. A., Strub, P. T., Brink, K. H.,
Barton, E. D., and Thomas, A. C.: Eastern Ocean Boundaries, in: The Seas: The
Global Coastal Ocean, vol. 11, edited by: Robinson, A. R. and Brink, K. H., pp. 29–68, John Wiley, New York, ISBN 0-471-11545-2, 1998.
Holmes, R. M., Aminot, A., Kérouel, R., Hooker, B. A., and Peterson, B.
J.: A simple and precise method for measuring ammonium in marine and
freshwater ecosystems, Can. J. Fish. Aquat. Sci., 56, 1801–1808,
https://doi.org/10.1139/f99-128, 1999.
Hood, E. M., Sabine, C. L., and Sloyan, B. M.: The GO-SHIP Repeat Hydrography
Manual: a collection of expert reports and guidelines, Version 1, IOCCP
Report 14, ICPO Publication Series 134, 2010.
Hormazabal, S., Shaffer, G., and Pizarro, O.: Tropical Pacific control of
intraseasonal oscillations off Chile by way of oceanic and atmospheric
pathways, Geophys. Res. Lett., 29, 51–54, https://doi.org/10.1029/2001GL013481, 2002.
Huang, B., Thorne, P. W., Banzon, V. F., Boyer, T., Chepurin, G., Lawrimore,
J. H., Menne, M. J., Smith, T. M., Vose, R. S., and Zhang, H.-M.: NOAA
Extended Reconstructed Sea Surface Temperature (ERSST), Version 5,
https://doi.org/10.7289/V5T72FNM, 2017a.
Huang, B., Thorne, P. W., Banzon, V. F., Boyer, T., Chepurin, G., Lawrimore,
J. H., Menne, M. J., Smith, T. M., Vose, R. S., and Zhang, H.-M.: Extended
Reconstructed Sea Surface Temperature, Version 5 (ERSSTv5): Upgrades,
Validations, and Intercomparisons, J. Climate, 30, 8179–8205,
https://doi.org/10.1175/JCLI-D-16-0836.1, 2017b.
Illig, S., Dewitte, B., Goubanova, K., Cambon, G., Boucharel, J., Monetti,
F., Romero, C., Purca, S., and Flores, R.: Forcing mechanisms of
intraseasonal SST variability off central Peru in 2000–2008, J. Geophys. Res.-Oceans, 119, 3548–3573, https://doi.org/10.1002/2013JC009779, 2014.
Illig, S., Cadier, E., Bachèlery, M.-L., and Kersalé, M.:
Subseasonal Coastal-Trapped Wave Propagations in the Southeastern Pacific
and Atlantic Oceans: 1. A New Approach to Estimate Wave Amplitude, J. Geophys. Res.-Oceans, 123, 3915–3941, https://doi.org/10.1029/2017JC013539, 2018a.
Illig, S., Bachèlery, M.-L., and Cadier, E.: Subseasonal Coastal-Trapped
Wave Propagations in the Southeastern Pacific and Atlantic Oceans: 2. Wave
Characteristics and Connection With the Equatorial Variability, J. Geophys. Res.-Oceans, 123, 3942–3961, https://doi.org/10.1029/2017JC013540, 2018b.
Junker, T., Schmidt, M., and Mohrholz, V.: The relation of wind stress curl
and meridional transport in the Benguela upwelling system, J. Mar. Syst.,
143, 1–6, https://doi.org/10.1016/j.jmarsys.2014.10.006, 2015.
Kalvelage, T., Lavik, G., Lam, P., Contreras, S., Arteaga, L., Löscher,
C. R., Oschlies, A., Paulmier, A., Stramma, L., and Kuypers, M. M.: Nitrogen
cycling driven by organic matter export in the South Pacific oxygen minimum
zone, Nat. Geosci., 6, 228–234, https://doi.org/10.1038/ngeo1739, 2013.
Kämpf, J.: On the Dynamics of Canyon-Flow Interactions, Journal of Marine Science and Engineering,
6, 129, https://doi.org/10.3390/jmse6040129, 2018.
Kämpf, J. and Chapman, P.: Upwelling Systems of the World: A Scientific
Journey to the Most Productive Marine Ecosystems, Springer, Cham, ISBN 978-3-319-42522-1, 2016.
Karstensen, J., Schütte, F., Pietri, A., Krahmann, G., Fiedler, B., Grundle, D., Hauss, H., Körtzinger, A.,
Löscher, C. R., Testor, P., Vieira, N., and Visbeck, M.: Upwelling and isolation in oxygen-depleted anticyclonic
modewater eddies and implications for nitrate cycling, Biogeosciences, 14, 2167–2181, https://doi.org/10.5194/bg-14-2167-2017, 2017.
Klenz, T., Dengler, M., and Brandt, P.: Seasonal Variability of the
Mauritania Current and Hydrography at 18∘ N, J. Geophys. Res.-Oceans, 123, 8122–8137, https://doi.org/10.1029/2018jc014264, 2018.
Kuypers, M. M. M., Lavik, G., Woebken, D., Schmid, M., Fuchs, B. M., Amann,
R., Jørgensen, B. B., and Jetten, M. S. M.: Massive nitrogen loss from the
Benguela upwelling system through anaerobic ammonium oxidation, P. Natl. Acad. Sci., 102, 6478–6483,
https://doi.org/10.1073/pnas.0502088102, 2005.
Lam, P., Lavik, G., Jensen, M. M., van de Vossenberg, J., Schmid, M.,
Woebken, D., Gutiérrez, D., Amann, R., Jetten, M. S. M., and Kuypers, M.
M. M.: Revising the nitrogen cycle in the Peruvian oxygen minimum zone,
P. Natl. Acad. Sci., 106, 4752–4757,
https://doi.org/10.1073/pnas.0812444106, 2009.
Leth, O. and Middleton, J. F.: A numerical study of the upwelling
circulation off central Chile: Effects of remote oceanic forcing, J. Geophys. Res.-Oceans, 111, C12003, https://doi.org/10.1029/2005JC003070, 2006.
Levin, L., Gutiérrez, D., Rathburn, A., Neira, C., Sellanes, J.,
Muñoz, P., Gallardo, V., and Salamanca, M.: Benthic processes on the Peru
margin: a transect across the oxygen minimum zone during the 1997–1998 El
Niño, Prog. Oceanogr., 53, 1–27, https://doi.org/10.1016/S0079-6611(02)00022-8,
2002.
Lomnitz, U., Sommer, S., Dale, A. W., Löscher, C. R., Noffke, A., Wallmann, K., and Hensen, C.: Benthic phosphorus cycling in the Peruvian oxygen minimum zone, Biogeosciences, 13, 1367–1386, https://doi.org/10.5194/bg-13-1367-2016, 2016.
Lüdke, J., Dengler, M., Sommer, S., Clemens, D., Thomsen, S., Krahmann, G., Dale, A. W., Achterberg, E. P., and Visbeck, M.: Influence of intraseasonal eastern boundary circulation variability on hydrography and biogeochemistry off Peru, PANGAEA, https://doi.org/10.1594/PANGAEA.903828, 2019.
Marchesiello, P., McWilliams, J. C., and Shchepetkin, A.: Equilibrium
Structure and Dynamics of the California Current System, J. Phys. Oceanogr.,
33, 753–783, https://doi.org/10.1175/1520-0485(2003)33<753:ESADOT>2.0.CO;2, 2003.
McCreary, J. P. and Chao, S.-Y.: Three-dimensional shelf circulation along
an eastern ocean boundary, J. Mar. Res., 43, 13–36,
https://doi.org/10.1357/002224085788437316, 1985.
McDougall, T. J. and Barker, P. M.: Getting started with TEOS-10 and the
Gibbs Seawater (GSW) oceanographic toolbox, SCOR/IAPSO WG 127, ISBN 978-0-646-55621-5, 2011.
Montes, I., Colas, F., Capet, X., and Schneider, W.: On the pathways of the
equatorial subsurface currents in the eastern equatorial Pacific and their
contributions to the Peru-Chile Undercurrent, J. Geophys. Res.-Oceans, 115, C09003, https://doi.org/10.1029/2009JC005710, 2010.
Moore, D. W. and Philander, S. G. H.: Modelling of the tropical ocean
circulation, in The Sea, vol. 6, pp. 316–361, John Wiley, ISBN 0-471-31091-3, 1977.
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.
Peng, Q., Xie, S.-P., Wang, D., Zheng, X.-T., and Zhang, H.: Coupled ocean-atmosphere dynamics of the 2017 extreme coastal El Niño, Nat. Commun., 10, 298, https://doi.org/10.1038/s41467-018-08258-8, 2019.
Pennington, J. T., Mahoney, K. L., Kuwahara, V. S., Kolber, D. D., Calienes,
R., and Chavez, F. P.: Primary production in the eastern tropical Pacific: A
review, Prog. Oceanogr., 69, 285–317, https://doi.org/10.1016/j.pocean.2006.03.012,
2006.
Penven, P., Echevin, V., Pasapera, J., Colas, F., and Tam, J.: Average
circulation, seasonal cycle, and mesoscale dynamics of the Peru Current
System: A modeling approach, J. Geophys. Res.-Oceans, 110, C10021,
https://doi.org/10.1029/2005JC002945, 2005.
Philander, S. G. H. and Yoon, J.-H.: Eastern Boundary Currents and Coastal
Upwelling, J. Phys. Oceanogr., 12, 862–879,
https://doi.org/10.1175/1520-0485(1982)012<0862:EBCACU>2.0.CO;2,
1982.
Pizarro, O., Shaffer, G., Dewitte, B., and Ramos, M.: Dynamics of seasonal
and interannual variability of the Peru-Chile Undercurrent, Geophys. Res.
Lett., 29, 22-1–22-4, https://doi.org/10.1029/2002GL014790, 2002.
Revsbech, N. P., Larsen, L. H., Gundersen, J., Dalsgaard, T., Ulloa, O., and
Thamdrup, B.: Determination of ultra-low oxygen concentrations in oxygen
minimum zones by the STOX sensor, Limnol. Oceanogr.-Meth., 7, 371–381,
https://doi.org/10.4319/lom.2009.7.371, 2009.
Romea, R. D. and Smith, R. L.: Further Evidence for Coastal Trapped Waves
along the Peru Coast, J. Phys. Oceanogr., 13, 1341–1356,
https://doi.org/10.1175/1520-0485(1983)013<1341:FEFCTW>2.0.CO;2,
1983.
Sakamoto, C. M., Johnson, K. S., and Coletti, L. J.: Improved algorithm for
the computation of nitrate concentrations in seawater using an in situ
ultraviolet spectrophotometer, Limnol. Oceanogr.-Meth., 7, 132–143,
https://doi.org/10.4319/lom.2009.7.132, 2009.
Schunck, H., Lavik, G., Desai, D. K., Großkopf, T., Kalvelage, T.,
Löscher, C. R., Paulmier, A., Contreras, S., Siegel, H., Holtappels, M.,
Rosenstiel, P., Schilhabel, M. B., Graco, M., Schmitz, R. A., Kuypers, M. M.
M., and LaRoche, J.: Giant Hydrogen Sulfide Plume in the Oxygen Minimum Zone
off Peru Supports Chemolithoautotrophy, PLoS One, 8, 1–18,
https://doi.org/10.1371/journal.pone.0068661, 2013.
Shaffer, G., Pizarro, O., Djurfeldt, L., Salinas, S., and Rutllant, J.: Circulation and Low-Frequency Variability near the Chilean Coast:
Remotely Forced Fluctuations during the 1991–1992 El Niño, J.
Phys. Oceanogr., 27, 217–235, https://doi.org/10.1175/1520-0485(1997)027<0217:CALFVN>2.0.CO;2, 1997.
Silva, N., Rojas, N., and Fedele, A.: Water masses in the Humboldt Current
System: Properties, distribution, and the nitrate deficit as a chemical
water mass tracer for Equatorial Subsurface Water off Chile, Deep Sea Res.
Part II, 56, 1004–1020, https://doi.org/10.1016/j.dsr2.2008.12.013, 2009.
Sommer, S., Gier, J., Treude, T., Lomnitz, U., Dengler, M., Cardich, J., and
Dale, A. W.: Depletion of oxygen, nitrate and nitrite in the Peruvian oxygen
minimum zone cause an imbalance of benthic nitrogen fluxes, Deep Sea Res.
Part I, 112, 113–122, https://doi.org/10.1016/j.dsr.2016.03.001, 2016.
Sommer, S., Dengler, M., and Shipboard Scientific Party: Benthic element
cycling, fluxes and transport of nutrients and trace metals across the
benthic boundary layer in the Peruvian oxygen minimum zone (SFB 754), Cruise
No. 137, 6 May–29 May 2017, Callao (Peru) – Callao, METEOR-Berichte,
https://doi.org/10.2312/cr_m137, 2019.
Strub, P. T., Mesias, J. M., Montecino, V., Rutllant, J., and Salinas, S.:
Coastal ocean circulation off western South America, in: The Seas: The Global
Coastal Ocean, vol. 11, edited by: Robinson, A. R. and Brink, K. H., pp.
273–313, John Wiley, New York, ISBN 0-471-11545-2, 1998.
Thomsen, S., Kanzow, T., Krahmann, G., Greatbatch, R. J., Dengler, M., and
Lavik, G.: The formation of a subsurface anticyclonic eddy in the Peru-Chile
Undercurrent and its impact on the near-coastal salinity, oxygen, and
nutrient distributions, J. Geophys. Res.-Oceans, 121, 476–501,
https://doi.org/10.1002/2015JC010878, 2016.
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.
Thyng, K. M., Greene, C. A., Hetland, R. D., Zimmerle, H. M., and DiMarco, S.
F.: True Colors of Oceanography: Guidelines for Effective and Accurate
Colormap Selection, Oceanography, 29, 9–13, https://doi.org/10.5670/oceanog.2016.66, 2016.
Ulloa, O., Canfield, D. E., DeLong, E. F., Letelier, R. M., and Stewart, F.
J.: Microbial oceanography of anoxic oxygen minimum zones, P. Natl. Acad. Sci., 109, 15996–16003,
https://doi.org/10.1073/pnas.1205009109, 2012.
Wang, D.-P.: Diffraction of Continental Shelf Waves by Irregular Alongshore
Geometry, J. Phys. Oceanogr., 10, 1187–1199,
https://doi.org/10.1175/1520-0485(1980)010<1187:DOCSWB>2.0.CO;2,
1980.
Wilkin, J. L. and Chapman, D. C.: Scattering of Coastal-Trapped Waves
by Irregularities in Coastline and Topography, J. Phys. Oceanogr., 20,
396–421, https://doi.org/10.1175/1520-0485(1990)020<0396:SOCTWB>2.0.CO;2, 1990.
Winkler, L. W.: Die Bestimmung des im Wasser gelösten Sauerstoffes, Ber.
Dtsch. Chem. Ges., 21, 2843–2854, https://doi.org/10.1002/cber.188802102122, 1888.
Yoon, J.-H. and Philander, S. G. H.: The generation of coastal
undercurrents, J. Oceanogr. Soc. Jpn., 38, 215–224,
https://doi.org/10.1007/bf02111104, 1982.
Yu, X. and McPhaden, M. J.: Seasonal Variability in the Equatorial Pacific,
J. Phys. Oceanogr., 29, 925–947 https://doi.org/10.1175/1520-0485(1999)029<0925:SVITEP>2.0.CO;2, 1999.
Zamora, L. M., Oschlies, A., Bange, H. W., Huebert, K. B., Craig, J. D., Kock, A., and Löscher, C. R.: Nitrous oxide dynamics in low oxygen regions of the Pacific: insights from the MEMENTO database, Biogeosciences, 9, 5007–5022, https://doi.org/10.5194/bg-9-5007-2012, 2012.
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.
We analyse the intraseasonal variability of the alongshore circulation off Peru in early 2017,...
