Articles | Volume 17, issue 19
https://doi.org/10.5194/bg-17-4831-2020
© 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/bg-17-4831-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
12 Oct 2020
Research article | Highlight paper |
| 12 Oct 2020
| 12 Oct 2020
Factors controlling plankton community production, export flux, and particulate matter stoichiometry in the coastal upwelling system off Peru
Lennart Thomas Bach
CORRESPONDING AUTHOR
Institute for Marine and Antarctic Studies, University of Tasmania,
Hobart, Tasmania, Australia
Allanah Joy Paul
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Tim Boxhammer
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Elisabeth von der Esch
Institute of Hydrochemistry, Chair of Analytical Chemistry and Water Chemistry, Technical University of Munich, Munich, Germany
Michelle Graco
Direccióìn General de Investigaciones Oceanográficas y Cambio
Climático, Instituto del Mar del Perú (IMARPE), Callao, Peru
Kai Georg Schulz
Centre for Coastal Biogeochemistry, School of Environment, Science and Engineering, Southern Cross University, Lismore, New South Wales, Australia
Eric Achterberg
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Paulina Aguayo
Millennium Institute of Oceanography (IMO), Universidad de
Concepción, Concepción, Chile
Javier Arístegui
Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria ULPGC, Las Palmas, Spain
Patrizia Ayón
Direccióìn General de Investigaciones Oceanográficas y Cambio
Climático, Instituto del Mar del Perú (IMARPE), Callao, Peru
Isabel Baños
Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria ULPGC, Las Palmas, Spain
Avy Bernales
Direccióìn General de Investigaciones Oceanográficas y Cambio
Climático, Instituto del Mar del Perú (IMARPE), Callao, Peru
Anne Sophie Boegeholz
Institute of General Microbiology, Department of Biology,
Christian-Albrechts-Universität zu Kiel, Kiel, Germany
Francisco Chavez
Monterey Bay Aquarium Research Institute, Moss Landing, United States of America
Gabriela Chavez
Monterey Bay Aquarium Research Institute, Moss Landing, United States of America
Shao-Min Chen
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Department of Earth and Environmental Sciences, Dalhousie University, Halifax, Canada
Kristin Doering
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Department of Earth and Environmental Sciences, Dalhousie University, Halifax, Canada
Alba Filella
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Martin Fischer
Institute of General Microbiology, Department of Biology,
Christian-Albrechts-Universität zu Kiel, Kiel, Germany
Patricia Grasse
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
German Centre for Integrative Biodiversity Research (iDiv),
Halle-Jena-Leipzig, Germany
Mathias Haunost
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Jan Hennke
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Nauzet Hernández-Hernández
Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria ULPGC, Las Palmas, Spain
Mark Hopwood
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Maricarmen Igarza
Programa de Maestría en Ciencias del Mar, Universidad Peruana
Cayetano Heredia, Lima, Peru
Verena Kalter
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Department of Ocean Sciences, Memorial University of Newfoundland, Logy Bay, Newfoundland, Canada
Leila Kittu
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Peter Kohnert
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Jesus Ledesma
Direccióìn General de Investigaciones Oceanográficas y Cambio
Climático, Instituto del Mar del Perú (IMARPE), Callao, Peru
Christian Lieberum
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Silke Lischka
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Carolin Löscher
University of Southern Denmark, Odense, Denmark
Andrea Ludwig
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Ursula Mendoza
Direccióìn General de Investigaciones Oceanográficas y Cambio
Climático, Instituto del Mar del Perú (IMARPE), Callao, Peru
Jana Meyer
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Judith Meyer
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Fabrizio Minutolo
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Joaquin Ortiz Cortes
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Jonna Piiparinen
Marine Research Centre, Finnish Environment Institute, Helsinki,
Finland
Claudia Sforna
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Kristian Spilling
Marine Research Centre, Finnish Environment Institute, Helsinki,
Finland
Faculty of Engineering and Science, University of Agder,
Kristiansand, Norway
Sonia Sanchez
Direccióìn General de Investigaciones Oceanográficas y Cambio
Climático, Instituto del Mar del Perú (IMARPE), Callao, Peru
Carsten Spisla
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Michael Sswat
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Mabel Zavala Moreira
Escuela Superior Politécnica del Litoral, Guayaquil, Ecuador
Ulf Riebesell
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
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Librada Ramírez, Leonardo J. Pozzo-Pirotta, Aja Trebec, Víctor Manzanares-Vázquez, José L. Díez, Javier Arístegui, Ulf Riebesell, Stephen D. Archer, and María Segovia
Biogeosciences, 22, 1865–1886, https://doi.org/10.5194/bg-22-1865-2025, https://doi.org/10.5194/bg-22-1865-2025, 2025
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We studied the potential effects of increasing ocean alkalinity on a natural plankton community in subtropical waters of the Atlantic near Gran Canaria, Spain. Alkalinity is the capacity of water to resist acidification, and plankton are usually microscopic plants (phytoplankton) and animals (zooplankton), often less than 2.5 cm in length. This study suggests that increasing ocean alkalinity did not have a significant negative impact on the plankton community studied.
Anna Pedersen, Carolin R. Löscher, and Steffen M. Olsen
EGUsphere, https://doi.org/10.5194/egusphere-2025-1218, https://doi.org/10.5194/egusphere-2025-1218, 2025
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The North Atlantic plays a crucial role in absorbing atmospheric CO2, but its air-sea CO2 flux varies across time and space. Using historical climate model simulations, we investigate how physical and oceanic processes drive the variability. Our results show that sea ice, temperature, salinity, wind stress, and ocean circulation shape CO2 exchange, with short-term fluctuations playing a dominant role. Understanding these complex interactions is key to predicting future ocean carbon uptake.
Julieta Schneider, Ulf Riebesell, Charly André Moras, Laura Marín-Samper, Leila Kittu, Joaquín Ortíz-Cortes, and Kai George Schulz
EGUsphere, https://doi.org/10.5194/egusphere-2025-524, https://doi.org/10.5194/egusphere-2025-524, 2025
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Luis P. Valencia, Ángel Rodríguez-Santana, Borja Aguiar-Gonzaléz, Javier Arístegui, Xosé A. Álvarez-Salgado, Josep Coca, and Antonio Martínez-Marrero
EGUsphere, https://doi.org/10.5194/egusphere-2025-99, https://doi.org/10.5194/egusphere-2025-99, 2025
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Giulia Faucher, Mathias Haunost, Allanah Joy Paul, Anne Ulrike Christiane Tietz, and Ulf Riebesell
Biogeosciences, 22, 405–415, https://doi.org/10.5194/bg-22-405-2025, https://doi.org/10.5194/bg-22-405-2025, 2025
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Ocean alkalinity enhancement (OAE) is being evaluated for its capacity to absorb atmospheric CO2 in the ocean and store it long term to mitigate climate change. As researchers plan for field tests to gain insights into OAE, sharing knowledge on its environmental impact on marine ecosystems is urgent. Our study examined NaOH-induced OAE in Emiliania huxleyi, a key coccolithophore species, and found that the added total alkalinity (ΔTA) should stay below 600 µmol kg⁻¹ to avoid negative impacts.
Philipp Suessle, Jan Taucher, Silvan Urs Goldenberg, Moritz Baumann, Kristian Spilling, Andrea Noche-Ferreira, Mari Vanharanta, and Ulf Riebesell
Biogeosciences, 22, 71–86, https://doi.org/10.5194/bg-22-71-2025, https://doi.org/10.5194/bg-22-71-2025, 2025
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Ocean alkalinity enhancement (OAE) is a negative emission technology which may alter marine communities and the particle export they drive. Here, impacts of carbonate-based OAE on the flux and attenuation of sinking particles in an oligotrophic plankton community are presented. Whilst biological parameters remained unaffected, abiotic carbonate precipitation occurred. Among counteracting OAE’s efficiency, it influenced mineral ballasting and particle sinking velocities, requiring monitoring.
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, and Ulf Riebesell
Biogeosciences, 21, 5707–5724, https://doi.org/10.5194/bg-21-5707-2024, https://doi.org/10.5194/bg-21-5707-2024, 2024
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Isabell Schlangen, Elizabeth Leon-Palmero, Annabell Moser, Peihang Xu, Erik Laursen, and Carolin Regina Löscher
EGUsphere, https://doi.org/10.5194/egusphere-2024-3680, https://doi.org/10.5194/egusphere-2024-3680, 2024
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Jana Krause, Dustin Carroll, Juan Höfer, Jeremy Donaire, Eric P. Achterberg, Emilio Alarcón, Te Liu, Lorenz Meire, Kechen Zhu, and Mark J. Hopwood
The Cryosphere, 18, 5735–5752, https://doi.org/10.5194/tc-18-5735-2024, https://doi.org/10.5194/tc-18-5735-2024, 2024
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Here we analysed calved ice samples from both the Arctic and Antarctic to assess the variability in the composition of iceberg meltwater. Our results suggest that low concentrations of nitrate and phosphate in ice are primarily from the ice matrix, whereas sediment-rich layers impart a low concentration of silica and modest concentrations of iron and manganese. At a global scale, there are very limited differences in the nutrient composition of ice.
Niels Suitner, Giulia Faucher, Carl Lim, Julieta Schneider, Charly A. Moras, Ulf Riebesell, and Jens Hartmann
Biogeosciences, 21, 4587–4604, https://doi.org/10.5194/bg-21-4587-2024, https://doi.org/10.5194/bg-21-4587-2024, 2024
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Recent studies described the precipitation of carbonates as a result of alkalinity enhancement in seawater, which could adversely affect the carbon sequestration potential of ocean alkalinity enhancement (OAE) approaches. By conducting experiments in natural seawater, this study observed uniform patterns during the triggered runaway carbonate precipitation, which allow the prediction of safe and efficient local application levels of OAE scenarios.
Silvan Urs Goldenberg, Ulf Riebesell, Daniel Brüggemann, Gregor Börner, Michael Sswat, Arild Folkvord, Maria Couret, Synne Spjelkavik, Nicolás Sánchez, Cornelia Jaspers, and Marta Moyano
Biogeosciences, 21, 4521–4532, https://doi.org/10.5194/bg-21-4521-2024, https://doi.org/10.5194/bg-21-4521-2024, 2024
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Ocean alkalinity enhancement (OAE) is being evaluated as a carbon dioxide removal technology for climate change mitigation. With an experiment on species communities, we show that larval and juvenile fish can be resilient to the resulting perturbation of seawater. Fish may hence recruit successfully and continue to support fisheries' production in regions of OAE. Our findings help to establish an environmentally safe operating space for this ocean-based solution.
Sebastian I. Cantarero, Edgart Flores, Harry Allbrook, Paulina Aguayo, Cristian A. Vargas, John E. Tamanaha, J. Bentley C. Scholz, Lennart T. Bach, Carolin R. Löscher, Ulf Riebesell, Balaji Rajagopalan, Nadia Dildar, and Julio Sepúlveda
Biogeosciences, 21, 3927–3958, https://doi.org/10.5194/bg-21-3927-2024, https://doi.org/10.5194/bg-21-3927-2024, 2024
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Our study explores lipid remodeling in response to environmental stress, specifically how cell membrane chemistry changes. We focus on intact polar lipids in a phytoplankton community exposed to diverse stressors in a mesocosm experiment. The observed remodeling indicates acyl chain recycling for energy storage in intact polar lipids during stress, reallocating resources based on varying growth conditions. This understanding is essential to grasp the system's impact on cellular pools.
Ingeborg Bussmann, Eric P. Achterberg, Holger Brix, Nicolas Brüggemann, Götz Flöser, Claudia Schütze, and Philipp Fischer
Biogeosciences, 21, 3819–3838, https://doi.org/10.5194/bg-21-3819-2024, https://doi.org/10.5194/bg-21-3819-2024, 2024
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Methane (CH4) is an important greenhouse gas and contributes to climate warming. However, the input of CH4 from coastal areas to the atmosphere is not well defined. Dissolved and atmospheric CH4 was determined at high spatial resolution in or above the North Sea. The atmospheric CH4 concentration was mainly influenced by wind direction. With our detailed study on the spatial distribution of CH4 fluxes we were able to provide a detailed and more realistic estimation of coastal CH4 fluxes.
Lennart Thomas Bach, Aaron James Ferderer, Julie LaRoche, and Kai Georg Schulz
Biogeosciences, 21, 3665–3676, https://doi.org/10.5194/bg-21-3665-2024, https://doi.org/10.5194/bg-21-3665-2024, 2024
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Ocean alkalinity enhancement (OAE) is an emerging marine CO2 removal method, but its environmental effects are insufficiently understood. The OAE Pelagic Impact Intercomparison Project (OAEPIIP) provides funding for a standardized and globally replicated microcosm experiment to study the effects of OAE on plankton communities. Here, we provide a detailed manual for the OAEPIIP experiment. We expect OAEPIIP to help build scientific consensus on the effects of OAE on plankton.
Charly A. Moras, Tyler Cyronak, Lennart T. Bach, Renaud Joannes-Boyau, and Kai G. Schulz
Biogeosciences, 21, 3463–3475, https://doi.org/10.5194/bg-21-3463-2024, https://doi.org/10.5194/bg-21-3463-2024, 2024
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We investigate the effects of mineral grain size and seawater salinity on magnesium hydroxide dissolution and calcium carbonate precipitation kinetics for ocean alkalinity enhancement. Salinity did not affect the dissolution, but calcium carbonate formed earlier at lower salinities due to the lower magnesium and dissolved organic carbon concentrations. Smaller grain sizes dissolved faster but calcium carbonate precipitated earlier, suggesting that medium grain sizes are optimal for kinetics.
Jakob Rønning, Zarah J. Kofoed, Mats Jacobsen, and Carolin R. Löscher
EGUsphere, https://doi.org/10.5194/egusphere-2023-2884, https://doi.org/10.5194/egusphere-2023-2884, 2024
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In our study, we assessed the impact of olivine on marine primary producers of ocean-based solutions. The experiments revealed no negative effects on carbon fixation rates. Additions of the alkaline minerals did not establish growth inhibition; instead, they showed slight growth increases with species-specific responses. Ni exposure from olivine did not inhibit growth. However, limitations include the absence of responses in natural settings.
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, Joaquín Ortiz, Stephen D. Archer, Andrea Ludwig, and Ulf Riebesell
Biogeosciences, 21, 2859–2876, https://doi.org/10.5194/bg-21-2859-2024, https://doi.org/10.5194/bg-21-2859-2024, 2024
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Our planet is facing a climate crisis. Scientists are working on innovative solutions that will aid in capturing the hard to abate emissions before it is too late. Exciting research reveals that ocean alkalinity enhancement, a key climate change mitigation strategy, does not harm phytoplankton, the cornerstone of marine ecosystems. Through meticulous study, we may have uncovered a positive relationship: up to a specific limit, enhancing ocean alkalinity boosts photosynthesis by certain species.
Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, and Lennart T. Bach
Biogeosciences, 21, 2777–2794, https://doi.org/10.5194/bg-21-2777-2024, https://doi.org/10.5194/bg-21-2777-2024, 2024
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Ocean alkalinity enhancement (OAE) is a promising method of atmospheric carbon removal; however, its ecological impacts remain largely unknown. We assessed the effects of simulated silicate- and calcium-based mineral OAE on diatom silicification. We found that increased silicate concentrations from silicate-based OAE increased diatom silicification. In contrast, the enhancement of alkalinity had no effect on community silicification and minimal effects on the silicification of different genera.
David González-Santana, María Segovia, Melchor González-Dávila, Librada Ramírez, Aridane G. González, Leonardo J. Pozzo-Pirotta, Veronica Arnone, Victor Vázquez, Ulf Riebesell, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 2705–2715, https://doi.org/10.5194/bg-21-2705-2024, https://doi.org/10.5194/bg-21-2705-2024, 2024
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In a recent experiment off the coast of Gran Canaria (Spain), scientists explored a method called ocean alkalinization enhancement (OAE), where carbonate minerals were added to seawater. This process changed the levels of certain ions in the water, affecting its pH and buffering capacity. The researchers were particularly interested in how this could impact the levels of essential trace metals in the water.
Jiaying A. Guo, Robert F. Strzepek, Kerrie M. Swadling, Ashley T. Townsend, and Lennart T. Bach
Biogeosciences, 21, 2335–2354, https://doi.org/10.5194/bg-21-2335-2024, https://doi.org/10.5194/bg-21-2335-2024, 2024
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Ocean alkalinity enhancement aims to increase atmospheric CO2 sequestration by adding alkaline materials to the ocean. We assessed the environmental effects of olivine and steel slag powder on coastal plankton. Overall, slag is more efficient than olivine in releasing total alkalinity and, thus, in its ability to sequester CO2. Slag also had less environmental effect on the enclosed plankton communities when considering its higher CO2 removal potential based on this 3-week experiment.
Christian Lønborg, Cátia Carreira, Gwenaël Abril, Susana Agustí, Valentina Amaral, Agneta Andersson, Javier Arístegui, Punyasloke Bhadury, Mariana B. Bif, Alberto V. Borges, Steven Bouillon, Maria Ll. Calleja, Luiz C. Cotovicz Jr., Stefano Cozzi, Maryló Doval, Carlos M. Duarte, Bradley Eyre, Cédric G. Fichot, E. Elena García-Martín, Alexandra Garzon-Garcia, Michele Giani, Rafael Gonçalves-Araujo, Renee Gruber, Dennis A. Hansell, Fuminori Hashihama, Ding He, Johnna M. Holding, William R. Hunter, J. Severino P. Ibánhez, Valeria Ibello, Shan Jiang, Guebuem Kim, Katja Klun, Piotr Kowalczuk, Atsushi Kubo, Choon-Weng Lee, Cláudia B. Lopes, Federica Maggioni, Paolo Magni, Celia Marrase, Patrick Martin, S. Leigh McCallister, Roisin McCallum, Patricia M. Medeiros, Xosé Anxelu G. Morán, Frank E. Muller-Karger, Allison Myers-Pigg, Marit Norli, Joanne M. Oakes, Helena Osterholz, Hyekyung Park, Maria Lund Paulsen, Judith A. Rosentreter, Jeff D. Ross, Digna Rueda-Roa, Chiara Santinelli, Yuan Shen, Eva Teira, Tinkara Tinta, Guenther Uher, Masahide Wakita, Nicholas Ward, Kenta Watanabe, Yu Xin, Youhei Yamashita, Liyang Yang, Jacob Yeo, Huamao Yuan, Qiang Zheng, and Xosé Antón Álvarez-Salgado
Earth Syst. Sci. Data, 16, 1107–1119, https://doi.org/10.5194/essd-16-1107-2024, https://doi.org/10.5194/essd-16-1107-2024, 2024
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In this paper, we present the first edition of a global database compiling previously published and unpublished measurements of dissolved organic matter (DOM) collected in coastal waters (CoastDOM v1). Overall, the CoastDOM v1 dataset will be useful to identify global spatial and temporal patterns and to facilitate reuse in studies aimed at better characterizing local biogeochemical processes and identifying a baseline for modelling future changes in coastal waters.
Xiaoke Xin, Giulia Faucher, and Ulf Riebesell
Biogeosciences, 21, 761–772, https://doi.org/10.5194/bg-21-761-2024, https://doi.org/10.5194/bg-21-761-2024, 2024
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Ocean alkalinity enhancement (OAE) is a promising approach to remove CO2 by accelerating natural rock weathering. However, some of the alkaline substances contain trace metals which could be toxic to marine life. By exposing three representative phytoplankton species to Ni released from alkaline materials, we observed varying responses of phytoplankton to nickel concentrations, suggesting caution should be taken and toxic thresholds should be avoided in OAE with Ni-rich materials.
Lennart Thomas Bach
Biogeosciences, 21, 261–277, https://doi.org/10.5194/bg-21-261-2024, https://doi.org/10.5194/bg-21-261-2024, 2024
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Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.
Matthew D. Eisaman, Sonja Geilert, Phil Renforth, Laura Bastianini, James Campbell, Andrew W. Dale, Spyros Foteinis, Patricia Grasse, Olivia Hawrot, Carolin R. Löscher, Greg H. Rau, and Jakob Rønning
State Planet, 2-oae2023, 3, https://doi.org/10.5194/sp-2-oae2023-3-2023, https://doi.org/10.5194/sp-2-oae2023-3-2023, 2023
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Ocean-alkalinity-enhancement technologies refer to various methods and approaches aimed at increasing the alkalinity of seawater. This chapter explores technologies for increasing ocean alkalinity, including electrochemical-based approaches, ocean liming, accelerated weathering of limestone, hydrated carbonate addition, and coastal enhanced weathering, and suggests best practices in research and development.
David T. Ho, Laurent Bopp, Jaime B. Palter, Matthew C. Long, Philip W. Boyd, Griet Neukermans, and Lennart T. Bach
State Planet, 2-oae2023, 12, https://doi.org/10.5194/sp-2-oae2023-12-2023, https://doi.org/10.5194/sp-2-oae2023-12-2023, 2023
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Monitoring, reporting, and verification (MRV) refers to the multistep process to quantify the amount of carbon dioxide removed by a carbon dioxide removal (CDR) activity. Here, we make recommendations for MRV for Ocean Alkalinity Enhancement (OAE) research, arguing that it has an obligation for comprehensiveness, reproducibility, and transparency, as it may become the foundation for assessing large-scale deployment. Both observations and numerical simulations will be needed for MRV.
Tyler Cyronak, Rebecca Albright, and Lennart T. Bach
State Planet, 2-oae2023, 7, https://doi.org/10.5194/sp-2-oae2023-7-2023, https://doi.org/10.5194/sp-2-oae2023-7-2023, 2023
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Ocean alkalinity enhancement (OAE) is a marine carbon dioxide removal (CDR) approach. Publicly funded research projects have begun, and philanthropic funding and start-ups are collectively pushing the field forward. This rapid progress in research activities has created an urgent need to learn if and how OAE can work at scale. This chapter of the Guide to Best Practices in Ocean Alkalinity Enhancement Research focuses on field experiments.
Ulf Riebesell, Daniela Basso, Sonja Geilert, Andrew W. Dale, and Matthias Kreuzburg
State Planet, 2-oae2023, 6, https://doi.org/10.5194/sp-2-oae2023-6-2023, https://doi.org/10.5194/sp-2-oae2023-6-2023, 2023
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Mesocosm experiments represent a highly valuable tool in determining the safe operating space of ocean alkalinity enhancement (OAE) applications. By combining realism and biological complexity with controllability and replication, they provide an ideal OAE test bed and a critical stepping stone towards field applications. Mesocosm approaches can also be helpful in testing the efficacy, efficiency and permanence of OAE applications.
Kai G. Schulz, Lennart T. Bach, and Andrew G. Dickson
State Planet, 2-oae2023, 2, https://doi.org/10.5194/sp-2-oae2023-2-2023, https://doi.org/10.5194/sp-2-oae2023-2-2023, 2023
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Ocean alkalinity enhancement is a promising approach for long-term anthropogenic carbon dioxide sequestration, required to avoid catastrophic climate change. In this chapter we describe its impacts on seawater carbonate chemistry speciation and highlight pitfalls that need to be avoided during sampling, storage, measurements, and calculations.
Andreas Oschlies, Lennart T. Bach, Rosalind E. M. Rickaby, Terre Satterfield, Romany Webb, and Jean-Pierre Gattuso
State Planet, 2-oae2023, 1, https://doi.org/10.5194/sp-2-oae2023-1-2023, https://doi.org/10.5194/sp-2-oae2023-1-2023, 2023
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Reaching promised climate targets will require the deployment of carbon dioxide removal (CDR). Marine CDR options receive more and more interest. Based on idealized theoretical studies, ocean alkalinity enhancement (OAE) appears as a promising marine CDR method. We provide an overview on the current situation of developing OAE as a marine CDR method and describe the history that has led to the creation of the OAE research best practice guide.
Zhibo Shao, Yangchun Xu, Hua Wang, Weicheng Luo, Lice Wang, Yuhong Huang, Nona Sheila R. Agawin, Ayaz Ahmed, Mar Benavides, Mikkel Bentzon-Tilia, Ilana Berman-Frank, Hugo Berthelot, Isabelle C. Biegala, Mariana B. Bif, Antonio Bode, Sophie Bonnet, Deborah A. Bronk, Mark V. Brown, Lisa Campbell, Douglas G. Capone, Edward J. Carpenter, Nicolas Cassar, Bonnie X. Chang, Dreux Chappell, Yuh-ling Lee Chen, Matthew J. Church, Francisco M. Cornejo-Castillo, Amália Maria Sacilotto Detoni, Scott C. Doney, Cecile Dupouy, Marta Estrada, Camila Fernandez, Bieito Fernández-Castro, Debany Fonseca-Batista, Rachel A. Foster, Ken Furuya, Nicole Garcia, Kanji Goto, Jesús Gago, Mary R. Gradoville, M. Robert Hamersley, Britt A. Henke, Cora Hörstmann, Amal Jayakumar, Zhibing Jiang, Shuh-Ji Kao, David M. Karl, Leila R. Kittu, Angela N. Knapp, Sanjeev Kumar, Julie LaRoche, Hongbin Liu, Jiaxing Liu, Caroline Lory, Carolin R. Löscher, Emilio Marañón, Lauren F. Messer, Matthew M. Mills, Wiebke Mohr, Pia H. Moisander, Claire Mahaffey, Robert Moore, Beatriz Mouriño-Carballido, Margaret R. Mulholland, Shin-ichiro Nakaoka, Joseph A. Needoba, Eric J. Raes, Eyal Rahav, Teodoro Ramírez-Cárdenas, Christian Furbo Reeder, Lasse Riemann, Virginie Riou, Julie C. Robidart, Vedula V. S. S. Sarma, Takuya Sato, Himanshu Saxena, Corday Selden, Justin R. Seymour, Dalin Shi, Takuhei Shiozaki, Arvind Singh, Rachel E. Sipler, Jun Sun, Koji Suzuki, Kazutaka Takahashi, Yehui Tan, Weiyi Tang, Jean-Éric Tremblay, Kendra Turk-Kubo, Zuozhu Wen, Angelicque E. White, Samuel T. Wilson, Takashi Yoshida, Jonathan P. Zehr, Run Zhang, Yao Zhang, and Ya-Wei Luo
Earth Syst. Sci. Data, 15, 3673–3709, https://doi.org/10.5194/essd-15-3673-2023, https://doi.org/10.5194/essd-15-3673-2023, 2023
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N2 fixation by marine diazotrophs is an important bioavailable N source to the global ocean. This updated global oceanic diazotroph database increases the number of in situ measurements of N2 fixation rates, diazotrophic cell abundances, and nifH gene copy abundances by 184 %, 86 %, and 809 %, respectively. Using the updated database, the global marine N2 fixation rate is estimated at 223 ± 30 Tg N yr−1, which triplicates that using the original database.
Moritz Baumann, Allanah Joy Paul, Jan Taucher, Lennart Thomas Bach, Silvan Goldenberg, Paul Stange, Fabrizio Minutolo, and Ulf Riebesell
Biogeosciences, 20, 2595–2612, https://doi.org/10.5194/bg-20-2595-2023, https://doi.org/10.5194/bg-20-2595-2023, 2023
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The sinking velocity of marine particles affects how much atmospheric CO2 is stored inside our oceans. We measured particle sinking velocities in the Peruvian upwelling system and assessed their physical and biochemical drivers. We found that sinking velocity was mainly influenced by particle size and porosity, while ballasting minerals played only a minor role. Our findings help us to better understand the particle sinking dynamics in this highly productive marine system.
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
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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.
Markus A. Min, David M. Needham, Sebastian Sudek, Nathan Kobun Truelove, Kathleen J. Pitz, Gabriela M. Chavez, Camille Poirier, Bente Gardeler, Elisabeth von der Esch, Andrea Ludwig, Ulf Riebesell, Alexandra Z. Worden, and Francisco P. Chavez
Biogeosciences, 20, 1277–1298, https://doi.org/10.5194/bg-20-1277-2023, https://doi.org/10.5194/bg-20-1277-2023, 2023
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Emerging molecular methods provide new ways of understanding how marine communities respond to changes in ocean conditions. Here, environmental DNA was used to track the temporal evolution of biological communities in the Peruvian coastal upwelling system and in an adjacent enclosure where upwelling was simulated. We found that the two communities quickly diverged, with the open ocean being one found during upwelling and the enclosure evolving to one found under stratified conditions.
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
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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.
Jens Hartmann, Niels Suitner, Carl Lim, Julieta Schneider, Laura Marín-Samper, Javier Arístegui, Phil Renforth, Jan Taucher, and Ulf Riebesell
Biogeosciences, 20, 781–802, https://doi.org/10.5194/bg-20-781-2023, https://doi.org/10.5194/bg-20-781-2023, 2023
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CO2 can be stored in the ocean via increasing alkalinity of ocean water. Alkalinity can be created via dissolution of alkaline materials, like limestone or soda. Presented research studies boundaries for increasing alkalinity in seawater. The best way to increase alkalinity was found using an equilibrated solution, for example as produced from reactors. Adding particles for dissolution into seawater on the other hand produces the risk of losing alkalinity and degassing of CO2 to the atmosphere.
André Valente, Shubha Sathyendranath, Vanda Brotas, Steve Groom, Michael Grant, Thomas Jackson, Andrei Chuprin, Malcolm Taberner, Ruth Airs, David Antoine, Robert Arnone, William M. Balch, Kathryn Barker, Ray Barlow, Simon Bélanger, Jean-François Berthon, Şükrü Beşiktepe, Yngve Borsheim, Astrid Bracher, Vittorio Brando, Robert J. W. Brewin, Elisabetta Canuti, Francisco P. Chavez, Andrés Cianca, Hervé Claustre, Lesley Clementson, Richard Crout, Afonso Ferreira, Scott Freeman, Robert Frouin, Carlos García-Soto, Stuart W. Gibb, Ralf Goericke, Richard Gould, Nathalie Guillocheau, Stanford B. Hooker, Chuamin Hu, Mati Kahru, Milton Kampel, Holger Klein, Susanne Kratzer, Raphael Kudela, Jesus Ledesma, Steven Lohrenz, Hubert Loisel, Antonio Mannino, Victor Martinez-Vicente, Patricia Matrai, David McKee, Brian G. Mitchell, Tiffany Moisan, Enrique Montes, Frank Muller-Karger, Aimee Neeley, Michael Novak, Leonie O'Dowd, Michael Ondrusek, Trevor Platt, Alex J. Poulton, Michel Repecaud, Rüdiger Röttgers, Thomas Schroeder, Timothy Smyth, Denise Smythe-Wright, Heidi M. Sosik, Crystal Thomas, Rob Thomas, Gavin Tilstone, Andreia Tracana, Michael Twardowski, Vincenzo Vellucci, Kenneth Voss, Jeremy Werdell, Marcel Wernand, Bozena Wojtasiewicz, Simon Wright, and Giuseppe Zibordi
Earth Syst. Sci. Data, 14, 5737–5770, https://doi.org/10.5194/essd-14-5737-2022, https://doi.org/10.5194/essd-14-5737-2022, 2022
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A compiled set of in situ data is vital to evaluate the quality of ocean-colour satellite data records. Here we describe the global compilation of bio-optical in situ data (spanning from 1997 to 2021) used for the validation of the ocean-colour products from the ESA Ocean Colour Climate Change Initiative (OC-CCI). The compilation merges and harmonizes several in situ data sources into a simple format that could be used directly for the evaluation of satellite-derived ocean-colour data.
Allanah Joy Paul, Lennart Thomas Bach, Javier Arístegui, Elisabeth von der Esch, Nauzet Hernández-Hernández, Jonna Piiparinen, Laura Ramajo, Kristian Spilling, and Ulf Riebesell
Biogeosciences, 19, 5911–5926, https://doi.org/10.5194/bg-19-5911-2022, https://doi.org/10.5194/bg-19-5911-2022, 2022
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We investigated how different deep water chemistry and biology modulate the response of surface phytoplankton communities to upwelling in the Peruvian coastal zone. Our results show that the most influential drivers were the ratio of inorganic nutrients (N : P) and the microbial community present in upwelling source water. These led to unexpected and variable development in the phytoplankton assemblage that could not be predicted by the amount of inorganic nutrients alone.
Aaron Ferderer, Zanna Chase, Fraser Kennedy, Kai G. Schulz, and Lennart T. Bach
Biogeosciences, 19, 5375–5399, https://doi.org/10.5194/bg-19-5375-2022, https://doi.org/10.5194/bg-19-5375-2022, 2022
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Ocean alkalinity enhancement has the capacity to remove vast quantities of carbon from the atmosphere, but its effect on marine ecosystems is largely unknown. We assessed the effect of increased alkalinity on a coastal phytoplankton community when seawater was equilibrated and not equilibrated with atmospheric CO2. We found that the phytoplankton community was moderately affected by increased alkalinity and equilibration with atmospheric CO2 had little influence on this effect.
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
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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.
Charly A. Moras, Lennart T. Bach, Tyler Cyronak, Renaud Joannes-Boyau, and Kai G. Schulz
Biogeosciences, 19, 3537–3557, https://doi.org/10.5194/bg-19-3537-2022, https://doi.org/10.5194/bg-19-3537-2022, 2022
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This research presents the first laboratory results of quick and hydrated lime dissolution in natural seawater. These two minerals are of great interest for ocean alkalinity enhancement, a strategy aiming to decrease atmospheric CO2 concentrations. Following the dissolution of these minerals, we identified several hurdles and presented ways to avoid them or completely negate them. Finally, we proceeded to various simulations in today’s oceans to implement the strategy at its highest potential.
Christian Furbo Reeder, Ina Stoltenberg, Jamileh Javidpour, and Carolin Regina Löscher
Ocean Sci., 18, 401–417, https://doi.org/10.5194/os-18-401-2022, https://doi.org/10.5194/os-18-401-2022, 2022
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The Baltic Sea is predicted to freshen in the future. To explore the effect of decreasing salinity on N2 fixers, we followed the natural salinity gradient in the Baltic Sea from the Kiel Fjord to the Gotland Basin and identified an N2 fixer community dominated by Nodularia and UCYN-A. A salinity threshold was identified at a salinity of 10, with Nodularia dominating at low and UCYN-A dominating at higher salinity, suggesting a future expansion of Nodularia N2 fixers and a retraction of UCYN-A.
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
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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.
Carolin R. Löscher
Biogeosciences, 18, 4953–4963, https://doi.org/10.5194/bg-18-4953-2021, https://doi.org/10.5194/bg-18-4953-2021, 2021
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The Bay of Bengal (BoB) is classically seen as an ocean region with low primary production, which has been predicted to decrease even further. Here, the importance of such a trend is used to explore what could happen to the BoB's low-oxygen core waters if primary production decreases. Lower biological production leads to less oxygen loss in deeper waters by respiration; thus it could be that oxygen will not further decrease and the BoB will not become anoxic, different to other low-oxygen areas.
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
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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
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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.
Nadia Burgoa, Francisco Machín, Ángel Rodríguez-Santana, Ángeles Marrero-Díaz, Xosé Antón Álvarez-Salgado, Bieito Fernández-Castro, María Dolores Gelado-Caballero, and Javier Arístegui
Ocean Sci., 17, 769–788, https://doi.org/10.5194/os-17-769-2021, https://doi.org/10.5194/os-17-769-2021, 2021
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The circulation patterns in the confluence of the North Atlantic subtropical and tropical gyres delimited by the Cape Verde Front were examined during a field cruise in summer 2017. The collected hydrographic data, O2 and inorganic nutrients along the perimeter of a closed box embracing the Cape Verde Frontal Zone allowed for the independent estimation of the transport of these properties.
Siqi Wu, Moge Du, Xianhui Sean Wan, Corday Selden, Mar Benavides, Sophie Bonnet, Robert Hamersley, Carolin R. Löscher, Margaret R. Mulholland, Xiuli Yan, and Shuh-Ji Kao
Biogeosciences Discuss., https://doi.org/10.5194/bg-2021-104, https://doi.org/10.5194/bg-2021-104, 2021
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Nitrogen (N2) fixation is one of the most important nutrient sources to the ocean. Here, we report N2 fixation in the deep, dark ocean in the South China Sea via a highly sensitive new method and elaborate controls, showing the overlooked importance of N2 fixation in the deep ocean. By global data compilation, we also provide an easy measured basic parameter to estimate deep N2 fixation. Our study may help to expand the area limit of N2 fixation studies and better constrain global N2 fixation.
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
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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.
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
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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.
Michelle N. Simone, Kai G. Schulz, Joanne M. Oakes, and Bradley D. Eyre
Biogeosciences, 18, 1823–1838, https://doi.org/10.5194/bg-18-1823-2021, https://doi.org/10.5194/bg-18-1823-2021, 2021
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Estuaries are responsible for a large contribution of dissolved organic carbon (DOC) to the global C cycle, but it is unknown how this will change in the future. DOC fluxes from unvegetated sediments were investigated ex situ subject to conditions of warming and ocean acidification. The future climate shifted sediment fluxes from a slight DOC source to a significant sink, with global coastal DOC export decreasing by 80 %. This has global implications for C cycling and long-term C storage.
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
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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
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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
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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.
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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.
The eastern boundary upwelling system off Peru is among Earth's most productive ocean...
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