Articles | Volume 22, issue 14
https://doi.org/10.5194/bg-22-3485-2025
© Author(s) 2025. 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-22-3485-2025
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| Highlight paper
| 
18 Jul 2025
Research article | Highlight paper |
| 18 Jul 2025
| 18 Jul 2025
Marine snow morphology drives sinking and attenuation in the ocean interior
Yawouvi Dodji Soviadan
CORRESPONDING AUTHOR
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, UMR 7093 LOV, Villefranche-sur-Mer, France
Université de Lomé, Lomé, Togo
MARBEC, IRD, IFREMER, CNRS, Université de Montpellier, 87 Avenue Jean Monnet, 34200 Sète, France
Miriam Beck
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, UMR 7093 LOV, Villefranche-sur-Mer, France
FRB-CESAB, Montpellier, France
Joelle Habib
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, UMR 7093 LOV, Villefranche-sur-Mer, France
Alberto Baudena
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, UMR 7093 LOV, Villefranche-sur-Mer, France
Consiglio Nazionale Delle Ricerche-Istituto di Scienze Marine (CNR-ISMAR), Lerici (SP), Italy
Laetitia Drago
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, UMR 7093 LOV, Villefranche-sur-Mer, France
Sorbonne Université, UMR 7159 CNRS-IRD-MNHN, LOCEAN-IPSL, Paris, France
Alexandre Accardo
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, UMR 7093 LOV, Villefranche-sur-Mer, France
Remi Laxenaire
Laboratoire de l'Atmosphère et des Cyclones, LACy, UMR 8105, CNRS, Université de La Réunion, Météo-France, Saint-Denis de La Réunion, France
Center for Ocean-Atmospheric Prediction Studies, Florida State University, Tallahassee, FL, USA
Sabrina Speich
Laboratoire de Météorologie Dynamique – IPSL, ENS – PSL, Paris, France
Peter Brandt
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Faculty of Mathematics and Natural Sciences, Kiel University, Kiel, Germany
Rainer Kiko
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, UMR 7093 LOV, Villefranche-sur-Mer, France
GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
Faculty of Mathematics and Natural Sciences, Kiel University, Kiel, Germany
Sorbonne Université, CNRS, Laboratoire d'Océanographie de Villefranche, UMR 7093 LOV, Villefranche-sur-Mer, France
Institut Universitaire de France, Paris, France
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EGUsphere, https://doi.org/10.5194/egusphere-2026-6032, https://doi.org/10.5194/egusphere-2026-6032, 2026
This preprint is open for discussion and under review for Ocean Science (OS).
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Ariadna C. Nocera, Lars Stemmann, Marcel Babin, Tristan Biard, Julie Coustenoble, François Carlotti, Laurent Coppola, Lucas Courchet, Laetitia Drago, Amanda Elineau, Lionel Guidi, Helena Hauss, Laëtitia Jalabert, Lee Karp-Boss, Rainer Kiko, Manon Laget, Fabien Lombard, Andrew McDonnell, Camille Merland, Solène Motreuil, Thelma Panaïotis, Marc Picheral, Andreas Rogge, Anya Waite, and Jean-Olivier Irisson
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Keun-Ok Lee, Soline Bielli, Clément Soufflet, Rémi Laxenaire, and Kevin Hoarau
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Dante C. Napolitano, Jonathan Gula, Solange Coadou-Chaventon, Sabrina Speich, Cesar B. Rocha, James C. McWilliams, Dongxiao Zhang, and Xavier Carton
Ocean Sci., 22, 2425–2447, https://doi.org/10.5194/os-22-2425-2026, https://doi.org/10.5194/os-22-2425-2026, 2026
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Alexandra Andrae, Peter Brandt, Franz Philip Tuchen, Rebecca Hummels, and Joke F. Lübbecke
EGUsphere, https://doi.org/10.5194/egusphere-2026-4390, https://doi.org/10.5194/egusphere-2026-4390, 2026
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Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2026-343, https://doi.org/10.5194/essd-2026-343, 2026
Revised manuscript accepted for ESSD
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BOWTIE (Beobachtung von Ozean und Wolken - Das Trans ITCZ Experiment) was an observational campaign occurring in summer 2024, which intensively took measurements from the upper ocean to the upper troposphere in the wettest region of the tropical Atlantic. Here, we provide an overview of the measurements and instrumentation, including remote sensing and conventional, which targeted small-scale processes under different weather regimes, from calm doldrums to gusty, precipitating events.
Rémi Laxenaire, Eric P. Chassignet, Xiaobiao Xu, Alan J. Wallcraft, Luna Hiron, Brian K. Arbic, Maarten C. Buijsman, Miguel Solano, and Shane Elipot
Geosci. Model Dev., 19, 5571–5599, https://doi.org/10.5194/gmd-19-5571-2026, https://doi.org/10.5194/gmd-19-5571-2026, 2026
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Surface kinetic energy reflects the distribution of ocean circulation across temporal and spatial scales, shaping energy transfer and mixing in the upper ocean. In a series of North and Equatorial Atlantic numerical simulations, we show that the surface kinetic energy is sensitive to the model's choices in grid and seafloor resolution and to the tides and wind variability, offering guidance for the configuration of future ocean simulations.
Anna Christina Hans, Rebecca Hummels, Peter Brandt, Franziska U. Schwarzkopf, and Stephan Juricke
EGUsphere, https://doi.org/10.5194/egusphere-2026-2983, https://doi.org/10.5194/egusphere-2026-2983, 2026
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We mimic an observational array at 11°S in an ocean model to assess its capability to compute the temporal variability of the Atlantic Meridional Overturning Circulation. The current approaches based on bottom pressure sensors and measurements of the boundary currents explain large parts of the transport variability. Improvements can be achieved by also considering temperature and salinity data, while the potential of self-calibrating pressure sensors and inverted echo sounders is limited.
Joelle Habib, Caroline Ulses, Claude Estournel, Milad Fakhri, Patrick Marsaleix, Thierry Moutin, Dominique Lefevre, Mireille Pujo-Pay, Marine Fourrier, Laurent Coppola, Cathy Wimart-Rousseau, and Pascal Conan
Biogeosciences, 23, 2939–2958, https://doi.org/10.5194/bg-23-2939-2026, https://doi.org/10.5194/bg-23-2939-2026, 2026
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The Levantine Basin in the eastern Mediterranean Sea is one of the most nutrient-poor marine regions on Earth. Using a detailed model and observations, we studied how oxygen changes from 2013 to 2020. We found that winter cooling draws oxygen into the sea and moves it to deeper waters, while warmer months release some back. Overall, the basin absorbs more oxygen than it releases, and winter heat loss and circulation patterns strongly control how oxygen is stored and transported.
Nasrollah Moradi, Lili Hufnagel, Simon Ramondenc, Clara M. Flintrop, Rainer Kiko, Tim Fischer, Helena Hauss, Arne Körtzinger, Gerhard Fischer, and Morten H. Iversen
Biogeosciences, 23, 2179–2203, https://doi.org/10.5194/bg-23-2179-2026, https://doi.org/10.5194/bg-23-2179-2026, 2026
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Audrey Minière, Karina von Schuckmann, and Sabrina Speich
Earth Syst. Sci. Data Discuss., https://doi.org/10.5194/essd-2026-106, https://doi.org/10.5194/essd-2026-106, 2026
Preprint under review for ESSD
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This study assesses the sensitivity of global ocean heat content estimates to key methodological choices. Global trends are robust across methodological configurations. Most of the spread comes from the choice of temperature dataset, while other methodological impacts remain small. Our results show that both research and operational indicators consistently track global ocean warming, supporting their reliability and traceability for climate monitoring and Earth energy budget assessments.
Pablo Fernández, Sabrina Speich, Guillaume Lapeyre, Claudia Pasquero, Carlos Conejero, Lionel Renault, and Fabien Desbiolles
Ocean Sci., 22, 699–725, https://doi.org/10.5194/os-22-699-2026, https://doi.org/10.5194/os-22-699-2026, 2026
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We use a high-resolution ocean-atmosphere coupled simulation to assess the effects of fine-scale sea surface temperature, surface currents, and ocean vertical stratification on the spatial variability of latent heat flux in the Northwest Tropical Atlantic. The results show significant impacts from these three variables in latent heat flux. They stress the need to account for fine-scale ocean processes in the coarser global coupled models even in relatively quiescent regions like the tropics.
Florian Schütte, Johannes Hahn, Ivy Frenger, Arne Bendinger, Ahmad Fehmi Dilmahamod, Marco Schulz, and Peter Brandt
Ocean Sci., 22, 119–143, https://doi.org/10.5194/os-22-119-2026, https://doi.org/10.5194/os-22-119-2026, 2026
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We found extreme drops in oxygen levels in the tropical Atlantic linked to surprisingly long-lived, small subsurface eddies. These eddies are hidden beneath the surface (undetectable by satellites) and are unusually stable, even in the highly dynamic ocean near the equator. Using long-term measurements and computer models, we show that these features can strongly influence oxygen supply and potentially impact marine ecosystems.
Joelle Habib, Lars Stemmann, Alexandre Accardo, Alberto Baudena, Franz Philip Tuchen, Peter Brandt, and Rainer Kiko
Biogeosciences, 22, 7985–8003, https://doi.org/10.5194/bg-22-7985-2025, https://doi.org/10.5194/bg-22-7985-2025, 2025
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This study investigates how carbon moves from the ocean surface to the depths in the equatorial Atlantic, contributing to long-term carbon storage. Using an Argo float equipped with a camera, we captured two periods with major carbon export events. By identifying particle types and their sinking behaviors, we found that smaller, compact particles are key drivers of carbon transport. Our findings underscore the value of using imaging tools on autonomous platforms in tracking carbon sequestration.
Yan Barabinot, Sabrina Speich, and Xavier Carton
Ocean Sci., 21, 2527–2553, https://doi.org/10.5194/os-21-2527-2025, https://doi.org/10.5194/os-21-2527-2025, 2025
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Mesoscale eddies, characterized by rotating currents, are ubiquitous in the ocean. However, their three-dimensional structure remains poorly observed and analyzed, with transport estimates often relying on approximations. To better quantify their shape, we propose a new theoretical framework based on geophysical fluid dynamics and apply it to field observations.
Yan Barabinot, Sabrina Speich, Xavier Carton, Pierre L'Hégaret, Corentin Subirade, Rémi Laxenaire, and Johannes Karstensen
Ocean Sci., 21, 1849–1872, https://doi.org/10.5194/os-21-1849-2025, https://doi.org/10.5194/os-21-1849-2025, 2025
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Mesoscale eddies are rotating oceanic currents key to ocean variability. Off Brazil’s northeast coast, the North Brazil Current generates on average 4.5 eddies per year, which drift towards the West Indies, transporting waters from the Southern Hemisphere. Using data collected at sea by the EUREC4A-OA cruise, this study reveals that deep eddies transport 5 times more water than surface ones, reshaping our understanding of the regional water transport.
Léo C. Aroucha, Joke F. Lübbecke, Peter Brandt, Franziska U. Schwarzkopf, and Arne Biastoch
Ocean Sci., 21, 661–678, https://doi.org/10.5194/os-21-661-2025, https://doi.org/10.5194/os-21-661-2025, 2025
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The west African coastal region sustains highly productive fisheries and marine ecosystems influenced by sea surface temperature. We use oceanic models to show that the freshwater input from land to ocean strengthens a surface northward (southward) coastal current north (south) of the Congo River mouth, promoting a transfer of cooler (warmer) waters to north (south) of the Congo discharge location. We highlight the significant impact of river discharge on ocean temperatures and circulation.
Alexandre Accardo, Rémi Laxenaire, Alberto Baudena, Sabrina Speich, Rainer Kiko, and Lars Stemmann
Biogeosciences, 22, 1183–1201, https://doi.org/10.5194/bg-22-1183-2025, https://doi.org/10.5194/bg-22-1183-2025, 2025
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The open ocean helps mitigate climate change by storing CO2 via the biological carbon pump (BCP), which involves processes like organic carbon production at the surface and transferring it to the deep ocean via various pathways. By deploying an autonomous platform, we found significant marine snow accumulation from the surface to the mesopelagic zone in frontal regions between eddies. We suggest that the coupling of hydrodynamics at eddy edges and biological activity may enhance this process.
Yan Barabinot, Sabrina Speich, and Xavier Carton
Ocean Sci., 21, 151–179, https://doi.org/10.5194/os-21-151-2025, https://doi.org/10.5194/os-21-151-2025, 2025
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Mesoscale eddies are ubiquitous rotating currents in the ocean. Some eddies, called "materially coherent", are able to transport a different water mass from the surrounding water. By analyzing 3D eddy structures sampled during oceanographic cruises, we found that eddies can be nonmaterially coherent, accounting only for their surface properties, but materially coherent considering their properties at depth. Future studies cannot rely solely on satellite data to evaluate heat and salt transport.
Eike E. Köhn, Richard J. Greatbatch, Peter Brandt, and Martin Claus
Ocean Sci., 20, 1281–1290, https://doi.org/10.5194/os-20-1281-2024, https://doi.org/10.5194/os-20-1281-2024, 2024
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The latitudinally alternating zonal jets are a ubiquitous feature of the ocean. We use a simple model to illustrate the potential role of these jets in the formation, maintenance, and multidecadal variability in the oxygen minimum zones, using the eastern tropical North Atlantic oxygen minimum zone as an example.
Mathilde Dugenne, Marco Corrales-Ugalde, Jessica Y. Luo, Rainer Kiko, Todd D. O'Brien, Jean-Olivier Irisson, Fabien Lombard, Lars Stemmann, Charles Stock, Clarissa R. Anderson, Marcel Babin, Nagib Bhairy, Sophie Bonnet, Francois Carlotti, Astrid Cornils, E. Taylor Crockford, Patrick Daniel, Corinne Desnos, Laetitia Drago, Amanda Elineau, Alexis Fischer, Nina Grandrémy, Pierre-Luc Grondin, Lionel Guidi, Cecile Guieu, Helena Hauss, Kendra Hayashi, Jenny A. Huggett, Laetitia Jalabert, Lee Karp-Boss, Kasia M. Kenitz, Raphael M. Kudela, Magali Lescot, Claudie Marec, Andrew McDonnell, Zoe Mériguet, Barbara Niehoff, Margaux Noyon, Thelma Panaïotis, Emily Peacock, Marc Picheral, Emilie Riquier, Collin Roesler, Jean-Baptiste Romagnan, Heidi M. Sosik, Gretchen Spencer, Jan Taucher, Chloé Tilliette, and Marion Vilain
Earth Syst. Sci. Data, 16, 2971–2999, https://doi.org/10.5194/essd-16-2971-2024, https://doi.org/10.5194/essd-16-2971-2024, 2024
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Plankton and particles influence carbon cycling and energy flow in marine ecosystems. We used three types of novel plankton imaging systems to obtain size measurements from a range of plankton and particle sizes and across all major oceans. Data were compiled and cross-calibrated from many thousands of images, showing seasonal and spatial changes in particle size structure in different ocean basins. These datasets form the first release of the Pelagic Size Structure database (PSSdb).
Kristin Burmeister, Franziska U. Schwarzkopf, Willi Rath, Arne Biastoch, Peter Brandt, Joke F. Lübbecke, and Mark Inall
Ocean Sci., 20, 307–339, https://doi.org/10.5194/os-20-307-2024, https://doi.org/10.5194/os-20-307-2024, 2024
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We apply two different forcing products to a high-resolution ocean model to investigate their impact on the simulated upper-current field in the tropical Atlantic. Where possible, we compare the simulated results to long-term observations. We find large discrepancies between the two simulations regarding the wind and current fields. We propose that long-term observations, once they have reached a critical length, need to be used to test the quality of wind-driven simulations.
Jonathan Andrew Baker, Richard Renshaw, Laura Claire Jackson, Clotilde Dubois, Doroteaciro Iovino, Hao Zuo, Renellys C. Perez, Shenfu Dong, Marion Kersalé, Michael Mayer, Johannes Mayer, Sabrina Speich, and Tarron Lamont
State Planet, 1-osr7, 4, https://doi.org/10.5194/sp-1-osr7-4-2023, https://doi.org/10.5194/sp-1-osr7-4-2023, 2023
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We use ocean reanalyses, in which ocean models are combined with observations, to infer past changes in ocean circulation and heat transport in the South Atlantic. Comparing these estimates with other observation-based estimates, we find differences in their trends, variability, and mean heat transport but closer agreement in their mean overturning strength. Ocean reanalyses can help us understand the cause of these differences, which could improve estimates of ocean transports in this region.
Saeed Hariri, Sabrina Speich, Bruno Blanke, and Marina Lévy
Ocean Sci., 19, 1183–1201, https://doi.org/10.5194/os-19-1183-2023, https://doi.org/10.5194/os-19-1183-2023, 2023
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This work presents a series of studies conducted by the authors on the application of the Lagrangian approach for the connectivity analysis between different ocean locations in an idealized open-ocean model. We assess how the connectivity properties of typical oceanic flows are affected by the fine-scale circulation and discuss the challenges facing ocean connectivity estimates related to the spatial resolution. Our results are important to improve the understanding of marine ecosystems.
Joelle Habib, Caroline Ulses, Claude Estournel, Milad Fakhri, Patrick Marsaleix, Mireille Pujo-Pay, Marine Fourrier, Laurent Coppola, Alexandre Mignot, Laurent Mortier, and Pascal Conan
Biogeosciences, 20, 3203–3228, https://doi.org/10.5194/bg-20-3203-2023, https://doi.org/10.5194/bg-20-3203-2023, 2023
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The Rhodes Gyre, eastern Mediterranean Sea, is the main Levantine Intermediate Water formation site. In this study, we use a 3D physical–biogeochemical model to investigate the seasonal and interannual variability of organic carbon dynamics in the gyre. Our results show its autotrophic nature and its high interannual variability, with enhanced primary production, downward exports, and onward exports to the surrounding regions during years marked by intense heat losses and deep mixed layers.
Swantje Bastin, Martin Claus, Richard J. Greatbatch, and Peter Brandt
Ocean Sci., 19, 923–939, https://doi.org/10.5194/os-19-923-2023, https://doi.org/10.5194/os-19-923-2023, 2023
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Equatorial deep jets are ocean currents that flow along the Equator in the deep oceans. They are relevant for oxygen transport and tropical surface climate, but their dynamics are not yet entirely understood. We investigate different factors leading to the jets being broader than theory predicts. Mainly using an ocean model, but corroborating the results with shipboard observations, we show that loss of momentum is the main factor for the broadening but that meandering also contributes.
Peter Brandt, Gaël Alory, Founi Mesmin Awo, Marcus Dengler, Sandrine Djakouré, Rodrigue Anicet Imbol Koungue, Julien Jouanno, Mareike Körner, Marisa Roch, and Mathieu Rouault
Ocean Sci., 19, 581–601, https://doi.org/10.5194/os-19-581-2023, https://doi.org/10.5194/os-19-581-2023, 2023
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Tropical upwelling systems are among the most productive ecosystems globally. The tropical Atlantic upwelling undergoes a strong seasonal cycle that is forced by the wind. Local wind-driven upwelling and remote effects, particularly via the propagation of equatorial and coastal trapped waves, lead to an upward and downward movement of the nitracline. Turbulent mixing results in upward supply of nutrients. Here, we review the different physical processes responsible for biological productivity.
Pierre L'Hégaret, Florian Schütte, Sabrina Speich, Gilles Reverdin, Dariusz B. Baranowski, Rena Czeschel, Tim Fischer, Gregory R. Foltz, Karen J. Heywood, Gerd Krahmann, Rémi Laxenaire, Caroline Le Bihan, Philippe Le Bot, Stéphane Leizour, Callum Rollo, Michael Schlundt, Elizabeth Siddle, Corentin Subirade, Dongxiao Zhang, and Johannes Karstensen
Earth Syst. Sci. Data, 15, 1801–1830, https://doi.org/10.5194/essd-15-1801-2023, https://doi.org/10.5194/essd-15-1801-2023, 2023
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In early 2020, the EUREC4A-OA/ATOMIC experiment took place in the northwestern Tropical Atlantic Ocean, a dynamical region where different water masses interact. Four oceanographic vessels and a fleet of autonomous devices were deployed to study the processes at play and sample the upper ocean, each with its own observing capability. The article first describes the data calibration and validation and second their cross-validation, using a hierarchy of instruments and estimating the uncertainty.
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.
Adriana Bailey, Franziska Aemisegger, Leonie Villiger, Sebastian A. Los, Gilles Reverdin, Estefanía Quiñones Meléndez, Claudia Acquistapace, Dariusz B. Baranowski, Tobias Böck, Sandrine Bony, Tobias Bordsdorff, Derek Coffman, Simon P. de Szoeke, Christopher J. Diekmann, Marina Dütsch, Benjamin Ertl, Joseph Galewsky, Dean Henze, Przemyslaw Makuch, David Noone, Patricia K. Quinn, Michael Rösch, Andreas Schneider, Matthias Schneider, Sabrina Speich, Bjorn Stevens, and Elizabeth J. Thompson
Earth Syst. Sci. Data, 15, 465–495, https://doi.org/10.5194/essd-15-465-2023, https://doi.org/10.5194/essd-15-465-2023, 2023
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One of the novel ways EUREC4A set out to investigate trade wind clouds and their coupling to the large-scale circulation was through an extensive network of isotopic measurements in water vapor, precipitation, and seawater. Samples were taken from the island of Barbados, from aboard two aircraft, and from aboard four ships. This paper describes the full collection of EUREC4A isotopic in situ data and guides readers to complementary remotely sensed water vapor isotope ratios.
Mareike Körner, Peter Brandt, and Marcus Dengler
Ocean Sci., 19, 121–139, https://doi.org/10.5194/os-19-121-2023, https://doi.org/10.5194/os-19-121-2023, 2023
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The coastal waters off Angola host a productive ecosystem. Surface waters at the coast are colder than further offshore. We find that surface heat fluxes warm the coastal region more strongly than the offshore region and cannot explain the differences. The influence of horizontal heat advection is minor on the surface temperature change. In contrast, ocean turbulence data suggest that cooling associated with vertical mixing is an important mechanism to explain the near-coastal cooling.
Rainer Kiko, Marc Picheral, David Antoine, Marcel Babin, Léo Berline, Tristan Biard, Emmanuel Boss, Peter Brandt, Francois Carlotti, Svenja Christiansen, Laurent Coppola, Leandro de la Cruz, Emilie Diamond-Riquier, Xavier Durrieu de Madron, Amanda Elineau, Gabriel Gorsky, Lionel Guidi, Helena Hauss, Jean-Olivier Irisson, Lee Karp-Boss, Johannes Karstensen, Dong-gyun Kim, Rachel M. Lekanoff, Fabien Lombard, Rubens M. Lopes, Claudie Marec, Andrew M. P. McDonnell, Daniela Niemeyer, Margaux Noyon, Stephanie H. O'Daly, Mark D. Ohman, Jessica L. Pretty, Andreas Rogge, Sarah Searson, Masashi Shibata, Yuji Tanaka, Toste Tanhua, Jan Taucher, Emilia Trudnowska, Jessica S. Turner, Anya Waite, and Lars Stemmann
Earth Syst. Sci. Data, 14, 4315–4337, https://doi.org/10.5194/essd-14-4315-2022, https://doi.org/10.5194/essd-14-4315-2022, 2022
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The term
marine particlescomprises detrital aggregates; fecal pellets; bacterioplankton, phytoplankton and zooplankton; and even fish. Here, we present a global dataset that contains 8805 vertical particle size distribution profiles obtained with Underwater Vision Profiler 5 (UVP5) camera systems. These data are valuable to the scientific community, as they can be used to constrain important biogeochemical processes in the ocean, such as the flux of carbon to the deep sea.
Léa Olivier, Jacqueline Boutin, Gilles Reverdin, Nathalie Lefèvre, Peter Landschützer, Sabrina Speich, Johannes Karstensen, Matthieu Labaste, Christophe Noisel, Markus Ritschel, Tobias Steinhoff, and Rik Wanninkhof
Biogeosciences, 19, 2969–2988, https://doi.org/10.5194/bg-19-2969-2022, https://doi.org/10.5194/bg-19-2969-2022, 2022
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We investigate the impact of the interactions between eddies and the Amazon River plume on the CO2 air–sea fluxes to better characterize the ocean carbon sink in winter 2020. The region is a strong CO2 sink, previously underestimated by a factor of 10 due to a lack of data and understanding of the processes responsible for the variability in ocean carbon parameters. The CO2 absorption is mainly driven by freshwater from the Amazon entrained by eddies and by the winter seasonal cooling.
Natalia Belkin, Tamar Guy-Haim, Maxim Rubin-Blum, Ayah Lazar, Guy Sisma-Ventura, Rainer Kiko, Arseniy R. Morov, Tal Ozer, Isaac Gertman, Barak Herut, and Eyal Rahav
Ocean Sci., 18, 693–715, https://doi.org/10.5194/os-18-693-2022, https://doi.org/10.5194/os-18-693-2022, 2022
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We studied how distinct water circulations that elevate (cyclone) or descend (anticyclone) water from the upper ocean affect the biomass, activity and diversity of planktonic microorganisms in the impoverished eastern Mediterranean. We show that cyclonic and anticyclonic eddies differ in their community composition and production. Moreover, the anticyclone may be a potential bio-invasion and dispersal vector, while the cyclone may serve as a thermal refugee for native species.
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Editorial statement
This study is the first to measure marine snow morphologies, sinking speeds, and midwater attenuation in export plumes using a BGC-Argo float equipped with optical and imaging sensors, offering new insights into the effects of morphology on particle sinking. The findings emphasize the need to move beyond size-based models by incorporating morphological properties to improve understanding of particle sinking and enhance flux estimates, with potential applications for monitoring natural and human-induced export events at high spatio-temporal resolution.
This study is the first to measure marine snow morphologies, sinking speeds, and midwater...
Short summary
Key parameters representing the gravity flux in global models are sinking speed and vertical attenuation of exported material. We calculate, for the first time, these parameters in situ in the ocean for six intermittent blooms followed by export events using high-resolution (3 d) time series of 0–1000 m depth profiles from imaging sensors mounted on an Argo float. We show that sinking speed depends not only on size but also on the morphology of the particles, with density being an important property.
Key parameters representing the gravity flux in global models are sinking speed and vertical...
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