Articles | Volume 17, issue 13
https://doi.org/10.5194/bg-17-3343-2020
© 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-17-3343-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
02 Jul 2020
Research article |
| 02 Jul 2020
| 02 Jul 2020
Profiling float observation of thermohaline staircases in the western Mediterranean Sea and impact on nutrient fluxes
Vincent Taillandier
CORRESPONDING AUTHOR
Laboratoire d'Océanographie de
Villefranche, UMR 7093, CNRS, Sorbonne Universités, Villefranche-sur-Mer, France
Louis Prieur
Laboratoire d'Océanographie de
Villefranche, UMR 7093, CNRS, Sorbonne Universités, Villefranche-sur-Mer, France
Fabrizio D'Ortenzio
Laboratoire d'Océanographie de
Villefranche, UMR 7093, CNRS, Sorbonne Universités, Villefranche-sur-Mer, France
Maurizio Ribera d'Alcalà
Department of Integrative Marine Ecology, Stazione Zoologica Anton
Dohrn, Naples, Italy
Istituto per lo Studio degli Impatti Antropici e Sostenibilità in Ambiente Marino, CNR, Rome, Italy
Elvira Pulido-Villena
Mediterranean Institute of Oceanography, UMR 7294, Aix-Marseille Université, CNRS, Université de Toulon, IRD, Marseille, France
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We report on phosphorus dynamics in the surface layer of the Mediterranean Sea. Highly sensitive phosphate measurements revealed vertical gradients above the phosphacline. The relative contribution of diapycnal fluxes to total external supply of phosphate to the mixed layer decreased towards the east, where atmospheric deposition dominated. Taken together, external sources of phosphate contributed little to total supply, which was mainly sustained by enzymatic hydrolysis of organic phosphorus.
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The concentration of chlorophyll is commonly used as an indicator of the abundance of photosynthetic plankton (phytoplankton) in lakes and oceans. Our study investigates why a deep chlorophyll maximum, located near the bottom of the upper, illuminated layer develops in the Mediterranean Sea. We find that the acclimation of cells to low light is the main mechanism involved and that this deep maximum represents also a maximum in the biomass and carbon fixation activity of phytoplankton.
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We show that in the Mediterranean Sea spatial variability in N2 fixation is related to the diazotrophic community composition reflecting different nutrient requirements among species. Nutrient supply by Saharan dust is of great importance to diazotrophs, as shown by the strong stimulation of N2 fixation after a simulated dust event under present and future climate conditions; the magnitude of stimulation depends on the degree of limitation related to the diazotrophic community composition.
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We report on phosphorus dynamics in the surface layer of the Mediterranean Sea. Highly sensitive phosphate measurements revealed vertical gradients above the phosphacline. The relative contribution of diapycnal fluxes to total external supply of phosphate to the mixed layer decreased towards the east, where atmospheric deposition dominated. Taken together, external sources of phosphate contributed little to total supply, which was mainly sustained by enzymatic hydrolysis of organic phosphorus.
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Paolo Lazzari, Stefano Salon, Elena Terzić, Watson W. Gregg, Fabrizio D'Ortenzio, Vincenzo Vellucci, Emanuele Organelli, and David Antoine
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Multispectral optical sensors and models are increasingly adopted to study marine systems. In this work, bio-optical mooring and biogeochemical Argo float optical observations are combined with the Ocean-Atmosphere Spectral Irradiance Model (OASIM) to analyse the variability of sunlight at the sea surface. We show that the model skill in simulating data varies according to the wavelength of light and temporal scale considered and that it is significantly affected by cloud dynamics.
Philippe Massicotte, Rainer M. W. Amon, David Antoine, Philippe Archambault, Sergio Balzano, Simon Bélanger, Ronald Benner, Dominique Boeuf, Annick Bricaud, Flavienne Bruyant, Gwenaëlle Chaillou, Malik Chami, Bruno Charrière, Jing Chen, Hervé Claustre, Pierre Coupel, Nicole Delsaut, David Doxaran, Jens Ehn, Cédric Fichot, Marie-Hélène Forget, Pingqing Fu, Jonathan Gagnon, Nicole Garcia, Beat Gasser, Jean-François Ghiglione, Gaby Gorsky, Michel Gosselin, Priscillia Gourvil, Yves Gratton, Pascal Guillot, Hermann J. Heipieper, Serge Heussner, Stanford B. Hooker, Yannick Huot, Christian Jeanthon, Wade Jeffrey, Fabien Joux, Kimitaka Kawamura, Bruno Lansard, Edouard Leymarie, Heike Link, Connie Lovejoy, Claudie Marec, Dominique Marie, Johannie Martin, Jacobo Martín, Guillaume Massé, Atsushi Matsuoka, Vanessa McKague, Alexandre Mignot, William L. Miller, Juan-Carlos Miquel, Alfonso Mucci, Kaori Ono, Eva Ortega-Retuerta, Christos Panagiotopoulos, Tim Papakyriakou, Marc Picheral, Louis Prieur, Patrick Raimbault, Joséphine Ras, Rick A. Reynolds, André Rochon, Jean-François Rontani, Catherine Schmechtig, Sabine Schmidt, Richard Sempéré, Yuan Shen, Guisheng Song, Dariusz Stramski, Eri Tachibana, Alexandre Thirouard, Imma Tolosa, Jean-Éric Tremblay, Mickael Vaïtilingom, Daniel Vaulot, Frédéric Vaultier, John K. Volkman, Huixiang Xie, Guangming Zheng, and Marcel Babin
Earth Syst. Sci. Data, 13, 1561–1592, https://doi.org/10.5194/essd-13-1561-2021, https://doi.org/10.5194/essd-13-1561-2021, 2021
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The MALINA oceanographic expedition was conducted in the Mackenzie River and the Beaufort Sea systems. The sampling was performed across seven shelf–basin transects to capture the meridional gradient between the estuary and the open ocean. The main goal of this research program was to better understand how processes such as primary production are influencing the fate of organic matter originating from the surrounding terrestrial landscape during its transition toward the Arctic Ocean.
France Van Wambeke, Elvira Pulido, Philippe Catala, Julie Dinasquet, Kahina Djaoudi, Anja Engel, Marc Garel, Sophie Guasco, Barbara Marie, Sandra Nunige, Vincent Taillandier, Birthe Zäncker, and Christian Tamburini
Biogeosciences, 18, 2301–2323, https://doi.org/10.5194/bg-18-2301-2021, https://doi.org/10.5194/bg-18-2301-2021, 2021
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Michaelis–Menten kinetics were determined for alkaline phosphatase, aminopeptidase and β-glucosidase in the Mediterranean Sea. Although the ectoenzymatic-hydrolysis contribution to heterotrophic prokaryotic needs was high in terms of N, it was low in terms of C. This study points out the biases in interpretation of the relative differences in activities among the three tested enzymes in regard to the choice of added concentrations of fluorogenic substrates.
Emilio Marañón, France Van Wambeke, Julia Uitz, Emmanuel S. Boss, Céline Dimier, Julie Dinasquet, Anja Engel, Nils Haëntjens, María Pérez-Lorenzo, Vincent Taillandier, and Birthe Zäncker
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The concentration of chlorophyll is commonly used as an indicator of the abundance of photosynthetic plankton (phytoplankton) in lakes and oceans. Our study investigates why a deep chlorophyll maximum, located near the bottom of the upper, illuminated layer develops in the Mediterranean Sea. We find that the acclimation of cells to low light is the main mechanism involved and that this deep maximum represents also a maximum in the biomass and carbon fixation activity of phytoplankton.
Florian Ricour, Arthur Capet, Fabrizio D'Ortenzio, Bruno Delille, and Marilaure Grégoire
Biogeosciences, 18, 755–774, https://doi.org/10.5194/bg-18-755-2021, https://doi.org/10.5194/bg-18-755-2021, 2021
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This paper addresses the phenology of the deep chlorophyll maximum (DCM) in the Black Sea (BS). We show that the DCM forms in March at a density level set by the winter mixed layer. It maintains this location until June, suggesting an influence of the DCM on light and nutrient profiles rather than mere adaptation to external factors. In summer, the DCM concentrates ~55 % of the chlorophyll in a 10 m layer at ~35 m depth and should be considered a major feature of the BS phytoplankton dynamics.
Elena Terzić, Arnau Miró, Paolo Lazzari, Emanuele Organelli, and Fabrizio D'Ortenzio
Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-473, https://doi.org/10.5194/bg-2020-473, 2021
Preprint withdrawn
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This study integrates numerical simulations (using a multi-spectral optical model) with in-situ measurements of floats and remotely sensed observations from satellites. It aims at improving our current understanding of the impact that different constituents (such as pure water, colored dissolved organic matter, detritus and phytoplankton) have on the in-water light propagation.
Kahina Djaoudi, France Van Wambeke, Aude Barani, Nagib Bhairy, Servanne Chevaillier, Karine Desboeufs, Sandra Nunige, Mohamed Labiadh, Thierry Henry des Tureaux, Dominique Lefèvre, Amel Nouara, Christos Panagiotopoulos, Marc Tedetti, and Elvira Pulido-Villena
Biogeosciences, 17, 6271–6285, https://doi.org/10.5194/bg-17-6271-2020, https://doi.org/10.5194/bg-17-6271-2020, 2020
Cécile Guieu, Fabrizio D'Ortenzio, François Dulac, Vincent Taillandier, Andrea Doglioli, Anne Petrenko, Stéphanie Barrillon, Marc Mallet, Pierre Nabat, and Karine Desboeufs
Biogeosciences, 17, 5563–5585, https://doi.org/10.5194/bg-17-5563-2020, https://doi.org/10.5194/bg-17-5563-2020, 2020
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We describe here the objectives and strategy of the PEACETIME project and cruise, dedicated to dust deposition and its impacts in the Mediterranean Sea. Our strategy to go a step further forward than in previous approaches in understanding these impacts by catching a real deposition event at sea is detailed. We summarize the work performed at sea, the type of data acquired and their valorization in the papers published in the special issue.
Yuri Galletti, Silvia Becagli, Alcide di Sarra, Margherita Gonnelli, Elvira Pulido-Villena, Damiano M. Sferlazzo, Rita Traversi, Stefano Vestri, and Chiara Santinelli
Biogeosciences, 17, 3669–3684, https://doi.org/10.5194/bg-17-3669-2020, https://doi.org/10.5194/bg-17-3669-2020, 2020
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This paper reports the first data about atmospheric deposition of dissolved organic matter (DOM) on the island of Lampedusa. It also shows the implications for the surface marine layer by studying the impact of atmospheric organic carbon deposition in the marine ecosystem. It is a preliminary study, but it is pioneering and important for having new data that can be crucial in order to understand the impact of atmospheric deposition on the marine carbon cycle in a global climate change scenario.
Elena Terzić, Paolo Lazzari, Emanuele Organelli, Cosimo Solidoro, Stefano Salon, Fabrizio D'Ortenzio, and Pascal Conan
Biogeosciences, 16, 2527–2542, https://doi.org/10.5194/bg-16-2527-2019, https://doi.org/10.5194/bg-16-2527-2019, 2019
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Measuring ecosystem properties in the ocean is a hard business. Recent availability of data from Biogeochemical-Argo floats can help make this task easier. Numerical models can integrate these new data in a coherent picture and can be used to investigate the functioning of ecosystem processes. Our new approach merges experimental information and model capabilities to quantitatively demonstrate the importance of light and water vertical mixing for algae dynamics in the Mediterranean Sea.
Marie Barbieux, Julia Uitz, Bernard Gentili, Orens Pasqueron de Fommervault, Alexandre Mignot, Antoine Poteau, Catherine Schmechtig, Vincent Taillandier, Edouard Leymarie, Christophe Penkerc'h, Fabrizio D'Ortenzio, Hervé Claustre, and Annick Bricaud
Biogeosciences, 16, 1321–1342, https://doi.org/10.5194/bg-16-1321-2019, https://doi.org/10.5194/bg-16-1321-2019, 2019
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As commonly observed in oligotrophic stratified waters, a subsurface (or deep) chlorophyll maximum (SCM) frequently characterizes the vertical distribution of phytoplankton chlorophyll in the Mediterranean Sea. SCMs often result from photoacclimation of the phytoplankton organisms. However they can also result from an actual increase in phytoplankton carbon biomass. Our results also suggest that a variety of intermediate types of SCMs are encountered between these two endmember situations.
Julien Palmiéri, Jean-Claude Dutay, Fabrizio D'Ortenzio, Loïc Houpert, Nicolas Mayot, and Laurent Bopp
Biogeosciences Discuss., https://doi.org/10.5194/bg-2018-423, https://doi.org/10.5194/bg-2018-423, 2018
Manuscript not accepted for further review
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In this model study, we highlight the importance of the subsurface phytoplankton dynamic in the Mediterranean sea. Comparing surface chlorophyll annual cycle to vertically integrated one, we show how important the subsurface phytoplankton community is, throughout the Mediterranean. It shows that surface chlorophyll is incomplete and cannot alone be considered a good proxy of the total phytoplankton biomass. Then, we decrypt some deep chlorophyll maximum mechanisms in the low production area.
Chiara Santinelli, Roberto Iacono, Ernesto Napolitano, and Maurizio Ribera d'Alcalá
Biogeosciences Discuss., https://doi.org/10.5194/bg-2018-418, https://doi.org/10.5194/bg-2018-418, 2018
Revised manuscript not accepted
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Part of the energy in the ocean is stored as dissolved organic carbon. Water moves around, bringing this energy from one place to another, down to the deep layers and up again. Here, we show that horizontal currents can have a strong impact on the carbon cycle, because they can transport chemical energy far away, establishing links between distant areas of the ocean and feeding regions in which the local accumulation of chemical energy is low.
Héloise Lavigne, Giuseppe Civitarese, Miroslav Gačić, and Fabrizio D'Ortenzio
Biogeosciences, 15, 4431–4445, https://doi.org/10.5194/bg-15-4431-2018, https://doi.org/10.5194/bg-15-4431-2018, 2018
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The north Ionian circulation, which is characterized by a decadal alternation of cyclonic and anticyclonic regime, affects phytoplankton dynamics and surface chlorophyll a. From satellite ocean color data, the cyclonic and anticyclonic regimes are compared and two chlorophyll a dynamics are observed: when circulation is anticyclonic, bloom initiation is in December and chlorophyll is low in March, whereas during the cyclonic regime, a late chlorophyll peak is commonly observed in March.
Vincent Taillandier, Thibaut Wagener, Fabrizio D'Ortenzio, Nicolas Mayot, Hervé Legoff, Joséphine Ras, Laurent Coppola, Orens Pasqueron de Fommervault, Catherine Schmechtig, Emilie Diamond, Henry Bittig, Dominique Lefevre, Edouard Leymarie, Antoine Poteau, and Louis Prieur
Earth Syst. Sci. Data, 10, 627–641, https://doi.org/10.5194/essd-10-627-2018, https://doi.org/10.5194/essd-10-627-2018, 2018
Short summary
Short summary
We report on data from an oceanographic cruise, covering western, central and eastern parts of the Mediterranean Sea. This cruise was fully dedicated to the maintenance and the metrological verification of a biogeochemical observing system based on a fleet of BGC-Argo floats.
Emanuele Organelli, Marie Barbieux, Hervé Claustre, Catherine Schmechtig, Antoine Poteau, Annick Bricaud, Emmanuel Boss, Nathan Briggs, Giorgio Dall'Olmo, Fabrizio D'Ortenzio, Edouard Leymarie, Antoine Mangin, Grigor Obolensky, Christophe Penkerc'h, Louis Prieur, Collin Roesler, Romain Serra, Julia Uitz, and Xiaogang Xing
Earth Syst. Sci. Data, 9, 861–880, https://doi.org/10.5194/essd-9-861-2017, https://doi.org/10.5194/essd-9-861-2017, 2017
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Autonomous robotic platforms such as Biogeochemical-Argo floats allow observation of the ocean, from the surface to the interior, in a new and systematic way. A fleet of 105 of these platforms have collected several biological, biogeochemical, and optical variables in still unexplored regions. The quality-controlled databases presented here will enable scientists to improve knowledge on the functioning of marine ecosystems and investigate the climatic implications.
Nicolas Mayot, Fabrizio D'Ortenzio, Maurizio Ribera d'Alcalà, Héloïse Lavigne, and Hervé Claustre
Biogeosciences, 13, 1901–1917, https://doi.org/10.5194/bg-13-1901-2016, https://doi.org/10.5194/bg-13-1901-2016, 2016
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The present manuscript provides an analysis of the interannual variability of the phytoplankton seasonality in the Mediterranean Sea, based on 16 years of ocean color data. Important interannual variabilities at regional scale were highlighted and related to environmental factors. Our results demonstrate also that seasonal patterns retrieved from satellite allow to identify the evolution of an oceanic area and to summarize the huge quantity of information that the satellite data offer.
R. Sauzède, H. Lavigne, H. Claustre, J. Uitz, C. Schmechtig, F. D'Ortenzio, C. Guinet, and S. Pesant
Earth Syst. Sci. Data, 7, 261–273, https://doi.org/10.5194/essd-7-261-2015, https://doi.org/10.5194/essd-7-261-2015, 2015
H. Lavigne, F. D'Ortenzio, M. Ribera D'Alcalà, H. Claustre, R. Sauzède, and M. Gacic
Biogeosciences, 12, 5021–5039, https://doi.org/10.5194/bg-12-5021-2015, https://doi.org/10.5194/bg-12-5021-2015, 2015
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The spatiotemporal variability in the vertical distribution of the chlorophyll concentration in the Mediterranean Sea is investigated. Results are based on a large database of fluorescence profiles intercalibrated from ocean color satellite data. They indicate that two types of chlorophyll seasonality coexist in the Mediterranean Sea. The shape of the chlorophyll profile is very dynamic during winter, and the deep chlorophyll maximum is a dominant feature of Mediterranean chlorophyll profile.
E. Pulido-Villena, A.-C. Baudoux, I. Obernosterer, M. Landa, J. Caparros, P. Catala, C. Georges, J. Harmand, and C. Guieu
Biogeosciences, 11, 5607–5619, https://doi.org/10.5194/bg-11-5607-2014, https://doi.org/10.5194/bg-11-5607-2014, 2014
C. Guieu, C. Ridame, E. Pulido-Villena, M. Bressac, K. Desboeufs, and F. Dulac
Biogeosciences, 11, 5621–5635, https://doi.org/10.5194/bg-11-5621-2014, https://doi.org/10.5194/bg-11-5621-2014, 2014
C. Guinet, X. Xing, E. Walker, P. Monestiez, S. Marchand, B. Picard, T. Jaud, M. Authier, C. Cotté, A. C. Dragon, E. Diamond, D. Antoine, P. Lovell, S. Blain, F. D'Ortenzio, and H. Claustre
Earth Syst. Sci. Data, 5, 15–29, https://doi.org/10.5194/essd-5-15-2013, https://doi.org/10.5194/essd-5-15-2013, 2013
Related subject area
Biogeochemistry: Open Ocean
Climate-driven shifts in Southern Ocean primary producers and biogeochemistry in CMIP6 models
Ocean acidification trends and carbonate system dynamics across the North Atlantic subpolar gyre water masses during 2009–2019
Sedimentary organic matter signature hints at the phytoplankton-driven biological carbon pump in the central Arabian Sea
Hydrological cycle amplification imposes spatial patterns on the climate change response of ocean pH and carbonate chemistry
Phytoplankton responses to iron and macronutrient fluxes from subsurface waters in the western North Pacific in summer
Assessing the tropical Atlantic biogeochemical processes in the Norwegian Earth System Model
Evolution of oxygen and stratification and their relationship in the North Pacific Ocean in CMIP6 Earth system models
Evaluation of CMIP6 model performance in simulating historical biogeochemistry across the southern South China Sea
Drivers of decadal trends in the ocean carbon sink in the past, present, and future in Earth system models
Anthropogenic carbon storage and its decadal changes in the Atlantic between 1990–2020
Ocean alkalinity enhancement impacts: regrowth of marine microalgae in alkaline mineral concentrations simulating the initial concentrations after ship-based dispersions
Inadequacies in the representation of sub-seasonal phytoplankton dynamics in Earth system models
Climatic controls on metabolic constraints in the ocean
Effects of grain size and seawater salinity on magnesium hydroxide dissolution and secondary calcium carbonate precipitation kinetics: implications for ocean alkalinity enhancement
Hybrid model estimate of the ocean carbon sink from 1959 to 2022
Relationships between the concentration of particulate organic nitrogen and the inherent optical properties of seawater in oceanic surface waters
Spatial distributions of iron and manganese in surface waters in the Arctic’s Laptev and East Siberian seas
Short-term response of Emiliania huxleyi growth and morphology to abrupt salinity stress
Massive and localized export of selected marine snow types at eddy edges in the South Atlantic Ocean
Assessing the impact of CO2-equilibrated ocean alkalinity enhancement on microbial metabolic rates in an oligotrophic system
Phosphomonoesterase and phosphodiesterase activities in the eastern Mediterranean in two contrasting seasonal situations
Net primary production annual maxima in the North Atlantic projected to shift in the 21st century
Testing the influence of light on nitrite cycling in the eastern tropical North Pacific
Loss of nitrogen via anaerobic ammonium oxidation (anammox) in the California Current system during the late Quaternary
Technical note: Assessment of float pH data quality control methods – a case study in the subpolar northwest Atlantic Ocean
Linking northeastern North Pacific oxygen changes to upstream surface outcrop variations
Ocean alkalinity enhancement in an open ocean ecosystem: Biogeochemical responses and carbon storage durability
Underestimation of multi-decadal global O2 loss due to an optimal interpolation method
Reviews and syntheses: expanding the global coverage of gross primary production and net community production measurements using Biogeochemical-Argo floats
Characteristics of surface physical and biogeochemical parameters within mesoscale eddies in the Southern Ocean
Seasonal dynamics and annual budget of dissolved inorganic carbon in the northwestern Mediterranean deep-convection region
The fingerprint of climate variability on the surface ocean cycling of iron and its isotopes
Reconstructing the ocean's mesopelagic zone carbon budget: sensitivity and estimation of parameters associated with prokaryotic remineralization
Seasonal cycles of biogeochemical fluxes in the Scotia Sea, Southern Ocean: a stable isotope approach
Absence of photophysiological response to iron addition in autumn phytoplankton in the Antarctic sea-ice zone
Optimal parameters for the ocean's nutrient, carbon, and oxygen cycles compensate for circulation biases but replumb the biological pump
Importance of multiple sources of iron for the upper-ocean biogeochemistry over the northern Indian Ocean
Exploring the role of different data types and timescales in the quality of marine biogeochemical model calibration
All about nitrite: exploring nitrite sources and sinks in the eastern tropical North Pacific oxygen minimum zone
Fossil coccolith morphological attributes as a new proxy for deep ocean carbonate chemistry
Reconstructing ocean carbon storage with CMIP6 Earth system models and synthetic Argo observations
Using machine learning and Biogeochemical-Argo (BGC-Argo) floats to assess biogeochemical models and optimize observing system design
The representation of alkalinity and the carbonate pump from CMIP5 to CMIP6 Earth system models and implications for the carbon cycle
Model estimates of metazoans' contributions to the biological carbon pump
Tracing differences in iron supply to the Mid-Atlantic Ridge valley between hydrothermal vent sites: implications for the addition of iron to the deep ocean
Nitrite cycling in the primary nitrite maxima of the eastern tropical North Pacific
Hotspots and drivers of compound marine heatwaves and low net primary production extremes
Ecosystem impacts of marine heat waves in the northeast Pacific
Tracing the role of Arctic shelf processes in Si and N cycling and export through the Fram Strait: insights from combined silicon and nitrate isotopes
Controls on the relative abundances and rates of nitrifying microorganisms in the ocean
Ben J. Fisher, Alex J. Poulton, Michael P. Meredith, Kimberlee Baldry, Oscar Schofield, and Sian F. Henley
Biogeosciences, 22, 975–994, https://doi.org/10.5194/bg-22-975-2025, https://doi.org/10.5194/bg-22-975-2025, 2025
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The Southern Ocean is a rapidly warming environment, with subsequent impacts on ecosystems and biogeochemical cycling. This study examines changes in phytoplankton and biogeochemistry using a range of climate models. Under climate change, the Southern Ocean will be warmer, more acidic and more productive and will have reduced nutrient availability by 2100. However, there is substantial variability between models across key productivity parameters. We propose ways of reducing this uncertainty.
David Curbelo-Hernández, Fiz F. Pérez, Melchor González-Dávila, Sergey V. Gladyshev, Aridane G. González, David González-Santana, Antón Velo, Alexey Sokov, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 5561–5589, https://doi.org/10.5194/bg-21-5561-2024, https://doi.org/10.5194/bg-21-5561-2024, 2024
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The study evaluated CO2–carbonate system dynamics in the North Atlantic subpolar gyre during 2009–2019. Significant ocean acidification, largely due to rising anthropogenic CO2 levels, was found. Cooling, freshening, and enhanced convective processes intensified this trend, affecting calcite and aragonite saturation. The findings contribute to a deeper understanding of ocean acidification and improve our knowledge about its impact on marine ecosystems.
Medhavi Pandey, Haimanti Biswas, Daniel Birgel, Nicole Burdanowitz, and Birgit Gaye
Biogeosciences, 21, 4681–4698, https://doi.org/10.5194/bg-21-4681-2024, https://doi.org/10.5194/bg-21-4681-2024, 2024
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We analysed sea surface temperature (SST) proxy and plankton biomarkers in sediments that accumulate sinking material signatures from surface waters in the central Arabian Sea (21°–11° N, 64° E), a tropical basin impacted by monsoons. We saw a north–south SST gradient, and the biological proxies showed more organic matter from larger algae in the north. Smaller algae and zooplankton were more numerous in the south. These trends were related to ocean–atmospheric processes and oxygen availability.
Allison Hogikyan and Laure Resplandy
Biogeosciences, 21, 4621–4636, https://doi.org/10.5194/bg-21-4621-2024, https://doi.org/10.5194/bg-21-4621-2024, 2024
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Rising atmospheric CO2 influences ocean carbon chemistry, leading to ocean acidification. Global warming introduces spatial patterns in the intensity of ocean acidification. We show that the most prominent spatial patterns are controlled by warming-driven changes in rainfall and evaporation, not by the direct effect of warming on carbon chemistry and pH. These evaporation and rainfall patterns oppose acidification in saltier parts of the ocean and enhance acidification in fresher regions.
Huailin Deng, Koji Suzuki, Ichiro Yasuda, Hiroshi Ogawa, and Jun Nishioka
EGUsphere, https://doi.org/10.5194/egusphere-2024-3064, https://doi.org/10.5194/egusphere-2024-3064, 2024
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Iron (Fe) and nitrate are vital for primary production in the North Pacific. Sedimentary Fe is carried by North Pacific Intermediate Water to the north Pacific, but the nutrient return path and its effect on phytoplankton are unclear. By combining Fe and macronutrient fluxes with phytoplankton composition, this study firstly revealed that Fe supply from subsurface greatly controls diatom abundance and identified the nutrient return path in the subarctic gyre and Kuroshio-Oyashio Transition Area.
Shunya Koseki, Lander R. Crespo, Jerry Tjiputra, Filippa Fransner, Noel S. Keenlyside, and David Rivas
Biogeosciences, 21, 4149–4168, https://doi.org/10.5194/bg-21-4149-2024, https://doi.org/10.5194/bg-21-4149-2024, 2024
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We investigated how the physical biases of an Earth system model influence the marine biogeochemical processes in the tropical Atlantic. With four different configurations of the model, we have shown that the versions with better SST reproduction tend to better represent the primary production and air–sea CO2 flux in terms of climatology, seasonal cycle, and response to climate variability.
Lyuba Novi, Annalisa Bracco, Takamitsu Ito, and Yohei Takano
Biogeosciences, 21, 3985–4005, https://doi.org/10.5194/bg-21-3985-2024, https://doi.org/10.5194/bg-21-3985-2024, 2024
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We explored the relationship between oxygen and stratification in the North Pacific Ocean using a combination of data mining and machine learning. We used isopycnic potential vorticity (IPV) as an indicator to quantify ocean ventilation and analyzed its predictability, a strong O2–IPV connection, and predictability for IPV in the tropical Pacific. This opens new routes for monitoring ocean O2 through few observational sites co-located with more abundant IPV measurements in the tropical Pacific.
Winfred Marshal, Jing Xiang Chung, Nur Hidayah Roseli, Roswati Md Amin, and Mohd Fadzil Bin Mohd Akhir
Biogeosciences, 21, 4007–4035, https://doi.org/10.5194/bg-21-4007-2024, https://doi.org/10.5194/bg-21-4007-2024, 2024
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This study stands out for thoroughly examining CMIP6 ESMs' ability to simulate biogeochemical variables in the southern South China Sea, an economically important region. It assesses variables like chlorophyll, phytoplankton, nitrate, and oxygen on annual and seasonal scales. While global assessments exist, this study addresses a gap by objectively ranking 13 CMIP6 ocean biogeochemistry models' performance at a regional level, focusing on replicating specific observed biogeochemical variables.
Jens Terhaar
Biogeosciences, 21, 3903–3926, https://doi.org/10.5194/bg-21-3903-2024, https://doi.org/10.5194/bg-21-3903-2024, 2024
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Despite the ocean’s importance in the carbon cycle and hence the climate, observing the ocean carbon sink remains challenging. Here, I use an ensemble of 12 models to understand drivers of decadal trends of the past, present, and future ocean carbon sink. I show that 80 % of the decadal trends in the multi-model mean ocean carbon sink can be explained by changes in decadal trends in atmospheric CO2. The remaining 20 % are due to internal climate variability and ocean heat uptake.
Reiner Steinfeldt, Monika Rhein, and Dagmar Kieke
Biogeosciences, 21, 3839–3867, https://doi.org/10.5194/bg-21-3839-2024, https://doi.org/10.5194/bg-21-3839-2024, 2024
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We calculate the amount of anthropogenic carbon (Cant) in the Atlantic for the years 1990, 2000, 2010 and 2020. Cant is the carbon that is taken up by the ocean as a result of humanmade CO2 emissions. To determine the amount of Cant, we apply a technique that is based on the observations of other humanmade gases (e.g., chlorofluorocarbons). Regionally, changes in ocean ventilation have an impact on the storage of Cant. Overall, the increase in Cant is driven by the rising CO2 in the atmosphere.
Stephanie Delacroix, Tor Jensen Nystuen, August E. Dessen Tobiesen, Andrew L. King, and Erik Höglund
Biogeosciences, 21, 3677–3690, https://doi.org/10.5194/bg-21-3677-2024, https://doi.org/10.5194/bg-21-3677-2024, 2024
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The addition of alkaline minerals into the ocean might reduce excessive anthropogenic CO2 emissions. Magnesium hydroxide can be added in large amounts because of its low seawater solubility without reaching harmful pH levels. The toxicity effect results of magnesium hydroxide, by simulating the expected concentrations from a ship's dispersion scenario, demonstrated low impacts on both sensitive and local assemblages of marine microalgae when compared to calcium hydroxide.
Madhavan Girijakumari Keerthi, Olivier Aumont, Lester Kwiatkowski, and Marina Levy
EGUsphere, https://doi.org/10.5194/egusphere-2024-2294, https://doi.org/10.5194/egusphere-2024-2294, 2024
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Our study assesses the capability of CMIP6 models to reproduce satellite observations of sub-seasonal chlorophyll variability. Models struggle to reproduce the sub-seasonal variance and its contribution across timescales. Some models overestimate sub-seasonal variance and exaggerate its role in annual fluctuations, while others underestimate it. Underestimation is likely due to the coarse resolution of models, while overestimation may result from intrinsic oscillations in biogeochemical models.
Precious Mongwe, Matthew Long, Takamitsu Ito, Curtis Deutsch, and Yeray Santana-Falcón
Biogeosciences, 21, 3477–3490, https://doi.org/10.5194/bg-21-3477-2024, https://doi.org/10.5194/bg-21-3477-2024, 2024
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We use a collection of measurements that capture the physiological sensitivity of organisms to temperature and oxygen and a CESM1 large ensemble to investigate how natural climate variations and climate warming will impact the ability of marine heterotrophic marine organisms to support habitats in the future. We find that warming and dissolved oxygen loss over the next several decades will reduce the volume of ocean habitats and will increase organisms' vulnerability to extremes.
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.
Jens Terhaar
EGUsphere, https://doi.org/10.5194/egusphere-2024-2171, https://doi.org/10.5194/egusphere-2024-2171, 2024
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The ocean is a major natural carbon sink. Despite its importance, estimates of the ocean carbon sink remain uncertain. Here, I present a hybrid model estimate of the ocean carbon sink from 1959 to 2022. By combining ocean models in hindcast mode and Earth System Models, I keep the strength of each approach and remove the respective weaknesses. This hybrid model estimate is similar in magnitude than the best estimate of the Global Carbon Budget but 70 % less uncertain.
Alain Fumenia, Hubert Loisel, Rick Allen Reynolds, and Dariusz Stramski
EGUsphere, https://doi.org/10.5194/egusphere-2024-2218, https://doi.org/10.5194/egusphere-2024-2218, 2024
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Particulate organic nitrogen (PON) in the ocean refers to nitrogen contained in particles suspended such as phytoplankton, zooplankton, bacteria, viruses, and organic detritus. We used field measurements to determine relationships between PON and inherent optical properties of seawater across a broad range of marine environments. The presented relationships are expected to have application in the assessment of PON distribution and variations from in situ and satellite optical observations
Naoya Kanna, Kazutaka Tateyama, Takuji Waseda, Anna Timofeeva, Maria Papadimitraki, Laura Whitmore, Hajime Obata, Daiki Nomura, Hiroshi Ogawa, Youhei Yamashita, and Igor Polyakov
EGUsphere, https://doi.org/10.5194/egusphere-2024-1834, https://doi.org/10.5194/egusphere-2024-1834, 2024
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This article presents data on iron and manganese, which are essential micronutrients for primary producers, on the surface of the Arctic’s Laptev and East Siberian Seas (LESS). Observations were made in international cooperation with the NABOS expedition during the late summer of 2021 in the Arctic Ocean. The results from this study indicate that the major factors controlling these metal concentrations in LESS are river discharge and the input of shelf sediment.
Rosie M. Sheward, Christina Gebühr, Jörg Bollmann, and Jens O. Herrle
Biogeosciences, 21, 3121–3141, https://doi.org/10.5194/bg-21-3121-2024, https://doi.org/10.5194/bg-21-3121-2024, 2024
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How quickly do marine microorganisms respond to salinity stress? Our experiments with the calcifying marine plankton Emiliania huxleyi show that growth and cell morphology responded to salinity stress within as little as 24–48 hours, demonstrating that morphology and calcification are sensitive to salinity over a range of timescales. Our results have implications for understanding the short-term role of E. huxleyi in biogeochemical cycles and in size-based paleoproxies for salinity.
Alexandre Accardo, Rémi Laxenaire, Alberto Baudena, Sabrina Speich, Rainer Kiko, and Lars Stemmann
EGUsphere, https://doi.org/10.5194/egusphere-2024-1558, https://doi.org/10.5194/egusphere-2024-1558, 2024
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The open ocean helps mitigate climate change by storing CO2 through the biological carbon pump (BCP). The BCP involves processes like phytoplankton capturing CO2 and sequestering it in the deep ocean via marine snow production. We found significant marine snow accumulation from the surface to 600 meters deep in frontal regions between eddies. We suggest that the coupling of hydrodynamics at eddy edges and biological activity (via planktonic organisms) may enhanced this process.
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.
France Van Wambeke, Pascal Conan, Mireille Pujo-Pay, Vincent Taillandier, Olivier Crispi, Alexandra Pavlidou, Sandra Nunige, Morgane Didry, Christophe Salmeron, and Elvira Pulido-Villena
Biogeosciences, 21, 2621–2640, https://doi.org/10.5194/bg-21-2621-2024, https://doi.org/10.5194/bg-21-2621-2024, 2024
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Phosphomonoesterase (PME) and phosphodiesterase (PDE) activities over the epipelagic zone are described in the eastern Mediterranean Sea in winter and autumn. The types of concentration kinetics obtained for PDE (saturation at 50 µM, high Km, high turnover times) compared to those of PME (saturation at 1 µM, low Km, low turnover times) are discussed in regard to the possible inequal distribution of PDE and PME in the size continuum of organic material and accessibility to phosphodiesters.
Jenny Hieronymus, Magnus Hieronymus, Matthias Gröger, Jörg Schwinger, Raffaele Bernadello, Etienne Tourigny, Valentina Sicardi, Itzel Ruvalcaba Baroni, and Klaus Wyser
Biogeosciences, 21, 2189–2206, https://doi.org/10.5194/bg-21-2189-2024, https://doi.org/10.5194/bg-21-2189-2024, 2024
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The timing of the net primary production annual maxima in the North Atlantic in the period 1750–2100 is investigated using two Earth system models and the high-emissions scenario SSP5-8.5. It is found that, for most of the region, the annual maxima occur progressively earlier, with the most change occurring after the year 2000. Shifts in the seasonality of the primary production may impact the entire ecosystem, which highlights the need for long-term monitoring campaigns in this area.
Nicole M. Travis, Colette L. Kelly, and Karen L. Casciotti
Biogeosciences, 21, 1985–2004, https://doi.org/10.5194/bg-21-1985-2024, https://doi.org/10.5194/bg-21-1985-2024, 2024
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We conducted experimental manipulations of light level on microbial communities from the primary nitrite maximum. Overall, while individual microbial processes have different directions and magnitudes in their response to increasing light, the net community response is a decline in nitrite production with increasing light. We conclude that while increased light may decrease net nitrite production, high-light conditions alone do not exclude nitrification from occurring in the surface ocean.
Zoë Rebecca van Kemenade, Zeynep Erdem, Ellen Christine Hopmans, Jaap Smede Sinninghe Damsté, and Darci Rush
Biogeosciences, 21, 1517–1532, https://doi.org/10.5194/bg-21-1517-2024, https://doi.org/10.5194/bg-21-1517-2024, 2024
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The California Current system (CCS) hosts the eastern subtropical North Pacific oxygen minimum zone (ESTNP OMZ). This study shows anaerobic ammonium oxidizing (anammox) bacteria cause a loss of bioavailable nitrogen (N) in the ESTNP OMZ throughout the late Quaternary. Anammox occurred during both glacial and interglacial periods and was driven by the supply of organic matter and changes in ocean currents. These findings may have important consequences for biogeochemical models of the CCS.
Cathy Wimart-Rousseau, Tobias Steinhoff, Birgit Klein, Henry Bittig, and Arne Körtzinger
Biogeosciences, 21, 1191–1211, https://doi.org/10.5194/bg-21-1191-2024, https://doi.org/10.5194/bg-21-1191-2024, 2024
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The marine CO2 system can be measured independently and continuously by BGC-Argo floats since numerous pH sensors have been developed to suit these autonomous measurements platforms. By applying the Argo correction routines to float pH data acquired in the subpolar North Atlantic Ocean, we report the uncertainty and lack of objective criteria associated with the choice of the reference method as well the reference depth for the pH correction.
Sabine Mecking and Kyla Drushka
Biogeosciences, 21, 1117–1133, https://doi.org/10.5194/bg-21-1117-2024, https://doi.org/10.5194/bg-21-1117-2024, 2024
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This study investigates whether northeastern North Pacific oxygen changes may be caused by surface density changes in the northwest as water moves along density horizons from the surface into the subsurface ocean. A correlation is found with a lag that about matches the travel time of water from the northwest to the northeast. Salinity is the main driver causing decadal changes in surface density, whereas salinity and temperature contribute about equally to long-term declining density trends.
Allanah Joy Paul, Mathias Haunost, Silvan Urs Goldenberg, Jens Hartmann, Nicolás Sánchez, Julieta Schneider, Niels Suitner, and Ulf Riebesell
EGUsphere, https://doi.org/10.5194/egusphere-2024-417, https://doi.org/10.5194/egusphere-2024-417, 2024
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Ocean alkalinity enhancement (OAE) is being assessed for its potential to absorb atmospheric CO2 and store it for a long time. OAE still needs comprehensive assessment of its safety and effectiveness. We studied an idealised OAE application in a natural low nutrient ecosystem over one month. Our results showed that biogeochemical functioning remained mostly stable, but that the long-term capability for storing carbon may be limited at high alkalinity concentration.
Takamitsu Ito, Hernan E. Garcia, Zhankun Wang, Shoshiro Minobe, Matthew C. Long, Just Cebrian, James Reagan, Tim Boyer, Christopher Paver, Courtney Bouchard, Yohei Takano, Seth Bushinsky, Ahron Cervania, and Curtis A. Deutsch
Biogeosciences, 21, 747–759, https://doi.org/10.5194/bg-21-747-2024, https://doi.org/10.5194/bg-21-747-2024, 2024
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This study aims to estimate how much oceanic oxygen has been lost and its uncertainties. One major source of uncertainty comes from the statistical gap-filling methods. Outputs from Earth system models are used to generate synthetic observations where oxygen data are extracted from the model output at the location and time of historical oceanographic cruises. Reconstructed oxygen trend is approximately two-thirds of the true trend.
Robert W. Izett, Katja Fennel, Adam C. Stoer, and David P. Nicholson
Biogeosciences, 21, 13–47, https://doi.org/10.5194/bg-21-13-2024, https://doi.org/10.5194/bg-21-13-2024, 2024
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This paper provides an overview of the capacity to expand the global coverage of marine primary production estimates using autonomous ocean-going instruments, called Biogeochemical-Argo floats. We review existing approaches to quantifying primary production using floats, provide examples of the current implementation of the methods, and offer insights into how they can be better exploited. This paper is timely, given the ongoing expansion of the Biogeochemical-Argo array.
Qian Liu, Yingjie Liu, and Xiaofeng Li
Biogeosciences, 20, 4857–4874, https://doi.org/10.5194/bg-20-4857-2023, https://doi.org/10.5194/bg-20-4857-2023, 2023
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In the Southern Ocean, abundant eddies behave opposite to our expectations. That is, anticyclonic (cyclonic) eddies are cold (warm). By investigating the variations of physical and biochemical parameters in eddies, we find that abnormal eddies have unique and significant effects on modulating the parameters. This study fills a gap in understanding the effects of abnormal eddies on physical and biochemical parameters in the Southern Ocean.
Caroline Ulses, Claude Estournel, Patrick Marsaleix, Karline Soetaert, Marine Fourrier, Laurent Coppola, Dominique Lefèvre, Franck Touratier, Catherine Goyet, Véronique Guglielmi, Fayçal Kessouri, Pierre Testor, and Xavier Durrieu de Madron
Biogeosciences, 20, 4683–4710, https://doi.org/10.5194/bg-20-4683-2023, https://doi.org/10.5194/bg-20-4683-2023, 2023
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Deep convection plays a key role in the circulation, thermodynamics, and biogeochemical cycles in the Mediterranean Sea, considered to be a hotspot of biodiversity and climate change. In this study, we investigate the seasonal and annual budget of dissolved inorganic carbon in the deep-convection area of the northwestern Mediterranean Sea.
Daniela König and Alessandro Tagliabue
Biogeosciences, 20, 4197–4212, https://doi.org/10.5194/bg-20-4197-2023, https://doi.org/10.5194/bg-20-4197-2023, 2023
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Using model simulations, we show that natural and anthropogenic changes in the global climate leave a distinct fingerprint in the isotopic signatures of iron in the surface ocean. We find that these climate effects on iron isotopes are often caused by the redistribution of iron from different external sources to the ocean, due to changes in ocean currents, and by changes in algal growth, which take up iron. Thus, isotopes may help detect climate-induced changes in iron supply and algal uptake.
Chloé Baumas, Robin Fuchs, Marc Garel, Jean-Christophe Poggiale, Laurent Memery, Frédéric A. C. Le Moigne, and Christian Tamburini
Biogeosciences, 20, 4165–4182, https://doi.org/10.5194/bg-20-4165-2023, https://doi.org/10.5194/bg-20-4165-2023, 2023
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Through the sink of particles in the ocean, carbon (C) is exported and sequestered when reaching 1000 m. Attempts to quantify C exported vs. C consumed by heterotrophs have increased. Yet most of the conducted estimations have led to C demands several times higher than C export. The choice of parameters greatly impacts the results. As theses parameters are overlooked, non-accurate values are often used. In this study we show that C budgets can be well balanced when using appropriate values.
Anna Belcher, Sian F. Henley, Katharine Hendry, Marianne Wootton, Lisa Friberg, Ursula Dallman, Tong Wang, Christopher Coath, and Clara Manno
Biogeosciences, 20, 3573–3591, https://doi.org/10.5194/bg-20-3573-2023, https://doi.org/10.5194/bg-20-3573-2023, 2023
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The oceans play a crucial role in the uptake of atmospheric carbon dioxide, particularly the Southern Ocean. The biological pumping of carbon from the surface to the deep ocean is key to this. Using sediment trap samples from the Scotia Sea, we examine biogeochemical fluxes of carbon, nitrogen, and biogenic silica and their stable isotope compositions. We find phytoplankton community structure and physically mediated processes are important controls on particulate fluxes to the deep ocean.
Asmita Singh, Susanne Fietz, Sandy J. Thomalla, Nicolas Sanchez, Murat V. Ardelan, Sébastien Moreau, Hanna M. Kauko, Agneta Fransson, Melissa Chierici, Saumik Samanta, Thato N. Mtshali, Alakendra N. Roychoudhury, and Thomas J. Ryan-Keogh
Biogeosciences, 20, 3073–3091, https://doi.org/10.5194/bg-20-3073-2023, https://doi.org/10.5194/bg-20-3073-2023, 2023
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Despite the scarcity of iron in the Southern Ocean, seasonal blooms occur due to changes in nutrient and light availability. Surprisingly, during an autumn bloom in the Antarctic sea-ice zone, the results from incubation experiments showed no significant photophysiological response of phytoplankton to iron addition. This suggests that ambient iron concentrations were sufficient, challenging the notion of iron deficiency in the Southern Ocean through extended iron-replete post-bloom conditions.
Benoît Pasquier, Mark Holzer, Matthew A. Chamberlain, Richard J. Matear, Nathaniel L. Bindoff, and François W. Primeau
Biogeosciences, 20, 2985–3009, https://doi.org/10.5194/bg-20-2985-2023, https://doi.org/10.5194/bg-20-2985-2023, 2023
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Modeling the ocean's carbon and oxygen cycles accurately is challenging. Parameter optimization improves the fit to observed tracers but can introduce artifacts in the biological pump. Organic-matter production and subsurface remineralization rates adjust to compensate for circulation biases, changing the pathways and timescales with which nutrients return to the surface. Circulation biases can thus strongly alter the system’s response to ecological change, even when parameters are optimized.
Priyanka Banerjee
Biogeosciences, 20, 2613–2643, https://doi.org/10.5194/bg-20-2613-2023, https://doi.org/10.5194/bg-20-2613-2023, 2023
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This study shows that atmospheric deposition is the most important source of iron to the upper northern Indian Ocean for phytoplankton growth. This is followed by iron from continental-shelf sediment. Phytoplankton increase following iron addition is possible only with high background levels of nitrate. Vertical mixing is the most important physical process supplying iron to the upper ocean in this region throughout the year. The importance of ocean currents in supplying iron varies seasonally.
Iris Kriest, Julia Getzlaff, Angela Landolfi, Volkmar Sauerland, Markus Schartau, and Andreas Oschlies
Biogeosciences, 20, 2645–2669, https://doi.org/10.5194/bg-20-2645-2023, https://doi.org/10.5194/bg-20-2645-2023, 2023
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Global biogeochemical ocean models are often subjectively assessed and tuned against observations. We applied different strategies to calibrate a global model against observations. Although the calibrated models show similar tracer distributions at the surface, they differ in global biogeochemical fluxes, especially in global particle flux. Simulated global volume of oxygen minimum zones varies strongly with calibration strategy and over time, rendering its temporal extrapolation difficult.
John C. Tracey, Andrew R. Babbin, Elizabeth Wallace, Xin Sun, Katherine L. DuRussel, Claudia Frey, Donald E. Martocello III, Tyler Tamasi, Sergey Oleynik, and Bess B. Ward
Biogeosciences, 20, 2499–2523, https://doi.org/10.5194/bg-20-2499-2023, https://doi.org/10.5194/bg-20-2499-2023, 2023
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Nitrogen (N) is essential for life; thus, its availability plays a key role in determining marine productivity. Using incubations of seawater spiked with a rare form of N measurable on a mass spectrometer, we quantified microbial pathways that determine marine N availability. The results show that pathways that recycle N have higher rates than those that result in its loss from biomass and present new evidence for anaerobic nitrite oxidation, a process long thought to be strictly aerobic.
Amanda Gerotto, Hongrui Zhang, Renata Hanae Nagai, Heather M. Stoll, Rubens César Lopes Figueira, Chuanlian Liu, and Iván Hernández-Almeida
Biogeosciences, 20, 1725–1739, https://doi.org/10.5194/bg-20-1725-2023, https://doi.org/10.5194/bg-20-1725-2023, 2023
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Based on the analysis of the response of coccolithophores’ morphological attributes in a laboratory dissolution experiment and surface sediment samples from the South China Sea, we proposed that the thickness shape (ks) factor of fossil coccoliths together with the normalized ks variation, which is the ratio of the standard deviation of ks (σ) over the mean ks (σ/ks), is a robust and novel proxy to reconstruct past changes in deep ocean carbon chemistry.
Katherine E. Turner, Doug M. Smith, Anna Katavouta, and Richard G. Williams
Biogeosciences, 20, 1671–1690, https://doi.org/10.5194/bg-20-1671-2023, https://doi.org/10.5194/bg-20-1671-2023, 2023
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We present a new method for reconstructing ocean carbon using climate models and temperature and salinity observations. To test this method, we reconstruct modelled carbon using synthetic observations consistent with current sampling programmes. Sensitivity tests show skill in reconstructing carbon trends and variability within the upper 2000 m. Our results indicate that this method can be used for a new global estimate for ocean carbon content.
Alexandre Mignot, Hervé Claustre, Gianpiero Cossarini, Fabrizio D'Ortenzio, Elodie Gutknecht, Julien Lamouroux, Paolo Lazzari, Coralie Perruche, Stefano Salon, Raphaëlle Sauzède, Vincent Taillandier, and Anna Teruzzi
Biogeosciences, 20, 1405–1422, https://doi.org/10.5194/bg-20-1405-2023, https://doi.org/10.5194/bg-20-1405-2023, 2023
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Numerical models of ocean biogeochemistry are becoming a major tool to detect and predict the impact of climate change on marine resources and monitor ocean health. Here, we demonstrate the use of the global array of BGC-Argo floats for the assessment of biogeochemical models. We first detail the handling of the BGC-Argo data set for model assessment purposes. We then present 23 assessment metrics to quantify the consistency of BGC model simulations with respect to BGC-Argo data.
Alban Planchat, Lester Kwiatkowski, Laurent Bopp, Olivier Torres, James R. Christian, Momme Butenschön, Tomas Lovato, Roland Séférian, Matthew A. Chamberlain, Olivier Aumont, Michio Watanabe, Akitomo Yamamoto, Andrew Yool, Tatiana Ilyina, Hiroyuki Tsujino, Kristen M. Krumhardt, Jörg Schwinger, Jerry Tjiputra, John P. Dunne, and Charles Stock
Biogeosciences, 20, 1195–1257, https://doi.org/10.5194/bg-20-1195-2023, https://doi.org/10.5194/bg-20-1195-2023, 2023
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Ocean alkalinity is critical to the uptake of atmospheric carbon and acidification in surface waters. We review the representation of alkalinity and the associated calcium carbonate cycle in Earth system models. While many parameterizations remain present in the latest generation of models, there is a general improvement in the simulated alkalinity distribution. This improvement is related to an increase in the export of biotic calcium carbonate, which closer resembles observations.
Jérôme Pinti, Tim DeVries, Tommy Norin, Camila Serra-Pompei, Roland Proud, David A. Siegel, Thomas Kiørboe, Colleen M. Petrik, Ken H. Andersen, Andrew S. Brierley, and André W. Visser
Biogeosciences, 20, 997–1009, https://doi.org/10.5194/bg-20-997-2023, https://doi.org/10.5194/bg-20-997-2023, 2023
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Large numbers of marine organisms such as zooplankton and fish perform daily vertical migration between the surface (at night) and the depths (in the daytime). This fascinating migration is important for the carbon cycle, as these organisms actively bring carbon to depths where it is stored away from the atmosphere for a long time. Here, we quantify the contributions of different animals to this carbon drawdown and storage and show that fish are important to the biological carbon pump.
Alastair J. M. Lough, Alessandro Tagliabue, Clément Demasy, Joseph A. Resing, Travis Mellett, Neil J. Wyatt, and Maeve C. Lohan
Biogeosciences, 20, 405–420, https://doi.org/10.5194/bg-20-405-2023, https://doi.org/10.5194/bg-20-405-2023, 2023
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Iron is a key nutrient for ocean primary productivity. Hydrothermal vents are a source of iron to the oceans, but the size of this source is poorly understood. This study examines the variability in iron inputs between hydrothermal vents in different geological settings. The vents studied release different amounts of Fe, resulting in plumes with similar dissolved iron concentrations but different particulate concentrations. This will help to refine modelling of iron-limited ocean productivity.
Nicole M. Travis, Colette L. Kelly, Margaret R. Mulholland, and Karen L. Casciotti
Biogeosciences, 20, 325–347, https://doi.org/10.5194/bg-20-325-2023, https://doi.org/10.5194/bg-20-325-2023, 2023
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The primary nitrite maximum is a ubiquitous upper ocean feature where nitrite accumulates, but we still do not understand its formation and the co-occurring microbial processes involved. Using correlative methods and rates measurements, we found strong spatial patterns between environmental conditions and depths of the nitrite maxima, but not the maximum concentrations. Nitrification was the dominant source of nitrite, with occasional high nitrite production from phytoplankton near the coast.
Natacha Le Grix, Jakob Zscheischler, Keith B. Rodgers, Ryohei Yamaguchi, and Thomas L. Frölicher
Biogeosciences, 19, 5807–5835, https://doi.org/10.5194/bg-19-5807-2022, https://doi.org/10.5194/bg-19-5807-2022, 2022
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Compound events threaten marine ecosystems. Here, we investigate the potentially harmful combination of marine heatwaves with low phytoplankton productivity. Using satellite-based observations, we show that these compound events are frequent in the low latitudes. We then investigate the drivers of these compound events using Earth system models. The models share similar drivers in the low latitudes but disagree in the high latitudes due to divergent factors limiting phytoplankton production.
Abigale M. Wyatt, Laure Resplandy, and Adrian Marchetti
Biogeosciences, 19, 5689–5705, https://doi.org/10.5194/bg-19-5689-2022, https://doi.org/10.5194/bg-19-5689-2022, 2022
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Marine heat waves (MHWs) are a frequent event in the northeast Pacific, with a large impact on the region's ecosystems. Large phytoplankton in the North Pacific Transition Zone are greatly affected by decreased nutrients, with less of an impact in the Alaskan Gyre. For small phytoplankton, MHWs increase the spring small phytoplankton population in both regions thanks to reduced light limitation. In both zones, this results in a significant decrease in the ratio of large to small phytoplankton.
Margot C. F. Debyser, Laetitia Pichevin, Robyn E. Tuerena, Paul A. Dodd, Antonia Doncila, and Raja S. Ganeshram
Biogeosciences, 19, 5499–5520, https://doi.org/10.5194/bg-19-5499-2022, https://doi.org/10.5194/bg-19-5499-2022, 2022
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We focus on the exchange of key nutrients for algae production between the Arctic and Atlantic oceans through the Fram Strait. We show that the export of dissolved silicon here is controlled by the availability of nitrate which is influenced by denitrification on Arctic shelves. We suggest that any future changes in the river inputs of silica and changes in denitrification due to climate change will impact the amount of silicon exported, with impacts on Atlantic algal productivity and ecology.
Emily J. Zakem, Barbara Bayer, Wei Qin, Alyson E. Santoro, Yao Zhang, and Naomi M. Levine
Biogeosciences, 19, 5401–5418, https://doi.org/10.5194/bg-19-5401-2022, https://doi.org/10.5194/bg-19-5401-2022, 2022
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We use a microbial ecosystem model to quantitatively explain the mechanisms controlling observed relative abundances and nitrification rates of ammonia- and nitrite-oxidizing microorganisms in the ocean. We also estimate how much global carbon fixation can be associated with chemoautotrophic nitrification. Our results improve our understanding of the controls on nitrification, laying the groundwork for more accurate predictions in global climate models.
Cited articles
Aminot, A. and Kerouel, R.: Dosage automatique des nutriments dans les eaux
marines méthodes en flux continu, in: Méthodes d'analyse en milieu
marin, Ifremer Editions, 25, Quae, 2007.
Argo: Argo float data and metadata from Global Data Assembly Centre (Argo GDAC), SEANOE, https://doi.org/10.17882/42182, 2020.
Astraldi, M. and Gasparini, G. P.: The seasonal characteristics of the
circulation in the Tyrrhenian Sea, in: The seasonal and interannual
variability of the western Mediterranean Sea, edited by: La Violette, P. E.,
Coastal and Estuarine Studies, Agu, Washington, 46, 115–134, 1994.
Astraldi, M., Conversano, F., Civitarese, G., Gasparini, G. P., Ribera
d'Alcalà, M., and Vetrano, A.: Water mass properties and chemical
signatures in the central Mediterranean region, J. Marine Syst.,
33, 155–177, 2002.
Barbieux, M., Uitz, J., Gentili, B., Pasqueron de Fommervault, O., Mignot, A., Poteau, A., Schmechtig, C., Taillandier, V., Leymarie, E., Penkerc'h, C., D'Ortenzio, F., Claustre, H., and Bricaud, A.: Bio-optical characterization of subsurface chlorophyll maxima in the Mediterranean Sea from a Biogeochemical-Argo float database, Biogeosciences, 16, 1321–1342, https://doi.org/10.5194/bg-16-1321-2019, 2019.
Béthoux, J.-P.: Oxygen consumption, new production, vertical advection
and environmental evolution in the Mediterranean Sea, Deep-Sea Res., 36,
769–781, 1989.
Béthoux, J. P., Morin, P., Chaumery, C., Connan, O., Gentili, B., and
Ruiz-Pino, D.: Nutrients in the Mediterranean Sea, mass balance and
statistical analysis of concentrations with respect to environmental change,
Mar. Chem., 63, 155–169, 1998.
Biogeochemical-Argo Planning Group: The Scientific Rationale, Design and
Implementation Plan for a Biogeochemical-Argo Float Array (Report),
Issy-les-Moulineaux, Ifremer, 2016.
Bouffard, D. and Boegman, L: A diapycnal diffusivity model for stratified
environmental flows, Dynam. Atmos. Oceans, 61–62, 14–34, 2013.
Bryden, H., Schroeder, K., Sparnocchia, S., Borghini, M., and Vetrano, A.:
Thermohaline staircases in the western Mediterranean Sea, J. Mar.
Res., 72, 1–18, 2014.
Buffett, G. G., Krahmann, G., Klaeschen, D., Schroeder, K., Sallarès, V.,
Papenberg, C., Ranero, C. R., and Zitellini, N.: Seismic oceanography in the
Tyrrhenian Sea: thermohaline staircases, eddies, and internal waves, J.
Geophys. Res., 122, 8503–8523, https://doi.org/10.1002/2017JC012726, 2017.
Cotroneo, Y., Aulicino, G., Ruiz, S., Sánchez Román, A., Torner Tomàs, M., Pascual, A., Fusco, G., Heslop, E., Tintoré, J., and Budillon, G.: Glider data collected during the Algerian Basin Circulation Unmanned Survey, Earth Syst. Sci. Data, 11, 147–161, https://doi.org/10.5194/essd-11-147-2019, 2019.
Cuypers, Y., Bouruet-Aubertot, P., Marec, C., and Fuda, J.-L.: Characterization of turbulence from a fine-scale parameterization and microstructure measurements in the Mediterranean Sea during the BOUM experiment, Biogeosciences, 9, 3131–3149, https://doi.org/10.5194/bg-9-3131-2012, 2012.
Dillon, T. M.: Vertical overturns: a comparison of Thorpe and Ozmidov length
scales, J. Geophys. Res., 87, 9601–9613, 1982.
D'Ortenzio, F. and Ribera d'Alcalà, M.: On the trophic regimes of the Mediterranean Sea: a satellite analysis, Biogeosciences, 6, 139–148, https://doi.org/10.5194/bg-6-139-2009, 2009.
D'Ortenzio F., Taillandier, V., Claustre, H., Prieur, L., Leymarie, E.,
Mignot, A., Poteau, A., Penkerc'h, C., and Schmechtig, C.: Biogeochemical
Argo: the test case of the NAOS Mediterranean array, Front. Mar.
Sci., 7, 120, https://doi.org/10.3389/fmars.2020.00120, 2020.
Durante, S., Schroeder, K., Mazzei, L., Pierini, S., Borghini, M., and
Sparnocchia, S.: Permanent thermohaline staircases in the Tyrrhenian Sea,
Geophys. Res. Lett., 46, 1562–1570, 2019.
Falco, P., Trani, M., and Zambianchi, E.: Water mass structure and deep
mixing processes in the Tyrrhenian Sea: results from the VECTOR project,
Deep-Sea Res. Pt. I, 113, 7–21, 2016.
Fernandez-Castro, B., Mourino-Carballido, B., Maranon, E., Choucino, P.,
Gago, J., Ramirez, T., Vidal, M., Bode, A., Blasco, D., Royer, S. J.,
Estrada, M., and Simo, R.: Importance of salt fingering for new nitrogen
supply in the oligotrophic ocean, Nat. Commun., 6, 8002, https://doi.org/10.1038/ncomms9002, 2015.
Ferron, B., Bouruet Aubertot, P., Cuypers, Y., Schroeder, K., and Borghini,
M.: How important are diapycnal mixing and geothermal heating for the deep
circulation of the Western Mediterranean?, Geophys. Res. Lett., 44,
7845–7854, 2017.
Gasparini, G. P., Ortona, A., Budillon, G., Astraldi, M., and Sansone, E.:
The effect of the Eastern Mediterranean Transient on the hydrographic
characteristics in the strait of Sicily and in the Tyrrhenian Sea, Deep-Sea
Res. Pt. I, 52, 915–935, 2005.
Guieu, C. and Desboeufs, K.: PEACETIME cruise, RV Pourquoi Pas?, LEFE CYBER Database (PROOF/DataBase/CS),
https://doi.org/10.17600/17000300, 2017.
Guieu, C., D'Ortenzio, F., Dulac, F., Taillandier, V., Doglioli, A., Petrenko, A., Barrillon, S., Mallet, M., Nabat, P., and Desboeufs, K.: Process studies at the air-sea interface after atmospheric deposition in the Mediterranean Sea: objectives and strategy of the PEACETIME oceanographic campaign (May–June 2017), Biogeosciences Discuss., https://doi.org/10.5194/bg-2020-44, in review, 2020.
Hamilton, J. M., Lewis, M. R., and Ruddick, B. R.: Vertical fluxes of nitrate
associated with salt fingers in the world's oceans, J. Geophys.
Res., 94, 2137–2145, 1989.
Jambu, M.: Fortran IV computer program for rapid hierarchical classification
of large data sets, Comput. Geosci., 7, 297–310, 1981.
Johnson, K. S. and Coletti, L. J.: In situ ultraviolet spectrophotometry
for high resolution and long-term monitoring of nitrate, bromide and
bisulfide in the ocean, Deep-Sea Res. Pt. I, 49, 1291–1305, 2002.
Keraghel, M., Louanchi, F., Zerrouki, M., Ait Kaci, M., Aït-Ameur, N., Labaste, M., Legoff, H., Taillandier, V., Harid, R., and
Mortier, L.: Carbonate system properties and anthropogenic carbon inventory
in the Algerian Basin during SOMBA cruise (2014): acidification rate
estimate, Mar. Chem., 221, 103783, https://doi.org/10.1016/j.marchem.2020.103783, 2020.
Krahmann, G.: Horizontal variability of thermohaline staircases in the
western Mediterranean, Double-Diffusive Processes, 1996 Summer Study Program
in: Geophysical Fluid Dynamics, edited by: Meacham, S. and Tucholke, D., Woods Hole
Oceanographic Institution, Technical Report WHOI-97-10, 331–347, 1997.
Kress, N., Manca, B. B., Klein, B., and Deponte, D.: Continuing influence of
the changed thermohaline circulation in the eastern Mediterranean on the
distribution of dissolved oxygen and nutrients: Physical and chemical
characterization of the water masses, J. Geophys. Res.-Oceans, 108, 8109, https://doi.org/10.1029/2002JC001397, 2003.
Krivosheya, V. G. and Ovchinnikov, I. M.: Pecularities in the geostrophic
circulation of the waters of the Tyrrhenian Sea, Oceanology, 13, 822–827,
1973.
Large, W. G., McWilliams, J. C., and Doney, S. C.: Oceanic vertical mixing: a
review and a model with a nonlocal boundary layer parameterization, Rev.
Geophys., 32, 363–403, 1994.
Lascaratos, A., Roether, W., Nittis, K., and Klein, B.: Recent changes in
deep water formation and spreading in the eastern Mediterranean Sea: a
review, Prog. Oceanogr., 44, 5–36, 1999.
Lavigne, H., D'Ortenzio, F., Migon, C., Claustre, H., Testor, P., Ribera
d'Alcalà, M., Lavezza, R., Houpert, L., and Prieur, L.: Enhancing the
comprehension of mixed layer depth control on the Mediterranean
phytoplankton phenology, J. Geophys. Res., 118, 3416–3430,
2013.
Mallil, K., Testor, P., Le Goff, H., Mortier, L., Taillandier, V., Ait
Ameur, N., Louanchi, F., and Labaste, M.: Hydrologie et circulation
océanique dans le gyre est et ouest du bassin Algérien, Rapport de
la Commission Internationale de la Mer Méditerranée, 41, 86, 2016.
McDougall, T. J.: Double-diffusive interleaving. Part II: finite amplitude,
steady state interleaving, J. Phys. Oceanogr., 15, 1542–1556,
1985.
MEDOC Group: Observation of Formation of Deep Water in the Mediterranean
Sea, 1969, Nature, 227, 1037, https://doi.org/10.1038/2271037a0, 1970.
Merryfield, W. J.: Origin of thermohaline staircases, J. Phys.
Oceanogr., 30, 1046–1068, 2000.
Molcard, R. and Tait, R. I.: The steady state of the step structure in the
Tyrrhenian Sea, In: A voyage of discovery: George Deacon seventieth
anniversary volume, edited by: Angel, M., Pergamon Press, New York, 221–233,
1977.
Morel, A. and André, J. M.: Pigment distribution and primary production
in the western Mediterranean as derived and modeled from coastal zone color
scanner observations, J. Geophys. Res.-Oceans, 96,
12685–12698, 1991.
Mortier, L., Aït Ameur, N., and Taillandier, V.: SOMBA-GE-2014 cruise,
RV Téthys II, https://doi.org/10.17600/14007500, 2014.
Mouriño-Carballido, B., Hojas, E., Cermeño, P., Chouciño, P.,
Fernández-Castro, B., Latasa, M., Marañón, E., Morán,
X. A. G., and Vidal, M.: Nutrient supply controls picoplankton community
structure during three contrasting seasons in the northwestern Mediterranean
Sea, Mar. Ecol.-Prog. Ser., 543, 1–19, 2016.
Nittis, K. and Lascaratos, A.: Intermediate water formation in the
Levantine Sea: the response to interannual variability of atmospheric
forcing, in: The eastern Mediterranean as a laboratory basin for the
assessment of contrasting ecosystems, Springer, Dordrecht,
441–446, 1999.
Omand, M. M. and Mahadevan, A.: The shape of the oceanic nitracline, Biogeosciences, 12, 3273–3287, https://doi.org/10.5194/bg-12-3273-2015, 2015.
Onken, R. and Brembilla E.: Double diffusion in the Mediterranean Sea:
observation and parameterization of salt finger convection, J.
Geophys. Res., 108, 8124, https://doi.org/10.1029/2002JC001349, 2003.
Osborn, T. R.: Estimates of local rate of vertical diffusion from dissipation
measurements, J. Phys. Oceanogr., 10, 83–89, 1980.
Park, Y.-H., Lee, J.-H., Durand, I., and Hong, C.-S.: Validation of Thorpe-scale-derived vertical diffusivities against microstructure measurements in the Kerguelen region, Biogeosciences, 11, 6927–6937, https://doi.org/10.5194/bg-11-6927-2014, 2014.
Pasqueron de Fommervault, O., D'Ortenzio, F., Mangin, M., Serra, R., Migon,
C., Claustre, H., Lavigne, H., Ribera d'Alcalà, M., Prieur, L.,
Taillandier, V., Schmechtig, C., Poteau, A., Leymarie, E., Besson, F., and
Obolensky, G.: Seasonal variability of nutrient concentrations in the
Mediterranean Sea: Contribution of Bio-Argo floats, J. Geophys.
Res.-Oceans, 120, https://doi.org/10.1002/2015JC011103, 2015.
Poulain, P.-M., Barbanti, R., Font, J., Cruzado, A., Millot, C., Gertman, I., Griffa, A., Molcard, A., Rupolo, V., Le Bras, S., and Petit de la Villeon, L.: MedArgo: a drifting profiler program in the Mediterranean Sea, Ocean Sci., 3, 379–395, https://doi.org/10.5194/os-3-379-2007, 2007.
Prieur, L., Béthoux, J. P., Bong, J. H., and Taillez, D.:
Particularités hydrologiques et formation d'eau profonde dans le bassin
Liguro-Provençal en 1981–1982, Rapport de la Commission Internationale
de la Mer Méditerranée, 28, 51–53, 1983.
Pujo-Pay, M., Conan, P., Oriol, L., Cornet-Barthaux, V., Falco, C., Ghiglione, J.-F., Goyet, C., Moutin, T., and Prieur, L.: Integrated survey of elemental stoichiometry (C, N, P) from the western to eastern Mediterranean Sea, Biogeosciences, 8, 883–899, https://doi.org/10.5194/bg-8-883-2011, 2011.
Radko, T.: What determines the thickness of layers in a thermohaline
staircase?, J. Fluid Mech., 523, 79–98, 2005.
Radko, T. and Smith, D. P.: Equilibrium transport in double-diffusive
convection, J. Fluid Mech., 692, 5–27, 2012.
Radko, T., Flanagan, J. D., Stellmach, S., and Timmermans, M. L.:
Double-diffusive recipes. Part 2: Layer-merging events, J. Phys.
Oceanogr., 44, 1285–1305, 2014.
Ribera d'Alcalà, M., Civitarese, G., Conversano, F., and Lavezza, R.:
Nutrient ratios and fluxes hint at overlooked processes in the Mediterranean
Sea, J. Geophys. Res.-Oceans, 108, 8106, https://doi.org/10.1029/2002JC001650, 2003.
Roether, W., Klein, B., Manca, B. B., Theocharis, A., and Kioroglou, S.:
Transient Eastern Mediterranean deep waters in response to the massive
dense-water output of the Aegean Sea in the 1990s, Prog. Oceanogr.,
74, 540–571, 2007.
Sakamoto, C. M., Johnson, K. S., and Coletti, L. J.: Improved algorithm for
the computation of nitrate concentrations in sea- water using an in situ
ultraviolet spectrophotometer, Limnol. Oceanogr.-Meth., 7,
132–143, 2009.
Santinelli, C., Iacono, R., Napolitano, E., and Ribera d'Alcalá, M.: Surface transport of DOC acts as a trophic link among Mediterranean sub-basins, Biogeosciences Discuss., https://doi.org/10.5194/bg-2018-418, 2018.
Schmitt, R. W.: Form of the temperature-salinity relationship in the Central
Water: evidence for double-diffusive mixing, J. Phys.
Oceanogr., 11, 1015–1026, 1981.
Schmitt, R. W.: Double diffusion in oceanography, Annu. Rev. Fluid
Mech., 26, 255–285, 1994.
Schmitt, R. W., Perkins, H., Boyd, J. D., and Stalcup, C.: C-SALT: an
investigation of the thermohaline staircase in the western tropical North
Atlantic, Deep-Sea Res., 34, 1655–1665, 1987.
Send, U. and Testor, P.: Direct observations reveal the deep circulation of
the western Mediterranean Sea, J. Geophys. Res.-Oceans, 122, 10091–10098, https://doi.org/10.1002/2016JC012679,
2017.
Sparnocchia, S., Gasparini, G. P., Astraldi, M., Borghini, M., and Pistek,
P.: Dynamics and mixing of the Eastern Mediterranean outflow in the
Tyrrhenian basin, J. Mar. Syst., 20, 301–317, 1999.
Stern, M. E.: The “Salt-Fountain” and Thermohaline Convection, Tellus,
12, 172–175, 1960.
Stern, M. E. and Turner, J. S.: Salt fingers and convecting layers, Deep-Sea
Res., 16, 497–511, 1969.
Taillandier, V., Wagener, T., D'Ortenzio, F., Mayot, N., Legoff, H., Ras, J., Coppola, L., Pasqueron de Fommervault, O., Schmechtig, C., Diamond, E., Bittig, H., Lefevre, D., Leymarie, E., Poteau, A., and Prieur, L.: Hydrography and biogeochemistry dedicated to the Mediterranean BGC-Argo network during a cruise with RV Tethys 2 in May 2015, Earth Syst. Sci. Data, 10, 627–641, https://doi.org/10.5194/essd-10-627-2018, 2018.
Testor, P. and Gascard, J. C.: Large scale flow separation and mesoscale
eddy formation in the Algerian Basin, Prog. Oceanogr., 66,
211–230, 2005.
Testor, P., Send, U., Gascard, J. C., Millot, C., Taupier-Letage, I., and
Beranger, K.: The mean circulation of the southwestern Mediterranean Sea:
Algerian Gyres, J. Geophys. Res., 110, C110017, https://doi.org/10.1029/2004JC002861, 2005.
Testor, P., Le Goff, H., Labaste, M., Coppola, L., Mortier, L., Taillandier,
V., Dausse, D., Kunesch, S., Diamond-Riquier, E., Garcia, N., Durrieu de
Madron, X., and Raimbault, P.: MOOSE-GE, https://doi.org/10.18142/235, 2010.
The LIWEX Group: Levantine
basin – A laboratory for multiple water mass formation processes, J. Geophys. Res., 108,
8101, https://doi.org/10.1029/2002JC001643, 2003.
Williams, R. G. and Follows, M. J.: Physical transport of nutrients and the
maintenance of biological production, in: Ocean
Biogeochemistry, edited by: Fasham, M. J. R., Global Change – The IGBP Series, Springer, Berlin,
Heidelberg, 2003.
Wong, A., Keeley, R., Carval, T., and the Argo Data Management Team: Argo
Quality Control Manual for CTD and Trajectory Data, https://doi.org/10.13155/33951,
2019.
Wüst, G.: On the vertical circulation of the Mediterranean Sea, J.
Geophys. Res., 66, 3261–3271, 1961.
Ziveri, P. and Grelaud, M.: Physical oceanography during Ángeles
Alvariño cruise MedSeA2013, Universitat Autònoma de Barcelona,
PANGAEA, https://doi.org/10.1594/PANGAEA.846067, 2015.
Zodiatis, G. and Gasparini, G. P.: Thermohaline staircase formations in the
Tyrrhenian Sea, Deep-Sea Res. Pt. I, 43, 655–678, 1996.
Zunino, P., Schroeder, K., Vargas-Yáñez, M., Gasparini, G. P.,
Coppola, L., García-Martínez, M. C., and Moya-Ruiz, F.: Effects of
the Western Mediterranean Transition on the resident water masses: pure
warming, pure freshening and pure heaving, J. Mar. Syst., 96–97,
15–23, 2012.
Short summary
This study addresses the role played by vertical diffusion in the nutrient enrichment of the Levantine intermediate waters, a process particularly relevant inside thermohaline staircases. Thanks to a high profiling frequency over a 4-year period, BGC-Argo float observations reveal the temporal continuity of the layering patterns encountered during the cruise PEACETIME and their impact on vertical and lateral transfers of nitrate between the deep reservoir and the surface productive zone.
This study addresses the role played by vertical diffusion in the nutrient enrichment of the...
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