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1. Nudibranch predation boosts sponge silicon cycling

Author: María López-Acosta, Clémence Potel, Morgane Gallinari, Fiz F. Pérez, and Aude Leynaert
Subjects: Medicine, Science
Abstract: Abstract Diatoms play a key role in the marine silica cycle, but recent studies have shown that sponges can also have an important effect on this dynamic. They accumulate large stocks of biogenic silica within their bodies over long periods, which are thought to vary little on an intra-annual scale. The observation of an abrupt decline in sponge biomass in parallel with large increases in abundance of a spongivorous nudibranch (Doris verrucosa) led us to conduct a year-long study on the effect of nudibranch predation on the silicon budget of a sponge (Hymeniacidon perlevis) population. After 5 months of predation, the abundance of sponge individuals did not change but their biomass decreased by 95%, of which 48% was explained by nudibranch predation. About 97% of sponge spicules ingested by nudibranchs while feeding was excreted, most of them unbroken, implying a high rate of sponge silica deposition in the surrounding sediments. After predation, sponges partially recovered their biomass stocks within 7 months. This involved a rapid growth rate and large assimilation of dissolved silicon. Surprisingly, the highest rates of silicon absorption occurred when dissolved silicon concentration in seawater was minimal (
Published: 2023
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2. Revisiting the biogenic silica burial flux determinations: A case study for the East China seas

Author: Dongdong Zhu, Jill N. Sutton, Aude Leynaert, Paul J. Tréguer, Jonas Schoelynck, Morgane Gallinari, Yuwei Ma, and Su Mei Liu
Subjects: biogenic silica, alkaline digestion, analytical methods, burial flux, coastal and continental margin zones, East China seas, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: The Coastal and Continental Margin Zones (CCMZs) contribute to 40% of the total burial flux of biogenic silica (bSi) of the world ocean. However, the accurate determination of the bSi content (bSiO2%) in marine sediments remains a challenge. The alkaline methods commonly used to quantitatively determine bSiO2% can completely digest the amorphous silica of diatoms but are less effective at digesting radiolarians and sponge spicules. In addition, the lithogenic silica (lSi) found in sediments is partly digested during these alkaline extractions, which can bias the accuracy of the determined bSiO2%. This is of importance in CCMZs where the lSi:bSi ratio is high. In this study, we examined sediments collected in the CCMZs of East China seas, an environment of peculiar interest given the large amount of lSi deposited by the Yellow River and the Yangtze River. The results show that alkaline digestions using stronger solutions and pretreatment steps resulted in an overestimate of the bSiO2% due to increased leaching of silica mainly from authigenic silicates and clays, whereas weak digestions underestimated the bSiO2% owing to incomplete digestion of sponge spicules. We found that the use of the Si/Al method accurately corrects for the lSi fraction in marine sediments, and thereby improves the determinations of bSiO2% in the sediments of East China seas CCMZs. Ensuring full digestion of all bSi remains challenging, in particular for sponge spicules, motivating both verifications via microscopy and longer extraction times. To emphasize the influence of these methodological differences, we revised the bSi burial flux in the East China seas and provide a new estimate of 253 (± 286) Gmol-SiO2 yr-1, which is one third of the previous estimates. We discuss the potential contribution from radiolarian and sponges and we propose a new general protocol for the determination of bSi in sediments that minimizes the methodological bias in bSi determination.
Published: 2023
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3. Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea

Author: Vesselin M. Dekov, Valentina Y. Darakchieva, Kjell Billström, C. Dieter Garbe-Schönberg, George D. Kamenov, Morgane Gallinari, Lyubomir Dimitrov, Olivier Ragueneau, and Ellen Kooijman
Subjects: Oceanography, GC1-1581
Abstract: Summary: Concentrations of a large set of major and trace elements, and Sr, Nd and Pb isotope ratios were measured in Holocene sediments cored in the western deep Black Sea in order to unravel: (1) the controls of element enrichment, and (2) sources of the detrital component. The transition of the basin from oxic to euxinic resulted in enrichment or depletion in a number of elements in the deep-sea sediments. Authigenic Fe enrichment appears to depend on the amount of Fe mobilized from the sediment through the benthic redox shuttle mechanism and free H2S in the water column (degree of “euxinization”). Manganese enrichment is controlled by diagenetic reactions within the sediment: the dissolution of Mn minerals, Mn2+ diffusion upward and reprecipitation. Barium enrichment is also controlled by diagenetic reactions, sulfate reduction and methanogenesis, that take place above and below the sulfate-methane transition, respectively. The major part of V, Co, Ni, Cu, Zn, Cr, Mo, Cd and Sb is inferred to have co-precipitated with Fe in the euxinic deep waters and to have been incorporated into authigenic Fe-sulfides. Basin reservoir effect additionally influences the Mo enrichment. The U enrichment is interpreted to have a different origin in the two organic-rich stratigraphic units (II and I). It is inferred to be: (i) at the expense of the U inventory of the deepwater pool and a result of inorganic reduction of U at euxinic conditions in the lower Unit II; and (ii) at the expense of the U inventory of the surface water pool and a result of biogenic uptake and transfer to the sediment by the plankton in the upper Unit I. The high field strength elements are closely linked to the detrital component and their depletion in the organic-rich sediments reflects a dilution of the detrital component by the biogenic one. The enrichments of REE, Sn and Th are likely controlled by adsorption on clay minerals. Sr-Nd-Pb isotope compositions of the alumino-silicate component of the studied sediments are relatively uniform. They are most likely controlled by riverine suspended matter supplied mainly in the NW Black Sea (Danube Delta) and transported southward by marine currents, and to a lesser degree by suspended matter from the small rivers draining SE Bulgaria and NW Turkey. Wind-blown dust from the Sahara Desert appears to have a minor contribution to the alumino-silicate component of the sediments. The slight shift in the Pb isotopes in Unit I upper layers is possibly caused by the addition of anthropogenic Pb. Keywords: Anoxic, Black Sea, Element enrichment, Sr-Nd-Pb-isotopes, Holocene
Published: 2020
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4. Revisiting the distribution of oceanic N2 fixation and estimating diazotrophic contribution to marine production

Author: Weiyi Tang, Seaver Wang, Debany Fonseca-Batista, Frank Dehairs, Scott Gifford, Aridane G. Gonzalez, Morgane Gallinari, Hélène Planquette, Géraldine Sarthou, and Nicolas Cassar
Subjects: Science
Abstract: The geographical distribution and controlling factors of marine N2 fixation are understudied. Here the authors find increasing rates of N2 fixation from the Sargasso Sea to the coastal waters of North America, driven primarily by cyanobacterial diazotrophs and best correlated with phosphorus availability and chlorophyll-a concentrations.
Published: 2019
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5. Copepods Boost the Production but Reduce the Carbon Export Efficiency by Diatoms

Author: Brivaëla Moriceau, Morten H. Iversen, Morgane Gallinari, Antti-Jussi O. Evertsen, Manon Le Goff, Beatriz Beker, Julia Boutorh, Rudolph Corvaisier, Nathalie Coffineau, Anne Donval, Sarah L. C. Giering, Marja Koski, Christophe Lambert, Richard S. Lampitt, Alain Le Mercier, Annick Masson, Herwig Stibor, Maria Stockenreiter, and Christina L. De La Rocha
Subjects: biogenic silica, POC, marine snow, zooplankton, mesocosm, Bay of Hopavågen, Science, General. Including nature conservation, geographical distribution, QH1-199.5
Abstract: The fraction of net primary production that is exported from the euphotic zone as sinking particulate organic carbon (POC) varies notably through time and from region to region. Phytoplankton containing biominerals, such as silicified diatoms have long been associated with high export fluxes. However, recent reviews point out that the magnitude of export is not controlled by diatoms alone, but determined by the whole plankton community structure. The combined effect of phytoplankton community composition and zooplankton abundance on export flux dynamics, were explored using a set of 12 large outdoor mesocosms. All mesocosms received a daily addition of minor amounts of nitrate and phosphate, while only 6 mesocosms received silicic acid (dSi). This resulted in a dominance of diatoms and dinoflagellate in the +Si mesocosms and a dominance of dinoflagellate in the −Si mesocosms. Simultaneously, half of the mesocosms had decreased mesozooplankton populations whereas the other half were supplemented with additional zooplankton. In all mesocosms, POC fluxes were positively correlated to Si/C ratios measured in the surface community and additions of dSi globally increased the export fluxes in all treatments highlighting the role of diatoms in C export. The presence of additional copepods resulted in higher standing stocks of POC, most probably through trophic cascades. However it only resulted in higher export fluxes for the −Si mesocosms. In the +Si with copepod addition (+Si +Cops) export was dominated by large diatoms with higher Si/C ratios in sinking material than in standing stocks. During non-bloom situations, the grazing activity of copepods decrease the export efficiency in diatom dominated systems by changing the structure of the phytoplankton community and/or preventing their aggregation. However, in flagellate-dominated system, the copepods increased phytoplankton growth, aggregation and fecal pellet production, with overall higher net export not always visible in term of export efficiency.
Published: 2018
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6. HIPPO environmental monitoring: Impact of phytoplankton dynamics on water column chemistry and the sclerochronology of the king scallop (Pecten maximus) as a biogenic archive for past primary production reconstructions

Author: Valentin Siebert, Brivaëla Moriceau, Lukas Fröhlich, Bernd R. Schöne, Erwan Amice, Beatriz Beker, Kevin Bihannic, Isabelle Bihannic, Gaspard Delebecq, Jérémy Devesa, Morgane Gallinari, Yoan Germain, Émilie Grossteffan, Klaus Peter Jochum, Thierry Le Bec, Manon Le Goff, Céline Liorzou, Aude Leynaert, Claudie Marec, Marc Picheral, Peggy Rimmelin-Maury, Marie-Laure Rouget, Matthieu Waeles, and Julien Thébault
Abstract: As part of the HIPPO (HIgh-resolution Primary Production multi-prOxy archives) project, an environmental monitoring was carried out between March and October 2021 in the Bay of Brest. The aim of this survey was to better understand the processes which drive the incorporation of chemical elements into scallop shells and their links with phytoplankton dynamics. For this purpose, biological samples (scallops and phytoplankton) as well as water samples were collected in order to analyse various environmental parameters (element chemical properties, nutrients, chlorophyll, etc.). Here, some of the monitoring data are presented and discussed. The whole dataset is much larger and can potentially be very useful for other scientists performing sclerochronological investigations, studying biogeochemical cycles or conducting various ecological research projects.
Published: 2023
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7. Particulate Trace Element Export in the North Atlantic (GEOTRACES GA01 Transect, GEOVIDE Cruise)

Author: Maxi Castrillejo, Frank Dehairs, Nolwenn Lemaitre, Catherine Jeandel, Morgane Gallinari, Frédéric Planchon, Hélène Planquette, Stephane Roig, Géraldine Sarthou, Institute of Geochemistry and Petrology [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS), Laboratory of Ion Beam Physics, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), ANR-12-PDOC-0025,BITMAP,Biodisponibilité du fer et des métaux traces dans les particules marines(2012), ANR-13-BS06-0014,GEOVIDE,GEOVIDE, Une étude internationale GEOTRACES le long de la section OVIDE en Atlantique Nord et en Mer du Labrador(2013), ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Ion Beam Physics [ETH Zürich], Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)
Subjects: multiple carrier phases, 0106 biological sciences, Atmospheric Science, 010504 meteorology & atmospheric sciences, Geotraces, export fluxes, Cruise, 01 natural sciences, Geochemistry and Petrology, 14. Life underwater, Transect, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ACL, 010604 marine biology & hydrobiology, Trace element, Biogeochemistry, Particulates, residence times, particulate trace elements, Trace (semiology), GEOTRACES, Oceanography, 13. Climate action, Space and Planetary Science, [SDE]Environmental Sciences, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology
Abstract: International audience; Vertical export of particulate trace elements (pTEs) is a critically underconstrained aspect of their biogeochemistry. Here, we combine elemental analyses on large (>53 μm) particles and 234Th measurements to determine downward export fluxes from the upper layers (40-110 m) of pTEs (Al, Cd, Co, Cu, Fe, Mn, Ni, P, Ti, V, Zn) and mineral phases (lithogenic, Fe-and Mn-oxides, calcium carbonate, and opal) in the North Atlantic along the GEOVIDE transect (Portugal-Greenland-Canada; GEOTRACES GA01 cruise). The role of lithogenic particles in controlling TE fluxes is obvious at proximity of the Iberian margin where the highest pTE export fluxes were estimated (up to 3912 μg/m2/d for pFe). However, high lithogenic and pTE fluxes are also observed up to 1700 km off this margin in the west European and Icelandic basins (up to 931 μg/m2/d for pFe). The lowest pTE export fluxes are determined in the Labrador Sea (as low as 501 μg/m2/d for pFe). High Mn-and Fe-oxide fluxes are estimated at the open ocean stations, suggesting that authigenic particles are an important vector of pTEs. All along the transect, biogenic particles also drive the pTE export fluxes, as shown by the similar pTE/POC ratios between exports and phytoplankton quotas. The shortest residence times (dissolved + particulate) are generally observed where lithogenic particles control the pTE fluxes (as low as 2 days for Fe) whereas pTEs seem to be longer retained when the contribution of biogenic particles become greater (residence times up to 147 days for Fe).
Published: 2020
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8. The Green Edge cruise: Understanding the onset, life and fate of the Arctic phytoplankton spring bloom

Author: Flavienne Bruyant, Rémi Amiraux, Marie-Pier Amyot, Philippe Archambault, Lise Artigue, Lucas Bardedo de Freitas, Guislain Bécu, Simon Bélanger, Pascaline Bourgain, Annick Bricaud, Etienne Brouard, Camille Brunet, Tonya Burgers, Danielle Caleb, Katrine Chalut, Hervé Clautre, Véronique Cornet-Barthaux, Pierre Coupel, Marine Cusa, Fanny Cusset, Laeticia Dadaglio, Marty Davelaar, Gabriele Deslongchamps, Céline Dimier, Julie Dinasquet, Dany Dumont, Brent Else, Igor Eulaers, Joannie Ferland, Gabrielle Filteau, Marie-Hélène Forget, Jérome Fort, Louis Fortier, Martí Galí-Tapías, Morgane Gallinari, Svend-Erik Garbus, Nicole Garcia, Catherine Gérikas Ribeiro, Colline Gombault, Priscilla Gourvil, Clémence Goyens, Cindy Grant, Pierre-Luc Grondin, Pascal Guillot, Sandrine Hillion, Rachel Hussher, Fabien Joux, Hannah Joy-Warren, Gabriel Joyal, David Kieber, Augustin Lafond, José Lagunas, Patrick Lajeunesse, Catherine Lalande, Jade Larivière, Florence Le Gall, Karine Leblanc, Mathieu Leblanc, Justine Legras, Keith Levesque, Kate-Marie Lewis, Edouard Leymarie, Aude Leynaert, Thomas Linkowski, Martine Lizotte, Adriana Lopes dos Santos, Claudie Marec, Dominique Marie, Guillaume Massé, Philippe Massicotte, Atsushi Matsuoka, Lisa Miller, Sharif Mirshak, Nathalie Morata, Brivaela Moriceau, Philippe-Israël Morin, Simon Morisset, Anders Mosbech, Alfonso Mucci, Gabrielle Nadaï, Christian Nozais, Ingrid Obernosterer, Timothe Paire, Christos Panagiotopoulos, Marie Parenteau, Noémie Pelletier, Marc Picheral, Bernard Quéguiner, Patrick Raimbault, Joséphine Ras, Eric Rehm, Llúcia Ribot Lacosta, Jean-François Rontani, Blanche Saint-Béat, Julie Sansoulet, Noé Sardet, Catherine Schmechtig, Antoine Sciandra, Richard Sempéré, Caroline Sévigny, Jordan Toullec, Margot Tragin, Jean-Eric Tremblay, Annie-Pier Trottier, Daniel Vaulot, Anda Vladoiu, Lei Xue, Gustavo Yunda-Guarin, and Marcel Babin
Abstract: The Green Edge project was designed to investigate the onset, life and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in arctic ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocean food chain, it is crucial to understand how changes in the arctic environment will affect it. Green Edge was a large multidisciplinary collaborative project bringing researchers and technicians from 28 different institutions in seven countries, together aiming at understanding these changes and their impacts into the future. The fieldwork for the Green Edge project took place over two years (2015 and 2016) and was carried out from both an ice-camp and a research vessel in the Baffin Bay, canadian arctic. This paper describes the sampling strategy and the data set obtained from the research cruise, which took place aboard the Canadian Coast Guard Ship (CCGS) Amundsen in spring 2016. The dataset is available at https://doi.org/10.17882/59892 (Massicotte et al., 2019a).
Published: 2022

9. The Green Edge cruise: investigating the marginal ice zone processes during late spring and early summer to understand the fate of the Arctic phytoplankton bloom

Author: Flavienne Bruyant, Rémi Amiraux, Marie-Pier Amyot, Philippe Archambault, Lise Artigue, Lucas Barbedo de Freitas, Guislain Bécu, Simon Bélanger, Pascaline Bourgain, Annick Bricaud, Etienne Brouard, Camille Brunet, Tonya Burgers, Danielle Caleb, Katrine Chalut, Hervé Claustre, Véronique Cornet-Barthaux, Pierre Coupel, Marine Cusa, Fanny Cusset, Laeticia Dadaglio, Marty Davelaar, Gabrièle Deslongchamps, Céline Dimier, Julie Dinasquet, Dany Dumont, Brent Else, Igor Eulaers, Joannie Ferland, Gabrielle Filteau, Marie-Hélène Forget, Jérome Fort, Louis Fortier, Martí Galí, Morgane Gallinari, Svend-Erik Garbus, Nicole Garcia, Catherine Gérikas Ribeiro, Colline Gombault, Priscilla Gourvil, Clémence Goyens, Cindy Grant, Pierre-Luc Grondin, Pascal Guillot, Sandrine Hillion, Rachel Hussherr, Fabien Joux, Hannah Joy-Warren, Gabriel Joyal, David Kieber, Augustin Lafond, José Lagunas, Patrick Lajeunesse, Catherine Lalande, Jade Larivière, Florence Le Gall, Karine Leblanc, Mathieu Leblanc, Justine Legras, Keith Lévesque, Kate-M. Lewis, Edouard Leymarie, Aude Leynaert, Thomas Linkowski, Martine Lizotte, Adriana Lopes dos Santos, Claudie Marec, Dominique Marie, Guillaume Massé, Philippe Massicotte, Atsushi Matsuoka, Lisa A. Miller, Sharif Mirshak, Nathalie Morata, Brivaela Moriceau, Philippe-Israël Morin, Simon Morisset, Anders Mosbech, Alfonso Mucci, Gabrielle Nadaï, Christian Nozais, Ingrid Obernosterer, Thimoté Paire, Christos Panagiotopoulos, Marie Parenteau, Noémie Pelletier, Marc Picheral, Bernard Quéguiner, Patrick Raimbault, Joséphine Ras, Eric Rehm, Llúcia Ribot Lacosta, Jean-François Rontani, Blanche Saint-Béat, Julie Sansoulet, Noé Sardet, Catherine Schmechtig, Antoine Sciandra, Richard Sempéré, Caroline Sévigny, Jordan Toullec, Margot Tragin, Jean-Éric Tremblay, Annie-Pier Trottier, Daniel Vaulot, Anda Vladoiu, Lei Xue, Gustavo Yunda-Guarin, Marcel Babin, Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire d'océanographie de Villefranche (LOV), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Microbienne (LOMIC), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Observatoire océanologique de Banyuls (OOB), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), LIttoral ENvironnement et Sociétés (LIENSs), La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Fédération de recherche de Roscoff (FR2424), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Université Paris Cité (UPCité), Applied Physics Laboratory [Seattle] (APL-UW), University of Washington [Seattle], Processus et interactions de fine échelle océanique (PROTEO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)
Subjects: [SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, General Earth and Planetary Sciences
Abstract: The Green Edge project was designed to investigate the onset, life, and fate of a phytoplankton spring bloom (PSB) in the Arctic Ocean. The lengthening of the ice-free period and the warming of seawater, amongst other factors, have induced major changes in Arctic Ocean biology over the last decades. Because the PSB is at the base of the Arctic Ocean food chain, it is crucial to understand how changes in the Arctic environment will affect it. Green Edge was a large multidisciplinary, collaborative project bringing researchers and technicians from 28 different institutions in seven countries together, aiming at understanding these changes and their impacts on the future. The fieldwork for the Green Edge project took place over two years (2015 and 2016) and was carried out from both an ice camp and a research vessel in Baffin Bay, in the Canadian Arctic. This paper describes the sampling strategy and the dataset obtained from the research cruise, which took place aboard the Canadian Coast Guard ship (CCGS) Amundsen in late spring and early summer 2016. The sampling strategy was designed around the repetitive, perpendicular crossing of the marginal ice zone (MIZ), using not only ship-based station discrete sampling but also high-resolution measurements from autonomous platforms (Gliders, BGC-Argo floats …) and under-way monitoring systems. The dataset is available at https://doi.org/10.17882/86417 (Bruyant et al., 2022).
Published: 2022
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10. Evidence of high N2 fixation rates in the temperate northeast Atlantic

Author: Morgane Gallinari, Marc Elskens, Debany Fonseca-Batista, Julie LaRoche, Lei Chou, Manon Tonnard, Valérie Michotey, Nolwenn Lemaitre, Hélène Planquette, François Fripiat, Virginie Riou, Frédéric Planchon, Natacha Brion, Xuefeng Li, Frank Dehairs, Géraldine Sarthou, Sophie Guasco, and Florian Deman
Subjects: 0303 health sciences, 010504 meteorology & atmospheric sciences, Ecology, Spring bloom, 01 natural sciences, 03 medical and health sciences, 13. Climate action, Temperate climate, Nitrogen fixation, Environmental science, Photic zone, 14. Life underwater, Transect, Bloom, Bay, Ecology, Evolution, Behavior and Systematics, 030304 developmental biology, 0105 earth and related environmental sciences, Earth-Surface Processes, Redfield ratio
Abstract: Diazotrophic activity and primary production (PP) were investigated along two transects (Belgica BG2014/14 and GEOVIDE cruises) off the western Iberian Margin and the Bay of Biscay in May 2014. Substantial N2 fixation activity was observed at 8 of the 10 stations sampled, ranging overall from 81 to 384 µ mol N m −2 d −1 (0.7 to 8.2 nmol N L −1 d −1) , with two sites close to the Iberian Margin situated between 38.8 and 40.7 ∘ N yielding rates reaching up to 1355 and 1533 µ mol N m −2 d −1 . Primary production was relatively lower along the Iberian Margin, with rates ranging from 33 to 59 mmol C m −2 d −1 , while it increased towards the northwest away from the peninsula, reaching as high as 135 mmol C m −2 d −1 . In agreement with the area-averaged Chl a satellite data contemporaneous with our study period, our results revealed that post-bloom conditions prevailed at most sites, while at the northwesternmost station the bloom was still ongoing. When converted to carbon uptake using Redfield stoichiometry, N2 fixation could support 1 % to 3 % of daily PP in the euphotic layer at most sites, except at the two most active sites where this contribution to daily PP could reach up to 25 %. At the two sites where N2 fixation activity was the highest, the prymnesiophyte–symbiont Candidatus Atelocyanobacterium thalassa (UCYN-A) dominated the nifH sequence pool, while the remaining recovered sequences belonged to non-cyanobacterial phylotypes. At all the other sites, however, the recovered nifH sequences were exclusively assigned phylogenetically to non-cyanobacterial phylotypes. The intense N2 fixation activities recorded at the time of our study were likely promoted by the availability of phytoplankton-derived organic matter produced during the spring bloom, as evidenced by the significant surface particulate organic carbon concentrations. Also, the presence of excess phosphorus signature in surface waters seemed to contribute to sustaining N2 fixation, particularly at the sites with extreme activities. These results provide a mechanistic understanding of the unexpectedly high N2 fixation in productive waters of the temperate North Atlantic and highlight the importance of N2 fixation for future assessment of the global N inventory.
Published: 2019
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11. Role of small Rhizaria and diatoms in the pelagic silica production of the Sourther Ocean

Author: Brivaëla Moriceau, Jean-François Maguer, Andrés Gutiérrez-Rodríguez, Paul Tréguer, Mikel Latasa, Fabrice Not, Morgane Gallinari, Natalia Llopis Monferrer, Matthew H. Pinkerton, Aude Leynaert, Karl A. Safi, Stéphane L'Helguen, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), National Institute of Water and Atmospheric Research [Wellington] (NIWA), Centro Oceanográfico de Gijón (IEO), ANR-18-CE01-0011,RadiCal,Calibration des isotopes stable du silicium des Radiolaires : Développement d'un nouveau paleo-indicateur du cycle du silicium marin(2018), ANR-16-CE01-0002,BioPSis,La pompe biologique de carbone: 2 silicifiés essentiels(2016), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Adaptation et diversité en milieu marin (ADMM), Institut national des sciences de l'Univers (INSU - CNRS)-Station biologique de Roscoff (SBR), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Silica paradox, 010504 meteorology & atmospheric sciences, Aquatic Science, Biogenic silica, 01 natural sciences, Silica export, chemistry.chemical_compound, Silica production, Ocean gyre, Photic zone, 14. Life underwater, Silicic acid, Medio Marino, oceanography, Centro Oceanográfico de Gijón, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Polar front, Diatoms, geography, geography.geographical_feature_category, biology, 010604 marine biology & hydrobiology, limnology, fungi, plankton, Rhizaria, Pelagic zone, 15. Life on land, Particulates, biology.organism_classification, chemistry, 13. Climate action, silica, Environmental chemistry, Souther Ocean, Environmental science
Abstract: We examined biogenic silica production and elementary composition (biogenic Si, particulate organic carbon and particulate organic nitrogen) of Rhizaria and diatoms in the upper 200 m along a transect in the Southwest Pacific sector of the Southern Ocean during austral summer (January–February 2019). From incubations using the 32Si radioisotope, silicic acid uptake rates were measured at 15 stations distributed in the Polar Front Zone, the Southern Antarctic Circumpolar Current and the Ross Sea Gyre. Rhizaria cells are heavily silicified (up to 7.6 nmol Si cell−1), displaying higher biogenic Si content than similar size specimens found in other areas of the global ocean, suggesting a higher degree of silicification of these organisms in the silicic acid rich Southern Ocean. Despite their high biogenic Si and carbon content, the Si/C molar ratio (average of 0.05 ± 0.03) is quite low compared to that of diatoms and relatively constant regardless of the environmental conditions. The direct measurements of Rhizaria's biogenic Si production (0.8–36.8 μmol Si m−2 d−1) are of the same order of magnitude than previous indirect estimations, confirming the importance of the Southern Ocean for the global Rhizaria silica production. However, diatoms largely dominated the biogenic Si standing stock and production of the euphotic layer, with low rhizarians' abundances and biogenic Si production (no more than 1%). In this manuscript, we discuss the Antarctic paradox of Rhizaria, that is, the potential high accumulation rates of biogenic Si due to Rhizaria in siliceous sediments despite their low production rates in surface waters., SI
Published: 2021
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12. Effect of P depletion on the functional pools of diatom carbohydrates, and their utilization by bacterial communities

Author: Julien Quere, Claire Labry, Daniel Delmas, Morgane Gallinari, Agnes Youenou, Brivaëla Moriceau, Dynamiques des Écosystèmes Côtiers (DYNECO), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre de Biologie pour la Gestion des Populations (UMR CBGP), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro - Montpellier SupAgro, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Dynamiques de l'Environnement Côtier (DYNECO), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Université de Montpellier (UM)-Institut de Recherche pour le Développement (IRD [France-Sud])-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), and Moriceau, Brivaëla
Subjects: 0106 biological sciences, glucosidase, Carbohydrate, Mineralization, 010504 meteorology & atmospheric sciences, chemistry.chemical_element, Aquatic Science, Polysaccharide, 01 natural sciences, Mineralization (biology), Cell wall, mineralization, bacteria, Ecology, Evolution, Behavior and Systematics, 0105 earth and related environmental sciences, chemistry.chemical_classification, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Ecology, biology, Bacteria, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, 010604 marine biology & hydrobiology, Phosphorus, fungi, Diatom, biology.organism_classification, diatom, Thalassiosira weissflogii, chemistry, Biochemistry, carbohydrate, P limitation, Phytoplankton, phytoplankton, Glucosidase
Abstract: Phosphorus (P) limitation of phytoplankton growth is known to affect the accumulation and release of carbohydrates (CHO) by micro-algae. However, relatively little is known about the fate of algal exudates, notably their bacterial degradation. The CHO chemical characterization is also not exhaustive, especially in ‘functional’ pools relevant for phytoplankton physiology (particulate reserve [R] or structural [S] CHO) and for bacterial degradation (dissolved mono- [MDCHO] and polysaccharides [P-DCHO]). In this study, we investigated how P depletion and repletion affect the CHO composition in diatomThalassiosira weissflogiicultures, and the shortterm response of free and diatom-attached bacteria in terms of abundance and potential βglucosidase activity (βGlc). The bacterial inoculum was composed of the bacterial consortiums of diatom precultures and a natural bacterial community from the Bay of Brest. P depletion favored CHO accumulation in diatom cells, mainly as R i.e. soluble CHO accumulated in cytoplasm, but also as S, polysaccharides linked to the cell wall. The R:S ratio was high in the present diatom cultures. The high M-DCHO observed in P-deplete cultures (twice that of P-replete cultures) when P-DCHO remained quite similar is explained both by active polysaccharide hydrolysis (very high potential βGlc of attached bacteria) and reduced uptake of M-DCHO by Pdepleted bacteria. P depletion of heterotrophic bacteria favors labile CHO accumulation, which may affect particle potential aggregation. However, the remarkably constant M-DCHO concentration over time for both conditions suggests tight coupling between phytoplankton accumulation, release, polymer hydrolysis and monomer uptake by bacteria.
Published: 2020
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13. Element enrichment and provenance of the detrital component in Holocene sediments from the western Black Sea

Author: Valentina Y. Darakchieva, C.-Dieter Garbe-Schönberg, Kjell Billström, Lyubomir Dimitrov, Olivier Ragueneau, Vesselin M. Dekov, Morgane Gallinari, George D. Kamenov, Ellen Kooijman, Tokyo University of Marine Science and Technology (TUMSAT), Unité de recherche Géosciences Marines (Ifremer) (GM), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institute of Mineralogy and Crystallography - IMC (Sofia, Bulgaria), Bulgarian Academy of Sciences (BAS), Swedish Museum of Natural History (NRM), Christian-Albrechts-Universität zu Kiel (CAU), University of Florida [Gainesville] (UF), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Oceanology of Bulgarian Academy of Sciences (IO-BAS), Géosciences Marines (GM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Atmospheric Science, Provenance, 010504 meteorology & atmospheric sciences, Geochemistry, Ocean Engineering, Aquatic Science, Oceanography, 01 natural sciences, Sr-Nd-Pb-isotopes, lcsh:Oceanography, Water column, [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry, 14. Life underwater, lcsh:GC1-1581, Anoxic, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Isotope analysis, Holocene, 010604 marine biology & hydrobiology, Sediment, Authigenic, 6. Clean water, Diagenesis, Element enrichment, Black Sea, 13. Climate action, Enrichment factor, Clay minerals, Geology
Abstract: Place: Sopot Publisher: Polish Acad Sciences Inst Oceanology WOS:000528728600003; International audience; Concentrations of a large set of major and trace elements, and Sr, Nd and Pb isotope ratios were measured in Holocene sediments cored in the western deep Black Sea in order to unravel: (1) the controls of element enrichment, and (2) sources of the detrital component. The transition of the basin from oxic to euxinic resulted in enrichment or depletion in a number of elements in the deep-sea sediments. Authigenic Fe enrichment appears to depend on the amount of Fe mobilized from the sediment through the benthic redox shuttle mechanism and free H2S in the water column (degree of “euxinization”). Manganese enrichment is controlled by diagenetic reactions within the sediment: the dissolution of Mn minerals, Mn2+ diffusion upward and reprecipitation. Barium enrichment is also controlled by diagenetic reactions, sulfate reduction and methanogenesis, that take place above and below the sulfate-methane transition, respectively. The major part of V, Co, Ni, Cu, Zn, Cr, Mo, Cd and Sb is inferred to have co-precipitated with Fe in the euxinic deep waters and to have been incorporated into authigenic Fe-sulfides. Basin reservoir effect additionally influences the Mo enrichment. The U enrichment is interpreted to have a different origin in the two organic-rich stratigraphic units (II and I). It is inferred to be: (i) at the expense of the U inventory of the deepwater pool and a result of inorganic reduction of U at euxinic conditions in the lower Unit II; and (ii) at the expense of the U inventory of the surface water pool and a result of biogenic uptake and transfer to the sediment by the plankton in the upper Unit I. The high field strength elements are closely linked to the detrital component and their depletion in the organic-rich sediments reflects a dilution of the detrital component by the biogenic one. The enrichments of REE, Sn and Th are likely controlled by adsorption on clay minerals. Sr-Nd-Pb isotope compositions of the alumino-silicate component of the studied sediments are relatively uniform. They are most likely controlled by riverine suspended matter supplied mainly in the NW Black Sea (Danube Delta) and transported southward by marine currents, and to a lesser degree by suspended matter from the small rivers draining SE Bulgaria and NW Turkey. Wind-blown dust from the Sahara Desert appears to have a minor contribution to the alumino-silicate component of the sediments. The slight shift in the Pb isotopes in Unit I upper layers is possibly caused by the addition of anthropogenic Pb.
Published: 2020
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14. New guidelines for the application of Stokes' models to the sinking velocity of marine aggregates

Author: Christina L. De La Rocha, Morgane Gallinari, Anja Engel, Frédéric A. C. Le Moigne, Brivaëla Moriceau, E. C. Laurenceau-Cornec, Morten Hvitfeldt Iversen, Jordan Toullec, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Alfred Wegener Institute for Polar and Marine Research (AWI), Center for Marine Environmental Sciences [Bremen] (MARUM), Universität Bremen, Funding Information Australian Research Council. Grant Number: FL160100131 CalMaro FP7 Marie Curie Initial Training Network. Grant Number: 215157 EURO‐BASIN. Grant Number: 264933, European Project: 264933,EC:FP7:ENV,FP7-ENV-2010,EURO-BASIN(2010), European Project: 215157,EC:FP7:PEOPLE,FP7-PEOPLE-2007-1-1-ITN,CALMARO(2008), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, Drag coefficient, 010504 meteorology & atmospheric sciences, SOLID PARTICLES, Aquatic Science, RESPIRATION RATES, Oceanography, 01 natural sciences, Fractal dimension, Sphericity, Physics::Geophysics, CARBON EXPORT, Physics::Fluid Dynamics, symbols.namesake, SETTLING VELOCITY, Settling, 14. Life underwater, FECAL PELLETS, Porosity, IMAGE-ANALYSIS, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 010604 marine biology & hydrobiology, Aggregate (data warehouse), Reynolds number, Mechanics, OCEAN BIOGEOCHEMICAL MODEL, 13. Climate action, symbols, Particle, Environmental science, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, PARTICULATE ORGANIC-MATTER, DUST-DEPOSITION, FRACTAL DIMENSIONS
Abstract: International audience; Numerical simulations of ocean biogeochemical cycles need to adequately represent particle sinking velocities (SV). For decades, Stokes' Law estimating particle SV from density and size has been widely used. But while Stokes' Law holds for small, smooth, and rigid spheres settling at low Reynolds number, it fails when applied to marine aggregates complex in shape, structure, and composition. Minerals and zooplankton can alter phytoplankton aggregates in ways that change their SV, potentially improving the applicability of Stokes' models. Using rolling cylinders, we experimentally produced diatom aggregates in the presence and absence of minerals and/or microzooplankton. Minerals and to a lesser extent microzooplankton decreased aggregate size and roughness and increased their sphericity and compactness. Stokes' Law parameterized with a fractal porosity modeled adequately size-SV relationships for mineral-loaded aggregates. Phytoplankton-only aggregates and those exposed to microzooplankton followed the general Navier-Stokes drag equation suggesting an indiscernible effect of microzooplankton and a drag coefficient too complex to be calculated with a Stokes' assumption. We compared our results with a larger data set of ballasted and nonballasted marine aggregates. This confirmed that the size-SV relationships for ballasted aggregates can be simulated by Stokes' models with an adequate fractal porosity parameterization. Given the importance of mineral ballasting in the ocean, our findings could ease biogeochemical model parameterization for a significant pool of particles in the ocean and especially in the mesopelagic zone where the particulate organic matter : mineral ratio decreases. Our results also reinforce the importance of accounting for porosity as a decisive predictor of marine aggregate SV.
Published: 2019
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15. Revisiting the distribution of oceanic N2 fixation and estimating diazotrophic contribution to marine production

Author: Morgane Gallinari, Weiyi Tang, Frank Dehairs, Nicolas Cassar, Debany Fonseca-Batista, Aridane G. González, Seaver Wang, Scott M. Gifford, Géraldine Sarthou, Hélène Planquette, Nicholas School of the Environment, Duke University [Durham], Analytical, Environmental and Geo- Chemistry, Vrije Universiteit Brussel (VUB), University of North Carolina System (UNC), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Instituto de Oceanografía y Cambio Global (IOCAG), Université de Las Palmas de Gran Canaria [Espagne] (ULPGC), ANR-12-PDOC-0025,BITMAP,Biodisponibilité du fer et des métaux traces dans les particules marines(2012), ANR-10-LABX-0019,LabexMER,LabexMER Marine Excellence Research: a changing ocean(2010), Faculty of Sciences and Bioengineering Sciences, Analytical, Environmental & Geo-Chemistry, Earth System Sciences, Chemistry, and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0301 basic medicine, Chemistry(all), Science, Biogeography, Regulating factors, General Physics and Astronomy, chemistry.chemical_element, Distribution (economics), 02 engineering and technology, Physics and Astronomy(all), General Biochemistry, Genetics and Molecular Biology, Carbon cycle, 03 medical and health sciences, DINITROGEN-FIXATION, 14. Life underwater, RATES, lcsh:Science, ACETYLENE, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Multidisciplinary, ATLANTIC TIME-SERIES, Biochemistry, Genetics and Molecular Biology(all), business.industry, Phosphorus, COASTAL, ACL, fungi, General Chemistry, Plankton, 021001 nanoscience & nanotechnology, CAVITY RING, 030104 developmental biology, Oceanography, chemistry, 13. Climate action, Nitrogen fixation, Environmental science, lcsh:Q, Diazotroph, N2 FIXATION, NITROGEN-FIXATION, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, 0210 nano-technology, business, CARBON-CYCLE, GAS-EXCHANGE
Abstract: Marine N2 fixation supports a significant portion of oceanic primary production by making N2 bioavailable to planktonic communities, in the process influencing atmosphere-ocean carbon fluxes and our global climate. However, the geographical distribution and controlling factors of marine N2 fixation remain elusive largely due to sparse observations. Here we present unprecedented high-resolution underway N2 fixation estimates across over 6000 kilometers of the western North Atlantic. Unexpectedly, we find increasing N2 fixation rates from the oligotrophic Sargasso Sea to North America coastal waters, driven primarily by cyanobacterial diazotrophs. N2 fixation is best correlated to phosphorus availability and chlorophyll-a concentration. Globally, intense N2 fixation activity in the coastal oceans is validated by a meta-analysis of published observations and we estimate the annual coastal N2 fixation flux to be 16.7 Tg N. This study broadens the biogeography of N2 fixation, highlights the interplay of regulating factors, and reveals thriving diazotrophic communities in coastal waters with potential significance to the global nitrogen and carbon cycles. The geographical distribution and controlling factors of marine N2 fixation are understudied. Here the authors find increasing rates of N2 fixation from the Sargasso Sea to the coastal waters of North America, driven primarily by cyanobacterial diazotrophs and best correlated with phosphorus availability and chlorophyll-a concentrations.
Published: 2019
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16. Effect of trace metal-limited growth on the postmortem dissolution of the marine diatomPseudo-nitzschia delicatissima

Author: Julia Boutorh, Brivaëla Moriceau, Olivier Ragueneau, Morgane Gallinari, and Eva Bucciarelli
Subjects: 0106 biological sciences, Atmospheric Science, Global and Planetary Change, 010504 meteorology & atmospheric sciences, biology, 010604 marine biology & hydrobiology, Mineralogy, chemistry.chemical_element, Biogenic silica, biology.organism_classification, 01 natural sciences, Copper, Silicate, chemistry.chemical_compound, chemistry, Environmental chemistry, Environmental Chemistry, Photic zone, Trace metal, Seawater, Pseudo-nitzschia, Dissolution, Geology, 0105 earth and related environmental sciences, General Environmental Science
Abstract: We investigated the effects of iron (Fe) and copper (Cu) limitations on biogenic silica (bSiO(2)) dissolution kinetics of the marine diatom Pseudo-nitzschia delicatissima during a 3 week batch dissolution experiment. The dissolution of this species was faster during the first week than thereafter. Modeling results from four dissolution models and scanning electron microcopy images suggested the successive dissolution of two phases of bSiO(2), with two different dissolution constants. Micronutrient limitation during growth affected the respective proportion of the two phases and their dissolution constants. After 3 weeks of dissolution, frustules from micronutrient-limited diatoms were better preserved than those of replete cells. Our results also confirm that micronutrient-limited cells may export more Si relative to N than replete cells and may increase the silicate pump: This may not only be due to a higher degree of silicification of the live cells but also to a decoupling between the recycling of Si and N during dissolution. We suggest that a mechanistic understanding of the evolution of the dissolution constant during dissolution is needed. This would improve the parameterization of dissolution in ecosystem models, and ultimately their predictions on the amount of bSiO(2) that dissolves in the photic zone, and the amount of bSiO(2) that is exported to the seafloor.
Published: 2016
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17. Revisiting the distribution of oceanic N

Author: Weiyi, Tang, Seaver, Wang, Debany, Fonseca-Batista, Frank, Dehairs, Scott, Gifford, Aridane G, Gonzalez, Morgane, Gallinari, Hélène, Planquette, Géraldine, Sarthou, and Nicolas, Cassar
Subjects: Chlorophyll A, Nitrogen Fixation, RNA, Ribosomal, 16S, fungi, North America, Biological Availability, Marine Biology, Phosphorus, Cyanobacteria, Plankton, Atlantic Ocean, Phylogeny, Article
Abstract: Marine N2 fixation supports a significant portion of oceanic primary production by making N2 bioavailable to planktonic communities, in the process influencing atmosphere-ocean carbon fluxes and our global climate. However, the geographical distribution and controlling factors of marine N2 fixation remain elusive largely due to sparse observations. Here we present unprecedented high-resolution underway N2 fixation estimates across over 6000 kilometers of the western North Atlantic. Unexpectedly, we find increasing N2 fixation rates from the oligotrophic Sargasso Sea to North America coastal waters, driven primarily by cyanobacterial diazotrophs. N2 fixation is best correlated to phosphorus availability and chlorophyll-a concentration. Globally, intense N2 fixation activity in the coastal oceans is validated by a meta-analysis of published observations and we estimate the annual coastal N2 fixation flux to be 16.7 Tg N. This study broadens the biogeography of N2 fixation, highlights the interplay of regulating factors, and reveals thriving diazotrophic communities in coastal waters with potential significance to the global nitrogen and carbon cycles., The geographical distribution and controlling factors of marine N2 fixation are understudied. Here the authors find increasing rates of N2 fixation from the Sargasso Sea to the coastal waters of North America, driven primarily by cyanobacterial diazotrophs and best correlated with phosphorus availability and chlorophyll-a concentrations.
Published: 2018

18. Supplementary material to 'Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise'

Author: Géraldine Sarthou, Pascale Lherminier, Eric P. Achterberg, Fernando Alonso-Pérez, Eva Bucciarelli, Julia Boutorh, Vincent Bouvier, Edward A. Boyle, Pierre Branellec, Lidia I. Carracedo, Nuria Casacuberta, Maxi Castrillejo, Marie Cheize, Leonardo Contreira Pereira, Daniel Cossa, Nathalie Daniault, Emmanuel De Saint-Léger, Frank Dehairs, Feifei Deng, Floriane Desprez de Gésincourt, Jérémy Devesa, Lorna Foliot, Debany Fonseca-Batista, Morgane Gallinari, Maribel I. García-Ibáñez, Arthur Gourain, Emilie Grossteffan, Michel Hamon, Lars Eric Heimbürger, Gideon M. Henderson, Catherine Jeandel, Catherine Kermabon, François Lacan, Philippe Le Bot, Manon Le Goff, Emilie Le Roy, Alison Lefèbvre, Stéphane Leizour, Nolwenn Lemaitre, Pere Masqué, Olivier Ménage, Jan-Lukas Menzel Barraqueta, Herlé Mercier, Fabien Perault, Fiz F. Pérez, Hélène F. Planquette, Frédéric Planchon, Arnout Roukaerts, Virginie Sanial, Raphaëlle Sauzède, Rachel U. Shelley, Gillian Stewart, Jill N. Sutton, Yi Tang, Nadine Tisnérat-Laborde, Manon Tonnard, Paul Tréguer, Pieter van Beek, Cheryl M. Zurbrick, and Patricia Zunino
Published: 2018
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19. Evidence of high N2 fixation rates in productive waters of the temperate Northeast Atlantic

Author: Morgane Gallinari, Lei Chou, Nolwenn Lemaitre, Forian Deman, Xuefeng Li, Frank Dehairs, Natacha Brion, Sophie Guasco, Debany Fonseca-Batista, Hélène Planquette, Valérie Michotey, Marc Elskens, Manon Tonnard, Géraldine Sarthou, François Fripiat, Virginie Riou, and Frédéric Planchon
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, biology, 010604 marine biology & hydrobiology, Spring bloom, biology.organism_classification, 01 natural sciences, Zooplankton, Oceanography, Algae, Phytoplankton, Nitrogen fixation, Temperate climate, Environmental science, Diazotroph, Bay, 0105 earth and related environmental sciences
Abstract: Diazotrophic activity and primary production (PP) were investigated along two transects (Belgica BG2014/14 and GEOVIDE cruises) off the western Iberian Margin and the Bay of Biscay (38.8–46.5° N; 8.0–19.7° W) in May 2014 close to the end of the spring bloom. We report substantial N2 fixation activities, reaching up to 65 nmol N L−1 d−1 and 1533 µmol N m−2 d−1 close to the Iberian Margin between 38.8° N and 40.7° N. Similar figures in the basin have only been reported in the temperate and tropical western North Atlantic waters with coastal, shelf or mesohaline characteristics, as opposed to the mostly open ocean conditions studied here. In agreement with previous studies, the qualitative assessment of nifH gene diversity (encoding the nitrogenase enzyme that fixes N2) suggested a predominance of heterotrophic diazotrophs, and the absence of filamentous cyanobacteria. At the sites where N2 fixation activity was highest sequences affiliated to UCYN-A1, obligate symbiont of eukaryotic prymnesiophyte algae, were recovered. The remaining phylotypes were non-cyanobacterial diazotrophs, known to live in association with suspended particles and zooplankton (i.e., Bacteroidetes, Firmicutes and Proteobacteria). Outside the area of exceptional activity, N2 fixation in the open ocean and at shelf-influenced sites was also relatively high, ranging from 81 to 384 µmol N m−2 d−1, but was undetectable in the central Bay of Biscay. We propose that the unexpectedly high heterotrophic N2 fixation activity recorded at the time of our study was sustained by the availability of phytoplankton derived organic matter (dissolved and/or particulate) resulting from the ongoing to post spring bloom. We pose that this organic material not only sustained bacterial production, but also provided sufficient nutrients essential for the nitrogenase activity (e.g., phosphorus). Dissolved Fe was supplied through atmospheric dust deposition during the month preceding our study and through advection of surface waters from the subtropical region and the shelf area. Our findings stress the need for a more detailed monitoring of the spatial and temporal distribution of oceanic N2 fixation in productive waters of the temperate North Atlantic to better constrain the basin-scale nitrogen input to the ocean inventory.
Published: 2018
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20. Supplementary material to 'Evidence of high N2 fixation rates in productive waters of the temperate Northeast Atlantic'

Author: Debany Fonseca-Batista, Xuefeng Li, Virginie Riou, Valérie Michotey, Forian Deman, François Fripiat, Sophie Guasco, Natacha Brion, Nolwenn Lemaitre, Manon Tonnard, Morgane Gallinari, Hélène Planquette, Frédéric Planchon, Géraldine Sarthou, Marc Elskens, Lei Chou, and Frank Dehairs
Published: 2018
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21. Supplementary material to 'Dissolved iron in the North Atlantic Ocean and Labrador Sea along the GEOVIDE section (GEOTRACES section GA01)'

Author: Manon Tonnard, Hélène Planquette, Andrew R. Bowie, Pier van der Merwe, Morgane Gallinari, Floriane Desprez de Gésincourt, Yoan Germain, Arthur Gourain, Marion Benetti, Gilles Reverdin, Paul Tréguer, Julia Boutorh, Marie Cheize, Jan-Lukas Menzel Barraqueta, Leonardo Pereira-Contreira, Rachel Shelley, Pascale Lherminier, and Géraldine Sarthou
Published: 2018
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22. Copepods Boost the Production but Reduce the Carbon Export Efficiency by Diatoms

Author: Annick Masson, Richard S. Lampitt, Morten Hvitfeldt Iversen, Julia Boutorh, Beatriz Beker, Antti Jussi O. Evertsen, Manon Le Goff, Rudolph Corvaisier, Morgane Gallinari, Sarah L. C. Giering, Brivaëla Moriceau, Maria Stockenreiter, Marja Koski, Christina L. De La Rocha, Anne Donval, Christophe Lambert, Alain Le Mercier, Nathalie Coffineau, Herwig Stibor, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Alfred Wegener Institute for Polar and Marine Research (AWI), Center for Marine Environmental Sciences [Bremen] (MARUM), Universität Bremen, Department of Biology [Trondheim] (IBI NTNU), Norwegian University of Science and Technology [Trondheim] (NTNU), Norwegian University of Science and Technology (NTNU)-Norwegian University of Science and Technology (NTNU), National Oceanography Centre [Southampton] (NOC), University of Southampton, DTU Aqua, National Institute of Aquatic Resources, Technical University of Denmark [Lyngby] (DTU), Ludwig-Maximilians-Universität München (LMU), European Project: 264933,EC:FP7:ENV,FP7-ENV-2010,EURO-BASIN(2010), European Project: 261520,EC:FP7:INFRA,FP7-INFRASTRUCTURES-2010-1,HYDRALAB IV(2010), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Danmarks Tekniske Universitet = Technical University of Denmark (DTU)
Subjects: zooplankton, 0106 biological sciences, lcsh:QH1-199.5, 010504 meteorology & atmospheric sciences, marine snow, Biological pump, Ocean Engineering, lcsh:General. Including nature conservation, geographical distribution, Aquatic Science, Biogenic silica, Oceanography, 01 natural sciences, Zooplankton, Plankton commuity, plankton community, Phytoplankton, Photic zone, SDG 14 - Life Below Water, 14. Life underwater, biogenic silica, lcsh:Science, POC, 0105 earth and related environmental sciences, Water Science and Technology, Marine snow, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Global and Planetary Change, biology, ACL, 010604 marine biology & hydrobiology, fungi, Bay of Hopavågen, Mesocosm, biology.organism_classification, mesocosm, Diatom, Environmental chemistry, Bay of Hopavagen, Environmental science, lcsh:Q, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, biological pump, Copepod
Abstract: The fraction of net primary production that is exported from the euphotic zone as sinking particulate organic carbon (POC) varies notably through time and from region to region. Phytoplankton containing biominerals, such as silicified diatoms have long been associated with high export fluxes. However, recent reviews point out that the magnitude of export is not controlled by diatoms alone, but determined by the whole plankton community structure. The combined effect of phytoplankton community composition and zooplankton abundance on export flux dynamics, were explored using a set of 12 large outdoor mesocosms. All mesocosms received a daily addition of minor amounts of nitrate and phosphate, while only 6 mesocosms received silicic acid (dSi). This resulted in a dominance of diatoms and dinoflagellate in the +Si mesocosms and a dominance of dinoflagellate in the −Si mesocosms. Simultaneously, half of the mesocosms had decreased mesozooplankton populations whereas the other half were supplemented with additional zooplankton. In all mesocosms, POC fluxes were positively correlated to Si/C ratios measured in the surface community and additions of dSi globally increased the export fluxes in all treatments highlighting the role of diatoms in C export. The presence of additional copepods resulted in higher standing stocks of POC, most probably through trophic cascades. However it only resulted in higher export fluxes for the −Si mesocosms. In the +Si with copepod addition (+Si +Cops) export was dominated by large diatoms with higher Si/C ratios in sinking material than in standing stocks. During non-bloom situations, the grazing activity of copepods decrease the export efficiency in diatom dominated systems by changing the structure of the phytoplankton community and/or preventing their aggregation. However, in flagellate-dominated system, the copepods increased phytoplankton growth, aggregation and fecal pellet production, with overall higher net export not always visible in term of export efficiency. Copyright © 2018 Moriceau, Iversen, Gallinari, Evertsen, Le Goff, Beker, Boutorh, Corvaisier, Coffineau, Donval, Giering, Koski, Lambert, Lampitt, Le Mercier, Masson, Stibor, Stockenreiter and De La Rocha. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Published: 2018
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23. Introduction to the French GEOTRACES North Atlantic Transect (GA01): GEOVIDE cruise

Author: Géraldine Sarthou, Pascale Lherminier, Eric P. Achterberg, Fernando Alonso-Pérez, Eva Bucciarelli, Julia Boutorh, Vincent Bouvier, Edward A. Boyle, Pierre Branellec, Lidia I. Carracedo, Nuria Casacuberta, Maxi Castrillejo, Marie Cheize, Leonardo Contreira Pereira, Daniel Cossa, Nathalie Daniault, Emmanuel De Saint-Léger, Frank Dehairs, Feifei Deng, Floriane Desprez de Gésincourt, Jérémy Devesa, Lorna Foliot, Debany Fonseca-Batista, Morgane Gallinari, Maribel I. García-Ibáñez, Arthur Gourain, Emilie Grossteffan, Michel Hamon, Lars Eric Heimbürger, Gideon M. Henderson, Catherine Jeandel, Catherine Kermabon, François Lacan, Philippe Le Bot, Manon Le Goff, Emilie Le Roy, Alison Lefèbvre, Stéphane Leizour, Nolwenn Lemaitre, Pere Masqué, Olivier Ménage, Jan-Lukas Menzel Barraqueta, Herlé Mercier, Fabien Perault, Fiz F. Pérez, Hélène F. Planquette, Frédéric Planchon, Arnout Roukaerts, Virginie Sanial, Raphaëlle Sauzède, Rachel U. Shelley, Gillian Stewart, Jill N. Sutton, Yi Tang, Nadine Tisnérat-Laborde, Manon Tonnard, Paul Tréguer, Pieter van Beek, Cheryl M. Zurbrick, Patricia Zunino, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut Cartografic de Catalunya (ICC), Institut Cartografic de Catalunya, Laboratoire des Sciences de l'Information et des Systèmes (LSIS), Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Arts et Métiers Paristech ENSAM Aix-en-Provence-Centre National de la Recherche Scientifique (CNRS), Institute for Research on Learning, National Oceanography Centre [Southampton] (NOC), University of Southampton, Physiologie et Ecophysiologie des Mollusques Marins (PE2M), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Institut Français de Recherche pour l'Exploitation de la Mer - Nantes (IFREMER Nantes), Université de Nantes (UN), Analytical and Environmental Chemistry and Earth System Sciences, Vrije Universiteit [Brussels] (VUB), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Spanish National Research Council (CSIC), UMS 3113, Institut Universitaire Européen de la Mer (IUEM), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO), Neuropsychopharmacologie, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut méditerranéen d'océanologie (MIO), Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN)-Aix Marseille Université (AMU)-Institut de Recherche pour le Développement (IRD), Laboratoire d'études en Géophysique et océanographie spatiales (LEGOS), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Océanographie Physique et Spatiale (LOPS), Institut de Ciencia i Tecnologia Ambientals (ICTA), Universitat Autònoma de Barcelona [Barcelona] (UAB), GEOMAR LEGOS, Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), School of Earth and Environmental Sciences [Queens New York], Queens College [New York], City University of New York [New York] (CUNY)-City University of New York [New York] (CUNY), Shenzhen Key Laboratory of Sensor Technology, Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Pierre et Marie Curie - Paris 6 (UPMC), and Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, 0303 health sciences, 03 medical and health sciences, 010504 meteorology & atmospheric sciences, 13. Climate action, [SDE.MCG]Environmental Sciences/Global Changes, 14. Life underwater, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, 030304 developmental biology, 0105 earth and related environmental sciences
Abstract: The GEOVIDE cruise, a collaborative project within the framework of the international GEOTRACES programme, was conducted along the French-led section in the North Atlantic Ocean (Section GA01), between 15 May and 30 June 2014. In this Special Issue, results from GEOVIDE, including physical oceanography and trace element and isotope cyclings, are presented among seventeen articles. Here, the scientific context, project objectives and scientific strategy of GEOVIDE are provided, along with an overview of the main results from the articles published in the special issue.
Published: 2018
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24. On the Potential Role of Phytoplankton Aggregates in Microplastic Sedimentation

Author: Philippe Soudant, Arnaud Huvet, Ika Paul-Pont, Hélène Hégaret, Morgane Gallinari, Christophe Lambert, Marc Long, and Brivaëla Moriceau
Subjects: Microplastics, Oceanography, 010504 meteorology & atmospheric sciences, Phytoplankton, Environmental science, 010501 environmental sciences, Sedimentation, 01 natural sciences, 0105 earth and related environmental sciences
Published: 2017
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25. Influence of seasonal phytodetritus deposition on biogenic silica dissolution in marine sediments—Potential effects on preservation

Author: Morgane Gallinari, Dirk Rickert, David J. DeMaster, Olivier Ragueneau, Hilairy E. Hartnett, Carrie J. Thomas, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Department of MEAS, North Carolina State University [Raleigh] (NC State), University of North Carolina System (UNC)-University of North Carolina System (UNC), Department of Geological Sciences, Arizona State University [Tempe] (ASU), Department of Chemistry and Biochemistry [Tempe], GEOMAR Froschungzentrum, Helmholtz Centre for Ocean Research [Kiel] (GEOMAR), and BENGAL (MAS3-CT95-0018) and ORFOIS (EVK2-CT-2001-00100) NSF-FOODBANCS program INSU
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Dissolved silica, 010604 marine biology & hydrobiology, Phytodetritus, Sediment, Biogenic silica, Oceanography, 01 natural sciences, Diagenesis, Benthic zone, [SDE]Environmental Sciences, 14. Life underwater, Flow-through reactors, Deposition (chemistry), Bioturbation, Dissolution, Geology, 0105 earth and related environmental sciences
Abstract: International audience; The deposition of fresh phytoplankton detritus (phytodetritus) following phytoplankton blooms may influence biogenic silica (BSi) dissolution in marine sediments. We studied BSi dissolution properties before, during, and after periods of phytodetritus deposition during time-series field programs in the abyssal North Atlantic (the BENGAL project), and on the West Antarctic Peninsula Shelf (the FOODBANCS project). Dissolution experiments, performed by means of flow-through reactors, showed temporal variations in the dissolution properties of BSi in the sediment column after phytodetritus deposition. This non-steady-state character of benthic silica dynamics is an important aspect of pelagic-benthic coupling. The last FOODBANCS cruise occurred after a phytodetritus deposition event, and yielded high pore-water dissolved silica (DSi) concentrations and DSi effluxes in the upper centimetres of the sediment column, suggesting a rapid turnover of recently deposited siliceous material. Higher dissolution rates were measured in the phytodetritus-rich sediments relative to surface sediments collected during previous seasons on earlier FOODBANCS cruises. During the BENGAL project, high dissolution rates were measured at depth in the sediment column only after a summer phytodetritus deposition event. In the highly detrital sediment matrix of the abyssal North Atlantic Ocean, resolution of increased dissolution rates and experimental artefacts of the flow-through reactors can be difficult because of the low abundance of BSi. Depending on the sediment matrix, bioturbation can play a crucial role in transporting fresh BSi particles to depth, where DSi concentrations are close to experimentally determined BSi solubilities. The potential impacts of such processes on BSi preservation are discussed. We suggest that future models of BSi early diagenesis should include the rapid mixing of freshly deposited particles if we want to describe further the preservation of BSi in marine sediments.
Published: 2008
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26. Net and gross incorporation of nitrogen by marine copepods fed on 15N-labelled diatoms: Methodology and trophic studies

Author: Gerd Slawyk, Benoît Sautour, Olivier Ragueneau, Dorothée Vincent, Laurent Seuront, Morgane Gallinari, Stéphane L'Helguen, and Géraldine Sarthou
Subjects: biology, chemistry.chemical_element, Aquatic Science, biology.organism_classification, Nitrogen, chemistry.chemical_compound, Animal science, chemistry, Thalassiosira weissflogii, Algae, Phytoplankton, Botany, Ammonium, Nitrogen cycle, Ecology, Evolution, Behavior and Systematics, Copepod, Trophic level
Abstract: The stable isotope of nitrogen ( 15 N) and an appropriate three-compartment model were used in two 24-h lasting feeding experiments to trace the flow of N through the copepod Acartia discaudata and Calanus helgolandicus fed on 15 N-labelled Skeletonema costatum and Thalassiosira weissflogii, respectively. Details of the labelling technique and principles of the computation of N transport rates are given. At the end of a single 24-h feeding period only about one third of the total amount of N ingested by A. discaudata was incorporated into the copepod's body N; we refer to this rate as net incorporation. Most of the N ingested was lost as ammonium (48% of total N ingested), followed by losses in the form of eggs+fecal pellets (13%) and dissolved organic N (DON, 9%). The sum of net incorporation and the latter losses is defined as gross incorporation. Net incorporation by C. helgolandicus and N losses did not vary over time during a 24 h lasting time-series feeding experiment. On average, 79% of total N ingested was actually incorporated by the copepod whereas mean N losses as ammonium, eggs+fecal pellets represented only 12 and 9%, respectively. After a 24-h feeding period only 2% of N ingested was lost as DON. Inspection of individual DON pathways showed that both A. discaudata and C. helgolandicus highly contributed to total DON production via direct excretion (79 and 64%, respectively). The remaining DON appearing in the DON pool was derived from phytoplankton via direct release and/or indirect release (copepod ‘sloppy feeding’). © 2007 Elsevier B.V. All rights reserved.
Published: 2007
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27. Constraining biogenic silica dissolution in marine sediments: a comparison between diagenetic models and experimental dissolution rates

Author: Olivier Ragueneau, Karline Soetaert, Morgane Gallinari, David J. DeMaster, K. Khalil, Christophe Rabouille, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Océan et Interfaces (OCEANIS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Netherlands Institute of Ecology (NIOO-KNAW), Department of MEAS, North Carolina State University [Raleigh] (NC State), University of North Carolina System (UNC)-University of North Carolina System (UNC), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), and Ecosystems Studies
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Equatorial Pacific, Mineralogy, Biogenic silica, Oceanography, 01 natural sciences, chemistry.chemical_compound, Flux (metallurgy), Biogenic silica dissolution, Sediment–water interface, Environmental Chemistry, 14. Life underwater, Southern Ocean, Dissolution, Early diagenesis, 0105 earth and related environmental sciences, Water Science and Technology, 010604 marine biology & hydrobiology, North Atlantic, Sediment, General Chemistry, Reprecipitation, Silicate, Diagenesis, chemistry, 13. Climate action, [SDE]Environmental Sciences, Seawater, Silica cycle, Geology
Abstract: International audience; The processes controlling preservation and recycling of particulate biogenic silica in sediments must be understood in order to calculate oceanic silica mass balances. The new contribution of this work is the coupled use of advanced models including reprecipitation and different phases of biogenic silica with different dissolution characteristics as well as new data sets concerning experimental dissolution rates of marine particles and sediment opal obtained in flow-through reactors. We have used three models representing early diagenesis of biogenic silica in sediments that calculate the vertical distributions of dissolved silicate and solid silica in sediments. Model 1 contains one type of biogenic silica and the dissolution rate is constant, whereas model 2 contains a variable dissolution rate constant with sediment depth (representing aging) and one type of biogenic silica. Model 3 incorporates aging by describing two types of biogenic silica that differ by their dissolution properties. An explicit term of reprecipitation is incorporated into the three models. The distributions of dissolved silicate and solid silica predicted by steady-state calculations are compared to 4 observed data sets, from the Southern Ocean, the Equatorial Pacific and the North Atlantic, covering a wide range of sediment compositions, from opal-rich to opal-poor sediments. After adjustment of the critical parameters (the apparent silica dissolution rate constants, the biogenic silica flux deposited at the sediment-water interface and the reprecipitation rate), the second and third models provide good agreements between predicted and measured dissolved Si and solid silica profiles for each data set, except for the second model in the Equatorial Pacific. However, a large discrepancy between the experimentally derived dissolution rate constants and those calculated by the models is observed at all sites at depth in the sediment, suggesting that either artifacts arise during dissolution experiments such as over-representation of rapidly dissolving silica or variation of dissolution properties during the experimental procedures or the model oversimplifies the processes associated to silica dissolution and alumino-silicate reprecipitation and their interaction.
Published: 2007
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28. Interactions between microplastics and phytoplankton aggregates: Impact on their respective fates

Author: Philippe Soudant, Morgane Gallinari, Jean Raffray, Arnaud Huvet, Brivaëla Moriceau, Christophe Lambert, Marc Long, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), and Institut de Recherche pour le Développement (IRD)
Subjects: Microplastics, Frustule, [SDE.MCG]Environmental Sciences/Global Changes, Biogenic silica, Oceanography, Permeability, Water column, [SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems, Algae, Phytoplankton, Environmental Chemistry, Organic matter, 14. Life underwater, Vertical export, Water Science and Technology, chemistry.chemical_classification, [SDV.BA.MVSA]Life Sciences [q-bio]/Animal biology/Veterinary medicine and animal Health, biology, Microplastic sink, Ecology, ACL, General Chemistry, Diatom and cryptophyte aggregates, biology.organism_classification, [SDV.BA.ZI]Life Sciences [q-bio]/Animal biology/Invertebrate Zoology, Diatom, chemistry, 13. Climate action, Settling rate, Environmental chemistry, [SDV.SA.STP]Life Sciences [q-bio]/Agricultural sciences/Sciences and technics of fishery, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, [SDV.EE.IEO]Life Sciences [q-bio]/Ecology, environment/Symbiosis
Abstract: International audience; Plastic debris are resistant to degradation, and therefore tend to accumulate in marine environment. Nevertheless recent estimations of plastic concentrations at the surface of the ocean were lower than expected leading the communities to seek new sinks. Among the different processes suggested we chose to focus on the transport of microplastics from the surface to deeper layers of the ocean via phytoplankton aggregates that constitute most of the sinking flux. Interactions between microplastics and aggregates were studied by building a new device: the flow-through roller tank that mimics the behaviour of laboratory made aggregates sinking through a dense layer of microplastics. Three types of aggregates formed from two different algae species (the diatom Chaetoceros neogracile, the cryptophyte Rhodomonas salina and a mix) were used as model. With their frustule made of biogenic silica which is denser than the organic matter, diatom aggregates sunk faster than R. sauna aggregates. Diatom aggregates were on average bigger and stickier while aggregates from R. sauna were smaller and more fragile. With higher concentrations measured in R. saline aggregates, all model-aggregates incorporated and concentrated microplastics, substantially increasing the microplastic sinking rates from tenths to hundreds of metres per day. Our results clearly show that marine aggregates can be an efficient sink for microplastics by influencing their vertical distribution in the water column. Furthermore, despite the high plastic concentrations tested, our study opens new questions regarding the impact of plastics on sedimentation fluxes in oceans. As an effect of microplastic incorporation, the sinking rates of diatom aggregates strongly decreased meanwhile the sinking rates of cryptophyte aggregates increased.
Published: 2015
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29. The importance of water column processes on the dissolution properties of biogenic silica in deep-sea sediments I. Solubility

Author: David J. DeMaster, Lydie Corrin, Paul Tréguer, Olivier Ragueneau, and Morgane Gallinari
Subjects: chemistry.chemical_compound, chemistry, Geochemistry and Petrology, Silicate minerals, Sediment trap, Mineralogy, Sediment, Silicic acid, Solubility, Biogenic silica, Dissolution, Geology, Diagenesis
Abstract: Flow-through experiments have been performed to study the thermodynamics of biogenic silica (opal) dissolution in deep-sea sediments. They were applied for the first time on sediment from the Southern Ocean Van Cappellen and Qiu 1997a , Van Cappellen and Qiu 1997b We have extended the use of these experiments to other deep-sea settings, thereby covering a wide range of in situ silicic acid asymptotic concentrations (Casympt; 200 to 900 μmol/L) and biogenic opal content (BSi; 0.5 to 80%). Performing these experiments under in situ bottom temperatures allows for the comparison between experimental apparent solubilities and Casympt concentrations. Low values of BSi apparent solubilities have been measured in the deepest sections of the multicores collected in the northeast Atlantic (229 μmol/L) and in the equatorial Pacific (505 μmol/L). They are only 10 to 20% higher than the in situ Casympt concentrations. This demonstrates a clear control of pore water silicic acid concentrations by the in situ apparent solubility of the BSi, i.e., the solubility of BSi within a complex sedimentary matrix that includes important quantities of silicate minerals. In regions where the percentage detrital/percentage biogenic ratio is low, the apparent solubility of the biogenic silica is close to that of in situ biogenic silica. In the opposite case, when the percentage detrital/percentage biogenic ratio is high, reprecipitation reactions induce strong interference on the dissolution properties of the opal, both in situ and in flow-through experiments. In such a sedimentary matrix, it is important to determine the appropriate opal solubility to be used in early diagenetic models, i.e., the solubility of the biogenic silica just before deposition on the seabed. This has been achieved by performing flow-through experiments on sediment trap material from the north Atlantic site. Comparison of apparent biogenic silica solubility measured by flow-through experiments and the silicic acid concentrations measured in the cups of the sediment traps suggested that the solubility of biogenic silica that reaches the sediment-water interface is not unique and varies spatially and temporally. In fact, it is the degree of coupling between surface waters and the sediment-water interface that will control the aging of biogenic silica in the water column and hence the dissolution properties of the biogenic silica deposited at the sediment-water interface. All these results call for a strong improvement of biogenic silica early diagenetic models that should include not only a reprecipitation term that takes into account interaction with silicate minerals but also the existence of several phases of biogenic silica and thus that should operate in a non-steady-state mode to account for seasonal variations in the quality of deposited biogenic silica.
Published: 2002
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30. Not all calcite ballast is created equal: differing effects of foraminiferan and coccolith calcite on the formation and sinking of aggregates

Author: Morgane Gallinari, K. Schmidt, C. L. De La Rocha, Giuseppe Cortese, Faculty of Mathematics and Natural Sciences, University of Groningen [Groningen], Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), GNS Science [Lower Hutt], GNS Science, European Project: 264933,EC:FP7:ENV,FP7-ENV-2010,EURO-BASIN(2010), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Ballast, 0106 biological sciences, 010504 meteorology & atmospheric sciences, lcsh:Life, Mineralogy, REMINERALIZATION, SEDIMENT, Deep sea, 01 natural sciences, Sink (geography), Coccolith, chemistry.chemical_compound, lcsh:QH540-549.5, PARTICLES, RATES, 14. Life underwater, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Earth-Surface Processes, Marine snow, Emiliania huxleyi, ATLANTIC-OCEAN, 0105 earth and related environmental sciences, Calcite, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, geography, geography.geographical_feature_category, biology, ACL, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, VELOCITY, biology.organism_classification, MARINE SNOW, lcsh:Geology, lcsh:QH501-531, Calcium carbonate, chemistry, EMILIANIA-HUXLEYI, lcsh:Ecology, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, ZOOPLANKTON FECAL PELLETS, Geology
Abstract: Correlation between particulate organic carbon (POC) and calcium carbonate sinking through the deep ocean has led to the idea that ballast provided by calcium carbonate is important for the export of POC from the surface ocean. While this idea is certainly to some extent true, it is worth considering in more nuance, for example, examining the different effects on the aggregation and sinking of POC of small, non-sinking calcite particles like coccoliths and large, rapidly sinking calcite like planktonic foraminiferan tests. We have done that here in a simple experiment carried out in roller tanks that allow particles to sink continuously without being impeded by container walls. Coccoliths were efficiently incorporated into aggregates that formed during the experiment, increasing their sinking speed compared to similarly sized aggregates lacking added calcite ballast. The foraminiferan tests, which sank as fast as 700 m d−1, became associated with only very minor amounts of POC. In addition, when they collided with other, larger, foraminferan-less aggregates, they fragmented them into two smaller, more slowly sinking aggregates. While these effects were certainly exaggerated within the confines of the roller tanks, they clearly demonstrate that calcium carbonate ballast is not just calcium carbonate ballast- different forms of calcium carbonate ballast have notably different effects on POC aggregation, sinking, and export.
Published: 2014
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31. The benthic silica cycle in the Northeast Atlantic: annual mass balance, seasonality, and importance of non-steady-state processes for the early diagenesis of biogenic opal in deep-sea sediments

Author: Richard S. Lampitt, Olivier Ragueneau, A Hauvespre, Sibylle Grandel, Per O. J. Hall, A Tengberg, Rob Witbaard, Lydie Corrin, Dirk Rickert, Henrik Stahl, and Morgane Gallinari
Subjects: geography, geography.geographical_feature_category, Abyssal plain, Sediment, Geology, Aquatic Science, Biogenic silica, Diagenesis, Oceanography, Benthic zone, Sediment–water interface, Sediment trap, Porcupine Abyssal Plain
Abstract: Within the framework of the EU-funded BENGAL programme, the effects of seasonality on biogenic silica early diagenesis have been studied at the Porcupine Abyssal Plain (PAP), an abyssal locality located in the northeast Atlantic Ocean. Nine cruises were carried out between August 1996 and August 1998. Silicic acid (DSi) increased downward from 46.2 to 213 μM (mean of 27 profiles). Biogenic silica (BSi) decreased from ca. 2% near the sediment–water interface to
Published: 2001
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32. Enhanced rates of particulate organic matter remineralization by microzooplankton are diminished by added ballast minerals

Author: Morgane Gallinari, F. A. C. Le Moigne, C. L. De La Rocha, E. Laurenceau, National Oceanography Centre [Southampton] (NOC), University of Southampton, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), European Project: 264933,EC:FP7:ENV,FP7-ENV-2010,EURO-BASIN(2010), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut méditerranéen d'océanologie (MIO), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), INL - Chimie et Nanobiotechnologies (INL - C&N), Institut des Nanotechnologies de Lyon (INL), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École Centrale de Lyon (ECL), Université de Lyon, Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Lyon (ECL), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Toulon (UTLN)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Universitaire Européen de la Mer (IUEM), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Inorganic chemistry, lcsh:Life, 01 natural sciences, chemistry.chemical_compound, Water column, lcsh:QH540-549.5, Dissolved organic carbon, Ammonium, Organic matter, ComputingMilieux_MISCELLANEOUS, Ecology, Evolution, Behavior and Systematics, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Earth-Surface Processes, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, chemistry.chemical_classification, Calcite, Remineralisation, 010604 marine biology & hydrobiology, lcsh:QE1-996.5, Particulates, Phosphate, 6. Clean water, lcsh:Geology, lcsh:QH501-531, chemistry, Environmental chemistry, lcsh:Ecology
Abstract: To examine the potentially competing influences of microzooplankton and calcite mineral ballast on organic matter remineralization, we incubated diatoms in darkness in rolling tanks with and without added calcite minerals (coccoliths) and microzooplankton (rotifers). Concentrations of particulate organic matter (POM in suspension or in aggregates), of dissolved organic matter (DOM), and of dissolved inorganic nutrients were monitored over 8 days. The presence of rotifers enhanced the remineralization of ammonium and phosphate, but not dissolved silicon, from the biogenic particulate matter, up to 40% of which became incorporated into aggregates early in the experiment. Added calcite resulted in rates of excretion of ammonium and phosphate by rotifers that were depressed by 67% and 36%, respectively, demonstrating the potential for minerals to inhibit the destruction of POM by zooplankton in the water column. Lastly, the presence of the rotifers and added calcite minerals resulted in a more rapid initial rate of aggregation, although not a greater overall amount of aggregation during the experiment.
Published: 2013
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33. A benthic Si mass balance on the Congo margin: Origin of the 4000 m DSi anomaly and implications for the transfer of Si from land to ocean

Author: François Baurand, Alexis Khripounoff, Morgane Gallinari, Aurore Regaudie-de-Gioux, Olivier Ragueneau, Annick Vangriesheim, Brivaëla Moriceau, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Mediterrani d'Estudis Avancats (IMEDEA), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC)-Universidad de las Islas Baleares (UIB), Laboratoire Environnement Profond (LEP), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER), Si-WEBS RTN (HPRN-CT-2002-00218), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Etudes des Ecosystèmes Profonds (EEP), and Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Mineralogy, Biogenic silica, Oceanography, 01 natural sciences, chemistry.chemical_compound, Flux (metallurgy), Organic matter, 14. Life underwater, Silicic acid, 0105 earth and related environmental sciences, chemistry.chemical_classification, geography, geography.geographical_feature_category, Continental shelf, 010604 marine biology & hydrobiology, Pelagic zone, Continental margin, Sedimentation, Preservation, chemistry, Congo, 13. Climate action, Benthic zone, [SDE]Environmental Sciences, Geology, Dissolution
Abstract: 11 pages, 6 figures, 3 tables.-- Article in press., To elucidate the origin of the silicic acid (DSi) anomaly observed along the 4000 isobath on the Congo margin, we have established a benthic Si mass balance and performed direct measurements of biogenic silica (bSiO2) dissolution in the deep waters and in the sediments. Results strongly suggest that the anomaly originates from the sediments; the intensity of DSi recycling is consistent with the degradation of organic matter, as observed from Si:O2 ratios in the benthic fluxes compared to that ratio observed in the anomalies. Strong imbalances, observed in both the Si and C mass balances, suggest that the biogenic matter that degrades and dissolves in these sediments near 4000 m does not come from pelagic sedimentation. It is probably not coming also from the deep channel, because observations were similar in the deep channel vicinity (site D) and further south, far from its influence (site C). The composition of the sediments, with an Si:C ratio close to that observed on continental shelves, suggests that this matter is coming from downslope transport. A first estimate of the magnitude of this flux at global scale, close to 12 T mol Si yr−1, suggests that it may be an important path for transferring Si from land to ocean., This study has been partly funded through the Si-WEBS RTN (HPRN-CT-2002-00218) and the European Commission is greatly acknowledged.
Published: 2009
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34. Importance of particle formation to reconstructed water column biogenic silica fluxes

Author: Brivaëla Moriceau, Olivier Ragueneau, Karline Soetaert, and Morgane Gallinari
Subjects: 0106 biological sciences, Atmospheric Science, Global and Planetary Change, 010504 meteorology & atmospheric sciences, Frustule, biology, 010604 marine biology & hydrobiology, Pellets, Mineralogy, Biogenic silica, biology.organism_classification, 01 natural sciences, Oceanography, Water column, Diatom, Environmental Chemistry, Particle, 14. Life underwater, Surface layer, Dissolution, 0105 earth and related environmental sciences, General Environmental Science
Abstract: The particles sinking out of the ocean's surface layer are made up of a mixture of living and dead algal cells, fecal pellets, and aggregates, while the parameters used to describe the behavior of biogenic silica (bSiO2) in today's models are experimentally determined on freely suspended diatoms (FC). In a simple advection-reaction model we combine sinking rates of FC, zooplankton fecal pellets, and aggregates with recent measurements of bSiO2 dissolution to reconstruct theoretical downward profiles of bSiO2 fluxes at eight sites in the world ocean. Statistical analyses showed that sinking and dissolution parameters for two pools of bSiO2 are required to model particle fluxes accurately. The two-pool model results confirm the importance of seasonality for particle formation and its connection to the percentage of the bSiO2 production that reaches the seafloor. The depth of bSiO2 recycling appears to be influenced more by particle formation than by dissolution rates of bSiO2 or the ballast effect of the dense diatom frustules.
Published: 2007
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35. Net and gross incorporation of nitrogen by marine copepods fed on 15N labelled diatoms: methodology and trophic studies

Author: Dorothée Vincent, Slawyk, G., Stéphane L'Helguen, Géraldine Sarthou, Morgane Gallinari, Laurent Seuront, Sautour, B., Olivier Ragueneau, Laboratoire d’Océanologie et de Géosciences (LOG) - UMR 8187 (LOG), Centre National de la Recherche Scientifique (CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Institut national des sciences de l'Univers (INSU - CNRS), Ecosystèmes Littoraux et Cotiers, Université de Lille, Sciences et Technologies-Centre National de la Recherche Scientifique (CNRS), Adaptation et diversité en milieu marin (AD2M), Station biologique de Roscoff [Roscoff] (SBR), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Brest (UBO), Station Marine de Wimereux, Centre National de la Recherche Scientifique (CNRS), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Nord]), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Institut national des sciences de l'Univers (INSU - CNRS)-Université du Littoral Côte d'Opale (ULCO)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDU]Sciences of the Universe [physics], ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2007

36. Grazing-induced changes in cell wall silicification in a marine diatom

Author: Sophie Chollet, Morgane Gallinari, Philippe Pondaven, Géraldine Sarthou, Frédéric Jean, Sabine Schultes, Eva Bucciarelli, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), European Project, and Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 0106 biological sciences, 010504 meteorology & atmospheric sciences, Frustule, copepods, DEFENSE, DAPHNIA, Marine Biology, 01 natural sciences, Microbiology, Grazing pressure, diatoms, Cell wall, Copepoda, CARBON, SCENEDESMUS, OCEAN, Cell Wall, Grazing, Botany, Animals, Ecosystem, 14. Life underwater, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, Marine biology, biology, Ecology, herbivory, 010604 marine biology & hydrobiology, Aquatic ecosystem, silicification BIOGENIC SILICA, fungi, biology.organism_classification, Silicon Dioxide, Adaptation, Physiological, Diatom, 13. Climate action, Predatory Behavior, induced defense, MORPHOLOGY, GROWTH, BACILLARIOPHYCEAE, ALGA
Abstract: International audience; In aquatic environments, diatoms (Bacillariophyceae) constitute a central group of microalgae which contribute to about 40% of the oceanic primary production. Diatoms have an absolute requirement for silicon to build-up their silicified cell wall in the form of two shells (the frustule). To date, changes in diatom cell wall silicification have been only studied in response to changes in the growth environment, with consistent increase in diatom silica content when specific growth rates decrease under nutrient or light limitations. Here, we report the first evidence for grazing-induced changes in cell wall silicification in a marine diatom. Cells grown in preconditioned media that had contained both diatoms and herbivores are significantly more silicified than diatoms grown in media that have contained diatoms alone or starved herbivores. These observations suggest that grazing-induced increase in cell wall silicification can be viewed as an adaptive reaction in habitats with variable grazing pressure, and demonstrate that silicification in diatoms is not only a constitutive mechanical protection for the cell, but also a phenotypically plastic trait modulated by grazing. In turn, our results corroborate the idea that plant-herbivore interactions, beyond grazing sensu stricto, contribute to drive ecosystem structure and biogeochemical cycles in the ocean.
Published: 2007
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37. Calibration of biogenic silica (BSi) as a paleo productivity proxy: towards a mechanistic understanding of BSi dissolution/preservation, and Si/ decoupling in the world ocean

Author: Olivier Ragueneau, Pascal Claquin, Corrin, L., Demaster, D., Dittert Nicolas, Morgane Gallinari, Christoph Heinze, Véronique Martin-Jézéquel, Aude Leynaert, Brivaëla Moriceau, Philippe Pondaven, Philippe van Cappellen, Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Centre National de la Recherche Scientifique (CNRS)-Université des Antilles (UA)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Sorbonne Université (SU)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU), Department of MEAS, North Carolina State University [Raleigh] (NC State), University of North Carolina System (UNC)-University of North Carolina System (UNC), Geophysical Institute [Bergen] (GFI / BiU), University of Bergen (UiB), LIttoral ENvironnement et Sociétés - UMRi 7266 (LIENSs), Université de La Rochelle (ULR)-Centre National de la Recherche Scientifique (CNRS), School of Earth and Atmospheric Sciences [Atlanta], and Georgia Institute of Technology [Atlanta]
Subjects: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2003

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