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52. Impact of dust addition on Mediterranean plankton communities under present and future conditions of pH and temperature: an experimental overview

Author

Gazeau, Frédéric, Ridame, Céline, Van Wambeke, France, Alliouane, Samir, Stolpe, Christian, Irisson, Jean-Olivier, Marro, Sophie, Grisoni, Jean-Michel, De Liège, Guillaume, Nunige, Sandra, Djaoudi, Kahina, Pulido-Villena, Elvira, Dinasquet, Julie, Obernosterer, Ingrid, Catala, Philippe, Guieu, Cécile, 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), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), 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)), 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), 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), Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Scripps Institution of Oceanography (SIO - UC San Diego), University of California [San Diego] (UC San Diego), University of California (UC)-University of California (UC), 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), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), 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 de Paris (UP)-École normale supérieure - Paris (ENS Paris), 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 de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), 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 de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Scripps Institution of Oceanography (SIO), University of California-University of California, and Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [SDE]Environmental Sciences
Abstract

In low-nutrient low-chlorophyll areas, such as the Mediterranean Sea, atmospheric fluxes represent a considerable external source of nutrients likely supporting primary production, especially during periods of stratification. These areas are expected to expand in the future due to lower nutrient supply from sub-surface waters caused by climate-driven enhanced stratification, likely further increasing the role of atmospheric deposition as a source of new nutrients to surface waters. Whether plankton communities will react differently to dust deposition in a warmer and acidified environment remains; however, an open question. The potential impact of dust deposition both in present and future climate conditions was investigated in three perturbation experiments in the open Mediterranean Sea. Climate reactors (300 L) were filled with surface water collected in the Tyrrhenian Sea, Ionian Sea and in the Algerian basin during a cruise conducted in the frame of the PEACETIME project in May–June 2017. The experiments comprised two unmodified control tanks, two tanks enriched with a Saharan dust analogue and two tanks enriched with the dust analogue and maintained under warmer (+3 ∘C) and acidified (−0.3 pH unit) conditions. Samples for the analysis of an extensive number of biogeochemical parameters and processes were taken over the duration (3–4 d) of the experiments. Dust addition led to a rapid release of nitrate and phosphate, however, nitrate inputs were much higher than phosphate. Our results showed that the impacts of Saharan dust deposition in three different basins of the open northwestern Mediterranean Sea are at least as strong as those observed previously, all performed in coastal waters. The effects of dust deposition on biological stocks were different for the three investigated stations and could not be attributed to differences in their degree of oligotrophy but rather to the initial metabolic state of the community. Ocean acidification and warming did not drastically modify the composition of the autotrophic assemblage, with all groups positively impacted by warming and acidification. Although autotrophic biomass was more positively impacted than heterotrophic biomass under future environmental conditions, a stronger impact of warming and acidification on mineralization processes suggests a decreased capacity of Mediterranean surface plankton communities to sequester atmospheric CO2 following the deposition of atmospheric particles.

Published
2021
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53. N2 fixation in the Mediterranean Sea related to the composition of the diazotrophic community, and impact of dust under present and future environmental conditions

Author

Ridame, Céline, Dinasquet, Julie, Hallstrøm, Søren, Bigeard, Estelle, Riemann, Lasse, van Wambeke, France, Bressac, Matthieu, Pulido-Villena, Elvira, Taillandier, Vincent, Gazeau, Frédéric, Tovar-Sánchez, Antonio, Baudoux, Anne-Claire, Guieu, Cécile, Cycles biogéochimiques marins : processus et perturbations (CYBIOM), 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)), 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), Scripps Institution of Oceanography (SIO - UC San Diego), University of California [San Diego] (UC San Diego), University of California (UC)-University of California (UC), 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), University of Copenhagen = Københavns Universitet (UCPH), 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), 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 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), Institute of Marine Sciences of Andalusia (ICMAN), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Sorbonne Université (SU), Centre National de la Recherche Scientifique (CNRS), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), 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 de Paris (UP)-École normale supérieure - Paris (ENS Paris), 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 de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Scripps Institution of Oceanography (SIO), University of California-University of California, Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire océanologique de Banyuls (OOB), University of Copenhagen = Københavns Universitet (KU), 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), PEACETIME project (http://peacetime-project.org), GEOTRACES, Centre National de la Recherche Scientifique (France), European Commission, Danish Council for Independent Research, and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU]Sciences of the Universe [physics], [SDE]Environmental Sciences, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract

N2 fixation rates were measured in the 0-1000ĝ€¯m layer at 13 stations located in the open western and central Mediterranean Sea (MS) during the PEACETIME cruise (late spring 2017). While the spatial variability in N2 fixation was not related to Fe, P nor N stocks, the surface composition of the diazotrophic community indicated a strong longitudinal gradient increasing eastward for the relative abundance of non-cyanobacterial diazotrophs (NCDs) (mainly 3-Proteobacteria) and conversely decreasing eastward for photo-heterotrophic group A (UCYN-A) (mainly UCYN-A1 and UCYN-A3), as did N2 fixation rates. UCYN-A4 and UCYN-A3 were identified for the first time in the MS. The westernmost station influenced by Atlantic waters and characterized by highest stocks of N and P displayed a patchy distribution of diazotrophic activity with an exceptionally high rate in the euphotic layer of 72.1ĝ€¯nmolNL-1d-1, which could support up to 19ĝ€¯% of primary production. At this station at 1ĝ€¯%PAR (photosynthetically available radiation) depth, UCYN-A4 represented up to 94ĝ€¯% of the diazotrophic community. These in situ observations of greater relative abundance of UCYN-A at stations with higher nutrient concentrations and dominance of NCDs at more oligotrophic stations suggest that nutrient conditions-even in the nanomolar range-may determine the composition of diazotrophic communities and in turn N2 fixation rates. The impact of Saharan dust deposition on N2 fixation and diazotrophic communities was also investigated, under present and future projected conditions of temperature and pH during short-Term (3-4ĝ€¯d) experiments at three stations. New nutrients from simulated dust deposition triggered a significant stimulation of N2 fixation (from 41ĝ€¯% to 565ĝ€¯%). The strongest increase in N2 fixation was observed at the stations dominated by NCDs and did not lead on this short timescale to changes in the diazotrophic community composition. Under projected future conditions, N2 fixation was either increased or unchanged; in that later case this was probably due to a too-low nutrient bioavailability or an increased grazing pressure. The future warming and acidification likely benefited NCDs (Pseudomonas) and UCYN-A2, while disadvantaged UCYN-A3 without knowing which effect (alone or in combination) is the driver, especially since we do not know the temperature optima of these species not yet cultivated as well as the effect of acidification., This study is a contribution to the PEACETIME project (http://peacetime-project.org, last access: 17 January 2022), a joint initiative of the MERMEX and ChArMEx components supported by the CNRS-INSU, IFREMER, CEA and Météo-France as part of the program MISTRALS coordinated by the INSU. PEACETIME was endorsed as a process study by GEOTRACES. Julie Dinasquet was funded by a Marie Curie Actions International Outgoing Fellowship (PIOF-GA-2013-629378). Søren Hallstrøm and Lasse Riemann were funded by grant 6108-00013 from the Danish Council for Independent Research.

Published
2021
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54. Subsurface iron accumulation and rapid aluminum removal in the Mediterranean following African dust deposition

Author

Bressac, Matthieu, primary, Wagener, Thibaut, additional, Leblond, Nathalie, additional, Tovar-Sánchez, Antonio, additional, Ridame, Céline, additional, Taillandier, Vincent, additional, Albani, Samuel, additional, Guasco, Sophie, additional, Dufour, Aurélie, additional, Jacquet, Stéphanie H. M., additional, Dulac, François, additional, Desboeufs, Karine, additional, and Guieu, Cécile, additional

Published
2021
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55. Phosphorus cycling in the upper waters of the Mediterranean Sea (PEACETIME cruise): relative contribution of external and internal sources

Author

Pulido-Villena, Elvira, primary, Desboeufs, Karine, additional, Djaoudi, Kahina, additional, Van Wambeke, France, additional, Barrillon, Stéphanie, additional, Doglioli, Andrea, additional, Petrenko, Anne, additional, Taillandier, Vincent, additional, Fu, Franck, additional, Gaillard, Tiphanie, additional, Guasco, Sophie, additional, Nunige, Sandra, additional, Triquet, Sylvain, additional, and Guieu, Cécile, additional

Published
2021
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56. Quels modes de croissance pour les PME en hypercroissance ?

Author

Chanut-Guieu, Cécile and Guieu, Gilles

Subjects
entreprise, gouvernance, BUS000000, Economics, management stratégique, Business
Abstract

En se fondant sur la notion de paradoxes de Lewis (2000), le chapitre fait l’hypothèse que la combinaison des trois modalités de croissance (interne, externe, conjointe) permet de maintenir les tensions nécessaires à la longévité d’une trajectoire d’hypercroissance. À partir d’une revue de la littérature et de données de terrain (questionnaires et études de cas), les auteurs concluent que les opérations menées par les PME en forte croissance sont l’occasion d’apprendre sur elles-mêmes et de renouveler les rythmes et les compétences acquises. L’utilisation d’un portefeuille de modalités différentes pour croître permet à ces entreprises de se réinventer, et continuer à croître à grande vitesse. La combinaison des opérations de croissance interne, externe et conjointe peut être un moyen pour les PME en hypercroissance de dépasser les paradoxes auxquels elles ont à faire face en continuant à croître par un changement radical et permanent. Based on the notion of paradoxes (Lewis, 2000), the chapter puts the hypothesis that the combination of organic growth, acquisitions and alliances creates tensions that are necessary to maintain a hyper growth trajectory. Thanks to a review of the literature and field data (surveys and case studies), the authors conclude that the operations led by fast growing small businesses are opportunities of learning on their proper behaviour and of renewal of their paces and competences. The use of a set of various modalities of growth helps such firms to re-invent themselves and to continue rapid growth. The combination of organic growth, acquisitions and alliances could be a means for high-growth small businesses to go beyond the paradoxes they have to cope with, because this combination creates radical and permanent changes.

Published
2021

59. Impact of dust addition on the metabolism of Mediterranean plankton communities and carbon export under present and future conditions of pH and temperature

Author

Gazeau, Frédéric, primary, Van Wambeke, France, additional, Marañón, Emilio, additional, Pérez-Lorenzo, Maria, additional, Alliouane, Samir, additional, Stolpe, Christian, additional, Blasco, Thierry, additional, Leblond, Nathalie, additional, Zäncker, Birthe, additional, Engel, Anja, additional, Marie, Barbara, additional, Dinasquet, Julie, additional, and Guieu, Cécile, additional

Published
2021
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60. Supplementary material to "Wet deposition in the remote western and central Mediterranean as a source of trace metals to surface seawater"

Author

Desboeufs, Karine, primary, Fu, Franck, additional, Bressac, Matthieu, additional, Tovar-Sánchez, Antonio, additional, Triquet, Sylvain, additional, Doussin, Jean-François, additional, Giorio, Chiara, additional, Chazette, Patrick, additional, Disnaquet, Julie, additional, Feron, Anaïs, additional, Formenti, Paola, additional, Maisonneuve, Franck, additional, Rodríguez-Romero, Araceli, additional, Zapf, Pascal, additional, Dulac, François, additional, and Guieu, Cécile, additional

Published
2021
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61. Wet deposition in the remote western and central Mediterranean as a source of trace metals to surface seawater

Author

Desboeufs, Karine, primary, Fu, Franck, additional, Bressac, Matthieu, additional, Tovar-Sánchez, Antonio, additional, Triquet, Sylvain, additional, Doussin, Jean-François, additional, Giorio, Chiara, additional, Chazette, Patrick, additional, Disnaquet, Julie, additional, Feron, Anaïs, additional, Formenti, Paola, additional, Maisonneuve, Franck, additional, Rodríguez-Romero, Araceli, additional, Zapf, Pascal, additional, Dulac, François, additional, and Guieu, Cécile, additional

Published
2021
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62. Supplementary material to "N2 fixation in the Mediterranean Sea related to the composition of the diazotrophic community, and impact of dust under present and future environmental conditions"

Author

Ridame, Céline, primary, Dinasquet, Julie, additional, Hallstrøm, Søren, additional, Bigeard, Estelle, additional, Riemann, Lasse, additional, Van Wambeke, France, additional, Bressac, Matthieu, additional, Pulido-Villena, Elvira, additional, Taillandier, Vincent, additional, Gazeau, Frederic, additional, Tover-Sanchez, Antonio, additional, Baudoux, Anne-Claire, additional, and Guieu, Cécile, additional

Published
2021
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63. N2 fixation in the Mediterranean Sea related to the composition of the diazotrophic community, and impact of dust under present and future environmental conditions

Author

Ridame, Céline, primary, Dinasquet, Julie, additional, Hallstrøm, Søren, additional, Bigeard, Estelle, additional, Riemann, Lasse, additional, Van Wambeke, France, additional, Bressac, Matthieu, additional, Pulido-Villena, Elvira, additional, Taillandier, Vincent, additional, Gazeau, Frederic, additional, Tover-Sanchez, Antonio, additional, Baudoux, Anne-Claire, additional, and Guieu, Cécile, additional

Published
2021
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64. Contrasted release of insoluble elements (Fe, Al, rare earth elements, Th, Pa) after dust deposition in seawater: a tank experiment approach

Author

Roy-Barman, Matthieu, Foliot, Lorna, Douville, Eric, Leblond, Nathalie, Gazeau, Frédéric, Bressac, Matthieu, Wagener, Thibaut, Ridame, Céline, Desboeufs, Karine, Guieu, Cécile, Géochimie Des Impacts (GEDI), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), 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), Géochrononologie Traceurs Archéométrie (GEOTRAC), Institut de la Mer de Villefranche (IMEV), Sorbonne Université (SU)-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), University of Tasmania [Hobart, Australia] (UTAS), 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), Cycles biogéochimiques marins : processus et perturbations (CYBIOM), 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)), 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), Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), 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), 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 de Recherche pour le Développement (IRD)-Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Toulon (UTLN), Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), 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 de Paris (UP)-École normale supérieure - Paris (ENS Paris), 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 de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), 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 de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)

Subjects
[SDE]Environmental Sciences
Abstract

Lithogenic elements such as aluminum (Al), iron (Fe), rare earth elements (REEs), thorium (232Th and 230Th, given as Th) and protactinium (Pa) are often assumed to be insoluble. In this study, their dissolution from Saharan dust reaching Mediterranean seawater was studied through tank experiments over 3 to 4 d under controlled conditions including controls without dust addition as well as dust seeding under present and future climate conditions (+3 ∘C and −0.3 pH). Unfiltered surface seawater from three oligotrophic regions (Tyrrhenian Sea, Ionian Sea and Algerian Basin) were used. The maximum dissolution was low for all seeding experiments: less than 0.3 % for Fe, 1 % for 232Th and Al, about 2 %–5 % for REEs and less than 6 % for Pa. Different behaviors were observed: dissolved Al increased until the end of the experiments, Fe did not dissolve significantly, and Th and light REEs were scavenged back on particles after a fast initial release. The constant 230Th/232Th ratio during the scavenging phase suggests that there is little or no further dissolution after the initial Th release. Quite unexpectedly, comparison of present and future conditions indicates that changes in temperature and/or pH influence the release of Th and REEs in seawater, leading to lower Th release and a higher light REE release under increased greenhouse conditions.

Published
2021
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66. Mediterranean nascent sea spray organic aerosol and relationships with seawater biogeochemistry

Author

Freney, Evelyn, primary, Sellegri, Karine, additional, Nicosia, Alessia, additional, Williams, Leah R., additional, Rinaldi, Matteo, additional, Trueblood, Jonathan T., additional, Prévôt, André S. H., additional, Thyssen, Melilotus, additional, Grégori, Gérald, additional, Haëntjens, Nils, additional, Dinasquet, Julie, additional, Obernosterer, Ingrid, additional, Van Wambeke, France, additional, Engel, Anja, additional, Zäncker, Birthe, additional, Desboeufs, Karine, additional, Asmi, Eija, additional, Timonen, Hilkka, additional, and Guieu, Cécile, additional

Published
2021
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67. Changing atmospheric acidity as a modulator of nutrient deposition and ocean biogeochemistry

Author

Baker, Alex R., primary, Kanakidou, Maria, additional, Nenes, Athanasios, additional, Myriokefalitakis, Stelios, additional, Croot, Peter L., additional, Duce, Robert A., additional, Gao, Yuan, additional, Guieu, Cécile, additional, Ito, Akinori, additional, Jickells, Tim D., additional, Mahowald, Natalie M., additional, Middag, Rob, additional, Perron, Morgane M. G., additional, Sarin, Manmohan M., additional, Shelley, Rachel, additional, and Turner, David R., additional

Published
2021
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70. 'Tell me what you read, I'll tell you what you are'. Relationship between Monitoring and Strategic Orientation

Author

Chanut-Guieu, Cécile, Laboratoire d'économie et de sociologie du travail (LEST), and Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Competitive Intelligence, Monitoring, Strategic orientation, [SHS.GESTION]Humanities and Social Sciences/Business administration, Organizational Strategy, Organizational Environment
Abstract

International audience; This research aimed to investigate the relationship between how an organization monitors its external environment and defines its strategic orientation. These two constructs are assessed through the perception of professionals related to monitoring activities in their organizations. The approach chosen is quantitative, using the survey as research method. Data are analyzed by using descriptive statistics, non-parametric and multivariate analysis. The results indicate a relationship between external monitoring and strategic orientation: the formal search for information stood out more in analytical and prospector organizations and informal search, in reactive and defensive ones.

Published
2020

71. Wet deposition in the remote western and central Mediterranean as a source of trace metals to surface seawater

Author

Desboeufs, Karine, Fu, Franck, Bressac, Matthieu, Tovar-sánchez, Antonio, Triquet, Sylvain, Doussin, Jean-françois, Giorio, Chiara, Chazette, Patrick, Disnaquet, Julie, Feron, Anaïs, Formenti, Paola, Maisonneuve, Franck, Rodríguez-romero, Araceli, Zapf, Pascal, Dulac, François, Guieu, Cécile, Desboeufs, Karine, Fu, Franck, Bressac, Matthieu, Tovar-sánchez, Antonio, Triquet, Sylvain, Doussin, Jean-françois, Giorio, Chiara, Chazette, Patrick, Disnaquet, Julie, Feron, Anaïs, Formenti, Paola, Maisonneuve, Franck, Rodríguez-romero, Araceli, Zapf, Pascal, Dulac, François, and Guieu, Cécile

Abstract

his study reports the only recent characterisation of two contrasted wet deposition events collected during the PEACETIME cruise in the Mediterranean open seawater, and their impact on trace metals (TMS) marine stocks. Rain samples were analysed for Al, 12 trace metals (TMs hereafter, including Co, Cd, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Ti, V and Zn) and nutrients (N, P, DOC) concentrations. The first rain sample collected in the Ionian Sea (rain ION) was a wet typical regional background deposition event whereas the second rain collected in the Algerian Basin (rain FAST) was a Saharan dust wet deposition. The concentrations of TMs in the two rain samples were significantly lower compared to concentrations in rains collected at coastal sites reported in the literature, suggesting either less anthropogenic influence in the remote Mediterranean environment, or decreased emissions during the last decades in the Mediterranean Sea. The TMs inventories in the surface microlayer and mixed layer (0–20 m) at ION and FAST stations before and after the events, compared to atmospheric fluxes, showed that the atmospheric inputs were a significant source of particulate TMs for both layers. At the scale of the western and central Mediterranean, the atmospheric inputs were of the same order of magnitude as marine stocks within the ML for dissolved Fe, Co and Zn, underlining the role of the atmosphere in their biogeochemical cycle in the stratified Mediterranean Sea. In case of intense wet dust deposition event, the contribution of atmospheric inputs could be critical for dissolved stocks of the majority of TMs.

Published
2021
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72. Mediterranean nascent sea spray organic aerosol and relationships with seawater biogeochemistry

Author

Freney, Evelyn, Sellegri, Karine, Nicosia, Alessia, Trueblood, Jonathan T, Rinaldi, Matteo, Williams, Leah R, Prévôt, André Sh, Thyssen, Melilotus, Gregori, Gerald, Haëntjens, Nils, Dinasquet, Julie, Obernosterer, Ingrid, Van Wambeke, France, Engel, Anja, Zancker, Birthe, Desboeufs, Karine, Asmi, Eija, Timmonen, Hilka, Guieu, Cécile, Freney, Evelyn, Sellegri, Karine, Nicosia, Alessia, Trueblood, Jonathan T, Rinaldi, Matteo, Williams, Leah R, Prévôt, André Sh, Thyssen, Melilotus, Gregori, Gerald, Haëntjens, Nils, Dinasquet, Julie, Obernosterer, Ingrid, Van Wambeke, France, Engel, Anja, Zancker, Birthe, Desboeufs, Karine, Asmi, Eija, Timmonen, Hilka, and Guieu, Cécile

Abstract

The organic mass fraction from sea spray aerosol (SSA) is currently a subject of intense research. The majority of this research is dedicated to measurements in ambient air, although recently a small number of studies have additionally focused on nascent sea spray aerosol. This work presents measurements collected during a five-week cruise in May and June 2017 in the central and western Mediterranean Sea, an oligotrophic marine region with low phytoplankton biomass. Surface seawater was continuously pumped into a bubble bursting apparatus to generate nascent sea spray aerosol. Size distributions were measured with a differential mobility particle sizer (DMPS). Chemical characterization of the submicron aerosol was performed with a time of flight aerosol chemical speciation monitor (ToF-ACSM) operating with a 15-minute time resolution, and with filter-based chemical analysis on a daily basis. Using a positive matrix factorization analysis, the ToF-ACSM non-refractory organic matter (OMNR) was separated into four different organic aerosols types which were identified as primary OA (POANR), oxidized OA (OOANR), a methanesulfonic acid type OA (MSA-OANR) and a mixed OA (MOANR). In parallel, surface seawater biogeochemical properties were monitored providing information on phytoplankton cell abundance and seawater particulate organic carbon (one-hour time resolution), and seawater surface microlayer (SML) dissolved organic carbon (DOC) (on a daily basis). Statistically robust correlations (for n > 500) were found between MOANR and nano phytoplankton cell abundance, as well as between POANR, OOANR, and particulate organic carbon (POC). Filter-based analysis of the submicron SSA showed that the non-refractory organic mass represented only 13 ± 3 % of the total organic mass, which represents 22 ± 6 % of the total sea spray mass. Parameterizations of the contributions of different types of organics to the submicron nascent sea spray aerosol are proposed as a function of the s

Published
2021
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73. Impact of dust addition on the microbial food web under present and future conditions of pH and temperature

Author

Dinasquet, Julie, Bigeard, Estelle, Gazeau, Frédéric, Azam, Farooq, Guieu, Cécile, Marañón, Emilio, Ridame, Céline, Van Wambeke, France, Obernosterer, Ingrid, Baudoux, Anne-claire, Dinasquet, Julie, Bigeard, Estelle, Gazeau, Frédéric, Azam, Farooq, Guieu, Cécile, Marañón, Emilio, Ridame, Céline, Van Wambeke, France, Obernosterer, Ingrid, and Baudoux, Anne-claire

Abstract

In the oligotrophic waters of the Mediterranean Sea, during the stratification period, the microbial loop relies on pulsed inputs of nutrients through atmospheric deposition of aerosols from both natural (Saharan dust) and anthropogenic origins. While the influence of dust deposition on microbial processes and community composition is still not fully constrained, the extent to which future environmental conditions will affect dust inputs and the microbial response is not known. The impact of atmospheric wet dust deposition was studied both under present and future (warming and acidification) environmental conditions through experiments in 300 L climate reactors. Three dust addition experiments were performed with surface seawater collected from the Tyrrhenian Sea, Ionian Sea and Algerian basin in the Western Mediterranean Sea during the PEACETIME cruise in May–June 2017. Top-down controls on bacteria, viral processes and community, as well as microbial community structure (16S and 18S rDNA amplicon sequencing) were followed over the 3–4 days experiments. Different microbial and viral responses to dust were observed rapidly after addition and were most of the time higher when combined to future environmental conditions. The input of nutrients and trace metals changed the microbial ecosystem from bottom-up limited to a top-down controlled bacterial community, likely from grazing and induced lysogeny. The composition of mixotrophic microeukaryotes and phototrophic prokaryotes was also altered. Overall, these results suggest that the effect of dust deposition on the microbial loop is dependent on the initial microbial assemblage and metabolic state of the tested water, and that predicted warming, and acidification will intensify these responses, affecting food web processes and biogeochemical cycles.

Published
2021
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74. Subsurface iron accumulation and rapid aluminum removal in the Mediterranean following African dust deposition

Author

Bressac, M, Wagener, T, Leblond, N, Tovar-Sánchez, A, Ridame, C, Taillandier, V, Albani, S, Guasco, S, Dufour, A, Jacquet, S, Dulac, F, Desboeufs, K, Guieu, C, Bressac, Matthieu, Wagener, Thibaut, Leblond, Nathalie, Tovar-Sánchez, Antonio, Ridame, Céline, Taillandier, Vincent, Albani, Samuel, Guasco, Sophie, Dufour, Aurélie, Jacquet, Stéphanie H. M., Dulac, François, Desboeufs, Karine, Guieu, Cécile, Bressac, M, Wagener, T, Leblond, N, Tovar-Sánchez, A, Ridame, C, Taillandier, V, Albani, S, Guasco, S, Dufour, A, Jacquet, S, Dulac, F, Desboeufs, K, Guieu, C, Bressac, Matthieu, Wagener, Thibaut, Leblond, Nathalie, Tovar-Sánchez, Antonio, Ridame, Céline, Taillandier, Vincent, Albani, Samuel, Guasco, Sophie, Dufour, Aurélie, Jacquet, Stéphanie H. M., Dulac, François, Desboeufs, Karine, and Guieu, Cécile

Abstract

Mineral dust deposition is an important supply mechanism for trace elements in the low-latitude ocean. Our understanding of the controls of such inputs has been mostly built on laboratory and surface ocean studies. The lack of direct observations and the tendency to focus on near-surface waters prevent a comprehensive evaluation of the role of dust in oceanic biogeochemical cycles. In the frame of the PEACETIME project (ProcEss studies at the Air-sEa Interface after dust deposition in the MEditerranean sea), the responses of the aluminum (Al) and iron (Fe) cycles to two dust wet deposition events over the central and western Mediterranean Sea were investigated at a timescale of hours to days using a comprehensive dataset gathering dissolved and suspended particulate concentrations, along with sinking fluxes. Dissolved Al (dAl) removal was dominant over dAl released from dust. The Fe/Al ratio of suspended and sinking particles revealed that biogenic particles, and in particular diatoms, were key in accumulating and exporting Al relative to Fe. By combining these observations with published Al/Si ratios of diatoms, we show that adsorption onto biogenic particles, rather than active uptake, represents the main sink for dAl in Mediterranean waters. In contrast, systematic dissolved Fe (dFe) accumulation occurred in subsurface waters (∼ 100-1000m), while dFe input from dust was only transient in the surface mixed layer. The rapid transfer of dust to depth, the Fe-binding ligand pool in excess to dFe in subsurface (while nearly saturated in surface), and low scavenging rates in this particle-poor depth horizon are all important drivers of this subsurface dFe enrichment. At the annual scale, this previously overlooked mechanism may represent an additional pathway of dFe supply for the surface ocean through diapycnal diffusion and vertical mixing. However, low subsurface dFe concentrations observed at the basin scale (<0.5nmolkg-1) cause us to question the residence time

Published
2021

75. Impact of dust addition on the metabolism of Mediterranean plankton communities and carbon export under present and future conditions of pH and temperature

Author

Gazeau, Frédéric, Van Wambeke, France, Marañón, Emilio, Pérez-Lorenzo, Maria, Alliouane, Samir, Stolpe, Christian, Blasco, Thierry, Leblond, Nathalie, Zäncker, Birthe, Engel, Anja, Marie, Barbara, Dinasquet, Julie, Guieu, Cécile, Gazeau, Frédéric, Van Wambeke, France, Marañón, Emilio, Pérez-Lorenzo, Maria, Alliouane, Samir, Stolpe, Christian, Blasco, Thierry, Leblond, Nathalie, Zäncker, Birthe, Engel, Anja, Marie, Barbara, Dinasquet, Julie, and Guieu, Cécile

Abstract

Although atmospheric dust fluxes from arid as well as human-impacted areas represent a significant source of nutrients to surface waters of the Mediterranean Sea, studies focusing on the evolution of the metabolic balance of the plankton community following a dust deposition event are scarce, and none were conducted in the context of projected future levels of temperature and pH. Moreover, most of the experiments took place in coastal areas. In the framework of the PEACETIME project, three dust-addition perturbation experiments were conducted in 300 L tanks filled with surface seawater collected in the Tyrrhenian Sea (TYR), Ionian Sea (ION) and Algerian basin (FAST) on board the R/V Pourquoi Pas? in late spring 2017. For each experiment, six tanks were used to follow the evolution of chemical and biological stocks, biological activity and particle export. The impacts of a dust deposition event simulated at their surface were followed under present environmental conditions and under a realistic climate change scenario for 2100 (ca. +3 ∘C and −0.3 pH units). The tested waters were all typical of stratified oligotrophic conditions encountered in the open Mediterranean Sea at this period of the year, with low rates of primary production and a metabolic balance towards net heterotrophy. The release of nutrients after dust seeding had very contrasting impacts on the metabolism of the communities, depending on the station investigated. At TYR, the release of new nutrients was followed by a negative impact on both particulate and dissolved 14C-based production rates, while heterotrophic bacterial production strongly increased, driving the community to an even more heterotrophic state. At ION and FAST, the efficiency of organic matter export due to mineral/organic aggregation processes was lower than at TYR and likely related to a lower quantity/age of dissolved organic matter present at the time of the seeding and a smaller production of DOM following dust addition. This wa

Published
2021
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76. Influence of atmospheric deposition on biogeochemical cycles in an oligotrophic ocean system

Author

Van Wambeke, France, Taillandier, Vincent, Deboeufs, Karine, Pullido-villena, Elvira, Dinasquet, Julie, Engel, Anja, Maranon, Emilio, Ridame, Céline, Guieu, Cécile, Van Wambeke, France, Taillandier, Vincent, Deboeufs, Karine, Pullido-villena, Elvira, Dinasquet, Julie, Engel, Anja, Maranon, Emilio, Ridame, Céline, and Guieu, Cécile

Abstract

The surface mixed layer (ML) in the Mediterranean Sea is a well stratified domain characterized by low macro-nutrient and low chlorophyll content, during almost 6 months of the year. Nutrient dynamics in the ML depend on allochthonous inputs, through atmospheric deposition and on biological recycling. Here we characterize the biogeochemical cycling of N in the ML by combining simultaneous in situ measurements of atmospheric deposition, nutrients, hydrological conditions, primary production, heterotrophic prokaryotic production, N2 fixation and leucine aminopeptidase activity. The measurements were conducted along a 4300 km transect across the central and western open Mediterranean Sea in spring 2017. Dry deposition was measured on a continuous basis while two wet deposition events were sampled, one in the Ionian Sea and one in the Algerian basin. Along the transect, N budgets were computed to compare sources and sinks of N in the mixed layer. On average, phytoplankton N demand was 2.9 fold higher (range 1.5–8.1) than heterotrophic prokaryotic N demand. In situ leucine aminopeptidase activity contributed from 14 to 66 % of heterotrophic prokaryotic N demand, and N2 fixation rate represented 1 to 4.5 % of the phytoplankton N demand. Dry atmospheric deposition of inorganic nitrogen, estimated from dry deposition of (nitrate + ammonium) in aerosols, was higher than N2 fixation rates in the ML (on average 4.8 fold). The dry atmospheric input of inorganic N represented a highly variable proportion of biological N demand in the ML, 10–82 % for heterotrophic prokaryotes and 1–30 % for phytoplankton. Stations visited for several days allowed following the evolution of biogeochemical properties in the ML and within the nutrient depleted layers. At the site in the Algerian Basin and on a basis of high frequency sampling of CTD casts before and after a wet dust deposition event, different scenarios were considered to explain a delayed appearance of peaks in dissolved inorganic

Published
2021
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77. A two-component parameterization of marine ice-nucleating particles based on seawater biology and sea spray aerosol measurements in the Mediterranean Sea

Author

Trueblood, Jonathan V., Nicosia, Alessia, Engel, Anja, Zäncker, Birthe, Rinaldi, Matteo, Freney, Evelyn, Thyssen, Melilotus, Obernosterer, Ingrid, Dinasquet, Julie, Belosi, Franco, Tovar-Sánchez, Antonio, Rodriguez-Romero, Araceli, Santachiara, Gianni, Guieu, Cécile, Sellegri, Karine, Trueblood, Jonathan V., Nicosia, Alessia, Engel, Anja, Zäncker, Birthe, Rinaldi, Matteo, Freney, Evelyn, Thyssen, Melilotus, Obernosterer, Ingrid, Dinasquet, Julie, Belosi, Franco, Tovar-Sánchez, Antonio, Rodriguez-Romero, Araceli, Santachiara, Gianni, Guieu, Cécile, and Sellegri, Karine

Abstract

Ice-nucleating particles (INPs) have a large impact on the climate-relevant properties of clouds over the oceans. Studies have shown that sea spray aerosols (SSAs), produced upon bursting of bubbles at the ocean surface, can be an important source of marine INPs, particularly during periods of enhanced biological productivity. Recent mesocosm experiments using natural seawater spiked with nutrients have revealed that marine INPs are derived from two separate classes of organic matter in SSAs. Despite this finding, existing parameterizations for marine INP abundance are based solely on single variables such as SSA organic carbon (OC) or SSA surface area, which may mask specific trends in the separate classes of INP. The goal of this paper is to improve the understanding of the connection between ocean biology and marine INP abundance by reporting results from a field study and proposing a new parameterization of marine INPs that accounts for the two associated classes of organic matter. The PEACETIME cruise took place from 10 May to 10 June 2017 in the Mediterranean Sea. Throughout the cruise, INP concentrations in the surface microlayer (INPSML) and in SSAs (INPSSA) produced using a plunging aquarium apparatus were continuously monitored while surface seawater (SSW) and SML biological properties were measured in parallel. The organic content of artificially generated SSAs was also evaluated. INPSML concentrations were found to be lower than those reported in the literature, presumably due to the oligotrophic nature of the Mediterranean Sea. A dust wet deposition event that occurred during the cruise increased the INP concentrations measured in the SML by an order of magnitude, in line with increases in iron in the SML and bacterial abundances. Increases in INPSSA were not observed until after a delay of 3 days compared to increases in the SML and are likely a result of a strong influence of bulk SSW INPs for the temperatures investigated (T=−18 ∘C for SSAs, T=−15 ∘C

Published
2021
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78. A two-component parameterization of marine ice-nucleating particles based on seawater biology and sea spray aerosol measurements in the mediterranean sea

Author

Centre National de la Recherche Scientifique (France), Institut national des sciences de l'Univers (France), Commissariat à l'Ènergie Atomique et aux Ènergies Alternatives (France), Institut Français de Recherche pour l'Exploitation de la Mer, Météo-France, European Commission, Ocean Biology and Biogeochemistry (US), Trueblood, Jonathan V., Nicosia, Alessia, Engel, Anja, Zäncker, Birthe, Rinaldi, Matteo, Freney, Evelyn, Thyssen, Melilotus, Obernosterer, Ingrid, Dinasquet, Julie, Belosi, Franco, Tovar-Sánchez, Antonio, Rodríguez-Romero, Araceli, Santachiara, Gianni, Guieu, Cécile, Sellegri, Karine, Centre National de la Recherche Scientifique (France), Institut national des sciences de l'Univers (France), Commissariat à l'Ènergie Atomique et aux Ènergies Alternatives (France), Institut Français de Recherche pour l'Exploitation de la Mer, Météo-France, European Commission, Ocean Biology and Biogeochemistry (US), Trueblood, Jonathan V., Nicosia, Alessia, Engel, Anja, Zäncker, Birthe, Rinaldi, Matteo, Freney, Evelyn, Thyssen, Melilotus, Obernosterer, Ingrid, Dinasquet, Julie, Belosi, Franco, Tovar-Sánchez, Antonio, Rodríguez-Romero, Araceli, Santachiara, Gianni, Guieu, Cécile, and Sellegri, Karine

Abstract

Ice-nucleating particles (INPs) have a large impact on the climate-relevant properties of clouds over the oceans. Studies have shown that sea spray aerosols (SSAs), produced upon bursting of bubbles at the ocean surface, can be an important source of marine INPs, particularly during periods of enhanced biological productivity. Recent mesocosm experiments using natural seawater spiked with nutrients have revealed that marine INPs are derived from two separate classes of organic matter in SSAs. Despite this finding, existing parameterizations for marine INP abundance are based solely on single variables such as SSA organic carbon (OC) or SSA surface area, which may mask specific trends in the separate classes of INP. The goal of this paper is to improve the understanding of the connection between ocean biology and marine INP abundance by reporting results from a field study and proposing a new parameterization of marine INPs that accounts for the two associated classes of organic matter. The PEACETIME cruise took place from 10 May to 10 June 2017 in the Mediterranean Sea. Throughout the cruise, INP concentrations in the surface microlayer r (INPSML) and in SSAs (INPSSA) produced using a plunging aquarium apparatus were continuously monitored while surface seawater (SSW) and SML biological properties were measured in parallel. The organic content of artificially generated SSAs was also evaluated. INPSML concentrations were found to be lower than those reported in the literature, presumably due to the oligotrophic nature of the Mediter ranean Sea. A dust wet deposition event that occurred during the cruise increased the INP concentrations measured in the SML by an order of magnitude, in line with increases in iron in the SML and bacterial abundances. Increases in INPSSA were not observed until after a delay of 3 days compared to increases in the SML and are likely a result of a strong in fluence of bulk SSW INPs for the temperatures investigated (T =-18 °C for SSAs, T =

Published
2021

79. Subsurface iron accumulation and rapid aluminum removal in the Mediterranean following African dust deposition

Author

European Commission, Centre National de la Recherche Scientifique (France), Institut national des sciences de l'Univers (France), Institut Français de Recherche pour l'Exploitation de la Mer, Commissariat à l'Ènergie Atomique et aux Ènergies Alternatives (France), Météo-France, Bressac, Matthieu, Wagener, Thibaut, Leblond, Nathalie, Tovar-Sánchez, Antonio, Ridame, Céline, Taillandier, Vincent, Albani, Samuel, Guasco, Sophie, Dufour, Aurélie, Jacquet, Stéphanie H. M., Dulac, François, Desboeufs, Karine, Guieu, Cécile, European Commission, Centre National de la Recherche Scientifique (France), Institut national des sciences de l'Univers (France), Institut Français de Recherche pour l'Exploitation de la Mer, Commissariat à l'Ènergie Atomique et aux Ènergies Alternatives (France), Météo-France, Bressac, Matthieu, Wagener, Thibaut, Leblond, Nathalie, Tovar-Sánchez, Antonio, Ridame, Céline, Taillandier, Vincent, Albani, Samuel, Guasco, Sophie, Dufour, Aurélie, Jacquet, Stéphanie H. M., Dulac, François, Desboeufs, Karine, and Guieu, Cécile

Abstract

Mineral dust deposition is an important supply mechanism for trace elements in the low-latitude ocean. Our understanding of the controls of such inputs has been mostly built on laboratory and surface ocean studies. The lack of direct observations and the tendency to focus on near-surface waters prevent a comprehensive evaluation of the role of dust in oceanic biogeochemical cycles. In the frame of the PEACETIME project (ProcEss studies at the Air-sEa Interface after dust deposition in the MEditerranean sea), the responses of the aluminum (Al) and iron (Fe) cycles to two dust wet deposition events over the central and western Mediterranean Sea were investigated at a timescale of hours to days using a comprehensive dataset gathering dissolved and suspended particulate concentrations, along with sinking fluxes. Dissolved Al (dAl) removal was dominant over dAl released from dust. The Fe/Al ratio of suspended and sinking particles revealed that biogenic particles, and in particular diatoms, were key in accumulating and exporting Al relative to Fe. By combining these observations with published Al/Si ratios of diatoms, we show that adsorption onto biogenic particles, rather than active uptake, represents the main sink for dAl in Mediterranean waters. In contrast, systematic dissolved Fe (dFe) accumulation occurred in subsurface waters (∼ 100-1000m), while dFe input from dust was only transient in the surface mixed layer. The rapid transfer of dust to depth, the Fe-binding ligand pool in excess to dFe in subsurface (while nearly saturated in surface), and low scavenging rates in this particle-poor depth horizon are all important drivers of this subsurface dFe enrichment. At the annual scale, this previously overlooked mechanism may represent an additional pathway of dFe supply for the surface ocean through diapycnal diffusion and vertical mixing. However, low subsurface dFe concentrations observed at the basin scale (<0.5nmolkg-1) cause us to question the residence time fo

Published
2021

81. Ocean–Atmosphere Interactions of Particles

Author

de Leeuw, Gerrit, primary, Guieu, Cécile, additional, Arneth, Almuth, additional, Bellouin, Nicolas, additional, Bopp, Laurent, additional, Boyd, Philip W., additional, van der Gon, Hugo A. C. Denier, additional, Desboeufs, Karine V., additional, Dulac, François, additional, Facchini, M. Cristina, additional, Gantt, Brett, additional, Langmann, Baerbel, additional, Mahowald, Natalie M., additional, Marañón, Emilio, additional, O’Dowd, Colin, additional, Olgun, Nazli, additional, Pulido-Villena, Elvira, additional, Rinaldi, Matteo, additional, Stephanou, Euripides G., additional, and Wagener, Thibaut, additional

Published
2013
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82. Supplementary material to "Phosphorus cycling in the upper waters of the Mediterranean Sea (Peacetime cruise): relative contribution of external and internal sources"

Author

Pulido-Villena, Elvira, primary, Desboeufs, Karine, additional, Djaoudi, Kahina, additional, Van Wambeke, France, additional, Barrillon, Stéphanie, additional, Doglioli, Andrea, additional, Petrenko, Anne, additional, Taillandier, Vincent, additional, Fu, Franck, additional, Gaillard, Tiphanie, additional, Guasco, Sophie, additional, Nunige, Sandra, additional, Triquet, Sylvain, additional, and Guieu, Cécile, additional

Published
2021
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83. Supplementary material to &quot;Subsurface iron accumulation and rapid aluminium removal in the Mediterranean following African dust deposition&quot;

Author

Bressac, Matthieu, primary, Wagener, Thibaut, additional, Leblond, Nathalie, additional, Tovar-Sánchez, Antonio, additional, Ridame, Céline, additional, Albani, Samuel, additional, Guasco, Sophie, additional, Dufour, Aurélie, additional, Jacquet, Stéphanie, additional, Dulac, François, additional, Desboeufs, Karine, additional, and Guieu, Cécile, additional

Published
2021
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84. Supplementary material to "Impact of dust addition on the metabolism of Mediterranean plankton communities and carbon export under present and future conditions of pH and temperature"

Author

Gazeau, Frédéric, primary, Van Wambeke, France, additional, Marañón, Emilio, additional, Pérez-Lorenzo, Maria, additional, Alliouane, Samir, additional, Stolpe, Christian, additional, Blasco, Thierry, additional, Leblond, Nathalie, additional, Zäncker, Birthe, additional, Engel, Anja, additional, Marie, Barbara, additional, Dinasquet, Julie, additional, and Guieu, Cécile, additional

Published
2021
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85. A two-component parameterization of marine ice-nucleating particles based on seawater biology and sea spray aerosol measurements in the Mediterranean Sea

Author

Trueblood, Jonathan V., primary, Nicosia, Alessia, additional, Engel, Anja, additional, Zäncker, Birthe, additional, Rinaldi, Matteo, additional, Freney, Evelyn, additional, Thyssen, Melilotus, additional, Obernosterer, Ingrid, additional, Dinasquet, Julie, additional, Belosi, Franco, additional, Tovar-Sánchez, Antonio, additional, Rodriguez-Romero, Araceli, additional, Santachiara, Gianni, additional, Guieu, Cécile, additional, and Sellegri, Karine, additional

Published
2021
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89. Introduction: Process studies at the air–sea interface after atmospheric deposition in the Mediterranean Sea – objectives and strategy of the PEACETIME oceanographic campaign (May–June 2017)

Author

Guieu, Cécile, primary, D'Ortenzio, Fabrizio, additional, Dulac, François, additional, Taillandier, Vincent, additional, Doglioli, Andrea, additional, Petrenko, Anne, additional, Barrillon, Stéphanie, additional, Mallet, Marc, additional, Nabat, Pierre, additional, and Desboeufs, Karine, additional

Published
2020
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90. Impact of dust enrichment on Mediterranean plankton communities under present and future conditions of pH and temperature: an experimental overview

Author

Gazeau, Frédéric, primary, Ridame, Céline, additional, Van Wambeke, France, additional, Alliouane, Samir, additional, Stolpe, Christian, additional, Irisson, Jean-Olivier, additional, Marro, Sophie, additional, Grisoni, Jean-Michel, additional, De Liège, Guillaume, additional, Nunige, Sandra, additional, Djaoudi, Kahina, additional, Pulido-Villena, Elvira, additional, Dinasquet, Julie, additional, Obernosterer, Ingrid, additional, Catala, Philippe, additional, and Guieu, Cécile, additional

Published
2020
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92. Supplementary material to &quot;Contrasted release of insoluble elements (Fe, Al, REE, Th, Pa) after dust deposition in seawater: a tank experiment approach&quot;

Author

Roy-Barman, Matthieu, primary, Folio, Lorna, additional, Douville, Eric, additional, Leblond, Nathalie, additional, Gazeau, Fréderic, additional, Bressac, Matthieu, additional, Wagener, Thibaut, additional, Ridame, Céline, additional, Desboeufs, Karine, additional, and Guieu, Cécile, additional

Published
2020
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93. Supplementary material to &quot;A Two-Component Parameterization of Marine Ice Nucleating Particles Based on Seawater Biology and Sea Spray Aerosol Measurements in the Mediterranean Sea&quot;

Author

Trueblood, Jonathan V., primary, Nicosia, Alesia, additional, Engel, Anja, additional, Zäncker, Birthe, additional, Rinaldi, Matteo, additional, Freney, Evelyn, additional, Thyssen, Melilotus, additional, Obernosterer, Ingrid, additional, Dinasquet, Julie, additional, Belosi, Franco, additional, Tovar-Sánchez, Antonio, additional, Rodriguez-Romero, Araceli, additional, Santachiara, Gianni, additional, Guieu, Cécile, additional, and Sellegri, Karine, additional

Published
2020
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94. Supplementary material to "Mediterranean nascent sea spray organic aerosol and relationships with seawater biogeochemistry"

Author

Freney, Evelyn, primary, Sellegri, Karine, additional, Nicosia, Alessia, additional, Trueblood, Jonathan T., additional, Rinaldi, Matteo, additional, Williams, Leah R., additional, Prévôt, André S. H., additional, Thyssen, Melilotus, additional, Grégori, Gérald, additional, Haëntjens, Nils, additional, Dinasquet, Julie, additional, Obernosterer, Ingrid, additional, Van-Wambeke, France, additional, Engel, Anja, additional, Zäncker, Birthe, additional, Desboeufs, Karine, additional, Asmi, Eija, additional, Timmonen, Hilka, additional, and Guieu, Cécile, additional

Published
2020
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95. A Two-Component Parameterization of Marine Ice Nucleating Particles Based on Seawater Biology and Sea Spray Aerosol Measurements in the Mediterranean Sea

Author

Trueblood, Jonathan V., primary, Nicosia, Alesia, additional, Engel, Anja, additional, Zäncker, Birthe, additional, Rinaldi, Matteo, additional, Freney, Evelyn, additional, Thyssen, Melilotus, additional, Obernosterer, Ingrid, additional, Dinasquet, Julie, additional, Belosi, Franco, additional, Tovar-Sánchez, Antonio, additional, Rodriguez-Romero, Araceli, additional, Santachiara, Gianni, additional, Guieu, Cécile, additional, and Sellegri, Karine, additional

Published
2020
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96. Mediterranean nascent sea spray organic aerosol and relationships with seawater biogeochemistry

Author

Freney, Evelyn, primary, Sellegri, Karine, additional, Nicosia, Alessia, additional, Trueblood, Jonathan T., additional, Rinaldi, Matteo, additional, Williams, Leah R., additional, Prévôt, André S. H., additional, Thyssen, Melilotus, additional, Grégori, Gérald, additional, Haëntjens, Nils, additional, Dinasquet, Julie, additional, Obernosterer, Ingrid, additional, Van-Wambeke, France, additional, Engel, Anja, additional, Zäncker, Birthe, additional, Desboeufs, Karine, additional, Asmi, Eija, additional, Timmonen, Hilka, additional, and Guieu, Cécile, additional

Published
2020
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97. Characterizing the surface microlayer in the Mediterranean Sea: trace metal concentrations and microbial plankton abundance

Author

Tovar-Sánchez, Antonio, primary, Rodríguez-Romero, Araceli, additional, Engel, Anja, additional, Zäncker, Birthe, additional, Fu, Franck, additional, Marañón, Emilio, additional, Pérez-Lorenzo, María, additional, Bressac, Matthieu, additional, Wagener, Thibaut, additional, Triquet, Sylvain, additional, Siour, Guillaume, additional, Desboeufs, Karine, additional, and Guieu, Cécile, additional

Published
2020
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99. Process studies at the air-sea interface after atmospheric deposition in the Mediterranean Sea: objectives and strategy of the PEACETIME oceanographic campaign (May–June 2017)

Author

Guieu, Cécile, primary, D'Ortenzio, Fabrizio, additional, Dulac, François, additional, Taillandier, Vincent, additional, Doglioli, Andrea, additional, Petrenko, Anne, additional, Barrillon, Stéphanie, additional, Mallet, Marc, additional, Nabat, Pierre, additional, and Desboeufs, Karine, additional

Published
2020
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100. Who is the boss? Employment/work relationship and the ambivalence of private firms in urban bus networks

Author

Méhaut, Philippe, Chanut-Guieu, Cécile, Kornig, Cathel, Louit-Martinod, Nathalie, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Chanut-Guieu, Cécile, and Laboratoire d'Economie et de Sociologie du Travail (LEST)

Subjects
[SHS.GESTION]Humanities and Social Sciences/Business administration, [SHS.GESTION] Humanities and Social Sciences/Business administration, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018

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