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101. Start-up tribu : comment entreprendre avec sa communauté.

Author: CHANUT-GUIEU, Cécile
Published: 2022
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102. Lithogenic carbon pump': toward a quantification to its contribution to POC export in the ocean

Author: Guieu, Cécile, Aumont, Olivier, Gazeau, Frédéric, Louis, Justine, Bressac, Matthieu, 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), 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), IUT de Saint-Brieuc, and Université de Rennes (UR)
Subjects: [SDE]Environmental Sciences
Published: 2019

103. Supporting datasets used in in the Geophysical Research Letters paper entitled 'Major impact of dust deposition on the productivity of the Arabian Sea'

Author: Guieu, Cécile, Muchamad Al Azhar, Aumont, Olivier, Mahowald, Natalie, Levy, Marina, Ethé, Christian, and Lachkar, Zouhair
Abstract: This archive contains netCDF files corresponding to datasets used in the Geophysical Research Letters paper entitled "Major impact of dust deposition on the productivity of the Arabian Sea" by Cécile Guieu, Muchamad Al Azhar, Olivier Aumont, Natalie Mahowald, Marina Levy, Christian Ethé, Zouhair Lachkar Archives are presented for 'all deposition', 'no deposition' and 'all-except-iron deposition' simulations described in the main manuscript. The data is in standard netCDF file format, which is readily readable using standard netCDF tools. Variables names/content/dimensions and units are described in the netcdfs metadata. Below is a brief description of the available files and their content (the detail of the simulations is provided in the paper). 1) All deposition run: roms_avg_AS_alldep_monthly_clim.nc ===> monthly climatology of simulated state variables in the 'all deposition' run roms_diabio_avg_AS_alldep_monthly_clim.nc ===> monthly climatology of simulated biological fluxes in the 'all deposition' run 1) No deposition run: roms_avg_AS_nodep_monthly_clim.nc ===> monthly climatology of simulated state variables in the 'No deposition' run roms_diabio_avg_AS_nodep_monthly_clim.nc ===> monthly climatology of simulated biological fluxes in the 'No deposition' run 1) All-except-iron deposition run: roms_avg_AS_noFedep_monthly_clim.nc ===> monthly climatology of simulated state variables in the 'all-except-iron deposition' run roms_diabio_avg_AS_noFedep_monthly_clim.nc ===> monthly climatology of simulated biological fluxes in the 'all-except-iron deposition' run 4) Grid files (contain the details of the ROMS grids such as the latitude, longitude and depth information of grid cells): roms_grd.nc ===> Roms grid file for all simulations
Published: 2019
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104. Characterizing the surface microlayer in the Mediterranean Sea: trace metal concentrations and microbial plankton abundance

Author: Tovar-sanchez, Antonio, Rodriguez-romero, Araceli, Engel, Anja, Zancker, Birthe, Fu, Franck, Maranon, Emilio, Perez-lorenzo, Maria, Bressac, Matthieu, Wagener, Thibault, Desboeufs, Karine, Triquet, Sylvain, Siour, Guillaume, Guieu, Cécile, Tovar-sanchez, Antonio, Rodriguez-romero, Araceli, Engel, Anja, Zancker, Birthe, Fu, Franck, Maranon, Emilio, Perez-lorenzo, Maria, Bressac, Matthieu, Wagener, Thibault, Desboeufs, Karine, Triquet, Sylvain, Siour, Guillaume, and Guieu, Cécile
Abstract: The Sea Surface Microlayer (SML) is known to be enriched in trace metals relative to the underlaying water and to harbor diverse microbial communities (i.e. neuston). However, the processes linking metals and biota in the SML are not yet fully understood. In this study, we analyzed the metal (Cd, Co, Cu, Fe, Ni, Mo, V, Zn and Pb) concentrations in aerosol samples, SML (dissolved and total fractions) and in subsurface waters (SSW; dissolved fraction at ~ 1 m depth) from the Western Mediterranean Sea during a cruise in May–June 2017. The bacterial community composition and abundance in the SML and SSW, and the primary production and Chl-a in the SSW were measured simultaneously at all stations during the cruise. Residence times of particulate metals derived from aerosols deposition ranged from a couple of minutes for Co (2.7 ± 0.9 min; more affected by wind conditions) to a few hours for Cu (3.0 ± 1.9 h). Concentration of most dissolved metals in both, the SML and SSW, were well correlated with the salinity gradient and showed the characteristic eastward increase in surface waters of the Mediterranean Sea (MS). Contrarily, the total fraction of some reactive metals in the SML (i.e. Cu, Fe, Pb and Zn) showed negative trends with salinity, these trends of concentrations seem to be associate to microbial uptake. Our results suggest a toxic effect of Ni on neuston and microbiology community’s abundance of the top meter of the surface waters of the Western Mediterranean Sea.
Published: 2020
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105. 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, D'Ortenzio, Fabrizio, Dulac, François, Taillandier, Vincent, Doglioli, Andrea, Petrenko, Anne, Barrillon, Stéphanie, Mallet, Marc, Nabat, Pierre, Desboeufs, Karine, Guieu, Cécile, D'Ortenzio, Fabrizio, Dulac, François, Taillandier, Vincent, Doglioli, Andrea, Petrenko, Anne, Barrillon, Stéphanie, Mallet, Marc, Nabat, Pierre, and Desboeufs, Karine
Abstract: In spring, the Mediterranean Sea, a well-stratified low nutrient low chlorophyll region, receives atmospheric deposition both desert dust from the Sahara and airborne particles from anthropogenic sources. Such deposition translates into a supply of new nutrients and trace metals for the surface waters that likely impact biogeochemical cycles. However, the quantification of the impacts and the processes involved are still far from being assessed in situ. In this paper, we provide a state of the art regarding dust deposition and its impact on the Mediterranean Sea biogeochemistry and we describe in this context the objectives and strategy of the PEACETIME project and cruise, entirely dedicated to filling this knowledge gap. Our strategy to go a step forward than in previous approaches in understanding these impacts by catching a real deposition event at sea is detailed. The PEACETIME oceanographic campaign took place in May–June 2017 and we describe how we were able to successfully adapt the planned transect in order to sample a Saharan dust deposition event, thanks to a dedicated strategy, so-called Fast Action. That was successful, providing, for the first time in our knowledge, a coupled atmospheric and oceanographic sampling before, during and after an atmospheric deposition event. Atmospheric and marine in situ observations and process studies have been conducted in contrasted area and we summarize the work performed at sea, the type of data acquired and their valorization in the papers published in the special issue.
Published: 2020
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106. 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: 2020
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107. 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, Roy-barman, Matthieu, Foliot, Lorna, Douville, Eric, Leblond, Nathalie, Gazeau, Frédéric, Bressac, Matthieu, Wagener, Thibaut, Ridame, Céline, Desboeufs, Karine, and Guieu, Cécile
Abstract: The release of lithogenic elements (which are often assumed to be insoluble) such as Aluminum (Al), Iron (Fe), Rare Earth Elements (REE), Thorium (Th) and Protactinium (Pa) by Saharan dust reaching Mediterranean seawater was studied through tank experiments over 3 to 4 days under controlled conditions including control without dust addition and dust seeding under present and future climate conditions (+3 °C and −0.3 pH unit). Unfiltered surface seawater from 3 oligotrophic regions (Tyrrhenian Sea, Ionian Sea and Algerian Basin) were used. The maximum dissolution fractions were low for all seeding experiments: less than 0.3 % for Fe, 1 % for 232Th and Al, about 2–5 % for REE 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 REE were scavenged back on the 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 thorium and REE in seawater, leading to a lower Th release and a higher light REE release under increased greenhouse conditions.
Published: 2020
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108. Contribution of electroactive humic substances to the iron-binding ligands released during microbial remineralisation of sinking particles

Author: Whitby, Hannah, Bressac, Matthieu, Sarthou, Geraldine, Ellwood, Michael J., Guieu, Cécile, Boyd, Philip W., Whitby, Hannah, Bressac, Matthieu, Sarthou, Geraldine, Ellwood, Michael J., Guieu, Cécile, and Boyd, Philip W.
Abstract: Iron is a key micronutrient in seawater, but concentrations would be negligible without the presence of organic ligands. The processes influencing the ligand pool composition are poorly constrained, limiting our understanding of the controls on dissolved iron distributions. To address this, the release of iron and iron‐binding ligands during the microbial remineralisation of sinking particles was investigated by deploying in situ particle interceptor/incubator devices at subsurface sites in the Mediterranean Sea and Subantarctic. Analyses revealed the pool of released ligands was largely dominated by electroactive humic substances (74 ± 28%). The release of ligands during remineralisation ensured that concurrently released iron remained in solution, which is crucial for iron regeneration. This study presents compelling evidence of the key role of humic ligands in the subsurface replenishment of dissolved iron and thus on the wider oceanic dissolved iron inventory, which ultimately controls the magnitude of iron resupplied to the euphotic zone. Plain language summary Microscopic plants and animals in seawater require nutrients to survive. One of these key nutrients is iron, dissolved in seawater at very low concentrations. The growth of around half of the microscopic life in the upper ocean is dependent on the availability of this dissolved iron. These organisms form the bottom of the food chain, and their growth is linked to marine productivity and the drawdown of carbon into the deep ocean, in turn influencing climate change. Because iron tends to not dissolve easily in seawater, it must bind with compounds known as ligands, which help keep iron dissolved. However, processes controlling the composition of this ligand pool are poorly understood. As material sinks through the water column, it is broken down by marine microbes, releasing iron and ligands. Here we have studied the release of iron, ligands and a specific type of ligand known as humic substances, during
Published: 2020
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109. Biochemical dataset collected during the Peacetime cruise

Author: Schmechtig, Catherine [schmechtig@obs-vlfr.fr], Guieu, Cécile, Desboeufs, Karine, Albani, Samuel, Alliouane, Samir, Aumont, Olivier, Barbieux, Marie, Barrillon, Stéphanie, Baudoux, Anne Claire, Berline, Léo, Bhairy, Nahib, Bigeard, Estelle, Bloss, Matthew, Bressac, Matthieu, Brito, J., Carlotti, François, Liege, Guillaume de, Dinasquet, Julie, Djaoudi, Kahina, Doglioli, Andrea M., D'Ortenzio, Fabrizio, Doussin, Jean François, Duforet, Lucile, Dulac, François, Dutay, Jean Claude, Engel, Anja, Feliú-Brito, Guillermo, Ferre, Hélène, Formenti, Paula, Fu, Franck, García, David, Garel, Marc, Gazeau, Frédéric, Giorio, Chiara, Gregori, Gérald, Grisoni, Jean Michel, Guasco, Sophie, Guittonneau, Joris, Haëntjens, Nils, Heimburger, Lars Eric, Helias, Sandra, Jacquet, Stéphanie H. M., Laurent, Brice, Leblond, Nathalie, Lefevre, Dominique, Mallet, Marc, Marañón, Emilio, Nabat, Pierre, Nicosia, Alessia, Obernosterer, Ingrid, Pérez-Lorenzo, María, Petrenko, Anne, Pulido-Villena, Elvira, Raimbault, Patrick, Ridame, Céline, Riffault, Véronique, Rougier, Gilles, Rousselet, Louise, Roy-Barman, Matthieu, Saiz-Lopez, A., Schmechtig, Catherine, Sellegri, Karine, Siour, Guillaume, Taillandier, Vincent, Tamburini, Christian, Thyssen, Melilotus, Tovar-Sánchez, Antonio, Triquet, Sylvain, Uitz, Julia, Wambeke, France van, Wagener, Thibaut, Zaencker, Birthe, Schmechtig, Catherine [schmechtig@obs-vlfr.fr], Guieu, Cécile, Desboeufs, Karine, Albani, Samuel, Alliouane, Samir, Aumont, Olivier, Barbieux, Marie, Barrillon, Stéphanie, Baudoux, Anne Claire, Berline, Léo, Bhairy, Nahib, Bigeard, Estelle, Bloss, Matthew, Bressac, Matthieu, Brito, J., Carlotti, François, Liege, Guillaume de, Dinasquet, Julie, Djaoudi, Kahina, Doglioli, Andrea M., D'Ortenzio, Fabrizio, Doussin, Jean François, Duforet, Lucile, Dulac, François, Dutay, Jean Claude, Engel, Anja, Feliú-Brito, Guillermo, Ferre, Hélène, Formenti, Paula, Fu, Franck, García, David, Garel, Marc, Gazeau, Frédéric, Giorio, Chiara, Gregori, Gérald, Grisoni, Jean Michel, Guasco, Sophie, Guittonneau, Joris, Haëntjens, Nils, Heimburger, Lars Eric, Helias, Sandra, Jacquet, Stéphanie H. M., Laurent, Brice, Leblond, Nathalie, Lefevre, Dominique, Mallet, Marc, Marañón, Emilio, Nabat, Pierre, Nicosia, Alessia, Obernosterer, Ingrid, Pérez-Lorenzo, María, Petrenko, Anne, Pulido-Villena, Elvira, Raimbault, Patrick, Ridame, Céline, Riffault, Véronique, Rougier, Gilles, Rousselet, Louise, Roy-Barman, Matthieu, Saiz-Lopez, A., Schmechtig, Catherine, Sellegri, Karine, Siour, Guillaume, Taillandier, Vincent, Tamburini, Christian, Thyssen, Melilotus, Tovar-Sánchez, Antonio, Triquet, Sylvain, Uitz, Julia, Wambeke, France van, Wagener, Thibaut, and Zaencker, Birthe
Abstract: The general objective of the PEACETIME cruise is to study the fundamental processes and their interactions at the ocean-atmosphere interface, occurring after atmospheric deposition (especially Saharan dust) in the Mediterranean Sea, and how these processes impact the functioning of the pelagic ecosystem. During the proposed 33 days cruise in the western and central Mediterranean Sea in May 2017, we will study the impact of atmospheric deposition on the cycles of chemical elements, on marine biogeochemical processes and fluxes, on marine aerosols emission and how ongoing changes will impact the functioning of Mediterranean Sea communities in the future. The cruise is designed to explore a variety of oligotrophic regimes. Combining in situ observations both in the atmosphere and the ocean, and in situ and minicosm-based on-board process studies, the 40 embarking scientists from atmosphere and ocean sciences will characterize the chemical, biological and physical/optical properties of both the atmosphere and the sea-surface microlayer, mixed layer and deeper waters. The PEACETIME strategy (season and cruise track) associated to a combination of dust transport forecasting tools and near real-time satellite remote sensing is designed to maximize the probability to catch a Saharan dust deposition event in a stratified water column in order to follow the associated processes in-situ. This coordinated multidisciplinary effort will allow us to fill the current weaknesses/lacks in our knowledge of atmospheric deposition impact in the ocean and feedbacks to the atmosphere in such oligotrophic systems. As a key joint-project between MERMEX and CHARMEX : The PEACETIME project comes in the scope of the regional multidisciplinaryprogramme MISTRALS (Mediterranean Integrated STudies at Regional And Local Scales ), which aims at predicting the evolution of this region following strong expected changes in climate and human pressures. In this framework, the PEACETIME project constitute
Published: 2020

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

Author: Ministerio de Ciencia, Innovación y Universidades (España), Tovar-Sánchez, Antonio, Rodríguez-Romero, Araceli, Engel, Anja, Zäncker, Birthe, Fu, Franck, Marañón, Emilio, Pérez-Lorenzo, María, Bressac, Matthieu, Wagener, Thibaut, Triquet, Sylvain, Siour, Guillaume, Desboeufs, Karine, Guieu, Cécile, Ministerio de Ciencia, Innovación y Universidades (España), Tovar-Sánchez, Antonio, Rodríguez-Romero, Araceli, Engel, Anja, Zäncker, Birthe, Fu, Franck, Marañón, Emilio, Pérez-Lorenzo, María, Bressac, Matthieu, Wagener, Thibaut, Triquet, Sylvain, Siour, Guillaume, Desboeufs, Karine, and Guieu, Cécile
Abstract: The Sea Surface Microlayer (SML) is known to be enriched by trace metals relative to the underlying water and harbor diverse microbial communities (i.e., neuston). However, the processes linking metals and biota in the SML are not yet fully understood. The metal (Cd, Co, Cu, Fe, Ni, Mo, V, Zn and Pb) concentrations in aerosol samples in the SML (dissolved and total fractions) and in subsurface waters (SSWs; dissolved fraction at ∼1 m depth) from the western Mediterranean Sea were analyzed in this study during a cruise in May–June 2017. The composition and abundance of the bacterial community in the SML and SSW, the primary production, and Chl a in the SSW were measured simultaneously at all stations during the cruise. Residence times in the SML of metals derived from aerosol depositions were highly variable and ranged from minutes for Fe (3.6±6.0 min) to a few hours for Cu (5.8±6.2 h). Concentrations of most of the dissolved metals in both the SML and SSW were positively correlated with the salinity gradient and showed the characteristic eastward increase in the surface waters of the Mediterranean Sea (MS). In contrast, the total fraction of some reactive metals in the SML (i.e., Cu, Fe, Pb and Zn) showed a negative correlation with salinity and a positive correlation with microbial abundance, which might be associated with microbial uptake. Our results show a strong negative correlation between the dissolved and total Ni concentration and heterotrophic bacterial abundance in the SML and SSW, but we cannot ascertain whether this correlation reflects a toxicity effect or is the result of some other process.
Published: 2020

111. Release of cadmium in the Danube estuary: contribution of physical and chemical processes as determined by an experimental approach

Author: Garnier, Jean-Marie and Guieu, Cécile
Published: 2003
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112. 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, Frederic, Tovar-Sanchez, Antonio, Baudoux, Anne-Claire, and Guieu, Cécile
Subjects: NITROGEN fixation, DUST, CARBON fixation, HIGH density polyethylene, MINERAL dusts, DETECTION limit, NUCLEOTIDE sequencing
Abstract: N2 fixation rates were measured in the 0-1000 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 of N2 fixation was not related to Fe, P nor N stocks, the surface composition of the diazotrophic community indicated a strong eastward increasing longitudinal gradient for the relative abundance of non-cyanobacterial diazotrophs (NCD) (mainly γ-Proteobacteria) and conversely eastward decreasing for UCYN-A (mainly -A1 and -A3) as did N2 fixation rates. UCYN-A4 and -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 72.1 nmol N L-1 d-1, which could support up to 19 % of primary production. At this station at 1%PAR depth, UCYN-A4 represented up to 94 % of the diazotrophic community. These in situ observations of higher UCYN-A relative abundance in nutrient rich stations while NCD increased in the more oligotrophic stations, suggest that the nutrient conditions could determine the composition of the diazotrophic communities and in turn the 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 (3-4 days) experiments at three stations. New nutrients from simulated dust deposition triggered a significant stimulation of N2 fixation (from 41 % to 565 %). The strongest increase in N2 fixation was observed at the stations dominated by NCD and did not lead on this short time scale to change in the diazotrophic community composition. Under projected future conditions, N2 fixation was either exacerbated 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 NCD (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. [ABSTRACT FROM AUTHOR]
Published: 2021
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113. Conseils d’administration dans les PME et les entreprises familiales. Un réexamen de la thématique 18 ans après l’article séminal de Morten Huse (ERD 2000)

Author: Chanut-Guieu, Cécile, Guieu, Gilles, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur le Transport et la Logistique (CRET-LOG), Aix Marseille Université (AMU), Laboratoire d'Economie et de Sociologie du Travail (LEST), and Guieu, Gilles
Subjects: [SHS.GESTION]Humanities and Social Sciences/Business administration, [SHS.GESTION] Humanities and Social Sciences/Business administration, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2018

114. In-depth characterization of diazotroph activity across the western tropical South Pacific hotspot of N2 fixation (OUTPACE cruise)

Author: Bonnet, Sophie, Caffin, Mathieu, Berthelot, Hugo, Grosso, Olivier, Benavides, Mar, Helias-Nunige, Sandra, Guieu, Cécile, Stenegren, Marcus, and Foster, Rachel Ann
Abstract: Here we report N2 fixation rates from a ∼ 4000 km transect in the western and central tropical South Pacific, a particularly undersampled region in the world ocean. Water samples were collected in the euphotic layer along a west to east transect from 160∘ E to 160∘ W that covered contrasting trophic regimes, from oligotrophy in the Melanesian archipelago (MA) waters to ultra-oligotrophy in the South Pacific Gyre (GY) waters. N2 fixation was detected at all 17 sampled stations with an average depth-integrated rate of 631 ± 286 µmolNm-2d-1 (range 196–1153 µmolNm-2d-1) in MA waters and of 85 ± 79 µmolNm-2d-1 (range 18–172 µmolNm-2d-1) in GY waters. Two cyanobacteria, the larger colonial filamentous Trichodesmium and the smaller UCYN-B, dominated the enumerated diazotroph community (> 80 %) and gene expression of the nifH gene (cDNA > 105 nifH copies L−1) in MA waters. Single-cell isotopic analyses performed by nanoscale secondary ion mass spectrometry (nanoSIMS) at selected stations revealed that Trichodesmium was always the major contributor to N2 fixation in MA waters, accounting for 47.1–83.8 % of bulk N2 fixation. The most plausible environmental factors explaining such exceptionally high rates of N2 fixation in MA waters are discussed in detail, emphasizing the role of macro- and micro-nutrient (e.g., iron) availability, seawater temperature and currents.
Published: 2018
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115. Vers un modèle intégré de la PME en hypercroissance. La place centrale de l'entrepreneur visionnaire

Author: Chanut-Guieu, Cécile, Guieu, Gilles, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur le Transport et la Logistique (CRET-LOG), Aix Marseille Université (AMU), Guieu, Gilles, 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

116. La création d’une dynamique durable d’hypercroissance

Author: Chanut-Guieu, Cécile, Guieu, Gilles, Tannery, Franck, Dana, Léo-Paul, Laboratoire d'Economie et de Sociologie du Travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur le Transport et la Logistique (CRET-LOG), Aix Marseille Université (AMU), COnception de l'ACTIon en Situation (COACTIS), Université Lumière - Lyon 2 (UL2)-Université Jean Monnet - Saint-Étienne (UJM), Montpellier Research in Management (MRM), Université Paul-Valéry - Montpellier 3 (UPVM)-Université de Perpignan Via Domitia (UPVD)-Groupe Sup de Co Montpellier (GSCM) - Montpellier Business School-Université de Montpellier (UM), Laboratoire d'économie et de sociologie du travail (LEST), COACTIS (COACTIS), Université Lumière - Lyon 2 (UL2)-Université Jean Monnet [Saint-Étienne] (UJM), and Université Montpellier 1 (UM1)-Université Paul-Valéry - Montpellier 3 (UPVM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Perpignan Via Domitia (UPVD)-Groupe Sup de Co Montpellier (GSCM) - Montpellier Business School-Université de Montpellier (UM)
Subjects: Medium-size firm, dominant logic, paradox, growth, ETI, [SHS.GESTION]Humanities and Social Sciences/Business administration, logique dominante, croissance, paradoxe, [SHS]Humanities and Social Sciences
Abstract: International audience; When the firm is undergoing hyper-growth (doubling its size in four years), this exacerbated development is characterized by numerous tensions. The notion of paradox allows for a positive understanding of the tensions of the growing company. How can a firm continue to grow and to renew itself without losing its balance? Through the longitudinal and multi-method analysis of the make-up of a medium-sized firm, we identify several dynamics that generate hyper-growth: (i) sustaining the pace of growth; (ii) extending strategic space; (iii) configurating the organization's SBUs; and (iv) transforming the strategic thought of the leader. These four represent the same dual structure: the dominant logic stabilizes and balances the action, whereas paradoxical tensions de-stabilize and question the action.; Le développement exacerbé de l’entreprise en hypercroissance est caractérisé par de nombreuses tensions. Comment l’entreprise continue-t-elle à croître et se renouveler sans perdre ses équilibres ? L’analyse longitudinale de la constitution d’une ETI nous permet d’identifier plusieurs dynamiques de construction de l’hypercroissance. Ces dynamiques relatives au rythme de croissance, à l’espace stratégique, aux activités et à la pensée du dirigeant présentent la même structure : la logique dominante équilibre l’action, alors que les tensions paradoxales la questionnent.
Published: 2018
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117. Characterising the surface microlayer in the Mediterranean Sea: trace metals concentration 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, Desboeuf, Karine, additional, Triquet, Sylvain, additional, Siour, Guillaume, additional, and Guieu, Cécile, additional
Published: 2019
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118. Supplementary material to "Characterising the surface microlayer in the Mediterranean Sea: trace metals concentration 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, Desboeuf, Karine, additional, Triquet, Sylvain, additional, Siour, Guillaume, additional, and Guieu, Cécile, additional
Published: 2019
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119. Major Impact of Dust Deposition on the Productivity of the Arabian Sea

Author: Guieu, Cécile, primary, Al Azhar, Muchamad, additional, Aumont, Olivier, additional, Mahowald, Natalie, additional, Levy, Marina, additional, Ethé, Christian, additional, and Lachkar, Zouhair, additional
Published: 2019
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120. Diversité des opérateurs et gouvernance locale dela petite enfance :quels enjeux pour le développement desterritoires, les modes d’organisation des acteurset la régulation de la qualité ?

Author: Chanut-Guieu, Cécile, Lhuillier, Vincent, Petrella, Francesca, Richez-Battesti, Nadine, 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: 2016

121. La professionnalisation des bénévoles

Author: Chanut-Guieu, Cécile, 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: Volunteers, Bénévolat, [SHS] Humanities and Social Sciences, Associations, Professionnalization, Professionnalisation, [SHS]Humanities and Social Sciences
Abstract: National audience; Les associations françaises, protégées et portées par la loi de 1901, doivent composer avec la professionnalisation de leurs bénévoles. - La professionnalisation croissante des bénévoles- Les avantages de la professionnalisation des bénévoles sont nombreux... - ... mais masquent des limites à ne pas négliger
Published: 2016

122. A Reassessment of Trace Metal Budgets in the Western Mediterranean Sea

Author: Elbaz-Poulichet, Françoise, Guieu, Cécile, and Morley, Nicholas H
Published: 2001
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123. Trichodesmium physiological ecology and phosphate reduction in the western tropical South Pacific

Author: Frischkorn, Kyle R., Krupke, Andreas, Guieu, Cécile, Louis, Justine, Rouco, Mónica, Salazar Estrada, Andrés E., Van Mooy, Benjamin A.S., Dyhrman, Sonya T., Lamont-Doherty Earth Observatory (LDEO), Columbia University [New York], Woods Hole Oceanographic Institution (WHOI), 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), and Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [SDV.MP.BAC]Life Sciences [q-bio]/Microbiology and Parasitology/Bacteriology, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: N2 fixation by the genus Trichodesmium is predicted to support a large proportion of the primary productivity across the oligotrophic oceans, regions that are considered among the largest biomes on Earth. Many of these environments remain poorly sampled, limiting our understanding of Trichodesmium physiological ecology in these critical oligotrophic regions. Trichodesmium colonies, communities that consist of the Trichodesmium host and their associated microbiome, were collected across the oligotrophic western tropical South Pacific (WTSP). These samples were used to assess host clade distribution, host and microbiome metabolic potential, and functional gene expression, with a focus on identifying Trichodesmium physiological ecology in this region. Genes sets related to phosphorus, iron, and phosphorus–iron co-limitation were dynamically expressed across the WTSP transect, suggestive of the importance of these resources in driving Trichodesmium physiological ecology in this region. A gene cassette for phosphonate biosynthesis was detected in Trichodesmium, the expression of which co-varied with the abundance of Trichodesmium Clade III, which was unusually abundant relative to Clade I in this environment. Coincident with the expression of the gene cassette, phosphate reduction to phosphite and low-molecular-weight phosphonate compounds was measured in Trichodesmium colonies. The expression of genes that enable use of such reduced-phosphorus compounds were also measured in both Trichodesmium and the microbiome. Overall, these results highlight physiological strategies employed by consortia in an undersampled region of the oligotrophic WTSP and reveal the molecular mechanisms underlying previously observed high rates of phosphorus reduction in Trichodesmium colonies.
Published: 2018
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124. N2 fixation as a dominant new N source in the western tropical South Pacific Ocean (OUTPACE cruise)

Author: CAFFIN , Mathieu, Moutin , Thierry, Foster , Rachel Ann, Bouruet-Aubertot , Pascale, Doglioli , Andrea Michelangelo, BERTHELOT , Hugo, Guieu , Cécile, Grosso , Olivier, Helias-Nunige , Sandra, Leblond , Nathalie, GIMENEZ , Audrey, Petrenko , Anne Alexandra, DE VERNEIL , Alain, Bonnet , Sophie, 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 ), Interactions et Processus au sein de la couche de Surface Océanique ( IPSO ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques ( LOCEAN ), Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ) -Muséum National d'Histoire Naturelle ( MNHN ) -Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), Processus et interactions de fine échelle océanique ( PROTEO ), Laboratoire d'océanographie de Villefranche ( LOV ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Institut national des sciences de l'Univers ( INSU - CNRS ) -Centre National de la Recherche Scientifique ( CNRS ), LEFE-CyBER programme, GOPS programme, CNES (BC T23, ZBC 4500048836), ANR-14-CE01-0007,OUTPACE,Sequestration océanique du CO2 et fixation d’azote atmosphérique dans l'océan oligotrophe (campagne océanographique OUTPACE). ( 2014 ), 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), Stockholm University, Interactions et Processus au sein de la couche de Surface Océanique (IPSO), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Processus et interactions de fine échelle océanique (PROTEO), 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)-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), 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), 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), ANR-14-CE01-0007,OUTPACE,Sequestration océanique du CO2 et fixation d'azote atmosphérique dans l'océan oligotrophe (campagne océanographique OUTPACE).(2014), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-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)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), 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)-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), 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: [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [ SDU.OCEAN ] Sciences of the Universe [physics]/Ocean, Atmosphere, ACL, DIAZOTROPH-DERIVED NITROGEN, MEDITERRANEAN-SEA, DIEL MIGRANT ZOOPLANKTON, STATION ALOHA, VERTICAL FLUX, CROCOSPHAERA-WATSONII, DINITROGEN-FIXATION, DISSOLVED ORGANIC-CARBON, [SDE.BE]Environmental Sciences/Biodiversity and Ecology, NORTH-ATLANTIC OCEAN, EXPERIMENT NEW-CALEDONIA
Abstract: We performed nitrogen (N) budgets in the photic layer of three contrasting stations representing different trophic conditions in the western tropical South Pacific (WTSP) Ocean during austral summer conditions (February–March 2015). Using a Lagrangian strategy, we sampled the same water mass for the entire duration of each long-duration (5 days) station, allowing us to consider only vertical exchanges for the budgets. We quantified all major vertical N fluxes both entering (N2 fixation, nitrate turbulent diffusion, atmospheric deposition) and leaving the photic layer (particulate N export). The three stations were characterized by a strong nitracline and contrasted deep chlorophyll maximum depths, which were lower in the oligotrophic Melanesian archipelago (MA, stations LD A and LD B) than in the ultra-oligotrophic waters of the South Pacific Gyre (SPG, station LD C). N2 fixation rates were extremely high at both LD A (593 ± 51 µmol N m−2 d−1) and LD B (706 ± 302 µmol N m−2 d−1), and the diazotroph community was dominated by Trichodesmium. N2 fixation rates were lower (59 ± 16 µmol N m−2 d−1) at LD C, and the diazotroph community was dominated by unicellular N2-fixing cyanobacteria (UCYN). At all stations, N2 fixation was the major source of new N (> 90 %) before atmospheric deposition and upward nitrate fluxes induced by turbulence. N2 fixation contributed circa 13–18 % of primary production in the MA region and 3 % in the SPG water and sustained nearly all new primary production at all stations. The e ratio (e ratio = particulate carbon export ∕ primary production) was maximum at LD A (9.7 %) and was higher than the e ratio in most studied oligotrophic regions (< 5 %), indicating a high efficiency of the WTSP to export carbon relative to primary production. The direct export of diazotrophs assessed by qPCR of the nifH gene in sediment traps represented up to 30.6 % of the PC export at LD A, while their contribution was 5 and < 0.1 % at LD B and LD C, respectively. At the three studied stations, the sum of all N input to the photic layer exceeded the N output through organic matter export. This disequilibrium leading to N accumulation in the upper layer appears as a characteristic of the WTSP during the summer season.
Published: 2018
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125. LEADERSHIP, CREATIVITÉ ET ROUTINE DANS LES PETITES ENTREPRISES EN HYPERCROISSANCE

Author: Chanut-Guieu, Cécile, Guieu, Gilles, Dana, Léo Paul, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur le Transport et la Logistique (CRET-LOG), Aix Marseille Université (AMU), Montpellier Research in Management (MRM), Université Montpellier 1 (UM1)-Université Paul-Valéry - Montpellier 3 (UPVM)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université de Perpignan Via Domitia (UPVD)-Groupe Sup de Co Montpellier (GSCM) - Montpellier Business School-Université de Montpellier (UM), Université Paul-Valéry - Montpellier 3 (UPVM)-Université de Perpignan Via Domitia (UPVD)-Groupe Sup de Co Montpellier (GSCM) - Montpellier Business School-Université de Montpellier (UM), Laboratoire d'Economie et de Sociologie du Travail (LEST), and Guieu, Gilles
Subjects: [SHS.GESTION]Humanities and Social Sciences/Business administration, [SHS.GESTION] Humanities and Social Sciences/Business administration, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2017

126. Deux aperçus de la gouvernance. La place du conseil d’administration dans les PME

Author: Chanut-Guieu, Cécile, Gieu, Gilles, Chanut-Guieu, Cécile, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), 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: 2016

127. Stratégies de croissance ou de coopération ? Les enjeux pour l’accueil du jeune enfant

Author: Petrella, Francesca, Richez-Battesti, Nadine, Chanut-Guieu, Cécile, Lhuillier, Vincent, Chanut-Guieu, Cécile, Laurent Gardin, Florence Jany-Catrice, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Lorrain de Sciences Sociales (2L2S), Université de Lorraine (UL), and Laboratoire d'Economie et de Sociologie du Travail (LEST)
Subjects: économie sociale et solidaire, Petite enfance, Economics (General), BUS000000, économie sociale et solidaire ESS, [SHS.GESTION]Humanities and Social Sciences/Business administration, Business, [SHS.ECO]Humanities and Social Sciences/Economics and Finance, Coopération, [SHS.GESTION] Humanities and Social Sciences/Business administration, [SHS.ECO] Humanities and Social Sciences/Economics and Finance, ComputingMilieux_MISCELLANEOUS
Abstract: Introduction Dans le champ de la petite enfance, depuis le milieu des années 2000, les évolutions du contexte institutionnel sont marquées par des changements importants du point de vue de la gouvernance et de la recomposition de l’offre d’accueil sur les territoires. Ces mutations s’inscrivent dans une volonté politique d’augmenter le nombre de places d’accueil, tout en maîtrisant les dépenses publiques. La stratégie retenue est...
Published: 2016
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128. Sources of Cd, Cu, Ni and Zn in Portuguese coastal waters

Author: Cotté-Krief, Marie-Hélène, Guieu, Cécile, Thomas, Alain J, and Martin, Jean-Marie
Published: 2000
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129. Leadership, creativity and routine in small businesses experiencing hyper-growth

Author: Chanut-Guieu, Cécile, primary, Guieu, Gilles, additional, and Dana, Léo-Paul, additional
Published: 2019
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130. Surface ocean microbiota determine cloud precursors.

Author: Sellegri, Karine, Nicosia, Alessia, Freney, Evelyn, Uitz, Julia, Thyssen, Melilotus, Grégori, Gérald, Engel, Anja, Zäncker, Birthe, Haëntjens, Nils, Mas, Sébastien, Picard, David, Saint-Macary, Alexia, Peltola, Maija, Rose, Clémence, Trueblood, Jonathan, Lefevre, Dominique, D'Anna, Barbara, Desboeufs, Karine, Meskhidze, Nicholas, and Guieu, Cécile
Subjects: PHYTOPLANKTON, CLOUD condensation nuclei, EDDY flux, ATMOSPHERIC models, SEAWATER
Abstract: One pathway by which the oceans influence climate is via the emission of sea spray that may subsequently influence cloud properties. Sea spray emissions are known to be dependent on atmospheric and oceanic physicochemical parameters, but the potential role of ocean biology on sea spray fluxes remains poorly characterized. Here we show a consistent significant relationship between seawater nanophytoplankton cell abundances and sea-spray derived Cloud Condensation Nuclei (CCN) number fluxes, generated using water from three different oceanic regions. This sensitivity of CCN number fluxes to ocean biology is currently unaccounted for in climate models yet our measurements indicate that it influences fluxes by more than one order of magnitude over the range of phytoplankton investigated. [ABSTRACT FROM AUTHOR]
Published: 2021
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131. Impact of dust enrichment 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, and Guieu, Cécile
Subjects: MINERAL dusts, ATMOSPHERIC deposition, DUST, OCEAN acidification, TERRITORIAL waters, WATER, COMMUNITIES
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 stratification periods. These areas are expected to expand in the future due to lower nutrient supply from sub-surface waters caused by enhanced stratification, likely further increasing the role of atmospheric deposition as a source of new nutrients to surface waters. Yet, whether plankton communities will react differently to dust deposition in a warmer and acidified environment remains an open question. The impact of dust deposition both in present and future climate conditions was assessed through 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 May/June 2017 in the frame of the PEACETIME project. The experimental protocol comprised two unmodified control tanks, two tanks enriched with a Saharan dust analog and two tanks enriched with the dust analog 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 of the experiments (3-4 d). Here, we present the general setup of the experiments and the impacts of dust seeding and/or future climate change scenario on nutrients and biological stocks. Dust addition led to a rapid and maximum input of nitrate whereas phosphate release from the dust analog was much smaller. 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 in coastal waters. However, interestingly, the effects of dust deposition on biological stocks were highly different between 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. Finally, ocean acidification and warming did not drastically modify the composition of the autotrophic assemblage with all groups positively impacted by warming and acidification, suggesting an exacerbation of effects from atmospheric dust deposition in the future. [ABSTRACT FROM AUTHOR]
Published: 2020
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132. Contrasted release of insoluble elements (Fe, Al, REE, Th, Pa) after dust deposition in seawater: a tank experiment approach.

Author: Roy-Barman, Matthieu, Folio, Lorna, Douville, Eric, Leblond, Nathalie, Gazeau, Frédéric, Bressac, Matthieu, Wagener, Thibaut, Ridame, Céline, Desboeufs, Karine, and Guieu, Cécile
Subjects: DUST, RARE earth metals, DUST control, TANKS, SEAWATER
Abstract: The release of lithogenic elements (which are often assumed to be insoluble) such as Aluminum (Al), Iron (Fe), Rare Earth Elements (REE), Thorium (Th) and Protactinium (Pa) by Saharan dust reaching Mediterranean seawater was studied through tank experiments over 3 to 4 days under controlled conditions including control without dust addition and dust seeding under present and future climate conditions (+3 °C and -0.3 pH unit). Unfiltered surface seawater from 3 oligotrophic regions (Tyrrhenian Sea, Ionian Sea and Algerian Basin) were used. The maximum dissolution fractions were low for all seeding experiments: less than 0.3% for Fe, 1% for [sup 232]Th and Al, about 2-5% for REE 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 REE were scavenged back on the particles after a fast initial release. The constant [sup 230]Th/[sup 232]Th 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 thorium and REE in seawater, leading to a lower Th release and a higher light REE release under increased greenhouse conditions. [ABSTRACT FROM AUTHOR]
Published: 2020
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133. 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, Alesia, 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 (INP) have a large impact on the climate-relevant properties of clouds over the oceans. Studies have shown that sea spray aerosols (SSA), produced upon bursting of bubbles at the ocean surface, can be an important source of marine INP, particularly during periods of enhanced biological productivity. Recent mesocosm experiments using natural seawater spiked with nutrients have revealed that marine INP are derived from two separate classes of organic matter in SSA. Despite this finding, existing parameterizations for marine INP abundance are based solely on single variables such as total organic carbon (TOC) or SSA surface area, which may mask specific trends in the separate classes of INPs. 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 INP that accounts for the two associated classes of organic matter. The PEACETIME cruise took place from May 10 to June 10, 2017 in the Mediterranean Sea. Throughout the cruise, INP concentrations in the surface microlayer (SML) and in SSA 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 SSA was also evaluated. 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 of iron in the SML and bacterial abundances. Increases of INPs in marine SSA (INP[sub SSA]) were not observed before a delay of three days compared to increases in the SML, and are likely a result of a strong influence of bulk SSW INP for the temperatures investigated (T=-18°C for SSA, T=-16°C for SSW). Results confirmed that INPSSA are divided into two classes depending on their associated organic matter. Here we find that warm (T ≥ -22C) INPSSA concentrations are correlated with water soluble organic matter in the SSA, but also to SSW parameters (POCSSW INPSSW,-16C) while cold INPSSA (T < -22C) are correlated with SSA water-insoluble organic carbon (WIOC) and SML dissolved organic carbon (DOC) concentration. A relationship was also found between cold INPSSA and SSW microphytoplankton cell abundances, indicating that these species might be at the origin of water insoluble organic matter with surfactant properties and specific IN properties. Using these results, we propose a two-component parameterization for the abundance of INP in marine SSA and compare it with previous single-component models based on SSA surface area and TOC content. This new, two-component parameterization should improve attempts to incorporate marine INP emissions into numerical models. Future studies will be conducted to confirm if our parameterization can be extended to regions of higher biological productivity, such as the Southern Ocean. [ABSTRACT FROM AUTHOR]
Published: 2020
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134. 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. S. H., Thyssen, Melilotus, Grégori, Gérald, Haëntjens, Nils, Dinasquet, Julie, Obernosterer, Ingrid, Van-Wambeke, France, Engel, Anja, Zäncker, 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 seawater biogeochemical properties for use in models. [ABSTRACT FROM AUTHOR]
Published: 2020
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135. Trichodesmium physiological ecology and phosphate reduction in the western tropical South Pacific

Author: Frischkorn, Kyle R., primary, Krupke, Andreas, additional, Guieu, Cécile, additional, Louis, Justine, additional, Rouco, Mónica, additional, Salazar Estrada, Andrés E., additional, Van Mooy, Benjamin A. S., additional, and Dyhrman, Sonya T., additional
Published: 2018
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136. In-depth characterization of diazotroph activity across the western tropical South Pacific hotspot of N2 fixation (OUTPACE cruise)

Author: Bonnet, Sophie, primary, Caffin, Mathieu, additional, Berthelot, Hugo, additional, Grosso, Olivier, additional, Benavides, Mar, additional, Helias-Nunige, Sandra, additional, Guieu, Cécile, additional, Stenegren, Marcus, additional, and Foster, Rachel Ann, additional
Published: 2018
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137. Modeling the impacts of atmospheric deposition of nitrogen and desert dust-derived phosphorus on nutrients and biological budgets of the Mediterranean Sea

Author: Richon, Camille, primary, Dutay, Jean-Claude, additional, Dulac, François, additional, Wang, Rong, additional, Balkanski, Yves, additional, Nabat, Pierre, additional, Aumont, Olivier, additional, Desboeufs, Karine, additional, Laurent, Benoı̂t, additional, Guieu, Cécile, additional, Raimbault, Patrick, additional, and Beuvier, Jonathan, additional
Published: 2018
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138. Regionalisation of the Mediterranean basin, a MERMEX synthesis

Author: Ayata, Sakina-Dorothée, primary, Irisson, Jean-Olivier, additional, Aubert, Anaïs, additional, Berline, Léo, additional, Dutay, Jean-Claude, additional, Mayot, Nicolas, additional, Nieblas, Anne-Elise, additional, D'Ortenzio, Fabrizio, additional, Palmiéri, Julien, additional, Reygondeau, Gabriel, additional, Rossi, Vincent, additional, and Guieu, Cécile, additional
Published: 2018
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139. Preface of special issue of MERMEX project: Recent advances in the oceanography of the Mediterranean Sea

Author: Sempéré, Richard, primary, Guieu, Cécile, additional, Pairaud, Ivane, additional, and Durrieu de Madron, Xavier, additional
Published: 2018
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140. Peacetime : une campagne inédite associant physico-chimistes de l’atmosphère et biogéochimistes marins

Author: Desboeufs, Karine, Guieu, Cécile, Desboeufs, Karine, and Guieu, Cécile
Abstract: Le projet Peacetime a pour but d’étudier les processus à l’interface air-mer en Méditerranée, région du monde où les apports atmosphériques jouent un rôle clé comme source de nutriments pour la biosphère marine. Cette campagne devrait permettre aux scientif iques de mieux comprendre comment les dépôts atmosphériques modif ient le fonctionnement de l’écosystème pélagique aujourd’hui et dans le futur afin de prévoir plus précisément le rôle des changements climatiques sur la biodiversité enMéditerranée.
Published: 2018
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141. Regionalisation of the Mediterranean basin, a MERMEX synthesis

Author: European Commission, Ayata, Sakina-Dorothée, Irisson, Jean-Olivier, Aubert, Anaïs, Berline, Léo, Dutay, Jean-Claude, Mayot, Nicolas, Nieblas, Anne-Elise, D'Ortenzio, Fabrizio, Palmiéri, Julien, Reygondeau, Gabriel, Rossi, Vincent, Guieu, Cécile, European Commission, Ayata, Sakina-Dorothée, Irisson, Jean-Olivier, Aubert, Anaïs, Berline, Léo, Dutay, Jean-Claude, Mayot, Nicolas, Nieblas, Anne-Elise, D'Ortenzio, Fabrizio, Palmiéri, Julien, Reygondeau, Gabriel, Rossi, Vincent, and Guieu, Cécile
Abstract: Regionalisation aims at delimiting provinces within which physical conditions, chemical properties, and biological communities are reasonably homogeneous. This article proposes a synthesis of the many recent regionalisations of the open-sea regions of the Mediterranean Sea. The nine studies considered here defined regions based on different, and sometimes complementary, criteria: dynamics of surface chlorophyll concentration, ocean currents, three-dimensional hydrological and biogeochemical properties, or the distribution of organisms. Although they identified different numbers and patterns of homogeneous regions, their compilation in the epipelagic zone identifies nine consensus frontiers, eleven consensus regions with relatively homogeneous conditions, and four heterogeneous regions with highly dynamical conditions. The consensus frontiers and regions are in agreement with well-known hydrodynamical features of the Mediterranean Sea, which constrain the distribution of hydrological and ecological variables. The heterogeneous regions are rather defined by intense mesoscale activity. The synthesis proposed here could constitute a reference step for management actions and spatial planning, such as the application of the European Marine Strategy Framework Directive, and for future biogeochemical and ecological studies in the Mediterranean Sea.
Published: 2018

142. L’entrepreneur visionnaire au cœur de l’hypercroissance

Author: Chanut-Guieu, Cécile, Guieu, Gilles, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur le Transport et la Logistique (CRET-LOG), Aix Marseille Université (AMU), ANR-07-ENTR-0008,HYPERCROIS,Les entreprises moyennes en hyper croissance : trajectoires et temporalités(2007), Laboratoire d'Economie et de Sociologie du Travail (LEST), Chanut-Guieu, Cécile, and Entreprises et formes d'organisation économique - Les entreprises moyennes en hyper croissance : trajectoires et temporalités - - HYPERCROIS2007 - ANR-07-ENTR-0008 - ENTR - VALID
Subjects: Hypercroissance, Vision, Entrepreneur, [SHS] Humanities and Social Sciences, High growth, Visionnaire, [SHS]Humanities and Social Sciences
Abstract: International audience; Les PME en « hypercroissance » constituent un enjeu tant scientifique qu’économique. Ces entreprises singulières,dont la taille double en quatre ans, méritent une attention particulière. Les dirigeants sont souventau coeur du processus de croissance. La réflexion des auteurs envisage la construction de la croissancecomme la résultante du caractère visionnaire de l’entrepreneur. À partir de 39 entretiens avec les dirigeantsde huit PME en hypercroissance, ils proposent une structuration en trois volets du concept d’entrepreneurvisionnaire. L’entrepreneur doit avoir une réelle volonté d’entreprendre, se fonder sur l’expérience et rendreles circonstances favorables.
Published: 2015

143. Experimental evidence of formation of transparent exopolymer particles (TEP) and POC export provoked by dust addition under current and high pCO2 conditions

Author: Louis, Justine, Pedrotti, Maria Luiza, Gazeau, Frédéric, Guieu, Cécile, Département Génie Biologique / IUT de Saint-Brieuc, Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), Laboratoire d'océanographie de Villefranche (LOV), Observatoire océanologique de Villefranche-sur-mer (OOVM), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), IUT de Saint-Brieuc, Université de Rennes (UR), and Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Atmospheric Science, Carbon Sequestration, Environmental Engineering, Materials by Structure, Polymers, Materials Science, lcsh:Medicine, Oceanography, Sea Water, Bodies of water, Oceans, Mediterranean Sea, Pressure, Environmental Chemistry, Seawater, Organic Chemicals, Particle Size, lcsh:Science, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, Petrology, Sedimentary Geology, Ocean Acidification, Ecology and Environmental Sciences, lcsh:R, Dust, Geology, Carbon Dioxide, Hydrogen-Ion Concentration, Marine and aquatic sciences, Chemistry, Particulates, Atmospheric Chemistry, Mixtures, Physical Sciences, Earth Sciences, Engineering and Technology, Sediment, lcsh:Q, Antacids, Hydrology, Acid Deposition, Research Article
Abstract: International audience; The evolution of organic carbon export to the deep ocean, under anthropogenic forcing such as ocean warming and acidification, needs to be investigated in order to evaluate potential positive or negative feedbacks on atmospheric CO 2 concentrations, and therefore on climate. As such, modifications of aggregation processes driven by transparent exopolymer particles (TEP) formation have the potential to affect carbon export. The objectives of this study were to experimentally assess the dynamics of organic matter, after the simulation of a Saharan dust deposition event, through the measurement over one week of TEP abundance and size, and to evaluate the effects of ocean acidification on TEP formation and carbon export following a dust deposition event. Three experiments were performed in the laboratory using 300 L tanks filled with filtered seawater collected in the Mediterranean Sea, during two 'no bloom' periods (spring at the start of the stratification period and autumn at the end of this stratification period) and during the winter bloom period. For each experiment, one of the two tanks was acidified to reach pH conditions slightly below values projected for 2100 (~ 7.6–7.8). In both tanks, a dust deposition event of 10 g m-2 was simulated at the surface. Our results suggest that Saharan dust deposition triggered the abiotic formation of TEP, leading to the formation of organic-mineral aggregates. The amount of particulate organic carbon (POC) exported was proportional to the flux of lithogenic particles to the sediment traps. Depending on the season, the POC flux following artificial dust deposition ranged between 38 and 90 mg m-2 over six experimental days. Such variability is likely linked to the seasonal differences in the quality and quantity of TEP-precursors initially present in seawater. Finally, these export fluxes were not significantly different at the completion of the three experiments between the two pH conditions.
Published: 2017
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144. Note de lecture de Cossette, Pierre (2016), Publier dans une revue savante, Québec : Presses de l’Université du Québec, 2ème édition

Author: Chanut-Guieu, Cécile, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire d'Economie et de Sociologie du Travail (LEST)
Subjects: JEL: M - Business Administration and Business Economics • Marketing • Accounting • Personnel Economics/M.M0 - General, Publish, Research, [SHS.GESTION]Humanities and Social Sciences/Business administration, Recherche, Academic journals, Revue savante, Publier, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2017
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145. Deux aperçus de la gouvernance

Author: Chanut-Guieu, Cécile, Guieu, Gilles, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur le Transport et la Logistique (CRET-LOG), and Aix Marseille Université (AMU)
Subjects: gouvernance, [SHS.GESTION]Humanities and Social Sciences/Business administration, pme, petite enfance, conseil d'administration
Abstract: Conférence invitée au séminaire externe, axe 3, laboratoire Coactis Lyon II - Saint-Etienne; International audience
Published: 2016

146. Formes et stratégies de croissance dans le champ de l’accueil du jeune enfant : vers de nouveaux modèles d’organisation ?

Author: Petrella, Francesca, Richez-Battesti, Nadine, Chanut-Guieu, Cécile, Lhuillier, Vincent, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Lorrain de Sciences Sociales (2L2S), Université de Lorraine (UL), Chanut-Guieu, Cécile, and Laboratoire d'Economie et de Sociologie du Travail (LEST)
Subjects: Modèle d'organisation, Structures petite enfance, [SHS.GESTION]Humanities and Social Sciences/Business administration, Gouvernance, [SHS.GESTION] Humanities and Social Sciences/Business administration, [SHS.ECO] Humanities and Social Sciences/Economics and Finance, Stratégies de croissance, [SHS.ECO]Humanities and Social Sciences/Economics and Finance
Abstract: International audience; Dans le champ de la petite enfance et depuis le milieu des années 2000, les évolutions du contexte institutionnel sont marquées par des changements importants du point de vue de la gouvernance et de la recomposition de l’offre d’accueil sur les territoires. Ces changements s’inscrivent dans une volonté politique d’augmenter le nombre de places d’accueil, tout en maîtrisant les dépenses publiques. On assiste à une diversification accrue de l’offre d’accueil, tant du point de vue des modes d’accueil (passage au multi-accueil, création récente des micro-crèches et des maisons d’assistantes maternelles, …), que des gestionnaires.Cette communication vise à mieux comprendre les stratégies de coordination mises en oeuvre par les acteurs de l’ESS en particulier par rapport à celles qu'adoptent les acteurs privés lucratifs. Deux grandes stratégies de coordination ont en effet été identifiées : une stratégie de croissance et une stratégie de coopération par un maillage en réseau.
Published: 2014

147. Diversité des opérateurs et gouvernance locale de la petite enfance : quels enjeux pour le développement des territoires, les modes d'organisation des acteurs et la régulation de la qualité ?

Author: Chanut-Guieu, Cécile, Petrella, Francesca, Richez-Battesti, Nadine, Lhuillier, Vincent, Laurent, Antoinette, Laboratoire d'Economie et de Sociologie du Travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Lorrain de Sciences Sociales (2L2S), Université de Lorraine (UL), Caisse nationale des allocations familiales (CNAF), Laboratoire d'économie et sociologie du travail (LEST), Laboratoire Lorrain des Sciences Sociales (2L2S), Laboratoire d'économie et de sociologie du travail (LEST), and Chanut-Guieu, Cécile
Subjects: [QFIN]Quantitative Finance [q-fin], Territoires, Conciliation vie familiale/vie professionnelle, [SHS.ECO]Humanities and Social Sciences/Economics and Finance, [SHS]Humanities and Social Sciences, Crêche, Petite enfance, Acteur public, Jeunes enfants, Gouvernance territoire, Professionnalisation du secteur, Travail des femmes, Marchandisation, [SHS.GESTION]Humanities and Social Sciences/Business administration, Gouvernance, France, [SHS.ECO] Humanities and Social Sciences/Economics and Finance, [SHS.GESTION] Humanities and Social Sciences/Business administration, Garde des jeunes enfants, régulation de la qualité, Secteur de la petite enfance
Abstract: Rapport sous la direction de Francesca Petrella et Nadine Richez-Battesti (LEST UMR 73&7); L’accueil des jeunes enfants se trouve, tant en France que dans de nombreux pays européens, au centre de préoccupations sociales et économiques, telles que la conciliation entre vie familiale et vie professionnelle, l’articulation entre aides formelle et informelle ou l’égalité entre les genres. Les services d’accueil ont dû faire face à l’accroissement et à la diversification des demandes suite aux évolutions démographiques, aux transformations des structures familiales ainsi qu’aux exigences croissantes de flexibilité sur le marché du travail. Sans nier les spécificités françaises, nous pouvons dire que ces services connaissent, tout comme les services d’aide aux personnes âgées et ce, dans la plupart des pays européens, selon des modalités et des degrés variés, une « défamilialisation », i.e. une externalisation de la garde d’enfants en dehors de la famille avec une professionnalisation des activités qui y sont associées, d’une part, et une « marchandisation » de ces services d’autre part (Laville, Nyssens, 2001). Par marchandisation, nous entendons à la fois le fait qu’il y ait une rémunération du travail de prise en charge de la personne (enfant en bas âge ou personne âgée), qu’un « marché » des services se structure dans plusieurs pays notamment à travers la multiplication des appels d’offre et que le développement de ces services est encouragé par des mesures de soutien de la demande, laissant aux usagers le choix duprestataire et encourageant potentiellement la concurrence entre prestataires. [...]
Published: 2014

148. L’entrepreneur visionnaire. Une analyse à partir des discours des dirigeants des PME en hypercroissance

Author: Chanut-Guieu, Cécile, Guieu, Gilles, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur le Transport et la Logistique (CRET-LOG), Aix Marseille Université (AMU), ANR-07-ENTR-0008,HYPERCROIS,Les entreprises moyennes en hyper croissance : trajectoires et temporalités(2007), Laboratoire d'Economie et de Sociologie du Travail (LEST), Chanut-Guieu, Cécile, and Entreprises et formes d'organisation économique - Les entreprises moyennes en hyper croissance : trajectoires et temporalités - - HYPERCROIS2007 - ANR-07-ENTR-0008 - ENTR - VALID
Subjects: Hypergrowth, Hypercroissance, Vision, Entrepreneur, [SHS.GESTION]Humanities and Social Sciences/Business administration, Pme, [SHS.GESTION] Humanities and Social Sciences/Business administration, JEL: M - Business Administration and Business Economics • Marketing • Accounting • Personnel Economics/M.M1 - Business Administration, Small business, Visionnaire
Abstract: Hyper-growth small businesses constitute both a scientific and an economic interest. These small businesses are peculiar, and need the attention of the academy. This proposal aims at examining the construction of growth as the consequence of the visionary nature of the entrepreneur. From 39 interviews with entrepreneurs of eight hyper-growth SBs, we propose a 3-fold structuring of the concept of visionary entrepreneur: The entrepreneur must have the will to create and undertake actions, must build on experience, must make the circumstances favorable. We then integrate the visionary entrepreneur in an integrated model of entrepreneurial management for hypergrowth., Les PME en hypercroissance constituent un enjeu tant scientifique qu’économique. Ces PME sont en effet particulières, et méritent une attention particulière. Cette proposition vise à examiner la construction de la croissance comme la résultante du caractère visionnaire de l’entrepreneur. A partir de 39 entretiens avec les dirigeants de huit PME en hypercroissance, nous proposons une structuration en trois volets du concept d’entrepreneur visionnaire : l’entrepreneur doit avoir la volonté d’entreprendre, doit se fonder sur l’expérience, doit rendre les circonstances favorables. Nous intégrons ensuite l’entrepreneur visionnaire dans un modèle intégré de gestion entrepreneuriale de l’hypercroissance.
Published: 2014

149. Board of directors in SMEs: A review and research agenda. A re-examination of the topic 15 years after Morten Huse (ERD 2000) review

Author: Chanut-Guieu, Cécile, Guieu, Gilles, Laboratoire d'économie et de sociologie du travail (LEST), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche sur le Transport et la Logistique (CRET-LOG), Aix Marseille Université (AMU), University of St.Gallen – Swiss Research Institute of Small Business and Entrepreneurship | KMU-HSG, Guieu, Gilles, and Laboratoire d'Economie et de Sociologie du Travail (LEST)
Subjects: Governance, Board of Directors, Research agenda, SMEs, Review, JEL: M - Business Administration and Business Economics • Marketing • Accounting • Personnel Economics/M.M1 - Business Administration/M.M1.M12 - Personnel Management • Executives, Executive Compensation, JEL: M - Business Administration and Business Economics • Marketing • Accounting • Personnel Economics/M.M1 - Business Administration, boards of directors, research agenda, JEL: G - Financial Economics/G.G3 - Corporate Finance and Governance/G.G3.G34 - Mergers • Acquisitions • Restructuring • Corporate Governance, [SHS.GESTION]Humanities and Social Sciences/Business administration, [SHS.GESTION] Humanities and Social Sciences/Business administration, Family firms, Small business
Abstract: International audience; Morten Huse was invited editor for an Entrepreneurship & Regional Development special issue on ‘Boards of directors in SMEs’, gathering four papers on the topic (Fiegener et al., 2000; Gabrielsson and Winlund, 2000; Johannisson and Huse, 2000; Sapienza et al., 2000). In the first sentence of his introducting review article, Huse noted: “While boards of directors in small and medium-sized enterprises (SMEs) received little attention in research, teaching and practice a few years ago, this has now changed” (Huse, 2000: 271). How far has it changed between 2000 and mid-2016? This is the question we raised in order to examine the literature published from the beginning of the century to now (June 2016). Has research on boards in SMEs expanded, could we identify a growing trend, as suggested by Huse in 2000? If the answer is positive, what are the main traits of this literature? Are publications and their authors tightly linked (what could be considered as a field) or, as Huse noted in 2000, are papers only loosely connected?Drawing on Huse objectives in his review, the objectives of our paper are (1) to identify what has been published in the main SME (but also general management and corporate governance) journals, (2) to analyse the methods, theories, and contributions of publications about boards in SMEs, (3) to draw a cartography of references used by these publications and, (4) present the intellectual changes on the topic in the period. Of course, as Huse did, we also want “to stimulate and direct further research about boards of directors in SMEs. For that purpose, we gathered 107 “boards in SMEs or family firms” articles published from 2000 to 2016 in peer-reviewed journals, and present here the first results of our analysis.
Published: 2016

150. In depth characterization of diazotroph activity across the Western Tropical South Pacific hot spot of N2 fixation

Author: Bonnet, Sophie, primary, Caffin, Mathieu, additional, Berthelot, Hugo, additional, Grosso, Olivier, additional, Benavides, Mar, additional, Helias-Nunige, Sandra, additional, Guieu, Cécile, additional, Stenegren, Marcus, additional, and Foster, Rachel A., additional
Published: 2018
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