Consulta: creatorFacets:"Guieu, Cécile"
Registros recuperados: 9
Data/hora: 08/06/2024 17:38:13

Impact of dust addition on the metabolism of Mediterranean plankton communities and carbon export under present and future conditions of pH and temperature
Provedor de dados: 5
Autores: Gazeau, Frédéric; Van Wambeke, France; Maranon, Emilio; Perez-lorenzo, Maria; Alliouane, Samir; Stolpe, Christian; Blasco, Thierry; Leblond, Nathalie; Zancker, Birthe; Engel, Anja; Marie, Barbara; Dinasquet, Julie; Guieu, Cécile.
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 in the Algerian basin (FAST) onboard the R/V “Pourquoi Pas?” in late spring 2017. For each experiment, six tanks...
Tipo: Text
Palavras-chave: Mediterranean Sea; Atmospheric deposition; Plankton community metabolism; Carbon export; Ocean acidification; Ocean warming.
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00688/79967/82900.pdf

Characterising the surface microlayer in the Mediterranean Sea: trace metals concentration and microbial plankton abundance
Provedor de dados: 5
Autores: 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.
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...
Tipo: Text
Ano: 2019
URL: https://archimer.ifremer.fr/doc/00590/70254/68302.pdf

Influence of atmospheric deposition on biogeochemical cycles in an oligotrophic ocean system
Provedor de dados: 5
Autores: Van Wambeke, France; Taillandier, Vincent; Deboeufs, Karine; Pullido-villena, Elvira; Dinasquet, Julie; Engel, Anja; Maranon, Emilio; Ridame, Céline; Guieu, Cécile.
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...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00659/77153/78527.pdf

Contribution of electroactive humic substances to the iron-binding ligands released during microbial remineralisation of sinking particles
Provedor de dados: 5
Autores: Whitby, Hannah; Bressac, Matthieu; Sarthou, Geraldine; Ellwood, Michael J.; Guieu, Cécile; Boyd, Philip W.
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...
Tipo: Text
Palavras-chave: Iron; Ligand; Humic; Remineralisation; Particle; Degradation.
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00618/72981/72055.pdf

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)
Provedor de dados: 5
Autores: Guieu, Cécile; D'Ortenzio, Fabrizio; Dulac, François; Taillandier, Vincent; Doglioli, Andrea; Petrenko, Anne; Barrillon, Stéphanie; Mallet, Marc; Nabat, Pierre; Desboeufs, Karine.
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...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00611/72340/71224.pdf

Impact of dust enrichment on Mediterranean plankton communities under present and future conditions of pH and temperature: an experimental overview
Provedor de dados: 5
Autores: 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.
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....
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00688/80015/82994.pdf

Mediterranean nascent sea spray organic aerosol and relationships with seawater biogeochemistry
Provedor de dados: 5
Autores: 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.
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...
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00688/80017/82995.pdf

Surface ocean microbiota determine cloud precursors
Provedor de dados: 5
Autores: 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; Guieu, Cécile; Law, Cliff S.
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...
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00669/78077/80312.pdf

Contrasted release of insoluble elements (Fe, Al, rare earth elements, Th, Pa) after dust deposition in seawater: a tank experiment approach
Provedor de dados: 5
Autores: Roy-barman, Matthieu; Foliot, Lorna; Douville, Eric; Leblond, Nathalie; Gazeau, Frédéric; Bressac, Matthieu; Wagener, Thibaut; Ridame, Céline; Desboeufs, Karine; Guieu, Cécile.
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...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00642/75456/76274.pdf