Consulta: creatorFacets:"Desboeufs, Karine"
Registros recuperados: 7
Data/hora: 08/06/2024 19:09:04

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

Potential bioavailability of organic matter from atmospheric particles to marine heterotrophic bacteria
Provedor de dados: 5
Autores: Djaoudi, Kahina; Van Wambeke, France; Barani, Aude; Bhairy, Nagib; Chevaillier, Servanne; Desboeufs, Karine; Nunige, Sandra; Labiadh, Mohamed; Des Tureaux, Thierry Henry; Lefevre, Dominique; Nouara, Amel; Panagiotopoulos, Christos; Tedetti, Marc; Pulido-villena, Elvira.
The surface ocean receives important amounts of organic carbon from atmospheric deposition. The degree of bioavailability of this source of organic carbon will determine its impact on the marine carbon cycle. In this study, the potential availability of dissolved organic carbon (DOC) leached from both desert dust and anthropogenic aerosols to marine heterotrophic bacteria was investigated. The experimental design was based on 16 d incubations, in the dark, of a marine bacterial inoculum into artificial seawater amended with water-soluble Saharan dust (D treatment) and anthropogenic (A treatment) aerosols, so that the initial DOC concentration was similar between treatments. Glucose-amended (G) and non-amended (control) treatments were run in parallel. Over...
Tipo: Text
Ano: 2020
URL: https://archimer.ifremer.fr/doc/00677/78941/81326.pdf

Iron from a submarine source impacts the productive layer of the Western Tropical South Pacific (WTSP)
Provedor de dados: 5
Autores: Guieu, Cecile; Bonnet, Sophie; Petrenko, Anne; Menkes, Christophe; Chavagnac, Valerie; Desboeufs, Karine; Maes, Christophe; Moutin, Thierry.
In the Western Tropical South Pacific, patches of high chlorophyll concentrations linked to the occurrence of N2-fixing organisms are found in the vicinity of volcanic islands. The survival of these organisms relies on a high bioavailable iron supply whose origin and fluxes remain unknown. Here, we measured high dissolved iron (DFe) concentrations (up to 66 nM) in the euphotic layer, extending zonally over 10 degrees longitude (174 E−175 W) at ∼20°S latitude. DFe atmospheric fluxes were at the lower end of reported values of the remote ocean and could not explain the high DFe concentrations measured in the water column in the vicinity of Tonga. We argue that the high DFe concentrations may be sustained by a submarine source, also characterized by...
Tipo: Text
Ano: 2018
URL: https://archimer.ifremer.fr/doc/00444/55564/57174.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

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