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| Registros recuperados: 12 | |
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| Eichinger, M.; Sempere, R.; Gregori, G.; Charriere, B.; Poggiale, J. C.; Lefevre, D.. |
| This paper assesses how considering variation in DOC availability and cell maintenance in bacterial models affects Bacterial Growth Efficiency (BGE) estimations. For this purpose, we conducted two biodegradation experiments simultaneously. In experiment one, a given amount of substrate was added to the culture at the start of the experiment whilst in experiment two, the same amount of substrate was added, but using periodic pulses over the time course of the experiment. Three bacterial models, with different levels of complexity, (the Monod, Marr-Pirt and the dynamic energy budget - DEB - models), were used and calibrated using the above experiments. BGE has been estimated using the experimental values obtained from discrete samples and from model... |
| Tipo: Text |
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| Ano: 2010 |
URL: https://archimer.ifremer.fr/doc/00372/48311/48417.pdf |
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| Carlotti, F.; Jouandet, M. -p.; Nowaczyk, A.; Harmelin-vivien, M.; Lefevre, D.; Richard, P.; Zhu, Y.; Zhou, M.. |
| This paper presents results on the spatial and temporal distribution patterns of mesozooplankton in the naturally fertilized region to the east of the Kerguelen Islands (Southern Ocean) visited at early bloom stage during the KEOPS2 survey (15 October to 20 November 2011). The aim of this study was to compare the zooplankton response in contrasted environments localized over the Kerguelen Plateau in waters of the east shelf and shelf edge and in productive oceanic deep waters characterized by conditions of complex circulation and rapidly changing phytoplankton biomass. The mesozooplankton community responded to the spring bloom earlier on the plateau than in the oceanic waters, where complex mesoscale circulation stimulated initial more or less ephemeral... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00296/40719/39720.pdf |
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| Cavagna, A. J.; Fripiat, F.; Elskens, M.; Mangion, P.; Chirurgien, L.; Closset, I.; Lasbleiz, M.; Florez-leiva, L.; Cardinal, D.; Leblanc, K.; Fernandez, C.; Lefevre, D.; Oriol, L.; Blain, S.; Queguiner, B.; Dehairs, F.. |
| Although the Southern Ocean is considered a high-nutrient, low-chlorophyll (HNLC) area, massive and recurrent blooms are observed over and downstream of the Kerguelen Plateau. This mosaic of blooms is triggered by a higher iron supply resulting from the interaction between the Antarctic Circumpolar Current and the local bathymetry. Net primary production, N uptake (NO3− and NH4+), and nitrification rates were measured at eight stations in austral spring 2011 (October–November) during the KEOPS 2 cruise in the Kerguelen Plateau area. Natural iron fertilization stimulated primary production, with mixed layer integrated net primary production and growth rates much higher in the fertilized areas (up to 315 mmol C m−2 d−1 and up to 0.31 d−1 respectively)... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00294/40561/39448.pdf |
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| Coppola, L.; Prieur, L.; Taupier-letage, I.; Estournel, C.; Testor, P.; Lefevre, D.; Belamari, S.; Le Reste, Serge; Taillandier, V.. |
| During the winter 2013, an intense observation and monitoring was performed in the north-western Mediterranean Sea to study deep water formation process that drives thermohaline circulation and biogeochemical processes (HYMEX SOP2 and DEWEX projects). To observe intensively and continuously the impact of deep convection on oxygen (O2) ventilation, an observation strategy was based on the enhancement of the Argo-O2 floats to monitor the offshore dense water formation area (DWF) in the Gulf of Lion prior to and at the end of the convective period (December 2012 to April 2013). The intense O2 measurements performed through shipborne CTD casts and Argo-O2 floats deployment revealed an O2 inventory rapidly impacted by mixed layer (ML) deepening on the month... |
| Tipo: Text |
Palavras-chave: Dense water formation; North-western Mediterranean Sea; Dissolved oxygen; Argo floats; Deep water ventilation. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00395/50594/51311.pdf |
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| Christaki, U.; Lefevre, D.; Georges, C.; Colombet, J.; Catala, P.; Courties, C.; Sime-ngando, T.; Blain, S.; Obernosterer, I.. |
| Microbial food web dynamics were determined during the onset of several spring phytoplankton blooms induced by natural iron fertilization off Kerguelen Island in the Southern Ocean (KEOPS2). The abundances of heterotrophic bacteria and heterotrophic nanoflagellates, bacterial heterotrophic production, bacterial respiration, and bacterial growth efficiency, were consistently higher in surface waters of the iron-fertilized sites than at the reference site in HNLC (high nutrient low chlorophyll) waters. The abundance of virus-like particles remained unchanged, but viral production increased by a factor of 6 in iron-fertilized waters. Bacterial heterotrophic production was significantly related to heterotrophic nanoflagellate abundance and viral production... |
| Tipo: Text |
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| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00291/40208/38996.pdf |
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| Christaki, U.; Van Wambeke, France; Lefevre, D.; Lagaria, A.; Prieur, L.; Pujo-pay, M.; Grattepanche, J. -d.; Colombet, J.; Psarra, S.; Dolan, J. R.; Sime-ngando, T.; Conan, Pascal; Weinbauer, M. G.; Moutin, T.. |
| The abundance and activity of the major members of the heterotrophic microbial community - from viruses to ciliates - were studied along a longitudinal transect across the Mediterranean Sea in the summer of 2008. The Mediterranean Sea is characterized by a west to east gradient of deepening of DCM (deep chlorophyll maximum) and increasing oligotrophy reflected in gradients of biomass and production. However, within this well documented longitudinal trend, hydrological mesoscale features exist and likely influence microbial dynamics. Here we present data from a W-E transect of 17 stations during the period of summer stratification. Along the transect the production and fate of organic matter was investigated at three selected sites each one located in the... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24400/22422.pdf |
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| Van Haren, H.; Taupier-letage, I.; Aguilar, J. A.; Albert, A.; Anghinolfi, M.; Anton, G.; Anvar, S.; Ardid, M.; Assis Jesus, A. C.; Astraatmadja, T.; Aubert, J. -j.; Auer, R.; Baret, B.; Basa, S.; Bazzotti, M.; Bertin, V.; Biagi, S.; Bigongiari, C.; Bou-cabo, M.; Bouwhuis, M. C.; Brown, A.; Brunner, J.; Busto, J.; Camarena, F.; Capone, A.; Carminati, G.; Carr, J.; Castel, D.; Castorina, E.; Cavasinni, V.; Cecchini, S.; Charvis, Ph.; Chiarusi, T.; Circella, M.; Coniglione, R.; Costantini, H.; Cottini, N.; Coyle, P.; Curtil, C.; De Bonis, G.; Decowski, M. P.; Dekeyser, I.; Deschamps, Anne; Distefano, C.; Donzaud, C.; Dornic, D.; Drouhin, D.; Eberl, T.; Emanuele, U.; Ernenwein, J. -p.; Escoffier, S.; Fehr, F.; Flaminio, V.; Fratini, K.; Fritsch, U.; Fuda, J. -l.; Giacomelli, G.; Gomez-gonzalez, J. P.; Graf, K.; Guillard, G.; Halladjian, G.; Hallewell, G.; Heijboer, A. J.; Hello, Y.; Hernandez-rey, J. J.; Hoessl, J.; De Jong, M.; Kalantar-nayestanaki, N.; Kalekin, O.; Kappes, A.; Katz, U.; Kooijman, P.; Kopper, C.; Kouchner, A.; Kretschmer, W.; Lahmann, R.; Lamare, P.; Lambard, G.; Larosa, G.; Laschinsky, H.; Lefevre, D.; Lelaizant, G.; Lim, G.; Lo Presti, D.; Loehner, H.; Loucatos, S.; Lucarelli, F.; Lyons, K.; Mangano, S.; Marcelin, M.; Margiotta, A.; Martinez-mora, J. A.; Maurin, G.; Mazure, A.; Melissas, M.; Montaruli, T.; Morganti, M.; Moscoso, L.; Motz, H.; Naumann, C.; Neff, M.; Ostasch, R.; Palioselitis, G.; Pavalas, G. E.; Payre, P.; Petrovic, J.; Piattelli, P.; Picot-clemente, N.; Picq, C.; Pillet, R.; Popa, V.; Pradier, T.; Presani, E.; Racca, C.; Radu, A.; Reed, C.; Riccobene, G.; Richardt, C.; Rujoiu, M.; Russo, G. V.; Salesa, F.; Schoeck, F.; Schuller, J. -p.; Shanidze, R.; Simeone, F.; Spurio, M.; Steijger, J. J. M.; Stolarczyk, Th.; Tamburini, C.; Tasca, L.; Toscano, S.; Vallage, B.; Van Elewyck, V.; Vecchi, M.; Vernin, P.; Wijnker, G.; De Wolf, E.; Yepes, H.; Zaborov, D.; Zornoza, J. D.; Zuniga, J.. |
| An Acoustic Doppler Current Profiler (ADCP) was moored at the deep-sea site of the ANTARES neutrino telescope near Toulon, France, thus providing a unique opportunity to compare high-resolution acoustic and optical observations between 70 and 170 m above the sea bed at 2475 m. The ADCP measured downward vertical currents of magnitudes up to 0.03 m s(-1) in late winter and early spring 2006. In the same period, observations were made of enhanced levels of acoustic reflection, interpreted as suspended particles including zooplankton, by a factor of about 10 and of horizontal currents reaching 0.35 m s(-1). These observations coincided with high light levels detected by the telescope, interpreted as increased bioluminescence. During winter 2006 deep... |
| Tipo: Text |
Palavras-chave: Acoustic ADCP observations; Optical photo-multiplier observations; Deep Mediteranean; ANTARES neutrino telescope; Episodic downward current; Bioluminescence; Dense water formation; Northern boundary current. |
| Ano: 2011 |
URL: https://archimer.ifremer.fr/doc/00303/41412/40598.pdf |
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| Leon, Pierre; Drogou, Jean-francois; Chenot, Damien; Leveque, C.; Martinossi, Henri; Massol, Alain; Rigaud, Vincent; Santarelli, Dominique; Valdy, Pierre; Gojak, Carl; Bernardet, Karim; Hafidi, Zouhir; Lenault, Yannick; Mahiouz, Karim; Deschamps, Anne; Hello, Y.; Lefevre, D.; Tamburini, C.; Destelle, J. J.. |
| Recently the ANTARES Neutrino telescope's Infrastructure in the deep Mediterranean Sea, has been extended by a Secondary Junction Box. The main emphasis has been to provide basic power and communications capability for new scientific cabled observatories. This new infrastructure provides unprecedented amounts of power and two-way bandwidth to access and control instrument networks in the oceans. This new development allows cabled observatory to connect the seafloor to the Internet via real-time, two-way highspeed communications. This design gives researchers new capabilities beyond the reach of traditional oceanography. Ocean scientists can run deep-water experiments from labs and universities anywhere around the world. Three different underwater... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00050/16173/13658.pdf |
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| Jacquet, Shm; Dehairs, F.; Lefevre, D.; Cavagna, A. J.; Planchon, F.; Christaki, U.; Monin, L.; Andre, L.; Closset, I.; Cardinal, D.. |
| We report on the zonal variability of mesopelagic particulate organic carbon remineralization and deep carbon transfer potential during the Kerguelen Ocean and Plateau compared Study 2 expedition (KEOPS 2; October-November 2011) in an area of the polar front supporting recurrent massive blooms from natural Fe fertilization. Mesopelagic carbon remineralization (MR) was assessed using the excess, non-lithogenic particulate barium (Ba-xs) inventories in mesopelagic waters and compared with bacterial production (BP), surface primary production (PP) and export production (EP). Results for this early season study are compared with the results obtained during a previous study (2005; KEOPS 1) for the same area at a later stage of the phytoplankton bloom. Our... |
| Tipo: Text |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00260/37140/35670.pdf |
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| Schroeder, K.; Millot, C.; Bengara, L.; Ben Ismail, Sana; Bensi, Manuel; Borghini, M.; Budillon, G.; Cardin, Vanessa; Coppola, Laurent; Curtil, Colin; Drago, Aldo; El Moumni, B.; Font, J.; Fuda, Jean-luc; Garcia-lafuente, J.; Gasparini, G. P.; Kontoyiannis, H.; Lefevre, D.; Puig, P.; Raimbault, Patrick; Rougier, Gilles; Salat, J.; Sammari, Cherif; Sanchez Garrido, J. C.; Sanchez-roman, A.; Sparnocchia, Stefania; Tamburini, C.; Taupier-letage, Isabelle; Theocharis, A.; Vargas-yanez, M.; Vetrano, Anna. |
| The long-term monitoring of basic hydrological parameters (temperature and salinity), collected as time series with adequate temporal resolution (i.e. with a sampling interval allowing the resolution of all important timescales) in key places of the Mediterranean Sea (straits and channels, zones of dense water formation, deep parts of the basins), constitute a priority in the context of global changes. This led CIESM (The Mediterranean Science Commission) to support, since 2002, the HYDROCHANGES programme (www.ciesm.org/marine/programs/hydrochanges.htm), a network of autonomous conductivity, temperature, and depth (CTD) sensors, deployed on mainly short and easily manageable subsurface moorings, within the core of a certain water mass. The HYDROCHANGES... |
| Tipo: Text |
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| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00217/32783/31246.pdf |
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| Mousseau, L.; Lefevre, D.; Narcy, F.; Nival, P.; Andersen, V.. |
| The cruise project was designed to study temporal variations of the ecosystem during the summer-autumn transition and focused on the part played by zooplankton as top-down controllers, and the relative importance of top-down versus bottom-up controls. Zooplankton should play a key role both in the vertical transfer of particulate organic matter and in the mineralisation of organic matter. Although the importance of species diversity is well recognized, the impact of diversity on carbon fluxes is rarely considered. Trophic roles of zooplankton range from strict herbivory to strict carnivory, with all possible combinations (i.e. omnivory) between these two extremes. Feeding strategies are also very diverse, for example, active predators, passive filter... |
| Tipo: Text |
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| Ano: 2009 |
URL: https://archimer.ifremer.fr/doc/00212/32332/30784.pdf |
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| Lagaria, A.; Psarra, S.; Lefevre, D.; Van Wambeke, France; Courties, C.; Pujo-pay, M.; Oriol, L.; Tanaka, T.; Christaki, U.. |
| We examined the effects of nutrient additions on rates of (14)C-based particulate and dissolved primary production as well as O(2)-based metabolic rates in surface waters (8 m) of three anticyclonic eddies, located in the Western, Central and Eastern Mediterranean. Ship-board microcosm experiments employing additions of inorganic nitrogen (+N) and phosphorus (+P), alone and in combination (+NP), were conducted in June/July 2008 during the BOUM (Biogeochemistry from the Oligotrophic to the Ultra-oligotrophic Mediterranean) cruise. In all three experiments, particulate primary production was significantly stimulated by the additions of nitrogen (+N, +NP) while no effect was observed with the addition of phosphorus alone (+P). Percent extracellular release of... |
| Tipo: Text |
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| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00133/24401/22418.pdf |
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| Registros recuperados: 12 | |
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