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| Soulié, Tanguy; Mas, Sébastien; Parin, David; Vidussi, Francesca; Mostajir, Behzad. |
| Understanding how aquatic ecosystems respond to perturbations has emerged as a crucial way to predict the future of these ecosystems and to assess their capacity to produce oxygen and store atmospheric carbon. In this context, in situ mesocosm experiments are a useful approach for simulating disturbances and observing changes in planktonic communities over time and under controlled conditions. Within mesocosm experiments, the estimation of fundamental parameters such as gross primary production (GPP), net community production (NCP), and respiration (R) allows the evaluation of planktonic metabolic responses to a perturbation. The continuous estimation of these metabolic parameters in real time and at high frequency is made possible by employing noninvasive... |
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| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00686/79762/82562.pdf |
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| Vasseur, Christophe; Bougaran, Gael; Garnier, Matthieu; Hamelin, Jérôme; Leboulanger, Christophe; Le Chevanton, Myriam; Mostajir, Behzad; Sialve, Bruno; Steyer, Jean-philippe; Fouilland, Eric. |
| Association of microalgae culture and anaerobic digestion seems a promising technology for sustainable algal biomass and biogas production. The use of digestates for sustaining the growth of microalgae reduces the costs and the environmental impacts associated with the substantial algal nutrient requirements. A natural marine algae–bacteria consortium was selected by growing on a medium containing macro nutrients (ammonia, phosphate and acetate) specific of a digestate, and was submitted to a factorial experimental design with different levels of temperature, light and pH. The microalgal consortium reached a maximum C conversion efficiency (i.e. ratio between carbon content produced and carbon supplied through light photosynthetic C conversion and acetate)... |
| Tipo: Text |
Palavras-chave: Optimization; Nannochloris; Heterotrophic bacteria; Anaerobic digestion; Bioenergy. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00085/19642/17419.pdf |
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| Richard, Marion; Bec, Beatrice; Vanhuysse, Charles; Mas, Sébastien; Parin, David; Chantalat, Camila; Le Gall, Patrik; Fiandrino, Annie; Lagarde, Franck; Mortreux, Serge; Ouisse, Vincent; Rolland, Jean-luc; Degut, Anaïs; Hatey, Elise; Fortune, Martine; Roque D'Orbcastel, Emmanuelle; Messiaen, Gregory; Munaron, Dominique; Callier, Myriam; Oheix, Jocelyne; Derolez, Valerie; Mostajir, Behzad. |
| Oysters modify the planktonic microbial community structure by their filtration and NH4 excretion activities. While many studies have been conducted on this subject with adult oysters, none had been carried out in situ with juveniles. Pacific oyster juveniles (Magallana gigas, previously Crassostrea gigas) died massively all over the world since 2008 in relation with OsHV-1 infection. During mortality episodes, sick and dead oysters are not separated from healthy live ones, and left to decay in the surrounding environment, with unknown consequences for the nutrient cycle and planktonic microbial components (PMC). The present study aimed to elucidate for the first time the interactions between oyster juveniles and PMC during a mortality episode. Innovative... |
| Tipo: Text |
Palavras-chave: Magallana gigas; Crassostrea gigas; Spat; OsHV-1 mu Var; Mortality; Picoplankton; Heterotrophic flagellates; Ciliates; Uronema; Balanion. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00474/58559/61115.pdf |
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| Courboulès, Justine; Vidussi, Francesca; Soulié, Tanguy; Mas, Sébastien; Pecqueur, David; Mostajir, Behzad. |
| To investigate the responses of a natural microbial plankton community of coastal Mediterranean waters to warming, which are still poorly known, an in situ mesocosm experiment was carried out in Thau Lagoon during autumn 2018. Several microorganisms, including virio-, bacterio-, and phytoplankton < 10 µm in size, were monitored daily and analysed using flow cytometry for 19 consecutive days in six mesocosms. Three mesocosms (control) had the same natural water temperature as the lagoon, and the other three were warmed by + 3 °C in relation to the control temperature. The cytometric analyses revealed an unexpected community dominated by picophytoplanktonic cells, including Prochlorococcus-like and Picochlorum-like cells, which had not previously been... |
| Tipo: Text |
Palavras-chave: Pico- and nanophytoplankton; Bacterioplankton; Virus; Warming; In situ mesocosm; Thau lagoon. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00688/79979/82933.pdf |
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| Mostajir, Behzad; Roques, Cecile; Bouvier, Corinne; Bouvier, Thierry; Fouilland, Eric; Got, Patrice; Le Floc'H, Emilie; Nouguier, Jean; Mas, Sebastien; Sempere, Richard; Sime-ngando, Telesphore; Troussellier, Marc; Vidussi, Francesca. |
| The impact of fish and oysters on components of the pelagic microbial food web (MFW) was studied in a 10 d mesocosm experiment using Mediterranean coastal waters. Two mesocosms contained natural water only ('Controls'), 2 contained natural water with Crassostrea gigas ('Oyster'), and 2 contained natural water with Atherina spp. ('Fish'). Abundances and biomasses of microorganisms (viruses, bacteria, phytoplankton, heterotrophic flagellates, and ciliates) were measured to estimate their contribution to the total microbial carbon biomass. Two MFW indices, the microbial autotroph: heterotroph C biomass ratio (A:H) structural index and the gross primary production: respiration ratio (GPP:R) functional index, were defined. In the Fish mesocosms, selective... |
| Tipo: Text |
Palavras-chave: Microbial food web; Virioplankton; Bacterioplankton; Phytoplankton; Protozooplankton; Crassostrea; Atherina; Autotrophy; Heterotrophy. |
| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00284/39489/73675.pdf |
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| Charria, Guillaume; Schmitt, François; Artigas, Felipe; Berthebaud, Eric; Bonnat, Armel; Bourrin, François; Bozec, Yann; Cariou, Thierry; Claquin, Pascal; Conan, Pascal; Coppola, Laurent; Delalée, Franck; Facq, Jean-valery; Farcy, Patrick; Ferreira, Sophie; Garcia, Fabrice; Grisoni, Jean-michel; Jacqueline, Franck; Jacquet, Matthias; Lefebvre, Alain; Leredde, Yann; Le Roux, Jean-francois; Mas, Sébastien; Mostajir, Behzad; Mousseau, Laure; Pairaud, Ivane; Petton, Sebastien; Pouvreau, Stephane; Quemener, Loic; Ravel, Christophe; Raimbault, Patrick; Repecaud, Michel; Retho, Michael; Rimmelin-maury, Peggy; Riou, Philippe; Savoye, Nicolas; Souchu, Philippe; Verney, Romaric; Vuillemin, Renaud. |
| COAST-HF (Coastal OceAn observing SysTem – High Frequency) is a French national observation network of the physical and biogeochemical dynamics of the coastal ocean, at high frequency. COAST-HF aims at understanding and analysing changes of contrasted coastal ecosystems at different temporal scales from extreme or intermittent high frequency (hour, day) events to multi-year trends. Since several years (from 2000 for the longest time series in Bay of Brest), the network extends along the English Channel, Atlantic and Mediterranean French coasts through 14 fixed platforms instrumented for the in situ high-frequency (≤ 1h) observations. Several French research institutes (IFREMER, CNRS, Marine Universities) are operating these systems. The organization of... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00635/74723/74708.pdf |
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| Alves-de-souza, Catharina; Pecqueur, David; Le Floc'H, Emilie; Mas, Sebastien; Roques, Cecile; Mostajir, Behzad; Vidussi, Franscesca; Velo-suarez, Lourdes; Sourisseau, Marc; Fouilland, Eric; Guillou, Laure. |
| Dinoflagellate blooms are frequently observed under temporary eutrophication of coastal waters after heavy rains. Growth of these opportunistic microalgae is believed to be promoted by sudden input of nutrients and the absence or inefficiency of their natural enemies, such as grazers and parasites. Here, numerical simulations indicate that increasing nutrient availability not only promotes the formation of dinoflagellate blooms but can also stimulate their control by protozoan parasites. Moreover, high abundance of phytoplankton other than dinoflagellate hosts might have a significant dilution effect on the control of dinoflagellate blooms by parasites, either by resource competition with dinoflagellates (thus limiting the number of hosts available for... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00274/38478/36938.pdf |
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| Trombetta, Thomas; Vidussi, Francesca; Mas, Sébastien; Parin, David; Simier, Monique; Mostajir, Behzad. |
| Phytoplankton blooms are an important, widespread phenomenon in open oceans, coastal waters and freshwaters, supporting food webs and essential ecosystem services. Blooms are even more important in exploited coastal waters for maintaining high resource production. However, the environmental factors driving blooms in shallow productive coastal waters are still unclear, making it difficult to assess how environmental fluctuations influence bloom phenology and productivity. To gain insights into bloom phenology, Chl a fluorescence and meteorological and hydrological parameters were monitored at high-frequency (15 min) and nutrient concentrations and phytoplankton abundance and diversity, were monitored weekly in a typical Mediterranean shallow coastal system... |
| Tipo: Text |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00488/60004/63240.pdf |
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