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| Registros recuperados: 369 | |
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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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| Marie, Dominique; Rigaut-jalabert, Fabienne; Vaulot, Daniel. |
| Preservation of cells, choice of fixative, storage, and thawing conditions are recurrent issues for the analysis of phytoplankton by flow cytometry. We examined the effects of addition of the surfactant Pluronic F68 to glutaraldehyde-fixed photosynthetic organisms in cultures and natural samples. In particular, we examined cell losses and modifications of side scatter (a proxy of cell size) and fluorescence of natural pigments. We found that different marine phytoplankton species react differently to the action of Pluronic F68. In particular, photosynthetic prokaryotes are less sensitive than eukaryotes. Observed cell losses may result from cell lysis or from cell adhesion to the walls of plastic tubes that are commonly used for flow cytometry analysis.... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Flow cytometry; Preservation; Pluronic F68; Glutaraldehyde. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00374/48493/48858.pdf |
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| Videau, Christiane; Ryckaert, Mireille; L' Helguen, Stéphane. |
| Phytoplankton distribution and primary productivity were investigated in the Bay of Seine (eastern English Channel, France) in spring and early summer of 1992 and 1994. In 1992, the horizontal distribution of phytoplankton species was determined over the whole Bay of Seine. In 1994, species distribution and primary productivity were studied along the salinity gradient of the Seine plume and in the neighbouring marine waters. Phytoplankton distribution was characterised by the permanent diatom dominance from early spring to early summer. The spring bloom did not occur uniformly over the bay, but was initiated in the marine waters, in the middle of the bay and progressed towards the coast where it developed, in June, in the diluted waters of the Seine plume.... |
| Tipo: Text |
Palavras-chave: Bay of Seine; Primary productivity; Phytoplankton; Baie de Seine; Production primaire; Phytoplancton. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/1998/publication-843.pdf |
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| Dufour, P.; Cremoux, Jl.; Slepoukha, M.. |
| "In vitro" enrichment experiments on natural populations have been used to determine the nutrients controlling the potential biomass of phytoplancton in the Ebrié coastal lagoon. The limiting nutrients were generally nitrogen, phosphorus and carbon, in this order ; in three cases out of eleven, P and N act simultaneously ; in an extreme eutrophication case, N, P and C were all limiting. No effect was observed following addition of metals, vitamins or chelators. The limitations deduced from the enrichment experiments show a. good agreement with the elementary composition of the external medium ; in waters potentially limited by N alone, the dissolved inorganic nutrients have a N : P ratio lower than 25. The agreement is poorer when the sestonic N : P ratio... |
| Tipo: Text |
Palavras-chave: Lagune; Estuaire; Zone tropicale; Phytoplancton; Biomasse; Eléments limitants; Tests biologiques; Composition chimique; Coastal lagoon; Estuary tropical zone; Phytoplankton; Biomass; Limiting nutrients; Bioassay; Chemlcal composition. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/00306/41689/40898.pdf |
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| Basterretxea, G.; Font-munoz, Joan Salvador; Tuval, I. |
| Phytoplankton are by definition autotrophic microorganisms that passively drift with fluid motion. Accordingly, the traditional view of a turbulence-homogenized phytoplankton distribution in the ocean, where cells randomly organize and interact, is deeply rooted in biological oceanography studies. However, increasing understanding of microscopic processes in the ocean is revealing a world of microscale patterns resulting from cell behaviors and fluid-cell interactions that challenges this vision. Autotrophic cells have developed active (i.e., flagella) and passive (i.e., morphological structures and vesicles) motility mechanisms that allow them different degrees of spatial control. Their complex interaction with the ocean physicochemical landscape commonly... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Microscale; Turbulence; Orientation; Shear. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00621/73261/72476.pdf |
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| Morelle, Jérôme. |
| The estuaries play an important ecological role and are the site of many human activities because of their strategic position at the interface between continental and marine waters. Seine estuary is characteristic of large anthropized estuaries. Long-term management requires better knowledge of the spatial and temporal dynamics of the estuarine food webs. Phytoplankton and microphytobenthos are the main contributor of primary production (PP) in these ecosystems and are at the basis of trophic food webs. These compartments are often reduced to the chlorophyll concentration and their productivity has never been measured along the Seine estuary. The objective of this study was to estimate the PP of these compartments along the salinity gradient. In order to... |
| Tipo: Text |
Palavras-chave: PAM; ETR; 13C; TEP; EPS; Exopolymeric substances; Phytoplankton; Microphytobenthos; Transparent Exopolymeric Particles. |
| Ano: 2017 |
URL: https://archimer.ifremer.fr/doc/00498/60965/64373.pdf |
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| Merceron, Michel; Bentley, Daniel; Le Grand, Jacqueline; Lamort-datin, Laure; Kempf, Marc. |
| The environmental impact of a brown trout farm located in the Grande Rade de Cherbourg (Normandy) is reported. During observations the fish stock evolved within the range of 140 to 350 metric tons. Farm influence was researched on water column through hydrochemistry, phytoplankton, faecal bacteria and, on bottom, through grain size, organic matter, metals, macrobenthos. This report only deals with water column. Except ammonia, no hydrological parameter seems to be affected, even near to the net pens. Phytoplankton and coliform bacteria were not altered. An extra concentration of ammonia was detected at some tens meters from the raft, with favourable conditions. But generally it was impossible to observe it unless close to the farming structure, downward... |
| Tipo: Text |
Palavras-chave: Channel; Current; Faecal bacteria; Phytoplankton; Hydrology; Impact; Salmonid; Fish farm; Manche; Courant; Bactéries fécales; Phytoplancton; Hydrologie; Impact; Salmonidé; Aquaculture. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/1997/rapport-3342.pdf |
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| Rodier, M; Longo, S; Henry, K; Ung, A; Lo-yat, Alain; Darius, Ht; Viallon, J; Beker, B; Delesalle, B; Chinain, M. |
| Pearl farming lagoons are economically important, yet poorly studied ecosystems in French Polynesia. This paper describes a study conducted in 2016 in Takaroa (Tuamotu Archipelago), an atoll recurrently affected by harmful algal bloom (HAB) events. The objectives were to gain insight into phytoplankton community composition, identify the main bloom-forming species and investigate their potential for toxicity. A mesocosm approach was used to assess the response of phytoplankton communities to 3 nutrient treatments: Conway with Si, Si-depleted f/2 and a commercial N-P fertilizer. In total, 87 morpho-species were described from Takaroa lagoon, with dinoflagellates as the most diverse group. Diatoms (Extubocellulus sp., Cylindrotheca closterium, Nitzschia... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Taxonomy; Mesocosm; Bloom-forming species; Toxicity; French Polynesian lagoons. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00499/61059/64509.pdf |
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| Masson, Daniel; Piquet, Jean-come; Courtois, Olivier. |
| Billions of tons of ballast water are lreased world-wide every year. Living marine, brackish or freshwater organisms, including those noxioux or unwanted, can travel by that way from a part of the world to another. A successful introduction needs : 1) survival during the pumping process 2) survival in ships' ballasts 3) survival and repreoduction in the new environment. To assess the survival conditions in ship's ballasts, a small scale pilot system has been built (MARTOB project), more realistic than laboratory vials and easier to handle than a real ballast. Bacteria and phytoflagellates coming from ship's sampling or from cultures were introduced in the system ; their survival in several waters or sediments are studied, a useful method to assess the... |
| Tipo: Text |
Palavras-chave: Ballast water; Bacteria; Phytoplankton. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/00074/18535/16079.pdf |
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| Maar, Marie; Butenschon, Momme; Daewel, Ute; Eggert, Anja; Fan, Wei; Hjollo, Solfrid S.; Hufnagl, Marc; Huret, Martin; Ji, Rubao; Lacroix, Genevieve; Peck, Myron A.; Radtke, Hagen; Sailley, Sevrine; Sinerchia, Matteo; Skogen, Morten D.; Travers-trolet, Morgane; Troost, Tineke A.; Van De Wolfshaar, Karen. |
| The present study describes the responses of summer phytoplankton biomass to changes in top-down forcing (expressed as zooplankton mortality) in three ecosystems (the North Sea, the Baltic Sea and the Nordic Seas) across different 3D ecosystem models. In each of the model set-ups, we applied the same changes in the magnitude of mortality (±20%) of the highest trophic zooplankton level (Z1). Model results showed overall dampened responses of phytoplankton relative to Z1 biomass. Phytoplankton responses varied depending on the food web structure and trophic coupling represented in the models. Hence, a priori model assumptions were found to influence cascades and pathways in model estimates and, thus, become highly relevant when examining ecosystem pressures... |
| Tipo: Text |
Palavras-chave: Plankton functional types; Trophic cascades; Zooplankton mortality; Phytoplankton; Ensemble modelling. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00433/54466/56083.pdf |
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| Labry, Claire; Delmas, Daniel; Moriceau, Brivaela; Gallinari, Morgane; Quere, Julien; Youenou, Agnes. |
| Phosphorus (P) limitation of phytoplankton growth is known to affect the accumulation and release of carbohydrates (CHO) by micro-algae. However, relatively little is known about the fate of algal exudates, notably their bacterial degradation. The CHO chemical characterization is also not exhaustive, especially in ‘functional’ pools relevant for phytoplankton physiology (particulate reserve [R] or structural [S] CHO) and for bacterial degradation (dissolved mono- [MDCHO] and polysaccharides [P-DCHO]). In this study, we investigated how P depletion and repletion affect the CHO composition in diatom Thalassiosira weissflogii cultures, and the shortterm response of free and diatom-attached bacteria in terms of abundance and potential βglucosidase activity... |
| Tipo: Text |
Palavras-chave: P limitation; Phytoplankton; Diatom; Bacteria; Mineralization; Carbohydrate; Glucosidase. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00628/74045/73532.pdf |
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| Maestrini, Serge; Balode, Maija; Bechemin, Christian; Purina, Ingrida. |
| To investigate whether uptake of dissolved organic compounds might favour the growth potential of toxic cyanobacteria and dinoflagellates, surface water was collected in late July 1997 in the Gulf of Riga, and enriched with different nitrogen sources. (1) Organic substances were added (25 mu M N) under P-, Si- and Fe-replete conditions. Urea sustained a biomass increase (protein content) 20% greater than that with NH sub(4) super(+). Glycine, hypoxanthine and putrescine gave only 50% of the biomass obtained with NH sub(4) super(+). Glutamic acid and spermine supported growth in only one case each, and guanine in none. (2) The >1000 dalton fraction of dissolved organic matter (DOM) taken from the Daugava River was provided at concentrations of 5, 15 and... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Terrigenous DON; Nitrogenous nutrients; Baltic Sea. |
| Ano: 1999 |
URL: http://archimer.ifremer.fr/doc/00173/28437/26769.pdf |
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| Robert, Rene; Chretiennot-dinet, Marie-josèphe; Kaas, Raymond; Martin-jezequel, Véronique; Moal, Jeanne; Le Coz, Jean-rene; Nicolas, Jean-louis; Bernard, Eudes; Connan, Jean-paul; Le Dean, Loic; Le Gourrierec, Gaetane; Leroy, Bertrand; Quere, Claudie. |
| in mollusc hatcheries. Consequently, we assessed themost commonly used species to establish their growth and size profiles, their cytomorphological, biochemical, biomolecular identification as well as their cytometer signs, and also their ability to grow under extreme conditions of temperature and salinity. This work aimed at matching the conformity of the strains used in Argenton (dispatched to most of the French commercial hatcheries) to those of a referenced culture collection. A previous screening preceded this study, because of the 45 species and/or clones held originally, Argenton kept no more than 15 species. As most of the latter are also represented in referenced collection, our strains are therefore correctly identified. On the other hand, the... |
| Tipo: Text |
Palavras-chave: Ecological limits; Biomolecular profile; Flow cytometry; Biochemical composition; Cytomorphology; Phytoplankton; Mollusc; Hatchery; Ecotolérance; Profil biomoléculaire; Cytométrie en flux; Composition biochimique; Cytomorphologie; Phytoplancton; Mollusques; Ecloserie. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/2004/rapport-1546.pdf |
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| Michel, Pierre; Boutier, Bernard; Herbland, Alain; Averty, Bernard; Artigas, Lf; Auger, Dominique; Chartier, E. |
| The arsenic (As) cycle in the marine environment is known to be sensitive to biological activity. Within the scope of the National Coastal Oceanography Program, we undertook a specific study of the behaviour of this element in a water column on the continental shelf of the Bay of Biscay off the Gironde estuary during two oceanographic cruises conducted in May 1994 and May 1995. Various chemical forms were measured: arsenite (As3), at-senate (As5), monomethylarsenic (MMA), dimethylarsenic (DMA) and dissolved total As after ultraviolet mineralization. The net flux of total As from the Gironde estuary was evaluated as well as its effect on the concentration in surface marine waters. The vertical profiles in the coastal zone during a period of active primary... |
| Tipo: Text |
Palavras-chave: Arsenic; Phytoplankton; Speciation; Gironde plume; Biscay Bay. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/1998/publication-851.pdf |
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| Registros recuperados: 369 | |
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