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| Registros recuperados: 220 | |
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| Marchetti, Julie; Bougaran, Gael; Jauffrais, Thierry; Lefebvre, Sebastien; Rouxel, Catherine; Saint-jean, Bruno; Lukomska, Ewa; Robert, Rene; Cadoret, Jean-paul. |
| In aquaculture, particularly in bivalve hatcheries, the biochemical composition of algal diets has a strong influence on larval and post-larval development. Biochemical composition is known to be related to culture conditions, among which light represents a major source of variation. The effects of blue light on biochemical composition and photosynthetic rate of Isochrysis sp. (T-iso) CCAP 927/14 were assessed in chemostat at a single irradiance (300 μmol photons m−2 s−1) and compared with white light. Two different dilution (renewal) rates were also tested: 0.7 and 0.2 d−1. Relative carbohydrate content was lower under blue light than under white light at both dilution rates, whereas chlorophyll a and photosynthesis activity were higher. In contrast,... |
| Tipo: Text |
Palavras-chave: Isochrysis; Blue light; Photosynthesis; Proximate composition; Chemostat. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00085/19599/17237.pdf |
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| Marcelino, Vanessa R.; Cremen, Ma Chiela M.; Jackson, Chistopher J.; Larkum, Anthony A. W.; Verbruggen, Heroen. |
| Some photosynthetic organisms live in extremely low light environments. Light limitation is associated with selective forces as well as reduced exposure to mutagens, and over evolutionary timescales it can leave a footprint on species' genomes. Here, we present the chloroplast genomes of four green algae (Bryopsidales, Ulvophyceae), including the endolithic (limestone-boring) alga Ostreobium quekettii, which is a low light specialist. We use phylogenetic models and comparative genomic tools to investigate whether the chloroplast genome of Ostreobium corresponds to our expectations of how low light would affect genome evolution. Ostreobium has the smallest and most gene-dense chloroplast genome among Ulvophyceae reported to date, matching our expectation... |
| Tipo: Text |
Palavras-chave: Genome streamlining; Photosynthesis; Rates of evolution; Boring algae; Stoichiogenomics. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00659/77094/78418.pdf |
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| Demory, David; Combe, Charlotte; Hartmann, Philipp; Talec, Amelle; Pruvost, Eric; Hamouda, Raouf; Souille, Fabien; Lamarea, Pierre-olivier; Bristeau, Marie-odile; Sainte-marie, Jacques; Rabouille, Sophie; Mairet, Francis; Sciandra, Antoine; Bernard, Olivier. |
| Hydrodynamics in a high-rate production reactor for microalgae cultivation affects the light history perceived by cells. The interplay between cell movement and medium turbidity leads to a complex light pattern, whose forcing effects on photosynthesis and photoacclimation dynamics are nontrivial. Hydrodynamics of high density algal ponds mixed by a paddle wheel has been studied recently, although the focus has never been on describing its impact on photosynthetic growth efficiency. In this multidisciplinary downscaling study, we first reconstructed single cell trajectories in an open raceway using an original hydrodynamical model offering a powerful discretization of the Navier-Stokes equations tailored to systems with free surfaces. The trajectory of a... |
| Tipo: Text |
Palavras-chave: Photosynthesis; Hydrodynamics; Modelling; Photoacclimation; Dunaliella salina; Non-photochemical quenching. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00445/55692/57352.pdf |
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| Plus, Martin; Auby, Isabelle; Verlaque, Marc; Levavasseur, Guy. |
| The main photosynthesis and respiration parameters (dark respiration rate, light saturated production rate, saturation irradiance, photosynthetic efficiency) were measured on a total of 23 macrophytes of the Than lagoon (2 Phanerogams, 5 Chlorophyceae, 10 Rhodophyceae and 6 Phaeophyceae). Those measurements were performed in vitro under controlled conditions, close to the natural ones, and at several seasons. Concomitantly, measurements of pigment concentrations, carbon, phosphorous and nitrogen contents in tissues were performed. Seasonal intra-specific variability of photosynthetic parameters was found very high, enlightening an important acclimatation capacity. The highest photosynthetic capacities were found for Chlorophyceae (e.g. Monostroma obscurum... |
| Tipo: Text |
Palavras-chave: Thau lagoon; Phaeophyceae; Rhodophyceae; Chlorophyceae; Seagrasses; Seasonal variations; Oxygen method; Macrophytes; Light response curve; Photosynthesis. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-465.pdf |
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| Merceron, Michel; Antoine, Virginie; Auby, Isabelle; Morand, P. |
| Ulva spp., the algae most responsible for green tides in Brittany (France), are found on the foreshore and in the most beachward wave area (MBWA) of many bays during green tide phenomena. These algae have recently been seen drifting at greater depths (reaching -20 m). In view of the significant quantities of algae found at these depths, and the less favorable conditions for algal growth than in the intertidal zone, we attempted to determine if they could grow there. For that, during their maximum growth period (from May to July), algae were picked up at three stations located on the foreshore, in the MBWA and in the subtidal (deep) zones of the Bay of Douarnenez, and their nitrogen, carbon and chlorophyll a+b contents were determined, and their... |
| Tipo: Text |
Palavras-chave: Nutrients; Irradiance; Photosynthesis; Ulva sp.; Algal blooms; Eutrophication. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3527.pdf |
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| Lacour, Thomas; Lariviere, Jade; Ferland, Joannie; Bruyant, Flavienne; Lavaud, Johann; Babin, Marcel. |
| Thalassiosira gravida is a major Arctic diatom responsible for the under-ice spring bloom. We investigated T. gravida physiological plasticity growing it at two temperatures (0 and 5°C) and under different light intensities typically found in its natural environment. T. gravida showed remarkable thermal- and photo-acclimatory plasticity including: low light saturation parameter for growth (KE) and photosynthesis (EK), low μmax but relatively high Chl a/C, low C/N, and decreasing light-saturated carbon fixation rate (PmC) with increasing growth irradiance. T. gravida also showed remarkable photoprotective features, namely a strong sustained non-photochemical quenching (NPQs, hour kinetics relaxation) supported by a high amount of xanthophyll cycle pigments.... |
| Tipo: Text |
Palavras-chave: Arctic diatom; Photosynthesis; Sustained NPQ; Irradiance; Temperature. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00462/57387/59468.pdf |
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| Caumette, P. |
| In the deepest parts of the estuarine region of Ebrie Lagoon (Abidjan Africa, (5 degree N, 4 degree W) stratified conditions have been observed during the rainy season (May to Nov.), owing to salinity differences between oxic and anoxic layers. At the interface, 3-4 m depth, phototrophic bacteria (Chromatium, Chlorobium and Pelodictyon ) developed, forming a brown layer due to their different pigments. Their production has been estimated at 41% of the total photosynthetic production during high stratification (Sep. 1981) and their biomass was used by the copepod population for 40 to 60% of its diet. During the dry season, the water column became homogeneous and oxygen was detected to 6m depth. The brown layer of phototrophic bacteria disappeared, as well... |
| Tipo: Text |
Palavras-chave: Chlorobium; Chromatium; Primary production; Photosynthesis; Estuaries; Seasonal variations; Plankton; Stratification; Vertical distribution; Bacteria; Coastal lagoons; Trophic relationships; Biomass. |
| Ano: 1984 |
URL: http://archimer.ifremer.fr/doc/1984/acte-957.pdf |
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| Verryckt, Lore T.; Van Langenhove, Leandro; Ciais, Philippe; Courtois, Elodie A.; Vicca, Sara; Peñuelas, Josep; Stahl, Clément; Coste, Sabrina; Ellsworth, David S.; Posada, Juan M.; Obersteiner, Michael; Chave, Jérôme; Janssens, Ivan A.. |
| Measuring leaf gas exchange from canopy leaves is fundamental for our understanding of photosynthesis and for a realistic representation of carbon uptake in vegetation models. Since canopy leaves are often difficult to reach, especially in tropical forests with emergent trees up to 60 m at remote places, canopy access techniques such as canopy cranes or towers have facilitated photosynthetic measurements. These structures are expensive and therefore not very common. As an alternative, branches are often cut to enable leaf gas exchange measurements. The effect of branch excision on leaf gas exchange rates should be minimized and quantified to evaluate possible bias. We compared light‐saturated leaf net photosynthetic rates measured on excised and intact... |
| Tipo: Text |
Palavras-chave: Branch cutting; Canopy physiology; French Guiana; Gas exchange; Photosynthesis; Rainforest; Stomatal conductance. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00613/72466/71949.pdf |
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| Bougaran, Gael; Le Dean, Loic; Lukomska, Ewa; Kaas, Raymond; Baron, Regis. |
| Starting microalgae continuous culture generally includes a preliminary batch culture to obtain sufficient cell density. It is possible to apply continuous regime from the beginning of the culture (IC mode) rather than to begin by an initial batch (IB mode). It is our purpose to check that both initial modes lead to identical steady-state cell characteristics. The microalga Isochrysis galbana affinis Tahiti was used for this comparative study. With an initial cell density of 5 x 10(5) cell ml(-1) and a dilution rate of about 1.0 d(-1), both IB and IC modes led to identical cell density once steady-state is reached between 6 and 8 d after inoculation in the two cases. Cell concentration of chlorophyll a and pheopigment a were found to be similar for IB and... |
| Tipo: Text |
Palavras-chave: Isochrysis; Cell quota; Photosynthesis; Steady state; Continuous culture. |
| Ano: 2003 |
URL: http://archimer.ifremer.fr/doc/2003/publication-597.pdf |
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| Couet, Douglas; Pringault, Olivier; Bancon-montigny, Chrystelle; Briant, Nicolas; Poulichet, Francoise Elbaz; Delpoux, Sophie; Yahia, Ons Kefi-daly; Hela, Bengharbia; Charaf, M'Rabet; Herve, Fabienne; Rovillon, Georges-augustin; Amzil, Zouher; Laabir, Mohamed. |
| Controlled laboratory experiments were conducted to test the effects of copper (Cu2+) and butyltins (BuT) on the growth, photosynthetic activity and toxin content of two HABs (Harmful Algal Blooms) dinoflagellates, the planktonic Alexandrium catenella and the benthic Ostreopsis cf. ovata. Microalgae were exposed to increasing concentrations of Cu2+ (10−4 to 31 nM) or BuT (0.084 to 84 nM) for seven days. When considering the growth, EC50 values were 0.16 (±0.09) nM and 0.03 (±0.02) nM of Cu2+ for A. catenella and O. cf. ovata, respectively. Regarding BuT, EC50 was 14.2 (±6) nM for O. cf. ovata, while A. catenella growth inhibition appeared at BuT concentrations ≥27 nM. Photosynthetic activity of the studied dinoflagellates decreased with increasing Cu and... |
| Tipo: Text |
Palavras-chave: Alexandrium catenella; Ostreopsis cf. ovata; Cu; Butyltin; Photosynthesis; Toxins. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00418/52970/53896.pdf |
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| Heydarizadeh, Parisa; Boureba, Wafaa; Zahedi, Morteza; Huang, Bing; Moreau, Brigitte; Lukomska, Ewa; Couzinet-mossion, Aurelie; Wielgosz-collin, Gaetane; Martin-jezequel, Veronique; Bougaran, Gael; Marchand, Justine; Schoefs, Benoit. |
| In this study, we investigated the responses of Phaeodactylum tricornutum cells acclimated to 300 mu mol m(-2) s(-1) photon flux density to an increase (1000 mmol m(-2) s(-1)) or decrease (30 mmol m(-2)s(-1)) in photon flux densities. The light shift occurred abruptly after 5 days of growth and the acclimation to new conditions was followed during the next 6 days at the physiological and molecular levels. The molecular data reflect a rearrangement of carbon metabolism towards the production of phosphoenolpyruvic acid (PEP) and/or pyruvate. These intermediates were used differently by the cell as a function of the photon flux density: under low light, photosynthesis was depressed while respiration was increased. Under high light, lipids and proteins... |
| Tipo: Text |
Palavras-chave: Phaeodactylum tricornutum; Carbon metabolism; Light regulation; Photosynthesis; Chlorophyll fluorescence; Pyruvate hub. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00395/50620/52341.pdf |
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| Qui-minet, Zujaila Nohemy; Coudret, Jérôme; Davoult, Dominique; Grall, Jacques; Mendez‐sandin, Miguel; Cariou, Thierry; Martin, Sophie. |
| Made up of calcareous coralline algae, maerl beds play a major role as ecosystem engineers in coastal areas throughout the world. They undergo strong anthropogenic pressures, which may threaten their survival. The aim of this study was to gain insight into the future of maerl beds in the context of global and local changes. We examined the effects of rising temperatures (+3°C) and ocean acidification (−0.3 pH units) according to temperature and pH projections (i.e., the RCP 8.5 scenario), and nutrient (N and P) availability on three temperate maerl species (Lithothamnion corallioides, Phymatolithon calcareum, and Lithophyllum incrustans) in the laboratory in winter and summer conditions. Physiological rates of primary production, respiration, and... |
| Tipo: Text |
Palavras-chave: Calcification; Maerl; Nitrate; Ocean acidification; Ocean warming; Phosphate; Photosynthesis; Respiration. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00595/70722/68955.pdf |
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| Hourmant, Annick; Amara, Anis; Pouline, Patrick; Durand, Gael; Arzul, Genevieve; Quiniou, Francoise. |
| The herbicide bentazon (CASRN 25057-89-0) is extensively used in agriculture in Brittany (France) to replace atrazine. Bentazon is not readily adsorbed by soil and therefore it enters adjacent freshwater ecosystems, making its way to estuarine and marine waters areas. Information regarding its effects on marine ecosystems is scarce. Phytotoxicity assessments were conducted in the laboratory on the common diatom Chaetoceros gracilis using both the active ingredient and its formulated product (Basamais). The 3 day EC50 Using cell counts were, respectively, 150 mg/L and 60 mu g/L for bentazon active ingredient and for bentazon-formulated while cellular volume was increased. Although bentazon is known as a photosystem II inhibitor, it produced an increase of... |
| Tipo: Text |
Palavras-chave: Photosynthesis; Marine diatom; Growth; Chlorophylls; Chaetoceros gracilis; Carotenoids; Bentazon; ATP. |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6637.pdf |
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| Dupraz, Valentin; Ménard, Dominique; Akcha, Farida; Budzinski, Hélène; Stachowski-haberkorn, Sabine. |
| This study screened binary mixtures of pesticides for potential synergistic interaction effects on growth of the marine microalgae Tisochrysis lutea and Skeletonema marinoi. It also examined the single and combined effects of three of the most toxic substances on microalgal physiology. Single substances were first tested on each microalgal species to determine their respective EC50 and concentration-response relationships. The toxicity of six and seven binary mixtures was then evaluated in microplate experiments on the growth of T. lutea and S. marinoi, respectively, using two mixture modelling approaches: isobolograms and the MIXTOX tool, based on Concentration Addition (CA) or Independent Action (IA) models. Significant cases of antagonism (for both... |
| Tipo: Text |
Palavras-chave: ROS; Photosynthesis; Lipids; Synergy; Isoproturon; Metazachlor. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00488/59928/63131.pdf |
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| Registros recuperados: 220 | |
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