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| Registros recuperados: 369 | |
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| Labry, Claire; Herbland, Alain; Delmas, Daniel. |
| More and more studies emphasize the status of phosphorus (P) as the principal limiting nutrient of phytoplankton growth, especially in coastal waters under the influence of freshwater discharges. The purpose of the present paper is to investigate the role of P on planktonic production in the waters influenced by the Gironde discharges; the Gironde being one of the two largest rivers on the French Atlantic coast. The survey is based on several cruises made in 1998 and 1999. Two different patterns were observed for waters with salinity below and above 34.5. For waters with salinity <34.5. P was found to be the first limiting nutrient of winter and spring phytoplankton blooms, based on undetectable phosphate (<20 nM), high NO3 : PO4 ratios, typically... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; River plume; Salinity; Water quality analysis; Phytoplankton; Planktonic production. |
| Ano: 2002 |
URL: http://archimer.ifremer.fr/doc/2002/publication-690.pdf |
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| Trommer, Gabriele; Leynaert, Aude; Klein, Cecile; Naegelen, Aurore; Beker, Beatriz. |
| Phytoplankton nutrient limitation patterns were investigated in an anthropogenically influenced coastal ecosystem with a high nutrient load. Weekly nutrient limitation bioassays, and water chemistry and stoichiometry measurements were performed in the Bay of Brest, France, from February to July 2011. Each limitation bioassay included phosphorus, nitrogen, silicate and all possible combined nutrient additions, and lasted over 72 h. Results showed that the phytoplankton community experienced a general P limitation from March to July. N limitation alone was observed only during 1 week in early March. Subsequently, all limitation bioassays revealed primary P limitation, indicated by significantly increased growth rates in all samples containing P additions.... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Stoichiometry; Bioassays; Nutrient limitation; Coastal ecosystem. |
| Ano: 2013 |
URL: https://archimer.ifremer.fr/doc/00368/47947/48023.pdf |
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| Tiano, Marion; Tronczynski, Jacek; Harmelin-vivien, Mireille; Tixier, Celine; Carlotti, Francois. |
| PCB levels in plankton were investigated in the Bay of Marseille, Western Mediterranean Sea, between September 2010 and October 2011. Concentrations of PCB congeners (CB 18, CB 52, CB 101, CB 118, CB 138, CB 153, CB 180) were determined in three plankton size-classes (60–200, 200–500 and 500–1000 μm) together with different parameters: chlorophyll content, plankton dry-weight biomass, carbon and nitrogen stable isotope ratios and plankton-community structure. The ∑PCB7 concentrations ranged between 14.2 and 88.1 ng g−1 d.w., for all size classes and all sampling periods. The results do not show the biomass dilution effect and indicate moderate but significant biomagnification with plankton trophic position estimated by δ15N signatures. Equilibrium with... |
| Tipo: Text |
Palavras-chave: PCBs; Phytoplankton; Zooplankton; Bioaccumulation; Coastal; Bay of Marseille. |
| Ano: 2014 |
URL: https://archimer.ifremer.fr/doc/00218/32881/31371.pdf |
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| Mihnea, Pe. |
| Between 1980 and 1994, thirteen marine transects off the Romanian coast were sampled at monthly intervals from February to October at 5, 10 and 20 m depths, together with control sites situated 10, 20 and 30 miles from the coast. The present paper is based on 2,864 phytoplankton and 1,588 pigment samples. In this long data set, consistent patterns of phytoplanktonic community structure were identified: 1) The community maintained the capacity to produce huge biomasses (max. 20,163-205,084 or even 422,140 x 10(3) cell l(-1)), but an increased tendency to develop in ''patches'' became much more evident; 2) The frequency and cell density of nannoplanktonic species increased up to bloom phenomena: Apedinella (21.5), Mantoniella (5.97), Hyalobrion (13.25), and... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Nano-ultraplankton; Chryso-cryptophyta. |
| Ano: 1997 |
URL: http://archimer.ifremer.fr/doc/00093/20385/18052.pdf |
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| Bec, Béatrice; Husseini Ratrema, Julie; Collos, Yves; Souchu, Philippe; Vaquer, André. |
| The dynamics of the phytoplankton community were investigated in a marine coastal lagoon (Thau, NW Mediterranean) from February 1999 to January 2000. Dilution experiments, chlorophyll a (Chl a) size-fractionation and primary production measurements were conducted monthly. Maximum growth and microzooplankton grazing rates were estimated from Chl a biomass fractions to separate pico- from nano- and microphytoplankton and by flow cytometry to distinguish between picoeukaryotes and picocyanobacteria. In spring, the phytoplankton community was dominated by Chaetoceros sp. and Skeletonema costatum, which represented most of biomass (B) and primary production (P). Nano- and microphytoplankton growth was controlled by nutrient availability and exceeded losses due... |
| Tipo: Text |
Palavras-chave: Coastal lagoon; NW Mediterranean; Picoeukaryote; Phytoplankton. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-726.pdf |
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| Grant, J; Bacher, Cedric; Cranford, P; Guyondet, T; Carreau, M. |
| A fully-coupled biological-physical-chemical model of a coastal ecosystem was constructed to examine the impact of suspended mussel culture on phytoplankton biomass in Tracadie Bay, Prince Edward Island, Canada. Due to the extent of mussel culture there, we hypothesised that shellfish filtration would control the concentration and distribution of phytoplankton and other suspended particles in the bay. Circulation was delineated with a tidally-driven 2D numerical model and used to drive an ecosystem model with a focus on pelagic components including phytoplankton production, nutrients, detritus, and mussels. The benthos were treated as a sink. Nutrients and seston were forced by tidal exchange and river input, with phytoplankton additionally forced by... |
| Tipo: Text |
Palavras-chave: Towed sensors; Nutrient dynamics; Circulation model; Phytoplankton; Carrying capacity; Shellfish aquaculture; Estuaries; Ecosystem model. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6951.pdf |
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| Condie, Scott A.; Hayes, Donna; Fulton, Elizabeth A.; Savina, Marie. |
| The Clarence River Estuary is the largest estuary in southeast Australia, with an extensive floodplain encompassing multiple river channels and a large coastal lagoon. It is the focus of major commercial and recreational fisheries and there is pressure to divert its freshwater inputs for agricultural and domestic uses. We used a spatial biogeochemical model to simulate the variability and evolution of this system on timescales from days to decades over the past half century. Like most tropical and subtropical estuaries, the Clarence River Estuary is strongly influenced by river discharge, sediment and nutrient loads. Given the high nutrient loads arriving from the upper catchment, plankton biomasses in the model were typically limited by flushing through... |
| Tipo: Text |
Palavras-chave: Coastal lagoon; Flushing; Land-use; Climate impacts; Nutrients; Phytoplankton; Zooplankton. |
| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00175/28673/27113.pdf |
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| Guillaud, Jean-francois; Aminot, Alain; Delmas, Daniel; Gohin, Francis; Lunven, Michel; Labry, Claire; Herbland, Alain. |
| Seasonal variations in nutrient inputs are described for the main rivers (Loire and Vilaine) flowing into the northern Bay of Biscay. The river plumes are high in N/P ratio in late winter and spring, but not in the inner plume during the summer. Conservative behavior results in most nutrients entering the estuary and eventually reaching the coastal zone. Temporal and spatial aspects of phytoplankton growth and nutrient uptake in the northern Bay of Biscay distinguish the central area of salinity 34 from the plume area. The first diatom bloom appears offshore in late winter, at the edge of the river plumes, taking advantage of haline stratification and anticyclonic "weather windows." In spring, when the central area of the northern shelf is... |
| Tipo: Text |
Palavras-chave: Northern Bay of Biscay; Phytoplankton; Continental shelf; Riverine inputs; Nutrients. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2007/publication-2354.pdf |
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| Abikhalil, Celina; Finkelstein, Darren S.; Conejero, Genevieve; Du Bois, Justin; Destoumieux-garzon, Delphine; Rolland, Jean-luc. |
| Exposure of the toxin-producing dinoflagellate Alexandrium catenella (A. catenella) was previously demonstrated to cause apoptosis of hemocytes in the oyster species Crassostrea gigas. In this work, a coumarin-labeled saxitoxin appeared to spread throughout the cytoplasm of the hemocytes. PSTs, including saxitoxin, were also shown to be directly responsible for inducing apoptosis in hemocytes, a process dependent on caspase activation and independent of reactive oxygen species (ROS) production. A series of in vitro labeling and microscopy experiments revealed that STX and analogs there of induced nuclear condensation, phosphatidylserine exposure, membrane permeability, and DNA fragmentation of hemocytes. Unlike in vertebrates, gonyautoxin-5 (GTX5), which... |
| Tipo: Text |
Palavras-chave: Shellfish; Toxin; Harmful algae; Phytoplankton. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00391/50272/50905.pdf |
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| Juin, Camille; Bonnet, Antoine; Nicolau, Elodie; Berard, Jean-baptiste; Devillers, Romain; Thiery, Valerie; Cadoret, Jean-paul; Picot, Laurent. |
| A fast and high-resolution UPLC-MSE analysis was used to identify phytoplankton pigments in an ethanol extract of Porphyridium purpureum (Pp) devoid of phycobiliproteins. In a first step, 22 standard pigments were analyzed by UPLC-MSE to build a database including retention time and accurate masses of parent and fragment ions. Using this database, seven pigments or derivatives previously reported in Pp were unequivocally identified: beta,beta-carotene, chlorophyll a, zeaxanthin, chlorophyllide a, pheophorbide a, pheophytin a, and cryptoxanthin. Minor amounts of Divinyl chlorophyll a, a chemotaxonomic pigment marker for prochlorophytes, were also unequivocally identified using the database. Additional analysis of ionization and fragmentation patterns... |
| Tipo: Text |
Palavras-chave: Carotenoid; Chlorophyll; Dereplication; Divinyl chlorophyll a; Galactosyldiacylglycerol; Gracilamide; Mass spectrometry; MSE; Phytoplankton; Pigment; Porphyridium purpureum; UPLC. |
| Ano: 2015 |
URL: http://archimer.ifremer.fr/doc/00269/37994/36069.pdf |
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| Ory, Pascaline; Palesse, S.; Delmas, Daniel; Montanie, Helene. |
| The abundance and composition of microbial communities were investigated during 2007 in Marennes Oleron Bay (France) in order to characterize the biological relationships governing the planktonic food web. Compared to the results of previous years, there was a lower abundance and a lower magnitude of variations in autotrophic and heterotrophic microbial entities in 2007. Using a Spearman rank correlation analysis, a significant link for biological abundance was only noted between bacteria and ciliates. However, an interesting relationship was highlighted between chlorophyll a and bacterial aminopeptidase and beta-glucosidase exoenzymatic activities. Two characteristic periods of virus-bacteria uncoupling were observed in spring and autumn 2007. Using... |
| Tipo: Text |
Palavras-chave: Virus; Bacteria; Phytoplankton; Diversity; Aminopeptidase. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00050/16099/13571.pdf |
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| Druon, Jean-noel; Loyer, S; Gohin, Francis. |
| Different scales of hydrological and biological patterns of the Bay of Biscay are assessed using space-borne and airborne optical remote sensing data, field measurements and a 3-dimensional biophysical model. If field measurements provide accurate values on the vertical dimension, ocean colour data offer frequent observations of surface biological patterns at various scales of major importance for the validation of ecosystem modelling. Although the hydrobiological model of the continental margin reproduces the main seasonal variability of surface biomass, the optical remote sensing data have helped to identify low grid resolution, input inaccuracies and neglect of swell-induced erosion mechanism as model limitations in shallow waters. Airborne remote... |
| Tipo: Text |
Palavras-chave: Bay of Biscay; Models; Scaling; Remote sensing; Satellite observation; Phytoplankton. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-953.pdf |
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| Morelle, Jerome; Schapira, Mathilde; Claquin, Pascal. |
| Exopolysaccharides (EPS) play an important role in the carbon flux and may be directly linked to phytoplankton and microphytobenthos production, most notably in estuarine systems. However the temporal and spatial dynamics of estuarine EPS are still not well understood, nor how primary productivity triggers this variability at these different scales. The aim of this study was to investigate the primary productivity of phytoplankton and EPS dynamics in the Seine estuary over a tidal cycle in three different haline zones over two contrasted seasons. The other objectives was to investigate the origin of pools of soluble carbohydrates (S-EPS) and transparent exopolymeric particles (TEP) in phytoplankton, microphytobenthos or other compartments. High frequency... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Microphytobenthos; PAM fluorometer; Electron transport rate. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00400/51132/51898.pdf |
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| Bernard, O; Sciandra, A; Sallet, G. |
| New techniques - called software sensors - issued from the non-linear automatic control field and initially developed for non-linear chemical systems have been applied to a continuous culture of phytoplankton. A software sensor (or 'observer') combines an analytical differential equation based model and partial measurements of the system in order to estimate the non-measured state variables. It filters data and estimates the actual state of living systems, models of which are often rough approximations. The efficiency of this approach is illustrated with a nitrate-limited chemostat experiment with the chlorophyceae Dunaliella tertiolecta performed in a computer controlled fluctuating environment. (C) 2001 Ifremer/CNRS/IRD/Editions scientifiques et... |
| Tipo: Text |
Palavras-chave: Modèle de Droop; Systèmes non linéaires; Observateurs; Phytoplancton; Droop model; Non-linear systems; Observers; Phytoplankton. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/00322/43340/42888.pdf |
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| Leruste, A.; Malet, Nathalie; Munaron, Dominique; Derolez, Valerie; Hatey, E.; Collos, Y.; De Wit, R.; Bec, B.. |
| Along the French Mediterranean coast, a complex of eight lagoons underwent intensive eutrophication over four decades, mainly related to nutrient over-enrichment from continuous sewage discharges. The lagoon complex displayed a wide trophic gradient from mesotrophy to hypertrophy and primary production was dominated by phytoplankton communities. In 2005, the implementation of an 11 km offshore outfall system diverted the treated sewage effluents leading to a drastic reduction of anthropogenic inputs of nitrogen and phosphorus into the lagoons. Time series data have been examined from 2000 to 2013 for physical, chemical and biological (phytoplankton) variables of the water column during the summer period. Since 2006, total nitrogen and phosphorus... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Coastal lagoons; Nutrient; Sewage effluents; Re-oligotrophication. |
| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00346/45701/45324.pdf |
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| Tyrrell, T.; Merico, A.; Waniek, J. J.; Wong, C. S.; Metzl, N.; Whitney, F.. |
| We calculated correlations between seafloor depth and phytoplankton blooms in all three main high-nitrate, low-chlorophyll (HNLC) regions, but with a particular focus on the subarctic North Pacific area. It has long been known that the central parts of the east and west subarctic North Pacific are HNLC regions. The deep western basin of the Bering Sea is also HNLC, whereas the wide continental shelf of the eastern Bering Sea is not. We carried out a statistical comparison of spatial maps of (1) seafloor depth and (2) chlorophyll a concentration from satellite data. This comparison reveals that shallow waters have, on average, higher peak chlorophyll a concentrations (more intense phytoplankton blooms) than deep waters (p << 0.01). Possible artifacts... |
| Tipo: Text |
Palavras-chave: Phytoplankton; Ocean color; Bathymetry; HNLC; North Pacific; Iron. |
| Ano: 2005 |
URL: https://archimer.ifremer.fr/doc/00232/34337/32758.pdf |
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| Registros recuperados: 369 | |
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