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Registros recuperados: 13
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Algicidal effects of Zostera marina L. and Zostera noltii Hornem. extracts on the neuro-toxic bloom-forming dinoflagellate Alexandrium catenella ArchiMer
Laabir, Mohamed; Grignon-dubois, Micheline; Masseret, Estelle; Rezzonico, Bernadette; Soteras, Giselle; Rouquette, Manuel; Rieuvilleneuve, Fabien; Cecchi, Philippe.
The inhibitory effects of crude extracts of Zostera marina L and Zostera noltii Hornemann on the growth of the toxic red tide dinoflagellate Alexandrium catenella were investigated through bio-assays. Methanolic and aqueous extracts were prepared from fresh and detrital leaves of Z. marina and Z. noltii collected in the Thau lagoon and Arcachon bay (France). All the extracts exhibited significant inhibition of A. catenella growth, whatever the species and without the need of continuous addition of extracts. The effective concentrations (EC50) varied in the range 0.036-0.199 g L-1 for Z. noltii and 0.036-0.239 g L-1 for Z. marina. Methanolic extracts prepared from fresh plant tissues were the most potent, with EC50 of 0.036-0.039 and 0.036-0.045 g L-1, for...
Tipo: Text Palavras-chave: Growth inhibition; Allelopathy; Alexandrium catenella; Zostera marina; Zostera noltii; Phenolics.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00170/28095/26720.pdf
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Are epiphytes a significant component of intertidal Zostera noltii beds? ArchiMer
Lebreton, Benoit; Richard, Pierre; Radenac, Gilles; Bordes, Monique; Breret, Martine; Arnaud, Christophe; Mornet, Francoise; Blanchard, Gerard F..
The role of epiphytes in an intertidal Zostera noltii seagrass bed in Marennes-Oleron Bay was assessed in comparison with the other main benthic primary producers (Z. noltii, microphytobenthos) at two bathymetric levels and on a seasonal basis. Assemblage and biomass of epiphytes were studied using scanning electron microscopy (SEM). Z noltii and its detrital matter followed a typical seasonal pattern: microphytobenthos was present in large quantities throughout the year representing 21% of the total biomass while detrital matter, above-ground parts and below-ground parts accounted for 65, 9 and 5%, respectively. Only two species of epiphytic diatoms, Cocconeis scutellum and Cocconeis placentula, were observed on seagrass leaves. Epiphyte biomass was very...
Tipo: Text Palavras-chave: SEM; Cocconeis spp.; Epiphyte diatom; Microphytobenthos; Zostera noltii; Intertidal seagrass bed; Primary producer.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6589.pdf
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Coastal hydrodynamics in a windy lagoon ArchiMer
Alekseenko, Elena; Roux, Bernard; Sukhinov, A.; Kotarba, R.; Fougere, D..
The nonlinear hydrodynamics (3D RANS model) in a wide semi-enclosed windy lagoonal ecosystem is accurately investigated in the context of analyzing the limiting conditions of the recovery of submerged aquatic vegetation (SAV). Among the main natural hydrodynamical forcings, we consider the wind effect. We mainly focus attention to characteristic velocities (free surface and bottom) and to free surface elevation in the nearshore regions (with shallow water) where SAV were severely damaged in the past decades. Our main result relates to wind effects that form downwind coastal jets, alongshore, in shallow water areas, due to Berre bathymetry. Such coastal jets, which were never described previously in Berre lagoon literature, give rise to substantial bottom...
Tipo: Text Palavras-chave: Hydrodynamics; Berre lagoon; Current structures; Zostera noltii; Seagrass protection.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00144/25511/24704.pdf
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Cycle de l'azote à l' interface eau-sédiment dans le Bassin d'Arcachon : rôle des bactéries dans les processus de perte en azote (nitrification-dénitrification) ArchiMer
Riou, Stéphane Alain.
Bacterial nitrification and denitrification were studied in the sediments of the Bassin d'Arcachon, a macrotidallagoon located in the Southwestern Atlantic French coast colonized by extensive Zostera noltii  meadows. Nitrifiers were enumerated by MPN method. Densities were law : from 102 to 104 bacteria per ml of sediment presenting an increase during winter. Nitrifying activities were measured by NH4+  accumulation N-serve block technique. Activities were ranged from 0 to 90 µmol m-2 h-1 and nitrification represented 120-140 mmol m-2 yr-1 for intertidal sediments. The 15N  isotope pairing technique was applied to sediment samples from the whole bay for determining the denitrification rates. Average rates were 10-20 µmol m·2 h-1 with a maximum of 75 µmol...
Tipo: Text Palavras-chave: Nitrification; Dénitrification; Sédiment; Zostera noltii; Lagune; NPP; N6SERVE; 15N; Nitrification; Denitrification; Sediment; Zostera noltii; Marine laboon; MPN; N-serve; 15N.
Ano: 1999 URL: http://archimer.ifremer.fr/doc/00443/55439/56959.pdf
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Dynamics and sources of suspended particulate organic matter in the Marennes-Oléron oyster farming bay: Insights from stable isotopes and microalgae ecology ArchiMer
Malet, Nathalie; Sauriau, Pierre-guy; Ryckaert, Mireille; Malestroit, Pascale; Guillou, Gael.
The aim of this study was to distinguish between sources of the complex variety of Marennes-Oléron Bay suspended particulate organic matter (SPOM) contributing to the tropho-dynamics of the Marennes-Oléron oyster farming bay. Basic biomarkers (Chl a, C/N and POC/Chl a ratios), carbon and nitrogen stable isotopes from SPOM were analyzed and the microalgae community was characterized. The sampling strategy was bimonthly from March 2002 to December 2003; samples were taken from an intertidal mudflat. Four main sources contributed to the SPOM pool: terrigenous input from rivers, neritic phytoplankton, resuspended microphytobenthos and periodic inputs from intertidal Zostera noltii meadows. Seasonal fluctuations were observed in both years of the study period:...
Tipo: Text Palavras-chave: Heatwave; Zostera noltii; Mudflat; Microphytobenthos; Phytoplankton; Suspended particulate organic matter; Marennes Oléron Bay.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-4313.pdf
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Effect of plant photosynthesis, carbon sources and ammonium availability on nitrogen fixation rates in the rhizosphere of Zostera noltii ArchiMer
Welsh, Dt; Bourgues, S; Dewit, R; Auby, Isabelle.
Rates of nitrogen fixation (measured as acetylene reduction) in the rhizosphere of the seagrass Zostera noltii were highly dependent upon plant photosynthetic activity being significantly stimulated at elevated CO2 concentrations and by light, both in the short-term and over diurnal cycles. Stimulation by light became insignificant when 5 mM sucrose was added to the sediment porewater, indicating that in the absence of added carbon sources, light stimulation was due to direct inputs of plant photosynthate to the rhizosphere. Addition of a range of carbon sources to the rhizosphere sediment stimulated rates of acetylene reduction, with this stimulation being significant for sucrose and lactate. Surprisingly, whilst low additions of ammonium to the sediment...
Tipo: Text Palavras-chave: Acetylene reduction; Nitrogen fixation; Rhizosphere; Zostera noltii; Plant photosynthesis; Root exudates; Carbon sources; Ammonium.
Ano: 1997 URL: http://archimer.ifremer.fr/doc/00151/26266/24350.pdf
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Entangled effects of allelic and clonal (genotypic) richness in the resistance and resilience of experimental populations of the seagrass Zostera noltii to diatom invasion ArchiMer
Massa, Sonia I.; Paulino, Cristina M.; Serrao, Ester A.; Duarte, Carlos M.; Arnaud-haond, Sophie.
Background: The relationship between species diversity and components of ecosystem stability has been extensively studied, whilst the influence of the genetic component of biodiversity remains poorly understood. Here we manipulated both genotypic and allelic richness of the seagrass Zostera noltii, in order to explore their respective influences on the resistance of the experimental population to stress. Thus far intra-specific diversity was seldom taken into account in management plans, and restoration actions showed very low success. Information is therefore needed to understand the factors affecting resistance and resilience of populations. Results: Our results show a positive influence of both allelic and genotypic richness on the resistance of...
Tipo: Text Palavras-chave: Allelic richness; Genotypic richness; Resistance; Resilience; Zostera noltii; Biotic stress; Seagrass.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00166/27748/25946.pdf
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Long-term evolution (1988-2008) of Zostera spp. meadows in Arcachon Bay (Bay of Biscay) ArchiMer
Plus, Martin; Dalloyau, Sebastien; Trut, Gilles; Isabelle, Auby; De Montaudouin, Xavier; Emery, Eric; Claire, Noel; Christophe, Viala.
The spatial variability of seagrass meadows in Arcachon Bay, was studied between 1988 and 2008 using a combination of mapping techniques based on aerial photographs for intertidal dwarf-grass (Zostera noltti) beds and acoustic sonar for permanently submerged eelgrass (Zostera marina) populations. The results show a severe decline over the period for both species, as well as an acceleration of the decline since 2005 for Z. noltii. The total surface regression over the studied period is estimated to be 22.8 km(2) for Z. noltii and 2.7 km(2) for Z. marina, which represent declines of 33 and 74% respectively. Environmental data time series spanning the same period were investigated in order to seek the causes for such a decline. The calculated inter-annual...
Tipo: Text Palavras-chave: Seagrass; Temporal evolution; Aerial photography; Acoustic sonar; Zostera noltii; Zostera marina; Arcachon Bay.
Ano: 2010 URL: http://archimer.ifremer.fr/doc/00003/11376/7969.pdf
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Origin and composition of sediment organic matter in a coastal semi-enclosed ecosystem: An elemental and isotopic study at the ecosystem space scale ArchiMer
Dubois, S.; Savoye, N.; Gremare, Antoine; Plus, Martin; Charlier, K.; Beltoise, A.; Blanchet, Hugues.
The origin and composition of sediment organic matter (SOM) were investigated together with its spatial distribution in the Arcachon Bay - a macrotidal lagoon that shelters the largest Zostera noltii meadow in Europe - using elemental and isotopic ratios. Subtidal and intertidal sediments and primary producers were both sampled in April 2009. Their elemental and isotopic compositions were assessed. Relative contributions of each source to SOM were estimated using a mixing model. The SOM composition tended to be homogeneous over the whole ecosystem and reflected the high diversity of primary producers in this system. On average, SOM was composed of 25% of decayed phanerogams, 19% of microphytobenthos, 20% of phytoplankton, 19% of river SPOM and 17% of...
Tipo: Text Palavras-chave: Sediment organic matter; Primary producers; C and N stable isotopes; Zostera noltii; Arcachon Bay.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00073/18426/16059.pdf
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Rôle des herbiers de Zostères (Zostera noltii) sur la dynamique sédimentaire du Bassin d'Arcachon ArchiMer
Ganthy, Florian.
The intertidal flats in the Arcachon lagoon are extensively colonized by seagrass meadows of Zostera noltii. The last ten years these meadows experienced a drastic regression of their surface area. Understanding the impact of seagrass on hydrodynamics and sediment dynamics is required to anticipate the consequences of meadows regression on the sediment dynamics of the Arcachon lagoon. Flume experiments with natural seagrass highlighted a strong velocity attenuation associated with a turbulence increase near the bed within seagrass canopies. An increase in sediment protection from erosion and in deposition fluxes related to the seagrass growth was found. Erosion tests showed seasonal variability of sediment resistance against erosion associated with changes...
Tipo: Text Palavras-chave: Phanérogames; Zostera noltii; Croissance saisonnière; Dynamique sédimentaire; Bassin d’Arcachon; Seagrasses; Zostera noltii; Seasonal growth; Sediment dynamics; Arcachon lagoon.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00060/17170/14672.pdf
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Short-term interactions between phytoplankton and intertidal seagrass vegetation in a coastal lagoon (Bassin d'Arcachon, SW France) ArchiMer
De Wit, Rutger; Troussellier, Marc; Courties, Claude; Buffan-dubau, Evelyne; Lemaire, Emmanuelle.
We experimentally simulated the temporality of the interactions between intertidal seagrasses and phytoplankton in the context of nutrient enrichment from continental origin. Phytoplankton development was retarded after 1-day exposure to intertidal Zostera noltii Hornemann vegetation samples, with respect to control treatments. This was not explained by resource competition and we hypothesized a direct interference between seagrass leaves and phytoplankton. After separation from the vegetation in 5-day incubations, the final yield of large phytoplankton, mainly diatoms and haptophytes, was determined by nutrient loading. In contrast, Synechococcus-like cells (SYN), phototrophic picoeukaryotes and nanophytoplankton decreased after day 3, most likely due to...
Tipo: Text Palavras-chave: Competition; Allelopathy; Zostera noltii; Sediment; Intertidal vegetation; Flow cytometry; Photosynthetic pigments.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00106/21717/19414.pdf
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Trophic importance of diatoms in an intertidal Zostera noltii seagrass bed: Evidence from stable isotope and fatty acid analyses ArchiMer
Lebreton, Benoit; Richard, Pierre; Galois, Robert; Radenac, Gilles; Pfleger, Camille; Guillou, Gael; Mornet, Francoise; Blanchard, Gerard F..
A current predominant paradigm emphasizes the role of epiphytic algae for invertebrates in most seagrass food webs. However, in some intertidal Zostera noltii beds, epiphyte biomass is very low compared to microphytobenthos and seagrass biomasses. We assessed the role of microphytobenthos in a temperate intertidal Z. noltii bed by combining stable isotope and fatty acid (FA) analyses on primary producers, composite sources suspended particulate organic matter (SPOM) and sediment surface organic matter (SSOM) and the main macrofaunal consumers. Z. noltii showed high delta C-13 (-9.9 parts per thousand) and high 18:2(n-6) and 18:3(n-3) contents. Microphytobenthos was slightly more C-13-depleted (-15.4 parts per thousand) and had high levels of diatom...
Tipo: Text Palavras-chave: Food web; Intertidal seagrass bed; Microphytobenthos; Zostera noltii; Stable isotope ratio; Fatty acid profiles; European Atlantic coast.
Ano: 2011 URL: http://archimer.ifremer.fr/doc/00035/14640/12051.pdf
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Особенности морфоструктуры и комплекс морфометрических параметров жизненного состояния особей морской травы Zostera nolti Hornem IBSS Repository
Александров, В. В..
Изучение морфоструктуры особей Z. noltii проводили в июне – августе 2000-2001 г. в бухте Стрелецкая и в устье р. Черная (район Севастополя, Черное море). Определяли 38 метрических и 5 аллометрических параметров материнских и дочерних побегов. Морфометрические параметры особей Z. noltii. характеризуются правосторонней асимметрией и высоким коэффициентом вариации. Наиболее велики изменчивость и асимметрия параметров корневищ и дочерних побегов. Факторный анализ корреляций между признаками, (R-техника) позволил определить их информативную ценность для оценки жизненного состояния особей Z. noltii. Выделено 5 факторов, которые интерпретируются как функциональные группы признаков: параметры листьев материнских побегов, параметры подземной сферы материнских...
Tipo: Journal Contribution Palavras-chave: Zostera noltii; Жизненное состояние; Изменчивость признаков; Морфологическая структура растения; Факторный анализ; Vitality; Morphostructure Plant morphology Plant morphology http://aims.fao.org/aos/agrovoc/c_13434.
Ano: 2003 URL: http://repository.ibss.org.ua/dspace/handle/99011/542
Registros recuperados: 13
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