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| Registros recuperados: 129 | |
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| Pascal, Pierre-yves; Dupuy, C; Richard, P; Haubois, A.g.; Niquil, N. |
| Deposit feeders are able to process a considerable volume of sediment, containing large quantities of associated bacteria. However, conclusions concerning the trophic role played by benthic bacteria in marine sediments are still not fully elucidated. This study deals with bacterivory by the gastropod Hydrobia ulvae, one of the most abundant deposit-feeding species in intertidal mudflats in Western Europe. Ingestion rates of bacteria were determined during grazing experiments using 15N preenriched bacteria. Grazing experiments were performed in order to measure effects of abiotic (temperature, salinity and luminosity) and biotic (bacterial and algal abundances) factors on ingestion rates of bacteria by H. ulvae of an intertidal mudflat (Brouage,... |
| Tipo: Text |
Palavras-chave: Mudflat; Nematodes; Ammonia tepida; Environmental factors; Grazing; Bacteria; Gastropod; Hydrobia ulvae; Deposit feeding. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4781.pdf |
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| Jacq, E; Moal, Jeanne; Samain, Jean-francois; Corre, S; Daniel, J; Nicolas, Jean-louis; Cochard, Jean-claude; Fera, P. |
| Larval rearings were performed with seawater either freshly pumped or after storage in a pond. Concerning bacterial populations these waters were characterized by a high diversity, little sized bacteria whose few of them (1%) were cultivable on Zobell medium. In the tanks, the bacterial ecosystem was modified by the presence of antibiotics, larvae and algae: the diversity was lowered, the cellular volume was increased by a factor 2 to 5, 100% bacteria were cultivable and chloramphenicol resistant, and their metabolism changed. Taxonomic screening showed no differences among the two waters neither at the beginning nor at the end of the rearings. However, depending on the water (stored or not) differences were identified for bacterial physiology and... |
| Tipo: Text |
Palavras-chave: Marine aquaculture; Pond culture; Scallop culture; Ecology; Antibiotics; Organic matter; Grazing; Carbohydrates; Mathematical models; Modelling; Growth; Bacterial diseases; Biological production; Culture tanks; Larvae; Rearing. |
| Ano: 1992 |
URL: http://archimer.ifremer.fr/doc/1992/acte-914.pdf |
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| Mostajir, B; Bustillos-guzman, J; Claustre, H; Rassoulzadegan, F. |
| The egestion of particulate material as well as pigment degradation during microzooplankton grazing on phytoplankton are poorly known processes. In an attempt to evaluate these processes, changes in pigment concentrations within various size fractions were monitored in batch cultures of an assemblage of a pelagic ciliate (Strombidium sulcatum) and a heterotrophic flagellate (Paraphysomonas sp.) feeding on a cyanobacterium (Synechococcus sp.) over a 10-day period. Chlorophyll a, carotenoids and phaeopigments were not found in the 0.1-0.7 mu m fraction while the pigments originally in the 0.7-3.0 mu m fraction (prey) were transferred into the > 3.0 mu m size fraction (predator). During this transfer, the carotenoids (zeaxanthin and B-carotene) were not... |
| Tipo: Text |
Palavras-chave: Pigment; Phéopigment; Broutage; Protozoaire; HPLC; Pigment; Phaeopigment; Grazing; Protozoa; HPLC. |
| Ano: 1998 |
URL: http://archimer.ifremer.fr/doc/00325/43660/43209.pdf |
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| Pascal, P.y.; Dupuy, C; Richard, P; Niquil, N. |
| The majority of sediment dweller foraminifera are deposit feeders. They use their pseudopodia to gather sediment with associated algae, organic detritus and bacteria. Uptake of bacteria by foraminifera have been observed but rarely quantified. We measured uptake of bacteria by the common foraminifera Ammonia tepida using 15N pre-enriched bacteria as tracers. In intertidal flats, seasonal, tidal and circadian cycles induce strong variations in environmental parameters. Grazing experiments were performed in order to measure effects of abiotic (temperature, salinity and irradiance) and biotic (bacterial and algal abundances) factors on uptake rates of bacteria. In mean conditions, A. tepida grazed 78 pgC ind-1 h-1 during the first eight hours of incubation,... |
| Tipo: Text |
Palavras-chave: Trophoecology; Prey abundance; Mudflat; Grazing; Foraminifera; Environmental factor; Bacteria. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4298.pdf |
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| Mathieu, M; Leflaive, J; Ten Hage, L; De Wit, R; Buffan Dubau, E. |
| The aim of the present study was to examine the effects of biofilm-dwelling nematode activity on the oxygen turnover of cultured diatom biofilms. Oxygen microprofiles were simultaneously measured using the microelectrode technique in biofilms incubated with and without nematodes during short-term (24 h) and medium-term (6 d) experiments. During 24 h nycthemeral incubations, maximum oxygen concentrations and oxygen peak depths of microprofiles, as well as net oxygen production rates, were significantly higher in the diatom biofilms with nematodes. These effects might be dependent on the densities of nematodes. In the present study, significant effects were observed at nematode densities exceeding 100 ind. cm(-2), but not at a density <50 ind. cm(-2).... |
| Tipo: Text |
Palavras-chave: Bioturbation; Grazing; Net production rate; Oxygen community metabolism; Microelectrode; Oxygen microprofile; Nematodes; Diatom biofilms. |
| Ano: 2007 |
URL: http://archimer.ifremer.fr/doc/2007/publication-3607.pdf |
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| Rico Villa, Benjamin; Le Coz, Jean-rene; Mingant, Christian; Robert, Rene. |
| Microalgae commonly used as feed for bivalves, Pavlova lutheri (P), Isochrisis affinis galbana (T) and Chaetoceros calcitrans forma pumilum (Cp), were fed to Pacific oyster Crassostrea gigas to assess their nutritional value for larval development and metamorphosis during two experiments. Monospecific, bispecific and trispecific diets were firstly evaluated during 3 weeks from D larvae to young postlarvae. Then bispecific diets, based on different T and Cp proportions, were assessed during a similar period. Concurrently, ingestion was studied through the whole larval and postlarval development for each diet and/or diet mixture. Because lipids are assumed to be a key nutrient for bivalves, biochemical analysis was undertaken on the second set of trials... |
| Tipo: Text |
Palavras-chave: Lipids; Grazing; Metamorphosis; Growth; Larvae; Crassostrea gigas. |
| Ano: 2006 |
URL: http://archimer.ifremer.fr/doc/2006/publication-1707.pdf |
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| Emeline, Creis Bendelac; Ludovic, Delage; Laurent, Vallet; Catherine, Leblanc; Kruse, Inken; Erwan, Ar Gall; Florian, Weinberger; Philippe, Potin. |
| Mechanisms related to the induction of phlorotannin biosynthesis in marine brown algae remain poorly known. Several studies undertaken on fucoid species have shown that phlorotannins accumulate in the algae for several days or weeks after being exposed to grazing, and this is measured by direct quantification of soluble phenolic compounds. In order to investigate earlier inducible responses involved in phlorotannin metabolism, Fucus vesiculosus was studied between 6 and 72 h of grazing by the sea snail Littorina littorea. In this study, the quantification of soluble phenolic compounds was complemented by a Quantitative real-time PCR (qRT-PCR) approach applied on genes that are potentially involved in either the phlorotannin metabolism or stress responses.... |
| Tipo: Text |
Palavras-chave: Phlorotannins; Inducible defense; Gene expression; Grazing; Fucus vesiculosus. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00688/79981/82940.pdf |
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| Chretiennot-dinet, Marie-josèphe; Vaulot, Daniel; Galois, Robert; Spano, Anna-maria; Robert, Rene. |
| The ingestion of 8 algal species by oyster larvae (Crassostrea gigas Thunberg, 1793) was measured by flow cytometry (FCM). In a preliminary experiment, cell size (estimated by light scatter) and chlorophyll fluorescence of 30 algal species were evaluated to select those species which could be mixed together and still be easily discriminated by FCM. Grazing experiments were carried out over 48 h with 6 and 15-day old larvae fed on 3 algal mixtures, each containing 3 different algal species. The concentration of each species was estimated at 0, 6, 12, 24 and 48 h by FCM. Grazing pressure on a given algal species was dependent upon the age of the larvae, the time of the day and the composition of the mixture. Grazing rates of older larvae were about twice... |
| Tipo: Text |
Palavras-chave: Oyster larvae; Crassostrea gigas; Grazing; Algae; Selective feeding; Flow cytometry. |
| Ano: 1991 |
URL: http://archimer.ifremer.fr/doc/00090/20164/17817.pdf |
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| Quevedo, M; Anadon, R. |
| Microzooplankton abundance, biomass and composition were investigated in the coastal waters of Asturias (southern Bay of Biscay) in May 1996. Abundance ranged from 0.7 x 10(3) to 8.5 x 10(3) cell.L-1 The protists community was dominated by aloricate ciliates averaging 82 % of microheterotrophs. Small aloricate ciliates, below 20 mu m in size, contributed 63 % to total ciliate abundance. Carbon biomass ranged from 2.4 to 15.4 mgC.m(-3), averaging 23 % of phytoplankton biomass. Aloricate ciliates were also the dominant component of biomass (56.2 %), but the importance of copepod nauplii increased in terms of carbon, averaging 28.5 % of total biomass. Microzooplankton biomass was significantly correlated with Chi a concentration in the water column.... |
| Tipo: Text |
Palavras-chave: Microzooplancton; Ciliés; Biomasse; Broutage; Golfe de Gascogne; Microzooplankton; Ciliates; Biomass; Grazing; Southern Bay of Biscay. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00324/43564/44061.pdf |
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| Collos, Y; Descolas Gros, C; Mornet, Francoise. |
| During parallel sampling of seawater samples in bottles and in free water (1000-2000 m(3) clay ponds), we have measured phytoplankton biomass, Ribulose biphosphate carboxylase (Rubisco), phosphoenol pyruvate carboxylase, and phosphoenol pyruvate carboxykinase activities and major nutrients (ammonium, nitrate, phosphate, silicate). This was done in two ecosystems: one with high grazing pressure due to the presence of oysters and another with low grazing pressure (no oysters). In the ecosystem subjected to high grazing pressure, anaplerotic carbon fixation by phytoplankton in free water was higher in the light period and could represent 25% of total carbon fixation. Incubating samples in bottles led to a major increase in Rubisco activity (80% in 3 h)... |
| Tipo: Text |
Palavras-chave: Grazing; Carboxylases; Carbon assimilation; Anaplerotic; Ammonium. |
| Ano: 2005 |
URL: http://archimer.ifremer.fr/doc/2005/publication-6437.pdf |
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| Pascal, P.y.; Dupuy, C; Mallet, C; Richard, P; Niquil, N. |
| The fate of benthic bacterial biomass in benthic food webs is a topic of major importance but poorly described. This paper describes an alternative method for evaluation of bacterial grazing rate by meiofauna and macrofauna using bacteria pre-enriched with stable isotopes. Natural bacteria from the sediment of an intertidal mudflat were cultured in a liquid medium enriched with 15NH4Cl. Cultured bacteria contained 2.9% of 15N and were enriched sufficiently to be used as tracers during grazing experiments. Cultured bacteria presented a biovolume (0.21 μm3) and a percentage of actively respiring bacteria (10%) similar to those found in natural communities. The number of Operational Taxon Units found in cultures fluctuated between 56 and 75% of that... |
| Tipo: Text |
Palavras-chave: Tracer; Stable isotope; Sediment; Grazing; Bacteria. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4296.pdf |
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| Pascal, P.y.; Dupuy, C; Richard, P; Rzeznik-orignac, J; Niquil, Nathalie. |
| The fate of the benthic bacterial biomass is a topic of major importance in understanding how softbottom environments function. Because of their high abundance, production and nutritional value, benthic bacteria may constitute an important food resource for benthic fauna. The trophic role of bacteria for a nematode community on the Brouage mudflat (Marennes-Ole´ron-France), dominated by three species: Chromadora macrolaima (64% of the abundance), Daptonema oxycerca (15%) and Ptycholaimellus jacobi (8%), was determined in grazing experiments using 15N pre-enriched bacteria. On intertidal flats, seasonal, tidal and circadian cycles induce strong variations in environmental conditions. Grazing experiments were performed in order to measure the effects of... |
| Tipo: Text |
Palavras-chave: Mudflat; Environmental factor; Grazing; Bacteria; Nematode. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-4295.pdf |
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| HIRATA, Masahiro; FUJITA, Haruhiro; ISHIDA, Jyoken; KITAGAWA, Masayuki; MIYAZAKI, Akira; 平田, 昌弘; 藤田, 晴啓; 石田, 定顕; 北川, 政幸; 宮崎, 昭. |
| http://www.jaals.net/学会誌バックナンバー-投稿規定/ |
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Palavras-chave: Historical change; Grazing; Arabian pastoralist; Motorization; Syria. |
| Ano: 1999 |
URL: http://ir.obihiro.ac.jp/dspace/handle/10322/3266 |
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| Su, Qiang; Huang, Liangmin; Tan, Yehui; Xu, Runlin; Li, Tao; Xu, Zhanzhou; Zhang, Janlin; Qiu, Dajun. |
| Microzooplankton community composition in the north of South China Sea was investigated during autumn (between September and October), 2004. Dilution technique using chlorophyll a (Chl a) was employed to estimate grazing rates and grazing pressure. The results showed that Polymenophorea Oligotrichida was the dominant group with 16 species, and there were 4 species in Oligotrichina and 11 species in Tintinnina. The ciliates abundance ranged from 9 to 102 ind/m3. Instantaneous growth rates of phytoplankton (k) varied from 0.03 / d to 2.13 / d. Grazing rates of microzooplankton(g) ranged between 0.01 / d and 1.06 / d. The grazing pressure on initial phytoplankton stock (Pi) and primary production (Pp) was 0.089 % - 65.23 % and 33.63 % - 86.04 %, respectively.... |
| Tipo: Journal Contribution |
Palavras-chave: Grazing; Community composition; Dilution. |
| Ano: 2007 |
URL: http://hdl.handle.net/1834/5862 |
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| Registros recuperados: 129 | |
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