Consulta: creatorFacets:"Pascal, Pierre-yves"
Registros recuperados: 4
Data/hora: 03/06/2024 05:27:47

Influence of environment factors on bacterial ingestion rate of the deposit-feeder Hydrobia ulvae and comparison with meiofauna
Provedor de dados: 5
Autores: 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

Influences of geothermal sulfur bacteria on a tropical coastal food web
Provedor de dados: 5
Autores: Pascal, Pierre-yves; Dubois, Stanislas; Goffette, Anais; Lepoint, Gilles.
The activity of the geothermal plant at Bouillante in Guadeloupe (French West Indies) releases thioautotrophic bacteria into the coastal environment. Fish counts reveal that fish abundance increases with higher availability of this bacterial resource. In order to evaluate the trophic role of these bacteria, isotopic compositions (C, N, S) of potential consumers were evaluated on transects at increasing distance from the source of bacteria. The 3 mobile fish species examined (Abudefduf saxatilis, Acanthurus bahianus, and Stegastes partitus) ingested and assimilated chemosynthetic bacteria. Similarly, the isotopic composition of the mobile sea urchin Diadema antillarum was different close to the discharge channel, suggesting a diet mainly composed of sulfur...
Tipo: Text
Palavras-chave: Shallow vent; Food web; Sulfur bacteria; Stable isotope.
Ano: 2017
URL: http://archimer.ifremer.fr/doc/00404/51511/52256.pdf

Devenir des bactéries dans les réseaux trophiques des vasières intertidales : le cas de brouage (Baie de Marennes-Oléron)
Provedor de dados: 5
Autores: Pascal, Pierre-yves.
Bacteria are highly abundant and productive in intertidal mudflat sediments. By analogy  with pelagic system, it has been suggested that bacteria play an important role in benthic food  web. Due to technical difficulties, numbers of studies dealing with benthic bacterivory are not  numerous and give conflicting results. A method using community of 15N enriched bacteria as  tracer was developed in order to measure grazing of meiofauna and macrofauna. Since enriched  bacteria present characteristics of size, activity and diversity close to natural ones, bias due to  selective bacterial ingestion by grazers are limited. Due to tidal cycles, intertidal mudflat  constitutes highly variable environment at short time scale. Since those variations may influence...
Tipo: Text
Palavras-chave: Stable isotope; Hydrobia ulvae; Foraminifera; Copepod; Nematode; Bacteria; Mudflat; Trophic foodweb; Isotope stable; Hydrobia ulvae; Foraminifère; Copépode; Nématode; Bactérie; Vasière; Réseau trophique.
Ano: 2008
URL: http://archimer.ifremer.fr/doc/2008/these-4778.pdf

Trophic role of large benthic sulfur bacteria in mangrove sediment
Provedor de dados: 5
Autores: Pascal, Pierre-yves; Dubois, Stanislas; Boschker, Henricus T. S.; Gros, Olivier.
Large filamentous sulfur-oxidizing bacteria belonging to the Beggiatoacae family can cover large portions of shallow marine sediments surrounding mangroves in Guadeloupe (French West Indies). In order to assess the importance of Beggiatoa mats as an infaunal food source, observations were conducted of the area within mats and at increasing distances from mats. We used natural isotopic compositions and a C-13 enrichment study. Both revealed an ingestion of bacterial mats by associated meiofauna, dominated by rotifers and to a smaller extent by small polychaetes and nematodes. Compared to adjacent sites, sediment covered by bacterial mats presented a higher abundance of diatoms, whereas the total biomass of bacteria did not vary. This constant bacterial...
Tipo: Text
Palavras-chave: Beggiatoa; Mangrove; Benthic food web; Sulfur bacteria; Meiofauna; Nematode; Rotifers; Stable isotope.
Ano: 2014
URL: https://archimer.ifremer.fr/doc/00248/35919/34449.pdf