Consulta: creatorFacets:"Catala, Philippe"
Registros recuperados: 7
Data/hora: 07/06/2024 05:36:05

When riverine dissolved organic matter (DOM) meets labile DOM in coastal waters: changes in bacterial community activity and composition
Provedor de dados: 5
Autores: Blanchet, Marine; Pringault, Olivier; Panagiotopoulos, Christos; Lefevre, Dominique; Charriere, Bruno; Ghiglione, Jean-francois; Fernandez, Camila; Aparicio, Fran L.; Marrase, Celia; Catala, Philippe; Oriol, Louise; Caparros, Jocelyne; Joux, Fabien.
Heterotrophic bacterial communities in marine environments are exposed to a heterogeneous mixture of dissolved organic compounds with different bioreactivity that may control both their activity and composition. The coastal environment is an example of a mixing area where recalcitrant allochthonous organic matter from rivers can encounter labile organic matter from marine phytoplanktonic blooms. The objective of this study was to explore the effects of mixed qualities of dissolved organic matter (DOM) on bacterial community activity (BCA) and bacterial community composition (BCC) and to test for a priming effect when DOM sources are added in combination. Coastal marine bacterial communities were incubated separately with a mixture of amino acids and with...
Tipo: Text
Palavras-chave: Dissolved organic matter; Biodegradation; Coastal waters; Bacterial community composition; Priming effect.
Ano: 2017
URL: https://archimer.ifremer.fr/doc/00625/73737/74701.pdf

Spatial comparison of total vs. active bacterial populations by coupling genetic fingerprinting and clone library analyses in the NW Mediterranean Sea
Provedor de dados: 5
Autores: Rodriguez-blanco, Arturo; Ghiglione, Jean-francois; Catala, Philippe; Casamayor, Emilio O.; Lebaron, Philippe.
Spatial distributions of both total (i.e. 16S rDNA-based fingerprints) and active (i.e. 16S rRNA-based fingerprints) bacterial populations, together with total bacterial activity measured by (3)H-leucine incorporation, were studied along a 98 km transect in the NW Mediterranean Sea. Capillary electrophoresis-single strand conformation polymorphism (CE-SSCP) fingerprinting was coupled to a clone library, allowing CE-SSCP peaks identification and the monitoring of the spatial variation of bacterial phylotypes. Up to 80% of the community peaks matched those obtained from clone library sequences, accounting for 86.7% of the total fingerprinting area. A good agreement was found between the relative abundance of Prochlorococcus in the CE-SSCP fingerprints and...
Tipo: Text
Palavras-chave: CE-SSCP fingerprinting; 16S rRNA; Spatial distribution; Bacterial diversity and activity Prochlorococcus; SAR11; Gammaproteobacteria.
Ano: 2009
URL: https://archimer.ifremer.fr/doc/00243/35433/33965.pdf

Enhanced heterotrophic activity in the surface microlayer of the Mediterranean Sea
Provedor de dados: 5
Autores: Obernosterer, Ingrid; Catala, Philippe; Reinthaler, Thomas; Herndl, Gerhard J.; Lebaron, Philippe.
The abundance and activity of heterotrophic and autotrophic organisms were determined in the surface microlayer (SML) at marine and estuarine sites in the NW Mediterranean Sea from May to July 2003. At all study sites, community respiration in the SML exceeded that in the subsurface water (SSW) by factors between 1.7 and 28. The abundance of heterotrophic bacteria and the major groups of the autotrophic community displayed consistent, but low enrichment factors (EF) for the SML (mean 1.3). In contrast, EF for the abundance of heterotrophic nanoflagellates and the concentration of particulate organic carbon were, on average, 4 and 7, respectively. Community respiration rates in the SML were related to the concentration of total organic carbon; however, no...
Tipo: Text
Palavras-chave: Surface microlayer; Community respiration; Net community production; Neuston.
Ano: 2005
URL: https://archimer.ifremer.fr/doc/00243/35435/33960.pdf

Seasonal microbial food web dynamics in contrasting Southern Ocean productivity regimes
Provedor de dados: 5
Autores: Christaki, Urania; Gueneugues, Audrey; Liu, Yan; Blain, Stéphane; Catala, Philippe; Colombet, Jonathan; Debeljak, Pavla; Jardillier, Ludwig; Irion, Solène; Planchon, Frederic; Sassenhagen, Ingrid; Sime Ngando, Telesphore; Obernosterer, Ingrid.
Spatial and seasonal dynamics of microbial loop fluxes were investigated in contrasting productivity regimes in the Indian sector of the Southern Ocean. Observations carried out in late summer (February–March 2018; project MOBYDICK) revealed higher microbial biomasses and fluxes in the naturally iron‐fertilized surface waters of Kerguelen island in comparison to surrounding off‐plateau waters. Differences were most pronounced for bacterial heterotrophic production (2.3‐fold), the abundance of heterotrophic nanoflagellates (HNF; 2.7‐fold). Independent of site, grazing by HNF was the main loss process of bacterial production (80–100%), while virus‐induced mortality was low (&lt; 9%). Combining these results with observations from previous investigations...
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00649/76109/77064.pdf

Spatial patterns of ectoenzymatic kinetics in relation to biogeochemical properties in the Mediterranean Sea and the concentration of the fluorogenic substrate used
Provedor de dados: 5
Autores: Van Wambeke, France; Pulido, Elvira; Catala, Philippe; Dinasquet, Julie; Djaoudi, Kahina; Engel, Anja; Garel, Marc; Guasco, Sophie; Barbara, Marie; Nunige, Sandra; Taillandier, Vincent; Zancker, Birthe; Tamburini, Christian.
Ectoenzymatic activity, prokaryotic heterotrophic abundances and production were determined in the Mediterranean Sea. Sampling was carried out in the sub-surface, the deep chlorophyll maximum layer (DCM), the core of the Levantine intermediate waters and in the deeper part of the mesopelagic layers. Michaelis–Menten kinetics were assessed using a large range of concentrations of fluorogenic substrates (0.025 to 50 µM). As a consequence, Km (Michaelis–Menten half-saturation constant) and Vm (maximum hydrolysis velocity) parameters were determined for both low- and high-affinity enzymes for alkaline phosphatase, aminopeptidase (LAP) and β-glucosidase (βGLU). Based on the constant derived from the high-LAP-affinity enzyme (0.025–1 µM substrate concentration...
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00642/75452/76268.pdf

Impact of dust enrichment on Mediterranean plankton communities under present and future conditions of pH and temperature: an experimental overview
Provedor de dados: 5
Autores: Gazeau, Frédéric; Ridame, Céline; Van Wambeke, France; Alliouane, Samir; Stolpe, Christian; Irisson, Jean-olivier; Marro, Sophie; Grisoni, Jean-michel; De Liège, Guillaume; Nunige, Sandra; Djaoudi, Kahina; Pulido-villena, Elvira; Dinasquet, Julie; Obernosterer, Ingrid; Catala, Philippe; Guieu, Cécile.
In Low Nutrient Low Chlorophyll areas, such as the Mediterranean Sea, atmospheric fluxes represent a considerable external source of nutrients likely supporting primary production especially during stratification periods. These areas are expected to expand in the future due to lower nutrient supply from sub-surface waters caused by enhanced stratification, likely further increasing the role of atmospheric deposition as a source of new nutrients to surface waters. Yet, whether plankton communities will react differently to dust deposition in a warmer and acidified environment remains an open question. The impact of dust deposition both in present and future climate conditions was assessed through three perturbation experiments in the open Mediterranean Sea....
Tipo: Text
Ano: 2021
URL: https://archimer.ifremer.fr/doc/00688/80015/82994.pdf

Distinct bacterial groups contribute to carbon cycling during a naturally iron fertilized phytoplankton bloom in the Southern Ocean
Provedor de dados: 5
Autores: Obernosterer, Ingrid; Catala, Philippe; Lebaron, Philippe; West, Nyree J.
We investigated the contribution of distinct bacterial groups to bulk abundance and leucine incorporation during a spring phytoplankton bloom induced by natural iron fertilization in the Southern Ocean (Kerguelen Ocean and Plateau Compared Study, January-February 2005). Oligonucleotide probes were designed to target five operational taxonomic units (OTUs) at a narrow phylogenetic level (&gt;= 99% identity of the 16S ribosomal ribonucleic acid [rRNA] gene). During the peak of the phytoplankton bloom, the Roseobacter groups NAC11-7 and RCA, the OTUs SAR92 belonging to Gammaproteobacteria, and the Bacteroidetes OTU Agg58 dominated bulk abundance and leucine incorporation. These four OTUs disappeared with the decline of the bloom, when the cosmopolitan groups...
Tipo: Text
Ano: 2011
URL: https://archimer.ifremer.fr/doc/00214/32503/30995.pdf