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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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| Montanie, Helene; Ory, Pascaline; Orvain, Francis; Delmas, Daniel; Dupuy, Christine; Hartmann, Hans J.. |
| In shallow macrotidal ecosystems with large intertidal mudflats, the sediment-water coupling plays a crucial role in structuring the pelagic microbial food web functioning, since inorganic and organic matter and microbial components (viruses and microbes) of the microphytobenthic biofilm can be suspended toward the water column. Two experimental bioassays were conducted in March and July 2008 to investigate the importance of biofilm input for the pelagic Microbial and Viral Loops. Pelagic inocula (< 0.6 μ- and < 10 μ filtrates) were diluted either with < 30 kDa-ultrafiltered seawater or with this ultrafiltrate enriched with the respective size-fractionated benthic biofilm or with < 30 kDa-benthic compounds (BC). The kinetics of heterotrophic... |
| Tipo: Text |
Palavras-chave: Mudflats; Virus; Bacteria; HNF; Coastal water. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00166/27691/25883.pdf |
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| Auguet, Jean-christophe; Montanie, Helene; Hartmann, Hans; Lebaron, P.; Casamayor, E. O.; Catala, P.; Delmas, Daniel. |
| Batch culture experiments using viral enrichment were conducted to test the response of a coastal bacterial community to autochthonous (i.e., co-existing) or allochthonous riverine viruses. The effects of viral infections on bacterial dynamics and activity were assessed by epifluorescence microscopy and thymidine incorporation, respectively, whereas the effect of viral infection on bacterial community composition was examined by polymerase chain reaction-single strand conformation polymorphism 16S ribosomal RNA fingerprinting. The percentages of high nucleic acid-containing cells, evaluated by flow cytometry, were significantly correlated (r (2) = 0.91, n = 12, p < 0.0001) to bacterial production, making this value a good predictor of active cell... |
| Tipo: Text |
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| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6636.pdf |
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| Dupuy, Christine; Mallet, Clarisse; Guizien, Katell; Montanie, Helene; Breret, Martine; Mornet, Francoise; Fontaine, Camille; Nerot, Caroline; Orvain, Francis. |
| Resuspension thresholds in terms of friction velocity were experimentally quantified for the prokaryotes, protists and for the first time, viruses of intertidal mudflat biofilms. Differences in resuspension thresholds could be related to the type, behaviour and size of microorganisms and their association with particles. Free microorganisms (viruses, bacteria and some nanoflagellates) were resuspended by weak flow at friction velocities lower than 2 cm s- 1. Chlorophyll a, some nanoflagellates and attached bacteria were resuspended together with the bed’s muddy sediment, which required friction velocities larger than 3 cm s- 1. Diatoms smaller than 60 μm were resuspended at velocities between 3 and 5 cm s- 1, while those larger than 60 μm were resuspended... |
| Tipo: Text |
Palavras-chave: Viruses; Microorganisms; Resuspension; Benthic-pelagic coupling; Spatial distribution; Mudflat. |
| Ano: 2014 |
URL: http://archimer.ifremer.fr/doc/00168/27922/26196.pdf |
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