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Auteur Meddeb, M.; Niquil, N.; Grami, B.; Mejri, K.; Haraldsson, M.; Chaalali, A.; Pringault, O.; Hlaili, A.S. doi  openurl
  Titre (up) A new type of plankton food web functioning in coastal waters revealed by coupling Monte Carlo Markov chain linear inverse method and ecological network analysis Type Article scientifique
  Année 2019 Publication Revue Abrégée Ecol. Indic.  
  Volume 104 Numéro Pages 67-85  
  Mots-Clés Bacterial multivorous food web; biogenic carbon; Coastal waters; continental-shelf; Ecology; ecosystem attributes; flow networks; Food web modeling; grazing impact; gulf; mediterranean sea; model analysis; Network analysis; Seasonal variations; seasonal-dynamics; trophic network; Trophic structure  
  Résumé Plankton food webs (PFW) typology is based on different categories of functioning, according to the dominant processes and the role played by heterotrophic bacteria, small vs large phytoplankton, and small vs large zooplankton. Investigating the structure and the function of planktonic food webs in two SW Mediterranean waters (inshore and marine sites) at four seasons, using inverse (LIM-MCMC) and ecological network (ENA) analyses, we identified a new type of food web, called the “bacterial multivorous food web”. This food web adds to the conventional trophic continuum as previously reported. The “bacterial multivorous food web” present in winter showed the lowest primary production among seasons, but highest bacterial production. Several food web ratios characterized this new typology e.g. picophytoplankton net primary production to total primary production varied from 0.20 to 0.28; bacterial to primary production ratio is higher than values reported in global scale (congruent to 1); bacterial net production to the potential protozoan prey net production was high (>0.2). In this special food web, carbon was mostly recycled, with a moderate fraction channeled to deep waters, which lead to a higher retention of carbon inside the ecosystem. This winter PFW also seemed to be the most organized, specialized, stable and mature, as related to common interpretations of ENA. The spring was characterized by herbivorous food web, with highest activity coinciding with low stability. Although less usual, the herbivorous pathway was also observed during summer, in inshore waters. The autumn food webs, which functioned as multivorous or microbial food webs, appeared to be stable and mature. Finally, our study demonstrates the usefulness of food web models derived ratios combined with ecological network analysis indices to conduct evaluation of the structure and functioning of ecosystems and potentially to support management decisions in marine environment.  
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  ISSN 1470-160x ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2596  
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Auteur van der Heide, T.; Govers, L.L.; de Fouw, J.; Olff, H.; van der Geest, M.; van Katwijk, M.M.; Piersma, T.; van de Koppel, J.; Silliman, B.R.; Smolders, A.J.P.; van Gils, J.A. url  openurl
  Titre (up) A three-stage symbiosis forms the foundation of seagrass ecosystems Type Article scientifique
  Année 2012 Publication Revue Abrégée Science  
  Volume 336 Numéro Pages 1432-1434  
  Mots-Clés mutualistic networks zostera-marina biodiversity bivalves sulfide architecture diversity sediments bacteria mollusca  
  Résumé Seagrasses evolved from terrestrial plants into marine foundation species around 100 million years ago. Their ecological success, however, remains a mystery because natural organic matter accumulation within the beds should result in toxic sediment sulfide levels. Using a meta-analysis, a field study, and a laboratory experiment, we reveal how an ancient three-stage symbiosis between seagrass, lucinid bivalves, and their sulfide-oxidizing gill bacteria reduces sulfide stress for seagrasses. We found that the bivalve-sulfide-oxidizer symbiosis reduced sulfide levels and enhanced seagrass production as measured in biomass. In turn, the bivalves and their endosymbionts profit from organic matter accumulation and radial oxygen release from the seagrass roots. These findings elucidate the long-term success of seagrasses in warm waters and offer new prospects for seagrass ecosystem conservation.  
  Adresse [van der Heide, Tjisse; Olff, Han] Univ Groningen, CEES, Community & Conservat Ecol Grp, NL-9700 CC Groningen, Netherlands. [Govers, Laura L.; van Katwijk, Marieke M.] Radboud Univ Nijmegen, Dept Environm Sci, Inst Water & Wetland Res, Fac Sci, NL-6525 AJ Nijmegen, Netherlands. [de Fouw, Jimmy; van der Geest, Matthijs; Piersma, Theunis; van Gils, Jan A.] NIOZ Royal Netherlands Inst Sea Res, Dept Marine Ecol, NL-1790 AB Den Burg, Texel, Netherlands. [Piersma, Theunis] Univ Groningen, CEES, Anim Ecol Grp, NL-9700 CC Groningen, Netherlands. [van de Koppel, Johan] NIOZ Royal Netherlands Inst Sea Res, Ctr Estuarine & Marine Ecol, NL-4400 AC Yerseke, Netherlands. [Silliman, Brian R.] Univ Florida, Dept Biol, Gainesville, FL 32611 USA. [Smolders, Alfons J. P.] Radboud Univ Nijmegen, Inst Water & Wetland Res, Dept Aquat Ecol & Environm Biol, Fac Sci, NL-6525 AJ Nijmegen, Netherlands. van der Heide, T (reprint author), Univ Groningen, CEES, Community & Conservat Ecol Grp, POB 11103, NL-9700 CC Groningen, Netherlands t.van.der.heide@rug.nl  
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  ISSN 0036-8075 ISBN Médium  
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  Notes ISI Document Delivery No.: 958BT Times Cited: 0 Cited Reference Count: 27 van der Heide, Tjisse Govers, Laura L. de Fouw, Jimmy Olff, Han van der Geest, Matthijs van Katwijk, Marieke M. Piersma, Theunis van de Koppel, Johan Silliman, Brian R. Smolders, Alfons J. P. van Gils, Jan A. “Waddenfonds” program; Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)-WOTRO[W.01.65.221.00]; NWO-VIDI[864.09.002]; NSF; Andrew Mellon Foundation; Royal Netherlands Academy We thank G. Quaintenne and H. Blanchet for their help with the collection of Loripes; J. Eygensteyn and E. Pierson for technical assistance; and G. J. Vermeij, H. de Kroon, T. J. Bouma, E. J. Weerman, and C. Smit for their comments on the manuscript. T.v.d.H. was financially supported by the “Waddenfonds” program; M.v.d.G. and T.P. by the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)-WOTRO Integrated Programme grant W.01.65.221.00 awarded to T.P.; and J.d.F. and J.v.G. by the NWO-VIDI grant 864.09.002 awarded to J.v.G. B.S. was supported by an NSF CAREER award, the Andrew Mellon Foundation, and the Royal Netherlands Academy Visiting Professorship. The authors declare no conflicts of interest. A detailed description of all materials and methods, sources, as well as supplementary information are available as supplementary materials. The data are deposited in DRYAD at http://dx.doi.org/10.5061/dryad.210mp. Amer assoc advancement science Washington Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ 734 collection 1381  
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Auteur Fouilland, E.; Tolosa, I.; Bonnet, D.; Bouvier, C.; Bouvier, T.; Bouvy, M.; Got, P.; Le Floc'h, E.; Mostajir, B.; Roques, C.; Sempéré, R.; Sime-Ngando, T.; Vidussi, F. url  doi
openurl 
  Titre (up) Bacterial carbon dependence on freshly produced phytoplankton exudates under different nutrient availability and grazing pressure conditions in coastal marine waters Type Article scientifique
  Année 2014 Publication Revue Abrégée FEMS microbiology ecology  
  Volume 87 Numéro 3 Pages 757-769  
  Mots-Clés bacteria; carbon coupling; coastal waters; interactions; phytoplankton  
  Résumé The effects of grazing pressure and inorganic nutrient availability on the direct carbon transfer from freshly produced phytoplankton exudates to heterotrophic bacteria biomass production were studied in Mediterranean coastal waters. The short-term incorporation of (1)(3)C (H(1)(3)CO(3)) in phytoplankton and bacterial lipid biomarkers was measured as well as the total bacterial carbon production (BP), viral lysis and the microbial community structure under three experimental conditions: (1) High inorganic Nutrient and High Grazing (HN + HG), (2) High inorganic Nutrient and Low Grazing (HN + LG) and (3) under natural in situ conditions with Low inorganic Nutrient and High Grazing (LN + HG) during spring. Under phytoplankton bloom conditions (HN + LG), the bacterial use of freshly produced phytoplankton exudates as a source of carbon, estimated from (1)(3)C enrichment of bacterial lipids, contributed more than half of the total bacterial production. However, under conditions of high grazing pressure on phytoplankton with or without the addition of inorganic nutrients (HN + HG and LN + HG), the (1)(3)C enrichment of bacterial lipids was low compared with the high total bacterial production. BP therefore seems to depend mainly on freshly produced phytoplankton exudates during the early phase of phytoplankton bloom period. However, BP seems mainly relying on recycled carbon from viral lysis and predators under high grazing pressure.  
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  ISSN 1574-6941 ISBN Médium  
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  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 444  
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Auteur Ram, P.A.S.; Mari, X.; Brune, J.; Torreton, J.P.; Chu, V.T.; Raimbault, P.; Niggemann, J.; Sime-Ngando, T. doi  openurl
  Titre (up) Bacterial-viral interactions in the sea surface microlayer of a black carbon-dominated tropical coastal ecosystem (Halong Bay, Vietnam) Type Article scientifique
  Année 2018 Publication Revue Abrégée Elementa-Sci. Anthrop.  
  Volume 6 Numéro Pages 13  
  Mots-Clés dissolved organic-matter; marine; communities; seawater; lysogeny; black carbon; variability; viruses; waters; aquatic ecosystems; hexane soot; ocean surface; sea surface microlayer; tropical coastal ocean; viral lysis; virus-bacteria interaction  
  Résumé Increasing human activity has raised concerns about the impact of deposition of anthropogenic combustion aerosols (i.e., black carbon; BC) on marine processes. The sea surface microlayer (SML) is a key gate for the introduction of atmospheric BC into the ocean; however, relatively little is known of the effects of BC on bacteria-virus interactions, which can strongly influence microbially mediated processes. To study the impact of BC on bacteria-virus interactions, field investigations involving collection from the SML and underlying water were carried out in Halong Bay (Vietnam). Most inorganic nutrient concentrations, as well as dissolved organic carbon, were modestly but significantly higher (p = 0.02-0.05) in the SML than in underlying water. The concentrations of particulate organic carbon (though not chlorophyll a) and of total particulate carbon, which was composed largely of particulate BC (mean = 1.7 +/- 6.4 mmol L-1), were highly enriched in the SML, and showed high variability among stations. On average, microbial abundances (both bacteria and viruses) and bacterial production were 2- and 5fold higher, respectively, in the SML than in underlying water. Significantly lower bacterial production (p < 0.01) was observed in the particulate fraction (> 3 mu m) compared to the bulk sample, but our data overall suggest that bacterial production in the SML was stimulated by particulate BC. Higher bacterial production in the SML than in underlying water supported high viral lytic infection rates (from 5.3 to 30.1%) which predominated over percent lysogeny (from undetected to 1.4%). The sorption of dissolved organic carbon by black carbon, accompanied by the high lytic infection rate in the black carbon-enriched SML, may modify microbially mediated processes and shift the net ecosystem metabolism (ratio of production and respiration) to net heterotrophy and CO2 production in this critical layer between ocean and atmosphere.  
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  ISSN 2325-1026 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2276  
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Auteur Ben Ouada, S.; Ben Ali, R.; Cimetiere, N.; Leboulanger, C.; Ben Ouada, H.; Sayadi, S. doi  openurl
  Titre (up) Biodegradation of diclofenac by two green microalgae: Picocystis sp. and Graesiella sp Type Article scientifique
  Année 2019 Publication Revue Abrégée Ecotox. Environ. Safe.  
  Volume 186 Numéro Pages Unsp-109769  
  Mots-Clés algae; Biodegradation; Biotransformation; bisphenol-a; contaminants; cyanobacteria; Diclofenac; Extremophiles; light-intensity; Microalgae; pharmaceuticals diclofenac; removal; Removal; temperature; transformation products  
  Résumé The aim of the present study was to provide an integrated view of algal removal of diclofenac (DCF). Two isolated microalgal strains Picocystis sp. and Graesiella sp. were cultivated under different DCF concentrations and their growth, photosynthetic activity and diclofenac removal efficiency were monitored. Results showed that DCF had slight inhibitory effects on the microalgal growth which did not exceed 21% for Picocystis and 36% for Graesiella after 5 days. Both species showed different patterns in terms of removal efficiency. In presence of Picocystis sp., the amounts of removed DCF were up to 73%, 43% and 25% of 25, 50 and 100 mg L-1 respectively; whereas only 52%, 28% and 24% were removed in the presence of Graesiella at same DCF tested concentrations. DCF removal was insured mainly by biodegradation. To better reveal the mechanism involved, metabolites analyses were performed. Two DCF biodegradation/biotransformation products were detected in presence of Picocystis. This study indicated that Picocystis performed a satisfactory growth capacity and DCF removal efficiency and thus could be used for treatment of DCF contaminated aqueous systems.  
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  ISSN 0147-6513 ISBN Médium  
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  Notes WOS:000496901100040 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2657  
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