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Auteur Gueroun, S.K.M.; Molinero, J.C.; Piraino, S.; Daly Yahia, M.N.
Titre Population dynamics and predatory impact of the alien jellyfish Aurelia solida (Cnidaria, Scyphozoa) in the Bizerte Lagoon (southwestern Mediterranean Sea) Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Mediterr. Mar. Sci.
Volume 21 Numéro 1 Pages 22-35
Mots-Clés abundance; asexual reproduction rates; aurita cnidaria; common jellyfish; cyanea-capillata; gullmar fjord; mesozooplankton; moon jellyfish; predation; prey selection; prince-william-sound; Scyphomedusae; SW Mediterranean; tokyo bay; zooplankton
Résumé Understanding the life cycle strategies and predatory impact of alien jellyfish species is critical to mitigate the impact that these organisms may have on local populations, biodiversity, and ultimately on the functioning of food webs. In the Mediterranean Sea, little is known about the dynamics of alien jellyfish, despite this biodiversity hotspot being one of the most threatened areas by increasing numbers of alien jellyfish. Here, we investigated the population dynamics and predatory impact of a non-indigenous scyphomedusa, Aurelia solida Browne 1905, in the Bizerte Lagoon, Tunisia. The study was based on bimonthly surveys performed over two consecutive years, from November 2012 to August 2014. Field observations showed that the planktonic phase of A. solida occurs from winter to early summer. Prey composition was investigated by means of gut content and field zooplankton analyses. Calanoid copepods, mollusc larvae, and larvaceans represented the main food items of A. solida. To determine the jellyfish feeding rate and their predatory impact on zooplankton populations, the digestion time for zooplankton prey was assessed at three different temperatures: 13, 18, and 23 degrees C in laboratory conditions, corresponding to the average range of temperatures encountered by A. solida in the Bizerte Lagoon. We found that A. solida consumed 0.5-22.5% and 0.02-37.3% of the daily zooplankton standing stock in 2013 and 2014, respectively. These results indicate a non-negligible but restricted seasonal grazing impact on some mesozooplankton groups, explained by the relatively short lifespan of the medusa stage (5-6 months).
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Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1108-393x ISBN Médium
Région Expédition Conférence
Notes WOS:000524248700003 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2773
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Auteur Hadjadji, I.; Laabir, M.; Frihi, H.; Collos, Y.; Shao, Z.J.; Berrebi, P.; Abadie, E.; Amzil, Z.; Chomérat, N.; Rolland, J.L.; Rieuvilleneuve, F.; Masseret, E.
Titre Unsuspected intraspecific variability in the toxin production, growth and morphology of the dinoflagellate Alexandrium pacificum R.W. Litaker (Group IV) blooming in a South Western Mediterranean marine ecosystem, Annaba Bay (Algeria) Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Toxicon
Volume 180 Numéro Pages 79-88
Mots-Clés Growth; Intraspecific variability; Mediterranean; Toxin profile
Résumé Physiological plasticity gives HABs species the ability to respond to variations in the surrounding environment. The aim of this study was to examine morphological and physiological variability in Alexandrium pacificum R.W. Litaker (Group IV) (former Alexandrium catenella) blooming in Annaba bay, Algeria. Monoclonal cultures of up to 30 strains of this neurotoxic dinoflagellate were established by the germination of single resting cysts from the surface sediment of this southern Mediterranean marine ecosystem. Ribotyping confirmed formally for the first time that A. pacificum is developing in Eastern Algerian waters. Toxin analyses of A. pacificum strains revealed substantial intraspecific variability in both the profile and toxin amount. However, the toxin profile of most strains is characterized by the dominance of GTX6 (up to 96 mol %) which is the less toxic paralytic molecule. The toxin concentrations in the isolated strains varied widely between 3.8 and 30.82 fmol cell−1. We observed an important variation in the growth rate of the studied A. pacificum strains with values ranging from 0.05 to 0.33 d−1. The lag time of the studied strains varied widely and ranged from 4 to 20 days. The intraspecific diversity could be a response to the selection pressure which may be exerted by different environmental conditions over time and which can be genetically and in turn physiologically expressed. This study highlights, for the first time, that the sediment of a limited area holds an important diversity of A. pacificum cysts which give when germinate populations with noticeable physiological plasticity. Consequently, this diversified natural populations allow an exceptional adaptation to specific environmental conditions to outcompete local microalgae and to establish HABs which could explain why this dinoflagellate is successful and expanding worldwide.
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Langue en Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0041-0101 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2775
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Auteur Derolez, V.; Soudant, D.; Malet, N.; Chiantella, C.; Richard, M.; Abadie, E.; Aliaume, C.; Bec, B.
Titre Two decades of oligotrophication: Evidence for a phytoplankton community shift in the coastal lagoon of Thau (Mediterranean Sea, France) Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Estuarine, Coastal and Shelf Science
Volume Numéro Pages 106810
Mots-Clés Eutrophication; Mediterranean coastal lagoon; Nutrients; Oligotrophication; Phytoplankton community shift; Recovery
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Volume de collection Numéro de collection Edition
ISSN 0272-7714 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2776
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Auteur Boulanger, E.; Dalongeville, A.; Andrello, M.; Mouillot, D.; Manel, S.
Titre Spatial graphs highlight how multi-generational dispersal shapes landscape genetic patterns Type Article scientifique
Année (down) 2020 Publication Revue Abrégée Ecography
Volume Numéro Pages
Mots-Clés connectivity; fish populations; flow; genetic connectivity; habitat; Mediterranean Sea; migration rates; models; Mullus surmuletus; mullus-surmuletus; ocean currents; r-package; seascape genetics; spatial graphs; stepping-stone dispersal; unsampled populations
Résumé Current approaches that compare spatial genetic structure of a given species and the dispersal of its mobile phase can detect a mismatch between both patterns mainly due to processes acting at different temporal scales. Genetic structure result from gene flow and other evolutionary and demographic processes over many generations, while dispersal predicted from the mobile phase often represents solely one generation on a single time-step. In this study, we present a spatial graph approach to landscape genetics that extends connectivity networks with a stepping-stone model to represent dispersal between suitable habitat patches over multiple generations. We illustrate the approach with the case of the striped red mullet Mullus surmuletus in the Mediterranean Sea. The genetic connectivity of M. surmuletus was not correlate with the estimated dispersal probability over one generation, but with the stepping-stone estimate of larval dispersal, revealing the temporal scale of connectivity across the Mediterranean Sea. Our results highlight the importance of considering multiple generations and different time scales when relating demographic and genetic connectivity. The spatial graph of genetic distances further untangles intra-population genetic structure revealing the Siculo-Tunisian Strait as an important corridor rather than a barrier for gene flow between the Western- and Eastern Mediterranean basins, and identifying Mediterranean islands as important stepping-stones for gene flow between continental populations. Our approach can be easily extended to other systems and environments.
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Editeur Lieu de Publication Éditeur
Langue English Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0906-7590 ISBN Médium
Région Expédition Conférence
Notes WOS:000533549700001 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2789
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Auteur Lefebvre, C.; Saraux, C.; Heitz, O.; Nowaczyk, A.; Bonnet, D.
Titre Microplastics FTIR characterisation and distribution in the water column and digestive tracts of small pelagic fish in the Gulf of Lions Type Article scientifique
Année (down) 2019 Publication Revue Abrégée Marine Pollution Bulletin
Volume 142 Numéro Pages 510-519
Mots-Clés Ftir; Mediterranean; Microplastics
Résumé This study aims at quantifying and characterising microplastics (MP) distribution in the water column of the NW Mediterranean Sea as well as MP ingestion by the 2 main planktivorous fish of the area, sardine and anchovy. Debris of similar sizes were found in all water column samples and in all but 2 fish guts (out of 169). MP were found in 93% of water column samples with an average concentration of 0.23 ± 0.20 MP·m−3, but in only 12% of sardines (0.20 ± 0.69 MP·ind−1) and 11% of anchovies (0.11 ± 0.31 MP·ind−1). Fibres were the only shape of MP encountered and polyethylene terephthalate was the main polymer identified in water columns (61%), sardines (71%) and anchovies (89%). This study confirms the ubiquity of MP in the Mediterranean Sea and imparts low occurrence in fish digestive tracts.
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Editeur Lieu de Publication Éditeur
Langue Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 0025-326x ISBN Médium
Région Expédition Conférence
Notes WOS:000474319500058 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2568
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