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Auteur Chu, T.V.; Torréton, J.-P.; Mari, X.; Nguyen, H.M.T.; Pham, K.T.; Pham, T.T.; Bouvier, T.; Bettarel, Y.; Pringault, O.; Bouvier, C.; Rochelle-Newall, E.
Titre Nutrient ratios and the complex structure of phytoplankton communities in a highly turbid estuary of Southeast Asia Type Article scientifique
Année 2014 Publication Revue Abrégée Environ Monit Assess
Volume 186 Numéro 12 Pages 8555-8572
Mots-Clés Hab; Phytoplankton diversity; Southeast Asia; vietnam
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Éditeur de collection Titre de collection Titre de collection Abrégé
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ISSN 0167-6369 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 1161
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Auteur Grzebyk, D.; Audic, S.; Lasserre, B.; Abadie, E.; de Vargas, C.; Bec, B.
Titre Insights into the harmful algal flora in northwestern Mediterranean coastal lagoons revealed by pyrosequencing metabarcodes of the 28S rRNA gene Type Article scientifique
Année 2017 Publication Revue Abrégée Harmful Algae
Volume 68 Numéro Pages 1-16
Mots-Clés Phytoplankton diversity; Harmful algae; Monitoring; alexandrium dinophyceae; dinoflagellate stoeckeria-changwonensis; domoic acid accumulation; eastern adriatic sea; Metabarcoding; partial lsu rdna; pfiesteria-piscicida dinophyceae; phylogenetic-relationships; pseudo-nitzschia bacillariophyceae; species complex dinophyceae; toxic dinoflagellate
Résumé This study investigated the genetic diversity of phytoplankton communities in six shallow lagoons located on the French coast of the northwestern Mediterranean Sea that represented a trophic gradient ranging from oligotrophic to hypereutrophic. The phytoplankton communities were sampled once a month from spring (May) to the beginning of autumn (September/early October) in 2012 and fractionated by size. Metabarcodes were generated from cDNAs by targeting the D1-D2 region of the 28S rRNA gene and pyrosequenced using Roche 454 technology. Examination of the annotated barcodes revealed harmful algal species not previously documented in these lagoons. Three ichthyotoxic species belonging to Pfiesteriaceae were detected: Luciella masanensis was relatively widespread and abundant in many samples, whereas Pfiesteria piscicida and Stoeckeria changwonensis were found as single barcode sequences. Furthermore, a phylogenetic analysis of barcodes annotated as belonging to Pfiesteriaceae suggested the existence of two previously undescribed clades. The other toxic or potentially harmful dinoflagellates detected through rare barcodes were Dinophysis acuminata, Vulcanodinium rugosum, Alexandrium andersonii and A. ostenfeldii. The two most abundant dinoflagellate taxa were Gymnodinium litoralis and Akashiwo sanguinea with respect to sequence numbers. Four diatom species from the genus Pseudo-nitzschia that potentially produce domoic acid were identified (P. galaxiae, P. delicatissima, P. brasiliana and P. calliantha). These observations are discussed in terms of the literature and monitoring records related to the identified taxa in this Mediterranean area. (C) 2017 Elsevier B.V. All rights reserved.
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Volume de collection Numéro de collection Edition
ISSN 1568-9883 ISBN Médium
Région Expédition Conférence
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Numéro d'Appel MARBEC @ alain.herve @ collection 2227
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Auteur Leblad, B.R.; Amnhir, R.; Reqia, S.; Sitel, F.; Daoudi, M.; Marhraoui, M.; Abdellah, M.K.O.; Veron, B.; Er-Raioui, H.; Laabir, M.
Titre Seasonal variations of phytoplankton assemblages in relation to environmental factors in Mediterranean coastal waters of Morocco, a focus on HABs species Type Article scientifique
Année 2020 Publication Revue Abrégée Harmful Algae
Volume 96 Numéro Pages 101819
Mots-Clés bay; bizerte lagoon; climate-change; domoic acid; Environmental factors; gymnodinium-catenatum; HABs; harmful algal blooms; Phytoplankton diversity; pseudo-nitzschia; psp toxins; shellfish; SW Mediterranean; temperature; Toxins
Résumé Studies on phytoplankton and in particular Harmful Algal Blooms (HABs) species in southern Mediterranean waters are scarce. We performed from April 2008 to June 2009 weekly investigations on microphytoplankton community structure and abundance in two contrasted marine ecosystems located in the western Moroccan Mediterranean coast, M'diq Bay and Oued Laou Estuary. Simultaneously, we measured the main physico-chemical parameters. Globally, the two studied areas showed comparable values of the assessed abiotic environmental factors. Temperature and salinity followed seasonal variation with values ranging from 13.5 degrees C to 21.4 degrees C and 31 to 36.8, respectively. Average nutrient values in surface water ranged from 0.7 to 45.76 mu M for dissolved inorganic nitrogen, 0.02-2.10 mu M for PO4 and 0.23-17.46 mu M for SiO4 in the study areas. A total of 92 taxa belonging to 8 taxonomic classes were found. The highest number of microphytoplankton abundance reached 1.2 x 10(6) cells L-1 with diatoms being the most abundant taxa. Factorial Discriminant Analysis (FDA) and Spearman correlation test showed a significant seasonal discrimination of dominant microphytoplankton species. These micro-organisms were associated with different environmental variables, in particular temperature and salinity. Numerous HABs species were encountered regularly along the year. Although Dinophysis species and Prorocentrum lima were present in both sites, no Lipophilic Shellfish Poisoning was detected for the analyzed bivalve mollusks. Domoic acid (DA), produced by toxic species of Pseudo-nitzschia was found with concentrations up to 18 mu g DA g(-1) in the smooth clam Callista chione. Data showed that the observed persistent and dramatic Paralytic Shellfish Poisoning (PSP) intoxication of mollusks resulted probably of Gymnodinium catenatum proliferations in both studied areas. Contrary to C. chione, the cockle Achanthocardia tuberculatum showed a permanent and extremely high toxicity level during the 15 months survey with up to 7545 mu g Equivalent Saxitoxin kg(-1) flesh (ten times higher than the sanitary threshold of 800 tg eqSTX Kg(-1) flesh). The present work highlights for the first time the dynamic of microphytoplankton including HABs species and their associated toxin accumulation in the commercially exploited shellfish in the southern western Mediterranean waters of Morocco. Furthermore, the acquired data will help us to improve the monitoring of HABs species and related toxins in these coastal marine systems.
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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 1568-9883 ISBN Médium
Région Expédition Conférence
Notes WOS:000541912700003 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2820
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Auteur Ramirez-Romero, E.; Molinero, J.C.; Sommer, U.; Salhi, N.; Yahia, O.K.-D.; Yahia, M.N.D.
Titre Phytoplankton size changes and diversity loss in the southwestern Mediterranean Sea in relation to long-term hydrographic variability Type Article scientifique
Année 2020 Publication Revue Abrégée Estuar. Coast. Shelf Sci.
Volume 235 Numéro Pages 106574
Mots-Clés bay; climate-change; Diversity loss; dynamics; evolution; jellyfish; marine; Nanophytoplankton; Ocean warming; patterns; Phytoplankton diversity; plankton communities; Size structural changes; Southwestern mediterranean; temperature; time-series
Résumé Structural changes in plankton primary producers have large implications for food web dynamics, energy fluxes and the vertical export of biogenic particulate carbon. Here we examine phytoplankton data spanning the period 1993-2008 from the Bay of Tunis, southwestern Mediterranean Sea, in relation to long term hydroclimate variability. We show a conspicuous shift in the structure of the phytoplankton community characterized by an increase of small-sized species and diversity loss, revealing a dominance of smaller blooming diatoms and cyanobacteria. Such changes were concurrent with marked modifications in hydroclimatic patterns experienced in the Bay of Tunis consisting of a shift towards enhanced winter precipitation together with rising temperatures. This novel study shows an overall rise in the proportion of small phytoplankton cells and a decreasing trend in phytoplankton diversity in the southern Mediterranean area. These findings warn of a potential decline of trophic efficiency and lesser food web stability resulting from mean size reduction and the diversity loss.
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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 0272-7714 ISBN Médium
Région Expédition Conférence
Notes WOS:000527915700034 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2766
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