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Auteur Ben Gharbia, H.; Laabir, M.; Ben Mhamed, A.; Gueroun, S.K.M.; Yahia, M.N.D.; Nouri, H.; M'Rabet, C.; Shili, A.; Yahia, O.K.-D.
Titre Occurrence of epibenthic dinoflagellates in relation to biotic substrates and to environmental factors in Southern Mediterranean (Bizerte Bay and Lagoon, Tunisia): An emphasis on the harmful Ostreopsis spp., Prorocentrum lima and Coolia monotis Type Article scientifique
Année 2019 Publication (up) Revue Abrégée Harmful Algae
Volume 90 Numéro Pages 101704
Mots-Clés algal blooms; allelopathic interactions; cf. ovata blooms; coastal waters; Environmental factors; Epibenthic dinoflagellates; genus ostreopsis; Macrophytes; posidonia-oceanica; recently-deposited sediment; seasonal-changes; ships ballast water; Southern Mediterranean; toxin production
Résumé Harmful events associated with epibenthic dinoflagellates, have been reported more frequently over the last decades. Occurrence of potentially toxic benthic dinoflagellates, on the leaves of two magnoliophytes (Cymodocea nodosa and Zostera noltei) and thalli of the macroalgae (Ulva rigida), was monitored over one year (From May 2015 to April 2016) in the Bizerte Bay and Lagoon (North of Tunisia, Southern Mediterranean Sea). The investigated lagoon is known to be highly anthropized. This is the first report on the seasonal distribution of epibenthic dinoflagellates hosted by natural substrates, from two contrasted, adjacent coastal Mediterranean ecosystems. The environmental factors promoting the development of the harmful epibenthic dinoflagellates Ostreopsis spp., Prorocentrum lima and Coolia monotis were investigated. The highest cell densities were reached by Ostreopsis spp. (1.9 x 10(3) cells g(-1) FW, in October 2015), P. lima (1.6 x 10(3) cells g(-1) FW, in June 2015) and C. monotis (1.1 x 10(3) cells g(-1) FW, in May 2015). C. nodosa and Z. noltei were the most favorable host macrophytes for C. monotis (in station L2) and Ostreopsis spp. (in station L3), respectively. Positive correlations were recorded between Ostreopsis spp. and temperature. Densities of the epibenthic dinoflagellates varied according to the collection site, and a great disparity was observed between the Bay and the Lagoon. Maximum concentrations were recorded on C. nodosa leaves from the Bizerte Bay, while low epiphytic cell abundances were associated with macrophytes sampled from the Bizerte Lagoon. The observed differences in dinoflagellate abundances between the two ecosystems (Bay-Lagoon) seemed not related to the nutrients, but rather to the poor environmental conditions in the lagoon.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 1568-9883 ISBN Médium
Région Expédition Conférence
Notes WOS:000502893700004 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2695
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Auteur Ben-Gharbia, H.; Yahia, O.K.-D.; Amzil, Z.; Chomerat, N.; Abadie, E.; Masseret, E.; Sibat, M.; Triki, H.Z.; Nouri, H.; Laabir, M.
Titre Toxicity and Growth Assessments of Three Thermophilic Benthic Dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) Developing in the Southern Mediterranean Basin Type Article scientifique
Année 2016 Publication (up) Revue Abrégée Toxins
Volume 8 Numéro 10 Pages 297
Mots-Clés coastal waters; Coolia monotis; environmental-factors; growth; gulf-of-california; harmful algal blooms; marine dinoflagellate; multiple sequence alignment; new-zealand; okadaic acid; Ostreopsis cf. ovata; Prorocentrum lima; Southern Mediterranean Sea; sp-nov dinophyceae; toxicity; toxin profile
Résumé Harmful benthic dinoflagellates, usually developing in tropical areas, are expanding to temperate ecosystems facing water warming. Reports on harmful benthic species are particularly scarce in the Southern Mediterranean Sea. For the first time, three thermophilic benthic dinoflagellates (Ostreopsis cf. ovata, Prorocentrum lima and Coolia monotis) were isolated from Bizerte Bay (Tunisia, Mediterranean) and monoclonal cultures established. The ribotyping confirmed the morphological identification of the three species. Maximum growth rates were 0.59 +/- 0.08 d(-1) for O. cf. ovata, 0.35 +/- 0.01 d(-1) for C. monotis and 0.33 +/- 0.04 d(-1) for P. lima. Toxin analyses revealed the presence of ovatoxin-a and ovatoxin-b in O. cf. ovata cells. Okadaic acid and dinophysistoxin-1 were detected in P. lima cultures. For C. monotis, a chromatographic peak at 5.6 min with a mass m/z = 1061.768 was observed, but did not correspond to a mono-sulfated analogue of the yessotoxin. A comparison of the toxicity and growth characteristics of these dinoflagellates, distributed worldwide, is proposed.
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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 2072-6651 ISBN Médium
Région Expédition Conférence
Notes Approuvé pas de
Numéro d'Appel MARBEC @ alain.herve @ collection 1690
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Auteur Basset, A.; Barbone, E.; Elliott, M.; Li, B.-L.; Jorgensen, S.E.; Lucena-Moya, P.; Pardo, I.; Mouillot, D.
Titre A unifying approach to understanding transitional waters: Fundamental properties emerging from ecotone ecosystems Type Article scientifique
Année 2013 Publication (up) Revue Abrégée Estuarine Coastal and Shelf Science
Volume Numéro Pages
Mots-Clés climate change; ecotone concept; landscape ecology; transitional waters
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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 433
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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.
Titre 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 (up) 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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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 2325-1026 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2276
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Auteur Draredja, M.A.; Frihi, H.; Boualleg, C.; Abadie, E.; Laabir, M.
Titre Distribution of dinoflagellate cyst assemblages in recent sediments from a southern Mediterranean lagoon (Mellah, Algeria) with emphasis on toxic species Type Article scientifique
Année 2020 Publication (up) Revue Abrégée Environ. Sci. Pollut. Res.
Volume Numéro Pages
Mots-Clés alexandrium-catenella; bizerte lagoon; coastal waters; cochlodinium-polykrikoides; Dinoflagellate cysts; Diversity; Environmental factors; genus alexandrium; harmful algal blooms; Mellah lagoon; northwestern indian-ocean; resting cysts; Spatial distribution; spatial-distribution; surface sediments; Toxic species
Résumé This is the first study on the dinoflagellate cysts in Algerian waters and in Mellah Lagoon (South Western Mediterranean), located within a protected reserve. In total, 42 species of dinocysts belonging to 7 orders, 12 families and 23 genera, were identified in the 26 superficial sediment samples from Mellah Lagoon. The distribution of dinocysts in the sediment of this lagoon is heterogeneous. Indeed, their abundance oscillates between 1 and 315 cysts g(-1) dry sediment (DS). Cyst morphotype assemblages were dominated by a few numbers of species: Alexandrium minutum (15.87%), Gonyaulax verior (9.81%), Protoperidinium spp. (7.74%), Alexandrium affine (7.05%), Scrippsiella trochoidea (6.67%), and Alexandrium pseudogonyaulax (6.19%). There is a positive correlation between the density of cysts and the depth (r = 0.61; p < 0.05), organic matter (r = 0.70; p < 0.05), water content (r = 0.71; p < 0.05), and the fine fraction of sediment (r = 0.74; p < 0.05). Surprisingly, although the Mellah Lagoon is almost semi-closed, it holds an important specific richness in dinocysts (42 species) higher than others observed in Mediterranean lagoons. However, cyst abundances are low compared to other lagoons in the Mediterranean Sea. Finally, the presence of dinocysts of Alexandrium catenella/tamarense, A. minutum, and Gymnodinium catenatum associated to paralytic shellfish toxins, A. pseudogonyaulax which produces goniodomin A, also Protoceratium reticulatum and Gonyaulax spinifera complex which produce yessotoxins, needs to implement a monitoring program to prevent a potential human intoxication due to the consumption of contaminated sea products by these potent neurotoxins.
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Langue English Langue du Résumé Titre Original
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Volume de collection Numéro de collection Edition
ISSN 0944-1344 ISBN Médium
Région Expédition Conférence
Notes WOS:000529493300024 Approuvé pas de
Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2796
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