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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.
Titre 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 (up) 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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Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1574-6941 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 444
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Auteur Hoang, H.T.T.; Duong, T.T.; Nguyen, K.T.; Le, Q.T.P.; Luu, M.T.N.; Trinh, D.A.; Le, A.H.; Ho, C.T.; Dang, K.D.; Némery, J.; Orange, D.; Klein, J.
Titre Impact of anthropogenic activities on water quality and plankton communities in the Day River (Red River Delta, Vietnam) Type Article scientifique
Année 2018 Publication (up) Revue Abrégée Environ Monit Assess
Volume 190 Numéro 2 Pages 67
Mots-Clés Water quality; Tropical; Vietnam; Day River; Plankton communities; Red River Delta
Résumé Planktons are a major component of food web structure in aquatic ecosystems. Their distribution and community structure are driven by the combination and interactions between physical, chemical, and biological factors within the environment. In the present study, water quality and the community structure of phytoplankton and zooplankton were monthly investigated from January to December 2015 at 11 sampling sites along the gradient course of the Day River (Red River Delta, northern Vietnam). The study demonstrated that the Day River was eutrophic with the average values of total phosphorus concentration 0.17 mg/L, total nitrogen concentration 1.98 mg/L, and Chl a 54 μg/L. Microscopic plankton analysis showed that phytoplankton comprised 87 species belonging to seven groups in which Chlorophyceae, Bacillariophyceae, and Cyanobacteria accounted for the most important constituents of the river's phytoplankton assemblage. A total 53 zooplankton species belonging to three main groups including Copepoda, Cladocera, and Rotatoria were identified. Plankton biomass values were greatest in rainy season (3002.10-3 cell/L for phytoplankton and 12.573 individuals/m3 for zooplankton). Using principal correspondence and Pearson correlation analyses, it was found that the Day River was divided into three main site groups based on water quality and characteristics of plankton community. Temperature and nutrients (total phosphorus and total nitrogen) are key factors regulating plankton abundance and distribution in the Day River.
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Langue eng Langue du Résumé Titre Original
Éditeur de collection Titre de collection Titre de collection Abrégé
Volume de collection Numéro de collection Edition
ISSN 1573-2959 ISBN Médium
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Numéro d'Appel MARBEC @ alain.herve @ collection 2263
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Auteur Hadjadji, I.; Masseret, E.; Plisson, B.; Laabir, M.; Cecchi, P.; Collos, Y.
Titre Clonal variation in physiological parameters of Alexandrium tamarense: implications for biological invasions and maintenance Type Article scientifique
Année 2012 Publication (up) Revue Abrégée Cah. Biol. Mar.
Volume 53 Numéro 3 Pages 357-363
Mots-Clés Alexandrium tamarense; Fitness; Growth rate; Humic acid; Intraspecific variability; Lag phase; blooms; catenella; complex dinophyceae; dinoflagellate; dinophyceae; growth; humic substances; marine-phytoplankton; southern france; thau lagoon; urea uptake
Résumé The study of the intraspecific variability is a crucial step for understanding the successful establishment and maintenance of invasive species. Alexandrium tamarense strains isolated in spring 2007 from a single bloom in Thau lagoon have been grown on three different media (ESNW based on natural seawater, and the artificial media, ESAW, ESAW+HA). A large diversity in the ability of strains to grow on these media was found. Irrespective of medium composition, growth curves followed three models: (1) a classical shape, (2) a population crash followed in some cases (3) by growth recovery. Some strains were able to show significant growth in an environment completely artificial (ESAW). ANOVA indicated a significant difference between groups in growth rates allowing the distinction of contrasted categories among the strains studied in ESNW medium. These statistical tests also indicated the presence of distinct groups among the strains grown in the ESAW as well as for those on ESAW+HA medium. Lag phases were extremely variable between strains in all environments, suggesting a high variability of adaptation to the environment. The results revealed that wide fitness variations were exhibited by diverse conspecific A. tamarense individuals co-existing during a bloom.
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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 0007-9723 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 473
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Auteur Williamson, P.; Wallace, D.W.R.; Law, C.S.; Boyd, P.W.; Collos, Y.; Croot, P.; Denman, K.; Riebesell, U.; Takeda, S.; Vivian, C.
Titre Ocean fertilization for geoengineering: A review of effectiveness, environmental impacts and emerging governance Type Article scientifique
Année 2012 Publication (up) Revue Abrégée Process Saf. Environ. Protect.
Volume 90 Numéro 6 Pages 475-488
Mots-Clés Geoengineering; Governance; Negative emission technologies; Ocean fertilization; Southern Ocean; atmospheric; carbon-dioxide; community response; diatom bloom; equatorial; iron; mesoscale iron enrichment; microbial response; pacific; perpetual salt fountain; phytoplankton bloom; southern-ocean; sub-arctic pacific
Résumé Dangerous climate change is best avoided by drastically and rapidly reducing greenhouse gas emissions. Nevertheless, geoengineering options are receiving attention on the basis that additional approaches may also be necessary. Here we review the state of knowledge on large-scale ocean fertilization by adding iron or other nutrients, either from external sources or via enhanced ocean mixing. On the basis of small-scale field experiments carried out to date and associated modelling, the maximum benefits of ocean fertilization as a negative emissions technique are likely to be modest in relation to anthropogenic climate forcing. Furthermore, it would be extremely challenging to quantify with acceptable accuracy the carbon removed from circulation on a long term basis, and to adequately monitor unintended impacts over large space and time-scales. These and other technical issues are particularly problematic for the region with greatest theoretical potential for the application of ocean fertilization, the Southern Ocean. Arrangements for the international governance of further field-based research on ocean fertilization are currently being developed, primarily under the London Convention/London Protocol. (C) 2012 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
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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 0957-5820 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 741
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Auteur Trombetta, T.; Vidussi, F.; Mas, S.; Parin, D.; Simier, M.; Mostajir, B.
Titre Water temperature drives phytoplankton blooms in coastal waters Type Article scientifique
Année 2019 Publication (up) Revue Abrégée Plos One
Volume 14 Numéro 4 Pages e0214933
Mots-Clés Artificial light; Biomass; Food web structure; Phytoplankton; Salinity; Spring; Surface water; Wind
Résumé Phytoplankton blooms are an important, widespread phenomenon in open oceans, coastal waters and freshwaters, supporting food webs and essential ecosystem services. Blooms are even more important in exploited coastal waters for maintaining high resource production. However, the environmental factors driving blooms in shallow productive coastal waters are still unclear, making it difficult to assess how environmental fluctuations influence bloom phenology and productivity. To gain insights into bloom phenology, Chl a fluorescence and meteorological and hydrological parameters were monitored at high-frequency (15 min) and nutrient concentrations and phytoplankton abundance and diversity, were monitored weekly in a typical Mediterranean shallow coastal system (Thau Lagoon). This study was carried out from winter to late spring in two successive years with different climatic conditions: 2014/2015 was typical, but the winter of 2015/2016 was the warmest on record. Rising water temperature was the main driver of phytoplankton blooms. However, blooms were sometimes correlated with winds and sometimes correlated with salinity, suggesting nutrients were supplied by water transport via winds, saltier seawater intake, rain and water flow events. This finding indicates the joint role of these factors in determining the success of phytoplankton blooms. Furthermore, interannual variability showed that winter water temperature was higher in 2016 than in 2015, resulting in lower phytoplankton biomass accumulation in the following spring. Moreover, the phytoplankton abundances and diversity also changed: cyanobacteria (< 1 μm), picoeukaryotes (< 1 μm) and nanoeukaryotes (3–6 μm) increased to the detriment of larger phytoplankton such as diatoms. Water temperature is a key factor affecting phytoplankton bloom dynamics in shallow productive coastal waters and could become crucial with future global warming by modifying bloom phenology and changing phytoplankton community structure, in turn affecting the entire food web and ecosystem services.
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Volume de collection Numéro de collection Edition
ISSN 1932-6203 ISBN Médium
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Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2565
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