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| Madhupratap, M; Sawant, S; Gauns, M. |
| A thick bloom of the marine prymnesiophycean, Phaeocystis globosa was observed in the central Arabian Sea during the summer monsoon period (July-August, 1996). The cells were mostly in colonial form, embedded in gelatinous matrices. The cell diameter was approximately 7 mu m and showed a distinct double feature form. The intensity of the bloom was as high as 3750 x 10(6) cells m(-2) and the carbon content ranged between 33 and 550 mu g L(-1). Almost 90% of the phytoplankton population was composed of P. globosa in the bloom area. Other common forms were chain-forming diatoms like Rhizosolenia spp., Nitzschia spp. and Chaetoreros spp. The photosynthetic pigment chlorophyll a, however did not show any concomitant rise with the bloom intensity probably... |
| Tipo: Text |
Palavras-chave: Prymnesiophycée; Phaeocystis; Floraison; Mer d’Arabie; Prymnesiophyceae; Phaeocystis; Bloom; Arabian sea. |
| Ano: 2000 |
URL: http://archimer.ifremer.fr/doc/00325/43579/44047.pdf |
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| Lefebvre, Alain; Delpech, Jean-paul. |
| Dans le contexte des blooms récurrents de la prymnésiophycée Phaeocystis sp .en Manche orientale, une enquête a été mise en oeuvre en 2003 afin d’appréhender les conséquences socio-économiques et/ou écologiques de ce phénomène auprès des conchyliculteurs et des professionnels de la pêche. Plusieurs centaines de questionnaires ont été mis en circulation et une campagne d’information (radio, télévision, presse, internet) a été engagée lors de la période de prédilection de Phaeocystis (mars à juin). Les réponses furent peu nombreuses et bien que certaines gênes pour la pratique de leurs activités peuvent être signalées, le phénomène semble faire partie du « paysage local » et n’inquiète pas particulièrement les professionnels de la mer. |
| Tipo: Text |
Palavras-chave: Bloom; Phaeocystis; Manche orientale; Conchyliculteurs; Pêcheurs; Nuisances. |
| Ano: 2004 |
URL: http://archimer.ifremer.fr/doc/00326/43756/43300.pdf |
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| Menesguen, Alain; Aminot, Alain; Belin, Catherine; Chapelle, Annie; Guillaud, Jean-francois; Joanny, Michel; Lefebvre, Alain; Merceron, Michel; Piriou, Jean-yves; Souchu, Philippe. |
| In order to be able to count the cases of coastal eutrophication and to propose methods to monitor as well as to reduce these phenomena, first of all it is necessary to precisely define the word eutrophication itself. Instead of the strict etymological definition, that is to say a progression of the enrichment of a medium, we will rather retain the concept of a state enriched at a point such as it causes harmful effects on the ecosystem, and nuisances to man's activities. Based on the average chemical equations of the organic matter synthesis/degradation in the sea, this operational definition thus puts forwards the harmful consequences of enrichment, i.e. the production of an excessive algal biomass, sometimes unbalanced from the point of view of... |
| Tipo: Text |
Palavras-chave: Alexandrium; Phaeocystis; Monostroma; Ulva; Dilution plume; Water trapping; Anoxia; Nitrogen and phosphorus loadings; Red tides; Phytoplankton blooms; Green tides; Eutrophication; Alexandrium; Phaeocystis; Monostroma; Ulva; Panache de dilution; Confinement; Anoxie; Phosphate; Nitrate; Apports terrigènes; Eaux colorées; Blooms phytoplanctoniques; Marées vertes; Eutrophisation. |
| Ano: 2001 |
URL: http://archimer.ifremer.fr/doc/2001/rapport-22.pdf |
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| Poisson Caillault, Emilie; Lefebvre, Alain. |
| Marine water quality monitoring and subsequent management require to know when a specific event like harmful algae bloom may occur and which environmental conditions and pressures lead to this event. So, event detection and its dynamic understanding are crucial to adapt strategy. An algorithm is proposed to identify curves mixture and their dynamics features - initiation, duration, peaks and ends of the event. The approach is fully unsupervised, it requires no tuning parameters and is based on Expectation Maximization process to estimate the most robust mixture according to fixed criteria. A complete framework is proposed to deal with a univariate time series with missing data. The approach is applied on Chlorophyll- a series collected weekly since 1989.... |
| Tipo: Text |
Palavras-chave: Time series; Event detection; Expectation-Maximisation; Phenology; Chlorophyll-a; Phaeocystis. |
| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00435/54679/56097.pdf |
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