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| Jauzein, Cecile; Loureiro, Sofia; Garces, Esther; Collos, Yves. |
| Short-term experiments were carried out to investigate whether interactions between ammonium (NH4+) and urea uptake regulate the total nitrogen assimilation of the toxic dinoflagellate Alexandrium catenella. To test for strain variability, 5 strains of A. catenella from the NW Mediterranean were used: 3 strains from the Thau lagoon (southern France) and 2 strains from the Catalonia basin (Spain). For each strain, the uptake rate of 1 nutrient (NH4+ or urea) at a reference concentration (10 mu gatN l(-1)) was measured as a function of the increasing concentration of the other nutrient (0 to 10 mu gatN l(-1)). Simultaneous N uptake rates of the distinct nitrogen sources were obtained from N-15-NH4+ and N-15-urea incorporation measurements. A strong... |
| Tipo: Text |
Palavras-chave: Strain variability; Interactions; Urea; Ammonium; Alexandrium catenella. |
| Ano: 2008 |
URL: http://archimer.ifremer.fr/doc/2008/publication-6432.pdf |
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| Loureiro, Sofia; Jauzein, Cecile; Garces, Esther; Collos, Yves; Camp, Jordi; Vaque, Dolors. |
| The influence of organic nutrients on the evolution of Pseudo-nitzschia delicatissima cultures was investigated in an enrichment experiment with high-molecular-weight dissolved organic matter (HMWDOM) and in an uptake assay with N-15-ammonium and N-15-urea. HMWDOM was extracted from seawater collected at a nearby shore station during the decline of a diatom bloom. Four incubations were prepared: L1/5+DOM (P. delicatissima grown in L1 growth medium with 1/5 of the nitrate concentration of standard L1), (L1-N)+DOM (L1 without nitrate, i.e. nitrogen-deficient treatment), L1-DOM (control culture without added DOM) and BV+DOM (bacterial and viral control, free of microalgae). Incubations were carried out for 10 days. Chlorophyll a concentrations differed after... |
| Tipo: Text |
Palavras-chave: Harmful Algal Blooms (HABs); Nitrogen Uptake; Urea; Dissolved Organic Matter (DOM). |
| Ano: 2009 |
URL: http://archimer.ifremer.fr/doc/2009/publication-6438.pdf |
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| Ferreira, Joao G.; Andersen, Jesper H.; Borja, Angel; Bricker, Suzanne B.; Camp, Jordi; Da Silva, Margarida Cardoso; Garces, Esther; Heiskanen, Anna-stiina; Humborg, Christoph; Ignatiades, Lydia; Lancelot, Christiane; Menesguen, Alain; Tett, Paul; Hoepffner, Nicolas; Claussen, Ulrich. |
| In 2009, following approval of the European Marine Strategy Framework Directive (MSFD, 2008/56/EC), the European Commission (EC) created task groups to develop guidance for eleven quality descriptors that form the basis for evaluating ecosystem function. The objective was to provide European countries with practical guidelines for implementing the MSFD, and to produce a Commission Decision that encapsulated key points of the work in a legal framework. This paper presents a review of work carried out by the eutrophication task group, and reports our main findings to the scientific community. On the basis of an operational, management-oriented definition, we discuss the main methodologies that could be used for coastal and marine eutrophication assessment.... |
| Tipo: Text |
Palavras-chave: Eutrophication; Chlorophyll; Dissolved oxygen; Harmful algae; Marine; Coastal; Assessment methods; Europe; Marine Strategy Framework Directive; Water Framework Directive. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00039/15055/12609.pdf |
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