A potentially toxic epiphytic dinoflagellate assemblage on macroalgae was studied for 1 yr in a shallow protected rocky habitat in Palamós (Costa Brava, NW Mediterranean). The assemblage was monitored on 4 macroalgae: Corallina elongata (Rhodophyceae), Dictyota dichotoma, Dilophus fasciola and Halopteris scoparia (Phaeophyceae). The dominant dinoflagellates were Ostreopsis sp., and the accompanying species were Coolia monotis and Prorocentrum lima. The diatom Coscinodiscus sp. was an abundant component of the assemblage. Ostreopsis followed the same seasonal pattern on the 4 macroalgae selected. Substrate was not significantly different for the dinoflagellate assemblages. Ostreopsis was present both in the water column and in the sand concomitant with maximal cell densities on macroalgae. Small-scale sampling revealed that all the epiphytic organisms prefer slightly shaken habitats. While Ostreopsis sp. prefers shaken to slightly shaken waters, Coolia monotis prefers slightly shaken to calm ones. The dinoflagellate assemblage follows a clear seasonal pattern, achieving maximum cell concentration during spring and summer without significant relative changes in the species composition. The epiphytic assemblage was widespread along the Catalan coast and Majorca, although dinoflagellates were found to be more abundant in the Costa Brava. In Corsica, diatoms dominated the assemblage, whereas Ostreopsis sp. was a minor component. KEY WORDS: Ostreopsis · Coolia monotis · Prorocentrum lima · Benthic dinoflagellates · Ciguatera fish poisoningResale or republication not permitted without written consent of the publisher Aquat Microb Ecol 26: 51-60, 2001 between sites (Tindall & Morton 1998). The mixed association of toxic dinoflagellates may contribute to the polymorphism of the clinical features of ciguatera (Yasumoto et al. 1987).Ostreopsidaceae species are widespread in most epiphytic and benthic dinoflagellate communities from ciguatera-endemic regions of the world (35°N to 35°S). Thus, the geographic distribution of Ostreopsis siamensis, O. lenticularis and O. ovata is similar to that of Gambierdiscus toxicus (Tindall & Morton 1998), with 2 notable exceptions: O. siamensis and O. ovata have been reported in the Mediterranean Sea (Taylor 1979, Tognetto et al. 1995. Nevertheless, data are limited on the incidence of Ostreopsis in the waters of the Mediterranean Sea and on the magnitude of potentially toxic epiphytic dinoflagellate assemblage attached to macroalgae.In this study, we quantified epiphytic dinoflagellate assemblages on the Catalan coast, NW Mediterranean. The potentially toxic epiphytic dinoflagellate assemblage associated with macroalgae was examined during an annual cycle in a rocky habitat. In addition, small-scale spatial variability and middle-scale spatial distribution were analysed to shed some light on the epiphytic dinoflagellate assemblages in the NW Mediterranean.The dominant dinoflagellate Ostreopsis sp. could not be assigned to any described species. Thus, a brief description of t...

The marine dinoflagellate genus Alexandrium includes a number of species which produce neurotoxins responsible for paralytic shellfish poisoning (PSP), which in humans may cause muscular paralysis, neurological symptoms, and, in extreme cases, death. A. minutum is the most widespread toxic PSP species in the western Mediterranean basin. The monitoring of coastal waters for the presence of harmful algae also normally involves microscopic examinations of phytoplankton populations. These procedures are time consuming and require a great deal of taxonomic experience, thus limiting the number of specimens that can be analyzed. Because of the genetic diversity of different genera and species, molecular tools may also help to detect the presence of target microorganisms in marine field samples. In this study, we developed a real-time PCR-based assay for rapid detection of all toxic species of the Alexandrium genus in both fixative-preserved environmental samples and cultures. Moreover, we developed a real-time quantitative PCR assay for the quantification of A. minutum cells in seawater samples. Alexandrium genus-specific primers were designed on the 5.8S rDNA region. Primer specificity was confirmed by using BLAST and by amplification of a representative sample of the DNA of other dinoflagellates and diatoms. Using a standard curve constructed with a plasmid containing the ITS1-5.8S-ITS2 A. minutum sequence and cultured A. minutum cells, we determined the absolute number of 5.8S rDNA copies per cell. Consequently, after quantification of 5.8S rDNA copies in samples containing A. minutum cells, we were also able to estimate the number of cells. Several fixed A. minutum bloom sea samples from Arenys Harbor (Catalan Coast, Spain) were analyzed using this method, and quantification results were compared with standard microscopy counting methods. The two methods gave comparable results, confirming that real-time PCR could be a valid, fast alternative procedure for the detection and quantification of target phytoplankton species during coastal water monitoring.

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. Emphasis is placed on integrated approaches that account for physico-chemical and biological components, and combine both pelagic and benthic symptoms of eutrophication, in keeping with the holistic nature of the MSFD. We highlight general features that any marine eutrophication model should possess, rather than making specific recommendations. European seas range from highly eutrophic systems such as the Baltic to nutrient-poor environments such as the Aegean Sea. From a Highlights ► Eutrophication guidance for the EU Marine Strategy Framework Directive (MSFD). ► Operational, management-oriented definition of eutrophication. ► Integrated assessment of physico-chemical and biological components. ► Assessment models combine both pelagic and benthic symptoms of eutrophication. ► Innovative approaches required for meaningful monitoring and assessment.