4 research outputs found
La sostenibilidad en la formación inicial del profesorado : aplicación del modelo ACES
Sobre la formació del professorat aplicant el model ACE
Comunidades faunÃsticas de un hábitat sublitoral de arena gruesa en el Mediterráneo Noroccidental
8 pages, 4 figures, 2 tables[EN] The sublittoral megabenthic assemblages of a northwestern Mediterranean coarse sandy beach exploited for the bivalve Callista chione were studied. The spatial and bathymetric variability of its distinctive faunal assemblages was characterised by quantitative sampling performed with a clam dredge. The taxa studied were Mollusca Bivalvia and Gastropoda, Crustacea Decapoda, Echinodermata and Pisces, which accounted for over 99% of the total biomass. Three well-differentiated species assemblages were identified: (1) assemblage MSS (Medium Sand Shallow) in medium sand (D50=0.37 mm) and shallow waters (mean depth =6.5 m), (2) assemblage CSS (Coarse Sand Shallow) in coarse sand (D50=0.62 mm) in shallow waters (mean depth =6.7 m), and (3) assemblage CSD (Coarse Sand Deep) in coarse sand (D50=0.64 mm) in deeper waters (mean depth =16.2 m). Assemblage MSS was characterised by the codominance of the bivalves Mactra stultorum and Acanthocardia tuberculata. C. chione was dominant in both density and biomass in assemblages CSS and CSD. The occurrence of the crab Thia scutellata also characterised assemblage CSS, whereas the occurrence of the sea urchin Echinocardium mediterraneum characterised assemblage CSD. A depth breaking point of around 10 m determined the discontinuity between assemblages CSS and CSD, which was related to the closure depth of the beaches in the study area. Species richness was highest in the coarse sand communities; however, Shannon-Wiener diversity and Pielou equitability indexes were higher in the shallow fine sand community[ES] Se han estudiado las comunidades megabentónicas sublitorales de playas de arena gruesa afectadas por la pesquerÃa del bivalvo Callista chione en el Mediterráneo noroccidental (Maresme). Se ha caracterizado la variabilidad espacial y batimétrica de las comunidades faunÃsticas presentes mediante un muestreo cuantitativo utilizando un rastrillo de bivalvos. Los taxones estudiados fueron Mollusca Bivalvia y Gastropoda, Crustacea Decapoda, Echinodermata y Pisces, los cuales representaron más del 99% de la biomasa total. Se identificaron tres comunidades bien diferenciadas: (1) comunidad MSS en arenas medias (D50=0.37 mm) y poco profundas (profundidad media =6.5 m), (2) comunidad CSS en arena gruesa (D50=0.62 mm) en aguas someras (6.7 m), y (3) comunidad CSD en arenas gruesas (D50=0.64 mm) en aguas más profundas (16.2 m). La comunidad MSS se caracterizó por la codominancia de los bivalvos Mactra stultorum y Acanthocardia tuberculata. C. chione dominó en densidad y biomasa en las comunidades CSS y CSD. La presencia del braquiuro Thia scutellata también caracterizó la comunidad CSS, mientras que la presencia del erizo Echinocardium mediterraneum caracterizó la comunidad CSD. Se detectó una discontinuidad entre las comunidades CSS y CSD a una profundidad de unos 10 m, la cual está relacionada con la profundidad de cierre de las playas del área de estudio. La riqueza especÃfica fue mayor en las comunidades de arena gruesa, no obstante los Ãndices de diversidad de Shannon-Wiener y de equitabilidad fueron superiores en la comunidad de arenas finasThis paper is a result of the research project "Avaluació de l'estat del banc natural de petxina lluenta del Maresme" funded by the Departament d'Agricultura, Ramaderia i Pesca - Generalitat de Catalunya. PA and MR are part of the research group 2009_SGR_1364 of the Generalitat de CatalunyaPeer reviewe
La desaparició de la petxina lluent: sobreexplotació o canvi ambiental
2 pages, 3 photographyPeer Reviewe
Retinoid and lipid patterns in the blubber of common dolphins (Delphinus delphis): implications for monitoring vitamin A status
We determined retinoid concentrations in various body positions of the blubber of 25 common dolphins (Delphinus delphis) to study topographical variation in concentrations. Specimens were obtained from incidental catches and were apparently healthy. We found concentrations to be high and therefore conclude that blubber represents a significant contribution to total retinoid body load. Consequently, blubber is proposed as a tissue of choice for monitoring retinoid status in this species. Anterior-ventral blubber had the highest vitamin A concentration and posterior-dorsal the lowest. Therefore, when assessing retinoid status, topographical variation should be taken into account to ensure consistent sampling. This pattern appeared to be explained by a parallel variation in lipid content. Thus, the dynamics and body distribution of retinoids appear to be basically governed by the lipophilicity of the molecules. The highest lipid richness found in the anterior-ventral region might indicate that this region is comparatively more important for insulation and lipid storage than the dorsal posterior region. Retinoid levels did not appear to vary according to sex, but they did vary with lipid content. This should be taken into account when designing sampling protocols; for monitoring purposes, biopsies from healthy, free-ranging individuals should be preferred to samples from stranded animals