Browsing by Author "Wallenstein, Francisco"
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- Accumulation of metals in Fucus spiralis subject to increased temperature and acidity.Publication . Wallenstein, Francisco; Torrão, Daniel F.; Neto, Ana I.; Wilkinson, Martin; Rodrigues, Armindo
- Algae based biotopes of the Azores (Portugal): spatial and seasonal variation.Publication . Wallenstein, Francisco; Neto, Ana I.; Álvaro, Nuno V.
- Algae-based biotopes of the Azores (Portugal): spatial and seasonal variation.Publication . Wallenstein, Francisco; Neto, Ana I.; Álvaro, Nuno V.; Santos, Catarina I.The increasing importance of coastal management created the need for a systematic classification and characterization of marine communities. Accurate quantitative methodologies for rocky shore algae-based biotope definition, were developed and tested on the Islands of São Miguel and Santa Maria (Azores). Shores of both islands were surveyed, covering all rocky substrate types. Biotopes were defined by assessing the associated habitat and species characteristics, using ANOSIM and SIMPER analysis, respectively. A total of ten biotopes were identified. Generally both islands’ biotopes are characterized by the same taxa/ecological categories, in summer and in winter. However, association between these taxa/ecological categories and the shore height at which they occur differs geographically and temporally. There is a generalized gradual succession of taxa/ecological categories from upper intertidal down to deepest subtidal, although geographical differences occur. Diversity is highest at the land–water interface and decreases towards both extremes (upper intertidal and deepest subtidal level). The strongest evidence of seasonal variation occurs at the upper intertidal. The methodology used proves to be effective in broad scale shoreline assessment of biological communities in warm-temperate coastal marine environments, and thus suitable for the purpose it was developed for. As a consequence it should be applied to the remaining islands of the Azorean archipelago as well as to other macaronesian islands, e.g. Madeira and the Canaries.
- The algal flora of the Azores: a historical and biogeographical approach.Publication . Terra, Marlene R.; Wallenstein, Francisco; Nogueira, Eunice M.; Neto, Ana I.; Tittley, Ian
- Azorean Coastal Communities. An On-going Study.Publication . Álvaro, Nuno V.; Wallenstein, Francisco; Neto, Ana I.; Nogueira, Eunice M.; Terra, Marlene R.
- Baseline metal concentrations in marine algae from São Miguel (Azores) under different ecological conditions – Urban proximity and shallow water hydrothermal activity.Publication . Wallenstein, Francisco; Couto, Ruben P.; Amaral, André; Wilkinson, Martin; Neto, Ana I.; Rodrigues, Armindo"[...]. The aim of this study was to provide baseline levels of a selected pool of elements for intertidal algae that occur abundantly on rocky shores around São Miguel Island (Azores), and compare results from non-urban sites with those affected by urban development or by shallow water hydrothermal activity. Coastal shallow water hydrothermally active sites are not common around the Globe. Consequently, information on macroalgal communities occurring in such specific environments provides a valuable tool for future research, not only to compare with sites that are artificially enriched with heavy metals (polluted), but also to assess the impact of increased temperature and acidity on such communities. [...]"
- Bioavailable metals and cellular effects in the digestive gland of marine limpets living close to shallow water hydrothermal vents.Publication . Cunha, Luís; Amaral, André; Medeiros, Vera; Martins, Gustavo M.; Wallenstein, Francisco; Couto, Ruben P.; Neto, Ana I.; Rodrigues, ArmindoThe pressure exerted by shallow water hydrothermal vents on edible gastropods and their cellular responses triggered by these stresses are almost unknown. The aims of this study were to evaluate the bioavailability of metals in the Macaronesian endemic limpet Patella candei gomesii living close to shallow water hydrothermal vents, and the structural differences in their digestive gland as well as the levels of apoptosis in that organ. Limpets were sampled in four sites, two with the presence of hydrothermalism and the other two without it. Whole body concentrations of several metals (Ca, Cd, Cs, Co, Cu, Fe, Hg, Mg, Mn, Pb, Rb, Se, Sr, and Zn) were obtained, morphometry analysis of the digestive gland and TUNEL test for apoptosis were also performed. Results revealed that the presence of shallow water hydrothermal vents is a source of chronic metal stress to limpets, imposing modifications in the morphometry and cell composition of the digestive gland of those limpets that may constitute cell and tissue adaptations to the environment they live in. This study sets up new baseline data for further research on the influence of shallow water hydrothermal vents over communities living in these habitats.
- Biótopos intertidais da Ilha de São Miguel – Açores.Publication . Wallenstein, Francisco; Couto, Ruben P.; Neto, Ana I.; Azevedo, José M. N.; Madeira, Patrícia
- Characterization of subtidal benthic communities in the Azores – a numerical approach – methodologies for oceanic islands.Publication . Wallenstein, Francisco; Neto, Ana I.; Álvaro, Nuno V.
- Coastal Biotopes of the Azores: a re-evaluation of the Marine Protected Areas.Publication . Neto, Ana I.; Wallenstein, Francisco; Álvaro, Nuno V.; Silva, Tito; Terra, Marlene R.