Browsing by Author "Wilkinson, Martin"
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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
- 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. [...]"
- Combining two multimetric indices for the assessment of water quality using seaweeds over a wide latitudinal gradientPublication . Wallenstein, Francisco; Neto, Ana I.; Rodrigues, Armindo; Wilkinson, Martin
- Effect of exposure time on the bioaccumulation of Cd, Mg, Mn and Zn in Cystoseira abies-marina samples subject to shallow water hydrothermal activity in São Miguel (Azores)Publication . Wallenstein, Francisco; Torrão, Daniel F.; Neto, Ana I.; Wilkinson, Martin; Rodrigues, ArmindoShallow water hydrothermal vents can be compared to polluted places due to high concentrations of heavy metals, and are thus good models for bioaccumulation studies. The present study intended to estimate the time of exposure required for the accumulation of certain elements to stabilize in specimens of Cystoseira abies-marina, to be used as a reference in future work. Cystoseira abies-marina intertidal specimens were transplanted from Mosteiros (a nonhydrothermal and pristine site) to Ferraria (with hydrothermal activity) and left there. Transplanted samples were collected after 1, 2, 4 and 8 weeks and the concentrations of Cd, Mg, Mn and Zn were measured through flame atomic absorption spectrophotometry. Although further studies with increased periods of exposure are needed because the concentration of these elements never stabilized in the collected samples, there is strong evidence that increased time of exposure led to increased concentrations of Cd, Mg, Mn, but not Zn. These results are consistent with the assumption that C. abies-marina is bioaccumulating some of the heavy metals and can thus be a good indicator for polluted waters.
- Effect of exposure time on the bioaccumulation of Cd, Mg, Mn and Zn in Cystoseira abies-marina samples subject to shallow water hydrothermal activity in São Miguel (Azores).Publication . Torrão, Daniel F.; Wallenstein, Francisco; Neto, Ana I.; Wilkinson, Martin; Rodrigues, Armindo
- An index based on seaweed communities to monitor coastal ecological quality in Macaronesia.Publication . Wallenstein, Francisco; Neto, Ana I.; Patarra, Rita F.; Prestes, Afonso L.; Álvaro, Nuno V.; Rodrigues, Armindo; Wilkinson, Martin
- Indices to monitor coastal ecological quality of rocky shores based on seaweed communities : simplification for wide geographical usePublication . Wallenstein, Francisco; Neto, Ana I.; Patarra, Rita F.; Prestes, Afonso L.; Álvaro, Nuno V.; Rodrigues, Armindo; Wilkinson, MartinEste estudo centra-se em características de comunidades de macroalgas do intertidal rochoso para avaliação da qualidade ecológica das massas de águas costeiras no âmbito da Diretiva-Quadro da Água (DQA). É proposto um índice alternativo aos desenvolvidos nas Ilhas Britânicas, no norte da Espanha e em Portugal continental, que resulta da comparação da aplicação de todos os índices a um conjunto de dados recolhidos em praias açorianas, discutindo-se a adequação dos parâmetros utilizados em cada índice. Os parâmetros incluídos no índice proposto foram selecionados de forma a permitir a sua aplicação numa área geográfica alargada.
- Intertidal rocky shore seaweed communities subject to the influence of shallow water hydrothermal activity in São Miguel (Azores, Portugal)Publication . Wallenstein, Francisco; Couto, Ruben P.; Torrão, Daniel F.; Neto, Ana I.; Rodrigues, Armindo; Wilkinson, MartinThe volcanic origin of the Azores archipelago (Portugal) gives rise to active deep sea and shallow water hydrothermal activity that affects benthic communities. Intertidal seaweed surveys were conducted at two shores affected by intense shallow water hydrothermal vents. Water temperature, acidity and salinity were monitored. Seaweed communities were found to be species poor and have a disproportionally larger number of filamentous early successional species on shores that are subject to the effect of hot and acidic freshwater of volcanic origin. There is an ecological resemblance between hydrothermally affected seaweed communities in the Azores and those affected by acid mine drainage in the UK, thus indicating that hydrothermalism can be a useful scenario for pollution studies under conditions of ocean warming and acidification.
- Intertidal Seaweed Communities Compared between Azores and Britain – Lessons for Water Framework Directive Monitoring.Publication . Wallenstein, Francisco; Neto, Ana I.; Rodrigues, Armindo; Wilkinson, Martin
- Rocky shore macroalgae communities of the Azores (Portugal) and the British Isles: a comparison for the development of ecological quality assessment toolsPublication . Wallenstein, Francisco; Neto, Ana I.; Rodrigues, Armindo; Wilkinson, Martin