Browsing by Author "Couto, Ruben P."
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- Algas coralinas nos Açores : um mundo a descobrirPublication . Couto, Ruben P.[…]. Vários estudos sobre a composição algal dos Açores continuam a adicionar/identificar novas espécies para a flora dos Açores. Estes estudos mostram que as nossas ilhas, isoladas no Atlântico, suportam uma flora algal marinha relativamente rica, chamando a atenção de cientistas de vários países, desde há muito tempo. Um dos grupos de algas, ainda relativamente pouco estudados nos Açores são as algas calcárias ou algas coralinas. São chamadas assim devido à sua estrutura em Carbonato de Cálcio (calcário) que lhes dá uma superfície rija e resistente, que representa entra 70 a 90% do seu peso depois de secas. Estão entre as algas mais conspícuas dos Açores, consideradas espécies de crescimento lento, mas, uma vez estabelecidas, geralmente persistem por longos períodos de tempo e, por esse motivo, são mais abundantes em substratos fixos (e.g. escoadas lávicas) junto ao nível da agua do mar, ocupando em alguns locais mais de 90% do espaço. […].
- 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
- Choreonema thuretii and Pneophyllum confervicola (Corallinales, Rhodophyta), new records of coralline algae for the AzoresPublication . Couto, Ruben P.; Alquicira, Edgar; Rodrigues, Armindo; Neto, Ana I.Choreonema thuretii and Pneophyllum confervicola, two cosmopolitan species, are here recorded for the first time for the Azores. They were found during an investigation of intertidal communities in Pico Island (Azores) in the summer of 2007. Both species were found hosted in Jania rubens specimens, C. thuretii as a semi-endophytic parasite, P. confervicola as an epiphyte. They are present on other archipelagos from Macaronesia (Madeira and Canary Islands). It is likely that they have been overlooked in the Azores due to their small size and parasitic/epiphytic habit. A morphological and anatomical account is provided for both species, and it is hoped that this additional observations provided herein will alert field surveyors for their presence.
- Choreonema thuretii and Pneophyllum confervicolum (Corallinales, Rhodophyta), new corallines to the Azores.Publication . Couto, Ruben P.; Rosas-Alquicira, Edgar; Rodrigues, Armindo; Neto, Ana I.
- Coralline algae, structuring organisms of warm temperate intertidal communities.Publication . Couto, Ruben P.; Rodrigues, Armindo; Neto, Ana I.
- Crabs tell the difference : relating trace metal content with land use and landscape attributesPublication . Álvaro, Nuno V.; Neto, Ana I.; Couto, Ruben P.; Azevedo, José M. N.; Rodrigues, ArmindoHeavy metal concentration in a given locality depends upon its natural characteristics and level of anthropogenic pressure. Volcanic sites have a different heavy metal footprint from agriculture soils and both differ from urban centres. Different animal species absorb heavy metals differently according to their feeding behaviour and physiology. Depending on the capability to accumulate heavy metals, some species can be used in biomonitoring programs for the identification of disturbed areas. Crabs are included in these species and known to accumulate heavy metals. The present study investigates the potential of Pachygrapsus marmoratus (Fabricius, 1787), a small crab abundant in the Azores intertidal, as an indicator of the presence of heavy metals in Azorean coastal environments, comparing hydrothermal vent locations, urban centres and locations adjacent to agricultural activity. Specimens were collected in the same period and had their hepatopancreas removed, dried and analysed for heavy metals. Results revealed differences in concentration of the studied elements between all sampling sites, each one revealing a distinct heavy metal content. Fe, Cu, Mn, Zn and Cd are the metals responsible for separating the various sites. The concentration levels of the heavy metals recorded in the present study reflect the environmental available metals where the organisms live. This, associated to the large availability of P. marmoratus specimens in the Azores, and to the fact that these animals are easy to capture and handle, suggests this species as a potential bioindicator for heavy metal concentration in Azorean coastal areas, both humanized and naturally disturbed.
- Ervilia castanea (Mollusca, Bivalvia) populations adversely affected at CO₂ seeps in the North AtlanticPublication . Martins, Marta; Silva, Marina Carreiro; Martins, Gustavo M.; Ramos, Joana B.; Viveiros, Fátima; Couto, Ruben P.; Parra, Hugo; Monteiro, João; Gallo, Francesca; Silva, Catarina; Teodósio, Alexandra; Guilini, Katja; Hall-Spencer, Jason M.; Leitão, Francisco; Chícharo, Luís; Range, PedroSites with naturally high CO₂ conditions provide unique opportunities to forecast the vulnerability of coastal ecosystems to ocean acidification, by studying the biological responses and potential adaptations to this increased environmental variability. In this study, we investigated the bivalve Ervilia castanea in coastal sandy sediments at reference sites and at volcanic CO₂ seeps off the Azores, where the pH of bottom waters ranged from average oceanic levels of 8.2, along gradients, down to 6.81, in carbonated seawater at the seeps. The bivalve population structure changed markedly at the seeps. Large individuals became less abundant as seawater CO₂ levels rose and were completely absent from the most acidified sites. In contrast, small bivalves were most abundant at the CO₂ seeps. We propose that larvae can settle and initially live in high abundances under elevated CO₂ levels, but that high rates of post-settlement dispersal and/or mortality occur. Ervilia castanea were susceptible to elevated CO₂ levels and these effects were consistently associated with lower food supplies. This raises concerns about the effects of ocean acidification on the brood stock of this species and other bivalve molluscs with similar life history traits.
- Fontes hidrotermais : laboratórios naturais de acidificação oceânicaPublication . Couto, Ruben P.[…]. Em 2010 foi desenvolvido um estudo na Universidade dos Açores sobre os efeitos das fontes hidrotermais de superfície na composição química, anatomia e estrutura calcária de Corallina elongata, uma alga calcária abundante nos Açores. Este trabalho, publicado na “Marine Pollution Bulletin”, revelou que, apesar da acidez nas fontes hidrotermais, e contrariamente ao esperado, as algas, embora mostrando sinais externos de alguma dissolução, apresentavam paredes celulares mais espessas, ou seja, com maior deposição de Carbonato de Cálcio. O gás libertado pelas fontes hidrotermais (CO₂), para além de acidificar a água do mar, também é um elemento fulcral na obtenção de energia pelas algas e pelas outras plantas através da fotossíntese. Ora, a maior disponibilidade de CO₂ potencia o metabolismo da alga fazendo com que esta tenha uma maior taxa de crescimento, contrariamente ao que era inicialmente esperado. […]
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