987 resultados para Arrecifes de coral


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Coral reefs are globally threatened by climate change-related ocean warming and ocean acidification (OA). To date, slow-response mechanisms such as genetic adaptation have been considered the major determinant of coral reef persistence, with little consideration of rapid-response acclimatization mechanisms. These rapid mechanisms such as parental effects that can contribute to trans-generational acclimatization (e.g. epigenetics) have, however, been identified as important contributors to offspring response in other systems. We present the first evidence of parental effects in a cross-generational exposure to temperature and OA in reef-building corals. Here, we exposed adults to high (28.9°C, 805 µatm PCO2) or ambient (26.5°C, 417 µatm PCO2) temperature and OA treatments during the larval brooding period. Exposure to high treatment negatively affected adult performance, but their larvae exhibited size differences and metabolic acclimation when subsequently re-exposed, unlike larvae from parents exposed to ambient conditions. Understanding the innate capacity corals possess to respond to current and future climatic conditions is essential to reef protection and maintenance. Our results identify that parental effects may have an important role through (1) ameliorating the effects of stress through preconditioning and adaptive plasticity, and/or (2) amplifying the negative parental response through latent effects on future life stages. Whether the consequences of parental effects and the potential for trans-generational acclimatization are beneficial or maladaptive, our work identifies a critical need to expand currently proposed climate change outcomes for corals to further assess rapid response mechanisms that include non-genetic inheritance through parental contributions and classical epigenetic mechanisms.

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Cold-water corals, such as Lophelia pertusa, are key habitat-forming organisms found throughout the world's oceans to 3000 m deep. The complex three-dimensional framework made by these vulnerable marine ecosystems support high biodiversity and commercially important species. Given their importance, a key question is how both the living and the dead framework will fare under projected climate change. Here, we demonstrate that over 12 months L. pertusa can physiologically acclimate to increased CO2, showing sustained net calcification. However, their new skeletal structure changes and exhibits decreased crystallographic and molecular-scale bonding organization. Although physiological acclimatization was evident, we also demonstrate that there is a negative correlation between increasing CO2 levels and breaking strength of exposed framework (approx. 20-30% weaker after 12 months), meaning the exposed bases of reefs will be less effective 'load-bearers', and will become more susceptible to bioerosion and mechanical damage by 2100.

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Ocean acidification has the potential to cause dramatic changes in marine ecosystems. Larval damselfish exposed to concentrations of CO2 predicted to occur in the mid- to late-century show maladaptive responses to predator cues. However, there is considerable variation both within and between species in CO2 effects, whereby some individuals are unaffected at particular CO2 concentrations while others show maladaptive responses to predator odour. Our goal was to test whether learning via chemical or visual information would be impaired by ocean acidification and ultimately, whether learning can mitigate the effects of ocean acidification by restoring the appropriate responses of prey to predators. Using two highly efficient and widespread mechanisms for predator learning, we compared the behaviour of pre-settlement damselfish Pomacentrus amboinensis that were exposed to 440 µatm CO2 (current day levels) or 850 µatm CO2, a concentration predicted to occur in the ocean before the end of this century. We found that, regardless of the method of learning, damselfish exposed to elevated CO2 failed to learn to respond appropriately to a common predator, the dottyback, Pseudochromis fuscus. To determine whether the lack of response was due to a failure in learning or rather a short-term shift in trade-offs preventing the fish from displaying overt antipredator responses, we conditioned 440 or 700 µatm-CO2 fish to learn to recognize a dottyback as a predator using injured conspecific cues, as in Experiment 1. When tested one day post-conditioning, CO2 exposed fish failed to respond to predator odour. When tested 5 days post-conditioning, CO2 exposed fish still failed to show an antipredator response to the dottyback odour, despite the fact that both control and CO2-treated fish responded to a general risk cue (injured conspecific cues). These results indicate that exposure to CO2 may alter the cognitive ability of juvenile fish and render learning ineffective.

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Número 238 en el catálogo de Vicente Galbis e Hilari García

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Nesta pesquisa desenvolvemos um estudo focado na convivência conflituosa entre a música tradicional e a música contemporânea. Foi desenvolvida em um grupo religioso protestante específico, intuindo investigar a hipótese de que há uma tensão entre a prática do Canto Coral e as novas tendências musicais representadas pelas Bandas. Como procedimento metodológico utilizamos uma pesquisa de campo que avaliou a realidade musical em algumas Igrejas Batistas de Campinas. A partir dos resultados obtidos sugerimos ações concretas à práxis pastoral. O primeiro capítulo propõe uma retrospectiva conceitual e histórica do Canto Coral, avaliando sua função antes e depois do processo da reforma e da nova mentalidade musical desenvolvida por Lutero. O segundo capítulo mostra o desenvolvimento da pesquisa realizada junto a seis Igrejas Batistas. Tenta mensurar o gosto musical dos membros dessas comunidades através de um estudo comparativo a partir dos dois pólos: Canto Coral e Banda, ambos, sendo o específico de um campo maior: Tradição e Contemporâneo. O terceiro capítulo, partindo dos impulsos obtidos, desenvolve uma visão crítica sobre os aspectos da tradição, da aceitação à novas tendências, e da tensão propriamente desenvolvida na convivência entre estilos musicais distintos. Mediante tal realidade conflituosa, apresentamos um desafio à práxis pastoral no sentido de se obter possibilidades para uma convivência musical pacífica, considerando a inserção de elementos da contemporaneidade e da tradição na liturgia Batista.

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Nesta pesquisa desenvolvemos um estudo focado na convivência conflituosa entre a música tradicional e a música contemporânea. Foi desenvolvida em um grupo religioso protestante específico, intuindo investigar a hipótese de que há uma tensão entre a prática do Canto Coral e as novas tendências musicais representadas pelas Bandas. Como procedimento metodológico utilizamos uma pesquisa de campo que avaliou a realidade musical em algumas Igrejas Batistas de Campinas. A partir dos resultados obtidos sugerimos ações concretas à práxis pastoral. O primeiro capítulo propõe uma retrospectiva conceitual e histórica do Canto Coral, avaliando sua função antes e depois do processo da reforma e da nova mentalidade musical desenvolvida por Lutero. O segundo capítulo mostra o desenvolvimento da pesquisa realizada junto a seis Igrejas Batistas. Tenta mensurar o gosto musical dos membros dessas comunidades através de um estudo comparativo a partir dos dois pólos: Canto Coral e Banda, ambos, sendo o específico de um campo maior: Tradição e Contemporâneo. O terceiro capítulo, partindo dos impulsos obtidos, desenvolve uma visão crítica sobre os aspectos da tradição, da aceitação à novas tendências, e da tensão propriamente desenvolvida na convivência entre estilos musicais distintos. Mediante tal realidade conflituosa, apresentamos um desafio à práxis pastoral no sentido de se obter possibilidades para uma convivência musical pacífica, considerando a inserção de elementos da contemporaneidade e da tradição na liturgia Batista.

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The integrin family of cell surface receptors is strongly conserved in higher animals, but the evolutionary history of integrins is obscure. We have identified and sequenced cDNAs encoding integrin β subunits from a coral (phylum Cnidaria) and a sponge (Porifera), indicating that these proteins existed in the earliest stages of metazoan evolution. The coral βCn1 and, especially, the sponge βPo1 sequences are the most divergent of the “β1-class” integrins and share a number of features not found in any other vertebrate or invertebrate integrins. Perhaps the greatest difference from other β subunits is found in the third and fourth repeats of the cysteine-rich stalk, where the generally conserved spacings between cysteines are highly variable, but not similar, in βCn1 and βPo1. Alternatively spliced cDNAs, containing a stop codon about midway through the full-length translated sequence, were isolated from the sponge library. These cDNAs appear to define a boundary between functional domains, as they would encode a protein that includes the globular ligand-binding head but would be missing the stalk, transmembrane, and cytoplasmic domains. These and other sequence comparisons with vertebrate integrins are discussed with respect to models of integrin structure and function.

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Acknowledgements The authors acknowledge L. Wicks and B. de Francisco for helping in coral sampling and coral care in the aquaria facilities at SAMS. Thanks to C. Campbell and the CCAP for kind support and help. Scientific party and crew on board the RVs Calanus and Seol Mara, as well as on board the RRS James Cook during the Changing Oceans cruise (JC_073) are greatly acknowledged. Thanks to colleagues at SAMS for their support during our stay at SAMS. We are in debt with A. Olariaga for his help modifying the cylindrical experimental chambers used in the experiments, and C.C. Suckling for assistance with the flume experiment. Many thanks go to G. Kazadinis for preparing the POM used in the feeding experiments. We also thank two anonymous reviewers and the editor for their constructive comments, which contribute to improve the manuscript. This work has been supported by the European Commission through two ASSEMBLE projects (grant agreement no. 227799) conducted in 2010 and 2011 at SAMS, as well as by the UK Ocean Acidification Research Programme's Benthic Consortium project (awards NE/H01747X/1 and NE/H017305/1) funded by NERC. [SS]