28 research outputs found

    Análise de redes da paisagem submarina de canhão : implicações para o planeamento e gestão da biodiversidade

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    Submarine canyons are complex and heterogeneous geomorphologic structures highly relevant for the biodiversity and productivity of continental margins. These marine ecosystems play a key role providing invaluable goods and services for human well-being but are also increasingly subjected to the effects of anthropogenic pressure and climate change. The natural isolation of canyons may act synergistically with these changes with implications for population connectivity and the maintenance of biodiversity. The understanding of the causes and ecological consequences of such changes requires holistic and interdisciplinary approaches. I mapped the landscape of submarine canyon research based on a comprehensive bibliographic data set and using data mining techniques and network analysis. The existing knowledge clusters, historical trends, emergent topics and knowledge gaps in canyon research were identified and characterized. Topics such as “Geology & Geophysics”, “Oceanographic Processes” and “Biology & Ecology” were among the most studied while, for instance, “Biogeochemistry” and ecological modelling were among the less explored. Topics regarding anthropogenic impacts and climate-driven processes were only detected on publication of the last decade. The knowledge network reflects a latent interdisciplinarity in canyon research that developed mostly in the new millennium, supported by a well implemented and international collaboration network. The research efforts have been mainly directed towards only a few canyon systems and a thematic bias was identified, with specific topics addressed preferentially in particular canyons. This spatial and thematic bias, together with the paucity of truly inter-disciplinary studies, may be the most important limitation to the integrated knowledge and development of canyon research and hinders a global, more comprehensive understanding of canyon patterns and processes. The scientific landscape mapping and the complementary results are made available online as an open and interactive platform. In order to assess the importance of submarine canyons for the conservation and management on the deep sea, a study area and a modelling species were selected: the Mediterranean Sea and Lophelia pertusa, a cold-water coral species. The Mediterranean Sea encompasses several submarine canyon systems and L. pertusa is an ecosystem engineering species that occurs frequently in these geomorphological features and provides refuge, nursery grounds and physical support for a remarkable diversity of other life forms. Considering that the distribution of L. pertusa in the Mediterranean Sea is probably underestimated and that this information is crucial to assess the relevance of canyons in the Mediterranean seascape, I estimated the habitat suitability and draw uncertainty maps for this region based on environmental predictors and an ensemble approach of three machine-learning algorithms. The results suggest that in the Mediterranean Sea, L. pertusa encounters environmental settings close to its physiological limits but, despite the highly variable quality of the seascape, submarine canyons were identified as high suitability areas, especially across the Western and Central Mediterranean margins. In addition to the environmental suitability, the ecosystem connectivity determines the species distribution, the metapopulation dynamics and population resilience. I simulated the transport of L. pertusa larvae in the Mediterranean Sea using a biophysical model to estimate their potential dispersal as well as a network analysis to evaluate the habitat availability based on parameters such as suitability, spatial configuration of the seascape and the oceanographic conditions variability. The results suggest that connectivity among Mediterranean ecoregions is weak and that the intensification of climate-driven events (e.g., dense shelf water cascading) may worsen this scenario. However, the potential exchange of larvae between colonies within the same ecoregion was significant, favoring population resilience to local disturbances. Habitat areas with high quality and larval flux were identified as a priority for the conservation of L. pertusa, and subsequently also for their associated fauna. Once again, I showed that habitat areas on submarine canyons may play an important role in the connectivity of L. pertusa Mediterranean populations. However, these habitat areas are subjected to intense anthropogenic pressures, which allied to the effects of climate change, may impose greater challenges to their conservation. Apart from three French marine protected areas in the Gulf of Lion, the development of conservation efforts considering submarine canyon in the Mediterranean Sea is negligible. The knowledge produced in this thesis provides scientific evidence to support decision-making in conservation and planning of marine protected areas networks in the Mediterranean Sea and illustrates the relevance of submarine canyon for the management and conservation of deep-sea biodiversity.Os canhões submarinos são estruturas geomorfológicas complexas localizadas nas margens continentais. São reconhecidos como zonas importantes de biodiversidade no mar profundo onde os níveis de produtividade biológica são de modo geral superiores às áreas adjacentes. Estes ecossistemas marinhos desempenham um papel fundamental na prestação de bens e serviços essenciais ao bem-estar humano. Não obstante, estes ecossistemas estão cada vez mais sujeitos a efeitos nefastos que advêm de ações diretas das atividades humanas, mas também, resultantes de alterações climáticas. O isolamento natural dos canhões submarinos em conjunto com estas mudanças, pode ter implicações para a conectividade das populações biológicas que os habitam, bem como para a manutenção da biodiversidade associada. Avaliar as causas e efeitos ecológicos de tais mudanças só será possível através de uma abordagem holística e interdisciplinar. Partindo de uma base de dados bibliográfica abrangente de publicações dedicadas ao estudo de canhões submarinos, usei técnicas de data mining e de análise de redes para mapear o conhecimento reunido até agora. Foram identificados clusters de conhecimento, a evolução histórica da investigação em canhões submarinos, bem como, os tópicos emergentes e lacunas no conhecimento sobre estas estruturas. Os tópicos mais desenvolvidos dizem respeito a áreas associadas à “Geologia e Geofísica”, “Processos Oceanográficos” e “Biologia e Ecologia”. Por outro lado, temas como “Biogeoquímica” e modelação ecológica estão entre os menos explorados. Estudos referentes a impactos antropogénicos nestes ecossistemas e alterações induzidas por processos climáticos foram detetados apenas em publicação datadas da última década. A rede de tópicos gerada reflete uma interdisciplinaridade latente na investigação associada a canhões que se desenvolveu principalmente durante o século XXI, apoiada por colaborações internacionais da comunidade científica. No entanto, a investigação científica em canhões submarinos apresenta uma tendência clara direccionada para determinados temas e áreas geográficas. Tópicos específicos são abordados preferencialmente em determinados canhões, enquanto que um número muito pequeno destas estruturas concentra a maior parte dos trabalhos desenvolvidos. Este resultado juntamente com o número reduzido de estudos interdisciplinares, foi a mais importante limitação detetada que poderá dificultar a integração do conhecimento já reunido sobre estas estruturas, impedido uma compreensão mais abrangente dos padrões e processos associados aos canhões submarinos. Os resultados alcançados foram disponibilizados numa plataforma online aberta para exploração interativa e direcionada dos conteúdos. No sentido de avaliar a importância dos canhões para a conservação e gestão da biodiversidade no mar profundo, foi definida como área de estudo o Mar Mediterrâneo e selecionada como espécie modelo, um coral de água fria: Lophelia pertusa. O Mar Mediterrâneo engloba vários sistemas de canhões submarinos enquanto que L. pertusa é uma espécie engenheira de ecossistemas que cria refúgio, áreas de berçário e habitat para uma panóplia de outras espécies, ocorrendo frequentemente em canhões. Uma vez que a distribuição de L. pertusa no Mar Mediterrâneo está provavelmente subestimada e que esta informação é fundamental para avaliar a relevância dos canhões na área de estudo, desenvolvi um modelo de nicho ecológico baseado em variáveis ambientais e uma abordagem conjunta de três algoritmos. Os resultados obtidos foram mapas de adequação ambiental, bem como, de avaliação da capacidade de previsão do modelo. Os resultados sugerem que no mar Mediterrâneo, esta espécie de coral encontra condições ambientais próximas dos seus limites fisiológicos. Apesar disso, áreas com condições favoráveis à ocorrência de L. pertusa foram detetadas em canhões submarinos, principalmente no Mediterrâneo Ocidental e Central. A par da qualidade dos habitats, a distribuição dos organismos, a dinâmica metapopulacional e a resiliência das populações a perturbações estão fortemente relacionadas com a conectividade dos ecossistemas. Neste contexto, simulei o transporte de larvas de L. pertusa no Mar Mediterrâneo usando um modelo biofísico para estimar o seu potencial de dispersão. Com os resultados do modelo e usando análises de rede, avaliei a disponibilidade de habitat com base em parâmetros como a qualidade, configuração espacial da paisagem marinha e variabilidade oceanográfica. Os resultados sugerem que a conectividade entre as eco-regiões do Mar Mediterrâneo é baixa e que a intensificação de eventos impulsionados por condições climáticas (por exemplo, dense shelf water cascading) pode agravar este cenário. No entanto, a potencial troca de larvas entre colónias dentro da mesma eco-região foi significativa, podendo favorecer a resiliência das populações a perturbações locais. Áreas de habitat com boa qualidade e com fluxo de larvas foram identificadas como prioritárias para a conservação de L. pertusa, com benefícios eventuais também para a fauna associada a este coral. Mais uma vez, áreas de habitat incluídas em canhões submarinos foram identificadas como as mais relevantes no Mar Mediterrâneo, devendo desempenhar um papel importante na conectividade de populações desta espécie. Contudo, estas áreas estão igualmente sujeitas de forma intensa a atividades humanas com efeitos prejudiciais nos ecossistemas, e que, aliadas aos efeitos das alterações climáticas, podem dificultar a implementação de medidas de conservação eficazes. Com a exceção de três áreas marinhas protegidas francesas no Golfo do Leão, o desenvolvimento de esforços de conservação no Mar Mediterrâneo que incluam áreas com canhões submarinos é ainda negligenciável. Os resultados apresentados nesta tese fornecem evidências científicas que poderão apoiar medidas de conservação e gestão com vista à criação de redes de áreas marinhas protegidas no Mar Mediterrâneo. Neste sentido, proponho os canhões submarinos como áreas prioritárias para a conservação da biodiversidade de mar profundo na área de estudo.PEst-C/MAR/LA0017/2013 e UID/AMB/50017/2013Programa Doutoral em Biologia e Ecologia das Alterações Globai

    How Much Longer Will it Take? A Ten-year Review of the Implementation of United Nations General Assembly Resolutions 61/105, 64/72 and 66/68 on the Management of Bottom Fisheries in Areas Beyond National Jurisdiction

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    The United Nations General Assembly (UNGA) in 2002 adopted the first in a series of resolutions regarding the conservation of biodiversity in the deep sea. Prompted by seriousconcerns raised by scientists, non-governmental organizations (NGOs) and numerous States,these resolutions progressively committed States to act both individually and through regional fishery management organizations (RFMOs) to either manage bottom fisheries in areas beyond national jurisdiction to prevent significant adverse impacts on deep-sea species, ecosystems and biodiversity or else prohibit bottom fishing from taking place.Ten years have passed since the adoption of resolution 61/105 in 2006, calling on States to take a set of specific actions to manage bottom fisheries in areas beyond national jurisdiction to protect vulnerable marine ecosystems (VMEs) from the adverse impacts of bottom fishing and ensure the sustainability of deep-sea fish stocks. Despite the considerable progress by some RFMOs, there remain significant gaps in the implementation of key elements and commitments in the resolutions. The Deep Sea Conservation Coalition (DSCC) has prepared this report to assist the UNGA in its review in 2016 and to address the following question: How effectively have the resolutions been implemented

    Elucidation of etiology of colorectal cancer: A study on silencing of p16 gene by promoter hypermethylation

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    Colorectal cancer (CRC), commonly known as bowel cancer is the third most common cause of cancer-related deaths in the western world. Colorectal cancer is one of the leading malignancies worldwide. CRC has been reported to show geographical variation in its incidence, even within areas of ethnic homogeneity. The usual treatment is surgery and subsequent chemotherapy and radiotherapy. Cancer development and progression is dictated by series of alterations in genes such as tumor suppressor genes, DNA repair genes, oncogenes and others. In colorectal carcinogenesis disturbances different from mutations called an epigenetic regulation are also taken into consideration. The aim of this study was to study the promoter hypermethylation of CpG islands of p16 gene in colorectal cancer patients among the Kashmiri population. The study included 70 surgically obtained colorectal samples among which 50 were obtained from colorectal cancer patients and 20 were histopathologically normal colorectal samples. All the samples were histopathologically confirmed before further processing. DNA was extracted from all the samples and was modified using bisulphite modification kit. Methylation-specific polymerase (MSP) chain reaction was used for analysis of the promoter hypermethylation status of p16 gene. The genetic analysis of the cases and controls by MSP- PCR method, for checking the promoter hypermethylation of CpG islands of p16 gene revealed that unlike other high risk regions, Kashmiri population has a different promoter hypermethylation profile of p16 gene. 66% of the cases showed p16 promoter hypermethylation while as 34% of the cases were nonhypermethylated. The study also revealed that 20% of the normal cases also had promoter hypermethylation of p16 gene and 80% did not showed promoter hypermethylation of p16 gene. The association of promoter hypermethylation with colorectal cancer was evaluated by χ2 (Chi square) test with Odds ratio and was found to be significant. Among 29 male cases and 21 female cases, the association of promoter hypermethylation with colorectal cancer was evaluated using Fisher’s exact test and was found to be significant in both males and females. Occurrence of p16 promoter hypermethylation was found to be unequally distributed in males and females with more frequency in males than in females but the difference was not statistically significant. When the frequency of p16 promoter hypermethylation was compared with clinical staging of the disease, p16 promoter hypermethylation was found to be certainly higher in Stage III/IV (83.33%) compared to Stage I/ II (56.25%) but the difference was not statistically significant. Also, the degree of p16 promoter hypermethylation increased with the increasing severity of the lesion but the difference was not again statistically significant. These results clearly suggest that p16 aberrant promoter hypermethylation in Kashmiri population contributes to the process of carcinogenesis in colorectal cancer and is reportedly one of the commonest epigenetic changes in the development of human CRC. It also demonstrates that hypermethylation of p16 gene can be designated as epigenetic biomarker for the screening, diagnosis and prognosis of colorectal cancer. The data gives a clue that p16 gene expression can be readily and fully restored and growth rate of cancer cells decreased by treatment of cancer cells with demethylating agents and DNA methylation inhibitors

    Oceanography

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    How inappropriate to call this planet Earth when it is quite clearly Ocean (Arthur C. Clarke). Life has been originated in the oceans, human health and activities depend from the oceans and the world life is modulated by marine and oceanic processes. From the micro-scale, like coastal processes, to macro-scale, the oceans, the seas and the marine life, play the main role to maintain the earth equilibrium, both from a physical and a chemical point of view. Since ancient times, the world's oceans discovery has brought to humanity development and wealth of knowledge, the metaphors of Ulysses and Jason, represent the cultural growth gained through the explorations and discoveries. The modern oceanographic research represents one of the last frontier of the knowledge of our planet, it depends on the oceans exploration and so it is strictly connected to the development of new technologies. Furthermore, other scientific and social disciplines can provide many fundamental inputs to complete the description of the entire ocean ecosystem. Such multidisciplinary approach will lead us to understand the better way to preserve our "Blue Planet": the Earth
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