66 research outputs found

    Solos e Evolução da Paisagem em Ambiente Periglacial na Península Barton, Antártica Marítima

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    Antarctic soils are characterized by low development degree due to low liquid water content. Compared to mainland, Maritime Antactica has a mild climate. These milder conditions allow a much greater development of soils and more significant chemical weathering. The study area is Barton Peninsula, the second largest ice-free area of King George Island (Maritime Antarctica). The Barton Peninsula has soils derived from different lithologies, with basalt / andesite (with pyrite) standing out. This study aimed to evaluate the role of relief in the genesis of sulfated soils. Three pedons were selected, described, sampled, and classified according to Soil Taxonomy and WRB/FAO. Morphological, physical, mineralogical and chemical analysis were performed. The Barton soils present polygenic evolution. The rock shattering caused by freezing and thawing is present as a pedogenetic process. However, the evolution degree of the soils is substantially associated with the acidification by sulphide oxidation. This process promotes the release of elements, such as Fe, which are mobilized by the relief. Consequently, duricrusts (i.e. petroplintic horizons) are formed, characterizing a transformation of the pedological cover. The genesis of these soils shows that the peri-glacial landscape is dynamic and of deep interest in soil-geomorphological investigations.As baixas disponibilidade de água líquida e temperatura na Antártica condicionam a formação de solos incipientes. Condições climáticas menos severas na Antártica Marítima permitem o maior desenvolvimento de solos, com maior cobertura vegetal e intemperismo químico mais significativo. A Península Barton, localizada na Ilha Rei George (Antártica Marítima), possui solos derivados de litologias diversas, com destaque para o basalto/andesito piritizado, representando a área de maior extensão de materias sulfídicos na região. O objetivo deste trabalho foi analisar o papel do relevo na gênese de solos sulfatados e sua relação com a evolução da paisagem. Os solos foram classificados de acordo com a Soil Taxonomy e WRB/FAO. Foram descritos três perfis em toposequência e analisados seus atributos morfológicos, físicos, químicos e mineralógicos. A crioclastia está presente como um processo pedogenético, mas o que se destaca é o grau evolutivo dos solos associado à acidificação pela oxidação dos sulfetos. Esse processo promove a liberação de elementos como o Fe, que são mobilizados por influência do relevo. Consequentemente, formam-se niveis encouraçados, isto é, horizontes petroplínticos, caracterizando uma transformação da cobertura pedológica. A gênese destes solos demonstra que a paisagem periglacial é dinâmica e de profundo interesse das investigações pedogeomorfológicas

    Desmantelamento da produção petrolífera: métodos de descomissionamento e captura de co2 / Decommissioning of petroleum production: decommissioning methods and co2 capture

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    O descomissionamento de uma plataforma offshore, que consiste na desativação e desinstalação das estruturas utilizadas para exploração de petróleo, é um processo delicado e, portanto, que requer métodos bem detalhados e delineados. Este trabalho apresenta e discute os principais métodos de descomissionamento offshore, tais como: remoção completa, remoção parcial e tombamento da plataforma. Além disso, este estudo aborda o uso alternativo para plataformas offshore atuais para quando a produção de hidrocarbonetos cessar. Discutimos em detalhes a possibilidade de captura e armazenamento de carbono (CCS), que pode trazer compensações ambientais. Concluímos que o descomissionamento de instalações da indústria de exploração e produção ainda é um grande desafio, principalmente no Brasil. Por isso, é necessário estabelecer procedimentos regulatórios e critérios adequados de execução, de forma a minimizar os riscos às pessoas e ao meio ambiente. A captura e armazenamento de carbono ainda enfrentam desafios em termos de custos e tecnologia, como a separação de CO2 e metano. No entanto, avanços recentes na pesquisa têm mostrado soluções viáveis para essas questões. 

    Wild dogs at stake: deforestation threatens the only Amazon endemic canid, the short-eared dog (Atelocynus microtis)

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    The persistent high deforestation rate and fragmentation of the Amazon forests are the main threats to their biodiversity. To anticipate and mitigate these threats, it is important to understand and predict how species respond to the rapidly changing landscape. The short-eared dog Atelocynus microtis is the only Amazon-endemic canid and one of the most understudied wild dogs worldwide. We investigated short-eared dog habitat associations on two spatial scales. First, we used the largest record database ever compiled for short-eared dogs in combination with species distribution models to map species habitat suitability, estimate its distribution range and predict shifts in species distribution in response to predicted deforestation across the entire Amazon (regional scale). Second, we used systematic camera trap surveys and occupancy models to investigate how forest cover and forest fragmentation affect the space use of this species in the Southern Brazilian Amazon (local scale). Species distribution models suggested that the short-eared dog potentially occurs over an extensive and continuous area, through most of the Amazon region south of the Amazon River. However, approximately 30% of the short-eared dog's current distribution is expected to be lost or suffer sharp declines in habitat suitability by 2027 (within three generations) due to forest loss. This proportion might reach 40% of the species distribution in unprotected areas and exceed 60% in some interfluves (i.e. portions of land separated by large rivers) of the Amazon basin. Our local-scale analysis indicated that the presence of forest positively affected short-eared dog space use, while the density of forest edges had a negative effect. Beyond shedding light on the ecology of the short-eared dog and refining its distribution range, our results stress that forest loss poses a serious threat to the conservation of the species in a short time frame. Hence, we propose a re-assessment of the short-eared dog's current IUCN Red List status (Near Threatened) based on findings presented here. Our study exemplifies how data can be integrated across sources and modelling procedures to improve our knowledge of relatively understudied species

    Characterization of Pictorial Materials of Two 18th Century Sculptures: King David and Bathsheba

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    In this {work}, the X-ray fluorescence technique was employed to characterize the pictorial materials used in two sculptures from the 18th. In addition, Raman spectroscopy was used to characterize the preparation layers used in the sculptures. {The analyzed sculptures} are carved in wood, with gilding and polychrome, and represent the biblical characters, Bathsheba, and King David. The sculptures are property of the Church of \textit{Nossa Senhora do Pilar}, in Duque de Caxias, RJ. XRF {analyzes} were performed using a portable ED-XRF system, which has a low-power X-ray tube (Amptek) with a silver target (Ag) and an SDD detector (Amptek). Raman spectroscopy {analyzes} were performed using the DXR2 Raman microscopy equipment (Thermo Fisher Scientific) with a 785 nm laser source. The results obtained from the XRF and Raman spectroscopy techniques suggest the presence of Gypsum, Calcite, Calcium Sulfate. In addition, the results obtained suggest the presence of the following pigments in the sculptures: Lead white, Titanium White, Lithopone, Ochre, Vermilion, Red Lead and gilding with gold leaf. The studies also showed that the Bathsheba sculpture was probably subjected to some processes of chromatic reintegration over the years due to the heterogeneity of pigments found in the same regio
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