Browsing by Author "Moura, Delminda"
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- Acreção da superfície das plataformas rochosas de sopé: Ribeira de Ilhas, Estremadura, PortugalPublication . Neves, Mário; Ramos-Pereira, Ana; Trindade, Jorge; Moura, Delminda; Gusmão, FranciscaA monitorização do rebaixamento de uma plataforma rochosa de sopé do litoral da Estremadura (Ribeira de Ilhas) forneceu um conjunto de resultados de acreção – crescimento em altura de um ponto da superfície rochosa medido anteriormente. A avaliação da evolução da plataforma foi efectuada utilizando um TMEM (Traversing Micro‐Erosion Meter) com capacidade máxima para monitorizar 255 pontos contidos numa área de 117 cm2, com uma precisão superior a 0,005mm. O período de estudo decorreu entre Setembro de 2008 e Março de 2010 com campanhas de medição efectuadas a cada dois meses.Determinaram‐se as características do substrato da plataforma rochosa de sopé da Ribeira de Ilhas, nomeadamente a litologia, estrutura, resistência à compressão e composição sedimentológica. Relativamente aos pontos que sofreram acreção, analisou‐se comparativamente a sua ocorrência nas duas áreas de monitorização em função da sua diferente exposição ao ar, bem como a possível ocorrência de padrões estacionais e identificaram‐se os processos com capacidade de justificar os valores registados.
- Algarve: a study case for global vs regional climatic changes in mid latitude estuaries during the HolocenePublication . Veiga-Pires, C.; Mestre, Nélia; Moura, Delminda; Luis, Joaquim; Boski, T.Located at the extreme southwestern end of the Iberian Peninsula, in the South of Portugal, the Algarve province is bordered to the north by the Alentejo province, to the east by the Guadiana River, and to the west and south by the Atlantic Ocean. Its coastal region can be divided into two different sectors: the eastern sector, which is mainly made of barrier island and lagoon system named the Ria Formosa, and the western sector mainly represented by clastic and carbonated cliffs. In each sector, we sampled long and short sedimentary cores (ca. 30m and 3m, respectively) in two different estuaries. Therefore, the different sedimentary records obtained from the four estuaries should permit to identify global vs. west-eastern regional climatic changes through the observation of several proxies. Two of these proxies are sediment color and magnetic susceptibility, which have been acquired every five centimeters along core depth, using the Colortron II spectrophotometer and SM-20 magneto-susceptometer, respectively. Sediment surfaces of short cores were also digitized using the Mustek 1200 A3 PRO Scanner. Furthermore, short cores have been sampled every five centimeters along depth in order to analyze the sediment for its major and minor elements content, its organic carbon content, and its granulometry and mineralogy. Some shell fragments have also been sampled and sent for radiocarbon radiometry or AMS dating, allowing therefore constructing some absolute chronologies for the several cores. Some relative chronologies based on digital color profiles are also being used in order to correlate sedimentary sequences between cores. All the cores are mainly composed of clay, with the existence of soil horizons at the top of the cores and frequent sand layers towards their base. Several element profiles along depths are compared, namely those regarding Sr, Ca, F, Ba, Al and Ti, as well as their ratios. First results indicate that geochemical and color data allow to identify similar sequences from west to east probably related to major climate episodes. Although, pronounced differences in mineralogy and accumulation rates from on site to another are probably due to differences, respectively, in the geochemistry of the drainage basin substratum and in the flow rate of the rivers, and therefore to local precipitation. We acknowledge FEDER and OE that financed this study through the Portuguese Foundation for Science and Technology (FCT) (POCTI/CTA/39733/2001).
- An attempt to develop spectrophotometry as a proxy for sedimentary studies in estuarine environmentsPublication . Veiga-Pires, C.; Mestre, Nélia; Moura, Delminda; Luis, Joaquim; Boski, T.In deep-sea sediment studies, reflectance has been used as a proxy for high vs. low productivity intervals for several years. This value of the white-black scale is obtained through the use of spectrophotometers when using the CIE Lab color system, which also gives values on green-red and blue-yellow scales. In estuarine/continental sediment studies, color data are still often based on Munsell Table which does not allow to obtain numeric and continuous data and which is biased by the observer’s choice.
- An attempt to use CIE Lab digital colour to study sediment profiles from the Alvor estuary, South PortugalPublication . Veiga-Pires, C.; Mestre, Nélia; Moura, Delminda; Martins, H.; Boski, T.The study of estuarine sedimentary records is of great interest for paleo-environmental and paleo-climatologic reconstructions, because they represent environments that are sensitive to sea level and climatic variations, and also because they are characterized high sedimentary rates. However, due to the price and time needed to analyze the geochemical composition of sediments, it is very difficult to obtain profiles with a high resolution needed toanswer present scientific problems. In the present work, we report results obtained by applying solid-state spectrophotometry on cores from the Alvor's estuary (Algarve), which allows acquiring almost continous, high resolution, digital colour profiles. CIE Labcolour data, obtained with a Colortron spectrophotometer in there cores, were to geochemical sediment characteristics using multivariate statistical analyses.(...)
- An open source geophysical software for studying speleothem growth bands and comparing with a reference curve: MironePublication . Veiga-Pires, C.; Coelho, Catarina; Moura, Delminda; Luis, JoaquimSpeleothem growth bands are commonly referred as one of the parameters that are used for paleoclimate reconstructions. Accordingly, this work presents a new tool for detecting these bands based on the gray-scale image of the speleothem using the Mirone open source geophysical software. This program has initially been developed for working on georeferenciated images for geophysical studies, as for instance for recognizing paleomagnetic inversions from deep-sea sediments. This recognition based on gridded images is very similar to what is needed for the recognition and detection of speleothem growth bands.
- Aplicação do modelo SWAN na caracterização da agitação marítima: Praia da GaléPublication . Reis, Rui; Fortes, Conceição; Gabriel, Selma; Moura, DelmindaNo âmbito do projeto EROS - Erosão dos Litorais Rochosos – Diferenças Na Proteção Conferida Pelas Praias Arenosas e Pelas Formas Litorais, projeto PTDC/CTE-GIX/111230/2009 financiado pela Fundação para a Ciência e Tecnologia, efetuou-se a caraterização da agitação marítima na zona da praia da Galé, recorrendo ao modelo numérico SWAN (Booij et al. 1999). Esta caraterização é efetuada em duas partes: 1 – Aplicação e validação do modelo SWAN para as condições de agitação marítima que se verificaram no período 6 a 12 de Março 2012 que corresponde ao período em que se efetuaram medições in situ na praia da Galé; 2 – Aplicação do modelo SWAN para as condições de agitação marítima no período de 1998 a 2007 o que permite a caracterização do regime observado e médio da zona em estudo. O presente relatório descreve este trabalho. Assim depois desta introdução efectua-se no capítulo 2, a descrição do modelo SWAN, no capítulo 3 a aplicação e validação do modelo SWAN e a caracterização dos regimes observado e médio. O relatório termina com o capítulo de conclusões.
- Aplicação multimédia sobre a Ria Formosa e seus fins educacionais (ForDid)Publication . Oliveira, Sónia; Boski, T.; Moura, Delminda; Mendes da Silva de Sousa, Carlos A; Gomes, Ana; Pereira, LauraNa atualidade torna-se inquestionável a necessidade de integrar a aprendizagem com as novas tecnologias de modo a cativar e facilitar a compreensão dos temas abordados através de aplicações didáticas. Durante a última década o Centro de Investigação Marinha e Ambiental (CIMA) assumiu a responsabilidade de criar meios eficazes de comunicação entre o público em geral e a comunidade científica, através de plataformas multimédia interativas. Foram objecto destas aplicações didáticas as várias vertentes do património natural do Algarve. Após o sucesso das primeiras aplicações GuaDid e MonDid visando o Estuário do Rio Guadiana e a Serra de Monchique respectivamente, o desafio de criar e inovar foi acrescido, resultando numa nova aplicação – ForDid, visando a divulgação do importante sistema lagunar Ria Formosa.
- Aquaculture in the crossroad of microplastic contaminationPublication . Bebianno, Maria; Manthopoulos, Michael; Nathan, Justine; Cristina, Sónia; Ribeiro, Laura; Luna-Araújo, Ravi; Icely, John; Dias Duarte Fragoso, Bruno; Moura, DelmindaPlastic pollution threatens life and human health, with microplastics (MP) linked to seafood consumption. MPs enter aquaculture through the environment and from aquaculture gear. During aquaculture production, plastic is used in nets and sacks for the growth process and in collecting and processing so it becomes important to expand the knowledge about how much MPs are present in seafood. The aim was to investigate the presence of MPs in three bivalve’s species; oysters (Crassostrea gigas), clams (Ruditapes decussatus), and mussels (Mytilus galloprovincialis) produced in offshore and intertidal aquaculture in two different climate conditions. Water, bivalves and sediments were collected from each site and abundance size, colour, type and composition of the MPs polymers analysed. The most common colour in offshore aquaculture was blue while in intertidal was black, and the type was fragments. Sixty per cent of bivalves did not have MPs in their tissues Bivalves from offshore aquaculture was less impacted by MPs probably due to the hydrographic conditions and distance from the coast. Most of MPs ingested by bivalves were related to the plastic type used in aquaculture materials. Transformative solutions and/or procedures to eliminate plastic from aquaculture equipment are needed, and depuration might be a practical solution.
- Aquaculture in the crossroad of microplastic contaminationPublication . Bebianno, Maria; Manthopoulos, Michael; Nathan, Justine; Cristina, Sónia; Ribeiro, Laura; Luna-Araújo, Ravi; Icely, John; Dias Duarte Fragoso, Bruno; Moura, DelmindaPlastic pollution threatens life and human health, with microplastics (MP) linked to seafood consumption. MPs enter aquaculture through the environment and from aquaculture gear. During aquaculture production, plastic is used in nets and sacks for the growth process and in collecting and processing so it becomes important to expand the knowledge about how much MPs are present in seafood. The aim was to investigate the presence of MPs in three bivalve's species; oysters (Crassostrea gigas), clams (Ruditapes decussatus), and mussels (Mytilus galloprovincialis) produced in offshore and intertidal aquaculture in two different climate conditions. Water, bivalves and sediments were collected from each site and abundance, size, colour, type and composition of the MPs polymers analysed. The most common colour in offshore aquaculture was blue while in intertidal was black, and the type was fragments. Sixty per cent of bivalves did not have MPs in their tissues. Bivalves from offshore aquaculture was less impacted by MPs probably due to the hydrographic conditions and distance from the coast. Most of MPs ingested by bivalves were related to the plastic type used in aquaculture materials. Transformative solutions and/ or procedures to eliminate plastic from aquaculture equipment are needed, and depuration might be a practical solution.
- A avaliação de risco sísmico no Algarve: efeito de sítioPublication . Albardeiro, L.; Moura, DelmindaAs características físicas locais traduzem no seu todo, aquilo a que se designa por efeito de sítio, ou seja, a resposta do substrato geológico a um determinado estímulo como é, neste caso, a propagação de uma onda sísmica. Face a este estímulo, a conjugação dos vários atributos físicos locais, pode resultar na amplificação do movimento do substrato, no aumento do tempo do movimento e na geração de movimentos diferenciais. Este tipo de efeito designa-se por agravamento.