Fault systems of Upper Triassic outcrops in Coimbra region

Poster apresentado ao VIII Congresso Nacional de Geologia, em Braga (9-16 de Julho 2010)A partir da análise estrutural dos sistemas de falhas em afloramentos do Triásico Superior localizados na região de Coimbra, na Bacia Lusitânica, foi possível definir famílias e sub-famílias de falhas. Este trabalho permitiu reconhecer que os acidentes tectónicos extensionais que afectaram os depósitos do Triásico nesta região, durante toda a evolução do contexto tectónico do Mesozóico foram sistematicamente reactivados nos regimes compressivos do final do Mesozóico e Cenozóico.From the structural analysis of the fault system in the Upper Triassic outcrops, located in the Coimbra region of the Lusitanian Basin, it was possible to define fault families and subfamilies. This recognizing that the extensional tectonic strutures that affected the Triassic deposits from this region, were systematically reactivated during the Late Mesozoic and Cenozoic compressive regimes

Influence of speciation in the bioavailability of cadmium to an isopod

Doutoramento em BiologiaDevido às actividades antropogénicas várias substâncias químicas têm sido introduzidas no meio ambiente em concentrações que de outro modo não ocorreriam de forma tão elevada naturalmente. Assim, o conhecimento acerca das características de um químico, tais como, o potencial para se acumular em diferentes níveis tróficos, a sua mobilidade dentro do ecossistema, a toxicidade específica e a bioacumulação, é fundamental para compreender os seus efeitos nos ecossistemas. Esta tese investiga a influência de especiação, na biodisponibilidade do cádmio (Cd) para o isópode Porcellio dilatatus, incluindo os efeitos de especiação do metal: (i) na assimilação do Cd, (ii) no modo como o Cd se distribui internamente no organismo, e (iii) como a sobrevivência e a reprodução são afectadas em isópodes terrestres. Num primeiro ensaio laboratorial avaliou-se a importância da transferência trófica na assimilação do Cd em P. dilatatus. Para tal analisou-se a eficiência de assimilação (EA) do Cd em isópodes, adicionado superficialmente ao alimento (alface) na forma de Cd(NO3)2 e contaminando o meio de crescimento da alface. A hipótese era de que a alface contaminada biologicamente através do cultivo em meio hidropónico contaminado teria uma maior proporção de complexos com proteína ou conjugado na forma de Cd (ex. Cd cisteína). A EA de Cd foi maior entre os isópodes que foram alimentados com o sal (71%, SE = 7%), do que entre os isópodes que se alimentaram de alface contaminada biologicamente (52%, SE = 5%), demonstrando-se assim num teste laboratorial que é provável que a especiação do Cd influencie a taxa de assimilação e acumulação do Cd. Na experiência alimentar que se seguiu, estudou-se em detalhe a especiação do metal comparando as EA do Cd conjugado com cisteína (Cd(Cys)2) e na forma de Cd(NO3)2, com os quais se contaminou gelatina com alface. A utilização de Cd-cisteína, proporcionou uma forma experimental para explorar a biodisponibilidade do Cd complexado dentro do tecido biológico. Como esperado, a EA de Cd em isópodes alimentados com nitrato de Cd (64%, SE = 5%) foi maior do que no caso de isópodes alimentados com o conjugado de cisteína (20%, SE = 3%). De seguida estudou-se a distribuição subcelular das espécies de Cd assimilado através de um processo de fraccionamento. Supunha-se que as diferenças de especiação de Cd reflectiria diferentes estratégias de compartimentalização, com consequências ao nível da detoxificação, armazenamento celular e distribuição subcelular do metal. O “sequestro” na forma de metal biologicamente detoxificado (BDM = proteínas estáveis ao calor - HSP e grânulos ricos em metal - RMG) foi maior nos isópodes alimentados com Cd(NO3)2, sugerindo que são mais eficientes na detoxificação de Cd (22%) do que quando alimentados com Cd(Cys)2 (15%). Foi também demonstrado que os isópodes alimentados com Cd(Cys)2 possuíam níveis de armazenamento de Cd superior nas fracções sensíveis ao metal (MSF = organelos e proteínas desnaturadas pelo calor - HDP) consideradas fracções potencialmente vulneráveis e afectando os isópodes em termos de toxicidade. As diferentes distribuições internas que se seguiram à assimilação e detoxificação das diferentes espécies de Cd foram finalmente avaliadas em termos da sobrevivência e reprodução dos isópodes. O tratamento com Cd(Cys)2 teve maior mortalidade, provavelmente devido à maior disponibilidade de Cd ingerido com implicações ao nível dos processos fisiológicos. Os isópodes alimentados com Cd(NO3)2 armazenaram o Cd nos MRG, como estratégia de detoxificação, sendo mais eficientes a detoxificar o Cd ainda que aumentando a concentração total do metal que se tornou menos tóxico para o isópode. Desta forma, o Cd nos grânulos não estava disponível para os processos fisiológicos e deixou de ser tóxico. Isso poderia estar relacionado com a resistência e tolerância aos metais devido à capacidade dos isópodes compartimentalizarem o Cd no hepatopâncreas, que actua como um mecanismo de detoxificação e contribui para a tolerância a altos níveis de cádmio. Em termos de parâmetros reprodutivos, observou-se uma redução de gestações e duração da gestação na presença de ambas as espécies de metal, mas no caso do Cd(Cys)2 as gravidezes não se concluíram. O número de jovens produzido por fêmeas alimentadas com Cd(NO3)2 foi menor do que no controlo, mas os pesos dos juvenis foram superiores. Finalmente sugere-se assim que esta abordagem seja considerada em estudos do movimento trófico de metais nas cadeias alimentares dado que se espera que a especiação de metais implique diferentes fluxos, dentro de uma dada cadeia trófica.Human activities have introduced several chemicals into the environment that otherwise would not be found in such high concentrations in nature. Therefore the knowledge about the characteristics of a chemical, such as the potential to accumulate at different trophic levels, mobility within the ecosystem and specific toxicity and bioaccumulation in organisms needs to be achieved in order to understand its effects on the ecosystems. The present thesis investigates the influence of speciation, in the bioavailability of cadmium (Cd) to the isopod Porcellio dilatatus, including the effects of metal speciation in: (i) Cd assimilation, (ii) the way Cd distributes internally within the organism, and (iii) how survival and reproduction is affected in terrestrial isopods. In a first laboratory trial the importance of trophic transfer to Cd assimilation in P. dilatatus was evaluated. This was carried out by examining the assimilation efficiency (AE) of Cd in isopods provided with food (lettuce) superficially amended with Cd(NO3)2 and provided with lettuce grown in Cd-contaminated media. The hypothesis was that lettuce biologically contaminated via hydroponic culture in contaminated media would have a high proportion of Cd in the form of Cd-protein complexes or Cd-S-conjugates (e.g. Cdcysteine). AE of Cd was greater among isopods that were fed the simple salt (71%, SE=7%), than among isopods feeding on biologically contaminated lettuce (52%, SE=5%), hence demonstrating that speciation of Cd is likely to influence the rate of Cd assimilation and accumulation in a laboratory test. In a following dietary experiment, metal speciation was further studied by comparing AE using Cd as Cd cysteinate (Cd(Cys)2) and Cd(NO3)2 deployed in contaminated gelatines containing lettuce. The use of Cd-cysteinate provided an experimental device to explore the bioavailability of Cd that is complexed within biological tissue. As hypothesized the AE of Cd by isopods fed with Cd nitrate (64%, S.E.=5%) was higher than in the case of isopods fed with Cd-cysteine conjugate (20%, S.E.=3%). The subcellular distribution of the assimilated Cd species was then studied with a fractionating procedure. It was assumed that differences in Cd speciation would reflect different compartmentalization strategies with consequences at the manner by which metal was detoxified, stored in cells and distributed at subcellular level. Sequestration as biologically detoxified metal (BDM = heat stable proteins - HSP and metal-rich granules - MRG) was higher in isopods fed with Cd(NO3)2 suggesting that they are more efficient at detoxifying Cd (22%) than when fed with Cd(Cys)2 (15%). It was also shown that isopods fed with Cd(Cys)2 had a higher storage level of Cd in the metal-sensitive fractions (MSF = organelles and heat denatured proteins - HDP) being considered potentially vulnerable fractions affecting isopods in terms of toxicity. The different internal distributions that followed the assimilation and detoxification of different Cd species were finally evaluated as survival and reproduction in isopods. The Cd(Cys)2 treatment had the highest mortality probably due to higher availability of the ingested Cd that impaired physiological processes. Isopods fed with Cd(NO3)2 stored Cd in the MRG as a detoxification strategy hence they were more efficient at detoxifying Cd which may had lead to increased metal body burdens although being less toxic to the isopod. In this way, Cd in granules was not available for the physiological processes and became non toxic. This could also be related to metal tolerance and resistance that may be attributed to the ability of isopods to compartmentalize Cd in the hepatopancreas, which acts as a detoxification mechanism and contributes to tolerance to high cadmium levels. In the presence of both metal species a reduction of pregnancies and pregnancy duration was observed in terms of reproductive endpoints but in the case of Cd(Cys)2 all pregnancies were inconclusive. The number of juveniles delivered per female fed with Cd(NO3)2 contaminated food was lower than in the control but the juvenile weights were higher. In sum, it can be suggested that future studies examining the trophic movement of metals in food chains should consider this kind of approach where different flows within a trophic chain are expected depending on metal speciation

Study of alluvial fan facies from the Upper Triassic in a Coimbra region outcrop

Poster apresentado ao VIII Congresso Nacional de Geologia, em Braga (9-16 de Julho 2010)A realização de um perfil litostratigráfico de pormenor em depósitos triásicos na região de Coimbra permitiu o reconhecimento de fácies sedimentares, a sua caracterização e interpretação tectonosedimentar. As conclusões encontram-se em concordância com as etapas iniciais da evolução geológica da Bacia Lusitânica largamente exposta na bibliografia existente.construction of a detailed litostratigraphyc profile from the Upper Triassic in a Coimbra region outcrop, allowed the recognition of sedimentary facies, characterization and tectono-sedimentary interpretation. The conclusions are in concordance with previous knowledge, of the initial stages of the geological evolution in the Lusitanian Basin

Effects on survival and reproduction of Porcellio dilatatus exposed to different Cd species

The woodlouse Porcellio dilatatus (Crustacea) is a suitable model organism as a biological indicator for the toxic effects evaluation induced by pollutants exposure in the environment. In this study, the influence of cadmium (Cd) species on survival and reproduction of isopods was investigated. Survival, growth and reproductive parameters (time to pregnancy, pregnancy duration, pregnancy and abortion occurrence, number of juveniles per female and juvenile weight) were recorded after isopods were exposed to two species of Cd deployed in food: Cd(Cys)(2) and Cd(NO(3))(2). There was a difference between survival rates of exposed males and females to both Cd species but in the case of Cd(NO(3))(2) these differences were more accentuated, with females having higher survival rates. In the presence of both metal species a reduction in the number of pregnancies and pregnancy duration was observed, while in the case of Cd(Cys)(2) all pregnancies were inconclusive. The number of juveniles delivered per female fed with Cd(NO(3))(2) contaminated food was lower than in the control, whereas the juvenile weights were higher. To the best of our knowledge, the present study is the first toxicity test demonstrating that metal speciation affects reproduction in isopods. Cd(Cys)(2) showed to be the most toxic of the contaminants tested in this long term exposure and capable of jeopardizing the reproduction efforts of isopods.publishe

Cadmium assimilation in the terrestrial isopod, Porcellio dilatatus - Is trophic transfer important?

Terrestrial isopods have become important tools for the ecotoxicological assessment of metal-contaminated soils. Their value as an invertebrate model is partly because of their extraordinary capacity to bioaccumulate toxic metals from the environment. Replication of this accumulation process in the laboratory has in the past relied on the amendment of organic food substrates through the addition of inorganic metal salts. However, the bioavailability of the metals when presented through doping regimes may differ from the bioavailability of metals in nature, because over time metals become biologically compartmentalised and form complexes with organic molecules. This study examines the differential bioavailability of Cd to the terrestrial isopod, Porcellio dilatatus, when presented as either a Cd-amended diet or pre-incorporated biologically into lettuce (Lactuca sativa). Isopods were either provided with lettuce contaminated superficially with Cd(NO3)(2) or lettuce grown hydroponically in growth media containing 100 mu M Cd(NO3)(2). Assimilation efficiency of Cd was greater among isopods that were fed the amended diet (71%, S.E.=7%), than among isopods feeding on biologically contaminated lettuce (52%, S.E.=5%) and demonstrates that speciation of Cd is likely to influence the rate of Cd assimilation and accumulation in a laboratory test. (c) 2006 Elsevier B.V. All rights reserved.FCT/POCTI/BSE/48757/2002FCT/SFRH/BPD/ 8348/2002FCT/SFRH/ BD 18942/ 200

The influence of metal speciation on the bioavailability and sub-cellular distribution of cadmium to the terrestrial isopod, Porcellio dilatatus

Cadmium is a non-essential toxic metal that is able to bioaccumulate in both flora fauna and has the potential to biomagnify in some food chains. However, the form in which cadmium is presented to consumers can alter the bioavailability and possibly the internal distribution of assimilated Cd. Previous studies in our laboratory highlighted differences in Cd assimilation among isopods when they were provided with a plant-based food with either Cd biologically incorporated into plant tissue or superficially amended with ionic Cd(2+). Cd is known for its high affinity for sulphur ligands in cysteine residues which form the basis for metal-binding proteins such as metallothionein. This study compares Cd assimilation efficiency (AE) in Porcellio dilatatus fed with food amended with either cadmium cysteinate or cadmium nitrate in an examination of the influence of Cd speciation on metal bioavailability followed by an examination of the sub-cellular distribution using a centrifugal fractionation protocol. As hypothesized the AE of Cd among isopods fed with Cd(NO(3))(2) (64%, SE = 5%) was higher than AE for isopods fed with Cd(Cys)(2) (20%, SE = 3%). The sub-cellular distribution also depended on the Cd species provided. Those isopods fed Cd(Cys)(2) allocated significantly more Cd to the cell debris and organelles fractions at the expense of allocation to metal-rich granules (MRG). The significance of the difference in sub-cellular distribution with regard to toxicity is discussed. This paper demonstrates that the assimilation and internal detoxification of Cd is dependent on the chemical form of Cd presented to the isopod. (C) 2010 Elsevier Ltd. All rights reserved

The influence of metal speciation on the bioavailability and sub-cellular distribution of cadmium to the terrestrial isopod, Porcellio dilatatus

Cadmium is a non-essential toxic metal that is able to bioaccumulate in both flora fauna and has the potential to biomagnify in some food chains. However, the form in which cadmium is presented to consumers can alter the bioavailability and possibly the internal distribution of assimilated Cd. Previous studies in our laboratory highlighted differences in Cd assimilation among isopods when they were provided with a plant-based food with either Cd biologically incorporated into plant tissue or superficially amended with ionic Cd(2+). Cd is known for its high affinity for sulphur ligands in cysteine residues which form the basis for metal-binding proteins such as metallothionein. This study compares Cd assimilation efficiency (AE) in Porcellio dilatatus fed with food amended with either cadmium cysteinate or cadmium nitrate in an examination of the influence of Cd speciation on metal bioavailability followed by an examination of the sub-cellular distribution using a centrifugal fractionation protocol. As hypothesized the AE of Cd among isopods fed with Cd(NO(3))(2) (64%, SE = 5%) was higher than AE for isopods fed with Cd(Cys)(2) (20%, SE = 3%). The sub-cellular distribution also depended on the Cd species provided. Those isopods fed Cd(Cys)(2) allocated significantly more Cd to the cell debris and organelles fractions at the expense of allocation to metal-rich granules (MRG). The significance of the difference in sub-cellular distribution with regard to toxicity is discussed. This paper demonstrates that the assimilation and internal detoxification of Cd is dependent on the chemical form of Cd presented to the isopod. (C) 2010 Elsevier Ltd. All rights reserved

Water-extractable priority contaminants in LUFA 2.2 soil: back to basics, contextualisation and implications for use as natural standard soil

The natural LUFA 2.2 standard soil has been extensively used in hazard assessment of soil contaminants, combining representation with ecological relevance for accurate risk evaluation. This study revisited the water-extractable fraction of LUFA 2.2 soil, through consecutive soil wet-dry cycles and discusses implications of use as standard substrate in derivation of ecotoxicological data and toxicity thresholds. Potentially bioavailable contents of metals (177.9-888.7 µg/l) and the 16 polycyclic aromatic hydrocarbons (PAHs; 0.064-0.073 µg/l) were dependent on the number of soil wetting-drying cycles applied. Such contents were screened based on current EU guidelines for surface waters and reported toxicological benchmarks for aquatic organisms. Aqueous concentrations generally fit within recommended Environmental Quality Standards (EQS), except for Hg (0.13-0.22 µg/l; >Maximum Allowable Concentration-MAC-of 0.07 µg/l) and for the sum of benzo(g,h,i)perylene and indeno(1,2,3-cd)pyrene (0.005 µg/l; >double the Annual Average of 0.002 µg/l). Further, aqueous As, Zn, Cd, Ni and Cr concentrations exceeded 'lower benchmark' values for aquatic organisms, possibly reflecting an inadequate derivation for ecotoxicological data. In turn, PAHs in LUFA 2.2 soil aqueous extracts, whilst individually, are not likely to constitute a hazard to test biota exposed to its aqueous fractions. This study urges for potentially bioavailable fractions of reference and standard natural soils to be adequately characterized and addressed as part of the research aim, experimental approach and design, as well as the expected scope of the outcomes

Influence of seasons and land-use practices on soil microbial activity and metabolic diversity in the “Montado ecosystem”

The “Montado ecosystem” is important both economically and ecologically; this ecosystem is dominated by cork and holm oak trees (Quercus suber L. and Quercus rotundifolia Lam. respectively) combined with a rotation of crops/fallow/pastures. Diverse management strategies, deviating from the sustainable use of the ecosystem, have been implemented, from which arise some extreme situations of over-use or abandonment. To evaluate the effects of different soil use and management, namely extensive cropping, intensive pasture and abandonment, in the activity of soil microorganisms, dehydrogenase, acid phosphatase, b-glucosidase and urease activities, N-mineralization and nitrification rates were measured in different land-use practices, in different seasons (winter, spring and autumn). Also, the potential metabolic diversity was evaluated by analysis of community-level physiological profiles (CLPPs). Seasonal effects were evident with maximum activity occurring in rainy seasons (winter and autumn) and lower substrate utilization in winter. Significant correlations between most microbial parameters and soil water content reflect this seasonal effect. Although showing mainly a seasonal change, microbial parameters were able to distinguish the abandoned area, with a general low activity and differential exponential rates in the use of several substrates, such as amino acids, miscellaneous and polymers, probably associated with changes in organic matter quality.This study was funded by the EU FP5 VISTA project (EVK2-2002- 00168)