Characterization and rehabilitation of the “Porta Férrea” stone materials,University of Coimbra,Portugal     

Lídia Catarino  Francisco P. S. C. Gil  Mário Quinta-Ferreira  Fernando Marques 《Environmental Earth Sciences》2018,77(11):416

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Biochemical alterations in juvenile carp (Cyprinus carpio) exposed to zinc: glutathione reductase as a target     

Franco JL  Posser T  Mattos JJ  Sánchez-Chardi A  Trevisan R  Oliveira CS  Carvalho PS  Leal RB  Marques MR  Bainy AC  Dafre AL 《Marine environmental research》2008,66(1):88-89

The aim of this study was to investigate biochemical changes in juvenile carp (Cyprinus carpio) exposed to zinc chloride (10, 30 and 100 microM) for a period of 48 h. Zinc exposure caused a concentration-dependent reduction in glutathione reductase (GR) activity in gills, liver and brain. Gill glutathione S-transferase (GST) was reduced when animals were exposed to the highest concentration of 100 microM zinc. The phosphorylation of p38(MAPK) increased in the brain of fish exposed to zinc 100 microM, while phosphorylation of the extracellular signal-regulated protein kinase 1/2 (ERK1/2) and c-Jun N-terminal protein kinase 1/2 (JNK1/2) remained unchanged. Expression of proteins HSP60 and HSP70 were not affected by zinc exposure. Considering the significant concentration-dependent inhibition of GR in all tissues analyzed, this enzyme could be a potential biomarker of exposure to zinc, which has to be confirmed.  相似文献   

The trade of live crustaceans in Portugal: space for technological improvements     

Barrento  Sara; Marques  Antonio; Pedro  Sonia; Vaz-Pires  Paulo; Nunes  Maria Leonor 《ICES Journal of Marine Science》2008,65(4):551-559

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A near-bottom geophysical traverse of the Reykjanes Ridge     

John S.F. Shih  Tanya Atwater  Marcia McNutt 《Earth and Planetary Science Letters》1978,39(1):75-83

We report here the results of a near-bottom geophysical survey of the Reykjanes Ridge, a mid-ocean ridge that is oriented obliquely to the perpendicular spreading direction. From a combination of the bathymetric profiles, side-scan sonar data, and regional bathymetric maps we infer that the present center of spreading is made up of a number of N15°E-trending en echelon ridge segments in the southern half of our survey area. Insufficient data prevent the identification of the spreading pattern in the northern half. The side-scan records show that the ridge flanks are highly fractured by inward-facing faults displaced 40 m or less and trending in a N21°E direction. The lack of side-scan features parallel to the spreading direction except in the southernmost portion of the survey area suggests that the ridge segments are not connected by transform faults in the usual sense. Although the mechanism by which en echelon ridge segments can be maintained during sea-floor spreading over time is unclear, similar patterns of crustal accretion have been reported on Iceland. It appears that the accretionary processes along the Reykjanes Ridge are more related to those of Iceland than to those of typical mid-ocean ridges.  相似文献   

Nature and role of CO2 in some hot and cold HCO3/Na/CO2-rich Portuguese mineral waters: a review and reinterpretation     

José M. Marques  Paula M. M. Carreira  Luís Aires-Barros  Rui C. Graça 《Environmental Geology》2000,40(1-2):53-63

 At the northern part of the Portuguese mainland, the upflow zone of several hot and cold HCO₃/Na/CO₂-rich mineral waters is mainly associated with important NNE–SSW faults. Several geochemical studies have been carried out on thermal and non-thermal hydromineral manifestations that occur along or near these long tectonic alignments. The slight chemical differences that exist between these meteoric hot and cold HCO₃/Na/CO₂-rich mineral waters seem to be mainly caused by CO₂. δ¹³C_(TIDC) values observed in these groundwaters range between –6.00 and –1.00‰ versus V-PDB (V denotes Vienna, the site of the International Atomic Energy Agency; PDB originates from the CaCO₃ of the rostrum of a Cretaceous belemnite, Belemnitella americana, collected in the Peedee formation of South Carolina, USA) indicating a deep-seated (mantle) origin for most of the CO₂. Nevertheless, in the case of the heavier δ¹³C_(TIDC) values, the contribution of metamorphic CO₂ or the dissolution of carbonate rock levels at depth cannot be excluded. Concerning the hot waters, the lack of a positive ¹⁸O-shift should be attributed to water-rock interaction in a low temperature environment, rather than to the isotopic influence of CO₂ on the δ¹⁸O-value of the waters. Received: 9 August 1999 · Accepted: 8 March 2000  相似文献   

Local disappearance of bivalves in the Azores during the last glaciation     

Sérgio P. Ávila  Patrícia Madeira  C. Marques da Silva  Mário Cachão  Bernard Landau  Rui Quartau  A. M. de Frias Martins 《第四纪科学杂志》2008,23(8):777-785

The Pleistocene (Eemian) outcrops of Lagoinhas and Prainha, located at Santa Maria Island (Azores), were investigated and their fossil mollusc content reported. These studies revealed that the last glaciation affected two groups of molluscs: the ‘warm‐guest’ gastropods with West African or Caribbean affinities (e.g. Conus spp., Cantharus variegatus, Bulla amygdala, Trachypollia nodulosa) and shallow bivalve species mainly associated with sandy habitats (Ensis minor, Lucinella divaricata, and probably Laevicardium crassum). In this paper we focus on this group of bivalves, which has since locally disappeared from the Azores. We relate the local disappearance of these bivalves in the Azores with the lack of sand in the shelf. The specific characteristics of the Santa Maria shelf combined with the sea‐level drop during the Weichselian prevented deposition of the lowstand deposits and permitted erosion of the previous ones, leaving the shelf without a sediment cover. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

The Response of Estuarine Macrobenthic Communities to Natural- and Human-Induced Changes: Dynamics and Ecological Quality     

João Magalhães Neto  Heliana Teixeira  Joana Patrício  Alexandra Baeta  Helena Veríssimo  Rute Pinto  João Carlos Marques 《Estuaries and Coasts》2010,33(6):1327-1339

Anthropogenic activities are a disturbance factor of coastal systems and can be widely recognized as a major threat to the health of coastal systems. However, natural events cannot be disregarded from management issues because of their significant influence on the communities living in these areas. Based on long-term subtidal data from the Mondego Estuary (Portugal), the effects of natural events (e.g., floods and droughts) on macrobenthic communities were compared with the anthropogenic events. Sampling stations were grouped into characteristic zones (mouth, north arm, south arm) so the community dynamics of each of these estuarine areas could be followed over time. Environmental assessment was performed for stations using the Benthic Assessment Tool (BAT), and compared with the existing pressures. Human impacts persist over a number of years and gradually reduce ecosystem health, as discussed in the European Water Framework Directive. Paradoxically, natural events cause stronger impacts but are of a shorter duration, which allows for a faster recovery of macrobenthic communities. The study showed that caution should be taken when developing and implementing water policies so as not to disregard the importance of the different events (natural and human-caused) on the ecosystem health (e.g., community degradation and water quality and ecological quality status assessment).  相似文献   

Coastal vulnerability in barrier islands: The high risk areas of the Ria Formosa (Portugal) system     

Filipe Rafael Ceia  Joana Patrício  João Carlos Marques  João Alveirinho Dias 《Ocean & Coastal Management》2010,53(8):478-486

Coastal vulnerability in barrier island systems is extremely high. The barrier island shoreline is exposed to many threats, such as storm erosion, reductions in sediment longshore drift and sea level rise. Many of these threats to coastal areas, such as Ria Formosa, are likely to increase in the near future. The main objectives of the present study are to identify the areas in the system that are at most risk by assessing the evolution of the Ria Formosa barrier island system since the 1940s, and determine which interventions would be necessary to protect these areas.The coastal vulnerability of the system was assessed based on current literature, data available from official institutions, and aerial and terrestrial in situ examination. The results obtained for the evolution of the Ria Formosa coastal system reveal that there are several vulnerable areas that have very dynamic processes, such as extremely high evolution rates of islands and inlets. Human actions that affect the whole system, namely the construction of many physical structures, are the main cause of the instability. Moreover, as several stakeholders are involved, efficient management of the coastal system is imperative. Extensive and careful interventions are urgently needed to avoid irreversible negative impacts on the barrier island system. Three types of techniques could be adopted to deal with the threats to barrier islands: hard stabilization, soft techniques, and non-structural alternatives. However, using hard techniques has many negative effects compared to soft techniques, and as a result it is necessary to remove existing structures from the areas at most risk.  相似文献   

Mechanical Behavior of Microbially Induced Calcite Precipitation Cemented Sand     

de Rezende  Igor Marasini  Prietto  Pedro Domingos Marques  Thomé  Antônio  Dalla Rosa  Francisco 《Geotechnical and Geological Engineering》2022,40(4):1997-2008

Geotechnical and Geological Engineering - New sustainable ground improvement techniques have been recently required for applications in onshore and offshore geotechnical structures. The...  相似文献   

Sedimentology,three‐dimensional geobody reconstruction and carbon dioxide origin of Pleistocene travertine deposits in the Ballık area (south‐west Turkey)          下载免费PDF全文

Hannes Claes  Jeroen Soete  Koen Van Noten  Hamdy El Desouky  Marcelle Marques Erthal  Frank Vanhaecke  Mehmet Özkul  Rudy Swennen 《Sedimentology》2015,62(5):1408-1445

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