Porto, Portugal
Porto, Portugal

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Miller A.Z.,University of Lisbon | Dionisio A.,University of Lisbon | Sequeira Braga M.A.,University of Minho | Hernandez-Marine M.,University of Barcelona | And 11 more authors.
Chemical Geology | Year: 2012

This paper reports the results of a study of biogenic Mn oxide minerals coating in a subsurface granite environment.This subterranean environment corresponds to galleries of a 16th century spring water tunnel dug throughout the granite bedrock located in Porto city (NW Portugal). Several techniques (XRD, FTIR, Raman, ICP-MS, TEM-EDS, FESEM-EDS, STEM-EDS and STXM-NEXAFS) were used to assess the mechanisms involved in the formation of manganese oxides, specifically birnessite and todorokite. These manganese oxides presented peculiar shapes, nano-dimensions, low degree of crystallinity, and high levels of some trace elements such as P, Ca, C, Al, Si, Ba and Zn. They were associated with large amounts of extracellular polymeric substances exuded by filamentous bacterial communities, which serve as nuclei for preferential precipitation of manganese oxides on the extracellular sheaths. Scientific assessment revealed that biological activity played a major role in the development of these manganese oxides. © 2012 Elsevier B.V.

Miller A.Z.,University of Lisbon | Hernandez-Marine M.,University of Barcelona | Jurado V.,Institute Recursos Naturales y Agrobiologia IRNAS | Dionisio A.,University of Lisbon | And 7 more authors.
Environmental Microbiology Reports | Year: 2012

In the last few years, geomicrobiologists have focused their researches on the nature and origin of enigmatic reticulated filaments reported in modern and fossil samples from limestone caves and basalt lava tubes. Researchers have posed questions on these filaments concerning their nature, origin, chemistry, morphology, mode of formation and growth. A tentative microbial origin has been elusive since these filaments are found as hollow tubular sheaths and could not be affiliated to any known microorganism. We describe the presence of similar structures in a 16th century granite tunnel in Porto, Northwest Portugal. The reticulated filaments we identify exhibit fine geometry surface ornamentation formed by cross-linked Mn-rich nanofibres, surrounded by a large amount of extracellular polymeric substances. Within these Mn-rich filaments we report for the first time the occurrence of microbial cells. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

Marques J.E.,University of Porto | Marques J.M.,University of Lisbon | Chamine H.I.,Polytechnic Institute of Porto | Chamine H.I.,University of Porto | And 12 more authors.
Geosciences Journal | Year: 2013

Mountains are often considered as the world's water towers. This paper presents a critical review on the research concerning the integrated assessment of groundwater resources of the mountain hydrogeologic system of Serra da Estrela Natural Park (central Portugal). The study area is the Zêzere river basin upstream of Manteigas village located at the Serra da Estrela Mountain in Central Portugal. It provides the source of strategic water resources for the Portuguese mainland, including normal groundwaters, thermomineral waters and surface waters. An integrated approach has been used to formulate a conceptual model for this complex mountain hydrogeological system by integrating the geological, morphotectonic, hydroclimatic, unsaturated soil zone, hydrogeological, hydrogeophysical, hydrogeochemical and isotopic data. This model has been useful to: i) evaluate the water resources; ii) provide the basis for a sustainable management of water resources, iii) design measures for groundwater exploitation and contamination control; and iv) set up land-use policies. © 2013 The Association of Korean Geoscience Societies and Springer-Verlag Berlin Heidelberg.

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