Multi-proxy assessment of coral reef formation and biotic-abiotic diversity in an urban coastal reef ecosystem in northeastern Brazil.

Coral reefs are habitats with high animal and mineral diversity and are subject to both climate change and anthropogenic impacts. This article presents novel and relevant data on the Seixas coral reef environment's geological, sedimentological, mineralogical, and biotic aspects in Paraíba State, northeastern Brazil. The aim of this study is to evaluate the processes of reef formation and the diversity of coral reef species in urban coastal environments in northeastern Brazil using a multi-proxy approach. Materials and methods employed to analyze the formation and diversity of biotic and abiotic species include (a) bathymetric survey, (b) collection of sedimentological, mineralogical, and granulometric data, (c) geological and stratigraphic determination, and (d) identification of biotic and abiotic species. Mineralogical slide results reveal that the Seixas Reef is a recent biogenic coral-algal carbonate formation associated with coastline evolution, high coastal sedimentation, and changes that occurred alongside sea-level rise (Holocene-Quaternary period). The diversity results indicate that benthic organism settlement occurred on a consolidated arenite base, with the fauna undergoing continuous succession processes. It can be concluded that this coral reef is highly vulnerable due to the material of its formation and comprises subsectors with high diversity (fore reef) and others with low diversity (reef top), which are affected by both anthropogenic and natural factors. Studies of this nature can contribute to understanding the evolution of coastal reefs, as their proximity to the continent makes them more vulnerable, and they experience direct physical impacts from fishing and tourist activities.

Study of mural paintings by Fulvio Pennacchi in São Paulo City by mineralogical techniques

The present research deals with two mural paintings made in 1947 with the fresco technique by Fulvio Pennacchi in the Catholic Chapel of the Hospital das Clínicas (São Paulo City, Brazil), namely the Virgin Annunciation and the Supper at Emmaus. This study regards the materials and painting techniques used by the artist, based on historical research,on in situ observations and laboratory analytical techniques (stereomicroscopy,scanning electron microscopy with an energy dispersive spectrometer, X-ray diffractometry, electron microprobe, images obtained with UV-light), aiming to improve the methods of characterization of objects of our cultural heritage, and to enhance its preservation accordingly. The results lead to the identification of the plaster components and of distinct layers in the frescoes, besides further information on grain size, impurities and textures, composition of pigments, and features of deterioration, such as efflorescences. The degree of degradation of the murals painting was assessed by this way. Our data suggest that a single layer of plaster was used by Pennacchi, as a common mortar with fine- and medium-grained aggregates. Differences in texture were obtained by adding gypsum to the plaster.

A presente pesquisa trata de duas pinturas murais feitas em 1947 por Fulvio Pennacchi com a técnica do afresco na Capela Católica do Hospital das Clínicas (São Paulo, Brasil), intituladas Anunciação da Virgem e Ceia de Emaús. Este estudo considera os materiais e as técnicas de pintura usadas pelo artista, baseado na pesquisa histórica, observações in situ e técnicas analíticas de laboratório (estereomicroscopia, microscopia eletrônica de varredura com detector de espectro de energia dispersiva, difração de raios X, microssonda eletrônica, imagens obtidas com luz ultravioleta), visando aperfeiçoar os métodos de caracterização de objetos do nosso patrimônio cultural, e otimizar sua preservação adequadamente. Os resultados conduziram à identificação dos componentes da argamassa e as diferentes camadas nos afrescos, além de informações sobre a granulação, impurezas e texturas, composição dos pigmentos, e feições de deterioração, tal como eflorescência. O grau de degradação das pinturas murais foi avaliado desta maneira. Nossos dados sugerem que Pennacchi usou uma camada única de argamassa com agregados de granulação fina a média. Diferenças na textura foram obtidas pela adição de gesso à argamassa.