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2020 was an untypically difficult year. The global COVID-19 pandemic has forced the closure of various sectors of activity, including universities, laboratories and businesses, impelling researchers and technicians to temporarily halt their research or, at their best, to develop it in a limited way. Less recognised but equally significant was the direct impact of COVID-19 on the preservation and protection of cultural heritage. Online: 2021-2-10Publication: 2021-2-10, 2020 foi um ano atipicamente difícil. A pandemia global COVID-19 obrigou, a espaços, ao encerramento de vários sectores de atividade, incluindo universidades, laboratórios e empresas, levando a que, investigadores e técnicos, se vissem forçados a interromper temporariamente a sua investigação ou, na melhor das hipóteses, a desenvolvê-la de forma limitada. Menos reconhecido, mas igualmente significativo, foi o impacto direto da COVID-19 na preservação e proteção do património cultural. Online: 2021-2-10Publicação: 2021-2-10

A year has passed since the new editorial and direction board assumed the direction of the journal [1]. We would like to highlight some changes that have been implemented, particularly those involving the image and management of Conservar Património, remarking that some changes are still under development. Online: 2020-11-27Publication: 2020-11-27, Passado um ano desde a entrada em funções da nova direcção da revista [1], vimos assinalar algumas mudanças que foram implementadas, nomeadamente aquelas que implicam a imagem e o funcionamento da Conservar Património, fazendo notar que algumas se encontram em desenvolvimento. Online: 2020-11-27Publicação: 2020-11-27

Microbiology (2009), 155, 3476–3490 The presence and deteriorating action of micro-organisms on monuments and stone works of art have received considerable attention in the last few years. Knowledge of the microbial populations living on stone materials is the starting point for successful conservation treatment and control. This paper reviews the literature on cyanobacteria and chlorophyta that cause deterioration of stone cultural heritage (outdoor monuments and stone works of art) in European countries of the Mediterranean Basin. Some 45 case studies from 32 scientific papers published between 1976 and 2009 were analysed. Six lithotypes were considered: marble, limestone, travertine, dolomite,sandstone and granite. A wide range of stone monuments in the Mediterranean Basin support considerable colonization of cyanobacteria and chlorophyta, showing notable biodiversity. About 172 taxa have been described by different authors, including 37 genera of cyanobacteria and 48 genera of chlorophyta. The most widespread and commonly reported taxa on the stone cultural heritage in the Mediterranean Basin are, among cyanobacteria, Gloeocapsa, Phormidium and Chroococcus and, among chlorophyta, Chlorella, Stichococcus and Chlorococcum. The results suggest that cyanobacteria and chlorophyta colonize a wide variety of substrata and that this is related primarily to the physical characteristics of the stone surface, microclimate and environmental conditions and secondarily to the lithotype.

Annals of Microbiology, 59 (4) 705-713 (2009) The influence of open porosity, water absorption capillarity, water vapour permeability, surface roughness, stone pH and chemical composition on stone bioreceptivity to phototrophic microorganisms was assessed by means of a thorough stone characterisation with subsequent artificially inoculation of limestone samples with a multi-species phototrophic culture and placing them inside a growth chamber for 90 days. A principal component analysis and an analysis of variance(ANOVA) were carried out in order to evaluate the direct relationships between stone bioreceptivity and petrophysical properties. From the principal component analysis, two main components were obtained and assigned a petrophysical/photosynthetic biomass meaning. Stone bioreceptivity, quantified by the amount of chlorophyll a and intensity of chlorophyll a fluorescence present on the stone samples after 90 days-incubation, was included in both principal components. The first component was linked to the amount of chlorophyll a and was highly and linearly associated to capillarity and roughness,and less associated with open porosity and water vapour permeability. The second component, linked to the intensity of chlorophyll a fluorescence measured on the stone surfaces, was not linearly associated with the petrophysycal properties,showing the fallibility of this in vivo chlorophyll quantification technique on the estimation of photosynthetic biomass growing on stone materials, particularly when endolithic growth occurs.

Science of the total environment 405(2008) 278-285 In order to understand the biodeterioration process occurring on stone monuments, we analyzed the microbial communities involved in these processes and studied their ability to colonize stones under controlled laboratory experiments. In this study, a natural green biofilm from a limestone monument was cultivated, inoculated on stone probes of the same lithotype and incubated in a laboratory chamber. This incubation system, which exposes stone samples to intermittently sprinkling water, allowed the development of photosynthetic biofilms similar to those occurring on stone monuments. Denaturing gradient gel electrophoresis (DGGE) analysis was used to evaluate the major microbial components of the laboratory biofilms. Cyanobacteria, green microalgae, bacteria and fungi were identified by DNA-based molecular analysis targeting the 16S and 18S ribosomal RNA genes. The natural green biofilm was mainly composed by the Chlorophyta Chlorella, Stichococcus, and Trebouxia, and by Cyanobacteria belonging to the genera Leptolyngbya and Pleurocapsa. A number of bacteria belonging to Alphaproteobacteria, Bacteroidetes and Verrucomicrobia were identified, as well as fungi from the Ascomycota. The laboratory colonization experiment on stone probes showed a colonization pattern similar to that occurring on stone monuments. The methodology described in this paper allowed to reproduce a colonization equivalent to the natural biodeteriorating process.

Commonwealth war cemeteries commemorate the fallen of both world wars. Every casualty is remembered with a memorial or on a headstone. However, the headstones need to be maintained extensively, as microorganisms easily colonise them, affecting legibility and the stone substrate in the longer term. In the past, pesticides and other chemicals were popular to clean headstones, but due to raised environmental concerns, new treatment strategies are necessary. Within conservation science, enzymes have emerged as a popular tool for restoration. However, studies related to the use of enzymes for stone conservation are limited. Within this preliminary study, we applied commercially available enzyme-based treatments on biofouled natural building stones in the laboratory and in situ. Photography and spectrophotometry were used to monitor the effect of the treatment. The application of enzymes resulted in rapid disintegration of biological pigments, whereas visual improvement occurred more gradually. The successful application of enzymes suggests their potential to replace pesticides as the principal cleaning agent for headstones and natural building stones in a more general fashion.

Unlike the spectacular speleothems that can often be found in numerous caves, vermiculations are rather unassuming formations, whose origin and evolution still subject of several heated debates. In order to provide a quantitative basis for the understanding of the nature and evolution of vermiculations in karst environments, the geochemical properties of one of the most important karst systems of southern Italy, the Pertosa-Auletta Cave, were studied through a comprehensive approach which included elemental, mineralogical and microscopy analyses. The chemical element abundances, mineral composition and microstructure of the vermiculations covering the entire range of morphologies and colours observed in the case-study cave were investigated, thus providing the first quantitative record of these traits. The vermiculations presented exceptional diversity in their morphology, colour, chemical and mineral composition, with it being due to exogenous determinants such as the deposition of stream sediments or organic matter as well as the development of photoautotrophic communities. They were invariably composed of calcite, associated to quartz as well as clays and other secondary minerals, the formation of which may be biologically mediated. This occurrence, and the evidences of microbial activity observed through dissolution traces, support the possible involvement of biogenic processes in vermiculation development.