Dark-pigmented biodeteriogenic fungi in etruscan hypogeal tombs: New data on their culture-dependent diversity, favouring conditions, and resistance to biocidal treatments

Once upon a Time, There Was a Piece of Wood: Present Knowledge and Future Perspectives in Fungal Deterioration of Wooden Cultural Heritage in Terrestrial Ecosystems and Diagnostic Tools

Wooden Cultural Heritage (WCH) represents a significant portion of the world's historical and artistic heritage, consisting of immovable and movable artefacts. Despite the expertise developed since ancient times to enhance its durability, wooden artefacts are inevitably prone to degradation. Fungi play a pivotal role in the deterioration of WCH in terrestrial ecosystems, accelerating its decay and leading to alterations in color and strength. Reviewing the literature of the last 25 years, we aimed to provide a comprehensive overview of fungal diversity affecting WCH, the biochemical processes involved in wood decay, and the diagnostic tools available for fungal identification and damage evaluation. Climatic conditions influence the occurrence of fungal species in threatened WCH, characterized by a prevalence of wood-rot fungi (e.g., Serpula lacrymans, Coniophora puteana) in architectural heritage in temperate and continental climates and Ascomycota in indoor and harsh environments. More efforts are needed to address the knowledge fragmentation concerning biodiversity, the biology of the fungi involved, and succession in the degradative process, which is frequently centered solely on the main actors. Multidisciplinary collaboration among engineers, restorers, and life sciences scientists is vital for tackling the challenges posed by climate change with increased awareness. Traditional microbiology and culture collections are fundamental in laying solid foundations for a more comprehensive interpretation of big data.

Fungal biodeterioration and preservation of cultural heritage, artwork, and historical artifacts: extremophily and adaptation

SUMMARYFungi are ubiquitous and important biosphere inhabitants, and their abilities to decompose, degrade, and otherwise transform a massive range of organic and inorganic substances, including plant organic matter, rocks, and minerals, underpin their major significance as biodeteriogens in the built environment and of cultural heritage. Fungi are often the most obvious agents of cultural heritage biodeterioration with effects ranging from discoloration, staining, and biofouling to destruction of building components, historical artifacts, and artwork. Sporulation, morphological adaptations, and the explorative penetrative lifestyle of filamentous fungi enable efficient dispersal and colonization of solid substrates, while many species are able to withstand environmental stress factors such as desiccation, ultra-violet radiation, salinity, and potentially toxic organic and inorganic substances. Many can grow under nutrient-limited conditions, and many produce resistant cell forms that can survive through long periods of adverse conditions. The fungal lifestyle and chemoorganotrophic metabolism therefore enable adaptation and success in the frequently encountered extremophilic conditions that are associated with indoor and outdoor cultural heritage. Apart from free-living fungi, lichens are a fungal growth form and ubiquitous pioneer colonizers and biodeteriogens of outdoor materials, especially stone- and mineral-based building components. This article surveys the roles and significance of fungi in the biodeterioration of cultural heritage, with reference to the mechanisms involved and in relation to the range of substances encountered, as well as the methods by which fungal biodeterioration can be assessed and combated, and how certain fungal processes may be utilized in bioprotection.

Recolonization dynamics of marble monuments after cleaning treatments: A nine-year follow-up study

The prevention and control of biological patinas on outdoor stone monuments represent a demanding challenge for the conservation of cultural heritage also due to some microorganisms, particularly resistant to treatments, such as black meristematic fungi, an eco-physiological group well known for its tolerance to extreme conditions. Even if several methods and eco-friendly products have been proposed as new alternatives, traditional biocides are still far from being completely replaced. Recolonization is a natural process that occurs sooner or later after cleaning. The time that elapses until its occurrence can vary considerably depending on environmental conditions and the used products; unfortunately, the papers describing the effect of treatments over time are rare. This work aims to shed light on the recolonization process of marble surfaces in the ancient monumental cemetery of Bonaria (Cagliari) after nine years from treatments, evaluating the long-term efficiency of two different cleaning methods, namely dimethyl sulfoxide-based gel (DMSO-based gel) and Biotin T (a didecyldimethylammonium chloride-based product-). In this context, the microflora present before treatments and in the following years was assessed by culture-based methods and identified by molecular techniques, with attention on black meristematic fungi, which were used as reference for the most resistant lithobiontic organisms. Different environmental parameters, such as temperature, exposition, dominant winds, and rainfall, were considered, and infrared thermography, portable light microscopy, and image analysis were used. This research evidenced the influence of water availability and lightning in recolonization processes, the transition from the pioneer fungal community versus more resistant black fungal species after Biotin T treatment, and the long-lasting efficiency of the DMSO-based gel. These findings prove that this low-impact method deserves more attention in the conservation of outdoor marble monuments, emphasizing the importance of long-term studies.

The Metallotolerance and Biosorption of As(V) and Cr(VI) by Black Fungi

A collection of 34 melanized fungi isolated previously from anthropogenic contaminated sites were assessed for their tolerance to toxic concentrations of As(V) and Cr(VI) anions. Three strains of the species Cyphellophora olivacea, Rhinocladiella similis, and Exophiala mesophila (Chaetothyriales) were identified as hyper-metallotolerant, with estimated IC50 values that ranged from 11.2 to 16.9 g L-1 for As(V) and from 2.0 to 3.4 g L-1 for Cr(VI). E. mesophila and R. similis were selected for subsequent assays on their biosorption capacity and kinetics under different pH values (4.0 and 6.5) and types of biomass (active and dead cells and melanin extracts). The fungal biosorption of As(V) was relatively ineffective, but significant removal of Cr(VI) was observed from liquid cultures. The Langmuir model with second-order kinetics showed maximum sorption capacities of 39.81 mg Cr6+ g-1 for R. similis and 95.26 mg Cr6+ g-1 for E. mesophila on a dry matter basis, respectively, while the kinetic constant for these two fungi was 1.32 × 10-6 and 1.39 × 10-7 g (mg Cr6+ min)-1. Similar experiments with melanin extracts of E. mesophila showed maximum sorption capacities of 544.84 mg Cr6+ g-1 and a kinetic constant of 1.67 × 10-6 g (mg Cr6+ min)-1. These results were compared to bibliographic data, suggesting that metallotolerance in black fungi might be the result of an outer cell-wall barrier to reduce the diffusion of toxic metals into the cytoplasm, as well as the inner cell wall biosorption of leaked metals by melanin.

The Roman Houses of the Caelian Hill (Rome, Italy): Multitemporal Evaluation of Biodeterioration Patterns

Like other hypogeal environments, the Roman Houses of the Caelian Hill are prone to unwanted biological growth. Wide conservative interventions have been carried out at the beginning of this millenium to reduce biodeterioration and physical-chemical damages. Retracing the last monitoring work, we assessed the site's current state of conservation and biodeterioration intending to check the previous treatments' effectiveness and deepen the common knowledge of the subterranean biota and their possible biodeteriogenic effects. Starting from the past test areas and the previous identifications of the occurring biodeteriogens, we further isolated and identified the main eubacterial, fungal, and phototrophic settlers, focusing on some detrimental traits for wall paintings (i.e., acid production and carbonate precipitation). The achieved results proved the success of the performed interventions in reducing the wall's water content. Otherwise, the new conditions raise, in the long term, new concerns about lampenflora, carbonate precipitations, and salt efflorescence. Here, the Caelian Houses' new status is documented. The possible favouring conditions for the different groups of biodeteriogens, along with the taxonomical novelties, additional risks tied to the anthropization of the resident culturable microbial community, and the possible relation between the black fungus Cyphellophora olivacea and roots, are reported and discussed.

Characterization of the Community of Black Meristematic Fungi Inhabiting the External White Marble of the Florence Cathedral

Meristematic black fungi are a highly damaging group of microorganisms responsible for the deterioration of outdoor exposed monuments. Their resilience to various stresses poses significant challenges for removal efforts. This study focuses on the community of meristematic fungi inhabiting the external white marble of the Cathedral of Santa Maria del Fiore, where they contribute to its darkening. Twenty-four strains were isolated from two differently exposed sites of the Cathedral, and their characterization was conducted. Phylogenetic analysis using ITS and LSU rDNA regions revealed a wide diversity of rock-inhabiting fungal strains within the sampled areas. Eight strains, belonging to different genera, were also tested for thermal preferences, salt tolerance, and acid production to investigate their tolerance to environmental stressors and their interaction with stone. All tested strains were able to grow in the range of 5-30 °C, in the presence 5% NaCl, and seven out of eight strains were positive for the production of acid. Their sensitivities to essential oils of thyme and oregano and to the commercial biocide Biotin T were also tested. The essential oils were found to be the most effective against black fungi growth, indicating the possibility of developing a treatment with a low environmental impact.

Exploring Differences in Culturable Fungal Diversity Using Standard Freezing Incubation-A Case Study in the Limestones of Lemos Pantheon (Portugal)

In this study, we explored the biodiversity and abundance of culturable fungi in four samples associated with different biodeterioration outlines collected from the Lemos Pantheon, a limestone-built artwork in Portugal. We compared the results from prolonged standard freezing with those previously obtained from fresh samples to analyze differences in the obtained community and assess the effectiveness of the standard freezing incubation protocol in uncovering a different segment of culturable fungal diversity. Our results showed a slight decrease in culturable diversity, but over 70% of the obtained isolates were not present in the previously studied fresh samples. We also identified a high number of potential new species with this procedure. Moreover, the use of a wide variety of selective culture media positively influenced the diversity of the cultivable fungi obtained in this study. These findings highlight the importance of developing new protocols under varying conditions to accurately characterize the culturable fraction in a given sample. The identification and study of these communities and their possible contribution to the biodeterioration process is crucial knowledge for formulating effective conservation and restoration plans to prevent further damage to valuable cultural heritage assets.

Unraveling disparate roles of organisms, from plants to bacteria, and viruses on built cultural heritage

The different organisms, ranging from plants to bacteria, and viruses that dwell on built cultural heritage can be passive or active participants in conservation processes. For the active participants, particular attention is generally given to organisms that play a positive role in bioprotection, bioprecipitation, bioconsolidation, bioremediation, biocleaning, and biological control and to those involved in providing ecosystem services, such as reducing temperature, pollution, and noise in urban areas. The organisms can also evolve or mutate in response to changes, becoming tolerant and resistant to biocidal treatments or acquiring certain capacities, such as water repellency or resistance to ultraviolet radiation. Our understanding of the capacities and roles of these active organisms is constantly evolving as bioprotection/biodeterioration, and biotreatment studies are conducted and new techniques for characterizing species are developed. This brief review article aims to shed light on interesting research that has been abandoned as well as on recent (some ongoing) studies opening up new scopes of research involving a wide variety of organisms and viruses, which are likely to receive more attention in the coming years. KEY POINTS: • Organisms and viruses can be active or passive players in heritage conservation • Biotreatment and ecosystem service studies involving organisms and viruses are shown • Green deal, health, ecosystem services, and global change may shape future research.

Knufia obscura sp. nov. and Knufia victoriae sp. nov., two new species from extreme environments

Six strains of black meristematic fungi were isolated from Antarctic soils, gasoline car tanks and from the marine alga Flabellia petiolata. These fungi were characterized by morphological, physiological and phylogenetic analyses. According to the maximum-likelihood analysis reconstructed with ITS and LSU sequences, these strains belonged to the genus Knufia. Knufia obscura sp. nov. (holotype CBS 148926) and Knufia victoriae sp. nov. (holotype CBS 149015) are proposed as two novel species and descriptions of their morphological, physiological and phylogenetic features are presented. Based on the maximum-likelihood analyses, K. obscura was closely related to Knufia hypolithi (99 % bootstrap support), while K. victoriae clustered in the clade of Knufia cryptophialidica and Knufia perfecta (93 % bootstrap support). Knufia victoriae, recorded in Antarctic soil samples, had a psychrophilic behaviour, with optimal growth between 10 and 15 °C and no growth recorded at 20 °C. Knufia obscura, from a gasoline car tank and algae, displayed optimal growth between 20 and 25 °C and was more tolerant to salinity than K. victoriae.

Circumfusicillium cavernae gen. et sp. nov. (Bionectriaceae, Hypocreales) Isolated from a Hypogean Roman Cryptoporticus

Stone monuments and relics are prone to biodeterioration processes prompted by microbial proliferation and activity. Among the distinct microbes capable of stone colonization, fungi are known to strongly contribute to stone biodeterioration. During the ongoing efforts aiming to study fungi thriving in dolomitic limestone walls of the Coimbra’s hypogean Roman cryptoporticus (Portugal), two unknown Bionectriaceae isolates were retrieved. The aim of this work was to depict the molecular and phenotypic characteristics of these microorganisms. The phylogenetic analyses revealed that the studied strains could not be assigned to any of the currently known Bionectriaceae genera. Moreover, the isolates exhibited distinctive and peculiar characteristics, such as the packing of conidia by surrounding hyphal segments and the formation of rope-like microsclerotia with a textura globose. Taking into account all the data obtained, a novel genus and species, Circumfusicillium cavernae gen. et sp. nov. in Bionectriaceae (Hypocreales), is proposed here.

The Susceptibility to Biodegradation of Some Consolidants Used in the Restoration of Mural Paintings

This study evaluated both the possible fungal metabolites involved in the degradation of the commercial consolidant known as Paraloid® B72 and the national artisanal consolidant named transparent dispersion of casein and the deteriorative potential of melanised fungi. Fungi were found to have the capacity to produce organic acids, proteases and esterases when they grow on consolidants, which can be used as nutrients. Mycelia produced by melanised fungi affected the appearance, as well as the integrity, of consolidants applied on painted experimental models and fragments of frescoes. In treatment trials with biocides (Biotin R®, Biotin T® and Preventol® RI 80), the morphology of the consolidants, as well as the vitality of the fungi, were assessed 30 days after the inoculation with melanic fungi. Direct observation, optical microscopy, colourimetry and microbiological analysis highlighted the degradation of the consolidants by fungi and their acquired resistance after biocidal treatments. Biotin R® applied by brushing on the surface of the consolidants proved to be the most effective treatment, followed by Biotin T®. Considering the overall results for both Paraloid® B72 and transparent dispersion of casein, use of Biotin R® applied by brushing is recommended for preventive conservation.

Phototrophic and fungal communities inhabiting the Roman cryptoporticus of the national museum Machado de Castro (UNESCO site, Coimbra, Portugal)

Caves are oligotrophic environments, characterized by constant temperatures, high humidity and low natural light. However, microbial shifts can still happen in such environments, especially with the increase in tourist activity and implementation of artificial lights, making caves even more susceptible to environmental changes. As a result, proliferation of phototrophic organisms can increase dramatically, leading to their settlement on stone surfaces, which in turn facilitates the development of heterotrophic organisms, such as fungi and bacteria. The Roman Cryptoporticus of the National Museum Machado de Castro, erected by the Romans in the 1st or second century, is one of the most emblematic buildings in the city of Coimbra. However, the majority of the rooms that constitute this monument show signs of biodeterioration by microalgae and cyanobacteria as well as of fungi. The aim of this study was to characterize the phototrophic and fungal communities at this site, employing culture-dependent and-independent methodologies. Culture-dependent results showed that the phototrophic communities were mainly composed of green microalgae, whereas the culture-independent showed that cyanobacteria were the most dominant. As to the fungal communities, both approaches identified various entomopathogenic fungal species. In addition, the culture-independent analysis also allowed to verify the presence of animal reads, suggesting the hypothesis that animal vectored dispersion can play an important role in the development of fungi at this environment.

Black Fungi on Stone-Built Heritage: Current Knowledge and Future Outlook

Black fungi are considered as one of the main group of microorganisms responsible for the biodeterioration of stone cultural heritage artifacts. In this paper, we provide a critical analysis and review of more than 30 years of studies on black fungi isolated from stone-built heritage from 1990 to date. More than 109 papers concerning the fungal biodeterioration activity of stone were analysed. The main findings were a check list of the black fungal taxa involved in the biodeterioration of stone-built heritage, with a particular reference to meristematic black fungi, the main biodeterioration pattern attributed to them, and the methods of study including the new molecular advances. A particular focus was to discuss the current approaches to control black fungi from stone-built heritage and future perspectives. Black fungi are notoriously hard to remove or mitigate, so new methods of study and of control are needed, but it is also important to combine classical methods with new approaches to improve current knowledge to implement future conservation strategies.

Fungi Affecting Wall Paintings of Historical Value: A Worldwide Meta-Analysis of Their Detected Diversity

Wall paintings have been a cultural expression of human creativity throughout history. Their degradation or destruction represents a loss to the world’s cultural heritage, and fungi have been identified as a major contributor to their decay. We provide a critical review of fungi isolated from worldwide wall paintings between 1961–2021. One-hundred three scientific papers were reviewed focusing on fungal diversity, isolation protocols, and spatial distribution of data. The study sites were grouped into five environmental categories on the basis of the expected major microclimatic conditions (temperature, relative humidity, ventilation), and the possible relationship with the species found was investigated. The highest number of records were localized in Europe, with 38 sites on a total of 74, 20 of which were from Italy. A total of 378 fungal entries were obtained, consisting of 1209 records, belonging to 260 different species and 173 genera. The accuracy level in taxa determination was highly variable among different papers analyzed. Data showed a dominance of Ascomycota, mainly of orders Eurotiales and Hypocreales probably due to their wide distribution and easily air dispersed spores and due to the possible pitfalls linked to the isolation methods, favoring rapidly growing taxa. Statistical analyses revealed that fungal communities were not strictly linked to environmental categories with different ventilation, temperature, and humidity. Such findings may be due to the wide geographical area, the wide heterogeneity of the data, and/or the absence of standardized sampling and analyses protocols. They could also be the result of the dominance of some prevailing factors in the various sites that mask the influence one of each other.

Black Fungi and Stone Heritage Conservation: Ecological and Metabolic Assays for Evaluating Colonization Potential and Responses to Traditional Biocides

Identifying species involved in biodeterioration processes is helpful, however further effort is needed to assess their ecological requirements and actual activity. Black fungi (BF) represent one of the most underestimated threats to stone cultural heritage in the Mediterranean basin; they are difficult to kill or remove due to their ability to grow inside the rock and cope with several stresses. Despite this, little is known about BF and factors favoring their growth on stone surfaces. Eighteen BF species were here investigated for temperature and salt tolerance, and metabolic traits by plate assays. The relation between some highly damaged monuments and their BF settlers was assessed using X-ray diffraction analysis, mercury intrusion porosimetry, and SEM. The sensitiveness to four commonly used traditional biocides was also tested. All strains were able to grow within the range of 5–25 °C and in the presence of 3.5% NaCl. Instrumental analyses were fundamental in discovering the relation between halophilic strains and weathered marble sculptures. The acid, cellulase, esterase, and protease production recorded proved BF’s potential to produce a chemical action on carbonate stones and likely affect other materials/historical artefacts. Besides, the use of carboxymethylcellulose and Tween 20 should be evaluated in restoration practice to prevent tertiary bioreceptivity. Agar diffusion tests helped identify the most resistant species to biocides, opening the perspective of its use as reference organisms in material testing procedures.

Diagnostics and Monitoring to Preserve a Hypogeum Site: The Case of the Mithraeum of Marino Laziale (Rome)

Conservation of hypogea and their accessibility by the visitors is a hard question, due to the interaction of different factors such as the intrinsic characteristics of the hypogeal environments and the presence of public. A particular case is represented by the Mithraeum of Marino Laziale, located a few kilometers away from Rome and accidentally discovered in the 1960s. The uniqueness of the discovery was the presence of a well-preserved painting of the Mithraic scene (II century A.D.) probably due to the oblivion of the place of worship over the centuries as well as the isolation from the outdoor environment. Unfortunately, despite a recent complete restoration and recovery of the archaeological area, which ended in 2015, the area was never open to the visitors and only two years after completing the works it was no longer safe to use. Hence, the need for a new planning of interventions starting from the deep knowledge of this cultural heritage and from the analysis of past incorrect actions to arrive at the opening—without any risk for the archaeological findings and visitors—and management of this site, never exposed to the public. Therefore, since 2018 a diagnostic campaign and microclimate monitoring have been started. The data collected during the two years of investigations have been fundamental to assess the conservation state of the hypogeal environment and the potential risks for the preservation of the three paintings (the Mithraic scene and two dadophores). Long-term monitoring of indoor environmental conditions assumes the role of an essential tool for the planning of preventive conservation strategies but also for the control of the site after its opening to the visitors. Furthermore, the characterization of the microclimate is non-invasive, sufficiently economical and accurate. In this paper, the characterization of surfaces in the Mithraic gallery through optical microscopy, UV fluorescence/imaging techniques, FT-IR spectroscopy, XRD and the microclimatic parameters variation in the presence or absence of visitors are used to define the strategies for the opening and fruition of the Mithraeum. The strategies for the sustainable fruition of this unique archaeological site have been defined through a conservation protocol approved by the Italian Ministry of Cultural Heritage and necessary for the site managers and curators of the Municipality of Marino Laziale to finally support its opening.

Geochemical-Microscopical Characterization of the Deterioration of Stone Surfaces in the Cloister of Santa Maria in Vado (Ferrara, Italy)

Santa Maria in Vado is a monument in the rich artistic heritage of the city of Ferrara (north of Italy). In this paper we want to investigate the state of conservation of tombstones, cloister and the entrance to the basilica, in order to keep them in the best possible state for the future generations. From the chemical characterization, the state of conservation was determined focusing on the biodeteriogenic and non-biodeteriogenic factors, which determine a series of unwanted changes in the physical, mechanical and above all aesthetic properties of the material, often closely connected with the environment and conservation conditions. On the macroscopic observation, the state of conservation of the tombstones appeared to be very deteriorated through aesthetic and structural damage. In detail, the stereo microscope observation of samples collected from the tombstones show the presence of efflorescence probably caused by the abundant of water that bring the salts present inside the rock into solution. Relating the columns, μ-XRF analysis confirm the carbonate composition of samples and presence of iron and sulfur. Finally, SEM observation highlighted the presence of black crust on arch samples and the presence of pollen on the black crust and spheroidal particles probably related to atmospheric pollution.

Hydrocarbon-Contaminated Sites: Is There Something More Than Exophiala xenobiotica? New Insights into Black Fungal Diversity Using the Long Cold Incubation Method

Human-made hydrocarbon-rich environments are important reservoirs of microorganisms with specific degrading abilities and pathogenic potential. In particular, black fungi are of great interest, but their presence in the environment is frequently underestimated because they are difficult to isolate. In the frame of a biodiversity study from fuel-contaminated sites involving 30 diesel car tanks and 112 fuel pump dispensers (52 diesel and 60 gasoline, respectively), a total of 181 black fungal strains were isolated. The long cold incubation (LCI) of water-suspended samples, followed by plating on Dichloran Rose Bengal Chloramphenicol Agar (DRBC), gave isolation yields up to six times (6.6) higher than those of direct plating on DRBC, and those of enrichment with a phenolic mix. The sequencing of ITS and LSU-rDNA confirmed the dominance of potentially pathogenic fungi from the family Herpotrichiellaceae and Exophiala xenobiotica. Moreover, other opportunistic species were found, including E. opportunistica, E. oligosperma, E. phaeomuriformis, and Rhinocladiella similis. The recurrent presence of E. crusticola, Knufia epidermidis, Aureobasidium melanogenum, Cladosporium spp., and Scolecobasidium spp. was also recorded. Interestingly, 12% of total isolates, corresponding to 50% of taxa found (16/32), represent new species. All the novel taxa in this study were isolated by LCI. These findings suggest that black fungal diversity in hydrocarbon-rich niches remains largely unexplored and that LCI can be an efficient tool for further investigations.

Biodeterioration of Salón de Reinos, Museo Nacional del Prado, Madrid, Spain

The Salón de Reinos, a remnant of the 17th century Palacio del Buen Retiro, was built as a recreational residence under the reign of Felipe IV between 1632 and 1640 and was the main room for the monarch’s receptions. This Salón owes its name to the fact that the coats of arms (shields) of the 24 kingdoms that formed Spain in Felipe IV’s time were painted on the vault, above the windows. In addition, the ceiling shows an original decorative composition. The painted ceiling and window vaults showed deterioration evidenced by fissures, water filtration, detachments of the paint layer, and black stains denoting fungal colonization related to humidity. Ten strains of bacteria and 14 strains of fungi were isolated from the deteriorated paintings. Their biodeteriorative profiles were detected through plate assays. The most frequent metabolic functions were proteolytic and lipolytic activities. Other activities, such as the solubilization of gypsum and calcite and the production of acids, were infrequent among the isolates.

Plant DNA Barcode as a Tool for Root Identification in Hypogea: The Case of the Etruscan Tombs of Tarquinia (Central Italy)

Roots can produce mechanical and chemical alterations to building structures, especially in the case of underground historical artifacts. In archaeological sites, where vegetation plays the dual role of naturalistic relevance and potential threat, trees and bushes are under supervision. No customized measures can be taken against herbaceous plants lacking fast and reliable root identification methods that are useful to assess their dangerousness. In this study, we aimed to test the efficacy of DNA barcoding in identifying plant rootlets threatening the Etruscan tombs of the Necropolis of Tarquinia. As DNA barcode markers, we selected two sections of the genes rbcL and matK, the nuclear ribosomal internal transcribed spacer (nrITS), and the intergenic spacer psbA-trnH. All fourteen root samples were successfully sequenced and identified at species (92.9%) and genus level (7.01%) by GenBank matching and reference dataset implementation. Some eudicotyledons with taproots, such as Echium italicum L., Foeniculum vulgare Mill., and Reseda lutea L. subsp. lutea, showed a certain recurrence. Further investigations are needed to confirm this promising result, increasing the number of roots and enlarging the reference dataset with attention to meso-Mediterranean perennial herbaceous species. The finding of herbaceous plants roots at more than 3 m deep confirms their potential risk and underlines the importance of vegetation planning, monitoring, and management on archaeological sites.

Current Knowledge on the Fungal Degradation Abilities Profiled through Biodeteriorative Plate Essays

Fungi are known to contribute to the development of drastic biodeterioration of historical and valuable cultural heritage materials. Understandably, studies in this area are increasingly reliant on modern molecular biology techniques due to the enormous benefits they offer. However, classical culture dependent methodologies still offer the advantage of allowing fungal species biodeteriorative profiles to be studied in great detail. Both the essays available and the results concerning distinct fungal species biodeteriorative profiles obtained by amended plate essays, remain scattered and in need of a deep summarization. As such, the present work attempts to provide an overview of available options for this profiling, while also providing a summary of currently known fungal species putative biodeteriorative abilities solely obtained by the application of these methodologies. Consequently, this work also provides a series of checklists that can be helpful to microbiologists, restorers and conservation workers when attempting to safeguard cultural heritage materials worldwide from biodeterioration.

Vegetation Cover and Tumuli’s Shape as Affecting Factors of Microclimate and Biodeterioration Risk for the Conservation of Etruscan Tombs (Tarquinia, Italy)

The conservation of underground tombs is affected by several physical-chemical and biological factors, which could be reduced by insulating systems able to maintain the microclimatic stability also decreasing the biodeterioration risk. In Mediterranean areas, wild ephemeral plants, which reduce their cover during the hot season, seem unsuitable for reducing summer overheating. In this study, we wish to assess the influence of vegetation cover and of overlaying soil, after the establishment of an evergreen turf of a cultivar of Cynodon dactylon, on two tombs in the Etruscan Necropolis of Monterozzi, covered by linear-shaped tumuli. Therefore, we evaluated for 10 months the thermo-hygrometric values of these tombs, together with two tombs as controls. We also evaluated the different tumuli’s morphologies and the related received solar radiation. Results confirmed that late summer and early autumn as critical microclimatic periods for the risk factors of hypogeal paintings when peaks of superficial temperature occur. A positive influence of vegetation cover on maintaining constant humidity and internal temperatures was detected, but the mounds orientation, as well as soil depth, seems to have a relevant role. Considering the naturalistic features of the area and the related cultural ecosystem services, a careful selection of wild plants is suggested.