Search

Cave heritage is often threatened by tourism or even scientific activities, which can lead to irreversible deterioration. We present a preventive conservation monitoring protocol to protect caves with rock art, focusing on La Garma Cave (Spain), a World Heritage Site with valuable archaeological materials and Palaeolithic paintings. This study assessed the suitability of the cave for tourist use through continuous microclimate and airborne particles monitoring, biofilm analysis, aerobiological monitoring and experimental visits. Our findings indicate several factors that make it inadvisable to adapt the cave for tourist use. Human presence and transit within the cave cause cumulative effects on the temperature of environmentally very stable and fragile sectors and significant resuspension of particles from the cave sediments. These environmental perturbations represent severe impacts as they affect the natural aerodynamic control of airborne particles and determine bacterial dispersal throughout the cave. This monitoring protocol provides part of the evidence to design strategies for sustainable cave management.

European caves contain some of the world’s greatest Paleolithic paintings, and their conservation is at risk due to the use of artificial lighting. Both lighting and high CO2 promotes the growth of phototrophic organisms on walls, speleothems and ground sediments. In addition, the combined effect of increases in CO2, vapor concentration and temperature variations induced by visitors can directly affect the development of corrosion processes on the cave rock surfaces. An early detection of the occurrence of phototrophic biofilms on Paleolithic paintings is of the utmost importance, as well as knowing the microorganisms involved in the colonization of rocks and walls. Knowledge of the colonizing species and their ecology will allow the adoption of control measures. However, this is not always possible due to the limited amount of biomass available for molecular analyses. Here, we present an alternative approach to study faint green biofilms of Chlorophyta in the initial stage of colonization on the Polychrome Panel in El Castillo Cave, Cantabria, Spain. The study of the biofilms collected on the rock art panel and in the ground sediments revealed that the lighting of the cave promoted the development of the green algae Jenufa and Coccomyxa, as well as of complex prokaryotic and eukaryotic communities, including amoebae, their endoparasites and associated bacteria and fungi. The enrichment method used is proposed as a tool to overcome technical constraints in characterizing biofilms in the early stages, allowing a preliminary characterization before deciding for direct or indirect interventions in the cave.

El patrimonio natural y cultural de las cuevas se ve a menudo amenazado por el turismo y por otras actividades de carácter científico que las expone a riesgos que pueden provocar la alteración irreversible de sus condiciones ambientales de carácter irreversible. Las cuevas con arte rupestre y yacimientos arqueológicos suponen un caso especial y complejo. Cualquier modificación en sus condiciones climáticas conlleva un cambio en el ecosistema subterráneo que, a menudo, favorece el desarrollo y proliferación de poblaciones microbianas que llegan a colonizar los diferentes sustratos presentes en la cueva. La cueva de La Garma constituye un ejemplo destacado de cavidad con una larga frecuentación humana desde el Paleolítico antiguo hasta la Edad Media. Desde su descubrimiento en noviembre de 1995, la cueva sólo es accesible para la investigación arqueológica y la monitorización de sus condiciones ambientales. En este trabajo se presentan los resultados del estudio detallado de sus condiciones microclimáticas, y su influencia en la dispersión de microorganismos en el aire subterráneo y en el desarrollo de biofilms sobre la superficie de las rocas y los sedimentos. La dispersión bacteriana en el aire de la cueva está directamente influenciada por la circulación del aire, con fuertes incrementos durante los pulsos de ventilación vinculados a los vientos de componente sur en el exterior. Las conclusiones del estudio desaconsejan la adecuación de la cueva para su uso turístico y el control exhaustivo de cualquier trabajo arqueológico que implique perforaciones, zanjas o movimientos de tierras- sedimentos, ya que se favorecería la proliferación inmediata de colonias microbianas y con ello el desarrollo de procesos irreversibles de biodeterioro.

The aerobiology of caves in Southern Spain possesses special characteristics, different from caves located in Northern Spain. Previous studies demonstrated the influence of outdoor air on caves in the north and the existence of two different patterns, depending on the season. In summer there is an abundance of Ascomycota, whereas in winter Basidiomycota predominates, which are related to the periods of stagnation and ventilation, respectively. In caves in Southern Spain the presence of airborne Basidiomycota is scarce and Ascomycota represents the main group of fungi widely distributed across the caves in all seasons. The most characteristic features were the abundant presence of entomopathogenic fungi (Beauveria bassiana, Parengyodontium album, Pochonia chlamydosporia, Leptobacillium symbioticum, Leptobacillium leptobactrum) and Cladosporium cladosporioides in Cueva del Tesoro, Cueva de Ardales and Gruta de las Maravillas. However, the presence of yeasts of the genera Cutaneotrichosporon, Trichosporon, Cryptococcus, Naganishia, Cystobasidium, Microstroma and Phragmotaenium was exclusive to Gruta de las Maravillas. Fungal hazard in the three show caves were determined using an ecological indicator based on the concentration of spores in cave air. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.

Analytical pyrolysis is a tool widely used for investigating the nature of macromolecules. This technique has been applied with success for solving the chemical structure of geo- and biopolymers. However, with complex macromolecules, such as fungal melanins, analytical pyrolysis presents some drawbacks due to the fact that they rarely can be obtained in a pure grade and contains a mixture of polysaccharides, chitin, proteins, nucleic acids, and lipids, among other materials. Analytical pyrolysis permits the characterization of the compounds co-extracted or linked to the melanin. Nevertheless, our data revealed that under the conditions usually employed in the pyrolysis of melanins, the technique presented serious limitations due to the complex structure and diversity of components that suffer extensive thermal degradation through secondary reactions with the production of considerable number of artifacts. To the light of pyrolysis data, the melanin of Ochroconis spp. is not based on 3,4-dihydroxyphenylalanine (DOPA) or 1,8-dihydroxynaphthalene (DHN), and it is suggested that it could be a type of pyomelanin, based on the polymerization of homogentisic acid and other phenolic compounds.

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.

Research on cave microorganisms has mainly focused on the microbial communities thriving on speleothems, rocks and sediments; however, drip water bacteria and calcite precipitation has received less attention. In this study, microbial communities of carbonate precipitates from drip waters in Nerja, a show cave close to the sea in southeastern Spain, were investigated. We observed a pronounced difference in the bacterial composition of the precipitates, depending on the galleries and halls. The most abundant phylum in the precipitates of the halls close to the cave entrance was Proteobacteria, due to the low depth of this sector, the direct influence of a garden on the top soil and the infiltration of waters into the cave, as well as the abundance of members of the order Hyphomicrobiales, dispersing from plant roots, and other Betaproteobacteria and Gammaproteobacteria, common soil inhabitants. The influence of marine aerosols explained the presence of Marinobacter, Idiomarina, Thalassobaculum, Altererythrobacter and other bacteria due to the short distance from the cave to the sea. Nineteen out of forty six genera identified in the cave have been reported to precipitate carbonate and likely have a role in mineral deposition.

European caves contain some of the world¿s greatest Paleolithic paintings, and their conservation is at risk due to the use of artificial lighting. Both lighting and high CO2 promotes the growth of phototrophic organisms on walls, speleothems and ground sediments. In addition, the combined effect of increases in CO2, vapor concentration and temperature variations induced by visitors can directly affect the development of corrosion processes on the cave rock surfaces. An early detection of the occurrence of phototrophic biofilms on Paleolithic paintings is of the utmost importance, as well as knowing the microorganisms involved in the colonization of rocks and walls. Knowledge of the colonizing species and their ecology will allow the adoption of control measures. However, this is not always possible due to the limited amount of biomass available for molecular analyses. Here, we present an alternative approach to study faint green biofilms of Chlorophyta in the initial stage of colonization on the Polychrome Panel in El Castillo Cave, Cantabria, Spain. The study of the biofilms collected on the rock art panel and in the ground sediments revealed that the lighting of the cave promoted the development of the green algae Jenufa and Coccomyxa, as well as of complex prokaryotic and eukaryotic communities, including amoebae, their endoparasites and associated bacteria and fungi. The enrichment method used is proposed as a tool to overcome technical constraints in characterizing biofilms in the early stages, allowing a preliminary characterization before deciding for direct or indirect interventions in the cave.

Two Streptomyces strains, labeled as MZ03-37(T) and MZ03-48, were isolated from two different samples, a mucolite-type speleothem and a microbial mat on the walls of a lava tube from La Palma Island (Canary Islands). Phylogenetic analysis based on concatenated sequences of six housekeeping genes indicated that both strains belonged to the same species. The closest relatives for both strains were Streptomyces palmae CMU-AB204(T) (98.71%), Streptomyces catenulae NRRL B-2342(T) (98.35%), and Streptomyces ramulosus NRRL B-2714(T) (98.35%). Multi-locus sequence analysis (MLSA), based on five house-keeping gene alleles (i.e., atpD, gyrB, recA, rpoB, and trpB), indicated that both isolated strains were closely related to S. catenulae NRRL B-2342(T). Whole-genome average nucleotide identity (ANI) scores of both strains were in the threshold value for species delineation with the closest species. Both strains presented a G+C content of 72.1 mol%. MZ03-37(T) was light brown in substrate and white in aerial mycelium, whereas MZ03-48 developed a black aerial and substrate mycelium. No pigment diffusion was observed in both strains. They grew at 10 degrees C-37 degrees C (optimum 28 degrees C-32 degrees C) and in the presence of up to 15% (w/v) NaCl. MZ03-37(T) grew at pH 5-10 (optimal 6-9), whereas MZ03-48 grew at pH 4-11 (optimal 5-10). LL-Diaminopimelic acid was the main diamino acid identified. The predominant fatty acids in both strains were iso-C-16:0, anteiso-C-15:0, C-16:0, and iso-C-14:0. The major isoprenoid quinones were MK-9(H6) and MK-9(H8), and the main polar lipids were aminolipid, phospholipid, and phosphoglycolipid. In silico analyses for functional annotation predicted the presence of gene clusters involved in resistome mechanisms and in the synthesis of described antimicrobials such as linocin-M18 and curamycin, as well as different genes likely involved in mechanisms for active compound synthesis, both already described and not discovered so far. On the basis

Las cuevas vienen siendo estudiadas desde diversos puntos de vistas: ambiental, geológico, geoquímico, microbiológico, turístico, etc. Sin embargo, las cuevas y otros ambientes subterráneos han sido poco explorados desde el punto de vista biotecnológico, aunque representan nichos ecológicos indispensables que podrían ofrecer nuevas moléculas de interés para la medicina y la farmacología. Se han investigado las bacterias de diversas cuevas de la Península Ibérica, así como de las Islas Canarias para comprobar su bioactividad. Entre ellas, han mostrado un interesante potencial antimicrobiano algunas de las bacterias aisladas de la Cueva de Altamira. Los análisis in vitro e in silico mostraron la inhibición de bacterias patógenas Gram- positivas, Gram-negativas y hongos. El interés de esta investigación se apoya en la conocida resistencia de las bacterias patógenas a los antimicrobianos, lo que se ha convertido en un problema mundial en las últimas décadas. Nuestros datos muestran la presencia de bacterias productoras de compuestos antimicrobianos en ambientes subterráneos; y el estudio de sus genomas indicarían la existencia de genes implicados en la síntesis de nuevos compuestos. Palabras clave: Cueva de Altamira, compuestos antimicrobianos, Crossiella, Pseudomonas, predicción de genes.

Morgana Cave is located in Val di Scerscen, Central Italian Alps. The cave opens at an altitude of 2,600 m a.s.l. close to the retreating glacier Vedretto di Scerscen, and its entrance was discovered 30 years ago hidden underneath the glacier. A characteristic of this cave is the occurrence of vermiculation deposits on the walls and ceiling. In general, the composition of the microbial communities in cave vermiculations is relatively unknown and rarely investigated. Here we present the data of a geomicrobiological study of vermiculations from an Alpine cave subjected to extreme climate conditions. The microbial communities were dominated by 13 main phyla of Bacteria, and contained a negligible percentage (<1%) of Archaea. The two major bacterial classes were Gammaproteobacteria and Betaproteobacteria, whose metabolic traits were mainly associated with the nitrogen cycle. In addition, psychrophilic and methanotrophic bacterial groups were identified. The occurrence of a large number of uncultured members, at the lowest taxonomic ranks, indicated the presence of still unexplored microbial taxa in the vermiculations.

Two Streptomyces strains were isolated from a lava tube in La Palma, Canary Islands. Genomic analyses suggest that the two strains could belong to the same species. Here, we report the draft genomes for these bacterial strains.

Etruscan and Roman necropolises are cemeteries with different types of burial practices, which are remarkable for their magnificent mural paintings. The conservation of these paintings is difficult, mainly derived from environmental factors and the opening of the tombs to public visits. One of the most complex phenomena observed on these sites is biodeterioration. The Circular Mausoleum tomb (Roman Necropolis of Carmona, Seville, Spain) is characterized by a heavy colonization of phototrophic microorganisms on the walls and ceiling. In addition, some areas near the ceiling exhibited an important number of violet stains of unknown origin. Previously, Agarossi (1994) found similar violet stains, attributed to streptomycetes, in two Etruscan tombs. However, no data on the species involved or the chemical structure of the pigments were reported. Here we show that the violet stains observed in the Circular Mausoleum are produced by a strain of the actinobacterium Streptomyces isolated from the mortar walls, and able to synthesize the same violet pigment in the laboratory. Streptomyces parvus MC05 was identified after whole genome study by means of Next Generation Sequencing methods. Pairwise comparisons carried out for genomes of the type strain of S. parvus DSM40348T and the MC05 strain were performed using Jspecies service. While results observed for ANIb, ANIm and Tetra indexes indicated that both strains belong to the same species, the S. parvus MC05 strain differs from the DSM20348T type strain in genome size and secondary metabolites production. AntiSMASH analysis implemented for both strains showed that the S. parvus MC05, isolated from the tomb, presents the capacity of synthesize bioactive compounds which were absents in the type strain. HPLC-MS of the culture extracts from S. parvus MC05 showed the production of three main granaticin derivatives (dihydrogranaticin A, granaticin A and granaticin B) in addition to minor products of other granaticin analogues. Gra, References - Agarossi, G. 1994. In Studi e Ricerche sulla Conservazione delle Opere d’Arte Dedicati alla Memoria di Marcello - Paribeni. F. Guidobaldi (ed.), CNRS, pp. 1−11. - Dominguez-Moñino, I. et al. 2017. Science of the Total Environment 598, 889-899.

This work presents a study on the airborne bacteria recorded in three Andalusian show caves, subjected to different managements. The main differences within the caves were the absence of lighting and phototrophic biofilms in Cueva de Ardales, the periodic maintenance and low occurrence of phototrophic biofilms in Gruta de las Maravillas, and the abundance of phototrophic biofilms in speleothems and walls in Cueva del Tesoro. These factors conditioned the diversity of bacteria in the caves and therefore there are large differences among the CFU m, determined using a suction impact collector, equipment widely used in aerobiological studies. The study of the bacterial diversity, inside and outside the caves, indicates that the air is mostly populated by bacteria thriving in the subterranean environment. In addition, the diversity seems to be related with the presence of abundant phototrophic biofilms, but not with the number of visitors received by each cave.

Cyanobacteria and microalgae are usually found in speleothems, rocks and walls of show caves exposed to artificial lighting. These microorganisms develop as biofilms coating the mineral surfaces and producing aesthetic, physical and chemical deterioration. A wide number of physical, chemical and environmental-friendly methods have been used for controlling the biofilms with different results. Natural biological control has been suggested by some authors as a theoretical approach but without direct evidence or application. Here we report the finding of a natural biological control of phototrophic biofilms on the speleothems of Nerja Cave, Malaga, Spain. The formation of plaques or spots where the phototrophic microorganisms disappeared can be assumed on the basis of processes of predation of bacteria, amoebas and some other organisms on the phototrophic biofilms. This study aims at investigating the potentialities of the biological control of phototrophic biofilms in caves, but the originality of these data should be confirmed in future studies with a larger number of biofilm samples in different ecological scenarios.

From the seminal studies about the problems of conservation of Vazquez Diaz’s mural paintings “Poema del Descubrimiento”, during the final 1970’s until today, the research trajectory of Cesáreo Sáiz Jiménez encompasses almost 40 years of continuous effort addressed to understand and help in the conservation of Cultural assets, especially of built heritage (historic buildings and monuments as well as archaeological sites) and subterranean heritage (with an especial dedication to caves, with or without rock art, and subterranean necropolis). This long and continuously updated research trajectory reached multiple goals, as could be the assessment of deterioration processes, the description of new species of microorganisms for the science, or the rendez-vous of different research groups by means of multiple collaborative initiatives. In the meantime, he also contributed to the formation of a human capital that integrated a multidisciplinary research group, continuously enriched by different approaches and techniques. The purpose of this contribution is to enlighten the role of Dr. Sáiz Jiménez along almost four decades dedicated to the applied investigation on the conservation of Cultural Heritage.

Subsurface granitic environments are scarce and poorly investigated. A multi‐disciplinary approach was used to characterize the abundant moonmilk deposits and associated microbial communities coating the granite walls of the 16th Century Paranhos spring water tunnel in Porto city (north‐west Portugal). It is possible that this study is the first record of moonmilk in an urban subsurface granitic environment. The morphology and texture, mineralogical composition, stable isotope composition and microbial diversity of moonmilk deposits have been studied to infer the processes of moonmilk formation. These whitish secondary mineral deposits are composed of very fine needle‐fibre calcite crystals with different morphologies and density. Calcified filaments of fungal hyphae or bacteria were distinguished by field emission scanning electron microscopy. Stable isotope analysis revealed a meteoric origin of the needle‐fibre calcite, with an important contribution of atmospheric CO2, soil respiration and urn:x-wiley:00370746:media:sed12431:sed12431-math-0001 from weathering of Ca‐bearing minerals. The DNA‐based analyses revealed the presence of micro‐organisms related to urban contamination, including Actinobacteria, mainly represented by Pseudonocardia hispaniensis, Thaumarchaeota and Ascomycota, dominated by Cladosporium. This microbial composition is consistent with groundwater pollution and contamination sources of the overlying urban area, including garages, petrol stations and wastewater pipeline leakage, showing that the Paranhos tunnel is greatly perturbed by anthropogenic activities. Whether the identified micro‐organisms are involved in the formation of the needle‐fibre calcite or not is difficult to demonstrate, but this study evidenced both abiotic and biogenic genesis for the calcite moonmilk in this subsurface granitic environment.

Two Gram-positive, catalase-positive, oxidase-negative, motile, endospore-forming, rod-shaped bacteria, designated as 0911MAR22V3T and 0911TES10J4, were isolated from air samples collected in two show caves, located in Andalusia, Southern Spain. Phylogenetic analysis based on 16S rRNA gene sequences indicated that both strains were indistinguishable and they were most closely related to Bacillus humi DSM 16318T (98%). DNA-DNA hybridization values of the strain 0911MAR22V3T with respect to strain 0911TES10J4 and B. humi DSM 16318T were 76.8% (73.9%, reciprocal) and 56.9% (63.3%, reciprocal analysis), respectively. Whole genome average nucleotide identity (ANI) values of both strains were in the threshold value for species delineation and less than 85% with B. humi. Strains 0911MAR22V3T and 0911TES10J4 grew at 10-47. °C (optimum 37. °C), at pH 6-9.5 and with 0-8% (w/v) NaCl (optimum 1%). In both strains the dominant isoprenoid quinone was MK-7, the major cellular polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, and two more phospholipids, the predominant fatty acids were iso-C15:0 and anteiso-C15:0 and the DNA G + C content was 38. mol%. On the basis of their phylogenetic relatedness and their phenotypic and genotypic features, the strains 0911MAR22V3T and 0911TES10J4 should be attributed to a novel species within the genus Bacillus, for which the name Bacillus onubensis sp. nov. is proposed. The type strain is 0911MAR22V3T (=LMG 27963T = CECT 8479T); and strain 0911TES10J4 (CECT 8478) is a reference strain.

The first tomb of a Roman Necropolis in the area of Carmona (Seville, Spain) was accidentally discovered in 1830. Few more tombs were exhumed between 1868 and 1869. These tombs were plundered until the beginning of the archaeological excavations in 1882. This necropolis, located in the town of Carmona, represents one of the most significant Roman burial sites in Southern Spain, and was in use during the 1st and 2nd centuries AD. Initially, the necropolis was used as quarry from which stone blocks were extracted and used for building construction. The quarry was then abandoned and reused as necropolis due to the workability of the rock. The Necropolis has suffered numerous and extensive interventions since its discovery. The first one was the adaptation of the necropolis for visits in 1885, including the construction of a trail, design of gardens around the tombs and plantation of trees. Nowadays, the gardens are considered one of the most deteriorating factors affecting the conservation of the tombs due to irrigation and consequent percolation of water inside the tombs, in addition to the damage caused by roots. Taking into account the cultural, artistic and religious importance of the Necropolis of Carmona, its preservation and conservation are a major issue, both from cultural and economic points of view. This importance emphasizes the need to define accurate and sustainable intervention protocols based on a deep understanding of the environmental and/or anthropogenic-induced deterioration processes. The design of effective preservation and/or conservation strategies should be based on exhaustive in situ surveys and laboratory investigations. Here we review 10 years of research in the Necropolis and we focus on the Circular mausoleum, as a case study, including an assessment of its conservation state, and the identification of the main deteriorating agents. In addition, an intervention proposal for the preservation of the Circular Mausoleum was presented.

Two novel species of the fungal genus Ochroconis, O. lascauxensis and O. anomala have been isolated from the walls of the Lascaux Cave, France. The interest in these fungi and their melanins lies in the formation of black stains on the walls and rock art which threatens the integrity of the paintings. Here we report solid-state cross polarization magic-angle spinning 13C and 15N nuclear magnetic resonance (NMR) spectroscopy and surface-enhanced Raman spectroscopy (SERS) of the melanins extracted from the mycelia of O. lascauxensis and O. anomala in order to known their chemical structure. The melanins from these two species were compared with those from other fungi. The melanins from the Ochroconis species have similar SERS and 13C and 15N NMR spectra. Their chemical structures as suggested by the data are not related to 3,4-dihydroxyphenylalanine, 5,6-dihydroxyindole or 1,8-dihydroxynaphthalene precursors and likely the building blocks from the melanins have to be based on other phenols that react with the N-terminal amino acid of proteins. The analytical pyrolysis of the acid hydrolysed melanin from O. lascauxensis supports this assumption.

From the seminal studies about the problems of conservation of Vazquez Diaz’s mural paintings “Poema del Descubrimiento”, during the final 1970’s until today, the research trajectory of Cesáreo Sáiz Jiménez encompasses almost 40 years of continuous effort addressed to understand and help in the conservation of Cultural assets, especially of built heritage (historic buildings and monuments as well as archaeological sites) and subterranean heritage (with an especial dedication to caves, with or without rock art, and subterranean necropolis). This long and continuously updated research trajectory reached multiple goals, as could be the assessment of deterioration processes, the description of new species of microorganisms for the science, or the rendez-vous of different research groups by means of multiple collaborative initiatives. In the meantime, he also contributed to the formation of a human capital that integrated a multidisciplinary research group, continuously enriched by different approaches and techniques. The purpose of this contribution is to enlighten the role of Dr. Sáiz Jiménez along almost four decades dedicated to the applied investigation on the conservation of Cultural Heritage.

El estudio aerobiológico de tres cuevas andaluzas: Cueva de Ardales (Málaga), Cueva del Tesoro (Rincón de la Victoria, Málaga) y Gruta de las Maravillas (Aracena, Huelva). Estas tres cuevas fueron elegidas en función del número de visitas anuales que recibían, como cueva poco visitada (Ardales), muy visitada (Aracena) y con un número de visitantes intermedio (Rincón de la Victoria). Estas cuevas albergan valores especiales: cultural (Cueva de Ardales y Cueva del Tesoro, con importantes testimonios de arte rupestre paleolítico y postpaleolítico), y geológico (Gruta de las Maravillas, que presenta una especial variedad y riqueza de espeleotemas; y El Tesoro, cuya historia geológica única muestra los efectos del modelado kárstico y de la erosión marina en fases sucesivas). El estudio comparativo de las bacterias y hongos del aire de estas cuevas ha permitido establecer una pauta de estacionalidad en las concentraciones fúngicas, relacionables con los períodos de mayor afluencia de visitantes y de mayor actividad de los artrópodos, así como detectar también la existencia de una pauta estacional en las concentraciones bacterianas, si bien en épocas diferentes en las distintas cuevas. De manera general se ha podido relacionar la concentración de bacterias y hongos en el aire con la mayor o menor presencia de visitantes, la ubicuidad de la especie Micrococcus yunannensis en el aire de estos ambientes subterráneos, la presencia de un perfil común de hongos entomógenos en las tres cuevas y la presencia de microorganismos potencialmente patógenos para los humanos, en especial para las personas inmunodeprimidas o de corta y avanzada edad. El trabajo ha permitido, además, proponer la descripción de cuatro nuevas especies para la ciencia, dos de ellas encuadrables en el género Bacillus y otras dos en el género Paracoccus.

Cave tourism represents the main threat for caves and for their conservation. Visitors cause important change in the microclimate and introduce organic carbon and microorganisms into caves. The visitors leave behind skin cells, hair, soil trapped on shoe soles and occasionally vomit, faeces and urine. Recently we faced a new human impact on show caves: chewing gum stuck to the wall. We have found chewing gum on the walls of Cueva del Tesoro, Rincón de la Victoria, Málaga, Spain. The bacteria colonizing the chewing gum were represented by members of Actinobacteria, Alphaproteobacteria and Firmicutes while the fungi were members of the Ascomycota, order Eurotiadles and Hypocreales. From the bacteria, the isolation of Brachybacterirum fresconis, Microbacterium aerolatum, Sphingopyxis italic and Bacillus litoralis wre noteworthy as were the presence of Aspergillus, Fusarium and Penicillium species form the fungi.

Paranhos constitutes one of the main water galleries excavated in the granite substratum of Porto City (Portugal) to gather the groundwater for public use during the past five centuries. This gallery is a Subterranean Cultural Heritage site with a potential use for underground geotourism under safe conditions. An environmental monitoring programme has been conducte in the site comprising rapid multi-parameters. This programme has allowed the identification of urban-induced causes of contamination of the aquifer and internal tunnel atmosphere (waste-water and gas leakage). This study has also comprised the determination of effective radioactive dose in different sectors of the tunnel for potential visitors based on 222Rn studies.

The altarpiece of the Seville Cathedral was built between 1481 and 1565 and has a total perimeter of 20.10 m and 23.41 m height, which makes this altarpiece the largest in the world. The last restoration was performed in 1977, centered on ensuring its structural stability and consolidation of wood structures and polychromy. A new intervention to appraise the state of conservation is currently in progress. Our study is centered on the assessment of the dust accumulated on the surface including a survey of significant alterations from biological origin. The approach carried out combined molecular biology methods and analytical procedures. The composition of the dust samples is very heterogeneous, comprising mineral particles resulting from the deterioration of the building materials, fragments of decorative elements particularly gold leaf from the gilded wood, products from air pollution (soot), as well as biological fragments of insects, arachnids and bird droppings, in addition to bacteria and fungal spores.

Paranhos constitutes one of the main water galleries excavated in the granite substratum of Porto City (Portugal) to gather the groundwater for public use during the past six centuries. The interest of this water gallery is double: a) Cultural Heritage and scientific value, b) Underground geoturism. A multidisciplinary research to study the microclimatology, geochemistry, mineralogy and geomicrobiology of the Paranhos catchwork galleries is currently in progress. The characterization of the main environmental parameters (air-rock temperature, relative humidity, CO2, 222Rn, etc.) in the internal atmosphere would allow the establishment of: a) Fluid-rock interactions and development of a physical-chemical model of air-water-rock, as a base to define their relations with unusual mineral formations and microbial communities b) Microclimatic parameters and determination of effective radioactive dose for visitors based on 222Rn studies, as potential use as underground geotourism site under safe conditions.

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.

The walls and ceiling of Altamira Cave, northern Spain, are coated with different coloured spots (yellow, white and grey). Electron microscopy revealed that the grey spots are composed of bacteria and bioinduced CaCO 3 crystals. The morphology of the spots revealed a dense network of microorganisms organized in well-defined radial and dendritic divergent branches from the central area towards the exterior of the spot, which is coated with overlying spheroidal elements of CaCO 3 and CaCO 3 nest-like aggregates. Molecular analysis indicated that the grey spots were mainly formed by an unrecognized species of the genus Actinobacteria. CO 2 efflux measurements in rocks heavily covered by grey spots confirmed that bacteria-forming spots promoted uptake of the gas, which is abundant in the cave. The bacteria can use the captured CO 2 to dissolve the rock and subsequently generate crystals of CaCO 3 in periods of lower humidity and/or CO 2. A tentative model for the formation of these grey spots, supported by scanning electron microscopy and transmission electron microscopy data, is proposed. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.