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The migration of geogenic gases in continental areas with geothermal activity and active faults is an important process releasing greenhouse gases (GHG) to the lower troposphere. In this respect, caves in hypogenic environments are natural laboratories to study the compositional evolution of deep-endogenous fluids through the Critical Zone. Vapour Cave (Alhama, Murcia, Spain) is a hypogenic cave formed by the upwelling of hydrothermal CO2-rich fluids. Anomalous concentrations of N2O and NO2 were registered in the cave's subterranean atmosphere, averaging ten and five times the typical atmospheric backgrounds, respectively. We characterised the thermal conditions, gaseous compositions, sediments, and microbial communities at different depths in the cave. We did so to understand the relation between N-cycling microbial groups and the production and transformation of nitrogenous gases, as well as their coupled evolution with CO2 and CH4 during their migration through the Critical Zone to the lower troposphere. Our results showed an evident vertical stratification of selected microbial groups (Archaea and Bacteria) depending on the environmental parameters, including O2, temperature, and GHG concentration. Both the N2O isotope ratios and the predicted ecological functions of bacterial and archaeal communities suggest that N2O and NO2 emissions mainly depend on the nitrification by ammonia-oxidising microorganisms. Denitrification and abiotic reactions of the reactive intermediates NH2OH, NO, and NO2− are also plausible according to the results of the phylogenetic analyses of the microbial communities. Nitrite-dependent anaerobic methane oxidation by denitrifying methanotrophs of the NC10 phylum was also identified as a post-genetic process during migration of this gas to the surface. To the best of our knowledge, our report provides, for the first time, evidence of a niche densely populated by Micrarchaeia, which represents more than 50% of the total archaeal abundance.

En el singular yacimiento de El Sidrón se han producido una impactante serie de acontecimientos relacionados con las actividades y comportamientos de la especie neandertal, integradas en unos procesos del medio físico peculiares, sazonadas con la proximidad de la mejor materia prima silícea asturiana, y con un peculiar encadenamiento de situaciones expeditivas y rápidas. Todo ello integrado en una investigación interdisciplinar., At the unique site of El Sidrón there have been an impressive series of events related to the activities and behaviors of the Neandertal species, integrated into peculiar environmental processes, seasoned with the proximity of the best Asturian siliceous raw material, and with a peculiar chain of expeditious and fast situations. All this integrated into an interdisciplinary investigation.

The Cross of the Inquisition, sculpted in 1903 and raised on a column with a fluted shaft and ornamented with vegetable garlands, is located in a corner of the Plateresque façade of the Seville City Hall. The Cross was vandalized in September 2019 and the restoration concluded in September 2021. A geological and microbiological study was carried out in a few small fragments. The data are consistent with the exposure of the Cross of the Inquisition to an urban environment for more than 100 years. During that time, a lichen community colonized the Cross and the nearby City Hall façades. The lichens, bryophytes and fungi colonizing the limestone surface composed an urban community, regenerated from the remains of the original communities, after superficial cleaning of the limestone between 2008 and 2010. This biological activity was detrimental to the integrity of the limestone, as showed by the pitting and channels, which evidence the lytic activity of organisms on the stone surface. Stone consolidation was achieved with Estel 1000. Preventol RI80, a biocide able to penetrate the porous limestone and active against bacteria, fungi, lichens, and bryophytes, was applied in the restoration.

The sandstones which constitute the host rock for the prehistoric artwork in the Rock Groups of Tajo de las Figuras and Peñas de Cabrera (southern Spain) show a serious degree of alteration, due both to natural processes and those related to anthropogenic and animal activity. A detailed study was carried out on the petrological and compositional characteristics of the sandstones (fresh and altered rock) in both rock groups, and on the geological and climatological characteristics of the area in which they are located. The sandstones have very similar petrological and compositional characteristics in both areas. This likeness causes the nature of the natural weathering processes to be similar in the rock areas studied. These processes can be divided in terms of the predominant mechanisms of alteration into three inter-related categories: mechanical weathering, chemical weathering, and bio-induced alteration processes. However, the different climatic conditions of the areas in which the two rock areas are located directly influences the intensity of these processes. The precipitation and the range of temperature variation with heavy winter frosts in the area of El Tajo de las Figuras are significantly higher than in the area of Peñas de Cabrera; this translates into a higher rate of weathering at El Tajo de las Figuras. Regarding the anthropogenic action, two types of influence on the deterioration can be distinguished: a direct one, which consists of scouring and wetting of the walls in order to increase the chromatic contrast; and an indirect one, which is the extraction of blocks of sandstone in the upper part of rock shelters, which in turn encourages the development of the chemical weathering processes.

Understanding the dynamics and spatial distribution of gases in the subterranean atmospheres is essential to increase the reliability of carbon balances in karst ecosystems or the paleoclimate reconstructions based on cave deposits. This scientific information is also very valuable for cave managers to ensure the safety of visitors and the conservation of the subterranean heritage. Through a comprehensive monitoring of the main air parameters in a shallow temperate cave, we decipher the physical drivers and mechanisms involved in the CO2 and radon exchange between the cave and the outer atmosphere, and how this process is triggered by the changes of local weather. Our results reveal that the biphasic infiltration (water plus air) in the network of penetrative structures from the overlying soil and host rock exercise remarkable control over the cave environment, delaying the thermal response of the cave air to the outer climate-driven changes and also the gaseous transfer between the cave atmosphere and the exterior. The cave location concerning the karstified outcrop determines that this subterranean site acts as a gas emitter during summer, which is contrary to what happens in many other caves. Prominent gas entrapment at a micro-local level is also registered in some upper galleries.

The Santo Domingo Diocesan School (Orihuela, SE Spain) is a singular case study that relates air quality monitoring and stone conservation. The monument suffers severe damage due to salt crystallization by rising damp, which is related to the indoor environment dynamics, high groundwater salt content, and microstructure, the building’s porous stone (biocalcarenite). Results revealed that 222Rn concentration in indoor air is low due to the building’s high ventilation rate, despite the medium-low geogenic radon potential in the area. Wavelets analysis showed that ventilation is caused by outdoor and indoor temperature variations and directly affects the 222Rn and CO2 dynamics inside the church. CO2, as well as relative humidity (RH), presented periodicities with intermediate frequencies (5–8 days) related to visits. These RH and temperature (T) variations intensified the salt damage by increasing the frequency of dissolution-crystallization cycles. The mineralogical characterization and geochemical calculations concluded that chlorides (halite and sylvite), sulfates (thenardite, epsomite, hexahydrite and aphthitalite) and nitrates (niter) present from dissolution forms to whiskers and hopper-type morphologies. This indicates high saturation values and, therefore, higher crystallization pressure values within the porous media of the biocalcarenite. On the contrary, the near-equilibrium crystal shape and incongruent precipitation reaction for humberstonite suggest a lower alteration for this salt on the building stone.

Arenaza Cave is located in Vizcaya (N Spain) and contains important Palaeolithic rock art representations. This cave belongs to an active karstic system developed on Lower Cretaceous limestones, mainly consisting of micrites and biomicrites with abundant pyrite moulds. The paintings are made directly on the host rock or on thin stalagmitic calcite crusts. Cretaceous limestones in this area contain important iron ore deposits, which have been mined by subsurface and surface-mining methods since the beginning of the 20th century. Mining activities have induced significant changes in the karstic drainage pattern and in the endo and exokarstic morphologies of the Arenaza karstic system, directly affecting the state of conservation of the prehistoric paintings. Thus, in addition to natural process of deterioration, the enlargement of the limestone fissure system as a result of blasting-induced vibrations seems to be the responsible for changes in the rates of water-rock interactions and of the formation of botryoidal gypsum concretions on the rock surface. The final result is the activation and acceleration of detachment processes and the increase of irreversible deterioration processes in the cave.

Arenaza Cave is located in Vizcaya (N Spain) and contains important Palaeolithic rock art representations. This cave belongs to an active karstic system developed on Lower Cretaceous limestones, mainly consisting of micrites and biomicrites with abundant pyrite moulds. The paintings are made directly on the host rock or on thin stalagmitic calcite crusts. Cretaceous limestones in this area contain important iron ore deposits, which have been mined by subsurface and surface-mining methods since the beginning of the 20th century. Mining activities have induced significant changes in the karstic drainage pattern and in the endo and exokarstic morphologies of the Arenaza karstic system, directly affecting the state of conservation of the prehistoric paintings. Thus, in addition to natural process of deterioration, the enlargement of the limestone fissure system as a result of blasting-induced vibrations seems to be the responsible for changes in the rates of water-rock interactions and of the formation of botryoidal gypsum concretions on the rock surface. The final result is the activation and acceleration of detachment processes and the increase of irreversible deterioration processes in the cave.

Understanding the dynamics and spatial distribution of gases in the subterranean atmospheres is essential to increase the reliability of carbon balances in karst ecosystems or the paleoclimate reconstructions based on cave deposits. This scientific information is also very valuable for cave managers to ensure the safety of visitors and the conservation of the subterranean heritage. Through a comprehensive monitoring of the main air parameters in a shallow temperate cave, we decipher the physical drivers and mechanisms involved in the CO2 and radon exchange between the cave and the outer atmosphere, and how this process is triggered by the changes of local weather. Our results reveal that the biphasic infiltration (water plus air) in the network of penetrative structures from the overlying soil and host rock exercise remarkable control over the cave environment, delaying the thermal response of the cave air to the outer climate-driven changes and also the gaseous transfer between the cave atmosphere and the exterior. The cave location concerning the karstified outcrop determines that this subterranean site acts as a gas emitter during summer, which is contrary to what happens in many other caves. Prominent gas entrapment at a micro-local level is also registered in some upper galleries.

The Cross of the Inquisition, sculpted in 1903 and raised on a column with a fluted shaft and ornamented with vegetable garlands, is located in a corner of the Plateresque façade of the Seville City Hall. The Cross was vandalized in September 2019 and the restoration concluded in September 2021. A geological and microbiological study was carried out in a few small fragments. The data are consistent with the exposure of the Cross of the Inquisition to an urban environment for more than 100 years. During that time, a lichen community colonized the Cross and the nearby City Hall façades. The lichens, bryophytes and fungi colonizing the limestone surface composed an urban community, regenerated from the remains of the original communities, after superficial cleaning of the limestone between 2008 and 2010. This biological activity was detrimental to the integrity of the limestone, as showed by the pitting and channels, which evidence the lytic activity of organisms on the stone surface. Stone consolidation was achieved with Estel 1000. Preventol RI80, a biocide able to penetrate the porous limestone and active against bacteria, fungi, lichens, and bryophytes, was applied in the restoration.

The sandstones which constitute the host rock for the prehistoric artwork in the Rock Groups of Tajo de las Figuras and Peñas de Cabrera (southern Spain) show a serious degree of alteration, due both to natural processes and those related to anthropogenic and animal activity. A detailed study was carried out on the petrological and compositional characteristics of the sandstones (fresh and altered rock) in both rock groups, and on the geological and climatological characteristics of the area in which they are located. The sandstones have very similar petrological and compositional characteristics in both areas. This likeness causes the nature of the natural weathering processes to be similar in the rock areas studied. These processes can be divided in terms of the predominant mecha nisms of alteration into three inter-related categories: mechanical weathering, chemical weathering, and bio-induced alteration processes. However, the different climatic conditions of the areas in which the two rock areas are located directly influences the intensity of these processes. The precipitation and the range of temperature variation with heavy winter frosts in the area of El Tajo de las Figuras are significantly higher than in the area of Peñas de Cabrera; this translates into a higher rate of weathering at El Tajo de las Figuras. Regarding the anthropogenic action, two types of influence on the deterioration can be distinguished: a direct one, which consists of scouring and wetting of the walls in order to increase the chromatic contrast; and an indirect one, which is the extraction of blocks of sandstone in the upper part of rock shelters, which in turn encourages the development of the chemical weathering processes.

At the unique site of El Sidrón there have been an impressive series of events related to the activities and behaviors of the Neandertal species, integrated into peculiar environmental processes, seasoned with the proximity of the best Asturian siliceous raw material, and with a peculiar chain of expeditious and fast situations. All this integrated into an interdisciplinary investigation, En el singular yacimiento de El Sidrón se han producido una impactante serie de acontecimientos relacionados con las actividades y comportamientos de la especie neandertal, integradas en unos procesos del medio físico peculiares, sazonadas con la proximidad de la mejor materia prima silícea asturiana, y con un peculiar encadenamiento de situaciones expeditivas y rápidas. Todo ello integrado en una investigación interdisciplinar

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.

The Santo Domingo Diocesan School (Orihuela, SE Spain) is a singular case study that relates air quality monitoring and stone conservation. The monument suffers severe damage due to salt crystallization by rising damp, which is related to the indoor environment dynamics, high groundwater salt content, and microstructure, the building’s porous stone (biocalcarenite). Results revealed that 222Rn concentration in indoor air is low due to the building’s high ventilation rate, despite the medium-low geogenic radon potential in the area. Wavelets analysis showed that ventilation is caused by outdoor and indoor temperature variations and directly affects the 222Rn and CO2 dynamics inside the church. CO2, as well as relative humidity (RH), presented periodicities with intermediate frequencies (5–8 days) related to visits. These RH and temperature (T) variations intensified the salt damage by increasing the frequency of dissolution-crystallization cycles. The mineralogical characterization and geochemical calculations concluded that chlorides (halite and sylvite), sulfates (thenardite, epsomite, hexahydrite and aphthitalite) and nitrates (niter) present from dissolution forms to whiskers and hopper-type morphologies. This indicates high saturation values and, therefore, higher crystallization pressure values within the porous media of the biocalcarenite. On the contrary, the near-equilibrium crystal shape and incongruent precipitation reaction for humberstonite suggest a lower alteration for this salt on the building stone.

El Sidrón Cave is an archaeological and anthropological reference site of the Neanderthal world. It shows singular activity related to cannibalisation, and all existing processes are relevant to explain the specific behaviour of the concerned individuals. This paper presents geoarchaeological data, primarily based on mineralogical and petrographic techniques, from an investigation of the nature of the encrustations or hard coatings that affect a large part of the Neanderthal bone remains and their relationship with the depositional and post-depositional processes at the archaeological site. Crusts and patina were found to be numerous and diverse, mainly composed of calcite and siliciclastic grains, with different proportions and textures. The analysis indicated different origins and scenarios from their initial post-mortem accumulation to the final deposit recovered during the archaeological work. The presence of micromorphological features, such as clotted-peloidal micrite, needle-fibre calcite (NFC) aggregates, clay coatings, iron–manganese impregnation, and/or adhered aeolian dust may indicate that a significant proportion of the remains were affected by subaerial conditions in a relatively short period of time in a shelter, cave entrance, or shallower level of the karstic system, prior to their accumulation in the Ossuary Gallery.

The purpose of this paper is to model numerically the dynamics of CO2 and 222Rn in cave atmospheres, particularly in the noteworthy Cave of Altamira (Spain). We aim to get a better understanding of the nature of these dynamics and their couplings with climatic controls, more specifically the soil water content, which role in the said dynamics poses some questions. For the first time, we apply the global modeling technique in the field of cave microclimate and atmospheric composition. The global modeling technique is a methodology based on the theory of nonlinear systems and designed to extract mathematical models directly from observational time series. We were able to extract four global models from our data. These models represent a step forward from the existent conceptual ones. They also show that CO2 and 222Rn dynamics can be approximated by low-dimensional, deterministic systems, which can be chaotic or, at least, close to chaos; this has decisive methodological consequences for future research. Moreover, the global modeling technique was used for the first time in a non-autonomous formulation; this enabled the possibility of studying the influence of the external forcing (soil water content) on the gas concentration in different scenarios.

A medida que se investiga y aprende sobre el funcionamiento de los ambientes subterráneos, lo que se conoce coloquialmente como las cuevas, se adquiere una mayor conciencia de la importancia de estos ecosistemas en el funcionamiento global del planeta: lo que sucede en superficie tiene influencia directa en el desarrollo y las condiciones de la vida en el subsuelo, así como también hay una retroalimentación entre los cambios biogeoquímicos del subsuelo, tanto estacionales como a largo plazo (ligados al cambio climático), y las condiciones de vida en la superficie. Es cada vez más numerosa la literatura científica que aborda diferentes estudios sobre la Zona Crítica de la Tierra, entendida esta como la capa más superficial de la corteza terrestre donde se producen e interactúan todos los procesos físicos, químicos y biológicos fundamentales para el mantenimiento de la vida (Moravec & Chorover, 2020). Los ecosistemas subterráneos forman una parte esencial de la Zona Crítica, en torno al 20% de la superficie continental libre de hielo se caracteriza por la presencia de rocas carbonáticas karstificables y que, por tanto, potencialmente pueden albergar cavidades próximas a la superficie. Son hábitats especiales para numerosas especies y contienen biomasa microbiana abundante y activa que vive tanto en el agua subterránea como en el sistema poroso de sedimentos y rocas. El hecho de que sean accesibles los convierte en laboratorios naturales de un enorme valor para numerosas disciplinas científicas.

El pasado 10 de septiembre como consecuencia de un acto vandálico se ocasionan daños de gravedad en la Cruz de la Inquisición, ubicada en la plaza de San Francisco, en el ángulo formado entre el arquillo y la Sala Capitular Baja del Ayuntamiento de Sevilla. Desde la dirección del Real Alcázar se encarga la inspección de la pieza, la valoración de su estado de conservación y de los daños ocasionados en este acto. Los resultados de la inspección concluyeron el deficiente estado de conservación de la obra y aconsejaban realizar una intervención integral de conservación- restauración que le devuelva la estabilidad material y los valores estéticos perdidos. Como consecuencia de los daños mecánicos de tipo antrópico, ocasionados en la agresión a la cruz, y de las patologías originadas por agentes de tipo medioambiental o intrínseco a la naturaleza material y constructiva del elemento, el estado de conservación es muy deficiente.

El Sidrón Cave is an archaeological and anthropological reference site of the Neanderthal world. It shows singular activity related to cannibalisation, and all existing processes are relevant to explain the specific behaviour of the concerned individuals. This paper presents geoarchaeological data, primarily based on mineralogical and petrographic techniques, from an investigation of the nature of the encrustations or hard coatings that affect a large part of the Neanderthal bone remains and their relationship with the depositional and post-depositional processes at the archaeological site. Crusts and patina were found to be numerous and diverse, mainly composed of calcite and siliciclastic grains, with different proportions and textures. The analysis indicated different origins and scenarios from their initial post-mortem accumulation to the final deposit recovered during the archaeological work. The presence of micromorphological features, such as clotted-peloidal micrite, needle-fibre calcite (NFC) aggregates, clay coatings, iron–manganese impregnation, and/or adhered aeolian dust may indicate that a significant proportion of the remains were affected by subaerial conditions in a relatively short period of time in a shelter, cave entrance, or shallower level of the karstic system, prior to their accumulation in the Ossuary Gallery.

The thermal spring of Fetida Cave, a still active sulfuric acid cave opening at sea level and located in Santa Cesarea Terme, southeastern Salento (Apulia region, Southern Italy) hosts abundant floating white filaments. The white filaments were mainly composed of sulfur crystals surrounded by microbial mass of the phyla Epsilonbacteraeota, Proteobacteria, Bacteroidetes, and Patescibacteria. The most abundant genus in the white filaments collected from the waters in the innermost part of the cave dominated by sulfidic exhalations was Arcobacter. This abundance can be related to the higher concentration of sulfide dissolved in water, and low oxygen and pH values. Conversely, lower Arcobacter abundances were obtained in the filaments collected in the entrance and middle part of the cave, where sulfidic water mixes with seawater, as the cave is subjected to tides and the mixing of fresh (continental) with marine water. The geochemical analysis of water and atmospheric gases confirmed these environmental constraints. In fact, the highest concentrations of H2S in the air and water were recorded closest to the spring upwelling in the innermost part of the cave, and the lowest ones near the cave entrance. The metabolic versatility of Arcobacter might provide a competitive advantage in the colonization of water bodies characterized by high sulfide, low oxygen, and dynamic fluid movement.

[ES] El inicio del poblamiento humano en la isla de Bioko (antigua Fernando Poo) (Guinea Ecuatorial) es un tema mal conocido. Investigaciones previas establecen una secuencia de ocupación exclusivamente Holocena a pesar de que Bioko ha estado conectada con el continente durante al menos el último periodo glacial. Con objeto de localizar evidencias de ocupación pleistocena se localizaron 44 afloramientos, distinguiéndose sedimentos volcánicos, materiales eluviales, volcano-sedimentarios y aluviales. Entre estos cabe destacar el hallazgo de una larga serie de sedimentos lacustres correspondientes a un paleolago ubicado en un cráter. Apesar de lo exhaustivo de las prospecciones no se halló ninguna evidencia de presencia humana atribuible a una cronología pleistocena. Nuestros resultados confirman una ocupación muy tardía de Bioko posterior a los 8000 años BP. La ausencia de ocupaciones previas podría obedecer a condiciones ecológicas hostiles (pluviosidad, parasitismo), aunque es posible que las ocupaciones pleistocenas estuvieran restringidas a las zonas costeras y que estas se encuentren hoy sumergidas., [EN] The beginning of human settlement on the island of Bioko (formerly Fernando Poo) (Equatorial Guinea) is a poorly known issue. Previous research establishes an exclusively Holocene occupation sequence despite the fact that Bioko has been connected to the mainland, at least, during the last ice age. In order to locate evidence of Pleistocene occupation, 44 points / outcrops were located, distinguishing volcanic sediments and eluvial and alluvial volcano-sedimentary materials. These include the discovery of a long series of lake sediments corresponding to a paleolake located in a crater. Despite the exhaustiveness of the surveys, no evidence of human presence attributable to a Pleistocene chronology was found. Our results confirm a very late occupation of Bioko after 8000 years BP. The absence of previous occupations could be due to hostile ecological conditions (rainfall, parasitism), although it is possible that Pleistocene occupations were restricted to coastal areas and that these are now submerged.

The purpose of this paper is to model numerically the dynamics of CO and Rn in cave atmospheres, particularly in the noteworthy Cave of Altamira (Spain). We aim to get a better understanding of the nature of these dynamics and their couplings with climatic controls, more specifically the soil water content, which role in the said dynamics poses some questions. For the first time, we apply the global modeling technique in the field of cave microclimate and atmospheric composition. The global modeling technique is a methodology based on the theory of nonlinear systems and designed to extract mathematical models directly from observational time series. We were able to extract four global models from our data. These models represent a step forward from the existent conceptual ones. They also show that CO and Rn dynamics can be approximated by low-dimensional, deterministic systems, which can be chaotic or, at least, close to chaos; this has decisive methodological consequences for future research. Moreover, the global modeling technique was used for the first time in a non-autonomous formulation; this enabled the possibility of studying the influence of the external forcing (soil water content) on the gas concentration in different scenarios.

Of the several critical challenges present in environmental microbiology today, one is the assessment of the contribution of microorganisms in the carbon cycle in the Earth-climate system. Karstic subterranean ecosystems have been overlooked until recently. Covering up to 25% of the land surface and acting as a rapid CH4 sink and alternately as a CO2 source or sink, karstic subterranean ecosystems play a decisive role in the carbon cycle in terms of their contribution to the global balance of greenhouse gases. Recent data indicate that microbiota must play a significant ecological role in the biogeochemical processes that control the composition of the subterranean atmosphere, as well as in the availability of nutrients for the ecosystem. Nevertheless, there are still essential gaps in our knowledge concerning the budgets of greenhouse gases at the ecosystem scale and the possible feedback mechanisms between environmental-microclimatic conditions and the rates and type of activity of microbial communities in subterranean ecosystems. Another challenge is searching for bioactive compounds (antibiotics) used for treating human diseases. At present, there is a global health emergency and a strong need for novel biomolecules. In recent decades, great research efforts have been made to extract antibiotics from marine organisms. More recently, caves have been receiving considerable attention in search of novel antibiotics. Cave methanotrophic and heterotrophic bacteria are producers of bioactive compounds and may be potential sources of metabolites with antibacterial, antifungal or anticancer activities of interest in pharmacological and medical research, as well as enzymes with a further biotechnological use. Here we also show that bacteria isolated from mines, a still unexplored niche for scientists in search of novel compounds, can be a source of novel secondary metabolites.

Understanding the fluctuations in cave air concentrations and their climatic control is substantial not only to preserve the quality of indoor atmospheres but also to avoid the risk related to the presence of hazardous substances. In this study, we investigated the most influential factors affecting 222Rn and CO2 concentrations, the nature of their dynamics, and their coupling with climatic variations. For this purpose, we combined a set of mathematical methods that included a statistical and wavelet analysis of a 6-year time series in Rull Cave (Spain). Generally, the 222Rn and CO2 dynamic in cave air showed similar patterns. However, the obtained results show that these gases have a different frequency response. Thus, the annual component of 222Rn and CO2 is controlled by the relationship between external and internal temperatures. At low frequencies, both gases are affected by the same variables when the cave atmosphere reaches a minimum concentration. However, when the cave atmosphere is isolated from the outdoors, 222Rn and CO2 behave differently and disturbance caused by the visitors is evidenced in terms of the CO2 concentration; the latter observation was confirmed by the wavelet analysis at high frequencies. In contrast, the 222Rn concentration shows important variations following rainfall, which was weakly identified in the CO2 concentration.

The sites of La Viña and Llonin have an important archaeological sequence corresponding to Marine Isotope Stage 3: Mousterian, Aurignacian and Gravettian periods. La Viña is a complex rock shelter with continuous occupations, being some (basically the Mousterian and the Aurignacian in contact levels) altered by post-depositional processes as a consequence of the irregular bedrock morphology and the type of processes involved. The cave of Llonin mainly consists of occasional human/carnivores occupations during the Mousterian and the Gravettian. The current multidisciplinary research has allowed us to obtain and match several preliminary data: site formation processes, fauna and stable isotopes, vegetation, radiocarbon dating, shell ornaments, lithic raw materials and technology, offering an interesting field of study of two relatively distant ecological niches: open river valley (La Viña) and mountainous (Llonin). During the Mousterian, the faunal composition of La Viña is scarce but dominated by red deer and followed by chamois, while large mammals are absent. At the Aurignacian, red deer and chamois are also represented within a larger assemblage, together with a low representation of other taxa such as horse, bovines, Spanish ibex and roe deer. Conversely, in Llonin chamois and Spanish ibex dominate during the Mousterian, followed by red deer. Carnivores are few in La Viña they are represented by bear, fox and wolf; while in Llonin they are larger and other species are included, mainly leopard and hyena with a main role in the formation of the faunal assemblages and alternating their occupation of the cave with the Neandertals. On the other hand, the ungulates from La Viña are anthropogenically modified not only during the Mousterian but also the Aurignacian and Gravettian in contrast to Llonin, were these modifications are lower than those generated by the carnivores. Firewood and micromammals analysis show an open landscape, dominated by heliophilous, pioneering

The Necropolis of Carmona, which has more than 600 tombs carved in calcarenites, is among the most important Roman burial sites preserved in southern Spain. The tombs in the Necropolis show severe alteration and multiple weathering processes after being excavated at the end of the nineteenth century without a preventive conservation plan. The archaeological site shows strong anthropic modifications related to different excavation stages and in relation to the construction of facilities for the visiting public. In particular, the exposure of the buried tombs to meteoric conditions and anthropic modification of natural drainage have led to an important acceleration of the deterioration of the tombs. The conservation status of the Necropolis was defined through a comprehensive geo‐environmental study that combined field observations and laboratory data, modelling and digital mapping and environmental monitoring. Results allow a methodology to be developed providing guidelines to minimize potential risks when excavating new tombs (now buried) in the future. Moreover, the most suitable prospective areas can be defined inside the Necropolis in terms of the environmental, geological and geomorphological conditions which will enhance the preservation of newly exhumed tombs. Geo‐environmental preventive conservation methods that we propose can be entirely applied to other large archaeological sites completely exposed to open‐air atmospheric conditions.

The Necropolis of Carmona, which has more than 600 tombs carved in calcarenites, is among the most important Roman burial sites preserved in southern Spain. The tombs in the Necropolis show severe alteration and multiple weathering processes after being excavated at the end of the nineteenth century without a preventive conservation plan. The archaeological site shows strong anthropic modifications related to different excavation stages and in relation to the construction of facilities for the visiting public. In particular, the exposure of the buried tombs to meteoric conditions and anthropic modification of natural drainage have led to an important acceleration of the deterioration of the tombs. The conservation status of the Necropolis was defined through a comprehensive geo-environmental study that combined field observations and laboratory data, modelling and digital mapping and environmental monitoring. Results allow a methodology to be developed providing guidelines to minimize potential risks when excavating new tombs (now buried) in the future. Moreover, the most suitable prospective areas can be defined inside the Necropolis in terms of the environmental, geological and geomorphological conditions which will enhance the preservation of newly exhumed tombs. Geo-environmental preventive conservation methods that we propose can be entirely applied to other large archaeological sites completely exposed to open-air atmospheric conditions.

The sites of La Viña and Llonin have an important archaeological sequence corresponding to Marine Isotope Stage 3: Mousterian, Aurignacian and Gravettian periods. La Viña is a complex rock shelter with continuous occupations, being some (basically the Mousterian and the Aurignacian in contact levels) altered by post-depositional processes as a consequence of the irregular bedrock morphology and the type of processes involved. The cave of Llonin mainly consists of occasional human/carnivores occupations during the Mousterian and the Gravettian. The current multidisciplinary research has allowed us to obtain and match several preliminary data: site formation processes, fauna and stable isotopes, vegetation, radiocarbon dating, shell ornaments, lithic raw materials and technology, offering an interesting field of study of two relatively distant ecological niches: open river valley (La Viña) and mountainous (Llonin). During the Mousterian, the faunal composition of La Viña is scarce but dominated by red deer and followed by chamois, while large mammals are absent. At the Aurignacian, red deer and chamois are also represented within a larger assemblage, together with a low representation of other taxa such as horse, bovines, Spanish ibex and roe deer. Conversely, in Llonin chamois and Spanish ibex dominate during the Mousterian, followed by red deer. Carnivores are few in La Viña they are represented by bear, fox and wolf; while in Llonin they are larger and other species are included, mainly leopard and hyena with a main role in the formation of the faunal assemblages and alternating their occupation of the cave with the Neandertals. On the other hand, the ungulates from La Viña are anthropogenically modified not only during the Mousterian but also the Aurignacian and Gravettian in contrast to Llonin, were these modifications are lower than those generated by the carnivores. Firewood and micromammals analysis show an open landscape, dominated by heliophilous, pioneering

Understanding the fluctuations in cave air concentrations and their climatic control is substantial not only to preserve the quality of indoor atmospheres but also to avoid the risk related to the presence of hazardous substances. In this study, we investigated the most influential factors affecting 222Rn and CO2 concentrations, the nature of their dynamics, and their coupling with climatic variations. For this purpose, we combined a set of mathematical methods that included a statistical and wavelet analysis of a 6-year time series in Rull Cave (Spain). Generally, the 222Rn and CO2 dynamic in cave air showed similar patterns. However, the obtained results show that these gases have a different frequency response. Thus, the annual component of 222Rn and CO2 is controlled by the relationship between external and internal temperatures. At low frequencies, both gases are affected by the same variables when the cave atmosphere reaches a minimum concentration. However, when the cave atmosphere is isolated from the outdoors, 222Rn and CO2 behave differently and disturbance caused by the visitors is evidenced in terms of the CO2 concentration; the latter observation was confirmed by the wavelet analysis at high frequencies. In contrast, the 222Rn concentration shows important variations following rainfall, which was weakly identified in the CO2 concentration.

In the last few years, a sharp increase in the number of descriptions of new species of West African cone snails, particularly from the Cabo Verde Archipelago, has taken place. In previous studies, we used mitogenome sequences for reconstructing robust phylogenies, which comprised in total 120 individuals representing the majority of species (69.7%) described from this biogeographical region (except Angolan endemics) and grouped into seven genera within the family Conidae. Here, we add another 12 individuals representing endemic species that were missing in the previous studies. We use the phylogenies to identify monophyletic groups and a genetic divergence threshold (0.2% uncorrected p distance) to determine the number of valid species. As a result, the number of valid West African cone species could be drastically reduced to at least 40%, indicating that some recent poor-quality descriptions loosely based on phenotypic characters prone to convergence such as the shape and color patterns of the shell have contributed substantially to taxonomic inflation. Several previously accepted species with a reduced geographical distribution now become phenotypic forms of the remaining valid species, which increase their distribution ranges. In contrast, several cryptic species are now uncovered and described. For instance, Africonus insulae sp. nov. and Kalloconus canariensis sp. nov. are hereby introduced as new species. A detailed systematic account with illustrations and relevant information is presented. Lectotypes are designated for Conus trochulus and Conus irregularis, and neotypes for Conus crotchii and Conus diminutus. According to our results, it is strongly recommended that any future introduction of new taxa names for cone snails from West Africa should be supported by molecular and/or anatomical rather than exclusively shell morphological data. The taxonomic decisions here taken have direct implications for conservation and will eventually require re-evaluation o

Fluid migration along faults can be highly complex and spatially variable, with channelled flow along karstified structures of the vadose zone. One such example is Vapor cave, near the urban area of Alhama de Murcia, situated along a tectonically active, NE-SW trending master fault as results of the convergence between Africa and the microplate of Iberia. Vapor cave represents an outstanding gases-blowout site from the upper vadose zone, developed in a favourably fissured carbonate-cemented conglomerate host rock under hypogene speleogenesis by the upwelling of hydrothermal (>33°C, and 100% relative humidity) and CO2-rich air, in or from the zone of fluid-geodynamic influence.In this study, we investigate the gaseous composition and, specifically, the geochemical fingerprint of deep-origin greenhouse gases (CO2, CH4) of both cave and soil air at Vapor cave. Detailed surveys were conducted to monitor the deep-origin gases exhaled by the cave, by using high precision field-deployable CRDS and FTIR spectrometers to in situ and real time measure the concentration and 13C of both carbon-GHGs. Inert gases like radon were also measured in parallel by a pulse-counting ionization chamber (alpha spectroscopy). The collected data provide new insights into the control exerted by active fault segments on deep-seated gas migration toward the surface.The C species of the deep-origin fluids are dominated by CO2 (concentration higher than 1% and 13C-CO2 ranging from 4.5 to 7.5) with the abundance of CH4 below the atmospheric background. It is estimated that the exhaled air represents between 1 to 3% of this pure¿theoretical CO2 added from the deep endogenous source feeding the cave atmosphere and linked to the fault activity. Anomalous radon concentrations recorded at this site also confirm the contribution of this geogenic gas in the cave atmosphere (222Rn ranges 40-60 kBq/m3 at -30 m depth) and its accumulation in the overlying soil (exceeding 10K kBq/m3).In contrast to the releas

The hydrothermal caves linked to active faulting have subterranean atmospheres with a distinctive gaseous composition containing deep endogenous gases, such as carbon dioxide, methane and nitrogen oxides (NOx). Ascending fluids through associated near-surface hydrothermal processes can mobilize endogenous gases into the Critical Zone and, ultimately, to the lower troposphere. Nitrogen oxides are polluting gases and can have adverse effects on human health, especially inhaled NO2. They also catalyse ozone (O3) production in the lower layers of the atmosphere and the greenhouse effect, when they react with volatile organic compounds. The largest source of NOx emissions is anthropogenic. The rest is produced naturally by microbial processes in soil and water, by lightning, volcanic activity, storms, etc. Production of N2O and NO2 is associated with soil and other active-geothermal ecosystems, far less is known about the sources and sinks of these gases within subterranean locations. Here, we report high N2O and NO2 concentrations detected along a hypogenic system associated with an active faulting (Vapour Cave, southern Spain), which enables direct gas exchange with the low-atmosphere. These anomalous concentrations of N2O and, NO2 are about ten and five times higher than the typical atmospheric background, respectively. Gaseous composition analyses of subterranean atmosphere were conducted by high precision field-deployable CRDS and FTIR spectrometers for measuring in situ the target tracer gases (NO2, N2O, CH4, CO2) and ¿13C of both carbon-GHGs. DNA extraction, sequencing and phylogenetic analyses were conducted to characterize the microbial community of cave sediments. The results showed that N2O and NO2 emission depends on the activity of nitrification by ammonia oxidizing microorganisms (such as members of the family Nitrosomonadaceae and phylum Thaumarchaeota) and/or as a result of incomplete denitrification by heterotrophic denitrifying bacteria (such as Bacillu

Karsts cover up to 25 % of the land surface and contain significant sedimentary deposits that become active cave-soils. Subterranean karst ecosystems play an active role in the global carbon cycle in terms of their contribution to the global GHG balance. They act alternately as a source or sink of CO2 and as a rapid sink of CH4. The most recent results indicate that microbiota must play a significant ecological role in the biogeochemical processes that control the subterranean atmosphere composition. Soils forming underneath the surface must host a large part of the subterranean microbiota. But to date, their behaviour concerning the production of gases and exchange with the ¿confined troposphere¿ has not been evaluated. Systematic direct estimates of CO2 and CH4 fluxes from cave-soils do not exist in literature. And they are needed before global generalizations can be made about the carbon budgets (emissions and sinks) of karstic ecosystems.Here we present pioneering research to evaluate the carbon fluxes from the cave soils directly exchanged with the cave atmosphere. This preliminary study is the first approach to systematically characterize the role of cave-soils in the production and transport of CO2 and CH4 in the subterranean environment. We carried out automatic in situ and real-time monitoring of CO2 and CH4 diffusive fluxes from a sedimentary alluvial soil in Pindal cave for one year (north Spain). We developed seasonal campaigns for CH4 and CO2 fluxes daily continuous monitoring by a LICOR closed chamber-based gas exchange system, in conjunction with a compatible Gasmet FTIR gas analyser. Moreover, autonomous equipment monitored the main micro-environmental parameters of the local subsurface-soil-atmosphere system. To interpret gas exchange processes and rates, and to understand the underlying mechanisms in soils, we also carried out seasonal ¿13C geochemical tracing by using Picarro cavity ring-down spectroscopy, through simultaneous cave atmosphere-soil

The presence of nestlings and other nest dwelling organisms in cavity nests alters the composition of gasses inside the cavity. Differential concentrations of gasses could be used by some parasites as a cue to localize their hosts. Here, we explored temporal variation in the concentration and isotopic signature of carbon dioxide (CO) and methane (CH) inside nest boxes of blue tits (Cyanistes caeruleus) during the nestling period (on days 3, 8, 13, 20, and 21 post-hatching) as well as several variables potentially affecting such variation. Finally, we checked whether differences in gas concentrations affect the abundance of different types of parasites affecting nestlings. Gas concentration and isotopic signature were significantly different between nest boxes and the forest during the nestling period. The CO concentration was higher inside nests than in the forest air, whereas CH concentration was lower. We expected to observe a positive correlation between the abundance of parasites actively seeking nests (i.e., blackflies, biting midges, and blowflies) and differences in gas concentration for those species that use these differences as a cue for host location. We observed that biting midge abundance was positively related to differences in CO between nest and forest air at day 20 of nestling age, indicating that this species can use these differences to locate hosts. We also found a positive relationship between blackfly abundance and differences in CH concentration. However, we hypothesize that the concentration of this gas inside nests may be related with bacterial activity; therefore, this relationship may be due to an effect of bacteria on blackflies and not to the effect of CH as an attraction cue for blackflies.

Of the several critical challenges present in environmental microbiology today, one is the assessment of the contribution of microorganisms in the carbon cycle in the Earth-climate system. Karstic subterranean ecosystems have been overlooked until recently. Covering up to 25% of the land surface and acting as a rapid CH4 sink and alternately as a CO2 source or sink, karstic subterranean ecosystems play a decisive role in the carbon cycle in terms of their contribution to the global balance of greenhouse gases. Recent data indicate that microbiota must play a significant ecological role in the biogeochemical processes that control the composition of the subterranean atmosphere, as well as in the availability of nutrients for the ecosystem. Nevertheless, there are still essential gaps in our knowledge concerning the budgets of greenhouse gases at the ecosystem scale and the possible feedback mechanisms between environmental-microclimatic conditions and the rates and type of activity of microbial communities in subterranean ecosystems. Another challenge is searching for bioactive compounds (antibiotics) used for treating human diseases. At present, there is a global health emergency and a strong need for novel biomolecules. In recent decades, great research efforts have been made to extract antibiotics from marine organisms. More recently, caves have been receiving considerable attention in search of novel antibiotics. Cave methanotrophic and heterotrophic bacteria are producers of bioactive compounds and may be potential sources of metabolites with antibacterial, antifungal or anticancer activities of interest in pharmacological and medical research, as well as enzymes with a further biotechnological use. Here we also show that bacteria isolated from mines, a still unexplored niche for scientists in search of novel compounds, can be a source of novel secondary metabolites