Caves as observatories for atmospheric thermal tides: an example from Ascunsă Cave, Romania

As part of a microclimate study at Ascunsă Cave, Romania, we used Gemini Tinytag Plus 2 data loggers to record cave air temperature variability. At one of the monitoring points we recognized the presence of semidiurnal cycles on the order of a few thousands of a degree Celsius that could be produced under the influence of the semidiurnal tidal components of the Sun (S2) or the Moon (M2). Using a Gemini Tinytag Plus 2 data logger with an external probe we measured core rock temperature and showed that it does not influence the cave air temperature on such short time scales. We thus rejected the possibility that Earth tides, mostly produced by the lunar tidal influence on the Earth’s crust, would have had a semidiurnal influence on cave air temperature. Moreover, time series analysis revealed a 12.00-hour periodicity in temperature data, specific for the S2, allowing us to assign these variations to the influence of the thermo-tidal action of the Sun. Using the Ideal Gas Law and assuming a constant volume and amount of air, we calculated that a theoretical change in atmospheric pressure of around 40 Pa was needed to produce the temperature changes we observed. This agrees with published values of atmospheric pressure changes induced by the semidiurnal solar component of the thermal tides (S2(t)). We thus can assign the observed temperature changes to semidiurnal atmospheric pressure changes (S2(p)) induced by the thermal excitation of the Sun. Our study signals the possibility that readily available data from cave monitoring studies around the world could be used in the study of atmospheric tides. Moreover, it appears that Ascunsă Cave acts as a natural meteorological filter on a short time scale, removing the direct thermal influences of the Sun (especially night and day differences) and preserving only the barometric information from the surface

Non-compaction cardiomyopathy – brief review

Left ventricular non-compaction cardiomyopathy is a genetic disorder characterized by the presence of two myocardial layers with numerous prominent trabeculations and deep inter-trabecular recesses that communicate with the ventricular cavity. The diagnosis is often challenging because excessive trabeculations may also be a normal finding in performance athletes and black people. Echocardiography is the gold standard for diagnosis of this condition, but other useful diagnostic techniques may include cardiac magnetic resonance imaging, computed tomography, and contrast ventriculography. Moreover, newer echocardiographic methods such as three-dimensional imaging and speckle tracking analysis promise to improve the diagnosis of left ventricular non-compaction cardiomyopathy. The purpose of this paper is to review the pathogenesis, diagnosis, and management of this disease

Farmed calcite δ13C at Ascunsă Cave, Romania, and its relation with CO2 outgassing and drip rate

When calcite precipitates in caves, its carbon stable isotope signature can be modified by the CO2 outgassing gradient between drip water and cave atmosphere. This effect is modulated by water residence time in the cave, from its emergence in the cave until the deposition of calcite. Moreover, CO2 solubility, calcite precipitation rate, and isotopic fractionation are controlled by temperature. Here, we present up to date results of an ongoing monitoring study at Ascunsă Cave (Romania), exploring the relationship between farmed calcite δ13C, drip rate, and CO2 outgassing. In addition to measuring CO2 concentration in cave air, we also measured the CO2 concentration in the headspace of a water-air equilibrator that collects drip water without exposing it to cave atmosphere, preventing outgassing. δ13C from calcite farmed at two neighboring stalagmites with different drip rates was also measured. Although caves have generally stable temperatures, we show here that temperature inside Ascunsă and Isverna caves has risen by more than 2°C over the course of a year, bearing important implications for stable isotopic fractionation equations and CO2 dynamics. Our results show that δ13C of farmed calcite has a strong relationship with drip rate at the slow dripping site, but no correlation at the faster dripping site. These two sites are also different when δ13C is compared to the outgassing gradient. At the slower drip site, δ13C and the outgassing gradient are directly correlated, whereas at the faster drip site their correlation is inverse. Our study brings new light onto speleothem δ13C behavior in general, and at Ascunsă Cave in particular, which is crucial for understanding the paleoclimate information captured by speleothems from this cave or elsewhere

Quaternary environmental evolution in the South Carpathians reconstructed from glaciokarst geomorphology and sedimentary archives

The Carpathian island-type glaciokarst has a great potential of preserving signals of past environments, archived in cave deposits like speleothems and clastic infills. We present here the geomorphology and structural control of several relict alpine caves and the surrounding glaciated marble karst in the Făgăraș Mountains. Four truncated and partially unroofed caves remained on the ridge-top of Mușeteica Mountain, above the glacial cirque, while a ponor cave that developed on the cirque bottom could be related to the Last Glacial Period. Structural measurements and cave morphology showed that the conduits formed at the intersection of foliation planes and tectonic fractures on the NE-SW and NW-SE directions. Cave development reflects three speleogenetic stages: 1) texture- and fabric-controlled dissolution and distension; 2) structurally-controlled breakdown; and 3) truncation, unroofing, and cave infilling with sediments. Slow diffuse dissolution was typical for the ridge-top caves, whereas M1 Cave developed by pressure flow

Geomorphological and structural patterns of the scarp‑related steep dry valleys in limestone ridges: A case study from South Carpathians, Romania

Scarp retreat is a common natural process which drives the evolution of landscape in monoclinal or horizontally bedded structures. The NW‑facing, retreating limestone slope of the Vânturarița‑Buila Massif, a mountain ridge in the South Carpathians, is incised by steep dry valleys (SDVs), parallel to each other and perpendicular to the ridge crest. We performed morphometric and structural analyses on these features in order to estimate the geomorphic control on the scarp retrogressive evolution and their relations to tectonics. Longitudinal profiles display most of their relevant morphometry. Average slope commonly ranges between 35° and 50°, often exceeding 60° on certain segments. Lengths reflect the variability of exposed caprock thickness, and changes in slope show the structural control of bedding on scarp morphology. Spatial distribution and development of the steep dry valleys, as well as the scarp retreat process, is controlled by tectonic lineaments. We performed a comparative orientation analysis on fractures of extensional origin, dextral strike‑slip faults, major faults, and steep dry valleys. Results show preferred orientations on the NW‑SE and NE‑SW. Variability in size and morphology of the amphitheater‑shaped scarp sectors depends on the exposed caprock thickness. Speleothems formed in crevice‑type caves and unearthed by scarp retreat were found along some of the steep dry valleys. This study shows that combined geomorphological and structural analysis of steep dry valleys from alpine limestone ridges can provide valuable information on the evolution and morphology of the retreating scarp they develop on.Le recul d'un escarpement est un processus naturel normal qui contrôle l'évolution du paysage des structures monoclinales ou tabulaires. Le versant calcaire, de regard N‑O, du Massif Vânturarița‑Buila, une chaîne de montagnes située dans les Carpates Méridionales, est fortement incisé par des vallées profondes et sèches, parallèles entre elles et perpendiculaires à la direction de la crête de la montagne. Nous avons effectué une analyse morphométrique et structurale de ces éléments afin d'estimer le contrôle géomorphologique sur l'évolution régressive de l'escarpement et ses relations avec la tectonique. L'analyse des profils longitudinaux permet de définir la plupart des paramètres morphométriques pertinents. La pente moyenne varie habituellement entre 35° et 50°, mais dépasse souvent 60°. Les longueurs reflètent la variabilité de l'épaisseur de la roche calcaire exposée et les changements des valeurs de pente expriment le contrôle structural de la stratification qui explique le caractère abrupt de la morphologie. La distribution spatiale et le développement des vallées sèches encaissées (type 'cheminée') et le processus de retrait de l'escarpement sont contrôlés par des linéaments tectoniques. Nous avons effectué une analyse comparative de l’orientation des fractures extensionnelles, des failles décrochantes dextres, des failles majeures et des vallées sèches escarpées. Les résultats montrent une orientation préférentielle le long de l’axe NO‑SE et NE‑SO. La variabilité de taille et de morphologie des secteurs escarpés en forme d'amphithéâtre dépend de l'épaisseur de la roche calcaire de couverture. Le long de quelques-unes des vallées sèches (type 'cheminée') ont été trouvés des spéléothèmes formés dans des grottes de type "fissure", exposées lors du recul de l'escarpement. Cette étude montre que l'analyse combinée, géomorphologique et structurale, des vallées sèches encaissées de montagnes calcaires peut fournir des informations utiles sur l’évolution et la morphologie de l’abrupt régressif sur lequel elles se développent

Farmed calcite δ13C at Ascunsă cave, Romania, and its relation with CO2 outgassing and drip rate

When calcite precipitates in caves, its carbon stable isotope signature can be modified by the CO2 outgassing gradient between drip water and cave atmosphere. This effect is modulated by the water residence time in the cave, from its emergence in the cave until the deposition of calcite. Moreover, CO2 solubility, calcite precipitation rate, and isotopic fractionation are controlled by temperature. Here, we present up to date results of an ongoing monitoring study at Ascunsă Cave (Romania), exploring the relationship between farmed calcite δ13C, drip rate, and CO2 outgassing. In addition to measuring CO2 concentration in cave air, we also measured the CO2 concentration in the headspace of a water-air equilibrator that collects drip water without exposing it to cave atmosphere, preventing outgassing. δ13C from calcite farmed at two neighboring stalagmites with different drip rates was also measured. Although caves have generally stable temperatures, we show here that temperature inside Ascunsă and Isverna caves has risen by more than 2°C over the course of a year, bearing important implications for stable isotopic fractionation equations and CO2 dynamics. Our results show that δ13C of farmed calcite has a strong relationship with drip rate at the slow dripping site, but no correlation at the faster dripping site. These two sites are also different when δ13C is compared to the outgassing gradient. At the slower drip site, δ13C and the outgassing gradient are directly correlated, whereas at the faster drip site their correlation is inverse. Our study brings new light onto speleothem δ13C behavior in general, and at Ascunsă Cave in particular, which is crucial for understanding the paleoclimate information captured by speleothems from this cave or elsewhere.Lorsque la calcite précipite dans les grottes, la signature isotopique en carbone peut être modifiée par le gradient de dégazage du CO2 entre l’eau de ruissellement et l’atmosphère de la grotte. Cet effet est modulé par le temps de séjour de l’eau dans la grotte, depuis son émergence dans la grotte jusqu’au dépôt de la calcite. De plus, la solubilité du CO2, le taux de précipitation de la calcite et le fractionnement isotopique sont contrôlés par la température. Dans cette étude, nous présentons des résultats actualisés d’une étude de suivi en cours dans la grotte d’Ascunsă (Roumanie), qui explore la relation entre les valeurs de δ13C de calcite déposée, le taux d’écoulement goutte-à-goutte et le dégazage du CO2. En plus de la mesure de la concentration de CO2 de l’air de la grotte, nous avons également mesuré la concentration de CO2 dans la partie supérieure d’un équilibreur eau-air qui collecte les gouttes d’eau sans les exposer à l’atmosphère de la grotte, empêchant ainsi le dégazage. Les valeurs modernes de δ13C de la calcite dans deux stalagmites voisines avec des débits d’écoulement goutte-à-goutte différents ont également été mesurées. Bien que les grottes aient des températures généralement stables, nous montrons ici que la température à l’intérieur des grottes d’Ascunsă et d’Isverna a augmenté de plus de 2°C en un an, ce qui a des implications importantes pour les équations de fractionnement d’isotopes stables et sur la dynamique du CO2. Nos résultats montrent que les valeurs de δ13C de la calcite et du taux d’écoulement goutte-à-goutte ne sont corrélées que dans le site ayant un débit goutte-à-goutte faible. Ces deux sites diffèrent également lorsque l’on compare les valeurs de δ13C avec le gradient de dégazage. À débit d’écoulement goutte-à-goutte lent, les valeurs de δ13C et le gradient de dégazage sont directement corrélés, alors que lorsqu’il est rapide, ces deux valeurs sont anti-corrélées. Notre étude apporte donc un nouvel éclairage sur le comportement des valeurs de δ13C des spéléothèmes en général, et dans les grottes d’Ascunsă en particulier, ce qui est crucial afin de comprendre les informations paléoclimatiques enregistrées par les spéléothèmes de ces grottes et d’autres

Caves as observatories for atmospheric thermal tides: an example from Ascunsă Cave, Romania

As part of a microclimate study at Ascunsă Cave, Romania, we used Gemini Tinytag Plus 2 data loggers to record cave air temperature variability. At one of the monitoring points we recognized the presence of semidiurnal cycles on the order of a few thousands of a degree Celsius that could be produced under the influence of the semidiurnal tidal components of the Sun (S2) or the Moon (M2). Using a Gemini Tinytag Plus 2 data logger with an external probe we measured core rock temperature and showed that it does not influence the cave air temperature on such short time scales. We thus rejected the possibility that Earth tides, mostly produced by the lunar tidal influence on the Earth’s crust, would have had a semidiurnal influence on cave air temperature. Moreover, time series analysis revealed a 12.00-hour periodicity in temperature data, specific for the S2, allowing us to assign these variations to the influence of the thermo-tidal action of the Sun. Using the Ideal Gas Law and assuming a constant volume and amount of air, we calculated that a theoretical change in atmospheric pressure of around 40 Pa was needed to produce the temperature changes we observed. This agrees with published values of atmospheric pressure changes induced by the semidiurnal solar component of the thermal tides (S2(t)). We thus can assign the observed temperature changes to semidiurnal atmospheric pressure changes (S2(p)) induced by the thermal excitation of the Sun. Our study signals the possibility that readily available data from cave monitoring studies around the world could be used in the study of atmospheric tides. Moreover, it appears that Ascunsă Cave acts as a natural meteorological filter on a short time scale, removing the direct thermal influences of the Sun (especially night and day differences) and preserving only the barometric information from the surface

Classification of longitudinal strain curves measured by speckle-tracking echocardiography in normal and pathological myocardial segments

Two-dimensional speckle-tracking echocardiography (2D-STE) provides a quantitative tool to evaluate LV function at the regional level. The purpose of this study was to classify the types of regional longitudinal strain curves (LSC). Moreover, we propose a novel longitudinal strain curve index (LSCI) which we compared to the wall motion score index (WMSI)