Since the start of mass production of plastic materials more than a century ago, the problem of accumulating plastic waste in the environment has reached epic proportions. Recently, the problem of ...smaller plastic particles (microplastic, MP) in the environment has become a widely studied topic, but the amount and types of MP in karst environments are still poorly known. Thus, the objective of this study was to collect and analyse samples from various karst habitats and to try and determine the scope of pollution in karst springs that are in part used as sources for drinking water. Of the potential pollution sources, we sampled rainwater, two discharges from wastewater treatment plants, and a leachate from a landfill. We conducted polymer analyses of potential MP particles using FTIR-ATR. The results showed that eight samples from the Postojna region (Postojna–Planina Cave System, rainfall sample and surface streams) contain up to 444 MP particles per m3. However, 32 samples taken from the Škocjan–Kačna–Jama 1 v Kanjaducah Cave System contain up to 60,000 MP particles per m3, with the bulk of particles found in the sediment samples from Škocjan Caves – Kačna Cave System. Samples from Postojna region contained mostly PET, PU and PA polymers, with a minor inclusion of polymers of plastic sponge used for cleaning. Samples from Škocjan region contained mostly PP, PET and PE polymers, with some of PA and PU polymers. Sediment samples contained much less MP particles compared to water samples, which indicates fast transport through karst aquifer.
The aquifers of alpine karst and high karst plateaus are abundant water resources. They are difficult to characterise due to their complex, partly glaciokarstic, evolution in active tectonic ...environments, and an unsaturated zone up to two kilometres thick. We present and discuss the results of a tracing test in the alpine karst of the Julian Alps (Slovenia), more precisely in the Migovec System, the longest cave system in Slovenia (length = 43 km, depth = 972 m). The cave extends below a mountain ridge that separates the Soča and Sava Valleys, thus forming a topographic divide between the Adriatic and Black Sea basins, which gives the test greater regional significance. In early September 2019, three kilograms of uranine were injected into a perched lake in a remote part of the system, approximately 900 metres below the plateau and 100 metres above the low water table. All known springs in the valleys on either side of the mountain were monitored by manual or instrumental sampling and a field fluorometer. Due to the unexpectedly dry season, no tracer was detected at any site for two months until a heavy rainfall event in early November. Subsequently, about 60-65 % of the tracer mass appeared within 60 hours in the Tolminka River. No tracer was detected at other sites, either becauseit was not present or because it was highly diluted. The study suggests that the lake containing the tracer is bypassed by the vadose flow and that the tracer was only mobilised during large events when the lake became part of the epihreatic flow. The linear peak flow velocity from the injection site to the Tolminka Spring was only about 1.7 m/h. However, assuming that the tracer was only mobilised by the large rain event, the velocity would be 70 m/h. The study highlights the challenges and pitfalls of water tracing in alpine karst systems and suggests ways to avoid them.
The study of subterranean life in general and cave life in particular has been given several names, most especially biospeleology and speleobiology. Historically, biospeleology came first, and ...signalled that biological study was part of speleology, the science of caves. Speleology itself has come to have several meanings beyond the science of caves, but as a discipline it has not fully developed. Speleobiology emphasizes the connection with biology, especially ecology and evolutionary biology. Biospeleology can be construed as the taxonomic and distributional aspects of the biology of caves while speleobiology can be construed as the aspects pertaining to general biological principles such as evolution.
Abiotic and biotic factors, especially microorganisms, play a role in the development of cave formations and the existence of unique characteristics of each cave. Due to the ecological conditions ...that characterize the cave environments, highly specialized microorganisms that are the main source of diverse bioactive compounds, inhabit these environments. The aim of this study is to determine the role and biotechnological potential of the bacteria isolated from Yarık Sinkhole located in Antalya (Turkey) by screening their ability to induce the CaCO3 precipitation, to hydrolyze urea, to induce calcite dissolution, and screening their possession of NRPS/PKS gene clusters. The most prevalent phylum is the Bacillota (synonym Firmicutes) (75.7 %), while the dominant species is Bacillus pumilus (33 %). All the isolates showed crystal formation on B4 agar medium, and the Energy dispersive X-Ray spectroscopy (EDS) analyses showed that the crystals are predominately composed of calcium, carbon and oxygen. Ninety-six (96 %) of our isolates have negative ureolytic activity. According to this result and having the ability to induce the CaCO3 precipitation, bacteria in this environment use other biosynthesis pathways than urea hydrolysis. MgCO3 and CaCO3 were dissolved by 61 % and 59 % of the isolates, respectively. In addition, 5.9 % and 53.7 % of the isolates showed the possession of PKS and NRPS genes, respectively. This result reveals that our isolates have high industrial and biotechnological potential. They may constitute good candidates for further biotechnological applications such as construction of bio-concretes, bioremediation, soil fertility, and production of biologically active secondary metabolites.
Proper water resources management requires recognizing and evaluating the factors that affect the quantity and quality of water resources. The Ilam-Sarvak (Upper Cretaceous) and Asmari (Oligocene to ...Miocene) limestone- dolomite formations in the Zagros structural belt have formed a promising karst groundwater horizon. In the present study, the hydraulic relationship between the karst structures of the Izeh territory in the northeast of Khuzestan province was investigated using hydrogeochemical and isotopic information of springs and wells. The results enabled to understand various components influencing the recharge of water resources. In this study, samples were collected from the karst springs and wells of Mongasht, Shavish-Tanosh and Kamarderaz anticlines and Naal-e-Asbi (Horseshoe) syncline and meteoric water to understand the hydrochemical and isotopic characterization, and hydrogeological and hydraulic behavior of the Izeh karst system. The meteoric and groundwater samples were analyzed to determine major and minor ion concentrations and δ18O and δ2H isotope ratios. Isotopic content ranged from -31.6 to -2.9‰ and from -6.32 to -1.87‰ for δ2H and δ18O, respectively, and d-excess values were high and positive. The study of the isotopic content of water samples of springs and wells in the region shows three groups of water sources. The first group, related to the Mongasht anticline springs, has lower isotopic values, indicating that it is recharged by rainfall at high altitudes and snow melting. The isotopic value of the second group is richer than that of the first group, indicating rainfall recharge as well as groundwater mixing (examples of Naal-e-Asbi syncline and Shavish-Tanosh anticline). The highest value in the third group (samples of Kamarderaz anticline) is attributed to evaporation and longer distance from the recharge site to the discharge point, as well as to the diffusion system. The trend of decrease in Sr+2 and increase in Ba+2 in the samples of dolomitic limestone formations (Shavish Tanosh and Mongasht anticlines) compared to the water samples of Kamarderaz anticline and Naal-e-Asbi syncline indicates the possibility that karst aquifers of the region are recharged from the Mongasht anticline and that there is a hydraulic relationship between these structures. D-excess and δ18O show a linear trend, illustrating the effect of altitude difference on isotopic content and recharge sources. The major and minor changes in the concentration of ions, the isotopic content of groundwater and the relationship between TDS and δ18O and d-excess and δ18O indicate the mixing and recharging of karst aquifers (Shavish-Tanosh, Kamarderaz and Naal-e-Asbi aquifers) from the Mongasht karst aquifer and their hydraulic connection.
Microclimate conditions, mainly radiation, temperature and relative humidity vary according to cavities´ configurations and determine the microorganism’s colonisation. A meta-analysis was performed ...of environmental factors influencing the algal species colonisation in caves and rockshelters. For this purpose, the results of studies about algal colonisation in 82 caves and rockshelters in 11 European, Asian and American countries were analysed. Firstly, 412 species were counted of which Cyanobacteria predominated, followed by Chlorophyta and Bacillariophyta, and finally by Rhodophyta. The Shannon Index determined that the diversity of the algal species developing in these places was very high. The most diverse Cyanobacteria genera to appear in the different studied caves and rockshelters are Leptolyngbya with 28 different species, Gloeocapsa with 24 and Phormidium with 23. They are followed by Chroococcus with 18, Aphanothece with 14, Oscillatoria, Nostoc and Scytonema with 10 each and Schizothrix and Tolypothrix with 9 each. The most diverse Chlorophyta and Bacillariophyta genera are Chlorella with 9 different species and Diadesmis/Humidophila, Luticola and Nitzschia with 4, respectively. The principal component analysis revealed that both photosynthetically active radiation and relative humidity more actively conditioned the development of some algal species in cave environments than temperature.
The development of emerging hollowing parts of the main channels of rinnenkarren systems at tributary channel junctions is interpreted in this study using Computational Fluid Dynamics (CFD) ...simulation. In the field, data from cross-sections of 505 local hollowings with one or more tributary channel junctions were investigated. The shift in the width–depth ratio of the local hollowings was studied as the number of junctions and the size of the hollowing changed. Flow was simulated through CFD in digital model channels, and the nature of the resulting vorticity was interpreted. Field data show that local hollowings emerging in the main channels of the channel systems at the junctions. In the main channels, when only a few tributary channels join in the vicinity of each other, local hollowings deepen during their growth and, most often, gradually become pits (depth is larger than width), as the morphometric analysis suggests. As the number of tributary channels increases, the local hollowing may develop into a kamenitza (width is larger than depth). The model experiment suggests the explanation that more tributary channel junctions result in more extensive vorticity, which contributes to the lateral extension (widening) of this channel section. The distance of the tributary junctions from each other also influences the downstream dimension of the local hollowing. In the field, the larger this distance, the more separated the local hollowings induced by individual tributaries. The model experiment suggests that this may occur because the intense vorticity generated by individual junctions becomes increasingly sectionalized as the tributary channel density decreases.
A 13-month monitoring was carried out in two caves that open up in the north-western sector of the Classical Karst (Gorizia Karst): Antro Casali Neri and Grotta Due Piani. In both, ß + γ ...radioactivity, radon and CO2 have a seasonal pattern, with maximums in summer and minimums in winter, even if their trends are somewhat different, due to the different morphological and thermal conditions. The increases begin when the outside temperature becomes higher than that of the caves and vice versa, decrease is recorded when outside temperature is below the cave temperature. The more modest daily variations of radon, on the other hand, are evident when its concentration is low. Sometimes they are related to meteorological variations or day/night rhythms, but, in other cases, they have no clearly identifiable causes. In Casali Neri cave the maximum radon activity was 50161 Bq/m3, while the CO2 concentration went off the instrument's scale (> 9999 ppm) only in the first days of August 2021. The highest radioactivity value was also recorded in this cave with 0.85 μSv/h (average of 8 minutes of recording), with peaks up to 1.05 μSv/h. In Due Piani cave, on the other hand, the radon activity was lower, with a maximum of 22138 Bq/m3, however, the CO2 values went off the scale from July to the first days of October 2021. In both cases, in the warm months, radon and CO2 appear to come mainly from the fractured rock of epikarstic zone. Further accumulations can then form in points with poor ventilation. Furthermore, research has shown that high concentrations of these two gases are not only typical of large or deep caves, but also of modest and easily accessible caves.
