Hot Springs Research Articles

FEATURES OF FORMATION AND SEARCH FOR GROUNDWATER IN VOLCANIC REGIONS (BASED ON COMPREHENSIVE STUDIES OF THE DRAINAGE BASINS OF MOUNT ARAGATS MASSIF, RA)

Numerous targeted studies have been conducted in many regions of volcanism due to the exploitation of the Earth's natural heat, the use of thermal springs, and the search for mineral resources. Scientific and practical tasks are solved, in particular, during exploration and prospecting for water to meet water supply and irrigation needs. Increasing the efficiency of surveys and the reliability of the results obtained requires the improvement of search methods and techniques. Solving problems in volcanic regions is complicated by the fact that the sought-after marker horizons are mainly hidden under a thick cover of lava flows and sheets. This circumstance particularly necessitates the use of a combination of various research methods during water exploration and prospecting.

Metabolic interdependencies in thermophilic communities are revealed using co-occurrence and complementarity networks

Microbial communities exhibit intricate interactions underpinned by metabolic dependencies. To elucidate these dependencies, we present a workflow utilizing random matrix theory on metagenome-assembled genomes to construct co-occurrence and metabolic complementarity networks. We apply this approach to a temperature gradient hot spring, unraveling the interplay between thermal stress and metabolic cooperation. Our analysis reveals an increase in the frequency of metabolic interactions with rising temperatures. Amino acids, coenzyme A derivatives, and carbohydrates emerge as key exchange metabolites, forming the foundation for syntrophic dependencies, in which commensalistic interactions take a greater proportion than mutualistic ones. These metabolic exchanges are most prevalent between phylogenetically distant species, especially archaea-bacteria collaborations, as a crucial adaptation to harsh environments. Furthermore, we identify a significant positive correlation between basal metabolite exchange and genome size disparity, potentially signifying a means for streamlined genomes to leverage cooperation with metabolically richer partners. This phenomenon is also confirmed by another composting system which has a similar wide range of temperature fluctuations. Our workflow provides a feasible way to decipher the metabolic complementarity mechanisms underlying microbial interactions, and our findings suggested environmental stress regulates the cooperative strategies of thermophiles, while these dependencies have been potentially hardwired into their genomes during co-evolutions.

Technologies of the Integrated Development of Hydrogeothermal Resources of the North Caucasian Region

This paper focuses on the technologies of the integrated development of high-parametric geothermal brines with steam release. They differ from each other depending on initial parameters. Such way of brine utilization will make it possible to transform thermal energy to electrical power along with significant increasing its salinity that contributes to chemical components extraction. The opportunity is considered of this technology application in the Tarumovka geothermal field with electric power generation in steam-turbine and binary power plants, and consequent obtaining valuable mineral components. The geothermal and biogas technologies are given proposing integrated utilization of thermal water for various applications. Such systems make it possible to use resource potential of geothermal well and biomass that will result in improvement of economic and environmental situation in the North Caucasus region.

Efficient Bio-Based Insulation Panels Produced from Eucalyptus Bark Waste

Traditional thermal insulation panels consume large amounts of energy during production and emits pollutants into the environment. To mitigate this impact, the development of bio-based materials is an attractive alternative. In this context, the characteristics of the Eucalyptus fiber bark (EGFB) make it a candidate for insulation applications. However, more knowledge about the manufacturing process and in-service performance is needed. The present study characterized the properties that determine the in-service behavior of the EGFB insulation panel. The assessment involved two different manufacturing processes. The results indicated that the hot plates and the saturated steam injection manufacturing system can produce panels with similar target and bulk density. The thermal conductivity fluctuated between 0.064 and 0.077 W/m·K, which indicated good insulation, and the values obtained for thermal diffusivity (0.10–0.37 m mm2/s) and water vapor permeability (0.032–0.055 m kg/GN s) are comparable with other commercially available panels. To guarantee a good in-service performance, the panels need to be treated with flame retardant and antifungal additive. The good performance of the panel is relevant because bio-based Eucalyptus bark panels generate less CO2 eq and require less energy consumption compared to traditional alternatives, contributing to the sustainability of the forestry and the construction industry.

Experiences as heuristics for geothermal public perception: Testing the correlation between thermal waters recreation and geothermal energy perception

This research focuses on the question of how geothermal energy public perception is formed within a national context where news media do not pay attention to geothermal energy, and there is no active opposition to geothermal energy. The research builds on theoretical underpinnings of heuristics in energy perceptions and highlights the importance of physical experiences and associations as sources of experiential learning. Through a survey conducted among members of the general public in Slovenia, the role of thermal water recreation in shaping public perception of geothermal energy is empirically tested. The results show that, in this context, geothermal energy is highly positively assessed compared to hydro energy and nuclear energy, and that there is a correlation between frequency of thermal recreation and certain aspects of public perception of geothermal energy. The policy implications go beyond the simple recommendation of including tourism in public awareness campaigns but point to the specific vulnerability of energy acceptance in this context, where perceptions are formed based on “thinking fast”, and where the media and the public discourse on geothermal energy have not (yet) considered the potential risks and opposition to geothermal projects.

Geothermal resources of Hungary: a play-based review

In this paper we review the geothermal resources of Hungary using the geothermal play concept and its scale-dependent hierarchical categorization. The Pannonian Basin belongs to an extensional domain play type, with two main plays: the porous Neogene basin fill sediments and the fractured-karstified Palaeozoic and Mesozoic basement rocks. Both plays can be divided into hydrostatic and overpressured play segments. The most widely utilized play level in the hydrostatic segment of the porous Neogene sediment play comprises laterally extended highly permeable sandstone layers storing low salinity thermal water with average flow rate around 900 l/min and temperatures between 50 °C and 100 °C in the depth range of 1–2 km. The other prosperous play level is represented by the fractured-karstified Mesozoic carbonates in the hydrostatic segment of the basement play having elevated temperatures (90–120 °C) and several thousand l/min flow rates. The play level related to fractured Palaeozoic rocks is less important due to its limited extent. The overpressured segment of the basement play may have high flow rates, but still an untapped resource, where exploitation is limited by high overpressure, high temperature (170–200 °C), and highly saline hot waters.

Conceptual modelling on water-rock reaction and genesis of high pH fluids in a typical granitoid geothermal reservoir: A case from Indus-Tsangpo Suture Zone, India

Two novel thermal springs are investigated along ITSZ of north-west Himalayas in Demchok geothermal belt. The area consists of deep-seated faults in LGB; despite being situated in ITSZ, fluid chemistry of these low-temperature springs differs significantly, specifically in terms of low TDS (161–168 mg/l) and high alkalinity, with neighbouring springs in Puga and Chumathang (∼2100 mg/l). Thermal waters are mixed type (Na–Cl–HCO3–SO4) with elemental composition influenced through silicate rock weathering and partial carbonate dissolution. Variable temperature speciation (25 °C–200 °C) indicates that in reservoir fluid, Na+ precedes over other cations, while sulfate and carbonate complexes being prominent for Mg and Ca, respectively. Aquifer boiling modelling suggests calcite scaling and silica mineral equilibration in reservoir. Environmental stable isotopes (δ18O and δD) suggest high-altitude recharge from Jamlung La (6156 m), with altitude-effect of 0.43 ‰ isotopic depletion per 100 m elevation in altitude. As only silica minerals equilibrate with thermal waters, silica, and gas geothermometers give most conservative estimate of reservoir temperature (125°−135 °C). The steep topography enables extensive lateral flow of hot fluids in outflow zone, leading to high mixing and a high water-rock ratio, which contribute to lower TDS. Conceptual modelling reveals that geothermal system is a low-enthalpic hydrothermal system controlled by joints and permeable fractures, having deep fluid circulation of meteoric waters of ∼1275 m at sub-surface, with anomalous geothermal gradient and steam migration as reservoir heat sources. These fluids closely resemble springs of Guerrero state, Mexico, exhibiting similarities in low-TDS, high-pH, and high concentration of dissolved silica.

Thermal preconditioning of membrane stress to control the shapes of ultrathin crystals.

We employ the phospholipid bilayer membranes of giant unilamellar vesicles as a free-standing environment for the growth of membrane-integrated ultrathin phospholipid crystals possessing a variety of shapes with 6-fold symmetry. Crystal growth within vesicle membranes, where more elaborate shapes grow on larger vesicles is dominated by the bending energy of the membrane itself, creating a means to manipulate crystal morphology. Here we demonstrate how cooling rate preconditions the membrane tension before nucleation, in turn regulating nucleation and growth, and directing the morphology of crystals by the time they are large enough to be visualized. The crystals retain their shapes during further growth through the two phase region. Experiments demonstrate this behavior for single crystals growing within the membrane of each vesicle, ultimately comprising up to 13% of the vesicle area and length scales of up to 50 microns. A model for stress evolution, employing only physical property data, reveals how the competition between thermal membrane contraction and water diffusion from tensed vesicles produces a size- and time-dependence of the membrane tension as a result of cooling history. The tension, critical in the contribution of bending energy in the fluid membrane regions, in turn selects for crystal shape for vesicles of a given size. The model reveals unanticipated behaviors including a low steady state tension on small vesicles that allows compact domains to develop, rapid tension development on large vesicles producing flower-shaped domains, and a stress relaxation through water diffusion across the membrane with a time constant scaling as the square of the vesicle radius, consistent with measurable tensions only in the largest vesicles.

Genome-guided bioprospecting for industrially important enzymes from a thermophilic Bacillus subtilis strain SR-7, an isolate from hot spring of Madhya Pradesh, India

The study focused on isolating thermophilic bacteria from the hot springs of Madhya Pradesh, India, with the aim of identifying strains capable of producing industrially valuable enzymes. Among the 15 isolated strains, SR-7 identified as Bacillus subtilis exhibited significant enzyme activity, leading to its selection for further investigation. Genomic analysis revealed key characteristics of SR-7, including a 3,593,163 base pair chromosome with a GC content of 44.14 %. The genome was found to contain 55 tRNA genes, four rRNA clusters, and 3744 protein-coding genes. These genes encompass essential metabolic pathways and genes responsible for thermophilic adaptation, highlighting the potential for industrial applications. Further experimentation demonstrated SR-7 have the ability to produce various enzymes of industrial significance, such as amylase, lipase, cellulase, protease, lecithinase, gelatinase, and pectinase. Importantly, enzyme production was observed across a broad pH range (6.5 to 10) and temperature spectrum, indicating the versatility and adaptability of SR-7 to different environmental conditions. The findings suggest that SR-7 holds promise as a valuable resource for the pharmaceutical and industrial sectors. Its capacity to produce thermostable enzymes suitable for a range of applications underscores its potential contribution to biotechnological processes. By harnessing the enzymatic capabilities of thermophilic bacteria like SR-7, industries can pursue more sustainable and efficient production methods, reducing reliance on traditional chemical processes and enhancing overall productivity. Further research into the enzymatic properties and genetic mechanisms of SR-7 may unveil additional avenues for its utilization in various industrial processes.

Distribution and genesis of geothermal waters in the Xianshuihe fault zone, Western Sichuan plateau, China: Constraints on fracture system and regional seismic activities

The Xianshuihe fault zone (XSFZ), which is characterized by intense tectonic activities, frequent earthquakes and great number of hot springs, has significant potential for exploiting geothermal resources. Previous studies primarily focus on certain hydrothermal systems in southeastern segment of XSFZ, such as Kangding hydrothermal system, but lack the synthetical comparison and systematic analysis of geothermal waters along the XSFZ. Based on detailed geological investigation, the XSFZ hydrothermal system has divided into six geothermal activity areas: Luhuo (LH), Daofu (DF), Qianning-Bamei (QB), Yalahe-Zhonggu (YZ), Kangding (KD) and Moxi (MX). According to the 87Sr/86Sr ratios and elements behaving in water-rock interactions, the dissolution of silicate minerals is the primarily source of the hydrogeochemical compositions in geothermal waters. The δD and δ18O composition indicate that geothermal waters primarily originated from meteoric waters, but also affected by deep fluids. However, the contribution of deep fluids to the southeastern geothermal areas (YZ, KD and MX) with high concentrations of Cl- is greater than that of the northwestern (LH, DF and QB). The reservoir temperatures and chlorine-enthalpy model reveal that there are three distinct geothermal systems along the XSFZ: YZ and KD geothermal waters are originated from a common deep reservoir (R1), MX are from R3, and LH, DF, and QB are from R4. Due to the uneven thermal structural distribution along XSFZ, the southeastern segments generated stronger thermal stress and have more frequent earthquake occurrence. Thus, the study of geothermal waters along XSFZ can provide valuable insights into deep tectonic activities and geochemical indicators of earthquake monitoring in the region.

Development and characterisation of gluten‐free fresh pasta using teff, rice, and buckwheat flours enhanced with thermal waters: a mixture design approach

SummaryTo meet the demand for gluten‐free (GF) products, this study developed artisanal fresh pasta using teff, rice, and buckwheat flours, enhanced with mineral‐rich thermal waters (TW). A mixture design approach optimised flour proportions to balance texture, cooking time, water absorption, and cooking loss, along with functional properties such as total phenolic compounds (TPC) and antioxidant activity. Two promising formulations were identified: 36.3 g buckwheat, 9.35 g rice, and 9.35 g teff; and 27.5 g teff and 27.5 g buckwheat. These formulations, with and without TW, were evaluated for chemical, technological, microbiological, and functional attributes. The pasta had satisfactory technological properties, macronutrient levels comparable to standard pasta, and was rich in phenolic compounds with antioxidant activity. Ca, Zn, Fe, K, and Mn were predominant, although TW incorporation did not significantly affect their levels in the samples. All formulations showed microbiological stability for at least 3 days at 4 °C.

Exploration of Thermophilic Lignocellulolytic Enzymes Producing Bacterial Strains from Hot Springs of Western Himalayan Range

Exploration of Thermophilic Lignocellulolytic Enzymes Producing Bacterial Strains from Hot Springs of Western Himalayan Range

Sources, enrichment mechanisms, and resource effects of rare metal elements-enriched geothermal springs in Xizang, China

Sources, enrichment mechanisms, and resource effects of rare metal elements-enriched geothermal springs in Xizang, China

Dynamics of Scutellaria tuvensis (Lamiaceae) coenopopulations

The dynamics of density, abundance, ontogenetic structure and spatial organization of Scutellaria tuvensis coenopopulations under the influence of climatic factors in different habitat conditions has been studied. The decrease in the climate aridity in the basins of the Republic of Tuva in the last 10 years has a positive effect on the condition of the coenopopulations of S. tuvensis, occurring in dry and deseritied steppes. The coenopopulations of S. tuvensis are normal, stable, and in balance with the ecotope. The dynamics of the number, ecological density, spatial distribution of individuals in the coenopopulations, and the type of ontogenetic spectrum are influenced by climatic factors, while the values of demographic indicators in the coenopopulations are determined by the peculiarities of development of individuals in different habitats. Under a mildening climate (early warm spring and non-dry summer), optimal conditions are created for seed germination and further development of young plants. Recently, an increase in the number of young plants has been found in all habitats, a left-sided type of the ontogenetic spectrum is being formed, and coenopopulations are rejuvenating.

Production and biological activities of exopolysaccharides synthesized by thermophilic bacilli isolated from hot springs in Türkiye.

Thermophilic bacteria able to produce exopolysaccharides (EPSs) have become attractive in recent years. EPSs synthesized by thermophiles are worth investigating due to their unexplored structural and biological properties. In this study, EPSs from thermophilic, Gram-positive bacterial isolates were purified and tested for their biological activities. A total of one hundred seven thermophilic bacteria were screened for their ability to produce exopolysaccharides. Nine isolates belonging to Geobacillus, Parageobacillus, Aeribacillus, and Anoxybacillus genera with highest EPS production were chosen, and purified EPSs (20, 61, 74, 76, 78, 89, 106, 134, and 261) were used for biological activity studies. EPS yields of selected thermophilic bacteria ranged between 117 and 419mg/L. Among the tested EPSs, 61, 106, and 261 showed antibacterial effect against E. faecalis JH2-2 at a final concentration of 1.5mg/mL. EPS samples had significantantioxidant capacity, especially EPS 134, with the highest DPPH radical scavenging activity of 100% at a concentration of 5mg/mL and the strongest reducing power.EPS 20 showed the highest lipid peroxidation inhibition effect at a rate of 31%. EPSs displayed weak alpha-amylase inhibition activity when compared with standard acarbose. The prebiotic indices of EPSs 20, 61, 76, 89, 134, and 261 were found to be higher than that of inulin, a representative prebiotic carbohydrate for all tested lactic acid bacteria in the study. All examined EPSs inhibited the biofilms formed by various bacteria depending on the test strain. Results indicated that thermophilic EPSs had remarkable antioxidant, prebiotic, and antibiofilm activities. Therefore, EPSs characterized in this study may have technological applications in health and food fields.

Travel patterns and spatial structure: understanding winter tourism by trajectory data mining

ABSTRACT Mining tourists’ spatiotemporal patterns are fundamental for comprehending and applying spatial structure theories in tourism research. This study mines 27,981 tourist-generated trajectories in Beijing winter tourism to reveal the spatiotemporal patterns and spatial structures using a framework combining similarity measures and improved density-based spatial clustering of applications with noise algorithm. The findings indicate that Beijing winter tourism has established a spatial structure consisting of “three poles-two axes-two secondary poles.” A total of 50 popular routes and 12 patterns of winter tourism can be categorized into three main types and six subcategories: winter tourism leading (skiing oriented, skating oriented), winter tourism with sightseeing (urban snow scene sightseeing, mountain snow scene sightseeing), and winter tourism with leisure (skiing + hot spring therapy, skating + city walking). The findings demonstrate that identifying spatial structures through tourism pattern mining is scientific and feasible. This study examines the movement patterns of tourists to reveal tourism spatial structure and incorporates spatial geography theory to assure the accuracy and scientific validity of the identification process, which enables a comprehensive knowledge of the spatial structure of Beijing's winter tourism industry and broadens the application scenario of spatial geography theory in the era of big data.

Plio-Pleistocene hydrothermal events of the Baza Basin (Betic Cordillera, SE Spain) and their paleoecological implications

AbstractThe Lower Pliocene to upper Middle Pleistocene continental sedimentary infillings of the Baza Basin (Guadix-Baza Depression, SE Spain) are worldwide unique by their high stratigraphic completeness and exceptional preservation of their fossil record of terrestrial vertebrates. These sediments were deposited in fluvio-lacustrine environments and preserve huge assemblages of large mammals, including the oldest evidence of hominin presence in Western Europe at the late Lower Pleistocene sites of Barranco León and Fuente Nueva-3, dated to ∼1.4 Ma. Since latest Miocene times, the basin was subject to intense tectonic activity, showing sedimentary deposits originated from ancient hot springs. These hot springs were developed in a spatio-temporal network related to tectonic fractures, showing a higher concentration in the Orce sub-basin during Late Pliocene to Holocene times. Compositional analyses of cherts and other facies associated with these hot springs show geochemical and mineralogical markers linked to hydrothermal scenarios. The contribution of hot springs in the Baza Basin resulted in rich and productive biotopes, which supported a high diversity and biomass of terrestrial mammals. Similar geological, hydrochemical and ecological environments are found along hotspot lines in East Africa, the Levantine Corridor and the circum-Mediterranean realm. We hypothesize here that the presence of these hot springs corridors favored the dispersal of hominins and other large mammals during the Plio-Pleistocene, which led to the first hominin arrival in Europe.

New Viruses Infecting Hyperthermophilic Bacterium Thermus thermophilus.

Highly diverse phages infecting thermophilic bacteria of the Thermus genus have been isolated over the years from hot springs around the world. Many of these phages are unique, rely on highly unusual developmental strategies, and encode novel enzymes. The variety of Thermus phages is clearly undersampled, as evidenced, for example, by a paucity of phage-matching spacers in Thermus CRISPR arrays. Using water samples collected from hot springs in the Kunashir Island from the Kuril archipelago and from the Tsaishi and Nokalakevi districts in the Republic of Georgia, we isolated several distinct phages infecting laboratory strains of Thermus thermophilus. Genomic sequence analysis of 11 phages revealed both close relatives of previously described Thermus phages isolated from geographically distant sites, as well as phages with very limited similarity to earlier isolates. Comparative analysis allowed us to predict several accessory phage genes whose products may be involved in host defense/interviral warfare, including a putative Type V CRISPR-cas system.

Chemical and isotopic constraints on fluid origin and genesis of geothermal systems in the Tingri-Tangra Yumco rift, southern Tibetan Plateau

Numerous geothermal systems are hosted by extensional rifts that transect the Himalayas and Lhasa block in the Himalayan–Tibetan orogen. However, the relationships between hydrogeological processes and geothermal fluid circulation in different tectonic units remain unclear. Here, we report an integrated dataset of chemical and isotopic compositions (including major and trace elements, δD, δ18O, and 87Sr/86Sr) of thermal spring water from the Tingri-Tangra Yumco rift to assess their origins and circulation processes. δ18O (− 21.3 to − 17.0‰) and δD (− 166 to − 135‰) values of thermal springs indicate dominant recharge of meteoric waters from areas with elevation of > 6000 m and minor addition of magmatic fluids. Meteoric water could infiltrate to depths of about 1700–2900 m along the faults, whereby it is influenced by geothermal gradient and/or conductive heat transfer of magmatic fluids. The thermal spring waters are mainly Na-HCO3 type and are controlled by dissolution of silicate and carbonate minerals and mixing with deep fluids. The results of chemical and multicomponent geothermometers indicate reservoir temperatures of 115 − 195 ℃, corresponding to a convection heat flux of 3.96 × 105 J/s to 1.78 × 107 J/s from geothermal systems, which are comparable to that of the low-enthalpy geothermal systems in southern Italy. Geochemical modeling is conducted to assess the water–mineral equilibria in the reservoir. Trace elements and 87Sr/86Sr data suggest spatially variable controlling factors for the rift-related geothermal systems: (1) interaction with granitoid and carbonate in the Himalayas; (2) cold groundwater mixing with that leaching from granite and volcanic rocks in the Lhasa block; (3) the input of vapors from magmatic degassing. The geochemistry of thermal springs associated with extensional rift is largely induced by the interaction between fluid and different reservoir rocks in the Himalayas and Lhasa block. Based on these findings, a genetic model is proposed for exploration and development of geothermal resources in the Tingri-Tangra Yumco rift.

Biodegradable and active film based on keratin and protein hydrolysate of free-range chicken feathers: Structural and antioxidant properties

Keratin can be applied in developing films for food packaging due to its biodegradable and non-toxic nature. It can be extracted from chicken feathers and used as a source of protein to obtain peptides with technological properties of interest to the food industry. Therefore, this study aimed to elaborate on an active film with keratin and protein hydrolysate extracted from the feathers of free-range chicken. Four treatments were elaborated: F0 - control film without the addition of protein hydrolysate; F1 - film with the addition of 1.5% of protein hydrolysate; F3 - film with the addition of 3.0% protein hydrolysate and F6 - film with 6.0% protein hydrolysate. The films were evaluated for optical and thermal properties, water solubility, degradability, and antioxidant potential. The influence of hydrolysate addition on mechanical properties, solubility, and permeability to water vapor was observed. The percentage of degradability and the ABTS antioxidant potential was higher in the F6 treatment than the others.Regarding thermal analyses, the films presented high stability, which was associated with keratin thermal resistance. The present study points out that producing active films from free-range chicken feathers is an alternative to reducing the by-products and the use of plastics harmful to the environment. The F6 formulation is recommended for use by the active packaging industry because it presents the highest antioxidant activity and tensile strength but lower permeability to water vapor.