Hot Springs Research Articles

Hydrothermally synthesized cobalt oxide/polydimethylsiloxane based photothermal absorber for superior thermal energy conversion and water evaporation application

Solar-driven interfacial evaporation has garnered worldwide interest in recent years due to its unique vapor generating capacity using sustainable solar energy. Many photoabsorber have been studied for conversion of photothermal energy and heat absorption. Unfortunately, the majority of the absorber materials in supply are pricey, and the installation procedures tend to be intricate. This research focuses on the ongoing difficulty of creating cost-efficient photothermal materials that have excellent light absorption and simple manufacturing processes. We created a novel composites coated with Cobalt oxide and polydimethylsiloxane (Co3O4/PDMS) which successfully produce energy and purify water utilizing an extensive spectrum of solar energy. Hydrothermally synthesized Co3O4 particles exhibit distinct optical properties in the UV–Vis region due to ligand field transitions and charge transfer between Co2⁺ and Co³⁺ ions. Additionally, these particles exhibits a strong absorption in the NIR region due to the intervalence charge transfer and d-d transitions, enhancing their photothermal activity. This culminates in outstanding light-to-heat transformation in the Co3O4/PDMS composite, which maintains a surface temperature of 42.7 °C compared to 33.7 °C for pristine PDMS under standard 1 sun intensity for 5 min. The flexible Co3O4/PDMS composite transfers solar energy to electric energy, producing ∼99 mV with 1 sun irradiation, while bare PDMS only achieved a voltage of 61 mV under 1 sun circumstances. An efficient double layer Co3O4/PDMS@MF sponge achieved an evaporation rate of 1.33 kg m−2 h−1 with the photothermal conversion efficiency of 68.8 %. These results motivate thorough investigation in photothermal potential of Co3O4, revealing the promising possibilities for harnessing solar-thermal energy and presents a novel method for using solar power to purify water and generate electricity.

Monitoring Meat Freshness with Intelligent Colorimetric Labels Containing Red Cabbage Anthocyanins Copigmented with Gelatin and Gallic Acid.

Polyvinyl alcohol (PVA)-based pH-responsive color indicators were developed using red cabbage anthocyanin (Anth) copigmented with gelatin and gallic acid (GA). The indicator prepared with gelatin and GA (GA/gelatin/Anth/PVA) was highly resistant to light exposure. GA/gelatin/Anth/PVA exhibited distinct color changes in pH 2-11 buffer solutions and stable color indication in acidic and neutral solid systems (pH 2 and 7) at 97% relative humidity. GA/gelatin/Anth/PVA exhibited the highest sensitivity to dimethylamine, followed by ammonia and trimethylamine. The addition of gelatin and GA facilitated hydrogen bonding, which enhanced thermal stability and water solubility without compromising tensile properties. A color change from purple to blue signaled spoilage when total volatile basic nitrogen values for beef and squid reached 21.0 and 37.8 mg/100 g, respectively. The GA/gelatin/Anth/PVA indicator shows potential for indicating the freshness of raw beef.

Draft genome sequence of a cyanobacterium Gloeocapsa sp. BRSZ, isolated from Bo Khlueng hot spring in Ratchaburi, Thailand.

We report the draft genome sequence of Gloeocapsa sp. BRSZ isolated from Bo Khlueng hot spring in Thailand, comprising 42 contigs assembled at the scaffold level, totaling 6,084,403 bp, with 43.5% G + C content. It contains 5,456 putative protein-coding genes, including genes responsible for biosynthesis of mycosporine-like amino acids.

A conceptual and numerical model of fluid flow and heat transport in the Topusko hydrothermal system

Comprehensive understanding of hydrothermal systems is often obtained through the integration of conceptual and numerical modelling. This integrated approach provides a structured framework for the reconstruction and quantification of fluid dynamics in the reservoir, thereby facilitating informed decision-making for sustainable utilisation and environmental protection of the hydrothermal system. In this study, an updated conceptual model of the Topusko hydrothermal system (THS; central Croatia) is proposed based on structural, geochemical, and hydrogeological analyses. The stratigraphic sequence and the structural framework of the THS were defined based on geological maps and field investigations. As depicted by hydrochemical and isotope analyses, thermal waters in Topusko (temperatures of up to 65 °C) are of meteoric origin and circulate in a carbonate aquifer. The THS receives diffuse recharge approximately 13 km S from Topusko, where Triassic carbonates crop out. Gravity-driven regional groundwater circulation is favoured by regional thrusts that tectonically uplifted Palaeozoic low permeable rocks. These structures confine the fluid flow in the permeable, fractured and karstified, Triassic carbonates favouring the northward circulation of the water. A regional anticline lifts the aquifer closer to the surface in Topusko. Open fractures in the anticline hinge zone increase the fracturing and permeability field of the aquifer promoting the quick upwelling of the thermal water resulting in the Topusko thermal springs. Numerical simulations of fluid flow and heat transport corroborate the proposed conceptual model. In particular, a thermal anomaly was modelled in the Topusko subsurface with temperature values of 31.3 °C and 59.5 °C at the surface and at the base of the thermal aquifer, respectively, approaching the field observations. These findings showed that the circulation of Topusko thermal water is influenced by regional and local geological structures suggesting that the enhanced permeability field in the discharge area enables the formation of the natural thermal springs.

Changes of lifestyle and mental health among COVID-19 situation: resident-centered health promotion

Abstract Background Yuzawa town, located in the Niigata prefecture of Japan, is famous for its hot springs and ski resorts. A sustainable action plan for resident-centered regional health promotion (Yuzawa family health plan) was initiated in 2002. Surveys have been conducted every five years. This study aims to evaluate changes of their habits and mental health status between in 2017 and in 2022. Methods The survey of Yuzawa family health plan was conducted in 2017 and in 2022. Questionnaires were composed with living alone, living with marriage partner, living with son or daughter, living with grandchildren, living with brother or sister, health consciousness, attention to health, health concern, awakening in a morning, clockwork life, fitness habits, smoking, taking alcohol, anxiety, loneliness, consultation, resolve suffering, economic problem, handle stress, taking a rest, risk breaching, communication, life satisfaction, talking with family, job at home, intercommunion with friends, greeting with neighbors, relationship with neighbors, occupations, good sleep, taking breakfast, nutritional balance, mastication status, confirmation of food compositions, exercise habits, yearly health check-up, dental check-up, brushing teeth habits, and sleep satisfactions. Chi square tests were used to evaluate changes between in 2017 and in 2022. This study was approved by the ethics committee of Tokyo Women’s Medical University. Results Passive smoking, intercommunions with neighborhood and friends, exercises, and Salt reduction awareness reduced in 2022. Talking with family, taking a rest, attention to health, clockwork life, and sleep satisfactions increased. Conclusions Many changes were shown between in 2017 and in 2022. Because elderly has been able to use a mobile phone, loneliness was not increased. But numbers of elderly living alone have been increased from 2002. Health promotion programs giving health information for elderly is needed. Key messages • Many lifestyle changes were shown between in 2017 and in 2022. • Passive smoking reduced. Taking a rest and attention to health increased.

Phenological response to climatic change depends on spring warming velocity

Climatic change is dramatically altering phenology but generalities regarding tempo and mode of response remain limited. Here we present a general model framework incorporating spring temperature, velocity of spring warming, and species’ thermal requirements for predicting phenological response to warming. A key prediction of this framework is that species active earlier in the season and located in warmer regions where spring temperature velocity is lowest show strongest sensitivity to climatic change and greatest advancement in response to warming. We test this prediction using plant phenology datasets collected in the 1850s and 2010s. Our results strikingly confirm model predictions, showing that while temperature sensitivity is higher in regions with low temperature velocity, the greatest realized change in phenological onset is northern areas where warming rates have been fastest. Our framework offers enhanced utility for predicting phenological sensitivity and responsiveness in temperate regions and across multiple plant species and potentially other groups.

Seasonal Variations in the Thermal Stratification Responses and Water Quality of the Paldang Lake

We evaluated the thermal and chemical stratifications of Paldang Lake using Schmidt’s stability index (SSI) and the chemical stratification index (IC-i) with weekly data from 2013 to 2022. The temporal trends of stratification were analyzed alongside correlations with meteorological, hydrological, and water quality variables. Thermal stratification intensified with rising air temperature and sunshine duration, while hydrological factors like discharge and retention time affected SSI during periods with less than five days of water retention. During summer, fewer occurrences of intense rainfall or early rainfall before August led to stronger stratification. In fall, nutrient influx from external sources during summer stimulated algal growth, increasing Chlorophyll-α (Chl-α) concentrations. Summer rainfall had a significant impact on the strength and duration of stratification in Paldang Lake. Annual rainfall patterns and subsequent changes in discharge were key factors affecting the physical environment of the lake, which in turn determined water quality and the extent of algal blooms. We provide insights into the seasonal stratification and water quality variations in temperate river-type reservoirs like Paldang Lake. SSI and IC-i from this research can be applied to understand stratification and mixing dynamics in other lakes.

Aquificae overcomes competition by archaeal thermophiles, and crowding by bacterial mesophiles, to dominate the boiling vent-water of a Trans-Himalayan sulfur-borax spring.

Trans-Himalayan hot spring waters rich in boron, chlorine, sodium and sulfur (but poor in calcium and silicon) are known based on PCR-amplified 16S rRNA gene sequence data to harbor high diversities of infiltrating bacterial mesophiles. Yet, little is known about the community structure and functions, primary productivity, mutual interactions, and thermal adaptations of the microorganisms present in the steaming waters discharged by these geochemically peculiar spring systems. We revealed these aspects of a bacteria-dominated microbiome (microbial cell density ~8.5 × 104 mL-1; live:dead cell ratio 1.7) thriving in the boiling (85°C) fluid vented by a sulfur-borax spring called Lotus Pond, situated at 4436 m above the mean sea-level, in the Puga valley of eastern Ladakh, on the Changthang plateau. Assembly, annotation, and population-binning of >15-GB metagenomic sequence illuminated the numeral predominance of Aquificae. While members of this phylum accounted for 80% of all 16S rRNA-encoding reads within the metagenomic dataset, 14% of such reads were attributed to Proteobacteria. Post assembly, only 25% of all protein-coding genes identified were attributable to Aquificae, whereas 41% was ascribed to Proteobacteria. Annotation of metagenomic reads encoding 16S rRNAs, and/or PCR-amplified 16S rRNA genes, identified 163 bacterial genera, out of which 66 had been detected in past investigations of Lotus Pond's vent-water via 16S amplicon sequencing. Among these 66, Fervidobacterium, Halomonas, Hydrogenobacter, Paracoccus, Sulfurihydrogenibium, Tepidimonas, Thermus and Thiofaba (or their close phylogenomic relatives) were presently detected as metagenome-assembled genomes (MAGs). Remarkably, the Hydrogenobacter related MAG alone accounted for ~56% of the entire metagenome, even though only 15 out of the 66 genera consistently present in Lotus Pond's vent-water have strains growing in the laboratory at >45°C, reflecting the continued existence of the mesophiles in the ecosystem. Furthermore, the metagenome was replete with genes crucial for thermal adaptation in the context of Lotus Pond's geochemistry and topography. In terms of sequence similarity, a majority of those genes were attributable to phylogenetic relatives of mesophilic bacteria, while functionally they rendered functions such as encoding heat shock proteins, molecular chaperones, and chaperonin complexes; proteins controlling/modulating/inhibiting DNA gyrase; universal stress proteins; methionine sulfoxide reductases; fatty acid desaturases; different toxin-antitoxin systems; enzymes protecting against oxidative damage; proteins conferring flagellar structure/function, chemotaxis, cell adhesion/aggregation, biofilm formation, and quorum sensing. The Lotus Pond Aquificae not only dominated the microbiome numerically but also acted potentially as the main primary producers of the ecosystem, with chemolithotrophic sulfur oxidation (Sox) being the fundamental bioenergetic mechanism, and reductive tricarboxylic acid (rTCA) cycle the predominant carbon fixation pathway. The Lotus Pond metagenome contained several genes directly or indirectly related to virulence functions, biosynthesis of secondary metabolites including antibiotics, antibiotic resistance, and multi-drug efflux pumping. A large proportion of these genes being attributable to Aquificae, and Proteobacteria (very few were ascribed to Archaea), it could be worth exploring in the future whether antibiosis helped the Aquificae overcome niche overlap with other thermophiles (especially those belonging to Archaea), besides exacerbating the bioenergetic costs of thermal endurance for the mesophilic intruders of the ecosystem.

Unveiling a novel exopolysaccharide produced by Pseudomonas alcaligenes Med1 isolated from a Chilean hot spring as biotechnological additive

Exopolysaccharides (EPSs), a constitutive part of bacterial biofilm, act as a protecting sheath to the extremophilic bacteria and are of high industrial value. In this study, we elucidate a new EPS produced by thermotolerant (growth from 34–44 °C) strain Pseudomonas alcaligenes Med1 from Medano hot spring (39.1 °C surface temperature, pH 7.1) located in the Central Andean Mountains of Chile. Bacterial growth was screened for temperature tolerance (10–60 °C) to confirm the thermotolerance behaviour. Physicochemical properties of the EPS were characterized by different techniques: Scanning Electron Microscopy- Energy Dispersive X-ray Spectroscopy (SEM-EDS), Atomic Force Microscopy (AFM), High-Performance Liquid Chromatography (HPLC), Gel permeation chromatography (GPC), Fourier Transform Infrared Spectroscopy (FTIR), Nuclear Magnetic Resonance (NMR), and Thermogravimetric analysis (TGA). Whole genome of P. alcaligenes Med1 has also been studied in detail to correlate the structural and functional characteristics with genomic insight. The EPS demonstrated amorphous surface roughness composed of evenly distributed macromolecular lumps composed of mainly carbon and oxygen. The monosaccharide analysis has shown the presence of glucose, galactose, and mannose sugars at different ratios. TGA revealed the high thermal stability (315.3 °C) of the polysaccharide. The GPC has shown that Med1 is a low molecular weight polysaccharide (34.8 kDa) with low PI. The 2D-NMR linkage analysis suggests a diverse array of glycosidic bonds within the exopolysaccharide structure. The functional properties of the EPS were evaluated for food industry applications, specifically for antioxidant (DPPH, FRAP an H2O2). Extracted Med1 EPS revealed significant emulsification activity against different food grade vegetative oils (Coconut oil, Corn oil, Canola oil, Avocado oil, Sunflower oil, Olive oil, and Sesame oil). The highest 33.9% flocculation activity was observed with 60 mg L−1 EPS concentration. It showed water-holding (WHC) of 107.6% and oil-holding (OHC) capacity of 110.8%. The functional EPS produced by Pseudomonas alcaligenes Med1 from Central Andean Chilean hot spring of central Chile can be a useful additive for the food-processing industry.

Isolation, Identification and Pigment Analysis of Novel Cyanobacterial Strains from Thermal Springs.

Cyanobacterial pigments have attracted considerable attention in industry due to their bioactive potential and natural origin. In the present study, the growth dynamics and pigment composition, in terms of chlorophyll a, total carotenoids and phycobiliprotein content, of four cyanobacterial strains isolated from thermal springs, namely Oscillatoria subbrevis CZS 2201, Phormidium ambiguum CZS 2205, Nostoc calcicola TSZ 2203, and Synechococcus sp. CZS 2204, were investigated. The analysis revealed that the maximum quantity of chlorophyll a and total carotenoids was observed in Oscillatoria subbrevis CZS 2201 (26.49 and 3.44 µg mL-1), followed by Phormidium ambiguum CZS 2205 (18.64 and 2.32 µg mL-1), whereas a minimum amount was detected in Synechococcus sp. CZS 2204 (12.13 and 1.24 µg mL-1), respectively. In addition, Oscillatoria subbrevis CZS 2201 showed higher quantity of phycobiliproteins, especially C-phycocyanin (45.81 mg g-1), C-phycoerythrin (64.17 mg g-1) and C-allophycocyanin (27.45 mg g-1). Moreover, carotenoid derivatives of Oscillatoria subbrevis CZS 2201 were also identified, among which β-carotene was the dominant form (1.94 µg mL-1), while the accumulation of zeaxanthin and myxoxanthophyll was relatively high (0.53 and 0.41 µg mL-1, respectively) compared with echinenone and cryptoxanthin (0.34 and 0.23 µg mL-1, respectively). The study revealed that Oscillatoria subbrevis CZS 2201 was a potent producer of secondary carotenoids, including myxoxanthophyll.

Dual-phase Cs4PbBr6/CsPbBr3 perovskite quantum dot borosilicate glass for WLED applications

Owing to inherent structural instability of perovskite quantum dots, they are instability in humid environments and high temperatures conditions. To address this issue, a simple, environmentally friendly glass encapsulated technology is used to protect the perovskite quantum dots. Meanwhile, the dual-phase perovskite structure realized by phase transition engineering can further increase the stability of perovskite quantum dots. In this study, 3D CsPbBr3/0D Cs4PbBr6 dual-phase coexisting perovskite quantum dot glass powders were synthesized through melt quenching and subsequent crystallization induction of thermal treatment and water molecule, respectively. Results showed that compared with thermal treatment induction, perovskite QDs glass powders by water molecules induction exhibited a high PLQY of 24.7 % with a central wavelength of 519 nm and displayed excellent environmental stability. By combining green fluorescence from 3D CsPbBr3/0D Cs4PbBr6 QDs glass powders and red fluorescence powders (CaAlSiN3:Eu), a WLED device with an impressive EQE of 20.6 % was created, indicating a promising application potential.

Pre-Roman U-Th datings of an aqueduct near ancient Lebedos (Aegean Region, Türkiye)

In the vicinity of the ancient city of Lebedos, known as one of the twelve Ionian cities, located south of İzmir in W. Anatolia (Türkiye), the NE-SW-trending active Tuzla Fault zone is characterized by numerous hot springs and associated travertine-type carbonate deposits (sinter). Among these, the active Doğanbey bath features an approximately 560 m-long hot water aqueduct, called the “Roman Aqueduct”. This structure is distinct from the well-known Roman (Byzantine) ruins (Karakoç bath) in the area in terms of its materials and construction techniques. Despite the absence of detailed archaeological or geochronological studies in this region, the Doğanbey bath and aqueduct have conventionally been attributed to the Roman era.The trough and sidewalls of the Doğanbey aqueduct are covered with a 5–25 cm-thick, laminated sinter crust, formed by the flow of hot water. Each sinter lamina comprises radial structures of calcite and/or aragonite, resembling feather-like shrub structures. This study employs the U-Th chronometry to determine the age of sinter layers covering the Doğanbey bath aqueduct. Two layers from a single sinter sample of the ancient Doğanbey aqueduct yielded U-Th ages of 2717 ± 106 and 2528 ± 106 years (BP). These dates indicate a pre-Roman phase of settlement in the Lebedos area, a finding documented for the first time through this study.

Origin of Helium and Associated Fluid in Fault‐Related Hydrothermal Systems of the Eastern Pyrenees

ABSTRACTIntense hydrothermal activity hosted by regional tectonic structures occurs in the Eastern part of the Pyrenees. Helium isotope ratios (3He/4He) in hot springs along the Têt (0.033–0.099 Ra) and the Tech (0.171–0.375 Ra) faults indicate different signatures from purely crustal to slightly contaminated by magmatic helium. 3He/4He ratio increased towards the East, consistently with the observed thinning of the continental crust. These results suggest localised and not interconnected hydrothermal systems at fault scale. The origin of magmatic helium contamination is discussed in the light of the Gulf of Lion geodynamic evolution and data from comparable orogenic hydrothermal systems in the Alps.

The role of gas emissions (He, Rn, and CO2) from fault zones in understanding fault and seismic activity

Active fault zones are critical pathways for the migration of deep fluids to the Earth’s surface, carrying gases such as He, Rn, and CO2 that provide evidence for the physical and chemical dynamics of the Earth’s interior. This review examines the geochemical characteristics of fault zone gases and their implications for understanding fault activity and seismic events. Fault zones with high activity levels exhibit significant gas release, and variations in soil and hot spring gas concentrations can serve as indicators of seismic activity. Changes in gas concentrations and isotopic ratios, particularly before and after earthquakes, reflect the dynamic interplay between deep-sourced and shallow-sourced fluids. Seismic-induced stress alterations enhance gas release along fault zones, leading to observable anomalies that can aid in earthquake monitoring and prediction. The study underscores the importance of isotope tracing in deciphering fluid sources, migration pathways, and the evolution of fault zones, providing valuable information for assessing tectonic activity and mitigating seismic risks.

Theoretical Dimensions of Classification and Segmentation in Therapeutic Wellness Tourism

The article explores the rapidly growing field of wellness tourism, emphasizing the segmentation and classification of therapeutic tourism. It identifies four main types: healing tourism, wellness tourism, spa tourism, and spiritual tourism, all of which contribute significantly to this sector. The knowledge gap lies in the need for a more comprehensive framework for classifying wellness tourism segments and understanding the different health, economic, and cultural implications. The study employs a multi-dimensional analysis that includes therapeutic services, socio-demographic factors, and geographical locations. Findings indicate that hydrotherapy, balneotherapy, and spiritual tourism play a central role in promoting health and wellness, with distinct implications across different regions and tourist profiles. The results underscore the importance of utilizing natural resources like thermal springs for both recreational and medical purposes, emphasizing their historical and current relevance in tourism. The implication of this research suggests that categorizing wellness tourism can aid in targeted marketing strategies, enhance tourist satisfaction, and support the sustainable development of wellness tourism hubs globally.

Lithium enrichment in high-enthalpy geothermal system influenced by seawater, Indonesia

Lithium holds significant importance in energy storage and can be extracted from geothermal water, making it an additional resource to traditional mining. Combining lithium extraction from geothermal water with electricity generation from geothermal energy offers a compelling strategy to address future energy challenges. Situated in Southeast Sumatra, Indonesia, Way Ratai has considerable geothermal potential and is known for its hot springs. This study primarily aims to characterize lithium enrichment within the Way Ratai geothermal system. Water samples from various sources (one spring, seven hot springs, one well, and seawater) were analyzed for cations, anions, trace elements, and isotopic composition. The results show that Way Ratai is an old geothermal system with sodium-chloride water, where lithium enrichment is attributed to interactions between water and rocks, with some influence from seawater. The discrepancy between calculated and observed magnesium (Mg) concentrations suggests a pre-heating mixing process between rainwater and seawater. The reservoir rock in Way Ratai is mostly andesitic, with temperatures ranging from 182o to 227oC. This study enhances our understanding of thermal water characteristics, reservoir temperatures, and water origins in high enthalpy geothermal systems, offering valuable insights into lithium enrichment in coastal geothermal regions.

Financing mode decision of characteristic tourist town based on improved G1 and Z-number-TOPSIS: the Chinese case

PurposeThe objective is to address financing challenges with an innovative technical approach and provide financial support to facilitate the sustainable development of characteristic tourist towns.Design/methodology/approachIn this study, a novel decision model is proposed, which utilizes the CRITIC improved G1 weighting method to analyze financing factors and applies GRA to enhance the TOPSIS model under a Z-Number fuzzy environment. Finally, sensitivity analysis and comparative assessment were conducted to validate the findings and the model.FindingsThe findings indicate that equity financing is the optimal mode of financing for characteristic tourist towns, with bond financing serving as a viable alternative. Key factors influencing financing include economic benefit, social benefit and policy risk. Managers should carefully consider these factors when selecting financing methods in order to enhance efficiency and mitigate risks.Originality/valueAs a new business model and value creation method of cultural and tourism integration, the financing decision of a characteristic tourism town has always been the key to the overall promotion and operation. The research constructs a financing index system for characteristic tourism towns based on benefit and risk considerations, using the hot spring town in Anhui Province, China, as a case study to evaluate eight financing models.

Activity History of the Gangga Graben in the Southern Segment of Kung Co Rift in Southern Tibet Constrained by ESR and U‐Series Dating

ABSTRACTCharacterising the spatial and temporal distribution of the S‐N‐trending rift in southern Tibet is crucial for elucidating the dynamics of E‐W extension within the Tibetan Plateau since the Miocene. The Kung Co–Tangra Yumco rift, located in the central part of the rift system, was initiated at the peak of rifting development. While the initiation of rifting has been ascertained through low‐temperature thermochronology, direct timing constraints remain absent for the Gangga Graben in the southernmost region. Utilising the quartz electron spin resonance (ESR) dating technique, we ascertained the onset age of the eastern boundary fault of the Gangga Graben to be 12.00 ± 1.80 Ma, with an accelerated activity phase at 9.17 ± 1.19 Ma, and an activity age for the western boundary fault at 2.22 ± 0.24 Ma. U‐series dating conducted on the western boundary disclosed a time span of 20–13 ka for hot spring fissure activity. Seismic evidence, inclusive of those from the Gongdapu Horst, indicates persistent activity of the Gangga Graben since the Pleistocene. Comparative analysis of age data from the Kung Co–Tangra Yumco rift suggests that it commenced almost synchronously along its strike at ~14.5–12 Ma. Considering the rifts trending from west to east in southern Tibet and the genetic mechanism of leucogranite, we propose an E‐W extension mechanism in southern Tibet. At ~26–14 Ma, the lithosphere experienced weakened delamination and asthenosphere upwelling, leading to a series of magmatic activities and onset of E‐W extension in southern Tibet. At ~17–7 Ma, as the basal shearing of the underthrusting Indian Plate increased, it marked the peak phase of rifting in southern Tibet.

Understanding freshwater to marine transitional scale growth in Atlantic salmon (Salmo salar)

Abstract The first marine circulus is the scale feature associated with marine entry and has been used to support research evaluating the relationships between size, growth, and survival for Atlantic salmon. Ambiguity in growth rates and circulus deposition during the transition from freshwater to the marine environment leads to difficulty in the correct identification of the first marine circulus. In this study, scale growth occurring after the last freshwater annulus (plus-growth) was characterized for Atlantic salmon smolts migrating out of the Narraguagus River in Maine. Plus-growth was present in over 95% of scales from smolts leaving the river and represented on average 12.2% of total freshwater growth. These findings suggest plus-growth presents a significant source of error in growth analyses, if ignored, and the characterization of this scale feature helps to inform accurate identification of marine entry for future studies. Run day was a driver of plus-growth, suggesting extended freshwater residency provides opportunity for growth prior to smolt emigration. The negative association between fork length and plus-growth suggests smaller smolts that delay migration are demonstrating compensatory growth. Cumulative air temperature was positively associated with plus-growth, suggesting warming spring temperatures driven by climate change may influence size at marine entry for smolts.

Water mites of a high-altitude thermal spring in the Chilean Andes (Acari: Hydrachnidia), with the description of a new Thermacarus species (Acari: Hydrachnidia: Thermacaridae)

New data are presented of water mites from a thermal spring in the high Andes of Chile. Three species have been found, i.e. Thermacarus chilensis n. sp., Hydryphantes thermalis Cook and Wandesia chechoi Cook.