Search

Copyright of Nonferrous Metals (Extractive Metallurgy) is the property of Beijing Research Institute of Mining & Metallurgy Technology Group and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Salt lakes are a rich source of metals used in various fields. Rubidium is found in small amounts in salt lakes, but extraction technology on an industrial scale has not been developed completely. Clathrate hydrates are crystalline compounds formed by the encapsulation of guest molecules in cage-like structures made of water molecules. One of the most important properties for engineering practices of hydrate-based technologies is the comprehension of the phase equilibrium conditions. Phase equilibrium conditions of CO2 hydrate in rubidium chloride aqueous solution with mass fractions of 0.05, 0.10, 0.15 and 0.20 were experimentally investigated in the pressure range from 1.27 MPa to 3.53 MPa, and the temperature was from 268.7 K to 280.6 K. The measured equilibrium temperature in this study decreased roughly in proportion to the concentration of the RbCl solution from the pure water system. This depression is due to the lowering of the chemical potential of water in the liquid phase by the dissolution of RbCl. Experimental results compared with other salt solution + CO2 hydrate systems showed that the equilibrium temperatures decreased to a similar degree for similar mole fractions. [ABSTRACT FROM AUTHOR]

Membranes facilitate scalable and continuous lithium concentration from hypersaline salt lakes and battery leachates. Conventional nanofiltration (NF) membranes, however, exhibit poor monovalent selectivity in high‐salinity environments due to weakened exclusion mechanisms. This study examines polyamide NF membranes coated with polyelectrolytes enriched with ammonium groups to maintain high monovalent cation selectivity in hypersaline conditions. Over 8000 ion rejection measurements are recorded using salt lake brines and battery leachates. The experiments exemplify the coated membrane's ability to reduce magnesium concentrations to 0.14% from salt lakes and elevate lithium purity to 98% from battery leachates, in a single filtration stage. The membrane's selectivity is retained after 12 weeks in acidic conditions. Molecular dynamics analyses reveal that the ammonium groups create an electrostatic barrier at low pH, selectively hindering multivalent cation transport. This is corroborated by the Coulombic attraction between cations and carboxylate groups, along with a repulsive barrier from ammonium groups. Despite a 14.7% increase in specific energy, a two‐stage NF system using the coated membranes for lithium recovery significantly reduces permeate magnesium composition to 0.031% from Chilean salt lake brines. For NMC leachates, the coated membranes achieve permeate lithium purity exceeding 99.5%, yielding enhanced permeate quality with minor increases in energy demands. [ABSTRACT FROM AUTHOR]

The salt lakes in arid deserts serve as crucial ecological resources and tourist attractions. However, due to the limitations of aeolian sand cover, it is challenging to directly investigate the underground contact relationship between lake water and groundwater. In the Badain Jaran Desert (BJD) of China, the fresh groundwater near salt lakes is the sole source of drinking water. Consequently, a pressing concern arises regarding how groundwater exploitation impacts the intrusion of salt water into groundwater. In this study, Lake Cherigele (CRG) was chosen as a case to investigate the characteristics and migration mechanisms of the saltwater-freshwater interface using numerical simulation methods. The results reveal that: (1) The saltwater-freshwater mixing zone exhibits a wedge-shaped morphology, with a length of 250 to 290 m and a depth ranging from 50 to 70 m within the model. (2) The hydrodynamic conductivity coefficient (K) of the sand layer and molecular diffusion coefficient (Dm) in the desert are identified as the primary parameters influencing the characteristics of the interface. (3) The annual fluctuations in the current groundwater level have a limited impact on the saltwater-freshwater interface; however, excessive groundwater exploitation can lead to the intrusion of salt water into freshwater body. (4) The density difference between groundwater and lake water results in the concentration of groundwater flow lines around the lake, giving rise to the numerous springs observed in the field. [ABSTRACT FROM AUTHOR]

In recent years, with the rapid development of new energy vehicles and energy storage batteries, the consumption of lithium products is increasing, the development and utilization of lithium resources has received a high degree of attention. The currently industrialized lithium extraction method has a long production cycle, low lithium recovery rate, and a slow growth in lithium production, which is difficult to meet the needs of China's new energy industry development. Direct extraction of lithium from low-lithium brine can realize the efficient utilization of low-grade lithium resources, which is of great significance for improving the supply of strategic lithium resources in China. Based on the characteristics of brine resources, this paper summarizes the adsorption, membrane separation, solvent extraction and others methods, which applicable to the extraction of lithium from low lithium concentration and high magnesium lithium ratio of raw brine. The characteristics and effects of various lithium extraction methods were analyzed. The development trend of extracting lithium from brine with low lithium concentration and high magnesium lithium ratio is expected. [ABSTRACT FROM AUTHOR]

Copyright of Jiaoyu Kexue Wenxian is the property of Educational Science Literature (Chinese) Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The availability of lithium resources is of great significance for the development of modern technologies, as well as for civil and military industries. The Qinghai-Tibet Plateau is a region known for its abundance of lithium-rich salt lakes. However, the specific origin of lithium in these lakes is still unknown, which hinders the advancement of the lithium resource business in this region. To research this issue, this study involved the collection of 20 samples from Lakkor Co Salt Lake on Qinghai-Tibet Plateau, encompassing samples of surface brine, cold springs, fresh lakes, and recharge rivers. The composition of anions and cations in these samples was determined. Furthermore, the analysis extensively utilized the Piper three-line diagram, Gibbs model, and ion proportion coefficient. The findings of this study indicate that as the moves from the recharge water system to salt lake, there is a transition in water type from strong carbonate to moderate carbonate and weak carbonate, as well as Na sulfate. This research based on a similar source of both lithium and boron, utilized ion correlation analysis and boron isotope study in the Lakkor Co area, and analyzed the source and transporting process of lithium. The main origin of lithium in Lakkor Co is the dissolution of lithium-rich rocks, recharge water systems, and deep hydrothermal fluids. These findings are highly significant in enhancing the foundational data of lithium-rich brine resources in the Qinghai-Tibet Plateau and are beneficial for assessing the future development of such deposits. [ABSTRACT FROM AUTHOR]

In recent years, extensive exploration has contributed to significant advancements in the geological formations of the Kuqa Depression. In particular, the Paleogene Kumugeliemu Formation exhibits the development of expansive bedded evaporites. The combination of red sandstone, red mudstone, and gypsum-salt layers holds immense potential as a reservoir and cap association, thereby offering promising prospects for oil and gas exploration. However, our understanding of the sedimentary system and model governing this formation remains limited, impeding progress in the field of oil and gas exploration. To address this gap, this study delved into a detailed examination of the stratigraphy, depositional system, and model of the Kumugeliemu Formation through the application of core samples, logging data, and seismic analyses. The primary objective of this study was to establish a comprehensive theoretical foundation for future oil and gas exploration efforts targeting the Kumugeliemu Formation. The findings revealed a distinct division of the Kumugeliemu Formation into two 3rd order sequences, each characterized by a lowstand systems tract, transgressive systems tract, and highstand systems tract. Moreover, all systems tracts were further subdivided into 14 parasequence sets. During the depositional period of the Kumugeliemu Formation, alluvial fan, delta, and salt lake deposition systems developed from the periphery to the central region of the Kuqa Depression. The alluvial fan mainly exhibited braided channel sedimentary microfacies, whereas the delta region indicated plain distributary channels, submerged distributary channels, and interdistributary sedimentary microfacies. The salt lake area is characterized by shore-shallow lacustrine mud, beach-bar, salt mud flat, and salt flat sedimentary microfacies. Throughout the deposition of the Kumugeliemu Formation, the climate of the Kuqa Depression oscillated between arid and humid. During arid periods, the depression experienced diminished water body extent, heightened salinity levels, and extensive distribution of salt and salt mud flats within the basin, with alluvial fans and delta deposits primarily confined to the basin margins. Conversely, during the humid period, the depression experienced an expansion in the extent of the water bodies, leading to a decrease in salinity levels. The distribution of salt flat and salt mud flat deposits within the basin diminished, whereas alluvial fan and delta deposits advanced extensively across the basin. The establishment and spatial arrangement of the sedimentary system within the Kumugeliemu Formation were governed by a complex interplay of certain factors, such as the semi-closed paleotectonic pattern, paleoclimatic conditions of both dry and wet alternation, and the salt source supply brought by the transgression of the Paleo-Tethys Ocean. The findings of this study offer not only a valuable reference framework for the prospective exploration of hydrocarbon resources within the Kumugeliemu Formation of the Kuqa Depression but also potential insights into the evolution of similar depressions in other basins. [ABSTRACT FROM AUTHOR]

Australian isolates of Haloquadratum walsbyi, a square-shaped haloarchaeon, often harbor small cryptic plasmids of the pL6-family, approximately 6 kb in size, and five examples have been previously described. These plasmids exhibit a highly conserved gene arrangement and encode replicases similar to those of betapleolipoviruses. To assess their global distribution and recover more examples for analysis, fifteen additional plasmids were reconstructed from the metagenomes of seven hypersaline sites across four countries: Argentina, Australia, Puerto Rico, and Spain. Including the five previously described plasmids, the average plasmid size is 6002 bp, with an average G+C content of 52.5%. The tetramers GGCC and CTAG are either absent or significantly under-represented, except in the two plasmids with the highest %G+C. All plasmids share a similar arrangement of genes organized as outwardly facing replication and ATPase modules, but variations were observed in some core genes, such as F2, and some plasmids had acquired accessory genes. Two plasmids, pCOLO-c1 and pISLA-c6, shared 92.7% nt identity despite originating from Argentina and Spain, respectively. Numerous metagenomic CRISPR spacers matched sequences in the fifteen reconstructed plasmids, indicating frequent invasion of haloarchaea. Spacers could be assigned to haloarchaeal genera by mapping their associated direct repeats (DR), with half of these matching Haloquadratum. Finally, strand-specific metatranscriptome (RNA-seq) data could be used to demonstrate the active transcription of two pL6-family plasmids, including antisense transcripts. [ABSTRACT FROM AUTHOR]

The Tataleng River (TTR), as an important tributary of the Da Qaidam Salt Lake (DQSL) and Xiao Qaidam Salt Lake (XQSL) in the Qaidam Basin (QB), has an exceptionally high B content. However, the solute sources and the provenance of B in the TTR are still unclear, which significantly hinders a deeper understanding of the source–sink processes of the boron deposits in the QB. In this study, water samples were collected from tributaries, mainstreams, mud volcanoes, hot springs, and rainwater in the TTR area. Through hydrochemical analysis, forward modeling, and B isotope geochemistry methods, combined with the previous research results, some findings were obtained. The hydrochemical type of TTR is Ca–Mg–Cl, and the major mechanism of controlling chemical composition is rock weathering. The solute sources in the TTR are mainly from dissolution of evaporites (75.9%), atmospheric precipitation (20.8%), and a minor contribution from carbonates (3.1%) and silicates weathering (0.6%). The higher B content (0.89–4.30 mg/L, mean = 2.13 mg/L) and lower δ11B value (0.79‰–4.71‰, mean = 4.17‰) of the TTR indicate that the B sources are mainly from mixture of mud volcanic waters (56.19–199.98 mg/L, mean = 113.51 mg/L, − 1.26‰–2.22‰, mean = 0.85‰) in the upper reaches, and the deep groundwater near the Indosinian granite in the lower reaches. The significant difference in boron resources between the two lakes may be due to the enrichment of B in the late Pleistocene in the DQSL, which received exceptionally rich soluble B carried by the ancient TTR during an active tectonic period, while the weakening of tectonic activity and the diversion of the ancient TTR resulted in the supply of B with significantly reduced content to the XQSL. These results are helpful for a deeper understanding of the ore-forming mechanisms of the boron deposits in salt lake. [ABSTRACT FROM AUTHOR]

There is limited research on the variations in brine element changes and the factors that influence them during large-scale exploitation. The Xitaijnar Salt Lake in the Qaidam Basin is a large brine lithium deposit. In this study, we investigated the variations in chemical composition and the factors that influence intercrystalline brine at different time periods. Hydrochemistry, mineralogy, and hydrogeochemical simulation methods were employed to understand the brine evolution. Our results indicate that after nearly 20 years of exploitation, the intercrystalline brine still belongs to the magnesium sulfate subtype, with only slight variations in salinity. The concentrations of Na, K, and SO4 showed a slight increase, while the content of Mg and Cl decreased slightly. The concentrations of B and Li exhibited minor fluctuations. The provenance, water level, and hydraulic connection had minimal influence on the chemical composition of the intercrystalline brine. By contrast, the dynamic dissolution and precipitation of sulfate minerals and halite, as well as drastic changes in hydrological conditions (such as floods), were identified as the main factors affecting the chemical composition of brine. With the large-scale extraction of intercrystalline brine, the content of elements in the salt lake showed a decreasing trend. This can be attributed to the fact that intercrystalline brine is formed through long-term evaporation and concentration. Therefore, during the exploitation process, it is crucial to monitor the hydrochemical variations of intercrystalline brine and understand the controlling factors. The results of this study may prove useful for the sustainable development and utilization of salt lake resources worldwide. [ABSTRACT FROM AUTHOR]

Copyright of Acta Geoscientica Sinica is the property of Acta Geoscientica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Geoscientica Sinica is the property of Acta Geoscientica Sinica Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract In the late stage of underground brine mining in salt lakes, the method of injecting fresh water is often used to extract the salt from the brine storage medium. This method of freshwater displacement breaks the original water–rock equilibrium and changes the evolution process of the original underground brine. To explore the mechanism of salt release in saline water-bearing media under conditions of relatively fresh lake water dissolution, this paper analyzes the changes in the chemical parameters of brine from 168 sampling points in the Mahai salt lake in the Qaidam Basin at three stages (before exploitation, during exploitation, and late exploitation) by correlation analysis, ion ratio analysis, and other methods and investigate the variations in porosity and the evolution laws of brine. The results show that the changes in the main ion content and brine mineralization during the exploitation process are small. The changes in Ca2+ content are significant due to the low solubility of calcium minerals, the precipitation of gypsum during the mixing process, and the adsorption of cations by alternating with Ca2+. Primary intergranular pore skeletons are easily corroded to form secondary pores, which increase the geological porosity. Na+ and Cl- are the dominant ions in the brine in the study area, but the concentration of Ca2 + decreased significantly under the influence of mining, by 41.7% in the middle period and 24.5% in the late period. The correlation between Ca2+ and salinity changes significantly in different mining stages, and the reason for the decrease of Ca2+ may be due to the influence of mineral dissolution, mixing, and anion-cation exchange. The porosity of the layer in the study area showed the opposite trend of Ca2+, and the porosity increased first and then decreased. The innovation of this paper lies in analyzing the reasons and mechanisms of the disturbance of artificial dissolution mining on stratum structure by comparing the hydrochemical characteristics and porosity of underground brine storage media in three different mining stages. The research in this paper provides a theoretical basis for the calculation of brine resource reserves and the sustainable development of underground brine in salt lake areas.

ABSTRACTThe combination of low temperatures, oligotrophic conditions, high altitude, and varying salinity in Tibetan Plateau lakes endows them with a wealth of distinctive fungal resources. This study aimed to investigate the diversity of culturable fungi in sediment and water samples collected from six lakes located on the Tibetan Plateau at elevations above 4,500 m. A total of 843 fungal strains were isolated by dilution plate method using four different media. Initial ITS analyses revealed that they belong to 156 species across 83 genera, spanning 50 families, 26 orders, 12 classes, and 6 phyla. Further morphological and multi-locus phylogenetic analyses were conducted, resulting in the formal descriptions of a new genus, Xizangia, and seven new species, including Alternaria xizangensis, Emericellopsis ovoidea, Myceliophthora xizangica, Preussia cylindricalis, Preussia sedimenticola, Pseudeurotium sedimenticola, and Xizangia sedimenticola. This research provides insights into the biodiversity of culturable fungi in the unique and extreme ecosystem, shedding light on the potential discovery of novel species and genera.

The zooplankton community was analysed in two intermittent salt lakes in Serbia – Lake Velika and Lake Mala Rusanda. Samples were collected twice a month during the wet phase between March and May. A total of 15 zooplankton taxa were identified. Crustaceans were more diverse in Lake Mala Rusanda. The communities of both lakes were composed mainly of cosmopolitan, generalist, euryhaline species. Strictly haline species such as Brachionus asplanchnoidis and Arctodiaptomus spinosus were the dominant components of the zooplankton communities in both lakes. Arctodiaptomus spinosus was most abundant in March and April, accounting for up to 50% of all zooplankton specimens found in a sample. The proportion of juvenile stages of A. spinosus was highest in the March and early April samples. The ratio of males to females varied and was likely related to swarming behaviour as part of the species' reproductive strategy. [ABSTRACT FROM AUTHOR]

Potash, also known as potassium (K), is a crucial component of the agricultural sector and serve as "the food of food". Historically, the formation of potash deposits has been attributed to the "tectonic-climatic" theory, in which the role of prolonged arid climate is still debating. Consider the minerogenetic time scale, paleoclimatic events may have played an undeniable role in the formation of potash. However, few studies have been conducted on this topic, which may impede theoretical development. The Lop Nur playa of the Tarim Basin, Northwest China, is a typical hinterland salt lake that formed during the combined effect of the collision between the Eurasian Plate and the Indian Plate and the Quaternary climatic background. As a potash metallogenetic area, Lop Nur is the best place to study how paleoclimatic events affect salt mineralization. In this study, we summarize the development of paleoclimate records and multiple ages from Quaternary sediments and analyze the mineralization theory of the Lop Nur salt lake. The comprehensive chronicle framework employed in paleoenvironmental reconstruction has unveiled the fluctuating aridity and the subsequent process of playa formation. By integrating mineralization mechanisms, ranging from the "mountain-basin transfer" theory to the "tectonic-climatic-source coupled" theory, we systematically reviewed the potential impacts of paleoclimatic events as both impetuses and limitations in the formation of potash deposits in Lop Nur. From a more prospective aspect of this review, the paleoclimatic events for potash mineralization are examined in relation to the worldwide distribution of salt lakes. This examination takes into account the lacustrine paleo-proxies and potash types, which indicate similar paleoclimatic influences on the mineralization process, albeit with varying origins. In the future, a more comprehensive understanding of potassium salt resources can be achieved through a thorough comparison of reconstructed paleoenvironments and high-resolution regional mineralization modeling results. [ABSTRACT FROM AUTHOR]

In the late stage of underground brine mining in salt lakes, the method of injecting fresh water is often used to extract the salt from the brine storage medium. This method of freshwater displacement breaks the original water–rock equilibrium and changes the evolution process of the original underground brine. To explore the mechanism of salt release in saline water-bearing media under conditions of relatively fresh lake water dissolution, this paper analyzes the changes in the chemical parameters of brine from 168 sampling points in the Mahai salt lake in the Qaidam Basin at three stages (before exploitation, during exploitation, and late exploitation) by correlation analysis, ion ratio analysis, and other methods and investigate the variations in porosity and the evolution laws of brine. The results show that the changes in the main ion content and brine mineralization during the exploitation process are small. The changes in Ca2+ content are significant due to the low solubility of calcium minerals, the precipitation of gypsum during the mixing process, and the adsorption of cations by alternating with Ca2+. Primary intergranular pore skeletons are easily corroded to form secondary pores, which increase the geological porosity. Na+ and Cl- are the dominant ions in the brine in the study area, but the concentration of Ca2 + decreased significantly under the influence of mining, by 41.7% in the middle period and 24.5% in the late period. The correlation between Ca2+ and salinity changes significantly in different mining stages, and the reason for the decrease of Ca2+ may be due to the influence of mineral dissolution, mixing, and anion-cation exchange. The porosity of the layer in the study area showed the opposite trend of Ca2+, and the porosity increased first and then decreased. The innovation of this paper lies in analyzing the reasons and mechanisms of the disturbance of artificial dissolution mining on stratum structure by comparing the hydrochemical characteristics and porosity of underground brine storage media in three different mining stages. The research in this paper provides a theoretical basis for the calculation of brine resource reserves and the sustainable development of underground brine in salt lake areas. [ABSTRACT FROM AUTHOR]

There is a great scientific curiosity to discover all environments sheltering microalgae, especially those with exceptional characteristics from coldest to hottest ones, the purpose remains to explore the potential of the native microalgae flora and the research for new bioactive compounds. This study aimed to isolate a polysaccharide-producing microalga from an extreme ecosystem and to evaluate its capacity to inhibit the α-d-glucosidase enzyme. Chlorella strain is isolated from hypersaline Lake in the Algerian desert. The exopolysaccharide extraction was performed by the concentration of free-cell supernatant in a rotary evaporator. The infrared analysis showed a characteristic footprint of carbohydrates with particular functional groups, such as sulfate. Gas chromatography–mass spectrometry has revealed a hetero-exopolysaccharide composed of galactose 35.75%, glucose 21.13%, xylose 16.81%, fructose 6.96%, arabinose 5.10%, and glucuronic acid 2.68%. The evaluation of the anti-hyperglycemic activity demonstrated a significant α-d-glucosidase inhibition of 80.94 ± 0.01% at 10 mg mL−1 with IC50 equal to 4.31 ± 0.20 mg mL−1. This study opens a vast prospect to use exopolysaccharides as natural nutraceutical or food additive. [ABSTRACT FROM AUTHOR]

The genera Haloarcula and Halomicroarcula are the most closely related genera within the family Haloarculaceae (class Halobacteria). The respective 16S rRNA genes of type strains from the genus Haloarcula showed 94.7–96.5% similarities to their homologous genes of type strains from the genus Halomicroarcula. The Haloarcula species showed 89.3–92.8% rpoB′ gene similarities to Halomicroarcula species. These similarities were higher than the proposed genus boundary. Phylogenomic analysis revealed that these two genera formed a tight cluster separated from Halomicrobium with high bootstrap confidence. The average amino acid identity (AAI) values among Haloarcula and Halomicroarcula were 70.1–74.5%, higher than the cutoff value (67.0%) to differentiate the genera Haloarcula and Halomicroarcula from Halomicrobium. These results indicated that the genus Halomicroarcula should be merged with Haloarcula. Then, six novel species are described based on strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T isolated from coarse sea salt, marine solar saltern, and salt lake (China). These six strains formed separate clades (90.1–99.3% 16S rRNA and 89.0–94.9% rpoB′ gene similarities) and then clustered with current Haloarcula and Halomicroarcula species (89.4–99.1% 16S rRNA and 87.6–95.0% rpoB′ gene similarities), as revealed by phylogenetic analyses. The average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH), and AAI values among these six strains and current Haloarcula and Halomicroarcula species were 76.2–89.8%, 25.3–46.0%, and 70.3–89.7%, respectively, clearly below the species demarcation threshold. These six strains were distinguished from current Haloarcula and Halomicroarcula species according to differential phenotypic characteristics. Six novel species, Haloarculahalophila sp. nov., Haloarculalitorea sp. nov., Haloarcularara sp. nov., Haloarculahalobia sp. nov., Haloarculapelagica sp. nov., and Haloarculaordinaria sp. nov., are proposed to accommodate strains DFY41T, GDY20T, SHR3T, XH51T, YJ-61-ST, and ZS-22-S1T, respectively. [ABSTRACT FROM AUTHOR]

Depending on the season, the primary production of planktonic communities determined by radiotracer analysis varied within a broad range, from 6 to 314 µg C/(L h). Primary production in cyanobacterial mats was 4.2‒10.9 × 103 µg C/(dm3 h), and Chl a content varied from 6‒13 to 132‒140 mg Chl a/m2. For the plankton, the highest values were revealed in summer (25‒46 mg Chl a/m3), with the maximum in August (223 mg Chl a/m3). High abundance of bacterioplankton (0.3‒7.4 × 106 cells/mL) and massive growth of diatoms (0.15 × 106 cells/mL) with predominance of the genus Chaetoceros were found. Sulfate reduction rates varied from 0.037 µmol S/(dm3 h) in the upper reach to 61.87 µmol S/(dm3 h) in the river mouth. [ABSTRACT FROM AUTHOR]

In this study, in particular, the relationship between high lithium values and geological environments was examined. To determine this, the geology, structural geology, hydrogeology, and hydrogeochemistry of the area in the north of the Gülşehir-Yeşilöz sub-basin of the Kızılırmak Basin were investigated. For hydrogeological studies, 19 water samples were collected in May and September. Tectonically, this area has a horst-graben structure. The relationships between the water analysis values of the study area and the tectonic areas were investigated. In particular, the lithium content of the waters in the study area was investigated. Hydrogeochemical properties and seasonal changes in water resources were studied in detail, and their relationship with tectonic areas was evaluated. Water analyses were carried out during wet and dry periods to determine temporal hydrogeochemical changes. According to the analysis, the waters in the area are of Ca-HCO3 and Ca-Mg-HCO3 facies. In addition, there are water samples with high lithium content in the study area. IDW and Kernel diagrams of these were prepared. It was found that these high values were influenced by the rocks formed in the ancient sea and saline lake environments. The region with the highest lithium value is in the formations that represent the former salt lake environment. High lithium (Li) values are generally higher in the region within the Kızılırmak graben. Lithium values in this area were determined as 241.3 µg/L, 154.5 µg/L, 155.2 µg/L, 156.8 µg/L, and 155.6 µg/L. [ABSTRACT FROM AUTHOR]

Objective The Qinghai–Tibet Plateau is rich in salt lake resources, known particularly for the concentration of elements such as boron and lithium, forming many distinctive resource-type salt lakes. Compared with ordinary salt lakes, a notable characteristic of resource-type salt lakes is the abundant supply of elements such as boron and lithium. Consequently, these elements' sources and accumulation patterns are key scientific issues for understanding the genesis and mineralization patterns of resource-type salt lakes. Boron and lithium isotopes, characterized by significant mass differences and variations in natural isotope ratios, serve as effective tracers for studying the material sources of boron and lithium in salt lakes. However, the application of boron and lithium isotopes in salt lake systems faces the following three challenges: (1) There is insufficient understanding of how boron and lithium isotopes respond to the fundamental geochemical processes of salt lakes. The salt dissolution process that occurs when supply water flows into lake basins is the main reason for drastic changes in geochemical parameters. Inadequate recognition of salt dissolution processes can lead to an overinterpretation of boron and lithium isotope fractionation changes, weakening their tracking capabilities. (2) Isotope fractionation degree is conflated with changes in isotope composition. In salt lake research, discussions of the solid phase's influence on boron and brine's lithium isotopes are often based solely on fractionation factors between the solid and liquid phases, without considering the ratios of boron and lithium amounts involved in the fractionation process. (3) Discrepancies still exist in understanding the fractionation patterns of boron and lithium isotopes during salt crystallization. Methods In light of these problems, our study systematically reviews and analyzes the mechanisms of boron and lithium isotopic fractionation in salt lake systems and summarizes some essential understandings. Conclusion (1) Only salt crystallizations have specific impacts on B and Li isotopes in salt lakes. Since there is a genetic association between salt assemblages and specific salt lake hydrochemical types, the salt lakes with the same hydrochemical type exhibit consistent patterns of B and Li isotope changes during their evolutionary processes. Until halite precipitation, the B and Li isotopic compositions in sulfate- and chloride-type salt lakes are in accord with δ11B and δ7Li values of their sources instead of being controlled by their salt deposits. In contrast, the paths of B and Li isotopic changes of carbonate-type salt lakes are complex and are divided into two branches: calcite subtype and hydromagnesite subtype. After calcite precipitation, the δ11B value of the salt lake increases, and its δ7Li value is marginally above source characteristics (less than 2‰). After hydromagnesite precipitation, the δ11B value of the salt lake is also marginally above source characteristics (less than 2‰). After the stage of halite precipitation, the B and Li isotopic compositions of salt lakes in all types show an increasing trend. (2) Based on the evolutionary processes of B, Li, and K during seawater evaporation, the amounts of B, Li, and K in the current salt lake represent most of the corresponding resources in the lake if the salt lake never experienced complete dryness such as playa. For the salt-dissolving lake, most of the B, Li, and K resources are preserved in salt deposits and interstitial brine at the bottom of the lake. It is optimal for the resource potential of a carbonate-type salt lake in the salt-dissolving lake. (3) The B sources of the current Damxung Co salt lake located in the Tibetan Plateau are from clay carbonates exposed to the lake shore and highly soluble salts and interstitial brine at the bottom of the lake. The geothermal waters produced during early hydrothermal activity are the original B source of the Damxung Co salt lake. Based on mass balance equations, it is estimated that the B resource at the bottom of the Damxung Co salt lake is at least 9.1×106t (B2O3), and the lithium resource is at least 8.6 ×106t (LiCl).

Copyright of Journal of Geomechanics is the property of Journal of Geomechanics Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In recent years, interest in natural therapeutic mud has been growing all over the world. This natural product has a positive therapeutic effect on the skin and has fewer side effects on the human body. There are more than 40 thousand salt lakes in Kazakhstan. Most of them have natural mud sources, the potential of which has not yet been fully explored. The review presents an analysis of the available information on the physical and chemical properties of the main sources of natural mud from salt lakes in Kazakhstan and Kazakh sanatoriums that use natural mud in the treatment. All available publications, presenting the systematic studies, were used for data analysis. A comparative analysis of the mineralization of water, brine, and silt in one reservoir shows that the mineralization of water is not always the least. The available data indicate a point and partial nature of peloid studies, e.g., inorganic composition of natural muds from Western and Southern Kazakhstan is well described in the literature. In turn, there is a lack of these data from Northern and Eastern Kazakhstan. Studies of peloids in these regions seem to be a promising direction of the future research for both local and world scientists. What is more, there is also a big gap in the analysis of organic matter of muds from the Kazakh lakes. Comparing the state of the art, i.e., the studies from other parts of Asia and Europe, the identification of the organic part of muds is another desirable direction as a potential source of biologically active compounds of natural origin. [ABSTRACT FROM AUTHOR]

In the last decade, North Africa has witnessed significant population growth, particularly those bordering the Mediterranean Sea. This led to increased demand for groundwater, which is an essential source for various water uses such as drinking water supplies and irrigation. Generally, human activities play a crucial role in the different quantitative and qualitative changes in groundwater. Now, climate changes such as a decrease in precipitation have also led to a shortage of water resources and a decline in the groundwater table. This paper presents the impact of climate changes on groundwater resources in the Ain Azel region, Setif, northeastern Algeria. The analysis of long-term spatiotemporal variability in rainfall over 63 years (1958–2021) revealed a significant decline in groundwater recharge, especially after 2013. In contrast, the Pettitt and Mann–Kendall tests show increased temperatures with breaks between 1984 and 1986. A piezometric analysis of the alluvial aquifer demonstrated a significant decline in groundwater levels in the last 20 years. Hydrochemical analysis showed that groundwater in the region is dominated by Ca–Mg–Cl water type, which indicates the presence of water salinity phenomenon. Water Quality Index (WQI) analysis showed the deterioration of groundwater in the area, which may be caused by several factors: brine intrusion from the Salt Lake (Sebkha) in the north; the dissolution of evaporites (Triassic) and/or anthropogenic sources of agricultural and industrial origin. Our findings provide an overview summarizing the state of groundwater, which will help improve groundwater resource management in the region in the coming years. [ABSTRACT FROM AUTHOR]

The bedrock weathered crust in front of the Altun Mountains in the Qaidam Basin, western China, is different from others because this is a salt‐lake basin, where saline water fluid infiltrates and is deposited in the overlying strata. A large amount of gypsum infills the bedrock weathered crust, and this has changed the pore structure. Using core observation, polarized light microscopy, electron probe, physical property analysis and field emission scanning electron microscopy experiments, the characteristics of the weathered bedrock have been studied. There are cracks and a small number of dissolved pores in the interior of the weathered crust. Matrix micropores are widely developed, especially the various matrix cracks formed by tectonics and weathering, as well as the stress characteristics of small dissolved pores, and physical properties such as porosity and permeability. This 'dual structure' developed in the bedrock is important for guiding the exploration of the lake basin bedrock for natural gas. [ABSTRACT FROM AUTHOR]

Displacement prediction of transmission towers is essential for the early warning of transmission network deformation. However, there is still a lack of prediction on the ground subsidence of the tower foundation. In this study, we first used the multi-temporal interferometric synthetic aperture radar (MT-InSAR) approach to acquire time series deformation for the transmission lines in the Salt Lake area. Based on the K-shape clustering method and field investigation results, towers #95 and #151 with representative foundation deformation characteristics were selected for displacement prediction. Combined with field investigations and the characteristics of saline soil in the Salt Lake area, the trigger factors of transmission tower deformation were analyzed. Then, the displacement and trigger factors of the transmission tower were decomposed by variational mode decomposition (VMD), which could closely connect the characteristics of the foundation saline soil with the influence of the trigger factors. To analyze the contribution of each trigger factor, the maximum information coefficient (MIC) was quantified, and the best choice was made. Finally, the hyperparameters of the long short-term memory (LSTM) neural networks were optimized using a convolutional neural network (CNN) and the grey wolf optimizer (GWO). The findings reveal that the refined deep learning models outperform the initial model in generalization potential and prediction precision, with the CNN–LSTM model demonstrating the highest accuracy in predicting the total displacement of tower #151 (RMSE and R2 for the validation set are 0.485 and 0.972, respectively). Given the scant research on the multifactorial influence on the ground subsidence displacement of transmission towers, this study's methodology offers a novel perspective for monitoring and early warning of ground subsidence disasters in transmission networks. [ABSTRACT FROM AUTHOR]

The strategic importance of lithium in global development has become increasingly prominent due to the rapid growth of the new energy automotive industry and the continuous advancements in controllable nuclear fusion technology. Lithium minerals in salt lakes possess advantageous characteristics, such as abundant reserves, environmental sustainability, and economic viability. Furthermore, with ongoing improvements in the lithium extraction process, the availability of lithium minerals in salt lakes is expected to further increase. The Qaidam Basin Salt Lake in China has served as the location for the establishment of numerous lithium carbonate production enterprises, resulting in a lithium carbonate production volume of 7 × 104 t/yr in 2022. How to meet the growing need for lithium resources has become an enterprise focus. Nevertheless, there are large amounts of clay minerals in and around the bottom and periphery of the salt lake in the Qaidam Basin, and whether these minerals are of exploitable value, regardless of the state of the occurrence of lithium resources, remains unexplored. To ascertain the attributes, extent, and distribution of the lithium occurrence within the clayey layer of the Qaidam Basin, as well as to assess its resource potential, a total of 87 drill holes were conducted within a designated area of the Mahai Basin, which is a secondary basin in the Qaidam Basin. The subsequent analysis encompassed the examination of the lithium content within the clay minerals, the mineral composition of the clay, and, ultimately, the evaluation of the resource potential within the region. Compared with Quaternary salt lake deposits, brine deposits in gravel pores, and the Paleogene–Neogene Li-bearing salt deposits that have been studied, it is suggested that this is a novel form of a clay-type sedimentary Li deposit within the Qaidam Basin. The findings of this research will serve as a fundamental basis for future endeavors pertaining to the exploration and exploitation of lithium deposits within salt lake areas. [ABSTRACT FROM AUTHOR]

Copyright of Acta Petrologica et Mineralogica / Yanshi Kuangwuxue Zazhi is the property of Acta Petrologica et Mineralogica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Acta Petrologica et Mineralogica / Yanshi Kuangwuxue Zazhi is the property of Acta Petrologica et Mineralogica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Four halophilic archaea strains, AD-4T, CGA30T, CGA73T, and WLHSJ27T, were isolated from a salt lake and two soda lakes located in different regions of China. The 16S rRNA and rpoB′ gene sequence similarities among strains AD-4T, CGA30T, CGA73T, WLHSJ27T, and the current species of the family Natrialbaceae were 90.9–97.5% and 83.1–91.8%, respectively. The phylogenetic and phylogenomic analyses revealed that these four strains separated from existing genera in the family Natrialbaceae and formed distant branches. The ANI, isDDH, and AAI values among these four strains and the current members of the family Natrialbaceae were 72–79%, 20–25%, and 63–73%, respectively, much lower than the threshold values for species demarcation. Strains AD-4T, CGA73T, and WLHSJ27T may represent three novel genera of the family Natrialbaceae according to the cutoff value of AAI (≤ 76%) proposed to differentiate genera within the family Natrialbaceae. These four strains could be distinguished from the related genera according to differential phenotypic characteristics. The major phospholipids of these four strains were identical while their glycolipid profiles were diverse. DGD-1 is a major glycolipid found in strain AD-4T, trace glycolipids, DGD-1, and S-DGD-1, and (or) S-TGD-1 was found in the other three strains. The major respiratory quinones detected in the four strains were menaquinone MK-8 and MK-8(H2). This polyphasic classification indicated that strains AD-4T, CGA73T, and WLHSJ27T represent three novel species of three new genera with the family Natrialbaceae, and strain CGA30T represents a novel species of Halovivax. [ABSTRACT FROM AUTHOR]

The change in the ecological environment in the arid core area is a critical issue in the context of global warming. To study the paleoclimate evolution, precise identification of minerals deposited in Asia's arid hinterland, Lop Nur Salt Lake, NW China was conducted. The hyperspectral data of the salt crust was sampled to identify the species and content of sedimentary minerals, and the multispectral photos were used to reconstruct the salt crust morphology using the unmanned aerial vehicles platform. The SUnSAL (sparse unmixing by variable splitting and augmented Lagrangian) method was employed to inverse the sedimentary mineral components along the shoreline. The heterogeneity of salt and clay minerals in bright and dark ear-shaped strips was evaluated. The paleoclimatic environment associated with salt lake extinction was reconstructed by analyzing paleoclimate records of sediments, spectral reflectance and morphology of the salt crust. Results show that: (1) the variations in the micro-geomorphology of the salt crust are obviously the reason for the formation of bright and dark ear-shaped strips and the differences in the species and relative content of the sedimentary minerals are the microscopic reason. The high ratio of sedimentary salt minerals to clay minerals (RS/C) contributes to the high reflectivity, and the salt crust presents a bright texture. The low RS/C results in the low reflectivity, salt crust presents a dark texture; (2) the bright and dark ear-shaped strips represent warm-arid and cold-humid climates. The shape of the Lop Nur Lake shoreline evolved due to alternating warm-dry and cold-humid paleoclimate changes. [ABSTRACT FROM AUTHOR]

Copyright of Xinjiang Agricultural Sciences is the property of Xinjiang Agricultural Sciences Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The delta-salt lake system was developed in the sedimentary period of Qianjiang Formation in Qianjiang sag, Among them, many lithologic reservoirs were found in Eq34、Eq 40 and other oil formations in the hollow zone, which has broad exploration potential. This paper analyzes the sedimentary background and reservoir characteristics of Benghu Syncline in Qianjiang sag, and summarizes the reservoir distribution combined with seismic reflection characteristics、attribute analysis、forward modeling and inversion description. Using logging data and seismic data for fine labeling of reservoir, identification and tracking, to predict the favorable sand body distribution area, it is considered that the main controlling factors of reservoir formation in semi-arid period are reservoir and oil source distance, and the prediction results are consistent with drilling and geological laws. [ABSTRACT FROM AUTHOR]

Mar Chiquita is an extensive saline lake associated with the Dulce River marshes, which together form a wetland of about 1,000,000 ha in central Argentina. The lake has undergone marked fluctuations in surface area and salinity in recent decades, which has produced a marked effect on waterbirds. In the last decade, surface area and salinity of Mar Chiquita have changed little. However, there have been important changes in some species of waterbirds, particularly the Chilean Flamingo (Phoenicopterus chilensis) and the Wilson's Phalarope (Phalaropus tricolor). Also remarkable has been the appearance of eight species that inhabit marine coasts in South America, in addition to other seven coastal species previously recorded. In the present decade, Mar Chiquita has dropped 1.7 m, but for the moment this change has not had a major influence on waterbirds. [ABSTRACT FROM AUTHOR]

Simple Summary: A comprehensive geochemical, mineralogical and microbiological analysis of bottom sediments was carried out in five main areas of the littoral zone of Lake Issyk-Kul, one of the largest mountain lakes in the world. The aim of this work is to study the microbial diversity of bottom sediments of Lake Issyk-Kul and to establish the role of microbiota in biogeochemical processes, in particular, its involvement in authigenic mineral formation. Aerobic and anaerobic oxidation of organic matter begins at the water-sediment interface and is the main source of carbon dioxide which provides the formation of carbonate minerals. Oxygen consumption during organic carbon oxidation triggers anaerobic sulphate reduction processes, leading to the formation of authigenic sulphide minerals. This work is the initial stage in the study of the microbiology and biogeochemistry of the ecosystem of Lake Issyk-Kul, and the data obtained will allow a better understanding of the processes of C, N and S cycling in the lake and the mechanisms of formation of modern bottom sediments. This article presents geochemical, mineralogical and microbiological characteristics of five samples of modern bottom sediments in the littoral zone of the high-mountain salty lake Issyk-Kul. The 16S rRNA gene sequencing method shows that the microbial community consists of organic carbon degraders (representatives of phyla: Proteobacteria, Chloroflexi, Bacteroidota and Verrucomicrobiota and families Anaerolineaceae and Hungateiclostridiaceae), photosynthetic microorganisms (representatives of Chloroflexi, phototrophic Acidobacteria, purple sulphur bacteria Chromatiaceae and cyanobacteria) and bacteria of the reducing branches of the sulphur biogeochemical cycle (representatives of Desulfobacterota, Desulfosarcinaceae and Desulfocapsaceae). The participation of microorganisms in processes in the formation of a number of authigenic minerals (calcite, framboidal pyrite, barite and amorphous Si) is established. The high diversity of microbial communities indicates the presence of labile organic components involved in modern biogeochemical processes in sediments. The active destruction of organic matter begins at the water-sediment interface. [ABSTRACT FROM AUTHOR]

Salt fields are indispensable for the salt lake industry, yet their substrates, which are rich in valuable resources accumulated over time by the formation of solid solution enrichment, always stand at a neglected position. In this study, the distribution and occurrence state of elements in the Mahai Salt Lake substrate were comprehensively investigated by multiple characterizations. The substrate was primarily found to consist of calcium-silica‑aluminum minerals, with significant concentrations of lithium (0.0053 %), strontium (0.1130 %), and rubidium (0.0266 %) adsorbed onto these mineralized phases. Besides, an echelon extraction was developed to exploit these valuable resources including hydrochloric acid leaching and segmented calcination-leaching coupled process. It was confirmed that over 95 % of rubidium and 93 % of strontium could be effectively extracted via hydrochloric acid leaching through cation exchange mechanisms. 80 % lithium was extracted by calcination-leaching coupled process with three cycles to conquer the interlayer structure of mineralized lithium, facilitating the occupation of Li+ lattice sites by H+. [Display omitted] • Brine substrate found rich in valuable resources due to long-term accumulation of solid solutions. • Acid leaching and its coupling with calcination were developed for effective extraction of Rb, Sr, and Li. • The extraction mechanism of valuable elements from brine substrate was revealed. [ABSTRACT FROM AUTHOR]

Microbial communities are important components of alpine lakes, especially in extreme environments such as salt lakes. However, few studies have examined the co-occurrence network of microbial communities and various environmental factors in the water of salt lakes on the Qinghai-Tibet Plateau. From May to June 2019, nine samples from seven salt lakes with water salinity ranges from 13 to 267‰ on the Qinghai-Tibet Plateau were collected. There were great differences between low-salinity samples and high-salinity samples in the inorganic salt ion concentration, pH, and biodiversity. In addition, the microbial community sturcture in low-salinity samples and high-salinity samples differed, suggesting that each sample has its own specific species. The co-occurrence network suggests that salinity was the most important forcing factor. We believe that salinity and inorganic salt ions can result in differences in microbial community in different salt lakes. This sequencing survey of multiple salt lakes with various salinities on the Qinghai-Tibet Plateau enhances our understanding of the response of microbial communities to environmental heterogeneity. [ABSTRACT FROM AUTHOR]

In the Crimean Peninsula, there are several hypersaline lakes that have hydromineral and biological resources. However, they are under a significant anthropogenic load, which together with the climate change leads to negative consequences for the ecosystems. The aim of the work was to study the seasonal changes of physicochemical parameters of water (temperature, pH, oxygen content, salinity, redox potential Eh, optical density and transparency) and Artemia population in Saki Lake in 2022. For the daily fluctuations of temperature, O2, CH4 and CO2, a vertical temperature profile measuring system was installed at the boundaries of the air, water and bottom at a depth of 4 m and with a spatial discreteness of 0.2 m. The drive sensors for the content of gases assay in the air were installed. The increase in salinity and Eh in summer was accompanied by an increase in air and water temperature. Simultaneously, decreases in oxygen content and pH in brine have been observed. Artemia cysts were found throughout the year, nauplii were mostly available during spring and autumn, and the adults were shown in summer. The obtained results demonstrated the seasonal fluctuations in the hypersaline ecosystem within the ongoing climate change, and they can be used for the development of the optimal management of the mineral and biological resources of such water bodies. [ABSTRACT FROM AUTHOR]

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The Streptomyces cavourensis strain 2BA6PGT was isolated from sediment from the bottom of the salt lake Verkhnee Beloe (Buryatia, Russia). This strain's 7,651,223 bp complete genome has a high G + C content of 72.1% and consists of 7,069 coding sequences and 315 subsystems. The 16S ribosomal RNA of isolate 2BA6PGT was most closely related to Streptomyces cavourensis strain NBRC 13026T (98.91% identity), followed by Streptomyces bacillaris strain ATCC 15855T (95.36%), Streptomyces rhizosphaericola strain 1AS2cT (94.68%), and Streptomyces pluricolorescens strain JCM 4602T (86.75%). These comparisons were supported by pairwise comparisons using average nucleotide identity (ANI) and DNA-DNA hybridization analysis. This is the first complete genome reported on Streptomyces cavourensis isolated from sediment from the bottom of the salt lake Verkhnee Beloe. The complete genome sequence has been deposited at the NCBI GenBank with an accession number CP101140.

Salt lakes on the Tibetan Plateau (TP) are rich in lithium (Li), boron (B) and other mineral resources, and accurate assessment of the mineral content and spatial distribution of the brine in those salt lakes is important to guide the development and utilization of their mineral resources. There are few studies estimating the mineral content of salt lakes on the TP due to the lack of in situ investigation data. This study introduced an intelligent prediction model combining a feature selection algorithm with a machine learning algorithm using Sentinel-2 satellite data to estimate the Li, B, and TDS contents of Bieruoze Co and Guopu Co lakes on the TP. First, to enrich the spectral information, four mathematical transformations (reciprocal, logarithmic, reciprocal of logarithm, and first-order derivative) were applied to the original bands. Then, feature selection was performed using the genetic algorithm (GA) to select the optimal input variables for the model. Finally, prediction models were constructed by partial least squares regression (PLSR), multiple linear regression (MLR), and random forest (RF). The results showed that: 1) The spectral mathematical transformation provided rich spectral information for the mineral content estimation. 2) The performance of the estimation model constructed by the feature optimization method using GA was better than that of the estimation model constructed based on all spectral bands. Based on GA for feature optimization, the MAPE of GA-RF for estimating Li, B and TDS contents on the testing set was reduced by 77.52%, 28.54% and 36.79%, respectively. 3) Compared with the GA-MLR and GA-PLSR models, GA-RF estimated Li (R2=0.99, RMSE=1.15 mg L-1, MAPE=3.00%), B (R2=0.97, RMSE=10.65 mg L-1, MAPE=2.73%), and TDS (R2=0.93, RMSE=0.60 g L-1, MAPE=1.82%) all obtained the optimal performance. This study showed that the combination of the GA-based feature selection method and the RF model has excellent performance and applicability for monitoring the content of multiple minerals using Sentinel-2 imagery in salt lakes on the TP.

Global warming is inducing dramatic changes in fluvial geomorphology and reshaping the hydrological connections between rivers and lakes. The water level and area of the Salt Lake have increased rapidly since the outburst of the Zonag Lake in the Hoh Xil region of the Qinghai–Tibet Plateau in 2011, threatening the downstream infrastructure. However, fewer studies have focused on its spatiotemporal variation and overflow risk over long time series. Here, we used three machine learning algorithms: Classification and Regression Trees (CART), Random Forest (RF), and Support Vector Machine (SVM) to extract the area of the Salt Lake for a long time series, analyzed its spatiotemporal variation from 1973 to 2021, and finally assessed the overflow risk. The Kappa coefficient (KAPPA) and the overall accuracy (OA) were used to evaluate the performance of the models. The results showed that Random Forest performs superior in lake extraction (KAPPA = 0.98, overall accuracy = 0.99), followed by Classification and Regression Trees and Support Vector Machine. normalized difference water index is the relatively important feature variable in both RF and CART. Before the outburst event, the area change of the Salt Lake was consistent with the variation in precipitation; after that, it showed a remarkable area increase (circa 350%) in all orientations, and the main direction was the southeast. Without the construction of the emergency drainage channel, the simulation result indicated that the earliest and latest times of the Salt Lake overflow event are predicted to occur in 2020 and 2031, respectively. The results of this paper not only demonstrate that RF is more suitable for water extraction and help understand the water system reorganization event.

Six novel halophilic archaeal strains of XZYJT10T, XZYJ18T, XZYJT40T, XZYJT49T, YCN54T and LT46T were isolated from a solar saltern in Tibet, a salt lake in Shanxi, and a saline soil in Xinjiang, China. Sequence similarities of 16S rRNA and rpoB′ genes among strains XZYJT10T, XZYJ18T, XZYJT40T, XZYJT49T, YCN54T, LT46T and current members of Halorussus were 90.6–97.8% and 87.8–96.4%, respectively. The average nucleotide identity and in silico DNA-DNA hybridization values among these six strains and current Halorussus members were in the range of 76.5–87.5% and 21.0–33.8%, respectively. These values were all below the species boundary threshold values. The phylogenomic tree based on 122 conserved archaeal protein marker genes revealed that the six novel strains formed individual distinct branches and clustered tightly with Halorussus members. Several phenotypic characteristics distinguished the six strains from current Halorussus members. Polar lipid analysis showed that the six novel strains contained phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and two to three glycolipids. Phenotypic, chemotaxonomic and phylogenetic properties showed that the six strains represented six novel species within the genus Halorussus, for which the names Halorussusvallis sp. nov., Halorussusaquaticus sp. nov., Halorussusgelatinilyticus sp. nov., Halorussuslimi sp. nov., Halorussussalilacus sp. nov., and Halorussussalinisoli sp. nov. are proposed. [ABSTRACT FROM AUTHOR]