Whole Genome Sequencing Assembly and Annotation of Halobacillus Trueperi S61 Isolated From the Qarhan Salt Lake

Background: Halophilic microbial as prospective resources of biotechnology due to the advantages of flexible survivability. Qarhan Salt Lake is the second largest Salt Lake in the world which contains rich-unique extremophiles and deserved in-depth exploration. Results: Present study first time isolated novel strain Halobacillus trueperi S61 from Qarhan Salt Lake and performed whole-genome sequencing through combined third-generation PacBio and second-generation Illumina technology. The whole genome of Halobacillus trueperi S61 identified 57549 total reads and consists a complete circular chromosome of 4047887 bp with 43.86% GC content without gaps. Total number of 139 non-coding RNA (included 86 tRNA, 30 rRNA and 23 sRNA), 16 gene islands with 260275 bp and two prophages (with 82682 length) were predicted. In addition, the whole genome of Halobacillus trueperi S61 summarized basic annotation for 3982 protein-coding genes, 3980, 3667, 2998 and 2303 unigenes were annotated with Nr, Swissport, KOG and KEGG database. Combined with advanced analysis, 561 carbohydrate enzymes and 4416 pathogen host interactions related genes were identified. The protein function of Halobacillus trueperi S61 was mainly focus on biological processes, and the protein function was mainly distributed in gene transcription and amino acids, and carbohydrates metabolism. Conclusions: The complete whole genome sequence assembly and annotation of novel strain Halobacillus trueperi S61 isolated from Qarhan Salt Lake mainly focus on protein biological processes and antibiotic resistance, provides a potential resource for biotechnology.

Halogenases of Qarhan Salt Lake in the Qaidam Basin: Evidence From Halite Fluid Inclusions

The fluid inclusion composition of halite can help track chemical composition of ancient fluids and, thus, serves as a reliable index to analyze ancient brine in salt lakes. Qarhan Salt Lake (QSL) is the largest potash brine deposit in China. Although the mixing of modern river water and Ca-Cl deep water is widely accepted as potassium formation, the mixing characteristics in the time domain and driving factors of deep water are still unclear. Here, the chemical composition of fluid inclusions in primary halite samples collected from the ISL1A borehole in QSL was measured by LA-ICP-MS technology. The analysis results show that, during the formation stage of the S4 salt layer in QSL, the main potassium salt layer, the contents of Ca2+ and Sr2+ in brine increased significantly. There is evidence confirming that Ca-Cl deep water is beneficial to the enrichment of potassium and the surrounding rivers generally develop terraces. It suggests that, during the formation stage of the QSL potassium salt layer, more Ca-Cl inflow water of the northern margin supplies the salt lake, inferring that it was driven by tectonic activities. In addition, the chemical composition of halite fluid inclusions shows that there is an anomaly in geochemistry at the early stage of salt formation in QSL. By combining the time of tectonic activities, it is inferred that the anomaly is not caused by tectonic activities but maybe caused by a salt-forming event. This work indicates that deep water and tectonic movement have a huge impact on the evolution of salt lakes. Therefore, it is necessary to consider the influence of deep water and tectonic activities on the salt-forming evolution stage of salt lakes when studying the salt-forming evolution stage of salt lakes and paleoclimate by using salt lake deposition.

Simulation study on the mining conditions of dissolution of low grade solid potash ore in Qarhan Salt Lake

The output and grade of liquid potash minerals in Qarhan Salt Lake are decreasing year by year, which has become the main problem restricting the sustainable production of potassium fertilizer. The exploitation and utilization of low-grade solid potash ore, which is in the strata of the Qarhan Salt Lake, represents the fundamental framework for the sustainable development of Qarhan Salt Lake’s potash fertilizer. PHREEQC is a simulation software for hydrogeochemistry. In this paper, PHREEQC was applied to simulate temperature, pH value and solvent chemical characteristics which affect the dissolution process of low-grade solid potash minerals. The simulation results indicate that the optimum temperature for ore dissolution is around 25 °C, because, around this temperature, the dissolving ability of solvents to low-grade solid potash minerals is enhanced, while the dissolving ability to halite remains basically unchanged, which is conducive to selective dissolution of low-grade solid potash. It is recommended the temperature is between 20 and 30 ℃. The simulation results show that, when the pH value of solvents is more than 9, although it is advantageous to selective dissolution of low-grade solid potash minerals, the solvent becomes strong alkali solution, which will cause environmental pollution and seriously corrode materials and equipment in actual production, so it is recommended the pH value of the solvent is adjusted between 6 and 8. The simulation results show that, when the values of K+, Na+, Mg2+, Ca2+, Cl− and SO42− in the solvent are 0.1%, 2.9%, 3.77%, 0.05%, 15.72% and 0.13% respectively, the solubility of low-grade solid potash ores is stronger, which is more conducive to selective ore dissolution. It is suggested that in actual production, the chemical composition of solvents prepared with old brine and fresh water should be as close as possible to the above chemical composition characteristics.

Saline-Soil Deformation Extraction Based on an Improved Time-Series InSAR Approach

Significant seasonal fluctuations could occur in the regional scattering characteristics and surface deformation of saline soil, and cause decorrelation, which limits the application of the conventional time-series InSAR (TS-InSAR). For extending the saline-soil deformation monitoring capability, this paper presents an improved TS-InSAR approach, based on the interferometric coherence statistics and high-coherence interferogram refinement. By constructing a network of the refined interferograms, high-accuracy ground deformation can be extracted through the weighted least square estimation and the coherent target refinement. To extract the high-accuracy deformation of a representative saline soil area in the Qarhan Salt Lake, 119 C-band Sentinel-1A images collected between May 2015 and May 2020 are selected as the data source. Subsequently, 845 refined interferograms are selected from all possible interferograms to conduct the network inversion, based on the related thresholds (the temporal baseline <49 days, the average spatial coherences >0.5, respectively). Compared with the conventional TS-InSAR measurements, both the accuracy and reliability of the extracted deformation results of the saline soil increased dramatically. Furthermore, the testing results indicate that the improved TS-InSAR method has advantages on the deformation extraction in the saline soil region, and is adaptive to reflecting the typical seasonal variations of the saline soil.

The Source, Distribution, and Sedimentary Pattern of K-Rich Brines in the Qaidam Basin, Western China

Potash plays an important role in agricultural production. The Qaidam Basin (QB) in western China is a typical inland evaporite basin, which contains an abundance of K-rich brines, including shallow brines (i.e., surface brines and intercrystalline brines) in salt lakes and deep brines (i.e., pore brines and oilfield brines) in the strata. Significant studies on these brines have been reported; however, the integrated studies on sources of K, its distribution, and the sedimentary pattern of the two brine types are still inadequate. In this study, the K+ concentrations of sixty-four intercrystalline brines from the Qarhan Salt Lake (QSL), the largest playa in the QB, are presented. After combining those results with the major ionic compositions of river waters and deep K-rich brines, and the K+ concentrations of shallow brines in the QB, we concluded that: (1) The K of brines in the QSL is mainly from the high–flux K input by rivers which gain K from silicate weathering, while the “ancient Qaidam Lake” contributed little K to the QSL; (2) the large K flux supplied by rivers, the appropriate concentration degree, and the mixing of river waters and spring waters, cooperatively account for the highest K concentrations of brines in the QSL in the QB. The different river K recharges in different sections and isolated depressions are responsible for uneven K+ concentrations of brines in the QSL. (3) The deep brines are mainly distributed in the western QB. The K source of pore brines is from the interaction of pore water with the overlying evaporite layer. While the K in oilfield brines may be meteoric water, salt dissolution, the mixing of hydrothermal fluids, and the conversion of clay minerals to K-feldspar may consume K in the oilfield brines.

Distribution, Source Identification, and Assessment of Potentially Toxic Elements in the Sediment Core from the Estuarine Region of the Golmud River to the Qarhan Salt Lake, Qinghai, China

The Qarhan Salt Lake has attracted increasing attention due to its significant national economic status and increased human activity, especially mining. Therefore, a sediment core collected from the confluence of the Golmud River to the Qarhan Salt Lake was chosen to investigate the concentrations, pollution levels, and ecological assessment of nine targeted elements (Al, As, Cd, Cr, Cu, Ni, P, Pb, and Zn). The excess 210Pb activities were calculated and a sedimentation rate of approximately 0.041 cm/y was estimated. Elements sources were identified, and the results show that Al, As, Cu, Ni, Pb, and Zn were mainly from natural sources, Cd and P were mainly from human input, and Cr appeared to have both sources. For Cd and P there was an increasing trend from 1987 and 1975, respectively, coinciding with the Chinese economic reform, Qarhan Salt Lake development and utilization, and also with the gross domestic product of Haixi State, Qinghai Province. Though the pollution and ecological assessment showed that there was nil to very low contamination and ecological risk, which is different from previous assumptions, the obviously increasing trend of Cd and P in the surface is still a concern. More attention should be paid to Cd and P in the further development of the Qarhan Salt Lake and the Golmud City.