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Rock-ice avalanches have frequently occurred in the Eastern Himalayan Syntaxis region due to climate change and active tectonic movements. These events commonly trigger catastrophic geohazard chains, including debris flows, river blockages, and floods. This study focuses on the Zelongnong Basin, analyzing the geomorphic and dynamic characteristics of high-altitude disasters. The basin exhibits typical vertical zonation, with disaster sources initiating at elevations exceeding 4000 m and runout distances reaching up to 10 km. The disaster chain movement involves complex dynamic effects, including impact disintegration, soil-rock mixture arching, dynamic erosion, and debris deposition, enhancing understanding of the flow behavior and dynamic characteristics of rock-ice avalanches. The presence of ice significantly increases mobility due to lubrication and frictional melting. In the disaster event of September 10, 2020, the maximum flow velocity and thickness reached 40 m/s and 43 m, respectively. Furthermore, continuous deformation of the Zelongnong glacier moraine was observed, with maximum cumulative deformations of 44.68 m in the distance direction and 25.96 m in the azimuth direction from March 25, 2022, to August 25, 2022. In the future, the risk of rock-ice avalanches in the Eastern Himalayan Syntaxis region will remain extremely high, necessitating a focus on early warning and risk mitigation strategies for such basin disasters.

期刊论文 2024-10-01 DOI: 10.1111/1755-6724.15207 ISSN: 1000-9515

Mount Everest provides natural advantages to finding radiation-resistant extremophiles that are functionally mechanistic and possess commercial significance. (1) Background: Two bacterial strains, designated S5-59T and S8-45T, were isolated from moraine samples collected from the north slope of Mount Everest at altitudes of 5700m and 5100m above sea level. (2) Methods: The present study investigated the polyphasic features and genomic characteristics of S5-59(T) and S8-45(T). (3) Results: The major fatty acids and the predominant respiratory menaquinone of S5-59(T) and S8-45(T) were summed as feature 3 (comprising C16:1 omega 6c and/or C16:1 omega 7c) and ubiquinone-10 (Q-10). Phylogenetic analyses based on 16S rRNA sequences and average nucleotide identity values among these two strains and their reference type strains were below the species demarcation thresholds of 98.65% and 95%. Strains S5-59(T) and S8-45(T) harbored great radiation resistance. The genomic analyses showed that DNA damage repair genes, such as mutL, mutS, radA, radC, recF, recN, etc., were present in the S5-59(T) and S8-45(T) strains. Additionally, strain S5-59(T) possessed more genes related to DNA protection proteins. The pan-genome analysis and horizontal gene transfers revealed that strains of Sphingomonas had a consistently homologous genetic evolutionary radiation resistance. Moreover, enzymatic antioxidative proteins also served critical roles in converting ROS into harmless molecules that resulted in resistance to radiation. Further, pigments and carotenoids such as zeaxanthin and alkylresorcinols of the non-enzymatic antioxidative system were also predicted to protect them from radiation. (4) Conclusions: Type strains S5-59(T) (=JCM 35564T =GDMCC 1.3193T) and S8-45(T) (=JCM 34749T =GDMCC 1.2715T) represent two novel species of the genus Sphingomonas with the proposed name Sphingomonas qomolangmaensis sp. nov. and Sphingomonas glaciei sp. nov. The type strains, S5-59(T) and S8-45(T), were assessed in a deeply genomic study of their radiation-resistant mechanisms and this thus resulted in a further understanding of their greater potential application for the development of anti-radiation protective drugs.

期刊论文 2022-07-05 DOI: http://dx.doi.org/10.3390/microorganisms10102037

The study analyzed synthetically spatiotemporal distribution and evolution status of moraine-dammed lakes and potential dangerous glacial lakes (PDGLs) in the Qinghai-Tibetan Plateau (QTP) and revealed integrated risk degree of county-based glacier lake outburst floods (GLOFs) disaster by combining hazard of PDGLs, regional exposure, vulnerability of exposed elements, and adaptability and using the analytic hierarchy process and weighted comprehensive method. The results show there are 654 moraine-dammed lakes (> 0.018 km(2)) with a total area of 200.25 km(2)in the QTP in the 2010s, of which 246 lakes with a total area of 78.38 km(2)are identified as PDGLs. Compared with 1990s, the number of lakes decreased only by 2.22%, whereas total lake area expanded by 25%. All PDGLs area increased by 84.40% and was higher significantly than 4.06% of non-PDGLs. The zones at very high and high integrated risk of GLOF disasters are concentrated on the middle Himalayas, middle-eastern Nyainqentanglha, and southern Tanggula Mountain. On the county scale, Nyalam, Tingri, Dinggye, Lhozhag, Zhongba, Gamba, Kangma of the Himalayas, and Nierong, Dingqing, Banbar, Baqing, Bomi, and Basu of the Nyainqentanglha are located in the very high-risk zone, whereas other areas have low and very low integrated risk. The regionalization results for GLOF disasters risk are consistent with the distribution of historical GLOF disaster sites.

期刊论文 2020-12-01 DOI: http://dx.doi.org/10.1007/s10346-020-01443-1 ISSN: 1612-510X

A bacterial strain, designated S9-5(T), was isolated from moraine samples collected from the north slope of Mount Everest at an altitude of 5500 m above sea level. A polyphasic study confirmed the affiliation of the strain with the genus Sphingomonas. Strain S9-5(T) was an aerobic, Gram-stain-negative, non-spore-forming, non-motile and rod-shaped bacterium that could grow at 10-40 degrees C, pH 5-8 and with 0-9% (w/v) NaCl. Q-10 was its predominant respiratory menaquinone. Diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, an unidentified phospholipid, an unidentified aminophospholipid and eight unidentified lipids comprised the polar lipids of strain S9-5(T). Its major fatty acids were summed feature 8 (C-18:1 omega 7c and/or C-18:1 omega 6c) and C-16:0. The G+C content was 65.75mol%. Phylogenetic analysis based on 16S rRNA sequences showed that strain S9-5(T) was phylogenetically closely related to Sphingomonas panaciterrae DCY91(T) (98.17%), Sphingomonas olei K-1-16(T) (98.11%) and Sphingomonas mucosissima DSM 17494(T) (97.39%). The average nucleotide identity values among strain S9-5(T) and Sphingomonas panaciterrae DCY91(T), Sphingomonas olei K-1-16(T) and Sphingomonas mucosissima DSM 17494(T) were 78.82, 78.87 and 78.29%, respectively. Based on the morphological, physiological and chemotaxonomic data, strain S9-5(T) (=JCM 34750(T)=GDMCC 1.2714(T)) should represent a novel species of the genus Sphingomonas, for which we propose the name Sphingomonas radio-durans sp. nov.

期刊论文 2020-08-01 DOI: http://dx.doi.org/10.1099/ijsem.0.005312 ISSN: 1466-5026

Soils in ice-free areas of Elephant Island (South Shetland Islands) have been forming since the last deglaciation following the glacial retreat that started in the area probably later than 9.7-5.5 ka. In paraglacial landscapes, landforms and processes in transition from glacial to nonglacial conditions are experiencing rapid environmental adjustments under conditions of climate change. Soils are highly sensitive and can be good descriptors of these transitional changes. A soil sampling campaign was undertaken for characterizing soils developed on moraines and marine platforms, underlain by metamorphic rocks and with distinctive periglacial features. Eight soil profiles were sampled to investigate the processes involved in their development and the relations with main landforms and processes of ice retreat. The stony Cryosols with mosses and lichens coverage are developed in permafrost environment with an active layer depth of 15-150 cm. Soil organic C content (0.16-1.6%) and large variations of P, K and N contents are related to ornithogenic activity. Soils on moraines and platforms show differences that reflect the more recent exposure of moraines that preserve most the characteristics of the parent material. More vegetated soils on platforms show Cs-137 and Pb-210(ex) activities (11 and 25 Bq kg(-1), respectively) at the topsoil whereas absence of Cs-137 and depleted levels of Pb-210(ex) occurred in more recently exposed and less developed soils on moraines. Fallout radionuclides are good tracers for identifying characteristics of soil development and providing information on environmental changes of interest to understand the soil response to actual changes in unstable paraglacial environments.

期刊论文 2018-09-01 DOI: 10.1002/ldr.2987 ISSN: 1085-3278
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