Meltwater Samples Research Articles

Soil water sources and their implications for vegetation restoration in the Three-Rivers Headwater Region during different ablation periods

Abstract. Amid global warming, the timely supplementation of soil water is crucial for the effective restoration and protection of the ecosystem. It is therefore of great importance to understand the temporal and spatial variations of soil water sources. The research collected 2451 samples of soil water, precipitation, river water, ground ice, supra-permafrost water, and glacier snow meltwater in June, August, and September 2020. The goal was to quantify the contribution of various water sources to soil water in the Three-Rivers Headwater Region (China) during different ablation periods. The findings revealed that precipitation, ground ice, and snow meltwater constituted approximately 72 %, 20 %, and 8 % of soil water during the early ablation period. The snow is fully liquefied during the latter part of the ablation period, with precipitation contributing approximately 90 % and 94 % of soil water, respectively. These recharges also varied markedly with altitude and vegetation type. The study identified several influencing factors on soil water sources, including temperature, precipitation, vegetation, evapotranspiration, and the freeze–thaw cycle. However, soil water loss will further exacerbate vegetation degradation and pose a significant threat to the ecological security of the “Chinese Water Tower”. It emphasizes the importance of monitoring soil water, addressing vegetation degradation related to soil water loss, and determining reasonable soil and water conservation and vegetation restoration models.

Snow sampling strategy can bias estimation of meltwater fractions in isotope hydrograph separation

The Isotope based Hydrograph Separation (IHS) has been instrumental in understanding the partitioning of streamflow sources and processes. However, uncertainties persist in the accuracy of IHS estimations and the appropriate definition and sampling of endmembers. To address these uncertainties, we used field data of snowpack, snowfall, and snow meltwater isotopes (δ18O) from Pallas, Northern Finland to estimate the total meltwater contribution during the snowmelt period. We investigated the biases resulting from the application of different sampling strategies for event water endmember. The total meltwater contribution to streamflow was 59.6 % (±2% uncertainty) using the time-variant rolling runoff-corrected melt flux-weighted meltwater 18O isotope value. However, replacing it with either snowfall or winter snowpack 18O isotope weighted average values underestimated the meltwater contribution by 17.8 % or 22.6 %, respectively. Conversely, using time-variant instantaneous meltwater 18O isotope values overestimated the meltwater contribution by only 1.5 %. These discrepancies highlight the importance of choosing the appropriate endmember isotopes in IHS. The large differences in meltwater contribution for a 2-week peak discharge period based on different endmembers can lead to different interpretations of hydrological, ecohydrological, and biogeochemical processes. Thus, to better understand streamflow generation processes, we suggest using rolling runoff-corrected meltwater 18O or 2H isotope values in the IHS. In the absence of meltwater samples, the 18O or 2H isotope values of snowpack samples during the peak melt season may provide reasonable estimates of the meltwater contribution, with some minor underestimations. Our study highlights the importance of appropriate event meltwater endmember selection and sampling methodology for the IHS.

Distribution, composition and risk assessment of PAHs and PCBs in cryospheric watersheds of the eastern Tibetan Plateau

Polycyclic Aromatic Hydrocarbons (PAHs) and Polychlorinated Biphenyls (PCBs) are significant components of persistent organic pollutants (POPs) and pose a threat to both ecosystems and human health. To explore their spatial distribution, origins, and risk assessment, we collected 25 glacial meltwater and downstream river water samples in the eastern Tibetan Plateau (including the Qilian Mountains in the northeast) during the summer of 2022 (June–July). Our results showed that ∑PAHs and ∑PCBs were present in a wide range from ND-1380 ng/L and ND-1421 ng/L, respectively. Compared to other studies worldwide, the ∑PAHs and ∑PCBs in the Hengduan Mountains were at high levels. The PAHs and PCBs mainly consisted of low-molecular-weight homologs, including Ace, Flu, Phe, and PCB52. Phe was the primary component of PAHs. Glacial meltwater samples generally exhibited low concentration of PAHs and PCB52, whereas downstream river water samples typically showed high concentration of PAHs and PCB52. We attributed this characteristic to the influence of pollutants physicochemical properties, altitude effect, long-range transport (LRT), and local environmental conditions. In the eastern Tibetan Plateau glacier basin (especially in the Hailuogou watersheds), the concentration of PAHs and PCB52 in runoff generally increased with decreasing elevation. We believe that the primary factor affecting the concentration of PAHs and PCB52 in the region is the difference in local human activity inputs from various altitudes. The composition characteristics of PAHs and PCBs suggested that incomplete coal combustion and coking discharge mainly caused PAHs, while the combustion of coal and charcoal and the release of capacitors primarily caused PCBs. We assessed the carcinogenic risk of PAHs and PCBs in the glacier basin of the TP and found that the potential threat of PAHs was stronger than that of PCBs. Overall, this study provides new insights into the ecological security of water resources in eastern Tibetan Plateau. It is significant for controlling PAHs and PCBs emissions, assessing the ecological environment of the glacier watershed, and regional human health.

Analysis of Data on Air Pollutants in the City by Machine-Intelligent Methods Considering Climatic and Geographical Features

In the world, air pollution ranks among the primary sources of risk to human health and the environment. To assess the risk of impact of atmospheric pollution, a comprehensive research cycle was designed to develop a unified ecosystem for monitoring air pollution in industrial cities in Kazakhstan. Research involves analyzing data for the winter period from 20 automated monitoring stations (AMS) located in Almaty and conducting chemical-analytical studies of snowmelt water samples from 22 points to identify such pollutants as fine particulate matters, petroleum products, and heavy metals. Research includes a bio-experiment involving the cultivation of watercress on samples of melt water collected from snow cover to examine the effects of pollution on plants. In the framework of this research, we determined API based on data obtained from AMS. In order to determine the influence of atmospheric pollution on the environment, a multiple regression model was developed using machine learning algorithms to reveal the relationship between the bio-experiment data and data on pollutants of chemical-analytical research. The results revealed a wide spread of pollutants in the snow cover of the urban environment, a correlation between pollutants in the snow cover and the airspace of the city, and their negative impact on flora.

Contribution of the cryosphere to runoff in “Chinese water tower” based on environmental isotopes

Cryospheric meltwater is an important runoff component and it profoundly influences changes in water resources in the Tibetan Plateau. Significant changes in runoff components occur in the three-river headwater region (TRHR), which is an important part of “Chinese Water Tower” due to climate warming. However, these effects remain unclear owing to the sparse and uneven distribution of monitoring sites and limited field investigations. Quantifying the contribution of cryospheric meltwater to outlet runoff is a key scientific question that needs to be addressed. In this study, we analyzed 907 precipitation, river water, ground ice, supra-permafrost water, and glacier snow meltwater samples collected from October 2019 to September 2020 in the TRHR. The following results were obtained: (1) There was significant spatio-temporal variation in stable isotopes in different waters; (2) The seasonal trends of stable isotopes for different waters, the relationship between each water body and the local meteoric water line (LWML) confirmed that river water was mainly recharged by precipitation, supra-permafrost water, and glacier snow meltwater; (3) Precipitation, supra-permafrost water, and glacier snow meltwater accounted for 52%, 39%, and 9% of river water, respectively, during the ablation period according to the end-member mixing analysis (EMMA); (4) In terms of future runoff components, there will be many challenges due to increasing precipitation and evaporation, decreasing snow cover, glacier retreat, and permafrost degradation. Therefore, it is crucial to establish the “star-machine-ground” observation networks, forecast extreme precipitation and hydrological events, build the “TRHE on the Cloud” platform, and implement systematic hydraulic engineering projects to support the management and utilization of water resources in the TRHR. The findings of environmental isotope analysis provide insights into water resources as well as scientific basis for rational use of water resources in the TRHR.

The Spatiotemporal Variability of Snowpack and Snowmelt Water 18O and 2H Isotopes in a Subarctic Catchment

AbstractThis study provides a detailed characterization of spatiotemporal variations of stable water 18O and 2H isotopes in both snowpack and meltwater in a subarctic catchment. We performed extensive sampling and analysis of snowpack and meltwater isotopic compositions at 11 locations in 2019 and 2020 across three different landscape features: (a) forest hillslope, (b) mixed forest, and (c) open mires. The vertical isotope profiles in the snowpack's layered stratigraphy presented a consistent pattern in all locations before snowmelt, and isotope profiles homogenized during the peak melt period; represented by a 1–2‰ higher 18O value than prior to melting. Our data indicated that the liquid‐ice fractionation was the prime reason that caused the depletion of heavy isotopes in initial meltwater samples prior to the peak melt period. The liquid‐ice fractionation was influenced by snowmelt rate, with higher fractionation during slow melt. The kinetic liquid‐ice fractionation was evident only in close examination of meltwater lc‐excess values, not 18O values alone. Meltwater was isotopically heavier and more variable than the depth‐integrated snowpack; the weighted mean of meltwater isotope values was higher by 0.62–1.33‰ 18O than the weighted mean of snowpack isotope values in forest hillslope and mixed forest areas, and 1.51–6.37‰ 18O in open mires. Our results reveal close to 3.1‰ 18O disparity between the meltwater and depth‐integrated snowpack isotope values prior to the peak melt period, suggesting that proper characterization of meltwater 18O and 2H values is vital for tracer‐based ecohydrological studies and models.

Cultivable bacteria in the supraglacial lake formed after a glacial lake outburst flood in northern Pakistan.

Recently, a supraglacial lake formed as a result of a glacial lake outburst flood (GLOF) in the Dook Pal Glacier. Lake debris and meltwater samples were collected from the supraglacial lake to determine bacterial diversity. Geochemical analyses of samples showed free amino acids (FAAs), anions, cations, and heavy metals. Comparable viable bacterial counts were observed in meltwater and debris samples. Using R2A media, a total of 52 bacterial isolates were identified: 40 from debris and 12 from meltwater. The relative abundance of Gram-positive (80.8%) bacteria was greater than Gram-negative (19.2%). Molecular identification of these isolates revealed that meltwater was dominated by Firmicutes (41.6%) and Proteobacteria (41.6%), while lake debris was dominated by Firmicutes (65.0%). The isolates belonged to 14 genera with the greatest relative abundance in Bacillus. Tolerance level of isolates to salts was high. Most of the Gram-positive bacteria were eurypsychrophiles, while most of the Gram-negative bacteria were stenopsychrophiles. Gram-negative bacteria displayed a higher minimum inhibitory concentration of selected heavy metals and antibiotics than Gram-positive. This first-ever study of culturable bacteria from a freshly formed supraglacial lake improves our understanding of the bacterial diversity and antibiotic resistance released from the glaciers as a result of GLOF.

Distribution and sources of REEs in suspended particulate matter of cryospheric water in northeast Tibetan plateau

Rare earth elements (REE) are widely used as tracers for surface processes due to their zonal differences in composition and special geochemical indicators. In this study, we collected 30 glacial meltwater samples from a large area of the northeastern Tibetan Plateau region and analyzed the REE composition of suspended particulate matter (SPM, d > 0.45 μm) to explore the spatial distribution, origins and the influencing factors of REE in SPM. Results suggested that chondrite-normalized REE distribution patterns were characterized by steep LREE and relatively flat HREE, which is different from that of PAAS-normalized. The high (La/Sm)N ratio and low (Gd/Yb)N ratio indicated that the degree of LREE fractionation was higher than that of HREE. We found an obvious correlation between REE concentration and SPM concentration, indicating that REE concentration in glacial runoff was significantly affected by SPM contents. It was found that Ce/Ce* decreased first and then increased with the decrease of altitude in the glacial river basins, which may contribute to weathering, oxidation, and physicochemical property of the water environment in the study areas. At the glacier forefield, the degree of weathering is intense, resulting in the highest Ce/Ce* value in the altitude between 3200 and 4800 m. However, this was not obvious in non-glacial regions. Compared REE geochemical parameters (e.g., LREE/HREE, Eu/Eu*, LaN/SmN) of SPM in the glacier basin with those of Asian potential dust sources and long-range transport (LRT) dust deposited on the studied glaciers, we found that the SPM in the glacial river basins is affected by lithology of parent materials, the LRT dust from the surrounding deserts, the release of ice/snow dust, and the detrital material from local rock weathering. This study provides a new perspective on the composition, distribution and variation in the altitude of REE in the glacial river basin of the northeast TP, and thus is of significance to improve the understanding of the source and migration process of REE in SPM of glacial river basins.

Understanding the hydrochemical functioning of glacierized catchments of the Upper Indus Basin in Ladakh, Indian Himalayas.

Recent studies have endorsed that surface water chemical composition in the Himalayas is impacted by climate change-induced accelerated melting of glaciers. Chemical weathering dynamics in the Ladakh region is poorly understood, due to unavailability of in situ dataset. The aim of the present study is to investigate how the two distinct catchments (Lato and Stok) drive the meltwater chemistry of the Indus River and its tributary, in the Western Himalayas. Water samples were collected from two glaciated catchments (Lato and Stok), Chabe Nama (tributary) and the Indus River in Ladakh. The mildly alkaline pH (range 7.3-8.5) and fluctuating ionic trend of the meltwater samples reflected the distinct geology and weathering patterns of the Upper Indus Basin (UIB). Gibbs plot and mixing diagram revealed rock weathering outweighed evaporation and precipitation. The strong associations between Ca2+-HCO3-, Mg2+-HCO3-, Ca2+-Mg2+, Na+-HCO3-, and Mg2+-Na+ demonstrated carbonate rock weathering contributed to the major ion influx. Principal component analysis (PCA) marked carbonate and silicates as the most abundant minerals respectively. Chemical weathering patterns were predominantly controlled by percentage of glacierized area and basin runoff. Thus, Lato with the larger glacierized area (~ 25%) and higher runoff contributed low TDS, HCO3-, Ca2+, and Na+ and exhibited higher chemical weathering, whereas lower chemical weathering was evinced at Stok with the smaller glacierized area (~ 5%). In contrast, the carbonate weathering rate (CWR) of larger glacierized catchments (Lato) exhibits higher average value of 15.7 t/km2/year as compared to smaller glacierized catchment (Stok) with lower average value 6.69 t/km2/year. However, CWR is high in both the catchments compared to silicate weathering rate (SWR). For the first time, in situ datasets for stream water chemical characteristics have been generated for Lato and Stok glaciated catchments in Ladakh, to facilitate healthy ecosystems and livelihoods in the UIB.

Assessing the influence of water sampling strategy on the performance of tracer-aided hydrological modeling in a mountainous basin on the Tibetan Plateau

Abstract. Tracer-aided hydrological models integrating water isotope modules into the simulation of runoff generation are useful tools to reduce uncertainty of hydrological modeling in cold basins that are featured by complex runoff processes and multiple runoff components. However, there is little guidance on the strategy of field water sampling for isotope analysis to run tracer-aided hydrological models, which is especially important for large mountainous basins on the Tibetan Plateau (TP) where field water sampling work is highly costly. This study conducted a set of numerical experiments based on the THREW-T (Tsinghua Representative Elementary Watershed - Tracer-aided version) model to evaluate the reliance of the tracer-aided modeling performance on the availability of site measurements of water isotope in the Yarlung Tsangpo river (YTR) basin on the TP. Data conditions considered in the numerical experiments included the availability of glacier meltwater isotope measurement, quantity of site measurements of precipitation isotope, and the variable collecting strategies for stream water samples. Our results suggested that (1) in high-mountain basins where glacier meltwater samples for isotope analysis are not available, estimating glacier meltwater isotope by an offset parameter from the precipitation isotope is a feasible way to force the tracer-aided hydrological model. Using a set of glacier meltwater δ18O that were 2 ‰–9 ‰ lower than the mean precipitation δ18O resulted in only small changes in the model performance and the quantifications of contributions of runoff components (CRCs, smaller than 5 %) to streamflow in the YTR basin. (2) The strategy of field sampling for site precipitation to correct the global gridded isotope product of isoGSM (isotope-incorporated global spectral model) for model forcing should be carefully designed. Collecting precipitation samples at sites falling in the same altitude tends to be worse at representing the ground pattern of precipitation δ18O over the basin than collecting precipitation samples from sites in a range of altitudes. (3) Collecting weekly stream water samples at multiple sites in the wet and warm seasons is the optimal strategy for calibrating and evaluating a tracer-aided hydrological model in the YTR basin. It is highly recommended to increase the number of stream water sampling sites rather than spending resources on extensive sampling of stream water at a sole site for multiple years. These results provide important implications for collecting site measurements of water isotopes for running tracer-aided hydrological models to improve quantifications of CRCs in high-mountain basins.

CH4 and CO2 observations from a melting high mountain glacier, Laohugou Glacier No. 12

With global warming, glaciers in the high mountains of China are retreating rapidly. However, few data have been reported on whether greenhouse gases from these glaciers are released into the atmosphere or absorbed by glacial meltwater. In this study, we collected meltwater and ice samples from Laohugou Glacier No. 12 in western China and measured CH4 and CO2 concentrations. Meltwater from the glacier terminus was continually sampled between 3 and 5 August 2020 to measure CH4 and CO2 concentrations. The results demonstrated that meltwater is a source of CH4 because the average saturations are over 100%. It could be concluded that CH4 in the atmosphere can be released by glacial meltwater. However, the CO2 saturations are various, and CO2 fluxes exhibit positive (released CO2) or negative (absorbed CO2) values because the water and atmospheric conditions are variable. More importantly, the CH4 and CO2 concentrations were higher in meltwater samples from the glacier terminus than in samples from the surface ice (including an ice core) and a surface stream. Although the meltwater effect from the upper part of the glacier cannot be excluded, we speculated that subglacial drainage systems with an anaerobic environment may represent the CH4 source, but it needs to be further investigated in the future. However, high mountain glaciers are currently ignored in global carbon budgets, and the increased melting of glaciers with global warming may accelerate the absorption of much more CO2 and lead to the release of CH4.

Solid-phase extraction of alkylphosphonic and O-alkyl alkylphosphonic acids followed by HPLC separation using porous graphitic carbon sorbent

An HPLC separation of alkyl phosphonic acids on porous graphitic carbon adsorbent Hypercarb, based upon a step gradient of formic acid concentration in an aqueous mobile phase, was evaluated in this study. Analytes were detected by single quadrupole and triple quadrupole MS. Good separation was achieved for methyl phosphonic acid, ethylphosphonic acid, n-propylphosphonic acid, isopropylphosphonic acid, ethyl methylphosphonic acid, isopropyl methylphosphonic acid, isobutyl methylphosphonic acid, pinacolyl methylphosphonic acid. Solid-phase extraction of these analytes on Hypercarb was also proposed, desorption was carried out with aqueous ammonium formate and water-methanol mixtures. LODs were 0.1–0.2 ng mL−1 for these analytes without SPE; solid-phase extraction resulted in the decrease of LODs at least 100-fold. Accuracy was proven by analyses of spiked samples of river water and snow meltwater.

Mercury sources and physicochemical characteristics in ice, snow, and meltwater of the Laohugou Glacier Basin, China.

In this work, samples of surface snow, surface ice, snow pit and meltwater from the Laohugou Glacier No. 12 on the northern edge of Tibetan Plateau (TP) were collected during the summer of 2015. The average concentration of Hg in surface snow/ice was 22.41 ng L-1, while the percentage of dissolved mercury (HgD) was observed to be around 26%. An altitudinal magnification of Hg was not observed for surface snow; however, in contrast, a significant positive magnification of Hg with altitude was observed in the surface ice. A higher concentration of Hg corresponded with the dust layer of the snow pit. It was observed that about 42% of Hg was lost from the surface snow when the glacier was exposed to sunlight within the first 24 h indicating some Hg was emitted back to the atmosphere while some were percolated downwards. The result from the principal component analysis (PCA) showed that the sources of Hg in Laohugou Glacier No. 12 were from crustal and biomass burning. Finally, it was estimated that total export of Hg from the outlet river of Laohugou glacier No. 12 in the year 2015 was about 1439.46 g yr-1 with yield of 22.77 μg m2 yr-1. This study provides valuable insights for understanding the behavior of Hg in the glacier of the northern Tibetan Plateau.

Molecular Signatures of Glacial Dissolved Organic Matter From Svalbard and Greenland

AbstractGlaciers and ice sheets cover over 10 % of Earth's land surface area and store a globally significant amount of dissolved organic matter (DOM), which is highly bioavailable when exported to proglacial environments. Recent rapid glacier mass loss is hypothesized to have increased fluxes of DOM from these environments, yet the molecular composition of glacially derived DOM has only been studied for a handful of glaciers. We determine DOM composition using ultrahigh resolution mass spectrometry from a diverse suite of Arctic glacial environments, including time series sampling from an ice sheet catchment in Greenland (Russell Glacier) and outflow from valley glaciers in catchments with varying degrees of glacial cover in Svalbard. Samples from the Greenland outflow time series exhibited a higher degree of similarity than glacier outflow between glaciers in Svalbard; however, supraglacial meltwater samples from Greenland and Svalbard were more similar to each other than corresponding glacial outflow. Outflow from Russell Glacier was enriched in polyphenolic formulae, potentially reflecting upstream inputs from plants and soils, or inputs from paleosols overridden by the ice sheet, whereas Svalbard rivers exhibited a high level of molecular richness and dissimilarity between sites. When comparing DOM compositional analyses from other aquatic systems, aliphatic, and peptide‐like formulae appear particularly abundant in supraglacial meltwater, suggesting the DOM quickly metabolized in previous incubations of glacial water originates from energy‐rich supraglacial sources. Therefore, as glaciers lose mass across the region, higher‐quality fuel for microbial degradation will increase heterotrophy in coastal systems with ramifications for carbon cycling.

Physicochemical Impacts of Dust Storms on Aerosol and Glacier Meltwater on the Northern Margin of the Taklimakan Desert

To analyze the impacts of dust storms on the atmospheric and meltwater environment, intensive and simultaneous sampling for aerosols and meltwater on the terminal moraine (41°73′ N, 79°88′ E, 3,789 m a.s.l.) of Qingbingtan Glacier No. 72 (Glacier No. 72) on the northern margin of the Taklamakan Desert were conducted during the summer of 2008. Aerosol and meltwater chemistry (including the species of Na+, K+, Mg2+, Ca2+, NH4+, Cl−, SO42−, and NO3−) was analyzed by ion chromatography. The results indicated that the major anions and cations in the samples were SO42− and Ca2+, respectively. In the dust event, the average value of aerosol ions was 566.91 neq·m−3, which was nearly five times that under nondust conditions (115.58 neq·m−3). In addition, in the meltwater samples, the sum of ion concentrations ranged from 31.26 to 180.98 mg·L−1, with an average of 76.40 mg·L−1. When a dust storm occurred, the ion concentrations in these two media increased significantly and simultaneously, but with different trends due to the different influencing factors. That is, the atmospheric environment was significantly affected by the dust storm. According to the correlation analysis and principal component analysis, the water-soluble ions, such as SO42−, Cl−, Na+, K+, Mg2+, and Ca2+, originated from natural sources, while NH4+ and NO3− originated from anthropogenic sources. The results of the air mass trajectory suggested that the regional dust storms caused by the air masses originating from Eastern Europe and Siberia had a significant influence on the glacial environment.

Ice sheets mobilize trace elements

Earth’s two remaining ice sheets, also called continental glaciers, are more active geochemists than we previously knew, according to a new study. Researchers led by Jon Hawkings, a biogeochemist at Florida State University and the German Research Center for Geosciences, measured the abundance of 17 trace elements in samples of meltwater from the Greenland Ice Sheet and a lake beneath the Antarctic Ice Sheet. They found that these water samples are more enriched in important micronutrients such as iron compared with rivers and the surrounding ocean ( Proc. Natl. Acad. Sci. U.S.A. 2020, DOI: 10.1073/pnas.2014378117 ). The trace elements can be found fully dissolved or suspended as nanoparticles, and they likely come from the bedrock beneath the frozen giants. That’s because ice sheets are “natural bulldozers” that pulverize landscapes as they move, and water trapped in subglacial lakes can liberate minerals from the surrounding rock, Hawkings says. “We didn’t have

Voices from the Roof of the World

Glacier-based mountain water systems are the water towers of the world, and billions are dependent on the vital services they provide. In an effort to better understand the effects of climate change on the glaciers of the Hindu Kush-Himalaya, National Geographic and Tribhuvan University conducted a multidisciplinary expedition to Mount Everest. These are the voices from that journey.

Investigation of the spatio-temporal heterogeneity and optical property of water-soluble organic carbon in atmospheric aerosol and snow over the Yulong Snow Mountain, southeastern Tibetan Plateau

Atmospheric aerosols are a branch of active research in recent decades. The deposition of light-absorbing substances on high-altitude glaciers causes substantial adverse impacts on the cryospheric environment, cryosphere-hydrology, and climate system. Although, the concentrations of water-soluble organic carbon (WSOC) in snow/ice on glaciers of Tibetan Plateau (TP) have been reported, their transfer processes and optical properties in the context of summer precipitation-atmosphere-snow-river water continuum are seldom studied. In this study, we have systematically examined some scientific issues associated with WSOC concentrations and light absorption properties of WSOC in various forms of samples from the Mt. Yulong region. Statistical results demonstrate that the spatial distribution of WSOC in the snow of Baishui glacier was heterogeneous. The average WSOC concentrations of each snowpit were significantly decreased, and its light-absorbing properties were significantly elevated with the time extension. Aerosol WSOC concentrations and light absorption have distinct spatial disparity and seasonal variation. Pre-monsoon and monsoon have the highest and lowest WSOC content, respectively. Whereas the light-absorbing properties present contrasting seasonal trends. Rivers of which runoff was supplied by glacier meltwater have significantly lower WSOC concentrations (e.g., 0.42 ± 0.03 mg L−1) compared with other forms of water bodies. Mass absorption cross-section of WSOC (MAC-WSOC) in multiple snow and meltwater samples was significantly different and type-dependent. Atmospheric aerosol has the lowest MAC-WSOC value among the four types of samples, which was likely associated with exhaust emissions from private vehicles and tour buses. Statistical results indicated that the average AAE330-400 values of various snow/ice samples are subequal. Snow of glaciers supplies a desirable platform for the deposition of gaseous materials which experienced long-range transport in high altitude zones. Biomass-burning emissions made an immense contribution to the WSOC deposition over the study area, as demonstrated by the distribution of active fire points. However, this preliminary study represents the first systematic investigation of WSOC deposition in southeastern TP. Further robust in-situ field investigations and laboratory measurements are urgently necessary to improve our understanding of the transfer process and optical property of WSOC.

Melting Himalayan Glaciers Threaten Domestic Water Resources in the Mount Everest Region, Nepal

Retreating glaciers and snowpack loss threaten high-altitude communities that rely upon seasonal melt for domestic water resources. But the extent to which such communities are vulnerable is not yet understood, largely because melt contribution to water supplies is rarely quantified at the catchment scale. The Khumbu Valley, Nepal is a highly glaciated catchment with elevations ranging from 2000-8848 m above sea level, where more than 80% of annual precipitation falls during the summer monsoon from June to September. Samples were collected from the rivers, tributaries, springs, and taps along the major trekking route between Lukla and Everest Base Camp in the premonsoon seasons of 2016-2017. Sources were chosen based upon their use by the communities for drinking, cooking, bathing and washing, so the sample suite is representative of the local domestic water supply. In addition, meltwater samples were collected directly from the base of the Khumbu Glacier, and several rain samples were collected throughout the study site. Meltwater contribution was estimated from d 18 O isotopic data using a two-component mixing model with the Khumbu glacial melt and pre-monsoon rain as endmembers. Results indicate between 34-90% of water comes from melt during the dry, pre-monsoon season, with an average meltwater contribution of 65%. With as much as two-thirds of the dry-season domestic water supply at risk, the communities of the Khumbu Valley are extremely vulnerable to the effects of climate change as glaciers retreat and snowpack declines.

Fungal recovery and characterization from Hindu Kush mountain range, Tirich Mir glacier, and their potential for biotechnological applications.

The Hindu Kush mountains spread over Northern areas of Pakistan having hundreds of glaciers representing a unique ecosystem driven by the specific geochemistry and climate. The current study measured the distribution of culturable fungi in Tirich Mir glacier, Hindu Kush range, and the potential of these isolates to show antimicrobial activity and produce biotechnologically important enzymes. Samples of glacial ice, sediments, and meltwater were collected from Tirich Mir glacier, and 46 fungal strains were isolated and characterized for identity and biotechnological applications. The findings revealed Penicillium (10) as the most common genus, followed by Alternaria (9), Cladosporium (7), Coprinopsis, two isolates each belonging to genus Phoma, Ulocladium, Epicoccum, Onygenales, and Didymella, and one isolate of genus Davidiella, Aspergillus, Geomyces, Dothideomycetes, Pseudogymnoascus, Irpex, Scopulariopsis, Ascochyta, Tomicus, and Davidiellaceae. Davidiella tassiana HTF9 showed growth in the presence of 18% NaCl and pH 2, 3, 5, 7, 9, and 11. The isolates Ulocladium sp. and Onygenales sp. inhibited the growth of test fungi, Gram-negative and positive bacteria. Fungal strains were capable of producing cold-active enzymes, including cellulase, lipase, amylase, and deoxyribonuclease. The isolate Penicillium chrysogenum HTF24 was an efficient producer of amylase, deoxyribonuclease, and cellulase. The fungi of high-altitude glaciers are potent candidates for biotechnological applications; however, studies using more sensitive techniques are needed for further exploration.