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Glaciers are recognized as repositories for atmospheric pollutants, however, due to climate change and enhanced melting rates, they are rapidly transitioning from being repositories to secondary sources of such apollutants. Artificial radionuclides are one of the pollutants found on glaciers that efficiently accumulate onto glacier surfaces within cryoconite deposits; a dark, often biogenic sediment. This work provides information about the accumulation, distribution and sources of plutonium (Pu) isotopes in cryoconite samples from glaciers worldwide. Plutonium is an artificial radionuclide spread into the environment in the last decades as a consequence of nuclear test explosions, accidents and nuclear fuel re-processing. Samples collected from 49 glaciers across nine regions of Earth are considered. Activity concentrations of plutonium in cryoconite are orders of magnitude higher than in other environmental matrices typically used for environmental monitoring (e.g. lichens, mosses, soils and sediments), particularly in the Northern Hemisphere. Isotopic ratios indicate that plutonium contamination of cryoconite is dominated by the global signal of stratospheric fallout related to atmospheric nuclear tests. However, specific glaciers in Svalbard reveal a signature compatible with a contribution from the re-entry of the SNAP-9A satellite in 1964, which was equipped with a 238Pu radioisotope thermoelectric generator. Similarly, an excess of 238Pu is observed in cryoconite from the Exploradores Glacier (Chile). This could be associated with the November 1996 crash of the automatic Interplanetary Station "Mars '96" which was carrying a 238Pu thermoelectric generator. This is the first time ever that an isotopic evidence for this event is reported. These findings highlight the role that cryoconite can play in reconstructing the radioactive contamination history of different glaciated regions of the Earth.

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Glaciers are considered secondary sources of pollutants, including radioisotopes such as Cesium or Plutonium, with heightened concentrations compared to other ecosystems. The predicted melting of glaciers poses a substantial risk of releasing stored radioisotopes, yet understanding the glacier-specific factors influencing their concentration remains limited. This study investigates the relationship between glacier altitude, surface area, organic matter content in dark supraglacial sediment (cryoconite), precipitation, and activity concentrations of natural (210Pb) and anthropogenic radionuclides (137Cs and 241Am) across 19 Alpine glaciers. Results indicate that radioisotope concentrations depend on organic matter content in the cryoconite, highlighting the role of biotic-abiotic interactions in pollutant accumulation on glaciers. Moreover, 210Pb activity concentration decreases with glacier altitude, likely due to atmospheric variations in 222Rn. Water precipitation events, such as during peaks in 137Cs deposition and after the Chernobyl Nuclear Power Plant disaster, do not impact current activity concentrations. Importantly, radioisotope concentrations in cryoconite are higher on smaller glaciers. This directly supports the hypothesis that the cryoconite retains a significant share of radioisotopes stored in the ice during intensive melting. Since many small glaciers in the Alps are predicted to disappear within the next 50 years, we anticipate release of radioisotopes to mountain ecosystems might be higher than previously forecasted.

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Ongoing warming is leading to the accelerated shrinkage of glaciers located on Arctic islands. Consequently, the influence of glacial meltwater on phytoplankton primary production in Arctic bays becomes critically important in an era of warming. This work studies the spatiotemporal variation of primary production and chlorophyll a concentration in the bays along the eastern coast of the Novaya Zemlya archipelago. Data were collected during nine cruises performed from July to October (2013-2022). The effect of underwater photosynthetically available radiation (PAR) and nutrients on primary production was assessed separately for bays influenced by glacial meltwater (glacial bays) and those without such influence (non-glacial bays). The median value of water column-integrated primary production (IPP) for all bays was 38 mgC m-2 d-1, characterizing them as oligotrophic areas. IPP in non-glacial bays was found to be 2.3-fold and 1.4-fold higher than that in glacial bays during summer and autumn, respectively. Underwater PAR was the main abiotic factor determining IPP during the ice-free period. In the entire bays nutrient concentrations were high, exceeding the limiting values for growth and photosynthesis of phytoplankton. It was concluded that the high turbidity from glacial meltwater runoff leads to decreased underwater PAR and, consequently, to a decline in IPP. This study demonstrates that rapid warming could have a negative impact on the productivity of high Arctic bays and their adjacent areas.

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Ice-covered and remote landscapes in the McMurdo Dry Valleys, Antarctica, are likely seeded by aeolian transport of biological material from ice-free local or distant environments. Here, we report the genome sequences of seven bacteria isolated from aerosols collected on top of two dry valley glaciers.

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Interactions between coastal waters and marine-terminating glaciers in the Polar Regions play a significant role in global sea level rise fueled by a rapidly warming Arctic. The risk of glacier calving, and the abundance of ice, can make it impossible for surface vessels to access the waters near glacier termini. Alternative methods using manned aircraft are expensive. As a result, oceanographic measurements are limited near glacier termini. We present an uncrewed aerial vehicle (UAV) with an on-board winch system that allows oceanographic profiling in remote, hazardous areas using a commercial conductivity, temperature, and depth (CTD) sensor payload. The UAV is optimized for easy handling and deployment and is capable of high-speed and efficient cruise flight. An autopilot system provides pilot assistance and autonomous flight capabilities. The total weight of the UAV including payload is 6.5 kg with an endurance of 24 min. Testing of the system was conducted in South Greenland during winter conditions in March 2023 with successful profiles collected near a glacier terminus (<5 m) and in small openings in ice mélange (2.2 m). The system proved capable, reliable, and efficient. Further development of the system will allow other sensors for an even more flexible measurement suite.

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Small microplastics (SMPs < 100 µm) can easily be transported over long distances far from their sources through the atmospheric pathways and reach even remote regions, including the Arctic. However, these sizes of MPs are mostly overlooked due to different analytical challenges; besides, their pathways through atmospheric depositions, such as snow depositions, are mostly unknown. The spatial variability in bulk snow samples was investigated for the first time in distinct sites (e.g., glaciers) near Ny Ålesund, the world-known northernmost permanent research settlement in the Svalbard Islands, to better comprehend the presence of SMP pollution in snow. Seasonal snow deposited over the tundra and the summits of different glaciers were also sampled. A sampling procedure was designed to obtain representative samples while minimizing plastic contamination, thanks to rigorous quality assurance and quality control protocol. SMPs' weight (µg SMP L-1) and deposition load (mg SMPs m-2) result from being lower in the remote glaciers, where they may be subject to long-range transport. The SMPs' minimum length was 20 µm, with the majority less than 100 µm. Regarding their size distribution, there was an increase in the size length deriving from the local input of the human presence near the scientific settlement. The presence of some polymers might be site-specific in relation to the pathways that affect their distribution at the sites studied. Also, from the snow surface layer collected at the same sites to evaluate the variability of SMPs during specific atmospheric deposition events, the results confirmed their higher weight and load in surface snow near the scientific settlement compared to the glaciers. The results will enhance the limited knowledge of the SMPs in polar atmospheric compartments and deposition processes.

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Organophosphate esters (OPEs), extensively used as flame retardants, are widely detected in various regions and environments. The potential toxicity of OPEs has caused great concern in recent years. Based on the global distillation model, the Tien Shan glaciers, such as Urumqi Glacier No. 1, could be as a potential "sink" for OPEs. However, little is known about the concentration, distribution, potential sources, and ecological risks of OPEs in Tien Shan glaciers. In this study, fresh snow samples were collected at various altitudes on the Urumqi Glacier No. 1, eastern Tien Shan, China. The total concentrations of ten OPEs (Σ10OPEs) ranged from 116 to 152 ng/L. The most abundant OPE was tris-(2-chloroisopropyl) phosphate (TCIPP), contributing to 74 % of the total OPEs. Σ10OPEs, tri-n-butyl phosphate (TnBP), and TCIPP concentrations showed positive correlations with altitude, indicating the effect of cold condensation on OPEs deposition. Based on air mass back-trajectory analysis and principal component analysis, we found that emissions from both traffic and household products in indoor environment were the important sources, and OPEs on the Urumqi Glacier No. 1 might mainly originate from Europe. Our assessment also showed triphenyl phosphate (TPhP) posed a low ecological risk in snow. This is the first systematic study of OPEs on the Tien Shan glaciers.

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Glacier retreat is rapidly transforming some watersheds, with ramifications for water supply, ecological succession, important species such as Pacific salmon (Oncorhynchus spp.), and cultural uses of landscapes. To advance a more holistic understanding of the evolution of proglacial landscapes, we integrate multiple lines of knowledge starting in the early 1900s with contemporary data from the Taaltsux̱éi (Tulsequah) Watershed in British Columbia, Canada. Our objectives were to: 1) synthesize recent historical geography and Indigenous Knowledge, including glacier dynamics, and hydrology; 2) describe the limnology of a proglacial lake; 3) quantify decadal-scale downstream physical floodplain change; and 4) characterize riverine physical, chemical, and biological differences relative to distance from the proglacial lake. Since 1982, the Tulsequah Glacier has receded 0.07 km/yr, exposing a cold, deep, and growing proglacial lake. The downstream floodplain is rapidly changing; satellite imagery analysis revealed a 14 % increase in vegetation from 2003 to 2017 and Indigenous Knowledge described increases in vegetation and wildlife habitat over the last century. Contemporary measurements of physical-chemical water properties differed across sites representing the upper and lower watershed, and mainstem and off-channel habitats. Catches of juvenile salmonids in the upper watershed (closer to the glacier) were mostly limited to warmer, clearer groundwater-fed channels, whereas in the lower watershed there were salmonids in both groundwater-fed and mainstem habitats. There was limited zooplankton taxa diversity from the proglacial lake and benthic macroinvertebrates in the river. Collectively, our synthesis suggests that the transformation of proglacial landscapes experiencing rapid ice loss can be influenced by interlinked abiotic processes of glacier retreat, lake formation, and altered hydrology, as well as corresponding biological processes such as beaver repopulation, wetland formation, and riparian vegetation growth. These factors, along with expected increases to proglacial lake productivity and salmon habitat suitability, are an important consideration for forward-looking watershed management of glacier-fed rivers.

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This study investigates empirically how natural snow depth and permanent snow affect the number of new second homes in Norway. One out of four Norwegian municipalities is partly covered by glaciers and permanent snow. In the winter seasons of 1983-2020, there is a decline in snow depth from 50 to 35 cm on average (based on 41 popular second-home areas in the mountains). Results of the fixed effects Poisson estimator with spatial elements show that there is a significant and positive relationship between natural snow depth in the municipality and the number of second homes started. There is also a significant and negative relationship between the number of new second homes in the municipality and a scarcity of snow in the surrounding municipalities. However, the magnitude of both effects is small. Estimates also show a strong positive relationship between the proportion of surface covered by permanent snow or glaciers in the municipality and new second homes. This implies that a decline in permanent snow and glaciers may make these areas less attractive for the location of second homes.

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Pesticides, synthetic fragrances and polycyclic aromatic hydrocarbons contaminated two glacier-fed streams (Amola, Mandrone) and one spring (Grostè) in the Italian Alps. Ten compounds (chlorpyrifos (CPY), chlorpyrifos-methyl (CPY-m), galaxolide (HHCB), tonalide (AHTN), fluorene (Flu), phenanthrene (Phen), anthracene (Ant), fluoranthene (Fl), pyrene (Pyr), benzo[a]anthracene (BaA)) accumulated in aquatic larvae of chironomids (Diamesa steinboecki, D. latitarsis, D. bertrami, D. tonsa, D. zernyi, Pseudokiefferiella parva, Orthocladiinae) and tipulids. Their tissue concentrations (detected by gas chromatography coupled with mass spectrometry) ranged from 1.1 ± 0.1 ng/g d.w. (= dry weight) (CPY-m in D. tonsa from Amola) to 68.0 ± 9.1 ng/g d.w. (Pyr in D. steinboecki from Mandrone). HHCB, AHTN, and CPY, with one exception, were accumulated by all aquatic insects. Six compounds (CPY, CPY-m, HHCB, AHTN, Fl, Pyr) also contaminated carabids (Nebria germarii, N. castanea, N. jockischii) predating adults of merolimnic insects. Their tissue concentrations ranged from 1.1 ± 0.3 ng/g d.w. (CPY-m in N. germarii from Mandrone) to 84.6 ± 0.3 ng/g d.w. (HHCB in N. castanea from Grostè). HHCB and AHTN were accumulated by all Nebria species. Intersite and interspecies differences were observed, which might be attributed to different environmental contamination levels. There was a stronger similarity between species from the same site than among the same species from different sites, suggesting that uptake is not species specific. At all sites, the concentration of xenobiotics was higher in larvae than in water and comparable or higher in carabids than in larvae from the same site, suggesting trophic transfer by emerging aquatic insects to their riparian predators.

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This research focuses on a bibliometric analysis of research on aerosols' impact on the glaciers in the Himalayan glacier region published in journals from all subject categories based on the Science Citation Index Expanded, collected from the Web of Science and Scopus database between January 2002 and April 2022. The indexing phrases like "aerosol," "glacier," and "snow" are commonly used terms and have been utilized to collect the related publications for this investigation. The document selections were based on years of publication, authorship, the scientific output of authors, distribution of publication by country, categories of the subjects, and names of journals in which scholarly papers were published. The number of articles on aerosols accelerating the melting of glaciers shows a notable increase in recent years, along with more glacier melting results from countries involved in climate science research. People's Republic of China (382) was the country with the highest publication output on aerosols impacting the melting of glaciers. The USA (367) was the most cited country, with about 17,500 total citations and 80.40 average citations per year from January 2002 to April 2022. The results reveal that research trends in the glaciers on aerosols' impact on the glaciers have been attractive in recent years, and the number of articles in this field keeps increasing fast. This study offers opportunities to track research trends, identify collaboration prospects, and inform climate policy. Integrating data sources and engaging the public will further enhance the impact and relevance of this critical research field.

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Relics of World War One (WW1) were buried in alpine glaciers around 100 years ago. Today, these are emerging from the ice due to widespread glacier retreat, and are in direct contact with glacial meltwater-fed streams. To address a possible emergent contamination, we quantified major and trace elements (M-TEs) by mass spectrometry in water and larvae of Diamesa zernyi from three glacial streams fed by glaciers differently impacted by the Italian Austro-Hungarian war, in the Adamello-Presanella mountain range (Italian Alps): Lares and Presena, the two main battlefields, and Amola, 8 km from the front. M-TEs in stream water were interpreted using the crustal enrichment factor (EFc) while larval uptake was quantified by adopting the bioaccumulation factor (BAF). Despite low M-TEs concentrations in the water, in a range between 1 ng L-1 (Ag, Ta) and 1-2 mg L-1 (Al, Fe, Mg), low to moderate enrichments (10 ≥ EFc≥ 6) were observed for Sb and U in Presena and for Ag, As, Bi, Cd, Li, Mo, Pb, Sb and U in Lares. In addition, M-TE mass concentrations in larvae were up to ninety thousand times higher than in water, from 20 to 50 ng g-1 dry weight (d.w.; for Bi, Sb, Ta, Tl) to 1-4 mg g-1 d.w. (for Al, Fe, Na, and Mg). Larvae from Lares accumulated the largest amount of metals and metalloids, including those mostly used in the manufacture of artillery shells (As, Cu, Ni, Pb, Sb; BAFs from 375 to about 11,500). This was expected as most of the WW1 battles in this mountain range were fought on the Lares glacier, where the greatest number of war relics are emerging. These results provide preliminary evidence of water contamination and bioaccumulation of metals and metalloids by glacial fauna as a possible legacy of WW1 in the Alps.

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Atmospheric deposition on glaciers is a major source of legacy fallout radionuclides (FRNs) accumulating in cryoconite, a dark granular material with surface properties that efficiently bind FRN contaminants (specifically 137Cs; 210Pb; 241Am). Cryoconite-bound FRNs in glaciers can be released when they interact with and are transported by glacial meltwater, resulting in the discharge of amassed particulate contaminants into aquatic and terrestrial environments downstream. The environmental consequences of FRN release from the cryosphere are poorly understood, including impacts of cryoconite-sourced FRNs for alpine food chains. Consequently, there is limited understanding of potential health risks to humans and animals associated with the consumption of radiologically-contaminated meltwater. To assess the chemical availability of cryoconite-adsorbed FRNs we used a three-stage sequential chemical extraction method, applied to cryoconite samples from glaciers in Sweden and Iceland, with original FRN activity concentrations up to 3300 Bq kg-1 for 137Cs, 10,950 Bq kg-1 for unsupported 210Pb (210Pbun) and 24.1 Bq kg-1 for 241Am, and orders of magnitude above regional backgrounds. Our results demonstrate that FRNs attached to cryoconite are solubilized to different degrees, resulting in a stage-wise release of 210Pbun involving significant stepwise solubilization, while 137Cs and 241Am tend to be retained more in the particulate phase. This work provides an insight into the vulnerability of pristine glacial environments to the mobilization of FRN-contaminated particles released during glacier melting, and their potential impact on glacial-dependent ecology.

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The accumulation of fallout radionuclides (FRNs) from nuclear weapons testing and nuclear accidents has been evaluated for over half a century in natural environments; however, until recently their distribution and abundance within glaciers have been poorly understood. Following a series of individual studies of FRNs, specifically 137Cs, 241Am and 210Pb, deposited on the surface of glaciers, we now understand that cryoconite, a material commonly found in the supraglacial environment, is a highly efficient accumulator of FRNs, both artificial and natural. However, the variability of FRN activity concentrations in cryoconite across the global cryosphere has never been assessed. This study thus aims to both synthesize current knowledge on FRNs in cryoconite and assess the controls on variability of activity concentrations. We present a global database of new and previously published data based on gamma spectrometry of cryoconite and proglacial sediments, and assess the extent to which a suite of environmental and physical factors can explain spatial variability in FRN activity concentrations in cryoconite. We show that FRNs are not only found in cryoconite on glaciers within close proximity to specific sources of radioactivity, but across the global cryosphere, and at activity concentrations up to three orders of magnitude higher than those found in soils and sediments in the surrounding environment. We also show that the organic content of cryoconite exerts a strong control on accumulation of FRNs, and that activity concentrations in cryoconite are some of the highest ever described in environmental matrices outside of nuclear exclusion zones, occasionally in excess of 10,000 Bq kg-1. These findings highlight a need for significant improvements in the understanding of the fate of legacy contaminants within glaciated catchments. Future interdisciplinary research is required on the mechanisms governing their accumulation, storage, and mobility, and their potential to create time-dependent impacts on downstream water quality and ecosystem sustainability.

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Debris-covered glaciers (DCGs) are globally distributed and thought to contain greater microbial diversity than clean surface continental glaciers, but the ecological characteristics of microbial communities on the surface of DCGs have remained underexplored. Here, we investigated bacterial and fungal diversity and co-occurrence networks on the supraglacial debris habitat of two DCGs (Hailuogou and Dagongba Glaciers) in the southeastern Tibetan Plateau. We found that the supraglacial debris harbored abundant microbes with Proteobacteria occupying more than half (51.5%) of the total bacteria operational taxonomic units. The composition, diversity, and co-occurrence networks of both bacterial and fungal communities in the debris were significantly different between Hailuogou Glacier and Dagongba Glacier even though the glaciers are geographically adjacent within the same mountain range. Bacteria were more diverse in the debris of the Dagongba Glacier, where a lower surface velocity and thicker debris layer allowed the supraglacial debris to continuously weather and accumulate nutrients. Fungi were more diverse in the debris of the Hailuogou Glacier, which experiences a wetter monsoonal climate, is richer in calcium, has greater debris instability, and greater ice velocity than the Dagongba Glacier. These factors may provide ideal conditions for the dispersal and propagation of fungi spores on the Hailuogou Glacier. In addition, we found an obvious gradient of bacterial diversity along the supraglacial debris transect on the Hailuogou Glacier. Bacterial diversity was lower where debris cover was thin and scattered and became more diverse near the glacial terminus in thick, slow-moving debris. No such increasing bacterial pattern was detected on the Dagongba Glacier, which implies a positive relationship of debris age, thickness, and weathering on bacterial diversity. Additionally, a highly connected bacterial co-occurrence network with low modularity was found in the debris of the Hailuogou Glacier. In contrast, debris from the Dagongba Glacier exhibited less connected but more modularized co-occurrence networks of both bacterial and fungal communities. These findings indicate that less disturbed supraglacial debris conditions are crucial for microbes to form stable communities on DCGs.

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The search for extant microbial life will be a major focus of future astrobiology missions; however, no direct extant life detection instrumentation is included in current missions to Mars. In this study, we developed the semiautomated MicroLife detection platform that collects and processes environmental samples, detects biosignatures, and characterizes microbial activity. This platform is composed of a drill for sample collection, a redox dye colorimetric system for microbial metabolic activity detection and assessment (µMAMA [microfluidics Microbial Activity MicroAssay]), and a MinION sequencer for biosignature detection and characterization of microbial communities. The MicroLife platform was field-tested on White Glacier on Axel Heiberg Island in the Canadian high Arctic, with two extracted ice cores. The µMAMA successfully detected microbial metabolism from the ice cores within 1 day of incubation. The MinION sequencing of the ice cores and the positive µMAMA card identified a microbial community consistent with cold and oligotrophic environments. Furthermore, isolation and identification of microbial isolates from the µMAMA card corroborated the MinION sequencing. Together, these analyses support the MicroLife platform's efficacy in identifying microbes natively present in cryoenvironments and detecting their metabolic activity. Given our MicroLife platform's size and low energy requirements, it could be incorporated into a future landed platform or rovers for life detection.

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Microplastics are an emerging and persistent pollutant due to their threat to global ecological systems and human health. Recent studies showed that microplastics have infiltrated the remote Third Pole - the Tibetan Plateau. Here, we summarize the current evidence for microplastic pollution in the different environments (rivers/lakes, sediment, soil, ice/snow and atmosphere) of the Tibetan Plateau. We assess the spatial distribution, source, fate, and potential ecological effects of microplastics in this broad plateau. The integrated results show that microplastics were pervasive in biotic and abiotic components of the Tibetan Plateau, even at the global highest-altitude, Mt. Everest. Although the concentration of microplastics in the Tibetan Plateau was far below that found in the densely populated lowlands, it showed a higher concentration than that in the ocean system. Tourist populations are identified as a substantial source of anthropogenic plastic input rather than local residents due to the rapid development of the tourism industry. In the sparsely inhabited remote area of the Tibetan Plateau, long-range atmospheric transport facilitates allochthonous microplastic diffusion. Robust solar radiation in the Tibetan Plateau might enhanced production of secondary microplastics by weathering (UV-photooxidation) of abandoned plastic waste. A rough estimation showed that the microplastic export flux from melting glaciers was higher than that measured in most of the world's largest rivers, which affects local and downstream areas. Since the Tibetan Plateau is vital for Asian water supply and numerous endangered wildlife, the potential human and ecological risk of microplastics to these fragile ecosystems needs to be fully evaluated within the context of climate-change impacts.

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Rock glaciers are relatively common in Antarctic permafrost areas and could be considered postglacial cryogenic landforms. Although the extensive presence of rock glaciers, their chemical-physical and biotic composition remain scarce. Chemical-physical parameters and fungal community (by sequencing the ITS2 rDNA, Illumina MiSeq) parameters of a permafrost core were studied. The permafrost core, reaching a depth of 6.10 m, was divided into five units based on ice content. The five units (U1-U5) of the permafrost core exhibited several significant (p < 0.05) differences in terms of chemical and physical characteristics, and significant (p < 0.05) higher values of Ca, K, Li, Mg, Mn, S, and Sr were found in U5. Yeasts dominated on filamentous fungi in all the units of the permafrost core; additionally, Ascomycota was the prevalent phylum among filamentous forms, while Basidiomycota was the dominant phylum among yeasts. Surprisingly, in U5 the amplicon sequence variants (ASVs) assigned to the yeast genus Glaciozyma represented about two-thirds of the total reads. This result may be considered extremely rare in Antarctic yeast diversity, especially in permafrost habitats. Based on of the chemical-physical composition of the units, the dominance of Glaciozyma in the deepest unit was correlated with the elemental composition of the core.

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Rock glaciers are the most prominent permafrost-related mountain landforms. This study investigates the effects of the discharge from an intact rock glacier on the hydrological, thermal and chemical dynamics of a high-elevation stream in the NW Italian Alps. Despite draining only 39 % of the watershed area, the rock glacier sourced a disproportionately large amount of discharge to the stream, with the highest relative contribution to the catchment streamflow occurring in late summer - early autumn (up to 63 %). However, ice melt was estimated to be only a minor component to the discharge of the rock glacier, due to its insulating coarse debris mantle. The sedimentological characteristics and internal hydrological system of the rock glacier played a major role in its capability to store and transmit relevant amounts of groundwater, especially during the baseflow periods. Besides the hydrological influence, the cold and solute-enriched discharge from the rock glacier significantly lowered the stream water temperature (especially during warm atmospheric periods) as well as increased the concentrations of most solutes in the stream. Furthermore, in the two lobes forming the rock glacier, different internal hydrological systems and flowpaths, likely driven by different permafrost and ice content, caused contrasting hydrological and chemical behaviours. Indeed, higher hydrological contributions and significant seasonal trends in solute concentrations were found in the lobe with higher permafrost and ice content. Our results highlight the relevance of rock glaciers as water resources, despite the minor ice melt contribution, also suggesting their potential, increasing hydrological importance in the light of climate warming.

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Microplastics have been reported from various ecosystems including lakes, ponds, wetlands, mountains, and forests globally. Recent research works showed microplastic deposition and accumulation in the Himalayan mountains and adjoining ecosystems, rivers and streams. Fine particles of microplastic originating from different anthropogenic sources can travel long distances, even upwards (altitudinally) through atmospheric transport and can pollute remote and pristine locations situated in the Himalayas. Precipitation also plays a vital role in influencing deposition and fallout of microplastics in the Himalayas. Microplastics can be trapped in the snow in glaciers for a long time and can be released into freshwater rivers by snow melting. Microplastic pollution in Himalayan rivers such as the Ganga, Indus, Brahmaputra, Alaknanda, and Kosi has been researched on both the upper and lower catchments. Additionally, Himalayan region draws many domestic and international tourists throughout the year, resulting in generation of massive and unmanageable volume of plastics wastes and finally ending up in the open landscapes covering forests, river streams and valley. Fragmentation of these plastic wastes can lead to microplastic formation and accumulation in the Himalayas. This paper discusses and explains occurrence and distribution of microplastics in the Himalayan landscapes, possible adverse effects of microplastic on local ecosystems and human population and policy intervention needed to mitigate microplastic pollution in the Himalayas. A knowledge gap was noticed regarding the fate of microplastics in the freshwater ecosystems and their control mechanisms in the Indian Himalayas. Regulatory approaches for microplastics management in the Himalayas sit within the broader plastics/solid waste management and can be implemented effectively by following integrated approaches.