Investigating the migration and transformation of carbonaceous and nitrogenous matter in the cryosphere areas is crucial for understanding global biogeochemical cycle and earth's climate system. However, water-soluble organic constituents and their transformation in multiple water bodies are barely investigated. Water-soluble organic carbon (WSOC) and organic nitrogen (WSON), and particulate black carbon (PBC) in multiple types of water bodies in eastern Tibetan Plateau (TP) cryosphere for the first time have been systematically investigated. Statistical results exhibited that from south to north and from east to west of this region, WSOC concentrations in alpine river runoff were gradually elevated. WSOC and nitrogenous matter in the alpine river runoff and precipitation in the glacier region presented distinct seasonal variations. WSON was the dominant component (63.4%) of water-soluble total nitrogen in precipitation over high-altitude southeastern TP cryosphere. Water-soluble carbonaceous matter dominated the carbon cycle in the TP cryosphere, but particulate carbonaceous matter in the alpine river runoff had a small fraction of the cryospheric carbon cycle. Analysis of optical properties illustrated that PBC had a much stronger light absorption ability (MAC-PBC: 2.28 ± 0.37 m² g⁻¹) than WSOC in the alpine river runoff (0.41 ± 0.26 m² g⁻¹). Ionic composition was dominated by SO₄²⁻, NO₃⁻, and NH₄⁺ (average: 45.13 ± 3.75%) in the snow of glaciers, implying important contribution of (fossil fuel) combustion sources over this region. The results of this study have essential implications for understanding the carbon and nitrogen cycles in high altitude cryosphere regions of the world. Future work should be performed based on more robust in-situ observations and measurements from multiple environmental medium over the cryosphere areas, to ensure ecological protection and high-quality development of the high mountain Asia.

Microplastics are continuously released into the terrestrial environment from sources where they are used and produced. These microplastics accumulate in soils, sediments, and freshwater bodies, and some are conveyed via wind and water to the oceans. The concentration gradient between terrestrial inland and coastal regions, the factors that influence the concentration, and the fundamental transport processes that could dynamically affect the distribution of microplastics are unclear. We analyzed microplastic concentration reported in 196 studies from 49 countries or territories from all continents and found that microplastic concentrations in soils or sediments and surface water could vary by up to eight orders of magnitude. Mean microplastic concentrations in inland locations such as glacier (191 n L⁻¹) and urban stormwater (55 n L⁻¹) were up to two orders of magnitude greater than the concentrations in rivers (0.63 n L⁻¹) that convey microplastics from inland locations to water bodies in terrestrial boundary such as estuaries (0.15 n L⁻¹). However, only 20% of studies reported microplastics below 20 μm, indicating the concentration in these systems can change with the improvement of microplastic detection technology. Analysis of data from laboratory studies reveals that biodegradation can also reduce the concentration and size of deposited microplastics in the terrestrial environment. Fiber percentage was higher in the sediments in the coastal areas than the sediments in inland water bodies, indicating fibers are preferentially transported to the terrestrial boundary. Finally, we provide theoretical frameworks to predict microplastics transport and identify potential hotspots where microplastics may accumulate.

Trace elements (TEs) in the insoluble particles of surface snow are less affected by melting processes and can be used as environmental proxies to reveal natural and anthropogenic emissions. Here the first comprehensive study of the 16 TEs (Al, As, Ba, Bi, Cr, Cu, Fe, Mn, Ni, Pb, Sn, Sr, Ti, U, V, and Zn) in insoluble particles (>0.45 μm) from surface snow samples collected at Urumqi Glacier No. 1 (UG1), Eastern Tien Shan, China, from February 2008 to January 2010 were presented. Results show that concentrations of most insoluble particulate TEs (TEs ᵢₙₛₒₗ) in the snow were higher in summer while lower in winter, due to the increasing particle inputs and melting processes. The abundances of As, Cr, Cu, Ni, Pb, and Zn in some samples were higher than those in surrounding urban soils, which might due to these TEs have further anthropogenic input beyond the already contaminated re-suspended urban soil particles and TEs were mainly enriched in particles with small grain size. Based on enrichment factor (EF) and principal component analysis (PCA), our results suggest that eight TEs (Al, Fe, Ti, Ba, Mn, Sr, U, and V) mainly came from mineral dust, while the remaining eight TEs (As, Bi, Cr, Cu, Ni, Pb, Sn, and Zn) were affected by coal combustion, mining and smelting of non-ferrous metals, traffic emissions, and the steel industry. The Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model suggests that pollutants might originate from Xinjiang province, Kazakhstan, and Kyrgyzstan. Moreover, UG1 received more significant inputs of particle-bound pollutants in summer than in winter due to the stronger convection and the prevailing valley wind that transports pollutants from the city of Urumqi.

This study employs the grain size distributions and the concentrations and isotopic compositions of Sr, Nd, and Pb in the precipitation samples collected from the Laohugou Glacier (LHG) in northeastern Tibetan Plateau (TP) during August 2014–2015 to investigate seasonal variability in the insoluble precipitation particle sources. Fine dust particle (0.57–27 μm) depositions dominated in autumn and winter, whereas both fine and coarse dust particle (27–100 μm) depositions were found in spring and summer. Furthermore, the concentrations of Sr, Nd, and Pb also varied seasonally—the highest and lowest Sr and Nd concentrations were recorded in spring and autumn, respectively, whereas the highest and lowest Pb concentrations were recorded in winter and summer, respectively. The Sr and Nd isotopes revealed that the dust in the winter precipitation originated predominately from the Taklimakan Desert and that in spring originated from the Badain Jaran and Qaidam deserts. The precipitation residues in summer were derived from a complex mixture of dust sources from the Gobi and other large deserts in northwest China. Autumn residues were predominately sourced from local soil near the LHG as well as from the Qaidam Basin and the northern TP surface soil. The Taklimakan, long suspected as a major source of long-range transported dust, was an insignificant contributor to the precipitation over LHG during spring, summer, and autumn. Further, the Pb isotopic ratios indicated a primary impact of anthropogenic pollutants for most part of the year (except spring). Meteorological data and the MODIS AOD model are in good agreement with the results from the analyses of the Sr, Nd, and Pb isotopes for the LHG particle source, and further clarify the source regions. Thus, this study thus provides new evidence on the seasonal variability of the sources of the residual particles in remote glaciers in Central Asia.

Contamination by plastic debris has been documented in most regions of the world, but their occurrence in high mountain areas has not been investigated to date. Here we present the first report of the occurrence and amount of microplastic in any terrestrial glacier environment. In the supraglacial debris of the Forni Glacier (Italian Alps), we observed the occurrence of (mean ± standard error) 74.4 ± 28.3 items kg⁻¹ of sediment (dry weight). This amount is within the range of variability of microplastic contamination observed in marine and coastal sediments in Europe. Most plastic items were made by polyesters, followed by polyamide, polyethylene and polypropylene. We estimated that the whole ablation area of Forni Glacier should host 131–162 million plastic items. Microplastic can be released directly into high elevation areas by human activities in the mountain or be transported by wind to high altitude. The occurrence of microplastic on Forni Glacier may be due to the gathering of debris coming from the large accumulation area into the relatively smaller ablation area of the glacier, as a consequence of its flow and melting.

Cryoconite is a dark, dusty aggregate of mineral particles, organic matter, and microorganisms transported by wind and deposited on glacier surfaces. It can accelerate glacier melting and alter glacier mass balances by reducing the surface albedo of glaciers. Biomass burning in the Tibetan Plateau, especially in the glacier cryoconites, is poorly understood. Retene, levoglucosan, mannosan and galactosan can be generated by the local fires or transported from the biomass burning regions over long distances. In the present study, we analyzed these four molecular markers in cryoconites of seven glaciers from the northern to southern Tibetan Plateau. The highest levels of levoglucosan and retene were found in cryoconites of the Yulong Snow Mountain and Tienshan glaciers with 171.4 ± 159.4 ng g⁻¹ and 47.0 ± 10.5 ng g⁻¹ dry weight (d.w.), respectively. The Muztag glacier in the central Tibetan Plateau contained the lowest levels of levoglucosan and retene with mean values of 59.8 ng g⁻¹ and 0.4 ± 0.1 ng g⁻¹ d.w., respectively. In addition, the vegetation changes and the ratios of levoglucosan to mannosan and retene indicate that combustion of conifers significantly contributes to biomass burning of the cryoconites in the Yulong Snow Mountain and Tienshan glacier. Conversely, biomass burning tracers in cryoconites of Dongkemadi, Yuzhufeng, Muztag, Qiyi and Laohugou glaciers are derived from the combustion of different types of biomass including softwood, hardwood and grass.

An ecosystem in a cold climate river basin is vulnerable to the effects of climate change affecting permafrost thaw and glacier retreat. We currently lack sufficient data and information if and how hydrological processes such as glacier retreat, snowmelt and freezing-thawing affect sediment and nutrient runoff and transport, as well as N₂O emissions in cold climate river basins. As such, we have implemented well-established, semi-empirical equations of nitrification and denitrification within the Soil and Water Assessment Tool (SWAT), which correlate the emissions with water, sediment and nutrients. We have tested this implementation to simulate emission dynamics at three sites on the Canadian prairies. We then regionalized the optimized parameters to a SWAT model of the Athabasca River Basin (ARB), Canada, calibrated and validated for streamflow, sediment and water quality. In the base period (1990–2005), agricultural areas (2662 gN/ha/yr) constituted emission hot-spots. The spring season in agricultural areas and summer season in forest areas, constituted emission hot-moments. We found that warmer conditions (+13% to +106%) would have a greater influence on emissions than wetter conditions (−19% to +13%), and that the combined effect of wetter and warmer conditions would be more offsetting than synergetic. Our results imply that the spatiotemporal variability of N₂O emissions will depend strongly on soil water changes caused by permafrost thaw. Early snow freshet leads to spatial variability of soil erosion and nutrient runoff, as well as increases of emissions in winter and decreases in spring. Our simulations suggest crop residue management may reduce emissions by 34%, but with the mixed results reported in the literature and the soil and hydrology problems associated with stover removal more research is necessary. This modelling tool can be used to refine bottom-up emission estimations at river basin scale, test plausible management scenarios, and assess climate change impacts including climate feedback.

The environment is one of the main reservoirs of antibiotic resistance genes (ARGs) but multidrug resistant (MDR) environmental isolates are barely characterised. As suggested by the name, Pedobacter species have been predominantly isolated from soils, but are also recovered from water (including drinking water), chilled food, fish, compost, sludge, glaciers and other extreme environments. The susceptibility phenotype of Pedobacter lusitanus NL19 (isolated from a deactivated uranium mine), its closely related species and the genus type strain were investigated. All strains are MDR bacteria, resistant to β-lactams, colistin, aminoglycosides and ciprofloxacin. Therefore, Pedobacter spp. are likely intrinsically resistant to β-lactams (including ertapenem) and to other three classes of antibiotics. 6%–8% of their total protein-encoding genes encode a diverse collection of putative ARGs, including β-lactamases. These enzymes are highly abundant in all the other Pedobacter strains with sequenced genomes, especially class C, class B3 and class A. LUS-1 and PLN-1 were further characterised in E. coli. LUS-1 is a class A β-lactamase and it conferred an increase in the MIC of cefotaxime, albeit very low. PLN-1 is a class B3 β-lactamase with carbapenemase activity, conferring resistance to ertapenem and a 66x and 16x increase in the MIC of imipenem and meropenem, respectively. PLN-1 also hydrolyses ampicillin, 1st and 3rd generation cephalosporins, and at a lower extent cephamycins and 4th generation cephalosporins. Therefore, Pedobacter spp. encode a large and diverse arsenal of resistance mechanisms that make them environmental superbugs.

Intense biomass burning (BB) events are widespread in tropical and subtropical Asia. However, the impact of BB aerosols on the Tibetan Plateau (TP), especially on Tibetan glaciers, is poorly understood. In this study, BB signals are revealed using the specific molecular tracer levoglucosan in snow and ice samples from different Tibetan glaciers. Tibetan glaciers mainly act as receptors of BB emissions from surrounding regions. Significant differences in levoglucosan concentrations in glacier samples collected from two slopes on the same mountain range indicate that high mountains can act as natural barriers to block the transport of smoke aerosols to the TP. Levoglucosan concentrations show a decreasing trend from west to east on glaciers impacted by the Indian summer monsoon on the southern edge of the TP, while the opposite pattern was observed on glaciers under the prevailing westerlies along the northern edge. The emission sources, the controlling climate system, as well as deposition and degradation during transport determined the spatial distribution regimes of levoglucosan concentration on Tibetan glaciers.

The Antarctic continent is among the most pristine regions; yet various organic contaminants have been measured there routinely. Air and snow samples were collected during the austral spring (October–November, 2010) along the western Antarctic Peninsula and analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) to assess the relative importance of long-range transport versus local primary or secondary emissions. Highest concentrations of PCBs, PBDEs and DDTs were observed in the glacier’s snow sample, highlighting the importance of melting glaciers as a possible secondary source of legacy pollutants to the Antarctic. In the atmosphere, contaminants were mainly found in the vapor phase (>65%). Hexachlorobenzene (33.6 pg/m3), PCBs (11.6 pg/m3), heptachlor (5.64 pg/m3), PBDEs (4.22 pg/m3) and cis-chlordane (2.43 pg/m3) were the most abundant contaminants. In contrast to other compounds, PBDEs seem to have originated from local sources, possibly the research station itself. Gas-particle partitioning for analytes were better predicted using the adsorption partitioning model than an octanol-based absorption approach. Diffusive flux calculations indicated that net deposition is the dominant pathway for PBDEs and chlordanes, whereas re-volatilization from snow (during melting or metamorphosis) was observed for PCBs and some OCPs.