Lakes are sources of atmospheric carbon dioxide (CO), contributing to global climate change. Temporal variations in lake CO emissions are pronounced, with algal growth and precipitation identified as important drivers. Eutrophic lakes often act as atmospheric CO sinks during the growing season.
View Article and Find Full Text PDFClimate warming has accelerated glacier melting, releasing legacy pollutants such as mercury (Hg) into aquatic ecosystems. While the relationship between Hg in glacier meltwater runoff, total suspended particles (TSP), and runoff discharges has been established, the underlying inter-relationships and governing factors remain poorly understood. To address this knowledge gap, we conducted a continuous fixed-point sampling at Laohugou No.
View Article and Find Full Text PDFA field survey was conducted in the central Tibetan Plateau (Nam Co) in China for high-time resolution measurements of gaseous elemental mercury (GEM), gaseous oxidized mercury (GOM), and particle-bound mercury (PBM). Average concentrations (± 1 SD) of GEM, PBM, and GOM from November 2014 to March 2015 were 1.11 ± 0.
View Article and Find Full Text PDFQuantification mercury (Hg) pools in forests is crucial for understanding the Hg assimilation, flux and even biogeochemical cycle in forest ecosystems. While several investigations focused on Hg pools among broad-leaved, coniferous and mixed forests, there was still absent information on alpine forest. We sampled soil, moss and various tissues of the dominant Qinghai spruce (Picea crassifolia Kom.
View Article and Find Full Text PDFThe transboundary mercury (Hg) pollution has caused adverse effects on fragile ecosystems of the Tibetan Plateau (TP). Yet, knowledge of transport paths and source regions of atmospheric Hg on the inland TP remains poor. Continuous measurements of atmospheric total gaseous mercury (TGM) were conducted in the central TP (Tanggula station, 5100 m a.
View Article and Find Full Text PDFMountain glaciers are essential for supplying water resources that sustain downstream communities and livelihoods, yet the hydrogeochemical dynamics at glacier terminals and the impact of glacier retreat on downstream water chemistry are not fully understood. This study addresses this by conducting comprehensive observations and analysis of water chemistry at refined spatial and temporal resolutions in the Lhasa River Valley Glacier No. 1 (LRVG-1) catchment, a vital source of drinking and irrigation water for the local population on the Tibetan Plateau.
View Article and Find Full Text PDFAtmospheric pollution has detrimental effects on human health and ecosystems. The southern region of the Himalayas, undergoing rapid urbanization and intense human activities, faces poor air quality marked by high aerosol loadings. In this study, we conducted a two-year PM sampling in the suburban area (Godavari) of Kathmandu, a representative metropolis situated in the southern part of the central Himalayas.
View Article and Find Full Text PDFGlacier melting exports a large amount of nitrate to downstream aquatic ecosystems. Glacial lakes and glacier-fed rivers in proglacial environments serve as primary recipients and distributors of glacier-derived nitrate (NO), yet little is known regarding the sources and cycling of nitrate in these water bodies. To address this knowledge gap, we conducted a comprehensive analysis of nitrate isotopes (δN, δO, and ΔO) in waters from the glacial lake and river of the Rongbuk Glacier-fed Basin (RGB) in the mountain Everest region.
View Article and Find Full Text PDFThaw slumps can lead to considerable carbon loss in permafrost regions, while the loss of components from two major origins, i.e., microbial and plant-derived carbon, during this process remains poorly understood.
View Article and Find Full Text PDFMercury (Hg) released by melting glaciers is likely to bind to suspended particles in meltwater runoff, posing potential risks to downstream ecosystems. The rapidly receding glaciers on the Tibetan Plateau promote the export of total suspended particles (TSP), increasing the uncertainty of Hg export released by glacier melting. To investigate the relationships between TSP and Hg, a multimedia sampling campaign was conducted in July 2020 in the Kuoqionggangri glacier region of the Lhasa River Valley No.
View Article and Find Full Text PDFAs the Third Pole of the world, the Tibetan Plateau (TP) is sensitive to anthropogenic influences. Biomass combustion is one of the most important anthropogenic sources of mercury (Hg) emissions in the TP. However, due to the lack of knowledge about Hg emission characteristics and activity levels in the plateau, atmospheric Hg emissions from biomass combustion in the TP are under large uncertainties.
View Article and Find Full Text PDFGlob Chang Biol
November 2022
Warming is known to reduce soil carbon (C) stocks by promoting microbial respiration, which is associated with the decomposition of microbial residue carbon (MRC). However, the relative contribution of MRC to soil organic carbon (SOC) across temperature gradients is poorly understood. Here, we investigated the contribution of MRC to SOC along two independent elevation gradients of our model system (i.
View Article and Find Full Text PDFInvestigation of mercury (Hg) from atmospheric precipitation is important for evaluating its ecological impacts and developing mitigation strategies. Western China, which includes the Tibetan Plateau and the Xinjiang Uyghur Autonomous Region, is one of the most remote region in the world and is understudied in regards to Hg precipitation. Here we report seesaw-like patterns in spatial variations of precipitation Hg in Western China, based on Hg speciation measurements at nine stations over this remote region.
View Article and Find Full Text PDFGlaciers in the Himalayan region have been receding rapidly in recent decades, drawing increasing concerns about the release of legacy pollutants (e.g., mercury (Hg)).
View Article and Find Full Text PDFAs an important component of carbonaceous aerosols (CA), organic carbon (OC) exerts a strong, yet insufficiently constrained perturbation of the climate. In this study, we reported sources of OC based on its natural abundance radiocarbon (C) fingerprinting in aerosols and water-insoluble organic carbon (WIOC) in snowpits across the Tibetan Plateau (TP) - one of the remote regions in the world and a freshwater reservoir for billions of people. Overall, the proportions from C-based non-fossil fuel contribution (f) for OC in aerosols was 74 ± 10%, while for WIOC in snowpits was 81 ± 10%, both of which were significantly higher than that of elemental carbon (EC).
View Article and Find Full Text PDFIdentifying the drivers of the response of soil microbial respiration to warming is integral to accurately forecasting the carbon-climate feedbacks in terrestrial ecosystems. Microorganisms are the fundamental drivers of soil microbial respiration and its response to warming; however, the specific microbial communities and properties involved in the process remain largely undetermined. Here, we identified the associations between microbial community and temperature sensitivity (Q) of soil microbial respiration in alpine forests along an altitudinal gradient (from 2974 to 3558 m) from the climate-sensitive Tibetan Plateau.
View Article and Find Full Text PDFDeposition of atmospheric mercury (Hg) is the most important Hg source on the high-altitude Himalayas and Tibetan Plateau. Herein, total gaseous Hg (TGM) at an urban and a forest site on the Tibetan Plateau was collected respectively from May 2017 to October 2018, and isotopic compositions were measured to clarify the influences of landforms and monsoons on the transboundary transport of atmospheric Hg to the Tibetan Plateau. The transboundary transported anthropogenic emissions mainly originated over Indo-Gangetic Plain and carried over the Himalayas by convective storms and mid-tropospheric circulation, contributing over 50% to the TGM at the Lhasa urban site, based on the binary mixing model of isotopes.
View Article and Find Full Text PDFTrait-based approaches provide a candidate framework for linking soil microbial community to ecosystem processes, yet how the trade-offs in different microbial traits regulate the community-level metabolic efficiency remains unknown. Herein we assessed the roles of the microbial taxa with particular trait strategies in mediating soil microbial metabolic efficiency along an altitude gradient on the Tibetan Plateau. Results showed that soil microbial metabolic efficiency declined with increasing altitude, as indicated by the increasing metabolic quotient (microbial respiration per unit biomass, qCO) and decreasing carbon use efficiency (CUE).
View Article and Find Full Text PDFGlobally, the consumption of coastal fish is the predominant source of human exposure to methylmercury, a potent neurotoxicant that poses health risks to humans. However, the relative importance of riverine inputs and atmospheric deposition of mercury into coastal oceans remains uncertain owing to a lack of riverine mercury observations. Here, we present comprehensive seasonal observations of riverine mercury and methylmercury loads, including dissolved and particulate phases, to East Asia's coastal oceans, which supply nearly half of the world's seafood products.
View Article and Find Full Text PDFInformation about the long-term trends of wet mercury (Hg) deposition is important for assessing the impact of atmospheric pollution on environmental health. As the most populated and capital city of Tibet, Lhasa is isolated far away from the heavily-polluted urban clusters in China. In this study, a 10-year observation was conducted in Lhasa to establish the long-term trend of wet Hg deposition and investigate the possible causes of this variation trend.
View Article and Find Full Text PDFTo understand the characteristics of particulate matter (PM) and other air pollutants in Xinjiang, a region with one of the largest sand-shifting deserts in the world and significant natural dust emissions, the concentrations of six air pollutants monitored in 16 cities were analyzed for the period January 2013-June 2019. The annual mean PM, PM, SO, NO, CO, and O concentrations ranged from 51.44 to 59.
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