Heterogeneous characteristics and absorption enhancement of refractory black carbon in an urban city of China.

In this study, field measurement was conducted using an integrated online monitoring system to characterize heterogeneous properties and light absorption of refractory black carbon (rBC). rBC particles are mainly from the incomplete combustion of carbonaceous fuels. With the data collected from a single particle soot photometer, thickly coated (BC) and thinly coated (BC) particles are characterized with their lag times.

Apparent fractionation of hydrogen isotope from precipitation to leaf wax n-alkanes from natural environments and manipulation experiments.

Knowledge of hydrogen isotopic fractionation (ε) of plant leaf waxes is the foundation for applying hydrogen isotope values (δH) in environmental reconstructions. In this work, we systematically investigated plant ε values (ε, ε, ε and ε, representing the isotopic fractionation between plant n-alkane δH and precipitation δH, soil water δH, leaf water δH and lake water δH) from the natural environments and manipulation experiments. The results show that the ε values of terrestrial plants have large variations (from -190 ‰ to -20 ‰) and become more negative with increasing aridity index.

Nitrogen removal in improved subsurface wastewater infiltration system: Mechanism, microbial indicators and the limitation of phosphorus.

To enhance the nitrogen removal capacity, scrap iron filings and Si-Al porous clay mineral material (PCMW) was used to improve a subsurface wastewater infiltration system (SWIS). The results showed TN and NH-N removal efficiencies of improved SWIS were 20.72% and 5.

A carbon-neutrality-capactiy index for evaluating carbon sink contributions.

The accurate determination of the carbon-neutrality capacity (CNC) of a region is crucial for developing policies related to emissions and climate change. However, a systematic diagnostic method for determining the CNC that considers the rock chemical weathering carbon sink (RCS) is lacking. Moreover, it is challenging but indispensable to establish a fast and practical index model to determine the CNC.

Coal-source acid mine drainage reduced the soil multidrug-dominated antibiotic resistome but increased the heavy metal(loid) resistome and energy production-related metabolism.

A recent global scale study found that mining-impacted environments have multi-antibiotic resistance gene (ARG)-dominated resistomes with an abundance similar to urban sewage but much higher than freshwater sediment. These findings raised concern that mining may increase the risk of ARG environmental proliferation. The current study assessed how typical multimetal(loid)-enriched coal-source acid mine drainage (AMD) contamination affects soil resistomes by comparing with background soils unaffected by AMD.

Weakening of the South Asian summer monsoon linked to interhemispheric ice-sheet growth since 12 Ma.

The evolution and driving mechanism of the South Asian summer monsoon (SASM) are still poorly understood. We here present a 12-Myr long SASM record by analyzing the strontium and neodymium isotopic composition of detrital components at IODP Exp. 359 Site U1467 from the northern Indian Ocean.

High time-resolution source apportionment and health risk assessment for PM-bound elements at an industrial city in northwest China.

To better respond to heavy air pollution, the local government of Baoji City, a traditionally industry dominated city in northwest China, released several warning levels between December 2019 and January 2020. The system aims to provide a more efficient control of pollution sources. In this study, a high-time resolution measurement of PM-bound elements was applied to capture the diurnal-scale dynamic processes associated with major pollution activities in northwest China.

Metagenomic analysis characterizes resistomes of an acidic, multimetal(loid)-enriched coal source mine drainage treatment system.

Heavy metal(loid) contaminations caused by mine activities are potential hot spots of antibiotic resistance genes (ARGs) because of heavy metal(loid)-induced co-selection of ARGs and heavy metal(loid) resistance genes (MRGs). This study used high-throughput metagenomic sequencing to analyze the resistome characteristics of a coal source acid mine drainage passive treatment system. The multidrug efflux mechanism dominated the antibiotic resistome, and a highly diverse heavy metal(loid) resistome was dominated by mercury-, iron-, and arsenic--associated resistance.

Enhanced weathering input from South Asia to the Indian Ocean since the late Eocene.

Enhanced silicate weathering induced by the uplift of the Himalayan-Tibetan Plateau (HTP) has been considered as the major cause of pCO decline and Cenozoic cooling. However, this hypothesis remains to be validated, largely due to the lack of a reliable reconstruction of the HTP weathering flux. Here, we present a 37-million-year record of the difference in the seawater radiogenic neodymium isotopic composition (Δε) of Ocean Drilling Program (ODP) sites and Fe-Mn crusts between the northern and central Indian Ocean, which indicates the contribution of regional weathering input from the South Asian continent to the Indian Ocean.

Anthropogenic activity and millennial climate variability affect Holocene mercury deposition of an alpine wetland near the largest mercury mine in China.

Mercury (Hg) is a potentially toxic element that can be transported globally through the atmosphere, once deposited in the environment, has strong bioaccumulation and extreme toxicity in food webs, especially in wetland ecosystems. Anthropogenic Hg emissions have enhanced Hg deposition by 3-5 times since the industrial revolution, and the mining and smelting of Hg ore are important emission sources. However, the dynamics in Hg deposition around the largest Hg mine in China before the industrial revolution and their driving forces remain poorly explored.

A satellite-driven model to estimate long-term particulate sulfate levels and attributable mortality burden in China.

Ambient fine particulate matter (PM) pollution is a major environmental and public health challenge in China. In the recent decade, the PM level has decreased mainly driven by reductions in particulate sulfate as a result of large-scale desulfurization efforts in coal-fired power plants and industrial facilities. Emerging evidence also points to the differential toxicity of particulate sulfate affecting human health.

Anthropogenic sulfate aerosol pollution in South and East Asia induces increased summer precipitation over arid Central Asia.

Precipitation has increased across the arid Central Asia region over recent decades. However, the underlying mechanisms of this trend are poorly understood. Here, we analyze multi-model simulations from the Precipitation Driver and Response Model Intercomparison Project (PDRMIP) to investigate potential drivers of the observed precipitation trend.

Ancient Great Wall building materials reveal environmental changes associated with oases in northwestern China.

Plant materials used in the construction of segments and beacon towers of the ancient Great Wall in northwestern China contain untapped potential for revealing local paleoclimatic and environmental conditions. For the first time, we characterize the molecular preservation and stable carbon and nitrogen isotope compositions of AMS-dated common reeds (Phragmites) collected from ancient Great Wall fascines in today's Gansu and Xinjiang using a combination of chromatographic techniques and isotope analyses. Our molecular data, along with Scanning Electron Microscopy, demonstrate excellent preservation of these ancient reeds, which were harvested from nearby habitats during periods of significant expansion of Imperial China when climate conditions sustained sizeable oases in the region.

Earthworms regulate plants' effects on soil microbial nutrient limitations: Examinations with contrasting soils and moisture.

Soil microbial nutrient limitations significantly affect microbial processes and thus ecosystem functionality, whereas the response of soil microbial nutrient limitations to earthworms has rarely been addressed but is urgently needed due to the important role of earthworms in terrestrial ecosystems. By examining how earthworms regulate plants' effects on microbial nutrient limitations under contrasting soil types and moisture conditions, we showed that plant presence reduced microbial carbon (C) limitation and such reduction was enhanced by earthworm. Plant presence increased soil microbial phosphorus (P) limitation in soils with earthworms in most cases.

Exceptional terrestrial warmth around 4200-2800 years ago in Northwest China.

One of the Holocene abrupt events around 4200 years ago, lasting for ∼ 200 years, is thought to have caused cultural disruptions, yet terrestrial climatic status right after the cold/dry event remains poorly defined and is often presumed that a generally cool condition prevailed during the Bronze Age (∼ 4000-2200 years ago). Here we report an alkenone-based summer temperature record over the past ∼ 12,000 years, in addition to two updated alkenone records, from Northwest China, providing new insights into the climatic status right after the event. Our results indicate that exceptional terrestrial warmth, up to ∼ 6 °C, occurred around 4200-2800 years ago during the Bronze Age, superimposed on the long-term Holocene cooling trend.

Staggered-peak production is a mixed blessing in the control of particulate matter pollution.

Staggered-peak production (SP)-a measure to halt industrial production in the heating season-has been implemented in North China Plain to alleviate air pollution. We compared the variations of PM composition in Beijing during the SP period in the 2016 heating season (SP) with those in the normal production (NP) periods during the 2015 heating season (NP) and 2016 non-heating season (NP) to investigate the effectiveness of SP. The PM mass concentration decreased from 70.

Direct emissions of particulate glyoxal and methylglyoxal from biomass burning and coal combustion.

Glyoxal (Gly) and methylglyoxal (Mgly) are key precursors globally for secondary organic aerosol (SOA) formation. These two species were often thought to be formed in the atmosphere via photochemical oxidation of organics from biogenic and anthropogenic origins, although few studies have shown their direct emissions. In this study, we report direct emissions of particulate Gly and Mgly from different residential fuels typically used in north China.

Evaluating the accuracy and reliability of compound-specific carbon isotopic analysis using gas chromatography-combustion-isotope ratio mass spectrometry with the addition of a reduction furnace.

Rationale: Gas chromatography-combustion-isotope ratio mass spectrometry (GC/C/IRMS) is widely used for compound-specific carbon isotopic analysis. However, current isotopic analysis systems utilize the GC IsoLink combustion reactor, and independent reduction furnaces are not implemented. Therefore, whether this limitation in furnace use affects the precision of compound-specific carbon isotopic analysis needs to be evaluated.

Distribution Characteristics and Influencing Factors of Bio-elements in the Human Hair of Uyghur Communities in an Oasis Area of Xinjiang, China.

Located in central Asia, Xinjiang is characterized as a diverse environment in China, consisting of vast deserts, dotted oases, and high mountains. Due to the combined effect of climate conditions under such a diverse environment, there are large differences in human activities, living styles, and eating habits in farmland and grazing pastures between Xinjiang and other regions of China. This study aimed to investigate the variations and mechanisms of elemental distribution in the hair of Uyghur communities among different ages and genders and under different land use backgrounds in an oasis region in Xinjiang.

Deciphering factors driving soil microbial life-history strategies in restored grasslands.

In macroecology, the concept of r- and K-strategy has been widely applied, yet, there have been limited studies on microbial life-history strategies in temperate grasslands using multiple sequencing approaches. Total phospholipid fatty acid (PLFA) analysis, high-throughput meta-genomic sequencing, and GeoChip technologies were used to examine the changes in microbial life-history traits in a chronosequence of restored grasslands (1, 5, 10, 15, 25, and 30 years since restoration). Grassland restoration increased the relative abundances of Actinobacteria, Proteobacteria, and Bacteroidetes but reduced the relative abundances of Acidobacteria, Planctomycetes, and Chloroflexi.

Variations of the urban PM chemical components and corresponding light extinction for three heating seasons in the Guanzhong Plain, China.

In order to investigate the variations of PM (particulate matter with an aerodynamic diameter less than 2.5 μm) chemical components responding to the pollution control strategy and their effect on light extinction (b) in the Guanzhong Plain (GZP), the comparisons of urban atmospheric chemical components during the heating seasons were extensively conducted for three years. The average concentration of PM decreased significantly from 117.

Synergistic interplay between Azospirillum brasilense and exogenous signaling molecule HS promotes Cd stress resistance and growth in pak choi (Brassica chinensis L.).

Inoculation with growth-promoting rhizobacteria inoculation and the addition of exogenous signaling molecules are two distinct strategies for improving heavy metal resistance and promoting growth in crops through several mechanisms. However, whether rhizobacteria and phyllosphere signaling molecules can act synergistically alleviate heavy metal stress and promote growth and the mechanisms underlying these effects remain unclear. Here, a novel strategy involving the co-application of growth-promoting rhizobacteria and an exogenous signaling molecule was developed to reduce cadmium (Cd) phytotoxicity and promote pak choi growth in Cd-contaminated soil.

Maximum July-August temperatures for the middle of the southern Tien Shan inferred from tree-ring latewood maximum densities.

Long-term temperature reconstructions are urgently needed to prolong meteorological climatic data, which are too short to evaluate the anthropogenic effect on climate change since the Industrial Revolution. The maximum latewood chronology (MXD) of Picea schrenkiana in the middle of the southern Tien Shan was established, and it showed a strong correlation with the mean maximum temperature of the current July to August (T), with r = 0.773 (p < 0.

[Characteristics and factors influencing organic carbon decomposition in sediment in check dams].

More than 56000 check dams have been built in the Loess Plateau, which capture around 0.95 Pg of organic carbon and act as an important carbon sink. However, the decomposition mechanism of organic carbon in the sediment in these dams is still poorly understood, and thus it is difficult to quantify their role in terrestrial carbon cycling.

Urgency of controlling agricultural nitrogen sources to alleviate summertime air pollution in the North China Plain.

Agricultural nitrogen sources (ANS) have played an increasingly important role in the air quality since ANS emission controls are much weaker than those for fossil fuel combustion sources due to the increasing food demand. However, ANS emissions are highly uncertain due to stochastic agricultural management activities and limited field measurements, and impacts of ANS on the air quality remain elusive. In the study, the WRF-Chem model has been used to investigate ANS shares in near surface air pollutant concentrations during a growing season in the North China Plain (NCP), with ANS emissions constrained by satellite retrievals.