The 'Grain for Green' (GFG) project is a key ecological restoration initiative in the Loess Plateau. The land use changes induced by GFG project have the potential to alter the spatial distribution of soil organic carbon (SOC), yet its impact on the lateral loss of SOC was not well understood or insufficiently quantified. This study was to develop a comprehensive framework using a coupled hydro-biological model (SWAT-DayCent) together with incorporating an empirical carbon enrichment coefficient for quantitatively assessing soil and SOC losses in a typical watershed in the Chinese Loess Plateau-the Weihe River Basin (WRB). The results revealed that the GFG project reduced cropland area from 58.64 × 103 km2 in 1995 to 54.55 × 103 km2 in 2020, while forest area expanded from 21.13 × 103 km2 in 1995 to 22.14 × 103 km2 in 2020. Grassland area initially declined from 50.20 × 103 km2 in 1995 to 49.62 × 103 km2 in 2000, before increasing to 51.39 × 103 km2 in 2020. Areas with high soil erosion and SOC loss in the basin are predominantly located in its western and southern regions, while low-value areas are mainly concentrated in the northern and central-eastern regions, exhibiting strong spatial heterogeneity. The GFG project significantly reduced the soil erosion and SOC loss in WRB, thereby enhancing regional soil carbon sequestration capacity. Compared to cropland-to-grassland conversion (CTG), the reduction in soil and SOC losses was more pronounced for cropland-to-forest conversion (CTF). Specifically, under the CTF program, soil erosion decreased from 1179.13 t km-2 yr-1 in the baseline period (1995, before GFG) to 15.24 t km-2 yr-1 (2015, about 99% reduction), and 98% reduction was found for SOC (from 10.29 t km-2 yr-1 to 0.22 t km-2 yr-1). For the CTG program, soil loss decreased by 76% (from 965.29 t km-2 yr-1 to 232.95 t km-2 yr-1), and SOC loss decreased by 74% (from 8.68 t km-2 yr-1 to 2.25 t km-2 yr-1). The findings of this study can be valuable for soil conservation and carbon sink management in the Loess Plateau, and the framework we developed can be potentially applicable in other areas.

Wildfires release large amounts of greenhouse gases into the atmosphere, exacerbating climate change and causing severe impacts on air quality and human health. In this study, based on a bottom-up approach and using satellite data, combined with emission factor and aboveground biomass data for different vegetation cover types (forest, shrub, grassland, and cropland), the dynamic changes in CO2 emissions from wildfires in China from 2001 to 2022 were analyzed. The results showed that between 2001 and 2022, the total CO2 emissions from wildfires in China were 937.7 Tg (522.6–1516.0 Tg, 1 Tg = 1012 g), with an annual average of 42.6 Tg (23.8–68.9 Tg). The CO2 emissions from cropland and forest fires were relatively high, accounting for 45 % and 46 % of the total, respectively. The yearly variation in CO2 emissions from forest and shrub fires showed a significant downward trend, while emissions from grassland fires remained relatively stable. In contrast, the CO2 emissions from cropland fires showed an upward trend, primarily in Northeast China. Hot spot analysis and geographically and temporally weighted regression (GTWR) models revealed significant spatial heterogeneity in emissions across vegetation types. Persistent hot spots of shrub and forest fires were located in Southwest and South China, while Northeast China experienced sporadic but extreme fire events. The GTWR model for shrub fire CO2 emissions exhibited the highest predictive performance (R2 = 0.87), and climatic factors (particularly temperature and humidity) were the main influencing factors. Notably, the recent rise in cropland fire CO2 emissions in Northeast China is closely linked to region-specific straw-burning policies. The research results provide valuable references for atmospheric transport models, regional fire management, and national carbon accounting frameworks in the context of climate change.

Understanding human-nature interactions is critical for predicting Earth system stability under intensifying anthropogenic pressures, but centennial- to decadal-scale geological archives to robust quantify these dynamics remain scarce. Here, we present high-resolution geochemical records from the Yellow Sea, revealing competing climate and anthropogenic controls on chemical weathering and fires in the Yellow River Basin (YRB) since 2.2 kyr ago. Silicate weathering intensity generally tracked climate oscillations until similar to 580 CE (Sui Dynasty), when agricultural intensification initiated progressive potassium depletion via preferential weathering of K-bearing minerals. Concurrently, black carbon (BC) records reveal fire regime shifts from climate-modulated biomass smouldering to more human-induced flaming of crop residues and coal, especially since similar to 1350 CE (Ming Dynasty). These anthropogenic signatures coincided with intensified heavy metal release and ecosystem degradation. Our findings demonstrate that advances in agriculture and energy technology not only gradually reduced human dependence on climate, but also amplified anthropogenic perturbations across Earth's surface systems. This historical analogue highlights the urgency of balancing human adaptation with sustainable practices to mitigate potential irreversible impacts in the future.

Studies revealed that the atmosphere is one of the important medias for the spread of microplastics (MPs). In this study, atmospheric MPs in fine particles (PM2.5) and total suspended particles (TSP) from Beijing, Guangzhou, and Xi'an were investigated. The average abundance of MPs ranged from 0.170 to 0.389 items/m(3) in Beijing, 0.041 to 0.321 items/m(3) in Guangzhou, and 0.085 to 0.279 items/m(3) in Xi'an, across both PM2.5 and TSP samples. The abundance of MPs was higher in summer than in winter in Beijing and Guangzhou, but was higher in winter than in summer in Xi'an. Fibers were the predominant shape and films were rarely detected. MPs were primarily <200 mu m in size. MPs colored black, red, yellow, blue, transparent, and black-and-white were quantified separately in both PM2.5 and TSP. The main polymer types of MPs were identified more than 20 varieties, such as polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), and polystyrene (PS). The potential sources of MPs in Beijing, Guangzhou, and Xi'an varied with seasonal changes. In addition, the EDI of MPs decreased with the age in both the1-18 and > 18 age groups, and the potential respiratory exposure risk of MPs to the human body should be of concern.

COPs (combustion organic carbons) are a type of pollutant generated during fuel combustion, and the rapid accumulation of COPs in lake environments poses a serious threat to watershed climate change and lake ecological security. Taihu was used as the study area, and the concentrations of char in the surface sediments of Taihu were significantly higher than those of soot, with average concentrations of 2.2 and 0.5 mg kg− 1 respectively. In combination with 137CS and 210Pb dating technologies, the historical concentrations of COPs in Taihu have been reconstructed for the past century. The concentrations of all COPs have increased rapidly since the reform and opening up and have remained stable since approximately 2003, which is closely related to China’s industrial economic development and legal measures for environmental protection. Combined with the source apportionment receptor model, the contribution amount of each pollution source to the COPs in the sediment of Taihu in the past century was quantified. In the past hundred years, biomass sources have made relatively stable contributions to COPs in the Taihu Lake sediments. With the rapid development of social economy, the amount of petroleum fossil fuel combustion has increased year by year, and the COPs contributions to the Taihu Lake sediments have also increased rapidly in the past 40 years, becoming the main source of COP.

Discrepancies among fire proxies have long hindered integrated reconstructions of prehistoric anthropogenic burning and its climatic feedbacks. We analyzed a 490-cm terrestrial sedimentary profile from Guangrao, Shandong Province (GR section; 4000-0 yr BP) within the East Asian monsoon domain. By integrating fecal stanols with black carbon, polycyclic aromatic hydrocarbons (PAHs), and paleoecological proxies, we reconstruct fire regime dynamics and human responses to monsoon variability over the past four millennia. Spectral analysis of char and 5-ring PAHs concentrations, combined with Redfit and Multi-Taper Method (MTM) analyses, delineates a three-phase evolution of anthropogenic fire regimes over the past 4000 years:(1) 4000-2500 yr BP (Yueshi Culture to Warring States), characterized by low-intensity smoldering with similar to 500-year quasi-periodicity linked to agricultural clearance; (2) 2500-300 yr BP (Warring States to late Ming-early Qing), dominated by high-intensity flaming with similar to 280-year quasi-periodicity associated with warfare-related burning; and (3) the past 300 years (Qing to present), marked by pervasive biomass burning under anthropogenic climate influence at centennial-to-decadal scales. Cross-Wavelet Transform (XWT) and Wavelet Transform Coherence (WTC) analyses indicate that the periodic changes in the fire regime are significantly correlated with the quasi-periods of the East Asian Summer Monsoon (EASM) at the centennial scale (similar to 500 years) and (similar to 200-300 years), respectively. XGBoost-SHAP analyses show that the contribution of anthropogenic burning to fire regimes has increased progressively over the past 4000 years, rising from similar to 23 % to more than 51 %. These shifts in fire regime periodicity were mainly governed by seasonal hydrothermal changes induced by the weakening of the EASM, together with increasing spatial heterogeneity in anthropogenic fire patterns. Concurrently, in the mid-to-late Holocene, the use of different biomass-burning practices by ancient human progressively altered the regional ecological landscape. Therefore, Over 4000 years, anthropogenic fire practices have both mirrored centennial-scale monsoon variability and reflected adaptive shifts in production systems and social structures. In the lower Yellow River, sustained land reclamation promoted persistent smoldering fires, leading to landscape fragmentation, ecological degradation, and marking a critical threshold in anthropogenic mediated climate transformation.

As a frequent extreme event under global climate change, drought significantly threatens the net primary productivity (NPP) of terrestrial ecosystems. Although numerous studies have reported drought-induced declines in NPP, the hydroclimatic mechanisms behind remain insufficiently understood. The strong interdependence among temperature, precipitation, and water availability has made it challenging to quantify their independent effects on vegetation productivity under drought stress. Here, we assessed basin-scale NPP responses to drought across mainland China from 1982 to 2018 and applied a ridge regression method to disentangle the individual impacts of multiple hydroclimatic drivers on NPP variability, which overcomes the limitations of conventional correlation-based analyses by accounting for multicollinearity, thereby allowing a more robust identification of the dominant controls on drought-induced NPP variations. Our results revealed pronounced spatial heterogeneity in NPP responses among major basins, with the strongest productivity losses in the Songliao River basin and the Yellow River basin (12.41 g & sdot;C & sdot;m-2 & sdot;yr-1 and 11.71 g & sdot;C & sdot;m-2 & sdot;yr-1, respectively). Ridge-derived coefficients indicated that water availability was the primary driver of NPP sensitivity to drought, and stronger wateravailability control was typically associated with greater NPP losses during drought in water-limited basins. By integrating basin-scale analysis with a multivariate attribution framework, this study isolated the hydroclimatic controls of vegetation productivity under drought. The findings can improve understanding of terrestrial carbon dynamics and be informative for enhancing drought resilience and optimizing water-carbon management strategies in terrestrial ecosystems.

Black carbon, an important component of atmospheric aerosols, has an impact on climate change. When deposited on snow and ice, it reduces surface albedo, accelerating melting and amplifying global warming. Here, we analyzed lake sediment records from China and found that existing bottom-up inventories underestimate black carbon emissions prior to the mid-twentieth century. We incorporated a black carbon emission enhancement scheme based on reconstructed historical biomass burning emissions into a numerical climate model to assess this underestimation. The simulations indicated that increased historical emissions enhanced spring and summer radiative effects north of 60°N, leading to regional surface warming and accelerated Arctic snowmelt. Although the response varies with the strength of emission enhancement, the findings suggested that historical BC emission biases could alter the simulated Arctic energy balance and climate evolution. These results highlight the need for improved constraints on historical BC emissions to better assess their climate impacts. Increases in historical black carbon emissions enhanced spring and summer radiative effects north of 60°N, leading to regional surface warming and accelerated Arctic snowmelt, suggests a study combining climate modeling with lake-sediment records from China.

Natural- and human-induced environmental changes lead to structure shifts in phytoplankton communities, impacting the resilience, functioning, and ecosystem services of lakes. Given the scarcity of long-term monitoring data, particularly in the tropical region, our understanding of phytoplankton communities (cyanobacteria and eukaryotic micro-algae) and their triggering factors remains limited over decadal scales. We determined whether shifts in phytoplankton community within Huguangyan Maar Lake, a tropical lake, are linked to climate warming and assessed whether the observed changes resemble those documented in temperate or arctic regions. We applied 23S rRNA gene metabarcoding to 43 sediment samples covering the past similar to 140 years, and explored how the phytoplankton community respond to multiple environmental stresses. Phytoplankton diversity exhibited a marked increase beginning in the 1940s, followed by a distinct decline in the 1980s. Notably, a significant shift in community composition emerged toward the late 1980s, characterized by a rise in the relative abundance of diatoms (Aulacoseiraceae) and a concurrent decrease in rhodophytes (Bangiaceae) and cyanobacteria (Synechococcaceae). This pattern contrasted sharply with trends observed in other lakes, where cyanobacteria have maintained dominance in recent decades.Through integrated application of Mantel tests and random forest multivariate modeling, nutrient loading emerged as the predominant driver of community restructuring outweighing climatic factors. Concurrently, anthropogenic combustion signatures, such as polycyclic aromatic hydrocarbons, demonstrated significant covariance with phytoplankton assemblage reconstructing. This study highlights the dual impact of anthropogenic nutrients input and pollutants on phytoplankton communities in tropical lakes and provides important implication for future pollution and nutrient control.

Spheroidal carbonaceous particles (SCPs) and fossil fuel-derived soot (FF soot) in sediments are valuable proxies for reconstructing industrial emissions and understanding the multi-scale impacts of anthropogenic forcing on Earth systems. However, a systematic comparison of their initial deposition timing, flux peaks, and temporal patterns across lacustrine sedimentary records remains poorly constrained, leading to significant gaps in the understanding of the underlying drivers of these sedimentary signals. This study compared sediment records of these proxies from two maar lakes, Sihailongwan in northeastern China and Huguangyan in southeastern China, revealing how their signals exhibit synchronous patterns on a global scale while demonstrating complex heterogeneity at the regional scale due to differences in geographical location, climate systems, and industrialization pathways. Results showed that both SCP and FF soot fluxes in Sihailongwan began to rise in the 1950s, reaching a peak during China's rapid industrialization. In contrast, Huguangyan exhibited increasing fluxes only after the 1980s, synchronous with accelerated economic development in southeastern coastal regions, and culminating around 2010 CE, thereby reflecting intensified industrial activity and urbanization in this area. Notably, in both sediment records, the SCP peak occurred systematically earlier than the FF soot peak. This temporal offset likely reflects their representation of different industrialization phases and emission sources: SCPs derive mainly from industrial coal combustion, which peaked earlier, whereas FF soot also incorporates emissions from transportation fuels that rose later. Thus, these differences highlight the spatiotemporal evolution of energy structures and pollutant types throughout China's industrialization, especially those associated with black carbon. These findings offer important insights for selecting appropriate indicators to define the onset of the mid-20th century Anthropocene at varying spatial scales, and enhance our understanding of anthropogenic impacts from a micro-particle perspective.

Understanding the long-term interplay between air pollution and socioeconomic development is essential for evaluating sustainability transitions, yet its long-term dynamics remain poorly understood. Most existing studies rely on static indicators and lack continuous environmental records, limiting the detection of nonlinear transitions and threshold effects. By integrating records of combustion-derived pollutants (polycyclic aromatic hydrocarbons, spheroidal carbonaceous particles, and soot with its fossil fraction) collected from a 121-year sediment core in Sihailongwan Maar Lake with historical socioeconomic datasets, this study constructs the coupling index based on the rate of change to characterize the temporal evolution of atmospheric-socioeconomic linkages, and quantifies the relative contributions of key driving factors to historical pollution trends using Logarithmic Mean Divisia Index decomposition. Our results reveal a transition towards weak decoupling in the early 21st century, with an Environmental Kuznets Curve turning point for combustion-derived pollution emerging at a per capita GDP of approximately 11,500-13,320 Yuan (in constant 2015 prices). Decomposition analysis shows that from 1900 to 2021, economic out increased air pollution levels by a factor of 245 and population growth by a factor of 30, whereas controls in energy intensity and emission intensity reduced them by factors of 131 and 117, respectively. This work underscores the potential of geological archives to trace human-environment coevolution, offering insights for addressing sustainability dilemmas in industrial regions.

Against China's backdrop of substantial on-road vehicle emission reductions, nonroad sources-particularly agricultural machinery (AM)-have become significant contributors to elemental carbon (EC). The impact of rapidly updated fuels and emission standards on AM's particle size-resolved EC and health effects remains unclear. This study measured EC size distributions from five AM units, further evaluating fuel types (petrodiesel B0 vs biodiesel B5/B20) and emission standards (Stage II vs Stage III) on emission characteristics and size distributions. The results show that (1) AM's mean EC emission factor (EF) was 367.3 +/- 476.5 mg/kg-exceeding typical on-road mobile sources-with char-EC and soot-EC comprising 7.3% and 92.7% of EFEC respectively. (2) Fuel type and emission standards exerted significant influence on EC emissions, particularly within the ultrafine particle fraction. Newer standards increased ultrafine EC emissions by 3.6-fold and using B20 elevated total EC by 24.3% versus using B0. (3) By incorporating deposition and clearance efficiency across different particle sizes, modeled respiratory deposition of EC yielded 237.9 mg/kg (children) and 163.9 mg/kg (adults). The pulmonary region constituted the primary deposition target site, then head airways, with the tracheobronchial receiving the least. This work provides essential data for evaluating AM emissions under new frameworks.

The term ‘Anthropocene’ was coined in recognition that human activities have ended the relatively stable environment of the Holocene epoch. However, its widespread adoption across the humanities, arts and sciences has led to diverse and sometimes incompatible definitions. In this Perspective, we argue for a stabilized definition of the Anthropocene epoch to help address contemporary environmental challenges, and explore various applications of the Anthropocene across disciplines. The Anthropocene epoch, with a proposed start point in 1952, underscores that human-driven global-scale environmental disruption differs from earlier human impacts of the Holocene, which did not cause such profound destabilization. This clear distinction enables quantitative and qualitative comparisons between the Holocene and Anthropocene epochs, as already utilized, for instance, within the planetary boundaries framework. As the Anthropocene Earth system transformation is systemic, political responses also need be systemic, rather than ad hoc. A unified Anthropocene epoch would help facilitate systematic, actionable climate and environmental policies. By contrast, alternative, extended interpretations of the Anthropocene are used to reflect accumulated human environmental impacts over many millennia. These broader interpretations portray the totality of anthropogenic change but obscure the quantitatively established departure from Holocene conditions. Applying a consistent Anthropocene epoch definition will improve its utility to science, scholarship and policy. The Anthropocene is a term applied across geological, environmental and social sciences, and the humanities and arts. This Perspective explores various applications of the term and discusses how a consistent definition could support transdisciplinary efforts to address modern environmental challenges.

Abstract. Urban areas account for the majority of global CO2 emissions, yet direct observational evidence of emission reductions under climate mitigation policies remains limited. Here we combine eddy covariance measurements with tree-ring radiocarbon (14C) to quantify changes in urban CO2 emissions and attribute their sources in two megacities, Beijing and Xi’an, from 2020 to 2024. We find that all urban sites remained net carbon sources but exhibited consistent interannual declines in CO2 fluxes, with the strongest reductions during heating season and traffic peak hours. Compared to 2021, the CO2 fluxes in Beijing and Xi’an in 2024 reduced by 21.6% (1.1 kg C m⁻2 yr⁻1) and 41.2% (0.7 kg C m⁻2 yr⁻1), respectively. Independent constraints from tree-ring 14C reveal a concurrent decrease in fossil fuel-derived CO2 (CO2ff), demonstrating that the observed emission reductions are primarily driven by declining fossil fuel combustion. Analysis of energy consumption data indicates that these reductions are associated with substitution of coal and petroleum with electricity and natural gas, as well as rapid adoption of new energy vehicles. Our results provide direct observational evidence that urban carbon emissions can decline under climate mitigation policies and highlight the central role of energy system transformation in achieving sustained emission reductions.

The Geological Time Scale provides a global framework for correlating major Earth system changes over geological history. The Anthropocene term is widely used to describe transformative human impacts on the environment but lacks a formal Geological Time Scale definition, and hence is applied and interpreted inconsistently. In this Perspective, we summarize multi-proxy evidence from 12 globally distributed stratigraphic records to show that mid-twentieth century Earth system changes are abrupt, globally synchronous, and stratigraphically distinct, providing a basis for precisely defining the Anthropocene as a series and epoch. Accelerated fossil fuel combustion, industrial pollution and biosphere transformation have caused extensive climate, environmental and ecosystem disruptions that are recorded in stratigraphic successions. Atmospheric carbon dioxide and methane concentrations at 51% and 157% above Holocene levels have driven global temperatures to 1.5 °C above pre-industrial levels, marking a substantial departure from earlier relatively stable climatic conditions. A sharp global plutonium increase in 1952, related to above-ground thermonuclear detonations, provides the most suitable primary marker for establishing the Anthropocene’s base, supported by an array of proxies, many unique to the Anthropocene. Formal recognition of the Anthropocene on the Geological Time Scale would communicate the scale and abruptness of human-driven Earth system change, distinct from the less pronounced human impacts during the Holocene. The Anthropocene is widely used without fixed definition. This Perspective argues for its base to be defined in 1952 by a sharp plutonium upturn coinciding with changes in multiple proxies, providing a globally correlatable horizon reflecting substantial human-driven Earth system disruption.

The gas-particle partitioning of carbonyl compounds through reversible and irreversible pathways constitutes a critical route for secondary organic aerosol formation. This study simultaneously observed distribution of formaldehyde (FA), acetaldehyde (AA), glyoxal (GLY), and methylglyoxal (MGLY) in both gas and particle phases, as well as concentration and stable carbon isotope (δ¹³C) of oxalic acid. The results show that in the reversible partitioning process, the carbonyl compounds during clean period are mainly partitioned into organic phase, and the salt-in effect exhibits kinetic limitations. However, they are mainly partitioned into aerosol liquid water during haze periods with lower partitioning coefficients, and there is a significant salt-in effect. The carbonyls present different irreversible partitioning pathways to contribute oxalic acid formation in haze periods. In Haze I (O3: 24 ± 11 ppb), the carbonyl compounds are mainly partitioned into aqueous phase and reacted with water to form polymers or undergoing self-polymerization. The large multifunctional compounds decomposed to yield oxalic acid, leading to progressive enrichment of δ¹³C. In Haze II (O3: 41 ± 13 ppb), the elevated atmospheric oxidation capacity promoted aqueous-phase oxidation of the carbonyls to generate intermediate products and ultimately forming oxalic acid. Under these conditions, oxalic acid-C exhibited a depleted δ¹³C signal.

The gas-particle partitioning of carbonyl compounds through reversible and irreversible pathways constitutes a critical route for secondary organic aerosol formation. This study simultaneously observed distribution of formaldehyde (FA), acetaldehyde (AA), glyoxal (GLY), and methylglyoxal (MGLY) in both gas and particle phases, as well as concentration and stable carbon isotope (δ¹³C) of oxalic acid. The results show that in the reversible partitioning process, the carbonyl compounds during clean period are mainly partitioned into organic phase, and the salt-in effect exhibits kinetic limitations. However, they are mainly partitioned into aerosol liquid water during haze periods with lower partitioning coefficients, and there is a significant salt-in effect. The carbonyls present different irreversible partitioning pathways to contribute oxalic acid formation in haze periods. In Haze I (O3: 24 ± 11 ppb), the carbonyl compounds are mainly partitioned into aqueous phase and reacted with water to form polymers or undergoing self-polymerization. The large multifunctional compounds decomposed to yield oxalic acid, leading to progressive enrichment of δ¹ ³C. In Haze II (O3: 41 ± 13 ppb), the elevated atmospheric oxidation capacity promoted aqueous-phase oxidation of the carbonyls to generate intermediate products and ultimately forming oxalic acid. Under these conditions, oxalic acid-C exhibited a depleted δ¹ ³C signal.

Elemental carbon (EC), predominantly produced by solid fuel combustion, significantly influences both climate and public health. However, the physicochemical properties of EC-containing particles immediately after emission remain inadequately understood. This study investigates the chemical composition, size distribution, and mixing state of EC-containing particles from five solid fuels: wheat, corn, rice straw, bituminous coal, and anthracite. Using a single-particle aerosol mass spectrometer (SPAMS), we identified seven distinct EC-containing particle types. Our results show that biomass burning primarily produces EC-containing particles obviously coated with organic carbon (EC-OC) and organic nitrogen (EC-CN), with sizes concentrated between 0.4 and 1.0 μm. In contrast, bituminous coal emissions are dominated by sodium-rich EC-containing particles (EC-Na), while anthracite combustion predominantly produces particles coated with sulfate or nitrate (EC-NS). Bituminous coal particles are generally smaller ( < 0.4 μm), likely due to higher volatile content and rapid pyrolysis. The mixing states of EC-containing particles varied markedly. Sulfate (97HSO4−) was strongly associated with EC-OC and EC-Na particles, resulting in a highly mixing state. Levoglucosan (59C2H3O2−) showed distinct patterns between biomass and coal emissions. These findings provide critical insights into the physicochemical properties of freshly emitted EC-containing aerosols, offering valuable references for atmospheric particle analysis and emission characterization.

Timeframe is a critical factor in understanding the impact of climate change on the evolution of microbial community structure and ecological memory. Here, we demonstrate how bacterial functions have left lasting imprints through their inherent gene-regulatory network traits under alternating wet and dry climatic conditions over loess-paleosol geological time scales. In the drier loess soil, Gammaproteobacteria possess symbiotic nitrogen-fixing genes that promote microbial structural and functional succession over the ten-thousand-year scale and support a nitrogen fixation-comammox-nitrate reduction cycle and nitrogen memory, according to analysis of samples in Luochuan, China. The unique and extreme conditions of the paleoclimate environment can be reflected in the microbial community composition. Nitrogen deficiency in drier loess soil has facilitated shifts in bacterial phyla community composition, driving the evolutionary functional pathways and strong legacy effects. Our findings highlighting the crucial role of specific traits of Gammaproteobacteria as driving forces for stabilizing microbial systems in arid soils. In the drier loess soil, Gammaproteobacteria possess symbiotic nitrogen-fixing genes that promote microbial structural and functional succession over the ten-thousand-year scale and support a nitrogen fixation-comammox-nitrate reduction cycle, according to analysis of samples in Luochuan, China.