Lake sediments are valuable archives for reconstructing regional histories of trace metal contamination and evaluating the environmental impacts of human activities. Although studies on lacustrine sediments in southwestern China have improved our understanding of modern contamination trends, trace metal accumulation and its environmental effects during historical periods-particularly the Ming and Qing dynasties-remain poorly constrained. This limitation may lead to underestimation of anthropogenic inputs when pre-industrial background values are used as the baseline and may obscure the long-term environmental legacy of early mining and smelting activities. Here, we used a well-dated sediment core from Dalongtan Crater Lake to reconstruct high-resolution records of Pb, Sn, Sb, Bi, Cu, and Ag over the past millennium to apportion natural and anthropogenic sources. The results indicate that 1250-1640 CE corresponds to relatively low enrichment levels, suggesting limited anthropogenic influence. From 1640 to 1950 CE, a pronounced mining-smelting contamination signature emerged, marked by synchronous enrichment of Pb, Sn, Sb, and Bi that closely aligned with historically intensified regional metallurgical activity. Since 1950 CE, Pb and Sn have declined, whereas Sb has increased exponentially, consistent with a transition from metallurgy-dominated inputs to combustion-related atmospheric emissions. These findings demonstrate that using pre-industrial background values as the sole baseline can substantially underestimate the extent of modern contamination and mask the long-term legacy of historical metallurgical activity. Our results provide a basis for more accurate assessments of human-environment interactions and inform evidence-based contamination mitigation strategies in southwestern China.

Since the Industrial Revolution, human activities have significantly increased atmospheric black carbon (BC) aerosols, harming air quality, human health, and regional climate. Although the research on the characteristics and sources of atmospheric BC has expanded, understanding of its cross-sea transport remain limited. Zhanjiang city, located on the coast of the northern South China Sea, experiences pronounced monsoon influences and has heavy industries. However, this region maintains good air quality. We hypothesize that monsoon circulation may significantly influence BC pollution. To verify this hypothesis, aerosol samples were continuously collected in Zhanjiang from 2018 to 2019. Results showed clearly seasonal variations in BC concentration and its carbon isotopic values, indicating they are not primarily influenced by local emission sources, as local emissions remain relatively constant. Instead, lower values in summer and higher values in other seasons align closely with monsoon transitions, suggesting that a significant role of monsoon circulation in driving these variations. Backward trajectory model (HYSPLIT) and the potential source contribution factor analysis model (PSCF) further revealed distinctly different air mass pathways between summer (ocean air masses) and other seasons (terrestrial air masses). A Bayesian mixing model indicated that the combustion of fossil fuels (58 %, including 30 % of liquid fuel and 28 % of coal) is the predominant source of BC entering Zhanjiang with air masses. Correlation analyses with water-soluble inorganic ions revealed that BC exhibited significantly weaker associations with terrestrial pollution compared to TC, due to substantial contributions from secondary aerosols to TC during longrange transport. This study suggested that monsoon-driven circulation plays a critical role in aerosol transport and composition in the coastal region, providing new insights into atmosphere-ocean carbon exchange.

Heavy metals have accumulated continuously during industrialization and agricultural expansion, posing serious threats to ecosystems and human health. Accurately identifying natural baselines and quantifying anthropogenic forcing are essential for effective pollution control. However, most previous studies relied on static baselines, lacked quantitative characterization of threshold exceedance, and were limited in temporal scope. This study focuses on Sihailongwan Maar Lake (SHML) in northeastern China, reconstructing a 1,600-year high-resolution history of heavy metal accumulation. Results show a critical shift around 1930 CE from natural to anthropogenic control. Before 1930 CE, concentrations remained at natural levels; afterward, rapid industrialization and agricultural expansion became the dominant drivers, sharply increasing pollution. Using a Dynamic Natural Baseline (DNB) and Baseline Deviation Multiple (BDM), Cd and Pb exhibited the strongest anthropogenic deviations, while Zn, As, Hg, Sb, and Cr showed moderate levels. A Threshold Exceedance Index (TEI) further distinguished disturbance types: Cd, Pb, Sb, and Zn displayed sustained forcing, remaining at high levels, whereas As, Hg, and Cr showed transient forcing with reversible, stage-dependent exceedance. By integrating DNB, BDM, and TEI, this study proposes an analytical approach to quantitatively identify threshold-exceedance processes, providing a robust scientific basis for understanding the evolution of heavy metal pollution under anthropogenic forcing and for developing targeted pollution control strategies.

Paleofire studies have provided critical long-term data on past fire dynamics. However, previous research has predominantly focused on the influence of climatic factors on paleofires, paying little attention to the role of climatic stability. Here, we use a precisely established varve chronology to reconstruct a similar to 1400-year high-resolution fire history from charcoal and soot records in the sediments of Sihailongwan Maar Lake, a representative forested region of northeastern China. We further investigate the role of climatic stability in controlling fire frequency and size. We show that during periods of climatic instability (ca. 900-1100 CE, ca. 1250-1500 CE, ca. 1600-1800 CE), fire frequency markedly increased, while the individual fires were generally small. In contrast, during periods of climatic stability (ca.710-900 CE, ca. 1100-1250 CE, ca. 1500-1600 CE), fires occurred less frequently but were larger in size. Climatic stability regulated fire dynamics by affecting fuel accumulation and moisture content through climatic whiplash (extreme wet-dry oscillations). Against the recent backdrop of rapid global warming and regional anthropogenic fire suppression, the potential risk of fires may increase dramatically. Our result supports a policy of shifting fire suppression policies toward an "healthy forest" management to balance ecological conservation and fire management needs.

Mesoscale eddies are active physical features of the ocean that exert a strong influence on the biogeochemical cycling of organic matter. However, their integrated roles in structuring coupled particulate and dissolved organic matter (POM and DOM) dynamics remain poorly understood, limiting the mechanistic understanding of their net effect on carbon export and sequestration. To address this knowledge gap, we conducted a multi-parameter investigation across a cold-warm pair of mesoscale eddies in the northwestern Pacific Ocean, combining hydrographic observations with stable isotope analyses of POM (delta 13C-POC and delta 15N-PN) and optical characterization of chromophoric and fluorescent dissolved organic matter (CDOM and FDOM). Our results show that the cold and warm eddies represent two contrasting regimes of organic matter production and transformation. The cold eddy, despite enhanced nutrient supply through upwelling that stimulated the production of fresh phytoplankton-derived POM, exhibited relatively low inventories due to rapid biological degradation, indicative of a high-turnover process. In contrast, the warm eddy functioned as a degradation reactor, where downwelling and subduction of surface organic matter and rich-oxygen water fueled elevated microbial reprocessing, as evidenced by 13C-enriched particulate organic carbon and enhanced production of recalcitrant humic-like DOM. These findings indicate that in the specific pair of eddies investigated, cold and warm eddies can support complementary carbon pathways, with cold eddies promoting a rapid biological pump and warm eddies fostering microbial reprocessing that shifts organic matter toward the dissolved pool. The relative importance of these pathways is therefore likely to influence the carbon sequestration potential of eddy-rich regions in the open ocean.

Understanding long-term phosphorus (P) fraction dynamics in lake sediments and their responses to changes in soil erosion are critical for aquatic environmental management. However, the interactions between climate, vegetation, and soil erosion in regulating lacustrine P fractions and primary productivity remain poorly constrained. Here, we provide a comprehensive analysis of P fractions in Huguangyan Maar Lake (HML) sediments, integrated with soil erosion records, pollen assemblages, paleoclimate data, and productivity proxies derived from previous HML studies. Our results reveal the following order of P fraction abundance in HML sediments: aluminum-bound P (NaOH-P-i) > residual P (Res.-P) > iron and manganese (hydroxide)-bound P (NaBD-P-i) > calcium-bound P (HCl-P-i). According to variations of the different P fractions over the past 1400 years, four main stages were divided. During periods with weak soil erosion (before similar to 830 CE and since 1880 CE), high tree cover increased total organic P (TPo), NaOH-P-i and Res.-P in the weathering products of surrounding rocks, resulting in an increase of these P fractions in the sediments. Lower contents of TPo, NaOH-P-i, and Res.-P were observed for the periods 830-1390 CE (the Medieval Climate Anomaly and its transition to the Little Ice Age) and 1390-1880 CE (the Little Ice Age, high-erosion intervals), which could be attributed to less trees with dominance of herbs and shrubs. Regional precipitation changes may indirectly affect NaBD-P-i and HCl-P-i by influencing duration and degree of lake water stratification and the carbonate ion levels in the water body, respectively. The synergistic effects of erosion, vegetation, and climate ultimately controlled the primary productivity of HML. These findings enhance our understanding of how environmental factors affect lake sediment P fractions and lacustrine productivity, offering insights for long-term lake conservation strategies.

Abstract The viscosity of Earth’s asthenosphere regulates plate motion and surface deformation. Assessing asthenosphere rheology in subduction-zone backarcs is as crucial as in forearc and arc regions for understanding subduction dynamics. High heat flow and low seismic velocities in backarcs suggest a low viscosity, yet its geodetic evidence remains elusive. Here, we leverage 12–20 years of geodetic observations from Thailand, Malaysia, and Singapore to provide the evidence. We observe sustained far-field postseismic motion following great earthquakes in the Sumatran subduction zone and Wharton Basin extending over 600 km from the ruptures. Using layered spherical Earth models, we demonstrate this deformation requires a weak asthenosphere with viscosity on the order of ~1018 Pa s, with or without an even weaker lithosphere-asthenosphere boundary. These findings lend support to the conceptual model of buoyancy-driven small-scale thermal convection in subduction-zone backarcs. The extensive postseismic deformation due to the weak asthenosphere also affects sea-level projections.

Understanding the responses of wildfires to long-term climate variability is critical for improving fire management strategies and maintaining ecological stability. However, the spatial heterogeneity and drivers of wildfires in the East Asian monsoon (EAM) region on orbital timescales remain poorly constrained. In this study, wildfire dynamics across the last five glacial-interglacial cycles were determined based on a similar to 480 kyr wildfire history reconstructed from black carbon (BC) records in the Huangshan loess-paleosol sequence in northeastern China. The results revealed substantial glacial-interglacial cycles in northeastern China, with more intense fires during interglacials than glacials. Comparative analysis with other wildfire records revealed notable spatial heterogeneity of wildfires across the EAM region on the glacial-interglacial timescale. Wildfires in the eastern East Asian monsoon (EEAM) region were more active during interglacials, likely due to higher temperatures and greater biomass availability. Conversely, those in the western East Asian monsoon (WEAM) region were more frequent during glacials because of fuel desiccation caused by reduced precipitation. Overall, the large-scale spatial precipitation pattern, which gradually decreased from southeast to northwest in the EAM region, may serve as the core driver of wildfire spatial heterogeneity. Under future global warming, the EEAM region will likely face elevated wildfire risks and should be prioritized for fire prevention.

Elevation-dependent warming has been documented across major mountain ranges worldwide. Vegetation phenology serves as a sensitive indicator of ecosystem responses to climate change, and related metrics can reveal changes in vegetation productivity and in the global carbon budget. However, existing studies have mostly focused on the elevation dependence of climate change, whereas the characteristics and mechanisms of elevation-dependent changes in vegetation phenology remain poorly understood. The Tibetan Plateau, the worlds’ highest plateau, is an ideal region for investigating the relationship between phenological changes and elevation. This study selected Gaoligong Mountain on the southeastern margin of the Tibetan Plateau as the study area and used high spatiotemporal resolution remote sensing data to examine the elevation dependence of vegetation phenology and its response to climate change. The results indicated a significant “Z”-shaped nonlinear relationship between vegetation phenology and elevation, with critical thresholds at 2600 and 3600 m. Temperature had the largest effect on phenology below 2600 m, temperature and water availability were dominant factors at 2600–3600 m, and minimum temperature was dominant above 3600 m. These findings indicate that temperature was the primary factor affecting the elevation dependence of phenology, whereas precipitation and solar radiation had modulating effects that varied across elevation belts. The coupled relationships among topography, climate, and vegetation on the southeastern margin of the Tibetan Plateau improve understanding of phenological responses in complex mountain ecosystems.

Since the pre-industrial era, human activities have drastically increased reactive nitrogen (Nr) deposition in lakes, altering nitrogen (N) cycles. To trace its continental-scale footprints, we synthesized dated sediment δ15N records from 51 remote lakes across North America, Europe, and East Asia. Results reveal that the accelerated declines in δ15N (indicating increased Nr deposition) occurred earlier in North American and European lakes (~1950 CE), coinciding with the Great Acceleration, while similar changes in East Asian lakes appeared around 1985 CE, paralleling China’s rapid socioeconomic development. δ15N in North American lakes reversed around 2005 CE (~10%), and earlier in European lakes (~1995 CE) with more pronounced (~40%) increases. Meanwhile, East Asian lakes showed no reversal (only a slowdown in the δ15N decline). These regional differences match the timing and implementation of N emission policies, underscoring the need for region-specific and multi-N species (e.g., NHx and NOy) mitigation strategies to protect lake ecosystems. Enhanced deposition of anthropogenic nitrogen in North American and European lakes emerged during the Great Acceleration (post-1950), while shifts in East Asian lakes appeared after the 1980s, based on isotopic analysis of sediment cores from 51 lakes across East Asia, North America, and Europe.

Coastal mangrove restoration often fails when seedlings are planted outside their suitable elevation range. Although controlled experiments have improved our understanding of mangrove responses to flooding, many previous studies imposed static flooding regimes with fixed durations, failing to capture the dynamic hydroperiod (i.e., timing, frequency, and duration of inundation) characteristic of natural tides. To provide more realistic experimental conditions, we developed a dynamic tidal inundation simulation system based on the semidiurnal tidal pattern of Zhanjiang Bay, China, and exposed one-year-old seedlings of five mangrove species (Avicennia marina, Kandelia obovata, Rhizophora stylosa, Aegiceras corniculatum and Bruguiera gymnorhiza) to five elevation levels (190–310 cm), corresponding to 14.4 to 4.0 h per day of inundation, for 120 days. We quantified seedling growth, biomass allocation, root traits, foliar chlorophyll content and stress-related physiological indicators; and then evaluated the overall performance using principal component analysis. Across the five species, responses followed a promotion-inhibition pattern along the inundation gradient; moderate flooding enhanced soluble protein content and photosynthetic performance, whereas excessive flooding reduced leaf number and chlorophyll content and increased lipid peroxidation. Seedling performance remained relatively stable at elevations ≥250 cm, while marked growth limitation occurred below 220 cm. The species-specific optimal elevations were identified to be at +90 cm above mean sea level (MSL) for A. marina and K. obovata, and at +60 cm above MSL for A. corniculatum and B. gymnorhiza, while R. stylosa tolerated elevations down to MSL (0 cm). These elevation thresholds, which correspond to distinct hydroperiod ranges, provided practical guidance for species selection, elevation zoning and planting configuration in mangrove afforestation and climate-adaptive coastal ecological restoration. Their application may help reduce seedling mortality and enhance the cost-effectiveness of large-scale restoration planning, while supporting more adaptive and resilient coastal ecosystem management.

Coastal nitrogen (N) cycling is vulnerable to typhoon disturbances, yet the pathway-specific mechanisms, particularly how typhoon tracks regulate N sources and transformations, remain unclear due to methodological limitations in distinguishing biotic and abiotic processes. Here, we employed nitrate (NO3-) dual isotopes (δ15N-NO3- and δ18O-NO3-) to study the distinct N cycling pathways in Zhanjiang Bay following two typhoons with contrasting landfall tracks. The results demonstrate that the typhoon track not only determines hydrodynamic patterns but also fundamentally alters the nature of N cycling. Specifically, different landfall tracks of typhoons lead to distinct N cycling patterns. For the left-side landfall typhoon (Lionrock), onshore winds established a salinity front that intensified sediment resuspension. The isotopic evidences revealed that this physical regime triggered adsorptive NO3- loss onto suspended particles, a quantitatively important but previously overlooked abiotic NO3- removal pathway during such events. Concurrently, source apportionment indicated that this physical retention mechanism trapped > 70 % of municipal sewage-derived NO3- within the bay. In contrast, the right-side landfall typhoon (Chaba) generated offshore winds, flushing the bay with terrestrial nutrients and stimulating intense phytoplankton blooms. The isotopic evidences suggested that phytoplankton assimilation is the dominant NO3- consumption process. Therefore, the typhoon track acts as a switch that flips between two distinct N fates, including physicochemical processes (dominated by the left-side landfall typhoon) and biological process (dominated by the right-side landfall typhoon). This N-centric framework provides actionable insights for coastal management, showing that left-side typhoons may exacerbate localized eutrophication risks from point sources, while right-side typhoons drive basin-wide biological responses.

The source of atmospheric nitrous acid (HONO) has not yet been fully identified, as observed concentrations remain significantly higher than predicted levels. The hydrolysis reaction of t-ONONO2, as a feasible source of HONO, has attracted much attention in the field of atmospheric chemistry. In this study, the roles of sulfuric acid (SA), methanesulfonic acid (MSA), and methyl hydrogen sulfate (MHS) in the hydrolysis reaction of t-ONONO2 to produce HONO and HNO3 were explored by DFT and statistical dynamics methods. Thermodynamic and kinetic data indicate that SA, MHS, and MSA enhance the hydrolysis reaction of t-ONONO2 through two mechanisms: single hydrogen atom transfer (S-HAT) and double hydrogen atom transfer (DHAT). Among these, SA exhibits the strongest catalytic effect. This study will contribute to a better understanding of the mechanistic characterization of t-ONONO2 hydrolysis reactions, which is of great significance for the control of atmospheric particulate matter in polluted areas.

The study of modern pollen-vegetation relationships is fundamental for improving the reliability of palaeovegetation reconstructions. This study investigates the spatial variation of pollen assemblages, pollen depositional processes, and the spatial representation of regional vegetation in Liangzi Lake-a large shallow lake in the middle reaches of the Yangtze River. Results indicate that the surface pollen assemblages can be clearly divided into western and eastern zones with significant compositional differences. The western zone exhibits greater spatial heterogeneity and lower evenness, whereas the eastern zone shows higher consistency and diversity, positioning the latter as an ideal coring area. Different palynomorph groups respond differentially to hydrological gradients. Arboreal pollen is insensitive to water depth and distance from shore, providing a stable record of regional vegetation. In contrast, terrestrial herb pollen diversity decreases significantly with increasing water depth, reflecting the attenuation of near-shore signals in deeper waters. Algal spores are the most sensitive to hydrological variables; specifically, Coelastrum reticulatum increases significantly with water depth, while Pediastrum simplex abundance rises with distance from shore. Quantitative comparison between Regional Estimates of Vegetation Abundance from Large Sites (REVEALS) reconstructions and remote sensing vegetation data identifies an optimal vegetation representation scale of approximately 95 km, with a near-optimal interval of 85-100 km. The REVEALS model improves the consistency between reconstructions and satellite data. This study demonstrates that while surface pollen in Liangzi Lake serves as a robust indicator of regional vegetation, it is also markedly influenced by intra-lake depositional environments. For palaeoenvironmental reconstructions, it is crucial to distinguish the responses of different taxa to regional background signals from those to local hydrological processes.

The total organic carbon (TOC) content in lake sediments is an effective archive indicating past climate changes. However, the resolution of the TOC record has generally been limited by factors such as subsampling intervals, hampering further comprehension of past climate change. Recently, hyperspectral imaging technology has been increasingly employed to scan lake sediment cores, presenting new opportunities to reconstruct high-resolution sequences, but the reconstruction of long-term high-resolution TOC records using hyperspectral imaging and the climate implications have not been well studied. In this study, we scanned sedimentary cores from Wudalianchi Crater Lake in northeast China with a spatial resolution of 400 × 400 μm, utilizing visible and near-infrared (VNIR) hyperspectral imaging technology. Then, a partial least-squares regression (PLSR) model was constructed by comparing eight different preprocessing methods and optimally selecting the best spectral subset combined with a genetic algorithm (GA). Our analysis demonstrates that the PLSR model, constructed using 62 relevant bands selected by the Savitzky–Golay second derivative (D2) preprocessing method and GA, was the most reliable, with the validation set’s R-value reaching a high of 0.91 and RMSE as low as 1.18%. Notably, the spectral range of 656–669 nm showed a strong positive correlation with measured TOC, indicating its sensitivity for TOC estimation. Given this advantage, we reconstructed the TOC records of sediments from the Wudalianchi Crater Lake during the 38–13 ka BP period, which exhibited significant millennial-scale fluctuation events. These corresponded well with the millennial-scale events in pollen and TOC from Lake Sihailongwan, δ18O records of Greenland ice cores, and δ18O records from Asian stalagmites. Thus, the combination of hyperspectral imaging and the PLSR model is effective in reconstructing high-resolution TOC changes in lake sediments, which is essential for understanding climate change as well as carbon burial in lakes.

Dry-wet transitions exert critical influences on vegetation structure and function. Although centennial-scale hydroclimatic variability has been widely studied, the ecological effects of decadal-scale transitions remain underexplored. Here, we use a high-resolution precipitation index and pollen sequence spanning the last millennium from Sihailongwan Maar Lake (SHML), northeastern China, to investigate vegetation responses to decadal-scale dry-wet transitions. Dominant 10-80 year cycles were extracted using Ensemble Empirical Mode Decomposition (EEMD) and Hilbert-Huang Transform (HHT) to identify major hydroclimatic shifts. Results show that transition frequency was significantly higher during the Little Ice Age (LIA) than the Medieval Climate Anomaly (MCA), likely linked to enhanced cold vortex activity. Distinct vegetation responses were observed: wet-to-dry phases led to tree cover reduction and herbaceous expansion, marked by a decline in broadleaved trees and slight increases in coniferous trees; dry-to-wet phases showed the opposite pattern. In the mid-to-late LIA, these typical vegetation response patterns were disrupted. Lagged, inconsistent, and even reversed changes, along with asynchronous shifts among plant groups, likely resulted from a combination of high-frequency climatic fluctuations, differences in plant ecological traits, and potential sampling mismatches between parallel cores. Vegetation diversity closely tracked the dynamics of broadleaved trees, suggesting their central role in regulating diversity. Periods of diversity increase were associated with structural recovery and functional rebalancing, whereas declines indicated reduced ecosystem stability and rising vulnerability. These findings highlight the ecological significance of decadal hydroclimatic variability and underscore the need for monitoring key functional taxa and advancing multi-scale climate response frameworks to support ecosystem resilience under increasing disturbance regimes.

During the late Neolithic, the number of pottery cups unearthed in the Central Plains of China increased, yet their function remained unclear. This study investigates the functions of pottery vessels from the Shuanghuaishu site, dating to the late Yangshao to early Longshan periods (ca. 5200-4500 cal BP), using starch grain, phytolith, fungal, and organic acid analyses. The results suggest that jiandiping were not typical vessels for brewing or consuming alcohol, while the emerging pottery cups were used for drinking alcoholic beverages. Ingredients used in brewing included millets, rice, Job's tears, Triticeae, tubers, and legumes. The form and function of the cups may have been influenced by the Dawenkou Culture and introduced to support feasting and ritual activities. These findings reveal a significant phase in drinking practices in the Central Plains around 5000 BP, reflecting both intensified regional interaction and growing ritual needs of complex societies during the late Neolithic.

Ecological synchrony, the coordinated fluctuation of species or communities, is central to ecosystem stability. Yet how synchrony changes during ecological shifts remains poorly understood. This gap is particularly evident in shallow lakes, where transitions from clear, macrophyte-dominated to turbid, algae-dominated state can dramatically alter synchrony patterns, challenging ecosystem resilience. Here, we integrate century-scale multi-proxy sedimentary records (algal pigments, macrophyte macrofossils, diatom and cladoceran remains) with remote sensing data, to investigate both intra- and inter-community synchrony dynamics throughout multitrophic regime shifts in Lake Liangzi, an iconic shallow lake in eastern China floodplain. Our results reveal that the lake ecosystem experienced two distinct ecological shifts, occurring around the 1960s and 2010s. The lake was initially submerged macrophyte-dominated with low macrophyte community synchrony and limited phytoplankton abundance. Since 1960, the lake entered a gradually transitional phase due to damming and agricultural impacts, with nutrient enrichment, increased algal production, and macrophyte shifts to emergent floating groups. Correspondingly, the synchrony of algal community decreased, but macrophyte synchrony increased towards decline in community stability. Around the mid-2010s, the lake shifted to an algae-dominated regime, characterized by algal proliferation at low synchrony and sustained high synchrony within the degraded macrophyte community. Our ordination analysis identified hydrological regulation, intensified nutrient loading and rising temperatures as main drivers underlying the regime shift. The findings highlight how ecological synchrony modulates ecosystem resilience to environmental disturbances. This study underscores the importance of asynchronous responses in bolstering ecological stability and that synchrony should be recognized as a key indicator of ecological state transitions in shallow lakes.

Atmospheric phosphorus (P) deposition has a significant impact on sensitive aquatic ecosystems in remote areas. However, its effect on the P fractions of lake sediments and the development of lake ecosystems are poorly understood, especially for P-limited lakes. This study investigates this issue via analyzing trap and core sediments of Dalongwan Maar Lake (DML), a P-limited lake in Northeast China. The provenance analysis indicates that the sediments in DML are mainly derived from the aeolian input from northern China deserts, which brings P-containing particles. Then, the relationships between atmospheric P deposition and the P fractions of the DML lake sediment and its ecosystems over the past 180 years were explored. The results show that: 1) The P fractions in trap sediments exhibit significant seasonal variation, with calcium-bound P (HCl-P-i) being the predominant fractions during spring and winter, while aluminum-bound P (NaOH-P-i) and iron and manganese (hydroxide)oxy-bound P (NaBD-P-i) are more prevalent in summer and autumn. The ranking order of P fractions in the core sediments was HCl-P-i > NaOH-P-i > NaBD-P-i > Res.-P (residual P). 2) The HCl-P-i content in the sediments of DML appears to be influenced by variations in northern China dust activity, while the Fe/Al-P-i (the sum of NaOH-P-i and NaBD-P-i contents) is associated with industrial and residential emission activities. 3) A gradual increase in atmospheric P deposition activity in northern China over the past century was observed. It may hinder the development of primary productivity in DML by increasing the water hardness, which is conducive to the formation of HCl-P-i. Furthermore, deeper water depth limits nutrient recycling from the lakebed, impeding algal growth. These findings enhance our understanding of how atmospheric P deposition influences lake sediment P fractions and ecosystems and provide guidance for the long-term health of DML.