This study focuses on the phenological changes of Stipa krylovii steppe in Inner Mongolia and their responses to the maximum and the minimum air temperature, based on MODIS NDVI data and corresponding ground-based phenological observations from 2000 to 2024. The HANTS method was employed to reconstruct NDVI time series, and the start of season (SOS) and the end of season (EOS) were obtained using a dynamic threshold method. The results showed that: (1) the thresholds of 50% for SOS and 65% for EOS resulted in the lowest extraction errors, with RMSE values of 8d and 11d, respectively; (2) from 2000to 2024, the SOS advanced at a rate of 0.32d/10a, while the EOS was delayed at a rate of 0.12d/10a, indicating a prolonged growing season; (3) the EOS was more sensitive to air temperature than the SOS, the daytime mean maximum temperature had a significantly stronger advancing effect on EOS than the nighttime mean minimum temperature. This study determined the remote sensing-based optimal thresholds of Stipa krylovii steppe phenology, revealed the effect of air temperature on phenological change, and provided a scientific basis for steppe management under climate change.

Based on the the ecological footprint model, this paper analyze the characteristics of natural capital utilization and comprehensive ecological security situation in CPUA from 2010 to 2021. The weighted Voronoi diagram was used for ecological security zoning, and partial least squares regression was employed to identify the main driving factors. The results revealed that: (1) the per capita ecological footprint (ef) of CPUA increased by 11.27%, while the per capita ecological carrying capacity (ec) remained relatively stable. The per capita ecological footprint size (EF_size) ranged from 0.289~0.300hm²/cap, whereas the ecological footprint depth (EF_depth) ranged between 2.595~2.928 and maintain an upward trend. (2) The ecological pressure index, ecological coordination index, stock-flow usage ratio, and ecological footprint diversity index demonstrated a gradual decline in ecological security situation. The improvement of ecological utilization efficiency contained the trend of ecological deterioration effectively. The comprehensive ecological security index was generally in a "medium insecurity" state. (3) Based on the weighted Voronoi diagram, the CPUA was divided into central core development zone, western transformation development zone, northern optimization development zone, eastern protection development zone, and southern green development zone. (4) The proportion of primary industry output value and the total energy consumption were important positive driving factors in most regions, while the influence of other factors on ecological security varied significantly in different regions.

An investigation was conducted to examine the influence of runoff input on the water quality of stratified reservoirs and to identify optimal artificial control strategies for positioning the intrusive layer, so as to enable the withdrawal of high-quality water. High-frequency and comprehensive in-situ monitoring of water quality indicators for spring snowmelt and summer storm runoff was conducted at Lijiahe reservoir (LJHR) in the northern foothills of the Qinling Mountains, to analyze the pollution characteristics, intrusive layer, and reservoir water quality response mechanisms. The results indicated that ① nitrogen/phosphorus (N/P) concentrations in runoff were significantly higher than those in baseflow, with snowmelt runoff was dominated by dissolved nutrients, while storm runoff contained dissolved N but particulate P. Moreover, N/P concentrations in storm runoff were significantly greater than those in snowmelt, which was attributed to differences in discharge. ② The effects of suspended solid (SS < kg/m³) on water density was neglected in the three runoffs events, and three different intrusive layers can be formed based on the differences between the runoff water temperature and the surface and bottom water temperatures of the reservoir. The water temperature of snowmelt runoff was typically higher than that of the reservoir bottom layer, leading to the development of overflows. Additionally, the abundance of available nutrients and the stable water environment during the early stages of reservoir stratification promoted rapid algal growth in the surface layer, which could easily induce algal blooms. ③ Prior to storm runoff inflow, the Water-lifting aerators system (WLAs) was used to regulate the intrusive layer of runoff seepage by modifying the vertical thermal structure of the reservoir. During the July torrential rain event, intermittent operation of the WLA resulted in higher water temperatures in the storm runoff [(18.46 ± 0.76)℃] compared to the bottom layer (16.67℃), leading to the formation of an interflow (837.9~815.6m). In September, continuous operation of the WLA raised the bottom water temperature to 19℃ before the storm inflow, which was higher than that of the incoming runoff [(12.35±0.59)℃], thereby inducing an underflow (800~828.2m). ④ Nutrient concentrations were significantly elevated in the intrusive layer, the formation of underflow induced by WLA placed the intrusive layer below the intake elevation (832m), effectively mitigating the impact of high-pollution-load runoff on water supply quality. Additionally, the compression of the intrusive layer reduces its thickness, thereby shortening the duration of its effects on water quality. This study provides a practical engineering reference for ensuring the safety of reservoir water supply. It is recommended activating the WLA at the early stages of reservoir stratification to inhibit algal blooms caused by snowmelt runoff and to increase the reservoir bottom water temperature above that of the runoff, thereby inducing the formation of underflow from runoff to achieve "high-quality mid-level water intake" during the storge period while ensuring "turbidity reduction and water clarity" during peak floods events.

This study focused on the coal-grain overlapping areas of the Huaihe River Basin, analyzing 31 water samples through integrated EEMs-PARAFAC and FT-ICR MS techniques to unravel DOM molecular signatures and transformation pathways under intense anthropogenic disturbances. Key findings include: (1) PARAFAC identified three fluorescent components (C1: UV humic-like; C2: terrestrial humic acid; C3: tryptophan-like), where intensity distribution (C1 > C3 > C2) and spectral indices (FI=(1.77 ± 0.12); HIX = (0.73 ± 0.07)) revealed dual DOM origins from terrestrial inputs (agricultural tributaries) and microbial degradation (urbanized mainstream), highlighting their synergistic interactions. (2) FT-ICR MS unveiled a distinct "upstream agriculture-downstream industry" spatial gradient: CHO and CHON molecules dominated agricultural headwaters, while CHOS compounds increased downstream, governed by PAHs oxidative ring-opening and thioether-to-sulfonic-group conversion. (3) DOM in coal-grain overlapping areas exhibited "sulfur/nitrogen-enriched, multi-source coupling" characteristics. Elevated CHON proportions (33%~37%) in tributaries correlated with fertilizer-derived deamination processes, whereas downstream photochemical-metal co-catalysis (Fe²⁺/H₂O₂) triggered radical cleavage of "coal-sulfur" pollutants, generating highly aromatic, low-oxidation-state stable products. These findings elucidate the dual natural-anthropogenic regulatory mechanisms of DOM, providing molecular-level insights for organic pollutant source tracing and non-point source management in the basin.

By constructing a SWAT model, this study simulated the variations in runoff and nitrogen/phosphorus load fluxes at control sections of the Yanjin River Basin in 2023, analyzed the spatiotemporal characteristics of point and non-point source load emissions, and evaluated the applicability of the SWAT model in the karst region of southwestern China. The results show that: during the validation period, the SWAT model achieved R² values of 0.77, 0.82, and 0.84 for runoff, TN, and TP simulations, respectively, with Nash-Sutcliffe efficiency coefficients of 0.77, 0.67, and 0.78, indicating good applicability in typical karst areas. The main emission zones for total nitrogen (TN) were distributed in the central and southwestern parts of the basin, while total phosphorus (TP) emissions were concentrated in the eastern-central and southwestern regions, reflecting spatial differences in land use and industrial activities. Agricultural non-point sources and urban non-point sources were the dominant contributors to TN and TP losses, accounting for 52% and 31.4% of the total losses, respectively. TN and TP emissions during the flood season reached 2.2 and 3 times those of the non-flood season, with significant correlations between nitrogen/phosphorus loss and rainfall intensity. TP loss was more susceptible to heavy rainfall events.

Taking Miluo City as an example, this study constructed a health evaluation system that includes four major landscape functions, and quantitatively analyzed the spatial and temporal characteristics of landscape function health in Miluo City during 2000~2020. In addition, by integrating spatio-temporal trend analysis, spatial heterogeneity assessment, and driver identification methods, the direction of landscape function evolution, distribution characteristics, and the driving factors behind them are further examined. Finally, this study analyzed the spatial and temporal evolution of the "three living spaces" in Miluo City using the SOM clustering algorithm. It was found that the overall landscape functional health of Miluo City showed a small decline from 2000 to 2020, from 0.182 in 2000 to 0.179 in 2020, and the spatial distribution showed that the areas with higher landscape functional health indices were mostly located in the southern and northeastern woodlands. In contrast, areas with rapid urban expansion have relatively poor landscape functional health. The analysis results show that the dominant factor in landscape functional health has gradually shifted from climatic conditions to human activities, with the contribution of human activities increasing from 18.3% in 2000 to 14.8% in 2020. From this trend, it can be seen that the functional health of Miluo City's landscape is more sensitive to changes in human activities in the context of accelerated global urbanization. In view of the distribution characteristics of the "three life spaces" and their changing rules in Miluo City, specific zoning control recommendations are proposed, including measures to strengthen the management of the ecological red line, adjust the mode of urban expansion, and promote the integration of agriculture and ecology.

The physicochemical properties and environmental risks of microplastics-natural organic matter (MPs-NOM) composite pollutants, which are formed by the interaction between MPs and NOM, are complex and variable. Considerable research has been conducted on the hazards of MPs and NOM, as well as strategies for their removal. However, most studies have focused on the trends of the two components in isolation, neglecting the contribution of interfacial interactions and synergistic hazards, which may lead to an underestimation of their environmental risks. Therefore, this review systematically describes the research progress on MPs-NOM composite pollutants in water, focusing on the interactions, environmental hazards, and efficient removal methods. Furthermore, future research directions are proposed from the perspectives of mechanism revelation, risk assessment, and technological innovation. The mechanisms underlying the formation, fate, and removal of MPs-NOM pollutants throughout the entire process should be strengthened to provide a scientific basis for upgrading water treatment technologies aimed at addressing new pollutants.

Layered double hydroxide modified basalt fiber (ZnFe-LDHs-BF) was applied to a constructed wetland system with vertical flow to investigate its performance and mechanisms in enhancing the treatment of antibiotic wastewater. The study involved altering initial concentrations, temperature, and pH to examine the impact on tetracycline adsorption by the modified basalt fiber. Additionally, metagenomic sequencing was used to assess the influence of the modified basalt fiber matrix on microbial communities. The study found that when the initial tetracycline concentration was 100mg/L and temperature was 25℃, after 24-hour reaction, ZnFe-LDHs-BF would have a maximum adsorption capacity of 9.19mg/g for tetracycline, over two times higher than that of traditional matrices. After incorporating ZnFe-LDHs-BF to the reactors, the average removal rates of tetracycline and erythromycin were 83.18% and 79.88%, respectively. They were 2~3 times higher than those observed in reactors with traditional gravel or unmodified basalt fiber, demonstrating enhanced purification capabilities for COD, NH₄⁺-N, and TP. Metagenomic analysis revealed that ZnFe-LDHs-BF enriched the microbial community, particularly Candidatus Promineifilum and Anaerolinea functional bacteria. Additionally, the abundance of tetracycline resistance genes (e.g., tetC, tetG) and erythromycin resistance genes (e.g., ermF, ermB) increased by 1~2 times, thereby enhancing the microbial degradation rate of antibiotics by 2~3 times.

The study was initiated with the Reynolds number (Re), and three types of microplastics—polyethylene (PE), polypropylene (PP), and polystyrene (PS)—were focused on. By employing the Lagrangian method, the longitudinal instantaneous velocity and motion trajectories of microplastics in water were investigated using high-speed camera tracking and Tracker physics software, with Reynolds numbers ranging from 300 to 580 and 580 to 3500, respectively. It was observed that at very low Reynolds numbers, the motion trajectory of microplastics was approximated by a straight horizontal line, with small absolute error and standard deviation. Reynolds number reached or exceeded the critical value (575~580), transition and turbulence caused a significant increase in longitudinal instantaneous velocity. As a result, the original linear paths were deviated from by the microplastics. Overall, a normal distribution was followed by the longitudinal velocity of microplastics in water. Greater deviation from the standard normal distribution was exhibited by PS, along with more uneven instantaneous velocity fluctuations, and its travel distance in the flow direction was found to be harder to predict. In addition, the total travel distance of microplastics was increased by 0.4‰~6‰compared to straight-line motion, due to flow transition and turbulence.

To evaluate the greenhouse gas (GHG) emissions and mitigation potential in the transportation sector of Henan Province, localized vehicle emission factors were calculated based on the COPERT model. A 3km × 3km gridded emission inventory was established using ArcGIS, and the spatiotemporal dynamics of vehicle-related GHG emissions were systematically analyzed. Vehicle ownership in Henan Province from 2025 to 2035 was forecast by combining the Gompertz function with the elasticity coefficient method, and emission trends under multiple policy scenarios were examined. The results showed that total vehicle GHG emissions increased from 140 million tonnes to 160 million tonnes during 2019 to 2023, with an average annual growth rate of 2.9%. Carbon dioxide (CO₂) accounted for more than 98% of total emissions, while light-duty passenger cars and heavy-duty trucks were identified as the primary contributors. Urban road traffic was responsible for 78.8% of total emissions, and high-emission areas were concentrated in core cities such as Zhengzhou and Luoyang, presenting a spatial pattern of central clustering and peripheral diffusion. Under the baseline scenario, total GHG emissions were projected to reach 170 million tonnes by 2035. In contrast, when new energy vehicle promotion, green commuting, and accelerated retirement of aging vehicles were jointly implemented, total emissions were reduced to 70 million tonnes, representing a 58.1% decrease compared with the baseline. These findings provided quantitative evidence to support carbon management and the optimization of mitigation pathways in the transportation sector of Henan Province.