Search Results (2,727)

Microplastics (MPs), defined as plastic particles smaller than 5 mm in diameter, are an emerging class of environmental contaminants of global concern. As the “Water Tower of Asia” and a critical global ecological barrier, the environmental condition of the Qinghai–Tibet Plateau has a direct influence on the ecological security of major river systems and the well-being of populations downstream. MPs have now been detected across multiple environmental compartments on the plateau, including soils, water bodies, and glaciers. Given the fragility and ecological uniqueness of the region, systematic investigation of plastic pollution here is essential for safeguarding its ecological security. Based on current research, existing data on MP pollution across the Qinghai–Tibet Plateau are reviewed and synthesized. Evidence suggests that the abundance of MP varies significantly across different environmental media in various regions and is influenced by multiple factors. Two major potential sources are identified: local anthropogenic activities and transboundary inputs via atmospheric transport and other pathways. The unique environmental conditions of the region, such as intense ultraviolet radiation, large day–night temperature variation, and frequent high-wind events, provide a distinctive setting for the migration, dispersion, transformation, and degradation of MPs across environmental matrices. Understanding the distribution, sources, and migration patterns of microplastics on the Qinghai–Tibet Plateau will help facilitate sustainable environmental management, ecosystem conservation, and pollution control in these fragile high-altitude regions. Full article

The construction of the Hainan Free Trade Port (FTP) is guided by the core philosophy of “ecological priority and green development.” To meet the practical requirements of building a “Green and Beautiful FTP,” this study constructed a kernel Normalized Difference Vegetation Index (kNDVI) dataset using Landsat series satellite imagery. By integrating methods including the Mann–Kendall (MK) trend test, Hurst exponent, and coefficient of variation (CV), an in-depth analysis was conducted on the spatiotemporal evolution characteristics and trends of growing-season vegetation in Hainan Island from 1994 to 2023. Additionally, the Extreme Gradient Boosting (XGBoost) model and the SHapley Additive exPlanations (SHAP) interpretation method were employed to quantitatively unravel the driving mechanisms of climatic factors and human activities on kNDVI variations. The results indicate that: (1) Over the past three decades, the overall kNDVI of Hainan Island has exhibited a significant upward trend, characterized spatially by an evolution pattern of “stable recovery in the central region and localized degradation along the coast.” (2) The vegetation evolution demonstrates strong persistence and is highly consistent with community stability. The high stability in the central mountainous areas stems from a superior natural background and strict ecological protection; the transition zone is jointly influenced by vegetation types and anthropogenic management; meanwhile the coastal areas exhibit significant degradation characteristics driven by high-intensity human disturbances. (3) The analysis of driving mechanisms reveals a complex control logic of “topographical foundation—human reshaping—extreme climate triggering.” Static topographical factors, such as elevation and slope, occupy an absolute dominant position; human activities, represented by rubber plantation expansion and urbanization, exert a bidirectional reshaping effect characterized by “inland greening and coastal suppression”; furthermore, extreme drought and high temperatures in the later stages of the study demonstrated a significant pulse-like impact, exacerbating the risks of short-term climatic stress. This study clarifies the core patterns of vegetation evolution in Hainan Island, validates the effectiveness of ecological policies, and provides a quantitative scientific basis for ecological conservation and sustainable development in tropical island regions. Full article

Atmospheric PM₁₀ was investigated across Campania, southern Italy, during August 2024 to assess its elemental composition and probable sources. In total, 132 daily samples were collected at six ARPAC sites representing harbor, traffic, industrial, school, and regional-background conditions. PM₁₀ concentrations ranged from 2 to 72 µg m⁻³, with the highest and lowest values recorded at the traffic and background sites, respectively. Elemental composition was determined by particle-induced X-ray emission and complemented by SEM–EDS. Elemental-based Positive Matrix Factorization (PMF) resolved six profiles, tentatively assigned to S-rich secondary aerosol, Cl-rich marine aerosol, mixed combustion/industrial emissions, Cu-rich traffic emissions, Ca–Sr-rich road dust, and Pb–Zn-rich waste combustion. At the industrial site, the three anthropogenic profiles together represented 74% of the apportioned mass. Traffic-related, marine, and S-rich secondary aerosol represented 49%, 65%, and 30% at the traffic, harbor, and background sites, respectively. SEM–EDS identified representative irregular S–K-rich and Ca-rich particles, crystalline Na–Cl-rich particles, and fine spherical metal-rich particles. Conditional probability function and trajectory analyses indicated local and regional influences, including a possible secondary sulfate contribution from the Mount Etna region. As the PMF analysis relied exclusively on elemental data, these source assignments should be regarded as indicative rather than definitive. Full article

River avulsion, the sudden relocation of a river channel to a new course from the parent channel, is a geomorphic process with direct implications for floodplain evolution, ecosystem dynamics, and infrastructure vulnerability. This review article discusses how sandbar migration acts as a precursor to avulsion by altering hydraulic geometry, redirecting flow paths, modifying sediment transport patterns, and affecting the development of incipient channels. The morphodynamic evolution of sandbars, influenced by sediment supply, flow regime, vegetation, and anthropogenic influences, such as dams and sand mining, plays a central role in creating avulsion. Different methods, such as field measurements, remote sensing imagery (including multispectral, SAR, LiDAR and UAV), physics-based numerical models, machine learning, and deep learning techniques, which are used to evaluate river sandbar and river avulsion, are also thoroughly evaluated for efficacy and fit for purpose. Future research should focus on combining different data sources and creating a model that understands vegetation–sediment–flow feedbacks, sediment sorting process, anthropogenic impacts and extreme climate change impacts on channel evolution. Full article

In this study, we aimed to investigate the occurrence, characteristics and temporal dynamics of microplastics (MPs) in the gastrointestinal tracts of saddled seabream (Oblada melanurus) from Izmir Bay (Eastern Aegean Sea). Sampling was carried out monthly during a one-year period (March 2021–February 2022) and MPs were identified by stereomicroscopy and ATR-FTIR spectroscopy. Microplastics were identified in 115 of the 180 examined individuals, representing an overall frequency of occurrence (FO) of 63.89%. A total of 298 microplastic items were recovered, corresponding to a mean abundance of 1.66 ± 0.35 items individual⁻¹ across all examined fish (N = 180) and a mean intensity of 2.59 ± 0.41 items/individual among positive individuals (N = 115). The highest occurrence (100%) was observed during December. Fibers were the most abundant morphotype (58%) followed by fragments (39%). Black (56%) and blue (20%) particles were the most abundant colors. Size distribution was 105–4678 µm with mean length of 1370.08 ± 1122.74 µm. The most frequently identified polymers were polyethylene terephthalate (PET, 29%), polyethylene (PE, 19%) and polypropylene (PP, 18%). We did not find any significant relationships between MP abundance and fish size, weight or sex (p > 0.05). The study area was classified into high-risk category (Category IV) based on the value of Polymer Hazard Index (PHI) (129.52). The results show temporal variability of MP ingestion, likely influenced by seasonal conditions and anthropogenic activities. Full article

This study evaluates whether existing long-term monitoring data are sufficient to distinguish natural background concentrations from anthropogenic influences on chemical river water quality in Lake Sevan basin. A comprehensive dataset covering physicochemical parameters, nutrients, and trace metals was analyzed for nine major tributaries with different geological settings and land-use characteristics. Multivariate statistical analysis was applied to identify baseline conditions and deviations attributable to human activities. The results indicate that water chemistry is primarily controlled by lithology and hydrological regime, particularly in minimally impacted headwater regions. In contrast, elevated concentrations of nutrients (e.g., nitrate and phosphate) and selected trace elements were associated with agricultural runoff, urban discharge, and localized industrial inputs. Spatial patterns reveal clear gradients of increasing anthropogenic impact downstream and in densely populated sub-basins. The study also demonstrates that, while the current monitoring network is suitable for assessing the overall chemical status of rivers, it is less effective in defining natural background levels and quantifying individual pollution sources due to limited upstream reference conditions. Overall, this approach provides a scientific basis for improved water quality management and policy implementation in the Lake Sevan basin. The findings highlight the importance of integrating long-term monitoring data with statistical tools to support sustainable watershed management in vulnerable catchments. Full article

The management of estuarine ecosystem sustainability is a complex problem that requires models that are physically sound, socially meaningful, and interpretable from a mechanistic standpoint. Even though classical AI has demonstrated promise in environmental forecasting, black-box models typically fall short of meeting basic conservation requirements or accounting for anthropogenic stresses that alter water quality. This work introduces a novel framework based on Deep Physics-Informed Neural Networks (Deep PINNs) to predict the dynamics of dissolved oxygen (DO) in the Bouregreg Estuary (Morocco). We advance baseline standards by directly integrating the non-linear advection–diffusion–reaction (ADR) transport equations into the loss function of a deep residual architecture (ResNet with 12–20 layers). This integration ensures that the model takes into account two important aspects of estuarine hydrodynamics: gravitational circulation and the salt wedge effect. The incorporation of a socio–hydro–physical nexus, which uses regional water-pricing indices and urban wastewater discharge volumes from the Rabat-Salé municipal area $(\sim \mathrm{120,000} {\mathrm{m}}^3/\mathrm{d}\mathrm{a}\mathrm{y})$ as proxy variables for anthropogenic pressure, is a unique aspect of this work. The Deep PINN achieves a better coefficient of determination ($R^2=0.998$) and a Nash–Sutcliffe efficiency ($\mathrm{N}\mathrm{S}\mathrm{E}=0.997$), outperforming the traditional ANFIS and ANN baselines by $89.1\%$ in terms of predictive error reduction ($\mathrm{R}\mathrm{M}\mathrm{S}\mathrm{E}=0.041\pm 0.002 \mathrm{m}\mathrm{g}/\mathrm{L}$). In situations where unconstrained data-driven models fall short, the framework exhibits physical robustness in capturing vertical DO stratification in addition to numerical accuracy. Urban effluent volumes have a significant impact on predictive variance, accounting for 28% of the model internal attribution—more than the relative influence of thermal solubility, according to mechanistic feature attribution analysis using SHAP (Shapley Additive exPlanations). Finally, exploratory management scenarios suggest that summer hypoxia could hypothetically be mitigated through a $20\%$ reduction in discharge volumes. This study bridges the gap between scientific modeling and policy implementation by providing a physics-consistent digital twin framework for environmental stewardship in support of UN SDG 6 and Morocco’s National Water Plan. Full article

Restoration of natural sterlet (Acipenser ruthenus) stocks in the transboundary Irtysh River, shared by China, Kazakhstan, and Russia, is of critical importance for biodiversity conservation and represents a strategic priority for sustainable management of transboundary aquatic resources in all three countries. Over the past two decades, sterlet abundance and occurrence in the river have remained low, indicating an unfavorable population status. The Irtysh sterlet population is likely influenced by a combination of habitat degradation, fragmentation of spawning habitats, alterations in the hydrological regime, and increasing anthropogenic pressure. This study summarizes archival and recent data on sterlet catches, biological condition, and habitat characteristics within the Irtysh River basin. Hydrological and hydrochemical parameters, spatial distribution of catches, and the size–age structure of the population were analyzed. The results revealed a localized distribution pattern of sterlet, with the aggregation index reaching I ≥ 1 in some cases, indicating an uneven spatial distribution of individuals. Such aggregation patterns may partially reflect the presence of ecologically important habitats and provide a basis for future conservation planning and targeted monitoring, although this relationship could not be confirmed within the scope of the present study. A decline in the proportion of older age groups and deterioration of key biological indicators suggest weakening natural reproduction. The study initiated the establishment of a replacement broodstock and formed an initial broodstock of 34 sterlet individuals collected from the wild. This provides a foundation for future artificial propagation and the recovery of the endangered Irtysh River sterlet population. Full article

Shansha Bay, southeastern China, is a typical semi-enclosed bay facing intense anthropogenic pressure, with mariculture production reaching approximately 660,000 tons annually, predominantly driven by the large yellow croaker (Larimichthys crocea) industry. To assess how these pressures influence biodiversity detection, we employed eDNA metabarcoding targeting the 12S rRNA gene to survey fish diversity across 10 sites, integrating both surface water and sediment matrices. A total of 40 species belonging to 16 orders, 27 families and 32 genera, were identified. Among them, L. crocea, Bostrychus sinensis, Clupanodon thrissa and Siganus fuscescens are the dominate species, which comprised over half of all OTUs. Comparison with historical trawl surveys revealed 30 newly recorded species, including the Japanese eel (Anguilla japonica) and oarfish (Regalecus glesne). Alpha diversity was low (Shannon: 0.69–1.93), with significant spatial disparities driven by freshwater runoff and hydrodynamics. While eDNA effectively captured the dominance of cultured species like L. crocea, the extreme biomass signal poses challenges for detecting wild populations. Our findings underscore that a multi-matrix eDNA approach is crucial for accurate biodiversity assessments in aquaculture-dominated coastal ecosystems, although distinguishing wild stocks from aquaculture-derived DNA remains a critical methodological hurdle. Full article

Seawater intrusion (SWI) represents an increasingly critical challenge for coastal groundwater systems, with particularly pronounced impacts observed along the Indian coastline. Coastal aquifers constitute a vital freshwater resource supporting domestic, agricultural, and industrial demands. This study evaluates SWI vulnerability along the entire Indian coast, extending from Gujarat to West Bengal, covering approximately 7517 km of shoreline and up to 100 km inland. The assessment applies the GALDIT vulnerability framework that combines several hydrogeological and hydrochemical criteria such as groundwater occurrence, aquifer hydraulic conductivity, depth to groundwater, distance from shoreline, hydrochemical data, and groundwater quality data. We also assessed the intrusion of existing seawater, shoreline location, and aquifer thickness. However, conventional vulnerability assessments are inherently static and often fail to capture anthropogenic influences. To address this limitation, the present study integrates multi-temporal land use and land cover (LULC) datasets derived from ESA WorldCover remote sensing data for the period 2017–2024. Incorporating LULC dynamics enables a more comprehensive evaluation of the impacts of urban expansion and agricultural intensification on coastal susceptibility to SWI. Accordingly, a modified GALDIT-LU framework is developed to assess the spatiotemporal evolution of coastal vulnerability. The outcomes suggest that huge parts of the Indian coastline are vulnerable to moderate or very high classes, with the very high vulnerability class growing from 13,295 km² in 2017 to 38,257 km² in 2024, a 188% increase in vulnerability over the course of seven years. Groundwater chloride concentrations from Central Ground Water Board (CGWB) monitoring well locations have been used for validation over the proposed assessment, and show good spatial agreement between areas identified as high vulnerability and the spatial distribution of groundwater salinity for all three assessment periods, lending support to the robustness and predictive power of the proposed groundwater salinity assessment. The findings carry direct implications for the United Nations 2030 Agenda, demonstrating that the identified vulnerability patterns intersect with critical targets related to clean water and sanitation, food security, public health, climate action, and poverty reduction along one of the world’s most densely populated coastlines. Full article

Elucidating the multi-scale driving mechanisms of the spatiotemporal distribution of soil pH is critical for regional soil ecological regulation and the preservation of cultivated land fertility. However, systematic elucidation of the multi-scale driving mechanisms of the spatiotemporal distribution of soil pH remains limited. Here, we integrated random forest, XGBoost, and geographically interpretable SHAP (GeoShapley) to systematically investigate the spatiotemporal changes in soil pH and their driving mechanisms across three analytical scales (global, raster, and point-level) before and after high-standard farmland construction, based on 149 paired soil sampling points collected in 2008 and 2023 in Taihe County, Jiangxi Province. The mean soil pH in the study area increased from 5.12 in 2008 to 5.53 in 2023, suggesting mitigation of soil acidification. XGBoost outperformed random forest in both periods, with R² values of 0.71 and 0.67 for the two periods, respectively, and the spatial predictions indicated that soil pH in the western and southeastern regions increased following high-standard farmland construction. At the global scale, feature importance based on XGBoost indicated that climate contributed most to soil pH variation in both periods, followed by anthropogenic activities. At the raster scale, GeoShapley revealed a shift from a combination of anthropogenic activities and climate in 2008 to an interplay among climate, vegetation, and topography in 2023, suggesting a decreasing influence of anthropogenic disturbance. At the point level, the factors primarily influencing soil pH shifted from topographic and anthropogenic ones in 2008 to topographic and climatic ones in 2023, regardless of whether the sampling points exhibited low or high pH values, further corroborating the diminishing role of anthropogenic influence. Interaction analyses indicated that topography and vegetation consistently modulated the effects of anthropogenic and climatic factors throughout the study period, suggesting that these two factors were consistently associated with soil pH dynamics across the study area. In summary, this study provides a scientific basis for the targeted improvement of cultivated land fertility and the formulation of differentiated soil management strategies for high-standard farmland in the hilly regions of southern China. Full article

Hydroclimatic evidence is often carried too directly from global-scale attribution studies into local water-resources decisions, despite important differences among variables, methods, and spatial scales. This critical narrative review examines how climate variability, statistical trends, detection, attribution, non-stationarity, and risk should be distinguished when interpreting changes in precipitation, drought, streamflow, floods, groundwater, and water availability. The review compares global assessments, Mediterranean studies, and selected local examples to clarify what each line of evidence can—and cannot—support in adaptation planning. Human influence on global warming is unequivocal, and increases in atmospheric evaporative demand are well supported across many regions; anthropogenic influence has also been detected in several large-scale water-cycle responses. Historical changes in precipitation, river flooding, groundwater, and local drought remain spatially heterogeneous because internal variability interacts with circulation, storage, landscape properties, abstraction, infrastructure, and demand. Statistically significant trends do not by themselves establish hydrological importance or causation, while non-significant local trends do not imply an absence of operational risk. On this basis, the review proposes a scale-aware way of matching hydroclimatic evidence with system vulnerability and the degree of commitment involved in adaptation. Low-regret and adjustable measures can address current vulnerabilities under uncertainty, whereas costly, long-lived, or difficult-to-reverse interventions require stronger local evidence and stress testing across plausible futures. Full article

Inland rivers in arid regions are important water resources that support ecosystem stability and human activities. This study comparatively investigated the hydrochemical characteristics, controlling factors, and irrigation suitability of six glacier-fed inland rivers along the southern margin of the Tarim Basin using hydrochemical analysis, Gibbs and Piper diagrams, ion-ratio analysis, principal component analysis (PCA), and PHREEQC inverse mass-balance modeling. The six rivers exhibited distinct hydrochemical characteristics despite their common origin in the Kunlun Mountains. Carbonate weathering dominated the Bostan and Nur rivers, while the Kaxi River exhibited relatively stable hydrochemical characteristics mainly associated with rock weathering. In contrast, evaporite dissolution and evaporative concentration exerted stronger influences on the Uruksayi and Buzang rivers, which also showed more pronounced longitudinal variations in major ion concentrations. The Keriya River showed an overall transition from silicate-weathering-dominated conditions in the upper reaches toward stronger evaporite dissolution and evaporative concentration downstream. PHREEQC inverse mass-balance modeling suggested that halite dissolution, gypsum dissolution, dolomite dissolution, calcite precipitation, and cation exchange contributed to the hydrochemical evolution of the Keriya River. Several abrupt variations in ion concentrations were observed along the river courses, suggesting that localized processes, including tributary mixing, groundwater inputs, or potential anthropogenic influences, may contribute to these hydrochemical changes. PCA extracted two principal components explaining 86.0% of the total variance. PC1 (70.5%) represented overall ion enrichment and mineralization, whereas PC2 (15.5%) reflected carbonate-related hydrochemical variations. Irrigation suitability assessment showed that all rivers exhibited low sodium hazards, while salinity was the main factor limiting irrigation suitability in the middle and lower reaches of the Keriya River and in the Uruksayi and Buzang rivers. This study improves the understanding of hydrochemical evolution and water quality assessment of arid inland rivers and provides scientific support for sustainable water resource management and oasis ecosystem protection in the southern Tarim Basin. Full article

Soil formation in post-mining areas is strongly influenced not only by parent material but also by the vegetation introduced during reclamation. Tree species affect pedogenic processes through litter input, root activity and associated microbial communities. This study investigates soil development in reclaimed post-mining landscapes, focusing on the combined influence of tree species and substrate properties. Two forest sites in Poland were analysed: Szczakowa (former open-pit sand mine) and Bełchatów (lignite mine spoil heap), 30–40 years after reclamation and afforestation with four dominant species: silver birch, European larch, Scots pine and red oak. Differences in soil development were observed among tree species. Stands with deciduous trees (birch and oak) were generally associated with clearer horizon differentiation, higher soil organic carbon and nitrogen content, and more pronounced iron redistribution compared with coniferous stands. The mean thickness of the combined organic-rich surface horizons was 12.4 cm at Szczakowa and 10.8 cm at Bełchatów. Coniferous species were more often linked with soil acidification and early stages of podzolisation-like processes, particularly in sandy substrates, whereas soils under deciduous species showed features related to brunification and organic matter incorporation. The study also included a comparison of soil classification systems, indicating that the World Reference Base for Soil Resources (WRB) offers a flexible framework for describing young and anthropogenically transformed soils compared with traditional national classifications. From a sustainability perspective, the results highlight that strategic species selection during reclamation, specifically promoting birch on sandy substrates and oak on heterogeneous technogenic substrates, enhances soil organic carbon accumulation, nutrient retention and iron cycling, thus contributing to the long-term restoration of ecosystem services on degraded post-mining landscapes. Full article

eDNA metabarcoding provides distinct benefits—including non-invasiveness, cost-effectiveness, and high detection sensitivity—that make it particularly appropriate for aquatic ecosystem conservation and fisheries management. An environmental DNA (eDNA) metabarcoding survey was performed in the Cuijiang River to assess the feasibility of this technique for fish diversity monitoring. Fish diversity was evaluated through water collection, eDNA extraction and purification, and subsequent bioinformatics analysis. Our results revealed that the surveyed river section harbours at least 36 fish species, belonging to 30 genera, 13 families, and 6 orders. The fish community was numerically dominated by Cypriniformes. Notably, invasive alien species represented a relatively high proportion (24.72%) of the total operational taxonomic units (OTUs). Alpha diversity indices showed spatial heterogeneity among the monitoring sites, which is likely influenced by anthropogenic activities, land-use patterns, and hydrological connectivity in the sampling areas. Overall, eDNA metabarcoding proves to be an effective approach for fish diversity assessment and can serve as a valuable supplementary tool to conventional methods, with particular utility for the early detection of elusive and invasive species. We therefore recommend its incorporation into ongoing and future aquatic monitoring and conservation frameworks to strengthen early detection, habitat management, and biodiversity protection, thereby offering essential baseline data for future conservation and management of local fish diversity. Full article