Search Results (1,440)

Long-term morphodynamic responses to large ports are difficult to quantify when historical observations cover different periods, spatial domains, and engineering interventions. At Ashdod Port, on the Mediterranean coast of southern Israel, previous studies documented individual stages of coastal change, but the cumulative response to six decades of port development remained unresolved. This study reconstructs the Ashdod coastal system from 1957 to 2025 using historical and modern bathymetric–topographic surveys, shoreline analysis, and intervention-adjusted sediment balances. During 1965–1995, approximately 4.50 × 10⁶ m³ of sand accumulated within the ~2.5 km sector immediately south of the main breakwater (MBW), while a comparable deficit developed north of the port. Following construction of Ashdod Marina (1995–1997), accumulation became distributed across the southern sectors, while erosion persisted north of the port and extended farther downdrift. For 1965–2021, intervention-adjusted balances were +7.859 × 10⁶ m³ south and −7.208 × 10⁶ m³ north of the port, corresponding to +140 and −129 × 10³ m³/yr, respectively. Their similar magnitude and opposite signs constrain the long-term morphological response to interruption of the predominantly northward sediment-transport system but do not constitute a direct LST estimate. Successive port expansions extended the MBW head from ~15 to ~25 m water depth, across most of the sandy inner-shelf domain extending to ~30 m. North of the port, substantial sediment losses were accompanied by limited shoreline retreat, showing that shoreline change alone underrepresents the submerged response. Despite artificial northward transfer of ~1.457 × 10⁶ m³ since 2000, the downdrift deficit persisted. Historical accumulation south of the port should therefore not be equated with a presently available sand reserve. The record demonstrates the value of multi-decadal volumetric analysis for resolving cumulative port impacts and supporting sediment management on engineered sandy coasts. Full article

This study investigated the biogeochemical processes governing heavy metal sequestration in Laguna Honda, a hypersaline Mediterranean wetland affected by intensive olive cultivation located in the Guadalquivir Basin River (S Spain). A network of sediment samples was analyzed from the wetland using X-ray fluorescence, ICP-MS, and high-resolution electron microscopy (FESEM/HRTEM). Geochemical data were treated with statistical factor analysis. Sediments show significant enrichment of Cu, Hg, and Au due to anthropogenic agrochemical treatments. Mineralogical characterization revealed authigenic pyrite framboids and metallic sulfide nanoparticles (CuS and HgS) within organic-rich sediments, where sequestration is primarily probably driven by the metabolic activity of sulfate-reducing microorganisms (SRMs) under reducing conditions. Additionally, Au enrichment is attributed to mechanical transport and coagulation of pesticide-derived nanoparticles, exhibiting a distinct geochemical correlation with rare earth elements (REEs). We concluded that hypersaline wetlands act as critical environmental sinks, where microbial activity, high organic matter content, and detrital transportation interact to facilitate the immobilization and stabilization of toxic trace elements through the precipitation of low-solubility sulfide phases (Cu and Hg) and the mechanical accumulation of nanoparticles (Au). Full article

This study evaluated the influence of Pseudocnus dubiosus density on the bioremediation of organically enriched marine sediments collected from El Ferrol Bay (Áncash, Peru). A laboratory experimental design was applied, comprising one control treatment without organisms and three treatments with increasing densities of P. dubiosus (27, 41 and 54 individuals per experimental unit), each with three replicates. The physicochemical parameters of the system, sediment organic matter reduction and the organoleptic changes associated with the process were assessed. The results showed that the presence of the organism significantly enhanced organic matter removal compared with the control, which achieved only a 0.97% cumulative reduction, whereas the treatments with organisms reached 34.42%, 40.97% and 43.36%, respectively. In the higher-density treatments, turbidity increased, while nitrate, phosphate and chemical oxygen demand (COD) decreased, suggesting intensified bioturbation, particle resuspension and transformation of organic compounds at the sediment–water interface. Although all evaluated densities produced a favourable functional response, the greatest numerical efficiency was recorded at the highest density. Overall, the findings support the potential of P. dubiosus as a benthic organism for application in bioremediation strategies aimed at coastal ecosystems degraded by organic matter accumulation. Full article

Snowmaking systems are increasingly used to serve winter tourism in mountain regions, yet their role in the environmental dissemination of antimicrobial resistance (AMR) remains poorly understood. Here, we investigated how snowmaking infrastructure affects the transport, retention and reduction of antibiotic residues, antibiotic resistance genes (ARGs) and phenotypically resistant bacteria along two interconnected water chains feeding technical snow production in mountain catchments. Over two winter seasons (2023/24 and 2024/25), we quantified a panel of clinically relevant antibiotics, ARGs and resistance phenotypes in wastewater effluent, intake water, reservoirs, technical snow, aged snow, meltwater and receiving streams; culturable bacteria, resistance phenotypes and ARGs were additionally assessed in reservoir sediments and snow cannon filter material. Wastewater and intake water exhibited the highest antibiotic loads and ARG richness, dominated by fluoroquinolones, macrolides and β-lactam resistance determinants. Reservoirs accumulated substantial amounts of antibiotics but their reduction occurred further along the snowmaking chain. Fresh technical snow still contained multiple antibiotics and ARGs, and harbored resistant Enterobacteriaceae, indicating that snowmaking systems can redistribute AMR determinants into the snowpack. Aged snow, meltwater and receiving streams showed nearly complete loss of antibiotic residues and reduced ARG richness, due to processes of snow transformation and downstream transport. By integrating chemical, molecular and phenotypic data with the technical layout of the infrastructure, we identify specific components as AMR retention hotspots and clarify where barrier functions are most effective. Our findings demonstrate that snowmaking infrastructure can both concentrate and distribute antibiotic residues and resistance determinants in mountain catchments, highlighting the need to consider snowmaking systems in environmental AMR risk assessments and One Health frameworks. Full article

Sedimentary heavy metal background levels vary among lake types in heterogeneous floodplain lake systems worldwide. Uniform regional values may therefore bias contamination assessment. We developed a source–process–sink framework linking lake typology to type-specific geochemical baselines for 91 lakes in the Middle and Lower Yangtze River Plain. Ward hierarchical clustering of 24 indicators spanning freshwater, terrestrial and human landscapes plus two spatial metrics identified four groups: shallow river network (Group I, n = 28), small peri-urban lakes (Group II, n = 20), hill–plain transition lakes (Group III, n = 23) and large river-connected lakes (Group IV, n = 20). Pre-industrial layers of four dated representative sediment cores yielded type-specific Cr, Cu, Pb and Zn baselines. Surface heavy metal enrichment and contamination were assessed using the single-factor pollution index (Pi) and geo-accumulation index (Igeo), respectively. Baselines differed markedly with lake groups, with maximum-to-minimum ratios of 2.18, 3.82, 2.39 and 3.64 for Cr, Cu, Pb and Zn, respectively. Greater catchment development triggered the strongest multi-metal enrichment in Group I: P_i values for all four metals exceeded 1 in 92.9% of lakes. Igeo values for Pb exceeded 0 in 85.0% and 78.3% of Group II and III lakes, respectively. Group IV showed the weakest overall enrichment under lower catchment development. Although P_i values for Pb exceeded 1 in 85.0% of its lakes, no lake reached moderate or higher contamination for any metal. Coupling lake typology with type-specific baselines supports enrichment assessment and differentiated management at the lake group scale in China’s Middle and Lower Yangtze River Plain. Full article

Microplastics (MPs) widely distribute in marine environments and generate severe hazards to marine biota, yet little is known regarding the toxic impacts of aged MPs on benthic invertebrates and their surrounding sediment microbiota. This work aimed to fill this research gap by exploring the comprehensive toxicity of aged polymethylmethacrylate microplastics (PMMA-MPs) toward Urechis unicinctus and its sediment habitat. A 21-day laboratory exposure trial was performed with two PMMA-MP treatments: environmentally realistic low concentration (10 μg/L) and extreme high concentration (1000 μg/L). Aged PMMA-MPs accumulated in the body wall and intestine of U. unicinctus, with markedly higher body wall MPs loads in the high-dose group (p < 0.05). High-concentration PMMA-MPs significantly raised intestinal total protein and triggered intense oxidative stress (p < 0.01), and the Integrated Biomarker Response value rose dose-dependently. Sediment microbial β-diversity was obviously reshaped (p < 0.05), with enriched pathogens including Klebsiella and Enterobacteriaceae under high MP exposure, while the worm’s intestinal α-diversity and core microbiome remained stable, showing host adaptability. This study reveals multi-level toxic outcomes of aged PMMA-MPs on benthic worms and their sediment microhabitat, offering fundamental data to evaluate the ecological risks of weathered MPs in marine benthic systems. Full article

Drainage pipeline environments are typically characterized by darkness, high humidity, water accumulation, sediment deposition, reflective surfaces, and severe occlusions. These challenging conditions make conventional single-sensor inspection methods highly susceptible to environmental interference, resulting in false detections, missed defects, and insufficient reliability in defect confirmation. To address these challenges, this paper proposes a vision–LiDAR–ultrasonic multi-sensor fusion method for defect confirmation in drainage pipeline inspection. The three sensing streams are processed in parallel rather than using visual detection as the exclusive trigger: the vision branch performs high-recall screening of apparent defects, the LiDAR branch continuously evaluates geometric anomalies in spatially indexed point-cloud segments, and the ultrasonic branch independently evaluates wall-thickness and echo anomalies along the valid probe-contact path. Candidate regions proposed by any branch are merged through timestamp-, odometry-, and coverage-aware spatial association, after which all available visual, geometric, and acoustic evidence at each union candidate is mapped to basic probability assignments and fused using reliability-constrained Dempster–Shafer evidence theory. The five-run evaluation on the fixed 105-group test subset (18 defects and 87 non-defects) gives the proposed method an Accuracy of 97.7 ± 0.5%, Precision of 93.4 ± 2.2%, Recall of 93.3 ± 2.5%, F1-score of 93.3 ± 1.5%, and false-alarm rate of 1.4 ± 0.5%. Under the same test protocol, the vision-only baseline gives an F1-score of 81.1 ± 2.4% and a false-alarm rate of 3.9 ± 0.6%. These results are calculated from the measured per-group predictions obtained in the experiments. Full article

Mediterranean seagrass meadows, particularly Posidonia oceanica and Cymodocea nodosa, provide important ecosystem services including blue carbon storage, biodiversity support, sediment stabilization, and coastal protection, yet they continue to decline under multiple anthropogenic pressures. This article presents a SEEA EA-aligned natural capital accounting framework for seagrass restoration, developed within the INTERREG EuroMed ARTEMIS project and applied to four pilot sites in Crete, Menorca, Sardinia, and Monfalcone. The sites were selected to represent heterogeneous Mediterranean restoration contexts, including different seagrass species, degradation histories, pressure regimes, and restoration strategies. The methodology applies a seven-step marine natural capital accounting cycle combining ecosystem extent and condition accounts, physical blue carbon accounts, monetary ecosystem service accounts, impact statement accounts, and natural capital balance sheets. Two ecosystem service components are valued: global climate regulation, through blue carbon sequestration and storage, and biodiversity preservation, through a defensive cost approach. Results show strong site-specific variation. Biodiversity preservation dominates total asset values across all sites, while blue carbon is particularly relevant in Sardinia because of its high accumulation rate and carbon stock. A passive restoration scenario for Sardinia shows that pressure reduction and eco-mooring infrastructure can generate substantially larger aggregate values than small-scale active transplantation, mainly because of the larger area addressed. Compared with previous service-specific or broad-scale seagrass valuation studies, this article contributes by linking site-specific ecological monitoring, SEEA EA-compatible accounting outputs, and natural capital balance sheet values within a single framework relevant to marine restoration finance and future nature credit design. Full article

Deep coalbed methane (CBM) is an important frontier for expanding unconventional natural gas reserves and production in China. Significant vertical heterogeneity in coal reservoirs is a primary constraint on exploration and development, and the conventional interval subdivision based solely on burial depth is insufficient for refined evaluation of deep coal reservoirs. This study targets the No. 8 coal seam of the Carboniferous Benxi Formation in the northern part of the eastern margin of the Ordos Basin. Based on core and logging data from wells F and S, this study applies the Milankovitch cycle identification method and uses the short-eccentricity cycle (∼109 kyr) as a working timescale for high-resolution isochronous stratigraphic subdivision of coal seams within a single well. Combined with coal petrology and reservoir property analysis and the Analytic Hierarchy Process (AHP), this study characterizes vertical heterogeneity and quantitatively identifies favorable intervals in the coal reservoir. The results indicate that: (1) the No. 8 coal seam in Well F was divided into three sections, and Well S into two sections. These subdivisions provide a high-resolution cyclostratigraphic framework for evaluating vertical reservoir variations within each well, with higher resolution than conventional depth-based segmentation (spectral confidence > 99%, p < 0.01); (2) coal quality, pore structure, and gas potential vary significantly with depth, and these variations represent geological responses to periodic changes in depositional environment and sediment supply during peat accumulation; (3) AHP-based quantitative evaluation identifies the upper section of Well F (score: 0.336) and the lower section of Well S (score: 0.755) as the favorable targets for the two investigated wells, characterized by good coal quality, favorable pore structure, and high gas storage capacity. These findings provide geological support for refined deep coalbed methane exploration and development in the study area, and also offer a new technical approach for high-precision stratigraphic subdivision of coal reservoirs. Full article

Estuarine intertidal sediments are important sinks for riverine mercury (Hg), yet the effects of organic matter sources and BC fractions on Hg partitioning are still poorly understood. We analyzed sediments from reed-covered and unvegetated flats in the Yangtze Estuary for total Hg (THg), operationally defined Hg fractions, total organic carbon (TOC), total nitrogen (TN), n-alkanes, and BC fractions (char and soot). THg ranged from 60.3 to 228.5 ng g⁻¹, averaging 114.6 ± 38.9 ng g⁻¹. THg was significantly higher in reed-covered sediments and in surface layers, and was positively correlated with TOC and TN (p < 0.01, n = 20), indicating that vegetation-driven organic matter accumulation promoted Hg enrichment. Hg partitioning differed between habitats: reed-covered sediments showed co-dominance of oxidizable Hg and residual Hg, whereas unvegetated flats were dominated by residual Hg (62.0 ± 10.8%), suggesting stronger Hg stabilization in the absence of fresh plant inputs. n-Alkane patterns indicated that vegetation type controlled sediment organic matter composition more strongly than site or depth. While no significant correlations were observed between BC fractions and Hg fractions in individual habitats, soot exhibited significant positive correlations with labile Hg (acid-soluble and reducible Hg) in a depth-averaged analysis of merged surface and subsurface layers (p < 0.05, n = 10), a preliminary signal constrained by the small number of sites, which suggests that soot may facilitate the sedimentary retention of reactive Hg. These results highlight source-specific controls on Hg partitioning beyond bulk TOC. Full article

We tested how depth-linked hydrostatic pressure, sediment temperature, and sediment texture, represented here by grain-size distribution, partition methane (CH₄) between dissolved storage in sediment porewater and ebullitive release in a tropical monomictic lake. Along a shoreline-to-center transect spanning 1.5–7 m depth, we measured 24-h ebullition with replicated inverted funnels over three consecutive days and quantified porewater methane from short cores while recording depth, sediment temperature, grain size, wind, and barometric pressure. Ebullition was greatest at shallow, warmer, sandier sites, whereas porewater methane accumulated at deeper, cooler sites, yielding an inverse spatial pattern of the two phases. Site-level regressions identified sand content as the strongest spatial correlate of bubbling, while porewater methane increased with depth and declined with sediment temperature. Under weak winds and near-constant barometric pressure, ebullition showed no detectable day-to-day variation over the sampled 72-h interval, indicating that between-site differences exceeded short-term temporal variability. Together, these results describe a spatially resolved storage–release pattern consistent with depth-, temperature-, and texture-related controls on methane retention and bubbling in Lake Carioca. Full article

The eastern Pre-Caspian Depression and northern margin of the Tarim Basin are two Paleozoic craton-based basins that were impacted by different late Paleozoic collisional systems—the Uralides and the South Tian Shan. A comparative analysis was performed on their Paleozoic petroleum source rocks as part of this research project. This comparison utilized an identical methodological process across both basins. Data on total organic carbon content (TOC), Rock-Eval pyrolysis and vitrinite reflectance (Ro) were obtained from 15 wells (eight in the eastern Pre-Caspian Depression and seven in the Tarim Basin). In addition to these new datasets, published regional databases and sediment accumulation rates calculated at 40 locations were used. The Pre-Caspian source rocks contained TOC values ranging from 1.9 wt% to 6.0 wt% (average = 3.5 wt%) and had hydrogen indices (HI) ranging from 279 to 500 mg hydrocarbons per gram TOC; they were characterized as oil-prone Type II kerogens and were mature to late-mature (Ro = 0.85–1.40%). The Tarim source rocks contained less TOC (range = 1.2–4.8 wt%; average = 2.6 wt%) and had HI values that were generally lower and highly variable (range = 80–350 mg hydrocarbons per gram TOC); they were composed of Type I–II to III kerogens and were significantly more mature than those found in the Pre-Caspian Basin (range = Ro = 0.80–2.00%), with some areas reaching the dry-gas window. Sediment Accumulation Rates (SARs) were approximately equal in magnitude (maximum SARs ranged from 60 to 64 m per million years) but differed in terms of spatial distribution. While SARs were primarily focused along the southern margin of the Tian Shan mountain range in the Tarim Basin, SARs were relatively evenly distributed throughout the intracratonic eastern Pre-Caspian Depression. Therefore, it can be concluded that the type of orogenic system is responsible for determining when source rocks enter the oil and gas windows, providing a transferable methodology for distinguishing oil- from gas-prone fairways within orogen-flanked cratonic basins. Full article

Stream ecosystems are threatened by chemical contamination and altered vertical connectivity between surface water and groundwater. Vertical hydrological exchanges occur through the porous matrix—comprising coarse surface sediments and the hyporheic zone—which acts as a critical interface for pollutant storage. The Functional Trait (FTR) method, based on oligochaete communities in these two compartments, allows for simultaneous assessment of toxic stress and vertical hydrological exchange dynamics. We applied this method upstream and downstream of four wastewater treatment plants as well as within an impacted tributary and around its confluence zone. Our results, supported by physicochemical analyses confirming effluent-driven pollution, demonstrate marked degradation of biological quality and ecosystem functioning downstream of all discharge points. While coarse surface sediments provided a reliable diagnostic of point-source pollution impacts, investigating the hyporheic zone refined the assessment by identifying site-specific hydrological trends. In one case, it revealed enhanced infiltration dynamics and pollutant accumulation in deep interstitial spaces, while in another, it highlighted groundwater exfiltration as a driver of ecosystem resilience. These findings highlight the FTR method as a robust and flexible tool for water managers. While integrating the hyporheic zone allows for a comprehensive analysis of vertical exchange dynamics and ecosystem vulnerability, focusing on coarse surface sediments alone provides a cost-effective strategy for routine impact assessment and the detection of major exfiltrations reaching the surface. Future research should integrate this biological approach with high-resolution physicochemical monitoring and direct physical measurements of vertical hydrological exchanges. Full article

The pollution of soil by potentially toxic elements in industrial–agricultural transition zones threatens global food security and public health owing to their persistence and bioaccumulation. This study focused on Miyi County, Sichuan (China), a typical region with intensive vanadium–titanium magnetite mining and modern agriculture, and systematically analyzed eight heavy metals and metalloids (Cd, Hg, As, Pb, Cr, Cu, Zn, and Ni) across the categories of atmospheric deposition, irrigation water, agricultural inputs, and soil–crop systems. A rigorous four-stage full-chain diagnosis (concentration–load–ecology–health) was executed to evaluate pollution levels and pathways. The single-factor pollution index identified cadmium (Cd) as the primary pollutant, exhibiting a maximum index of 32.63. The Håkanson potential ecological risk index (RI) demonstrated that Cd was the absolute dominant contributor, reaching a catastrophic single-element risk factor (Ei) of 2191.8 and contributing over 70% to the comprehensive ecological risk. Spatially, soils displayed a distinct point-source cluster diffusion pattern: the northern metallurgical zone was dominated by a Cr-Zn-Cu-Ni industrial assemblage, while the southern zone was enriched in Cd, Pb, As, and Hg. Positive matrix factorization (PMF) source apportionment quantitatively demonstrated that industrial emissions via atmospheric deposition were the primary driver, contributing 55–75% of the total soil exogenous inputs, while agricultural sources (livestock manure and legacy arsenic pesticides) exacerbated localized accumulation. While overlying irrigation water remained safe, channel sediments acted as historical pollution sinks. The human health risk model revealed that children in industrial core areas faced unacceptable carcinogenic hazards, with a lifetime carcinogenic risk (LCR) reaching 5.6 × 10⁻⁴. These highly specific multi-media findings support a macro spatial risk zoning and source interception strategy to decouple economic growth from regional food safety degradation in global transition economies. Full article

Mapping debris flow susceptibility is essential for disaster risk reduction in mountainous regions. This study proposes a spatially enhanced modeling framework to evaluate these mass-wasting hazards. The framework integrates conventional topographic parameters with localized micro-geomorphic indicators to assess susceptibility in Bomi County, Tibet. Extracted geomorphological variables include the Topographic Position Index (TPI), surface roughness, local relief, and flow accumulation. We applied multi-scale moving window operations to explicitly quantify spatial heterogeneity and sediment connectivity. This approach systematically evaluates the influence of localized landscape variations on debris flow kinematics. The Random Forest (RF) algorithm was utilized to construct the spatial susceptibility model, and the area under the receiver operating characteristic curve (AUC) quantified its predictive capability. The proposed framework achieves a high predictive accuracy with an AUC of 0.9434. Feature importance analysis demonstrates that micro-geomorphic variables contribute significantly to the predictions; specifically, TPI and local relief primarily drive the overall classification performance. Furthermore, the multi-scale spatial enrichment enables the model to effectively capture complex physical interactions across the terrain. Ultimately, this methodology provides an objective, spatially explicit tool for mass-wasting susceptibility mapping, offering reliable data to support disaster prevention and risk management in the Tibetan Plateau and similar highly incised alpine ecosystems. Full article