Search Results (445)

This study develops an objective attribution framework, integrating a two-step K-means clustering procedure with a random forest algorithm, to classify the weather systems responsible for high winds over the mid- and lower reaches of the Yangtze River from 2020 to 2023. The analysis utilizes hourly automatic weather station observations, ERA5 reanalysis, and merged precipitation data. Four dominant HW types are identified: cold-air (CAHWs, 40.3%), tropical-cyclone (TCHWs, 27.9%), convective-system (CSHWs, 22.2%), and a residual “other” category (9.6%). Three main types exhibit distinct spatiotemporal distributions and environmental characteristics. CAHWs occur mainly in spring, autumn, and winter, concentrated in three sub-regions within the terrain channel or above the lake surface. CAHWs are characterized by non-precipitating northerlies associated with deformation frontogenesis and modulated by boundary layer processes, including terrain channeling and surface friction. TCHWs are confined to coastal areas in July and September, primarily controlled by tropical cyclone motion and land-sea distribution. CSHWs peak in afternoons from March to October and can be further divided into precipitating (PCSHWs, 40.3%) and non-precipitating (NPSCHWs, 59.7%) types. NPCSHWs typically occur in precipitation-free zones within 50 km of convective systems producing moderate to heavy rainfall, whereas PCSHWs form in smaller convective systems along the periphery of precipitation regions rather than within heavy-rainfall cores. PCSHWs are associated with higher instability, stronger low-level shear, and weaker inhibition than NPCSHWs, indicating a more organized convective environment. Full article

Coastal construction projects often require excavation below the water table, where tidal variability and urban infrastructure generate complex groundwater conditions. This study presents a numerical simulation of water table dynamics in a coastal urban area of Mazatlán, México, influenced by tidal forcing, a lake, and an impermeable seawall. Six critical scenarios were modeled using MODFLOW 6 and ModelMuse interface, covering the period from November 2023 to April 2024. The scenarios correspond to astronomical tide events during the new moon phase, when maximum and minimum tide levels occurred within 24 h. These conditions are related to the highest piezometric levels observed in field. Model calibration was based on 18 field observations collected at 09:00, 12:00, and 15:00 across the selected dates. Model outputs closely matched the field observations, with a root mean square error (RMSE) of 0.056 m, and a mean absolute error (MAE) of 0.049 m. Although the differences are minimal, they reflect short-term variability and limited fluctuation during calibration. However, the full monitoring period showed groundwater levels ranging from −0.10 to 0.53 m above mean sea level (masl), emphasizing the importance of understanding short-term dynamics. This modeling approach supports construction planning, helping to anticipate risks and promote better and informed construction practices. Full article

Small Mediterranean coastal lagoons are sensitive sedimentary environments where basin morphology, hydrodynamic processes, and inherited coastal structures interact to control sediment dispersal. This study investigates modern sedimentary patterns in Lake Porto Vecchio, a shallow coastal brackish pond within the Oliveri–Tindari lagoon system (NE Sicily, Italy), by integrating grain-size statistical and petrographic analyses, and morpho-bathymetric data. A total of 115 surface sediment samples were collected from the coastal pond’s shallow bottom, shoreline, adjacent beach, and shallow marine sector. Grain-size distributions were analyzed using mechanical sieving and laser diffraction, and textural parameters were calculated following Folk and Ward’s formula. Results reveal a well-defined spatial organization of siliciclastic sediments characterized by a grain-size gradient from gravelly coarse-grained sands along the shallow marginal platform to fine-grained sands and silts toward the deeper central basin. This pattern reflects a progressive decrease in hydrodynamic energy from the lagoon margins toward the basin depocenter. A partially lithified beachrock belt forms a shallow platform controlling sedimentation, trapping coarse sediments along the margins while promoting the accumulation of finer fractions in the inner basin. Grain-size discrimination diagrams further distinguish lagoonal sediments from adjacent marine deposits, highlighting the effectiveness of classical statistical approaches in reconstructing modern sedimentary processes. These results support a conceptual model in which inherited beachrock platforms act as key morphological control on sediment architecture in microtidal coastal lakes. Lake Porto Vecchio, therefore, represents a useful modern analog for interpreting similar lagoonal deposits preserved in the Quaternary sedimentary record. Full article

Freshwater ecosystems are increasingly threatened by eutrophication and other anthropogenic and climate-driven pressures that undermine ecological functioning and biodiversity. This study evaluates the transferability of a GIS-based multi-criteria decision analysis (GIS–MCDA) framework with Fuzzy Analytic Hierarchy Process (F-AHP), originally developed for a shallow coastal lake, to a morphologically distinct deep upland lake (Lough Tay, Ireland). Monthly in situ measurements at a single monitoring point in 2024 were analysed together with meteorological variables using Spearman rank correlations. Because spatial interpolation of in-lake water quality parameters was not feasible, eutrophication susceptibility was mapped using four external spatial drivers: distance from water resources (River Cloghoge inflows), land-based nitrogen export potential, distance from environmental pollutants represented by the transportation network, and a wind exposure index derived from a DEM and wind-rose analysis. Criteria were standardized with fuzzy membership functions, weighted using F-AHP (consistency index 0.056), and aggregated using weighted linear combination at 25 m resolution. The resulting Eutrophication Susceptibility Index (ESI) ranged from 0.18 to 0.81, indicating generally moderate to good conditions, with higher ESI values concentrated in the northern lake sector near inflow zones. The results demonstrate that GIS–MCDA can be adapted to lakes with limited monitoring by relying on external drivers, providing a spatial proxy for susceptibility rather than measured trophic status. Full article

Shoreline change detection from remote sensing imagery remains challenging in environments subject to water level fluctuations, as remotely sensed shoreline positions reflect instantaneous hydrodynamic states rather than true geomorphic change. In the Great Lakes, seasonal and short-term water level variations can produce apparent shoreline shifts unrelated to sediment dynamics. Reliable calibration with bathymetry and water level data can mitigate this effect, but such data are often unavailable or difficult to obtain for many coastal and lacustrine systems worldwide. To address this limitation, we proposed a morphology-based framework that quantifies geometric change between successive shoreline curves using a discrete Fréchet distance, a modified Euclidean distance and a Union distance metric. Rather than relying solely on cross-shore displacements, the approach leverages shape similarity to differentiate water-level-driven shifts from true morphological change. We evaluated the framework across three spatial scales (100 m, 500 m, and 1000 m) along 125 km of southwestern Lake Michigan coastline using 2010 and 2020 aerial imagery, benchmarking against water-level-calibrated DSAS erosion hotspots. The Fréchet distance improved monotonically with scale, achieving strong agreement at 1000 m (F1 = 0.84, Spearman $\rho$ = 0.79) but limited reliability at 100 m. While individual morphology-based metrics appeared competitive with or inferior to uncalibrated DSAS at each scale, the union of both distances substantially outperformed uncalibrated DSAS at management-relevant scales (F1 of 0.64 vs. 0.50 at 500 m and 0.79 vs. 0.42 at 1000 m), reflecting the complementary nature of shape-based and displacement-based detection. The Patient Rule Induction Method (PRIM) further identified gentle nearshore slopes and moderate separation from engineered structures as the geomorphic conditions under which the morphology-based and calibrated erosion indicators converged most closely (in-box F1 = 0.92 at 1000 m and 0.72 at 500 m). These results suggest that the proposed framework, particularly the complementary union of both metrics, provides a practical, calibration-free alternative for multiscale shoreline change screening in lacustrine and microtidal, data-limited environments, while local-scale applications still benefit from explicit water-level correction. Full article

The Varna–Beloslav Lake Complex has been subjected to intense anthropogenic pressure over the past century. The excavation of a navigation channel connecting the two lakes with the Black Sea, together with the intensive industrial development in the surrounding area, has led to irreversible alterations in the species composition of the ichthyofauna. This study aimed to document and analyze these changes based on data collected during a four-year survey using a range of ichthyological methods. A total of 28 fish species were recorded, representing approximately one-third of the species historically reported for the complex. Hydromorphological degradation, combined with salinization, heavy ship traffic and pollution, has been identified as the main cause of the observed decline in fish diversity within the system. Full article

6PPD-Quinone (6PPD-Q) is a tire derivative formed by the oxidation of N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD), a commonly used antioxidant and ozone stabilizer in rubber products, and has emerged as a significant environmental concern in recent years. It is widely present in the atmosphere, surface lakes, and soil. The primary routes of exposure to 6PPD-Q are the digestive tract and respiratory tract. Studies indicate that it is a major factor causing acute mortality in coastal coho salmon (Oncorhynchus kisutch). Reports indicate that 6PPD-Q exhibits greater chemical stability and stronger biological toxicity than 6PPD, demonstrating toxic effects across multiple species. 6PPD-Q has been detected in human urine samples, indicating a need for heightened attention to its potential health risks. 6PPD-Q exhibits multi-organ toxicity in organisms, including intestinal, hepatic, neurotoxic, and reproductive toxicity. Its potential toxic mechanisms are associated with oxidative stress and inflammatory responses, and it can disrupt amino acid metabolism, carbohydrate metabolism, and lipid metabolism while interfering with signal transduction pathways by binding to specific receptors. This paper reviews the environmental contamination of 6PPD-Q, explores its potential toxic effects on organisms and underlying mechanisms, analyzes gaps in the current research and future trends, and contributes to a better understanding of its environmental occurrence and biological hazards. Full article

Satellite remote sensing increasingly supports water quality monitoring, yet the temporal transferability of machine learning (ML) models remains insufficiently tested, particularly in coastal shallow lakes subject to hydrological variability. This study evaluates the predictive robustness of satellite-based ML models for electrical conductivity (EC), turbidity (TUR), water temperature (WT), and dissolved oxygen (DO) in Vrana Lake, Croatia. A total of 409 in situ measurements collected during 2023–2024 and 2025 were paired with Sentinel-2 and Landsat 8–9 imagery. Pearson, Spearman, and Kendall correlation analyses were applied for parameter-specific band selection using original, inverse, quadratic, and logarithmic feature transformations. Seventeen regression algorithms were evaluated under six training–testing split strategies, including strict temporal projection. WT exhibited high robustness (R² ≈ 0.90 under temporal projection) due to its strong dependence on thermal bands, while DO achieved moderate temporal stability (R² = 0.51) using log-transformed predictors. EC and TUR demonstrated substantial performance degradation under temporal separation (R² = 0.14 and −4.62, respectively), reflecting sensitivity to distribution shifts. For parameters showing sufficient stability, interpretable band-based retrieval equations were derived using the most strongly correlated spectral predictors. These findings highlight the importance of temporally structured validation and demonstrate that model complexity does not guarantee operational robustness in shallow, dynamically evolving lake systems. Full article

Artificial seawater lakes constructed in estuarine environments are highly susceptible to the intrusion of water containing high concentrations of suspended sediment, which can degrade water quality and threaten ecosystem stability. To clarify the settling mechanisms and sedimentation efficiency under high-turbidity conditions, this study investigated the Baishawan Artificial Lake in the Jiaojiang Estuary, eastern China, through field observations, controlled still-water sedimentation experiments, and a multi-particle size sedimentation efficiency model. Field measurements revealed significant spatiotemporal variability in suspended sediment concentration (SSC), with higher SSC during spring tides than neap tides and a spatial gradient decreasing from the near-estuary zone to the artificial lake and offshore waters. Grain-size analysis showed that suspended sediment was dominated by clay and silt (>98%). Laboratory experiments indicated a two-stage settling process characterized by rapid initial sedimentation followed by gradual stabilization; under high concentration (1.32 kg/m³), SSC decreased by about 85% within 40 min due to concentration-enhanced flocculation, whereas under low-concentration conditions (0.24 kg/m³) approximately 14 h were required to reach the target concentration of 0.01 kg/m³. Model validation demonstrated that the multi-component sedimentation model effectively reproduced the temporal attenuation of SSC. Model application further suggested that when the initial SSC was 0.70 kg/m³ and the water depth was 5.7 m, the sedimentation tank could reduce the SSC to 0.01 kg/m³ within about 16–17 h, with an estimated annual sedimentation volume of ~65,000 m³ and a recommended dredging interval of five years. These results provide quantitative guidance for sedimentation tank operation and sediment management in estuarine artificial lakes and other high-turbidity coastal environments. Full article

Urban wetlands in coastal cities are under growing strain from urban growth, climate change, and governance that is often fragmented. This study evaluates the condition of the freshwater dune lakes located in the Veracruz–Boca del Río–Medellín conurbation in Mexico, a protected corridor made up of 33 dune lakes that is increasingly pressured by urban expansion. We used an interdisciplinary approach that combined ecological monitoring, legal analysis, and participatory management tools. Fieldwork included 24 h monitoring of dissolved oxygen, measurements of Biochemical Oxygen Demand (BOD₅) in representative systems, a diachronic review of the legal evolution of five Natural Protected Areas (NPAs), and community workshops to jointly design interventions. The results showed strong day–night swings in oxygen (4.0–14.8 mg/L) linked to vegetation dynamics, with nighttime hypoxia posing risks for aquatic fauna. BOD₅ ranged from 4.8 to 150.3 mg/L, pointing to severe organic pollution in the most degraded system. The legal review identified repeated patterns of environmental regression, expressed through reductions in protected polygons, the legalization of irregular settlements, and the fragmentation of protected areas through judicial processes. In response, we propose a hybrid management model that brings together riparian restoration, Sustainable Urban Drainage Systems (SUDS), green infrastructure, and participatory monitoring, emphasizing a key 100 m buffer zone. This integrated strategy aims to improve flood regulation, reduce urban heat island effects, and enhance water quality, while also reinforcing community stewardship and legal protection. We conclude that conserving these urban wetlands effectively requires adaptive approaches that connect landscape-scale and local-scale actions, which are essential for climate adaptation in rapidly urbanizing coastal regions. Full article

Urban flooding is prevalent in low-lying, coastal regions, where subtle topographic variation, shallow groundwater, and impervious surfaces govern inundation dynamics. This study evaluates urban flood susceptibility across Miami-Dade County by integrating flood-conditioning factors, including elevation, slope, rainfall, land use/land cover, distance to roads and open water, stream power index (SPI), topographic wetness index (TWI), groundwater depth, and flow accumulation within an Analytical Hierarchy Process (AHP)-based weighted overlay framework. The AHP-derived weights demonstrated strong consistency (consistency ratio = 0.022) and were applied to reclassify each conditioning factor into five flood susceptibility classes—very low to very high. The model performance was evaluated using the Federal Emergency Management Agency (FEMA) flood zone, and the findings demonstrated that the AHP-based framework effectively differentiates flood susceptibility at a fine urban scale, achieving strong predictive performance; area under the Curve (AUC) = 0.85. The results also reveal pronounced spatial variability in flood susceptibility, with northeastern urbanized areas, particularly in Hialeah, Miami Gardens, Miami Lakes, and Downtown Miami, exhibiting higher susceptibility compared to the northwestern Everglades region. Overall, this study presents a robust urban flood susceptibility framework that supports improved flood risk assessment and decision-making in complex urban coastal environments. Full article

Lake Faro (Cape Peloro coastal lagoon, NE Sicily, Italy) is a distinctive Mediterranean coastal lake characterized by the coexistence of a shallow platform and a steep-sided deep basin within a very limited area. This study provides a sedimentological and geological characterization of the present-day lake floor based on grain-size, petrographic, statistical, and GIS-based analyses, with the aim of clarifying the relationship between basin morphology and modern depositional processes. The lake floor is subdivided into two main bathymetric domains. The shallow platform (<10 m water depth) is dominated by modern coarse-grained, very poorly sorted sediments, including gravel and very coarse- to medium-grained sand, deposited under high-energy, low-confinement conditions comparable to beach and open-lagoon environments. In contrast, the deep basin (>10 m water depth) is characterized by modern finer, organic-rich sediments with extremely poor sorting, reflecting lower-energy and more confined depositional conditions. A key new finding is the identification of upper Holocene beachrocks beneath the modern unconsolidated sediments of the shallow platform, which likely exert a significant morpho-structural control on platform development. Overall, the results highlight the strong influence of bathymetry on sediment distribution in coastal lake systems and provide a reference framework for comparable Mediterranean lagoon environments. Full article

Wetlands are among the most threatened ecosystems worldwide, particularly in the Mediterranean Basin, where historical land reclamation and agricultural intensification have profoundly altered natural landscapes and biodiversity. The Ariscianne area (Apulia, southern Italy) represents a highly transformed coastal wetland in which remnants of aquatic vegetation persist mainly within artificial irrigation channels. This study provides the first phytosociological assessment of the aquatic vegetation currently occurring within these channels, with the aim of documenting plant community composition and identifying habitats of conservation interest. Vegetation surveys based on the phytosociological approach were conducted, and plant communities were classified through multivariate cluster analysis supported by expert validation. Five plant associations were identified, belonging to three vegetation classes: Lemnetea (Lemnetum minoris), Potamogetonetea (Zannichellietum palustris, Potamogetonetum trichoidis), and Phragmito-Magnocaricetea (Nasturtietum officinalis, Helosciadetum nodiflori). The distribution of these communities was consistent with subtle hydrological and environmental differentiation within the channel network, although measured differences in water depth were not statistically significant. The Annex I habitat 3150 (“Natural eutrophic lakes with Magnopotamion or Hydrocharition-type vegetation”) was recorded for the first time in this locality, and Potamogeton trichoides was rediscovered after several decades, highlighting the ecological relevance of these relict channel systems. The results demonstrate that artificial irrigation channels, despite their anthropogenic origin, can retain habitat types of conservation interest and function as secondary refugia for wetland vegetation within reclaimed Mediterranean landscapes. This study provides a baseline framework to support future ecological investigations, monitoring activities, and site-specific conservation strategies. Full article

The Great Lakes are the backbone of the economy of eight inland coastal states (Illinois, Indiana, Michigan, Minnesota, New York, Ohio, Pennsylvania, and Wisconsin) in the United States of America. This freshwater source provides unique opportunities for industrial development and recreational activities, which in turn depend critically on the quality of the water. Decades of industrial activities have resulted in the release of PFAS (Per- and Polyfluoroalkyl Substances) into these freshwater sources, prompting an immediate threat to their sustained operation due to potential human health concerns and ecotoxicological impacts. Recent monitoring and research studies report that all the Great Lakes have concerning levels of PFAS requiring immediate attention. While extensive research has been conducted on water quality, the availability of data sources is not within the reach of many researchers, planners, developers, legislators and policy makers. This research aims to develop a data warehouse that will provide scientific and non-scientific communities with essential information and data related to the presence of PFAS and their sources and spatiotemporal trends. The data warehouse will serve as a repository of data (such as information on events, PFAS compounds, precipitation, microplastics, transport, time, and location; chemical formula and safety datasheets; datasets; and scientific research articles and reports) and fact and dimension tables that will store pertinent PFAS data for water research communities. With this data stored in one application, community members will be able to investigate and recommend better solutions to the challenges related to PFAS presence and remediation in the Great Lakes Basin. This research and the data warehouse development steps will also address the knowledge and data gaps that are not typically addressed by other modeling approaches. Full article

Lake Van (Eastern Turkey), the world’s largest soda lake, represents a unique geochemical environment characterized by high alkalinity (pH about 9.7) and a complex hydrochemistry, driven by deep hydrothermal input and extreme evaporative processes. This article evaluates mineralogy, minor elements, and Rare Earth Element (REE) geochemistry of coastal stromatolites from 11 sites, to discriminate between endogenous chemical signals and terrigenous contamination. Results identify two distinct lithological groups: a chemically pure authigenic end-member (CaCO₃ > 85%), overprinted by a significant siliciclastic detrital contribution, rich in SiO₂, Al₂O₃, and Fe₂O₃. Authigenic samples successfully preserve the primary hydrothermal signature, exhibiting marked Heavy Rare Earth Element (HREE) enrichment and superchondritic Y/Ho ratios (=35), inherited from the stability of dissolved dicarbonate complexes, such as [REE(CO₃)₂]⁻, which favor HREE solubility and uptake into the carbonate lattice. Conversely, the significant detrital contribution is highlighted by a robust correlation between REE and lithogenic proxies (Al-Si-Fe). Furthermore, the non-CHARAC behavior observed in Y/Ho and Zr/Hf twin pairs effectively distinguishes biogenic-chemical precipitation from detrital inputs. These results highlight the effectiveness of REE geochemistry as a proxy to filter out lithogenic overprints and accurately isolate the primary hydrochemical record of carbonate stromatolites. Full article