Search Results (5,282)

Climate change and sea-level rise are expected to intensify groundwater salinization in coastal aquifers, yet their relative contributions remain insufficiently quantified. This study developed a MODFLOW–SEAWAT model to compare the combined impacts of future precipitation change and sea-level rise on groundwater salinization in a representative coastal aquifer of the Pearl River Delta (PRD), China. The groundwater-flow component was calibrated using heads from 54 observation wells (R² = 0.878, RMSE = 0.699 m), and the initial salinity field was constructed and spatially evaluated using chloride concentrations from 142 sampling sites. Four scenarios, including baseline, sea-level rise, future precipitation (SSP5-8.5), and their combination, were simulated over 30- and 60-year periods. The scenario comparison indicates that sea-level rise alone slightly increases groundwater salinity, whereas the selected SSP5-8.5 precipitation series produces a stronger response through recharge and freshwater dilution. Under the SSP5-8.5 scenario, the combined area of high-salinity groundwater (Degrees IV and V) after 60 years decreases by approximately 50% compared with the baseline scenario. The combined scenario exhibits salinization patterns similar to those of the precipitation scenario, indicating that precipitation change has a stronger influence than sea-level rise under the selected scenario and hydrogeological conditions of the PRD. These findings suggest that targeted artificial recharge in recharge-sensitive inland transition zones could help mitigate groundwater salinization and support climate adaptation in coastal regions. Full article

Small-scale fisheries are socio-ecological systems in which resource users interact with environmental conditions, fishing regulations, community initiatives, and institutional actors. Understanding how fishers perceive and report these interactions provides information on the social context of fisheries management, although such perceptions cannot substitute for independent assessments of ecological sustainability, behavioural compliance, or governance effectiveness. This study characterized fishers’ environmental perceptions, self-reported fishing practices, participation in environmental education and conservation activities, and perceptions of community and institutional involvement in fisheries management in Tecomate Lagoon, Guerrero, Mexico. A cross-sectional quantitative design was used, and structured questionnaires were administered to 120 active artisanal fishers selected through simple random sampling. Data were analyzed descriptively using frequencies and percentages. Respondents primarily associated the lagoon with economic (49.17%) and food-related (25.83%) functions. Declining water levels (60.00%) and reduced species abundance (40.00%) were the environmental changes reported by respondents. Regarding fishing practices, 94.17% stated that they complied with fishing regulations, and 100% reported releasing organisms below the minimum legal catch size. Environmental training was reported by 95.00% of respondents, while 94.17% reported participation in conservation-related activities. CONAPESCA (80.83%) and UAGro (19.17%) were identified as institutions involved in fisheries-related initiatives. These findings characterize the perceptions and self-reported experiences of surveyed fishers and should not be interpreted as evidence of ecological sustainability, actual behavioural compliance, educational effectiveness, or governance performance. The contribution of the study lies in systematically documenting the resource-user perspective as a component of the social dimension of the fishery. This information provides a descriptive baseline that can complement future ecological, behavioural, institutional, and longitudinal assessments of small-scale fisheries in coastal lagoon systems. Full article

Geochemical proxies in coastal sediments are widely applied to reconstruct past climatic and environmental changes, yet their sensitivity to climate versus localized depositional processes remains debated in dynamic land–sea interfaces. Here, we present major, trace, and rare earth element (REE) data from two Holocene sediment cores (QX01 and QX02) from the western coast of Bohai Bay to decouple provenance, weathering, and hydrodynamic controls. Provenance-sensitive trace element ratios (La/Sc and Th/Sc) and REE fractionation patterns indicate exceptional source stability dominated by the Yellow River and adjacent cratonic catchments throughout the Holocene, eliminating provenance shifts as a confounding variable. Since ~8 ka, an overarching upward increase in raw chemical index of alteration (CIA), accompanied by increasing Al/Si ratios and grain sizes, broadly aligned with the warm and humid Holocene Climate Optimum. Crucially, a highly significant linear relationship between grain size, Al/Si and CIA (R² > 0.78) demonstrates that raw CIA variations were decisively modulated by sea-level-driven hydrodynamic sorting during the Holocene transgression, which shifted the depositional setting from high-energy fluvial regimes to low-energy marine settings, preferentially trapping fine-grained, clay-hosted aluminosilicates with inherently high CIA values. During the late Holocene (~5 ka to present), stabilizing sea-level conditions shifted the raw records into an elevated plateau punctuated by high-frequency fluctuations and localized geochemical anomalies, reflecting a dynamic interface sensitive to episodic fluvial floods or tidal/storm reworking that periodically introduced coarser, quartz-rich detritus. The resulting sorting-corrected CIA_C removes the transgressive clay-trapping artifact and reveals a broad, subdued weathering plateau between ~8 ka and 4 ka BP, consisting with previous Chinese Loess Plateau weathering intensity. These findings highlight that in dynamic marginal-marine sinks, raw silicate weathering indices reflect physical sorting overprints, and hydrodynamic detrending is essential to extract genuine continental paleoclimate signals. Full article

One of the leading drivers of biodiversity loss is land use change due to the ever-increasing demand for food, livestock feed, biofiber, and biofuel. The concept of human appropriation of net primary production (HANPP) was developed to measure the impact that humans have on the environment by accounting for biomass removed from the environment in the form of crops, timber, and grazing. The species–energy hypothesis is an established ecological hypothesis postulating that greater species diversity is correlated with higher levels of energy from plant productivity; this can be measured as net primary production minus harvested HANPP or NPP_ecological. Theoretically, a “biodiversity footprint” could be developed by estimating the reduction in species associated with a volume of biomass extraction, reducing NPP_eco. Achieving this would be an advance in sustainability science. We used the USGS Gap Analysis Project (GAP) dataset for bird species diversity and a unique mapping of HANPP_harvest (from crops, grazing, and timber harvests) at the scale of counties in the conterminous US to test whether HANPP reduces bird species richness. Negative binomial regression finds, however, that HANPP_harvest is only a marginally statistically significant stressor of bird species richness. A secondary measure of NPP_ecological/HANPP_harvest is similarly a marginally significant positive predictor. Consistent with recent literature emphasizing the need to account for spatial autocorrelation in ecological research, however, both HANPP_harvest and NPP_ecological/HANPP_harvest are insignificant predictors of bird diversity in the conterminous US at the county scale when spatial autocorrelation, along with county size and coastal adjacency, are accounted for. We conclude that species richness is determined by a complex set of factors that render using data on HANPP to develop a biodiversity footprint speculative and imprecise in the case of bird species richness in the US. Full article

The discharge of metal-rich mining effluents and waste into marine environments represents a significant environmental challenge, with impacts extending from coastal to deep-sea ecosystems. This study presents a scoping review conducted in accordance with PRISMA-ScR guidelines to identify, classify, and synthesise evidence on the effects of large-scale mining waste disposal in coastal and marine settings. Searches of Web of Science, Scopus, and relevant grey literature sources yielded 147 eligible publications from an initial dataset of 563 records. The evidence reviewed enabled the identification of 81 distinct impacts systematically grouped into nine primary categories spanning physical, geotechnical, hydrodynamic, geochemical, biological, ecological, and socio-economic dimensions. Marine tailings deposits behave as dynamic systems that facilitate the transport of contaminants beyond disposal sites through processes such as plume dispersion, sediment resuspension, turbidity currents, and porewater exchange. Geochemical reactions and geotechnical failures can increase environmental vulnerability, a risk further exacerbated by ocean warming, acidification, and changing circulation patterns. Beyond highlighting the need for precautionary, integrated, and adaptive management approaches, this review provides the first comprehensive global inventory of impact categories and assessment factors associated with marine mining waste disposal, establishing a reference framework to guide future research, environmental management, regulatory evaluations, and industry decision-making. Full article

Sandy littorals are highly dynamic coastal ecosystems but remain poorly studied as wintering habitats for waterbirds in Mediterranean regions. We analysed mid-winter International Waterbird Census data collected along the 100 km sandy littoral of the province of Venice, northern Adriatic Sea (Italy), between 1994 and 2022. The dataset included 28 winter censuses, 70 species, and 150,083 individuals. The assemblage was rich but highly uneven: the Yellow-legged Gull Larus michahellis, Dunlin Calidris alpina, Black-headed Gull Chroicocephalus ridibundus, and Great Cormorant Phalacrocorax carbo accounted for most individuals. Total abundance was stable, despite strong interannual variability, whereas species richness increased significantly. Eco-functional guilds showed contrasting trends: benthic feeders and diving piscivores increased moderately, omnivores declined moderately, whereas the trends of the remaining four guilds were classified as uncertain. The Community Temperature Index did not show a significant directional trend, either for the whole assemblage or after excluding dominant species, suggesting that the observed changes cannot be interpreted as progressive thermophilisation. Overall, the Venetian sandy littoral supports a diverse and functionally heterogeneous wintering bird assemblage, whose long-term changes reflect shifts in community structure and the changing use of open-coast, nearshore, and artificial roosting habitats. The results provide a long-term evidence base for identifying conservation-relevant shoreline sectors, protecting feeding and high-tide roosting habitats, regulating disturbance and beach-management practices, and maintaining continued IWC monitoring of open-coast waterbird assemblages. Full article

Stresses of climate change, urbanization, and segregation make the City of Norfolk in Virginia’s Tidewater region a fitting context for qualitative research into coastal resilience, urban nature, and residents’ perceptions of the environment. Dissertation research into sea level rise and urban development provided a rich environment for developing a practical multi-method system for community-engaged investigations of flooding effects, gentrification, and the loss of urban nature. Multi-method research illuminates social, racial, and economic dynamics in Norfolk residents through participant observation, archival research, semi-structured interviews, and walking interviews. The data generated by archival content analysis and semi-structured interviews can offer insights into citizens’ roles and experiences regarding climate change, urban development and redevelopment, and distressed nature in the city. Innovative use of participant observation and the walking interview can engage with questions of respondents’ personal beliefs about nature and the city, highlighting new possible applications of these methods. This research adds to the literature on the effects of climate change and displacement in Norfolk’s planning policies. It supersedes discussions of the mechanics of climate change to assess a range of residents’ perceptions on their own terms. The article provides a clear framework for engaging with residents around issues on climate, urbanization, and environmental stress. It therefore offers a methodological contribution to the field of qualitative research in coastal climate change science and the human experience of the dynamic, modern city. The article’s findings and methods may not be applicable in rural areas or in areas which are not facing acute climate change. Full article

Safe navigation in coastal waters remains a persistent challenge for conventional grid-based path planning methods, which prioritize shortest-distance optimization while neglecting spatial risk distribution and kinematic trackability. This study proposes a local path planning framework that integrates an integral image-based risk field with kinematic constraints for small vessel navigation in high-resolution coastal environments. The proposed method evaluates local obstacle density through an area-based spatial risk model and employs an integral image structure to reduce risk computation complexity from O(W²) to O(1). A 16-direction node expansion strategy incorporating kinematic filtering and cubic B-spline smoothing was applied to improve maneuvering feasibility and trajectory continuity. Simulation results across two topologically distinct coastal environments, Mokpo–Sinan and Myeongnyang Strait, demonstrated that the proposed framework increased the minimum clearance distance from 20 m to 238.32 m and the average clearance distance from 884.2 m to 1038.3 m relative to the conventional A* algorithm, and consistently outperformed a static buffer-based baseline. The 16-direction search reduced the maximum course change angle by up to 39% and the average course change angle by up to 55% relative to the 8-direction configuration across both environments while maintaining practical computational efficiency. Kinematic feasibility was further verified through curvature-based analysis of the final smoothed trajectories, confirming that the minimum turning radius consistently exceeded the vessel’s theoretical minimum turning radius across all tested configurations. The results demonstrate that the proposed framework can generate risk-aware and kinematically feasible navigation routes using coastline-based occupancy information alone, suggesting potential applicability to coastal autonomous navigation in environments with limited bathymetric data. Full article

Precipitation in Mediterranean regions is characterized by strong intermittency and complex organization across multiple temporal scales, posing challenges for understanding its future evolution under climate change. This study examines projected changes in the multifractal structure of monthly precipitation at 326 stations within the Catalan Internal Basins, using regional climate simulations under RCP4.5 and RCP8.5 scenarios. Multifractal Detrended Fluctuation Analysis (MFDFA) is applied to historical and future series to quantify changes in the central Hölder exponent (α₀), spectral width (W), asymmetry (γ), and a normalized Complexity Index (CI). The results indicate a consistent multifractal reorganization in parameter space dominated by spectral asymmetry. While α₀ and W show slight decreases, γ exhibits larger variations approaching one standard deviation, reflecting a redistribution of fluctuations and a shift in the relative contribution of scaling regimes. Principal component analysis reveals that projected changes are mainly aligned with the asymmetry axis, especially inland, while coastal stations display more multidimensional responses involving all parameters. These findings suggest that projected climate-change responses are primarily expressed through structural changes in the multifractal spectrum and also reveal an excess of extreme deviations without clear spatial organization. This highlights the relevance of combining directional and statistical analyses to characterize the multifractal response. Full article

Mangrove prop root epifaunal communities support coastal biodiversity by providing habitat and refuge for associated sessile species and contributing to larval supply. Yet, regional surveys across latitudinal gradients in southeast Florida remain scarce. Understanding how these communities vary spatially and temporally is essential for forecasting biodiversity responses to environmental change. This study tested how macrobenthic assemblage composition and beta diversity on red mangrove prop roots vary from Key West to Melbourne, Florida. Presence-absence data from 32 sites in four zones were analyzed using beta diversity partitioning, indicator species analysis, and temporal turnover metrics. A strong biogeographic boundary near Palm Beach County delineated a species-rich southern pool, formed by the Florida Keys and Miami-Dade and characterized by tropical sponges. Of the 41 indicator species, 34 were associated with these two southern zones, while neither northern zone had exclusive indicators. Northern beta diversity was dominated by nested subsets of a larger species pool rather than species replacement. Over the three years, only Broward-Palm Beach gained species, while the other three zones lost species, though this was not statistically significant. These findings highlight the ecological significance of the potential biogeographic ecotones and provide a baseline study from which to gain insight into how climate-driven mangrove range expansion may impact coastal biodiversity and ecosystem resilience. Full article

Port-related maritime emissions constitute a significant source of urban air pollution and greenhouse gas emissions, particularly in rapidly developing coastal cities. Within this context, the present study quantifies ship-related emissions at the Port of Casablanca, Morocco’s largest and most strategically important port, and evaluates their associated environmental and socio-economic impacts. A bottom-up methodology was applied to estimate emissions from vessel operations between 2017 and 2021. The inventory integrates vessel characteristics, engine specifications, operational load factors, emission factors, and the duration of maneuvering and hotelling phases to estimate emissions of CO₂, SO₂, NO_x, CO, NMVOCs, PM, PM₁₀, and PM_2.5. The emission inventory was subsequently coupled with damage cost factors to assess the external costs associated with shipping emissions. The obtained results demonstrate that CO₂ was the dominant emitted pollutant, representing approximately 97% of total emissions, whereas NO_x and SO₂ accounted for 2% and 1%, respectively. Bulk carriers emerged as the principal emission source (44%), followed by container vessels (36%), with the highest emission levels observed during 2018–2019, coinciding with increased port operations. Furthermore, the integration of emission inventories with damage cost factors demonstrated that NO_x, although emitted in much smaller quantities than CO₂, exerts a disproportionately higher environmental and societal burden due to its impacts on public health and ecosystem quality. This study provides one of the first integrated bottom-up emission inventories and external cost assessments for a Moroccan port. The proposed framework supports evidence-based decision-making for sustainable port management and demonstrates the need for emission reduction strategies that simultaneously address climate change and air quality objectives. Full article

Coastal defenses under tsunami-like long waves are judged not only by wave attenuation but by their own stability and the hazard left landward, so a porous structure is assessed through several responses at once. OpenFOAM (porousWaveFoam) and FLOW-3D HYDRO are the two models most widely used for such problems, representing the open-source and the commercial approach, and each has an extensive record for solitary waves and for porous structures separately. Which to adopt for a given response is not established, since the two have not been compared where both occur together. Five hydraulic benchmarks were, therefore, reproduced with both, taken as configured in practice, since the differing elements cannot be exchanged by the user. Agreement was decomposed into error components and into the scalars that enter a design check, and each difference was weighed against a combined uncertainty. Neither model is superior across the responses. Across 57 signals, the more accurate one changes with the metric in 81% of cases, and six of thirteen governing comparisons exceed the uncertainty. Some of the largest errors are shared, so changing the model does not remove them, and the cost ordering reverses with the problem size. Model selection should, therefore, follow the target design response, together with a statement of whether the difference exceeds the uncertainty. These findings hold within the configurations tested; extension to random waves remains for future work. Full article

Vulnerable coastal urban margins face overlapping pressures from erosion, climate change, and plastic-waste accumulation. This study presents a screening-level numerical assessment of a hollow modular unit made of a recycled polyethylene terephthalate (PET)–concrete composite, proposed for coastal slope protection and stabilisation in Chucuito, Callao, Peru. A limit-equilibrium baseline indicates that the unprotected slope is marginal to unstable under the site’s seismic demand, motivating the evaluation of a surface-protection concept through a parallel, one-way finite element analysis–computational fluid dynamics (FEA–CFD) framework applied at three slope angles (60°, 53°, 45°). The FEA structural-response screening indicates consistent trends across configurations under an equivalent impact load and the adopted basal restraint. For the hydraulic comparison, inlet velocities of 3, 5 and 7 m/s were anchored to the site-specific Delft3D inundation modelling (site maximum 5 m/s), with a conservative 10 m/s upper bound; relative to a rip-rap reference, the hollow configuration suggests midpoint run-up velocity reductions of approximately 52% at θ = 53° under the conservative scenario and ≈57% at 3 and 5 m/s, falling to ≈25% at 7 m/s with overlapping ranges and the simulated free surface exceeding the crest. The CFD free-surface elevations show order-of-magnitude consistency with an indicative EurOtop-based run-up benchmark used as a consistency check rather than as hydraulic validation. Independent of this hydraulic comparison, the hollow geometry saves ≈ 62% of the material volume relative to an equivalent solid concrete block, valorises ≈ 793 post-consumer PET bottles per unit at a 10% dosage, and suggests a 42–58% embodied-CO₂ reduction relative to the same solid-concrete reference, driven mainly by the hollow geometry rather than by the PET substitution itself. The results are internally consistent but not experimentally validated and are intended as a comparative baseline to guide subsequent experimental and field studies, in line with Sustainable Development Goals (SDG) 11, 12 and 13. Full article

Oyster aquaculture plays a critical role in coastal social-ecological systems by providing ecosystem services such as economic benefits, food security, and environmental regulation; however, multiple biophysical and socio-economic stressors threaten its long-term sustainability. This study operationalizes the seven established resilience principles to identify strategies that enhance the resilience of oyster aquaculture globally. A scoping review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was conducted across Scopus, Web of Science, and JSTOR, yielding 345 peer-reviewed publications (2000–2026) from which 13 stressor categories and 15 mitigation strategy categories were identified. Diseases and pathogens constituted the most documented stressor (24.3%), followed by climate change and ocean acidification (9.9%). Among strategies, the governance, policy, and stakeholder engagement strategy was the most frequently used (12.8%). Classification by resilience principles revealed that managing slow variables and feedback (P3, 30.1%) and maintaining diversity and redundancy (P1, 22.6%) dominated the literature, while broadening participation (P6, 11.0%) and promoting polycentric governance (P7, 4.6%) were least represented, revealing a significant gap in the scientific literature between biophysical and socio-institutional research attention. Context-specific indicators were developed for each principle, providing a replicable framework linking stressors, strategies, and resilience principles applicable to diverse mariculture systems. Full article

Black-sand mining is an under-studied anthropogenic pressure on arid coastal environments, where sparse vegetation and slow natural recovery limit conventional impact assessment. Despite the recent expansion of heavy-mineral extraction along the Mauritanian coast, no spatio-temporal analysis has quantified its effects on land cover and surface-water dynamics in the N’Diago region. We analysed the N’Diago–LGUWYCHICH coastal sector (south-western Mauritania) using three Landsat scenes (2014, 2020, and 2026) in QGIS (free and open-source Geographic Information System), four spectral indices (NDVI-Normalized Difference Vegetation Index, NDWI-Normalized Difference Water Index, BSI- Bare Soil Index, and CI -Coloration Index), supervised Support Vector Machine classification and a 30 m SRTM Digital Elevation Model over a 97.82 ha area of interest. Bare soil dominated the landscape at every date (92.6–95.7%) and vegetation stayed below 7%, indicating that canopy-based metrics underestimate disturbance in this setting. The clearest change was hydrological: an inland water body shrank from 1.02 ha in 2020 to 0.40 ha in 2026, a 60.6% loss. This individual inland water body, measured directly and independently from the NDWI index, is our primary hydrological observation: the wet feature was smaller in the 2026 image than in the 2020 image and was located near the mapped concession areas, but the available data do not establish the cause of this change. Similar bare-soil and colour index values (BSI ≈ 0.23, CI ≈ 0.79–0.80) were observed in the processed images, while residual seasonal and radiometric differences between the Landsat 8 and DOS-corrected Landsat 9 products cannot be excluded; BSI and CI are treated only as candidate or contextual spectral patterns, so any delineation of the disturbed footprint is provisional and requires confirmation from independent field data. This study illustrates a low-cost exploratory workflow that may support preliminary monitoring in data-scarce arid coastal settings, pending validation with denser time series and field observations. Full article