Search Results (1,830)

Coastal sandbars play a crucial role in shoreline protection, yet monitoring their dynamics remains challenging due to the cost and limited temporal coverage of traditional surveys. This study assesses the feasibility of using Sentinel-2 multispectral imagery combined with the logarithmic band ratio method to automatically detect submerged sandbar crests along three morphologically distinct beaches on the northwestern Mediterranean coast. Pseudo-bathymetry was derived from log-transformed band ratios of blue-green and blue-red reflectance used to extract the sandbar crest and validated against high-resolution in situ bathymetry. The blue-green band ratio achieved higher accuracy than the blue-red band ratio, which performed slightly better in very shallow waters. Its application across single, single/double, and double shore-parallel bar systems demonstrated the robustness and transferability of the approach. However, the method requires relatively clear or calm water conditions, and breaking-wave foam, sunglint, or cloud cover conditions limit the number of usable satellite images. A temporal analysis at a dissipative beach further revealed coherent bar migration patterns associated with storm events, consistent with observed hydrodynamic forcing. The proposed method is cost-free, computationally efficient, and broadly applicable for large-scale and long-term sandbar monitoring where optical water clarity permits. Its simplicity enables integration into coastal management frameworks, supporting sediment-budget assessment and resilience evaluation in data-limited regions. Full article

Coastal cities face escalating flood risk under sea-level rise, yet landscape-based adaptation strategies often remain speculative and weakly connected to the accessibility and economic constraints that shape sustainable urban development. This study developed a modeling-to-design framework that translates coupled climate and land-use projections into implementable landscape interventions, through planning-level spatial allocation, using Dalian, China as a case study under “middle of the road” (SSP2-4.5) climate conditions. The framework integrates the Land-use Evolution and Assessment Model (LEAM) with connected-bathtub flood modeling to evaluate whether strategic landscape design can redirect development away from flood-prone zones while accommodating projected growth and maintaining accessibility to employment and services. Interventions—protective wetland restoration (810 km²) and blue–green corridors (8 km²)—derived from a meta-synthesis of implemented coastal projects were operationalized as LEAM spatial constraints. Our results show that residential development can be redirected away from coastal risk with 100% demand satisfaction and elimination of moderate-risk allocations. Cropland demand was fully accommodated. In contrast, commercial development experienced 99.8% reduction under strict coastal protection, reflecting locational dependence on port-adjacent sites. This modeling-to-design framework offers a transferable approach to quantifying where landscape interventions succeed, where they face barriers, and where complementary measures are required, supporting decision-making that balances environmental protection, economic function, and social accessibility in sustainable coastal development. Full article

This study established a marine atmospheric corrosion prediction model by comparing the corrosion behavior of 7075 aluminum alloy in neutral salt spray tests and outdoor exposure tests conducted in the coastal atmosphere of Hainan. The results show that severe rusting occurred after 96 h of neutral salt spray testing, with loose white cluster-like corrosion products mainly composed of Al(OH)₃ and Al₂O₃. The thickening of the corrosion product layer slowed down the corrosion process, following a nonlinear power-law kinetic relationship. In the later stage, potential dropped sharply due to product layer spallation, and recovered as new corrosion products formed, confirming that the stability of the product layer is critical for protection. Under coastal atmospheric exposure, the composition of corrosion products was similar to that observed in the salt spray test, but the actual corrosion rate was affected by environmental dynamic equilibrium. The acceleration factor of the neutral salt spray test corresponding to the same corrosion amount in the Hainan marine atmosphere exhibited a declining trend, reflecting that differences in the protective nature of the corrosion product layer were influenced by environmental factors. Electrochemical analysis indicated that both tests showed similar current–potential synergistic variation mechanisms dominated by product layer stability. In summary, while the neutral salt spray test effectively simulates the chloride-induced corrosion mechanism in marine atmospheres, its kinetic model cannot directly predict real corrosion behavior through a simple acceleration factor, as environmental complexity must be considered. Full article

This paper presents a validated, data-driven framework for the sustainable rehabilitation of corrosion-damaged marine infrastructure, demonstrated through a comprehensive study on a historic coastal structure. The implemented three-phase methodology—integrating advanced condition assessment, evidence-based intervention design, and rigorous performance validation—successfully addressed severe chloride-induced deterioration. Diagnostic quantification revealed that 30% of the primary substructure was severely compromised, with chloride concentrations reaching 1.94% by weight (970% above the corrosion threshold) and half-cell potential mapping confirming a >90% probability of active corrosion in critical elements. Guided by this data, a synergistic intervention combining galvanic cathodic protection, high-performance coatings, and structural strengthening was deployed. Post-repair validation confirmed exceptional outcomes: a complete electrochemical repassivation (potential shift from −385 mV to −185 mV), a 97.3% reduction in chloride diffusion rates, a 250% increase in surface resistivity, and the restoration of structural capacity to 115% of design specifications. The framework achieved a 65% reduction in projected lifecycle costs while establishing a new paradigm for preserving marine infrastructure through evidence-based, multi-mechanism strategies that ensure long-term durability and economic viability. Full article

Accurate prediction of regional sea level anomaly (SLA) is critical for coastal hazard early warning, navigation safety, and infrastructure protection in economically active marginal seas such as the East China Sea (ECS), yet complex multiscale air–sea dynamics still make SLA forecasting challenging. This study proposes a Local Spatial Attention Transformer Network (LSATrans-Net) for short-term regional SLA prediction in the ECS, which incorporates a Local Spatial Attention mechanism designed for regional ocean processes and employs a first-order difference preprocessing strategy to reduce error accumulation induced by data non-stationarity. The LSATrans-Net outperforms ConvLSTM, BiLSTM, and CNN-Transformer in 7-day prediction experiments, with an RMSE of 0.017 m and a PCC of 0.984, with particularly strong forecasting skill in the ECS-Kuroshio and eddy-active regions. LSATrans-Net provides an efficient and physically interpretable framework for high-precision short-term SLA forecasting in dynamically complex marine regions, and offers reliable technical support for coastal disaster prevention and operational ocean forecasting systems. Full article

This study investigates the atmospheric corrosion behavior of zinc in tropical marine environments affected by hydrogen sulfide (H₂S), particularly from the decomposition of stranded Sargassum algae. Four exposure sites in Martinique with varying levels of H₂S and marine chlorides were selected. Gravimetric analysis showed that zinc thickness loss reached up to 45 µm after one year at the most impacted site (Frégate Est), compared to only 3–10 µm at less contaminated locations. This degradation level classifies the site as “extremely corrosive” according to ISO 9223. Electrochemical impedance spectroscopy (EIS) and linear polarization measurements revealed distinct corrosion behaviors. After 12 months of exposure, the polarization resistance and corrosion current density reached R_p = 916 Ω·cm² and I_corr = 28 µA·cm² at the Frégate Est site and R_p = 1835 Ω·cm² and I_corr = 6 µA·cm² at the Vauclin site. In H₂S-poor environments (Diamant, Vert-Pré, Vauclin), corrosion resistance increased over time due to the formation of protective layers such as hydrozincite and simonkolleite. In contrast, H₂S-rich environments favored the formation of sulfur-based compounds like elemental sulfur and zinc sulfide (ZnS), which exhibit poor protective properties and result in lower polarization resistance and higher corrosion current densities. Polarization curves confirmed a general decrease in anodic and cathodic currents over time, with less significant improvements in passivation at H₂S-impacted sites. The corrosion mechanism is influenced by both pollutant type and exposure duration. Overall, this study highlights the synergistic effect of H₂S and chlorides on accelerating zinc corrosion and underscores the need for adapted protection strategies in tropical coastal zones affected by Sargassum proliferation. Full article

Global demand for adaptable and rapidly deployable construction solutions in offshore, coastal, and fluvial environments continues to rise, driven by pressing needs to develop energy platforms, improve coastal resilience, and support emergency response in the face of natural disasters. Increased investment in human-made coastal infrastructure, such as piers, support structures for power lines, offshore wind farms, and seawall protection systems, further underscores this trend. This study investigates the development of printable concrete mixtures for underwater environments using seawater as a replacement for freshwater, using a 3D printing syringe-based extrusion system. The effect of seawater addition and the printing medium (in air vs. underwater) was assessed via rheological and mechanical performance characterization. The results indicate rheological properties are favorable for seawater adoption by producing mixtures with higher yield stress and viscosity with the same levels of admixtures used for freshwater. Seawater-based mixtures demonstrated superior dimensional stability compared to freshwater counterparts, maintaining cross-sectional geometry, while compressive strength results showed no statistical differences between in-air and underwater samples. However, flexural strength was significantly influenced by geometry and printing medium. These findings establish critical rheological parameters for printable underwater mixtures and highlight the need for optimized curing strategies and layer bonding techniques to improve interfacial strength in underwater 3D printing applications. Full article

Coastal wetlands, situated at the critical land–sea ecotone, play a vital role in sustaining ecological balance and supporting human activities. Currently, these ecosystems face dual stresses from climate change and intensified anthropogenic activities, making the quantitative assessment of ecosystem functions—represented by Gross Primary Productivity (GPP)—essential for their protection and management. However, a knowledge gap remains regarding coastal–urban complex ecosystems, and existing studies on coastal wetlands often overlook macro-environmental drivers beyond sea-level rise. This study leveraged the MOD17A2H V006 dataset to generate a 500 m GPP product for Zhanjiang City. We analyzed the spatiotemporal dynamics of GPP, utilized land use data to examine the evolution of coastal wetlands, and employed the Geodetector model to quantify the contributions of various factors to GPP in Zhanjiang and its coastal wetlands. The results indicate that: (1) GPP in Zhanjiang exhibited an overall steady upward trend, increasing at an average rate of $13.8\mathrm{g}\mathrm{C}·{\mathrm{m}}^{-2}·{\mathrm{yr}}^{-1}$. However, it displayed strong spatial heterogeneity, characterized by higher values in the southwest and lower values in the northern and coastal regions. (2) The land use pattern in Zhanjiang underwent significant transformations over the past two decades. Cropland and impervious surfaces expanded markedly, increasing by 194.6 km² and 290.42 km², respectively, while coastal wetland areas showed a continuous decline, with degraded and newly formed areas of 101.5 km² and 42 km², respectively. (3) The Geodetector results revealed that the q-value of Nighttime Light (NTL) increased from negligible values to over 0.1, emerging as a dominant driving factor. Although the driving force of anthropogenic activity factors on Zhanjiang and its coastal wetlands has steadily increased, natural factors currently remain the dominant forces. These findings unravel the driving mechanisms of natural and anthropogenic factors on GPP in Zhanjiang, providing valuable scientific evidence for the sustainable development of coastal ecosystems. Full article

This study reveals the distribution of floating macroalgae Sargassum in the East China Sea and Yellow Sea using HY-1C/D Coastal Zone Imager (CZI) data. A new inversion model, utilizing green and near-infrared bands, was developed for the 50 m resolution CZI data. This model effectively distinguishes Sargassum from Ulva prolifera and is effective in turbid coastal waters. Sargassum spatiotemporal distribution and drift patterns over five years were analyzed. Key findings demonstrate that (1) floating Sargassum exhibits distinct spatiotemporal distribution patterns. Sargassum initially emerges along Zhejiang’s eastern coast in February. During March and April, it concentrates east of Hangzhou Bay. While in May, Sargassum appears in the Yellow Sea, and is distributed near the Shandong Peninsula by June. Small patches of Sargassum are also found in the Yellow Sea from November to January. (2) Its distribution is influenced by various factors like nutrients, temperature, salinity, currents, and winds. Suitable nutrients, temperature, and salinity promote growth, while currents and winds, particularly in April–May, drive its northward drift from the East China Sea into the Yellow Sea. The Yellow Sea population originates from both drifting populations and local growth. (3) This research highlights the utility of HY-1C/D satellite data in coastal zone research, facilitating ecological monitoring and protection. Full article

Saline archaeological artifacts are highly susceptible to deterioration caused by salt crystallization and moisture–material interactions, particularly in coastal archaeological contexts affected by saline water intrusion. This persistent challenge necessitates the development of temporary, low-impact protective materials capable of limiting saline ingress. The present study reports on a preliminary assessment of modified polycaprolactone (PCL) films containing graphene oxide (GO) at 0.1%, 0.25%, and 0.5% to evaluate their potential as temporary barrier layers under saline stress conditions. Free-standing PCL/GO films were fabricated via solvent casting and exposed to natural Ionian seawater in a controlled laboratory incubation environment at 15 °C for up to 90 days, simulating early-stage saline exposure while controlling environmental variability and physical stress. Film behavior was evaluated through complementary surface, structural, mechanical, and permeability analyses. The findings indicate that GO content significantly influences surface wettability, microstructural evolution, and water transport properties. Low GO content (0.1%) enhanced barrier performance while maintaining structural integrity and controlled hydrolytic softening. In contrast, higher GO contents (0.25–0.5%) resulted in increased hydrophilicity, accelerated surface erosion, and greater mechanical degradation due to enhanced water uptake. Observed mass loss is attributed to early-stage hydrolysis rather than long-term biodegradation. This investigation is a material-level screening and does not represent a direct validation for conservation application. With superior stability and enhanced barrier properties, the optimized PCL/GO 0.1% film suggests significant potential for the protection of saline-affected archaeological materials. Full article

Under the dual pressures of rapid urbanization and climate change, urban expansion in high-density estuarine urban agglomerations has intensified economic–ecological trade-offs in the aquatic–terrestrial ecotone, necessitating land-use planning that reconciles economic growth with ecological protection. Here, we integrated linear programming with the CLUE-S model and incorporated marine–terrestrial integration objectives and typical natural disturbance factors. With this approach, a landscape pattern simulation framework capable of jointly optimizing ecological and economic benefits was developed. The framework was applied to the estuarine aquatic–terrestrial ecotone of the Pearl River Delta. This study drew on a land-use dataset, landscape dynamics, socioeconomic and biophysical drivers, and regional planning constraints to conduct simulation experiments under alternative development scenarios. The model achieved a Kappa coefficient of 0.904. From 2010 to 2020, built-up land expanded rapidly and encroached on ecological space. Simulations indicated that the natural evolution scenario increased fragmentation and ecological conflicts despite economic gains, whereas the sustainable development scenario balanced expansion and protection, reduced forestland fragmentation, safeguarded key ecological spaces, and improved ecological benefits while maintaining economic growth. Ecological benefits in the coastal aquatic–terrestrial ecotone from −0.2 to 0 km increased by 283.3%. The framework embeds land-use dynamics and spatial constraints, providing decision support for territorial spatial planning and ecological security pattern optimization. Full article

The Xiaohai Lagoon is a vital coastal ecosystem that has faced decades of significant natural and anthropogenic pressures. This study investigated the spatio-temporal dynamics its phytoplankton communities through quarterly sampling from 2024 to 2025. Significant spatial and seasonal variations (p < 0.05) in physicochemical parameters were observed. The concentrations of various physicochemical parameters were highest at the lagoon mouth and decreased inwards. In contrast, sites inside the lagoon experienced elevated nutrient and organic matter indicators. Seasonally, the highest temperatures were recorded in Summer. However, Autumn recorded the highest NH₃-N and NO₂-N levels, while Winter recorded the highest NO₃-N levels. The findings generally suggest minimal pollution, as key physicochemical parameters, met the China water quality standard for environmental protection (GB 3838–2002). Overall, 109 phytoplankton species belonging to 38 genera and 5 phyla, including Cyanophyta, Bacillariophyta, Chlorophyta, Cryptophyta, and Dinophyta, were identified. The phytoplankton average density was 1.65 × 10³ Ind L⁻¹ with insignificant differences both spatially and seasonally (p > 0.05). One-way ANOSIM indicated significant seasonal dissimilarity in phytoplankton community composition (R = 0.828, p < 0.001), with SIMPER results revealing that Ceratocorys sp., Chaetoceros sp., Coscinodiscus subtilis, Oscillatoria princes, and Thalassionema nitzschioides contributed to the seasonal difference. CCA indicated phytoplankton composition and abundance were influenced by COD, TN, TDS, salinity, oxidation-reduction potential, EC, water temperature, NH₃-N, and NO₃-N. This study highlights the critical need for effective management strategies to protect and preserve the ecological integrity of Xiaohai Lagoon. Full article

Stainless steels are commonly used in coastal structures and in seawater desalination and treatment systems, so understanding their corrosion behaviour under different salinity conditions is important to ensure the durability and reliability of the material. In this study, the behaviour of AISI 304L, AISI 316L, and 2205 duplex stainless steels (DSS) was tested in three media with different salinities: brackish water (BSW), seawater (SW), and concentrated seawater bittern (CSW). Testing was conducted using classical electrochemical methods (open circuit potential, linear, and potentiodynamic polarization) supplemented by surface analyses (optical microscopy, SEM/EDS, and optical profilometry). Corrosion resistance increased in the order AISI 304L < AISI 316L < 2205 DSS. Duplex steel 2205 performed best in all media: it exhibited the most positive open circuit potential, the highest polarization resistance, the lowest corrosion current density, and the widest passive range. Unexpectedly, CSW showed improved corrosion resistance compared to SW, which is explained by the reduced chloride content characteristic of seawater bittern after NaCl crystallisation and the presence of magnesium, calcium, and sulphate ions that promote the formation of protective deposits on the metal surface. Pronounced pitting was observed on AISI 304L steel in seawater, while surface degradation in brackish and concentrated seawater was significantly less, and 2205 DSS remained almost unchanged. The results obtained can serve as guidelines for the design and selection of materials for equipment and structures in industries operating in aggressive marine and coastal environments, such as desalination plants, shipbuilding, and energy systems. Full article

Climate change poses an unprecedented threat to global biodiversity, with birds serving as critical indicators of ecosystem responses. This study assessed the impacts of climate change on 29 endangered bird species in South Korea, a critical stopover region within the East Asian-Australasian Flyway (EAAF). Using Random Forest models, we predicted current (2010 baseline) and future species distributions under two climate scenarios (SSP2-4.5 and SSP5-8.5) for four time periods (2030s, 2050s, 2070s, and 2090s). Model performance was robust, with a mean AUC of 0.844 ± 0.122 across all species and 72.4% of species achieving AUC ≥ 0.80. Elevation emerged as the most influential predictor for 44.8% of species, followed by precipitation of the driest month (17.2%) and distance to water bodies (10.3%). Current species richness patterns showed spatial heterogeneity, with higher concentrations along coastal wetlands, particularly in the western and southern coasts and Jeju Island. Under SSP2-4.5, species richness patterns remained relatively stable through 2090, while SSP5-8.5 projected more dramatic shifts, particularly after 2070. Coastal regions and national parks exhibited differential responses, with some areas showing increases and others experiencing declines in species richness. High-elevation national parks, including Mt. Hallasan, Mt. Seoraksan, and Mt. Odaesan, demonstrated potential to serve as climate refugia, maintaining relatively stable species richness under both scenarios. Our spatial analysis at municipality and national park levels identified priority conservation areas and emphasized the need for climate refugium identification, habitat connectivity along elevational gradients, and adaptive management strategies. The findings provide actionable guidance for science-based conservation planning and contribute to international efforts to protect migratory birds along the EAAF. Urgent conservation measures are needed to safeguard coastal wetlands and establish ecological corridors to facilitate species range shifts under changing climatic conditions. Full article

The European Water Framework Directive (2000/60/EC) (WFD) aims to protect inland surface waters, transitional waters, coastal waters and groundwater. The overarching goal of the WFD is to reach a good aquatic ecosystem throughout all of Europe. With the aim of reaching this goal, article 4 of the WFD sets certain environmental objectives. According to article 4 of the WFD, all the surface water bodies falling under its scope should be of good chemical and ecological quality by the end of 2027, as most extension deadlines will expire. For artificial and heavily modified surface water bodies—which make up the vast majority in the Netherlands—the goal is not to achieve a good ecological status but instead a good ecological potential and a good chemical status. Point source discharges may have a major impact on water quality and in order to progress, a well-functioning permitting, supervision and enforcement (PSE) process is of considerable interest. So far little academic attention has been paid to the functioning and quality of the governance processes underlying the PSE process. This paper aims to reduce this knowledge gap by conducting a case study on Sitech, the wastewater company for the Chemelot industrial complex in Geleen in the province of Limburg, the Netherlands. We first elaborate on an assessment framework consisting of 18 good governance criteria. The framework is used to assess the permitting, supervision and enforcement process concerning the discharges of Chemelot industrial plant. Our assessment reveals that, despite significant improvements over the last decade, good governance in this case is only partially achieved. While in terms of accountability and resilience the process shows robust strengths, gaps are found in its inclusiveness, effectiveness and transparency. We conclude our paper with some reflections on the generalizability of our findings and some suggestions for further research and policymaking. Full article