Journal of Marine Science and Engineering

18 pages, 32233 KB

Open AccessArticle

Assessing Grain-Size and Sedimentological Variations in Human-Modified Beaches: Insights from the Northern Adriatic Coast (Italy)

by Ivan Martini, Leonardo Canapini, Lorenzo Terzi and Allegra Burgassi

J. Mar. Sci. Eng. 2025, 13(12), 2230; https://doi.org/10.3390/jmse13122230 (registering DOI) - 22 Nov 2025

Abstract

Human interventions have profoundly altered the depositional settings and morphodynamic evolution of beaches. Such environmental alterations also affect the execution of scientific studies because natural sedimentary and morphological signals are often masked by anthropogenic signatures. This paper focuses on two beaches in Northern [...] Read more.

Human interventions have profoundly altered the depositional settings and morphodynamic evolution of beaches. Such environmental alterations also affect the execution of scientific studies because natural sedimentary and morphological signals are often masked by anthropogenic signatures. This paper focuses on two beaches in Northern Italy that are heavily impacted by human activities. Through seasonal field observations and standardized sediment sampling combined with grain-size sediment analyses, this work aims to: (i) identify the sub-environments that are least affected by human disturbances and thus most suitable for geological monitoring and (ii) assess how different beach zones are influenced by seasonal variability and the presence of shore-parallel defense structures. The results indicate that the fair-weather berm is the most suitable area to record natural processes and seasonal changes, while step deposits reveal differences between protected and partially protected environments. These findings support standardized and reliable monitoring of human-modified beaches, providing practical guidance on where and how to conduct sediment sampling. Full article

(This article belongs to the Section Coastal Engineering)

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30 pages, 2805 KB

Open AccessArticle

Robust Offshore Wind Speed Forecasting via Quantum-Oppositional BKA-Optimized Adaptive Neuro-Fuzzy Inference System and Adaptive VMD Denoising

by Yingjie Liu and Fahui Miao

J. Mar. Sci. Eng. 2025, 13(12), 2229; https://doi.org/10.3390/jmse13122229 (registering DOI) - 22 Nov 2025

Abstract

Accurate offshore wind speed forecasting is crucial for ensuring stable energy production and safe offshore operations. However, the strong nonlinearity, non-stationarity, and chaotic behavior of offshore wind speed series make precise prediction extremely difficult. To overcome these difficulties, a two-stage synergistic prediction framework [...] Read more.

Accurate offshore wind speed forecasting is crucial for ensuring stable energy production and safe offshore operations. However, the strong nonlinearity, non-stationarity, and chaotic behavior of offshore wind speed series make precise prediction extremely difficult. To overcome these difficulties, a two-stage synergistic prediction framework is proposed. In the first stage, a multi-strategy Black-winged Kite Algorithm (MBKA) is designed, incorporating quantum population initialization, improved migration behavior, and oppositional–mutual learning to reinforce global optimization performance under complex coastal conditions. On this basis, an entropy-driven adaptive Variational Mode Decomposition (VMD) method is implemented, where MBKA optimizes decomposition parameters using envelope entropy as the objective function, thereby improving decomposition robustness and mitigating parameter sensitivity. In the second stage, the denoised intrinsic mode functions are used to train an adaptive Neuro-Fuzzy Inference System (ANFIS), whose membership function parameters are optimized by MBKA to enhance nonlinear modeling capability and prediction generalization. Finally, the proposed framework is evaluated using offshore wind speed data from two coastal regions in Shanghai and Fujian, China. Experimental comparisons with multiple state-of-the-art models demonstrate that the MBKA–VMD–ANFIS framework yields notable performance improvements, reducing RMSE by 57.14% and 30.68% for the Fujian and Shanghai datasets, respectively. These results confirm the effectiveness of the proposed method in delivering superior accuracy and robustness for offshore wind speed forecasting. Full article

(This article belongs to the Section Marine Energy)

22 pages, 5451 KB

Open AccessArticle

DiCAF: A Dual-Input Co-Attention Fusion Network with NMS Ensemble for Underwater Debris Detection

by Sungan Yoon and Jeongho Cho

J. Mar. Sci. Eng. 2025, 13(12), 2228; https://doi.org/10.3390/jmse13122228 (registering DOI) - 22 Nov 2025

Abstract

Underwater debris poses a significant threat to marine ecosystems, fisheries, and the tourism industry, necessitating the development of automated vision-based detection systems. Although recent studies have sought to enhance detection performance through underwater image enhancement, improvements in visual quality do not necessarily translate [...] Read more.

Underwater debris poses a significant threat to marine ecosystems, fisheries, and the tourism industry, necessitating the development of automated vision-based detection systems. Although recent studies have sought to enhance detection performance through underwater image enhancement, improvements in visual quality do not necessarily translate into higher detection accuracy and may, in some cases, degrade performance. To address this discrepancy between perceptual quality and detection reliability, we propose DiCAF, a dual-input co-attention fusion network built upon the latest You Only Look Once v11 detector. The proposed architecture processes both original and enhanced images in parallel and fuses their complementary features through a co-attention module, thereby improving detection stability and consistency. To mitigate high-frequency noise amplified during the enhancement process, a lightweight Gaussian filter is applied as a post-processing step, enhancing robustness against speckle noise commonly introduced by suspended particles in underwater environments. Furthermore, DiCAF incorporates a non-maximum suppression (NMS)-based ensemble that integrates detection outputs from three branches—original, enhanced, and fused—enabling complementary detection of objects missed by individual models and maximizing overall detection performance. Experimental results demonstrate that the proposed single-model DiCAF with Gaussian post-processing achieves an AP@0.5 of 0.87 and an AP@0.5:0.95 of 0.71 on a marine trash dataset. With the NMS-based ensemble, performance improves to 0.91 and 0.75, respectively. Under artificially injected speckle noise conditions, the proposed method maintains superior robustness, achieving an AP@0.5 of 0.62 and consistently outperforming conventional enhancement-based models. Full article

(This article belongs to the Section Ocean Engineering)

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30 pages, 5127 KB

Open AccessArticle

ROVON: An Ontology for Supporting Interoperability for Underwater Robots

by Mansour Taheri Andani and Farhad Ameri

J. Mar. Sci. Eng. 2025, 13(12), 2227; https://doi.org/10.3390/jmse13122227 - 21 Nov 2025

Abstract

Underwater robotics produces diverse and complex streams of sensor, image, video, and navigational data under challenging environmental conditions, creating obstacles for seamless integration and interpretation. This paper introduces ROVON (Remotely Operated Vehicle Ontology), a semantic framework designed to enhance interoperability and reasoning in [...] Read more.

Underwater robotics produces diverse and complex streams of sensor, image, video, and navigational data under challenging environmental conditions, creating obstacles for seamless integration and interpretation. This paper introduces ROVON (Remotely Operated Vehicle Ontology), a semantic framework designed to enhance interoperability and reasoning in underwater operations. While ROVON is conceptually scalable to large, heterogeneous datasets, its validation in this study focuses on controlled underwater inspection data collected for pipeline applications. ROVON enables the representation and analysis of multimodal underwater data by semantically annotating raw sensor feeds, enforcing data integrity, and leveraging knowledge graphs to convert disparate inputs into actionable insights. The ontology demonstrates how a structured semantic approach facilitates advanced analysis that improves decision-making, supports proactive maintenance strategies, and enhances operational safety. The proposed framework was validated through a controlled pipeline inspection scenario. Full article

(This article belongs to the Special Issue Innovations in Underwater Robotic Software Systems)

14 pages, 1472 KB

Open AccessArticle

Investigation of Turbulence Intensity Effects on Tidal Turbine Wakes Through the BEM–CFD Method

by Erhu Hou, Yang Li, Lining Zhu, Yanan Wu, Jie Ding and He Wu

J. Mar. Sci. Eng. 2025, 13(12), 2226; https://doi.org/10.3390/jmse13122226 - 21 Nov 2025

Abstract

The wake characteristics of tidal turbines are significantly influenced by turbulence intensity (TI) and flow velocity in the marine environment. This study employs the Blade Element Momentum (BEM)–CFD method to model two-bladed horizontal tidal turbine wakes, simplifying the turbine geometry while ensuring computational [...] Read more.

The wake characteristics of tidal turbines are significantly influenced by turbulence intensity (TI) and flow velocity in the marine environment. This study employs the Blade Element Momentum (BEM)–CFD method to model two-bladed horizontal tidal turbine wakes, simplifying the turbine geometry while ensuring computational efficiency. The numerical model, validated against experimental data, demonstrates reliable accuracy. Simulations were conducted for background TI levels of 2%, 6%, 10%, 14%, and 18%. Results indicate that wake regions initially expand and then contract, with the contraction point moving closer to the turbine as TI increases. At 2% TI, the wake influence region extends to an axial distance/diameter (X/D) ratio of 20, while at 18% TI, contraction begins at X/D = 4. Low TI results in more extensive low-speed regions, whereas high TI accelerates wake recovery. As TI increases, the wake’s turbulence rapidly blends with the background, leading to a reduction in turbulence increments within the wake. Additionally, an analytical wake model for tidal turbines was developed, incorporating turbulence intensity into the formula. The predicted curve exhibited good agreement with the CFD data. This model enables a quick and efficient prediction of wake velocity changes under varying turbulence intensities. Full article

(This article belongs to the Special Issue Advances in Marine Engineering Hydrodynamics, 2nd Edition)

28 pages, 1238 KB

Open AccessArticle

Analyzing the Impact of Climate Resilience on Container Terminal Throughput: A Continent-Wide Comparative Study

by Jeongmin Lee, Wonhyeong Ryu, Yul-seong Kim and Chang-hee Lee

J. Mar. Sci. Eng. 2025, 13(12), 2225; https://doi.org/10.3390/jmse13122225 - 21 Nov 2025

Abstract

As the response to climate change transitions from passive adaptation to transformation and resilience, the importance of climate resilience has become increasingly evident. The port logistics industry is highly vulnerable to climate change, and the efficacy of climate resilience within the sector must [...] Read more.

As the response to climate change transitions from passive adaptation to transformation and resilience, the importance of climate resilience has become increasingly evident. The port logistics industry is highly vulnerable to climate change, and the efficacy of climate resilience within the sector must be empirically validated. In this study, we aim to investigate the impact of national climate resilience on container port throughput. To achieve this, we conducted a panel regression analysis using data spanning 13 years (2010–2022) from 83 countries. The findings reveal that, overall, climate resilience positively influences container port throughput, but in Latin America, it showed a negative correlation. This suggests that the relationship between climate resilience and container port throughput varies depending on regional characteristics and factors. Further, climate resilience indicators specific to the port logistics industry should be developed. This study serves as a foundational exploration into climate resilience in the port logistics industry, providing empirical evidence of its critical role. The findings serve as a foundation for sustainable development and policy decision-making. Full article

(This article belongs to the Section Ocean Engineering)

35 pages, 10678 KB

Open AccessReview

Advances in Smart Coating Technologies for Wind Turbine Blade Protection: A Focus on Self-Healing and Anti-Erosion Performance

by Mohamad Alsaadi, Leon Mishnaevsky, Jr., Edmond Francis Tobin and Declan M. Devine

J. Mar. Sci. Eng. 2025, 13(12), 2224; https://doi.org/10.3390/jmse13122224 - 21 Nov 2025

Abstract

Leading-edge erosion (LEE) of wind-turbine blades, driven primarily by rain erosion, particulate erosion, and environmental ageing, remains one of the most pervasive causes of performance loss and maintenance cost in offshore and onshore wind farms. Self-healing coatings, which autonomously or semi-autonomously restore barriers [...] Read more.

Leading-edge erosion (LEE) of wind-turbine blades, driven primarily by rain erosion, particulate erosion, and environmental ageing, remains one of the most pervasive causes of performance loss and maintenance cost in offshore and onshore wind farms. Self-healing coatings, which autonomously or semi-autonomously restore barriers and mechanical function after damage, promise a paradigm shift in blade protection by combining immediate impact resistance with in-service reparability. This review surveys the state of the art in self-healing coating technologies (intrinsic chemistries such as non-covalent interactions or dynamic covalent bonds; extrinsic systems including micro/nanocapsules and microvascular networks) and evaluates their suitability for anti-erosion, mechanical robustness, and multifunctional protection of leading edges. The outcomes of theoretical, experimental, modelling and field-oriented studies on the leading-edge protection and coating characterisation identify which self-healing concepts best meet the simultaneous requirements of toughness, adhesion, surface finish, and long-term durability of wind blade applications. Key gaps are highlighted, notably trade-offs between healing efficiency and mechanical toughness, challenges in large-area and sprayable application methods, and the need for standardised characterisation and testing of self-healing coating protocols. We propose a roadmap for targeted materials research, accelerated testing, and field trials. This review discusses recent studies to guide materials scientists and renewable-energy engineers toward promising routes to deployable, multifunctional, self-healing anti-erosion coatings, especially for wind-energy infrastructure. Full article

(This article belongs to the Special Issue Sustainable Marine and Offshore Systems for a Net-Zero Future)

25 pages, 13109 KB

Open AccessArticle

Interpretation Analysis of Influential Variables Dominating Impulse Waves Generated by Landslides

by Xiaohan Xu, Peng Qin, Zhenyu Li, Jiangfei Wang, Yuyue Zhou, Sen Zheng and Zhenzhu Meng

J. Mar. Sci. Eng. 2025, 13(12), 2223; https://doi.org/10.3390/jmse13122223 - 21 Nov 2025

Abstract

Landslide impacts into water generate impulse waves that, in confined basins and along steep coasts, escalate swiftly into hazardous near-shore surges. In this study, we present a scenario-aware workflow using gradient boosting and k-means clustering, and explain them using Shapley additive explanations [...] Read more.

Landslide impacts into water generate impulse waves that, in confined basins and along steep coasts, escalate swiftly into hazardous near-shore surges. In this study, we present a scenario-aware workflow using gradient boosting and k-means clustering, and explain them using Shapley additive explanations (SHAPs). Two cases are addressed: forecasting at water entry (Scenario I) with predictors Froude number

F r

, relative effective mass M, and relative thickness S; and pre-event assessment (Scenario II) with predictors Bingham number

B i

, relative moving length L, and relative initial mass

M i

. Using 270 controlled physical-model experiments, we benchmark six learning algorithms under 5-fold cross-validation. Gradient boosting delivers the best overall accuracy and cross-scenario robustness, with XGBoost close behind. Scenario I attains a coefficient of determination

R^{2}

of 0.941, while Scenario II achieves

R^{2} = 0.865

. Residual analyses indicate narrower spreads and lighter tails for the top models. SHAP reveals physics-consistent controls: M and

F r

dominate Scenario I, whereas initial mass and the

B i

dominate Scenario II; interactions

F r \times S

and

M i \times B i

clarify non-linear amplification of wave amplitude and height. The cluster–predict–explain framework couples predictive skill with physical transparency and is directly applicable to coastal hazard screening and integration into shoreline early-warning workflows. Full article

(This article belongs to the Special Issue Coastal Disaster Assessment and Response—2nd Edition)

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16 pages, 2825 KB

Open AccessArticle

Tidal Zonation Shapes Microbial Communities and Sediment Properties in a UNESCO World Heritage Site (Gomso Bay, Korea)

by Maheshkumar Prakash Patil, Sang Ock Ryu, Hee-Eun Woo, Chang-Gun Lee, Ha Neul Oh, So Yun Jang, Jong-Oh Kim and Kyunghoi Kim

J. Mar. Sci. Eng. 2025, 13(12), 2222; https://doi.org/10.3390/jmse13122222 - 21 Nov 2025

Abstract

This study investigates the effect of intertidal zonation on sediment characteristics, organic matter content, and microbial community distribution in Gomso Bay, Republic of Korea—an ecologically significant estuarine system and part of the UNESCO-designated Getbol, Korean Tidal Flats. It was hypothesized that physicochemical properties [...] Read more.

This study investigates the effect of intertidal zonation on sediment characteristics, organic matter content, and microbial community distribution in Gomso Bay, Republic of Korea—an ecologically significant estuarine system and part of the UNESCO-designated Getbol, Korean Tidal Flats. It was hypothesized that physicochemical properties and microbial communities differ significantly among the inner, middle, and outer tidal zones due to variations in tidal exposure, sediment texture, and organic matter accumulation. Sediment samples were collected from nine sites across these zones and analyzed for total organic carbon (TOC), acid volatile sulfide (AVS), and trace metals (As, Cd, Cr, Cu, Hg, Li, Ni, Pb, Zn), along with sediment texture. Microbial community structure was examined using 16S rRNA gene amplicon sequencing to evaluate the influence of zonation on microbial diversity and composition. Results revealed distinct spatial variations along the intertidal gradient. Inner tidal zones with finer sediments showed higher TOC, AVS, and metal concentrations, whereas outer zones with coarser sediments exhibited lower values. Microbial composition also varied, with aerobic microorganisms dominating the high tidal flats and anaerobic taxa prevailing in the low tidal flats. Heterotrophic and autotrophic bacteria were more abundant in the outer zone, while chemolithotrophs predominated in the inner zone. Redundancy and Pearson’s correlation analyses further indicated significant relationships between sediment texture, TOC, AVS, heavy metals, and microbial diversity. Overall, the findings confirm that tidal zonation drives distinct sedimentary and microbial patterns, highlighting the ecological complexity of intertidal ecosystems. Full article

(This article belongs to the Special Issue Selected Feature Papers in Marine Environmental Science)

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24 pages, 4769 KB

Open AccessArticle

Trajectory Planning Method for Multi-UUV Formation Rendezvous in Obstacle and Current Environments

by Tao Chen, Kai Wang and Qingzhe Wang

J. Mar. Sci. Eng. 2025, 13(12), 2221; https://doi.org/10.3390/jmse13122221 - 21 Nov 2025

Abstract

Formation rendezvous is a critical phase during the deployment or recovery of multiple unmanned underwater vehicles (UUVs) in cooperative missions, and represents one of the core problems in multi-UUV cooperative planning. In practical marine environments with obstacles and currents, multiple constraints must be [...] Read more.

Formation rendezvous is a critical phase during the deployment or recovery of multiple unmanned underwater vehicles (UUVs) in cooperative missions, and represents one of the core problems in multi-UUV cooperative planning. In practical marine environments with obstacles and currents, multiple constraints must be simultaneously satisfied, including obstacle avoidance, inter-UUV collision prevention, kinematic limitations, and specified initial and terminal states. These requirements make energy-optimal trajectory planning for multi-UUV formation rendezvous highly challenging. Traditional integrated cooperative planning methods often struggle to obtain optimal or even feasible solutions due to the complexity of constraints and the vastness of the solution space. To address these issues, a dual-layer planning framework for multi-UUV formation rendezvous trajectory planning in environments with obstacles and currents is proposed in this paper. The framework consists of an initial individual trajectory planning layer and a secondary cooperative planning layer. In the initial individual trajectory planning stage, the Grey Wolf Optimization (GWO) algorithm is employed to optimize high-order terms of polynomial curves, generating initial trajectories for individual UUVs that satisfy obstacle avoidance, kinematic constraints, and state requirements. These trajectories are then used as inputs to the secondary cooperative planning stage. In the cooperative stage, a Self-Adaptive Particle Swarm Optimization (SAPSO) is introduced to explicitly address inter-UUV collision avoidance while incorporating all individual constraints, ultimately producing a cooperative rendezvous trajectory that minimizes overall energy consumption. To validate the effectiveness of the proposed method, a simulation environment incorporating vortex flow fields and real-world island topography was constructed. Simulation results demonstrate that the proposed hierarchical trajectory planning method is capable of generating energy-optimal formation rendezvous trajectories that satisfy multiple constraints for multi-UUV systems in environments with obstacles and ocean currents, highlighting its strong potential for practical engineering applications. Full article

(This article belongs to the Section Ocean Engineering)

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27 pages, 524 KB

Open AccessArticle

Assessment of Differences Between the Ports of Rotterdam, Valparaíso and San Antonio Towards Smart Ports, Emphasising Digital Technologies

by Luis Valenzuela-Silva, Miguel Muñoz, Carolina Lagos, J. P. Sepúlveda-Rojas and Raúl Carrasco

J. Mar. Sci. Eng. 2025, 13(12), 2220; https://doi.org/10.3390/jmse13122220 - 21 Nov 2025

Abstract

The objective is to evaluate the differences between the Chilean ports of Valparaíso and San Antonio and the port of Rotterdam in their journey towards smart ports, focusing on Blockchain (BC) technologies, Artificial Intelligence (AI), big data, Internet of Things (IoT), 5G networks [...] Read more.

The objective is to evaluate the differences between the Chilean ports of Valparaíso and San Antonio and the port of Rotterdam in their journey towards smart ports, focusing on Blockchain (BC) technologies, Artificial Intelligence (AI), big data, Internet of Things (IoT), 5G networks and Digital Twins (DT), according to Port 4.0 and 5.0 models. The methodology is a qualitative assessment based on scores from the analysis of Port 4.0 technology information, including labour relations, environmental care and community integration for Port 5.0. The results confirm Rotterdam as representative of a ‘Smart Port’ for Ports 4.0 and 5.0, showing gaps with Chilean ports, which are rated as ‘incipient implementation’ in Port 4.0 and ‘in transition’ in Port 5.0. These differences are due to factors such as investment, financing, infrastructure, governance, regulation, digital human capital, organisational culture and innovation, and the characteristics of the port ecosystem. Full article

(This article belongs to the Special Issue Smart Seaport and Maritime Transport Management, Second Edition)

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24 pages, 3332 KB

Open AccessArticle

Comparative Study on Alternative Umbilical Cable Configurations for Deep-Sea Mining System

by Wen Shen, Zhenqin Yuan, Shuqing Wang, Lei Li, Xinrui Yang, Jiancheng Liu, Chaojun Huang, Shipeng Wang and Fengluo Chen

J. Mar. Sci. Eng. 2025, 13(12), 2219; https://doi.org/10.3390/jmse13122219 - 21 Nov 2025

Abstract

The umbilical cable plays a critical role in deep-sea mining systems by connecting the surface support vessel to the mining vehicle. If the spatial configuration of the umbilical cable is unsuitable for mining vehicle operations, it may experience overloading, slack, seabed contact, or [...] Read more.

The umbilical cable plays a critical role in deep-sea mining systems by connecting the surface support vessel to the mining vehicle. If the spatial configuration of the umbilical cable is unsuitable for mining vehicle operations, it may experience overloading, slack, seabed contact, or be run over by the mining vehicle. To address these issues, this study focuses on double-stepped, steep-wave, and S-shaped configurations and develops a coupled dynamic model of the surface support vessel–umbilical–mining vehicle system using the lumped-mass method, which incorporates hydrodynamic loads induced by currents and irregular waves, as well as motion excitations from the surface support vessel. The spatial configurations and mechanical responses of three umbilical configurations were evaluated, including maximum effective tension, lateral drift amplitude, and the mining vehicle’s overturning moment. The results indicate that the double-stepped configuration offers superior performance in terms of ground clearance, effective tension, and collaborative operation of the mining vehicle, although it faces an increased risk of fatigue failure due to dual buoyancy sections. The S-shaped configuration exhibits improved control of lateral drift and bending response under ocean current excitation, while the steep-wave configuration demonstrates intermediate behavior. In addition, the study analyzed the local compression of the umbilical cable and the variation trends of the mining vehicle’s overturning moments. These findings offer insights into the optimization of umbilical design and operational parameters, enhancing the safety, reliability, and efficiency of deep-sea mining systems. Full article

(This article belongs to the Section Ocean Engineering)

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18 pages, 6422 KB

Open AccessArticle

Mechanism of Permeability Evolution in Coral Reef Limestone Under Variable Confined Pressure Using Nuclear Magnetic Resonance Technology

by Yang Mo, Haifeng Liu, Yongtao Zhang, Shun Zhai, Peishuai Chen, Ru Qu and Fuquan Ji

J. Mar. Sci. Eng. 2025, 13(12), 2218; https://doi.org/10.3390/jmse13122218 - 21 Nov 2025

Abstract

The development of underground space in the South China Sea islands is an important way to enhance their protection capabilities. This study focuses on the stress loading and unloading conditions of surrounding rock during the excavation of underground caverns in island reefs. Laboratory [...] Read more.

The development of underground space in the South China Sea islands is an important way to enhance their protection capabilities. This study focuses on the stress loading and unloading conditions of surrounding rock during the excavation of underground caverns in island reefs. Laboratory variable confining pressure permeability tests were conducted to quantify the stress sensitivity of permeability in coral reef limestone based on Darcy’s law and the stress sensitivity index model equation for permeability. In addition, the use of nuclear magnetic resonance technology reveals the microscopic mechanism of coral reef limestone permeability evolution. The results of the experiments show that the permeability of coral reef limestone sample is mainly controlled by the advantaged permeable channels formed by large pores. During the stress loading stage, the pore structure inside the sample changes, with compression of large pores and generation of smaller pores, resulting in a decrease in effective permeable pathways and a decrease in permeability. When the stress loading reaches 4 MPa, the damage rate of the sample’s permeability is 19.6%. During the stress unloading stage, the recovery of the sample’s permeability shows a significant hysteresis effect. Due to the irreversible damage caused by the compression and collapse of the pore structure during the loading stage, the permeability of the sample cannot fully recover when unloaded to the initial stress state. Based on the experimental results, calculations show that the stress sensitivity coefficient of coral reef limestone permeability is 1.1 × 10⁻¹ MPa⁻¹, which is higher than that of conventional land-based rocks. The conclusions of this study can provide important design references for the stability control of surrounding rocks and geological hazard prevention during the excavation of underground chambers on the islands. Full article

(This article belongs to the Special Issue Submarine Unfavorable Geology and Geological Disasters)

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21 pages, 6349 KB

Open AccessArticle

PLPGR-Net: Photon-Level Physically Guided Restoration Network for Underwater Laser Range-Gated Image

by Qing Tian, Longfei Hu, Zheng Zhang and Qiang Yang

J. Mar. Sci. Eng. 2025, 13(12), 2217; https://doi.org/10.3390/jmse13122217 - 21 Nov 2025

Abstract

Underwater laser range-gated imaging (ULRGI) effectively suppresses backscatter from water bodies through a time-gated photon capture mechanism, significantly extending underwater detection ranges compared to conventional imaging techniques. However, as imaging distance increases, rapid laser power attenuation causes localized pixel loss in captured images. [...] Read more.

Underwater laser range-gated imaging (ULRGI) effectively suppresses backscatter from water bodies through a time-gated photon capture mechanism, significantly extending underwater detection ranges compared to conventional imaging techniques. However, as imaging distance increases, rapid laser power attenuation causes localized pixel loss in captured images. To address ULRGI’s limitations in multi-frame stacking—particularly poor real-time performance and artifact generation—this paper proposes the Photon-Level Physically Guided Underwater Laser-Gated Image Restoration Network (PLPGR-Net). To overcome image degradation caused by water scattering and address the challenge of strong coupling between target echo signals and scattering noise, we designed a three-branch architecture driven by photon-level physical priors. This architecture comprises: scattering background suppression module, sparse photon perception module, and enhanced U-Net high-frequency information recovery module. By establishing a multidimensional physical constraint loss system, we guide image reconstruction across three dimensions—pixels, features, and physical laws—ensuring the restored results align with underwater photon distribution characteristics. This approach significantly enhances operational efficiency in critical applications such as underwater infrastructure inspection and cultural relic detection. Comparative experiments using proprietary datasets and state-of-the-art denoising and underwater image restoration algorithms validate the method’s outstanding performance in deeply integrating physical interpretability with deep learning generalization capabilities. Full article

(This article belongs to the Special Issue Advancements in Deep-Sea Equipment and Technology, 3rd Edition)

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19 pages, 172530 KB

Open AccessArticle

Cenozoic Stratigraphic Architecture of the Beikang Basin (South China Sea): Insights into Tectonic Evolution and Sedimentary Response

by Shuaibing Luo, Xiaoxue Wang, Lifu Zhang, Li Zhang, Kangshou Zhang, Guanghui He and Qiuhua Yu

J. Mar. Sci. Eng. 2025, 13(12), 2216; https://doi.org/10.3390/jmse13122216 - 21 Nov 2025

Abstract

Since the onset of the Cenozoic, the South China Sea has experienced complex plate interactions including peripheral plate collisions, the demise of the Paleo-South China Sea, and the subsequent opening of the modern basin. These processes produced three major types of sedimentary basins: [...] Read more.

Since the onset of the Cenozoic, the South China Sea has experienced complex plate interactions including peripheral plate collisions, the demise of the Paleo-South China Sea, and the subsequent opening of the modern basin. These processes produced three major types of sedimentary basins: extensional, strike-slip, and compressional. The Beikang Basin represents a typical extensional continental-margin rift basin that preserves the stratigraphic and sedimentary record of the transition from syn-rift to post-rift stages. Subsidence happened mainly during the post-rift stage. Five structural styles exist: extensional, compressional-inversion, strike-slip–extensional, magmatic, and diapiric. While the first three are fault-related, the last two are mainly controlled by the volcanic phases. Using a seismic-facies-to-sedimentary-system workflow, we delineate a tectono-stratigraphic framework, comprising five seismic facies, seven lithofacies, and eight depositional facies. This framework indicates that the Beikang Basin evolved through four major tectonic stages including initial rifting, inherited rifting, climax rifting, and post-rift thermal subsidence. Each stage has primary control on sediment supply and accommodation development. Our findings refine the basin’s tectono-sedimentary evolution and improve predictions for sediment distribution and hydrocarbon exploration in the underexplored Beikang Basin. Full article

(This article belongs to the Special Issue Advances in Sedimentology and Coastal and Marine Geology, 3rd Edition)

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19 pages, 4826 KB

Open AccessArticle

Hydrodynamic Effects and Scour Protection of a Geotextile Mattress with a Floating Plate

by Yehui Zhu, Yanhong Li and Liquan Xie

J. Mar. Sci. Eng. 2025, 13(12), 2215; https://doi.org/10.3390/jmse13122215 - 21 Nov 2025

Abstract

In this study, the evolution of the flow field near a Geotextile Mattress with a Floating Plate (GMFP) are numerically investigated, with a specific focus on the influence of the Froude number and the dynamic response of the floating plate. Key findings identify [...] Read more.

In this study, the evolution of the flow field near a Geotextile Mattress with a Floating Plate (GMFP) are numerically investigated, with a specific focus on the influence of the Froude number and the dynamic response of the floating plate. Key findings identify a critical Froude number that separates two protection regimes. Below this critical flow condition, the bottom vortex and the protective zone remain stable. Above it, the vortex contracts upstream, and the protection efficacy becomes substantial but diminished due to the competing effects of vortex development and a reduction in plate obstruction height. The bed shear stress over a considerable distance leeward of the GMFP is significantly reduced compared to unprotected conditions. Due to the blockage of the GMFP, upstream backup and downstream drawdown were observed in the water surface over the GMFP. These results provide valuable insights for the design and application of GMFPs, particularly in optimizing structural parameters to enhance protection effectiveness under varying flow conditions. Full article

(This article belongs to the Special Issue Advanced Studies in Marine Structures)

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18 pages, 1788 KB

Open AccessArticle

Robust Relative Space Motion Control of Underwater Vehicles Using Time Delay Estimation

by Gun Rae Cho, Hyungjoo Kang, Min-Gyu Kim, Sungho Park, Chulhee Bae, Han-Sol Jin, Seongho Jin and Ji-Hong Li

J. Mar. Sci. Eng. 2025, 13(11), 2214; https://doi.org/10.3390/jmse13112214 - 20 Nov 2025

Abstract

This paper presents a robust trajectory-tracking control framework for underwater vehicles operating in a relative coordinate system. Unlike conventional methods that define trajectories in the world frame, the proposed approach formulates the control problem directly in a moving reference frame, enabling accurate motion [...] Read more.

This paper presents a robust trajectory-tracking control framework for underwater vehicles operating in a relative coordinate system. Unlike conventional methods that define trajectories in the world frame, the proposed approach formulates the control problem directly in a moving reference frame, enabling accurate motion control with respect to dynamic and drifting objects affected by environmental disturbances such as ocean currents and waves. This relative-space formulation is particularly advantageous for tasks including diver guidance, floating-object inspection, and docking, where the reference itself is nonstationary. A coordinate transformation is introduced to consistently express the vehicle dynamics in the relative frame. Based on the transformed dynamics, a Time Delay Control (TDC) law is applied to estimate unmodeled dynamics and external disturbances without requiring precise system parameters. Theoretical stability analysis shows that the stability condition of the proposed controller is consistent with that of conventional TDC, allowing similar gain-tuning procedures. Simulation results demonstrate that the proposed controller achieves robust and smooth trajectory tracking even when the reference frame undergoes motion induced by ocean currents. Full article

(This article belongs to the Special Issue Advanced Control Strategies for Autonomous Maritime Systems)

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57 pages, 15734 KB

Open AccessArticle

Study on Combustion Characteristics of Compression Ignition Marine Methanol/Diesel Dual-Fuel Engine

by Zhongcheng Wang, Jie Zhu, Xiaoyu Liu, Jingjun Zhong and Xin Jiang

J. Mar. Sci. Eng. 2025, 13(11), 2213; https://doi.org/10.3390/jmse13112213 - 20 Nov 2025

Abstract

With the increasing global demand for environmental protection and sustainable energy utilization, methanol, as a clean and renewable fuel, has become a research focus in the field of marine engines. However, its application in compression ignition engines faces bottlenecks such as low combustion [...] Read more.

With the increasing global demand for environmental protection and sustainable energy utilization, methanol, as a clean and renewable fuel, has become a research focus in the field of marine engines. However, its application in compression ignition engines faces bottlenecks such as low combustion efficiency and poor stability. Taking the L23/30H marine diesel engine as the research object, this paper establishes a combustion simulation model for a methanol/diesel dual-fuel direct-injection engine. The reliability of the model is ensured through grid independence verification and model calibration, and a coupled chemical reaction kinetic mechanism containing 126 species and 711 elementary reactions is constructed. A systematic study is conducted on the effects of injection strategies, including fuel operating modes, spray development patterns, injection intervals, and injection timing, on combustion characteristics. The results show that under the optimized injection strategy (vertical cross spray + synchronous injection) proposed in this study and operating conditions with a high methanol substitution ratio, the combustion efficiency, dynamic performance, and soot emission control effect of the dual-fuel mode are superior to those of the pure diesel mode. Simulation results show that the combined strategy of vertical cross injection and synchronous injection can significantly increase the indicated thermal efficiency (ITE) by 3.2%, reduce the brake specific fuel consumption (BSFC) by approximately 4.5%, advance the peak heat release by 2 °CA, and remarkably improve the combustion efficiency, while earlier injection timing is beneficial to air–fuel mixing. Further comparison of combustion and emission characteristics under different boundary conditions such as methanol energy ratios and injection pressures reveals that increasing methanol injection pressure, compression ratio, and initial pressure can improve combustion uniformity and reduce soot emissions, but NO_x emissions increase, which requires the coordination of after-treatment technologies. Through the comprehensive optimization of multiple parameters, efficient and clean combustion under a high methanol substitution rate is achieved. This paper provides theoretical support and practical guidance for the technological development of marine methanol dual-fuel engines. In the future, industrial applications can be promoted by combining actual engine tests and after-treatment technologies. Full article

(This article belongs to the Special Issue Advanced Technologies for New (Clean) Energy Ships—2nd Edition)

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22 pages, 1579 KB

Open AccessArticle

Integrated Sediment and Mussel Chemical Analysis for Environmental Quality Assessment in Rovinj’s Coastal Waters (Northern Adriatic, Croatia)

by Jadranka Pelikan, Kristina Grozić, Luca Privileggio, Dijana Pavičić-Hamer, Mirta Smodlaka Tanković, Kristina Pikelj, Marin Glad and Bojan Hamer

J. Mar. Sci. Eng. 2025, 13(11), 2212; https://doi.org/10.3390/jmse13112212 - 20 Nov 2025

Abstract

Marine sediments are a key component of aquatic ecosystems, linking diverse water uses, functions, and services. Chemical contamination of sediments is a global concern, with many jurisdictions striving to prevent future pollution and manage existing contamination. This study evaluates the contamination status of [...] Read more.

Marine sediments are a key component of aquatic ecosystems, linking diverse water uses, functions, and services. Chemical contamination of sediments is a global concern, with many jurisdictions striving to prevent future pollution and manage existing contamination. This study evaluates the contamination status of Rovinj’s coastal waters using an integrated approach that combines sediment and biota chemical analyses. Sediments were analyzed to assess long-term contaminant accumulation (D8.C1), while the Mediterranean mussel (Mytilus galloprovincialis) served as a bioindicator of bioavailable contaminants and their cumulative effects on marine habitats (D8.C2). Sediment samples were collected from five sites (S1–S5), and mussels were caged using Mussel Watch installations for approximately 120 days at a control site (Lim Bay) and within Rovinj harbor. Both matrices were analyzed for heavy metals (As, Cd, Cu, Cr, Hg, Ni, Pb, and Zn), polycyclic aromatic hydrocarbons (16 PAHs), and polychlorinated biphenyls (PCBs), following the EU Water Framework Directive. All sampled locations showed a reduction in sediment contamination relative to 2011 data, with most concentrations below ecotoxicological thresholds. Exceptions included elevated ΣPAH and PCB concentrations in the harbor (S1 = 3.18 mg/kg DW; 0.33 mg/kg DW) and marina (S2 = 3.64 mg/kg DW; 0.89 mg/kg DW), as well as Ni levels (S3 = 30 mg/kg DW; S4 = 34 mg/kg DW). Despite higher contaminant loads at some locations, mussel contaminant bioaccumulation remained limited, and their vitality and survival were only moderately affected in the harbor. Although localized increases in some contaminants were detected, all calculated Q_PECm values remained below 1.0, indicating no significant ecological risk. However, a moderate-to-high probability of toxic effects (P) may occur with long-term exposure for biota inhabiting harbor and marina areas. The results of this study demonstrate continued improvement in the environmental quality of Rovinj’s coastal waters compared to the previous decade. Full article

(This article belongs to the Special Issue Assessment and Monitoring of Coastal Water Quality)

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