Journal of Marine Science and Technology-Taiwan

Current Articles

    • Research Article15 September 2026

      Reliable Performance Analysis of Polyurea Coatings Used in Offshore Wind Turbines

      This study explores the weather resistance, mechanical properties and corrosion resistance of polyurea coatings in marine environments. The relevant analysis results can be used as a reliability assessment of offshore wind turbine structural coatings during their service life under the influence of marine environments. The long-term experiment uses seawater and 70°C thermal aging conditions as coating reliability assessment items. The microstructure of the samples that have been immersed in seawater for a long time and thermally aged is observed using a scanning electron microscope (SEM). The results show that the surface of the 100 and 125 series polyurea coatings is flat at the beginning of the seawater corrosion test (96 hours). At this time point, the polyurea coating will be accompanied by the phenomenon of mechanical property recovery (i.e., the mechanical properties are improved). When the test time is increased to 168 hours to 3 months, precipitates will appear on the coating surface and holes will form; when the test time is increased to 5-12 months, wrinkles and holes will appear on the test piece. After the functional group detection by Fourier transform infrared spectroscopy (FTIR), the spectrum shows that the peak at a frequency of 3300 cm⁻¹ belongs to the stretching vibration reaction of the N-H bond, and the peak intensity of the N-H bond will weaken as the test time increases. The peak at a frequency of 1660–1620 cm⁻¹ belongs to the carbonyl bond. The test results show that the carbonyl bond peak will shift as the test time increases. This shift belongs to the reaction of hydrogen bond aging and dissociation. Finally, the mechanical property test results show that the mechanical property retention rate of the coating can be maintained at more than 80% after long-term testing. The results of the QUV test and the marine exposure test show that the corrosion rate of the steel pile coating in the marine environment is only 0.00141 mm/year, the weight loss is 0.076%, and there is no significant peeling on the coating surface, only seaweed and shells are attached. The actual results of marine corrosion show that the polyurea coating has excellent corrosion resistance and has long-term stability in harsh marine environments, and can be used as an outer protective layer for marine structures.
    • Research Article15 September 2026

      Corrosion Testing and Simulation of Taiwan Offshore Wind Foundations

      Taiwan is located in the subtropical zone, with high relative humidity and high salinity in the air, and there are marine organisms attached to structures in the sea. This study will analyze the durability of the corrosion structure materials of the underwater foundation of offshore wind turbines based on the local chemical environment and paint materials. The offshore wind turbine underwater infrastructure is placed in the small boat dock area of the National Taiwan Ocean University in Taiwan. Nine kinds of coatings certified by NORSOK M501 were used to prepare specimens, and the metal exposure test was carried out by hanging in seawater. The hanging positions were respectively in the atmospheric zone, splash zone and submerged zone to complete the analysis of the effect of the water environment and attached marine organisms on the corrosion of the coatings.  The results show that the growth stage of the oyster shells attached to the steel pile will be more mature. The BEASY simulation software was used to analyze the corrosion voltage, and the results of the simulated cathodic corrosion protection of steel piles were consistent with the in-situ measurement results, so the detection standard is reliable.
    • Research Article15 September 2026

      Can Artificial Seagrass Meadows Reduce Pathogenic Bacteria in Coral Reef Ecosystems- A Mesocosm Study

      Seagrass meadows provide essential coastal ecosystem functions by stabilizing sediments, enhancing water quality, and shaping nutrient and microbial dynamics. With global seagrass losses accelerating due to climate change and anthropogenic pressures, artificial seagrass (ASG) has been proposed as a nature-based alternative to mimic these functions. However, its ability to replicate biological interactions, particularly microbial regulation and pathogen suppression, remains unclear. In this study, we conducted a six-week mesocosm experiment comparing natural Thalassia hemprichii and ASG within coral reef-associated habitats in southern Taiwan. Physicochemical parameters, sedimentation rates, nutrient concentrations, and planktonic and benthic bacterial communities were analyzed. Sedimentation rates and nutrient levels did not show statistically detectable differences between natural and artificial seagrass treatments, suggesting comparable physical conditions under the experimental scale and replication. Community-level analyses showed that within the planktonic communities, ASG and natural seagrass systems differed significantly, whereas benthic communities did not exhibit statistically detectable treatment effects. Nonetheless, taxon-specific patterns revealed important functional divergences. Natural seagrass mesocosms were associated with higher relative abundance of bacterial taxa commonly link to nutrient cycling and nitrogen transformation, including members of the Alphaproteobacteria. In contrast, ASG mesocosms showed higher relative abundances of potentially pathogenic or opportunistic taxa such as Vibrio spp. and filamentous cyanobacteria (Phormidium). Overall, while ASG reproduced key aspects of the physical habitat structure, the microbial community patterns observed here suggest that artificial substrates may not fully capture the biologically mediated interactions characteristic of living seagrass systems. Within the limits of experimental duration and replication, our results indicate that ASG can approximate structural habitat functions but do not provide evidence of full functional equivalence to natural seagrass meadows. ASG may therefore contribute short-term structural habitat complexity, whereas the broader ecological functions associated with intact seagrass ecosystems likely depend on plant-driven biological interactions that were only partially represented under the present experimental conditions
    • Research Article15 September 2026

      Technical Analysis and Market Liquidity in Sale-and-Purchase Transactions of Second-Hand Oil Tankers

      In addition to using second-hand oil tankers to fulfil immediate shipping needs, shipowners can leverage price fluctuations in the tanker market to make vessel sale-and-purchase (S&P) transactions. Given that the profitability of vessel S&P transactions depends primarily on timing decisions, in this study, technical analysis was applied to identify the optimal transaction timing for 5-, 10-, and 15-year-old second-hand Aframax tankers. In a simulation, an S&P strategy based on technical analysis outperformed a benchmark buy-and-hold strategy, particularly for newer tankers, possibly due to the higher price volatility and lower market efficiency in the markets for these vessels. However, the lack of liquidity in the second-hand tanker market limited the performance of technical analysis in vessel trading, particularly for older tankers. These findings suggest that shipowners can select an appropriate technical indicator to profit from the lack of efficiency in the tanker market while avoiding the pitfalls caused by insufficient market liquidity.
    • Research Article15 September 2026

      A Resilience Early Warning Assessment of the Maritime Supply Chain: A Case Study of China’s New Energy Vehicle Exports

      Enhancing resilience through early warning is a critical strategy for mitigating disruption risks in the maritime supply chain (MSC). This study proposes a novel early warning assessment framework to determine the resilience of the MSC. It is referred to as a resilience early warning system. An evaluation index system for shipping enterprises is developed based on four dimensions: withstand capacity, adaptive capacity, learning capability, and the external environment. A resilience assessment model that uses the Bayesian best-worst method (BBWM) and the extension cloud model (ECM) is established to quantify MSC resilience. An early warning evaluation model based on a Bayesian network (BN) is constructed to dynamically link resilience indicators with risk propagation patterns. Empirical validation is conducted using the MSC of China’s new energy vehicle (NEV) exports. The proposed BBWM-ECM-BN resilience early warning model uses BNs to capture complex relationships among indicators, overcoming the limitations of traditional methods that rely on linear assumptions. Using probabilistic early warning thresholds instead of deterministic estimates enables risk prediction. The results show the following. (1) The resilience early warning level of China’s NEV export MSC is moderate. Among primary indicators, withstand capacity has a minor warning level, trending toward moderate. Adaptive capacity and External environment are at a moderate level, trending toward severe. Learning capacity is at a moderate level, trending toward minor. (2) Sensitivity analysis shows that Technology Improvement and Innovation Ability is the most influential secondary indicator (0.7360), followed by Security Risk (0.4310) and Government Risk (0.2310). This study advances theoretical understanding of MSC resilience assessment and provides data-driven tools to mitigate escalating international maritime disruption risks, supporting the stable development of China’s NEV export industry and global MSC networks.
    • Research Article15 September 2026

      Spatiotemporal Variations of Tidal Asymmetry Along the Coast of Taiwan: Characteristics and Implications

      This study presents the first systematic investigation into the spatiotemporal characteristics and evolutionary trends of tidal asymmetry along the coast of Taiwan from 2003 to 2022, employing a moving window method combined with the S_TIDE toolbox.  By quantifying the skewness of the Main Tidal Asymmetry Combinations (MTAC) and their temporal variations, the study reveals significant regional disparities between the eastern and western coasts.  The western coast is primarily dominated by the M2-M4 combination, with the northwestern region exhibiting a flood dominance pattern and the southwestern region characterized by ebb dominance.  Conversely, the eastern coast, attributed to its open topography and minimal tidal wave deformation, is mainly influenced by the O1-K1-M2 combination and displays weaker overall asymmetry.  Notably, the study identifies that specific regions, such as HsinChu and DongShi, are driven by variations in the amplitude of the shallow-water M4 constituent, leading to a significant intensification of tidal asymmetry over time.  Comparative analysis using satellite imagery demonstrates a strong correlation between shoreline evolution (e.g., erosion and accretion) and the observed trends in tidal asymmetry.  These findings elucidate the regional zonation and evolutionary trends of tidal asymmetry in Taiwan, offering a crucial quantitative scientific basis for coastal defense and adaptation strategies
    • Research Article15 September 2026

      Public-Port Throughput as an Activity Proxy for Near-Port Air Quality and Health: A Transferable Two-Scale Framework (Kaohsiung, 2017–2024)

      We developed a two-scale time series framework using monthly container throughput (20-foot equivalent units, TEU) as a port activity indicator. Applied to Kaohsiung, Taiwan (2017–2024), we related TEU to near-port NO₂ and PM₂.₅ (monthly) and air quality to outpatient respiratory diagnoses (weekly) across the 2019–2020 sulfur rules and the COVID-19 pandemic. Transfer-function models indicate TEU tends to lead near-port NO₂ by 6–9 months. Structural break tests at policy dates indicate nonsignificant changes in levels and slopes, suggesting gradual rather than abrupt shifts in the activity–pollution linkage. Weekly two-pollutant distributed-lag Poisson models estimated relative risks (lags 0–8) per interquartile range (IQR) increase. For acute upper respiratory infection, NO₂ was associated with higher risk (RR, 1.184; 95% CI, 1.032–1.358), whereas PM₂.₅ estimates were null (RR, 1.032; 95% CI, 0.917–1.161). Pre-specified negative-control endpoints yielded mixed-sign associations, which were interpreted as residual design noise rather than a coherent nonrespiratory signal. Combining TEU statistics with meteorology-adjusted NO₂ helps screen whether maritime policies and operational changes coincide with air-quality shifts and respiratory risk. This approach requires only publicly reported TEU statistics, routine air-quality monitoring, and syndromic outpatient counts, and is therefore feasible in settings where AIS-based ship-activity metrics or detailed emissions inventories are unavailable.
    • Research Article15 September 2026

      Identifying the Causality and Criticality of Factors Influencing the Promotion of Asia Island-hopping Cruise Tourism in Taiwan

      Following the COVID-19 pandemic, the global tourism industry has steadily recovered since 2022. Island-hopping cruises have gained increasing attention for enhancing regional connectivity and diversifying marine travel experiences; however, their development in Asia remains limited compared with that in Europe and the Caribbean due to fragmented policy coordination, inadequate port infrastructure, and uneven technological readiness. Although Taiwan possesses a geographic advantage and can serve as a strategic hub linking Asian island destinations, systematic planning and stakeholder coordination remain insufficient, resulting in unclear mechanisms that drive or constrain island-hopping cruise tourism. Existing studies mainly focus on market demand or passenger behavior, while limited attention has been paid to the system-level causal structure and critical driving factors. To address this research gap and corresponding industrial challenges, this study identifies the key influencing factors and their interrelations from Taiwan’s perspective using a hybrid multi-criteria decision-making approach integrating the Fuzzy Decision-Making Trial and Evaluation Laboratory (FDEMATEL) and an FDEMATEL-based Analytic Network Process (FDANP). The framework was established through political, economic, social, technological, environmental, and legal (PESTEL) analysis and validated using a modified Delphi method. The results indicate that political and technological dimensions are core causal drivers, while government-driven policies for cruise industry development represent the most critical criterion. This study elucidates the causal structure among factors and provides actionable implications for policymakers to strengthen policy integration, enhance technological innovation, and promote sustainable island-hopping cruise tourism in Asia, with Taiwan serving as a strategic reference context rather than representing the entire Asia-Pacific region.

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