Fresh Water Studies Commons^™

Diel Variations In Abundance Of Viral, Picoplankton, And Nanoplankton In Coastal Waters Of Taiwan In Spring, Patrichka Wei-Yi Chen, Madeline Olivia, Vladimir Mukhanov, Ufimtseva Margarita, Liashko Tatiana, Sakhon Evgenii, Supriyadi Supriyadi, Intan Dwi Puspitasari, Arpita Ghosh, An-Yi Tsai

Journal of Marine Science and Technology–Taiwan

The diel variations of viruses (< 0.2 μm), picoplankton (0.2-2 μm; heterotrophic bacteria, Synechococcus spp., and picoeukaryotes), and nanoflagellates (2-20 μm; heterotrophic and pigmented nanoflagellates) were examined for 2 days with approximately 4 h of temporal sampling in the spring of 2024 in coastal surface waters of the subtropical western Pacific. The abundance of bacteria did not follow a consistent diel pattern, and viral abundance was positively correlated with bacterial abundance. Synechococcus spp. was found to grow during the light period and with peak abundance at night, exhibiting a remarkably diel pattern; however, the pattern was opposite in picoeukaryotes. In the size-fractionation experiments, after 32 h of …

New Insights Into Decapod Chemical Communication: A Focus On The Hydrothermal Vent Crab Xenograpsus Testudinatus, Jishnu Panamoly Ayyappan, Mark June S. Consigna, Li-Chun Tseng, Jiang-Shiou Hwang

Journal of Marine Science and Technology–Taiwan

Chemical communication in decapod crustaceans has been extensively studied for over 150 years, with most of the research focusing on sex pheromones. These crustaceans inhabit chemically complex environments and rely on diverse chemical signals for essential behaviors such as mate recognition, predator avoidance, and social interaction. This review synthesizes key findings from studies on shrimp, crayfish, lobsters, and crabs, the most well-documented taxa in crustacean chemical ecology. Various appendages, including the first and second antennae, mouthparts, and walking legs, are involved in chemosensory detection. Special emphasis is placed on chemical communication in extreme environments such as hydrothermal vents (HVs), with …

Apply Cluster Analysis To Improve Interpretation Of Ert Images, Yin-Chun Hung, Yu-Xiang Zhao

Journal of Marine Science and Technology–Taiwan

The completeness and accuracy of collecting and investigating geotechnical and marine engineering geological conditions are key to the success or failure of engineering development. Traditional marine engineering and geotechnical surveys often require the assistance of geophysical methods to fully present the geological conditions. Electrical Resistivity Tomography (ERT) is an advanced geophysical method that produces accurate cross-sections of underground resistivity. Although 2D ERT has been widely used in geotechnical engineering and marine engineering, many uncertainties remain hidden behind the vivid and colorful resistivity profiles. To apply 2D ERT profiles effectively in geotechnical and marine geological surveys and monitoring, it is essential …

Geo-Chemical Fractionations Of Phosphorus In Sediments Of Thuy Trieu Lagoon And Cam Ranh Bay, Vietnam, Phu H. Le, Ngoc H. Pham, Dung T. Le, Tuan Linh T. Vo, Binh V. Tran, The V. Ho

Journal of Marine Science and Technology–Taiwan

The geochemical fractions of phosphorus (P) and its bioavailability in sediments of Thuy Trieu Lagoon and Cam Ranh Bay were investigated. Twenty-four surface sediment samples were collected in the dry season (Jun 2024) and the rainy season (Oct 2024). A sequential extraction procedure was applied to identify the phosphorus (P) fractions in sediments, including Exchangeable P (Ex-P), iron-bound P (Fe-P), aluminum-bound P (Al-P), calcium-bound P (Ca-P), and residual P (Res-P). Total P (TP) ranged from 214.9 to 2365.2 µg.g^-1, and the Ca-P fraction was the dominant chemical form in sediments. Based on the results of Pearson correlation and …

Beyond Basic Needs : Exploring The Antecedents And Outcomes Of Seafarers’ Well-Being, Chian Liou, Cheng Kuo Sung, Kimberly Hsiu-Chin Lee, Jiunn Liang Guo

Journal of Marine Science and Technology–Taiwan

Given the importance of seafarers’ mental health and the limited literature on this topic, this study aims to explore the causes and consequences of seafarers’ well-being. A questionnaire survey was conducted, and the data were analyzed using structural equation modeling and hierarchical regression analysis. Consistent with the predictions of the happy and productive worker thesis, this study found that the more satisfied the seafarers are with the shipping company’s seafarer policy, the higher their well-being tends to be, leading to a more positive work attitude. Interestingly, the study found that a company effect is significantly present in this correlation; that …

Empowering Shipping Management Competence With Artificial Intelligence: A Strategic Approach To External Environmental Volatility, Yu-Kai Huang, Cheng-Hsien Hsieh, Chi-Chang Lin, Yu-Tzu Chang, Yu-Chao Cheng

Journal of Marine Science and Technology–Taiwan

The shipping industry is undergoing significant transformation with advancements in artificial intelligence (AI), yet challenges remain in effectively adopting AI technologies. This study addresses the key concerns influencing AI adoption in shipping management. Using the Analytic Hierarchy Process (AHP) integrated with the PEST model, an evaluation framework was developed to assess AI applications in shipping companies. Based on expert input collected through the Delphi method, four constructs and twelve criteria were identified, with the 'Technological' dimension being the most critical. 'Robustness,' 'Costs,' and 'Data quality' emerged as the top factors affecting AI implementation. The framework offers practical insights for shipping …

Comparative Evaluation Of Deep Learning Models For Predicting Skipjack Tuna (Katsuwonus Pelamis) Catch Based On Climatic Factors, Peng Ding, Hui Xu, Xin Zhuang, Yan-Lun Wu, Fengyuan Shen, Yujie Xiao, Jiensi Zhulidezi, Wei-Yu Lee

Journal of Marine Science and Technology–Taiwan

To investigate the impact of climatic factors on skipjack tuna catch, this study collected and analyzed annual global skipjack tuna catch data spanning from 1960 to 2021, along with corresponding monthly data for the key indicator of El Nino events (Niño1+2, Niño3, Niño4, and Niño3.4), the Southern Oscillation Index (SOI), the North Atlantic Oscillation (NAO), the Pacific Decadal Oscillation (PDO), the North Pacific Index (NPI), and the global sea-air temperature anomaly index (dT). The optimal lag years of climatic factors were identified by selecting the maximum absolute cross- correlation coefficients. Subsequently, the predictive performance of LSTM, BiLSTM, and CNN-BiLSTM models …

Effects Of Train-Ship Direct Transshipment On Container Terminal Operational Efficiency And Energy Consumption: From A Scheduling Perspective, Yiying Du, Yaozong Wang, Zhongzhen Yang

Journal of Marine Science and Technology–Taiwan

On-dock rail integration positions terminals as critical hubs for rail-sea transshipment, which necessitates efficient scheduling for rapid container transfers. Given the strict schedules and batch arrival of railway containers, in this study, we propose a train-ship direct transshipment (TSDT) mode to eliminate nonproductive yard rehandling. To comprehensively evaluate the impact of the proposed mode on terminal handling operations, we developed an operational scheduling model for the entire process of the simultaneous loading of yard containers and railway-handling area (RHA) containers. The model comprises two stages. Stage 1 models the pre-reshuffling operations in the yard before loading, and Stage 2 implements …

Key Success Factors In Using The Lifting Method To Construct A Steel Bridge Pylon, Ming-Chao Su, Hui-Ping Tserng

Journal of Marine Science and Technology–Taiwan

Constructing the inclined steel pylon of cable-stayed bridges is challenging because of the pylon’s height, spatial limitations, and safety concerns. To address these challenges, this study developed a modular lifting method that can enhance the efficiency and precision of pylon construction. The proposed method involves using rotation jigs to temporarily assemble the pylon, horizontal positioning on temporary supports, and synchronized lifting through computer-controlled hydraulic systems. Field implementation on a large-span bridge project revealed that compared with the traditional method, the proposed method resulted in higher welding quality, lower risks associated with great-height operations, and a shorter on-site assembly time. The …

Deep Learning-Based Model For Automated Prediction Of Coastal Changes: A Robust Approach To Environmental Forecasting, Tsair-Fwu Lee, Chu-Ho Chang, Chin-Shiuh Shieh, Chih-Hsien Wu, Jen-Chung Shao, Chien-Liang Chiu

Journal of Marine Science and Technology–Taiwan

The coastline stands as a critical domain encompassing industry and the environment. The escalating global warming, leading to elevated sea levels and intensified wave-current interactions, has given rise to substantial coastal erosion. This predicament, in conjunction with excessive human development and Taiwan's coastal areas' extreme climatic impact, accentuates the perceptibility of coastal beach alterations. As a result, coastal erosion has emerged as a pressing issue necessitating resolution. Traditional methodologies for assessing coastline changes have conventionally relied on manual measurements. However, owing to the fluctuating distance of coastlines, influenced by tidal patterns, extended measurement processes over several months are susceptible to …

Hydrographic Influences On Seasonal Variations In Zooplankton Communities Of Taiwan Bank (Southern Taiwan Strait), Bor-Shyr Chen, Frank Paolo Jay B. Albarico, Mark Ariel D. Malto, Aiza D. Gabriel, Chiu-Wen Chen, Cheng-Di Dong

Journal of Marine Science and Technology–Taiwan

Understanding the factors that control ocean productivity is crucial in fisheries management. Taiwan Bank, located between the Taiwan Strait and the South China Sea, is a highly productive ecosystem due to upwelling events. The total zooplankton community (holozooplankton and merozooplankton), diversity, seasonal changes, and environmental drivers remain unexplored despite its productivity. This study evaluates the seasonal and vertical environmental dynamics in the Taiwan Bank and their impacts on the zooplankton community structure. We collected zooplankton and basic water parameters in March, July, and September 2017 at 5, 25, and 50 meters. We recorded significant seasonal changes in zooplankton composition and …

Model Performance For Predicting Trends And Analyzing The Impacts Of Sea Surface Temperature Changes In The Gulf Of Thailand, Tanatpong Udomchaipitak, Nathaphon Boonnam

Journal of Marine Science and Technology–Taiwan

This study focuses on assessing and improving the predictive performance of sea surface temperature (SST) in the Gulf of Thailand under unique environmental challenges. Data from the Hybrid Coordinate Ocean Model (HYCOM) were utilized, covering the period from July 1994 to June 2024 at depths ranging from 0 to 30 meters. After cleaning the data using the Interquartile Range (IQR) method, the processed dataset was tested using four models: Recurrent Neural Network (RNN) architectures, including Long Short-Term Memory (LSTM) and Gated Recurrent Unit (GRU), as well as Convolutional Neural Networks (CNNs). Model performance was enhanced by tuning the parameters over …

Dam It All: A Multi-Scalar Investigation Into The Ecological Role And Function Of Beaver Dams, Kenneth Larsen

Dissertations, Master's Theses and Master's Reports

The central theme of this dissertation is ecological scaling, which examines how small, localized features, such as beaver ponds, contribute to large-scale watershed processes and how different modeling approaches at various scales reveal distinct insights. Through a combination of probabilistic modeling and high-resolution empirical research, this work demonstrates that small ponded systems, particularly those created by beavers (Castor canadensis), serve as critical biogeochemical control points, whose contributions to sediment and nutrient dynamics have been historically underestimated.

In Chapter 1, I contextualize this research within the broader fields of freshwater ecology, watershed modeling, and ecological restoration. I introduce the …

Shifting Waters: A 41-Year Time-Series Analysis Of Surface Water Change In The Prairie Pothole Region, Madison Dejarlais

Electronic Theses and Dissertations

The Prairie Pothole Region (PRR) is a landscape defined by a dynamic surface water system, with wetlands, lakes, and rivers playing critical roles in supporting biodiversity, regulating floods, and maintaining hydrological balance. This study conducts a time-series analysis of surface water change in the PPR from 1984 to 2024, using remote sensing tools including Google Earth Engine, ArcGIS Pro, and ENVI. 41 annual surface water presence rasters were compiled into a cumulative dataset, allowing for both year-to-year comparisons and broader trend analysis. Results indicate that the presence of surface water in the PPR has not followed a simple linear trend. …

Evaluation Of The Maneuverability Of An 85m Fishing Trawler (Focusing On Dynamic Stability), Chun-Ki Lee, Su-Hyung Kim

Journal of Marine Science and Technology–Taiwan

Most fishing vessels are less than 100 meters in length, so IMO maneuverability standards do not apply. As a result, studies on the maneuverability of fishing vessels are considerably fewer compared to those on merchant ships. However, with technological advancements, the size of fishing vessels continues to grow, and as more fishermen are on board, accidents could lead to fatal casualties. In response, the authors determined that research on the maneuverability of fishing vessels is urgently needed. Thus, the authors conducted a maneuverability evaluation on a fisheries training vessel with the hull shape of a fishing trawler, 85 meters in …

A Hybrid Image Filtering Approach For Improving Edge Detection Of Riverbed Particles With Complex Textures, Po-Wei Lin, Hsun-Chuan Chan

Journal of Marine Science and Technology–Taiwan

The distribution of particle size in gravel-bed rivers affects the flow condition, sediment transport, and river morphology. However, conventional particle size analysis is laborious and time-consuming. To enhance the efficiency of particle size analysis, image-based methods have been widely explored, but complex particle textures increase the difficulty in identifying particle edges during image analysis. This study develops a filtering approach based on the rolling guidance filter and leverages the differences in grayscale gradients between particle edges and textures to design a guidance image tailored for the rolling guidance filter. This design enables the filter to preserve particle edges while smoothing …

Comparison Of Canopy Materials To Improve The Performance Of Sea Anchors Used For Fishing Operations, Namgu Kim, Su-Hyung Kim, Yoo-Won Lee, Kyung-Jin Ryu

Journal of Marine Science and Technology–Taiwan

Sea anchors used for fishing operations help improve catch rates by stabilizing vessel drift speeds to match tidal or ocean currents. The underwater resistance experienced by a sea anchor's canopy significantly impacts its performance, yet there has been limited research on canopy materials. This study investigates how different canopy materials can enhance sea anchor performance. Specifically, we tested sea anchors made from three fabrics: the currently used polyamide (PA) material, PA material with increased yarn density in the weft direction, and polyester (PES). Using Korean national standards, we compared the yarn density, weight, water absorption capacity, drying rate, air permeability, …

Research On Ship Track Prediction Based On Ipso-Cnn, Xiangen Bai, Nuo Chen, Xiaofeng Xu

Journal of Marine Science and Technology–Taiwan

With the rapid development of the global economy, international imports and exports have become increasingly important. Timely and effective tracking and prediction of ship trajectories are important in the face of complex maritime traffic. Based on AIS data, this study establishes a ship trajectory prediction model combining improved particle swarm optimization (IPSO) and a convolutional neural network (CNN) that uses the ship's historical navigation trajectory data to predict the future navigation trajectory. The historical ship trajectory data of the Port of Ningbo-Zhoushan were selected for the experiment, and the IPSO-CNN model experiment results were compared with those of other models. …

Investigating The Thermal Stratification Patterns Of A Shallow Polymictic Boreal Shield Lake And The Effectiveness Of Models In Predicting Shallow Lake Thermal Profiles, Matthew Roberts

Theses and Dissertations (Comprehensive)

Thermal stratification is a core process of lakes which plays a critical role in shaping the ecological dynamics of lakes, influencing major processes like nutrient cycling and oxygen availability. For shallow polymictic lakes, thermal stratification patterns present some unique differences due to the complex and variable nature of these lakes. In this thesis, I examined thermal stratification in a shallow polymictic lake in northwestern Ontario during the ice-free season of 2019 to investigate the frequency, duration, and driving factors of thermal stratification. The lake underwent 146 separate stratification events, with a median duration of 2 hours per event, with a …