Journal of Sea Research最新文献

As global concerns about carbon emissions mount, Automated Guided Vehicles (AGVs) have made a significant transition from reliance on petroleum fuel to predominantly utilizing electric power. However, in past port settings, the majority of Automated Guided Vehicle (AGV) control strategies have overlooked the impact of AGV charging and have not taken energy consumption into account. Furthermore, the AGV's electricity consumption is uncertain. Recognizing AGVs as the primary energy-consuming equipment in automated dockyards, this paper introduces a novel AGV resilient scheduling problem that integrates charging constraints and formulates a corresponding model that encompasses these limitations. Building upon established loading or unloading tasks, this model allocates AGV scheduling, including charging requests, to adhere to battery constraints and minimize AGV energy consumption costs. Moreover, a mathematical method based on Large Neighborhood Search (LNS) has been developed to address this issue. Finally, numerical experiments were conducted at a genuine large-scale automated port in China, meticulously analyzing the layout of charging areas, the establishment of charging thresholds, and the deployment of AGVs, thus highlighting the paramount significance of the operational framework of automated ports.

Coastal zones play a crucial role in China's marine economy and ecological security. However, the intensification of the human activities has increased the burden on the ecosystems and carbon storage capacity of the coastal zones. In this pursuit, a case study was conducted in Lianyungang, wherein the carbon stocks were assessed using ArcGIS and InVEST model in view of the carbon neutrality targets. Remote sensing data for the years 2010, 2015, 2018, and 2020 was analyzed to assess the carbon storage capacity in the coastal zones of Lianyungang, and the causes of variation and the spatial evolution patterns were studied. The results showed that the carbon storage capacity of the coastal zones of Lianyungang showed a progressive decline with time. The carbon stock in 2020 was 6.245 × 10⁶ TC (measured by CO₂), which was more as compared to that of a decade ago. Based on estimation of the carbon stocks, several ecological restoration strategies were proposed for coastal zones of Lianyungang. The study area was divided as: ecological control space, ecological restoration space and ecological governance space. Ecological management requirements and suggestions were proposed for each type of space. Our research not only contributes to the sustainable management of coastal zones of Lianyungang, but also provides a scientific basis for achieving the carbon neutrality targets.

Accurate water depth estimation is crucial in coastal environmental management, resource exploration, and ecological protection. Traditional water depth measurement methods are often time-consuming and costly, especially in vast sea areas where their application is limited. However, with the rapid development of remote sensing technology, particularly the widespread use of high-resolution satellite imagery, water depth remote sensing has emerged as a more efficient, economical, and widely applicable solution. In this study, we utilized Sentinel-2 satellite data and applied various algorithms to accurately estimate water depth in the Nanshan Port area. The results showed that the Gradient Boosting Machine (GBM) model excelled in monitoring shallow water and coastal environments, effectively addressing challenges such as light attenuation and water scattering in turbid waters. Compared to traditional methods, GBM-generated predictions were smoother and more detailed. This study not only demonstrates the significant potential of satellite remote sensing for water depth measurement but also points to future directions for algorithm optimization and the integration of remote sensing technologies. It is expected to bring revolutionary progress to oceanic scientific research and coastal management.

Fisheries activites and oceanographic conditions have a strong relationship. Understanding the complex interplay between fisheries and oceanographic conditions is essential for effective fisheries management. The aim of this research is to analyze the in-situ fishing activities with oceanographic conditions in the Fisheries Management Area (FMA) or WPP-NRI 718 located in the Aru Sea and its surroundings. The main data source is from open global data ship tracking and oceanographic conditions from satellite data. In general, fishing is conducted around the waters of Aru Island. The fishing grounds are strongly influenced by a combination of environmental factors, including sea surface temperatures, chlorophyll-a (Chlor-a) concentrations, sea surface height, and current velocities. A decrease in fishing patterns around Aru Island waters occurs in the eastern season, where fishing tends to occur in the western region (near Timor-Leste). Based on the oceanographic conditions, fishing tends to occur in regions with warmer conditions ranging from 27 to 29 °C, moderate Chlor-a (1.02–3.01 mg/m³), a relatively high surface height (0.17–0.32 m), and slow surface currents.

Artificial reefs are basic fishery facilities for marine habitat conservation and construction. In order to enhance fishery resources and restore the ecological environment in Laizhou Bay, where is an important fishing ground in China, an assembly-type oyster reef was designed based on the biological community, water depth and sea current in Laizhou Bay. This paper studied the effect of filling oyster shell in the assembly-type oyster reef on the flow field distribution by computational fluid dynamics (CFD), optimized the structure of reef, and presented the construction deployment of reef habitat and assessed potential of carbon fixation of oyster reefs. Indexes of upwelling, slow flow and vortex were chosen to describe the flow field effect of oyster reefs. The distribution characteristics of flow field under three types of filling oyster shell were analyzed: filling no shell (UAR), filling shells with an 83.6 void ratio (OAR), and filling shells with a 0 void ratio (FAR). The results showed that the upwelling, vortex and slow flow efficiency indicators of the OAR had obvious advantages compared with the other two filling methods, and the efficiency indicators of OAR with the spacing between basic elements of 280 m and deployment angle of 0° were higher than the others. Finally, according to the study result of filling method, spacing and deployment of oyster reef, the assessment showed that reefs could fix 2178.9 t carbon by themselves on the basis of national marine ranching demonstration area regulations in China.

Indonesian coastal waters include several marine megafauna biodiversity hotspots. Several fish populations of ecological and socio-economic importance, such as elasmobranchs (sharks and rays), have experienced rapid decline due to unsustainable human activities, primarily overfishing. Small-scale fisheries (SSF) are currently exempt from governmental fisheries management measures despite contributing a significant proportion of a total catch. The Generalised Additive Models were used to investigate the effect of variations in oceanographic parameters of the Teluk Penyu fishing ground, south of central Java, on the magnitude of Mobulidae (Mobula spp.) catch based on its landings data over ten years (2009–2018) from one of Indonesia's largest ports, Cilacap, Central Java, Indonesia. Mobulidae catch from Teluk Penyu fishing ground was generally higher from June to November when the water exhibited relatively high sea surface salinity (sal >34.1 ‰), chlorophyll (0.32–0.45 mg/m³), and nitrate (nit >0.0045 mg NO₃/m³), water speed (>0.29 m/s) and eddy kinetic energy (>0.04 m³/s²) levels, and relatively low sea surface temperature (<28 °C), oxygen (<0.182 mg O₂/m³) and sea surface height (<0.9 m) levels than the other months of the year. This study reveals that satellite Earth Observation (EO) data provided a preliminary relationship between oceanographic conditions and the amount of catch for developing more effective management and conservation measures for endangered species like Mobulidae. Utilizing EO data may also be applied to help inform much-needed ecosystem-based management measures, including habitat protection and bycatch reduction for conserving endangered Mobulidae species in the Southeast Indian Ocean. The in-situ onboard ocean observation and temporal species-specific catch data will greatly complement the current work.

The La Niña event not only affected global ocean dynamics but also marine productivity. Due to its importance to the life of organisms and ecosystems, the biophysical aspects should be analyzed. One of the important regions in the eastern region of the Indian Ocean is located in the upwelling system and central marine biodiversity. The study aims to investigate several parameters, including SSTs, dissolved oxygen levels, nitrate distribution, and Chlor-a concentration, which are combined with ocean currents. These parameters are then analyzed in the period 2020 to 2022, which is La Niña condition. Based on the results, significant changes occur in SST during the first transitional season of 2022, where the increase reaches 1–4 °C. There was an increase in La Niña during this period. For marine productivity parameters, the recorded DO is in the range of 197 to 218 mmol/m³, nitrate with a value range of 0 to 0,02 mmol/m³, nanoplankton with a value range of 0 to 0.03 mg/m³, and Chlor-a with a value range of 0 to 4 mg/m³. We also found that changes in ENSO events affect the productivity of the Eastern Region of the Indian Ocean, especially in the Chlor-a parameter, where the occurrence of La Niña extreme is the most important parameter.

This study investigates the temporal variability of mesoscale eddies in the Bay of Bengal (BoB) over a 29-year period (1993–2021) using satellite altimeters. High-resolution daily sea level anomaly data are considered to identify the mesoscale eddies in the BoB utilizing py-eddy-tracker, an automated eddy detection and tracking method. Wavelet coherence analysis was conducted to find a statistically significant relation between eddy properties and climate indices. The findings indicate that anti-cyclonic eddies are more susceptible to the consequence of the Indian Ocean Dipole (IOD) and El Niño Southern Oscillation (ENSO) than cyclonic eddies. Additionally, the joined impact of ENSO and IOD conceivably alters eddy activities across the BoB, as the second downwelling coastal Kelvin wave (dCKW) were absent. The mesoscale eddies exhibit correlations with climate indicators, suggesting that eddies get stronger during La Niña and negative IOD years and get weaker during El Niño and positive IOD years. This is because La Niña and negative IOD events intensify the second dCKW, while it weakens or becomes completely absent during El Niño and positive IOD years. Random Forest model was used to compare the influence of ENSO and IOD on the forecasting performance of the eddy properties. It was demonstrated that a unique positive IOD (+IOD) negatively affects the forecasting of eddy properties when using Sea Surface Temperature (SST) and SST anomalies. The findings bear importance in verifying and confirming the interactions between the ocean and climate.

The analysis of ocean eddies in the marginal ice zone via remote sensing and modeling data is a challenging task. However, it is of crucial importance for various scientific applications and anthropogenic activities in the Arctic. Models often struggle to accurately represent eddies near the MIZ due to the intricate nature of sea ice-ocean interactions, unresolved small-scale processes, and coarse resolution. Nevertheless, combining the information provided from both SAR and model data offers promising results that can potentially improve eddy detection accuracy near the MIZ. Furthermore, accurate characterization of the spatial and temporal variability of eddies near the MIZ demands a holistic approach that incorporates multi-platform observations, including numerical models and remote sensing data. This study demonstrates a specific test case on the intercomparison of the eddy signatures located in the MIZ in the Fram Strait based on remote sensing SAR scenes and Lagrangian modeling data from the two global oceanographic reanalysis GOFS 3.1 and GLORYS 12 V1. The study specifically displays the strong agreement in the eddy polarity and synchronism with reality, as well as differences in spatial scales and location of eddy centers. Overall, the obtained results support the further use of the presented approach for studying the eddies in the MIZ regions in the Arctic.

The North Frisian Wadden Sea (NFWS), an open tidal basin within the UNESCO World Heritage Wadden Sea, is characterized by its barrier systems, tidal inlets, intertidal flats, and estuaries. Unlike its East Frisian and Dutch counterparts, the NFWS is underexplored in terms of residual sediment and flow transport pathways—knowledge crucial for coastal conservation and nature-based protection. These pathways are a product of complex interplay between tides, winds and waves that together shape the morphology of the NFWS. This study investigates these interactions using a high-resolution process-based model to perform a representative period simulation derived through a novel unfiltered-reduction technique. Our results reveal an anticlockwise residual flow circulation in the back-barrier region, which was not discernible in the residual sediment pathways. Waves primarily dictated sediment transport over intertidal flats, showing high variability in transport direction under energetic conditions. The coastline orientation and fetch size favored southward wavedriven sediment transport, opposing the northward residual flow transport driven by tidal propagation. A dynamic residual divergence pattern in the nearshore region of the barrier islands is also revealed for both sediment and flow, which moves alongshore during energetic events. The discussion compares these patterns and their implications with earlier local measurements, conceptual pathways, and different systems globally to provide a comprehensive overview of the transport dynamics in the NFWS.