Bosphorus Research Articles

Black Sea Rising

_ Saipem’s flagship vessel Castorone was contracted to start work this summer on Turkey’s offshore deepwater Sakarya gas field while neighboring Romania prepared to enter Phase 2 of its Neptun Deep gas project. Blessed with some of the same source rock as the hydrocarbon-prolific Caspian Sea (they were one sea in the geologic past), the Black Sea has long been regarded as a frontier basin of great promise, but with unique challenges—earthquakes, sheer slopes plunging to 2200-m depths where sediments are unstable, its bottom-water harbors H2S instead of oxygen, and complex life is nowhere to be found. Straddling Europe and Asia, the Black Sea is surrounded by Turkey, Russia, and other remnants of the USSR and the czarist empire before it: Romania, Bulgaria, Ukraine, and Georgia. There is also only one way in and one way out, via Istanbul and the Bosphorus Strait whose width varies from 3.7 km (2.3 miles) to 750 m (2,450 ft). The Bosphorus has long been the southern export route for Russian (and Soviet) oil loaded on tankers at Novorossiysk for transport to the Mediterranean, and over years the Black Sea has become crisscrossed by gas pipelines, most notably the Blue Stream and TurkStream, which seemingly cemented Turkey’s role as a transit state and major consumer of Russian gas. Times, though, have changed. With energy security through diversity of supply now top of mind, Romania and Turkey are driving their own exploration and production projects to identify and develop deepwater gas reserves to supply domestic needs as they simultaneously strategize to become future exporters through such infrastructure as the Trans Anatolian Natural Gas Pipeline (TANAP) and liquified natural gas (LNG). Ukraine and Russia, meanwhile, are the wildcards in the region, considering that the largest deepwater deposits in the Black Sea are believed to lie in the unexplored waters of Ukraine. Neptun Deep To Position Romania as Largest EU Gas Producer In June 2023, 50/50 partners Austria’s OMV Petrom and Romanian state-owned Romgaz Black Sea Ltd. took a final investment decision (FID) to proceed with their $4.4-billion Neptun Deep gas project, which data and analytics provider Wood Mackenzie (Woodmac) notes, will make Romania the largest gas producer in the EU. Neptun Deep is the first deepwater development on the Romanian shelf which is part of the northwestern Black Sea Continental Shelf (Fig. 1). According to Woodmac, it was the EU’s largest upstream FID in 2023. With an estimated 100 Bcm in reserves, Neptun Deep aims to produce first gas in 2027 from two fields: the deepwater Domino gas field at 1000-m depth and the shallow-water Pelican Sud (South) at 120-m depth. The project’s 10 wells will tie back to an unmanned shallow-water platform and will deliver 8 Bcm/yr (775 Mcf/D) of gas at plateau for about 10 years (Fig. 2). Neptun Deep’s plateau output will boost OMV Petrom’s production mix to 70% gas from the current 50%, a goal the Austrian operator has set for itself by 2030.

Assessing the Impact of Ship-Sourced Marine Pollution on Filyos Port

In 2021, Turkiye launched the Filyos Valley Project, a strategic initiative with the potential to serve as both a central hub for the transfer of Central Asian oil to the West and as a logistical bridge between China and Europe. Located near the city of Zonguldak in northern Turkiye, this project encompasses a range of logistical components, including the extensive and high-capacity Filyos Port, which is the third-largest port in the country. The port is situated in close proximity to the Sakarya gas field in the Western Black Sea, Turkiye's largest natural gas production area, and currently serves as a base for natural gas drilling ships and their support vessels. Filyos Port plays a crucial role in Turkiye's energy security due to its strategic location near the Istanbul Strait, a key convergence point for maritime traffic in the Black Sea. However, this proximity also poses a significant risk; pollution from a maritime accident along the approach routes to the Strait could severely disrupt the port's operational capabilities. This study aims to analyze the behavior and spread patterns of ship-sourced oil pollution near Filyos Port and to determine the timeframe within which the port would be exposed to such pollution. This research offers a comprehensive framework for port authorities to develop effective contingency plans, ensuring operational sustainability and enhancing the region’s energy security by mitigating the risks of marine pollution.

Late Pleistocene–Holocene palynology and paleoceanography of İmralı Basin, Marmara Sea: Pollen-spore, dinoflagellate cyst and other NPP zonations

The Marmara Sea is the oceanographic gateway that links the hypersaline Eastern Mediterranean Sea with the hyposaline Black Sea via Straits of Dardanelles and Bosphorus, respectively, and also occupies a transitional vegetation and climatic regime between the Mediterranean and Euxinic phytogeographic ecosystems. Recent palynological studies of long cores from the shallow İmralı Basin perched on the southeastern slope of the Marmara Sea reveal that major paleoecological changes accompanied the isolation and reconnection of the Marmara Sea during the last two Pleistocene glacial–interglacial cycles. Here, we use data primarily from two İmralı Basin cores to determine new quantitative zonations for the pollen-spore, dinoflagellate cyst (dinocyst) and other non-pollen palynomorph (NPP) assemblages in sediments representing the last ∼30 cal ka. A gap in one core is closed using data from three short gravity cores. Twenty-four radiocarbon ages and 20 correlation-ties for sapropel and ash layers from these five cores provide an essentially complete record for the past 30 cal ka. Use of a full suite of palynomorph data (pollen and spores, fungal spores, dinocysts and other phytoplankton, aquatic parasites/saprophytes, zoo-planktonic and zoo-benthic NPPs) shows for the first time that fluctuations in aquatic palynoassemblages during the glacial periods are more complex than simple salinity or temperature responses. The changes involve food web-level turnovers in trait- and size-based food web components in which potential parasites/saprophytes appear critically important.Pollen stratigraphies reveal a significant loss of Euxinic tree taxa by MIS 3c, with only partial recovery in MIS 1. The Euxinic forest elements are replaced by cultivars and other indicators of anthropogenic influences during the MIS 1 that is also marked by a dry interval and corresponding in part with the 4.2 cal ka Eastern Mediterranean Drought Event. The dinocyst zones for the last ∼30 cal ka show a clear turnover from assemblages dominated by brackish Ponto–Caspian taxa to marine assemblages at ∼11.7 cal ka. This phytoplanktonic signal lags slightly behind (a) the vegetation and shift in the other NPP commencing ∼13.2 cal ka, the initial marine incursion at 13.8 cal ka, and the arrival of coccolithophores at ∼13 cal ka. Comparison to published MIS 6 and 5 data reveals higher MIS 2–1 species diversity, reappearance of the MIS 6 marker Impagidinium inaequalis, and the emergences of Pyxidinopsis psilata f. quadrata, cf. Boreadinium breve, and Peridinium spp. of Brenner 2005. The pre-reconnection microbiota is dominated by the unicellular alga Sigmopollis, spikes of colonial Pediastrum algae, the saprophytes/parasites cf. Multiplicisphaeridium and Chytridiomycota. This microbiota is displaced by the post-reconnection assemblage dominated by Botryococcus coenobia, various Platyhelminth egg capsules and ostracod lining-types that persist through the Holocene. A distinctive transitional microbiota with Discocotyle-type turbellarian egg capsules marks the Bølling–Allerød warming, followed at ∼13.3 ka by a marine assemblage with micro-foraminiferal linings and crustacean eggs. The interglacial marine phase of MIS 1 in İmralı Basin has much higher dinocyst species diversity than MIS 5e, reflecting Neolithic impacts (agriculture, land clearance) and expanded shipping trade. Initial marine flooding in the Marmara Sea during both interglacials are marked by sapropel deposition but variations of ravinement surface erosion, and marine deep water residence time in a stratified Marmara Sea are potentially important factors underlying hypoxia/anoxia and sapropel deposition.

Effect of the low sulphur regulations of maritime fuels on ambient air quality: a case study in the Bosphorus strait

Effect of the low sulphur regulations of maritime fuels on ambient air quality: a case study in the Bosphorus strait

Seasonal and Inter-annual Variability in the East of the Sea of Marmara Water Masses by Temperature and Salinity Time Series

This study mainly aims to examine the relationship between oceanographic properties and climate change in the conjunction of the Istanbul Strait (IS), specifically in the east of the Sea of Marmara (SoM) via evaluating observational temperature and salinity profiles at six stations with monthly atmospheric pressure and air temperature during the period of 1997-2010. The annual cycle of temperature and salinity of the upper and lower layers in the east of SoM have strong seasonal variation: The upper layer temperature rises during summer while decreases in winter. Conversely, the lower layer temperature is higher in winter compared to spring and summer. Additionally, salinity levels in the upper layer are higher in winter and lower in summer, whereas in the lower layer, the pattern is reversed, with lower salinity in winter and higher salinity in summer. In this context, linear trend analyzes are calculated by using monthly time series of temperature and salinity and compared with the trends of atmospheric conditions and the surrounding seas. The average temperature trend in the east of the SoM is increase of 0.067°C/y in the upper layer and increase of 0.028°C/y in the lower layer during this period. The salinity trend is increase of 0.105 psu/y in the upper layer and increase of 0.012 psu/y in the lower layer. The air temperature trend is increase of 0.086°C/y, and the air pressure trend is decrease of 0.034 mbar/y. These values closely align with those observed in the surrounding seas. The air temperature and upper layer temperatures are consistent with each other in terms of both long-term series and trend values.

The impact of vertical mixing on the variability of salinity in the Black Sea pycnocline: Role of winter convection, vertical shear and mediterranean waters injections.

Rapid rise of salinity is observed in the Black Sea in recent years, with the largest positive trend (0.07 psμ per 10 years) detected in the pycnocline. We use long-term hydrological measurements for 1985–2019 to show that salinity of pycnocline has intense seasonal and interannual variability modulated by the mechanical and convective mixing. In the warm period of a year, shear turbulence driven by strong winds and intense geostrophic currents causes the penetration of warm waters into the lower density layers. This is accompanied by the rise in their salinity, the source of which is the deep saline waters situated below the halocline. This process is most intense in the areas of downwelling and intensifies in the autumn period, when thermal stratification is relatively weak. Another important reason is the entrainment of salty Mediterranean waters in the upper part of the Black Sea halocline, which is modulated by the deepening of the seasonal thermocline near the Bosphorus strait and mechanical mixing.The increase of salinity is compensated during cold winters, when convective mixing transports fresher water influenced by river discharge into lower density layers of the basin and causes a decrease in pycnocline salinity. This process is most intense in the center of the cyclonic gyres, where pycnocline is located closer to the surface and winter temperature reaches minimal values.Due to the long-term warming of the Black Sea, the process of freshening of deep layers now is observed only in rare cold years. At the same time, an intensification of wind speed, vorticity, and geostrophic circulation processes promote the blurring of the halocline and the rise of the salinity of the Black Sea upper layers. Such rise begins after 2007 in the upper part of Black Sea halocline (depth 50–100 m) and is traced down to 250 m by 2020.

Biomarker responses of Mediterranean mussels (Mytilus galloprovincialis, Lamarck 1819) regarding marine mucilage in the Sea of Marmara

It has been proposed that marine mucilage intensifies the biological effects of chemical pollutants and can increase their bioaccumulation in seafood. Indeed, in 2021, mucilage caused a major environmental disaster in the Sea of Marmara. Limited resources on the possible effects of marine mucilage on sustainable food security have increased the importance of this study. The aim of this study is to investigate the biochemical effects of mucilage in wild and cultured mussels, a bioindicator species collected from four different regions [Istanbul Strait (S1) and Canakkale Strait (S2), Bandirma (S3), Gelibolu (S4)] during the 2021 fishing season in the Sea of Marmara. The levels of reduced glutathione and lipid peroxidation, activities of antioxidant enzymes like glutathione reductase, glutathione-S-transferase, catalase, superoxide dismutase, activities of biomarker enzymes like alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase activities were determined. Our findings demonstrated that mucilage had an impact on cellular oxidative state and compromised the lipid cell membranes in the mantle tissues of Mediterranean mussels (Mytilus galloprovincialis, Lamarck 1819). It was found that there is a high positive relationship between seawater temperatures and bioparameters in S2 and S3 regions, except for GSH level. This study puts forward that in the presence of marine mucilage the biological responses and the state of health of mussels are negatively affected. Parameters which exhibit this kind of response may be used as biomarkers of exposure to marine mucilage in wild and culture mussel populations. Environmental disasters such as marine mucilage naturally affect food security by putting the sustainability of these species at risk.

Evaluation of biotoxins and toxic metal risks in mussels from the Sea of Marmara following marine mucilage

The mucilage phenomenon observed in the Sea of Marmara in 2021, has raised public concern about seafood safety. Mediterranean mussels serve as a vehicle in food chain, enabling the transfer of pollutants. Farmed and wild mussels were collected from 4 different stations throughout the fishing season. Biotoxins causing amnesic, paralytic, or diarrhetic shellfish poisonings (ASP, PSP, or DSP) were examined during monthly samplings. Potential health risks posed by cadmium, lead and arsenic were assessed. Health risks were evaluated considering 150 g/week mussel consumption, accounting for the different age groups of consumers (50, 60, 70 kg). Estimated Weekly Intake calculations of metals were determined to be lower than Provisional Tolerable Weekly Intake at all age groups throughout the sampling period in all stations. Target Hazard QuotientCd of mussels captured from Istanbul Strait was always determined <1, while it was equal to 1 for 50 kg individuals in Gelibolu samples. All THQAs were >1. Target carcinogenic Risk was evaluated for Pb and iAs, which were found to be negligible and acceptable, respectively. No biotoxins responsible for ASP, PSP, or DSP were detected. Hg levels were under detectable limits. Excluding Cd, the results did not reveal any risks associated with mussel consumption during mucilage.

Assessment of ambient particulate matter and trace gases in Istanbul: Insights from long-term and multi-monitoring stations

In this study, the long-term spatio-temporal variation, trends, and source increments of particulate matter (PM10 and PM2.5) and gaseous pollutants (SO2, NO, NO2, CO, O3) measured from 2015 to 2021 across 37 air quality monitoring stations in the European and Asian sides of Istanbul were investigated. The average PM10 concentration on the European side is higher than the Asian side. However, the average PM2.5 in both regions showed the same values. The results show that the industries near urban sites mainly affect PM10 concentrations in Istanbul. Ship emissions (from the Istanbul Strait) make the largest incremental contribution to SO2 and CO (211% and 139%, respectively) among other pollutants. PM10, PM2.5, SO2, and NO2 concentrations show significant (p < 0.01) negative temporal trends of 6.02%, 6.97%, 5.38%, and 3.28%, respectively, most notable in the winter season. However, the CO and O3 concentration trends are stable and increasing. According to the correlation coefficient (R) and the coefficient of divergence (COD) analysis, there is a heterogeneous distribution of pollutants at the intra-urban scale. PM2.5 concentrations are dominated by diverse pollution sources such as traffic, shipping and regional sources.

Empirical-singular-wavelet based machine learning models for sea level forecasting in the bosphorus strait: A performance analysis

Forecasting sea level is significant for sustainable water supply management, flood mitigation, shoreline maintenance, ecological sustainability, and economic advancement. In this study, a novel approach that incorporates decomposition methods with machine learning algorithms is presented. The objective is to enhance the accuracy of sea level predictions by tackling the challenges associated with sea level modelling, which arise from its complex characteristics and influence of various factors. This study introduced predictive frameworks incorporating Wavelet Decomposition (WD), Singular Spectrum Analysis (SSA), Empirical Mode Decomposition (EMD) with XGBoost (XGB), Decision Trees (DT), k-Nearest Neighbors (KNN), and Support Vector Machines (SVM). The study conducted predictions for time spans of 1, 7, and 30 days, evaluating the accuracy of the model's predictions using performance metrics. For the first day prediction, the XGB model achieved highest NSE value of 0.86, whereas the hybrid model (SSA-XGB) attained NSE value of 0.99. The hybrid model (EMD-XGB) produced remarkable results, attaining NSE value of 0.70 for the 7 day prediction time horizon. Additionally, the hybrid models (EMD-XGB and EMD-KNN) remarkably achieved NSE values exceeding 0.60 for 30-day time horizon. The results demonstrate that the hybrid models accurately predict daily sea levels with a lead time of up to 7 days. Additionally, the hybrid models demonstrated satisfactory prediction performance for time spans of up to 30 days. The hybrid models presented enhancements in both prediction accuracy and extended lead time predictions.

Contamination acts as a genotype-dependent barrier to gene flow, causing genetic erosion and fine-grained population subdivision in Mussels from the Strait of Istanbul.

This study provides evidence of fine-grained genetic structuring in Mediterranean mussels (Mytilus galloprovincialis) from the Strait of Istanbul, caused by barriers to gene flow via contaminant-mediated selection. In this study, mitochondrial D-loop sequences were analyzed in mussels from 8 localities, all less than 30 kilometers apart, with differing contaminant loads. The results were: 1) Intra-population genetic differentiation (ΦST) between sites with high and low contaminant loads was high (up to 0.459), even at distances of only a few kilometers. 2) Genetic diversity was negatively correlated with the contaminant load ("genetic erosion"). 3) There was evidence of selection, based on haplotype frequencies and neutrality tests (Tajima's D), with purifying selection at the most contaminated site and balancing selection at the least contaminated. 4) Genetic distance was not correlated with geographic distance (no isolation-by-distance), but was correlated with contaminant load at each site. 5) Population dendrograms and Bayesian estimators of migration indicated that gene flow between sites was affected by contamination. For the dendrograms of the sampling sites, the clades clustered according to contaminant load more than geographic distance. Overall, these results suggest that 1) contamination may serve as a genotype-dependent dispersal barrier (i.e., contamination may not affect total number of migrants, just the relative proportions of the haplotypes in the established immigrants), leading strong population differentiation over short distances, and 2) genetic erosion may occur by a combination of selection and altered patterns of haplotype-specific gene flow. These effects may be more pronounced in the Strait of Istanbul than in other locations because of the riverine nature and strong, uni-directional current of the strait.

Evaluation of Illegal, Unreported and Unregulated (IUU) Trawl Infringements Committed by Turkish Fishing Vessels

This study analyses a highly damaging and prevalent fishing practice of trawl infringements, which is one of the crucial components of IUU fishing in Turkish waters. The raw data gathered from the Turkish Coast Guard Command (TURCG), covered 2012 – 2014 period. Data covered a total of 1040 trawl infringements, with considerable differences in trawling violations among the seas surrounding Türkiye; the Black Sea, the Sea of Marmara, the Aegean Sea, and the Mediterranean Sea. With respect to trawling infringements, the Sea of Marmara (37%) and Istanbul Strait (15%) were the hot points. The most common infringement type was trawling in a closed area (43%) and when combined with the rate of infringements on trawling during the closed season (10%), these violations accounted for 53% of spatio-temporal infringements. Regarding illegal trawling by vessel type, trawl vessels had a 44% share and non-trawlers had a share of 56%, of which included infringements by other type of fishing vessels (46%) and non-fishing vessels (10%). It was also found that infringement by vessels smaller than 12 meters in length had a share of 46%. These vessels (known as "şebeke" in Turkish), trawl illegally using small types of nets and gears in coastal waters without giving any obvious indication of fishing activity. The results of this study will be useful to policy-makers, practitioners and scientists to successfully combat trawling infringements by providing information on distribution, intensity and methods of trawl violations.

Does Sea Level Change in The Strait of Istanbul, Türkiye?

Bosphorus is a narrow water passage connecting the Marmara Sea and the Black Sea through a sea level balance current flow. In this study, change points in mean and in variance and trend analysis are performed to reveal whether sea level is changing or not. Moreover, the simple linear regression is calculated to explain the relationships among sea level data in the three stations located in the Black Sea, the Marmara Sea and Bosphorus. The Turkish National Sea Level Monitoring System (TUDES) measures sea water level at each 15-minute periods in three stations in order to minimize the effect of turbulence. The sea level in the coastal area of Istanbul city is most populous region with its highly economic importance. The most important reason for this is the serious decrease in the amount of water discharged into the Black Sea due to dams and excessive water usage. The three sea level stations have no change points on the average of the whole data. The change points in variance are depicted especially in gap data years and especially around year 2018. While the difference in the sea level of the Istanbul and Sile stations contain seasonality, the difference between the other stations has a sinusoidal component. While this study lights on understanding the sea level characteristics of the Bosphorus, it also emphasizes the importance of accuracy, completeness and long-term measurement data requirement.

Сommunities of macrozoobenthos on soft sediments in the coastal areas of Peter the Great Bay near Vladivostok (Japan Sea) and their ecological status

At least 16 communities of macrozoobenthos are determined by modern statistical methods on soft sediments in the coastal areas with the depth of ≥ 5 m of Peter the Great Bay at Vladivostok surveyed in 2001–2019. They were: I. Scoletoma spp. + Sigambra bassi; II. Scoletoma spp. + Ophiura sarsii; III. Philine orientalis + Macoma sp.; IV. Aphelochaeta pacifica; V. A. pacifica + Capitella capitata; VI. O. sarsii + Macoma scarlatoi; VII. O. sarsii + Scoletoma spp. + Scoloplos armiger + Ennucula tenuis; VIII. Phoronopsis harmeri; IX. Maldane sarsi; X. A. pacifica + Dipolydora cardalia; XI. Scoletoma spp.; XII. Praxillella gracilis + Pelonaia corrugata, XIII O. sarsii + Acila insignis, XIV Scoletoma spp. + O. sarsii + M. sarsi; XV. Scoletoma spp. + M. scarlatoi, and XVI. A. pacifica. Their differentiation was determined by such environmental imperatives as the level of chemical pollution, eutrophication, and impact of terrigenous water discharge. By biotic indices (AMBI, M-AMBI, TPFbio), the most damaged and environmentally disturbed communities were IV, V, and XVI inhabited the Golden Horn Bay and Diomid Inlet. The communities of the East Bosphorus Strait (III, VI) have higher ecological status that increases even more in the Amur and Ussuri Bays (communities I, II, VII, XII, XIII, XV, XIV), except of the northern tips of both bays (IX, XI) and the eastern part of the Amur Bay (VIII, X). With such bioindicative approach, ecological status of the communities is described more concisely and visually than with indices of species richness, diversity, or W-statistics.

A proposed emergency response site selection for preventing pollution and collision effects using neutrosophic evaluation based on distance from average solution method and a numerical application in the Strait of Canakkale (Dardanelles)

The Turkish Straits Sea Area, encompassing the Sea of Marmara, the Strait of Canakkale, and the Strait of Istanbul, presents exceptional challenges due to its constricting and winding shape, making it one of the world's most difficult, busy, and hazardous waterways. The surge in marine traffic density in this vital waterway has raised concerns about collision risks. This study addresses two main problems: evaluating the adequacy of current Search and Rescue station locations for swift emergency response and identifying potential improved locations, if necessary. The research adopts a novel approach by utilizing neutrosophic data sets, a recently developed statistical method suitable for complex or indeterminate environments. This contributes to the advancement of alternative and contemporary techniques that enhance optimized decision-making. Notably, this study is the first to focus on the location and prioritization of emergency response points in the Çanakkale region, offering unique insights and original contributions to the field.

Microplastic concentration in the sediment of the Istanbul Strait (the Sea of Marmara, Türkiye)

Microplastic concentration in the sediment of the Istanbul Strait (the Sea of Marmara, Türkiye)

ОСОБЛИВОСТІ КЕРУВАННЯ СУДНОМ ПРИ ПЛАВАННІ В ПОРТОВИХ ВОДАХ У КОНТЕКСТІ ПІДГОТОВКИ МОРЯКІВ ТА ПЕРЕВІРКИ КОМПЕТЕНТНОСТІ

Establishment of the appropriate communication with the pilot, exchange of all the necessary information for the safe passage of the vessel, awareness by all responsible parties of their duties and the correspondence of their competency to the positions held, as well as knowledge and understanding, among other aspects, of the elements of bridge resource management theory, not only do not lose but even acquire greater relevance today. This fact is confirmed not only in practice but is also reflected in the relevant statistical materials. This partially appears in the following: despite the recommendations of the International Maritime Organization (IMO), other sources and the requirements of the relevant regulatory documents, many ship captains put too much trust in pilots when maneuvering the ship in port waters or channels. This paper examines the issue of sailing in port and inland waters from the perspective of the human factor's influence when using pilot services. The effectiveness of training for seafarers in the first approach has been evaluated with the aim of increasing the level of navigational safety and promoting responsibility awareness for all parties involved with regard to their duties, as well as assessment of their competency. In accordance with the obtained results, only 9.7% of seafarers out of the total number of participants were able to complete the set task of exiting the port water area in the Bay of Haydarpaşa (Istanbul, Turkey) and the Bosporus Strait in a safe and successful way on the first attempt and without pilot’s and/or tugs’ assistance. At the same time, this task did not cause difficulties for the respondents who undergo regular training in their companies and increase their level of competence. The experiment was conducted using a navigational simulator by means of simulation modelling methods. Keywords: ship handling, pilotage, certification and training, competence assessment.

Risky Maritime Encounter Patterns via Clustering

The volume of maritime traffic is increasing with the growing global trade demand. The effect of volume growth is especially observed in narrow and congested waterways as an increase in the ship-ship encounters, which can have severe consequences such as collision. This study aims to analyze and validate the patterns of risky encounters and provide a framework for the visualization of model variables to explore patterns. Ship–ship interaction database is developed from the AIS messages, and interactions are analyzed via unsupervised learning algorithms to determine risky encounters using ship domain violation. K-means clustering-based novel methodology is developed to explore patterns among encounters. The methodology is applied to a long-term dataset from the Strait of Istanbul. Findings of the study support that ship length and ship speed can be used as indicators to understand the patterns in risky encounters. Furthermore, results show that site-specific risk thresholds for ship–ship encounters can be determined with additional expert judgment. The mid-clusters indicate that the ship domain violation is a grey zone, which should be treated carefully rather than a bold line. The developed approach can be integrated to narrow and congested waterways as an additional safety measure for maritime authorities to use as a decision support tool.

Predicting the risky encounters without distance knowledge between the ships via machine learning algorithms

As the maritime traffic is getting denser, the number of encounters is increasing. The aim of this study is to develop a prediction model to classify encounters as risky or non-risky when two ships encounter in a certain buffer zone. A novel methodology is proposed to integrate three-dimensional clustering in the algorithm training process. K-means clustering, and ensemble machine learning algorithms-based prediction framework is developed to overcome class imbalance. The methodology is tested in the Strait of Istanbul (SOI) and parameters are generated from a long-term AIS dataset. Framework is validated via cross validation techniques. Precision, Recall, Accuracy and ROC-AUC Score are used as measures to evaluate models. Benchmark models are generated, and the most advanced model successfully predicts each 4 out of 5 risky encounters without the knowledge of distance between two ships. Eliminating distance from decision factors provides an action period before risky encounters. Therefore, proposed framework can be a guide for autonomous vessels for safe navigation and maritime authorities to improve maritime safety.

Evaluation of Istanbul Strait (Bosphorus) passage simulations in terms of CO2 emissions

It is crucial to reduce CO2 emissions due to marine transportation, which has a direct effect on air pollution in channels such as the Istanbul Strait (Bosphorus), which has a high human population density in the vicinity. In this study, it is tried to evaluate whether it is possible to reduce CO2 emissions during the passage of the Bosphorus. For this purpose, a mathematical model including three different control systems, called MPC, PD, and PD-Fuzzy controllers, is created to evaluate the controller effect on CO2 emissions during the passage. Each control system is selected separately from the mathematical model and the Bosphorus passages are simulated. As a result of these simulations, the velocity of the ship, the route to be followed by the ship, and the change of the ship's rudder angle throughout the passage are obtained using each control system. In these simulations, it is assumed that there are no external forces, such as wind and current. The obtained results from the simulations are accepted as a reference and an evaluation is made in terms of CO2 emissions by including the number of commercial ships passing through the Bosphorus between 2006 and 2019. The calculated annual CO2 emissions that may occur in the Bosphorus passage with the various control systems are compared. The CO2 emissions increases approximately 1.86% depending on the selection of the control system for the determined ship for the Bosphorus passage simulations. As a result, it is emphasized that a more effective control system for reducing CO2 emissions in narrow channel passages such as the Bosphorus can exist.