Search Results (978)

An empirical ridge statistic that correlates weekly level ice thickness with keel depth and weekly number of ridges was investigated using upward looking sonars (ULS) data from 2006 to 2020 in the Fram Strait. The applied methodology was similar to the previous studies for the Beaufort Sea. The data were divided into weekly segments. For each of them, level ice thickness ($h_i$), the number of ridges ($N$) and the average ($⟨h_k⟩$) and deepest ($h_{k\_deep}$) keel depth were calculated based on the Rayleigh criterion with a threshold of 2.5 m and a minimum keel draft of 5 m. The broader idea was to compare regions with different ice regimes, in order to see how the ridge statistics change and how well the model can handle these differences. In this paper, we compare the Beaufort Sea and the Fram Strait. Both have a positive correlation between level ice thickness and keel depth. Linear regressions $⟨h_k⟩={5.91+ 0.60h}_i$ and $h_{k\_deep}=8.67{+ 5.91h}_i$ with Pearson correlation coefficients $r=0.48$ and $r=0.45$, respectively, are established in this study, which are both lower than the Beaufort Sea results. Full article

Q355 carbon steel was exposed for 0.5 and 1 year in Pingtan Strait to examine how surface-wetness changes affect early rust-layer evolution and localized corrosion. Environmental monitoring, corrosion-rate measurements, rust-phase analysis, and electrochemical characterization were combined to characterize corrosion in this humid, salt-laden marine atmosphere. The exposure regime shifted from sustained wetness during the first half-year to frequent wet–dry cycling during the second. Although the average corrosion rate remained nearly unchanged, localized corrosion intensified and adjacent pits became interconnected. This change was closely associated with the evolution of the rust-phase assemblage and its spatial distribution. After 0.5 years, β-FeOOH was dominant, consistent with a long time of wetness (TOW) and Cl⁻ enrichment in surface electrolyte films, and pits remained largely isolated. After 1 year, Fe₃O₄ increased substantially and became the dominant phase, possibly because frequent wet–dry cycling altered oxygen transport within the rust and repeatedly produced locally oxygen-deficient conditions. Fe₃O₄ enrichment promoted continued pit deepening, followed by pit expansion and coalescence. Meanwhile, local α-FeOOH enrichment developed in relatively oxygen-rich regions near the rust surface and inhibited lateral pit propagation. Thus, shifts in the wetting regime of the humid, salt-rich Pingtan atmosphere markedly regulate localized corrosion of Q355 steel by controlling rust-phase evolution and spatial distribution. Full article

Synthetic Aperture Radar (SAR) enables high-resolution sea-surface wind speed retrieval. However, the enhanced spatial resolution of SAR imagery introduces substantial challenges, from small-scale contamination sources that significantly degrade retrieval accuracy. Particularly in coastal regions, non-wind-related backscatter signals, such as ships and oil slicks, can severely bias wind speed estimates at sub-kilometer scales. In this study, the first-order moment (average, m₁) and second-order moment (variance, m₂) are computed from the normalized radar cross-section (NRCS) within sub-images of Sentinel-1 SAR data acquired in Interferometric Wide (IW) mode. Analysis reveals that clean-sea-surface signals in both VV and VH polarizations cluster around an approximately linear empirical trend, m₂ = 2m₁ + b, in the m₁-m₂ statistical feature space, whereas the examined contamination types deviate from this trend and occupy separable regions. Based on this characteristic, a quality-control framework is proposed for the systematic separation of clean sea surface from image noise (border noise and inter-swath stripe noise) and non-ocean targets (land contamination, bright targets, and dark spots). Validation using independent SAR data from the Taiwan Strait was conducted separately for native 10 m and height-adjusted 3 m buoy observations. For the native 10 m observations, the RMSE and MBE were essentially unchanged at 1.5 m/s and −0.3 m/s, respectively. For the height-adjusted nearshore observations, the RMSE decreased from 3.2 m/s to 2.1 m/s and the MBE changed from −1.5 m/s to −1.1 m/s. Full article

In the Fram Strait, Atlantic Water (AW) flows northward through the eastern part of the strait, while Polar Surface Water (PSW) moves southward from the Arctic Ocean through its western part. Mixing of these water masses produces mixed AW (mAW). As these water masses move, significant changes occur in salinity, temperature, density, and nutrient concentrations, restructuring the phytoplankton community. Based on surveys conducted in August 2021 during the 84th cruise of the R/V Akademik Mstislav Keldysh, the dominant species were identified for each water mass. Among the key species (10 diatoms, 11 dinoflagellates, two coccolithophores, and one species each of chrysophyte, haptophyte, and ciliates), three ecological assemblages were distinguished: a cold-water PSW indicator complex (Porosira glacialis and Rhizosolenia hebetata f. hebetata among diatoms, the dinoflagellate Protoperidinium islandicum, and the ciliate Mesodinium rubrum); a warm-water AW complex (Navicula planamembranacea, Stephanopyxis turris, Rhizosolenia styliformis, the dinoflagellates Protoperidinium depressum and Tripos spp., and the coccolithophore Coccolithus pelagicus); and an mAW complex (the diatom Thalassiosira rotula, the coccolithophore Gephyrocapsa huxleyi, the haptophyte Phaeocystis pouchetii, and the chrysophyte Monochrysis sp.). Moving from south to north into the Fram Strait and from east to west towards the Greenland shelf, warm-water Atlantic indicator species were first replaced by mAW species, and then by cold-water species in the PSW. Maximum phytoplankton biomasses (up to 670.8 mg/m³) were observed in the marginal ice zone, driven by the intensive growth of large diatoms at depths within the euphotic zone where AW and PSW interact. If this interaction depth lies outside the euphotic zone, the phytoplankton biomass is determined by ciliates. In open water, large dinoflagellates contributed most to the biomass, indicating the decisive role of mixoplankton (mixotrophic plankton) in summer at high Arctic latitudes. Full article

The Luzon Strait is a critical generation site for global internal tides. Their generation and propagation are significantly modulated by background currents, including the Kuroshio Current and mesoscale eddies. This study investigates nonlinear effects of these background currents on low-mode (modes 1–3) internal tides using a high-resolution numerical simulation. We apply the Taylor–Goldstein equation considering the Earth’s rotation and background currents to perform modal decomposition, and utilize a nonlinear internal tidal energy equation to quantify three crucial energy pathways: inter-modal energy conversion, nonlinear energy exchange with background currents, and nonlinear advection effects. Results demonstrate that while stationary mode-1 internal tides dominate in the generation region of the Luzon Strait, non-stationary energy increases significantly in the western and eastern propagation regions, driven largely by seasonal variability of the Kuroshio Current. Inter-modal energy conversion follows a cascade from lower to higher modes, with conversion efficiency increasing with mode number. Nonlinear exchanges between background currents and internal tides are one order of magnitude smaller than inter-modal conversions but exhibit a bidirectional transfer, where advection redistributes internal tidal energy within the eddy structures. This study provides a quantitative framework for understanding multiscale energy pathways of internal tides under complex ocean dynamics. Full article

Underground gas storage (UGS) facilities serve to balance natural gas networks within a given area. The nature of natural gas network balancing is twofold: long-term (seasonal) during periods of significant gas withdrawal (the cold half-year) and short-term (daily) during periods of peak natural gas demand throughout the day. The first type of balancing has been a standard characteristic for many years, covering increased demand during the winter season. In contrast, the importance of daily balancing is growing alongside the ongoing energy transition, where natural gas-based power generation sources flexibly replace renewable energy sources that are dependent on the time of day or weather conditions. The necessity for increased balancing of energy systems makes them more sensitive to crisis situations. This article presents the key role of UGS as a fundamental resilience factor for European energy systems, particularly in the face of energy crises triggered by geopolitical instability. Conflicts are redefining the role of UGS as a pillar of energy security. This study analyzes how strategic gas reserves mitigate the effects of sudden supply disruptions and price shocks caused by geopolitical factors. It describes impact scenarios of two conflicts: Russia’s invasion on Ukraine and the conflict in the Persian Gulf leading to the closure of the Strait of Hormuz. While UGS is essential for the short-term management of natural gas supply flows, its long-term value lies in providing a “strategic buffer” that allows energy systems to adapt to unforeseen geopolitical conflicts. Integrated storage management is indispensable for maintaining the operational integrity of the European transmission and energy system during periods of heightened instability. The paper also identifies necessary directions for the development of UGS systems. Between 2016 and Q1 2026, the share of eastern gas imports declined from over 40% to 5.2%, while LNG increased to 41.7% of total inflows, confirming the strategic importance of underground gas storage in maintaining energy system resilience. Full article

In 2024, an accident involving two tankers in the Kerch Strait resulted in the release of approximately 2400 tons of fuel oil into the Black Sea, causing significant contamination of seawater and the coastal zone. This study presents the first microbiological and molecular–ecological assessment of prokaryotic community composition and hydrocarbon-oxidizing bacteria (HOB) in coastal seawater and sand near Anapa (Russian Federation) following the spill. The taxonomic composition of nine samples was analyzed using high-throughput sequencing of 16S rRNA genes (V3–V4 regions), identifying Bacteria as the dominant domain (85.3–99.8%). In seawater samples, bacteria of the phyla Pseudomonadota, Cyanobacteriota, and Bacteroidota and archaea of the phyla Thermoplasmatota and Crenarchaeota predominated. Eighteen aerobic bacterial strains, including members of the genera Shewanella, Pseudoalteromonas, Halopseudomonas, Marinomonas, Pseudomonas, Vibrio, Alcanivorax, Ectopseudomonas, Nitratireductor, and Echinicola, were isolated from the zone of fuel oil spill. Several isolates demonstrated heavy oil degradation and biosurfactant production. Screening of collection strains isolated from other habitats revealed that Rhodococcus erythropolis TG65 and Marinobacter lutaoensis Pd1 and Pd2 degraded 92–94% of fuel oil n-alkanes. Elevated dissolved iron concentrations in the seawater indicate the possibility of a metabolic coupling between hydrocarbon oxidation and microbial iron reduction, mediated by indigenous Shewanella and Pseudomonas species. These findings indicate that indigenous HOB may contribute to the natural attenuation of aliphatic hydrocarbons in fuel oil. Full article

Background: Germline pathogenic variants in BRCA1/2 increase breast and ovarian cancer risk, but their prevalence in Aboriginal and Torres Strait Islander (herein referred to as Aboriginal) families has never been studied. Consequently, their contribution to breast cancer in this population is unknown. Methods: This retrospective cohort study included 259 Aboriginal women and 789 age- and remoteness-matched non-Aboriginal women diagnosed with breast cancer (2001–2016). We assessed family history, genetic service referral and testing rates, and pathogenic variant rates in the context of testing access. Results: Family history data were available for more Aboriginal than non-Aboriginal cases (46% vs. 34%, p < 0.001), with no difference in reported first-degree relatives with breast (22.5% vs. 22.4%, p = 0.98) or ovarian cancer (4.2% vs. 2.2%, p = 0.29). Similar proportions were referred to genetic services for testing eligibility (5.4% vs. 7.2%, p = 0.392). Of those referred, similar proportions were offered testing (86% vs. 81%, p = 0.66). Across the full cohort, BRCA1/2 pathogenic variants were detected in 0.77% of Aboriginal versus 2.4% of non-Aboriginal women (p = 0.127); any pathogenic gene variant was detected in 0.77% versus 3.0% (p = 0.039). Conclusions: Pathogenic genetic variants were detected less frequently in Aboriginal women, although, in keeping with international clinical practice, most women diagnosed with breast cancer were not tested. Given that only a small proportion of the cohort underwent germline testing, this study cannot distinguish whether the lower detection rate reflects a genuinely lower population level prevalence of pathogenic variants or differences in historical referral, selection, and testing practices. These findings are hypothesis-generating and require validation in larger Australian Aboriginal studies including unselected populations with whole-population testing data. Full article

Short-horizon collision–risk warning can use instantaneous assessment, forecast-then-assess, or direct prediction from encounter histories. We evaluate the third route with the Anticipatory TRAffic-context Collision–risk Transformer (ATRACT), which estimates the maximum near-future fuzzy Collision Risk Index (CRI) directly from own-ship kinematic and collision-geometry histories without trajectory rollout. Experiments use ten days of Automatic Identification System (AIS) data from the Danish straits, comprising 1.63 million decision windows. Using a vessel-day-track partition and five random initializations, ATRACT attains an area under the receiver operating characteristic curve (ROC-AUC) of $0.814\pm 0.003$, compared with $0.808\pm 0.006$ for the evaluated forecast-then-CRI baseline (VCRF) and 0.729 for instantaneous CRI. Thresholds fixed at a nominal 5% false-alarm rate (FAR) on disjoint calibration tracks yield test FARs of 4.98% and 5.38% for ATRACT and VCRF. Although seed-0 track-bootstrap intervals include zero at every evaluated offset, ATRACT shows 4.4–10.8 percentage points higher mean pre-onset detection across 0.5–4 min over five random initializations; VCRF detects more individual high-risk windows at this operating point. Four direct-risk encoders achieve a narrow ROC-AUC range of 0.813–0.819. These results support direct temporal interaction modeling as a viable route while limiting conclusions to the evaluated forecast-first implementations. Full article

Anthropogenic greenhouse gases (GHGs) and emissions from maritime transport represent a significant challenge for atmospheric monitoring and control. The Istanbul Strait, characterized by its narrow, winding geography and high traffic density, presents a unique chokepoint where these emissions directly impact local air quality. This study proposes a gas-focused integrated framework that combines Sentinel-5 Precursor (Sentinel-5P) TROPOspheric Monitoring Instrument (TROPOMI) satellite observations with Automatic Identification System (AIS) data to analyze atmospheric trace pollutant time series in the Istanbul Strait during 2025. A bottom-up emission methodology based on the IMO 4th GHG Study was employed, yielding annual gaseous pollutant totals of 213,678 tons of carbon dioxide (CO₂), 5970 tons of nitrogen oxides (NO_x), and 686 tons of sulfur oxides (SO_x). Time-series and cross-correlation analyses demonstrated a quantifiable relationship between AIS-derived NO_x estimates and TROPOMI NO₂ tropospheric column densities (r = 0.76, p < 0.05, n = 12), validating the use of satellite sensors for marine atmospheric monitoring. A decision support system (DSS) proof of concept (PoC) was developed to evaluate emission control scenarios through speed optimization. The results indicate that implementing a 10% speed reduction strategy could reduce CO₂ emissions by 18% (38,462 tons) and generate net economic savings of EUR 3.07 million under the European Union Emissions Trading System (EU ETS) carbon pricing framework. Furthermore, a scenario with a 20% speed reduction resulted in a 35% decrease in CO₂ emissions. The findings underscore the potential of integrating satellite-based gas remote sensing with AIS data, thereby facilitating real-time atmospheric monitoring and strengthening emission control policy enforcement in maritime chokepoints. Full article

Fatigue assessment of floating offshore wind turbines (FOWTs) remains challenging because fatigue-sensitive regions may occur outside conventional predefined hotspots. This study applies a previously numerically verified full-field fatigue-screening workflow combining Unit Load Response, submodeling, and Virtual Test Rig concepts to the TaidaFloat semi-submersible FOWT under Taiwan Strait environmental conditions. Reconstructed nodal stress histories are used to map hull fatigue and evaluate occurrence-weighted contributions from 182 environmental bins, including operational and typhoon conditions. The results identify fatigue-sensitive regions not only at conventional column–bracing and column–pontoon connections but also in the upper main column and along the turbine–hull load path. Upper column fatigue is mainly associated with turbine-induced bending, whereas lower column and waterline-adjacent regions are more sensitive to wave-induced global hull bending. Frequently occurring near-rated operational conditions dominate the occurrence-weighted hull fatigue contribution, while selected typhoon conditions produce high short-term damage but limited long-term contributions within the four-year dataset. Approximately 94.6% of hull fatigue damage is captured by 28% of the bins, and a common hull–mooring set captures 97.0% of both contributions using 62% of the bins. These findings support hotspot screening and environmental-bin prioritization rather than detailed or certification-level fatigue life prediction. Full article

Safe navigation in coastal waters remains a persistent challenge for conventional grid-based path planning methods, which prioritize shortest-distance optimization while neglecting spatial risk distribution and kinematic trackability. This study proposes a local path planning framework that integrates an integral image-based risk field with kinematic constraints for small vessel navigation in high-resolution coastal environments. The proposed method evaluates local obstacle density through an area-based spatial risk model and employs an integral image structure to reduce risk computation complexity from O(W²) to O(1). A 16-direction node expansion strategy incorporating kinematic filtering and cubic B-spline smoothing was applied to improve maneuvering feasibility and trajectory continuity. Simulation results across two topologically distinct coastal environments, Mokpo–Sinan and Myeongnyang Strait, demonstrated that the proposed framework increased the minimum clearance distance from 20 m to 238.32 m and the average clearance distance from 884.2 m to 1038.3 m relative to the conventional A* algorithm, and consistently outperformed a static buffer-based baseline. The 16-direction search reduced the maximum course change angle by up to 39% and the average course change angle by up to 55% relative to the 8-direction configuration across both environments while maintaining practical computational efficiency. Kinematic feasibility was further verified through curvature-based analysis of the final smoothed trajectories, confirming that the minimum turning radius consistently exceeded the vessel’s theoretical minimum turning radius across all tested configurations. The results demonstrate that the proposed framework can generate risk-aware and kinematically feasible navigation routes using coastline-based occupancy information alone, suggesting potential applicability to coastal autonomous navigation in environments with limited bathymetric data. Full article

To the best of our knowledge, this is the first study that centres Indigenous queer (henceforth, Indigiqueer) and Indigenous older people and Elders’ voices to explore the everyday tensions between protecting Indigenous cultural protocols against colonial incursions and the challenges presented by shifts in essentialist understandings of gender in the country now called Australia. There is to date very little written that address this topic, although there are two seminal works that investigate the matters more broadly, one by leading Aboriginal scholar Professor Bronwyn Carlson, and another by Noongar Wardandi scholar Professor Braden Hil. Our study uses a set of vignettes based on two interviews with Indigiqueer people and a yarning circle with Indigenous older people and Elders. The interviews and yarning circle are structured as a discussion between community members to provide some preliminary analysis about contemporary dynamic intergenerational debates within Indigenous communities in which competing understandings of culture, gender, safety, and responsibility coexist. For participants, intergenerationality is seen as central to both harm and healing, feelings of belonging and ostracism and ultimately to current and future Indigenous and Indigiqueer survivance and thrivance. Indigenous older people and Elders demonstrate an openness to different sexualities and an acceptance of sexuality-diverse people but are hesitant to allow gender-diverse people to participate in gendered community activities such as playing the didgeridoo (yidaki). To the contrary, Indigenous queer (henceforth Indigiqueer) participants articulate their fears regarding safety, exclusion, care and social isolation emerging from exclusionist gendered binary protocols. Younger generations are seen by all participants as sites of potentiality, that in combination with the power of shared storytelling and mutually constructed understandings, enable a shift towards greater acceptance, openness, and visibility. The paper also reveals the ways in which Indigiqueer people navigate spatial, cultural and social differences between regional and urban spaces, that are seen as differentially accepting of either their Indigeneity or their gender and sexuality diversity. The study’s findings also demonstrate the importance of Indigiqueer-controlled spaces and culturally safe organisations, that are grounded in community-led practices of care, belonging, and self-determination. Full article

A high-resolution unstructured-grid ocean model was used to investigate the generation, propagation, and dissipation of M₂ internal tides in the Luzon Strait and northeastern South China Sea, with the aim of clarifying how energy evolves across contrasting topographic regimes. Wave decomposition, harmonic and modal analyses, energy-budget diagnostics, and along-path tracking were applied to quantify the spatial distribution and modal evolution of internal-tide energy. The results show that the Luzon Strait double-ridge system is the primary source region, contributing approximately 4.826 GW of barotropic-to-baroclinic energy conversion, with the Lanyu Ridge (3.080 GW) exhibiting stronger conversion than the Hengchun Ridge (1.643 GW). The generated low-mode internal tides radiate mainly westward into the northeastern South China Sea, with energy progressively attenuated over the deep basin and continental slope. Energy-budget analyses indicate that the ridge region dominates generation, the Luzon Trough mainly supports transmission, and the deep basin and slope are associated with enhanced dissipation and scattering. Along-path energetic diagnostics quantitatively reveal a sequential depletion of mode 1 internal-tide energy in the vicinities of steep topography and internal-tide steepening zones, concomitant with a marked augmentation of mode 2 energy and intensified cross-frequency energy transfer. Specifically, within the deep basin of the South China Sea, the fractional contribution of mode 1 energy declines from 78.3% to 73.8% as the internal tide propagates from the abyssal to the shallower shelf-slope region, whereas that of mode 2 increases correspondingly from 18.2% to 24.3%. Moreover, pronounced internal-tide steepening is observed in the deep basin, and the spectrally integrated cross-frequency transfer coefficient reaches 0.32 in this area, substantially exceeding that in other regions. These findings suggest that topographic scattering, modal redistribution, and nonlinear interactions contribute substantially to regional internal-tide dissipation. Full article

Static Acoustic Monitoring (SAM) using C-PODs, deep C-PODs, and F-PODs was conducted as part of the STRAITS project (Strategic Infrastructure for improved animal Tracking in European Seas), funded under the EU’s Horizon research and innovation programme, to investigate odontocete acoustic occurrence across four European straits: the North Channel, the Sound, the Strait of Gibraltar, and the Dardanelles Strait. The acoustic presence of dolphin species and harbour porpoises was modelled in relation to tidal cycle, moon phase, sea surface temperature (SST), diel period, season, and Sound Pressure Levels (SPLs), representing ambient underwater sound using a Generalised Additive Modelling (GAM) approach. Harbour porpoises were primarily detected in the Sound and the North Channel, while dolphin detections were higher in the Strait of Gibraltar and the Dardanelles Strait. There was a significant association with SPLs on both species across all locations where it was assessed. There was a significant effect of tidal cycle and SST on both species across all locations except the Dardanelles Strait. Temporal patterns were significant across species and study sites. This study presents the first multi-strait assessment of odontocete occurrence in key marine corridors, highlighting the relationship of environmental and temporal drivers, underwater noise, and odontocete occurrence, and providing insights for marine spatial planning and conservation management in highly trafficked regions. Full article