The Eforie Nord sector (between the southern pier of Agigea - Constanta port and the tourist port of Belona), is characterized, from a geomorphological point of view by the presence of high cliffs and narrow beaches. In the mentioned sector, a series of coastal protection works were carried out in several stages, respectively: between 1956 and 1960, 6 groins were placed to etend the perimeter beach; with the epansion of Constanța port, new coastal protection measures were imposed (1981-1986), determined by the erosion processes, made concrete by the eecution of permeable submerged longitudinal dikes in addition to the transversal ones. On long term, the measurements of shore morphological parameters highlighted that the southern sector of the Romanian Black Sea coast is subject to an erosion process, due to the action of both natural and anthropogenic factors, each generating effects with different intensity, depending on local conditions. Within the project “Protection and Rehabilitation of the Southern Part of the Romanian Black Sea Coast, Phase 1” in 2014-2015 period, in the mentioned sector, etended hydrographical works were carried out, including the rehabilitation of dikes, the construction of submerged dikes and beach nourishment. The monitoring of the shore behavior at regular intervals (annual/seasonal) which is essential for an adequate management of the coastal area, highlights both cyclical/seasonal morphological changes (rapid erosion as a result of storms in the cold season and the reconstruction of the beach during summer) and progressive/multiannual changes. The monitoring of morpho dynamic changes at shore level includes the positioning of the shoreline and beach profiles in 6 locations using GPS equipment (geodetic and GIS class). The resulting spatial data were processed and included in the SANDS management system that allows comparative analysis at different time scales. The maps representations were made in the ArcGIS 10.8 system. The data analysis revealed seasonal changes of the shore morphology, both in the longitudinal profile (shoreline) and transversally (beach profiles).

Coastal erosion poses a significant risk to the Romanian Black Sea coast, a region characterized by the interaction of natural geomorphological processes and anthropogenic pressures. The research focuses on developing a tool to quantify the cumulative impact of hydro-geo-morphological factors and to assess the vulnerability of the coastal zone to these influences. The approach involves adapting the Coastal Vulnerability Index (CVI)—previously applied in various methodologies—to the specific characteristics of this semi-enclosed basin, which included the exclusion of the tidal range variable due to the Black Sea’s negligible tidal amplitude. The selection of key variables, including coastal geology and geomorphology, shoreline change rates, coastal slope, sea level, and wave regime, was conducted with consideration for the specific characteristics of the Romanian coastal zone. By classifying these variables on a semi-quantitative scale and integrating them into a CVI, the study identifies and maps areas of high vulnerability. The analysis, based on a 1 × 1 km grid resolution, identified sectors of very high vulnerability in the northern Danube Delta unit, particularly along the coastlines of South Sulina–Câşla Vădanei, Sahalin, and Periboina-Edighiol-Vadu. These findings are validated through a comparison with long-term, multidecadal shoreline evolution data, confirming the model’s predictive accuracy. While the 1 × 1 km grid is effective for a macro-scale assessment, the study highlights the need for a finer resolution (e.g., 100 × 100 m) for detailed analysis in the southern region, due to localized geodynamic conditions and the significant influence of coastal infrastructure.

This study examines the hydro-sedimentological–radioecological controls governing the distribution of natural (K-40, Ra-226, Th-232) and anthropogenic (Cs-137) radionuclides in surface sediments of the western Black Sea shelf. Activity concentrations were determined by high-resolution gamma spectrometry, and radiological indices—including radium equivalent activity (Ra_eq), external hazard index (H_ex), and annual effective dose (AED)—were calculated to evaluate environmental safety. All indices remained well below internationally accepted thresholds, confirming the absence of radiological hazard in both coastal and offshore settings. Strong correlations between Ra-226 and Th-232 indicate dominant lithogenic control of natural radionuclides, whereas Cs-137 exhibits geochemical decoupling consistent with its behavior. A significant relationship between the fine-grained sediment fraction (<63 µm) and Cs-137 activity highlights the grain size effect, with offshore depositional zones acting as sediment-focusing areas where Cs-137 and excess Pb-210 co-accumulate under low-energy hydrodynamic conditions. Despite localized offshore enrichment, dose contribution analysis shows that natural radionuclides dominate the absorbed-dose budget, while Cs-137 contributes only marginally. Spatial predictive modeling using Artificial Neural Networks, validated under a Spatial Leave-One-Group-Out framework, yielded moderate generalization capacity (R² = 0.61 for Ra-226; R² = 0.41 for Cs-137), reflecting smoother spatial gradients of lithogenic radionuclides than heterogeneous radiocesium deposition. Furthermore, Machine Learning algorithms provided significant analytical value: a Random Forest (RF) model successfully classified environments (nearshore/shelf/depositional basin) based on distinct radionuclide signatures. At the same time, an optimized Artificial Neural Network (ANN-GA) enabled the nonlinear reconstruction of radiometric–granulometric patterns to identify local anomalies. The results show that radionuclide distributions are primarily structured by sediment provenance, grain size sorting, and hydrodynamic energy gradients rather than ongoing anthropogenic inputs.

This study examines cross-shore morphological variability in three beach profiles within the engineered coastal sector of Constanța, Romanian Black Sea, over the period 2022–2024. Annual GPS-based topographic surveys were conducted using high-precision equipment (GIS-grade and geodetic-class RTK receivers with real-time ROMPOS corrections) along fixed transects marked by permanent benchmarks. Morphological changes were evaluated relative to the 2015 post-beach nourishment profile, which served as the baseline for comparative analysis. To explore the influence of hydrodynamic conditions, the evolution of the beach profile was correlated with sea surface height (SSH) data from the Copernicus Marine Environment Monitoring Service (CMEMS), capturing seasonal and interannual sea level variability. Results show that the shoreline response closely follows SSH trends: lower SSH values were generally associated with stable or accreting profiles, while higher values, especially during storm events, triggered crest retreat, scarping, and upper beach erosion. Among the transects studied, CT1 showed the most significant erosion, whereas CT3 exhibited greater resilience due to the development of a berm. These findings highlight the value of integrating SSH variability and high-resolution GPS surveys to enhance coastal monitoring and inform adaptive shoreline management strategies in engineered environments. Keywords: Beach profiles, coastal morphology, sea level variability, GPS survey, Romanian Black Sea