Plastic pollution has been observed in many marine environments surrounding the Iberian Peninsula, from the surface water to deeper waters, yet studies on their pathways and accumulation areas are still limited. In this study, a global ocean reanalysis model was combined with a particle-tracking Lagrangian model to provide insights into the pathways and accumulation patterns of microplastics originating in southern Portuguese coastal waters (SW Iberian). The study investigates microplastics floating on the surface as well as submerged at different water depths. Model results suggest that the North Atlantic Gyre is the main pathway for microplastics in surface and subsurface waters, transporting the microplastics southwards and eastwards towards the Mediterranean Sea and the Canary Islands. Currents flowing out of the Mediterranean Sea act as the main pathway for microplastics in deep waters, transporting the microplastics along western Iberia. An average residence time of twenty days in the coastal waters suggests that microplastics do not accumulate close to their sources due to their relatively fast transport to adjacent ocean areas. Notably, a significant proportion of microplastics leave the model domain at all depths, implying that SW Iberia may act as a source of microplastics for the adjacent areas, including the Mediterranean Sea, Morocco, the Canary Islands, Western Iberia, and the Bay of Biscay.

Global climate change has induced a rise in sea surface temperature (SST), although this increase is not uniform across the world. Significant variations exist between coastal and offshore waters, particularly in regions affected by upwelling processes. This study focuses on the Canary Current Upwelling System (CCUS), stretching from Northwest Iberia to Northwest Africa. High-resolution remotely sensed SST data (0.05°) from the ODYSSEA Level 4 Sea Surface Temperature Reprocessed dataset were validated with in situ measurements and employed to establish a regional climatological baseline for 1982–2012. Subsequent years were compared to this baseline to construct SST anomaly maps, revealing SST changes since 2012. The study area was further divided into sub-regions for comparative analysis. Results indicate that SST consistently increased at a higher rate offshore compared to the adjacent nearshore regions. A reference dataset spanning 1951–1981 was used to gauge SST variability between the two baselines. SST exhibited a 0.59 °C increase from 1951–1981 to 1982–2012, with a slowing of SST trends beyond the 1982–2012 baseline. This research offers valuable insights into the climatological dynamics of the CCUS. These findings enhance our understanding of this critical coastal system’s climatology, laying the groundwork for future investigations into evolving climate patterns in coastal regions.

Simulating wave propagation is crucial for forecasting processes offshore and near the coast. Many operational wave models consider only atmospheric and wave forcing as boundary conditions. However, waves and currents are interdependent, and simulating their interaction is crucial for accurately representing wave propagation. This study examines the influences of the current velocity and water levels on waves on the southern coast of the Iberian Peninsula. These forcing elements were simulated by a 3D hydrodynamic model (MOHID) and included in the Simulating WAves Nearshore (SWAN) model. The standalone SWAN model was calibrated and validated by comparing results of significant wave height, mean wave direction, and peak period with in situ observations. Then, the effects of water levels and current velocities on wave propagation were assessed by forcing the SWAN model with water levels as well as current velocities extracted from different depths: the surface layer and depth-averaged velocities from the surface down to 10 m, 20 m, and the full water column. The results revealed that incorporating the current velocity and water levels from MOHID into the SWAN model reduced the root mean square error (RMSE) between 1.6% and 27.6%. The most accurate results were achieved with model runs that included both the current velocity from the surface layer and water levels. Opposing currents resulted in increases in wave height, whereas following currents resulted in decreases in wave height. This work presents novel results on the effects of hydrodynamics on wave propagation along the southern coast of the Iberian Peninsula, a region of key importance for the blue economy.

Submerged underwater cultural heritage (UCH) provides insight into past human behavior and history and thus the preservation of these artifacts at the site of discovery is crucial. However, marine environmental conditions such as physical, chemical, and biological processes directly impact the degradation of these underwater historical sites. Under the frame of the Horizon Europe project THETIDA (Technologies and methods for improved resilience and sustainable preservation of underwater and coastal cultural heritage to cope with climate change, natural hazards and environmental pollution), which runs between 2023 and 2026, the current work aims to demonstrate the suitability of process-based numerical models to (1) predict in real-time hazards threatening UCH sites associated with currents and sediment abrasion and (2) to estimate the risks associated with these oceanic conditions. This general approach is demonstrated for the Coast of Algarve (southern coast of Portugal), focusing specifically on the B-24 wreck. This WWII bomber airplane rests on the bottom of the coastal shelf at 20 m deep and approximately three kilometers offshore of Praia de Faro. The methodology couples a wave model (SWAN) to an existing operational hydrodynamic system SOMA powered by the MOHID model, which will provide inputs to run a non-cohesive sediment transport model. In-situ measurements and laboratory experiments will be used to determine deterioration rates that will provide insights into risk categorization and impacts on UCH sites. The final product will be a demonstrative operational ocean model for UCH management, assessment, and emergency response.Acknowledgement: This research has been funded by the European Union’s Horizon Europe research and innovation programme under THETIDA project (Grant Agreement No. 101095253) (Technologies and methods for improved resilience and sustainable preservation of underwater and coastal cultural heritage to cope with climate change, natural hazards and environmental pollution). The authors also acknowledge Fundação para a Ciência e Tecnologia (FCT), under the project LA/P/0069/2020 granted to the Associate Laboratory ARNET and UID/00350/2020 CIMA (https://doi.org/10.54499/UIDP/00350/2020).

Global climate change has induced a rise in sea surface temperature (SST), although this increase is not uniform across the world. Significant variations exist between coastal and offshore waters, particularly in regions affected by upwelling processes. This study focuses on the Canary Current Upwelling System (CCUS), stretching from Northwest Iberia to Northwest Africa. High-resolution remotely sensed SST data (0.05°) from the ODYSSEA Level 4 Sea Surface Temperature Reprocessed dataset were validated with in-situ measurements and employed to establish a regional climatological baseline for 1982 – 2012. Subsequent years were compared to this baseline to construct SST anomaly maps, revealing SST changes since 2012. The study area was further divided into sub-regions for comparative analysis. Results indicate that SST consistently increased at a higher rate offshore compared to the adjacent nearshore regions. A reference dataset spanning 1951 – 1981 was used to gauge SST variability between the two baselines. SST exhibited a 0.59°C increase from 1951 – 1981 to 1982 – 2012, with a slowing of SST trends beyond the 1982 – 2012 baseline. This research offers valuable insights into the climatological dynamics of the CCUS. These findings enhance our understanding of this critical coastal system's climatology, laying the groundwork for future investigations into evolving climate patterns in coastal regions.

Underwater cultural heritage (UCH) sites provide insight into past human behavior and history and thus their preservation is crucial. Within the scope of THETIDA, a Horizon Europe project dedicated to developing technologies and methods to protect coastal and underwater cultural heritage, this work aims to predict the physical processes that can put UCH at risk. This risk assessment is applied to a specific site in the Algarve, Portugal where a WWII U.S. B24 bomber plane crashed approximately 3 km offshore Praia de Faro. The plane now sits 21 m deep on the coastal shelf, which consists mainly of sand. The site is exposed to dominant, more energetic waves coming from W-SW and sheltered from less energetic E-SE waves. The mean significant wave height is 0.9 m, but it can rise to above 3 m with the occurrence of storms. As the site is located in the open ocean, a highly energetic environment, the site is subject to risks caused by wave-induced currents and sediment transport. To analyze and predict these risks in real time a numerical framework integrating three operational process-based models was developed. The numerical system is composed of: 1) the wave model SWAN, 2) the hydrodynamic model MOHID, and 3) the sediment transport model MOHID sediment. The operational wave model uses bathymetric data from EMODNET and is forced with wind conditions from the Skiron Atmospheric Modeling and Weather Forecasting Group in Athens and wave conditions at the boundary from the Copernicus Marine Environmental Monitoring Service (CMEMS). The model was calibrated by testing various formulas for the physical parameters attributed to wave propagation. A statistical analysis was completed to determine the best physics formulas to use for the model by comparing the results of each calibration setting with in-situ buoy measurements. SWAN was then two-way coupled to the hydrodynamic modeling system SOMA (Algarve Operational Modeling and Monitoring System), which is powered by MOHID. The coupling mechanism forces the wave model with velocities and water level output from SOMA and forces SOMA with wave results from SWAN. Preliminary results of the coupling revealed that the impact of current velocity and water levels on wave propagation in the study area is negligible in deeper areas, where the observations used for model validation lie. Further investigations are been conducted to analyze the effects of the two-way coupling in nearshore areas such as the location of the B24. The wave-hydrodynamic coupled system is now being used to develop a non-cohesive sediment transport model, which will be used to evaluate in real-time risks on UCH. This forecasting system will be included in the decision support system of the THETIDA platform.