Search Results (304)

Wind power has gained attention as a vital renewable energy source capable of reducing emissions and serving as an effective alternative to fossil fuels. Floating wind farms could significantly enhance the energy capacities of Mediterranean countries. However, location selection for offshore wind farms (OWFs) is a challenge for renewable energy policy and marine spatial planning (MSP). To address these issues, this study considers the marine space of Greece to propose a GIS-based multi-criteria decision-making (MCDM) framework employing the Analytic Hierarchy Process (AHP) to identify suitable sites for OWFs. The approach assesses 19 exclusion criteria encompassing legislative, environmental, safety, and technical constraints to determine the eligible areas. Subsequently, 10 evaluation criteria are weighted to determine the selected areas’ level of suitability. The study considers baseline conditions (1981–2010) and future climate scenarios based on RCP 4.5 and RCP 8.5 for two horizons (2011–2040 and 2041–2070), integrating projected wind velocities and sea level rise to evaluate potential shifts in suitable areas. Results indicate the central and southeastern Aegean Sea as the most suitable areas for OWF deployment. Climate projections indicate a modest increase in suitable areas. The findings serve as input for climate-resilient MSP seeking to promote sustainable energy development. Full article

Although marine caves are among the most species-diverse habitats in the Mediterranean Sea, most available studies have focused on their sessile fauna. This study provides the first quantitative assessment of motile fauna in 27 marine caves across four geographical subareas of the Aegean and Ionian Seas, using a rapid assessment visual census protocol, applied through 3 min time transects in each ecological cave zone. Multivariate analysis revealed that the motile community structure of the cave entrance was differentiated from that of the semidark and dark zones. Deeper caves were distinct from shallower ones while caves of the east Aegean differed from those around Crete Island. A total of 163 taxa were recorded, 27 of which are reported herein for the first time in marine caves of the eastern Mediterranean Sea, while three species (two native and one introduced) are recorded in Greek waters for the first time, enriching our knowledge on the permanent and occasional cave residents. Seventeen species were introduced, comprising more than half of the total fish abundance in the southeasternmost cave. Our limited knowledge of the motile fauna of Mediterranean marine caves coupled with the continued spread of introduced species highlights the urgent need for monitoring and conservation actions, especially within marine protected areas. Full article

The advanced determination of the type (foreshock–aftershock–swarm) of an ongoing seismic cluster is quite challenging; only retrospective solutions have thus far been proposed. In the period of January–March 2025, a seismic cluster, recorded between Santorini volcano and Amorgos Island, South Aegean Sea, caused considerable social concern. A rapid increase in both the seismicity rate and the earthquake magnitudes was noted until the mainshock of M_L = 5.3 on 10 February; afterwards, activity gradually diminished. Fault-plane solutions indicated SW-NE normal faulting. The epicenters moved with a mean velocity of ~0.72 km/day from SW to NE up to the mainshock area at a distance of ~25 km. Crucial questions publicly emerged during the cluster. Was it a foreshock–aftershock activity or a swarm of possibly volcanic origin? We performed real-time discrimination of the cluster type based on a daily re-evaluation of the space–time–magnitude changes and their significance relative to background seismicity using earthquake statistics and the topological metric betweenness centrality. Our findings were periodically documented during the ongoing cluster starting from the fourth cluster day (2 February 2025), at which point we determined that it was a foreshock and not a case of seismic swarm. The third day after the M_L = 5.3 mainshock, a typical aftershock decay was detected. The observed foreshock properties favored a cascade mechanism, likely facilitated by non-volcanic material softening and the likely subdiffusion processes in a dense fault network. This mechanism was possibly combined with an aseismic nucleation process if transient geodetic deformation was present. No significant aftershock expansion towards the NE was noted, possibly due to the presence of a geometrical fault barrier east of the Anydros Ridge. The 2025 activity offered an excellent opportunity to investigate deciphering the type of ongoing seismicity cluster for real-time discrimination between foreshocks, aftershocks, and swarms. Full article

Recent archaeological discoveries across the Aegean, Cyprus, and western Anatolia have renewed interest in pre-Neolithic seafaring and early island colonization. However, the environmental contexts that support such early coastal occupations remain poorly understood, largely due to the submergence of Pleistocene shorelines following post-glacial sea-level rise. This study addresses this gap through an integrated geoarchaeological investigation of the pre-Neolithic site of Ouriakos on Lemnos Island, northeastern Aegean (Greece), dated to the mid-11th millennium BCE. By reconstructing both the terrestrial and submerged paleolandscapes of the site, we examine ecological conditions, resource availability, and sedimentary processes that shaped human activity and site preservation. Employing a multiscale methodological approach—combining bathymetric survey, geomorphological mapping, soil micromorphology, geochemical analysis, and Optically Stimulated Luminescence (OSL) dating—we present a comprehensive framework for identifying and interpreting early coastal settlements. Stratigraphic evidence reveals phases of fluvial, aeolian, and colluvial deposition associated with an alternating coastline. The core findings reveal that Ouriakos was established during a phase of environmental stability marked by paleosol development, indicating sustained human presence. By bridging terrestrial and marine data, this research contributes significantly to the understanding of human coastal mobility during the Pleistocene–Holocene transition. Full article

Tinos Island, part of the Cyclades Complex in the central Aegean Sea, represents a distinctive case of geocultural heritage where geological formations and cultural identity intersect. This study evaluates the geoeducational and geotouristic potential of Tinos’ geosites using GEOAM methodology, which assesses their scientific, educational, and conservation value. Six geosites are examined to explore their geoeducational potential, including prominent locations such as the Tafoni formations and the Exombourgo granite massif. The findings highlight the significance of these sites, while also identifying challenges related to infrastructure, stakeholder engagement, and sustainable management. By integrating geoethics into geotourism practices, Tinos can adopt a balanced approach that enhances environmental conservation alongside community-driven economic benefits. The study underscores the need for collaborative initiatives to optimize the island’s geoheritage for education and tourism, ensuring its long-term preservation. Geotourism, when responsibly implemented, has the potential to strengthen local identity while advancing sustainable tourism development. Full article

This study presents the living coccolithophore communities and the morphological variability of Emiliania huxleyi in the South Aegean Sea from three sampling regions during winter-early spring (March 2017, March 2019) and summer (August 2019). Emphasis is given to March 2017 to monitor the variations in coccolithophore assemblages after an exceptionally cold event in December 2016, which resulted in newly produced dense waters that ventilated the Aegean deep basins. The assemblages displayed distinct seasonality with the predominance of E. huxleyi and Syracosphaera molischii during winter-early spring, associated with the water column mixing. By contrast, summer assemblages were featured by holococcolithophores and typical taxa of warm, oligotrophic upper waters. It seems that the phytoplanktonic succession as well as the nutrient supply to the upper euphotic layers were affected by the water column perturbation during the extreme winter of 2016–2017, which led to strong convective mixing and dense water formation. The decreased coccosphere densities during March 2017, accompanied by the notable presence of diatoms, were most probably associated with a prolonged diatom bloom, causing delay in the development of the coccolithophore community and resulting in a nitrogen-limited setting. Emiliania huxleyi morphometry showed the characteristic seasonal calcification trend of the Aegean, with the dominance of smaller coccoliths in the summer and increased coccolith length and width during the cold season. The intense cold conditions and wind-induced mixing during the winter of 2016–2017 possibly increased the absorption of atmospheric CO₂ in surface waters, causing increased acidity and the subsequent presence of etched/undercalcified E. huxleyi coccoliths and other taxa, most probably implying in situ calcite dissolution. Full article

Lionfish (Pterois miles), an invasive species in the Mediterranean, pose ecological and socioeconomic challenges. This study examines the seasonal variation in the nutritional composition and technical quality of lionfish from the Ionian and Aegean Seas, evaluating their potential as a food resource. Fillets were high in protein (19.4%) and low in fat (2.0%), with significant seasonal differences in the Ionian Sea, where winter samples had higher lipid content. The fillet yield (28.4%) was satisfactory given the fish’s morphology. Fatty acid analysis confirmed lionfish as a valuable source of polyunsaturated fatty acids (PUFAs), particularly eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), with EPA + DHA levels exceeding the recommended daily intake (119.2%). Seasonal variations in fatty acid composition were observed, including higher EPA in autumn and lower lipid nutritional quality in summer. Arachidonic acid (ARA) was also present at nutritionally significant levels (79.4 mg/100 g). The n3/n6 ratio (2.2) and favourable atherogenic and thrombogenic indices highlight its nutritional benefits. This is the first study to assess seasonal variations in the nutritional value and technical yield of lionfish in the Mediterranean, offering novel insights into its commercial valorisation. These findings support its promotion as a sustainable protein source and as a means of managing its invasive population. Full article

Lethocerus patruelis (Stål, 1854) is a large aquatic hemipteran and the only European representative of the family Belostomatidae. Commonly known as the giant water bug, this species was historically restricted to the Balkans, Anatolia, and parts of the Middle East, but has exhibited a marked westward and northward range expansion in recent decades. In this study, we report the first confirmed occurrence of L. patruelis on Lesvos Island, in the northeastern Aegean Sea, based on a direct observation made within a wastewater treatment facility. The individual was identified in situ using diagnostic morphological traits and photographed without disturbance. This finding extends the known insular distribution of the species and underscores its capacity to exploit anthropogenically modified aquatic systems. Given the island’s rich mosaic of natural and artificial wetland habitats—including over 200 mapped sites—Lesvos may offer suitable conditions for the establishment of local populations. This record highlights the need for targeted surveys and long-term monitoring across under-sampled insular landscapes. Full article

Composite materials have the advantages of high strength and low weight, and are therefore used in many areas. However, in humid and marine environments, mechanical properties may deteriorate due to moisture diffusion, especially in glass fiber reinforced polymers (GFRP) and carbon fiber reinforced polymers (CFRP). This study investigated the damage formation and changes in mechanical properties of single-layer adhesive-bonded GFRP and CFRP connections under the effect of sea water. In the experiment, 0/90 orientation, twill-woven GFRP (7 ply) and CFRP (8 ply) plates were produced as prepreg using the hand lay-up method in accordance with ASTM D5868-01 standard. CNC Router was used to cut 36 samples were cut from the plates produced for the experiments. The samples were kept in sea water taken from the Aegean Sea, at 3.3–3.7% salinity and 23.5 °C temperature, for 1, 2, 3, 6, and 15 months. Moisture absorption was monitored by periodic weighings; then, the connections were subjected to three-point bending tests according to the ASTM D790 standard. The damages were analyzed microscopically with SEM (ZEISS GEMINI SEM 560). As a result of 15 months of seawater storage, moisture absorption reached 4.83% in GFRP and 0.96% in CFRP. According to the three-point bending tests, the Young modulus of GFRP connections decreased by 25.23% compared to dry samples; this decrease was 11.13% in CFRP. Moisture diffusion and retention behavior were analyzed according to Fick’s laws, and the moisture transfer mechanism of single-lap adhesively bonded composites under the effect of seawater was evaluated. Full article

This article documents the first outbreak of aeromoniasis caused by Aeromonas veronii in farmed European seabass (Dicentrarchus labrax) along the Greek Ionian Sea coast. In late spring 2024, commercially sized fish exhibited anorexia, hemorrhages, and ulcers on the skin, accompanied by elevated morbidity and mortality rates. The outbreak spread rapidly across local farms in Sagiada Bay, reaching its peak in late summer, and extending into the Astakos Gulf, southern in the Ionian Sea. The postmortem examination revealed hemorrhages, organomegaly, abscess formation, and granulomatous inflammation. Aeromonas veronii was isolated from all examined individuals in nutrient media and confirmed by biochemical and molecular methods. Whole genome sequencing and phylogenetic analysis demonstrated genetic homogeneity among two strains from two different areas along the Ionian Sea and a close evolutionary relationship with other Aeromonas veronii strains from the Aegean Sea. Although genetically similar, the isolates exhibited differences in phenotypic and biochemical characteristics, indicating regional variability. The present study provides an overview of the pathology, clinical characteristics and progression of aeromoniasis in Ionian Sea aquaculture, highlighting the need for continued monitoring, in-depth genomic and phenotypic assessment, and the design of region-specific preventive strategies, including autogenous vaccines, for effective disease management. Full article

The Atlanto-Mediterranean sea cucumber Holothuria tubulosa is a species of great ecological and commercial importance, making it a primary target for collection in the Mediterranean region. This study investigated the reproductive biology of H. tubulosa (Gmelin, 1793) in a coastal area of the Central Aegean Sea (Eastern Mediterranean) over a one-year period, from June 2021 to May 2022. Monthly sampling was conducted via dives at depths up to 10 m, alongside the recording of environmental and biometric data. Histological analysis revealed a synchronous annual reproductive cycle, with gonadal maturation beginning in April and peak sexual maturity observed in July and August, followed by a single spawning event from August to September. The sex ratio was 1:1.31 (male: female), and the size at first maturity was 255.3 mm. These findings provide essential insights into the reproductive physiology of H. tubulosa and further contribute to the development of sustainable stock management strategies for sea cucumbers in the Hellenic Seas. Full article

The Eastern Aegean Sea hosts a diverse assemblage of elasmobranchs, many of which are vulnerable or endangered. This study presents a fishery-independent assessment of species composition, catch characteristics, and spatial patterns in bottom trawl fisheries between Lesvos Island and Ayvalik. A total of 48 surveys were conducted between September 2022 and October 2024, identifying nine elasmobranch species, with Scyliorhinus canicula (small-spotted catshark) and Mustelus mustelus (common smooth-hound) dominating the catch. Biological parameters, sex ratios, and condition upon capture and release were recorded, while catch per unit effort (CPUE) and diversity indices were used to evaluate temporal patterns. The survival probability was negatively affected by the trawl duration and elevated temperatures, emphasizing the need for mitigation measures. Spatial models revealed high-density zones that likely function as foraging or nursery grounds. Seasonal shifts in community composition were also evident. Many non-commercial species were discarded irrespective of their size or condition. These findings underscore the ecological importance of this understudied region and support the need for spatially explicit, species-specific management strategies, including gear selectivity improvements, seasonal closures, and Electronic Monitoring. The study offers a critical baseline for enhancing the sustainability of elasmobranch populations in the Eastern Mediterranean. Full article

The dispersion of microplastics in the sea is an emerging and crucial environmental problem. In this preliminary study, the hydrodynamics of microplastics transferred from flooded agricultural areas to the sea was assessed. The Daniel storm in 2023 in region of Thessaly, Greece, initiated the transfer of plastic debris via the Pinios River, which subsequently discharged to the coastal basin at the south area of Thermaikos Gulf (NW Aegean Sea). Field sampling and laboratory measurements of microplastics collected at the mouth of the Pinios were conducted. The dispersion of microplastics discharged by the Pinios River is subject to the dominant wind conditions over the area, which in turn determines the water circulation in the NW Aegean Sea. Thus, a hydrodynamic model was initially applied, followed by a transport model for the study of the dispersion of the microplastics. The models were applied for SW and NE winds and indicated that the majority of microplastics with a settling velocity 0.1 m/s accumulate in areas close to the river’s mouth or lateral coastal zones; however, under the influence of SW winds, minor quantities tend to reach the east coasts of the Thermaikos Gulf, while massive quantities are transported away from the river’s mouth in case of microplastics floating on the sea’s surface. Full article

As wind turbine rotors grow in size and Greece advances its offshore wind energy initiatives, this study analyzes the structural behavior of offshore wind turbine blades using fluid–structure interaction (FSI) methods. The blade skin and shear webs of the International Energy Agency (IEA) 15 MW wind turbine, assumed to operate in the Aegean Sea, are examined. Computational fluid dynamics (CFD) simulations are conducted for two steady-state wind speeds based on local weather data, followed by finite element analysis (FEA) to assess advanced materials in terms of strength, cost, and carbon footprint. This is the first study to evaluate bamboo- and basalt-based composite materials under Greek offshore wind conditions using FSI methods. Bamboo composites are affordable and sustainable, but their limited durability reduces their viability in offshore environments. The simulation results indicate that using bamboo composites as blade skin may lead to damage due to the excessive loads on offshore wind turbine blades. In contrast, basalt fiber composites are also environmentally viable and offer superior strength, corrosion resistance, and long-term performance, making them a promising alternative. However, their naturally high density may impact the overall weight of the structure. This study concludes that offshore wind technology in the Aegean is feasible but remains costly and environmentally demanding. The further development and adoption of basalt fibers may serve as a gateway to more environmentally friendly offshore structures. Full article

Argonauta argo (Linnaeus, 1758), commonly known as the greater argonaut, is a pelagic octopod with a circumglobal distribution in warm and temperate seas. Although the species is occasionally reported in the Mediterranean Sea, confirmed in situ observations of live individuals remain scarce, particularly in the eastern basin. Here, we document the occurrence of a live female A. argo entangled in aquaculture nets at a sea bass (Dicentrarchus labrax) facility off the coast of Lesvos Island in the northeastern Aegean Sea, Greece. This represents the first confirmed observation in this part of the Mediterranean and only the second confirmed observation of a live individual in Greek waters. The individual was photographed in situ and identified based on diagnostic morphological features. The encounter occurred under specific hydrodynamic and environmental conditions potentially favorable to the species, including enhanced prey availability and structural refuge within the aquaculture infrastructure. This record contributes to the limited dataset on Mediterranean argonauts and underscores the need for further research into their ecology, distribution patterns, and potential interactions with anthropogenic marine structures. Full article