Aegean Sea Research Articles

Ten Years of Mediterranean Monk Seal Stranding Records in Greece under the Microscope: What Do the Data Suggest?

This paper presents the results of an analysis of stranding events of the Mediterranean monk seal Monachus monachus over a decade. The analysis involved categorization according to the cause of stranding and seasonality, the identification of hotspot stranding areas and an assessment of possible correlations between stranding events and environmental/climatic patterns using time series analysis. Moreover, Generalized Additive Models (GAMs) were applied to explore the effects of the size of small-scale fishing grounds, the number of species sightings, and the occurrence of reproduction sites on "human-related" strandings. Finally, special focus was put on the central part of the eastern Ionian Sea for the assessment of stranding hotspot areas by means of the Multi-Criteria Decision Analysis (MCDA) approach, based on different kinds of spatial information such as anthropogenic pressures and the location of breeding sites and feeding grounds. Time series analysis results revealed that oscillation indices, during the first half of the year, and sea surface temperature (SST) in the Mediterranean from October to December were positively correlated with monk seal stranding events. GAMs underlined that areas combining extended small-scale fishery grounds and a higher number of sightings were more likely to cause more strandings. Regarding spatial analyses, the central Aegean Sea was highlighted as a hotspot for "human-related strandings", while the MCDA approach emphasized that the southern coasts of Cephalonia and the gulf between Lefkada and mainland Greece were susceptible to subadult strandings.

Evaluation of the exposure of the Mediterranean biodiversity to marine litter: the ASI – plastic busters MPAs projects connection

A number of marine species in the Mediterranean are threatened by the presence of several pressure factors, which include climate change, collisions with vessels, entanglement and ingestion of marine litter, especially plastic. Risk reduction policies can only be conceived starting from an accurate analysis of the exposure to such pressure factors. To estimate spatial abundance of both marine species and plastic litter and to assess the exposure risk, a two-stage analysis approach was applied, using aerial survey data from the ACCOBAMS Survey Initiative (ASI), in synergy with the Plastic Busters MPAs (PB MPAs) project. First, a detection function was fitted to observation data to obtain detection probabilities for individuals, then a Generalized Additive Model (GAM) was employed to estimate the spatial distribution of relative abundance, based on survey observations. A bivariate Local Indicator of Spatial Association (LISA) was then applied to the maps of relative abundance to derive risk maps of exposure of marine species to marine litter. The maps, obtained with a spatial resolution of about 10 km, allow us to identify areas with the highest neighboring abundance of taxa and marine litter, in particular for the MPAs studied by the PB MPAs project, which include the North-Western Mediterranean (Pelagos Sanctuary and Tuscan Archipelago), the Ionian and Aegean Sea (Zakynthos), and the Strait of Sicily (Cabrera Archipelago).

Holocene records of oyster reefs in a shallow semi-enclosed island embayment of the Aegean Sea

A high-resolution survey in the semi-enclosed Kalloni Gulf (Lesvos Island, NE Aegean Sea) revealed a plethora of oyster reef structures. The reefs have a relief of up to 6 m high and a length of 1.4 km at the deepest part (∼17 m) of the surveyed area and are developed in a fine-grained seabed. Acoustic backscatter variations caused by the presence and the type/distribution of different reef structures were mapped, resulting in the identification of four backscatter types. Sub-bottom acoustic information revealed the presence of similar buried features, which were classified in three types according to their characteristics. The seismic stratigraphy also showed the Holocene highstand and the transgressive system tracts as well as a deeper-seated distinct erosional surface with numerous buried channels, most likely corresponding to the surface flooded during the Holocene marine transgression. Starting at around 9700 years BP, the Kalloni paleo-landscape was progressively submerged and gradually transformed into a shallow, land-locked marine environment, allowing the establishment, and thriving of oyster reefs. The buried reefs presumably began to grow during the early stages of the gulf's transgression, whereas most of the modern reefs were developed/maintained by the modern hydrodynamic/sedimentary regime. It is the first time that such a large occurrence of well developed, diachronic oyster reef assemblage has been documented in the transgressive coastal environments of the microtidal Mediterranean Sea, but further research is required to determine the exact mode of their development.

Sociodemographic Trends in Planetary Health Diets among Nutrition Students in Türkiye: Bridging Classroom to Kitchen.

This study aimed to investigate the effects of sociodemographic parameters on healthy and sustainable nutrition in nutrition students. This cross-sectional study was conducted with 601 students. Researchers administered questionnaire forms to gather sociodemographic information such as age, gender, geographical region, residence area, accommodation, BMI, and income level. Participants' 24 h dietary records were used to evaluate Healthy Eating Index-2020 (HEI-2020) and Planetary Health Diet Index (PHDI). The mean PHDI scores of the Marmara (53.4 ± 14.9), Aegean (58.2 ± 18.3), Mediterranean (55.3 ± 15.5), and Black Sea (55.5 ± 15.7) regions, which are the coastal regions of Türkiye, were significantly higher than for the Central Anatolia region (46.7 ± 15.1). The PHDI and HEI-2020 score means of students living in metropolitan cities and rural areas were significantly higher than those living in urban areas (p < 0.05). Being in the 20-25 years age group increased the probability of being in a lower PHDI group (AOR 1.82; 95% CI 1.07:3.12; p = 0.028). While a similar result was found in the 20-25 years age group for HEI-2020, income level and gender did not have a statistically significant effect on these scores. Since students' ages, geographical regions, and residence areas affect PHDI and HEI-2020, it is considered important to take these sociodemographic variables into consideration in guidelines and studies.

Age, Growth, and Otolith Morphometrics of Trachinus draco (L., 1758) and Trachinus radiatus (Cuvier, 1829) in the Eastern Mediterranean

Trachinus draco and Trachinus radiatus are two bycatch species of low commercial value and no sufficient knowledge on their biological features. In the present study, the weight–length relationship, age, growth, and ten otolith morphometric variables of these species were investigated in the southwestern Aegean Sea for the first time. Positive allometric and isometric growth in the weight were defined in T. draco and T. radiatus. The weight–length relationship was described by the parameters α = 0.002415 and b = 3.35745 in T. draco and α = 0.007582 and b = 3.09452 in T. radiatus. The von Bertalanffy growth function parameters were L∞ = 44.51 cm, k = 0.15 year−1, and t0 = −1.31 years for T. draco and L∞ = 58.47 cm, k = 0.16 year−1, and t0 = −0.78 years for T. radiatus. Ten otolith variables (radius, length, width, area, perimeter, roundness, circularity, form factor, rectangularity, and ellipticity) showed a significant relationship with size for both species, except the ellipticity in T. radiatus. The mean values of all the otolith variables were higher in T. radiatus than in T. draco. The otolith of T. radiatus was found to become more rectangular with size as compared to the otolith of T. radiatus. The results of this work can support further research on the behavioral and ecological features of the two species.

Imprints of Holocene aridity variability in the Aegean Sea and interconnections with north-latitude areas

The analysis of the ASTC1 sediment core from the south Aegean Sea region offers critical insights into the complex interplay of geological and climatic factors over the Holocene period. The data reveals fluctuating climatic conditions during the last 8.7 ka as seen through the elemental concentrations obtained by XRF core scanning combined with a qualitative mineral analysis within a robust chronological framework. Short-term fluctuations in both Ti/Al and Zr/Si ratios suggest brief oscillations of increased aridity which partially coincide with the Holocene “Rapid Climate Change” events (RCCs). Among them, the most pronounced in our record are those centered between 8.5–8 ka, 3–2.5 ka (Greek Dark Ages), and 0.6–0.3 ka (Little Ice Age). The arid and humid events identified in the sediment record align with major archaeological periods in Greece, suggesting a potential influence of climatic conditions on the development and decline of civilizations in the region. Moreover, a general arid trend as of 6 ka toward the present was evidenced in our record and aligns with other high-resolution climatic data from the Northern Hemisphere, suggesting climatic teleconnections. Spectral analysis of the ASTC1 record reveals cyclical climate patterns with periodicities of approximately 2500, 1200, and 550 years, which coincide with the Bond and Hallstatt cycles. The phase relation of these cycles in our record, the Greenland ice record, and the North Atlantic Drift ice indices show that colder conditions in the higher latitudes are expressed as events of enhanced aridity in our record and generally in the lower latitudinal regions.

Ecological Impacts of Introduced European Rabbits (Oryctolagus cuniculus) on Island Ecosystems in the Mediterranean

The Cyclades Islands (Aegean Sea, Greece) are part of the Mediterranean Basin biodiversity hotspot and harbor a plethora of endemic species. Plant communities on the smaller islands in this region have largely evolved in the absence of herbivory and frequently lack antiherbivore defenses. This study evaluates the short- and long-term effects of the European rabbit (Oryctolagus cuniculus), an herbivore that has been released on numerous islands in the region, by comparing islands that 1. have historically been rabbit-free (ungrazed); 2. are currently grazed by rabbits, and 3. have previously been grazed, but are now rabbit-free. Ecological impacts of rabbits on the Aegean Islands were investigated by assessing the abundance, composition, and diversity of plant and arthropod communities as well as soil characteristics. Our results indicate that ungrazed islands have more arthropod species, more specialized or endemic plant species, and less exposed soil than currently grazed islands. While ungrazed islands did not necessarily possess higher total plant species richness, they did harbor significantly more small-island endemic taxa relative to presently grazed islands. This study indicates that native plant communities on Mediterranean islets are not adapted to the presence of this introduced species and that the practice of intentionally releasing rabbits on islands has significant and lasting negative ecological impacts, especially on small islands. While a complete recovery of post-rabbit was not evident over the time span of our research, both arthropod and plant data indicate that partial recovery is possible once rabbits have been removed.

Shear-wave splitting associated with fluid processes beneath Styra, South Euboea: First results

The intense and persistent seismic activity on the Island of Euboea (or Evia) was a unique opportunity to study anisotropy in a region without any notable prior seismicity. The study area is located in the central-western Aegean Sea and constitutes the endpoint where the North Aegean Trough and four parallel dextral strike-slip fault branches terminate against the Greek mainland, along with their sinistral counterparts. Even though seismicity has been recorded around the island, the affected area close to the town of Styra has no known reported earthquakes. In 2022, surprising activity was initiated by two moderate earthquakes (ML 4.8 and ML 5.0) that occurred on 29 November and were felt as far as Athens. The activity continued well into the second quarter of 2023, with over 1000 microearthquakes being recorded. A pre-planned nearby temporary installation of a broadband instrument (GR27), in the context of the AdriaArray project, offered recordings of the activity. Here, we investigated the occurrence and cause of shear-wave splitting beneath Styra. Based on focal mechanisms of local earthquakes we inferred the stress axes. A fully automated process was used to analyze data for shear-wave splitting and determine the polarization direction of the Sfast (φ), the time-delay (td) and the normalized time-delay (tn). A total of 272 acceptable results showcased a unimodal distribution of φ with an average of N68°E and a mean td of 80 ms. We observed temporal variations of splitting parameters, associated with outbursts of seismicity, not with individual events. The determination of the shear-wave velocity anisotropy, jointly with observations of other splitting parameters, led us to hypothesize that anisotropy is the result of along-fault fluid processes. However, this would require a convincing selection of the NE-SW nodal plane as the preferred fault orientation. Further enrichment of the catalogue and an increase in splitting results is required to draw more robust conclusions.

Determining climate classifications and producing climate border maps with GIS of Muğla province on the southern Aegean Sea coast of Türkiye

Climate is defined by the average of meteorological events observed over an extended period in a region, expressing the weather conditions of that area. Numerous scientists have developed various climate classifications. The fundamental purpose of these classifications is to distinguish different types of climates and thereby reveal similarities between regions. Such classifications can be based on factors like temperature and precipitation patterns. Understanding climate characteristics enables us to determine the boundaries of different climate types. This, in turn, is crucial for ensuring the sustainable use of regional resources and shaping land use plans. This study evaluates the process of creating climate boundary maps for Muğla province. Various climate classification methods, including Thornthwaite, Trewartha, Erinç, De Martonne, Köppen─Geiger, and Köppen, are comprehensively examined and compared. Our findings indicate that each method offers different approaches to defining Muğla’s climate, each with its unique advantages and limitations. For instance, while the Thornthwaite method provides detailed data, the Köppen─Geiger method offers a more generalized approach. The results suggest that combining various climate classification methods helps in more accurately and comprehensively mapping the climate boundaries of Muğla province. This study underscores the importance of integrating these diverse methods to contribute to the determination of climate boundaries and regional planning processes.

The Current Status of Viral Nervous Necrosis Disease in Türkiye

The agent of Viral Nervous Necrosis (VNN) disease is betanodavirus and is a viral fish disease and VNN disease has been reported in many fish species in Türkiye and around the world. It is known to cause high mortality rates in aquatic animals living in both marine and fresh water. It has been reported that the RGNNV and RGNNV/SJNNV genotypes of the virus, which has four genotypes, were detected in Turkey by the end of 2023. RGNNV genotype was detected in sea bass (Dicentrarchus labrax) for the first time in our country in 2011 and after that has since been found in other fish species such as sea bream (Sparus aurata), red mullet (Mullus barbatus), and garfish (Belone belone) in the Mediterranean region. RGNNV genotypes have also been reported in sea bass (D. labrax) in the Black Sea, and in sea bass (D. labrax) and RGNNV/SJNNV genotypes have been reported sea bream (S. aurata) in the Aegean Sea. In this study, studies on VNN in Turkey were reviewed and it was aimed to discuss the current status of the disease as a whole.

Two new species of planktonic Caligus O.F. Müller 1785 (Copepoda: Caligidae) from Türkiye with an updated review and checklist of planktonic caligids

Two new species of caligid sea lice, Caligus izmiriensis sp. nov., and Caligus sarosensis sp. nov. are described, based on specimens collected from the zooplankton in the Gulf of Sığacık and the Gulf of Saros off the Aegean Sea coast of Türkiye. Detailed examination of the morphology of these two new species and comparisons with other closely related caligid species, especially Metacaligus yucatanensis Suárez-Morales, Kim &amp; Escamilla, 2012, resulted in the recognition of the genus Metacaligus Thomsen 1949 as a junior synonym of Caligus O.F. Müller, 1785. Based on this proposed synonymy, all species of the genus Metacaligus are here transferred to Caligus: Metacaligus trichiuri (Krøyer, 1863), M. rufus (Wilson, 1908), and M. unguidentatus (Rangnekar &amp; Murti, 1950) all return to their original combinations as Caligus trichiuri Krøyer, 1863, Caligus rufus Wilson, 1908, and Caligus unguidentatus Rangnekar &amp; Murti, 1950, respectively; Metacaligus yucatanensis Suárez-Morales, Kim&amp; Escamilla, 2012, becomes Caligus yucatanensis (Suárez-Morales, Kim &amp; Escamilla, 2012) comb. nov.; transferring Metacaligus latus Ho &amp; Lin, 2002 would create a secondary homonym of Caligus latus Byrnes 1987, so a replacement name is proposed as Caligus cultellus nom. nov. We recognise C. yucatanensis as a member of the C. undulatus-group. The four other species previously placed in Metacaligus form a cluster which represents a new species group, the Caligus trichiuri-group. An updated list of planktonic caligids is presented, together with keys to species of the C. undulatus-group and of the newly proposed C. trichiuri-group. The subgenus Subcaligus Heegaard, 1943 was originally proposed to accommodate Caligus (Subcaligus) bocki Heegaard, 1943, and was characterised by its unusual stylet-like sternal furca. This subgenus has not been treated as valid by subsequent authors and we here formally propose to treat Subcaligus Heegaard 1943 as a junior synonym of Caligus.

State of the surface waters in the Mesta River basin, after the reclamation of the Eleshnitsa uranium deposit

In the period from 1955 to 1992, uranium ore was mined and processed in the Mesta River basin around the village of Eleshnitsa, region of Razlog. The ore processing plant was built and a tailings storage facility was built next to it. In the period 2002&amp;ndash;2006, the tailings storage was reclaimed, and in 2011&amp;ndash;2012 the ore mines were also reclaimed. For the treatment of drainage water, a treatment plant was built in the valley of Valchoto Dere River, a left tributary of the Mesta River. The radiological monitoring carried out by the Basin Directorate &amp;ldquo;West Aegean Sea Region&amp;rdquo; reveals a generally good quality of the surface waters in terms of the content of uranium and radium (226Ra) outside the area of the former uranium mining and the tailings storage facility. In this area, in some years a high content of natural uranium was found, with concentrations from 0.54 to 67.40 mg/l on average per year. The values significantly exceed (by 1.8 to 224.6 times) the norm regulated in the regulation for radiation protection and safety from the liquidation of the consequences of uranium mining. The spread of uranium is limited to a small area shortly downstream from the sources of contamination, but the potential risk to the local ecosystem should not be neglected. Radium, in contrast to uranium, has concentrations below the permissible limits in the twelve years studied. Its content varied from 0.025 to 0.11 Bq/l on average annually. The results show that the Mesta River near the border with the Republic of Greece is not contaminated with the studied radionuclides.

GIS-based floating offshore wind turbine installation site selection using fuzzy analytic hierarchy process in northeast Aegean Sea

The ever-increasing consumption of electrical energy due to increasing requirements arising in parallel with the developing technology forces manufactures and users to seek new and environmentally compatible energy resources. Due to it endless energy potential and continuity, wind energy, which has been used by humanity for various purposes for centuries, continues its journey, which started with windmills that transform one form of mechanical energy into another, with offshore wind energy turbines. In this study, installation site selection, which is the first step for floating offshore wind turbine installation, is carried out. First, a Fuzzy Analytic Hierarchy Process (F-AHP) is applied to obtain the weights of criteria. Transformed alternatives and criteria in a fuzzy decision matrix through triangular fuzzy numbers are used to obtain a database via a Geographic Information System (GIS). Finally, the installation site and study area are determined. This area is located in the Northeast Aegean Sea, between Çanakkale and Gökçeada, 12 km to the northeast of Gökçeada, and 12 square kilometers. The minimum distance of the area to ship routes is 3000 m, and its minimum distance to fault lines is 2000 m. The average sea depth is 110 m, and the average wind speed is 9.26 m/s (18 knots). With this potential, enough energy can be generated for settlements on Gökçeada and the coastlines.

The Upper Crustal Deformation Field of Greece Inferred From GPS Data and Its Correlation With Earthquake Occurrence

AbstractWe present a new geodetic strain rate and rotation rate model for Greece that has been derived using a highly dense GPS velocity field. The spatial distribution and the resolved rates of the various velocity gradient tensor quantities provided updated constraints on the present‐day upper crustal deformation in the region and revealed new details not reported previously. The spatial distribution of the second invariant demonstrated that the overall magnitude of strain rates is highest across two well‐defined provinces. The first follows the North Anatolian Fault and its two branches within the north Aegean, crosses central Greece and through the Gulf of Corinth it terminates in western Greece, while the second encompasses the extensional province of western Turkey and the eastern Aegean Sea islands. Our estimates revealed that shearing affects some of the fault‐bounded grabens of central Greece that lie to the SW of the North Aegean Basin implying considerable oblique extension. We identified a narrow region of counterclockwise rotation whose location and kinematics have been induced by the net effect across the intersection of the clockwise rotating domains of western and central Greece. The Aegean microplate and the Anatolian plate are separated by a wide transition zone which accommodates the curved stretching of the entire plate system. In both edges of the Hellenic forearc the dominant mode of crustal strain is E‐W extension. We found that earthquakes of M ≥ 5.6 are spatially well‐correlated with high‐strain areas, indicating that strain rate mapping could be used to inform future probabilistic seismic hazard analyses.

Phytoplankton Species Composition in the Turkish Coast of the Aegean Sea between 2014 and 2016

The research was carried out between 2014 and 2016, within the scope of the ‘National Integrated Marine Pollution Monitoring Program,’ in a total of five seasonal cruises at 22 stations along the Turkish coast of the Aegean Sea. A total of 296 phytoplankton species and one subspecies belonging to 12 classes were identified from samples collected during the five seasonal cruises. The highest diversity was observed in the summer of 2015, with 204 species recorded, while the lowest was 137 species in the summer of 2016. Dinoflagellates dominated the species composition, accounting for 51% of the species, followed by diatoms (44%), and other groups (5%). At the genus level, Chaetoceros, Thalassiosira, Bacteriastrum, and Coscinodiscus were the most dominant diatom genus, whereas Protoperidinium, Tripos, Dinophysis, Oxytoxum, and Prorocentrum were dominant among dinoflagellates. Amphisolenia schauinslandii Lemmermann 1899 and Ceratoperidinium margalefii A.R. Loeblich III 1980 were recorded for the first time along the Turkish coast of the Aegean Sea. This study provides a comprehensive assessment of the phytoplankton taxonomic diversity in the region from to 2014-2016.

Effect of the aquaculture on the seagrass Posidonia oceanica: a decade before and after in the Aegean Sea

Seagrass Posidonia oceanica is an endemic and a keystone marine plant in the Mediterranean Sea. It has been a decline in the distribution of P. oceanica meadows by several anthropogenic pressures (i.e. pollution, marine transportation, intensive coastal use, overfishing by ground scanning methods, anchors, aquaculture activities, alien and invasive species, overgrazing, tourist activities). The aim of this study, to evaluate impact of a fish farm in a island (Kızkulesi Island, Dikili, İzmir) on the seagrass Posidonia oceanica meadow from the Aegean coasts of Türkiye. Sampling was made in 2014 September and 2023 October between 0 and 30 m depth by scuba diving. P. oceanica meadow has been completely lost in a decade in the research site.

Abundance, characteristics, and potential ecological risks of microplastics in some commercial fish in İzmir Bay (Aegean Sea, Türkiye)

Marine ecosystems are known to be contaminated by microplastics (MPs); however, the nature and the accumulation rates of microplastics in organisms with different lifestyles and feeding behavior are not well known. To contribute to the clarification of the subject, the present study was conducted by examining the gastrointestinal tract of 366 fish individuals belonging to 13 species, collected by commercial fishermen in İzmir Bay (Aegean Sea). MPs were detected in all fish species and the average number was found to be 2.21 ± 40.7 items ind.–1. Fibers were the most frequently extracted type of MPs. The most frequently identified MPs were black and not larger than 3 mm. By using the ATR-FTIR spectroscopy on MPs obtained from fish species, it was determined that the most frequently consumed plastic polymers were polypropylene (PP, 34.5%) and polyethylene terephthalate (PET, 32.2%). MPs were detected in all fish species examined. In order to reduce MPs in the aquatic ecosystem, it is suggested that in the short term, single-use plastic products should be banned and the use of environmentally friendly products should be promoted, while in the medium term, awareness should be raised by emphasizing training in the use of these products, and in the long term, all nations should fulfil the commitments of the Global Plastic Environment Treaty and ensure their follow-up.

Insular dwarfism in horses from the Aegean Sea and the Japanese archipelago

The horse (Equus caballus) varieties from Skyros and Rhodes islands (Greece) in the Aegean archipelago are extremely small, reaching shoulder heights of only about 1 m. Furthermore, the Japanese archipelago is home to eight small, native horse breeds. We investigated the evolutionary morphology and provided a review of historical documentations of these horses of cultural interest in Greece and Japan, thus providing a comparison of the independent evolution of small size in islands. We integrate cranial data from historical literature with data from newly gathered and curated skulls and analyse a measurement dataset featuring various domestic and mainland horse breeds and varieties. We use non-invasive imaging to study and measure 3D models of the bony labyrinth, housing the inner ear, and the braincase endocast. When considering the effects of allometry by regressing each PC1 scores (for each set of measurements) with the cranial geometric mean from linear measurements as a body size proxy, we show that size explains a large amount of the shape variation in horse crania, the bony labyrinths and brain endocasts. We found high intrabreed variation in all the analysed datasets. Globally, there are at least 30 distinct horse populations on islands, offering the chance to further study processes of convergence in morphological divergence and evaluate the effect of drift and the environment.

Post-Analysis of Daniel Extreme Flood Event in Thessaly, Central Greece: Practical Lessons and the Value of State-of-the-Art Water-Monitoring Networks

Storm Daniel initiated on 3 September 2023, over the Northeastern Aegean Sea, causing extreme rainfall levels for the following four days, reaching an average of about 360 mm over the Peneus basin, in Thessaly, Central Greece. This event led to extensive floods, with 17 human lives lost and devastating environmental and economic impacts. The automatic water-monitoring network of the HIMIOFoTS National Research Infrastructure captured the evolution of the phenomenon and the relevant hydrometeorological (rainfall, water stage, and discharge) measurements were used to analyse the event’s characteristics. The results indicate that the average rainfall’s return period was up to 150 years, the peak flow close to the river mouth reached approximately 1950 m3/s, and the outflow volume of water to the sea was 1670 hm3. The analysis of the observed hydrographs across Peneus also provided useful lessons from the flood-engineering perspective regarding key modelling assumptions and the role of upstream retentions. Therefore, extending and supporting the operation of the HIMIOFoTS infrastructure is crucial to assist responsible authorities and local communities in reducing potential damages and increasing the socioeconomic resilience to natural disasters, as well as to improve the existing knowledge with respect to extreme flood-simulation approaches.

Trajectories of trace element accumulation in seagrass (Posidonia oceanica) over a decade reveal the footprint of fish farming

To evaluate the effect of trace element (TE) release from fish farms on seagrass Posidonia oceanica, we compared TE concentrations (As, Cd, Co, Cu, Mn, Mo, Ni, Pb, V, Zn) in shoots near fish cages (Station ‘Cage’) with those away from them (Station ‘Control’) in two fish farm facilities (Site 1 and Site 2, North Aegean Sea, Greece). We assessed the present (i.e., 2021, year of sampling) and past (reconstructed period 2012–2020) accumulation of TEs using the living compartments (leaf blades, sheaths, rhizomes, roots, epiphytes) and the dead sheaths, respectively. We also assessed possible seagrass degradation by reconstructing past rhizome production. P. oceanica rhizome production at the ‘Cage’ stations was up to 50% lower than at the ‘Control’ stations. Most TE concentrations were higher at ‘Cage’ stations, but the differences often depended on the seagrass living compartment. Significant differentiation between ‘Cage’ and ‘Control’ stations was observed based on the TE concentrations of the dead sheaths during 2012–2020. The contamination level at the ‘Cage’ stations was mostly moderate in Site 1 and low in Site 2, during the reconstructed period, while an increasing contamination trend was found for certain potential phytotoxic TEs (As, Cu, Cd, Mo, V). Our results emphasize the need for the aquaculture industry to work towards a more ecologically aware approach.