South Aegean Research Articles

Lethal grip for an endangered endemic frog: The freshwater crab Potamon karpathos (Decapoda, Potamidae) preys on Karpathos water frog Pelophylax cerigensis (Anura, Ranidae)

Invertebrate predation on amphibians is widespread, although unreported in Europe. Here, we present documented predation of the Karpathos water frog (Pelophylax cerigensis) by the crab Potamon karpathos. Pelophylax cerigensis is an endangered, endemic species exclusively found on the Rhodes and Karpathos Islands in the South Aegean Sea, Greece. The Karpathos population is at risk due to limited suitable habitats and a scarcity of freshwater bodies on the island. From April to October, when there is no rain on the island, frogs and crabs cohabitate, sharing the same shallow ditches. Incidents of frog predation by crabs are common, indicated by numerous individuals with amputated limbs and scars, representing an additional threat to the endangered frog. Further research on the interactions between the two species is urgently required, as it has direct conservation implications.

Towards a more realistic estimation of urban land take by combining cadastral parcels and building footprints

Despite its importance as a research issue, a widely accepted methodology of estimating land take resulting from urbanization has not yet been reached. Accurate geospatial datasets are currently available at a European and global level; however, different methods of quantifying urban land take could lead to diverse outputs, potentially resulting in underestimation. This can be alarming as encroaching urban sprawl is emerging as a major environmental challenge by destroying natural habitats, consuming productive agricultural land, and contributing to climate change by increasing energy demands. To address this knowledge gap, we propose an estimation of urban land take that combines cadastral parcels and building footprints. Land parcels can be considered as a suitable minimum mapping unit as they are directly related to the spatial level where economic decisions on land use conversion are made. The proposed geospatial method is compared to methods that depend on datasets of High Resolution Layer Imperviousness, Global Building Footprints (alone), Corine Land Cover, Urban Atlas, and Global Human Settlement Layer. The method is exemplified in case studies in Greece, specifically: (a) two islands of the South Aegean Region (Mykonos and Thera), that are heavily impacted by tourism development and sprawl and (b) a peri-urban zone (Thermaikos-Michaniona) within the metropolitan area of Thessaloniki, impacted by intense suburbanization. Results show that urban land consumes important shares of available land since the mid-20th century, this fact highlighting the dynamic encroachment of urban development. Calculation shows that other methods could underestimate urbanized areas by up to 80%–90%. In the discussion section, the advantages of shifting the focus from the pixel to the parcel are further justified, while explicit links to spatial planning policies for sprawl containment are drawn. Such policies could be informed by more realistic estimations of urban land take, in order to proceed with strategic and regulatory measures to support the ‘no net land take’ policy of Europe.

Tropical Isognomonids in the Mediterranean Sea: When the West Atlantic Met the Indo-Pacific Region in the South Aegean Sea

Tropical Isognomonids in the Mediterranean Sea: When the West Atlantic Met the Indo-Pacific Region in the South Aegean Sea

Dense Water Formation Variability in the Aegean Sea from 1947 to 2023

The formation of dense water in the Aegean Sea is important as it affects the deep circulation and the hydrography of the Eastern Mediterranean Sea. In this study, the variability of dense water formation is investigated in relation to forcing mechanisms from 1947 to 2023 in the subbasins of the Aegean Sea, utilising in situ observations from various sources, which have been analysed in combination with satellite altimetry and reanalyses products. The analysis reveals that the Aegean Sea has been in a state of increased dense water formation since 2017 due to the combination of increased surface buoyancy loss and reduced Black Sea water inflow. Extremely high salinity has been recorded in the intermediate layers of the Aegean Sea since 2019. The anticyclonic circulation of the North Ionian gyre during 2017 and 2018 probably also contributed to the rapid transport of highly saline waters in the intermediate and, through dense water formation, the deep layers of the Aegean Sea in 2019. Until 2022, the dense waters formed during the peak of the Eastern Mediterranean Transient still occupied the bottom layers of some deep subbasins of the North and South Aegean; however, the 29.4 kg m−3 isopycnal in the North Aegean and the 29.3 kg m−3 isopycnal in the Southeastern Aegean have gradually deepened by 800 m, permitting the waters forming in the last ten years in the Aegean Sea to settle at ever greater depths. Temperature controls the density variability of the Cretan intermediate water up to the decadal time scale. Increased data availability since 2010 was sufficient to clarify that intrusions of dense water from the North–Central Aegean Sea contributed to the erosion of the Eastern Mediterranean transitional waters in the South Aegean Sea after 2017, as well as to raising the intermediate water masses of the South Aegean to shallower depths. The erosion of the transitional Mediterranean waters in the South Aegean Sea between 1947 and 1955 and 1973 and 1980 coincided with increased dense water formation in the North–Central Aegean Sea. During the peak of the Eastern Mediterranean Transient, the North Ionian circulation, the Black Sea water inflow, the Atlantic Multidecadal Oscillation, and the surface buoyancy fluxes favoured dense water formation in the Aegean Sea.

Beyond Borders: Dirofilaria immitis Infection in Dogs Spreads to Previously Non-Enzootic Areas in Greece-A Serological Survey.

Although Dirofilaria immitis in dogs is considered enzootic in northern Greece, the available data on the occurrence of infection in southern parts of the country demonstrate its scarcity. The aim of this study was to update the current knowledge on D. immitis infection in dogs in areas of Greece previously considered non-enzootic (Central Greece, Attica, Peloponnese, North Aegean, South Aegean, Crete and the Ionian islands). In total, 1528 dog blood samples were collected from the aforementioned areas and examined by Dirochek® ELISA (Synbiotics). Additionally, data published until 2022 on the prevalence of infection in these areas were compared to the data of this study. The 'Wilson' Score interval method (Epitools) was employed. Overall, 10.8% of dogs were positive for D. immitis. In detail, the prevalence was 21.7, 13.7, 10.7, 5.4, 4.7, 6.2 and 17.0% for D. immitis, in Central Greece, Attica, Peloponnese, North Aegean, South Aegean, Crete and the Ionian islands, respectively. Infection with D. immitis is recorded for the first time in Crete. The probability of a dog becoming infected has increased 4.1 times since 2022 in previously non-enzootic areas. This study denotes the spread of D. immitis and highlights the necessity for preventive measures.

Non-native fish species in the North Aegean Sea: a review of their distributions integrating unpublished fisheries data

Fisheries-dependent data and information gathered through fisheries-related scientific surveys can significantly contribute to research on the patterns and processes underlying marine biological invasions and their interactions with fisheries. This study presents an overview of the presence of non-native fish species in the North Aegean Sea, offering insights into their distributions and impact on fisheries. The findings are based on a comprehensive compilation of commercial fisheries-dependent and scientific survey data collected in Greece from 2016 to 2023, along with a systematic review of the international scientific literature. The study resulted in the documentation of the presence of 37 non-native fish species, including several recorded for the first time in the area. The results suggest that non-native fish species invasions in the North Aegean Sea are dynamic. Although most species were classified as casual, and the frequencies of occurrence as well as the quantities in commercial fisheries catches of established species are smaller than in the South Aegean Sea, species introductions and the extent of occurrence and area of occupancy of several species have been increasing since the 2000s. The significance of non-native fish species is becoming increasingly relevant to commercial fisheries in the study area. This is particularly evident in the Northeastern Aegean Sea, where catches of non-native species are on the rise, and new species with potential commercial value have emerged in recent years.

Blue crabs (Callinectes sapidus Rathbun, 1896): Initial Adaptation Studies (Brachyura: Portunidae)

The purpose of this study was to determine the blue crab's growth parameters and explore potential adaptations while it was kept in an earthen pond for ninety days. After samples from October 2012 and August 2013 were analyzed, the breeding and biological characteristics of the blue crab (Callinectes sapidus Rathbun, 1896) in the South Aegean were determined. Blue crabs' adaptation to the earth pond, growth circumstances, and morphometric measuremalets using information from the literature are discussed. The process of adaptation took a week, during which time individual blue crabs were seen to begin feeding. The Ege the University Faculty received nine units from the Pond in the Kusadasi/Güzelçamlı area that were examined in cages with 108 distinct experimaletal groups of persons out of 20 living humales.

The Cretan Basin (South Aegean Sea, NE Mediterranean) in the Early Pliocene: a paleoceanographic reconstruction

The Aegean Sea (NE Mediterranean) represents a key area for climatic and oceanographic future projections, therefore it is crucial to define its environmental evolution during the Pliocene paleoclimatic analogue. The DSDP Site 378, located in the South Aegean Cretan Basin, provides an exceptional opportunity to investigate in detail the paleoceanographic conditions of the Early Pliocene and to examine the basin's paleoenvironmental evolution, through the study of calcareous nannofossil accumulation rates and hydroclimate proxies. The sequence has been dated in between ∼5.2–3.9 Ma, with the age of the first Zanclean marine sediments overlying the Messinian Primary Lower Gypsum demonstrating that the Cretan Basin was partially desiccated for at least ∼400 kyrs, as a result of being a shallow epicontinental area in the Late Miocene. A relatively sudden change to deep marine environment took place in the Early Pliocene linked to the accelerated rate of trench extension in the Cretan Basin. The multi-proxy study revealed intervals reflecting warm surface waters and low-oxygen conditions on the seafloor, associated with the orbitally driven presence of Early Pliocene rhythmic sapropelic layers. Between ∼5.2 and 4.6 Ma, the sapropelic layers were characterized by elevated abundance of Reticulofenestra spp. and Florisphaera profunda, depicting increased productivity throughout the photic zone. Both enhanced riverine inputs and weak presence of Levantine Intermediate Water (LIW) characterized this time interval. The alterations in the calcareous nannofossil patterns with increased Helicosphaera spp. and Umbilicosphaera jafari abundances, implying freshening and enhanced mid-photic productivity after ∼4.6 Ma, suggest strengthening of LIW intrusion combined with the full restoration of North-South Aegean marine gateways that led to the establishment of a hydrographic system similar to the modern Aegean Sea.

Giant offshore pumice deposit records a shallow submarine explosive eruption of ancestral Santorini

Large explosive volcanic eruptions from island arcs pour pyroclastic currents into marine basins, impacting ecosystems and generating tsunamis that threaten coastal communities and infrastructures. Risk assessments require robust records of such highly hazardous events, which is challenging as most of the products lie buried under the sea. Here we report the discovery by IODP Expedition 398 of a giant rhyolitic pumice deposit emplaced 520 ± 10 ky ago at water depths of 200 to 1000 m during a high-intensity, shallow submarine eruption of ancestral Santorini Volcano. Pyroclastic currents discharged into the sea transformed into turbidity currents and slurries, forming a >89 ± 8 km3 volcaniclastic megaturbidite up to 150 m thick in the surrounding marine basins, while breaching of the sea surface by the eruption column laid down veneers of ignimbrite on three islands. The eruption is one of the largest recorded on the South Aegean Volcanic Arc, and highlights the hazards from submarine explosive eruptions.

DEVELOPMENT STATUS of RURAL NEIGHBORHOODS in THE SOUTH AEGEAN REGION in THE CONTEXT of RURAL DEVELOPMENT

In many countries today, rural development has become a priority for governments. Rural development refers to a process that envisages the development of societies not only economically but also socially and culturally. Rural areas often harbor a population that does not have sufficient income, has limited basic infrastructure facilities and opportunities, is generally engaged in agriculture or agriculture-based work as an economic activity, and has limited opportunities in education and health services. Despite all the investments and efforts made since 1923 for the development of rural communities, the large number and scattered nature of rural settlements, the difficulties experienced in transportation to these areas, and the wrong and inadequate decisions taken for these areas have led to the failure to reach the desired level for the development of these areas as a whole in Turkey, which is in the process of development.
 Within the scope of this study, the current level of rural development in all rural settlements in the South Aegean Region, which is among the developed regions of Turkey, and what local people see as the most important problem in the lack of rural development have been investigated. This quantitative research, which is specific to the South Aegean Region and covers all rural settlements, is important in that it emphasizes the social dimension of rural development and makes a unique contribution to subsequent rural development-oriented studies.

Towards an Integrated and Accurate Planktonic-Foraminiferal-Deduced Bio-Chrono-Stratigraphic Framework of Late Quaternary Mediterranean Marine Cores

The late Quaternary is a key stratigraphic interval as it encompasses the Late Glacial to Holocene transition, which is characterized by a series of pronounced centennial climate oscillations and subsequent short-term events of paleoceanographic variability. Across this stratigraphic interval, significant turnovers and faunal changes in the composition and abundance of planktonic foraminiferal assemblages are well-documented through their high-resolution quantitative analysis performed in the south Aegean core NS-18. The identification of 10 synchronous bioevents among the Mediterranean sub-basins allows accurate inter-basinal correlations over the study time interval, thus contributing to the development of a robust chronostratigraphic framework for this setting. Moreover, the identification and timing of additional 20 diachronous bioevents, in conjunction with the already established bio-ecozonation scheme of the Aegean Sea, provide a continuous record of faunal changes (in terms of species-specific distributional abundances) which can be used as an additional locally expressed biochronological tool for the eastern Mediterranean deep-sea cores. The present study certainly indicates that the cause-and-effect relationships between the paleoceanographic/paleoclimatic perturbations and biological response require a highly resolved regional chronostratigraphy.

How gradients of climate and soil determine Mediterranean annual‐rich dryland vegetation

AbstractQuestionsDryland annual plant communities constitute the most species‐rich small‐scale vegetation in the Mediterranean. Nevertheless, the composition and diversity of these units and the factors controlling their variation are still insufficiently understood. Therefore, we investigated species composition and richness patterns in relation to important environmental gradients provided by climate and soil.LocationCentral Crete, Greece.MethodsThe study is based on 82 plots of 4 m2 sampled at altitudes between 11 and 1400 m a.s.l. We conducted vegetation relevés and soil analyses. We used generalised additive models to model species richness and community characteristics along the studied gradients. We then performed distance‐based redundancy analysis to determine the main environmental factors influencing species composition. To determine species of diagnostic value for bedrock types, we applied an indicator species analysis. Correlation tests were used to test the performance of the South Aegean Plant Indicator Values on our dataset.ResultsWe recorded 347 taxa (species and subspecies) of 43 plant families, and mean species numbers of 47.2 ± 12.5 per plot. While overall species richness varied only slightly along the analysed environmental gradients, significant changes were observed for relative proportions of species from different life forms and families. Soil pH and elevation had the highest influence on the variation in species composition (21.0% explained). We found 22 species indicative of calcareous rock and 24 species indicative of lime‐deficient rock types. The South Aegean Plant Indicator Values were relatively strongly correlated with environmental variables.ConclusionsResults indicate considerable species turnover both along climatic (elevation) and soil gradients, highlighting the special importance of soil pH. The data provided by our study are expected to supply relevant ecological background information for a pending classification of East Mediterranean annual‐rich vegetation.

Petrological and geochemical evidence for a hot crystallization path and a recharge filtering bypass at Antimilos, Milos volcanic field, Greece

Antimilos volcano in the South Aegean Volcanic Arc, Greece, comprises an andesite–dacite suite that follows a distinct evolutionary path than the main edifice of the Milos volcanic field, despite their proximity. Petrographic and geochemical analyses reveal that basaltic andesite to low-Si dacite lavas have similar phenocryst assemblages that indicate crystallization from hot, relatively dry magmas in an upper crustal storage region. Rare antecrystic high-Mg# clinopyroxene cores with low Y, low Dy, and high Sr contents record the cryptic involvement of amphibole, a phase nominally absent from the erupted products, in the deeper parts of the plumbing system. Low temperature antecrysts with textures recording various degrees of disequilibrium suggest a protracted history of interaction between the upper crustal reservoir and deeper mafic melts, forming mobile hybrid magmas that consequently erupt as highly mingled, crystal-rich lava domes. Antimilos magmas seem to have escaped recharge filtering in the upper crust and prolonged stalling, which is the process that is probably responsible for the paucity of mafic eruptions in the rest of the Milos volcanic system. Large extensional structures offshore of Antimilos promote rapid ascent of mafic melts, inhibiting prolonged stalling and interaction with the arc crust. This model highlights the dominant role of the regional stress field in generating petrologically distinct suites in the marginal parts of some volcanic fields.

A 3D BEM Model for the Hydrodynamic Analysis and Design of Heaving WEC Arrays Attached to a Breakwater

Assessment of the performance of arrays of wave energy converters (WECs) of the type of simple heaving floaters, operating in nearshore and coastal areas, is essential to estimate their power production capacity. The effective design and layout of such WEC farms can be supported by studying the system’s operational characteristics based on the wave climatology of the deployment region. Installation along the exposed side of harbor breakwaters in sea areas with substantial incoming energy potential is a promising option. In this study, a 3D hydrodynamic model based on the boundary element method (BEM) is presented and discussed, aiming to evaluate the performance of WEC arrays consisting of multiple heaving bodies attached to the exposed side of a harbor breakwater, modelled as a vertical wall, considering its reflective effects, as well as hydrodynamic interactions between the multiple floating devices. Numerical results of the predicted power performance for various configurations, including interactions of multiple WECs with the nearshore topography and the breakwater wall, as well as the effects of power take off (PTO) parameters, are presented and discussed. Finally, a case study is presented for a selected coastal site at the port of Heraklion, located in the north-central part of Crete Island in the South Aegean Sea, characterized by relatively increased wave energy potential, using long-term climatological data, illustrating the method and its applicability as a supporting tool for optimal design of WEC arrangements.

Analysis of Burnout, Job Satisfaction, and Fatigue Among Yacht Crew: A Case Study of Turkish Yacht Crew Operating in the Southern Aegean Sea

An examination was conducted on the correlation between burnout, job satisfaction, fatigue levels, and the demographic characteristics of yacht crew. In March 2023, a survey was administered to 81 yacht crew of various ratings operating in the South Aegean. The Maslach Burnout Inventory, Minnesota Satisfaction Questionnaire, and Piper Fatigue Scale were used in the study, and the subdimensions of these scales analyzed in detail in relation to the yacht crew. Low burnout levels, moderate emotional exhaustion, low depersonalization and a lack of personal accomplishment was found among participants. Job satisfaction was moderate, primarily influenced by internal factors. Overall fatigue levels were moderate, with varying subscale levels. Deckhands had higher burnout and fatigue levels, whereas able seamen had the highest job satisfaction. Statistically significant relationships were found between participant age and years of service and burnout; between job satisfaction, competence, and years of service; and between fatigue and marital status. A statistically significant relationship was found between crew burnout and their levels of job satisfaction and fatigue. Another finding of the research was that males had higher job satisfaction than females, however, male crew members reported higher levels of burnout and fatigue. Furthermore, since there is dense yacht traffic in the Aegean Sea, the high levels of fatigue among yacht crew in the region could be affecting the safety of commercial vessel navigation. Excluding captains, this study is the first to research job satisfaction, burnout, and fatigue levels among yacht crew.

A comparative study on training systems and vine density in Santorini Island: Physiological, microclimate, yield and quality attributes

The Mediterranean basin is regarded as one of the most affected global regions by climate change. Traditionally, viticulture in this region copes with high temperatures, heat waves and drought. Such extreme conditions are expected to intensify due to climate change in the future. Our study focuses on the viticulture of Santorini Island, located in South Aegean (Greece). Local varieties trained with the traditional ‘Kouloura’ training system have been cultivated for thousands of years on the island, producing recognised high-quality PDO wines worldwide. The literature on these traditional training systems is scarce, and their investigation could aid in the adaptation of viticulture to hotter and drier future climatic conditions. The objective of this study was to compare the physiological and agronomic response of Assyrtiko grapevines to the traditional training systems ‘Kouloura’ and VSP training system over two growing seasons and to establish the factors influencing the performance of each system in the semi-arid conditions of Santorini Island. In brief, the ‘Kouloura’ training system maintained a less-stressed water status compared to VSP, while for both studied years during ‘Kouloura’ exhibited significantly higher photosynthetic rates and stomatal conductance. Regarding microclimate observations, we found that, especially during heatwaves, VSP’s grapes were more exposed to higher temperatures during midday than ‘Kouloura’ and that the ‘Kouloura’ system protected against damage from heatwaves and strong winds when compared to VSP. Investigating the mechanisms by which these traditional training systems are adapted to hot, dry climatic conditions creates applicable knowledge for developing and using alternative training systems in similar environments to adapt to climate change.

Short-beaked common dolphins of Dilek Peninsula National Park, South Aegean Sea: Preliminary results on group structure, spatial distribution, behavioural patterns, whistle characteristics and behavioural context

Basic knowledge about populations of short‐beaked common dolphins (Delphinus delphis) in the eastern part of the Mediterranean Sea is still lacking. Classified as ‘Endangered’ in an IUCN assessment released in 2022, it is necessary to gain baseline knowledge to understand the species’ population status and develop impactful conservation measures. The current study conducted boat surveys, employing visual and acoustic techniques between January 2019 and July 2022 in the Dilek Peninsula National Park, central Aegean Sea. Results revealed the continuous coastal presence of common dolphins, with subadults recorded during every sighting in low group sizes. Travelling‐related activities made up 58% of observed behaviour while resting comprised just 1%. Whistles were produced in the range of 1.83–48kHz with a peak frequency of 10.4kHz and median duration of 0.54s. Concave whistles were the most frequently recorded whistle type. Whistles were found to be generated when dolphins were interacting with boats and diving/travelling fast, forming 53% and 31% of whistle production respectively. The continuous presence of common dolphins, particularly subadults, emphasises the importance of the Dilek Peninsula. Whistle parameters show similarities with other common dolphin populations of the Mediterranean and Black Sea, albeit with shorter durations. The high whistle presence during boat interactions requires investigation to assess whether whistles carry avoidance or predatory messages, or whether there are potential consequences for the species’ energy budget. The current study presents preliminary information on the behavioural context of acoustic patterns. Further research is essential to understand the click and whistle characteristics within the biological, environmental and anthropogenic variables of their surroundings.

Saint Mamas at Exeles: An Unusual Case of Ritual Piety on Karpathos

The church of Saint Mamas is a small, domed structure that lies close to Menetes village in Karpathos. It preserves most of its painted decoration, consisting of the scene of the Ascension of Christ on the dome and saintly figures on the rest of the surfaces. A dedicatory inscription, read here for the first time, dates the frescoes to 1312/3 and places them in the broader context of precisely dated monuments. Certain features of the iconographic program, such as the presence of healer saints (Panteleemon and Kyprianos) but mostly of the officiating Pope Sylvester and the passage used in the codex of Christ Pantocrator on the apse of the altar, lead us to interesting conclusions concerning, among other things, the perception of anti-Latin propaganda in the islands of the South Aegean. Also, the stylistic affinities between the art of Karpathos and Crete corroborate the diachronic interrelations between the two islands. The church of Saint Mamas is an exceptional example and one of the few Byzantine-decorated monuments that survive on the island.

Macro- and microplastic abundance from recreational beaches along the South Aegean Sea (Türkiye)

This study aimed to evaluate the abundance and diversity of macro- and microplastics in sand samples collected during summer and winter from eight different beaches used for recreational purposes located on the South Aegean coasts of Türkiye. According to the results, microplastic in fiber shape was dominant on all the beaches. The highest microplastic abundance was determined at Ölüdeniz Kumburnu Beach (360.00 ± 237.66 particles kg−1 dw) in summer and at Aktur Beach (358.33 ± 397.24 particles kg−1 dw) in winter. A significant positive correlation was found in the winter between microplastic amounts and wind speed. The study area is an important touristic center faraway from major cities and industrial areas. Thus, plastic pollution in this area may be the result of tourism activities in the summer, discharge waters from wastewater treatment plants or transportation by meteorological factors (like waves, wind or river flows).

Refugee Representations by the Greek Public Administration: A Critical Review of the Greek Institutional Discourse

This paper examines the political narratives employed in strategic communication between Greek authorities and the public administration during the refugee flows of 2015-2018. It also looks into the formation of images concerning refugees within the Greek political context and contributes to the existing literature on discursive representations of refugees. The study delves into the role of political rhetoric in strategic or non-strategic image formation, thus revealing the other side of media representations. It focuses on an overlooked aspect of political communication: the discourse of public administration institutions. The methodology uses qualitative content analysis with elements of discourse analysis, focusing on press releases from public administration institutions involved in the refugee crisis, as well as a selected corpus of public speeches from government members and local authorities. The institutions examined include the Ministry of Migration Policy, the Regional Administration of North Aegean, and the Regional Administration of South Aegean. The research covers the period from January 2015 to April 2018, encompassing a total of 159 press releases issued by the authorities under study regarding the refugee situation.