Search Results (186)

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

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

The barrel jellyfish (Rhizostoma pulmo), like other cnidarians, shows cnidocytes containing cnidae, responsible for the jellyfish’s stinging properties. The sting of R. pulmo can cause contact dermatitis or urticaria and even systemic symptoms. Recent studies have identified stinging-cell structures in the mucous secretion released in the water column by Cassiopea xamachana, belonging to the same order as R. pulmo. The present paper verifies the release of stinging-cell structures in the water by R. pulmo and reports the case of two 17-year-old adolescents (one male and one female) who were affected by epidermal rashes consistent with the irritating sensations of stinging water. The reaction happened twice in the Ionian Sea; the patients were in proximity to R. pulmo but, on both occasions, there had been absolutely no direct contact with the jellyfish’s tentacles. To test the hypothesis of stinging water caused by R. pulmo, samples of sea water and mucous harvested in close proximity to a living jellyfish were taken and analyzed under a microscope at different magnifications. The microscopic analysis showed the presence of free and aggregated nematocysts in both the samples of water and mucous. It is likely that the free and aggregated nematocysts observed were discharged in the water by the jellyfish and were dispersed by water currents that led them to come into contact with the patients’ skin. At present, it is not known what predisposes humans to the perception of stinging water, and it is reasonable to affirm that caution should be advised for people with an allergic history when entering the water in the presence of jellyfish. Further investigations are required to better understand both the pathophysiological pathways underlying the stinging water phenomenon and the minimum concentration of urticating elements that is able to trigger the onset of stinging water. 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

Microalgae are a subject of interest not only for fundamental research but for various biotechnological applications as well. In this study, the ability of newly isolated strains, i.e., Picochlorum costavermella VAS2.5, Picochlorum oklahomense SAG4.4, Microchloropsis gaditana VON5.3, and Nephroselmis pyriformis PAT2.7, to grow when cultured in an open raceway pond under laboratory conditions and produce various metabolites of high-added value was evaluated. N. pyriformis PAT2.7 and P. costavermella VAS2.5 were the greatest in biomass production (exceeding 0.4 g/L), while P. costavermella VAS2.5 and M. gaditana VON5.3 were the greatest in lipid production (reaching approximately 18%, wt/wt). The lipid fraction of glycolipids and sphingolipids was predominant (43.6–55.4%, wt/wt), followed by neutral lipids (27.1–50.1%, wt/wt) and phospholipids (6.9–17.4%, wt/wt). Picochlora and M. gaditana VON5.3 lipids were rich in ^{Δ5,8,11,14,17}C20:5 and/or ^Δ9,12,15C18:3, while N. pyriformis PAT2.7 synthesized ^Δ9C16:1 in large quantities (30–40%, wt/wt). All strains showed remarkable yields in polysaccharide and protein production, demonstrated a well-balanced amino acid profile, and synthesized pigments in amounts comparable to other studies. The biochemical profiles of these strains showcased their suitability for use primarily in the aquaculture sector. Full article

Understanding the trophic interactions and community structure of zooplankton is essential for assessing energy transfer in marine ecosystems. This study investigates the spatial and seasonal variations in stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotopes of dominant mesozooplankton groups across three sub-basins of the Eastern Mediterranean (North Aegean, Cretan, and South Ionian Seas) during two seasonal surveys (October 2014 and May 2015). Zooplankton samples were collected using a WP-2 net and analyzed for taxonomic composition, abundance, biomass, and stable isotopic signatures to assess trophic positioning. The results indicate that copepods dominated the zooplankton community at all stations, with Clausocalanus and Oithona juveniles being the most abundant taxa. Salps contributed significantly at certain stations, reflecting regional variations in the planktonic food web structure. Zooplankton δ¹⁵N values exhibited pronounced spatial and seasonal differences, with higher enrichment observed in 2014 compared to 2015. The calculated trophic positions highlight the variability in feeding strategies among copepod species, with Calanus helgolandicus occupying the highest trophic position (TP = 3.34) and Lucicutia spp. the lowest (TP = 1.22). Isotopic niche analysis identified two distinct feeding guilds: a group relying on phytoplankton and microzooplankton and another exhibiting broader trophic plasticity, including omnivorous and carnivorous taxa. These findings underscore the complexity of zooplankton trophic interactions in the Eastern Mediterranean and the role of regional hydrographic conditions in shaping the food web structure. This study provides essential baseline data for future research on the impacts of climate change and nutrient variability on Mediterranean marine ecosystems. Full article

In an effort to monitor ascidian recruitment in mussel aquaculture facilities, a series of settlement plates (20 × 20 cm) were placed in a mussel farm located in the Amvrakikos Gulf (Ionian Sea). The plates were vertically deployed on floating facilities in the water column at regular intervals (depths of 0.2 m, 1.5 m, and 3 m) to monitor the settlement and proliferation of ascidians. Furthermore, measurements of seawater physicochemical parameters such as temperature, salinity, dissolved oxygen, and chlorophyll-a concentration were conducted together with the record of ascidian species in each sampling from January 2021 to November 2021. The correlation of these parameters with ascidian species provides information on their effect on the periodicity of ascidians’ recruitment. The results demonstrated a significant correlation between ascidian presence and water temperature. The potential influence of other important environmental parameters such as chlorophyll-a was not revealed, likely due to the limited number of values and samples included in the analyses. While increased chlorophyll levels, reflecting increased primary productivity or nutrient availability, are associated with increased growth and reproduction of all ascidian species, the effect of temperature was more potent and species-specific. Ciona robusta, Styela plicata, Microcosmus squamiger, and Phallusia mammillata were mainly detected at temperatures below 25 °C, whereas Clavelina oblonga was prevalent at temperatures above 25 °C. The absence of most ascidians at temperatures above 25 °C was possibly attributed to decreased settlement success and to the increased competition from C. oblonga at higher temperatures. The deployment of settlement plates in correlation with seawater physiochemical parameters can provide valuable data on ascidian settlement dynamics and support the development of targeted management practices for biofouling control. Full article

Textile-reinforced alkali-activated mortar (TRAAM) is a composite material that is characterized by a strain- or deflection-hardening response under tension or flexure, respectively, as well as by a good bond with concrete and masonry substrates. Owing to comparable or even superior mechanical performance compared to “conventional” cement- or lime-based textile-reinforced mortar (TRM) systems and its potentially eco-friendly energy and environmental performance, TRAAM has been incorporated to retrofitting schemes. The current article reviews the studies that investigate TRAAM as a strengthening overlay for masonry and concrete members. This article focuses on the mechanical performance of the strengthened members, which, where possible, is also compared with that of members strengthened with conventional TRM systems. It is concluded that TRAAM can enhance the flexural and shear capacity of masonry and concrete members, while it can also upgrade the compression strength and seismic response of concrete members. In addition, it is concluded that the effectiveness of TRAAM can be comparable with that of “conventional” TRM systems. The combination of TRAAM with thermal insulation boards has also been proposed for structural and energy upgrading of masonry walls. Furthermore, TRAAM can be a promising solution for increasing the fire resistance of strengthened masonry members. However, research on the long-term performance of TRAAM, including durability, creep, and shrinkage, is still limited. Finally, the lack of established standards for TRM retrofitting is more evident for TRAAM applications. Full article

Distributed Acoustic Sensing (DAS) technology presents an innovative method for marine monitoring by adapting existing underwater optical fiber networks. This paper examines the use of DAS with the Istituto Nazionale di Fisica Nucleare–Laboratori Nazionali del Sud (INFN-LNS) optical fiber infrastructure in the Gulf of Catania, Eastern Sicily, Italy. This region in the Western Ionian Sea provides a unique natural laboratory due to its tectonic and volcanic activity, proximity to Mount Etna, diverse marine ecosystems and significant human influence through maritime traffic. By connecting a 28 km long optical cable to an Alcatel Submarine Network OptoDAS interrogator, DAS successfully detected a range of natural and human–made signals, including a magnitude 3.5 ML earthquake recorded on 14 November 2023, and acoustic signatures from vessel noise. The earthquake–induced Power Spectral Density (PSD) increased to up to 30 dB above background levels in the 1–15 Hz frequency range, while vessel noise exhibited PSD peaks between 30 and 60 Hz with increases of up to 5 dB. These observations offered a detailed spatial and temporal resolution for monitoring seismic wave propagation and vessel acoustic noise. The results underscore DAS’s capability as a robust tool for the continuous monitoring of the rich underwater environments in the Gulf of Catania. Full article

The observed scaling properties in the three aftershock sequences of the recent strong earthquakes of magnitudes M_w 6.1, M_w 6.4 and M_w 6.7, which occurred in the Ionian island region on the 26 January 2014 (onshore Cephalonia Island), 17 November 2015 (Lefkada Island) and 25 October 2018 (offshore Zakynthos Island), respectively, are presented. In the analysis, the frequency–magnitude distributions in terms of the Gutenberg–Richter scaling relationship are studied, along with the temporal evolution of the aftershock sequences, as described by the Omori–Utsu formula. The processing of interevent times distribution, based on non-extensive statistical physics, indicates a system in an anomalous equilibrium with long-range interactions and a cross over behavior from anomalous to normal statistical mechanics for greater interevent times. A discussion of this cross over behavior is given for all aftershock sequences in terms of superstatistics. Moreover, the common value of the Tsallis entropic parameter that was obtained suggests that aftershock sequences are systems with very low degrees of freedom. Finally, a scaling of the migration of the aftershock zones as a function of the logarithm of time is discussed regarding the rate strengthening rheology that governs the evolution of the afterslip process. Our results contribute to the understanding of the spatiotemporal evolution of aftershocks using a first principles approach based on non extensive statistical physics suggesting that this view could describe the process within a universal view. Full article

From August 2021 to December 2023, one adult male Mediterranean monk seal was repeatedly registered, through a systematic monitoring camera system, frequenting a marine cave in southern Kefalonia Island, central Ionian Sea, Greece. The presence of the same adult seal in a series of caves and overhangs in a bay in northwestern Zakynthos, southern Ionian Sea, in September 2023 and May 2024 was verified through opportunistic surveys and citizen science. The two locations are ca. 15 km apart and each is located in a different marine NATURA 2000 site. Appropriate conservation measures need to take into consideration the fact that seals do move between Kefalonia and Zakynthos (and possibly also other Ionian islands) and that the entire area has to be considered as a single “conservation unit” rather than elaborating protection measures on a small scale around a couple of resting and pupping caves alone. A full network of marine caves under strict protection surrounded by a buffer zone, taking into account at least the species’ home range, is needed in order to substantially cover the monk seal’s critical terrestrial habitats throughout the Ionian Sea. Full article

The central Ionian Sea is one of the most seismogenic areas in the Mediterranean Sea region. In particular, the island of Lefkada, Greece, has experienced many catastrophic earthquakes. The historical seismicity of Lefkada has been revised by utilizing published and little-known macroseismic information sources, e.g., administrative documents, letters, marginal notes, and eyewitness accounts. We organized a new descriptive and parametric catalogue of 44 earthquakes that had their maximum macroseismic intensity in Lefkada and covered the time interval from the 15th century A.D. up to 1911. Earthquake dates, origin times, intensities, magnitudes, and epicentral coordinates were estimated or revised. Magnitudes estimated in previous catalogues in general are larger with respect to our magnitude determinations, possibly due to different calculation methods. The descriptive part of the catalogue includes descriptions of the earthquakes’ impact on buildings and of environmental effects, e.g., landslides and local tsunamis. The catalogue completeness gradually increases with time but is likely complete for the entire period examined lower magnitude threshold M_w = 6.0. One important yet puzzling earthquake is the large one that reportedly ruptured the Strait of Otranto and damaged an unprecedentedly extensive region in Italy, Albania, and Greece, including Lefkada, on 9/20 February 1743. Little-known documents revealed that the heavy destruction supposedly caused in Lefkada was very likely due to amalgamated information regarding local earthquakes and the large one. Full article

Sulfur dioxide (SO₂) can be of natural and anthropogenic origin and is one of the sulfur compounds present in the atmosphere. Among natural sources, volcanoes contribute with relevant annual outputs, and major eruptions lead to spikes in these outputs. In the case of anthropogenic pollution, SO₂ emissions are mostly correlated with the sulfur content of fuels, which has been the focus of specific emission mitigation policies for decades. Following other examples of cyclic and multi-year evaluations, an analysis of SO₂ at the Lamezia Terme (code: LMT) WMO/GAW (World Meteorological Organization—Global Atmosphere Watch) station in Calabria, Southern Italy, was performed. The coastal site is characterized by wind circulation patterns that result in the detection of air masses with low or enhanced anthropic influences. The presence of the Aeolian Arc of active, quiescent, and extinct volcanoes, as well as Mount Etna in Sicily, may influence LMT observations with diffused SO₂ emissions. For the first time in the history of the LMT, a multi-year analysis of a parameter has been integrated with TROPOMI data gathered by Sentinel-5P and used to test total tropospheric column densities at the LMT itself and select coordinates in the Tyrrhenian and Ionian seas. Surface and satellite data indicate that SO₂ peaks at the LMT are generally linked to winds from the western–seaside wind corridor, a pattern that is compatible with active volcanism in the Tyrrhenian Sea and maritime shipping to and from the Gioia Tauro port located in the same region. The findings of this research provide the basis for enhanced source apportionment, which could further differentiate anthropogenic sources in the area from natural outputs. Full article

This study investigates the effects on hard-bottom macro-zoobenthic communities of converting a mariculture plant into an Integrated Multi-Trophic Aquaculture (IMTA) system. This study was conducted from 2018 to 2021 in the semi-enclosed Mar Grande basin of Taranto (northern Ionian Sea), on a facility located 600 m off the coastline, with a production capacity of 100 tons per year of seabass (Dicentrarchus labrax) and seabream (Sparus aurata). The results from seasonal sampling performed in a treatment site, where bioremediators (filter-feeding invertebrates such as sponges, polychaetes, mussels, and macroalgae) were deployed, and a control site without bioremediators were compared. Before the IMTA installation, the hard substrates under the cages were sparsely inhabited, with significant sediment coverage. By 2021, the treatment site exhibited revitalized and more diverse macro-zoobenthic communities, with species richness increasing from 83 taxa in 2018 to 104 taxa, including notable growth in sponges, annelids, mollusks, and bryozoans. In contrast, the control site showed no substantial changes in biodiversity over the same period. Biodiversity indices, including Shannon and Margalef indices, improved significantly at the treatment site, particularly during summer months, highlighting a more resilient and balanced benthic environment. Taxonomic distinctness (delta+) and multivariate analyses (PERMANOVA, PCO) confirmed significant spatial and temporal shifts in community structure at the treatment site, driven by IMTA implementation. SIMPER analysis identified key taxa contributing to these changes, which played a pivotal role in structuring the community. The emergence of filter feeders, predators, and omnivores at the treatment site suggests enhanced nutrient cycling and trophic complexity, while the decline in opportunistic species further supports improved environmental conditions. These findings demonstrate the potential of IMTA to promote recovery and sustainable mariculture practices, also offering a comprehensive understanding of its positive effects on hard-bottom benthic community dynamics. Full article

Marine ecosystems are increasingly threatened by pollutants, including trace elements (TEs) such as heavy metals, which bioaccumulate and pose risks to both marine fauna and human health. Sharks and rays are particularly susceptible to metal uptake and retention, making them sentinel species for assessing environmental contamination. This study investigated the bioaccumulation of 16 TEs across 12 elasmobranch species sampled from the Ionian and Tyrrhenian coasts of Calabria, southern Italy, over an 11-year period. Muscle tissue was analyzed for all species, while additional comparisons among skin, muscle, and brain tissues were conducted for Galeus melastomus. Statistical analyses revealed significant variability in TEs concentrations across trophic levels (TRLs), with higher levels observed in species occupying higher trophic positions. Positive correlations were noted for elements such as Al, Ba, and Se, while negative correlations were found for Co, Cu, Mn, and U, indicating species-specific metabolic adaptations. Tissue-specific analyses identified the skin as a primary site for TEs accumulation, likely due to its barrier functions and external exposure. This study highlights the complex interplay of ecological, dietary, and physiological factors influencing TEs bioaccumulation in elasmobranchs and emphasizes the need for further research to understand the implications for marine food webs and conservation strategies. Full article