Eastern Coast Of Sicily Research Articles

Ecology and Phenology of the Subtidal Brown Alga Sargassum furcatum (Ochrophyta, Fucales), a Likely Non-Indigenous Species from the Mediterranean Sea

This study provides new insights regarding the ecology and phenology of the likely non-indigenous canopy-forming species Sargassum furcatum on the central-eastern coast of Sicily (Italy, Central Mediterranean). This species was described for St. Thomas (Virgin Islands), and it was reported for the first time in the Mediterranean in 1995 in the Chafarinas islands (Spain, western Mediterranean). After the first report, this species was found in 2021 in several sites located along the eastern coast of Sicily (Italy), along the French Mediterranean coastline, in Corsica, and recently also in the Aeolian Islands (Italy). No phenological studies on this species have been ever carried out in the Mediterranean Sea. To conduct this study, a visual census activity was performed in three sites along the Ionian coast of Sicily throughout 2023, during which the length of the main axis of S. furcatum specimens was measured and the frequency of findings of the species during the year was noted. In this study, it was observed that S. furcatum shows a wide adaptability in terms of range of depth, temperature, light exposure, and type of substrate. Since the distribution of this species is mostly centralized in the western Atlantic Ocean, it is likely that S. furcatum entered the Mediterranean through the Gibraltar Strait. Consequently, the entrance of this species in this Basin could be further proof of the ongoing seawater warming and tropicalization of Mediterranean waters. From this point of view, it is important to keep monitoring the dynamics of S. furcatum in the Mediterranean Sea in order to understand its putative impacts on autochthonous communities.

A heuristic features selection approach for scenario analysis in a regional seismic probabilistic tsunami hazard assessment

Seismic Probabilistic Tsunami Hazard Analysis (SPTHA) is aimed at estimating the annual rate of exceedance of an earthquake-induced tsunami wave of a certain location with reference to a predefined height threshold. The analysis relies on computationally demanding numerical simulations of seismic-induced tsunami wave generation and propagation. A large number of scenarios needs to be simulated to account for uncertainties. However, the exceedance of tsunami wave threshold height is a rare event so that most of the simulated scenarios bring little statistical contribution to the estimation of the annual rate yet increasing the computational burden. To efficiently address this issue, we propose a wrapper-based heuristic approach to select the set of most relevant features of the seismic model, for deciding a priori the seismic scenarios to be simulated. The proposed approach is based on a Multi-Objective Differential Evolution Algorithm (MODEA) and is developed with reference to a case study whose objective is calculating the annual rate of threshold exceedance of the height of tsunami waves caused by subduction earthquakes that might be generated on a section of the Hellenic Arc, and propagated to a set of target sites: Siracusa, on the eastern coast of Sicily, Crotone, on the southern coast of Calabria, and Santa Maria di Leuca, on the southern coast of Puglia. The results show that, in all cases, the proposed approach allows a reduction of 95% of the number of scenarios with half of the features to be considered, and with no appreciable loss of accuracy.

The nudibranchs (Gastropoda Heterobranchia) of the central- eastern coast of Sicily, II: Suborder Doridina

The nudibranchs (Gastropoda Heterobranchia) of the central- eastern coast of Sicily, II: Suborder Doridina

Eruption cycles of Mount Etna triggered by seasonal climatic rainfall

The ability to mitigate and predict volcanic risk is a long-standing question in the Geosciences’ community, while the extent of volcanic activity may be regulated by a predictable and periodic external excitation induced by seasonal rainfall, hydrological loading, or Moon-Sun gravitational force. Moreover, the complex stress-triggering, hydro-mechanical coupling in response to seasonal rainfall, and associated feedback mechanism with deep magmatic process remains enigmatic and indeed deserves more attention in view of recent climate change scenario. In this letter, a compelling scenario of seasonal rainfall-triggered eruption cycles of Mount Etna (Italy) is found and presented on the eastern coast of Sicily which continuously erupting since last 200 kyr. Results show that the seasonal rainfall significantly weakened the Mount Etna edifice and initiated mechanical tensile failure in the complex magmatic plumbing system and adjacent flank surface by changing the pore pressure build-up, probably promoting dyke intrusion and eventual triggering of eruptive cycle. Further, the possibility of seasonal hydrological loading on the Mount Etna volcano and adjacent flank region, hydrological load-induced sliding along the impermeable outer ‘shell’ of the flank are discussed, and the effect of tidal stress perturbations on the eruptions cycle cannot be ruled out completely.

Status of shallow Fucales (Ochrophyta) assemblages in the bay of Brucoli, eastern coast of Sicily (Ionian Sea)

Status of shallow Fucales (Ochrophyta) assemblages in the bay of Brucoli, eastern coast of Sicily (Ionian Sea)

The nudibranchs (Gastropoda Heterobranchia) of the central- eastern coast of Sicily I: Suborder Cladobranchia

The nudibranchs (Gastropoda Heterobranchia) of the central- eastern coast of Sicily I: Suborder Cladobranchia

Contribution to the knowledge of Pleurobranchus testudinarius Cantraine,1835 (Gastropoda Pleurobranchida) along the central- eastern coast of Sicily (Ionian Sea)

Contribution to the knowledge of Pleurobranchus testudinarius Cantraine,1835 (Gastropoda Pleurobranchida) along the central- eastern coast of Sicily (Ionian Sea)

The sacoglossans (Gastropoda Heterobranchia) of the central- eastern coast of Sicily (Ionian Sea)

The sacoglossans (Gastropoda Heterobranchia) of the central- eastern coast of Sicily (Ionian Sea)

Biodegradation Potential of Oil-degrading Bacteria Related to the Genus Thalassospira Isolated from Polluted Coastal Area in Mediterranean Sea

ABSTRACT Three bacterial species related to the genus Thalassospira (T. lucentensis, T. xianhensis and T. profundimaris), isolated from polluted sediment and seawater samples collected from Priolo Bay (eastern coast of Sicily, Ionian Sea), were analyzed for their biotechnological potential. For this purpose, the presence of specific catabolic genes associated to aliphatic and aromatic hydrocarbon metabolism, the production of biosurfactants and emulsification activity, the capability to degrade oil-derived linear, branched, cyclic alkanes, and polycyclic aromatic hydrocarbons (PAHs) were evaluated. Alkane hydroxylase gene (alkano-monoxygenase alkb and citocrome P450) were present in genome of all strains, confirming their hydrocarbons degrading capability. All strains of Thalassospira produced biosurfactants and showed emulsification activity. The two-dimensional gas chromatography analysis (GC×GC) showed that they were able to degrade oil fractions with the capacity ranging between 77% and 91%. The data obtained in this study demonstrated the biodegradation ability of Thalassospira and suggest that these strains play an important role in marine contaminated ecosystems

Wintering shorebird in sandy coasts of Catania’s gulf (Sicily, Italy): 2011-2020

Sandy coasts are specific habitats of high ecological significance for many species of shorebirds. The Gulf of Catania, in the Eastern coast of Sicily, is considered one of the most important sandy coastal areas of the region for the wintering of different species of Charadriidae and Scolopacidae, also due to the presence of River Simeto’s mouth and other freshwater streams. Since the area has been subject to many changes in the last few decades and recent data were not available, a ten-year monitoring of the wintering shorebird community has been carried out, from January 2011 to January 2020, to understand its current ecological role and to update the knowledge about numbers and trends of Sicilian wintering shorebirds along the coast. A total of 3,171 individuals and 16 different species were observed, including a considerable amount of individuals of Calidris alba and Charadrius alexandrinus, despite the latter showed an 80% decrease in number in the last 20 years in the area. For each species, maximum numbers observed per winter and related five-year averages, estimates, IKA (Index of Abundance per Kilometre) and percentages in relation to the national wintering population have been reported. Furthermore, data about species associations were collected and analysed. This survey shows how the ecological value of River Simeto’s mouth has decreased considerably in the last decades in favour of other locations, such as the mouth of Canale Arci, where almost 50% of the birds were observed.

Lower Ionospheric Turbulence Variations During the Recent Activity of Etna’s Volcano, Sicily, in December 2018

In this paper, we present an investigation on the ionospheric turbulence from TEC observations before and during the recent activity of Etna’s Volcano. Mount Etna is located close to the eastern coast of Sicily. The last eruption of Etna volcano took place on 24 December 2018 while two days later (26 December, 02:19 UTC) an earthquake of M=5.0 occurred ~15 km to the ESE of the volcano, causing damage to the nearby city of Catania. The results of our investigation, on the occasion of the Etna’s Volcanic activity, indicate that the high-frequency limit fo of the ionospheric turbulence band content, is increasing with time to the volcano eruption while, at the same time, fo isdecreasing with distance from the volcano. We conclude that the LAIC mechanism through acoustic or gravity waves could explain this phenomenology, as it has happened in cases of earthquake activity. Our observations indicate that the effect of volcanic eruption on the band content of the ionospheric turbulence is insignificant at distances greater than 1000km (at the most), a fact that we must consider in our research on Ionospheric turbulence in relation to earthquake precursors research.

Degradation of a photophilic algal community and its associated fauna from eastern Sicily (Mediterranean Sea)

The status of the “Biocoenosis of the Infralittoral Algae” of the upper infralittoral zone (at 5 m depth) from two selected stations along the eastern coast of Sicily (Ionian Sea, Mediterranean) was studied with a multiproxy approach involving the study of algae and associated protist and animal organisms, including foraminifers, serpulids, molluscs, bryozoans and ostracods. Scraped samples (40x40 cm) were collected at selected seasons during a 2-year period (2015-2016) in order to identify possible seasonal and spatial differences between the two stations, and to compare present data with historical ones. A community made up of the algae Halopteris scoparia, Padina pavonica, Dictyota dichotoma, Ellisolandia elongata and several other geniculate coralline algae was found in sites historically colonised by a Cystoseira brachycarpa community, which was not found during our study. These algae presently structure the community and provide substratum for several associated epibiotic species. Hierarchical cluster analysis and Non-Metric Multi-Dimensional Scaling Ordination significantly differentiate the communities between the two stations but show no clear seasonal trend. Differences largely relate to changes in the algal vegetation and the impact produced by the regression of structuring species on epibiots (especially serpulids and bryozoans). Comparison with historical algal data from the area indicates the disappearance of Cystoseira brachycarpa, which was present at least until the last ’1990s, and a community degradation with a considerable loss in species richness. This parallels observations in other Mediterranean areas, and could be related to the increase in echinoid population density and their heavy grazing activity.

A COMBINED APPROACH FOR SURVEYING COMPLEX COASTAL SITES

Abstract. This study presents an integrated approach for reading coastal sites. A process aimed at protecting and enhancing these sites must be developed alongside a targeted interdisciplinary strategy, closely linked to the fields of archaeology, survey, landscape reading, morphology of the territory and geology. These must no longer be managed as individual cognitive elements, but within a single comprehensive analytical interpretation model.The experiment activity carried out along the rocky area of Aci Castello, on the eastern coast of Sicily, was developed using a methodological approach based on the integration of 3D data coming from various survey technologies – 3D laser scanning, mobile mapping and echo sounder systems. The aim of the experiment was to create a complete three-dimensional model of the studied area, focused on obtaining a dynamic understanding, that is punctual and comprehensive, of the site’s value and fragility.

Volcanic risk and the role of the media. A case study in the Etna area

On December 24, 2018, the Etna volcano has recorded a significant eruption. Linked to this phenomenon, after a seismic swarm of 72 shocks, a 4.8-magnitude earthquake struck a large area North of Catania city, on the Eastern coast of Sicily. Six villages reported 28 injured people and damages to the building. According to seismologists the earthquake had an unusual level of magnitude. Yet, despite the real danger of this event, many people who live around the volcano, in one of the most densely populated areas of Sicily, perceived these facts in an ambivalent way. Indeed, their lives continued as before even in awareness of the natural hazard, while several media presented the situation as really dangerous in a worried tone. This paper, part of a wider research still in progress, aims to analyse the perception of the risk towards the biggest and highest volcano of Europe by the inhabitants of some villages that rise around the Etna. Based on a previous research conducted in 2013 in the same area, this study compares the ways in which this recent earthquake was perceived by some residents in the area and the ways in which some online newspaper narrated the event. Therefore, by analysing and comparing the first results that come from interviews realized during a fieldwork and from online newspaper/magazine articles, this study tries to understand, from a geographical and cultural perspective, how the perception of the risk can be narrated attributing different values to hazard. The latter can have pragmatic implications because from this symbolic evaluation may depend the behaviour of an entire community.

STATIC AND DYNAMIC PROPERTIES OF SOILS IN CATANIA (ITALY)

The analysis of the historical reports and previous research projects allowed us to describe high-level seismic risk scenarios for the city of Catania, located on the eastern coast of Sicily (Italy). The geotechnical zonation of the subsoil of the city of Catania suggests a high seismic hazard added to a soil amplification of the ground motion. To this aim field and laboratory tests allowed the definition of a geotechnical characterisation in the city of Catania. For the site characterisation of soils deep site investigations have been undertaken. Borings and dynamic in situ tests have been performed in some selected test sites with the aim to evaluate the soil profiles of shear wave velocity and to retrieve undisturbed samples for laboratory tests. The testing programme consisted of standard classification tests, Oedometer tests, Direct shear tests, Resonant Column and Torsional shear tests. Two equations to draw the complete shear modulus degradation with strain level and the inverse variation of damping ratio with normalized shear modulus respectively have been also proposed. Shear wave velocity profiles experimentally obtained were compared with both in situ and laboratory tests.

Description and performance analysis of a flexible photovoltaic/thermal (PV/T) solar system

The main objectives of the present paper are to describe a pilot cogenerative PV/T plant and discuss its preliminary electrical and thermal experimental data. The PV/T plant is installed in the campus of the University of Catania, (Catania, Italy) on the eastern coast of Sicily, right in the centre of the Mediterranean area. The operative conditions of the experimental PV/T plant can be modified to implement parallel and series electrical and hydronic connections to the PV/T modules. The electrical and thermal load supplied by the PV/T plant can also be managed in order to simulate different energy demand scenarios. This study reports the main thermal and electrical operating parameters of the PV/T plant on the basis of experimental measurements, with the PV/T modules connected in series. A good level of correspondence was found between the measurements and the simulations obtained from a model of the system, particularly as regards electrical features.

Microbial communities of polluted sub-surface marine sediments

Microbial communities of coastal marine sediment play a key role in degradation of petroleum contaminants. Here the bacterial and archaeal communities of sub-surface sediments (5–10 cm) of the chronically polluted Priolo Bay (eastern coast of Sicily, Italy), contaminated mainly by n-alkanes and biodegraded/weathered oils, were characterized by cultural and molecular approaches. 16S-PCR-DGGE analysis at six stations, revealed that bacterial communities are highly divergent and display lower phylogenetic diversity than the surface sediment; sub-surface communities respond to oil supplementation in microcosms with a significant reduction in biodiversity and a shift in composition; they retain high biodegradation capacities and host hydrocarbon (HC) degraders that were isolated and identified. HC-degrading Alfa, Gamma and Epsilon proteobacteria together with Clostridia and Archaea are a common feature of sub-surface communities. These assemblages show similarities with that of subsurface petroleum reservoirs also characterized by the presence of biodegraded and weathered oils where anaerobic or microaerophilic syntrophic HC metabolism has been proposed.

A small scale Pressure Retarded Osmosis power plant: dynamics of the brackish effluent discharge along the coast

The feasibility of a small scale Pressure Retarded Osmosis (PRO) plant located along the eastern coast of Sicily (Italy) is assessed by considering fresh water intake from a river and salt water intake from the sea. Firstly, PRO design methods are applied in order to estimate potential power production in terms of both the availability of water resources and of local salinity gradients. Secondly, the discharge dynamics of the brackish plant effluent in the coastal waters is investigated using an hydrodynamic model, taking into account wave - current interaction close to the river mouth. The results of the numerical simulations allow to identify the area affected by the brackish discharge, as a function of the nearshore wave climate conditions. Results show that the plume propagation is mainly controlled by the wave direction, whereas significant wave height and peak wave period have a minor influence. Plume hydrodynamics analysis is useful in optimizing the layout of the PRO plant in terms of the placement of the sea water intake and the effluent discharge, both of which should be properly located outside the surf-zone. Plume hydrodynamics analysis is also important for the evaluation of PRO plant impacts on the coastal saline concentration which may affect the local ecosystems.

The ground beetle Parallelomorphus laevigatus is a potential indicator of trace metal contamination on the eastern coast of Sicily

Carabids are generally considered to be non-specialized predators, and they have been considered useful ecological indicators. They can play a key role in clarifying the route of contaminants in food webs because they are predators of small invertebrates and, in turn, part of the diet of several vertebrates. The Mediterranean species Parallelomorphus laevigatus, which so far has not been studied from an ecotoxicological point of view, is an excellent ecological indicator in sandy coastal environments.We investigated the accumulation of trace elements in Ionian populations of P. laevigatus and evaluated the transfer of metal through the food chain of the coastal ecosystem. We analyzed 15 metals, including 11 essential metals (Co, Cr, Cu, Fe, Mn, Mo, Ni, Se, Sn, V and Zn) and four toxic metals (As, Cd, Hg and Pb). Significant differences were found in metal concentration in animal tissues among sites.Our results support the existence of defense mechanisms for the studied species.High values of As, Cd, Cr, Pb, Ni, and Hg detected in the beetles from the control site can be explained by both the emission sources from the nearby industrial plants and the intense agricultural activity.The present paper shows increasing Hg concentrations in the simplified trophic web of sandy beaches and confirms the capability of this pollutant to biomagnify. Moreover, the high value of biomagnification factor (BMF) points to the severe pollution level in this protected area.

Intrinsic bioremediation potential of a chronically polluted marine coastal area

A microbiological survey of the Priolo Bay (eastern coast of Sicily, Ionian Sea), a chronically polluted marine coastal area, was carried out in order to discern its intrinsic bioremediation potential. Microbiological analysis, 16S rDNA-based DGGE fingerprinting and PLFAs analysis were performed on seawater and sediment samples from six stations on two transects. Higher diversity and variability among stations was detected by DGGE in sediment than in water samples although seawater revealed higher diversity of culturable hydrocarbon-degrading bacteria. The most polluted sediment hosted higher total bacterial diversity and higher abundance and diversity of culturable HC degraders. Alkane- and PAH-degrading bacteria were isolated from all stations and assigned to Alcanivorax, Marinobacter, Thalassospira, Alteromonas and Oleibacter (first isolation from the Mediterranean area). High total microbial diversity associated to a large selection of HC degraders is believed to contribute to natural attenuation of the area, provided that new contaminant contributions are avoided.