Search Results (26)

For archaeological studies, the expected outcome of a Ground Penetrating Radar (GPR) survey is a series of time-slices (or depth-slices) that mark the position of buried structures at different depths. The clarity of these time-slices is strongly site-dependent and is particularly worsened in the presence of even small percentages of clay, which strongly attenuates the GPR signal. This is the condition affecting the Greek–Roman archaeological site of Tindari (Sicily, Italy). Here, we performed a multichannel GPR survey particularly focusing on a residential insula. In order to increase the signal-to-noise ratio, we tested two processing strategies: a conventional in-line stacking and a new concept of off-line stacking. This last was performed dividing spatially adjacent channels of the GPR multichannel system into groups and stacking the signals of each group at each specific location. We observed that off-line stacking improves the signal-to-noise ratio in 2D sections and time-slices quality. Comparisons showed that off-line stacking has a clear advantage over traditional in-line stacking, at least for the specific application reported in this paper. Off-line stacking of GPR multichannel systems is, therefore, simple but very effective in increasing the investigation depth, especially in challenging environments. Full article

The well-known uncertainties in subsurface velocity field definition call for the integration of all the available data, including vintage seismic profiles, which, despite typically being in raster or paper format, often contain velocities derived from stacking and associated interval velocities. This study aims to build a velocity model for the time-to-depth conversion of an interpreted seismic reflection profile by using the interval velocity reported on a vintage, paper-format seismic profile and contribute to improving the subsurface geological model of the Sicily Channel, Central Mediterranean. Spline interpolation is used for velocity model building of the shallower part (3.5 sec TWT) of the seismic profile CS89-01, derived from the stacking velocities of 31 Common Depth Point (CDP) gathers. This was followed by the Gaussian convolution operator and a data exclusion filter to improve the accuracy of the velocity model. The time-to-depth-converted seismic reflection profile is a regional cross-section that covers almost the entire Sicily Channel, crossing part of the northern margin of the African Plate, from Tunisia to eastern Sicily. This study provides a new subsurface velocity field that can be applied, or taken into account, to most parts of the Sicily Channel when structural and stratigraphic interpretations are carried out at specific sites and where uncertainties in subsurface geological model exist (e.g., in the present study, the volcanic bodies in the Pantelleria Graben and Lampedusa High). Full article

It is suggested that the occurrence of tectonic activity in the northern Nubian belts (Tell-Rif and Atlas systems) since the Late Pliocene can be interpreted as one of the processes that were produced in the central and western Mediterranean zones by the collision of the Adriatic continental promontory with the Anatolian–Aegean Tethyan system. Since then, the consumption of the residual low-buoyancy domains in the Mediterranean area was allowed by a major change in the plate mosaic and the related kinematics. The new tectonic setting started with the decoupling of a large portion of the Adriatic domain (Adria plate) from Nubia, through the formation of a long discontinuity crossing the Ionian domain (Victor Hensen–Medina fault) and the Hyblean–Pelagian domain (Sicily channel fault system). Once decoupled, the Adria plate underwent a clockwise rotation, at the expense of E–W shortening in the Hyblean–Pelagian domain and in the northern Nubian margin. The shortening in the Pelagian domain was accommodated by the northward escape of the Adventure wedge, which in turn caused the northward displacement of the eastern Maghrebian sector. The indentation of these structures into the Alpine–Apennine material lying east of the Corsica–Sardinia block induced an east to southeastward escape of wedges (southern Apennines and Calabria). This occured at the expense of the remnant Ionian Tethys oceanic domain and the thinned Adriatic margin. The extensional regime that developed in the wake of the migrating wedges led to the formation of the central and southern Tyrrhenian basins. In the northern Nubian belts, the westward push of the Adria–Hyblean–Pelagian domain has been accommodated by oroclinal bending, thrusting and uplifting across the Tell and Atlas belts. This geodynamic context might explain some features of the seismicity time pattern observed in the Tell system. Full article

An analysis of 483 remotely operated vehicle (ROV) dives carried out along the Italian coast on hard substrata at mesophotic depths (40–200 m) allowed an overview of the rich sponge diversity (53 taxa) of the deep continental platform to be obtained for the first time. About 40% of the potential actual species diversity was recognisable using ROV, suggesting that this group is among the richest yet underestimated using this technology in contrast to other megabenthic taxa. Additionally, the study allowed us to gather data on the current basin-scale distribution and bathymetric limits of five common and easily identifiable demosponges with up to 55% occurrence in the explored sites: Aplysina cavernicola, the group Axinella damicornis/verrucosa, Chondrosia reniformis, Foraminospongia spp., and Hexadella racovitzai. Four of these latitudinal distributions were characterised by high occurrence in the Ligurian Sea and a progressive decrease towards the south Tyrrhenian Sea, with an occasional second minor peak of occurrence in the Sicily Channel. In contrast, Foraminospongia spp. showed a maximum occurrence on the offshore reliefs and a second one in the North–central Tyrrhenian Sea, while it was almost absent in the Ligurian Sea. Trophic and biogeographic reasons were discussed as possible causes of the double-peak distributions. The vertical distributions support a more consistent occurrence of all considered taxa in deeper waters than previously known. This suggests that they may more typically belong to the mesophotic realm than the shallow waters, owing to a more extensive sampling effort in the deeper depth range. The five target taxa are typical or associated species of seven reference habitats in the recently revised UNEP/SPA-RAC classification. However, they may create such dense aggregations that they should be listed as new facies in the abovementioned classification. Full article

The sea star Hymenodiscus coronata is the only Mediterranean representative of the deep-sea order Brisingida. In the North-eastern Atlantic Ocean, this species is known to create dense aggregations, while, in the Mediterranean basin, it is generally reported as scattered individuals. Through the analysis of the video footage obtained from an extensive ROV campaign carried out in the northern Strait of Sicily in 2021, over 2850 specimens were counted. The specimens, observed between 310 m and 714 m depth, showed a large variability in size and number of arms. It was noted that 17% of the specimens displayed the peculiar “sail position”, with all the arms extended vertically in the water column, possibly increasing the filtration rate. Almost the totality of the individuals was noted on soft bottoms, in accordance with the ecological preferences of the species. The density of H. coronata in each site varied between 0.01 and 0.81 individuals m⁻², with the highest densities reported in sites characterized by large muddy areas among rocky outcrops and turbulent hydrodynamic conditions. Although the trawling areas exploited in 2021 did not seem to interfere with the presence of H. coronata in the study area, a precautionary approach should be assumed to protect the largest ever reported Mediterranean aggregation of this poorly known species. Full article

Ground-based infrared cameras can be used effectively and safely to provide quantitative information about small to moderate-sized volcanic eruptions. This study describes an infrared camera that has been used to measure emissions from the Mt. Etna and Stromboli (Sicily, Italy) volcanoes. The camera provides calibrated brightness temperature images in a broadband (8–14 µm) channel that is used to determine height, plume ascent rate and volcanic cloud/plume temperature and emissivity at temporal sampling rates of up to 1 Hz. The camera can be operated in the field using a portable battery and includes a microprocessor, data storage and WiFi. The processing and analyses of the data are described with examples from the field experiments. The updraft speeds of the small eruptions at Stromboli are found to decay with a timescale of ∼10 min and the volcanic plumes reach thermal equilibrium within ∼2 min. A strong eruption of Mt. Etna on 1 April 2021 was found to reach ∼9 km, with ascent speeds of 10–20 ms⁻¹. The plume, mostly composed of the gases CO₂, water vapour and SO₂, became bent over by the prevailing winds at high levels, demonstrating the need for multiple cameras to accurately infer plume heights. Full article

The Sciacca basin extends in the southwestern part of Sicily and hosts an important geothermal field (the Sciacca Geothermal Field) characterized by hot springs containing mantle gasses. Newly acquired high-resolution seismic profiles (Boomer data) integrated with a multichannel seismic reflection profile in close proximity to the Sciacca Geothermal Field have documented the presence of numerous active and shallow fluid-related features (pipes, bright spots, buried and outcropping mud volcanoes, zones of acoustic blanking, and seafloor fluid seeps) in the nearshore sector between Capo San Marco and Sciacca (NW Sicilian Channel) and revealed its deep tectonic structure. The Sciacca Geothermal Field and the diffuse submarine fluid-related features probably form a single onshore–offshore field covering an area of at least 70 km². This field has developed in a tectonically active zone dominated by a left-lateral transpressive regime associated with the lithospheric, NNE-striking Sciacca Fault System. This structure probably favored the rising of magma and fluids from the mantle in the offshore area, leading to the formation of a geothermal resource hosted in the Triassic carbonate succession that outcrops onshore at Monte San Calogero. This field has been active since the lower Pleistocene, when fluid emissions were likely greater than today and were associated with greater tectonic activity along the Sciacca Fault System. Full article

Understanding the socio-economic channels through which farmers affect agro-biodiversity (ABD) represents a relevant research area, especially in the light of the new sustainable development paradigm. Supporting ABD is one of the main goals of the EU Green Deal and the agricultural sector is being called on for a higher commitment. Nowadays, ABD interventions are linked not only to the genetic and natural resources of species, but also to farming practices, land management, living standards in rural areas and all the policy interventions supporting them. However, the existing literature is still mainly focused on the environmental and agronomic perspectives. This paper aims to assess the extent to which different socio-economic and policy factors affect the performance of farmers in supporting ABD at the territorial level. Starting from the FADN data and focusing on Italy, we built a new regional comprehensive indicator that accounts for three levers through which farmers mostly interact and can influence ABD: land use strategies, agriculture practices and management decisions, and Common Agricultural Policy (CAP) funds. Results reveal a heterogeneous spectrum of indicator scores at the regional level. Land use strategies have a significant relevance for the North-East regions and the Islands (Sicily and Sardinia), whereas agricultural practices emerge as the primary influential factors in the Centre and South. Policy funds dominate in the North-West, reflecting the greater expenditure capacity of the northern regions. These findings have important policy implications for the future of the CAP and the biodiversity EU strategy. Full article

A new understanding of plankton ecology has been obtained by studying the phenotypic traits of free-living prokaryotes in the Sicily Channel (Central Mediterranean Sea), an area characterised by oligotrophic conditions. During three cruises carried out in July 2012, January 2013 and July 2013, the volume and morphology of prokaryotic cells were assessed microscopically using image analysis in relation to environmental conditions. The study found significant differences in cell morphologies among cruises. The largest cell volumes were observed in the July 2012 cruise (0.170 ± 0.156 µm³), and the smallest in the January 2013 cruise (0.060 ± 0.052 µm³). Cell volume was negatively limited by nutrients and positively by salinity. Seven cellular morphotypes were observed among which cocci, rods and coccobacilli were the most abundant. Cocci, although they prevailed numerically, always showed the smallest volumes. Elongated shapes were positively related to temperature. Relationships between cell morphologies and environmental drivers indicated a bottom-up control of the prokaryotic community. The morphology/morphometry-based approach is a useful tool for studying the prokaryotic community in microbial ecology and should be widely applied to marine microbial populations in nature. Full article

Geryon longipes is a crab species that inhabits the muddy bottoms of the middle and lower slopes, as well as bathyal bottoms ranging from 400 to 2000 m in depth. To assess its molecular diversity, a fragment of 572 bp of the COI (Cytochrome Oxidase subunit I) mitochondrial gene was sequenced in eight Western Mediterranean locations. Within the studied area, two oceanographic fronts are present (Almeria-Oran Front and Ibiza Channel). From the 124 sequences obtained, only 7 distinct haplotypes were identified. The population distribution indicated three well-differentiated regions: the Alboran Sea, the Gulf of Vera and the Levantine/Catalan coasts. The molecular diversity was compared with that obtained in the same year for the same gene in Liocarcinus depurator, a crab species that is captured on the continental shelf and upper slope (40 to 500 m). The estimates of molecular diversity parameters for the COI gene fragment were rather similar between both species, but the number of haplotypes was higher for L. depurator. Finally, the obtained COI sequences of G. longipes were compared to those from other populations of the species distribution range, recovered from the DNA repository. Only one additional, different haplotype was reported (Sicily), whereas all the rest were common with those described in our study. Therefore, the COI gene fragment would indicate that all the sequences analysed in the Mediterranean and NE Atlantic belong to the same species, G. longipes. Full article

The precious red coral (Corallium rubrum L.) represents one of the most fascinating marine species of the Mediterranean Sea. Several samples, including red coral together with its accompanying species, were found in the zoological collection of the Italian pioneer biologist Lazzaro Spallanzani (1729–1799), collected in the Messina Strait during his voyage in Sicily (1788). The study of these samples allowed the inclusion of numerous additional species in the traditional red coral facies as the large oyster Neopycnodonte cochlear, the giant barnacle Pachylasma giganteum, the mesophotic scleractinian Caryophyllia (Caryophyllia) cyathus. These specimens proved to be very useful in describing the diversity of the paleo-community including red coral, shedding light on its formation processes. In particular, some specimens are composed of red coral rubble consolidated and cemented with other carbonatic remains Probably, these peculiar specimens have a similar origin to those of the Sciacca Banks already known from the Sicily Channel. In fact, the two areas are prone to intense seismic activity that periodically causes mass mortalities of red coral from nearby rocky reliefs and the formation of biogenic detritus, while the resulting chemical environment of the water and the sediments allows the consolidation of the carbonatic remains. Full article

Compared to their fossil counterparts, living brachiopods are investigated far less often, due to their occurrence in remote environments such as dark caves or deep environments. Due to the scarcity of studies targeting in situ brachiopods’ populations, large-scale information on their distribution and ecological preferences is still lacking, especially on hardgrounds. The extensive employment of remotely operated vehicles (ROVs), however, has opened up the chance to better explore this taxon’s diversity and ecology in the mesophotic and bathyal zones. The analysis of over 600 h of video footage collected from 624 sites, from 40 m to 1825 m, located along the Ligurian and Tyrrhenian coasts of Italy and the Sicily Channel, allowed for a large-scale investigation. The four identified species, Novocrania anomala, Gryphus vitreus, Megerlia truncata and Terebratulina retusa, emerged as common macrofaunal components of the explored habitats, especially between 150 m and 250 m, with high occurrences in the northern areas, especially on offshore seamounts. All species can form dense aggregations of individuals, with M. truncata showing the densest populations on steep rocky terraces (up to 773 individuals m⁻²). Except for G. vitreus, the only species also recorded on soft bottoms, the others were found exclusively on hardgrounds, with N. anomala showing a peculiar ability to exploit anthropogenic substrates such as terracotta amphorae. No stable species-specific associations were noted, even if numerous species were frequently observed together. Although brachiopods do not show the conspicuous tridimensionality of large filter-feeders, their substrate occupancy and their role in pelagic–benthic processes support their importance in deep-sea Mediterranean ecosystems. Full article

The main purpose of this article is to give a general idea of the scientific activity that was carried out starting from the 2000s on the basis of the data collected in the plots installed at the Sparacia experimental station for soil erosion measurement in Sicily, South Italy. The paper includes a presentation of the experimental site, a description of the methods and procedures for measuring soil erosion processes both available in the literature and applied at the Sparacia station (sediment sampling and water level reading in the storage tanks for total erosion measurements; profilometer, and Structure from Motion technique for rill erosion measurements), and the main results obtained in the monitoring period in the experimental site. The latter concern the effects of plot size and steepness on soil loss, the measurement variability, the frequency analysis of soil loss, the rill erosion characterization, and the comparison between rill and interrill erosion rates. Each of these topics is addressed with multi-temporal analyses performed with increasing size of the available database, which allowed to draw robust conclusions. Soil loss did not vary appreciably with plot length in contrast with the assumption made in the USLE/RUSLE. The variability of the measurements of soil loss, runoff volume, and sediment concentration at the event scale in replicated plots decreased as the mean measured value increased. The normalized event soil loss was distributed according to a two-component distribution. A power relationship between rill volumes and lengths was established. The measurements also confirmed the morphological similarity between the channels of the rills and ephemeral gullies described by a power dimensionless relationship. Rill erodibility of the sampled clay soil varied over time, maintaining relatively low values. Finally, rill erosion was dominant relative to interrill erosion, and a more efficient sediment transport system through the rill network occurred as plot steepness increased. Full article

The European anchovy is an important fishing resource in the Sicilian Channel that supports a high recruitment success variability. The presence of two spawning areas, the drifting of the larvae along the currents and the different oceanographic conditions within the region suggest the presence of different larvae subpopulations. Morphometric and biochemical approaches have been used to analyze the differences among larvae collected. The amino acid composition discriminates two larval groups closely related to the spawning regions: Adventure Bank and the shelf between the South of Sicily and Malta. In addition, there are morphometric and growth differences between recently hatched larvae in these two regions, reinforcing the hypothesis of two larval subpopulations and suggesting differences in the parental reproduction effort. Between the South of Sicily and Malta there are growth and biochemical composition differences since larvae from the Maltese coast present a higher protein content and a bigger growth rate than those from Sicily, pointing out that Malta is an area with a better nutritional condition environment. No differences in the growth rate have been observed between the Adventure Bank area and the Maltese shelf, therefore, a diverse nutritional condition cannot be suggested between these two areas despite the Maltese larvae having a higher protein content present. Full article

The recent (<190 ka) volcanic history of Pantelleria is characterized by the eruption of nine peralkaline ignimbrites, ranging in composition from comenditic trachyte to comendite to pantellerite. The ~46 ka Green Tuff (GT) was the last of these ignimbrites, which was followed by many effusive and explosive low-volume eruptions of pantellerite from vents within the caldera moat and along the caldera rim. Although recent studies have shed additional light on the age, petrochemistry, and volcanology of the older ignimbrites, there is very little knowledge of magmatism that occurred between these older ignimbrites, primarily due to the very scarce exposures. In this paper, we present new field descriptions and geochemical data for three local peralkaline centers never studied before, two pre-GT and one post-GT, which share a similar setting with respect to the caldera scarps but differ in terms of their age, composition, and eruptive style. These centers include: (i) the older (~125 ka) Giache center (comenditic trachyte), (ii) the ~67 ka Attalora center (comendite, pantellerite), and (iii) the younger (~14 ka) Patite center (pantellerite). Full article