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Earlier studies on Holocene fills of upland lakes (Lago Forano and Fontana Manca) in northern Calabria, Italy, showed that these hold important palaeoecological archives, which however remained poorly dated. Their time frame is improved by new 14C dates on plant remains from new cores. Existing pollen data are reinterpreted, using this new time frame. Two early forest decline phases are distinguished. The earliest is linked to the 4.2 kyr BP climatic event, when climate became distinctly drier, other than at Lago Trifoglietti on the wetter Tyrrhenian side, where this event is less prominent. The second is attributed to human impacts and is linked to middle-Bronze Age mobile pastoralism. At Fontana Manca (c. 1000 m a.s.l.), it started around 1700 BC, in the higher uplands a few centuries later (Lago Forano, c. 1500 m a.s.l.). In the Fontana Manca fill, a thin tephra layer occurs, which appears to result from the AP2 event (Vesuvius, c. 1700 BC). A third, major degradation phase dates from the Roman period. Land use and its impacts, as inferred from the regional archaeological record for the Raganello catchment, are confronted with the impacts deduced from the palaeoarchives. [ABSTRACT FROM AUTHOR]

Highlights • Microplastics were found in coastal waters and in fish gastrointestinal tract from the Tyrrhenian Sea. • Microplastics appeared in fragments or in filamentous shapes, in water and in fish respectively. • Microplastics have been characterized by FT-IR and Raman spectroscopies. Abstract In this work it is reported for the first time the characterization of microplastics from sea water samples and in two congener species of seabreams: Pagellus erythrinus and P. bogaraveo, Mediterranean fish species of great commercial importance. An experimental survey was conducted on May–June 2017 in the southernmost part of the Tyrrhenian Sea. Microplastics found in the sea water and in the grastrointestinal tract of two teleosts were characterized by Raman and IR spectroscopies. Microplastics found in sea water samples appeared in the form of fragments made of plastics of low and high density (PVC and LPDE). All the microplastics found in fish belonged to Nylon 66, typical fibers used in industry and in fisheries. Our findings highlighted the importance of further studies along the food web chain for a better understanding of the diffusion and possible consequences of this terrible threat. [ABSTRACT FROM AUTHOR]

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Abstract Understanding drivers of fish maturity are essential to predict the productivity, stability, and resiliency of exploited populations. In terms of horse mackerel (Trachurus trachurus), in the eastern Atlantic Ocean and the Mediterranean Sea, size at maturity estimates date back to the 1940s and throughout its range. However, many older estimates may not reflect current maturity rates. This is because past methods were imprecise, or environmental or fishing effects may change maturity rates, and some stock areas have been overlooked. To address this data gap for the Central Mediterranean Sea, female horse mackerel size at maturity was estimated for two areas: the Strait of Sicily and the Tyrrhenian Sea. All ovaries were assigned a reproductive phase based on macroscopic methods, and the reliability of this method (94%) was validated with a microscopic method (i.e., gonad histology). Although the collected females exhibited similar condition, in terms of total body weight at a given length, as well as similar gonad-somatic indices, the size at median maturity in the Strait of Sicily was smaller (161 mm total length [TL]) than in the Tyrrhenian Sea (176 mm TL). Future sampling in a series of years with contrasting levels of productivity may help identify whether this is a broad latitudinal trend, or due to specific oceanographic drivers, such as estuarine outflow into the Tyrrhenian Sea or upwelling in the Strait of Sicily. Meanwhile, resource assessments should consider that these two areas represent two phenotypic stocks. [ABSTRACT FROM AUTHOR]

The longest historical time series (14 years, from 2003 to 2016) of temperature and salinity of thermohaline staircases with highly homogeneous and reliable data ever observed is here presented and studied. The thermohaline staircase system of the central Tyrrhenian Sea is due to double diffusion in salt finger regime, and our study reveals its conservative behavior, oscillating among slightly different shapes, passing through merging processes, with a systematic upward drift of the interfaces. Data also show enhanced salt finger processes after 2010, near the bottom, promoted by the ingression from the Western Mediterranean of a new denser water mass due to the Western Mediterranean Transition. Our results are relevant for studying the mixing in the intermediate and deep region and open the way for modeling and theoretical follow‐up studies aimed to reproduce and explain these observations. Plain Language Summary: This study deals with a microscale mixing process usually denoted as double diffusion. Seawater masses contain different quantities of heat and salt and can be recognized by their resulting density. The molecular diffusion of heat is quicker than that of salt, resulting in a slow but very efficient mixing at the interface between two different water masses. In the Tyrrhenian Sea this peculiar phenomenon is well visible and shows very high persistency and progression: Vertical profiles of temperature and salinity look, in fact, like a staircase; such profiles have been first observed in the 1970s. Tyrrhenian staircases show variability; in particular, they have been used as a proxy to infer general water mass property changes (in turn linked to climate change), confirming the presence of a new, denser water at the bottom of the basin, and its ability to mix very quickly. Moreover, this study shows the longest time series ever observed. Key Points: This study deals with the longest thermohaline staircases time series ever observed, steps characterization and behaviorWe provide evidence of self‐regulating and merging in a thermohaline staircase systemWe evidence the quick mixing due to salt fingers in the Tyrrhenian interior [ABSTRACT FROM AUTHOR]

Abstract Flow reversals within the Corsica Channel, a strait East of Corsica, are investigated with a realistic, high-resolution (∼ 1.5 km) numerical setup simulating the year 2004. The simulations compare well with available water mass transport estimates resulting in an annual mean of 0.49 ± 0.49 Sv. Similarly, the model agrees with hydrographic observations in the area, and current velocity measurements showing a flow in the Corsica Channel predominantly directed northward from the Tyrrhenian to the Ligurian Sea. On top of the well-documented Corsica Channel seasonal variability, a higher-frequency variability can be found throughout the year but more frequently during the summer season. This temporal variability, highest close to the western flank of the Channel, is of the order of a few days to a week and associated with reversals of the currents. We find that this variability is ascribed to periodic intrusions of the West Corsica Current on the Eastern side of the Island. Moreover, our findings suggest the importance, of a so-far neglected, across-channel variability of the meridional velocity throughout the entire 2004. This result potentially questions the single-mooring assumption that has always been at the center of the observational scheme. This assumption holds while looking at low-frequency/seasonal variability but fails when focusing on higher-frequency variability. Highlights • High-resolution numerical model of the circulation around the Corsica Channel. • Model outputs compare well with observations and the seasonal signals are reproduced. • Higher-frequency variability associated with flow reversals in the Corsica Channel. • Significant across-channel variability of the meridional flow field. • Single-mooring assumption, at the center of the observational scheme, is questioned. [ABSTRACT FROM AUTHOR]

Highlights • We present regional ocean simulations driven by a new set of atmospheric fields. • Tyrrhenian large-scale circulation is well captured with 50 km and 25 km fields. • Resolved dynamical structures are better represented with fields of 25 km. • Improvements with 25 km fields are largely set by wind representation. Abstract The Tyrrhenian circulation, driven by the interplay of transport at its main straits and local climate, presents a marked seasonal variability. In this work we investigate the role of the horizontal resolution of the atmospheric fields in the long-term seasonal variability of the Tyrrhenian Sea circulation. We adopt the eddy-permitting ocean circulation model NEMO-MED12. Simulations cover the 1997–2008 period and are driven by atmospheric fields from PROMES regional climate model with a horizontal resolution of 50 km and 25 km. Given that this is the first time that PROMES variables have been used to run ocean simulations, we first evaluate the overall performance of this setup taking into consideration the entire model domain, which covers the whole Mediterranean Sea. We show that PROMES variables allow a good representation of the Mediterranean boundary fluxes and water masses. Focusing on the Tyrrhenian Sea, the comparison of the model results to altimeter data shows that the main features of the seasonal variability of the Tyrrhenian large-scale circulation are well captured regardless of the resolution of the atmospheric fields. However, the prescription of 25 km resolution atmospheric fields improves substantially the representation of the dynamical structures resolved by the model. Based on our results, we update intermediate-depth circulation patterns, very little studied so far. We show that changes observed with 25 km fields are not due to a better simulation of transport across Corsica, Sardinia and Sicily straits, but rather to the improved representation of winds. [ABSTRACT FROM AUTHOR]

Abstract In continental margins, canyons appear to act as natural conduits of sediments and organic matter from the shelf to deep basins, providing an efficient physical pathway for transport and accumulation of particles with their associated land-produced contaminants. However, these mechanisms have not been yet sufficiently explored by geochemical markers. The continental slope of the south Sardinia has been used as a natural laboratory for investigating mechanisms and times of transfer dynamics of contaminants from land to sea and from shelf to deep sea through an articulated system of submarine canyons. Here, dynamics of contaminants have been investigated in a pilot area of the central Mediterranean basin (Gulf of Cagliari, S Sardinia) where important industrial plants are sited since beginning of the last century. Five sediment cores dated by 210Pb and 137Cs reveal: i) a complex dynamics of organic and inorganic contaminants from point source areas on land to the deep sea and ii) a crucial role played by canyons and bottom morphology as primary pathway conveying sediments and associated contaminants from sources to very far deep sea environments. In particular, this study provides new integrated tools to properly understand mechanisms of connection between coastal sectors and deep sea. This is challenging mostly in regions where coastal pollution could represent critical threats for larger areas of the Mediterranean Sea. Graphical abstract Unlabelled Image Highlights • Bottom morphology reveals a complex and articulated system of submarine canyons. • High-resolution stratigraphic markers for sedimentary marine records • Canyons as primary pathway conveying sediments and associated contaminants. [ABSTRACT FROM AUTHOR]

Highlights • The properties of the Tyrrhenian Intermediate Water (TIW) are investigated. • Argo float, XBT, and dissolved oxygen data are used to characterize the TIW. • Data and model simulations are used to illustrate the TIW formation process. • TIW outflow is shown to affect the hydrology of the Western Mediterranean. • Recent changes in the TIW properties are highlighted, due to warming effects. Abstract This work focuses on the Tyrrhenian Intermediate Water, a water mass present in the Tyrrhenian Sea (Western Mediterranean Sea), which approximately lies between 100 m and 200 m of depth, and is characterized by a local minimum of temperature. Here, for the first time, a thorough investigation of the Tyrrhenian Intermediate Water has been performed, based on the analysis of long time series of observations (XBT, Argo float, dissolved oxygen data) and on modeling results. It was found that this water is present in a large part of the Tyrrhenian basin, and is a persistent feature of the basin hydrology. It is formed by winter convection, with some differences between the southern part of the basin and the northern part, where strong winter cooling produces deeper convection and mixing. The process of formation of the Tyrrhenian Intermediate Water has been investigated in detail, through the analysis of the experimental datasets, of dedicated numerical experiments with a one-dimensional mixed layer model, and of the outputs of a three-dimensional ocean circulation model. Such analysis has excluded remote contributions from intermediate waters produced in the western portion of the Western Mediterranean basin. On the other hand, the presence of the Tyrrhenian Intermediate Water has been found to impact not only the Tyrrhenian Sea hydrology, but also that of the adjacent Liguro-Provençal basin, because this water mass outflows from the Corsica Strait, and is transported as far as the Gulf of Lion, in the core of the region where deep waters are formed. Recent changes in the properties of this intermediate water mass have also been highlighted, which result from the warming of the neighboring water layers. [ABSTRACT FROM AUTHOR]

The brown trout (Salmo trutta L.) is widely distributed all around Europe but its natural diversity is threatened by massive stocking with Atlantic domestic strains. Describing the remaining natural genetic diversity and the proportion of domestic hatchery strains in rivers is a prerequisite for smart conservation. The high genetic diversity of brown trout populations around the Tyrrhenian Sea is well known. Use of twelve microsatellites has allowed description of the natural genetic structure of populations and detection of the consequences of stocking. Mitochondrial DNA control region sequences and the LDH-C1* gene enabled placement of each population into one of the six mitochondrial and two allozymic known evolutionary lineages. The Corsican populations showed low intra-population genetic diversity but an exceptionally high level of inter-population differentiation. More southern Tyrrhenian regions exhibited opposite pattern of diversity, partly due to the Atlantic domestic introgression. Globally, the natural structure outlines two north-south clines: high inter-population differentiation and predominance of the Adriatic lineage in the north, but lower inter-population differentiation and the presence of the natural Atlantic lineage in the south. In addition, the Tyrrhenian region is the contact zone between the widespread Adriatic lineage and a local natural Atlantic lineage probably coming from North Africa through the Strait of Gibraltar. [ABSTRACT FROM AUTHOR]

In this study, a baroclinic coastal trapped wave, with period ~ 4.5 days and cross-shore scale ~ 3 km, is identified in the outputs of a very-high-resolution ocean circulation model of the Campania coastal system (central Tyrrhenian Sea; including the Gulfs of Salerno, Naples, and Gaeta). The outputs are from a simulation spanning June 2003, a month in which the surface winds were always weak, except for a strong northeasterly wind event that lasted 1 day (20 June). This event is found to generate a strong upwelling along the Campania coasts, whose relaxation—virtually free, because of the weakness of the winds—produces coastal current fluctuations that propagate to the north, spanning the three gulfs. The dynamics (analyzed with a focus on the Gulf of Naples) is found to share important features with baroclinic Kelvin waves in a two-layer model, such as the sharp cross-shore decrease of the perturbation amplitude and the vertical reversal of the long-shore current velocities. The simulated phase speed, cross-shore extension, and wavelength of the perturbation are also close to those obtained using a two-layer approximation of the dynamics. Moreover, the propagation described by the models is shown to be compatible with current measurements that were made in June 2003 at the southern entrance of the Gulf of Naples. Experimental implications related to the specific oceanographic problem are finally discussed, and an experimental strategy—inspired by our modeling approach—aimed at identifying the phenomenon is proposed. [ABSTRACT FROM AUTHOR]

The paraonid polychaete Aricidea fragilis Webster, 1879, a typically west-Atlantic species, is reported from the Mediterranean Sea on the basis of several individuals, from the Adriatic and Tyrrhenian Sea. Its differences with the other Mediterranean Paraonidae, and in particular with the morphologically close Aricidea suecica meridionalis Laubier & Ramos, 1974, are briefly discussed. The possible status of A. fragilis as an alien species in European waters is analysed. The scarcity of historical records, the relatively restricted distribution, and the population dynamics observed in European waters strongly support the hypothesis of an introduction, despite the wide temporal interval between the first record of the species in the 1930s and the currently ongoing range expansion and population explosion. Here we precautionarily suggest considering A. fragilis a cryptogenic species. [ABSTRACT FROM AUTHOR]

Abstract The Marsili Basin (in the southern Tyrrhenian Sea), whose mode of extension is still a controversial issue, is the youngest bathyal basin of the Central Mediterranean. A thin sedimentary cover in the basin permits to image basement fabric and structure by swath mapping and seismic reflection data. We investigate the crustal structure of the southern Tyrrhenian Sea, extending from the bathyal Marsili Basin to the adjacent Sicily continental margin. Interpretation of seismic reflection profiles (calibrated by well and dredge data) and crustal cross-sections were used to identify the stratigraphic infill, structural pattern and large-scale crustal features of the region. We recognized three basins in the southern Tyrrhenian Sea: (1) the Termini basin that is an overfilled sedimentary basin on the continental shelf area; (2) the Cefalù basin, located on the continental slope area and filled by thick deep water turbidite deposits; (3) the distal Marsili basin, filled by hemipelagic and thin distal turbidite deposits. The sequence stratigraphy interpretation permitted us to recognize fourth-order depositional sequences and the stratigraphic signature of the rift stages. An important increase in the sedimentary supply from the continental shelf to the bathyal basin occurred approximately over the last 0.5 Ma and is related to the uplift of the coastal area. The stratigraphic constrains indicate a Lower Pleistocene age for the opening of the southern Tyrrhenian Sea basin. The structural map reveals a complex fault pattern, in which coeval normal faults disclose a triangular basin from the Marsili bathyal basin to the Sicily continental margin, associated to an Euler pole in the northern Sicily. Tacking in account the faults pattern that developed in the whole Southern Tyrrhenian Sea during the Lower Pleistocene, we reconstructed two opposite triangular basins separated by a perpendicular rift. For analogy with the contiguous Vavilov basin, we propose that the extension in the Marsili basin reached the mantle exhumation stage. Highlights • We combine the analysis of geological data and a recent seismic tomography model. • We described a triangular extensional basin from the shelf to the bathyal region. • We recognized fourth-order depositional sequences Pleistocene in age. [ABSTRACT FROM AUTHOR]

Trypanorhynch cestodes are common parasites of marine fish with complicated life cycles which have been suggested as model taxa to study the evolution of marine helminth parasites and their life cycles. Among the Trypanorhyncha, the genus Grillotia includes 18 valid species, of which only four have been found in Mediterranean fish hosts. Morphological, histopathological, and molecular data are presented on a massive Grillotia plerocercus infection in an anglerfish (Lophius piscatorius) from the Tyrrhenian Sea. BLAST analysis of the 28S rDNA sequences revealed 99% similarity between specimens here found and a G. (Bathygrillotia) rowei sequence available in GenBank with a total of six nucleotide site differences. A morphological study suggested that the Grillotia sp. here reported did not match important characters to those previously reported from the Mediterranean Sea. Taking in account these differences, we prefer to place these specimens within Grillotia sensu lato until more material is available for study including sequences from adult specimens of Grillotia spp. from the Mediterranean Sea. [ABSTRACT FROM AUTHOR]

This paper describes the data processing that led to the definition of ecological classification criteria for the Biological Quality Element (BQE) phytoplankton in the coastal waters (CW) of the Adriatic and Tyrrhenian seas, according to the Water Framework Directive (2000/60/EC). The chosen metric was the annual geometric mean of chlorophyll a concentrations owing to the log-normal nature of chlorophyll a distribution. The sensitivity of this metric to the gradient of pressures was tested by adopting an empirical statistical approach. The dilution factor (F_dil), which is the share of freshwater in a sample of seawater, was introduced as a rough, but realistic proxy of nutrient loads from the continent. Correlations between F_dil and trophic indicators (i.e. nitrogen and phosphorus concentrations in seawater and the respective N:P ratio) were then evaluated. The F_dil approach was also used to derive reference conditions for each typology of coastal waters. Functional relationships between chlorophyll a , as phytoplankton biomass indicator, and nutrient concentrations, as pressure indicators, were computed by means of regression techniques. The classification scale for the BQE phytoplankton was based on the TRIX scale of water quality conditions. Reference conditions, pressure/impact relationships, boundary setting and classification criterion definition were treated separately and discussed for each of the CW Types: Type I, Type II A Adriatic, Type II A Tyrrhenian and Type III W for both the Adriatic and Tyrrhenian seas. Due to the lack of a functional relationship between the gradient of pressures and chlorophyll a , and a narrow range of annual chlorophyll a concentrations, only one threshold value was set for Type III W instead of the whole classification scale. Specific topics dealing with the log-normal model adopted for chlorophyll a data and the adequacy of classification criteria are discussed in the Appendix. [ABSTRACT FROM AUTHOR]

Abstract This study reports data on benthic litter abundance, composition and distribution obtained during deep-sea trawl surveys conducted along the Sardinian continental margin down to the bathyal plain, at depths comprised from 740 to 1740 m. None of the investigated sites was litter free. Density ranged from a minimum of 4 to a maximum of >1300 litter items per km2, with a mean value of 258 ± 59 items. Plastic accounted for 56% of the total collected items, followed by glass (24%), metal (10%). Most items, irrespectively of the category, were single-use items. Fish abundance in all of the investigated catches was significantly higher than the number of litter items, the weight of which was similar to the reared fish biomass. Our results confirm that anthropogenic waste has reached the deep Mediterranean Sea, and that the most recent EU legislation banning single-use plastic tools represents a timely and necessary measure. Highlights • 25 sites from Sardinian bathyal plain were investigated through trawl survey. • Plastic was the most abundant category, followed by glass and metal. • Single-use items were the dominant category of benthic litter. • Density of biological catches was significantly higher compared to litter density. • Weight of biological catches was similar to benthic litter mass, regardless depth. [ABSTRACT FROM AUTHOR]

Abstract This study focuses on plastic distribution levels (shape, size, colour, type) in sediments from the coastal area of Cecina (Tuscany, Italy). Samples are collected in three sampling stations along six transect settled randomly along the shoreline and along the final tract of the Cecina river. Recorded plastic size ranges within 62.51–13,462 μm (average values 1591 ± 837 μm). Microplastics (<5000 μm) represent over than 97% of the total even if mesoplastics (5000–25,000 μm) are also recorded (2%). Over than 60% of recorded plastic items are higher than 500 μm. Measured levels range within 72 (ST2)–191 (ST4) items/kg d.w. Fragment > Fiber > Granule in each of the tested sampling site. Plastic litter levels recorded in study evidence low pollution compared to the existing literature supporting the occurrence of good environmental levels in Cecina coastline for the "Marine litter" descriptor. Highlights • Plastic litter in sediments from Cecina estuary and coastline were recorded. • Microplastics represent over than 97% while mesoplastics are about 2% of the total. • Measured levels range within 72–191 items/kg d.w. and fragments dominate. • Cecina sediments resulted lowly polluted by plastic litter compared to existing literature. [ABSTRACT FROM AUTHOR]

The high-resolution Campania Regional Ocean Model (CROM), coupled with an online Lagrangian particle tracking algorithm, is used to investigate the horizontal and vertical behavior of different (in terms of size and density) plastic polymer types during February and August 2016 in the Gulf of Naples. The transport of passive particles is evaluated based on the three-dimensional Eulerian velocity fields provided by the ocean model. The virtual particles are released in several hot spot areas in the Gulf of Naples where most of the marine debris is supposed to come from. A sensitivity analysis on the vertical sinking for negatively buoyant particles is carried out. The sinking behavior is determined by the settling velocity, which depends on the physical properties of the individual litter item as well as on the hydrodynamical features of the marine environment. Different numerical experiments are carried out to evaluate the effect of marine dynamics on three-dimensional transport. • 3D Lagrangian tracking plastic in the Gulf of Naples using the high-resolution Campania Regional Ocean Model • Sensitivity analysis on the vertical sinking for different plastic polymer types • Assessment of residence times and potential accumulation zones of the involved pollutants • Influence of seasonal hydrodynamical features of the water column on particle dynamics [ABSTRACT FROM AUTHOR]

Since the Tortonian, the geodynamic evolution of the Tyrrhenian Sea has been driven by an eastward roll-back of the entire Apennine subduction system, triggering distinct episodes of back-arc basin formation with spots of oceanic crust. Major structural differences are observed between northern and southern portions of the Tyrrhenian Sea, reflecting two distinct evolution stages of the Ionian slab retreat. In the central portion of the Tyrrhenian Sea, the seafloor morphology is characterized by a set of magmatic intrusions and structural highs associated to an E–W magnetic lineament along the 41st geographical parallel. The Vercelli seamount represents one example of structural highs correlated to Miocene magmatic episodes along the 41st parallel zone. In this study, we discuss the results of new high resolution magnetic data and morphological mapping of the Vercelli seamount acquired during the VER2010 cruise. The seamount represents the relict part of a granitic intrusion emplaced during the Tortonian phase of Tyrrhenian rifting. Tectonic and deep-sea erosive processes have jointly modified the seamount structure that can be observed nowadays. Cumulative gradient analysis highlights an asymmetric morphology of the flanks as a result of erosive action of opposite water mass gyres which modelled the southern portion of the seamount. The joint interpretation of magnetic and bathymetric datasets identifies a high magnetized source laying close to the base of the seamount and located in correspondence to a small basin. This structure has been modelled as a post-Tortonian lava sequence emplaced between structural highs in correspondence of N–S elongated flat sedimentary basin. Modelling of new geophysical data highlights the relationship between crustal setting and magnetic evidences of the central Tyrrhenian Sea, providing a new interpretation of the 41st magnetic lineament.

This work presents an 18-year-long (2002–2019) tide-gauge dataset collected on the Island of Ischia (Gulf of Naples, Southern Tyrrhenian Sea) that can contribute to the analysis of the basic features of sea-level variability in this region. Analysis of tidal constituents shows that the Gulf of Naples is characterized by the absence of any amphidromic system. In this area, sea-level changes due to the astronomical component of the tide are generally limited to ±20 cm with respect to the mean sea level, but the impact of this variability is enhanced by global sea-level increase and the effect of regional atmospheric perturbations that might also triple sea-level variations. The effects of these events, whose frequency has increased in recent decades, has been dramatic in coastal areas where intense social and economic activity occurs, e.g., in Ischia. On interannual time scales, the results indicate that the relative sea-level rise in Ischia has a magnitude of 3.9 mm/year. Special attention is dedicated to the “acqua alta” episodes and to their linkage with long-term sea-level trends and atmospheric forcing.

Rhodolith beds (RBs) are bioconstructions characterized by coralline algae, which provide habitat for several associated species. Mediterranean RBs are usually located in the mesophotic zone (below 40 m), and thus are frequently remote and unexplored. Recently, the importance and vulnerability of these habitats have been recognized by the European Community and more attention has been drawn to their investigation and conservation. This study reports the results of an extensive monitoring program, carried out within the Marine Strategy Framework Directive (2008/56/EC), in six sites off the Campania coast (Italy, Mediterranean Sea). New insights were given into the distribution, cover, vitality (i.e., live/dead rhodolith ratio), structural complexity, and coralline algae composition of RBs. Remotely operated vehicles (ROV) investigations allowed the description of several RBs, and the discovery of a RB with rhodolith cover >65% offshore the Capri Island. Only two sites (Secchitiello and Punta Campanella) showed a very low mean cover of live rhodoliths (Lithothamnion dominated all sites, and Phymatolithon calcareum and Lithothamnion corallioides, protected by the Habitats Directive (92/43/EEC), were detected in all RBs.

Sulcascaris sulcata (Anisakidae), a pathogenic nematode of sea turtles, may cause ulcerous gastritis with different degrees of severity. Previous studies demonstrated a high prevalence of infection in the Mediterranean loggerhead turtle (Caretta caretta), although no data on the potential intermediate hosts of this nematode has been published thus far from the Mediterranean basin. Here, using molecular analyses, we demonstrated that the cross sections of nematode larvae observed histologically in Mediterranean mussels (Mytilus galloprovincialis) collected from a farm along the Tyrrhenian coast of southern Italy belong to S. sulcata. The BLAST analysis of sequences at the ITS2 region of rDNA and mtDNA cox2 gene loci here obtained from samples of two Mediterranean mussels containing nematode larvae showed 100% homology with those at the same gene loci from the adults of S. sulcata collected from the Mediterranean Sea and deposited in GenBank. To our knowledge, this study is the first to present data on a potential intermediate host of S. sulcata in the Mediterranean basin and to report a nematode parasite from the Mediterranean mussel.

The central Mediterranean Sea is among the most oligotrophic habitats in the marine environment. In this study, we investigated the abundance, diversity and activity of prokaryoplankton in the water column (25–3000-m depth) at Station Vector (Tyrrhenian Sea, 39°32.050′ N; 13°22.280′ E). This specific water column consists of three different water masses (Modified Atlantic Water (MAW), Levantine Intermediate Water (LIW) and Tyrrhenian Deep Water (TDW), possessing a typical stratification of the Central Mediterranean basin. CARD-FISH showed that the metabolically-active fraction of bacterial populations exceeded the archaeal fraction along the whole water column, except at the deepest water masses. 16S rDNA and 16S rRNA clone libraries obtained from each type of water mass were used to analyse the prokaryoplankton community structure and to distinguish between active and “less active” microbial fractions. Our results showed that the rRNA-derived bacterial libraries seemed to be more depth specific compared to 16S rDNA-derived counterparts. Major differences were detected between the active fractions of bacterioplankton thriving in photic (25 m, MAW) and aphotic layers (500–3000 m, LIW and TDW respectively), whereas no statistically-significant differences were detected within the deep, aphotic layers (500–3000 m, LIW and TDW). Archaeal communities possessed more depth-specific distribution patterns with both total and active fractions showing depth stratification. Cyanobacteria and Marine Group II MAGII of Euryarchaea dominated the MAW prokaryoplankton. A notable fraction of Geitlerinema-related cyanobacteria was detected among the metabolically-active bacterial population recovered from the mesopelagic (500 m, LIW) aphotic layer, which is indicative of their mixotrophic behaviour. Heterotrophic Gammaproteobacteria and members of Marine Group 1.1a and the PSL12-related ALOHA group of Thaumarchaeota were both abundant in the aphotic layers (both LIW and TDW). Discrepancies observed between 16S rDNA- and 16S rRNA-based libraries are most likely linked to different physiological states of the prokaryoplankton community members recovered from different layers. Taking into account the relative homogeneity of the main physicochemical parameters throughout the whole water column, light and energy source are likely the most relevant environmental variables shaping microbial biodiversity through the Station Vector water column.

The ectoparasite communities of two juvenile Diplodus species, D. sargus and D. puntazzo , were studied in a rocky coast of the Central Tyrrhenian sea (Mediterranean Sea) where three neighbouring nursery areas showed a differential availability of microhabitats due to a gradual protection gradient capable of influencing local hydrodynamic conditions. Five parasite forms were detected on juvenile hosts: Peniculus fistula , the two larval forms of gnathiids (praniza and zuphea stages), Caligus sp. and Anilocra physodes . Among these species an increasing rates of infestation (up to 57%), from the less protected to the most sheltered site, was detected. The largest infestation rate occurred in the most enclosed site, where P. fistula was the most infective species, also capable of affecting the body condition of juvenile fishes. In addition, to investigate behavioural processes among infected fish, both gut content analyses and in situ HD video sequences were used. Our results demonstrate that ectoparasites cannot be considered as accidental food items, implying an active removal of parasites among conspecifics. The highest frequencies of cleaning interactions were recorded during high ambient light conditions, suggesting the role of visual displays as an important factor in stimulating cleaning interactions. [ABSTRACT FROM AUTHOR]

The METYSS project ( M essinian E vent in the T yrrhenian from S eismic S tudy) is based on high-resolution seismic data acquired along the Eastern Sardinian margin, Western Tyrrhenian Sea. The main aim is to study the Messinian Salinity Crisis (MSC) in the Western Tyrrhenian Basin, but we also investigated the thinning processes of the continental crust and the timing of crustal vertical movements across this backarc domain. Our first results shown that rifting ended before the MSC, but that crustal activity persisted long after the end of the rifting. This has been particularly observed on the proximal margin, the East-Sardinia Basin, where the Mobile Unit (MU, mobile Messinian salt) is thin or absent. In this study, we examined the distal margin, the Cornaglia Terrace, where the MU accumulated during the MSC and acted as a décollement , thus potentially decoupling the basement from the sedimentary cover. Our observations provide evidence for lateral flow and gravity gliding of the salt and its brittle sedimentary overburden along local basement slopes generated by the post-MSC tilting of some basement blocks formerly generated during the rifting. We also investigated an intriguing wedge-shaped body of MU located in a narrow N-S half graben bounded to the west by a major, east-dipping, crustal normal fault. Classically, one could think that this salt wedge is related to the syn-tectonics deposition of the MU, but we propose an original scenario, in which the post-rift vertical motion of the major fault has been cushioned by lateral flow of an initially tabular salt layer, leaving the supra-salt series apparently unaffected by the crustal motions of the basement. We tested this scenario by comparing natural data and physical (analogue) modelling data. Our results reveal that salt tectonics provides a powerful tool to understand the deep crustal tectonics of the margin and to constrain the timing of vertical motions in the Western Tyrrhenian Basin, results that can be applied to rifted salt-bearing margins worldwide. [ABSTRACT FROM AUTHOR]

ABSTRACT: We study a new marine electromagnetic configuration that consists of a ship‐towed inductive source transmitter and a series of remote electric dipole receivers placed on the seafloor. The approach was tested at the Palinuro Seamount in the southern Tyrrhenian Sea, at a site where massive sulphide mineralization has been previously identified by shallow drilling. A 3D model of the Palinuro study area was created using bathymetry data, and forward modelling of the electric field diffusion was carried out using a finite volume method. These numerical results suggest that the remote receivers can theoretically detect a block of shallowly buried conductive material at up to ∼100 m away when the transmitter is located directly above the target. We also compared the sensitivity of the method using either a horizontal loop transmitter or a vertical loop transmitter and found that when either transmitter is located directly above the mineralized zone, the vertical loop transmitter has sensitivity to the target at a farther distance than the horizontal loop transmitter in the broadside direction by a few tens of metres. Furthermore, the vertical loop transmitter is more effective at distinguishing the seafloor conductivity structure when the vertical separation between transmitter and receiver is large due to the bathymetry. As a horizontal transmitter is logistically easier to deploy, we conducted a first test of the method with a horizontal transmitter. Apparent conductivities are calculated from the electric field transients recorded at the remote receivers. The analysis indicates higher apparent seafloor conductivities when the transmitter is located near the mineralized zone. Forward modelling suggests that the best match to the apparent conductivity data is obtained when the mineralized zone is extended southward by 40 m beyond the zone of previous drilling. Our results demonstrate that the method adds value to the exploration and characterization of seafloor massive sulphide deposits. [ABSTRACT FROM AUTHOR]

High sampling rate (10 Hz) anemometric measurements of the "Wind, Ports, and Sea" monitoring network in the northern Tyrrhenian Sea have been analysed to extract the thunderstorm-related signals and catalogue them into three families according to the different time-scale of each event, subdivided among 10 min, 1, and 10 h events. Their characteristics in terms of direction of motion and seasonality/daily occurrence have been analysed: the results showed that most of the selected events come from the sea and occur from 12:00 to 00:00 UTC during the winter season. In terms of peak wind speed, the strongest events all belonged to the 10 min family, but no systematic correlation was found between event duration and peaks. Three events, each one representative of the corresponding class of duration, have been analysed from the meteorological point of view, in order to investigate their physical nature. According to this analysis, which was mainly based on satellite images, meteorological fields obtained from GFS analyses related to convection in the atmosphere, and lightning activity, the thunderstorm-related nature of the 10 min and 1 h events was confirmed. The 10 h event turned out to be a synoptic event, related to extra-tropical cyclone activity. [ABSTRACT FROM AUTHOR]

Living benthic foraminiferal assemblages were investigated at 22 marine stations in front of the Volturno River mouth (Gulf of Gaeta, central Tyrrhenian Sea), during 3-years survey (2012-2014). The results were compared with the oceanographic data recorded at the same sites, to highlight the ecology of the main dominant species and the relationship between the community structures and the environmental variables (turbidity, dissolved oxygen content, salinity, temperature, and runoff). The living assemblage, analyzed in the top 1 cm of sea floor, was characterized by three dominant species (Ammonia tepida, Bulimina elongata, and Rectuvigerina phlegeri) during all the sampling periods. Correlation analysis identified turbidity, runoff, and oxygen as the main environmental factors influencing living foraminiferal assemblages. Ammonia tepida and Rectuvigerina phlegeri showed opportunistic behaviour in response to turbidity, oxygen, and salinity values. No significant correlation was recorded between Bulimina elongata and the environmental parameters, testifying the capability of this species to adapt to different environmental conditions. The occurrence and distribution of these species provided useful information about coastal dynamics and sediment transport, and our results confirmed them as reliable proxies of coastal water column turbidity and Volturno river basin runoff. [ABSTRACT FROM AUTHOR]

Underwater noise assessment is particularly important in coastal areas where a wide range of natural and anthropogenic sounds generate complex and variable soundscapes. In the last century, the number and size of noise sources has increased significantly, thereby increasing the ocean's background noise. Shipping is the main source of lower-frequency underwater noises (<500 Hz). This research aimed to provide an initial assessment of underwater noise levels in a coastal area of the northern Tyrrhenian Sea (Italy) using short-term recordings. Spatial and temporal variations in the noise level, and the type and number of ships sailing through the port were recorded. A significant correlation was found between ferry boats and sound pressure levels, indicating their role as a prevalent source of low frequency underwater noise in the project area. This research could provide the baseline for implementation of distribution and point-source underwater noise models that are required for sustainable coastal management. [ABSTRACT FROM AUTHOR]

In the present study we provide a paleontological and chronostratigraphic review of the Villafranchian fossiliferous sites of Latium, revising the biochronologic attribution based on their framing within the geodynamic and paleogeographic evolutionary picture for this region. Aimed at this scope, we reconstruct the sedimentary and structural history of the Early Pleistocene marine basins through the review and the regional correlation of published stratigraphic sections and borehole data. Moreover, we combine the chronostratigraphic constraints provided in this study to the near-coast deposits of Gelasian-Santernian age (2.58–1.5 Ma) with the results of a recent geomorphologic study of this area, allowing us to reconstruct a suite of terraced paleo-surfaces correlated with marine isotopic stages 21 through 5. By doing so, we provide further age constraints to the sedimentary and tectonic processes acting on the Tyrrhenian Sea margin in Quaternary times, highlighting a possible different paleogeographic evolution of the southern coastal area where the Middle-Villafranchian type-section of Coste San Giacomo site is located, with respect to the northern sector. [ABSTRACT FROM AUTHOR]

The Vercelli Seamount is an undersea topographic feature of the northern Tyrrhenian Sea which rises from around 2000 m depth to almost the surface (55 m depth). In late spring 2009 the interdisciplinary experiment "Tyrrhenian Seamounts Ecosystems: an integrated study" was conducted around the seamount to investigate its influence on the hydrodynamics and the biogeochemical conditions of the area. As part of this integrated study a Slocum glider was operated around the seamount from 23 to 30 May, 2009 to sample the physical and biogeochemical characteristics of the water column from the sea surface down to 190 m depth. The observations revealed little influence of the seamount of the near-surface circulation and water mass characteristics. They showed, however, slanted sub-mesoscale structures below the thermocline in the southern area of the seamount. These features evidenced in different recorded parameters are approximately compensated in density. [ABSTRACT FROM AUTHOR]

The analyses of water and sediment samples, collected at 24 marine stations in a coastal area (Gulf of Gaeta, central Tyrrhenian Sea) during a three year survey (2012–2014), have improved our knowledge of coccolithophore ecology in the Mediterranean neritic domain. A comparison between the results and the oceanographic data has highlighted the ecology of the considered groups, and quantified the relationship between the community structures and the environmental parameters. The coccosphere concentration measured in the Gulf of Gaeta is extremely variable over the sampling periods (min:64 l −1 ; max:2.4*10 5  l −1 ), and comparable with data from other Mediterranean sites. Placolith-bearing taxa are the dominant group of the living communities. The concentration and distribution of Emiliania huxleyi is controlled by the distance from the coast and the Volturno River runoff. The K-strategist taxa are an important component of the summer nannoplankton in the upper 15 m and in the sediment samples. These taxa are also related to summer oligotrophic warm waters and low turbidity as well. The opportunistic behaviour of Helicosphaera carteri is confirmed and is related to moderately elevated nutrient levels and also tolerance to low salinity and terrigenous input. Nevertheless, our findings raise some questions on the reliability of H. carteri as a low salinity proxy. Overall, the sediment assemblages reflect the composition and the temporal distribution of the living communities. The occurrence and distribution of abundant reworked coccoliths, both in water and sediments, provides useful information about coastal dynamics and confirm their use as a reliable runoff proxy. [ABSTRACT FROM AUTHOR]

The new record of a shallow-water submarine hydrothermal field (<150 m w.d.) in the western Mediterranean Sea (Tyrrhenian Sea, Italy) allows us to study CO 2 fluid impact on benthic foraminifers. Benthic foraminifers calcification process is sensitive to ocean acidification and to local chemical and physical parameters of seawater and pore water. Thus, foraminifers can record specific environmental conditions related to hydrothermal fluids, but at present their response to such activity is poorly defined. The major outcome of this study is the finding of a very uncommon taxon for the Mediterranean Sea, i.e., the Spiculosiphon oceana , a giant foraminifer agglutinating spicules of sponges. This evidence, along with the strong decrease of calcareous tests in the foraminiferal assemblages associated to hydrothermal activity, provides new insights on the meiofauna living in natural stressed environment. In particular, observations obtained from this study allow us to consider S. oceana a potential tolerant species of high CO 2 concentrations (about 2–4 times higher than the normal marine values) and a proxy of acidic environments as well as of recent ocean acidification processes. [ABSTRACT FROM AUTHOR]

In the context of transferable fishing concessions, the most well-known tool is probably the individual transferable quota, whereas the case of individual transferable effort quotas (ITEs) is much less often discussed. This study is the result of a project realized in collaboration with Italian fishery associations with the objective of evaluating, in a participatory framework, the possible consequences of the introduction of ITEs. A semi-quantitative survey was carried out over a sample of key stakeholders being experts of bottom trawling fisheries in the Tyrrhenian and Adriatic Seas and the pelagic trawling fishery in the Adriatic Sea. The results and elaborations of the surveys were discussed and validated by a focus group composed of delegates of fishery associations. Two aspects were investigated: the relationships between fishing capacity (i.e. engine power and gross tonnage), fishing activity (i.e. fishing days and fishing hours), revenues, and variable costs (e.g. fuel) and the suitability of different proposals and alternative approaches for the introduction of ITEs. The participation of stakeholders allowed the building of some simple pedagogical tools based on realistic figures collected through the surveys that could be used by managers of associations, cooperatives, and producer organizations to better understand the functioning and possible consequences of ITEs schemes. [ABSTRACT FROM AUTHOR]

Abstract: The structural complexity of back‐arc basins is related to the evolution of the associated subduction system. Here, we present an integrated geophysical and geological study that constrains the 3D spatial variability of magmatic activity along the Tyrrhenian back‐arc basin. We use wide‐angle seismic and gravity data, acquired in 2010 within the MEDOC experiment along a ~300 km‐long NW‐SE transect that extends from SE Sardinia Island to the NW Sicily continental margin, across the Cornaglia Terrace. The geophysical transect is coincident with a seismic reflection line from the Italian CROP experiment that we have re‐processed. The geophysical results, together with available basement dredges, support a basement along the profile fundamentally composed of continental‐type rocks, locally affected by subduction‐related magmatism. The continental nature of this region contrasts with the nature of the basement inferred along two geophysical cross‐sections located to the north of the Cornaglia Terrace in which seismic velocity of the lower crust supports significant magmatic crustal accretion. The comparison of these three cross‐sections supports that the highest magmatic activity occurred in the central and most extended region of the basin, whereas it was less important in the North and practically nonexistent in the South. These observations indicate abrupt variations of magmatism during the basin formation. As in other back‐arcs, the temperature, water content and composition of the mantle might have played an important role in such variation, but they fail to explain the abruptness of it. We propose that the interaction of the overriding continental lithospheres of Adria and Africa with the Apenninic‐Calabrian subduction system caused changes in slab rollback and trench retreat dynamics, which in turn resulted in variations of back‐arc stretching and magmatism. Based on our observations, we suggest that the Cornaglia Terrace formation process might share some similarities with the formation of oceanic crust in the Red Sea. [ABSTRACT FROM AUTHOR]

In this paper, we present the results of an ~5-h airborne gamma-ray survey carried out over the Tyrrhenian Sea in which the height range (77-3066) m has been investigated. Gamma-ray spectroscopy measurements have been performed using the AGRS_16L detector, a module of four 4L NaI(Tl) crystals. The experimental setup was mounted on the Radgyro, a prototype aircraft designed for multisensorial acquisitions in the field of proximal remote sensing. By acquiring high-statistics spectra over the sea (i.e., in the absence of signals having geological origin) and by spanning a wide spectrum of altitudes, it has been possible to split the measured count rate into a constant aircraft component and a cosmic component exponentially increasing with increasing height. The monitoring of the count rate having pure cosmic origin in the >3-MeV energy region allowed to infer the background count rates in the 40K, 214Bi, and 208Tl photopeaks, which need to be subtracted in processing airborne gamma-ray data in order to estimate the potassium, uranium, and thorium abundances in the ground. Moreover, a calibration procedure has been carried out by implementing the CARI-6P and Excel-based program for calculating atmospheric cosmic ray spectrum dosimetry tools, according to which the annual cosmic effective dose to human population has been linearly related to the measured cosmic count rates. [ABSTRACT FROM AUTHOR]

The geological, biological and geochemical features of a particular field of hydrothermal vents, discovered in the Panarea Volcanic Complex during a research survey carried out in 2015, are described for the first time. The site, located at 70–80 m depth off the South-western coast of the islet of Basiluzzo, was named Smoking Land for the presence of a large number of wide and high active chimneys and was characterized in terms of dissolved benthic fluxes, associated macrofauna and megafauna communities and preliminary mineralogy and geochemistry of chimney structures. On the whole field, a total of 39 chimneys, different in size and shape, were closely observed and described; 14 of them showed emission of low temperature hydrothermal fluids of marine origin characterized by acidified chemical conditions. The CTD and benthic chamber measurements highlighted that the Smoking Land is able to form a sea water bottom layer characterized by variable acidity and high DIC and trace elements concentrations; these characteristics weaken moving away from the chimney mouths. The SEM-EDS analysis of the collected solid samples revealed a chimney structure principally composed by amorphous and low crystalline Fe-oxyhydroxides of hydrothermal origins. The ROV explorations revealed a wide coverage of red algae (Peyssonnelia spp.) colonized by the green algae Flabiella petiolata and by suspension feeders, mainly sponges, but also bryozoans, and tubicolous polychaetes. Although novent-exclusive species were identified, the benthic communities found in association to the chimneys included more taxa than those observed in the surrounding no-vent rocky areas. These first findings evidence a submarine dynamic habitat where geological, chemical and biological processes are intimately connected, making the Smoking Land an important site in terms of marine heritage that should be safeguarded and protected. [ABSTRACT FROM AUTHOR]

Biogenic formations, built up by the sessile and gregarious vermetid gastropod Dendropoma cristatum , were studied from June to October 2014 along the rocky shores of Licosa islet (Gulf of Salerno, Tyrrhenian Sea), where they build up the northernmost reefs in the Mediterranean Sea in order to shed light on possible latitudinal changes. The islet has two differently exposed sides, with three types of vermetid formations: the first consists in a thin layer composed by vermetid gastropods and the coralline alga N. brassica-florida , widespread only in the sheltered side of the islet; the second is represented by small isolated pillows (13.9 ± 5.64 cm), all around the islet at depth of more than fifteen centimetres; the third is a well-structured reef, characterized by a dense layer of mollusc shells that overgrow each other, only found in the exposed side of the islet. The vermetid reef was monitored in two sites with different substrates: ancient walls, made of calcareous lateritious material, and the flysch rocks, composed by siliceous turbiditic deposits. While no differences arise in gastropod density related to rock type (calcareous lateritious material versus siliceous turbiditic deposits), significant differences have been found along a vertical gradient, seeing density increases from the upper intertidal to the upper subtidal level. The associated algal cover seems to be inversely related to the vermetid density. In the upper intertidal, D. cristatum was almost completely covered (about 83%) by a thick layer of encrusting alga N. brassica-florida . In the lower intertidal the encrusting alga disappear but the shells of vermetid gastropods were remarkably colonized by the erected red algae of the “ Laurencia complex” (70%) while in the upper subtidal, the vermetid shells were scarcely covered, mainly by other algal species (13%). By comparing present data with those of Sicilian reefs no evidences arise due to the different latitude. Innovative approaches (Remotely Piloted Aircraft Systems technology and fractal geometry) applied to these marine bioconstructions, resulted very effective in mapping and structuring the complexity of the reefs. [ABSTRACT FROM AUTHOR]

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In this paper we present and discuss data concerning the morphostructural evolution at Ustica Island (Tyrrhenian Sea, Italy) during Late Quaternary. New insights on the relative sea-level changes of Ustica are coming from data collected during a geomorphological field survey around the island, together with the bathymetric analysis of the surrounding seabed and 14 C datings on samples of speleothems, flowstones and marine shells found inside three selected sea caves. The survey was mainly accomplished on June 2015 through the first complete snorkel investigation off the about 18 km-long volcanic coast of the island, which allowed to precisely define location, relationship and morphometric features of coastal landforms associated with modern sea level. This study highlights the occurrence, for the first time in the Mediterranean, of tidal notches in correspondence of carbonate inclusions in volcanic rocks. The elevation of the modern tidal notch suggests that no significant vertical deformations occurred in the southeastern and eastern sectors of Ustica in the last 100 years. However, the presence of pillow lavas along the coast demonstrates that Ustica was affected by a regional uplift since the Late Quaternary, as also confirmed by MIS5.5 deposits located at about 30 m a.s.l., which suggests an average uplift rate of 0.23 mm/y. Radiocarbon dating of fossil barnacles collected inside the Grotta Segreta cave indicate an age of 1823 ± 104 cal. BP. The difference in height with respect to living barnacles in the same site suggests that their present elevation could be related to stick-slip coseismic deformations caused by the four earthquake sequences (two of which with M w = 4.63 ± 0.46) that strongly struck the island between 1906 and 1924. [ABSTRACT FROM AUTHOR]

This paper provides the first report of the leech, Pontobdella muricata (Linnaeus, 1758), in the Tyrrhenian Sea. The leech was found on the brown ray, Raja miraletus (Linnaeus 1758), and on the spotted ray, Raja montagui (Fowler, 1910), caught by trawling during autumn 2014. Complete sequence of 18S rRNA gene, COI mitochondrial gene and partial sequences of the mitochondrial 12S rRNA gene corroborate the determination based on morphological characteristics. [ABSTRACT FROM AUTHOR]

A brief review of the published evidence of current deposits around Italy is the occasion to test the robustness of matching bottom current velocity models and seafloor morphologies to identify contourite drifts not yet documented. We present the result of the regional hydrodynamic model MARS3D in the Northern Tyrrhenian and Ligurian Sea with horizontal resolution of 1.2 km and 60 levels with focus on bottom current: data are integrated over summer and winter 2013 as representative of low and high intensity current conditions. The Eastern Ligurian margin is impacted by the Levantine Intermediate Water (LIW) with modeled mean velocity of bottom current up to 20 cm s −1 in winter 2013 and calculated bottom shear stress exceeding 0.2 N m −2 in water depth of 400–800 m. By crossing this information with seafloor morphology and geometry of seismic reflections, we identify a sediment drift formerly overlooked at ca 1000 m water depth. The Portofino separated mounded drift has a maximum thickness of at least 150 m and occurs in an area of mean current velocity minimum. Independent evidence to support the interpretation include bottom current modelling, seafloor morphology, seismic reflection geometry and sediment core facies. The adjacent areas impacted by stronger bottom currents present features likely resulted from bottom current erosion such as a marine terrace and elongated pockmarks. Compared to former interpretation of seafloor morphology in the study area, our results have an impact on the assessment of marine geohazards: submarine landslides offshore Portofino are small in size and coexist with sediment erosion and preferential accumulation features (sediment drifts) originated by current-dominated sedimentary processes. Furthermore, our results propel a more general discussion about contourite identification in the Italian seas and possible implications. [ABSTRACT FROM AUTHOR]

We use seismic oceanography to document and analyze oceanic thermohaline fine structure across the Tyrrhenian Sea. Multichannel seismic (MCS) reflection data were acquired during the MEDiterranean OCcidental survey in April-May 2010. We deployed along-track expendable bathythermograph probes simultaneous with MCS acquisition. At nearby locations we gathered conductivity-temperature-depth data. An autonomous glider survey added in situ measurements of oceanic properties. The seismic reflectivity clearly delineates thermohaline fine structure in the upper 2,000 m of the water column, indicating the interfaces between Atlantic Water/Winter Intermediate Water, Levantine Intermediate Water, and Tyrrhenian Deep Water. We observe the Northern Tyrrhenian Anticyclone, a near-surface mesoscale eddy, plus laterally and vertically extensive thermohaline staircases. Using MCS, we are able to fully image the anticyclone to a depth of 800 m and to confirm the horizontal continuity of the thermohaline staircases of more than 200 km. The staircases show the clearest step-like gradients in the center of the basin while they become more diffuse toward the periphery and bottom, where impedance gradients become too small to be detected by MCS. We quantify the internal wave field and find it to be weak in the region of the eddy and in the center of the staircases, while it is stronger near the coastlines. Our results indicate this is because of the influence of the boundary currents, which disrupt the formation of staircases by preventing diffusive convection. In the interior of the basin, the staircases are clearer and the internal wave field weaker, suggesting that other mixing processes such as double diffusion prevail. [ABSTRACT FROM AUTHOR]