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Intracellular parasites of the genus Glugea Thélohan, 1891 (Microsporidia) comprise about 34 putative species capable of causing high morbidity and mortality in freshwater and marine teleost fishes. In this study, we report on the first mass mortality event associated with Glugea sp. infecting free‐ranging round sardinella Sardinella aurita in the southern Tyrrhenian Sea (Italy). Here, we describe the ultrastructure of mature spores of this microsporidian and characterize it molecularly, as well as report its phylogenetic position. Most of the affected fish showed an irregular swelling of its abdomen. At necropsy, a variable number of xenomas, spherical to ellipsoidal in shape, were found in the peritoneal cavity strongly attached to the viscera of all fish. Histological analysis revealed varying severity of chronic inflammation along with occasional necrosis in visceral organs associated with multiple xenoma proliferation. These pathological findings were considered the main cause of this mass mortality event. Morphologically, the present material was closely related to G. sardinellesis and G. thunni. The phylogenetically closest taxa to the newly SSU rDNA sequence were G. thunni and an erroneusly identified G. plecoglossi, which were very closely related to each other, also suggesting that all these sequences might belong to the same species. [ABSTRACT FROM AUTHOR]

The warming trend of the Mediterranean region is already well known, but there is still a lack of information on its seasonal/annual to multidecadal time scales and its distribution in all water masses, including deep water. New temporal and spatial evidence of this thermal variability has been presented in the Tyrrhenian Sea, thanks to twenty-year continuous monitoring by eXpendable BathyThermographs (XBTs) along a fixed route from Genoa to Palermo. The Tyrrhenian Sea is one of the deepest Mediterranean sub-basins (with a maximum depth of about 4000 m), but its interaction with neighbouring basins is controlled by topographical factors, such as the Sardinian Channel to the south and the Corsican Channel to the north. The way in which the warm signal, originating from the Levantine sub-basin, and entering from the south, affects the entire Tyrrhenian Basin spreading rapidly northwards is studied, considering its peculiarities, such as topography, surface circulation, and strong stratification, as well as its climate variability. The warming trend observed for the Tyrrhenian Sea is consistent with the trend for the Mediterranean Sea as a whole. However, the Tyrrhenian Sea shows some peculiar features: around 2014, a shift to a new equilibrium (warmer) state was detected, with mean values along the monitored route that were significantly higher than the previous period (from 1999 to 2013), especially for the subsurface level, from 100 to 450 m depth. [ABSTRACT FROM AUTHOR]

We perform a joint analysis of gravity and magnetic data sets in the Tyrrhenian Sea region to infer the rock physical properties of several volcanic seamounts. We propose a moving‐window application using Poisson's theorem, which relates the total gradient of the magnetic field to the total gradient of the first‐order vertical derivative of the gravity field data. In volcanic environments, where strong intensity of remanent magnetization is expected, the total gradient of the magnetic field is particularly useful since it is almost independent on the direction of the total‐magnetization. The moving‐window approach resulted necessary due to the heterogeneous magnetization distribution of the volcanoes. First, we perform synthetic tests based on realistic seamount models which exhibit inhomogeneous magnetization intensity and orientation. Using the total gradients, we demonstrate that our approach can provide an appropriate magnetization‐to‐density ratio in different subareas of seamounts. The results of the correlation analysis for the Palinuro, Marsili, Vavilov, and Magnaghi seamounts provide interesting information on the variability of magnetization associated with different epochs of formation and demagnetization effects due to hydrothermal alteration processes. Plain Language Summary: We analyzed gravity and magnetic data sets to determine the rock properties of the main seamounts in Southern Tyrrhenian Sea. This study shows that the correlation analysis based on a window‐by‐window approach is an efficient tool for studying potential field anomalies in areas where inhomogeneous distribution of magnetization is expected. We also show that, by studying the total gradients of the magnetic field and the first order vertical derivative of the gravity field, the correlation analysis is almost insensitive to the direction of the remanent magnetization. We obtain interesting information on the variability in magnetization for each seamount and identify possible areas of demagnetization due to hydrothermal alteration processes. Key Points: We may infer the rock magnetization of seamounts by the correlation analysis of gravity and magnetic anomaliesThe study of the potential field total gradients is particularly useful when the source has strong remanent magnetizationWe found inhomogeneous magnetization in the Palinuro, Marsili, Magnaghi and Vavilov seamounts, likely due to hydrothermal activity [ABSTRACT FROM AUTHOR]

Secchi-disk is an instrument that enables investigating water transparency, being reflective of sunlight to be used to measure the depth of light penetration in the water column. In biological marine research, the device is used to determine the intensity of primary production of planktonic algae. In the present study, we reevaluated the practicality of Secchi's method, developed some 160 years ago, for modern oceanography by using the same locations, methods, objectives, and comparable Secchi disk that were used in his survey in 1865. We show that the Secchi-disk is still a valid scientific method in environmental marine research and therefore defends its place reliably among modern electronical research infrastructure. Observer's subjectivity didn't have a significant effect on measuring but environmental conditions can influence ZSD determination in general. It is therefore justified to follow, for example, the general recommendations for the use of the Secchi net issued by HELCOM. Our results also revealed that ZSD was located about twofold deeper in 1865 than presentlywhich cannot be explained only by annual variation.We show that green(ish) sea areas have today extended to larger sea areas than they were 160 years ago, due to an increase in the turbidity of the water resulting from, e.g., general eutrophication. [ABSTRACT FROM AUTHOR]

Some seismo-stratigraphic evidence on the occurrence of wave-cut marine terraces in the Licosa promontory (Southern Tyrrhenian Sea, Italy) based on Sub-bottom Chirp seismic sections is herein presented. Such evidence is provided by marine terraced surfaces situated at various water depths below sea level and etched into the rocky acoustic basement, which are extensively extending in the seaward extension of the Licosa promontory. It is possible that the isotopic stratigraphy and the terraced marine surfaces are connected, so they can be attributed and dated indirectly. The geologic study of seismic profiles has pointed to the prominence of the acoustic basement, extending to the seabed close to the coast and subsiding seawards under the Quaternary marine succession. Ancient remains of marine terraces, found at a range of water depths between 5 m and 50 m, have documented the major morphological changes of the acoustic basement during the Late Quaternary. [ABSTRACT FROM AUTHOR]

Copepods dominate marine zooplankton in abundance and play key roles in pelagic food webs. These small crustaceans show high taxonomic and functional diversity. Although there has been considerable research on their taxonomy, only a few studies have focused on their functional traits. In this study, we analyzed the functional traits of 95 copepod species, considering their body size, trophic regime, feeding behavior, and spawning strategy. Based on samples collected during two surveys (autumn 2020 and summer 2021) located in the coastal waters of three gulfs (Gaeta, Naples, and Salerno) in the highly populated Campania region (the central Tyrrhenian Sea, NW Mediterranean), we identified nine functional groups of copepods with different characteristics. The group that comprised herbivorous copepods with feeding currents and a broadcast strategy was the most abundant in both seasons and all gulfs. This group was dominated by Acartia clausi, Centropages typicus, Temora stylifera, and the Paracalanus parvus complex. The other functional groups showed differences in their temporal and spatial distribution. Our study reports the functional diversity of copepods along the Campania coast, thus contributing to advancing our knowledge of the planktonic trophic structure in a region of considerable importance due to its marine resources and services. [ABSTRACT FROM AUTHOR]

Philometroides Yamaguti, 1935 is a genus of dracunculoid nematodes of the family Philometridae Baylis & Daubney, 1926 comprising tissue-infecting species worldwide. In the present study, a new species of Philometroides is described from the Tyrrhenian Sea (central-western Mediterranean Sea) using integrative approaches such as light and scanning microscopy, histopathology and 18S rRNA sequencing. Philometroides giginosantoroi n. sp. found in the skeletal muscles of the Mediterranean moray Muraena helena can be distinguished from its congeners by a combination of morphological traits and in particular by having the oral aperture with 3 large sclerotized triangular oesophageal teeth. The molecular analyses and phylogenetic reconstructions support its status as a new taxon and placed it within a clade of tissue-infecting species, although also confirmed mismatches in the generic assignment of several species. Philometroides giginosantoroi n. sp. is the second species of the genus found in the Mediterranean Sea and in general in the European marine waters and the third species of the family known to infect the family Muraenidae.

In this paper, we describe the geohazard-related elements of the Eastern Tyrrhenian Sea continental margin, situated between the 40° and 41° North latitude. These features were recognised principally through morphological analysis. The investigation utilized medium – and high-resolution digital models of the submarine landscape, produced within the framework of the Magic project (Marine Geohazard along Italian Coasts), and primarily focusing on the bathymetric range of 50–700 meters. The surveyed area encompasses a recently formed continental margin, which connects the internal segments of the Apennine fold-and-thrust belt, verging NE, to the Tyrrhenian Sea bathyal plain, a 3000-m-deep back-arc basin that has developed since the Middle-Late Miocene. Several classes of hazard-related elements have been identified offshore, primarily associated with high-gradient slopes and a large number of volcanic edifices and banks. These include canyon systems, erosive scarps, landslide complexes, fault – and volcanic-related features, such as the products of the volcanic edifices instability, which claim to varying degrees of geo-hazard. Additionally, bedforms, fluid seepages and creeping phenomena in the prodelta slopes suggest high morpho-tectonic and environmental dynamics.HighlightsThis article reports on the thematic maps developed along the Lazio – Campania offshore (Central-eastern Tyrrhenian Sea, Italy) within the framework of the Magic Project, based on geomorphological analysis of the HR Digital Elevation Model of the seafloor.Several classes of hazard-related elements have been identified offshore, mainly associated with high-gradient slopes, volcanic activity and intense morphodynamic processes.The entire suite of maps created in the context of the Magic Project serves as a valuable base of knowledge, extending to the national scale and benchmarks for future monitoring of critical sites and geo-hazard-related features, as well as for maritime spatial planning actions.

During underwater monitoring, one specimen of Camachoaglaja africana and one of Biuve fulvipunctata were found at the ‘Tavolara Punta Coda Cavallo’ Marine Protected Area, allowing to expand the known Mediterranean range of distribution of these two species. The finding of both species constitutes the first report for NE Sardinia and the whole Tyrrhenian Sea. By coupling data obtained from the analysis of social media and those present in the bibliography it was also possible to speculate on alternative pattern of distribution of these two species at a global scale. Finally, it is also confirmed the importance of repeated monitoring activities over time on the mooring buoys which act as steppingstone habitats for epifauna or for larval settlement and that are capable to provide important additional information on local biodiversity.

Secchi-disk is an instrument that enables investigating water transparency, being reflective of sunlight to be used to measure the depth of light penetration in the water column. In biological marine research, the device is used to determine the intensity of primary production of planktonic algae. In the present study, we re-evaluated the practicality of Secchi’s method, developed some 160 years ago, for modern oceanography by using the same locations, methods, objectives, and comparable Secchi disk that were used in his survey in 1865. We show that the Secchi-disk is still a valid scientific method in environmental marine research and therefore defends its place reliably among modern electronical research infrastructure. Observer’s subjectivity didn’t have a significant effect on measuring but environmental conditions can influence ZSD determination in general. It is therefore justified to follow, for example, the general recommendations for the use of the Secchi net issued by HELCOM. Our results also revealed that ZSD was located about twofold deeper in 1865 than presently which cannot be explained only by annual variation. We show that green(ish) sea areas have today extended to larger sea areas than they were 160 years ago, due to an increase in the turbidity of the water resulting from, e.g., general eutrophication.

The warming trend of the Mediterranean region is already well known, but there is still a lack of information on its seasonal/annual to multidecadal time scales and its distribution in all water masses, including deep water. New temporal and spatial evidence of this thermal variability has been presented in the Tyrrhenian Sea, thanks to twenty-year continuous monitoring by eXpendable BathyThermographs (XBTs) along a fixed route from Genoa to Palermo. The Tyrrhenian Sea is one of the deepest Mediterranean sub-basins (with a maximum depth of about 4000 m), but its interaction with neighbouring basins is controlled by topographical factors, such as the Sardinian Channel to the south and the Corsican Channel to the north. The way in which the warm signal, originating from the Levantine sub-basin, and entering from the south, affects the entire Tyrrhenian Basin spreading rapidly northwards is studied, considering its peculiarities, such as topography, surface circulation, and strong stratification, as well as its climate variability. The warming trend observed for the Tyrrhenian Sea is consistent with the trend for the Mediterranean Sea as a whole. However, the Tyrrhenian Sea shows some peculiar features: around 2014, a shift to a new equilibrium (warmer) state was detected, with mean values along the monitored route that were significantly higher than the previous period (from 1999 to 2013), especially for the subsurface level, from 100 to 450 m depth.

Knowledge of post-larval swordfish (Xiphias gladius) ecology in the world's oceans is incomplete as they are rarely found in ichthyoplankton samplings or commercial catches and individuals are difficult to observe in the marine ecosystem. Analyses of stomach contents of apex predators can provide otherwise unobtainable ecological insights. Two well-preserved bills of post-larval swordfish were identified among the partially digested stomach contents of an adult male dolphinfish (Coryphaena hippurus) caught in the northern Tyrrhenian Sea. The lower jaw to fork lengths of the two predated swordfish were estimated at, respectively, 18 and 22 cm, corresponding to 81- and 99-day-old swordfish hatched in the 2022 spawning season. This analysis and recent information on the reproductive dynamics of swordfish in the same area reported in the literature shed light not only on the early stages of swordfish growth but also on dolphinfish ecology in the Tyrrhenian Sea. The two species share the same habitat and are both caught with commercial pelagic surface longlines. Environmental shifts associated with climate change could unpredictably modify the reproduction dynamics, growth, recruitment and distribution of both species. This knowledge is important for the sustainable management of regional fisheries. [ABSTRACT FROM AUTHOR]

The recent article of Loreto et al. (2021) reported new stratigraphic and structural data of the Tyrrhenian backarc basin and used them to propose a new model of crustal architecture of the basin including oceanic sectors. However, we want to open a discussion on the inconsistencies between the interpreted tectonic structures, as well as the age of faults and the data observations. In particular, data analyses and interpretations of the authors do not fully support the structural and isopach maps and models presented. Furthermore, the authors have not discussed previous published data/interpretations on timing and structural style of the rifting of the region. [ABSTRACT FROM AUTHOR]

This study documents the presence of Hypleurochilus bananensis in a new area within the Tyrrhenian Sea, located about 30 km south of the closest occurrence locality known to date. Providing novel insights into its habitat, the observations here reported, at “Caterina Beach” (Sant’Agnello) on 29th and 30th December 2023, revealed the presence of four individuals close to a port beach area, in an artificial habitat represented by rusted iron pipes. These findings contribute valuable data to the limited knowledge on this rare species, providing new distributional and habitat notes.

Abstract Marine biodiversity stewardship requires costly and time‐consuming capture‐based monitoring techniques, which limit our understanding of the distribution and status of marine populations. Here, we reconstruct catch and demersal community composition in a set of 24 fishing sites in the central Tyrrhenian Sea by gathering environmental DNA (eDNA) aboard commercial bottom‐trawl fishing vessels. We collected genetic material from two sources: the water draining from the net after the end of hauling operations (“slush”), and custom‐made rolls of gauze tied to a hollow perforated sphere placed inside the fishing net (“metaprobe”). Species inventories were generated using a combination of fish‐specific (Tele02 12S) and universal metazoan (COI) molecular markers. DNA metabarcoding data recovered over 90% of the caught taxa and accurately reconstructed the overall structure of the assemblages of the examined sites, reflecting expected differences linked to major drivers of community structure in Mediterranean demersal ecosystems, such as depth, distance from the coast, and fishing effort. eDNA also returned a “biodiversity bonus” mostly consisting of pelagic species not catchable by bottom trawl but present in the surrounding environment. Overall, the “metaprobe” gauzes showed a greater biodiversity detection power as compared to “slush” water, both qualitatively and quantitatively, strengthening the idea that these low‐cost sampling devices can play a major role in upscaling the gathering of data on both catch composition and the broader ecological characteristics of marine communities sustaining trawling activities. This approach has the potential to drastically expand the reach of ecological monitoring, whereby fishing vessels operating across the oceans may serve as opportunistic scientific platforms to increase the strength and granularity of marine biodiversity data.

We integrate 10 new with five published 40Ar/39Ar age determinations, both on primary volcanic deposits and on detrital sanidine, which provide precise geochronologic control on the Marine Isotope Stage (MIS) 5.5 and MIS 5.3 sea‐level indicators that occur at three coastal caves in a tectonically stable region of the central Tyrrhenian Sea of Italy. The age of a Strombus‐bearing bioclastic conglomerate, associated with a tidal notch occurring at 9.5 m a.s.l. at Cape Circeo, is constrained to between 121.5 ± 5.8 and 116.2 ± 1.2 ka. Moreover, backbeach deposits intercalated in the sedimentary filling of Guattari and Capre coastal caves are directly correlated with a tidal notch at ∼2.5 m associated with another bioclastic conglomerate at Cape Circeo and dated to 110.4 ± 1.4–104.9 ± 0.9 ka. The latter deposit is also correlated with the adjacent marine terrace, occurring at 3–5 m on the coast between Capes Circeo and Anzio, for which a maximum age of 100.7 ± 6.6 ka was previously reported. These data provide evidence for a maximum sea level around 9.5 m above the present sea level and a duration of MIS 5.5 highstand until 116 ka, in agreement with estimates from other regions in the world. In contrast, they suggest a maximum sea level during MIS 5.3 highstand that is similar to the present level, and only ∼7 m lower than the MIS 5.5 highstand, challenging the reconstructions of the MIS 5 ice‐sheet volumes and derived global sea levels that are based on benthic oxygen isotope records. Key Points: We present 10 40Ar/39Ar ages on the Marine Isotope Stage (MIS) 5.5 and MIS 5.3 sea‐level indicators on the Tyrrhenian Sea coastMIS 5.5 paleo‐sea level at ∼9.5 m a.s.l. is dated 121.5 ± 5.8 through 116.2 ± 1.2 kaWe find a MIS 5.3 sea level ca. 20 m higher than the δ18O‐derived values [ABSTRACT FROM AUTHOR]

Copepods dominate marine zooplankton in abundance and play key roles in pelagic food webs. These small crustaceans show high taxonomic and functional diversity. Although there has been considerable research on their taxonomy, only a few studies have focused on their functional traits. In this study, we analyzed the functional traits of 95 copepod species, considering their body size, trophic regime, feeding behavior, and spawning strategy. Based on samples collected during two surveys (autumn 2020 and summer 2021) located in the coastal waters of three gulfs (Gaeta, Naples, and Salerno) in the highly populated Campania region (the central Tyrrhenian Sea, NW Mediterranean), we identified nine functional groups of copepods with different characteristics. The group that comprised herbivorous copepods with feeding currents and a broadcast strategy was the most abundant in both seasons and all gulfs. This group was dominated by Acartia clausi, Centropages typicus, Temora stylifera, and the Paracalanus parvus complex. The other functional groups showed differences in their temporal and spatial distribution. Our study reports the functional diversity of copepods along the Campania coast, thus contributing to advancing our knowledge of the planktonic trophic structure in a region of considerable importance due to its marine resources and services.

Coastal areas are extremely exposed to litter pollution. In this work, we assessed the abundance and distribution of microlitter in the water column and surface waters, as well as its summertime transport trajectories in the northern Latium coastal area (Tyrrhenian Sea, Italy). Microlitter items were classified according to their different shapes (fragments, films, and filaments), sizes, colours, and types by visual sorting and by optical microscopy; their composition was addressed via spectroscopic (Raman and FTIR) microanalysis. Microplastics (MPs) were abundant in all water samples; polypropylene, polyethylene, and poly-methyl methacrylate were identified. The results show a higher concentration of microlitter items in the water column (average concentration of 5.9 ± 1.38 items/m³) compared to surface waters (average concentration of 0.16 ± 0.03 items/m³). These abundances are similar to those found in the Mediterranean Sea and Oceanic waters. The sampling sites closer to the coast showed a higher abundance of particles, especially filaments, in the water column compared to the offshore areas. This feature can be explained based on the presence of land-based pollution sources, bathing areas, and the resuspension of microlitter items from the bottom. Analysis of the surficial trajectories pointed to a general northward transport direction of microlitter and the presence of possible enrichment spots along the coast.

In recent years, the introduction of alien and invasive marine species in the Mediterranean Sea has rapidly increased. Laonome triangularis is a sabellid worm, native to the Australian coasts. Its first record in the Mediterranean Sea dates back to 2009 and, in this area, it is currently labeled as an allochthonous species. In the present work, we report the fìrst record of this polycheate in Italian waters and we provide some diagnostic features that are useful to identify the species. [ABSTRACT FROM AUTHOR]

Varunaivibrio sulfuroxidans type strain TC8T is a mesophilic, facultatively anaerobic, facultatively chemolithoautotrophic alphaproteobacterium isolated from a sulfidic shallow-water marine gas vent located at Tor Caldara, Tyrrhenian Sea, Italy. V. sulfuroxidans belongs to the family Thalassospiraceae within the Alphaproteobacteria, with Magnetovibrio blakemorei as its closest relative. The genome of V. sulfuroxidans encodes the genes involved in sulfur, thiosulfate and sulfide oxidation, as well as nitrate and oxygen respiration. The genome encodes the genes involved in carbon fixation via the Calvin–Benson–Bassham cycle, in addition to genes involved in glycolysis and the TCA cycle, indicating a mixotrophic lifestyle. Genes involved in the detoxification of mercury and arsenate are also present. The genome also encodes a complete flagellar complex, one intact prophage and one CRISPR, as well as a putative DNA uptake mechanism mediated by the type IVc (aka Tad pilus) secretion system. Overall, the genome of Varunaivibrio sulfuroxidans highlights the organism's metabolic versatility, a characteristic that makes this strain well-adapted to the dynamic environmental conditions of sulfidic gas vents. [ABSTRACT FROM AUTHOR]

The fin whale Balaenoptera physalus is a large rorqual species occurring worldwide, mainly in temperate and subpolar zones. In contrast to many baleen whales, not all the fin whale populations show the same model of migration. In fact, migratory behaviours of this latter species range from long seasonal migration between high and low latitudes to a complete non-migratory behaviour. A resident fin whale population was described in the Mediterranean Sea, which is also frequented by North Atlantic individuals entering through the Strait of Gibraltar in winter to feed. Between 2020 and 2021 three individuals initially identified as fin whales died along the Tyrrhenian coasts (Mediterranean Sea, Italy). Their mitochondrial DNA control region (mtDNA CR) was analysed and compared to fin whale haplotypes previously described in North Atlantic Ocean and Mediterranean Sea to identify their geographical origin. Our results show that two individuals most likely belong to the Mediterranean fin whale population, while an individual was recognised as a putative fin-blue whale hybrid (Balaenoptera physalus x Balaenoptera musculus) with a North Atlantic origin. The discovery of the first fin-blue whale hybrid in the Mediterranean Sea was confirmed by the analysis of a biparentally inherited marker, the α-lactalbumin (α-lac) nuclear gene, demonstrating that the morphological analysis alone does not allow to correctly identify hybrids, especially if intermediate characters of both parental species are not clearly distinguishable.

Cette étude constitue le second signalement du gobie méditerranéen Gobius xoriguer Iglésias, Vukić & Šanda 2021, auparavant uniquement connu à travers sa description originale, et étend sa répartition connue à la mer Adriatique. La récolte dans l'étage bathyal (374 m) de la mer Tyrrhénienne élargit significativement sa répartition bathymétrique. Les spécimens de Vanneaugobius doll-fusi Brownell, 1978 collectés dans la partie ouest de l'Adriatique constituent les premiers signalements de l'espèce pour l'Italie. [ABSTRACT FROM AUTHOR]

Fucales (Phaeophyceae) are ecosystem engineers and forest-forming macroalgae whose populations are declining dramatically. In the Mediterranean Sea, Cystoseira sensu lato (s.l.)—encompassing the genera Cystoseira sensu stricto, Ericaria, and Gongolaria—is the most diverse group, and many species have been shown to be locally extinct in many areas, resulting in a shift toward structurally less complex habitats with the consequent loss of ecosystem functions and services. In this study, we report on the extensive occurrence of healthy and dense marine forests formed by Fucales in the Santa Maria di Castellabate Marine Protected Area in Cilento, Italy (Tyrrhenian Sea, Mediterranean). On a total area of 129.45 ha, 10 Cystoseira s.l. taxa were detected using a combined morphological and molecular approach, with an average cover of more than 70%. One of these taxa has been sequenced for the first time. These findings underline the high ecological value of this area as a hotspot of benthic biodiversity and highlight the importance of marine protected area management and regional monitoring programs to ensure the conservation of these valuable yet fragile coastal ecosystems. [ABSTRACT FROM AUTHOR]

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Mediterranean coastal systems, particularly those characterized by river mouths, have played an important role in the history of human civilization, thanks to unique species assemblages, a high biodiversity, and complex ecological interactions. The overlapping of multiple cross-scale effects, triggered by the ongoing climate change, makes these systems particularly important sites for ecological studies. Here, we have investigated the phytoplankton community structure in the terminal stretch of the Sele River (Tyrrhenian Sea) under two different hydrological regimes: i) with river mouth occluded by sediments preventing water exchange with the sea; ii) with river mouth completely opened, which allowed the maximum water mass exchanges between the river and the sea. The strong variations in physical-chemical properties of the water column, the point-distribution of total phytoplankton biomass, and the dominance of cryptophytes and cyanophytes under occluded and opened river mouth, respectively, indicate the presence of strong allogenic pressures acting on the system. Our data suggest that the monitoring of phytoplankton communities in the terminal stretch of micro-tidal estuaries, could be a useful tool for studying the extent of climate change underway in Mediterranean coastal marine areas.

Knowledge of post-larval swordfish (Xiphias gladius) ecology in the world’s oceans is incomplete as they are rarely found in ichthyoplankton samplings or commercial catches and individuals are difficult to observe in the marine ecosystem. Analyses of stomach contents of apex predators can provide otherwise unobtainable ecological insights. Two well-preserved bills of post-larval swordfish were identified among the partially digested stomach contents of an adult male dolphinfish (Coryphaena hippurus) caught in the northern Tyrrhenian Sea. The lower jaw to fork lengths of the two predated swordfish were estimated at, respectively, 18 and 22 cm, corresponding to 81- and 99-day-old swordfish hatched in the 2022 spawning season. This analysis and recent information on the reproductive dynamics of swordfish in the same area reported in the literature shed light not only on the early stages of swordfish growth but also on dolphinfish ecology in the Tyrrhenian Sea. The two species share the same habitat and are both caught with commercial pelagic surface longlines. Environmental shifts associated with climate change could unpredictably modify the reproduction dynamics, growth, recruitment and distribution of both species. This knowledge is important for the sustainable management of regional fisheries.

Simple Summary: Loggerhead sea turtles have a flexible distribution from oceanic-pelagic to neritic-benthic areas. Their dietary preferences are expected to change from pelagic prey to benthic prey along with habitat use while they increase in size. This study evaluated the gastrointestinal contents of 150 loggerhead sea turtles stranded and/or bycaught along the Italian coasts of the central Adriatic Sea and central Tyrrhenian sea to assess the most common prey phyla. Information on the ingestion of litter has been collected for each carcass as well. This work highlights the need to deepen the knowledge of the feeding ecology and distribution of sea turtles at any developmental stage. According to their life stage, the loggerhead sea turtle (Caretta caretta) is found in a wide range of habitats, from neritic to more oceanic areas. Their feeding habits are expected to change as they develop, along with habitat use. Juvenile sea turtles are hypothesized to feed on pelagic species in oceanic areas, shifting to more benthic prey during the subadult and adult stages. We analyzed the gastrointestinal content from 150 loggerhead sea turtles stranded and/or bycaught along the Adriatic coast of the Abruzzo and Molise regions (n = 89) and the Tyrrhenian coast of the Lazio and Campania regions (n = 61) from 2018 to 2021. Food items were identified to the lowest taxonomic level, and the frequency of occurrence was calculated for each taxon and most recurrent species to assess changes in prey selection during the development. The marine litter was categorized, and the frequency of occurrence was calculated for the ingestion of litter. The most recurrent taxonomic prey group recorded in the Adriatic sample was Arthropoda (94%), followed by Mollusca (63%) and Chordata (34%). In the Tyrrhenian sample, loggerhead sea turtles fed mostly on Mollusca (84%), Arthropoda (38%), and Chordata (26%). Surprisingly, the Adriatic-Tyrrhenian sample groups showed similar feeding behavior between juveniles, subadults, and adults. A similar correlation has been observed concerning the ingestion of litter. Moreover, this study confirms the opportunistic feeding behavior of loggerhead sea turtles and their high adaptability. [ABSTRACT FROM AUTHOR]

The fin whale Balaenoptera physalus is a large rorqual species occurring worldwide, mainly in temperate and subpolar zones. In contrast to many baleen whales, not all the fin whale populations show the same model of migration. In fact, migratory behaviours of this latter species range from long seasonal migration between high and low latitudes to a complete non-migratory behaviour. A resident fin whale population was described in the Mediterranean Sea, which is also frequented by North Atlantic individuals entering through the Strait of Gibraltar in winter to feed. Between 2020 and 2021 three individuals initially identified as fin whales died along the Tyrrhenian coasts (Mediterranean Sea, Italy). Their mitochondrial DNA control region (mtDNA CR) was analysed and compared to fin whale haplotypes previously described in North Atlantic Ocean and Mediterranean Sea to identify their geographical origin. Our results show that two individuals most likely belong to the Mediterranean fin whale population, while an individual was recognised as a putative fin-blue whale hybrid (Balaenoptera physalus x Balaenoptera musculus) with a North Atlantic origin. The discovery of the first fin-blue whale hybrid in the Mediterranean Sea was confirmed by the analysis of a biparentally inherited marker, the α-lactalbumin (α-lac) nuclear gene, demonstrating that the morphological analysis alone does not allow to correctly identify hybrids, especially if intermediate characters of both parental species are not clearly distinguishable. [ABSTRACT FROM AUTHOR]

Marine Animal Forests (MAFs) form three-dimensional seascapes and provide substrate and shelter for a variety of species. We investigated the fine-scale distribution pattern of three habitat-forming species of the coastal Mediterranean MAFs: Eunicella cavolini , E. singularis and Paramuricea clavata , and assessed the influence of terrain, oceanographic, and biological factors on their distribution and the formation of MAFs in the central-northern Tyrrhenian Sea. Species presence and abundance were obtained through seafloor HD imagery and were combined with terrain and oceanographic parameters extracted from remote sensing data using distance-based linear modeling (DistLM) and generalized additive model (GAM). The three studied species occurred in all the study areas, with marked differences in their abundance and distribution across the different sites and habitat type, in relation to seafloor characteristics. Specifically, positive relationships emerged between the density of colonies and terrain parameters indicative of high seafloor complexity, such as slope and roughness, as well as the number species structuring MAFs. A clear niche separation for the three species was observed: E. cavolini and P. clavata were reported on coralligenous reefs, and in areas where the seafloor complexity may enhance hydrodynamics and transport of organic matter, while E. singularis was observed on red algal mats at shallower depths. A better understanding of the ecology of these gorgonians, as well as of the drivers determining MAFs formation, represent the first step toward the conservation of these threatened habitats which are currently poorly protected by management and conservation plans. • Terrain, oceanographic, and biological parameters shape fine-scale octocoral distribution patterns. • Eunicella cavolini , E. singularis , and P. clavata exhibit different ecological requirements and habitat selection. • Eunicella cavolini is the most abundant octocoral species in central-northern Tyrrhenian coastal areas. • Seafloor slope and ruggedness increase MAFs' complexity, mainly on coralligenous reefs and emisciaphilic red algal mats. • The patterns here defined can support conservation strategies and restoration efforts. [ABSTRACT FROM AUTHOR]

The relationship between environmental conditions and early life-history traits of Sardinella aurita are investigated using material collected in two sites of the Central Mediterranean Sea. Individual mean daily growth during the planktonic phase has been determined by using otolith microstructure analysis, while Lagrangian simulation models allowed to estimate the daily position in space and time of each specimen from the hatching to the catch. Generalized Additive Mixed Models (GAMMs) have been implemented to explore the impact of environmental conditions at time t, t-1 day and t-2 days on the mean daily growth rate occurring at time t. Spatial analysis evidenced a wide dispersion of eggs and larvae in the coastal area of both sampling sites in correspondence to relatively warmer and chlorophyll-a enriched waters. Lagrangian simulations detected a complementary larval dispersal pathway able to transport larvae to a known retention area. Temperature at time t was the most important driver affecting the mean daily larval growth, followed by the food availability. On the other hand, models performed on lagged environmental covariates (t-1 and t-2) did not show any significant effect on the growth rate at time t. In addition to the sub-linear positive correlation between temperature and mean daily larval growth, model highlighted a decrease in the otolith core width at higher temperature that can be linked to an earlier stage of ontogeny at hatching. This study provided a useful methodological approach that takes advantage of available remote sensing data to perform ecological studies in support to fisheries management.

We propose a processing workflow to enhance the information content of aeromagnetic data. Our workflow is based on the downward continuation and subsequent L-transform of magnetic data. This workflow returns a map showing single highs, which correspond to the location of magnetic bodies, and does not need any a priori information about the source magnetization. We validated our workflow using the aeromagnetic anomalies of the Tyrrhenian Sea (Italy), by a comparison of the reprocessed aeromagnetic anomalies with high-resolution shipborne magnetic data in three selected areas. Through this comparison, we show that the proposed processing workflow of aeromagnetic data leads to more accurate interpretative results. Our results indicate that, in areas where higher resolution data are lacking, the reprocessing of aeromagnetic data according to our workflow may be as decisive as to suggest changes to their previous interpretations or, at least, useful for highlighting areas of special interest, deserving to be magnetically explored by a dedicated high-resolution shipborne survey. [ABSTRACT FROM AUTHOR]

Ichthyoplankton assemblages in the south central Tyrrhenian Sea are not known in spite of this being an intensely fished area. There are two large canyons in this region: Dohrn, in the Gulf of Naples, and Cuma, at the south end of the Gulf of Gaeta. In this study, we provide the first description of summer ichthyoplankton assemblages in the vicinity of the two canyons and present the physical features and Lagrangian particle tracking analyses at the time of the sampling. We identified fish larvae of 19 families and fish eggs of 8 families. The most abundant species was Engraulis encrasicolus, which was found at densities comparable to other known spawning grounds of the western Mediterranean. Mesopelagic species, such as Gonostomatidae and Myctophidae, were also abundant, especially at the Cuma Canyon. The notochord and standard length of the E. encrasicolus larvae ranged from 2.06 to 10.47 mm and was significantly smaller at the Cuma stations than at the Dohrn stations, suggesting the presence of sub‐populations with different spawning phenologies. The passive particle tracking analyses and the examination of currents confirmed distinct circulation features between the two sampled regions and in relation to depth and proximity to the canyon heads. These results uncover previously unknown rich assemblages of fish eggs and larvae and have conservation and management implications given the proximity of these canyons to a marine protected area and to an intensely fished continental shelf. [ABSTRACT FROM AUTHOR]

In recent years, the introduction of alien and invasive marine species in the Mediterranean Sea has rapidly increased. Laonome triangularis is a sabellid worm, native to the Australian coasts. Its first record in the Mediterranean Sea dates back to 2009 and, in this area, it is currently labeled as an allochthonous species. In the present work, we report the fìrst record of this polycheate in Italian waters and we provide some diagnostic features that are useful to identify the species.

Sociality and ecological drivers that can influence individual association patterns are infrequently considered in wildlife management, although they are essential aspects affecting animals’ responses to both human-related pressures and conservation strategies. In common bottlenose dolphins (Tursiops truncatus), sex-specific social dynamics and interactions with anthropogenic activities may affect grouping and induce changes in relationships between individuals. Out of a total of 347 individuals, we assessed the level of association among 68 bottlenose dolphins that have been sighted more than five times near the Roman coast (central Mediterranean Sea, Italy). The half-weight index (HWI) of dyadic associations, their network relations, and stability over time were investigated by using the SOCPROG software. Outcomes showed that females were more strongly associated than other individuals, with both preferred constant short-term associations and random long-term associations, possibly resulting in greater success in rearing young. Individuals interacting with the bottom trawl fishery showed weaker and short-term associations. Temporary disruption of individual associations during interaction with fishery and the relatively low number of females with calves participating in depredation seem to denote both the opportunistic nature of interactions with fishing vessels and the offspring-related protection strategy. The results show that the dolphins in this region maintain a complex but flexible social structure that varies with local biological requirements and is resilient to anthropogenic pressures.

Varunaivibrio sulfuroxidans type strain TC8T is a mesophilic, facultatively anaerobic, facultatively chemolithoautotrophic alphaproteobacterium isolated from a sulfidic shallow-water marine gas vent located at Tor Caldara, Tyrrhenian Sea, Italy. V. sulfuroxidans belongs to the family Thalassospiraceae within the Alphaproteobacteria, with Magnetovibrio blakemorei as its closest relative. The genome of V. sulfuroxidans encodes the genes involved in sulfur, thiosulfate and sulfide oxidation, as well as nitrate and oxygen respiration. The genome encodes the genes involved in carbon fixation via the Calvin–Benson–Bassham cycle, in addition to genes involved in glycolysis and the TCA cycle, indicating a mixotrophic lifestyle. Genes involved in the detoxification of mercury and arsenate are also present. The genome also encodes a complete flagellar complex, one intact prophage and one CRISPR, as well as a putative DNA uptake mechanism mediated by the type IVc (aka Tad pilus) secretion system. Overall, the genome of Varunaivibrio sulfuroxidans highlights the organism’s metabolic versatility, a characteristic that makes this strain well-adapted to the dynamic environmental conditions of sulfidic gas vents.

Petroleum-based microplastic particles (MPs) are carriers of antimicrobial resistance genes (ARGs) in aquatic environments, influencing the selection and spread of antimicrobial resistance. This research characterized MP and natural organic particle (NOP) bacterial communities and resistomes in the Tyrrhenian Sea, a region impacted by plastic pollution and climate change. MP and NOP bacterial communities were similar but different from the free-living planktonic communities. Likewise, MP and NOP ARG abundances were similar but different (higher) from the planktonic communities. MP and NOP metagenome-assembled genomes contained ARGs associated with mobile genetic elements and exhibited co-occurrence with metal resistance genes. Overall, these findings show that MPs and NOPs harbor potential pathogenic and antimicrobial resistant bacteria, which can aid in the spread of antimicrobial resistance. Further, petroleum-based MPs do not represent novel ecological niches for allochthonous bacteria; rather, they synergize with NOPs, collectively facilitating the spread of antimicrobial resistance in marine ecosystems. • PE and PP dominate microplastic pollution in the Tyrrhenian Sea. • Biofilm communities on microplastic and NOPs differ significantly from pelagic ones. • Biofilm bacterial communities on microplastics and NOPs show striking similarity. • MAG analysis reveals co-occurrence of ARGs and MGEs in biofilms. [ABSTRACT FROM AUTHOR]

Fucales (Phaeophyceae) are ecosystem engineers and forest-forming macroalgae whose populations are declining dramatically. In the Mediterranean Sea, Cystoseira sensu lato (s.l.)—encompassing the genera Cystoseira sensu stricto, Ericaria, and Gongolaria—is the most diverse group, and many species have been shown to be locally extinct in many areas, resulting in a shift toward structurally less complex habitats with the consequent loss of ecosystem functions and services. In this study, we report on the extensive occurrence of healthy and dense marine forests formed by Fucales in the Santa Maria di Castellabate Marine Protected Area in Cilento, Italy (Tyrrhenian Sea, Mediterranean). On a total area of 129.45 ha, 10 Cystoseira s.l. taxa were detected using a combined morphological and molecular approach, with an average cover of more than 70%. One of these taxa has been sequenced for the first time. These findings underline the high ecological value of this area as a hotspot of benthic biodiversity and highlight the importance of marine protected area management and regional monitoring programs to ensure the conservation of these valuable yet fragile coastal ecosystems.

We report the discovery of the Indo-Pacific sacoglossan Elysia nealae Ostergaard, 1955 from northeastern Sardinia (Central Tyrrhenian Sea). This is the first record of this species in the western Mediterranean Sea and only the second for the whole of the Mediterranean Sea following a report from Cape Epanomi, Greece. We discuss the identification of this species as well as the expansion of its geographical range. Data on the ecology and behavior of E. nealae leads us to hypothesize that the increase in the Mediterranean's water temperature due to climate change has favored this non-native species and contributed to its expanded distribution. [ABSTRACT FROM AUTHOR]

Numerical simulations of a range of wave climates and tide conditions made with the model XBeach are exploited to study propagation, evolution, dissipation, and reflection patterns of infragravity waves (IGW) at the intermediate‐to‐dissipative beach of Sabaudia (Tyrrhenian sea, Italy). On the basis of a novel calibration process performed using field swash properties collected by a nearby monitoring station, the model reproduces average run‐up characteristics with good skill (Willmott index of agreement of 0.61 for R2%). IGW at Sabaudia beach evolves exclusively as bound long waves growing across the shoaling region for both mild and intense wave climates. Furthermore, values of the dimensionless bed slope βH at which transition from steep‐to mild‐slope behavior occurs are higher than the threshold commonly assumed in the literature. Finally, although the small tide (0.4 m between mean high water spring and mean high water spring; tide range/breaking wave amplitude ratios between 0.14 and 1.1) does not alter bulk IGW reflection significantly, low tide is effective in reducing onshore IGW fluxes and, ultimately, reflection coefficients R2 selectively for intermediate IG frequencies. Our study, for the first time, gives clear evidence that the tide has a role in determining frequency‐dependent IGW dynamics and altering the dissipative state of a mild sloping beach also in a microtidal environment. Plain Language Summary: Infragravity waves (IGW) are long‐period oscillations of the water level, usually underlying common short waves. They are relevant to a number of coastal processes, like beach inundation and sand mobilization. A set of storm conditions and tidal levels is here simulated with a computer to observe how IGW evolves and dissipates at the beach of Sabaudia (Italy), characterized by low slopes and a small tidal excursion. It is found that IGW at Sabaudia develop and intensifies by gaining energy from short wind waves as they travel toward the shore. IGW are eventually set free to propagate where short waves start to break, and then stop growing or begin to decay due to the increasing dissipation they meet when they travel in low waters. The presence of IGW at Sabaudia is dominant, especially during intense storms. We have also seen that the variation of the tidal level at Sabaudia is capable of changing how much of the IGW energy is able to reach the shore, mainly for an intermediate range of IGW wave periods. We suggest that tide should be taken into account when evaluating beach inundation due to waves, even on coasts when the tidal range is small. Key Points: Storms and tide are simulated with XBeach through an innovative calibration approach, to study infragravity waves at Sabaudia (Italy)Bound long waves grow in the shoaling zone and stop growing/decay in the surf zone, with no shoreline dissipationAlbeit small, tidal excursion significantly alters onshore fluxes and reflection coefficients for intermediate IG frequencies [ABSTRACT FROM AUTHOR]

Featured Application: The database featured in the present work aims to support researchers and decisionmakers in planning future investigations and in evaluating current knowledge on polycyclic aromatic hydrocarbons when it comes to fixing the limits to PAH levels in fishery products. The aim of this work was to collect and harmonize the results of several studies achieved over the years, in order to obtain a database of georeferenced observations on polycyclic aromatic hydrocarbons (PAHs) in Western and Central Mediterranean seafood. For each observation, some information on the taxonomy and the ecology of the sampled species are reported, as well as details on the investigated hydrocarbon, and spatial and temporal information on sampling. Moreover, two health risk indexes were calculated for each record and included in the database. Through several statistical methods, we conducted a meta-analysis of the data on some of the species in this database, identifying trends that could be related to the biology of the investigated organisms, as well as to the physico-chemical properties of each hydrocarbon and to the oceanographic characteristic of this part of the Mediterranean. The analysis of the data showed that, at a consumption rate like the one typical of the Italian population, seafood caught from the area considered in the present work seems to pose a minimal risk to health. However, we also found evidence of an increasing trend of PAH concentrations in Mediterranean mussels, pointing to the need for constant monitoring. [ABSTRACT FROM AUTHOR]

Landscape evolution over the last 8000 years in three areas located along Tuscany, Latium, and Campania coasts (central Tyrrhenian) has been deduced through a morphological, stratigraphical, and historical approach considering the physical evolution and human activity. Between 8000 and 6000 yr BP, the Sea Level Rise (SLR) dominated and, near the river mouths, inlets occurred. In the Tuscany area, Mt. Argentario was an island and to SE of the Ansedonia promontory a lagoon occurred. The areas were covered by a dense forest and the human influence was negligible. Between 6000 and 4000 yr BP, humans organized settlements and activities, and a general coastline progradation occurred. A tombolo linked Mt. Argentario to the mainland. In the Tiber and Campania areas, coastal lakes and a strand plain developed. Between 4000 and 3000 yr BP, near Mt. Argentario, two tombolos enclosed a wide lagoon. At the SE of the Ansedonia promontory, the lagoon split into smaller water bodies. In the Tiber and Campania areas, delta cusps developed. The anthropogenic presence was widespread and forests decreased. During the last 3000 years, anthropic forcing increased when the Etruscans and Romans changed the territory through towns, salt pans, and ports. After the Roman period, natural forcing returned to dominate until the birth of the Italian State and technological evolution. [ABSTRACT FROM AUTHOR]

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Abstract Sabellaria alveolata (Linnaeus 1767) is a polychaete able to build bioconstructions of different thickness, size and patchiness, in intertidal and subtidal environments. Its biological features have been the object of numerous studies worldwide. The worm reefs are formed by millions of tubes built by sand and shells (whole or in fragments) bonded together with a strong glue produced by the worm itself. Hence, Sabellaria alveolata represents a sedimentological asset for the coastal protection, since it contributes to create natural barriers against storm waves and erosion, and supplies the beach with new sandy deposits. This work shows a multidisciplinary approach to studying a bioconstruction of Sabellaria alveolata along the Latium coast (Ostia, Tyrrhenian Sea, central Italy), proposing image analysis as a novel technique to investigate worm reefs, along with classical sedimentological/ecological tools. The Sabellaria bioconstructions have been analysed at different scales of observation, suggesting the more appropriate strategies to develop a reliable model illustrating the different growth steps of these bioconstructions.

According to their life stage, the loggerhead sea turtle (Caretta caretta) is found in a wide range of habitats, from neritic to more oceanic areas. Their feeding habits are expected to change as they develop, along with habitat use. Juvenile sea turtles are hypothesized to feed on pelagic species in oceanic areas, shifting to more benthic prey during the subadult and adult stages. We analyzed the gastrointestinal content from 150 loggerhead sea turtles stranded and/or bycaught along the Adriatic coast of the Abruzzo and Molise regions (n = 89) and the Tyrrhenian coast of the Lazio and Campania regions (n = 61) from 2018 to 2021. Food items were identified to the lowest taxonomic level, and the frequency of occurrence was calculated for each taxon and most recurrent species to assess changes in prey selection during the development. The marine litter was categorized, and the frequency of occurrence was calculated for the ingestion of litter. The most recurrent taxonomic prey group recorded in the Adriatic sample was Arthropoda (94%), followed by Mollusca (63%) and Chordata (34%). In the Tyrrhenian sample, loggerhead sea turtles fed mostly on Mollusca (84%), Arthropoda (38%), and Chordata (26%). Surprisingly, the Adriatic-Tyrrhenian sample groups showed similar feeding behavior between juveniles, subadults, and adults. A similar correlation has been observed concerning the ingestion of litter. Moreover, this study confirms the opportunistic feeding behavior of loggerhead sea turtles and their high adaptability.

In this study, gamete release by Caulerpa cylindracea was investigated for the first time in the Tyrrhenian Sea (Sardinia, Western Mediterranean), focusing on the main environmental factors triggering gametogenesis and spawning of the species. For this purpose, a combination of field and laboratory experiments was conducted. First, a 2-year mensurative experiment was performed in the field during summer to individuate and quantify the occurrence of C. cylindracea gametogenesis and spawning events, linking them to environmental conditions. Then, based on the results of the field work, a laboratory experiment was performed to directly test, under controlled conditions, the effect on the above-mentioned processes of two abiotic factors that appeared to play a key role in species gamete release processes in the area: sea water temperature and water movement. During the 2 years of field research, several gametogenesis events were recorded in the study area and two spawning events also occurred. Significant differences were observed between the ratio of fertile and total thalli and between releasing thalli (RT) and fertile thalli (FT), among sites with different hydrodynamic conditions and sampling periods with different sea water temperatures. Overall, these results suggest that C. cylindracea sexual reproduction also occurs in the Tyrrhenian Sea, and that, therefore, new genotypes that favor the invasive profile of the species could be produced in the basin, where both its gametogenesis and spawning seem to be mainly regulated by water movement and sea water temperature.

Thermohaline staircases are a well-known peculiar feature of the Tyrrhenian Sea. Generated by extensive double diffusion processes fueled by lateral intrusions, they are considered to be the most stable of all the staircases that have been detected in the world ocean, seeing their persistence of more than 40 years in the literature. Double diffusion leads to efficient vertical mixing, potentially playing a significant role in guiding the diapycnal mixing. The present study investigates this process of mixing in the case of the Tyrrhenian staircases by calculating the heat and salt fluxes in their gradient zones (interfaces) and the resulting net fluxes in adjacent layers using hydrological profiles collected from 2003 to 2016 at a station in the heart of the basin interior. The staircases favor downward fluxes of heat and salt, and the results of the calculations show that these are greater where temperature and salinity gradients are also high. This condition is more frequently encountered at thin and sharp interfaces, which sometimes appear as substructures of the thicker interfaces of the staircases. These substructures are hot spots where vertical fluxes are further accentuated. Due to the increasing salt and heat content of the Levantine Intermediate Water (LIW) during the observation period, a rise in the values of the fluxes was noted in the portion of the water column below it down to about 1800 m. The data furthermore show that internal gravity waves can modulate the structure of the staircases and very likely contribute to the mixing, too, but the sampling frequency of the time series is too large to permit a proper assessment of these processes. It is shown that, at least during the period of observation, the fluxes due to salt fingers do not reach the bottom layer but remain within the staircases.