North Tyrrhenian Research Articles

Formal analyses are fundamental for the definition of honey, a product representing specific territories and their changes: the case of North Tyrrhenian dunes (Italy)

Honey is a variegate matrix depending significantly on the floral origin, and it could become an important agri-food product to valorise specific territories. Being so diverse, different analytical techniques are necessary for its description. Herein we characterized the honey produced in one of the Italian sand dunes systems hosting beekeeping activities. In terms of floristic origin, phytochemical characterization, and sensory and colour analysis, honey collected in 2021 and 2022 was comparable. Honey was polyfloral, with several pollens from dune habitat plants classified as minor. The presence of the allochthonous Amorpha fruticosa L. and the ruderal Rubus fruticosus L. pollens in the category of the secondary pollens testifies the alteration of the park vegetation. The phytochemical profile was rich in polyphenols. Other interesting compounds were coumarine derivatives, likely attributable to resin-laden plants as rockroses, long chain hydroxyacids typical of royal jelly and nicotinic acid and its analogues (2-hydroxynicotinic acid and 2-hydroxyquinoline). The above-mentioned honey showed interesting features and was a good representation of the vegetation of this area. Our study pointed out the importance of relying on multiple analytical techniques for the characterization of honey and the advisability of a technical support toward beekeepers to correctly describe and valorise their product.

Unexpected Records of Newborn and Young Sharks in Ligurian and North Tyrrhenian Seas (North-Western Mediterranean Basin)

Between 2007 and 2022, 112 specimens of newborn and young pelagic sharks were recorded in the waters of Tuscany Region, in the South Ligurian–North Tyrrhenian Seas (north-western Mediterranean basin). The sharks belonged to the Carcharhinus plumbeus (n = 14), Prionace glauca (n = 66), Isurus oxyrinchus (n = 16), Mobula mobular (n = 5) Alopias vulpinus (n = 7) and Hexanchus griseus (n = 4) species. Each animal was correctly identified thanks to the photographs or videos collected. All specimens were incidentally captured with set nets in inshore shallow waters, except bluntnose six-gill sharks, which were bycatch of deep-water bottom-trawl fishery. Body mass, sex, total length and biometric measurements were recorded in 34 baby sharks following the Mediterranean Large Elasmobranches Monitoring (MEDLEM) protocol. The presence of very evident and often non-healed umbilical scar confirmed that some of the sample specimens were newborn. Further confirmation came from the comparison between the total length observed and the size at birth known for the sampled species as reported in the literature. Some baby sharks were preserved in the Museums of Natural History of Pisa and Florence University collections. The importance of the coastal area studied as a possible shark nursery is discussed.

Growth variability in Atlantic horse mackerel Trachurus trachurus (Linneus, 1758) across the central Mediterranean Sea: contrasting latitudinal gradient and different ecosystems

Data on Atlantic horse mackerel Trachurus trachurus (Linneus, 1758) were collected along 8-year acoustic surveys (2011-2018). Age and growth variability of horse mackerel from the Central Mediterranean Sea were investigated within different, contrasting habitats, from the south of Sicily to the north Tyrrhenian (Ligurian Sea). Data from satellite provided the habitat features along the study period over the whole surveyed area. For comparison purposes, according to the ecosystems difference the study area has been split into four subareas: Strait of Sicily (SoS), North of Sicily (NS), south Tyrrhenian Sea (ST) and north Tyrrhenian Sea (NT). In terms of the FAO Geographical Sub-Area definition the SoS corresponding to GSA15 and 16, NS to GSA 10 south, ST to GSA10 north and NT to GSA 9. Results showed a growth homogeneity in the study area, suggesting a unique stock inhabiting these waters. The only exception was recorded for juveniles (Age 0 class) in the SoS, where a lower size at age was detected compared to other areas. A multiple linear modelling analyses suggested that variability in length at age 0 was mainly linked to the oceanographic differences between an upwelling driven system (Strait of Sicily) and the other ecosystems, where enrichment processes are mainly due to river runoff (relevant in ST and NT). Namely, Absolute Dynamic Topography (ADT) and body condition factor (Kn) were significantly related to differences in length at age 0. Results revealed that currents (and gyres) are among the principal abiotic factors controlling Atlantic horse mackerel growth in its first year of life, suggesting that circulation and food-related processes (i.e., zooplankton concentration) are of major importance for this species. Finally preliminary observations suggest the Strait of Sicily may be the main spawning area among those analyzed.

Application of machine learning techniques to derive sea water turbidity from Sentinel-2 imagery

Earth Observation (EO) from satellites has the potential to provide comprehensive, rapid and inexpensive information about water bodies, integrating in situ measurements. Traditional methods to retrieve optically active water quality parameters from satellite data are based on semi-empirical models relying on few bands, which often revealed to be site and season specific. The use of machine learning (ML) for remotely sensed water quality estimation has spread in recent years thanks to the advances in algorithm development and computing power. These models allow to exploit the wealth of spectral information through more flexible relationships and are less affected by atmospheric and other background factors. The present study explores the use of Sentinel-2 MultiSpectral Instrument (MSI) Level-1C Top of Atmosphere spectral radiance to derive water turbidity, through application of machine learning techniques. A dataset of 222 combination of turbidity measurements, collected in the North Tyrrhenian Sea – Italy from 2015 to 2021, and values of the 13 spectral bands in the pixel corresponding to the sample location was used. Two regression techniques were tested and compared: a Stepwise Linear Regression (SLR) and a Polynomial Kernel Regression. The two models show accurate and similar performance (R2 = 0.736, RMSE = 2.03 NTU, MAE = 1.39 NTU for the SLR and R2 = 0.725, RMSE = 2.07 NTU, MAE = 1.40 NTU for the Kernel). A band importance analysis revealed the contribution of the different spectral bands and the main role of the red-edge range. The work shows that it is possible to reach a good accuracy in turbidity estimation from MSI TOA reflectance using ML models, fed by the whole spectrum of available bands, although the possible generation of errors related to atmospheric effect in turbidity estimates was not evaluated. Comparison between turbidity estimates obtained from the models with turbidity data from Copernicus CMEMS dataset named ‘Mediterranean Sea, Bio-Geo-Chemical, L3, daily observation’ produced consistent results. Finally, turbidity maps from satellite imagery were produced for the study area, showing the ability of the models to catch extreme events.

Microplastics in seawater and marine organisms: Site-specific variations over two-year study in Giglio Island (North Tyrrhenian Sea)

Geographical and temporal differences of microplastic occurrence were documented in water and fish collected in 2017 and 2019 from the Giglio Island (North Tyrrhenian Sea) close to the area where the Costa Concordia sank in January 2012. Results on water samples showed a site-dependent difference, suggesting the role of surface current dynamics in the microplastic local distribution, while tested Neuston nets (200 μm and 330 μm mesh size) did not influence microplastic retention efficiency. Fish exhibited in 2019 a higher frequency of specimens positive to microplastic ingestion with respect to 2017, with an occurrence higher than those typically observed in other Mediterranean areas. Both in water and fish, fragments were the dominating shape, polypropylene and polyethylene were the prevalent polymers, without particular difference between sites and years. This study highlights the importance of applying microplastic investigation in biotic and abiotic matrices for an effective monitoring of this pollution in the marine environment.

Contatti linguistici lungo le coste tirreniche: storia della parola marruffo

Abstract The article intends to reconstruct the linguistic history of a particular fishing gear called marruffo, which is still used in the Gulf of Naples and in a few places of the North Tyrrhenian coasts. The marruffo is a fishing trap used by fishermen to preserve the catch while awaiting sale. Conical in shape, it looks like a large basket with a lid, in which fish or crustaceans of various types are placed. Starting from the 1871 work by the naturalist Achille Costa, entitled La pesca nel golfo di Napoli, the attestations of marruffo in Campania, Sardinia and Corsica are outlined. I put forward the hypothesis that the object arrived on the Tyrrhenian coasts as a consequence of migrations of fishermen from the Neapolitan area to the islands of Tuscany, Sardinia and Corsica between the 18th and 19th century. Since in southern Italy the name marruffo also indicates a jug for wine or water, I hypothesize that the word was extended from the lexicon of everyday life to the fishing lexicon throughout a process of resemantization, as it was demonstrated for other similar cases.

Chemical composition of microplastics floating on the surface of the Mediterranean Sea

The Mediterranean Sea is one of the most studied regions in the world in terms of microplastic (MP) contamination. However, only a few studies have analysed the chemical composition of MPs at the Mediterranean Sea surface. In this context, this study aims to describe the chemical composition as a function of particle size, mass and number concentrations of MPs collected in the surface waters of the Mediterranean Sea. The chemical composition showed a certain homogeneity at the Mediterranean Sea scale. The main polymers identified by Fourier Transform Infra-Red (FTIR) spectroscopy were poly(ethylene) (67.3 ± 2.4%), poly(propylene) (20.8 ± 2.1%) and poly(styrene) (3.0 ± 0.9%). Nevertheless, discrepancies, confirmed by the literature, were observed at a mesoscale level. Thus, in the North Tyrrhenian Sea, the proportion of poly(ethylene) was significantly lower than the average value of the Mediterranean Sea (57.9 ± 10.5%). Anthropic sources, rivers, or polymer ageing are assumed to be responsible for the variations observed.

The Role of Subduction Interface and Upper Plate Strength on Back‐Arc Extension: Application to Mediterranean Back‐Arc Basins

AbstractWhile there has been a lot of work focusing on improving our understanding of divergent and convergent plate boundaries, the intricate nature of back‐arc extension, where subduction and large‐scale extension occur and interact in close, is yet to be explored properly. It has long been proposed that the strength of the subduction interface, which depends among others on the amount of subducted sediments, plays a pivotal role in subduction dynamics. Here, we investigate the role of back‐arc rheology and subduction interface strength on the deformation style of the overriding plate. Using two‐dimensional thermomechanical model experiments, we demonstrate, that the presence of a weak mantle–lithospheric domain in the overriding plate can result in back‐arc breakup even during the subduction of narrow, land‐locked oceanic basins such as those found in the Mediterranean region. The thinning of the back‐arc mantle–lithosphere results in a weaker overriding plate, hence a lower slab‐pull force is sufficient to initiate back‐arc extension. Convective thinning at the subduction interface also reduces the length of the interface, reducing the portion of slab‐pull lost as energy dissipation. A weak plate interface, can also reduce the energy dissipated along the subduction zone, leading to earlier extension. A detailed analysis of the forces shaping the overriding plate stress field shows that transmission of slab‐pull force has a predominant role while viscous basal drag has a negligible effect in our experiments. Our results compare favorably with large‐scale characteristics of land‐locked Mediterranean back‐arc basins such as the North Tyrrhenian basin and the Pannonian basin.

On the selection of time-varying scenarios of wind and ocean waves: Methodologies and applications in the North Tyrrhenian Sea

This paper analyses a methodology to identify sub-series of waves parameters and wind speed able to explain the overall variability of the input dataset. To this end, the K-means clustering technique is applied to a 40-year long time series of hindcast data off the Genoa coastline (NW Italy). K-means aims to group the data in a reduced number of clusters, represented by as many modes of variability (or “model scenarios”). This work reviews and discusses a methodology to select time-varying model scenarios and assess the performances of K-means according to two indexes and increasing number of clusters. These indexes are used to compute the number of clusters best suited for the application at hand, testing different conditions as concerns the variables involved in the analysis and their temporal resolution. Results show that the indexes may not be consistent with each other, and that the number of scenarios to be reasonably employed strongly depends on how data are initially assembled. Finally, some of the model scenarios selected in front of Genoa are analysed and discussed in the framework of the local wind-wave climatology.

Characterization and biogeographic affinity of megazoobenthos in the Central Mediterranean Sea

AbstractThe Strait of Sicily (SoS) is a key area in the Central Mediterranean Sea characterized by high biodiversity and demersal fisheries productivity. Further, it is traditionally considered the main biogeographic boundary between the Western and Eastern basins of the Mediterranean. Due to the poor knowledge on the benthos composition and distribution in this area, we created the first inventory of megazoobenthos recorded on the trawlable soft bottoms of the North‐Western SoS. Samples were collected by bottom trawl surveys between 2003 and 2013 within a depth range of 10–800 m. Overall, 374 taxa with 358 species, belonging to Porifera, Cnidaria, Nemertea, Rotifera, Brachiopoda, Bryozoa, Sipuncula, Annelida, Mollusca, Arthropoda, Echinodermata and Chordata phyla, were found. In addition, the biogeographic affinity of megazoobenthos collected in the SoS to species vulnerable to trawl survey found in other zones of the Central Mediterranean was investigated. Excluding the North Adriatic and the Strait of Messina, moderate affinity values have been recorded within all the biogeographic zones. The benthos species of the North‐Western SoS presented the highest affinity with those of the North Tyrrhenian and Ligurian Sea (about 90% of species in common). However, our results show high similarity with species composition of the South‐Eastern SoS/South Ionian, North Ionian and Central Adriatic (about 80% of species in common). Our study confirms the role as biogeographic transition zone of the SoS for the Mediterranean biota. Furthermore, the lower affinity with native species of the South‐Eastern SoS and the absence of Lessepsian species suggest that the cold waters (due to the permanent up‐welling) off the southern coasts of Sicily may act as thermal barrier for regulating species exchange between the Eastern and Western basins. Some concerns about this role of the northern sector of the SoS were discussed in the light of current climate change.

Port Noise and Complaints in the North Tyrrhenian Sea and Framework for Remediation

Compared to the other relevant noise sources such as railways, roads, and airplanes, the regulation regarding port noise is lagging behind. The absence of specific laws is likely one of the main causes of the increasingly high number of complaints reported by the citizens living nearby the ports. At the same time, scientific literature concerning the impact of port noise and its mitigation is not so widespread and only a few studies are available at the moment. However, the volume of maritime traffic has increased in the last years and consequently, Port Authorities are required to assess the impact of port operations on the city soundscape without using specific directives or guidelines. In this context, the INTERREG Maritime programme projects RUMBLE, MON ACUMEN, and REPORT aim to fill this gap, by investigating the state-of-the-art of port noise in the north Tyrrhenian sea and developing helpful instruments. Data were collected via a survey sent to the Port Authorities, local environmental protection agencies and universities involved in the projects. The survey was focused on monitoring systems, previous measurement campaigns, noise maps, and citizens’ complaints already taken. The results confirmed both a lack of awareness among residents and authorities and the absence of actions aimed at reducing port noise. In this framework, the difficulties encountered by the Port Authorities in managing the ports sustainably are highlighted. An underestimation of citizens’ exposure to noise in port areas could be expected.

Measurement and Forecasting of Port Tide Hydrostatic Component in North Tyrrhenian Sea (Italy)

Starting from the end of the 90s not perodic and unpredictable variations in the depth of harbor waters were observed. Long period (from 24 hours to a few days) and wide amplitude are their main features. Experience showed that this phenomenon is a risk for harbor navigation and mooring. It may be a serious obstacle to waterside port activities. The first observation of the data does not link the super-highs and the super-dry tides to the meteorological dynamic of sea-atmosphere interaction (i.e. Storm Effect). More, the attempt to compensate for these sea depth fluctuations by means of the well-known offshore hydrobarometric inverse parameter (1 [cm] sea level variation for &#451 [hPa] atmospheric pressure variation) underestimates the amplitude of the phenomenon. In the first years of 2000, the Italian Ministry of Transport launched a national project for the definition of thee-amplitude and time of these tidal anomalous waves. The measure of harbors hydrobarometric inverse factors showed a much more intense value than the theoretical one (computed for the offshore). These amplification factors are characteristic of each harbor and can be double (in exceptional cases even more) than offshore. The delay between the arrival times of these tidal waves (induced phenomenon) respect to the time of arrival of the atmospheric pressure variation (inducing phenomenon) depends on 1) morphology of the port basin sea floor and 2) harbor and off-shre water dynamics relationship (first approximation). For these reasons the hydro barometric inverse parameter is not effectiveness computable but it can be determined statistically.

Levels of chemicals in two fish species from four Italian fishing areas

This paper reports the results of an assessment of contamination by polychlorinated biphenyls and polycyclic aromatic hydrocarbons in two demersal species of commercial importance. The organisms considered were Mullus barbatus and Engraulis encrasicolus from three marine areas off the Italian coasts: North and South Adriatic Sea and North Tyrrhenian Sea. The instrumental analyzes have revealed, in many samples examined, the presence of most of PCB congeners and 5 of the 16 PAHs considered. Organisms caught in the waters of Apulia have greater contamination values, while the samples from Tuscany showed the lowest ones, results probably referable to the environmental quality differences between the areas of origin, at least for PAHs, since the sampling areas are represented respectively by areas with presence of oil extraction plant (Adriatic), and by an area subject to environmental protection.

Assessing the Underwater Ship Noise Levels in the North Tyrrhenian Sea.

The purpose of this research was to assess the anthropic underwater noise caused by ships within the Cetacean Sanctuary, a wide area in the North Tyrrhenian Sea. Noise from low-frequency continuous sounds has been investigated within the 1/3-octave bands centered at 63 and 125 Hz. All the information about noise sources and sound attenuation have been organized in a database; a tool automatically extracts useful information from it and feeds a ray-tracing model to estimate noise levels. The results show average levels generally over the 100 dB re 1 μPa value.

Analysis of Chlorophyll-aand Primary Production Dynamics in North Tyrrhenian and Ligurian Coastal–Neritic and Oceanic Waters

ABSTRACT Marchese, C.; Lazzara, L.; Pieri, M.; Massi, L.; Nuccio, C.; Santini, C., and Maselli, F., 2015. Analysis of chlorophyll-a and primary production dynamics in north Tyrrhenian and Ligurian coastal–neritic and ocean waters. Properly tuned algorithms based on optical remote sensing data can provide estimates of chlorophyll-a (as a proxy for phytoplankton biomass) concentration in near real time, allowing the monitoring of phytoplankton dynamics for both neritic and oceanic areas. The main objective of this study was, through the use of ocean color satellite images, to offer a description of the interannual variability of chlorophyll-a and primary production both in coastal–neritic and in oceanic areas of the North Tyrrhenian and Ligurian Seas (NW Mediterranean). The second objective was to highlight the possible influence of land runoff on phytoplankton biomass variability in coastal–neritic waters. The results indicate that seasonal cycles of phytoplankton biomass and production were quite differen...

Assessment of three algorithms for the operational estimation of [CHL] from MODIS data in the Western Mediterranean Sea

Three algorithms based on MODIS imagery were evaluated for the estimation of Chlorophyll-a concentration ([CHL]) in the Western Mediterranean Sea. The first algorithm (OC3M) is usually applied at global scale, while the second (MedOC3), has been used in the Mediterranean basin. The third algorithm (SAM_LT), specifically developed for the Ligurian and North Tyrrhenian Seas, is here described and applied, in its updated version. The three algorithms were assessed through comparison with 240 sea [CHL] samples collected during the 2002–2011 decade. The results obtained show that OC3M is the most accurate algorithm when used for the entire Western Mediterranean, but is outperformed by SAM_LT in the area where this was originally developed. The impact of different MODIS quality flags on the three algorithms has been finally evaluated, providing guidelines for their operational application in the study area.

SUB-MESOSCALE WAVE HEIGHT RETURN LEVELS ON THE BASIS OF HINDCAST DATA: THE NORTH TYRRHENIAN SEA

A 32-years wave re-analysis has been employed in order to develop an extreme value analysis for the whole Ligurian Sea (North Tyrrhenian Sea). Wave hindcast data have been obtained through numerical modelling implemented at DICCA, University of Genoa, covering the whole Mediterranean Sea. Model outputs for wave characteristics (wave height, period and direction of propagation) have been extracted on 30 virtual buoys displaced in the area covering the whole temporal domain (32-years) at hourly frequency in order to develop an exhaustive wave climate analysis. A non stationary model is presented and applied in wave climate assessment with the purpose of taking account for the effects of seasonality in providing return level estimates. Time-varying model employed proved to be versatile in modelling different wave fields largely diversified in such kind of area and wave hincast data apply well in order to perform waves statistical downscaling.

The effect of breakwaters on the structure of marine soft-bottom assemblages: A case study from a North-Western Mediterranean basin

This two-year study is the first attempt to analyse the ecological effects of breakwater systems on soft-bottom assemblages along the North Tyrrhenian coast. Differently from previous studies focusing on infauna of on-shore and off-shore sides, we compared the assemblages inhabiting the surrounding soft-bottoms not directly protected by the breakwaters, defining our sampling stations at varying distances from the breakwaters and at constant distance from the coast.Data collected revealed that abundance, species richness and M-AMBI ecological quality differed between northern and southern sides, and were related to distance from structures. Multivariate analyses of relationships between assemblages and abiotic characteristics support this hypothesis. The extension of these effects, that resulted to be weak and limited to a restricted area, could be a consequence of coastal current on local hydrodynamics. This study provides novel and critical information for the management of the coastal defence infrastructure spreading along the western coast of Italy.

Typhoon at CommsNet 2013: experimental experience on AUV navigation and localization

The CommsNet 2013 experiment took place in September 2013 in the La Spezia Gulf, North Tyrrhenian Sea. Organized and scientifically led by the NATO S&T Org. Ctr. for Maritime Research and Experimentation (CMRE, formerly NURC), with the participation of several research institutions, the experiment included among its objectives the evaluation of on-board acoustic Ultra-Short Base Line (USBL) systems for navigation and localization of Autonomous Underwater Vehicles (AUVs). The ISME groups of the Universities of Florence and Pisa jointly participated to the experiment with one Typhoon class vehicle. This is a 300 m depth rated AUV with acoustic communication capabilities originally developed by the two groups for archaeological search. The CommsNet 2013 Typhoon, equipped with an acoustic modem/USBL head, navigated within the fixed nodes acoustic network deployed by CMRE. This allows the comparison between inertial navigation, acoustic self-localization and ground truth represented by GPS signals (when the vehicle was at the surface). The preliminary results of the experiment show that the acoustic USBL self-localization is effective, and it has the potential to improve the overall vehicle navigation capabilities.

Parapenaeus longirostris (Lucas, 1846) an early warning indicator species of global warming in the central Mediterranean Sea

The effect of temperature increase on the stock of the deep-sea pink shrimp (Parapenaeus longirostris) was analysed along the western coasts of Italy (North Tyrrhenian–Ligurian Sea: Geographical Sub-Area 9). This crustacean is currently one of the most important commercial species of the trawl fisheries in the Mediterranean Sea. Landings of the species in the North Tyrrhenian–Ligurian Sea have grown consistently during the last years following a rapid increase in the stock size. Since the deep-sea pink shrimp stock is exploited on the same fishing ground of other heavily overexploited stocks in a full mixed and poorly selective fishery, its condition seems to be largely independent of the current fishing exploitation pattern suggesting a positive role of climate change on the dynamic of the stock.To test this hypothesis we investigated the effect of sea surface temperature (SST) on density and distribution of P. longirostris by means of general additive models (GAMs). Two different models were developed for the whole stock and for the recruits (CL<20mm) using time series of MEDITS (International bottom trawl survey in the Mediterranean) survey density indices (n km−2) covering the period 1995–2010. Predictors included were geographical coordinates, quarterly averaged minimum SST, sampling depth and year. Spawners density was included as predictor into the GAM for recruits.The best GAM for the whole stock explained 67.1% of the total deviance, showing a clear increase in density in concomitance with the expansion of the stock northward. We found a significant positive effect of the min SST of all seasons, as expected considering that P. longirostris spawn all year round, with the highest influence played by summer min SST, either in the same or previous year.The best model for recruits explained 64.9% of the total deviance. Recruitment increased linearly with the density of spawners showing a positive temporal trend and an expansion northward. The observed trend in recruitment appeared significantly linked to minimum SST in summer and during the autumn of the previous year, with a positive effect on shrimp density over 23.5°C and 14°C respectively. The climate-related changes in recruitment appeared to be the key process driving the dynamics of the stock, involving either higher production or survival in the planktonic stages, or owing to changes in the quality/quantity of nursery habitats.