1,721,002 research outputs found
Baseline on rare earth elements in the marine sediments of a Mediterranean commercial port as environmental tracers and their relationships with inorganic contaminants
No full textThe Port of Genoa (north-western Mediterranean Sea) receives sediments from two different catchment areas
(Bisagno and Polcevera torrents). The aim of the work is to evaluate if Rare Earth Elements (REEs) could be used to identify the two sedimentary inputs and to unravel the origin of inorganic contaminants in an anthropised basin. REE results constitute a baseline for this port. The main REE-bearing minerals are phosphates and zircon. As, Cd, Hg, Pb, and Sn concentrate in the sediments closer to the Bisagno Torrent mouth, and the correlation with Ca and Light-REEs suggests their plausible geological origin. Co, Mn, and Ni maxima lie in the sediments closer to the Polcevera Torrent. Their correlation with Middle-REEs and Mg suggest that ophiolitic rocks could explain their presence. Cr, Cu, V, and Zn do not show a clear correlation with REEs, and their origin probably is a combination of natural and anthropogenic sources
Use of microseismic data to monitor significant sea wave heights in support of marine weather forecasting and coastal protection
No full textThe focus of the Ph.D. project was the implementation of a network for monitoring significant sea wave heights (Hs) along the Ligurian coasts (north-western Mediterranean Sea), in order to provide near-real time data to weather forecasters and sea users (vessel captains, pilots, Coast Guard, Port Authorities and yachtsmen). The project was divided into a part dedicated to the use of microseismic data, interfaced with data derived from modelling hindcasts and from the wave buoy of Capo Mele, for the determination of Hs, and a part dedicated to the Interreg Italy-France Maritime 2014-2020 SINAPSI "Assistance to navigation for safe access to ports” Project, which involves the installation of instruments for measuring weather and sea parameters along the coasts of the Ligurian Sea.
The first phase of the Ph.D. project involved the study and updating of a mathematical procedure for the estimation of Hs from the microseismic data recorded by the network of seismic stations along the Ligurian arch. The procedure exploited the existing relationship between sea wave heights and microseismic signal and included the use of hindcast data to calibration steps and data from the Capo Mele wave buoy to verify the reliability of the estimated Hs data. In October 2018, an extreme sea storm hit the Ligurian coast with waves characterised by Hs greater than 6 m; these wave heights were not matched by an equivalent energy in the microseismic signal, which therefore led to an underestimation of the Hs estimated by the procedure. It was therefore necessary to investigate the extreme event of 2018, which led to the evidence of a lack in the energy of the microseismic signal and the need for a data compensation, which was possible thanks to the use of weather data (wind speed and atmospheric pressure) that were included in an additional element to the estimation procedure. The second phase of the Ph.D. project therefore involved verifying the reliability of the data estimated by the procedure, which led to the evidence of a generic underestimation of Hs. This led to the study of a first modification of the procedure and to the consequent monitoring of its validity on a large time scale. The monitoring of the reliability of the estimated data will be continued after the end of the Ph.D., as well as the updating/refinement of the procedure.
The Ph.D. project involved the participation in the SINAPSI Project, which started in April 2019, in all its components, from the management to the implementation of the monitoring network, also including the communication and dissemination of the project activities to the stakeholders.
The Ph.D. has achieved the improvement of the Hs estimation procedure. The research activities will continue beyond the Ph.D. natural end to implement the results with data from a radar antenna system that will be installed in the Genoa area in the framework of the SINAPSI Project
Changes in the physical characteristics of the water column at the mouth of a torrent during an extreme rainfall event
No full textThe city of Genoa (Italy) was hit by a severe flash flood on the 4th November, 2011. The effects of this event on the water column at the mouth of the Polcevera Torrent, the main water course flowing into the Port of Genoa, are presented in this paper. The hydrological characteristics were measured with two conductivity–temperature–depth probes equipped with a turbidimeter, one fixed on the port breakwater and one used at mobile stations around the mouth of the torrent. The dynamics were measured with a horizontal acoustic Doppler current profiler (H-ADCP) fixed on the breakwater. Data collected before, during and after the flash flood were analysed to quantify the changes due to the event. The weather conditions during the event showed extremely heavy rain associated with strong weather instability, the convergence of a low-level southerly flow and the persistence of a squall line over a restricted area. The temperature, salinity, turbidity and dissolved oxygen measurements taken during the event showed the strong influence of the weather conditions and the fresh water input of the torrent itself on the water column at its mouth, an influence that dissipated during the following days. Instead, the dynamics measured at the mouth of the torrent were affected more by the strong south-easterly wind and the sea than the flow of fresh water
Applicability of an empirical law to predict significant sea-wave heights from microseisms along the Western Ligurian Coast (Italy)
No full textThe use of microseisms with appropriate predictive laws is a reliable method for estimating such seawave parameters as period and significant height. Through the use of opportune predictive laws calibrated with measurements obtained from wave buoys, it is possible to determine the significant height of
the wave as a function of the spectral energy-content of the microseism. In this paper we will present a
procedure that utilises microseisms recorded by a micro network of five seismic stations to predict the
significant height of waves, and its uncertainty, along the western Ligurian coast (Italy). The calibration
and validation of the procedure was performed using wave measurements obtained from a wave buoy off
Capo Mele (Imperia, Italy) over a two and a half year period. The differences between the significant
heights measured by the wave buoy and the empirical predictions were less than 10 cm (corresponding
to 10% of the mean measured value) for 47% of the data and less than 20 cm (corresponding to 20% of the
mean measured value) for 72%
Identification of the different sources of contaminants in the metal impacted Gromolo Torrent and related marine sediments
No full textEnvironmental implications of metal mobility in marine sediments receiving input from a torrent affected by mine discharge
No full textAcid Mine Drainage (AMD) is one of the most important sources of pollution in fluvial systems and can enrich rivers in dissolved and suspended metals of environmental concern. Colloidal particles may favour the transport of metals to the sea, where metals can be accumulated in bottom sediments. The aim of this paper was to evaluate the mobility of metals in the “Baia delle Favole” bottom sediments (Sestri Levante, Italy), which receive the input of the AMD impacted Gromolo Torrent, using chemical speciation (BCR sequential extraction). Basing on the Risk Assessment Code (RAC), our results showed a systematic and widespread high risk classification for Mn, whereas a medium risk is associated to Co, Cu, and Zn in the sediments collected near the mouth of the Gromolo Torrent. Moreover, in these sediments the occurrence of Fe oxyhydroxides has been observed, reflecting an increase of metals in the reducible fraction obtained with BCR
PTE (Potential ecotoxic Element) mobility in stream and marine sediments: the case of Gromolo Torrent (eastern Liguria, Italy.
No full textMicroplastic characterisation in fluvial and marine sediments: the case of the Gulf of Tigullio (north-western Italy).
No full textTHE NEPHELOID BOTTOM LAYER AND THE DYNAMICS OF THE WATER MASSES AT THE SHELF-BREAK OF THE WESTERN ROSS SEA
No full textIn the austral summers of 2000/2001 and 2002/2003 the Italian CLIMA Project carried out two oceanographic cruises along the northwestern margin of the Ross Sea, where the Antarctic Bottom Water forms. Here there is an interaction between the water masses on the sea floor of the outer shelf and slope with a consequent evolution of benthic nepheloid layers and an increase in total particulate matter. We observed three different situations:(a)the presence of triads (bottom structures characterized by a concomitant jump in turbidity, temperature, and salinity data) and high re- suspension phenomena related to the presence of the Circumpolar Deep Water and its mixing with cold, salty shelf waters associated with gravity currents;(b)the absence of triads with highre-suspension, implying that when the gravity currents are no longer active the benthic nepheloid layer may persist until the suspended particles settle to the seafloor, suggesting that the turbidity data can be used to study recent gravity current events;and(c) the absence of turbidity and sediment e-suspension phenomena supports the theory that as teady situation had been re-established and the current interaction no longer occurred or had finished some time before
Environmental pollution in river and marine sediments: the case of Gromolo Torrent (Liguria, Italy)
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