Search Results (35)

Renewable energy production is one of the pillars of the decarbonization process for the electricity system. The use of hydrogen can also contribute to the decarbonisation of industrial sectors such as chemicals, steel production, heavy industry, and long-distance transports. In Italy, a significant growth in wind and photovoltaic production is already foreseen by 2030. After that date, a wide deployment of offshore wind is expected with a significant decrease in cost. In a medium-long term scenario, with the massive expansion of renewable energy systems and the growing demand for hydrogen across multiple sectors, it is conceivable that some large-scale offshore wind farms (OWFs) could be exclusively dedicated to on-site green hydrogen production, thereby mitigating the impact on the electrical grid and simultaneously increasing hydrogen availability. This study reports the methods, assumptions, and results of a technical–economic analysis carried out for green hydrogen production from dedicated OWFs in two Italian offshore sites, one in Sicily and one in the Adriatic Sea. Despite the high uncertainty associated with carrying out this type of assessment for emerging technologies, the levelized costs obtained for dedicated offshore wind energy (approximately 70–80 EUR/MWh) and green hydrogen (approximately 5–6 EUR/kg) are in line with corresponding sector studies. Moreover, the simplified methodological approach developed is useful to analyse and compare other marine areas and different system configurations. Full article

This experimental study deals with the effect of the natural marine environment in the Adriatic Sea on the properties of the welded additively manufactured stainless steel AISI 316L. The welding of additively manufactured materials is of special interest to the maritime industry, which is seeking to introduce additive manufacturing technology in the repair and maintenance of ships and offshore installations. Three types of welded specimens were tested: a combination of two additively manufactured parts, a combination of additively manufactured and conventionally manufactured parts, and, for reference, a combination of two conventionally manufactured parts. The specimens were submerged below the sea for one, three, and six months. Once extracted, the specimens were tested for changes in mass, tensile strength, and surface morphology. The results show better behaviour of conventionally manufactured steel in the primary periods of exposure in terms of regaining tensile strength. EDS scans show the apparent influence of the sea, underlining the importance of conducting such experiments in the natural marine environment. The research highlights include exposure to the natural marine environment for prolonged periods and testing different additively and conventionally welded steel AISI 316L configurations. Full article

An oceanographic cruise from the southern Adriatic to the northern Ionian Sea in May 2013 allowed us to describe the spatial abundance and distribution of decapod crustacean larval assemblages with a multidisciplinary approach. Seventeen locations on the Apulian and Albanian shelves and offshore waters, including the Strait of Otranto, were sampled by a BIONESS electronic multinet. A swarm of zoeae (11 Brachyura taxa, mostly at first instar, with Xantho granulicarpus at 87%) was recorded in the neuston of the Italian side. Decapod larvae were concentrated in the first 20–30 m surface layer, strongly linked to the thermocline and generally above the Deep Chlorophyll Maximum (DCM), suggesting that they are carried by surface water circulation. The migratory behavior of decapod larvae in coastal stations is quite regular at between 20 and 60 m depths and independent of the time of day. In offshore stations, migration is compatible with the day–night cycle, where a minimum Weighted Mean Depth (WMD) value is evident at about 20 m at night. The availability of four satellite-tracked surface drifters in the same area and during the period of larvae presence presented a possibility to explore the link between the geographic dispersal of larvae and their surface circulation in successive days. Only one drifter crossed the south Adriatic, passing from the Italian to the Balkan neritic area, taking about 40 days. The actual genetic homogeneity of many Brachyura coastal species populations on opposite sides of the Adriatic Sea suggests the existence of a genetic connection that does not rely exclusively on larvae circulation and appears to be fueled by additional strategies of biological communication. Full article

Considering the role of phytoplankton in the functioning and health of marine systems, it is important to characterize its responses to a changing environment. The central Adriatic Sea, as a generally oligotrophic area, is a suitable environment to distinguish between regular fluctuations in phytoplankton and those caused by anthropogenic or climatic influences. This study provides a long-term perspective of phytoplankton assemblage in the central eastern Adriatic Sea, with 14 years of continuous time series data collected at two coastal and two offshore stations. The predominant phytoplankton groups were diatoms and phytoflagellates, but their proportion varied depending on the vicinity of the coast, as evidenced also by the distribution of chlorophyll a. In the coastal environment, the phytoplankton biomass was substantially higher, with a higher proportion of microphytoplankton, while small phytoplankton accounted for the majority of biomass in the offshore area. In addition, a decreasing trend in diatom abundance was observed in the coastal waters, while such trend was not so evident in the offshore area. Using a neural gas algorithm, five clusters were defined based on the contribution of the major groups. The observed increase in diversity, especially in dinoflagellates, which outnumber diatom taxa, could be a possible adaptation of dinoflagellates to the increased natural solar radiation in summer and the increased sea surface temperature. Full article

Zooplankton are a pivotal component of the pelagic community, and their abundance and distribution are often strongly dependent on environmental conditions at sea. However, climate change can pose significant challenges to planktonic organisms. Therefore, in this study, we tried to address the possible effect of short-term climatic anomalies on the zooplankton community in the North Adriatic Sea, comparing mesozooplankton composition in June between two years with very different temperature and rainfall levels, i.e., 2019 and 2022. Environmental conditions at sea were significantly different, since 2022 faced rising temperatures in the northern part of the area and higher salinity and lower chlorophyll values in coastal samples. Our data unveiled a community shift, from a Noctiluca-dominated community to a crustacean-dominated one, and revealed that even offshore areas can be subject to changes, despite having quite stable environmental parameters. Our findings confirmed the influence of river inputs and temperature on the Adriatic community’s distribution and composition, highlighting how climate-driven changes could have unpredictable effects on the whole Adriatic ecosystem. Indeed, each species has its own role in ecosystem functioning and climatic anomalies could uncouple the fine-scale connections that make up the pelagic trophic web. Full article

The energy produced from renewable sources (solar, wind, hydro, geothermal, and biomass) provides direct access to clean and safe energy. Offshore wind energy, generated through wind farms, has traditionally relied on fixed structures, whereas innovative floating structures have been commercially applied since 2017. This study investigates offshore areas in Montenegro suitable for wind farm construction. Research on average annual wind speeds has successfully identified a surface area deemed suitable for constructing a wind farm in the Montenegrin part of the Adriatic Sea. Analysis of available bathymetric databases has pinpointed technical solutions for the supporting structures of wind turbines required to construct an offshore wind farm. Applying an assessment method to the defined surface of Montenegrin waters, seven blocks have been identified as suitable for wind farm construction. The research results indicate that wind farms can be built in Montenegrin waters with a technical potential corresponding to a total capacity of 2299.794 MW, which includes 2034.48 MW for floating structures, 126.759 MW for fixed structures, and 138.555 MW for jacket-fixed structures. Full article

Studies based on fish early life stages can provide information on spawning grounds and nursery areas, helping to determine the implications for stock biomass fluctuations of recruitment variability. This study describes the composition, abundance, spatial distribution and differences in day/night vertical distribution of ichthyoplankton in the southern Adriatic Sea. Samples were collected within the framework of the COCONET project (Towards COast to COast NETworks of marine protected areas) from 9 to 18 May 2013 by the R/V Urania, using the electronic multinet EZ-NET BIONESS (Bedford Institute of Oceanography Net Environmental Sampling System). A total of 20 species, belonging to 20 genera and 13 families, were identified. Of the collected larvae, 74.3% were meso- or bathypelagic species, 24.7% were epipelagic and 0.9% were demersal. The community was dominated by Gonostomatidae, followed by Engraulidae, Myctophidae and Photychthaidae. The most abundant species was Cyclothone braueri (45.6%), followed by Engraulis encrasicolus, Ceratoscopelus maderensis, Cyclothone pygmaea, Vinciguerria attenuata and Myctophum punctatum. An inshore/offshore increasing gradient in biodiversity and abundance was observed. Different weighted mean depths (WMDs) were observed for larvae and juveniles. No diel vertical migrations were observed. The high abundance of meso- or bathypelagic species in the upper 100 m confirms the epipelagic zone as an important environment for the development of the larval stages of these fish. Full article

The Aiza research area covers over 650 km² of the northern Adriatic offshore, a common Adriatic foreland of the older Dinarides on the NE, and the younger Apennines on the SW. High-quality 3D reflection seismic data were used to investigate the area’s Mesozoic to Cenozoic tectono-stratigraphic evolution. Four main seismo-stratigraphical horizons were recognized: Base of Carbonate Platform (BCP), Top of Carbonate Platform (TCP), Messinian Erosional Surface (MES), and a Plio-Quaternary horizon (PlQh), as well as the dominant faults. The results depict the geological setting and tectonic evolution of the area. A long-lasting (Jurassic to Cretaceous) stable NW-SE striking platform margin evolved probably along the inherited Triassic normal fault. The marginal belt of the platform was affected during the Late Cretaceous to Palaeogene by extension and opening of the intra-platform basin, probably on the southern limb of the then developing Dinaric forebulge. The transverse fault system (Kvarner fault) was probably reactivated as a strike-slip zone during the late Miocene tectonic reorganization. The area was tilted to the SW during the Pliocene, in the distal foreland of the progressively northward propagating Northern Apennines. Sub-horizontal late Quaternary cover of Dinaric and Apenninic structures could imply active subsidence of the foreland in between nowadays sub-vertically exhuming neighboring orogenic belts. Full article

New hypotheses for reusing platforms reaching their end-of-life have been investigated in several works, discussing the potential conversions of these infrastructures from recreational tourism to fish farming. In this perspective paper, we discuss the conversion options that could be of interest in the context of the current energy transition, with reference to the off-shore Italian scenario. The study was developed in support of the development of a national strategy aimed at favoring a circular economy and the reuse of existing infrastructure for the implementation of the energy transition. Thus, the investigated options include the onboard production of renewable energy, hydrogen production from seawater through electrolyzers, CO₂ capture and valorization, and platform reuse for underground fluid storage in depleted reservoirs once produced through platforms. Case histories are developed with reference to a typical, fictitious platform in the Adriatic Sea, Italy, to provide an engineering-based approach to these different conversion options. The coupling of the platform with the underground storage to set the optimal operational conditions is managed through the forecast of the reservoir performance, with advanced numerical models able to simulate the complexity of the phenomena occurring in the presence of coupled hydrodynamic, geomechanical, geochemical, thermal, and biological processes. The results of our study are very encouraging, because they reveal that no technical, environmental, or safety issues prevent the conversion of offshore platforms into valuable infrastructure, contributing to achieving the energy transition targets, as long as the selection of the conversion option to deploy is designed taking into account the system specificity and including the depleted reservoir to which it is connected when relevant. Socio-economic issues were not investigated, as they were out of the scope of the project. Full article

Underground fluid storage is gaining increasing attention as a means to balance energy production and consumption, ensure energy supply security, and contribute to greenhouse gas reduction in the atmosphere by CO₂ geological sequestration. However, underground fluid storage generates pressure changes, which in turn induce stress variations and rock deformations. Numerical geomechanical models are typically used to predict the response of a given storage to fluid injection and withdrawal, but validation is required for such a model to be considered reliable. This paper focuses on the technology and methodology that we developed to monitor seabed movements and verify the predictions of the impact caused by offshore underground fluid storage. To this end, we put together a measurement system, integrated into an Autonomous Underwater Vehicle, to periodically monitor the seabed bathymetry. Measurements repeated during and after storage activities can be compared with the outcome of numerical simulations and indirectly confirm the existence of safety conditions. To simulate the storage system response to fluid storage, we applied the Virtual Element Method. To illustrate and discuss our methodology, we present a possible application to a depleted gas reservoir in the Adriatic Sea, Italy, where several underground geological formations could be potentially converted into storage in the future. Full article

Renewable energy is one of the main components of a sustainable world and its future. The consumption of electricity from renewable sources in Croatia has an impressive rate of 53.5%, but offshore wind turbines (OWT) have not yet been installed in the Adriatic Sea. The aim of this study is to determine the possibilities for offshore wind farm (OWF) positioning in the Croatian part of the Adriatic Sea using marine spatial planning (MSP). Initial research to determine the points of interest was conducted based on wind speed. The authors established ten possible points for further research. Subsequently, different parameters were used as inputs for exclusion. The Fuzzy Analytic Hierarchy Process (AHP) method was used to calculate the weighting coefficients for a suitable set of criteria, exactly six of them. Using a combination of geoinformation system (GIS) analysis and weighting coefficients established through Fuzzy AHP, four points were established as suitable for OWF installation in Croatia. Finally, the Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method was used to select the best order for OWF positioning in the eastern part of the Adriatic Sea. To conclude, there are not many options for OWF positioning in Croatia. Furthermore, it is clear that they exist and should be explored further. Full article

The environmental contours represent an approach for defining extreme environmental conditions, resulting in extreme responses of marine structures with a given return period. Over the past decade, an increasing number of studies have been developed dealing with the methods for defining environmental contours and enhancing their practical application in different marine environments. In the present study, environmental contours describing significant wave heights and peak wave periods are created for the Adriatic Sea. This small semi-enclosed sea basin within the Mediterranean Sea encounters increasing maritime and offshore activities. Considering also a great but still unused potential for the installation of renewable energy facilities, the main motives for the presented study are concluded. The environmental contours are established based on 24 years of hindcast wave data extracted from the WorldWaves database. Joint distributions consisting of the marginal distribution of significant wave height and conditional distributions of peak wave periods are used as a basis for the creation of environmental contours using the IFORM and ISORM methods. Return periods of 1 year, 25 years, and 100 years are considered relevant for the marine operation, design of ships, and offshore structures, respectively. A possibility of environmental contour practical application to the calculation of global wave loads upon ship structures is presented. Based on the uncertainty assessment performed, conservative environmental contours for the whole Adriatic are also presented. Full article

We studied the long-term features of earthquakes caused by a fault system in the northern Adriatic sea that experienced a series of quakes beginning with two main shocks of magnitude 5.5 and 5.2 on 9 November 2022 at 06:07 and 06:08 UTC, respectively. This offshore fault system, identified through seismic reflection profiles, has a low slip rate of 0.2–0.5 mm/yr. As the historical record spanning a millennium does not extend beyond the inter-event time for the largest expected earthquakes ($M\simeq 6.5$), we used an earthquake simulator to generate a 100,000-year catalogue with 121 events of $M_w\ge 5.5$. The simulation results showed a recurrence time ($T_r$) increasing from 800 yrs to 1700 yrs as the magnitude threshold increased from 5.5 to 6.5. However, the standard deviation $\sigma$ of inter-event times remained at a stable value of 700 yrs regardless of the magnitude threshold. This means that the coefficient of variation ($C_v=\sigma /T_r$) decreased from 0.9 to 0.4 as the threshold magnitude increased from 5.5 to 6.5, making earthquakes more predictable over time for larger magnitudes. Our study supports the use of a renewal model for seismic hazard assessment in regions of moderate seismicity, especially when historical catalogues are not available. Full article

The Mediterranean is one of the most overfished seas of the world where mesopredators are severely threatened. The trophic strategies of four pelagic species that inhabit the Adriatic Sea (Scomber spp. and Trachurus spp.) were investigated through an integrated approach of stomach contents and stable isotopes analyses. Our study demonstrated that Scomber colias feeds mainly on strictly pelagic prey, with fish larvae as a secondary prey in the Southern Adriatic Sea, while S. scombrus feeds on prey belonging to higher trophic levels. Smaller specimens of Trachurus mediterraneus have a diet mainly based on pelagic prey, while larger fishes rely on prey such as benthic decapods, showing an ontogenetic shift in the diet of the species. Trachurus trachurus shows a preference for offshore and deeper areas and a diet such as that of its congeneric, but no clear ontogenetic shift was observed. This spatial segregation allows the co-existence of these two species of Trachurus. Scomber colias mainly inhabits southern areas and S. scombrus shows a preference for the northern sectors. This latitudinal gradient avoids the overlap of their trophic niches. Bayesian mixing models confirmed that the trophic niches of these species only partially overlap in the middle of the trophic web. Full article

The performance of both the tectonic uplift and of the 4th-order glacial eustatic sea level fluctuations in controlling the stratigraphic architecture of Quaternary lowstand prograding wedges of the Salento continental shelf (Southern Adriatic sea, Italy) during a time interval spanning from the Middle Pleistocene to the Holocene has been pointed out through the interpretation of high-resolution seismic reflection profiles and their correlation to the curves of the isotopic stratigraphy. Three main transgressive surfaces of erosion (RS1, RS2 and RS3) punctuate the stratigraphic architecture of the Salento continental shelf, separating Quaternary lowstand prograding wedges between them. All along the Middle Pleistocene, increasing the tectonic uplift of the Puglia offshore, combining with 4th-order glacio-eustatic variations, have dealt with the pattern of a broad forced regression prograding wedge, favoring a platform progradation of approximately 15 km. The architectural stacking patterns of the overlying Late Pleistocene and Holocene prograding wedges are controlled by 4th-order glacio-eustatic sea level changes, allowing for the formation of incomplete depositional sequences. In this period, the eustatic signature overcomes the tectonic mark, implying a decline in the uplift of the Apulian foreland in the course of the final 250 ky. Full article