Aeolian Islands Research Articles

Ecology and Phenology of the Subtidal Brown Alga Sargassum furcatum (Ochrophyta, Fucales), a Likely Non-Indigenous Species from the Mediterranean Sea

This study provides new insights regarding the ecology and phenology of the likely non-indigenous canopy-forming species Sargassum furcatum on the central-eastern coast of Sicily (Italy, Central Mediterranean). This species was described for St. Thomas (Virgin Islands), and it was reported for the first time in the Mediterranean in 1995 in the Chafarinas islands (Spain, western Mediterranean). After the first report, this species was found in 2021 in several sites located along the eastern coast of Sicily (Italy), along the French Mediterranean coastline, in Corsica, and recently also in the Aeolian Islands (Italy). No phenological studies on this species have been ever carried out in the Mediterranean Sea. To conduct this study, a visual census activity was performed in three sites along the Ionian coast of Sicily throughout 2023, during which the length of the main axis of S. furcatum specimens was measured and the frequency of findings of the species during the year was noted. In this study, it was observed that S. furcatum shows a wide adaptability in terms of range of depth, temperature, light exposure, and type of substrate. Since the distribution of this species is mostly centralized in the western Atlantic Ocean, it is likely that S. furcatum entered the Mediterranean through the Gibraltar Strait. Consequently, the entrance of this species in this Basin could be further proof of the ongoing seawater warming and tropicalization of Mediterranean waters. From this point of view, it is important to keep monitoring the dynamics of S. furcatum in the Mediterranean Sea in order to understand its putative impacts on autochthonous communities.

Emergency management and risk reduction measures during the Vulcano (Aeolian Islands) unrest 2021–2023

Emergency management and risk reduction measures during the Vulcano (Aeolian Islands) unrest 2021–2023

Seeps and Tectonic Structure of the Hydrothermal System of the Panarea Volcanic Complex (Aeolian Islands, Tyrrhenian Sea)

High-definition bathymetry mapping, combined with the measurement of dissolved benthic fluxes and water column biogeochemical properties, allows for a description of new biogeochemical processes around the Panarea Volcanic island. Investigations focused on the CO2 releases from the bottom sea on the east of the Panarea volcanic complex provided insights into the geological setup of the marine area east and south of the Panarea Island. Between the Panarea Island and the Basiluzzo Islet lies a SW-NE-stretching graben structure where a central depression, the Smoking Land Valley, is bounded by extensional faults. Abundant acidic fluids rich in dissolved inorganic Carbon are released on the edges of the graben, along the extensional faults, either diffusely from the seafloor, from hydrothermal chimneys, or at the center of craters of different sizes. The precipitation of iron dissolved in the acidic fluids forms Fe-oxyhydroxides bottom sea crusts that act as a plug, thus preventing the release of the underlying gases until their mounting pressure generates a bursting release. This process is cyclic and results in intermittent gas release from the bottom, leaving extinct craters and quiescent chimneys. The measurement of dissolved benthic fluxes allowed us to estimate the volcanic DIC venting at 15 Mt of CO2 over the past 10,000 years. The fluxes are not distributed homogeneously but rather concentrate along fractures and fault planes, which facilitate their rise to the seafloor. The acidic fluids released affect the chemical properties and structure of the water column through the formation of layers with a lower pH under the pycnocline, which can limit volcanic CO2 release to the atmosphere. Further and continuous monitoring and investigation of the area are needed in order to complete a thorough picture of the variations in fluid releases through time and space. The importance of such monitoring lies in the development of a new method for detecting and quantifying the diffusive dissolved benthic fluxes on a volcanic sea bottom affected by hydrothermal seeps.

Contribution to the floristic knowledge of Lipari and Panarea Islands (Sicilia, Italy)

The inventory of the taxa collected in 2022 during the annual field trip of the Working Group for Floristics, Systematics and Evolution of the Italian Botanical Society is reported. The field trip was held from 19th to 22th April in the islands of Lipari and Panarea (Aeolian Islands, Sicilia). Overall, 1,664 herbarium specimens were deposited in public and private herbaria. The flora documented for the studied area amounts to 386 specific and subspecific taxa, belonging to 241 genera and 74 families. Centaurea aeolica, Helichrysum litoreum (Asteraceae), and Dianthus rupicola subsp. aeolicus (Caryophyllaceae) were the only three Italian endemics found in the study area, whereas 48 alien taxa were recorded. Dimorphotheca ecklonis (Asteraceae), Nassella tenuissima (Poaceae), Solanum torvum (Solanaceae), and Viola wittrockiana (Violaceae) are casual alien species new to Sicilia, whereas Oenothera odorata (Onagraceae) is a new naturalized alien species for the Italian vascular flora.

Deciphering the evolvement of microbial communities from hydrothermal vent sediments in a global change perspective

Microbial communities first respond to changes of external environmental conditions. Observing the microbial responses to environmental changes in terms of taxonomic and functional biodiversity is therefore of great interest, particularly in extreme environments, where the already extreme conditions can become even harsher. In this study, sediment samples from three different shallow hydrothermal vents in Levante Bay (Vulcano Island, Aeolian Islands, Italy) were used to set up microcosm experiments with the aim to explore the microbial dynamics under changing conditions of pH and redox potential over a 90-days period. The leading hypothesis was to establish under microcosm conditions whether the starting microbial communities of the sediments evolved differently depending on their origin. To profile the dynamics of microbial populations over time, biodiversity, enzymatic profile, total cell abundance estimations, total/respiring cell ratio were estimated by using different approaches. An evident change in the microbial community structure was observed, mainly in the microcosm containing the sediment from the most acidified site, which was characterized by a highly diversified microbial community (in prevalence composed of Thermotoga, Desulfobacterota, Planctomycetota, Synergistota and Deferribacterota). An increase in microbial resistant forms (e.g., spore-forming species) with anaerobic metabolism was detected in all experimental conditions. Differential physiological responses characterized the sedimentary microbial communities. Proteolytic activity appeared to be stimulated under microcosm conditions, whereas the alkaline phosphatase activity was significantly depressed at low pH values, like those that were measured at the station showing intermediate pH-conditions. The results confirmed a differential response of microbial communities depending on the starting environmental conditions.

The “Return” of Southern Italo-Romance Tonna: From Pseudocoordination to Adverb. A Case Study in Grammaticalization

The present work constitutes an initial look at the use of tonna, an invariable form of tornare ‘return’, used as a relatively uncommon V1 in southern Italo-Romance pseudocoordination structures. Along with losing its ability to inflect, grammaticalization of tornare, frequent across Italo-Romance, has consisted in its shift from lexical motion verb to a functional one with repetitive aspectual value, i.e. tonna mmanciu ‘I eat again’. This paper presents novel data from the variety of Eolian (Italo-Romance dialect of the Eolian Islands), which shows constructions previously unattested with invariable V1s, such as its embedding under functional verbs in non-finite clauses. A cartographic approach building on existing accounts of pseudocoordination V1s – centered on Cinque’s (1999, 2006) hierarchy of functional projections – leads us to consider two overarching explanations for tonna: that it is (a) a functional, aspectual head (in one of the two “repetitive” projections, viz. AspRepetitive(I), AspRepetitive(II)) or (b) an adverb, a specifier in these respective projections. Ultimately, the conclusion that it has (re)grammaticalized to the point of becoming a (deficient) adverb in the lower AspRepetitive(II) proves to be the most convincing from a theoretical perspective. A potential structural consequence is the syncretic status of the AspRepetitive(II) head.

A review of the tectonic, volcanological and hazard history of Vulcano (Aeolian Islands, Italy)

AbstractVulcano is one of the seven volcanic islands composing the Aeolian Islands archipelago (Southern Italy), which also includes three other active volcanoes. The island was originally a stratovolcano like Stromboli; afterwards, its shape turned towards a complex structure composed of several volcanic landforms of different sizes. This is due to the great variability of the tectonic and volcanic phenomena, presently showing a volcano made by two calderas, a lava dome complex and two small active cones. The largest of them is the tuff cone of La Fossa, hosted in the middle of a 3‐km‐wide caldera structure (La Fossa caldera), whose borders are visible on the southern and western sides of the island. Its last eruption occurred in 1888–1890. At present, Vulcano is characterized by weak shallow seismicity and intense fumarolic activity mainly concentrated within the crater of the La Fossa cone and along its rims during a recent unrest phase started in 2021, and measured with a multiparametric monitoring network.

Development of a Vessel Scheduling Optimization Model to improve Maritime Transport sustainability

The social and economic development of the islands is generally dependent on the interconnection level with the mainland obtained through maritime transport services. When connecting many islands, the route planning is essential and typically a variety of constraints must be considered. Various optimization methods have been established to improve cost-efficiency but today environmental concerns, like the reduction of CO2 emissions, have become mandatory. This paper proposes a vessel scheduling optimization model able to simultaneously consider compulsory and optional tasks and vehicle-dependent profits. The algorithm was applied to seven islands of the Tyrrhenian Sea located in front of Sicily, named “Aeolian Islands”. Considering the regional requirements in terms of minimum number of routes and maximum fare prices for each season, this research compared the optimal vessels option obtained maximizing the profit with the one obtained minimizing the emissions. In particular, we have conducted three different analyses, in the first one we have considered only the mandatory routes while the second one was carried out identifying a series of potentially attractive additional activities based on historical demand data provided by the company that currently manages the service. Finally, the third analysis addresses a scenario where older fuel-powered vessels were replaced with hybrid electric ones.

Mapping the microbial diversity associated with different geochemical regimes in the shallow-water hydrothermal vents of the Aeolian archipelago, Italy.

Shallow-water hydrothermal vents are unique marine environments ubiquitous along the coast of volcanically active regions of the planet. In contrast to their deep-sea counterparts, primary production at shallow-water vents relies on both photoautotrophy and chemoautotrophy. Such processes are supported by a range of geochemical regimes driven by different geological settings. The Aeolian archipelago, located in the southern Tyrrhenian sea, is characterized by intense hydrothermal activity and harbors some of the best sampled shallow-water vents of the Mediterranean Sea. Despite this, the correlation between microbial diversity, geochemical regimes and geological settings of the different volcanic islands of the archipelago is largely unknown. Here, we report the microbial diversity associated with six distinct shallow-water hydrothermal vents of the Aeolian Islands using a combination of 16S rRNA amplicon sequencing along with physicochemical and geochemical measurements. Samples were collected from biofilms, fluids and sediments from shallow vents on the islands of Lipari, Panarea, Salina, and Vulcano. Two new shallow vent locations are described here for the first time. Our results show the presence of diverse microbial communities consistent in their composition with the local geochemical regimes. The shallow water vents of the Aeolian Islands harbor highly diverse microbial community and should be included in future conservation efforts.

Financial Analysis of a Desalination–Wastewater Recycle Plant Powered by a DC-DC Photovoltaic-Batteries System on the Aeolian Islands, Italy

The scarcity of drinking water is an increasingly pressing issue in many regions of the world, even in areas up till now considered developed. Climate change deprives many populations of the amount of water necessary for human consumption and traditional crops. Therefore, finding new water sources and making their usage more efficient and able to adapt to new environmental conditions without worsening the situation with further pollution is becoming mandatory. In the case study considered here, set on the Italian island of Vulcano in the Central Mediterranean, we propose the economic analysis and financial sustainability of plants for the desalination and recycled wastewater, powered by a DC-DC photovoltaic tracker system with silicon crystal panels sustained by a daily pack of lithium batteries. We present an estimation of the necessary budget, and propose a mix of traditional and innovative financial instruments to construct and analyse the economic trends of the installations over 30 years, considering the specific area price levels, salaries and interest rates. Finally, through the net present value index, we evaluate the financial sustainability of the entire operation, namely, identifying the circumstances when funding and building these plants in areas as remote as the one considered here is cost-effective.

The Thermal Plumbing System of Stromboli Volcano, Aeolian Islands (Italy) Inferred From Electrical Conductivity and Induced Polarization Tomography

AbstractWe performed the first 3D island‐scale tomography of the electrical conductivity of Stromboli volcano (Aeolian Islands, Italy) using 2D acquisition lines (37.2 km) and a total of 18,880 measurements and 2,402 unique electrode locations. This 3D data set was inverted using a Gauss‐Newton algorithm, parallel‐processing on an unstructured tetrahedral mesh containing 678,420 finite‐element nodes and 3,580,145 elements to account for the topography of the volcanic island. The tomogram exhibits a conductive body (10−2–1.0 S m−1) consistent with the location of CO2 and temperature anomalies observed at the ground surface. It corresponds to the hydrothermal system with high electrical conductivity associated with alteration. In order to confirm this interpretation, a 2.5D large‐scale induced polarization tomography was performed crossing the volcano. The joint interpretation of the conductivity and normalized chargeability is done with a petrophysical model previously tested and verified at both shield‐ and strato‐volcanoes. This model implies that alteration (through the effect of the cation exchange capacity associated with clay minerals and zeolites) plays a strong role in both controlling the electrical conductivity and normalized chargeability at Stromboli volcano. A temperature tomogram, derived from the geoelectrical measurements, is consistent with surface temperature anomalies and the Very Long Period (VLP) seismicity related to the mild‐explosive activity. This survey displays at 600 m a.s.l. a lateral shift in the highest temperature location, also corresponding to the source of VLP seismicity. Structural boundaries have a major role in the hottest hydrothermal fluids rising below the active crater terrace of Stromboli volcano.

Advanced argillic alteration at Cave di Caolino, Lipari, Aeolian Islands (Italy): Implications for the mitigation of volcanic risks and the exploitation of geothermal resources

Four sites in the western sector of Lipari Island with still active hydrothermal activity are here considered. The petrography (mesoscopic observations and XRPD) and geochemistry (major, minor and trace elements chemistry) of ten representative and extremely altered volcanic rocks were characterized. Two types of parageneses of altered rocks are discriminable, one rich in silicate phases (opal/cristobalite, montmorillonite, kaolinite, alunite and hematite) and one in sulphates (gypsum, plus minor amounts of anhydrite or bassanite). The altered silicate-rich rocks are rich in SiO2, Al2O3, Fe2O3 and H2O, and depleted in CaO, MgO, K2O and Na2O, while the sulphate-rich ones are extremely enriched in CaO and SO4 in comparison with local unaltered volcanic rocks. The content of many incompatible elements is similar in altered silicate-rich rocks and lower in sulphate-rich ones with respect to the pristine volcanic rocks; conversely, almost all REEs are markedly enriched in silicate-rich rocks and heavy REEs are enriched in sulphate-rich altered rocks compared to unaltered volcanic rocks.Reaction path modelling of basaltic andesite dissolution in local steam condensate predicts the production of amorphous-silica, anhydrite, goethite, and kaolinite (or smectites and saponites) as stable secondary minerals and alunite, jarosite, and jurbanite as ephemeral minerals. Considering possible post-depositional reactions and admitting that the presence of two distinct parageneses is apparent, since gypsum is prone to form large crystals, it can be concluded that there is an excellent agreement between the alteration minerals occurring in nature and those predicted by geochemical modelling. Consequently, the modelled process is the main responsible for the production of the advanced argillic alteration assemblage of “Cave di Caolino” on Lipari Island. Since rock alteration is sustained by the H2SO4 solution produced by hydrothermal steam condensation, there is no need to invoke the involvement of SO2-HCl-HF-bearing magmatic fluids, in line with the absence of fluoride minerals.

Freight Distribution in Small Islands: Integration between Naval Services and Parcel Lockers

Freight transportation in urban areas represents an essential activity from the standpoint of economic development; in recent years, the spread of e-commerce (also accelerated by COVID-19) has contributed to increasing the demand for freight distribution over short distances. In most cities, the approaches and measures are often based on new technologies. Nevertheless, today there are contexts wherein delivery operations represent critical tasks to be solved. Furthermore, low accessibility areas, such as small islands, present further problems due to their exclusive dependence on maritime links (and often low-reliability services). This paper tackles this topic, formulating and solving a distribution problem by linking shipping services with last-mile distribution operated by means of an automatic delivery service (parcel lockers). A test application is proposed by considering the small island of Lipari in the archipelago of the Aeolian islands (Sicily, Southern Italy). The results show that such a type of service could reduce the user’s waiting time when compared to traditional home deliveries.

Quantitative morphology and mtDNA reveal that Lasius maltaeus is not endemic to the Maltese Islands (Hymenoptera, Formicidae)

Lasius maltaeus Seifert, 2020 was recently described as a Maltese endemic ant based on quantitative morphology, after decades of uncertainties over the identity of the local population, which has a phenotype resembling L. emarginatus (Olivier, 1791). At the same time, Sicilian L. emarginatus populations were discovered to diverge in their mitochondrial DNA to a degree that suggested heterospecificity. Considering the biogeographic similarity of Malta and Sicily, with land bridges connecting them repeatedly until the last glacial maximum, we questioned the assumption that L. maltaeus was endemic to Malta. We integrated quantitative morphology and mtDNA in the study of the Maltese and southern Italian populations phenotypically close to L. emarginatus. We discovered that the range of L. maltaeus extends over most of Sicily, while the true L. emarginatus replace it in the north-eastern sector of the island, the nearby Aeolian Islands, and the Italian peninsula. The distributions of L. emarginatus and L. maltaeus in Sicily follow biogeographic patterns recalling the island’s complex paleogeographic history. Further investigations should verify the existence of truly Maltese endemic ants, since the status of other allegedly endemic species is not strongly supported.

Paleogenetic analysis and radiocarbon dating on skeletal remains from the Roman necropolis of Contrada Diana (Lipari Island, Sicily)

Lipari, the largest of the Aeolian Islands, is located in the southern Tyrrhenian Sea. Archeological evidence suggests an early human occupation starting from the Neolithic period. The island, favored by its volcanic history, was an important crossroads of cultures and commerce exchanges during prehistory up to Greek and Roman dominations. In this study, we present multidisciplinary analysis results on four skeletal remains from the necropolis of Contrada Diana attributed to the Roman period. By using Next Generation Sequencing technology we identified the biological sex and reconstructed the complete mitochondrial genome for two individuals. We retrieved the first ancient L3e5a lineage that is today present only in North and Central Africa. In addition, a 14C dating of 2,030 ± 45 years BP was obtained for one individual. A previous ancient DNA study has highlighted a genetic link between Sicily and the African continent at least from the Bronze Age. Our results, documenting the existence of contacts between Lipari and Africa during Roman influence, are particularly relevant to better understand the peopling of the Aeolian Archipelago when the island was a sea route of primary importance for the trade in the Mediterranean.

Non-invasive investigation on pigments of the Aeolian Islands Neolithic pottery

The Neolithic painted pottery, spread all over southern Italy, is considered as an important chronological indicator for the development of VI-V millennium BC prehistoric settlements and cultural traditions. The goal of this work is to contribute to the study of this ceramic class through the chemical characterization of some samples coming from the Aeolian Islands. 16 different sherds have been selected and the pigments preserved in their decorations analyzed via non-invasive techniques: Fiber Optical Reflectance Spectroscopy (FORS), X-ray Fluorescence (XRF), Raman Spectroscopy and Infrared Spectroscopy (FT-IR). The different pigments, some of which no longer clearly visible to the naked eye (red ochre and raw umber) were identified, while the FT-IR data provided information about the pottery differentiation.

Observing and modeling long-term persistence of P. noctiluca in coupled complementary marine systems (Southern Tyrrhenian Sea and Messina Strait)

In the Mediterranean Sea, the Strait of Messina (MS) is a very peculiar area, connecting highly different regions and representing a privileged observatory for an early comprehension and assessment of ecosystems shifts. It is hypothesized that the outbreaks observed near the coast of many sites in the Mediterranean Sea may be the result of transport of permanent populations of P. noctiluca in pelagic waters to the coast, caused by specific hydrodynamic conditions. By both visual observations and numerical experiments our objective is twofold: (A) to help clarify whether the basin of the Aeolian Islands Archipelago (AIA), in the Southern Tyrrhenian Sea (STS), may be the site from which large populations of P. noctiluca are transported to the MS, and (B) to evaluate whether the upwelling turbulent system of the MS can be an energetic opportunity for this species. It should offer a rich habitat without jeopardizing the overall survival of the population, that is subject to stranding due to strong currents. Although very different, the two involved ecosystems (AIA and MS ) are complementary for the success of Pelagia noctiluca life cycle. Outputs obtained by coupling the 3D hydrodynamic model (SHYFEM) with a Lagrangian particle tracking model support the hypothesis of a connectivity between these two ecosystems, particularly in the first half of the year, indicating the coastal areas around the AIA as potential optimal source location for Pelagia larval stages. We support the very attractive hypothesis that two connected systems exist, the former one favours Pelagia's reproduction and acts as a nursery and the latter favours its growth due to higher productivity. We speculate that the reproductive population of the AIA is not permanent, but is renewed every year by individuals who have fed and quickly grown in the MS and who are passively transported by downwelling along canyon "corridors".

On de Mundo and pseudo‐Aristotle, a geoarchaeological analysis

Abstract“De Mundo” (“On the Cosmos”), an influential ancient anonymous treatise (manuscript) covering natural phenomena and philosophical ideas, is assigned by the majority of investigators to pseudo‐Aristotle, an unknown philosopher of Roman times mimicking Aristotle. This article focuses on differences in the geological content between “Meteorologica” (“Meteorology”), the famous work of Aristotle on Natural Sciences, and “de Mundo.” Four themes are examined: the evolution of the legend of the 373 BC earthquake and tsunami at Helike and Boura (Gulf of Corinth, Greece) based on new geoarchaeological and archaeological evidence, volcanic eruptions of the Aeolian Islands and Etna, but not of Vesuvius (Italy), neurotoxic effects of gas seepage, mostly in oracles, and the style of referencing to geological information. The new geoarchaeological evidence permits the dating of “de Mundo” in the first century AD, thereby refining previous interpretations, and implies no evidence of change in Aristotle's philosophical and geographical ideas at the end of his life. The overall analysis provides an explanation for the legend of the catastrophe of Helike, and it highlights the potential of geoarchaeological methods to provide new insights even into literary, philosophical, and geographical issues, and the dating of various ancient manuscripts.

Diversity and distribution of beetles in a Mediterranean volcanic archipelago: an updated checklist of the Coleoptera of the Aeolian Islands (Sicily, Italy)

Diversity and distribution of beetles in a Mediterranean volcanic archipelago: an updated checklist of the Coleoptera of the Aeolian Islands (Sicily, Italy)

Thermophilic Hydrocarbon-Utilizing Bacilli from Marine Shallow Hydrothermal Vents as Producers of Biosurfactants

The exploitation of thermophilic hydrocarbon-utilizing bacilli could provide novel environmentally friendly surfactants. In this work, 80 thermophilic bacilli isolated from shallow hydrothermal vents of the Eolian Islands (Italy) were screened for their ability to utilize hydrocarbons and produce biosurfactants (BSs). Among them, 15 strains grew with kerosene or gasoline (2% v/v) as the only carbon and energy source, and most of them were positive to the methylene blue agar as prescreening assay for BSs production and displayed emulsifying activity. The cell-free supernatants (CFSs) from two selected strains, Bacillus licheniformis B3-15 and Bacillus horneckiae SBP3, were both surface active and able to emulsify different hydrocarbons and vegetable oils. BSs from B3-15 (910 mg L−1) and SBP3 (950 mg L−1) were chemically different surfactin-like lipopeptides, with specific mineral-, castor- and crude oil removal ability from the cotton matrix. CFSs from the 15 thermophilic strains, which harbor both lipolytic and surfactant abilities, could be suitable for industrial-based applications and environmental issues, such as oil recovery and removal from polluted areas or surfaces, (e.g., oil pipelines, bilge tankers, or industrial silos), whereas the crude BSs, as high-value compounds, may be used in different fields of application, as detergent, cosmeceutical, and pharmaceutical industries.