Aeolian Archipelago Research Articles

On the Monitoring of Small Islands Belonging to the Aeolian Archipelago by MT-InSAR Data

AbstractThe aim of the present work is to evaluate the performance of several MT-InSAR techniques based on satellite SAR data in monitoring ground deformation phenomena affecting complex scenarios such as small islands of volcanic origin. To such purpose, PS, SBAS and IPTA approaches are applied in the study of Lipari, Salina and Vulcano islands belonging to the Aeolian archipelago, southern Tyrrhenian Sea, Italy. The outcomes retrieved from each technique are then discussed in terms of intrinsic features, spatial coverage, linear trend and coherence. Moreover, the accuracy of PS, SBAS and IPTA results are evaluated by comparison with in-situ measurements from the GNSS network managed by INGV-OE and private operators considering different metrics. Experimental results show that in this case there is no preferred MT-InSAR technique in an absolute way but each of them has strengths and drawbacks that have to be taken into account in the monitoring of complex scenarios.

Gene-centered metagenome analysis of Vulcano Island soil (Aeolian archipelago, Italy) reveals diverse microbial key players in methane, hydrogen and sulfur cycles

The Aeolian archipelago is known worldwide for its volcanic activity and hydrothermal emissions, of mainly carbon dioxide and hydrogen sulfide. Hydrogen, methane, and carbon monoxide are minor components of these emissions which together can feed large quantities of bacteria and archaea that do contribute to the removal of these notorious greenhouse gases. Here we analyzed the metagenome of samples taken from the Levante bay on Vulcano Island, Italy. Using a gene-centric approach, the hydrothermal vent community appeared to be dominated by Proteobacteria, and Sulfurimonas was the most abundant genus. Metabolic reconstructions highlight a prominent role of formaldehyde oxidation and the reverse TCA cycle in carbon fixation. [NiFe]-hydrogenases seemed to constitute the preferred strategy to oxidize H2, indicating that besides H2S, H2 could be an essential electron donor in this system. Moreover, the sulfur cycle analysis showed a high abundance and diversity of sulfate reduction genes underpinning the H2S production. This study covers the diversity and metabolic potential of the microbial soil community in Levante bay and adds to our understanding of the biogeochemistry of volcanic ecosystems.

Essential Oil Emulsion from Caper (Capparis spinosa L.) Leaves: Exploration of Its Antibacterial and Antioxidant Properties for Possible Application as a Natural Food Preservative.

This study explored, for the first time, the chemical composition and in vitro antioxidant and antibacterial activities of a caper leaf essential oil (EO) emulsion for possible food applications as a natural preservative. The EO was extracted by hydrodistillation from the leaves of Capparis spinosa growing wild in the Aeolian Archipelago (Sicily, Italy) and exhibited a pungent, sulphurous odour. The volatile fraction of the emulsion, analysed by SPME-GC-MS, consisted of over 100 compounds and was dominated by compounds with recognised antibacterial and antioxidant properties, namely dimethyl tetrasulfide (18.41%), dimethyl trisulfide (12.58%), methyl isothiocyanate (7.97%), and terpinen-4-ol (6.76%). The emulsion was effective against all bacterial strains tested (Listeria monocytogenes, Staphylococcus aureus, Escherichia coli, Salmonella enterica subsp. enterica serovar Enteritidis, Pseudomonas fluorescens), with L. monocytogenes exhibiting the lowest minimum inhibitory concentration (MIC = 0.02 mg/mL) while E. coli had the highest (MIC = 0.06 mg/mL). The emulsion had a good DPPH (2,2-diphenyl-1-picrylhydrazine) radical scavenging activity that was dose-dependent and equal to 42.98% at the 0.08 mg/mL level with an IC50 value of 0.099 mg/mL. Based on the results, the caper leaf EO emulsion has the potential to be proposed as a natural alternative to chemical preservatives in the food industry.

Remote sensing reveals fire-driven enhancement of a C4 invasive alien grass on a small Mediterranean volcanic island

Abstract. The severity and the extent of a large fire event that occurred on the small volcanic island of Stromboli (Aeolian archipelago, Italy) on 25–26 May 2022 were evaluated through remotely sensed data to assess the short-term effect of fire on local plant communities. For this purpose, the differenced normalized burned index (dNBR) was also used to quantify the extent of early-stage vegetation recovery dominated by Saccharum biflorum Forssk. (Poaceae), a rhizomatous C4 perennial grass of Paleotropical origin. The burned area was estimated to have an extension of 337.83 ha, corresponding to 27.7 % of the island surface and to 49.8 % of Stromboli's vegetated area. On the one hand, this event considerably damaged the native plant communities, hosting many species of high biogeographic interest. On the other hand, Saccharum biflorum clearly benefited from fire. In fact, this species showed a very high vegetative performance after burning, being able to exert unchallenged dominance in the early stages of the postfire succession. Our results confirm the complex and probably synergic impact of different human disturbances (repeated fires and the introduction of invasive alien plants) on the natural ecosystems of small volcanic islands.

Functional diversity and metabolic response in benthic communities along an ocean acidification gradient

Altered ocean chemistry caused by ocean acidification (OA) is expected to have negative repercussions at different levels of the ecological hierarchy, starting from the individual and scaling up to the community and ultimately to the ecosystem level. Understanding the effects of OA on benthic organisms is of primary importance given their relevant ecological role in maintaining marine ecosystem functioning. The use of functional traits represents an effective technique to investigate how species adapt to altered environmental conditions and can be used to predict changes in the resilience of communities faced with stresses associated with climate change. Artificial supports were deployed for 1-y along a natural pH gradient in the shallow hydrothermal systems of the Bottaro crater near Panarea (Aeolian Archipelago, southern Tyrrhenian Sea), to explore changes in functional traits and metabolic rates of benthic communities and the repercussions in terms of functional diversity. Changes in community composition due to OA were accompanied by modifications in functional diversity. Altered conditions led to higher oxygen consumption in the acidified site and the selection of species with the functional traits needed to withstand OA. Calcification rate and reproduction were found to be the traits most affected by pH variations. A reduction in a community's functional evenness could potentially reduce its resilience to further environmental or anthropogenic stressors. These findings highlight the ability of the ecosystem to respond to climate change and provide insights into the modifications that can be expected given the predicted future pCO2 scenarios. Understanding the impact of climate change on functional diversity and thus on community functioning and stability is crucial if we are to predict changes in ecosystem vulnerability, especially in a context where OA occurs in combination with other environmental changes and anthropogenic stressors.

Subspecies inflation hampers conservation efforts: a case study on wall lizards

Abstract The common practice of using subspecies as conservation targets raises the question of whether efforts are focused on preserving conspicuous components of the species’ phenotypic variability rather than evolutionarily significant units. To address this question, in this study we performed a comprehensive morphological and genetic assessment on all the subspecies of wall lizard described for the Aeolian Archipelago (Italy) to determine whether they represent distinct evolutionary lineages and/or discrete phenotypic partitions. Further, we applied a monophyly test to 70 subspecies belonging to seven wall lizard species occurring in Italy, based on our results and on previous phylogeographic studies. We found that none of the Aeolian subspecies represents a distinct evolutionary lineage, despite some morphological differentiation of island populations across the archipelago, suggesting a very recent origin of island populations and of the observed phenotype variation. Across seven wall lizard species, tests revealed that lizard subspecies rarely (< 9% of cases) match evolutionary units. This study demonstrates that intraspecific taxonomy of wall lizards is a poor predictor of phylogeographic partitions and evolutionary units, and therefore of limited use (if not dangerous) for defining conservation and management units. A better approach would be relying on the integration of genomic and phenotypic data to assess the evolutionary significance and conservation value of phenotypic and genetic units within species.

Marinitoga aeolica sp. nov., a novel thermophilic anaerobic heterotroph isolated from a shallow hydrothermal field of Panarea Island in the Aeolian archipelago, Italy.

A novel thermophilic strain, designated BP5-C20AT, was isolated from the shallow hydrothermal field of the Panarea island in the Aeolian archipelago close to Sicily, Italy. Cells are motile rods surrounded with a 'toga', Gram-stain-negative and display a straight to curved morphology during the exponential phase. Strain BP5-C20AT is thermophilic (optimum 55 °C), moderately acidophilic (optimum pH 5.6) and halotolerant (optimum 25 g l-1 NaCl). It can use yeast extract, peptone and tryptone. It uses the following carbohydrates: cellobiose, fructose, glucose, maltose, starch, sucrose and xylan. Elemental sulphur is used as an electron acceptor and reduced to hydrogen sulphide. The predominant cellular fatty acid is C16 : 0. Phylogenetic analysis showed that strain BP5-C20AT shared 97.3 % 16S rRNA gene sequence identity with the closest related species Marinitoga lauensis LG1T. The complete genome of strain BP5-C20AT is 2.44 Mb in size with a G+C content of 27.3 mol%. The dDDH and ANI values between the genomes of strains BP5-C20AT and M. lauensis LG1T are 31.0 and 85.70% respectively. Finally, from its physiological, metabolic and genomic characteristics, strain BP5-C20AT (=DSM 112332T=JCM 39183 T) is proposed as representative of a novel species of the genus Marinitoga named Marinitoga aeolica sp. nov. and belonging to the order Petrotogales, in the phylum Thermotogota.

Diversity of Fucales (Ochrophyta, Phaeophyceae) along the Coasts of Lipari and Vulcano (Aeolian Archipelago), Tyrrhenian Sea (Central Mediterranean Sea)

This study explored the biodiversity of Fucales along the islands of Lipari and Vulcano, almost ten years after the last studies on the phytobenthos of these islands. To carry out this research, a monitoring activity was conducted through both scuba dives and snorkelling activities. Through this study, a total of 13 species (four belonging to Cystoseira, three to Ericaria, two to Gongolaria, and four to Sargassum) was observed. When comparing the present data with past studies, nine species were previously reported, ten taxa were not found in the present study, and four taxa were reported here for the first time in the Aeolian Archipelago. The alpha (local) diversity was higher in Vulcano than in Lipari. Moreover, the beta (turnover) diversity showed a different assemblage in species grouping between the two islands. Since some of the observed species are currently considered rare or in regression, their finding in the Aeolian Archipelago is of particular interest. Therefore, they should receive special consideration, particularly in light of the possible future establishment of a marine protected area (MPA) in the Aeolian Archipelago.

Statistical Insights on the Eruptive Activity at Stromboli Volcano (Italy) Recorded from 1879 to 2023

Stromboli is an open-conduit active volcano located in the southern Tyrrhenian Sea and is the easternmost island of the Aeolian Archipelago. It is known as “the lighthouse of the Mediterranean” for its continuous and mild Strombolian-type explosive activity, occurring at the summit craters. Sometimes the volcano undergoes more intense explosions, called “major explosions” if they affect just the summit above 500 m a.s.l. or “paroxysms” if the whole island is threatened. Effusive eruptions are less frequent, normally occurring every 3–5 years, and may be accompanied or preceded by landslides, crater collapses and tsunamis. Given the small size of the island (maximum diameter of 5 km, NE–SW) and the consequent proximity of the inhabited areas to the active craters (maximum distance 2.5 km), it is of paramount importance to use all available information to forecast the volcano’s eruptive activity. The availability of a detailed record of the volcano’s eruptive activity spanning some centuries has prompted evaluations on its possible short-term evolution. The aim of this paper is to present some statistical insights on the eruptive activity at Stromboli using a catalogue dating back to 1879 and reviewed for the events during the last two decades. Our results confirm the recent trend of a significant increase in major explosions, small lava flows and summit crater collapses at the volcano, and might help monitoring research institutions and stakeholders to evaluate volcanic hazards from eruptive activity at this and possibly other open-vent active basaltic volcanoes.

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.

High resolution magnetic anomalies, volcanism and tectonics of the active “La Fossa” vulcanic system (Vulcano island) and Lipari island (South Italy)

In this paper we present the new high-resolution magnetic anomaly map of the La Fossa Caldera system and Lipari island (Southern Italy), obtained by merging two low-altitude aeromagnetic surveys. In these islands a variegated ensemble of magnetic anomalies develops in the north-south direction. The La Fossa Caldera is characterized by very high-intensity and short-wavelength magnetic anomalies, related to mafic intrusive/effusive sources, mainly aligned along the NNW-SSE and NS faults. Instead, the Lipari island is characterized by lower intensity anomalies related to sources with more evolved chemistry, elongated in the NE-SW, NNE-SSW and EW of the subordinate faults. Both the two sets of structures belong to the Tindari-Letojanni strike slip fault-system, a regional lineament along which the southern side of the Aeolian Archipelago is emplaced. The study identifies three distinctive magnetic zones on the Lipari island: the southern, the central, and the north-western ones. The southern zone is characterized by negative magnetic monopoles in correspondence with the younger rhyolitic domes and a Curie Isotherm upwelling. The central part of the island has an average lower intensity of positive anomalies, corresponding to the less evolved products of the intermediate Lipari volcanic epochs. The north-western side is characterized by higher intensity anomalies related to older volcanic epochs. The interplay among strike-slip tectonics, chemistry of the uprising magmas, and the thermal setting has contributed to the overall anomaly pattern in this sector of the Aeolian Archipelago. This interpretation is supported by the application of digital enhancement to the total intensity magnetic anomaly field and by the spatial correlation analysis of the magnetic and volcano-tectonic features. The obtained insights are useful to better understand the relationship between arc volcanism and tectonics. Moreover, they can also outline new inferences to forecast future eruptions of the active La Fossa volcanic system. In fact, recent unrest signals were registered at La Fossa Cone, which is one of the present-day active volcanoes of the Aeolian Archipelago, along with Stromboli island. Key pointsLa Fossa volcanic system of Vulcano and Lipari islands high resolution aeromagnetic surveys; Strike slip tectonics magnetic anomaly signature; Spatial correlation analysis of volcano-tectonic and magnetic features.

Garnet Xenoliths in Andesitic Lavas of Lipari: New Geochemical Data to Provide Additional Information on the Metamorphic Basement Under the Aeolian Arc

The purpose of this paper is to discuss and interpret a comprehensive set of geochemical (major and trace elements) data for xenolithic garnets included in high-K andesites from Lipari Island (Aeolian Archipelago, Italy), with the aim to constraint the parent rocks. Since, among all the mineral phases, garnet has a high affinity for the heavy REE (Dy-Lu) and HFSE (Hf, Zr, Ti), we use it as petrogenetic indicator. The investigated xenoliths are mainly composed of cordierite, garnet and Al-silicates and are considered as fragments of the metamorphic Calabria-Peloritani Orogen inferred to be the basement beneath the Aeolian volcanoes. Xenolithic garnet from Lipari andesites and metamorphic garnets from rocks of Southern Calabria and Peloritani Mountains were sampled and analysed. Major elements were determined through ESEM, whereas trace elements were acquired using LA-ICP-MS. Two types of garnets were recognised on the base of major elements, one homogeneous and one zoned, whit an almandine-dominant composition. The comparison between major and trace elements data of xenolithic and metamorphic garnets allowed defining nature of the basement beneath Lipari Island, which is composed of: a) a metamorphic Unit similar to the kinzigitic ones for the unzoned crystals; b) a metamorphic unit similar to the Aspromonte and not outcropping in Sicily and in Calabria for the zoned garnets.

A high-quality reference genome for the critically endangered Aeolian wall lizard, Podarcis raffonei.

The Aeolian wall lizard, Podarcis raffonei, is an endangered species endemic to the Aeolian archipelago, Italy, where it is present only in 3 tiny islets and a narrow promontory of a larger island. Because of the extremely limited area of occupancy, severe population fragmentation and observed decline, it has been classified as Critically Endangered by the International Union for the Conservation of Nature (IUCN). Using Pacific Biosciences (PacBio) High Fidelity (HiFi) long-read sequencing, Bionano optical mapping and Arima chromatin conformation capture sequencing (Hi-C), we produced a high-quality, chromosome-scale reference genome for the Aeolian wall lizard, including Z and W sexual chromosomes. The final assembly spans 1.51 Gb across 28 scaffolds with a contig N50 of 61.4 Mb, a scaffold N50 of 93.6 Mb, and a BUSCO completeness score of 97.3%. This genome constitutes a valuable resource for the species to guide potential conservation efforts and more generally for the squamate reptiles that are underrepresented in terms of available high-quality genomic resources.

Mollusk Response Under Ocean Acidification in Shallow Marine Settings of Sicily (Central Mediterranean)

Anthropogenic CO2 is a major driver of change in most marine ecosystems, as the consequent ocean acidification is threatening marine calcifying organisms. In this respect, long-term analyses on ocean acidification effects on marine ecosystems acclimated to high pCO2, as found around CO2 vents, are needed. Here we tackle mollusk assemblages from acidified shallow marine settings off the Aeolian archipelago (Central Mediterranean). The detected gradient manifests along a 34 m long transect (9.6 m and 11.4 m water depth), mostly in a Posidonia oceanica matte from normal (site 1) to high levels (site 3) of pCO2 (405 μatm, pH 8.1 and 715 μatm, pH 7.8; respectively). The strongest acidified condition at the vent crater (site 4, pCO2 1110 μatm, pH 7.7). At the vent site gaseous emissions are characterized by ~99% in volume of CO2 and ~0.6% of H2S. However, water dissolved H2S was below detection limit and the sulphate content along the transect does not show significant variations with respect to normal seawater values. Preliminary paleoecologic surveys on diversity structure (diversity profiles) and taphonomic degradation (NMDS, z scored % values) were conducted on mollusk remains collected along the natural pH gradient (sites 1-4). Along the P. oceanica matte (sites 1-3), overall mollusk taxon diversity (alpha and beta) decreased, mollusk in site 3 were mostly juveniles and had higher overall taphonomic damages than those retrieved at normal pH conditions. Within the vent crater only fewer and highly taphonomically altered gastropod specimens were retrieved on the pebbly seafloor, suggesting a very short residence time of shell material and rapid dissolution. Even if vents are not exact predictors of the anthropogenic-designed future of marine settings, due to their limited spatial and temporal extent, they can act as natural laboratories where to evaluate the output of ecosystem processes under rising pCO2 and the effects on the creation of the future fossil record.

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.

Ephedra strongylensis (Ephedraceae), a new species from Aeolian islands (Sicily)

Ephedra strongylensis, a new species from the islands of Stromboli and Strombolicchio (Aeolian Archipelago, Sicily), is described and illustrated. It is morphologically well differentiated from the other species occurring in the Mediterranean territories, showing some relationships especially with Ephedra aurea, chiefly for the articles scabrous-wrinkled and not fragile at the nodes. However, significant features distinguish the new species from the latter, chiefly regarding the size and shape of twigs, leaves, male and female cones, ovules, seeds, fruiting strobili and pollen grains. Its ecology, conservation status and taxonomic considerations with other allied Mediterranean species are provided too.

Posidonia bonsai: Dwarf Posidonia oceanica shoots associated to hydrothemal vent systems (Panarea Island, Italy)

Very small-sized shoots of the Mediterranean seagrass Posidonia oceanica, defined as “bonsai” shoots, were found in areas with most intense CO2 emissions and low pH associated with four vents systems off Panarea island (Aeolian Archipelago, Sicily, Southern Tyrrhenian Sea). Bonsai shoots were sampled in September 2021 and October 2022: Bottaro crater (8 m depth), Camp 7 (16 m and 21 m), Black Point (20 m) and Hot/Cold Points (10 m). They had 2–6 leaves, and adult-intermediate leaves were 5–21 cm long and 3.5–7 mm wide, with leaf shoot surface ranging 4.8 and 44.5 cm2, and shoot leaf biomass between 16 and 89 mg (d.w.). These values were all significantly lower (t-test p < 0.006–0.0001) than those measured in normal-sized shoots collected within the vents and in control sites not affected by gas emissions. Bonsai shoots had 86–89% lower leaf surface, and 61–75% lower leaf biomass than all normal-sized shoots measured. The sheath thickness of the bonsai shoots was very low (0.1–0.8 mm), and the temporal trend of sheath thickness along the rhizome (lepidochronology) showed an irregular pattern, without the clear cyclical seasonal variation typical of normal-sized shoots. The reasons of size reduction and lack of temporal cycle in lepidochronology are discussed in the light of plant acclimatization and the constraints imposed by the continuous exposure to the stressful conditions of seawater acidification and presence of phytotoxic gases (e.g. hydrogen sulfide) in the vents.

Modelling Erosion and Floods in Volcanic Environment: The Case Study of the Island of Vulcano (Aeolian Archipelago, Italy)

The re-mobilization of volcaniclastic material poses a hazard factor which, although it decreases with time since the last eruption, remains present in the hydrographic basins of volcanic areas. Herein, we present the results of the numerical modelling of erosive phenomena of volcanic deposits, as well as of flooding in the volcanic area. The proposed approach includes runoff estimation, land use analysis, and the application of hydraulic and erosion modelling. It exploits the Iber software, a widely used and validated model for rainfall-runoff, river flooding, and erosion and sediment transport modelling. The methodology was applied to the Island of Vulcano (Italy), known for the erosion phenomena that affect the slopes of one of its volcanic cones (La Fossa cone). The rainfall excess was calculated using a 19-year dataset of hourly precipitations, and the curve number expressed by the information on soil cover in the area, derived from the land cover and land use analysis. The erosion and flow models were performed considering different rainfall scenarios. Results show a particularly strong erosion, with thicknesses greater than 0.4 m. This is consistent with field observations, in particular with some detailed data collected both after intense events and by long-term observation. Results of the hydraulic simulations show that moderate and torrential rainfall scenarios can lead to flood levels between 0.2 and 0.6 m, which mostly affect the harbours located in the island’s inhabited area.

Condition- and context-dependent variation of sexual dimorphism across lizard populations at different spatial scales

The evolution of sexual dimorphism (SD) is driven by intricate interplays between sexual and natural selection. When it comes to SD variation within populations, however, environmental factors play a major role. Sexually selected traits are expected to be strongly dependent on individual body condition, which is influenced by the local environment that individuals experience. As a consequence, the degree of SD may also depend on resource availability. Here, we investigated the potential drivers of SD expression at two sexually dimorphic morphometric traits, body size (snout vent length) and head shape (head geometric morphometrics), in the Italian wall lizard (Podarcis siculus). We assessed the existence of condition- and context-dependent SD across ten islands of the Aeolian archipelago (southern Italy), at within- and among-population scales. We observed strong geographical variation of SD among islands, and tested three potential SD predictors related to resource availability (individual body condition, ecosystem productivity, temperature). Body condition and ecosystem productivity were the main drivers of body size SD variation, and body condition was also the main driver for head shape SD. Our results highlight that the expression of SD in the Italian wall lizard is both condition- and context-dependent. These results are congruent at within- and among-populations scales highlighting that spatial multi-scale analysis represents a useful approach to understand patterns of SD expression.

A Statistical Approach to Satellite Time Series Analysis to Detect Changes in Thermal Activities: The Vulcano Island 2021 Crisis

Vulcano belongs to the seven volcanic islands forming the Aeolian archipelago (Italy) and has the privilege to define an eruptive style as “Vulcanian”. It has to be considered as an active volcano as its most recent activity demonstrated. Starting by late spring 2021, the thermal state of the Vulcano summit area changed and the gas emission increased. During the summer and, in particular, starting from September, geophysical and geochemical signals, precisely those linked to the activity of the hydrothermal system that feeds the fumaroles of the Fossa crater, varied. The temperature of the gases emitted by the fumaroles on the crater rim has increased and the composition of the gases has showed an increase in CO2 and SO2 (carbon dioxide and sulfur dioxide) concentration. For such reasons, the authors decided to follow this event by analyzing the remotely sensed available data suitable for detecting changes in thermal state. By processing the TIRS (Landsat 8) and ASTER time series, two long-term surface temperature logs were obtained and, therefore, by adopting a statistical approach, an analysis in both space and time domains has emphasized a thermal signature since mid-September 2021.