La distribuzione areale della vegetazione come indicatore

I vulcani a condotto chiuso, tra i quali si annoverano il Complesso Somma-Vesuvio in Campania e il cratere de “La Fossa” nell’Isola di Vulcano (Eolie, ME), sono spesso caratterizzati da attività fumarolica per lo più concentrata nelle aree intra-e peri-crateriche. Il componente principale dei fluidi fumarolici è il vapore acqueo, che spesso è associato a composti acidi (HCl, HF, H2S) in proporzioni variabili e dipendenti dallo stato di attività del vulcano. Anche le temperature delle emissioni variano considerevolmente, con estremi che vanno alla condensazione dell’acqua nel suolo a poche decine di °C sino all’emissione in atmosfera di vapore surriscaldato a diverse centinaia di °C. Le differenti composizioni chimiche e temperature delle aree esalanti possono quindi influenzare la distribuzione areale della vegetazione. L’esistenza di una relazione tra lo stato di salute e/o la presenza di vegetazione in aree vulcaniche italiane sembra confermata da osservazioni preliminari condotte sul M. Vesuvio e nell’Isola di Vulcano. In quest’ultima si sono osservate variazioni significative nel corso di un episodio di incremento dell’attività (unrest vulcanico) che ha avuto inizio nel Novembre 2004 ed è tutore in corso. La identificazione di markers vegetali dell’attività esalativa, e la loro mappatura dinamica nel tempo, potrebbero quindi fornire informazioni utili a definire lo stato di attività di un vulcano a condotto chiuso

Monitoring climatic changes and carbon cycle in canyons and caves: the C6 project.

The acronym C6 means "Climatic Changes and Carbon Cycle in Canyons and Caves". It is a monitoring project, for the evaluation of climate change signals, based on measuring sites located inside canyons and caves; it merged in the year 2005, under the scientific supervision of the Palermo Branch of the Italian National Institute for Geophysics and Volcanology (I.N.G.V.), two different monitoring programs active since 1999. The choice of these environments is based on their morphological structure: being them more or less segregated respect the outer atmosphere, they act as low-pass filters respect the variations of the monitored parameters, which are rainfall and dropping water amounts and rates, air temperatures and relative humidity and carbon dioxide concentrations in the atmosphere. On the basis of the preliminary data, reported and discussed in the paper, the C6 network seems to be capable to give useful information on the local effects of global changes, even if at the moment the monitored parameters concern only the abiotic components of the studied ecosystems

Il programma di monitoraggio C6: Climatic Changes and Carbon Cycle in Canyons and Caves

L'acronimo C6 sta per "Climatic Changes and Carbon Cycle in Canyons and Caves". E' un progetto di monitoraggio dei parametri climatici e dell'anidride carbonica, nato come tale nel 2005, ma che ha raggruppato al proprio interno attività di monitoraggio ambientale promosse da gestori di aree protette ed associazioni sportivo-ambientali sin dal 1999. Allo stato attuale sono attivi 6 siti di misura, disposti lungo un transetto Sud-Nord nell'areale mediterraneo, dalla Giordania sino all’Appennino Settentrionale. Un settimo sito sarà attivato entro l'estate 2006 in una cavità carsica in prossimità di Sarajevo (Bosnia Herzegovina). Il progetto si propone di monitorare parametri climatici ed ambientali all'interno di gole e grotte, con particolare riferimento alle concentrazioni di anidride carbonica in atmosfera, a temperatura ed umidità atmosferiche ed alle intensità di pioggia e stillicidio.Il progetto C6 assume rilevanza ai fini della conservazione della biodiversità in quanto le gole, specialmente in ambienti aridi e semi-aridi, rappresentano spesso l'unico luogo della superficie dove è presente acqua, costituendo quindi un rifugio preferenziale per tutte quelle specie viventi per le quali la disponibilità costante di acqua è fondamentale per il proprio ciclo vitale. Attraverso la rete C6 ci si propone di valutare la criticità dei parametri monitorati ai fini della conservazione degli ecosistemi presenti ed i possibili effetti derivanti da processi di cambiamento climatic

Mud volcanoes in onshore Sicily: a short overview

A short overview on Sicilian mud volcanoes is given. A total of 8 sites are presently known and studied in Sicily, mainly located in central–southern Sicily (Caltanissetta basin). All of these are of small dimension and sometimes associated to water pools. Methane is the main emitted gaseous phase, with the exception of the Paternò site, dominated by CO2 due to its proximity to Mt. Etna. Emitted waters are of the chloride–sulphate–alkaline type, due to the dominance of NaCl as the main dissolved salt. Sicilian mud volcanoes represent a potential threat for humans but, at the same time, they are threatened by anthropic activities. The main risks are related to the damages produced by paroxysmal events, while their survival is threatened by illegal discharge of wastes, consumption of rural land and agricultural activities

Aquatic Macrophytes Occurrence in Mediterranean Farm Ponds: Preliminary Investigations in North-Western Sicily (Italy)

Mediterranean wetlands are severely affected by habitat degradation and related loss of biodiversity. In this scenario, the wide number of artificial farm ponds can play a significant role in the biodiversity conservation of aquatic flora. In the present contribution we show the preliminary results of a study on Mediterranean farm ponds of north-western Sicily (Italy), aimed to investigating the environmental factors linked to the occurrence of submerged macrophytes (vascular plants and charophytes). We studied the aquatic flora of 30 ponds and determined the chemical and isotopic composition of their water bodies on a subset of the most representative 10 sites. Results show that (1) farm ponds host few but interesting species, such as Potamogeton pusillus considered threatened at regional level; (2) Chara vulgaris, C. globularis and P. pusillus behave as disturbance-tolerant species, occurring both in nitrates-poor and nitrates-rich waters, whereas Stuckenia pectinata and Zannichellia palustris occur only in nitrates-poor waters. Although farm ponds are artificial and relatively poor habitats, these environments seem to be important for the aquatic flora and for the conservation of the local biodiversity, and can give useful information for the use of macrophytes as ioindicators in the Mediterranean area

Le fumarole vulcaniche

Il magma che alimenta i vulcani, oltre ad essere costituito da roccia fusa, è anche ricco di fluidi, tra i quali i più abbondanti sono l’acqua (H2O), l’anidride carbonica (CO2), i composti dello zolfo come l’anidride solforosa (SO2) e l’idrogeno solforato (H2S) ed infine, in concentrazioni minori, anche gli acidi fluoridrico (HF) e cloridrico (HCl)

Decoupling of ground level pressures observed in Italian volcanoes: are they driven by space weather geo-effectiveness?

Investigations on correlation drops between near-ground atmospheric pressures measured at sea level and at higher altitudes on Italian volcanoes have been carried out. We looked for perturbations of the atmospheric pressure field driven by volcanic activity, but not excluding possible external triggers for the observed anomalies. Decorrelations between atmospheric pressures measured at Stromboli Island in stations located at different altitudes (years 2002-10) have been analysed and compared with data from other volcanic (Vesuvius) and non volcanic (Mt. Soro) orographic structures. We investigated as their possible triggers volcanic, meteorological and space weather parameters, with particular attention to Total Solar Irradiance (TSI), Kp index and Forbush decreases. Pressure decorrelations seems to be driven by astronomic cycles, with maxima in summer and minima in winter. A further contribution was found, seemingly assignable to TSI anomalies, with correlation minima occurring 12 hours after these but only during phases of high Sun activity. Moreover, during the same phases a main periodicity of about 27 days in pressure decorrelations was revealed by FFT analysis. This period is the same of the Sun Carrington rotation, expressing the periodic reappearance of sunspot groups on Sun’s surface. The strong similarity between recurrences of sunspot number and atmospheric pressure anomalies further supports the role of the former as a possible trigger for the latter

Possible Micrometeorological Anomalies Induced by Volcanic Activity Recorded at Stromboli Island (Aeolian Archipelago, Italy)

Hourly values of atmospheric pressure and air temperature have been acquired at the top of two volcanic islands, Stromboli and Salina in the Aeolian Archipelago (Italy), very similar in height and morphology but completely different with regard to their volcanic activity state: the former is permanently active, whereas the latter is extinguished. During the last four years Stromboli experienced normal activity, volcanic unrests, and an effusive eruption (August–November 2014).The comparative analysis of the recorded data, both in the time and frequency domains, evidenced a peculiar micrometeorological regime at Stromboli, more turbulent during unrests with respect to the quieter periods, but showing an apparent paradox during eruptions, characterized by a lower atmospheric turbulence. These observations suggest that the studied volcanic-micrometeorological system is chaotic, due to contemporary opposite transients generated in the atmosphere by volcanic activity changes, and that micrometeorological conditions in volcanic areas are controlled both by exogenous processes and volcanic activity

Georeferenced cartography dataset of the La Fossa crater fumarolic field at Vulcano Island (Aeolian Archipelago, Italy): conversion and comparison of data from local to global positioning methods

The present study illustrates the procedures applied for the coordinate system conversion of the historical fumarole positions at La Fossa crater, to allow their comparison with newly acquired global positioning system (GPS) data. Due to the absence of ground control points in the field and on both the old Gauss Boaga and the new UTM WGS 1984 maps, we had to model the transformation errors between the two systems using differential GPS techniques. Once corrected, the maps show a residual Easting shifting, due to erroneous georeferencing of the original base maps; this is corrected by morphological comparative methods. The good correspondence between the corrected positions of the historical data and the results of the new GPS survey that was carried out in 2009 highlights the good quality of the old surveys, although they were carried out without the use of accurate topographical instruments

The use of non-invasive field techniques in the study of small topographically closed lakes: two case studies in Sicily (Italy)

Small endhoreic (topografically closed) lakes represent a little percentage of continental waters but, in arid or sub-arid regions, they develop special ecosystems potentially prone to ecological involution due to climatic changes. The mandatory use of light, non-invasive field techniques is often required, especially in protected areas. In the present work the use of non-invasive techniques like GPS−based bathymetric and photographic surveys have been applied to the study of two lakes, Specchio di Venere and Sfondato (Sicily, southern Italy), both natural reserves. The comparison between historical surveys and modern GPS−based bathymetries highlighted the difficulty of using the former for the reconstruction of climatic-induced variations due to the low number of measurements (spatial aliasing). In particular, at the intracaldera Lake Specchio di Venere, a high resolution survey gave new insights into a peculiar geo-ecosystem whose evolution is driven by both volcanic phenomena and biomineralization processes. On the contrary, the morphology of Lake Sfondato floor is much more simple and driven only by the superimposition of a detrital sedimentation on the initial collapse that generated the lake. The comparison betweem direct measurements and estimated changes of lake level, carried out between February 2008 and October 2009 variations, allowed us to test different hypotheses of hydrological balances, leading to opposite conclusions with respect to previous studies and remarking the fundamental importance of direct measurements in the validation of theoretical hydrological models