http://hdl.handle.net/2122/184 Mon, 20 May 2013 22:42:26 GMT 2013-05-20T22:42:26Z http://hdl.handle.net/2122/8680 Title: The importance of methanotrophic activity in geothermal soils of Pantelleria island (Italy) Authors: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Gagliano, A.L.; Università di Palermo, Dipartimento DiSTeM; Quatrini, P.; Università di Palermo, Dipartimento STEBICEF; Parello, F.; Università di Palermo, Dipartimento DiSTeM Abstract: Methane is a major contributor to the greenhouse effect, its atmospheric concentration being more than doubled since the XIX century. Every year 22 Tg of methane are released to the atmosphere from several natural and anthropogenic sources. Natural sources include geothermal/volcanic areas but the estimation of the total methane emission from these areas is currently not well defined since the balance between emission through degassing and microbial oxidation within the soils is not well known. Microbial oxidation in soils contributes globally for about 3-9% to the removal of methane from the atmosphere and recent studies evidenced methanotrophic activity also in soils of volcanic/geothermal areas despite their harsh environmental conditions (high temperatures, low pH and high concentrations of H2S and NH3). Methanotrophs are a diverse group of bacteria that are able to metabolize methane as their only source of carbon and energy and are found within the Alpha and Gamma classes of Proteobacteria and within the phylum Verrucomicrobia. Our purpose was to study the interaction between methanotrophic communities and the methane emitted from the geothermally most active site of Pantelleria island (Italy), Favara Grande, whose total methane emission has been previously estimated in about 2.5 t/a. Laboratory incubation experiments with soil samples from Favara Grande showed methane consumption values of up to 9500 ng g-1 dry soil per hour while soils collected outside the geothermal area consume less than 6 ng g-1 h-1. The maximum consumption was measured in the shallowest part of the soil profile (1-3 cm) and high values (>100 ng g-1 h-1) were maintained up to a depht of 15 cm. Furthermore, the highest consumption was measured at 37 C, and a still recognizable consumption (>20 ng g-1 h-1) at 80 C, with positive correlation with the methane concentration in the incubation atmosphere. These results can be considered a clear evidence of the presence of methanotrophs that were investigated by culturing and culture-independent techniques. The diversity of proteobacterial methanotrophs was investigated by creating a clone library of the amplified methane mono-oxygenase encoding gene, pmoA. Clone sequencing indicates the presence of Gammaproteobacteria in the soils of Favara Grande. Enrichment cultures, on a mineral medium in a CH4-enriched atmosphere, led to the isolation of different strains that were identified as Methylocistis spp., which belong to the Alphaproteobacteria. The presence of Verrucomicrobia was detected by amplification of pmoA gene using newly designed primers. Soils from Favara Grande show therefore the largest spectrum of methanotrophic microorganisms until now detected in a geothermal environment. While the presence of Verrucomicrobia in geothermal soils was predictable due to their thermophilic and acidophilic character, the presence of both Alpha and Gamma proteobacteria was unexpected. Their presence is limited to the shallowest part of the soil were temperatures are lower and is probably favored by a soil pH that is not too low (pH 5) and their contribution to biological methane oxidation at Pantelleria is significant. Understanding the ecology of methanotrophy in geothermal sites will increase our knowledge of the role of soils in methane emissions in such environments. Sun, 07 Apr 2013 22:00:00 GMT http://hdl.handle.net/2122/8680 2013-04-07T22:00:00Z http://hdl.handle.net/2122/8679 Title: The fluids’ geochemistry along the "Sperchios Basin - Northern Evoikos Gulf" Graben, a geodynamically complex area of Central Greece Authors: D'Alessandro, W.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Bellomo, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Brusca, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Calabrese, S.; Università di Palermo, Dipartimento DiSTeM; Kyriakopoulos, K.; University of Athens, Dept. Geology and Geoenvironment, Greece Abstract: The study area is a 130 km long fast spreading graben in Central Greece. Its complex geodynamical setting includes both the presence at depth of a subduction slab responsible for the recent (Quaternary) volcanic activity in the area and the western termination of a tectonic lineament of regional importance (the North-Anatolian fault). Its high geothermal gradient is evidenced by the presence of many thermal springs with temperatures from 19 to 82 C, issuing along the normal faults bordering the graben. In the period 2004-2012 about 50 gas and water samples have been collected and their chemical and isotopic analysis revealed a wide range of compositions. Going from west to east the gas composition changes from CH4- to CO2-dominated passing through mixed N2- CH4 and N2-CO2 compositions, while at the same time the He isotopic composition goes from typical crustal values (0.05 R/Ra) up to 0.87 R/Ra (corrected for air contamination), showing in the easternmost sites a small but significant mantle input. Isotopic composition of CH4-C indicates a thermogenic origin for the CH4-rich samples and hydrothermal origin for the remaining samples. Positive 15N values indicate a contribution of crustal derived nitrogen for the N2-rich samples. The 13C values of most the CO2-enriched samples show a mixed origin (mantle and marine carbonates). Also the chemical composition of the waters shows differences along the graben and two main groups can be separated. The first, represented by dilute waters (E.C. < 600 S/cm), is found in the westernmost sites characterised by the presence of CH4-rich and mixed N2-CH4 gases. The remaining waters display higher salinities (E.C. from 12 to 56 mS/cm) due to the mixing with a modified marine component. Only the water composition of easternmost sites in the Giggenbach’s cation triangular graph plots in the field of the partially equilibrated waters giving estimated temperatures at depth of 150-160 C. Sun, 07 Apr 2013 22:00:00 GMT http://hdl.handle.net/2122/8679 2013-04-07T22:00:00Z http://hdl.handle.net/2122/8416 Title: Discrimination between effects induced by microbial activity and water-rock interactions under hydrothermal conditions according to REE behaviour Authors: Censi, P.; DiSTeM UniPA; Cangemi, M.; DiSTeM UniPA; Madonia, P.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Saiano, F.; AGROPa UniPA; Brusca, L.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Zuddas, P.; iSTeP Universitè P. er M. Curie Paris Abstract: Rare Earths (REE) were investigated in siliceous stromatolites forming in the Specchio di Venere Lake in Pantelleria Island. Chondrite-normalised patterns show significant La enrichments and Eu depletions suggesting that fluids involved in stromatolite growth experienced strong rock-water interactions under hydrothermal conditions. At the same time, enrichments of heavy REE (HREE), with respect to intermediate REE (MREE) suggest that hydrothermal fluids interacted with microbial mats during deposition of stromatolites. The above-mentioned features suggest that rock-water interactions and bacterial activity were simultaneously recorded in REE patterns of stromatolites and can be discriminated in terms of amplitudes of La anomaly and HREE/MREE ratio Sat, 08 Jun 2013 22:00:00 GMT http://hdl.handle.net/2122/8416 2013-06-08T22:00:00Z http://hdl.handle.net/2122/8263 Title: Temporal trends and matrix-dependent behaviors of trace elements closed to a geothermal hot-spot source (Aeolian Archipelago, Italy) Authors: Renzi, M.; Research Centre in Lagoon ecology, fishery and aquaculture (Ecolab) Polo Universitario Grossetano, University of Siena,; Romeo, T.; ISPRA – Higher Institute for Environmental Protection and Research, STS Palermo; Guerranti, C.; Department of Environmental Science, University of Siena,; Perra, G.; Department of Environmental Science, University of Siena,; Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Focardi, S. E.; Department of Environmental Science, University of Siena,; Esposito, V.; ISPRA – Higher Institute for Environmental Protection and Research, STS Palermo; Andaloro, F.; ISPRA – Higher Institute for Environmental Protection and Research, STS Palermo Abstract: Degassing activity from marine shallow-water hydrothermal vents represents a natural important source of trace elements of particular ecotoxicological concern, such as Hg, Cd, Pb, and As. In 2002, on November 3rd, a submarine area of the Aeolian Archipelago (Italy) was affected by an exceptional hydrothermal activity, presumably associated to a significant trace element release. This study developed in the highest impacted area, was focused on different environmental matrices (water, sediment, primary producers, and fishes) with the aim to evaluate on a statistical basis temporal dynamics involving trace elements closed to the emission source. Results evidenced that this event produced significant changes in water column, modifying the general assessment of the chemical descriptors selected (Na, K, Mg, Ca, Cl, Br, SO4 2-, HCO3 -). Furthermore, the degassing activity represents a significant input of Hg, Cd, Pb, and As for all of the sampled matrices, being it responsible of the higher levels observed in the study area compared to controls. Concentrations measured in sediments and biota (Cystoseira compressa, Serranus cabrilla) at temporal intervals of ten months distanced, supported the occurrence of different time scale dynamics which are both element and matrix-dependent. In particular, levels of Cd and As measured in liver tissues of S. cabrilla evidenced a significant trend to increase with the time, allowing to exclude a quick recovery of the study area. Measured values in edible fishes tissues are, also, notably higher than risk limits proposed by the 2001/22/CE Directive for human consumption, so, local-based caught have to be accurately regulated to avoid the occurrence of diet over-exposure. Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/8263 2010-12-31T23:00:00Z http://hdl.handle.net/2122/8262 Title: Detection of fresh and thermal waters over an island with extinct volcanism: the island of Salina (Aeolian arc, Italy) Authors: Italiano, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Caruso, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia Abstract: A geochemical prospection of the fluids circulating over a volcanic island highlighted the existence of reservoirs of both fresh and thermal water although only a few natural manifestation, mainly occurring in submarine environment, provide clues of their existence. Coupling the information provided by the diffuse gas bubbling and the low-salinity waters discharged from the sea floor off the Island with those from the low-salinity and thermal waters collected from in-land wells drilled in recent times we found that a large amount of fresh and thermal waters are continuously discharged at the sea level. The thermal waters, collected at a temperature of 32-36°C, show a typical marine recharge with equilibrium temperatures estimated to be in the range of 120-160°C. As matter of fact, the small island holds relatively large reservoirs of both fresh and thermal waters. The geochemical features of the circulating fluids are driven by water-rock and gas-water interaction processes, while the heat supplied to the geothermal reservoir comes from volcanic rocks that are still cooling down after the end of the last volcanic activity supposed to be not older than 13ky. Fri, 31 Dec 2010 23:00:00 GMT http://hdl.handle.net/2122/8262 2010-12-31T23:00:00Z http://hdl.handle.net/2122/7472 Title: Geochemistry of groundwater from Graciosa Island (Azores): A contribution to the hydrothermal system conceptual model Authors: Carvalho, M.R.; 1Universidade de Lisboa, Faculdade de Ciencias, Depart. Geologia/CeGUL, Portugal; Carreira, P.; Instituto Tecnologico e Nuclear, Lisboa, Portugal; Marques, J.M.; Instituto Superior Tecnico, Lisboa, Portugal; Capasso, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Grassa, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Nunes, J.C.; Universidade dos Açores & INOVA Inst., Azores, Portugal Abstract: Graciosa island is located in the Azores Archipelago, along the so-called Terceira Rift, a major tectonic structure that makes the NE boundary of the Azores Plateau. In general terms, it includes a basaltic plataform on the NW and a silicic poligenetic volcano with caldera on the SE, the Graciosa Caldera Volcano. This volcano has produced significant tephra falls, pyroclastic flows, lahars, and lava flows, both of basaltic s.l. and trachitic s.l. composition. The hydrothermal system shows fumarolic emissions inside the volcano caldera and thermal springs located along the shoreline. This system is exploitated in a thermal building through shallow and deep (110 m) boreholes, near the coast. In Graciosa two types of Na-Cl groundwater systems can be identified: 1) a cold one emerging at springs and exploited by wells for public water supply, and 2) a hydrothermal system with temperatures around 40-44 °C. The cold groundwaters have pH higher than 7 and different degree of mineralization, according to the proximity to the sea. The thermal waters show mixing with seawater, pH varying between 6.20 and 6.94, 166 mg/L of SiO2, and significant concentration of metals, such as Mn, Fe, Co, Ni, Cu and Zn. The thermal water mineralization varies strongly, showing EC from 8.87 mS/cm (shallow water) to 47.4 mS/cm (deeper water). The higher mineralized water is rich in CO2(g), with 2130 mg/L of total dissolved CO2. Geothermometers application reveals aquifer temperature around 167 °C and immature/mixed waters, not reaching complete equilibrium with reservoir rock. The geochemistry of the thermal waters indicates the occurrence of seawater/host rock interaction processes at high temperature and slightly acid conditions, favored by CO2(g) input, and a different degrees of mixing with cold and shallow groundwaters. Sat, 13 Aug 2011 22:00:00 GMT http://hdl.handle.net/2122/7472 2011-08-13T22:00:00Z http://hdl.handle.net/2122/7467 Title: Stable isotope feature of groundwaters from Graciosa volcanic Island (Azores) – preliminary results Authors: Carreira, P.; Instituto Tecnológico e Nuclear, Sacavém, Portugal; Marques, J.M.; Instituto Superior Técnico, Lisboa, Portugal; Carvalho, M.R.; Faculdade de Ciencias de Lisboa, Lisboa, Portugal; Capasso, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Grassa, F.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione Palermo, Palermo, Italia; Nunes, D.; Instituto Tecnológico e Nuclear, Sacavém, Portugal; Nunes, J.C.; Universidade dos Açores & INOVA Institute, S. Miguel, Azores, Portugal Editors: Demény, Attila; Instute for geochemical research, Hungarian Academy of Sciences Abstract: The Azores archipelago is made of nine islands all of volcanic origin and a few islets located in the North Atlantic Ocean, about 1800 km west of Portuguese mainland at the triple junction of the Eurasian, North American and Nubian plates (Azores Triple Junction = ATJ). Graciosa Island is part of the Central Group of Azores archipelago and is located on the Terceira Rift, a major tectonic feature of the ATJ. The main hydrothermal manifestations at Graciosa Island occur in the Caldeira volcano (SE part of the island), and particularly inside the huge (150 m wide, 80 m high) Furna do Enxofre lava cave located in the Caldeira, where a bubbling mud pool releases steam and gases, leading to the accumulation of CO2 at the bottom of the cave, filled by a coldwater subterranean lake. Three field work campaigns were carried out at Graciosa Island and 14 water samples have been collected, from boreholes, springs and the subterranean lake for isotopic (18O, 2H and 3H) and chemical analysis. The groundwater samples were plotted along the GMWL, and two water groups were identified in the 18O vs. 2H diagram. The splitting up of the samples is even more visible when the O-18 content is plotted as a function of the temperature or as a function of the electrical conductivity. Besides the differences in mineralization and temperature observed in the groundwater samples from Graciosa Island, an isotopic shift towards more enriched values is also observed. The salinity and isotopic content seems to indicate not a simple mixture between two end-members, i.e. seawater – fresh water: another process of mineralization and isotope enrichment must be considered in this active volcanic environment. A hypothesis to be formulated is that the source of salts could be associated to mixing with boiling seawater, that by evaporation will be able to: i) increase groundwater salinity, ii) strongly change the 2H content to more enriched values, and iii) absent or limited variation in d18O content. Wed, 03 Aug 2011 22:00:00 GMT http://hdl.handle.net/2122/7467 2011-08-03T22:00:00Z http://hdl.handle.net/2122/7422 Title: Secondary hydrothermal minerals in buried rocks at the campi flegrei caldera, Italy: a possible tool to understand the rock-physics and to assess the state of the volcanic system Authors: Mormone, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Tramelli, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Di Vito, M. A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Piochi, M.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Troise, C.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; De Natale, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: The distribution of the alteration assemblages and the related physico-chemical changes induced in the rocks with depth, may provide useful information on the state of the system. Drillholes are the only way to define hydrothermal alteration depth-profiles in variable geological contexts. Deep drillings exploiting programs were conducted since the 1970’s by the Agip-Enel Joint Venture in the Quaternary Campi Flegrei caldera (southern Italy), where a geothermal system has been active since at least historical times. New macroscopic and microscopic investigations were performed on selected samples made available by Agip in order to: 1) define the precursor lithology, 2) describe the relationships among texture, mineralogy and depth of the studied core samples and 3) examine the character of the secondary minerals and their distribution with depth and temperature. The new data are integrated with physical properties and elastic parameters of cored rocks, as well as structural information and field data, all available from the physical, seismological, geodetical and volcanological literature. The depth-related multi-parameters profiles provide evidence on the different behavior of the buried rocks beneath the Licola 1, Mofete and San Vito 1 areas, sited in three structurally different sectors of the caldera. The features of the hydrothermally altered rocks are a key to interpret the heterogeneities of the Campi Flegrei substratum, as deduced by velocity, attenuation and scattering P- and S- waves tomography. The time and space distribution of both the eruptive vents and the extruded magma volumes are consistent with the results of our analysis. Therefore, we interpret the observed Campi Flegrei geothermal system as a response to the distribution of volcanic activity in two structurally distinct sectors of the caldera. The central-eastern sector, where the San Vito 1 well was drilled, represents the preferential pathways for both gas escape and magma ascent at least since 8 kyrs, in contrast with the other sites of the caldera where eruptions occurred with minor frequency and magnitude. Mon, 12 Dec 2011 23:00:00 GMT http://hdl.handle.net/2122/7422 2011-12-12T23:00:00Z http://hdl.handle.net/2122/7270 Title: The Geothermal Potential Of Campania Volcanoes Authors: Carlino, S; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Somma, R; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Troise, C; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; De Natale, G; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: x Wed, 31 Aug 2011 22:00:00 GMT http://hdl.handle.net/2122/7270 2011-08-31T22:00:00Z http://hdl.handle.net/2122/7269 Title: THE CAMPI FLEGREI DRILLING PROJECT "CFDDP": UNDERSTANDING THE MAGMA-WATER INTERACTION AT LARGE COLLAPSE CALDERAS Authors: De Natale, G; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Troise, C; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Troiano, a; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Di Giuseppe, M.G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Sangianantoni, A; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Vertechi, E; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Carlino, S; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Somma, R; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; Petrillo, Z; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia Abstract: x Mon, 31 Oct 2011 23:00:00 GMT http://hdl.handle.net/2122/7269 2011-10-31T23:00:00Z