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Pizzino, L.; Galli, Gianfranco; Mancini, C.; Quattrocchi, F.; Scarlato, Piergiorgio

doi:10.1023/a:1020398128649

Cited by 46 publications

(8 citation statements)

References 35 publications

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“…However, the Tor Caldara gas is more enriched in H 2 S as compared to other shallow-water vent sites. This could be attributed to the fact that, unlike other shallow-water vent sites, the temperature at Tor Caldara is not affected by geothermal processes and H 2 S is a product of low temperature hydrothermal activity in the perivolcanic outgassing areas (Pizzino et al, 2002; Boatta et al, 2013). Salinity of the Mediterranean is known to be high (between 36 ppt near Gibraltar to 39 ppt in the eastern basin) because the evaporation processes are more dominant than fresh water input from precipitation and river discharge (Kallel et al, 1997).…”

Section: Discussionmentioning

confidence: 99%

Ecological Succession of Sulfur-Oxidizing Epsilon- and Gammaproteobacteria During Colonization of a Shallow-Water Gas Vent

et al. 2018

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In this study, we integrated geochemical measurements, microbial diversity surveys and physiological characterization of laboratory strains to investigate substrate-attached filamentous microbial biofilms at Tor Caldara, a shallow-water gas vent in the Tyrrhenian Sea. At this site, the venting gases are mainly composed of CO2 and H2S and the temperature at the emissions is the same as that of the surrounding water. To investigate the composition of the total and active fraction of the Tor Caldara biofilm communities, we collected established and newly formed filaments and we sequenced the 16S rRNA genes (DNA) and the 16S rRNA transcripts (cDNA). Chemoautotrophic sulfur-oxidizing members of the Gammaproteobacteria (predominantly Thiotrichales) dominate the active fraction of the established microbial filaments, while Epsilonproteobacteria (predominantly Sulfurovum spp.) are more prevalent in the young filaments. This indicates a succession of the two communities, possibly in response to age, sulfide and oxygen concentrations. Growth experiments with representative laboratory strains in sulfide gradient medium revealed that Sulfurovum riftiae (Epsilonproteobacteria) grew closer to the sulfide source than Thiomicrospira sp. (Gammaproteobacteria, Thiotrichales). Overall, our findings show that sulfur-oxidizing Epsilonproteobacteria are the dominant pioneer colonizers of the Tor Caldara biofilm communities and that Gammaproteobacteria become prevalent once the community is established. This succession pattern appears to be driven - among other factors - by the adaptation of Epsilon- and Gammaproteobacteria to different sulfide concentrations.

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Section: Discussionmentioning

confidence: 99%

Ecological Succession of Sulfur-Oxidizing Epsilon- and Gammaproteobacteria During Colonization of a Shallow-Water Gas Vent

et al. 2018

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“…In this regard, detection of a magmatic chamber containing some melt fraction could mean the potential for reactivation even after several tens of kiloyears dormancy. Emission of gases with isotopic signatures in the range of magmatic values can be evidence of magma intrusions at depth (Bräuer et al, 2008(Bräuer et al, , 2018Caracausi et al, 2013Caracausi et al, , 2015Carapezza et al, 2003Carapezza et al, , 2012Carapezza & Tarchini, 2007;Farrar et al, 1995;Pizzino et al, 2002;Rouwet et al, 2014Rouwet et al, , 2017Sano et al, 2015;Sorey et al, 1998), in addition to recognition of geophysical anomalies reflecting melt pockets at depth (Comeau et al, 2015(Comeau et al, , 2016Harangi, Novák, et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

Noble Gas and Carbon Isotope Systematics at the Seemingly Inactive Ciomadul Volcano (Eastern‐Central Europe, Romania): Evidence for Volcanic Degassing

Kis

Caracausi

Palcsu

et al. 2019

Geochem Geophys Geosyst

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Ciomadul is the youngest volcano in the Carpathian‐Pannonian Region, Eastern‐Central Europe, which last erupted 30 ka. This volcano is considered to be inactive, however, combined evidence from petrologic and magnetotelluric data, as well as seismic tomography studies, suggests the existence of a subvolcanic crystal mush with variable melt content. The volcanic area is characterized by high CO2 gas output rate, with a minimum of 8.7 × 103 t/year. We investigated 31 gas emissions at Ciomadul to constrain the origin of the volatiles. The δ13C–CO2 and 3He/4He compositions suggest the outgassing of a significant component of mantle‐derived fluids. The He isotope signature in the outgassing fluids (up to 3.10 Ra) is lower than the values in the peridotite xenoliths of the nearby alkaline basalt volcanic field (R/Ra 5.95 Ra ± 0.01), which are representative of a continental lithospheric mantle and significantly lower than MORB values. Considering the chemical characteristics of the Ciomadul dacite, including trace element and Sr–Nd and O isotope compositions, an upper crustal contamination is less probable, whereas the primary magmas could have been derived from an enriched mantle source. The low He isotopic ratios could indicate a strongly metasomatized mantle lithosphere. This could be due to infiltration of subduction‐related fluids and postmetasomatic ingrowth of radiogenic He. The metasomatic fluids are inferred to have contained subducted carbonate material resulting in a heavier carbon isotope composition (δ13C is in the range of −1.4‰ to −4.6‰) and an increase of CO2/3He ratio. Our study shows the magmatic contribution to the emitted gases.

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“…[1][2][3] A better knowledge of the nature and evolution of deep fluids establishes a fundamental basis for geological studies, [4][5][6] including fault tracing. [7][8][9][10][11][12] In fact, fault zones are known to act as preferential pathways for migrating fluids, that can readily transmit a variety of fluids, including gases, to the surface. 8,9,13 In some cases noble gases could act as indicators of old and recently activated fault segments.…”

Section: Introductionmentioning

confidence: 99%

Radon, helium and uranium survey in some thermal springs located in NW Himalayas, India: mobilization by tectonic features or by geochemical barriers?

Walia

Quattrocchi

Virk³

et al. 2005

J. Environ. Monit.

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Radon, helium and uranium measurements have been carried out in hot water springs in the Parbati and Beas valleys of Himachal Himalaya. Most of these hot springs are known as famous pilgrimage centers. The activity of dissolved radon in the liquid phase is found to vary widely, by an order of magnitude, between 10 and 750 Bq L(-1), whereas, the dissolved helium content in these thermal springs varies between 10 and 100 ppm. The uranium contents are low and vary from <0.01 to 5 microg L(-1). The measured values of radon, helium and uranium are possibly controlled by structural geology, namely the presence of pervious fault systems, and by the lithology of the leached host rocks. Redox-potential geochemical barriers cause the mobilization of uranile ions in solution (UO2+); the most plausible hypothesis is when the conditions are oxidising, confirming the importance of physico-chemical conditions up to the supergenic environment, to control the fluid geochemistry of the U-He-222Rn system. Some evidence is available from both geothermometric considerations and geochemical data which will be reported elsewhere, whereas the present study is focused on U decay series-noble gas geochemistry. The first analysis of collected 3He/4He data is consistent with a crustal signature at the studied thermal springs.

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Untitled

Cited by 46 publications

References 35 publications

Ecological Succession of Sulfur-Oxidizing Epsilon- and Gammaproteobacteria During Colonization of a Shallow-Water Gas Vent

Ecological Succession of Sulfur-Oxidizing Epsilon- and Gammaproteobacteria During Colonization of a Shallow-Water Gas Vent

Noble Gas and Carbon Isotope Systematics at the Seemingly Inactive Ciomadul Volcano (Eastern‐Central Europe, Romania): Evidence for Volcanic Degassing

Radon, helium and uranium survey in some thermal springs located in NW Himalayas, India: mobilization by tectonic features or by geochemical barriers?

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