ALBERT

Description: Foraminifera are unicellular eukaryotic organisms that live individually autonomous in the sea (Hottinger, 2005). They form mechanically resistant tests, either by gluing material found in the environment or by secreting organic or calcareous shells. Along with the test, main characteristic of foraminifera are their pseudopodia emerging from the cell body through multiple apertures. Foraminifera are extremely abundant in marine sediments, which makes them useful in recent and fossil paleoenvironmental studies. The first simple forms of foraminifera appeared in Cambrian and since provide a long and well recorded evolutionary record throughout Paleozoic, Mesozoic and Cenozoic (BouDagher‐ Fadel, 2008). Based on life strategy, foraminifera are divided in two groups: benthic and planktonic foraminifera. Planktonic foraminifera passively float through the waters of open oceans moved by currents. Benthic foraminifera live on the sea floor; on the surface, buried into the sediment, or attached to plants, rocks or sediment particles. Based on their size and internal morphological structure benthic foraminifera can be divided into two groups; smaller and larger benthic foraminifera. The main criteria for identifying LBF is the complex internal structure which evolved to efficiently host photosymbionts, the key elements in the ecology of LBF. The symbiotic algae utilize the waste product of the foraminifera, allowing them to efficiently recycle of nutrients and to facilitate calcification (Ross, 1974; Leutenegger, 1984). This life strategy, LBF as a greenhouse, limits their occurrences to photic zone since algal symbionts are dependent on light for photosynthesis (Leutenegger, 1984). Besides light levels, the distribution and abundance of LBF is determined by relatively well‐known parameters, including hydrodynamic energy, water temperature, salinity, food availability and substrate type (Hottinger, 1983; Hohenegger, 1994; Renema, 2006). Therefore, the assemblage composition of fossil LBF can provide important and valuable data for paleoenvironmental reconstructions (Hallock and Glenn, 1986; Renema and Troelstra, 2001). Present day Southeast Asia represents the region that supports the most diverse marine ecosystems on Earth. The origin of this biodiversity is still unresolved, but it is proposed to be present at least since the Early Miocene (Renema et al., 2008). Therefore, the data acquired from the fossil assemblages may contribute to our understanding of this biodiversity hotspot. In this thesis Miocene LBF were investigated in order to provide new insights regarding their biostratigraphy and depositional paleonvironments of Indonesia. The focus of the research includes mixed carbonate‐siliciclastic (MCS) systems of the Kutai Basin in East Kalimantan. However, to provide a comparative model with the blue‐water systems (Wilson, 2012), the study also included localities from Bulu Formation with carbonate platform deposits in Central Java. Until recently, MCS systems were considered to be environments inhospitable for carbonate producers compared to the blue‐water marine systems, and hence were often neglected in biodiversity studies (Friedman, 1988). However, recent studies reveal high biodiversity in these turbid water settings, including corals (Santodomingo et al., in press), LBF (Novak and Renema, in press), algae (Rosler et al., in press), and bryozoans (Di Martino and Taylor, 2014). The Kutai Basin was a host for the development of numerous MCS systems, with a peak of their deposition during the Miocene (Wilson and Rosen, 1998; Wilson, 2005). Herein MCS systems are defined as in situ mixing (Mount, 1984) with the carbonate fraction consisting of autochthonous or parautochthonous death assemblages of calcareous organisms accumulated on or within siliciclastic substrates. In these systems LBF are important contributors to carbonate production, and combined with their high tolerance of terrigenous input, individually they are the most suitable taxa for paleoenvironmental reconstruction and interpretation in MCS systems (Lokier et al., 2009; Novak et al., 2013). By investigating LBF assemblages of Miocene MCS systems of the Kutai Basin by updating their biostratigraphy, providing environmental reconstructions, and comparing them with contemporaneous carbonate platform deposits, this research helps in untangling the origins of the Indo‐Pacific biodiversity hotspot.

Description: The jumbo squid, Dosidicus gigas, can survive extended forays into the oxygen minimum zone (OMZ) of the Eastern Pacific Ocean. Previous studies have demonstrated reduced oxygen consumption and a limited anaerobic contribution to ATP production, suggesting the capacity for substantial metabolic suppression during hypoxic exposure. Here, we provide a more complete description of energy metabolism and explore the expression of proteins indicative of transcriptional and translational arrest that may contribute to metabolic suppression. We demonstrate a suppression of total ATP demand under hypoxic conditions (1% oxygen, PO2=0.8 kPa) in both juveniles (52%) and adults (35%) of the jumbo squid. Oxygen consumption rates are reduced to 20% under hypoxia relative to air-saturated controls. Concentrations of arginine phosphate (Arg-P) and ATP declined initially, reaching a new steady state (~30% of controls) after the first hour of hypoxic exposure. Octopine began accumulating after the first hour of hypoxic exposure, once Arg-P breakdown resulted in sufficient free arginine for substrate. Octopine reached levels near 30 mmol g−1 after 3.4 h of hypoxic exposure. Succinate did increase through hypoxia but contributed minimally to total ATP production. Glycogenolysis in mantle muscle presumably serves to maintain muscle functionality and balance energetics during hypoxia. We provide evidence that post-translational modifications on histone proteins and translation factors serve as a primary means of energy conservation and that select components of the stress response are altered in hypoxic squids. Reduced ATP consumption under hypoxia serves to maintain ATP levels, prolong fuel store use and minimize the accumulation of acidic intermediates of anaerobic ATP-generating pathways during prolonged diel forays into the OMZ. Metabolic suppression likely limits active, daytime foraging at depth in the core of the OMZ, but confers an energetic advantage over competitors that must remain in warm, oxygenated surface waters. Moreover, the capacity for metabolic suppression provides habitat flexibility as OMZs expand as a result of climate change.

Description: A geochemical survey of the main thermal waters discharging in the southwestern part of the Domuyo volcanic complex (Argentina),where the latest volcanic activity dates to 0.11 Ma, has highlighted the extraordinarily high heat loss from this remote site in Patagonia. The thermal water discharges are mostly Na-Cl in composition and have TDS values up to 3.78 g L−1 (El Humazo). A simple hydrogeochemical approach shows that 1,100 to 1,300 kg s−1 of boiling waters, which have been affected by shallow steam separation, flow into the main drainage of the area (Rio Varvarco). A dramatic increase of the most conservative species such as Na, Cl and Li from the Rio Varvarco fromupstreamto downstreamwas observed and related solely to the contribution of hydrothermal fluids. The equilibrium temperatures of the discharging thermal fluids, calculated on the basis of the Na-K-Mg geothermometer, are between 190 °C and 230 °C. If we refer to a liquid originally at 220 °C (enthalpy = 944 J g−1), the thermal energy release can be estimated as high as 1.1±0.2 GW, a value that ismuch higher than the natural release of heat in other important geothermal fields worldwide, e.g., Mutnovsky (Russia), Wairakei (New Zealand) and Lassen Peak (USA). This value is the second highest measured advective heat flux from any hydrothermal system on Earth after Yellowstone.

Description: Published

Description: 71–77

Description: 4V. Vulcani e ambiente

Description: JCR Journal

Description: restricted

Description: Abstract A geochemical survey of fumarolic and submerged gases from fluid discharges located in the Nea Kameni and Palea Kameni islets (Santorini Island, Greece) was carried out before, during, and after the unrest related to the anomalously high seismic and ground deformation activity that affected this volcanic system since January 2011. Our data show that from May 2011 to February 2012, the Nea Kameni fumaroles showed a significant increase of H2 concentrations. After this period, an abrupt decrease in the H2 contents, accompanied by decreasing seismic events, was recorded. A similar temporal pattern was shown by the F−, Cl−, SO4 2−, and NH4 + concentrations in the fumarolic condensates. During the sharp increase of H2 concentrations, when values up to 158 mmol/ mol were measured, the δ13C–CO2 values, which prior to January 2011 were consistent with a dominant CO2 thermometamorphic source, have shown a significant decrease, suggesting an increase of mantle CO2 contribution. Light hydrocarbons, including CH4, which are controlled by chemical reactions kinetically slower than H2 production from H2O dissociation, displayed a sharp increase in March 2012, under enhanced reducing conditions caused by the high H2 concentrations of May 2011–February 2012. The general increase in light hydrocarbons continued up to July 2012, notwithstanding the contemporaneous H2 decrease. The temporal patterns of CO2 concentrations and N2/Ar ratios increased similarly to that of H2, possibly due to sealing processes in the fumarolic conduits that diminished the contamination related to the entrance of atmospheric gases in the fumarolic conduits. The compositional evolution of the Nea Kameni fumaroles can be explained by a convective heat pulse from depth associated with the seismic activation of the NE–SW-oriented Kameni tectonic lineament, possibly triggered by either injection of new magma below Nea Kameni island, as apparently suggested by the evolution of the seismic and ground deformation activity, or increased permeability of the volcanic plumbing system resulting from the tectonic movements affecting the area. The results of the present study demonstrate that the geophysical and geochemical signals at Santorini are interrelated and may be precursory signals of renewed volcanic activity and encourage the development of interdisciplinary monitoring program to mitigate the volcanic risk in the most tourist-visited island of the Mediterranean Sea.

Description: Published

Description: 711

Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive

Description: 2.4. TTC - Laboratori di geochimica dei fluidi

Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi

Description: JCR Journal

Description: restricted

Description: Copahue volcano is part of the Caviahue–Copahue Volcanic Complex (CCVC),which is located in the southwestern sector of the Caviahue volcano-tectonic depression (Argentina–Chile). This depression is a pull-apart basin accommodating stresses between the southern Liquiñe–Ofqui strike slip and the northern Copahue–Antiñir compressive fault systems, in a back-arc setting with respect to the Southern Andean Volcanic Zone. In this study, we present chemical (inorganic and organic) and isotope compositions (δ13C-CO2, δ15N, 3He/4He, 40Ar/36Ar, δ13C-CH4, δD-CH4, and δD-H2O and δ18O-H2O) of fumaroles and bubbling gases of thermal springs located at the foot of Copahue volcano sampled in 2006, 2007 and 2012. Helium isotope ratios, the highest observed for a Southern American volcano (R/Ra up to 7.94), indicate a non-classic arc-like setting, but rather an extensional regime subdued to asthenospheric thinning. δ13C-CO2 values (from −8.8‰ to −6.8‰ vs. V-PDB), δ15N values (+5.3‰ to +5.5‰ vs. Air) and CO2/3He ratios (from 1.4 to 8.8 × 109) suggest that the magmatic source is significantly affected by contamination of subducted sediments. Gases discharged from the northern sector of the CCVC show contribution of 3He-poor fluids likely permeating through local fault systems. Despite the clear mantle isotope signature in the CCVC gases, the acidic gas species have suffered scrubbing processes by a hydrothermal system mainly recharged by meteoric water. Gas geothermometry in the H2O-CO2-CH4-CO-H2 system suggests that CO and H2 re-equilibrate in a separated vapor phase at 200°–220 °C. On the contrary, rock–fluid interactions controlling CO2, CH4 production from Sabatier reaction and C3H8 dehydrogenation seem to occur within the hydrothermal reservoir at temperatures ranging from 250° to 300 °C. Fumarole gases sampled in 2006–2007 show relatively low N2/He and N2/Ar ratios and high R/Ra values with respect to those measured in 2012. Such compositional and isotope variations were likely related to injection of mafic magma that likely triggered the 2000 eruption. Therefore, changes affecting the magmatic systemhad a delayed effect on the chemistry of the CCVC gases due to the presence of the hydrothermal reservoir. However, geochemical monitoring activities mainly focused on the behavior of inert gas compounds (N2 and He), should be increased to investigate the mechanism at the origin of the unrest started in 2011.

Description: Published

Description: 44–56

Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive

Description: 2.4. TTC - Laboratori di geochimica dei fluidi

Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi

Description: JCR Journal

Description: restricted

Description: Measurements of soil fluxes of hydrothermal gases, with special emphasis on C6H6, as well as chemical composition of mono-aromatic compounds in fumaroles and air, were carried out in April 2012 at the Solfatara crater (Campi Flegrei, Southern Italy) to investigate the distribution and behavior of these species as they migrate through the soil from their deep source to the atmosphere. Soil fluxes of CO2, CH4 and C6H6 exhibit good spatial correlation, suggesting that diffuse degassing is mainly controlled by local fractures. The calculated total output of diffuse C6H6 from Solfatara is 0.10 kg day 1, whereas fluxes of CO2 and CH4 are 79 103 and 1.04 kg day 1, respectively. A comparison between soil gas fluxes and fumarole composition reveals that within the crater soil CH4 is significantly affected by oxidation processes, which are more efficient for low gas fluxes, being dependent on the residence time of the uprising hydrothermal gases at shallow depth. Benzene degradation, mainly proceeding through oxidation via benzoate, seems to be strongly controlled by the presence of a shallow SO2 4 -rich aquifer located in the central and southwestern sectors of the crater, suggesting that the process is particularly efficient when SO2 4 acts as terminal electron acceptor (SO4 reduction). Relatively high C6H6/C7H8 ratios, typical of hydrothermal fluids, were measured in air close to the main fumarolic field of Solfatara crater. Here, C6H6 concentrations, whose detection limit is 0.1 lgm 3, are more than one order of magnitude higher than the limit value for ambient air (5 lgm 3). This suggests that hydrothermal fluids have a strong impact on air quality in the immediate surroundings of the fumarolic vents. Significant concentrations of endogenous mono-aromatics were also detected in air samples collected from the northern and western sides of the crater, where these gas compounds are mostly fed by diffuse degassing through the crater bottom soil.

Description: Published

Description: 142–153

Description: 1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive

Description: 2.4. TTC - Laboratori di geochimica dei fluidi

Description: 4.5. Studi sul degassamento naturale e sui gas petroliferi

Description: JCR Journal

Description: restricted

Description: Episodic gas seepage occurs at the seafloor in the Gulf of Izmit (Sea of Marmara, NW Turkey) along the submerged segment of the North Anatolian Fault (NAF), which ruptured during the 1999 Mw7.4 Izmit earthquake, and caused tectonic loading of the fault segment in front of the Istanbul metropolitan area. In order to study gas seepage and seismic energy release along the NAF, a multiparametric benthic observatory (SN-4) was deployed in the gulf at the western end of the 1999 Izmit earthquake rupture, and operated for about 1 yr at 166 m water depth. The SN-4 payload included a three-component broad-band seismometer, as well as gas and oceanographic sensors. We analysed data collected continuously for 161 d in the first part of the experiment, from 2009 October to 2010 March. The main objective of our work was to verify whether tectonic deformation along the NAF could trigger methane seepage. For this reason, we considered only local seismicity, that is, within 100 km from the station. No significant (ML ≥ 3.6) local earthquakes occurred during this period; on the other hand, the seismometer recorded high-frequency SDEs (short duration events), which are not related to seismicity but to abrupt increases of dissolved methane concentration in the sea water that we called MPEs (methane peak events). Acquisition of current velocity, dissolved oxygen, turbidity, temperature and salinity, allowed us to analyse the local oceanographic setting during each event, and correlate SDEs to episodic gas discharges from the seabed. We noted that MPEs are the result of such gas releases, but are detected only under favourable oceanographic conditions. This stresses the importance of collecting long-term multiparametric time-series to address complex phenomena such as gas and seismic energy release at the seafloor. Results from the SN-4 experiment in the Sea of Marmara suggest that neither low-magnitude local seismicity, nor regional events affect intensity and frequency of gas flows from the seafloor.

Description: Published

Description: 850-866

Description: 1T. Geodinamica e interno della Terra

Description: 3A. Ambiente Marino

Description: 7A. Geofisica di esplorazione

Description: JCR Journal

Description: restricted