Palaeoenvironmental implications of a marine geoarchaeological survey conducted in the SW Argosaronic gulf, Greece

AbstractA marine geoarcheological survey was conducted at the southwestern end of the Argosaronic gulf in Greece, an area of archaeological importance. The survey was initiated by the discovery of a Late Bronze Age (LBA) shipwreck off Modi Islet. The survey which employed echo-sounding, sub-bottom profiling, side scan sonar systems and sediment coring extended to the area between Poros Island, Modi Islet and Argolid peninsula, aiming to evaluate the changes of the coastal zone extent in the past. The evolution of the palaeo-shoreline over the last 20ka is proposed based on the interpretation of the acquired bathymetric and seismic records, the estimation of the thickness of the marine sediments and the examination of existing datasets of the relative sea level changes in the area.The produced scenarios suggest that major changes marked the extent of the coastal zone since the Paleolithics. During the Upper Paleolithic period, the coast was larger by at least 11km2 and Poros and Modi islands were connected to the Peloponnesus. The sea level rise during the Mesolithic period formed a well-protected bay between Poros Island and Peloponessus and disconnected the Modi Islet from Poros Island. The coastal zone reached the present configuration around Late Bronze Age. The detection and mapping of scarps on the seismic profiles imply that the sea level rise presented standstills at least from the Last Glacial maximum until the onset of Holocene. However, the submerged coasts could be potential areas of archaeological interest since the examined area is habited continuously from the Paleolithic period.The acoustic data sets produced high resolution geomorphological maps at the wreck site which constitute data base for the monitoring of the site. In addition, the examination of the seafloor texture at the wreck site suggests that the seafloor characteristics were unfavorable for the preservation of the shipwreck

Offshore and onshore seepage of thermogenic gas at Katakolo Bay (Western Greece)

Considerable seepage of natural gas occurs throughout the Katakolo Bay, both at sea and on land, along the Ionian coast of Peloponnesus (Western Greece). Explosive levels of CH4 and toxic concentrations of H2S accumulating in the ground, pose a severe hazard for humans and tourist infrastructures. A wide offshore and onshore gas survey, including marine remote sensing, underwater exploration by a towed instrumented system, compositional and isotopic analyses, and flux measurements of gas, allowed us to assess that: (a) gas seepage takes place along two main normal faults; (b) offshore side-scan sonographs recorded at least 823 gas bubble plumes over an area of 94,200 m2, at depths ranging from 5.5 to 16 m; (c) offshore and onshore seeps release the same type of thermogenic gas (δ13CCH4~−34 to −36‰); (d) offshore gas showed increased stable carbon isotopic ratio of CO2 and propane, which suggests enhanced biodegradation of hydrocarbons; (e) isotopic data combined with thermogenic gas generation modeling and maturity plots, suggest that the gas is related to a deep Petroleum System with Jurassic carbonate reservoirs, Triassic source rocks, and Triassic evaporites; (f) H2S (δ34S: +2.4‰) is produced by thermochemical sulfate reduction in deep anhydrites, in contact with hydrocarbon-rich carbonates; (g) due to the shallow depth, more than 90% of CH4 released at the seabed enters the atmosphere, consistent with theoretical bubble dissolution models, with a mean plume output of 0.12 kg d−1; total offshore CH4 output was estimated in the range of 33 to 120 t y−1; and (h) in the onshore area at least 50 gas vents in the harbor and a large seep on the adjacent Faros hill, emit in total about 89 t CH4 y−1. Katakolo results to be one of the biggest thermogenic gas seepage zones in Europe.Published115–1264.5. Studi sul degassamento naturale e sui gas petroliferiJCR Journalrestricte

Methane flux and origin in the Othrys ophiolite hyperalkaline springs, Greece

The occurrence and origin of methane (CH4) generated by serpentinization of ultramafic rocks is of current timely interest in planetary geology, astrobiology and energy resource exploration, as it may contribute, in particular, to decipher the source of methane on Mars, the origin of life and the potential of abiotic hydrocarbon synthesis. Methane of dominant abiotic origin in serpentinized peridotites on continents (ophiolites or igneous intrusions) has been documented so far, with complete carbon and hydrogen isotope composition, in six countries, in the Philippines, Turkey, Oman, New Zealand, Japan and Italy. We report the discovery of two new sites in Greece, at Archani and Ekkara, located in the Othrys ophiolite massif. Portable sensors based on Fourier Transform InfraRed spectrometry (FTIR) and Tunable Diode Laser Absorption Spectroscopy (TDLAS) allowed to realize that out of 21 ophiolitic springs, methane is released only by four hyperalkaline (pH from 10.7 to 11.3) and calcium hydroxide (Ca–OH) type waters; all other 17 springs with pH b 8.7 and magnesium-rich waters in the Pindos, Vourinos and Veria ophiolites, do not show methane. This correlation between gas occurrence and water type seems to occur worldwide; accordingly, CH4 production appears to be intimately related to the depth and residence time of the circulating meteoric waters. Methane is emitted into the atmosphere also from the soil surrounding the hyperalkaline springs, with fluxes of the same order of magnitude (~102–103 mg m−2 day−1) of seepage typically observed over conventional petroleum systems. Othrys CH4 has an isotopic composition (δ13C from −27‰ to −37.3‰ VPDB, δ2H from −250‰ to −311‰ VSMOW) similar to that reported in ultramafic rocks in New Zealand and Japan, and in Precambrian crystalline shields, which were considered dominantly abiotic and probably derived from Fischer–Tropsch Type reactions. The paucity of CO2, which is the norm in hyperalkaline waters, and of other hydrocarbons prevents from evaluating possible mixing of gas of different sources, including microbial methanogenesis. Also the H2 content is trivial, notwithstanding it being a typical product of serpentinization; this could be due to complete H2 consumption by CO2 reduction in a limited or decreased H2 production system due, for example, to a late stage of increased silica activity, as suggested by preliminary petrographic observations. The low geothermal gradient of the area and the present-day serpentinization imply that,whatever the CH4 production mechanism, it took place at temperatures below those traditionally considered for the origin of abiotic methane in hydrothermal systems

Methane flux and origin in the Othrys ophiolite hyperalkaline springs, Greece

The occurrence and origin of methane (CH4) generated by serpentinization of ultramafic rocks is of current timely interest in planetary geology, astrobiology and energy resource exploration, as it may contribute, in particular, to decipher the source of methane on Mars, the origin of life and the potential of abiotic hydrocarbon synthesis. Methane of dominant abiotic origin in serpentinized peridotites on continents (ophiolites or igneous intrusions) has been documented so far, with complete carbon and hydrogen isotope composition, in six countries, in the Philippines, Turkey, Oman, New Zealand, Japan and Italy. We report the discovery of two new sites in Greece, at Archani and Ekkara, located in the Othrys ophiolite massif. Portable sensors based on Fourier Transform InfraRed spectrometry (FTIR) and Tunable Diode Laser Absorption Spectroscopy (TDLAS) allowed to realize that out of 21 ophiolitic springs, methane is released only by four hyperalkaline (pH from 10.7 to 11.3) and calcium hydroxide (Ca–OH) type waters; all other 17 springs with pH b 8.7 and magnesium-rich waters in the Pindos, Vourinos and Veria ophiolites, do not show methane. This correlation between gas occurrence and water type seems to occur worldwide; accordingly, CH4 production appears to be intimately related to the depth and residence time of the circulating meteoric waters. Methane is emitted into the atmosphere also from the soil surrounding the hyperalkaline springs, with fluxes of the same order of magnitude (~102–103 mg m−2 day−1) of seepage typically observed over conventional petroleum systems. Othrys CH4 has an isotopic composition (δ13C from −27‰ to −37.3‰ VPDB, δ2H from −250‰ to −311‰ VSMOW) similar to that reported in ultramafic rocks in New Zealand and Japan, and in Precambrian crystalline shields, which were considered dominantly abiotic and probably derived from Fischer–Tropsch Type reactions. The paucity of CO2, which is the norm in hyperalkaline waters, and of other hydrocarbons prevents from evaluating possible mixing of gas of different sources, including microbial methanogenesis. Also the H2 content is trivial, notwithstanding it being a typical product of serpentinization; this could be due to complete H2 consumption by CO2 reduction in a limited or decreased H2 production system due, for example, to a late stage of increased silica activity, as suggested by preliminary petrographic observations. The low geothermal gradient of the area and the present-day serpentinization imply that,whatever the CH4 production mechanism, it took place at temperatures below those traditionally considered for the origin of abiotic methane in hydrothermal systems.Published161-1747A. Geofisica di esplorazioneJCR Journalrestricte

A Neutral Wind Instrument for Nano-Satellite Platforms

Here we describe the first neutral wind sensor developed specifically for use on resource limited nano-satellite platforms. The instrument is a next generation redesign of the ram wind sensor flown on the Communications/Navigation Outage Forecasting System satellite for measurements of neutral velocity, temperature, and composition. Results of subsystem tests in vacuum conditions show low-power operation, promising design, and good resolution of measured parameters over the operational pressure and energy ranges expected in the low Earth orbit environment

Modulation of IL-6/STAT3 signaling axis in CD41FOXP32 T cells represents a potential antitumor mechanism of azacitidine

CD+1 T cells orchestrate immune responses and are actively engaged in shaping tumor immunity. Signal transducer and activator of transcription (STAT) signaling controls the epigenetic tuning of CD+1 T-cell differentiation and polarization, and perturbed STAT signaling networks in CD+1 T cells subvert antitumor immunity in malignancies. Azacitidine (AZA), the mainstay therapy for high-risk myelodysplastic syndromes (HR-MDS), affects CD+1 T-cell polarization and function, but whether this contributes to AZA efficacy is currently unknown. By using functional proteomic, transcriptomic, andmutational analyses in 73 HR-MDS patients undergoing AZA therapy, we demonstrate that responding patients exhibited a coordinated CD+1 T-cell immune response and downregulated the inflammatory cytokine signaling pathways in CD+1 T cells after AZA, in contrast to nonresponders who upregulated the same pathways. We further observed an AZA-mediated downregulation of intereukin-6 (IL-6)- induced STAT3 phosphorylation in CD+1FOXP32 conventional T cells (Tcons) that correlated independently with better response and survival, whereas it was also not associated with the mutation number and profile of the patients. The AZA-induced downregulation of IL-6/STAT3 axis in Tcons restored the STAT signaling architecture in CD+1 T-cell subsets, whereas STAT signaling networks remained disorganized in patients who upregulated IL-6/STAT3 activity in Tcons. Given the pivotal role of CD+1 T cells in adaptive immunity, our findings suggest that the downregulation of the IL-6/STAT3 pathway in Tcons potentially constitutes a previously unrecognized immune-mediatedmechanism of action of AZA and sets the scene for developing rational strategies of AZA combinations with IL-6/STAT3 axis inhibitors. © 2021 by The American Society of Hematology