The biocomplexity of sediment communities along a 120m transect near an arsenic-rich, shallow marine hydrothermal vent at Tutum Bay, Papua New Guinea was thoroughly examined. A count of macroand meiofaunal organisms was combined with bacterial and eukaryotic SSU rRNA gene surveys to assess biodiversity. Each site along the transect had distinct microbial communities. Near-vent sites were more s...

Thermophilic methanogens are common autotrophs at hydrothermal vents, but their growth constraints and dependence on H2 syntrophy in situ are poorly understood. Between 2012 and 2015, methanogens and H2-producing heterotrophs were detected by growth at 80°C and 55°C at most diffuse (7-40°C) hydrothermal vent sites at Axial Seamount. Microcosm incubations of diffuse hydrothermal fluids at 80°C a...

Introduction: The Cassini spacecraft detected a gas plume emanating from Saturn’s icy satellite Enceladus [13]. Its composition (91% H2O, 3.2% CO2, 4% N2, and 1.6% CH4) was inferred based on measurements by the Ion and Neutral Mass Spectrometer [2]. Jets from warm (110-160 K) fissures (“sulci”) supply the plume [3], and boiling water in a subsurface reservoir may power the jets [1]. Liquid wate...

[1] Ground surface displacement (GSD) in large calderas is often interpreted as resulting from magma intrusion at depth. Recent advances in geodetic measurements of GSD, notably interferometric synthetic aperture radar, reveal complex and multifaceted deformation patterns that often require complex source models to explain the observed GSD. Although hydrothermal fluids have been discussed as a ...

Shallow-sea (5 m depth) hydrothermal venting off Milos Island provides an ideal opportunity to target transitions between igneous abiogenic sulfide inputs and biogenic sulfide production during microbial sulfate reduction. Seafloor vent features include large (>1 m(2)) white patches containing hydrothermal minerals (elemental sulfur and orange/yellow patches of arsenic-sulfides) and cells of su...

To directly access the sub-seafloor microbial communities, seafloor drilling has been done in a deep-sea hydrothermal field of the Suiyo Seamount, Izu-Bonin Arc, Western Pacific. In the present study, crustal fluids were collected from the boreholes, and the bacterial and archaeal communities in the fluids were investigated by culture-independent molecular analysis based on 16S rRNA gene sequen...

sakhtehesar mountain is located in urumieh-dokhtar magmatic belt and is composed of volcanic and subvolcanic rocks (pliocene andesite to dacite) which intruded the volcanics and pyroclastics of paleocene age. three alteration zones including potassic, phyllic and propylitic are recognized in the area. in this paper, the mineral chemistry of magmatic and primary biotite and the mineral chemistry...

The concentration of halogens (Cl, Br) and sulfate in seawater during the Archaean eon have important implications for the evolution of Earth’s hydrosphere and atmosphere and the development of early life. Insights into the composition of Archaean seawater and hydrothermal fluids can be obtained by direct analysis of fluid inclusions preserved in Archaean sediments and hydrothermal systems. Her...

[1] Isotopic analyses of dissolved molybdenum are presented for sediment pore waters from a reducing sedimentary basin and for fluids from a low-temperature ridge flank hydrothermal system. dMo in these fluids range from 0.8 to 3.5% (relative to a laboratory standard), demonstrating that marine sedimentary reactions significantly fractionate Mo isotopes. Within the upper 3 cm of sediment, manga...

Estimates of ocean temperatures on Earth 3.5 billion years ago (Ga) range between 26° and 85°C. We present new data from 3.47- to 3.43-Ga volcanic rocks and cherts in South Africa suggesting that these temperatures reflect mixing of hot hydrothermal fluids with cold marine and terrestrial waters. We describe fossil hydrothermal pipes that formed at ~200°C on the sea floor >2 km below sea level....