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UNLABELLED Sulfur is an important element in sustaining microbial communities present in hydrothermal vents. Sulfur oxidation has been extensively studied due to its importance in chemosynthetic pathways in hydrothermal fields; however, less is known about sulfate reduction. Here, the metagenomes of hydrothermal chimneys located on the ultraslow-spreading Southwest Indian Ridge (SWIR) were pyro...
Introduction: The persistence of lithospheric thickness variations from its earliest era provides constraints on the thermal evolution of Mars [1,2]. Under these constraints, plausible thermal evolution models require cooling of the crust that could be accomplished by either hydrothermal cooling in a fractured portion of the upper crust or the existence of a stable stratified mantle where heat-...
Non-magmatic, fracture-controlled hydrothermal systems located within and near the Idaho batholith have been examined and evaluated for potential application as natural analogues to high-level nuclear waste repositories. Detailed geochemical, Ž . petrologic, and structural studies of hot springs along the South Fork of the Payette River SFPR in central Idaho, USA, have been combined to assess t...
Shallow-sea hydrothermal systems experience continuous fluctuations of physicochemical conditions due to seawater influx which generates variable habitats, affecting the phylogenetic composition and metabolic potential of microbial communities. Until recently, studies of submarine hydrothermal communities have focused primarily on chemolithoautotrophic organisms, however, there have been limite...
Indian Ocean hydrothermal vents are believed to represent a novel biogeographic province, and are host to many novel genera and families of animals, potentially indigenous to Indian Ocean hydrothermal systems. In particular, since its discovery in 2001, much attention has been paid to a so-called 'scaly-foot' gastropod because of its unique iron-sulfide-coated dermal sclerites and the chemosynt...
The effects of various additives, such as an inorganic alkali and metal catalyst, on the hydrothermal process were examined to recover hydrogen from biomass with high efficiency and selectivity at relatively low temperatures around 400°C. At first, a cellulose sample as a model biomass was subjected to the hydrothermal process at 400°C under 25 MPa in the presence of an alkali, sodium carbonate...
We report the synthesis of nanoapatite crystals via a hydrothermal reaction of hydroxyapatite precipitates. The impact of the reaction conditions on the properties of the crystals obtained were evaluated. The hydrothermal reaction that takes place markedly affected the crystallinity, morphology, and size of the nanoapatite crystals formed. High crystallinity and large crystal size were obtained...
The Lost City Hydrothermal Field, an ultramafic-hosted system located 15 km west of the Mid-Atlantic Ridge, has experienced at least 30,000 years of hydrothermal activity. Previous studies have shown that its carbonate chimneys form by mixing of approximately 90 degrees C, pH 9-11 hydrothermal fluids and cold seawater. Flow of methane and hydrogen-rich hydrothermal fluids in the porous interior...
Shea, M. and Foland, K.A., 1986. The Marysvale Natural Analog Study: Preliminary oxygen isotope relations. In: N.A. Chapman and J.A.T. Smellie (Guest-Editors), Natural Analogues to the Conditions around a Final Repository for High-level Radioactive Waste. Chem. Geol., 55: 281--295. Rocks of and around the Marysvale mining area in central Utah, U.S.A., have experienced massive, subsolidus hydrot...
[1] Observations from the East Pacific Rise (EPR) and the Endeavour segment of the Juan de Fuca Ridge show that local earthquake swarms can lead to increased hydrothermal venting temperatures after a delay of several days. I develop two models for this process. In the temperature perturbation model, a new pathway opens to a heat source, and the temperatures of fluids leaving the reaction zone i...
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