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Dimitry Y Sorokin, Enzo Messina, Francesco Smedile, Pawel Roman, Jaap S Sinninghe Damsté, Sergio Ciordia, Maria Carmen Mena, Manuel Ferrer, Peter N Golyshin, Ilya V Kublanov, Nazar I Samarov, Stepan V Toshchakov, Violetta La Cono, Michail M Yakimov
Hypersaline anoxic habitats harbour numerous novel uncultured archaea whose metabolic and ecological roles remain to be elucidated. Until recently, it was believed that energy generation via dissimilatory reduction of sulfur compounds is not functional at salt saturation conditions. Recent discovery of the strictly anaerobic acetotrophic Halanaeroarchaeum compels to change both this assumption and the traditional view on haloarchaea as aerobic heterotrophs. Here we report on isolation and characterization of a novel group of strictly anaerobic lithoheterotrophic haloarchaea, which we propose to classify as a new genus Halodesulfurarchaeum...
January 20, 2017: ISME Journal
David Deamer
At some point in early evolution, life became cellular. Assuming that this step was required for the origin of life, there would necessarily be a pre-existing source of amphihilic compounds capable of assembling into membranous compartments. It is possible to make informed guesses about the properties of such compounds and the conditions most conducive to their self-assembly into boundary structures. The membranes were likely to incorporate mixtures of hydrocarbon derivatives between 10 and 20 carbons in length with carboxylate or hydroxyl head groups...
January 17, 2017: Life
Liyang Yang, Wan-E Zhuang, Chen-Tung Arthur Chen, Bing-Jye Wang, Fu-Wen Kuo
The submarine hydrothermal systems are extreme environments where active cycling of dissolved organic matter (DOM) may occur. However, little is known about the optical properties and bioavailability of hydrothermal DOM, which could provide valuable insights into its transformation processes and biogeochemical reactivity. The quantity, quality, and bioavailability of DOM were investigated for four very different hydrothermal vents east of Taiwan, using dissolved organic carbon (DOC), absorption spectroscopy, and fluorescence excitation-emission matrices-parallel factor analysis (EEM-PARAFAC)...
January 3, 2017: Water Research
Hongjun Zhu, Jiahui You, Honglei Zhao
The time taken for spilt oil to appear firstly at the sea surface and its location are two key issues for emergency response. The underwater spread of oil spill in a shear flow was studied experimentally in a re-circulating water channel. The high speed imaging technology was employed to record the whole transport process of oil spilt from a leak of a submarine pipe to the surface. Based on the experimental results, three underwater transport types are identified, which are single droplet pattern (model A), linear chain pattern (model B) and oil plume pattern (model C), respectively...
January 5, 2017: Marine Pollution Bulletin
Jiandong Chen, Tianying Chang, Qunjian Fu, Jinpeng Lang, Wenzhi Gao, Zhongmin Wang, Miao Yu, Yanbo Zhang, Hong-Liang Cui
For the implementation of an all fiber observation network for submarine seismic monitoring, a tri-component geophone based on Michelson interferometry is proposed and tested. A compliant cylinder-based sensor head is analyzed with finite element method and tested. The operation frequency ranges from 2 Hz to 150 Hz for acceleration detection, employing a phase generated carrier demodulation scheme, with a responsivity above 50 dB re rad/g for the whole frequency range. The transverse suppression ratio is about 30 dB...
December 28, 2016: Sensors
Jonathan Mertens, Marc Descoteaux
This study documents the growing role of the physician assistant (PA) in the Canadian Armed Forces. PAs have served as the backbone of the Royal Canadian Medical Services' frontline medical operations since 1984, on land, aboard ships and submarines, and domestically in garrison. Candidates begin as medical technicians and receive advanced training to become PAs at midcareer. The current rank of PAs as warrant officers is evolving and a commissioned status is under consideration.
January 2017: JAAPA: Official Journal of the American Academy of Physician Assistants
Magdalena Guardiola, Owen S Wangensteen, Pierre Taberlet, Eric Coissac, María Jesús Uriz, Xavier Turon
We assessed spatio-temporal patterns of diversity in deep-sea sediment communities using metabarcoding. We chose a recently developed eukaryotic marker based on the v7 region of the 18S rRNA gene. Our study was performed in a submarine canyon and its adjacent slope in the Northwestern Mediterranean Sea, sampled along a depth gradient at two different seasons. We found a total of 5,569 molecular operational taxonomic units (MOTUs), dominated by Metazoa, Alveolata and Rhizaria. Among metazoans, Nematoda, Arthropoda and Annelida were the most diverse...
2016: PeerJ
G Eleftheriou, C Tsabaris, D L Patiris, E G Androulakaki, R Vlastou
A methodology based on γ-spectrometry measurements of untreated coastal water samples is proposed for the direct estimation of coastal residence time of submarine discharged groundwater. The method was applied to a submarine spring at Stoupa Bay covering all seasons. The estimated residence time exhibited an annual mean of 4.6±1.7 d. An additional measurement using the in situ underwater γ-spectrometry technique was performed, in the same site. The in situ method yielded a value of 2.8±0.2 d that was found consistent with the corresponding value derived using the developed lab-based method (3...
December 18, 2016: Applied Radiation and Isotopes
Elena I Kompantseva, Ilya V Kublanov, Anna A Perevalova, Nikolay A Chernyh, Stepan V Toshchakov, Yuriy V Litti, Alexey N Antipov, Elizaveta A Bonch-Osmolovskaya, Margarita L Miroshnichenko
A moderately thermophilic, anaerobic bacterium designated as strain KRT was isolated from a shallow water submarine hydrothermal vent (Kunashir Island, Southern Kurils, Russia). Cells of the strain KRT were thin (0.2-0.3 µm), flexible, motile, Gram-negative rods of variable length. Optimal growth conditions: pH 6.6, 55°C, 1-3% (w/v) NaCl. Strain KRT was able to ferment a wide range of proteinaceous substrates, pyruvate, mono-, di- and polysaccharides. The best growth occurred with proteinaceous compounds...
December 16, 2016: International Journal of Systematic and Evolutionary Microbiology
William S D Wilcock, Maya Tolstoy, Felix Waldhauser, Charles Garcia, Yen Joe Tan, DelWayne R Bohnenstiehl, Jacqueline Caplan-Auerbach, Robert P Dziak, Adrien F Arnulf, M Everett Mann
Seismic observations in volcanically active calderas are challenging. A new cabled observatory atop Axial Seamount on the Juan de Fuca ridge allows unprecedented real-time monitoring of a submarine caldera. Beginning on 24 April 2015, the seismic network captured an eruption that culminated in explosive acoustic signals where lava erupted on the seafloor. Extensive seismic activity preceding the eruption shows that inflation is accommodated by the reactivation of an outward-dipping caldera ring fault, with strong tidal triggering indicating a critically stressed system...
December 16, 2016: Science
Rachel M Lance, Henry Warder, Cameron R Dale Bass
The H.L. Hunley was the first submarine to be successful in combat, sinking the Union vessel Housatonic outside Charleston Harbor in 1864 during the Civil War. However, despite marking a milestone in military history, little is known about this vessel or why it sank. One popular theory is the "lucky shot" theory: the hypothesis that small arms fire from the crew of the Housatonic may have sufficiently damaged the submarine to sink it. However, ballistic experiments with cast iron samples, analysis of historical experiments firing Civil War-era projectiles at cast iron samples, and calculation of the tidal currents and sinking trajectory of the submarine indicate that this theory is not likely...
December 2, 2016: Forensic Science International
A Hosseini, I Amundsen, J Brown, M Dowdall, M Karcher, F Kauker, R Schnur
There is increasing concern regarding the issue of dumped nuclear waste in the Arctic Seas and in particular dumped objects with Spent Nuclear Fuel (SNF). Amongst dumped objects in the Arctic, the dumped Russian submarine K-27 has received great attention as it contains two reactors with highly enriched fuel and lies at a depth of about 30 m under water. To address these concerns a health and environmental impact assessment has been undertaken. Marine dispersion of potentially released radionuclides as a consequence of different hypothetical accident scenarios was modelled using the model NAOSIM...
February 2017: Journal of Environmental Radioactivity
E J Davies, P J Brandvik, F Leirvik, R Nepstad
An in situ particle imaging system for measurement of high concentrations of suspended particles ranging from 30μm to several mm in diameter, is presented. The system obtains quasi-silhouettes of particles suspended within an open-path sample volume of up to 5cm in length. Benchmarking against spherical standards and the LISST-100 show good agreement, providing confidence in measurements from the system when extending beyond the size, concentration and particle classification capabilities of the LISST-100...
December 5, 2016: Marine Pollution Bulletin
Martijn Klaver, Steven Carey, Paraskevi Nomikou, Ingrid Smet, Athanasios Godelitsas, Pieter Vroon
This study reports the first detailed geochemical characterization of Kolumbo submarine volcano in order to investigate the role of source heterogeneity in controlling geochemical variability within the Santorini volcanic field in the central Aegean arc. Kolumbo, situated 15 km to the northeast of Santorini, last erupted in 1650 AD and is thus closely associated with the Santorini volcanic system in space and time. Samples taken by remotely-operated vehicle that were analyzed for major element, trace element and Sr-Nd-Hf-Pb isotope composition include the 1650 AD and underlying K2 rhyolitic, enclave-bearing pumices that are nearly identical in composition (73 wt...
August 2016: Geochemistry, Geophysics, Geosystems: G³
Julia Farkas, Dag Altin, Karen M Hammer, Kaja C Hellstrøm, Andy M Booth, Bjørn Henrik Hansen
Submarine tailing disposal (STD) of mining waste is practiced as an alternative to land fill disposal in several countries. Knowledge regarding the environmental implications of STD on fjord and other marine ecosystems, including the pelagic environment, is scarce. In this study, we characterised the particle shape, size and metal content of the fine-grained fraction of tailings (FGT) from a Norwegian marble processing plant and investigated their acute toxicity and impact on feeding rate in adult Calanus finmarchicus...
February 2017: Chemosphere
Jarrod J Scott, Brian T Glazer, David Emerson
Thirty kilometers south of the island of Hawai'i lies the Lō'ihi Seamount, an active submarine volcano that hosts a network of low-temperature hydrothermal vents enriched in ferrous iron that supports extensive microbial mats. These mats, which can be a half a meter deep, are composed of ferric iron bound to organic polymers-the metabolic byproduct of iron-oxidizing Zetaproteobacteria. Though the role of Zetaproteobacteria in mat formation is well established, we have a limited understanding of how differences in diversity are related to mat morphology...
November 21, 2016: Environmental Microbiology
Robert Foster, Alexander Gilerson
A method is developed to determine the underwater polarized light field from above sea surface observations. A hybrid approach combining vector radiative transfer simulations and the Monte Carlo method is used to determine the transfer functions of polarized light for wind-driven ocean surfaces. Transfer functions for surface-reflected skylight and upward transmission of light through the sea surface are presented for many common viewing and solar geometries for clear-sky conditions. Sensitivity of reflection matrices to environmental conditions is examined and can vary up to 50% due to wind speed, 25% due to atmospheric aerosol load, and 10% due to radiometer field-of-view...
November 20, 2016: Applied Optics
P Nomikou, T H Druitt, C Hübscher, T A Mather, M Paulatto, L M Kalnins, K Kelfoun, D Papanikolaou, K Bejelou, D Lampridou, D M Pyle, S Carey, A B Watts, B Weiß, M M Parks
Caldera-forming eruptions of island volcanoes generate tsunamis by the interaction of different eruptive phenomena with the sea. Such tsunamis are a major hazard, but forward models of their impacts are limited by poor understanding of source mechanisms. The caldera-forming eruption of Santorini in the Late Bronze Age is known to have been tsunamigenic, and caldera collapse has been proposed as a mechanism. Here, we present bathymetric and seismic evidence showing that the caldera was not open to the sea during the main phase of the eruption, but was flooded once the eruption had finished...
November 8, 2016: Nature Communications
K Yin, Y X Song, X R Dong, C Wang, J A Duan
Reported here is the bio-inspired and robust function of underwater superoleophobic, anti-oil metallic surfaces with ultra-broadband enhanced optical absorption obtained through femtosecond laser micromachining. Three distinct surface structures are fabricated using a wide variety of processing parameters. Underwater superoleophobic and anti-oil surfaces containing coral-like microstructures with nanoparticles and mount-like microstructures are achieved. These properties of the as-prepared surfaces exhibit good chemical stability when exposed to various types of oils and when immersed in water with a wide range of pH values...
November 7, 2016: Scientific Reports
Daniel W Amato, James M Bishop, Craig R Glenn, Henrietta Dulai, Celia M Smith
Generally unseen and infrequently measured, submarine groundwater discharge (SGD) can transport potentially large loads of nutrients and other land-based contaminants to coastal ecosystems. To examine this linkage we employed algal bioassays, benthic community analysis, and geochemical methods to examine water quality and community parameters of nearshore reefs adjacent to a variety of potential, land-based nutrient sources on Maui. Three common reef algae, Acanthophora spicifera, Hypnea musciformis, and Ulva spp...
2016: PloS One
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