scholarly journals A Handheld Sampler for Collecting Organic Samples from Shallow Hydrothermal Vents

2013 ◽  
Vol 30 (8) ◽  
pp. 1951-1958 ◽  
Author(s):  
Shi-Jun Wu ◽  
Can-Jun Yang ◽  
Chen-Tung Arthur Chen
Keyword(s):  
Hydrothermal Vents ◽  
Ambient Pressure ◽  
Machining Accuracy ◽  
Regulation Mechanism ◽  
Filling Rate ◽  
Compact Structure ◽  
Scuba Divers ◽  
Annular Gap ◽  
Gas Tight ◽  
Shallow Hydrothermal Vents

Abstract This study describes a new handheld sampler, specially designed to be deployed by scuba divers, to collect fluid samples from shallow hydrothermal vents. The new sampler utilizes a syringe-like titanium sampling bottle with a regulated filling rate to collect samples. The filling rate regulation mechanism of the new sampler was studied. Through theoretical analysis and simulation, it is found that the filling rate can be regulated by either an orifice or an annular gap on the sampler. Further study indicates that the orifice is superior to the annular gap, since the former has a much lower requirement of machining accuracy. Moreover, the filling rate regulated by the orifice is independent of temperature and ambient pressure. The new sampler also features a compact structure, simple operation, and gas-tight performance. Efforts were made to minimize the organic carbon blank of the sampler by careful selection of the materials that may come into contact with the fluid samples. The sampler has been tested at the shallow hydrothermal vents off northeastern Taiwan. High-purity organic samples were successfully collected.

scholarly journals Fabrication of Micro-Structured Polymer by Micro Injection Molding Based on Precise Micro-Ground Mold Core

Micromachines ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 253 ◽  
Author(s):  
Yanjun Lu ◽  
Fumin Chen ◽  
Xiaoyu Wu ◽  
Chaolan Zhou ◽  
Yan Lou ◽  
...  
Keyword(s):  
Injection Molding ◽  
Mass Production ◽  
Injection Pressure ◽  
Machining Accuracy ◽  
Filling Rate ◽  
Micro Structure ◽  
Micro Injection Molding ◽  
Melt Temperature ◽  
Array Structures ◽  
Micro Structures

Precise micro-grinding machining was proposed to fabricate regular and controllable micro-grooved array structures on the surface of mold cores to realize the mass production and manufacturing of micro-structured polymer components by micro injection molding in this paper. First, the 3D topographies and section profiles of micro-ground mold cores and micro-formed polymers with different micro-structure parameters were presented. Then, the surface roughness of mold cores and polymers were compared. Next, the relationships between machining accuracy of mold core ground by micro-grinding and filling rates of micro-structured polymer formed by micro injection molding were investigated. Finally, the influences of micro injection molding parameters on the filling rate of micro-structures polymer were investigated. It is shown that the micro-structured polymer can be effectively and rapidly fabricated using the proposed method. The experimental results indicate the highest form accuracy of the micro-grooved mold core and the filling rate of micro-structured polymer can reach to 4.05 µm and 99.30%, respectively. It is found that the filling rate of the micro-structured polymer roughly increased with increasing machining accuracy of the mold core. The injection pressure had the greatest influence on the filling rate of the injection formed polymer, while the melt temperature had the least influence.

scholarly journals Effects of pressure on the dynamics of an oligomeric protein from deep-sea hyperthermophile

2015 ◽  
Vol 112 (45) ◽  
pp. 13886-13891 ◽  
Author(s):  
Utsab R. Shrestha ◽  
Debsindhu Bhowmik ◽  
John R. D. Copley ◽  
Madhusudan Tyagi ◽  
Juscelino B. Leão ◽  
...  
Keyword(s):  
Hydrothermal Vents ◽  
Ambient Pressure ◽  
Inorganic Pyrophosphatase ◽  
Relaxation Dynamics ◽  
Egg White Lysozyme ◽  
Protein Energy ◽  
Oligomeric Protein ◽  
Model Protein ◽  
Quasielastic Neutron ◽  
Β Relaxation

Inorganic pyrophosphatase (IPPase) from Thermococcus thioreducens is a large oligomeric protein derived from a hyperthermophilic microorganism that is found near hydrothermal vents deep under the sea, where the pressure is up to 100 MPa (1 kbar). It has attracted great interest in biophysical research because of its high activity under extreme conditions in the seabed. In this study, we use the quasielastic neutron scattering (QENS) technique to investigate the effects of pressure on the conformational flexibility and relaxation dynamics of IPPase over a wide temperature range. The β-relaxation dynamics of proteins was studied in the time ranges from 2 to 25 ps, and from 100 ps to 2 ns, using two spectrometers. Our results indicate that, under a pressure of 100 MPa, close to that of the native environment deep under the sea, IPPase displays much faster relaxation dynamics than a mesophilic model protein, hen egg white lysozyme (HEWL), at all measured temperatures, opposite to what we observed previously under ambient pressure. This contradictory observation provides evidence that the protein energy landscape is distorted by high pressure, which is significantly different for hyperthermophilic (IPPase) and mesophilic (HEWL) proteins. We further derive from our observations a schematic denaturation phase diagram together with energy landscapes for the two very different proteins, which can be used as a general picture to understand the dynamical properties of thermophilic proteins under pressure.

Bacterial and archaeal populations at two shallow hydrothermal vents off Panarea Island (Eolian Islands, Italy)

Extremophiles ◽  
2008 ◽  
Vol 13 (1) ◽  
pp. 199-212 ◽  
Author(s):  
Teresa Luciana Maugeri ◽  
Valeria Lentini ◽  
Concetta Gugliandolo ◽  
Francesco Italiano ◽  
Sylvie Cousin ◽  
...  
Keyword(s):  
Hydrothermal Vents ◽  
Shallow Hydrothermal Vents

scholarly journals Effect of explosive shallow hydrothermal vents on δ13C and growth performance in the seagrass Posidonia oceanica

2010 ◽  
Vol 98 (6) ◽  
pp. 1284-1291 ◽  
Author(s):  
Salvatrice Vizzini ◽  
Agostino Tomasello ◽  
Germana Di Maida ◽  
Maria Pirrotta ◽  
Antonio Mazzola ◽  
...  
Keyword(s):  
Growth Performance ◽  
Hydrothermal Vents ◽  
Posidonia Oceanica ◽  
Shallow Hydrothermal Vents

scholarly journals Synthesis of α-cristobalite-type CO2-SiO2under extreme conditions

2014 ◽  
Vol 70 (a1) ◽  
pp. C753-C753
Author(s):  
Julien Haines ◽  
Mario Santoro ◽  
Federico Gorelli ◽  
Roberto Bini ◽  
Olivier Cambon ◽  
...  
Keyword(s):  
Solid Solution ◽  
Cell Volume ◽  
Unit Cell Volume ◽  
Metastable Phase ◽  
Ambient Pressure ◽  
Small Variation ◽  
Unit Cell ◽  
Extreme Conditions ◽  
Oxygen Sublattice ◽  
Compact Structure

Extreme conditions change the behavior and reactivity of elements and compounds and permit the synthesis of novel materials. In the case of group IV oxides, molecular CO2and a network solid silica, which were considered to be incompatible, are found to react under HP-HT conditions. A crystalline CO2-SiO2solid solution was synthesized from molecular CO2and microporous silicalite SiO2at 16-22 GPa and temperatures above 4000 K in a laser heated diamond anvil cell [1]. Synchrotron X-ray diffraction data show that the crystal adopts a densely packed α-cristobalite structure (space group P41212) with carbon and silicon in 4-fold coordination. This occurs at pressures at which SiO2normally adopts a 6-fold coordinated rutile-type stishovite structure. The P-T conditions used in this study represent a compromise between the respective stabilities of 3- and 4-fold coordination in CO2and 4- and 6-fold coordination in SiO2. This solid solution can be recovered at ambient pressure at which the unit cell volume is 26% lower than that of α-cristobalite SiO2. This is due to the incorporation of much smaller carbon atoms, resulting in the collapse of the oxygen sublattice. The unit cell volume and the different C and Si sites identified in Raman spectroscopy are consistent with a C:Si ratio of 6(1):4(1). The tetragonal c/a ratio increases from 1.283 at 16 GPa to 1.303 at ambient pressure and is lower than that of SiO2due to the more compact structure of the new material and essentially corresponds to that of the dense rutile-type oxygen sublattice. This can explain the small variation in volume observed for this phase corresponding to a bulk modulus of about 240 GPa. Due to the incorporation of silicon atoms, this hard solid based on CO4tetrahedra can be retained as a metastable phase. This strongly modifies standard oxide chemistry and shows that carbon can enter silica giving rise to a new class of hard, light, carbon-rich oxide materials with novel physical properties.

scholarly journals Earthquake and typhoon trigger unprecedented transient shifts in shallow hydrothermal vents biogeochemistry

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Mario Lebrato ◽  
Yiming V. Wang ◽  
Li-Chun Tseng ◽  
Eric P. Achterberg ◽  
Xue-Gang Chen ◽  
...  
Keyword(s):  
Hydrothermal Vents ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Carbonate System ◽  
Sr:Ca Ratios ◽  
Dissolved Heavy Metals ◽  
One Year ◽  
High Level ◽  
Shallow Hydrothermal Vents ◽  
Surrounding Seawater

AbstractShallow hydrothermal vents are of pivotal relevance for ocean biogeochemical cycles, including seawater dissolved heavy metals and trace elements as well as the carbonate system balance. The Kueishan Tao (KST) stratovolcano off Taiwan is associated with numerous hydrothermal vents emitting warm sulfur-rich fluids at so-called White Vents (WV) and Yellow Vent (YV) that impact the surrounding seawater masses and habitats. The morphological and biogeochemical consequences caused by a M5.8 earthquake and a C5 typhoon (“Nepartak”) hitting KST (12th May, and 2nd–10th July, 2016) were studied within a 10-year time series (2009–2018) combining aerial drone imagery, technical diving, and hydrographic surveys. The catastrophic disturbances triggered landslides that reshaped the shoreline, burying the seabed and, as a consequence, native sulfur accretions that were abundant on the seafloor disappeared. A significant reduction in venting activity and fluid flow was observed at the high-temperature YV. Dissolved Inorganic Carbon (DIC) maxima in surrounding seawater reached 3000–5000 µmol kg−1, and Total Alkalinity (TA) drawdowns were below 1500–1000 µmol kg−1 lasting for one year. A strong decrease and, in some cases, depletion of dissolved elements (Cd, Ba, Tl, Pb, Fe, Cu, As) including Mg and Cl in seawater from shallow depths to the open ocean followed the disturbance, with a recovery of Mg and Cl to pre-disturbance concentrations in 2018. The WV and YV benthic megafauna exhibited mixed responses in their skeleton Mg:Ca and Sr:Ca ratios, not always following directions of seawater chemical changes. Over 70% of the organisms increased skeleton Mg:Ca ratio during rising DIC (higher CO2) despite decreasing seawater Mg:Ca ratios showing a high level of resilience. KST benthic organisms have historically co-existed with such events providing them ecological advantages under extreme conditions. The sudden and catastrophic changes observed at the KST site profoundly reshaped biogeochemical processes in shallow and offshore waters for one year, but they remained transient in nature, with a possible recovery of the system within two years.

scholarly journals A Special Issue on Microorganisms from Extreme Environments in Memory of Luigi Michaud (1974–2014)

Diversity ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 2
Author(s):  
Angelina Lo Giudice ◽  
Concetta Gugliandolo
Keyword(s):  
Microbial Diversity ◽  
Hydrothermal Vents ◽  
Extreme Environments ◽  
Research Paper ◽  
Special Issue ◽  
Research Papers ◽  
Biotechnological Potential ◽  
Geothermal Soils ◽  
Extremophilic Microorganisms ◽  
Shallow Hydrothermal Vents

A special issue (SI) titled “Microbial Diversity in Extreme Environments: Implications for Ecological and Applicative Perspectives” has been launched with the aim of showcasing the diversity and biotechnological potential of extremophilic microorganisms. The issue includes 10 research papers and four reviews that mainly address prokaryotes inhabiting hyperarid, hypercold, hyperalkaline and hypersaline (or polyextreme) environments, spanning from deserts to meromictic and glacier lakes around the globe. Thermophilic prokaryotes from shallow hydrothermal vents and Antarctic geothermal soils are also treated. The ecology and biotechnological perspectives of eukaryotes are discussed in two review papers and one research paper. This special issue serves as a memorial to Dr. Luigi Michaud (1974–2014), who dramatically passed away in Antarctica during underwater sampling activities.

A new serial sampler for collecting gas-tight samples from seafloor cold seeps and hydrothermal vents

2020 ◽  
Vol 161 ◽  
pp. 103282 ◽  
Author(s):  
Shuo Wang ◽  
Shijun Wu ◽  
Mengran Du ◽  
Canjun Yang ◽  
Xun Wang
Keyword(s):  
Hydrothermal Vents ◽  
Cold Seeps ◽  
Gas Tight

scholarly journals Novel, Attached, Sulfur-Oxidizing Bacteria at Shallow Hydrothermal Vents Possess Vacuoles Not Involved in Respiratory Nitrate Accumulation

2004 ◽  
Vol 70 (12) ◽  
pp. 7487-7496 ◽  
Author(s):  
Karen M. Kalanetra ◽  
Sherry L. Huston ◽  
Douglas C. Nelson
Keyword(s):  
Hydrothermal Vents ◽  
Repeated Measurements ◽  
Rrna Gene ◽  
Nitrate Accumulation ◽  
Sulfur Bacteria ◽  
Physiological Properties ◽  
Large Central Vacuole ◽  
White Point ◽  
Sulfur Oxidizing ◽  
Shallow Hydrothermal Vents

ABSTRACT Novel, vacuolate sulfur bacteria occur at shallow hydrothermal vents near White Point, Calif. There, these filaments are attached densely to diverse biotic and abiotic substrates and extend one to several centimeters into the surrounding environment, where they are alternately exposed to sulfidic and oxygenated seawater. Characterizations of native filaments collected from this location indicate that these filaments possess novel morphological and physiological properties compared to all other vacuolate bacteria characterized to date. Attached filaments, ranging in diameter from 4 to 100 μm or more, were composed of cylindrical cells, each containing a thin annulus of sulfur globule-filled cytoplasm surrounding a large central vacuole. A near-complete 16S rRNA gene sequence was obtained and confirmed by fluorescent in situ hybridization to be associated only with filaments having a diameter of 10 μm or more. Phylogenetic analysis indicates that these wider, attached filaments form within the gamma proteobacteria a monophyletic group that includes all previously described vacuolate sulfur bacteria (the genera Beggiatoa, Thioploca, and Thiomargarita) and no nonvacuolate genera. However, unlike for all previously described vacuolate bacteria, repeated measurements of cell lysates from samples collected over 2 years indicate that the attached White Point filaments do not store internal nitrate. It is possible that these vacuoles are involved in transient storage of oxygen or contribute to the relative buoyancy of these filaments.

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