1928 research outputs found
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Development strategy of Gazpromneft Sakhalin in current economic realities
Full text linkA presentation that was held on the webinar: Potential of O&G Projects of the Far East in New Economic Realities in May 2020 by Vostock Capita
Features of sea ice motion observed with ice buoys from the central Arctic Ocean to Fram Strait
Full text linkUsing six ice-tethered buoys deployed in 2012, we analyzed sea ice motion in the central Arctic Ocean and Fram Strait. The two-hourly buoy-derived ice velocities had a magnitude range of 0.01–0.80 m·s−1, although ice velocities within the Arctic Basin were generally less than 0.4 m·s−1. Complex Fourier transformation showed that the amplitudes of the sea ice velocities had a non-symmetric inertial oscillation. These inertial oscillations were characterized by a strong peak at a frequency of approximately −2 cycle·d−1 on the Fourier velocity spectrum. Wind was a main driving force for ice motion, characterized by a linear relationship between ice velocity and 10-m wind speed. Typically, the ice velocity was about 1.4% of the 10-m wind speed. Our analysis of ice velocity and skin temperature showed that ice velocity increased by nearly 2% with each 10 ℃ increase in skin temperature. This was likely related to weakened ice strength under increasing temperature. The ice-wind turning angle was also correlated with 10-m wind speed and skin temperature. When the wind speed was less than 12 m·s−1 or skin temperature was less than −30 ℃, the ice-wind turning angle decreased with either increasing wind speed or skin temperature. Clearly, sea ice drift in the central Arctic Ocean and Fram Strait is dependent upon seasonal changes in both temperature and wind speed
Laboratory experimental study of water drag force exerted on ridge keel
Full text linkWith the diminishing Arctic sea ice, the dynamic energy-exchange process between sea ice and ocean gains in importance. Concerning how the ice bottom topography affects the drift of sea ice, it is unclear how the ridge–keel-drag force exerted by seawater changes the momentum balance of sea ice. We thus conducted laboratory experiments to investigate how the local drag coefficient of the ridge keel depends on keel shape and on the relative velocity of ice with respect to seawater. A dimensional analysis is used to obtain the relationship between the local drag coefficient Cr, the Reynolds number Re, the dimensionless keel depth h0, and the keel slope angle φ. The results indicate that the local drag coefficient Cr is only relevant to Re when Re < 4000 and the flow is in the laminar regime. With increasing Re, Cr depends on h0 and φ, which are independent variables, as the flow transitions to the turbulent regime. The parameterization formulas for Cr are also provided
The growth of the Rhodococcus sp. on diesel fuel under the effect of heavy metals and different concentrations of zinc
Full text linkCo-contamination of diesel fuel and heavy metals can be challenging for microbial remediation due to the complex composition of the fuel and the inhibitory effect of heavy metals. There is an urgent need to study this interaction to improve the pollutant removal efficiency in the Polar Regions. The growth of an Antarctic bacterium, Rhodococcus sp. was studied by comparing the growth at the logarithmic phase under the effect of selected heavy metals (Pb, Cr, As, Cd, Cu, Zn, Ni, Hg and Co). The selected heavy metals inhibited the growth of the Rhodococcus sp. on diesel fuel in an order from highest to lowest of: Hg > Zn > Cd > Cu > Co > Ni > As >Pb> Cr. Growth on diesel fuel co-contaminated with Hg and Zn were 2.95% and 5.71%, respectively compared to the no-metal control. A further experiment with various Zn concentrations was conducted. The specific growth rate of Rhodococcus sp. co-contaminated with different concentrations of Zn showed a correlation coefficient (r) of 0.916, and was modelled with an exponential decay model. Additional investigation is needed to determine the effect of low concentration of Zn on hydrocarbon degradation. It is important to understand the relationships between microbes, hydrocarbons and heavy metals, especially in the Polar Regions because this interaction might be promising in treating hydrocarbon-polluted sites containing heavy metals. The data and results also provide baseline tools of bioremediation processes at low temperatures and the knowledge of the ecological roles of Rhodococcus sp. in Antarctica
Genome of a thermophilic bacterium Geobacillus sp. TFV3 from Deception Island, Antarctica
Full text linkThermophilic microorganisms have always been an important part of the ecosystem, particularly in a hot environment, as they play a key role in nutrient recycling at high temperatures where most microorganisms cannot cope. While most of the thermophiles are archaea, thermophiles can also be found among some species of bacteria. These bacteria are very useful in the fundamental study of heat adaptation, and they are also important as potential sources of thermostable enzymes and metabolites. Recently, we have isolated a Gram-positive thermophilic bacterium, Geobacillus sp. TFV3 from a volcanic soil sample from Deception Island, Antarctica. This project was undertaken to analyze the genes of this thermophilic Antarctic bacterium and to determine the presence of thermal-stress adaptation proteins in its genome. The genome of Geobacillus sp. TFV3 was first purified, sequenced, assembled, and annotated. The complete genome was found to harbor genes encoding for useful thermal-stress adaptation proteins. The majority of these proteins were categorized under the family of molecular chaperone and heat shock protein. This genomic information could eventually provide insights on how the bacterium adapts itself towards high growth temperatures
Hybrid energy module for remote environmental observations, experiments, and communications
Full text linkIncreased concerns about climate change have led to a significant expansion of monitoring, observational, and experimental sites in remote areas of the world. Meanwhile, advances in technology and availability of low-power equipment have allowed increasingly sophisticated measurements with a wide variety of instruments. However, the deployment and use of these technologies in remote locations is often restricted not only by harsh environmental conditions, but also by the availability of electrical power and communication options. In some cases, research stations and military installations can provide power for scientific equipment, data acquisition, storage, and transmission. Clustering of research sites near existing infrastructure has had the unintended consequence of limiting a spatial understanding of large geographic regions. Fortunately, the modern market offers many power and communication solutions, but most of them are oriented toward large industrial applications. Use of those solutions to power a research site is limited because of their cost and need for significant modification for the specific research purposes. Each study has its own unique power requirements and needs for proper instrumentation. A power and communication solution for a vast majority of implementations with or without modification would be of considerable benefit. This article describes design of a universal, scalable hybrid energy module for the Next-Generation Ecosystem Experiments Arctic project (https://ngee-arctic.ornl.gov/). Two modules were built, and the authors describe their implementation and findings over a 2-year period at a remote field site on the Seward Peninsula in western Alaska, USA
First description of scleractinian corals from the Santa Marta and Snow Hill Island (Gamma Member) formations, Upper Cretaceous, James Ross Island, Antarctica
Full text linkAntarctic corals are known from the Upper Cretaceous Santa Marta Formation (Santonian–early Campanian) and Gamma Member (late Campanian) of Snow Hill Island Formation (late Campanian–early Maastrichtian) but they have not so far been taxonomically described. We describe three corals taxa based on 29 specimens collected in 2007 and 2016 on James Ross Island (northeast of the Antarctic Peninsula). They represent the first formal record of scleractinian corals from the Santa Marta Formation, identified as Caryophylliidae indet. and Gamma Member of Snow Hill Island Formation, identified as ?Astreopora sp. and Fungiacyathus deltoidophorus. The family Caryophylliidae and the genus Astreopora were not restricted to the Weddellian Biogeographic Province but the species Fungiacyathus deltoidophorus was endemic to Antarctica during the Cretaceous. The genus Fungiacyathus and the family Caryophylliidae thrive in Antarctica until the present day. Fungiacyathus occurred in shallower environments during the late Campanian than today. No specimens related to Astreopora have yet to be found in Antarctica after the late Campanian. This can be explained by the capacity of Fungiacyathus and Caryophyllidae to endure cold waters, since they are asymbiotic corals. The symbiotic ?Astreopora sp., due to its sensitivity to low temperatures, became extinct in this continent as soon as the Antarctic waters began to cool, around the Campanian/Maastrichtian. The presence of ?Astreopora sp. in Gamma Member of Snow Hill Island Formation may represents the first occurrence of this genus in Antarctica and the oldest record of this genus in the Southern Hemisphere
Atmospheric responses over Asia to sea ice loss in the Barents and Kara seas in mid–late winter and early spring: a perspective revealed from CMIP5 data
Full text linkThis study investigated atmospheric responses in mid–late winter and early spring to sea ice loss in the Barents and Kara seas using regressions of the January–March mean atmosphere on Barents and Kara sea ice area in November and December. Similar atmospheric circulation responses were obtained from reanalysis data and multimodel ensemble results from the Coupled Model Intercomparison Project Phase 5, i.e., sea ice anomalies are the dominant factor driving the overlying atmosphere. The results showed that an Arctic–Asia dipole structure, with opposite anomalies over the mid-latitudes of Asia and over the adjoining Arctic, appears to be the key atmospheric circulation anomaly influencing the East Asian climate in mid–late winter and early spring