Cold-seep carbonates of the Laptev Sea continental slope: Constraints from fluid sources and environment of formation

This study presents results of the petrographic, mineralogical, stable isotopes of oxygen and carbon, and trace element investigation of authigenic carbonates collected at newly discovered active cold seeps on the Laptev Sea continental slope at ∼300 m water depth. These carbonates are mainly represented by Mg-calcite with MgCO3 content from 9.1 mol% to 14.0 mol%. The low δ13C values of carbonates ranging from −50.6 ‰ to −32.4 ‰ (V-PDB) indicate that they were formed from anaerobic oxidation of biogenic methane and minor participation of other carbon sources. The difference between measured (from 4.7 ‰ to 5.5 ‰) and calculated (4.0 ‰) δ18Ocarb values might be inherited from fluids enriched in 18O due to dissociation of gas hydrates, which could be the source of methane. The carbonates exhibit weak enrichment in Co, moderate and strong enrichments in As, Mo, and Sb, and strong enrichment in U. Interestingly, As, Sb, and Co correlate with the pyrite content. This indicates that authigenic iron sulfides promote the immobilization of these redox-sensitive elements in seep sediments. The (Mo/U)EF values and anomalies of concentration of Mo and U probably indicate variations in the redox conditions during carbonate formation due to episodically seepage activity changes. Ascending methane-bearing fluids were the main contributor to the enrichment of cold-seep carbonates in As, Mo, Sb, and U at the Laptev Sea continental slope. However additional input from the particulate shuttle process can not be ruled out

Calculation of the weight coefficients of the criteria of the spatial factor and their interrelations with the investment objectives of the purchase of land plots

The article presents the results of the distribution of criteria according to investment objectives, which can serve as the basis for developing a mathematical model for assessing the investment attractiveness of land plots. Existing methods for assessing investment attractiveness were analyzed and a new assessment system was compiled. The criteria were ordered by calculating the weights using the T. Saaty Analytic Hierarchy Process, and the interrelations between the criteria and investment objectives were visualized using a graph. The classification and graph given in the study are able not only to determine the relationship between investment objectives and criteria, but also subsequently to form approaches to assessing the quality of the proposed classification

ПОКАЗАТЕЛИ СВОБОДНОГО МЕТИОНИНА ПЛАЗМЫ КРОВИ У ЧЕЛОВЕКА ПРИ ОСТРОЙ НОРМОБАРИЧЕСКОЙ ГИПОКСИИ

Healthy volunteers participating in the experiment with acute normobaric hypoxia (9% O2, 25 min) showed significant decrease of plasma free methionine in the recovery period at the 15th minute after hypoxia. We assume that displayed changes were caused by de-inhibition of key methionine and glutathione metabolism enzymes, and subsequent compensation of depleted glutathione reserves.Нами было обнаружено достоверное снижение показателей свободного метионина плазмы крови у здоровых добровольцев на 15-ой минуте восстановительного периода после острой выраженной нормобарической гипоксии (9% O2, 25 мин). Мы предполагаем, что наблюдаемая динамика метионина вызвана де-ингибированием ключевых ферментов метаболизма метионина и глутатиона, и компенсацией возникшего в гипоксии дефицита глутатиона

Magma Fracking Beneath Active Volcanoes Based on Seismic Data and Hydrothermal Activity Observations

Active volcanoes are associated with microearthquake (MEQ) hypocenters that form plane-oriented cluster distributions. These are faults delineating a magma injection system of dykes and sills. The Frac-Digger program was used to track fracking faults in the Kamchatka active volcanic belt and fore-arc region of Russia. In the case of magma laterally injected from volcanoes into adjacent structures, high-temperature hydrothermal systems arise, for example at Mutnovsky and Koryaksky volcanoes. Thermal features adjacent to these active volcanoes respond to magma injection events by degassing CO2 and by transient temperature changes. Geysers created by CO2-gaslift activity in silicic volcanism areas also flag magma and CO2 recharge and redistributions, for example at the Uzon-Geyserny, Kamchatka, Russia and Yellowstone, USA magma hydrothermal systems. Seismogenic faults in the Kamchatka fore-arc region are indicators of geofluid fracking; those faults can be traced down to 250 km depth, which is within the subduction slab below primary magma sources

The Seismo-Performer: A Novel Machine Learning Approach for General and Efficient Seismic Phase Recognition from Local Earthquakes in Real Time

When recording seismic ground motion in multiple sites using independent recording stations one needs to recognize the presence of the same parts of seismic waves arriving at these stations. This problem is known in seismology as seismic phase picking. It is challenging to automate the accurate picking of seismic phases to the level of human capabilities. By solving this problem, it would be possible to automate routine processing in real time on any local network. A new machine learning approach was developed to classify seismic phases from local earthquakes. The resulting model is based on spectrograms and utilizes the transformer architecture with a self-attention mechanism and without any convolution blocks. The model is general for various local networks and has only 57 k learning parameters. To assess the generalization property, two new datasets were developed, containing local earthquake data collected from two different regions using a wide variety of seismic instruments. The data were not involved in the training process for any model to estimate the generalization property. The new model exhibits the best classification and computation performance results on its pre-trained weights compared with baseline models from related work. The model code is available online and is ready for day-to-day real-time processing on conventional seismic equipment without graphics processing units

Calculation of the weight coefficients of the criteria of the spatial factor and their interrelations with the investment objectives of the purchase of land plots

The article presents the results of the distribution of criteria according to investment objectives, which can serve as the basis for developing a mathematical model for assessing the investment attractiveness of land plots. Existing methods for assessing investment attractiveness were analyzed and a new assessment system was compiled. The criteria were ordered by calculating the weights using the T. Saaty Analytic Hierarchy Process, and the interrelations between the criteria and investment objectives were visualized using a graph. The classification and graph given in the study are able not only to determine the relationship between investment objectives and criteria, but also subsequently to form approaches to assessing the quality of the proposed classification

ORGANIC CARBON IN SURFACE SEDIMENTS OF LAPTEV SEA AND EAST SIBERIAN SEA: OBSERVATION OF PYROLYSIS DATA

Ongoing global warming accelerates release of relict terrigenous organic carbon from permafrost onto the Arctic shelf waters. When transported in the land-sea system, it can further be accumulated in bottom sediments in the shelf or deep-sea zone and undergo degradation and remineralization, which leads to critical environmental consequences. This study aims at assessing the sources and degradation degree of terrigenous organic matter in the surface sediments of the Eastern Arctic seas. Within this study, marine bottom sediments taken from the surface horizon (0–10 cm) were investigated. Sampling was carried out during the 2011–2019 marine research expeditions. Lateral consistency of hydrogen index values in modern marine sediments on the Eastern Arctic shelf (mainly in the Laptev Sea) is associated with the great contribution of heterogeneous biolabile terrestrial organic matter, in contrast to other Arctic waters, where growing hydrogen index values are associated with the consistently growing contribution of autochthonous organic matter with increasing distance from the coast. While considering the δ13C and HI/OI correlation, there are also significant deviations from the linear dependence which usually indicates a conservative marine geochemical regime. Sediments of the Buor-Khaya Bay are characterized by an increased HI/OI values in contrast to the deep-water sediments of the continental slope which shows lower hydrogen content and a higher proportion of oxygen-containing compounds, indicating a strong transformation of organic matter. These findings confirm a key role of terrigenous supply in specific biogeochemical conditions in the studied area and reveal that geochemical indicators of immature organic matter sources in the Eastern Arctic seas should be interpreted differently from other Arctic continental margins

Rapid identification of fungal laccases/oxidases with different pH-optimum

During the last decade the search for novel biotechnologically valuable laccases/oxidases with a high redox potential and concomitant activity under neutral-alkaline conditions is an attractive and at the same time complicated task due to their rare occurrence in nature. By means of the modified micromethod based on the chromogenic reaction with indicator substrates the successful identification of laccases/oxidases with different pH-optimum was carried out during submerged cultivation of 71 fungal strains of different taxonomic groups. Based on more sensitivity (detected laccase activity can be 4–6 time less as compared with the usual spectrophotometric assay of laccase activity), good productivity (measurements of numerous samples at once in small total volume – up to 150 μL), economy and rapidity, the presented modification of chromogenic reaction can be applied for identification of trace amount of laccase/oxidase activity in biological liquids, to determine the chemoselectivity of induced laccase/oxidase isoforms with respect to pH-value of medium, and to monitor the dynamics of expression of alkaliphilic and acidophilic laccases/oxidases during submerged cultivation of fungi