Seasonal hydrological and hydrochemical surveys in the Voevoda Bay (Amur Bay, Japan Sea)

Hydrological and hydrochemical surveys were conducted in the Voevoda Bay in May, August, and October, 2011 and February, 2012, in total 140 stations. Free water exchange of the bay with the Amur Bay is observed, with exception of its inner bights Kruglaya and Melkovodnaya. The water exchange is maintained by anticyclonic circulation with the inflow along the southern coast and outflow along the northern coast of the Voyevoda Bay. However, the opposite cyclonic circulation is observed in the Melkovodanaya Bight because of its coastal line patterns and fresh water discharge by the river. Dissolved oxygen content and partial pressure of CO2 in the bay waters are determined mostly by intensive processes of production and destruction of organic matter. There are three main groups of primary producers there, as diatom algae, sea grass Zostera marina , and periphyton. Specific chemical regime is formed in the Melkovodnaya Bight, in particular in winter when primary production depends on the ice cover and is driven by variations of photosynthetically active radiation passed through the ice. Seasonal variability of production-destruction processes intensity is discussed on the data of chemical parameters changes

Predicting Ship Trajectory Based on Neural Networks Using AIS Data

To create an autonomously moving vessel, it is necessary to know exactly how to determine the current coordinates of the vessel in the selected coordinate system, determine the actual trajectory of the vessel, estimate the motion trend to predict the current coordinates, and calculate the course correction to return to the line of the specified path. The navigational and hydrographic conditions of navigation on each section of the route determine the requirements for the accuracy of observations and the time spent on locating the vessel. The problem of predicting the trajectory of the vessel’s motion in automatic mode is especially important for river vessels or river-sea vessels, predicting the trajectory of the route sections during the maneuvering of the vessel. At the moment, one of the most accurate ways of determining the coordinates of the vessel is by reading the satellite signal. However, when a vessel is near hydraulic structures, problems may arise connected with obtaining a satellite signal due to interference and, therefore, the error in measuring the coordinates of the vessel increases. The likelihood of collisions and various kinds of incidents increases. In such cases, it is possible to correct the trajectory of the movement using an autonomous navigation system. In this work, opportunities of the possible application of artificial neural networks to create such a corrective system using only the coordinates of the ship’s position are discussed. It was found that this is possible on sections of the route where the ship does not maneuver

Seasonal Hypoxia of Amursky Bay in the Japan Sea: Formation and Destruction

Based on detailed hydrological and hydrochemical surveys carried out in each of the four seasons of 2008, Amursky Bay in the north west quadrant of the Japan Sea was found to experience seasonal hypoxia. The primary process of hypoxia formation is a microbiological degradation of the ¡§excess¡¨ amount of diatoms under rather low photosynthetic active radiation in bottom layer and weak water dynamics. The microbiological decay of dead diatoms under light deficient conditions intensively consumes dissolved oxygen and produces phosphates, ammonium, silicates, and dissolved inorganic carbon. Existence of a phytoplankton ¡§excess¡¨ is caused by phytoplankton bloom resulting from nutrient pulses into Amursky Bay. There are two main sources of these nutrients: the waste waters of Vladivostok city and discharge from Razdolnaya River. The river delivers more than two times the amount of nutrients than the waste waters of Vladivostok. It is suggested that the phytoplankton ¡§excess¡¨ might be caused by an enhanced supply of nutrients delivered into the surface layer resulting from the increased discharge of the river on a short time scale. Our data suggest that hypoxia is seasonal, with a peak at the end of summer. The upwelling of the Japan Sea water in the beginning of the fall season and its advection across the shelf is the primary process by which the hypoxia is destroyed. During the winter, strong vertical mixing due to termohaline convection makes the water column uniform and brings more oxygen into the water along with high primary production under the ice. Thus, during the winter season, the ecosystem of Amursky Bay recovers completely

Bacteria primarily metabolize at the active layer/permafrost border in the peat core from a permafrost region in western Siberia

The microbial activity in the soils of the permafrost-affected zones is assumed to be one of the major factors that modify the organic carbon and nitrogen cycle under current climate change. In contrast to the extensive research centered on bacterial abundance, diversity, and metabolic activity in permanently and seasonally frozen mineral soils from high latitudes, frozen peat (organic) environments remain poorly characterized in terms of the physiological diversity and metabolic potential of bacteria. The evolution of soil heterotroph microbial number and metabolic activity across the “seasonally thawed (active)—permanently frozen layer” boundary was studied on 100-cm-thick cores from frozen peat mounds located in the discontinuous permafrost zone in western Siberia. There was a systematic decrease of metabolic activity in the upper 40 cm of the peat core from the surface layers of the mosses and lichens towards the beginning of the frozen horizon, followed by an abrupt increase in bacterial metabolism exactly at the border between the thawed layer and the permafrost table. The aerobic viable cell count and total bacterial number from the active layer were similar to those from the permafrost peat layer. The highest metabolic activity was observed at the beginning of the frozen peat layer and might correspond to the highest availability of amino substrates, which were depleted in the active layer but preserved in the deeper frozen horizons. The enhanced microbial activity at the frozen peat-active layer boundary in western Siberia may persist for another 50–100 years based on the current rate of increase in active layer thickness

Bacteria primarily metabolize at the active layer/permafrost border in the peat core from a permafrost region in western Siberia

The microbial activity in the soils of the permafrost-affected zones is assumed to be one of the major factors that modify the organic carbon and nitrogen cycle under current climate change. In contrast to the extensive research centered on bacterial abundance, diversity, and metabolic activity in permanently and seasonally frozen mineral soils from high latitudes, frozen peat (organic) environments remain poorly characterized in terms of the physiological diversity and metabolic potential of bacteria. The evolution of soil heterotroph microbial number and metabolic activity across the “seasonally thawed (active)—permanently frozen layer” boundary was studied on 100-cm-thick cores from frozen peat mounds located in the discontinuous permafrost zone in western Siberia. There was a systematic decrease of metabolic activity in the upper 40 cm of the peat core from the surface layers of the mosses and lichens towards the beginning of the frozen horizon, followed by an abrupt increase in bacterial metabolism exactly at the border between the thawed layer and the permafrost table. The aerobic viable cell count and total bacterial number from the active layer were similar to those from the permafrost peat layer. The highest metabolic activity was observed at the beginning of the frozen peat layer and might correspond to the highest availability of amino substrates, which were depleted in the active layer but preserved in the deeper frozen horizons. The enhanced microbial activity at the frozen peat-active layer boundary in western Siberia may persist for another 50–100 years based on the current rate of increase in active layer thickness

Cardiovascular Efficacy and Safety of Bococizumab in High-Risk Patients

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