A new version of a conceptual climate model of river runoff was used to calculate daily and monthly hydrographs for the Lena R. basin with the use of MERRA reanalysis data and data on runoff from R-ArcticNet archive over a 32-year period (1980–2011). The optimization of model parameters and corrections to precipitation allowed the authors to obtain a good quality of the calculated runoff hydrographs and to reveal a trend in the long-term runoff dynamics over the historical period since 1985 to 2011. The period 1985–2011 shows an abrupt increase in the surface air temperature, an increase in precipitation in the Arctic region since the mid-1980s, in particular, in the Lena River basin. The climate changes have led to changes in the hydrological regime of the river basin, and the question of assessing the long-term dynamics of water discharges over this period, in particular, using the conceptual model, gains in importance.

The dependence of the concentrations of cultivated microorganisms and total protein on meteorological parameters (wind direction and speed, solar radiation, temperature, atmospheric pressure, relative and absolute humidity) is studied based on three years measurements. Sampling was carried out at the site of the State Scientific Center of Virology and Biotechnology “Vector” of Rospotrebnadzor, Koltsovo, Novosibirsk region, with simultaneous recording of weather conditions. The concentration of total protein was determined by the fluorescence method of a protein binding reagent, and the concentration of cultivated microorganisms was determined by standard cultural methods. Weather parameters were received from a weather station located near the sampling site. The analysis of the data shows that the concentrations of biological components in aerosol increase with the average temperature, absolute humidity, and illumination during sampling and decrease with an increase in the average relative humidity, wind speed, and atmospheric pressure.

Реализован метод переменной по времени скорости потока для концептуальной модели формирования речного стока с целью улучшения маршрутизации потока в бассейне р. Лены. В отличие от моделей, использующих постоянную скорость, в этом подходе скорость, изменяющаяся во времени, зависит от количества стока, генерируемого в ячейке сетки суши. Для оценки скорости потока в приближении прямоугольного поперечного сечения для речного русла используется уравнение Маннинга. Численные эксперименты с постоянной и переменной скоростями потока позволили сравнить модельный сток с наблюдаемыми суточными гидрографами на стоковых станциях Кюсюр, Табага и Верхоянский Перевоз. Приведена оценка теплового потока в бассейне р. Лены на гидропосту Кюсюр за период 2002-2011 гг. A time-varying flow velocity method for a conceptual model of river flow generation is implemented with the aim of improving flow routing in the Lena river basin. In contrast to constant velocity models, this approach uses a time-varying velocity which depends on the amount of flow generated in a land grid cell. The Manning equation is used to estimate flow velocity in the rectangular cross-sectional approximation for the river channel. Numerical experiments with constant and variable flow velocities made it possible to compare the model flow with the observed daily hydrographs at the runoff stations of Kyusyur, Tabaga, and Verkhoyanskiy Perevoz. The work provides an estimate of the heat flow from the Lena river basin to Kyusyur gauging station for 2002-2011.

— The new coronavirus pneumonia has rapidly spread around the world. The World Health Organization emphasized that the SARS-CoV-2 coronavirus spreads mainly between people who are in close contact with each other, as well as in the case of touching contaminated surfaces followed by touching the eyes, nose, or mouth without first cleaning the hands. Possible permanent sources of the spread of the virus can be gathering of patients in hospitals in the case of noncompliance with the requirements for organizing the functioning of a hospital. Meteorological conditions can be a key factor influencing the spread of the virus in the case of an accidental release of virus-containing aerosol from such a hospital. Simulations are carried out with modern methods for solving a system of differential equations of the atmospheric boundary layer, which are adapted to describe the distribution of harmful atmospheric impurities over a real complex terrain considering urban buildings of various heights, forests, reservoirs, changing meteorological conditions, and many other factors.

Оценка теплового потока с бассейна реки Лена1 Институт вычислительной математики и математической геофизики СО РАН, г.Новосибирск, Российская Федерация 2 Федеральное бюджетное учреждение науки

In the latest version of the climatic model of river flow formation, water transport along the river network to the mouth was carried out for each section of the Lena River and its tributaries at its constant rate. This paper presents two approaches to routing surface runoff with time-varying flow rates. The use of these approaches may allow the model to represent not only average multi-year flow rates, but also the ability to simulate floods and short-term fluctuations in river flow. Two numerical experiments were conducted: simulations of river flow with constant and variable velocities.

— The article presents long-term data of abundance and biomass of bacterial biofilms forming on Phragmites australis (Cav . ), one of widespread species of the Rybinsk Reservoir higher aquatic plants. Daily production of bacteria and phytoepiphyton is reported, as well as the rate of bacterial degradation of organic matter. The numbers of microorganisms belonging to various physiological groups were determined, and their relative abundance in the total bacterioepiphyton was determined. Epiphyton taxonomic diversity was determined using molecular genetic techniques. Bacteria of the genus Cellvibrio (class Gammaproteobacteria ) were found to be responsible for cellulose degradation.

The total abundance of bacteria, the number of saprophytic, oligotrophic, and sulfate-reducing microorganisms, the shapes of bacterial cells, the primary and bacterial production, the destruction of organic matter, and the rate of sulfate reduction were studied in small Karelian lakes during the stagnation period. It has been shown that the uneven vertical distribution of light, temperature, oxygen, and hydrogen sulfide creates ecological niches for the development of many various groups of microorganisms. In most lakes, the minimum abundance of microorganisms was found in the surface water layer, while its maximum was in the near-bottom layers. The trophic status of a water body has a great influence on the formation and function of microbial communities. Autochthonic organic matter in the closed forest lakes under study (the local term is "lamba") was formed due to phytoplankton photosynthesis, but bacterial production exceeded primary production in the hypolimnion of eutrophic lakes. The content of hydrogen sulfide, the abundance of sulfate-reducing bacteria, and the rate of sulfate reduction were maximal in the bottom sediments of eutrophic lambas.

The development of bacteria, phytoplankton, zooplankton, and microperiphytic organisms in artificial ecosystems, such as microcosms with aquatic plants, depressing algae (water soldier Stratiotes aloides L.), and plants not possessing a significant impact on them (arrowhead Sagittaria sagittifolia L.), was evaluated. It was shown that the zooplankton biomass did not decrease among water soldiers, despite the fact that the concentration of phytoplankton pigments was 2–3 times lower. The number of euplanktonic Cladocera has not declined, and the number of littoral and phytophilic Cladocera increased, but the number of Diaptomidae was lower. It is assumed that a large zooplankton biomass was produced by the use of bacteria and protozoa as an additional power supply to the algae. The share of zooplanktonic species consuming bacteria increased in microcosms with arrowhead. The number of predators increased and trophic relations between zooplankton and microperiphyton became closer in experimental systems with the plants of both species.

Numerical simulation of hydrological and hydro-chemical regimes is performed using the mathematical model of water quality, developed at Lavrentyev Institute of Hydrodynamics SB RAS. This method is based on the one-dimensional Saint-Venant equations and the transfer equation of heat, oxygen and other impurities. The paper presents examples of numerical simulation.

The atmospheric air quality is determined by the concentrations of some gaseous pollutants and mass concentrations of aerosol particles of different sizes. A wide range of atmospheric pollutants in both gaseous and aerosol phases was studied in the vicinity of Gelendzhik in July 2009, simultaneously at several land sites, in the water area of the bay, and at altitudes of up to 2200m. No such complex experiments were carried out in that region before. The following characteristics of the atmospheric aerosol (3 nm–32 μm in size) were studied: elemental composition of particles (23 chemical elements) and concentrations of polyaromatic hydrocarbons (14 compounds), unsaturated hydrocarbons, total protein, biotoxins, and culturable microorganisms. The concentration fields of different air pollutants and the complex air pollution index were constructed using mathematical models of pollutant propagation and data on the hydrometeorological conditions during the period of measurements. The sources of aerosols in the region were detected from the study of the chemical composition of airborne particles. The results allowed us to estimate air pollutants and to calculate the complex air pollution index for the Gelendzhik area. The daily average concentrations of all the pollutants were compared to the daily average maximum permissible concentrations. All these concentrations were less than daily average maximum permissible concentrations. The complex air pollution index did not exceed 1. Hence, the air in the vicinity of Gelendzhik did not contain any significant pollutants in the period under study.

The dynamics of structural and functional characteristics of microbial communities over vegetation period in zone of higher aquatic plants thickets of the Rybinsk reservoir has been studied. It was established that diversity of morphological forms and bacteria abundance in this zone is higher than in open sections. Genetic diversity of bacterial communities is represented by two main phyla: Cyanobacteria and Proteobacteria. Significant fluctuations of hydrochemical regime and production-destruction processes in the reservoir occur over active vegetation and decaying of plants.

Aquatic plants have a major influence upon other aquatic organisms, by altering both water chemistry and spatial structure of the habitat in shallow water bodies. Some of them, such as Stratiotes aloides L., may suppress algal growth. But how aquatic plants would ultimately influence the heterotrophic community and the aquatic ecosystem as a whole is far from clear. Our microcosm-based study demonstrated that even a modest density of S. aloides caused a decline in phytoplankton chlorophyll concentration and periphytic algae abundance, including cyanobacteria, whereas diatoms appeared to be immune to the plant influence. Photosynthetic rate remained unaltered despite decreased chlorophyll concentration. While bacterial counts remained largely unchanged, more bacteria were observed forming microcolonies as well as associating with particulate organic matter. Numbers of periphytic heterotrophic organisms did not differ significantly between the planted and plant-free control microcosms. Zooplankton diversity increased and cladocerans assumed a more prominent position within the microcosms with macrophytes. We assume that the presence of plant’s leads to increased importance of bacteria and protists in the functioning of the food webs. Therefore, decreasing of algal abundance does not involve reducing the number of heterotrophic planktonic and periphytic organisms.

We discuss the results from the analysis of the hydrological input data for a model of Siberian river runoff for the 21st century. The INM, CRNM, GFDL, MIROC5, and HadGEM model calculations according to the RCP 8.5 scenario of the IPCC CMIP5 Project were used for the analysis. The calculations show a positive centennial trend for all the models. These data were used for the calculations of Siberian river discharge to the Arctic Ocean. The river runoff calculations in accordance with the data also indicate a positive trend, though with a different runoff magnitude.

The propagation of freshwater anomalies from Siberian rivers in the Arctic Ocean in the 21st century has been simulated using a model developed in Institute of Computational Mathematics and Mathematical Geophysics, Russian Academy of Sciences (ICMMG RAS), based on the output of the ICM RAS model and scenario RPC 8.5, project CMIP-5 IPCC. River runoff has been calculated using a linear reservoir model with 1/3-degree resolution, including nine major drainage basins in Siberia.

A method for searching several hidden point sources of admixtures in the atmosphere is proposed. The sources can have different emission rates and be located at different points in space. The method is based on using the conjugate equation of turbulent diffusion. The effect of the number of test admixture concentration measurement points and inevitable errors in concentration measurements on the accuracy of the sought sources’ parameters is analyzed. Results of test calculations are presented.

Исследовано влияние погруженного гидрофита Ceratophyllum demersum L. на численность и биомассу Daphnia longispina O.F. Muller. В эксперименте показано, что гидрохимические характеристики среды в зарослях исследуемого растения не выходят за пределы толерантности D. longispina. В присутствии роголистника в воде увеличивались концентрации фосфатов, хлорофилла а и биомасса бактерий. Непосредственно среди растений происходило подавление развития дафний, обусловленное ограничением движения рачков. В среде, содержащей только метаболиты Ceratophyllum demersum, обилие Daphnia longispina возрастало вследствие обогащения кормовой базы.