Role of Methane Cycling in Organic Matter Turnover in Different Types of Lakes

The rates of microbiological processes in CH₄ cycling and organic matter destruction in the bottom sediment and water of different types of lakes in the Upper Volga basin and Baltic countries are determined. The rates of CH₄ removal from silts and the peculiarities of its distribution in water mass as a function of the lake productivity and the character of water mixing in it are studied. The role of processes in CH₄ cycling in destruction is shown to increase with increasing lake productivity.     

Microbiological Processes in the Gor'kovskoe Reservoir

The abundance of various groups of bacteria and the rate of microbiological processes of organic decay and methane cycle in the water and soils of the Gor'kovskoe Reservoir are determined, and the ecological characterization of its river reach is presented. The autochthonous and allochthonous impact on the bacterial community of the reservoir was found to be tolerable; however, some restricted areas were revealed, where the ecosystem is strongly affected by domestic and industrial wastewater, and where the abundance and activity of anaerobic methane-producing and sulfate-reducing soil bacteria increase.     

Methanogenesis and organic matter destruction in bottom sediments of technogenic water bodies

Traits have been revealed in the microbial processes of methane formation and organic matter destruction in bottom sediments of technogenic water bodies, in which at the abundance of C_org compounds, including toxic, dissolved oxygen deficiency, and low redox potential, organic matter decay in sediments is mostly anaerobic with the predominance of methanogenesis and sulfate reduction. Data on major microbial processes are used to calculate the total sludge destruction; it is maximal in the sediments of low-toxicity technogenic water bodies; organic matter destruction in them is mostly due to methanogenesis; it is minimal in high-toxicity water bodies, the share of sulfate reduction in them increases, and that of methanogenesis decreases.     

Experiment in evaluating methane emissions in water bodies of urbanized territories in the Rybinsk Reservoir basin

Quantitative estimation of methane emission processes was carried out for the first time at some water bodies in the Rybinsk Reservoir basin, including those in urbanized territories. It is shown to vary in differet areas within the limits <1–600 ml CH₄/(m² day), attaining its maximum in heavily polluted areas.     

Methane and its transformation processes in water of some tributaries of the Rybinsk Reservoir

Concentration of dissolved methane was determined in the water of some tributaries of the Rybinsk Reservoir subject to different anthropogenic impact; the features of its distribution and the extent of transformations in summer are shown. Its concentration in water of the mouth areas varies within the limits of 2.2 to 280 μl CH₄/l; the rate of methane oxidation is 0.01–230 μl CH₄/(l day). Methanogenesis processes with a rate of 15–28 μl CH₄/(l day) were recorded in surface waters of heavily polluted rivers. A correlation was found to exist between the characteristics of methane cycle and the ecological conditions of the water body.     

The environmental conditions of the sheksna reservoir: Assessment based on microbiological investigations

The results of integrated microbiological studies of the Sheksna Reservoir are presented. The environmental conditions of its water and soil, which are exposed to diverse anthropogenic impact, are assessed. Parts of the reservoir with persistent anthropogenic pollution, which are environmentally unfavorable in terms of the state of silt microflora, are recognized.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 70–78.Original Russian Text Copyright © 2005 by Dzyuban.     

Methane and the Microbiological Processes of Its Transformations in the Water of the Upper Volga Reservoirs

Specific features of CH₄ distribution and the extent of its transformations in the water of reservoirs in the Upper Volga basin are considered. Methanogenesis was detected in water at some stations. The quantitative characteristics of CH₄ and methane oxidation are shown to correlate with the environmental conditions of the reservoir.     

Bacteriobenthos of the Upper Volga Reservoirs as a Characteristic of Their Environmental State

Data of long-term microbiological studies of bottom deposits in the Upper Volga reservoirs and their tributaries are given. Specific features in variations in the structural and functional characteristics of bactriobenthos in individual areas are established depending on a complex of physicochemical characteristics of water and soil and the environmental state of each water body as a whole.     

Specific Features of Humic Substances Oxidation in Surface Waters in the Presence of Glucose

Experiments were conducted to study the microbial co-oxidation of naturally structured humic substances in different water bodies at different glucose concentrations. At low buffer capacity of aquatic ecosystems, the initial stages of the process are shown to be accompanied by a considerable increase in the medium acidity, a decrease in its alkalinity, and accumulation of colored intermediate products of bacterial and enzymatic synthesis. It is found that the co-metabolism processes with highly labile compounds either do not play any significant role in the trophodynamics of aquatic ecosystems (<10% of the original humic material is co-oxidized) or are not detected, notwithstanding the sufficient sensitivity of the analytical techniques involved. The low degree of co-oxidation (or its virtual absence) are found to be attributable to the masking effect of intermediate products.