The Effects of Low-Intensity Ultrasound on Toxigenic Cyanobacteria

Doklady Earth Sciences - For the first time, experiments were performed using an ad hoc laboratory setup to study the mechanisms of the effects of low-intensity ultrasound on toxigenic...     

Peculiarities of evaporation regime of Lake Ladoga

The evaporation regime of Lake Ladoga is specified using the renewed meteorological data. The traditional approach is supplemented with a new method of estimating the impact of shallow-water zones on the evaporation intensification worked out by G.N. Panin. The obtained results corroborate that the level of precipitation minus evaporation varies in different zones of the lake that can influence the water mass redistribution in the lake in certain seasons.     

AN EXPERIMENT IN MAPPING THE DISTRIBUTION OF THE STEPPE MARMOT USING AERIAL PHOTOGRAPHS

A method for mapping the distribution of a common steppe mammal, the steppe marmot, is described, based on the interpretation of air photos of its life activities (i.e., burrows). Air photos at 1:30,000 scale are used in the compilation of a map of the density of marmot burrows, which permits close and more efficient investigation of the spatial correspondence of marmot habitats and natural conditions and facilitates the selection of routes and areas of sampling in advance of marmot population counts. Translated by Kurt E. Engelmann, Seattle, WA 98195 from: Vestnik Moskovskogo Universiteta, geografiya, 1989, No. 3, pp. 94–99.     

Searching for the host galaxy of GRB 920925C

GRB 920925C is probably the first cosmic gamma-ray burst with an optical afterglow detected from archival data. We present the results of our observations with the Shajn mirror telescope of the Crimean Astrophysical Observatory aimed at searching for the host galaxy at the afterglow location; we have determined the boundaries of distances to the possible host galaxy.     

Study of changes in the physiological state of cyanobacteria caused by weak ultrasonic treatment

The effect of weak ultrasonic radiation with a frequency of 60 kHz on photosynthetic activity of living cells of cyanobacteria was studied using microspectrometric methods for the first time. An inhibitory effect on the physiological state of separate cells and the whole culture was demonstrated. A high efficiency of the method developed by the authors of this article for determination of the viability of cyanobacterial cultures in vivo for the purpose of operational environmental monitoring of the results of weak external influences was demonstrated.

     

The nonstationary and nonlinear character of Caspian Sea level variations

A stochastic model of level variations in a drainless water body is considered. The model accounts for the nonstationary character of sea level under stationary climate. It is shown that in the case of the Caspian Sea, the range from ?29 to ?26 m BS corresponds to a relative stability of the level because of the greatest gentleness of the shores and shelf slope in combination with the maximal water outflow into Kara-Bogaz-Gol Gulf.     

Chudsko-Pskovskii Lake Complex: Monitoring and modeling phosphorus regime

The existing system for state monitoring of surface waters in the Russian part of the Chudsko-Pskovskii Lake Complex and its catchment is assessed. The ways for the improvement of the monitoring system are outlined. The phosphorus load onto the Chudsko-Pskovskii Lake Complex from the Russian territory is estimated. A balance model is used to calculate the dynamics of mean annual concentrations of total phosphorus in the northern and southern parts of the water body in 1990–2003. The possible use of simplest models for the assessment of the external phosphorus load onto the water body with the existing point and nonpoint sources of phosphorus taken into account is assessed.