At present the study of ecological specifics of microbial community in urban soils of the city of Astrakhan is quite urgent. This research enables to characterize the participation of microorganisms in ecological functions of urban soils, as well as to develop the technology for indicating urban pollution. The aim of the given work is to study microbial indices for soils of the urban territory of Astrakhan for bio-remediation and reclamation of disturbed and contaminated soils. The objects were soils sampled in different administrative districts of the city. The soils of Baer’s mounds (brown arid) and island Gorodskoy (alluvial) were also studied. The methods of fluorescent microscopy and inoculation of solid medium were used. The main microbiological indices were investigated, such as the number of prokaryotes and algae, the main ecological and trophic groups of microorganisms, and their quantity ratios. Sanitary-epidemiological indication of urban soils was done. Their state is estimated as satisfactory according to coli titer and index enterococci. The results of the work show that in alluvial soils of the island Gorodskoy prokaryotes predominate in spring, and algae – in autumn. In brown arid soils of Baer’s mounds the processes of organic matter mineralizing are more intensive. It is revealed that free-living nitrogen fixers locate in contaminated alkaline soils. Sulphate-reducing bacteria display activity in urban soils; ammonifying bacteria have high activity in the samples of natural soils and konstruktozems. It is proposed to use as indicators the number of soil algae and diazotroph-bacteria.
Keywords: bio-remediation, reclamation, urban soils, microorganisms, bio-objects as indicators, ecological state, indices.
