Biogeosystem Technique

205-217

Authors: Sergei I. Kolesnikov, Anna A. Kuzina, Kamil Sh. Kazeev, Natal'ya A.Vernigorova, Natal'ya A. Evstegneeva

At the present time soils are exposed to increasing anthropogenic impact. The construction of new resorts, roads, pipelines – all of which can increase the soil pollution with heavy metals and oil. One of the most sensitive and informative indicators of the ecological condition of soils is the determination of the activity of the dehydrogenase. As a result, modeling studies found that pollution of chromium, copper, nickel, lead and oil reduces the dehydrogenase activity in all major soils of the Black Sea coast of the Caucasus: southern chernozem, brown typical, brown leached, brown carbonate, brown forest acidic, brown forest acid podzolized, sod-carbonate typical, sod-carbonate leached soils, zheltozem. As a rule, for all investigated heavy metals and oil was a direct relationship between the content in the soil contaminant and the degree of reduction of the biological indicator. The results indicate that the most significant negative impact has chrome. In terms of the negative impact of the change dehydrogenase activity in the studied soils Black Sea coast heavy metal oxides to form the following generalized sequence: Cr > Cu ≥ Ni ≥ Pb. A comparative evaluation of the stability of the dehydrogenase activity to contamination with heavy metals and oil for the main soils of the Black Sea coast of the Caucasus. Heavy metal pollution is least affected dehydrogenase activity typical sod-carbonate soils. For oil pollution on a particular indicator were more stable brown soil Resistance to the chemical contamination of soil depends on the nature and concentrations of pollutants in the soil, as well as the genetic properties of the soil itself.

229-234

Authors: Evgeny V. Shein, Nadezhda V. Verkhovtseva, Evgeny Yu. Milanovsky, Anna A. Romanycheva

The interaction of microorganisms with mineral part of the soil solid phase determines the number of processes, such as weathering of primary minerals, their destruction or transformation due to the production of organic ligands and acids. The article describes the modification of the surface of the clay minerals kaolinite and montmorillonite by the pure culture of Bacillus circulans, capable of removing silicon and potassium from the minerals. After two months of culturing the bacteria in a clay medium, where the clay minerals were the source of potassium, the surfaces properties (contact angle, surface area) and microaggregate composition of clays were changed. The composition of the microbial community was reconstructed according to the microbial markers (fatty acids and their derivatives—fatty hydroxyacids and aldehydes) that were determined after the acid methanolysis of the samples using the molecular method of gas chromatography−mass-spectrometry. It is shown that the result of adsorption of bacteria and their metabolites and the formation of tightly bound microbial biofilm on the surface of a solid mineral phase was the clay surface hydrophobization. Sorption of bacterial metabolic products on the clay surface causes a decrease in the specific surface area, contact angle and C/N ratio. The formation of stable microaggregates with a diameter of about 30 mkm was noted. The role and importance of microorganisms in the changing mineral surface and in the initial stage of formation of aggregate waterproof structure are highlights.