Features of the functioning of microbiocenoses of cultivated soddy-podzolic soil under conditions of oil pollution

Saint-Petersburg Scientific Research Centre for Ecological Safety – a separate structural subdivision of the Federal State Budgetary Institution of Science “Saint Petersburg Federal Research Center of the Russian Academy of Sciences”, 197110 Saint Petersburg, Russia

^* Corresponding author: chugunova54@gmail.com

Abstract

The study goal was to explore the characteristics of the functioning of microbiocenoses of well-cultivated soddy-podzolic soil, contaminated with doses of oil under the conditions of a field experiment. The level of initial pollution with petroleum products was in percentage: 0, 0.5, 1.0, 1.5 and 3.0. Sampling for laboratory research was carried out 14 days, 6 and 18 months after the oil spill. To assess the activity of the microbiota under conditions of soil self-purification from oil pollution, integral indicators were chosen. 1. The amount of carbon dioxide released from the soil, the so-called basal respiration, corresponds to the complete destruction of oil (to CO2 and H2O) by soil microorganisms. 2. The medium-regulating (regulatory) microorganisms’ activity, which is defined as the biological response of the soil to a disruption of chemical balance, was assessed by the quantity of CO2 release after 1% glucose addition. The oil products content was defined in real time mode. Soil microbiocenoses were highly perseverant to the inhibitory effects of oil pollution. Disturbances in the normal functioning of the microbiota as a result of oil pollution were non-critical and reversible. Half-year after the oil spill, at all levels of pollution, there was a sharp increase in basal respiration. Its level exceeded the respiration rate of clean soil several-fold. This indicated the high biochemical activity of hydrocarbon-oxidizing resident microbiota and as a result an active self-cleaning of soil from oil pollution. The negative dynamics of the petroleum products content proved the microbial character of the oil destruction processes in the soil.