RESUMEN
The soil response to a jet-fuel contamination is uncertain. In this article, original data on the influence of a jet-fuel spillage on the topsoil properties are presented. The data set is obtained during a one-year long pot and field experiments with Dystric Arenosols, Fibric Histosols and Albic Luvisols. Kerosene loads were 1, 5, 10, 25 and 100 g/kg. The data set includes information about temporal changes in kerosene concentration; physicochemical properties, such as ÑÐ, moisture, cation exchange capacity, content of soil organic matter, available P and K, exchangeable NH4 +, and water-soluble NO3 -; and biological properties, such as biological consumption of oxygen, and cellulolytic activity. Also, we provide sequencing data on variable regions of 16S ribosomal RNA of microbial communities from the respective soil samples.
RESUMEN
The article presents protocols for determining the biological activity of kerosene-contaminated soils in terms of two indicators, i.e. cellulolytic activity and biological consumption of oxygen. A method for determining the cellulolytic activity of soils is based on measuring the rate of cellulose decomposition in situ. Model test objects (linen fragments 10 × 20 cm weighing 4-6 g) were put in the root layer of soil. A month later, the linen was removed from soil and its weight loss was measured. Cellulolytic activity was estimated by the weight loss of readily hydrolysable organic matter (RHOM) per day (mg/g RHOM per day). The method for determining the biological consumption of oxygen of water was adapted for soils. The indicator characterizes the ability of microorganisms to oxidize organic substances using oxygen for 5 days. The analytic procedure includes taking a soil sample, preparing the suspension (the ratio of soil to distilled water is at least 1:10) and after 5 days measuring the concentration of unspent dissolved oxygen using the oxygen meter. The proposed methods give reproducible and reliable results on the biochemical activity of soil microorganisms in a wide range of soils, e.g. Retisols, Arenosols and Histosols, including those under hydrocarbon pollution.
RESUMEN
One of the most important challenges for soil science is to determine the limits for the sustainable functioning of contaminated ecosystems. The response of soil microbiomes to kerosene pollution is still poorly understood. Here, we model the impact of kerosene leakage on the composition of the topsoil microbiome in pot and field experiments with different loads of added kerosene (loads up to 100 g/kg; retention time up to 360 days). At four time points we measured kerosene concentration and sequenced variable regions of 16S ribosomal RNA in the microbial communities. Mainly alkaline Dystric Arenosols with low content of available phosphorus and soil organic matter had an increased fraction of Actinobacteriota, Firmicutes, Nitrospirota, Planctomycetota, and, to a lesser extent, Acidobacteriota and Verrucomicobacteriota. In contrast, in highly acidic Fibric Histosols, rich in soil organic matter and available phosphorus, the fraction of Acidobacteriota was higher, while the fraction of Actinobacteriota was lower. Albic Luvisols occupied an intermediate position in terms of both physicochemical properties and microbiome composition. The microbiomes of different soils show similar response to equal kerosene loads. In highly contaminated soils, the proportion of anaerobic bacteria-metabolizing hydrocarbons increased, whereas the proportion of aerobic bacteria decreased. During the field experiment, the soil microbiome recovered much faster than in the pot experiments, possibly due to migration of microorganisms from the polluted area. The microbial community of Fibric Histosols recovered in 6 months after kerosene had been loaded, while microbiomes of Dystric Arenosols and Albic Luvisols did not restore even after a year.
RESUMEN
The present study is the field experiment on kerosene pollution impact on southern taiga plant communities. Experimental sites were located in a mixed forest, a deciduous forest, a sedge fen and a wet meadow within the Amur Region of the Russian Far East. Kerosene loads from 1 to 500 g/kg of soil were applied to 50 × 50 cm plots in three replications and their effects on number of species and projective cover of ground vegetation were analysed in 1.5 months and 1 year after exposure. Statistical analyses of data included Student's t-test, Friedman ANOVA and correlation coefficient (r). Phylogenetic analysis was carried out for herbaceous plants on experimental plots. The highest susceptibility to kerosene pollution was found in the mixed forest, where the edificator species (Pteridium aquilinum subsp. pinetorum) was significantly suppressed by the kerosene load of only 1 g/kg of soil. Wetland communities regenerated faster than ground vegetation of forests, especially, in tests with high (>25 g/kg) kerosene loads. The wet meadow community was the most resistant to kerosene pollution, i.e., despite significant decreases in projective cover and number of species after exposure to kerosene loads of 5 and 25 g/kg in the first season, it had the highest regeneration success in the next season. In our study, the kerosene load of 25 g/kg of soil was the threshold level of pollution, above which there were significant structural changes in the studied plant communities. Depending on their abilities to resist kerosene pollution and to regenerate in the next year, dominant species of the studied plant communities were arranged in the following ascending order: Pteridium aquilinum ssp. pinetorum, Convallaria keiskei < Carex cespitosa, Calamagrostis purpurea < Lespedeza bicolor < Vaccinium uliginosum.
