Anna V. Sharapova

Understanding the rate and direction of pyrogenic succession in arid ecosystems, which depends on many factors, including the intensity of grazing and the frequency of pyrogenic expo-sure, will allow for more accurate predictions of the consequences of fire onplant communities, and will assist with better fire management. We studied the vegetation on 55 sites in and near the “Chernye Zemli” Natural Biosphere Reserve that burned at different times or were not affected by fires over the past 35 years and characterized the changes in vegetation cover associated with the impact of wildfire and grazing. The descriptions were grouped into chronological stages according to the time elapsed since the last fire, or into groups according to the frequency of fires. In pairwise comparison of the projective cover of plant species between chronological stages, it correlated most strongly between successive initial stages (for stages 1 and 2, p = 0.003, r = 0.73; for stages 2 and 3, p < 0.001, r = 0.78). Species with an initially higher projective cover were more likely to grow on plots in the first year after the fire: p < 0.03. Plots with rare and frequent fires had similar projective cover of individual species (r = 0.64, p < 0.001). We conclude that in the course of pyrogenic succession, communities are gradually replaced over at least ten years. At the same time, the composition of a plant community at the initial point of succession depends on the prevalence of species in the community before the fire. No fundamental effect of the frequency of fires on the composition of plant communities has been revealed.

The results of a laboratory experiment modeling the effect of kerosene contamination on the cellulolytic activity of microbiocenosis of the Albic Retisol (Kaluga oblast, Russia) and Arenosol (Kyzylorda oblast, Republic of Kazakhstan) humus horizons are described. Cellulolytic activity is assessed according to the rate of weight loss in linen cloth fragments during the incubation for 0–3, 3–7, and 7–13 months. The intensity of cellulolytic activity in the unpolluted Albic Retisol is higher as compared with the Arenosol, which is determined by low acidity and an elevated content of organic matter and nutrients. The soil pollution with kerosene to 10 g/kg causes a reversible change in cellulolytic activity of both Albic Retisol and Arenosol (Aridic). A high load of kerosene (≥25 g/kg) inhibits cellulolytic activity in both soils over 13 months of observation.

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.

Significant environmental impacts of mining activities connected with high-sulfur materials result from the production of acid mine drainage and potentially toxic elements, which easily migrate to adjacent ecosystems due to the typical absence of vegetation on spoil heaps and toeslope talus mantle. In this paper, we present the results of the first comprehensive study of the ecosystems affected by acidic and metal-enriched (Al, Ca, Co, Cu, Fe, Mg, Mn, Ni, and Zn) mine drainage conducted at spoil heaps and adjacent talus mantle under semihumid climate conditions within the Moscow Brown Coal Basin (Central Russian Upland, Tula Region, Russia). A total of 162 samples were collected, including 98 soil samples, 42 surface water samples, and 22 plant samples (aerial tissues of birch). Coal talus mantle materials of Regosols were characterized by the increased concentration of water-soluble Ca, K, Mg, and S, and all mobile fractions of Al, Co, S, and Zn. The chemical composition of birch samples within the zones affected by acid mine drainage differed insignificantly from those in the unpolluted ecosystems with black soils, due to the high tolerance of birch to such conditions. Differences between the affected and undisturbed sites in terms of the chemical composition decreased in the following order: waters > soils > plants. The geochemical characterization of plants and soils in coal mining areas is essential for the mitigation of negative consequences of mining activities.

In arid lands of Central Kazakhstan, fires commonly occur due to both man-made (e.g. space rocket launches) and natural factors. Remote sensing is the best method to identify burned landscapes and to assess their long-term dynamics. In this paper, we assessed total areas and seasonal features of fires using Landsat 8 OLI data of high spatial and temporal resolution, corrected for atmospheric effects. We defined data requirements, considered various spectral indices, and evaluated their suitability for automated delineation of burned areas. Spectral indices included special burn indices (NBRT, MIRBI, NBR, NBR2, BAI) and vegetation indices (MSAVI, MSAVI2, MTVI2, GEMI3) that allowed us to determine the boundaries and severity of fires indirectly based on the state of vegetation. Our study showed that burned areas were most accurately identified using indices of NBR2 (normalized burn ratio 2) and MSAVI2 (modified soil adjusted vegetation index 2). They were extracted using image segmentation and natural breaks classification methods. We have assessed MSAVI2 and NBR2 segmentation results with machine learning metrics, i.e. for Soyuz drop zone (landing area of rocket stages) precision of NBR segmentation equaled 99.5%, recall − 99.5%, accuracy − 98.5%. For Proton drop zone NBR segmentation precision equaled 99.3%, recall − 99.7%, accuracy − 99.4%. MSAVI2 results are less accurate. The accuracy of segmentation significantly depended on the vegetation state which was predetermined by the frequency and severity of previous fires within certain territory.

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Maximum permissible concentrations for chemical elements in soils (MPCs) of Russia, Germany, Canada, the Netherlands and the USA are compared. In Russia, general sanitary, water-transferred and translocation MPCs are created; in Germany, general sanitary and translocation, and in the Netherlands, the USA and Canada, general sanitary. It is found that the Russian MPCs for total contents of chemical elements are adequate for Mn and V, American, for Co, Cu, and Pb; Dutch, for Pb and Zn; Canadian, for Ba, Co, Ni, Pb, V, and Zn, and German, for Cr, Ni, and Pb by taking into account the typical levels of elements in the background soils across the world. The methodologically closest Russian and Dutch standard rates of total contents of chemical elements are compared in this paper with the typical levels for background Retisols gleic, Phaeozems, and Chernozems in the center of Western Siberia. It is established that use of the Dutch MPCs for the soils under study gives fewer cases of false Pb pollution, but in all the soils under consideration the Dutch MPCs for Ba is exceeded. False pollution by total Zn is observed in the top-soil; by Cr, Cu and V, in subsoil horizons of Retisols gleic as well as by Cr, Ni and V, in most samples of Phaeozems and Chernozems. It is concluded that for the soils under consideration the utilization of Russian MPCs gives fewer cases of false pollution by V. But in the background Retisols gleic, Russian MPCs for Mn and Pb accumulated in the biogeochemical barrier in the top-soil horizons are exceeded. Russian MPCs for metal mobile fraction are the most correct for Co, Cr, Cu, Ni and Pb. The MPCs for mobile fraction of biogenic Mn and Zn are underestimated. Background levels (mg/kg in subindex) of total concentration (mobile fraction extracted by acetate-ammonium buffer) are proposed for Ba_404–515, Co_{12–19(0.001–0.23)}, Cr_{143–188(0.001–0.72)}, Cu_{32–41(0.01–0.72)}, Mn_{423–874(0.09–64)}, Ni_{30–62(0.003–1.3)}, Pb_{18–27(0.003–0.87)}, V_112–170 иZn_{55–104(0.004–0.42)} in Retisols gleic on Tobol Upland, Phaeozems on Ishym Upland, and Chernozems in the Trans-Ural region.

В Российской Федерации наиболее часто эксплуатируются два типа ракет-носителей – "Союз" (средний класс) и "Протон" (тяжелый класс). Воздействие ракет-носителей на окружающую среду оказывается как на наземные экосистемы (в районах падения отделяющихся частей ракет-носителей), так и на различные слои атмосферы по трассе их выведения. Наибольшее воздействие наблюдается в районах падения первой ступени ракет-носителей, которое в разной степени проявляется в виде механических нарушений, пирогенной и термической трансформации, химического загрязнения экосистем. Сравнительный анализ влияния пусков ракет-носителей на экосистемы районов падения второй ступени не выявил специфических особенностей воздействия ракет-носителей различных типов. Основной экологической проблемой в этих районах является загрязнение экосистем фрагментами упавших ступеней.