The effectiveness of different bioremediation methods (biostimulation, bioaugmentation, the sorption-biological method) for the restoration of soil contaminated with petroleum products in the Russian Subarctic has been studied. The object of the study includes soil contaminated for 20 years with petroleum products. By laboratory experiment, we established five types of microfungi that most intensively decompose petroleum hydrocarbons: Penicillium canescens st. 1, Penicillium simplicissimum st. 1, Penicillum commune, Penicillium ochrochloron, and Penicillium restrictum. One day after the start of the experiment, 6 to 18% of the hydrocarbons decomposed: at 3 days, this was 16 to 49%; at 7 days, 40 to 73%; and at 10 days, 71 to 87%. Penicillium commune exhibited the greatest degrading activity throughout the experiment. For soils of light granulometric composition with a low content of organic matter, a more effective method of bioremediation is sorption-biological treatment using peat or granulated activated carbon: the content of hydrocarbons decreased by an average of 65%, which is 2.5 times more effective than without treatment. The sorbent not only binds hydrocarbons and their toxic metabolites but is also a carrier for hydrocarbon-oxidizing microorganisms and prevents nutrient leaching from the soil. High efficiency was noted due to the biostimulation of the native hydrocarbon-oxidizing microfungi and bacteria by mineral fertilizers and liming. An increase in the number of microfungi, bacteria and dehydrogenase activity indicate the presence of a certain microbial potential of the soil and the ability of the hydrocarbons to produce biochemical oxidation. The use of the considered methods of bioremediation will improve the ecological state of the contaminated area and further the gradual restoration of biodiversity.

Rhodiola rosea (L.) is a valuable source of nutrients. Nutrients have adaptogenic, immunostimulating, nootropic, anti-inflammatory and anti-cancer properties. Natural deep eutectic solvents (NADES) consisting of choline chloride and malonic, malic, tartaric or citric acids have been first used to extract biologically active substances from R. rosea. The total content of polyphenols has been determined by the Folin–Ciocalteu method for all extracts. Antioxidant activity has been determined by the phosphomolybdate method, and antiradical activity has been determined by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method. Rosavin concentration has been determined by high-performance liquid chromatography (HPLC). Extraction kinetics has been evaluated regarding the effectiveness of NADES with each other and with reference solvents (water and 50% ethanol) has been made. Extraction conditions have been optimized according to the Box–Behnken design of the experiment. The optimal parameters of the extraction process have been established. The antibacterial activity of NADES-based extracts against bacterial cultures of Micrococcus luteus, Pseudomonas fluorescens, and Bacillus subtilis has been studied.

The relevance of the Arctic regions’ study is rapidly increasing due to the sensitive response of fragile ecosystems to climate change and anthropogenic pressure. The microbiome is an important component that determines the soils’ functioning and an indicator of changes occurring in ecosystems. Rybachy Peninsula is the northernmost part of the continental European Russia and is almost completely surrounded by Barents Sea water. For the first time, the microbial communities of the Entic Podzol, Albic Podzol, Rheic Histosol and Folic Histosol as well as anthropogenically disturbed soils (chemical pollution and human impact, growing crops) on the Rybachy Peninsula were characterized using plating and fluorescence microscopy methods, in parallel with the enzymatic activity of soils. The amount and structure of soil microbial biomass, such as the total biomass of fungi and prokaryote, the length and diameter of fungal and actinomycete mycelium, the proportion of spores and mycelium in the fungal biomass, the number of spores and prokaryotic cells, the proportion of small and large fungal spores and their morphology were determined. In the soils of the peninsula, the fungal biomass varied from 0.121 to 0.669 mg/g soil. The biomass of prokaryotes in soils ranged from 9.22 to 55.45 μg/g of soil. Fungi predominated, the proportion of which in the total microbial biomass varied from 78.5 to 97.7%. The number of culturable microfungi ranged from 0.53 to 13.93 × 10³ CFU/g in the topsoil horizons, with a maximum in Entic Podzol and Albic Podzol soils and a minimum in anthropogenically disturbed soil. The number of culturable copiotrophic bacteria varied from 41.8 × 10³ cells/g in a cryogenic spot to 5551.3 × 10³ cells /g in anthropogenically disturbed soils. The number of culturable oligotrophic bacteria ranged from 77.9 to 12,059.6 × 10³ cells/g. Changes in natural soils because of anthropogenic impact and a change in vegetation types have led to a change in the structure of the community of soil microorganisms. Investigated tundra soils had high enzymatic activity in native and anthropogenic conditions. The β-glucosidase and urease activity were comparable or even higher than in the soils of more southern natural zone, and the activity of dehydrogenase was 2–5 times lower. Thus, despite the subarctic climatic conditions, local soils have a significant biological activity upon which the productivity of ecosystems largely depends. The soils of the Rybachy Peninsula have a powerful enzyme pool due to the high adaptive potential of soil microorganisms to the extreme conditions of the Arctic, which allows them to perform their functions even under conditions of anthropogenic interference.

An ecological and microbiological study of the soil of the Beringovsky settlement in Chukotka Autonomous okrug has been performed. It has been found that the operation of the nearby coal storage area and household activities led to severe disturbance of natural tundra gley soils (Histic Cryosols). In the disturbed soil, the pH values increased up to the neutral or slightly alkaline reaction; the contents of exchangeable hydrogen, nitrogen, carbon of organic compounds, and available potassium and sodium decreased, and the background concentrations of heavy metals (Ni, Cu, Mn, Fe, and Zn) increased; for Cu and Zn, they exceeded the maximum permissible concentrations (MPCs) established for these elements. The enzymatic activity in the organic horizon of the studied soil determined by the colorimetric method decreases. The number of cultivated saprotrophic and oligotrophic bacteria in the upper horizon of the disturbed soil is 2–10 times higher than in the background soil, while the number of microscopic fungi—psychrophiles and mesophiles—is 38 and 9 times lower. The disturbed soil of the settlement contains thermophilic fungi belonging to conditionally pathogenic species and bacteria of the Escherichia coli group. An increase in the diversity of micromycetes in the soil of the settlement and changes in the structure of the fungal community have been revealed. In the disturbed soil of the settlement, 45 species of algae and cyanobacteria have been identified. In general, the diversity of microphototrophs in the disturbed soil of the settlement is significantly higher than that in the background native tundra gley soil, mainly at the expense of yellow-green and diatomaceous algae and cyanobacteria.

The efficiency of the sorption–biological method for treatment of oil-polluted coastal substrates (soil and sand) of the Barents Sea under low temperature (10 °C) using the active hydrocarbon-oxidizing bacterial strain Rhodococcus erythropolis HO-KS22 was assessed in the laboratory. The highest rate of hydrocarbon degradation was in sand polluted with a low-density oil emulsion and in soil polluted with a medium-density oil emulsion. Sorption–biological treatment increased the rate of hydrocarbon degradation in sand by 3–4 times during the first month and enhanced the overall efficiency by 20% over a three-month period. The use of sorbents (granular activated carbon, thermally activated vermiculite and peat) both in sand and soil prevents secondary pollution of coastal ecosystems, since it significantly reduces the hydrocarbons’ desorption and their leaching by water. Rhodococcus erythropolis HO-KS22, in combination with sorbents, can be applied during the biological remediation of coastal sandy substrates following the initial removal of emergency oil spills. However, for biological treatment of oil-polluted soils of the Barents Sea coast, further selection of active strains of hydrocarbon-oxidizing bacteria resistant to low pH values and temperatures typical for this region is necessary. The use of microbiological preparations without taking into account the soil and climatic factors of the region may be ineffective, which will increase the cost of remediation of the territory without significantly improving its condition.

Представлена новая концепция биоремедиации антропогенных водных объектов, а также очистки сточных карьерных вод методом фитоэкстракции и фитотрансформации в арктических условиях, основанная на технологии преобразования техногенных водоёмов в природоподобные болотные экосистемы. Технология базируется на создании фитоматов, позволяющих в ускоренном режиме формировать растительные блоки трёх разных типов: для задернения песчано-гравийных участков (откосы фильтрационных дамб и др.), для создания растительных сообществ на мелководных участках водоёмов и для создания сообществ на глубоководных участках. При формировании фитоматов используются два субстрата-почвозаменителя и регионально-оптимизированный ассортимент из 24 видов растений. Определение содержания нитрат-ионов в некоторых растениях биоплато (Comarumpalustre L., Eryophorum angus-tifolium Honck., Salixphylicifolia L.) показало их преимущественное накопление в корнях. Предлагаемый подход к формированию природоподобных болотных экосистем для очистки сточных карьерных вод впервые осуществлён в практике действующих горнорудных предприятий в экстремальных условиях Субарктики. Внедрение данной технологии позволило на 22% повысить эффективность очистки сточных карьерных вод от минеральных соединений азота, не требуя при этом затрат энергии, химикатов и дефицитных в регионе почвенных...