Effect of rhizospheric oil-degrading bacteria on the biological state of oil-polluted soil
M.S. Tretyakova, L.A. Belovezhets, L.G. Sokolova, S.Yu. Zorina, Yu.A. Markova
Section: Remediation and rehabilitation
Environmental pollution with oil and oil products is a serious issue faced both by Russia and by the whole world. Currently, the use of microbiological preparations, which include indigenous microorganisms adapted to climatic and environmental conditions of a particular region, is an effective way to remediate oil-polluted soils. The use of microorganisms isolated from plant rhizosphere is promising for soil bioremediation due to their high biotechnological potential. The paper presents the results of model experiments on the influence of strains of oil-degrading microorganisms (Rhodococcus erytropolis 108, Acinetobacter guillouiae 112, Acinetobacter guillouiae 114) isolated from wheatgrass rhizosphere and their consortium on the purification of oil-polluted soil. The indicators of soil phytotoxicity, change in its enzymatic and respiratory activity. After 60 days of the experiment, the oil loss in oil-polluted soil with the introduction of the studied strains was shown to increase by 19-24% relative to the control and amount to 62-68% of its initial content. The enzymatic and respiratory activity of the soil increased against the background of oil destruction by the microorganisms. Treatment of oil-polluted soil with the strains of oil-degrading bacteria contributed to an increase in its phytotoxicity in the early stages of radish (Raphanus sativus) ontogeny. This was especially characteristic of the A. guillouiae 112 strain. The soil inoculated with R. erytropolis 108 had the least phytotoxicity throughout the experiment. For the first time, the obtained rhizospheric strains of the genera Rhodococcus and Acinetobacter were shown to accelerate the process of purifying the soil from oil and be able to be used for bioremediation of oil-polluted soils.
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-156-162
Views: 18
Features of transformation of old oil pollution in the soils of the Arctic zone of Yakutia
Yu.S. Glyaznetsova
Section: Chemistry of natural environments and objects
In the Arctic zone of Yakutia, ecological and analytical studies have been carried out to study the chemical composition of the oil-contaminated soils of the tank farm. The row of informative analytical indicators was used to characterize the composition of oil pollution and assess the features of its biodegradation processes in permafrost soils. The features of the chemical composition of oil pollution in soil samples with a long-term contamination are revealed and are taken into account at developing methods for cleaning soils from "old" oil pollution. An experiment on the biological treatment of soils with a biological product based on indigenous hydrocarbon-oxidizing microorganisms isolated from permofrost soils was conducted. The initial oil content was 34594 mg/kg. After 3 months of incubation of a biological product, along with a decrease in the residual oil content, the composition of pollution changed in the direction of increasing the content of resin-asphaltene components and decreasing − hydrocarbons. The proportion of oxygen-containing groups and bonds has significantly increased in the chemical structure of alcohol-benzene resin. In the composition of alkane hydrocarbons, a redistribution is established both within the homologous series and between different rows of homologues. The established increase in the ratio (Pr+Ph) / (nC17+nC18) in the row: oil (as a pollutant) → initial “old” pollution → altered pollution after 3 months of incubation of the biological product, indicates the destruction of n−alkanes nC17 and nC18, which are least resistant to biodegradation, and relative accumulation more stable isoprenoids of pristan and phytane. The degree of destruction of oil pollution reached 56.6%.
Keywords: transformation, old oil pollution, biodegradation, permafrost soils, asphaltenes and resins components
One of the modern requirements of forest management is the conservation of biodiversity by identifying forests with high conservation value (HCV), especially rare ecosystems and habitats (HCV type 3). Based on the systemic and regional approaches, the methodology for determining HCV 3 has been improved and a system has been created in the Kirov region with the distribution of classes and levels. The class of Fir-spruce forests includes two levels – large-fern with the presence of nemoral elements and tall grasses; with the presence of rare and vulnerable species. The class of Pine forests are divided into sphagnum with the presence of rare and vulnerable species, lichen (with steppe elements) and heather. The Forest class with the participation of broad-leaved species has three levels – linden and multi-species forests in the subzones of the middle and southern taiga of the Kirov region, oak forests (including the subzone of mixed forests). The classes of Larch and Black alder forests, Old-aged aspens are not subdivided into levels. The composition of the stand, the age of the prevailing species of the stand, the species composition of the grass-shrub layer, the conservation value and the recommended conservation and forest management regimes each HCV 3 describes; necessary criteria for assessing forest management, monitoring and compliance of forestry activities with international standards are identified. The developed system is not final; it can be supplemented and expanded in connection with newly emerging data. The use of the proposed materials will ensure the conservation of biodiversity of production forests, compliance with the requirements of the National FSC Standard of the Russian Federation for forest management, and positioning of the Kirov region as a supplier of quality wood.
The modern taxonomic and geographical composition, trophic mode and spatial distribution of polychaete worms - one of the most important components of the bottom ecosystems of the Pechora Sea, is studied. This area characterized by the special abiotic conditions, a high level of biological production, a variety of biotopes and numerous populations of rare and protected species.
According to the materials of the last expeditions in the Pechora sea, 198 taxa of polychaete worms were identified: 165 belonging to species, 113 genera, 34 families and 14 orders.
Everywhere the species diversity of polychaetes and stress stability of their populations was high, with the exception of small areas, located near entrance to the Pechora and Khaypudir bays with amount of river runoff. The density of settlements widely varied from 26 to 7144 ind./m2. Density gradients are most pronounced in the south-eastern shallow part of the Pechora Sea and in a lesser extent in the north-western of region. The spatial distribution of polychaete biomass is also heteroge-neous, but varies much less in absolute terms from 0.7 to 387 g/m2.
Four major groups represent the trophic mode of polychaete bioresources. More than half of the total biomass is created by surface detrivorous, a few less than a third - by subsurface detrivorous, 2% - by suspension feeders, and 10% - by carnivorous. The 80% of all polychaetes constituted only by six species, and the most significant of which are Spiochaetopterus typicus and Maldane sarsi.
During the last 70 years the number ratio of species belonging to main biogeographic groups remains stable, although the taxonomic list is constantly increasing. The stable state of the of poly-chaete taxocene, playing the significant role in the bottom ecosystems, assumes the stable state of bot-tom biocenoses of the Pechora Sea in general.
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-208-214
Views: 16
The changes in growth processes of the European grayling from the Timan stream in conditions of non-controlled exploitation
E.I. Boznak, A.B. Zakharov
Section: Population ecology
The work deals with the retrospective analysis of linear growth dynamics for the European grayling in one of the Middle Timan streams (the Vym River, the Northern Dvina basin) under continuous unsustainable exploitation. The European grayling grows relatively fast indicating favorable environmental conditions. In contrast with the data of 1970-1990-ies, the specimens from generations formed in unsustainable fishing years (born in 2003-2012) increase in the segmented body length value (by 15%), absolute increments (by 19%), and specific growth rate (on the second-fourth living year – by 12%). Then, the grow rate slows down. The following five years do not much differ by the considered parameters. The growth slowdown seems to be related to the active commercial catching of quickly-growing fish specimens as they early reach the right size. The accelerated growth processes are accompanied by accelerated sexual development. The grayling normally becomes mature on the fifth-sixth living year (in 1980-1990-ies). From the early 2000-s, we regularly face sexually mature four-year-old (3+) specimens. There are no true correlation between mean annual temperatures and body length of five-to-seven-year-old specimens. The food resources of grayling also hold stable. Thus, the continuous over-exploitation of fish population results in visible changes in population parameters (population decrease, age structure degradation) and invisible aftereffects (growth and sexual maturation acceleration).
Keywords: the European grayling, linear growth, sexual maturation, non-commercial fishing, over-exploitation
The numbers of hydrocarbon-oxidizing and ammonifying microorganisms (psychrophilic and mesophilic) in the soils of the aeration zone and groundwater polluted with petroleum products under application of mineral fertilizers were analyzed. In the soils of the aeration zone, the numbers of aerobic microorganisms increased by 1-2 orders of magnitude, ammonifying ones – up to 107 CFU/g, hydrocarbon oxidizing microorganisms – up to 106 CFU/g, at the same time numbers of psychrophilic microorganisms increased by 13%. In groundwater the numbers of psychrophilic hydrocarbon-oxidizing microorganisms increased from 104 to 107 CFU/g, mesophilic ones from 105 to 107 CFU/g; the numbers of ammonificating microorganisms increased from 104 to 108 CFU/g and from 105 to 107 CFU/g, respectively. The number and variety of protozoa also increased. In the soils only flagellates of Bodo genus were found, their numbers during processing changed from 10-102 cells/g to 103 cells/g; in groundwater from 102–103 cells/ml to 104 cells/ml. The number of ciliata (Ciliata, Uronema genus) in groundwater changed from tens of cells per ml to 102–103 cells/ml. After treatment, ciliata were detected in all water samples, and in addition to Uronema genus ciliata of Colpoda genus were discovered. The biostimulation produced changes in the chemical composition of groundwater (ammonium concentration, permanganate oxidizability of water), that indicated the decomposition of petroleum products and the appearance of easily oxidizable organic substances in water. The concentration of petroleum products in groundwater over the course of 3 years has decreased from 500–120 mg/dm3 to 10–1.5 mg/dm3.
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-149-155
Views: 9
Elimination of fecal indicator bacteria in soils at repeated irrigation with livestock waste
О.E. Chezlova, А.A. Volchak
Section: Social ecology
To determine the survival time of fecal indicator bacteria (coliform bacteria, Escherichia coli and enterococci) in soils, a field experiment was conducted on sod-podzolic gley soil on cohesive sand when disposing of wastewater from livestock farms. During the field season, wastewater was introduced three times by the norms of 90, 180 and 270 m3 / ha. By the end of the vegetation period, the content of coliform bacteria in the soil using the norms of 180 and 270 m3 / ha is 2.17x102 and 2.16x102 CFU / g, respectively; the number of enterococci is 3.94x102 CFU / g and 2.17x102 CFU / g, respectively. To describe the dynamics of the number of microorganisms, a first order approximation was used. During the first irrigation with wastewater, the highest withering rate was observed in E. coli: the extinction constant k was in the range from 0.129 to 0.253 day -1, and the time of a 10-fold reduction in numbers from 17.9 to 10.4 days with irrigation rates of 90 and 180 m3 / ha, respectively. For enterococci, the parameter k ranged from 0.092 to 0.149 day -1, and the time of 90% elimination ranged from 25.1 to 15.4 days with irrigation rates of 90 and 270 m3 / ha, respectively. For coliform bacteria with a watering rate of 90 m3 / ha, k = 0.131 day-1, and the time of 90% elimination is 17.6 days. By the third irrigation with wastewater, the rate of elimination of E. coli, enterococci and coliform bacteria decreased - the constant k decreased by an average of 4.45, 3.79 and 2.12 times, respectively. For an adequate description of the dynamics of indicator bacteria in soils, it is necessary to take into account climatic, soil factors, the amount of wastewater, etc.
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-236-242
Views: 9
Ecological condition of the coast of the Maloe More strait and its influence on pollution of Lake Baikal
I.A. Belozertseva, I.B. Vorobyeva, N.V. Vlasova, D.N. Lopatina, M.S. Yanchuk
Section: Monitoring of natural and anthropogenically disturbed areas
In the winter-spring, in the summer and fall of 2016-2018 complex physiographic researches in east Priolkhonye with sampling of snow, soils and a surface water are conducted. Local pollution of snow and atmospheric air near settlements and camp sites of the coast of the Lake Baikal is revealed. Content of ammonium, phosphates and oil products in snow exceed maximum allowable concentration. Pollution of coastal waters of Small Sea Strait and the Sarma River in a recreational zone is established. Ecological, chemical and physical soil properties of meadow and steppe landscapes of Olkhon district in the territory of the east coast of the Lake Baikal which is most visited by tourists are studied. The explored soils have mainly low-power strong and middle stony profile, light particle size distribution, high content of a humus, mainly neutral and weak alkaline reaction. As a result of the conducted researches it is revealed that soils near tourist tracks are polluted by heavy metals. The ecological condition of soils at the present stage can be characterized as average degree of a disturbance as a result of recreational activity. Geochemical barriers are - organic and alkaline. However owing to light particle size distribution of soils there can be a pollution of waters of a coastal zone of the lake.
Keywords: soils, snow, water, pollution, recreation, Maloe More Strait, Lake Baikal
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-066-074
Views: 10
Influence of microbiological preparations on yield of spring soft wheat
I.U. Ivanova, D.A. Dementiev
Section: Agroecology
Thousands of tons of chemical products are used annually in the world industrial production of agricultural products, both mineral fertilizers and toxic chemicals, aimed at combating diseases, pests and weeds. These chemicals actively influence not only the object of the struggle, but also the soil flora and fauna. The inhabitants of the soil, which loosen the soil, as well as the microorganisms involved in the processes of humification and mineralization of humus, are dying. The vacant ecological niches are occupied by organisms pathogenic for plants. This leads to the need to apply disinfectants and fungicides in even larger quantities.
One way to break this destructive chain is to replace chemical fungicidal drugs with microbiological ones. In these preparations, microorganisms are natural competitors of phytopathogens, which have an antibiotic effect, protecting the cultivated crop from diseases. In addition, these microorganisms are able to assimilate free nitrogen of the air, supplying them with plants and soil, transfer inaccessible phosphorus compounds to plants that are readily available for plants, produce growth stimulants and other biologically active substances that positively affect the growth, development and productivity of the crop. Also, the soil is saturated with microflora useful for the soil and plants.
On the experimental base of the Chuvash Research Institute of Agriculture, the effect of microbiological preparations on biometrics, yield and economic efficiency of cultivation of spring soft wheat varieties Moskovskaya 35 was investigated. The greatest increase in yield on average for 2 years was given by the joint use of preparations based on nitrogen-fixing and phosphate-mobilizing microorganisms - up to 1.5 t / ha. At the same time, the cost of bio-fertilizers amounted to 1.9-5.4% of the total cost structure. The profitability of cultivation increased from 14.4% with the use of only one strain of microorganisms, up to 43.5% with the use of 2 types of microbiological fertilizers, in comparison with the control.
Keywords: microbiological fertilizers, growth stimulants, spring soft wheat, yield
The research deals with theoretical calculation of the maximal growth rate of green halophilic microalga Dunaliella salina in the conditions of natural illumination at South regions of Russia (Sevastopol city as an example). The calculation is based on the concept that microalgae growth rate is defined as the difference between gross productivity and endogenous biomass expenditure rate. Gross productivity is a function of PAR, absorption coefficient and energy utilization efficiency. For maximal productivity calculation it is suggested that all incident of the pond surface light energy is absorbed by microalgae culture. As far as photobiosynthesis efficiency value depends on illuminance in a complex way, we used average value 5.58 %. The rate of endogenous biomass expenditure was determined based on the value of night losses, which for D. salina was about 5 %.Computations showed that for D. salina maximum biomass gain makes 26 g DW/(m2•day). It is shown that the maximum observed productivity of D. salina in the conditions of natural light in the southern regions of Russia cannot exceed 26 g DW/(m2•day).
ISSN 1995-4301
Select viewing options
