Effect of the cultivation medium composition on Dunaliella tertiolecta sensitivity to potassium dichromate
E.S. Stravinskene, Yu.S. Grigor’ev, T.L. Shashkova, M.A. Subbotin, M.A. Polosukhina
Section: Ecotoxicology
The effect of a model toxicant on the growth of the algae Dunaliella tertiolecta in Goldberg medium, prepared on the
basis of solutions of various sea salt complexes, as well as NaCl alone solution, has been studied. The growth of algae in
the controls was 10–15 times after 48 hours in all variants of media. Potassium dichromate at a concentration of 5 mg/L
had little or no effect on the growth of the test culture in media prepared from the sea salt solutions. Simultaneously, the
same concentration of potassium dichromate completely suppressed the algae growth in NaCl-media. The results of the
chemical analysis of all the studied sea salt solutions showed a ratio of the main ions close to that of natural sea water. All
studied samples of sea salt solutions contained 5 to 8% magnesium and calcium ions, which is a possible explanation for
the lower sensitivity of Dunaliella tertiolecta to potassium dichromate in these media, since the hardness of the medium
affects the bioavailability of toxicants for test organisms.
Article published in number 3 for 2021 DOI: 10.25750/1995-4301-2021-3-186-192
Views: 3
Evaluation of anthropogenic load on water bodies within the city limits
T.V. Noskova, M.S. Panina, O.M. Labuzova, T.S. Papina, E.G. Ilina
Section: Monitoring of natural and anthropogenically disturbed areas
The fluorimetric analysis of the content of formaldehyde, volatile phenols and oil has been performed in the samples of
atmospheric precipitation. Atmospheric precipitation (rain and snow) were collected in Barnaul from October 2013 until September 2018. The average concentration of oil in atmospheric precipitation was 0.07 ppm, volatile phenols – 0.006 ppm and
formaldehyde – 0.1 ppm. A seasonal increase of the oil concentration was revealed in the cold period of the year. For formaldehyde
a seasonal increase of the concentration has been revealed in the warm period of the year. Volatile phenols are characterized by
a constant emission into the atmosphere of the Barnaul regardless of the time of year. The anthropogenic load of the formaldehyde, volatile phenols and oil on surface waters within the boundaries of the city of Barnaul was calculated taking into account
average rivers’ discharge. Full-flowing the Ob River does not experience significant anthropogenic load within the boundaries
of the city of Barnaul, as regards of the studied pollutants. Its waters are able to dilute the concentration of incoming studied
organic pollutants from urban stormwater runoff to before MAC. For the Barnaulka River, the stormwater runoff within the
boundaries of the city of Barnaul is a serious source of pollution with oil and volatile phenols. Phenolic compounds pose especially high risk of pollution of the Barnaulka River. Contamination of the Barnaulka River with formaldehyde is not observed.
For the improvement current unfavorable environmental situation, it will be necessary to construct the urban treatment plants.
Article published in number 3 for 2021 DOI: 10.25750/1995-4301-2021-3-098-103
Views: 22
Infestation of pea seeds (Pisum sativum L.) with pathogenic microorganisms
T.P. Gradoboeva
Section: Agroecology
Injuriousness of seed infection is very high. So, the aim of our study was estimation of pathogenic microflora on
peas seeds and screening of cultivars on seed defeat with most harmful pathogenes. As a result of perennial monitoring of
contamination of peas seeds, it is revealed annual existing of fungi of genera Ascochyta, Fusarium, Alternaria, Aspergillus,
Pennicillum, Cladosporiumas well as agents of bacteriosis Pseudomonas syringae var. pisi on their surface. Fungi of genus
Ascochyta spp. were represented with two species: A. pisi, A. pinodes. Within fungi of genus Fusarium determined on peas
seeds, F. oxysporum var. pisi, F. avenaceum, F. sporotrichioides, F. culmorum prevail. Fungi composition and defeat of
cultivars with them varied in dependence of year conditions and cultivar. Significant part in complex of seed infection for
all year of study belongs to fungi of genus Alternaria. They were met practically on seeds of all cultivars (96.5–100.0%),
with except of cultivar L-1325 (Sweden). Most dangerous present agents of diseases often exist in mycobiota of seeds:
ascochyta blight (17.4–93.5%), fusariosis (6.5–68.8%) and bacteriosis (39.1–80.0%). 237 cultivars and genotypes of
peas of domestic and foreign breeding were studied. For study period (2014–2018) seeds were defeated in the highest
degree with ascochyta blight. Hard and very hard degree of defeat of seed with this disease was noted in 27.1 and 19.8%
of genotypes. For fusariosis defeat these parameters were 2.5 and 17.3%, for bacteriosis – 31.2 and 1.4%. Absence of
ascochyta blight on seeds noted in 12.2%, fusariosis – in 31.2%, bacteriosis – 13.5% of studied cultivars. As a result of
perennial evaluation perspective genotypes were selected (Tigra (Germany), Е-3907, Е-3335, Е-3767, Е-4030, Д-23417
(Russian Federation, Kemchug (Pamir)), which had defeat of seeds with ascochyta blight, fusariosis, and bacteriosis not
higher than 4% for all years of study. This parameter has high importance in practical breeding.
Results of the phenological observations of 21 species of the Clematis L. genus relating to 4 sections and 7 subsections, which are carried out in the South-Ural botanical garden institute of UFRC RAS (Ufa) from 2007 to 2020 are presented in article. Was noted the timing of the onset of 9 phenophases: breaking of buds, beginning and end of growth of shoot, beginning, termination and duration of blossoming, maturing of fruits, termination and duration of vegetation. Correlation analysis was used to assess the relationship between phenophases, the influence of species and annual meteorological features was estimated by two-factor dispersion analysis. It was revealed that the vegetation in clematis begins mainly in the III decade of April. The phases of the beginning and end of flowering are an individual feature for each species. Fruiting usually occurs 2-2,5 months after the beginning of flowering. Only 11 species out of 21 bear fruit, as the rest do not have time to form full-fledged seeds due to late flowering. Vegetation ends in late September-early October with the onset of the first frost. The onset of all phases, except for the duration of vegetation, is reliably influenced by species features. Phenodates of breaking of buds, growth beginning and end of shoot growth, the end of vegetation and the duration of vegetation is subject to fluctuations depending on the climatic conditions of a particular year.
Keywords: Clematis L., species, seasonal rhythm of development, phenodate
Application of artificial neural networks for identifying poorly formalized patterns in experimental become widespread nowadays. In the present work, we elaborated a prototype of a model for detection of water contamination with heavy metals. The model is a fully connected neural network (multilayer perceptron) designed by using the Python programming language and the TensorFlow software (Keras). It is intended for application in environmental monitoring of natural water bodies using chlorophyll fluorescence measurements which are considered as highly informative approach for probing photosynthetic activity in vivo and in situ. Fluorescence rise induced by application of a strong light pulse to the dark-adapted plant or algae (the OJIP transient) reflects a stepwise transition of the photosynthetic electron transport chain from the oxidized to the fully reduced state. To provide a quantitative analysis of the OJIP transient, a JIP test was introduced whose parameters describe energy fluxes through the photosynthetic electron transport chain. Our model uses OJIP transients and/or JIP-test parameters, measured in phytoplankton communities, as input data. As a result, it determines the probability of water pollution by heavy metals. In order to test the model, phytoplankton samples were taken from 9 water bodies of Pskov region and then treated with chromium and cadmium under laboratory conditions. For that, phytoplankton samples were exposed to cadmium and chromium salts (CdSO4 and K2Cr2O7) at two concentrations (20 and 50 μM) for three days, and OJIP curves were recorded and JIP-test parameters calculated at different stages of the experiment. In total, 419 curves were collected, and a whole dataset was analyzed. Results showed that accuracy of detecting the toxic effects of Cd2+ (after 2 or more hours of incubation) and Cr2O72– (after 9 or more hours of incubation) by the model achieved 90%. The highly accurate determination of the toxicity of heavy metals indicates a promising prospect for the application of machine learning technology in environmental monitoring.
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-134-141
Views: 46
Improvement of fluorometric method for polycyclic aromatic hydrocarbons determination in environmental objects
O.A. Plotnikova
Section: Methodology and research methods. Models and forecasts
The selection of suitable pre-sample preparation and analysis methods for effective monitoring of polycyclic aromatic hydrocarbons (PAHs) is essential. An important task is to control the PAHs content in various media. These substances, even at low concentrations, can pose a threat to public health, can have carcinogenic, mutagenic and teratogenic effects on living organisms. A distinctive feature of PAHs molecules is the ability to absorb energy and luminescence under the influence of UV radiation. In this regard, spectroscopic methods are promising for the PAHs determination.
The paper presents the characteristic absorption and fluorescence spectra of PAHs, and indicates their excitation and fluorescence wavelengths. An experimental study of the metrological characteristics of various spectroscopic methods has been carried out. The PAHs representative pyrene was determined by spectrophotometry and fluorimetry in solutions, as well as solid-phase fluorimetry with preliminary micellar and sorption concentration on a solid matrix. The use of aqueous micellar solutions of the nonionic surfactant Triton X–100 made it possible to enhance the analytical signals for the pyrene determination. The data obtained confirm the fact that the fluorescence method is characterized by a higher sensitivity than the method based on the registration of these substances’ absorption. The linear range of concentrations determined by the spectrophotometric method is more significant in comparison with the fluorometric methods and amounts to 14–10000 ng / ml. At the same time, the combination of preliminary micellar and sorption concentration with solid-phase fluorescence on a modified by surfactants viscose matrix made it possible to reduce the detection limit of pyrene to 0.8 ng / ml, which is especially important for the development of methods for controlling ecotoxicants contained in the environment in "trace" concentrations.
Section: Monitoring of natural and anthropogenically disturbed areas
An analysis is made of the natural-climatic characteristics of the formation of the ecological status of the atmospheric air in the city of Irkutsk. It is found that its chronic pollution is associated with a long-term annual exceedance of MAC for 5 to 6 specially hazardous pollutants, and with a persistent presence of suspended substances (up to 2.4 MAC) and benzo(a)pyrene (up to 7.8 MAC). The main volume of pollutants emissions corresponds to a long-lasting heating season (mid-September‒mid-May).
A zoning of the territory of the city was carried out according to the degree of the possible effect of topography and prevailing type of underlying surface (water, forest-park, and stone and wooden buildings) on air temperature in the atmospheric ground layer.
The zone of strong influence includes three types of microclimate of lowlands, with the January temperature deviations from 1.9 to ‒3.6°C from the Irkutsk, Observatory base weather station. Stagnant phenomena in this zone can promote formation of intense air pollution of residential and recreational territories. In this case, topography is the leading factor for the spatial differentiation of air temperature. Because of a high activity of the air exchange, the summit surfaces experience a weak impact of the environmental factors. The zone of moderate impact on slopes and planate territories reflects the local characteristics of the underlying surface. The dominant influence of stone buildings and roads on air temperature is most clearly pronounced in the center of the city on the right bank of the Angara; on the left bank, it is smoothed out by the influence of forested areas. With distance from the center of the city, similar air temperatures are typical for the slopes of different gentleness and aspect. This occurs as a result of significant differences in heat exchange in the dominant types of underlying surface.
Keywords: atmospheric air condition, microclimate of the city, deviations of air temperature in January, types of underlying surface, zoning of the urban environment
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-055-059
Views: 26
The stability assessment of the morphological and functional characteristics of rhizospheric strains of Bacillus subtilis using atomic force microscopy
Section: Methodology and research methods. Models and forecasts
The important advantage of atomic force microscopy (AFM) is the low power requirements for the studied objects, which allows studying living cells without fixation and with high resolution. It was proposed to use AFM to determine the morphometric and elastic-mechanical characteristics of the marker specie Bacillus subtilis isolated from the rhizosphere of the Cucurbita pepo L. crop in different vegetative phase of plant development. These characteristics of the microorganism are indicators of their functional activity and resistance to the action of biotic and abiotic environmental factors. It was shown that some parameters (length, width and height, elastic modulus, and the root mean square roughness) of B. subtilis isolated at different phases of plant growth were stable. So, elastic modulus of the bacilli was equal to 5.9 ± 0.2 MPa in plant sprouting phase, 5.8 ± 0.1 MPa in the phase of budding, 6.0 ± 0.3 MPa in the phase of flowering 5.7 ± 0.3 MPa in the phase of fruiting of the plant. The indicator of the root mean square surface roughness was equal to 37.5 ± 0.6 nm in plant sprouting phase; 35.1 ± 4.6 nm in the phase of budding; 31.8 ± 2.8 nm in the phase of flowering and 40.0 ± 2.1 nm in the phase of fruiting of the plant. AFM study of the surface of B. subtilis cells revealed a change of the adhesion force of the studied strains. This indicator was equal to 32.0 ± 6.0 nN and 41.0 ± 8.0 nN in plant sprouting and budding phases respectively. And the adhesion force was increasing significantly in the flowering and fruiting phase in comparison to the first phases (73.0 ± 5.0 nN and 69.0 ± 3.0 nN, respectively; p <0.05).
The use of atomic force microscopy technology has shown its effectiveness in studying of the stability of the morphometric and elastic-mechanical characteristics of B. subtilis, which are indicators of functional activity of the plant. It was suggested an approach to the development of a methodology for assessing and managing the quality of ecosystem components based on the use of a new information method for the study of marker biological objects.
Keywords: Bacillus subtilis, rhizospheric bacteria, bacterial-plant symbiosis, atomic force microscopy, morpho-functional properties of bacteria
Section: Methodology and research methods. Models and forecasts
A method for the comparative assessment of the productivity of marine water areas based on an analysis of the vertical distribution of the glow intensity (bioluminescence) of planktonic communities is presented. In the coastal waters of Crimea, 5 regions were marked out, which differ in the vertical distribution of the intensity of bioluminescence, the total biomass, and the number of plankton communities. It is noted that planktonic communities that have a quick response to changes in the ecosystem can serve as an operational indicator of the effects of various environmental factors on it. Bioluminescence intensity measurements do not require laboratory processing of samples and are carried out in real time.
A methodology for calculating the integral intensity of bioluminescence of hydrobionts (IIBH), which characterizes the total biomass, the number of aquatic organisms, and the biological productivity of water, is described. For selected areas, IIBH calculation was performed. A comparative assessment of the water productivity of the selected areas showed that the highest IIBH (an average of 37830 pW∙cm–2l–1) was observed on the southwestern shelf of Crimea. In the area of the Kerch Strait, IIBH was 1.24 times less than on the highly productive south-western shelf of Crimea. In the north-western deepwater part of the sea, stable stratification of the waters promoted the formation of two layers with a high concentration of hydrobionts located at depths of 8–14 m and 40–45 m. At the same time, IIBH of the upper layer was the smallest in the study area and was 8 times lower than the value on the south-western shelf of Crimea. The results obtained on the productivity of water areas and the total biomass of plankton communities serve as the basis for the development of measures for the rational use of natural resources.
Keywords: bioluminescence, phytoplankton community, vertical distribution, water productivity
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-031-037
Views: 9
Zoobenthos of the Severnaya Dvina River delta
M.A. Studenova, I.I. Studenov, D.V. Chupov, A.S. Samodov
Section: Monitoring of natural and anthropogenically disturbed areas
Systematic studies of zoobenthos at the delta of the Severnaya Dvina river begun in 2012. This study contains the most complete information about the taxonomic composition of zoobenthos of the area, the number and frequency of taxons, the number and biomass of each of the taxa. Twenty taxons belonging to 6 types and 11 classes of invertebrates were found in zoobenthos during the whole period of research (2012-2018). The average number of taxons per 1 station during the entire research period was 9, ranging from 5 in the Korabel’ny arm to 16 in the Murmansk arm. Oligochaetes, bivalvia, and chironomidae larvae were found in samples at all stations each year. Isopods, dayflies larvae and beetle larvae were found with lowest occurrence rate. Average value of Shannon ’s zoobenthos index at the delta of the Severnaya Dvina river was 1.21, varying from 0.70 (Maimaxa and Kuznechikha branches) to 1.84 (Murmansk arm). The number of invertebrates over the years varied very widely - from 640 spec/m2 (Korabel’ny arm, 2018) up to 16573 spec/m2 (Murmansk arm, 2014), averaging 5704 spec /m2. Oligochaetes and сhironomidae larvaes were the most numerous. The biomass of invertebrates at the delta of the Severnaya Dvina river varied very widely - from 0.29 g/m2 (Korabel’ny arm, 2017) to 25.3 g/m2 (Murmansk arm, 2014), averaging 6207 mg/m2 for all observation years. The base of biomass was formed by Oligochaetes, their participation in the formation of total biomass reached 94.6%. An average oligochet index was 57.8%. The water condition of the delta of the Severnaya Dvina river was classified as moderately contaminated, according to the values of the oligochet index.
Keywords: Severnaya Dvina river, zoobenthos, taxonomic composition, number, biomass
Article published in number 2 for 2021 DOI: 10.25750/1995-4301-2021-2-060-065