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  • Development of the formulation and technology of a new fish culinary product "Cream cheese fish from blue catfish" enriched with iodine of kelp of the White Sea

    Novozhilova, E.A.; Shokina, Y. V.; Reshetnik, E.I.; Zakharova, L.M.; Pakusina, A.P.; Pashina, L.L.; Shkolnikov, P.N.; Tikhonova, P.А. (2024)
    Vestnik of MSTU
    Expanding the range of products based on the rational use of available fish resources is a current direction for the development of the food industry of the Russian Federation. Blue catfish, a little-used fishery item in the Northern Basin, was chosen as a raw material for the development of a fish culinary paste product. Blue catfish meat is significantly watered (up to 93 % of the total mass), as a result there are currently no technologies for deep processing of fish for food purposes. During the research, the technology of a new fish culinary product "Fish cream cheese from blue catfish, enriched with iodine from White Sea kelp" has been proposed in an assortment, and recipes have been developed, optimized in the MatLab program. The amino acid composition of blue catfish meat as well as indicators of the nutritional value of new products have been considered. The energy value of 100 g of product varies from 120 to 150 kcal, the mass fraction of protein is 8.5–11 %; fat – 9–13 %; carbohydrates – 2–2.5 %. The iodine content in a unit of consumer packaging of the product "Cream cheese fish from blue catfish with pickled seaweed" was experimentally established to be 340 mcg per 100 g; a 44 g serving of this product contains 100 % of the recommended daily intake of the micronutrient (150 mcg). The developed product "Cream cheese fish from blue catfish with pickled seaweed" can be classified as "enriched with iodine" when the amount of its daily consumption (25 g) is indicated on the consumer packaging.
  • Assessing the effectiveness of local organic materials as sorbents for oil spill response in Arctic waters

    Vasileva, Zh.V.; Trishina, A.S. (2024)
    Vestnik of MSTU
    The paper presents the results of a comparative assessment of the sorption characteristics of regional natural raw materials of organic origin: sphagnum moss (Sphаgnum palustre L.), fucus algae (Fucus vesiclousus), a composite based on them and peat in comparison with the synthetic sorbent OilSorb used in the practice of emergency rescue units to eliminate accidental oil spills. Experimental data have been obtained on potential pollutants in the Barents Sea (oil ARCO and diesel fuel) and the water capacity of sorbents for standard conditions at temperatures of 21–23 °C according to GOST 33627-2015 and in the temperature range of 10–12 °C typical for the summer period on the Kola Peninsula. The sorption characteristics of the materials under study have been evaluated in the "sea water – petroleum product" system, which simulates a real oil spill in the marine area. Tests in a model system simulating real conditions demonstrate significant changes in the efficiency of using sorption materials shown by them under standard conditions. The study has established the dynamics of the distribution of sorbed oil products and water in the materials under consideration, as well as residual oil products in the water of the "sea water – ARCO oil" and "sea water – diesel fuel" systems at different exposure times. During an exposure time of 30, 60, 90 minutes under the conditions of a system simulating a real oil spill in the water area, the material based on sphagnum moss has the most effective and time-stable indicators of sorption of oil products.
  • Macrozoobenthos in the estuary of the small salmon river of Sakhalin Island on example of the Gornaya River

    Korneev, E. S.; Labay, V. S.; Zhivoglyadova, L.A.; Berezova, O.N.; Sharlay, O.B.; Abramova, E.V.; Akhmadeeva, E.S. (2024)
    Vestnik of MSTU
    Estuaries as a connecting link between freshwater and marine ecosystems play a special role in salmon rivers. The success of adaptation of juvenile salmonids during the transition to the marine period of life depends on the conditions in estuaries. The work continues the previously started series of publications on the rivers of Sakhalin Island. Using the example of one of the small watercourses in the southeastern part of the island, the hydrological parameters and the structural organization of benthos communities in the atypical estuary have been considered. In the absence of storm surges, penetration of sea water into the water body does not occur; at high tide, water with a salinity of more than 12 psu is observed only at the mouth at the bottom; at low tide, the estuary is completely filled with water with a salinity of 0.1 psu and lower. Studies of the hydrological regime and composition of the bottom fauna were carried out in July 2022. Zoobenthos samples were taken along the longitudinal profile of the estuary at five sections (75 samples in total). Most of the estuarine reach is inhabited by species characteristic of the lower parts of the island watercourses. High environmental variability determines the formation in the estuary of young and unstable benthos communities represented by rapidly reproducing small-sized species.
  • Application of the "electronic nose" for evaluating volatile compounds of semi-finished small fish

    Alloyarova, Yuliya V. (2023)
    Vestnik of MSTU
    The production of canned food is one of the dynamically developing segments of the fishing industry. An instrumental assessment of the composition of highly volatile fractions (aromas) of smoked semi-finished capelin products sent for the production of canned food has been carried out using a MAG 8 odor analyzer in the equilibrium gas phase above the samples. To reliably establish differences in the composition of highly volatile compounds, the method of preliminary concentration of components in a sampler has been used. After saturation of the free space above the sample, the signals increased from 2.5 to 3 times when the sensors were loaded with the equilibrium gas phase. However, no fundamental differences in the nature of the influence of different methods of processing semi-finished capelin products have been established. Under native (natural) conditions for the formation of the odor of capelin samples and their preliminary concentration in the equilibrium gas phase, the qualitative and quantitative compositions of the odor differ, but the tendency remains for a higher content of compounds in the sample treated with smoke gel compared to frozen capelin and the sample treated with a smoke-air mixture. For saturated vapors, it has been established that according to 3 parameters (contributions to the sorption of sensors 1, 3, 8), samples treated with a smoke-air mixture and smoke gel have a similar composition (unlike frozen capelin). Sensors 5, 6 and 7 do not distinguish the smell of all samples, i.e. they react to volatile compounds of capelin. Sensor 4 reflects the proximity of the moisture indicators of frozen capelin and capelin treated with smoking gel. As a result of the correlation analysis, the correspondence of the obtained chemical samples has been established, including a greater influence on the composition of highly volatile fractions (aroma) when using a smoke-air mixture compared to using a smoking gel.
  • Neural networks as a tool for improving the mathematical model of ship motion

    Pashentsev, S. V. (2023)
    Vestnik of MSTU
    Using neural networks opens up great opportunities for studying mathematical models of ship motion. Correction by a network of identified parameters of the selected model should be as adequate as possible to the results of standard full-scale tests defined by the IMO Resolution N 137 of 2002. A mathematical model in displacements is considered, containing 16 parameters that determine the hydrodynamic forces acting on the ship's hull and steering gear, and is the source of a data set for training the network by randomly varying the parameters and subsequent computer testing. The standard maneuver is a steady-state circulation with fixation of the maneuvering elements: diameter, linear velocity, drift angle and angular velocity of rotation. Improving the quality of the model has consisted of changing its parameters and minimizing the mean square errors of the values of the maneuvering elements obtained during testing. For these purposes, a neural network with 16 inputs (model parameters) and four outputs (maneuvering elements for steady-state circulation) has been built. The data set for training the network was obtained using a program developed by the authors and intended for calculating parameters and conducting maneuver tests. A tanker with a displacement of 30,000 tons was chosen as a test object. Various options for network architecture and tools for working with it have been considered; the Statistica Neural Nets (SNN) software environment and the ANN package in the SciLab environment have been used. Comparative assessments of the results of working with these tools have been given.
  • Results of a statistical study of types of single-phase faults in low-voltage ship electrical networks

    Kazhekin, Ilya E.; Kharitonov, Maxim S. (2023)
    Vestnik of MSTU
    The increase in the power supply of ships is manifested in growth of ship power plants' capacity, the total length of cable lines, and the number of electrified mechanisms. With the development of marine technology, the severity of the consequences of damage to ship electrical equipment and the costs of its maintenance and repair increase. The search for ways to improve the reliability and safety of electrical equipment should be based on design and technological solutions at the stages of its development and production, as well as an analysis of various factors that may appear during the operation of marine equipment and affect the condition of ship electrical systems. During studying these factors, it has been revealed that one of the common types of damage to electrical equipment of marine equipment is single-phase short circuits, the causes of which are varied. Preventing short circuits is labour intensive and in some cases impracticable. However, understanding the characteristics of this type of damage to low-voltage equipment is necessary to improve the reliability and safety of ship electrical systems. The conducted research is based on a survey of ship electrical mechanics. The results of the surveys have made it possible to analyze the frequency of occurrence of single-phase insulation faults, the duration of their existence, to identify the most likely places of occurrence of short circuits and equipment that is more susceptible to such damage compared to other elements of the electrical power system.
  • Solving the problem of optimizing fishing activities.

    Lisienko, S. V.; Ivanko, N. S. (2023)
    Vestnik of MSTU
    A model for optimal planning of fishing activities has been proposed. It includes the formation of a biological component (a set of fishing objects considered taking into account their distribution over fishing zones) and a technological component (a set of fishing vessels and fishing technologies). On the basis of these two components, the technological chain "field object – production vessel – production technology" is formed. For each type of fishing vessel, it is permissible to use a certain type (or several types) of fishing technologies that are directly related to fishing objects, their catch can be carried out only using a certain production technology. Particular attention in the model is given to the problem of determining the optimal quantitative composition of the production fleet. The optimization criterion is the minimization of the costs associated with the fishing activities of specialized vessels, provided that the specified volumes of catch are achieved. The costs are directly related to the types of vessels used, fuel costs depending on the vessel's home port and the time required for loading and unloading operations. In the optimization problem, estimates of the weighted average daily catch and fishing time are used to account for most of the costs associated with the extraction of aquatic biological resources. The optimization algorithm is considered on the example of the Commander squid (Berryteuthis magister) in the North Kuril zone. In the area under consideration, squid production is carried out using trawl technology. The main types of vessels engaged in squid harvesting are large-capacity and medium-capacity vessels.
  • Fish quality monitoring for sustainable product safety.

    Reznichenko, I. Yu.; Egushova, E. A.; Donchenko, T. А. (2023)
    Vestnik of MSTU
    To provide consumers with high-quality and safe products, to prevent the entry of low-quality and dangerous food products into the consumer market, monitoring programs are provided. The results of monitoring samples of frozen fish of various families and species for the period 2020–2022 have been given. Labeling, organoleptic indicators of fish samples have been analyzed for compliance with the requirements of regulatory documents. The mass fraction of glaze, the mass fraction of phosphates in terms of P2O5, the content of histamine, toxic elements: lead, cadmium, mercury, arsenic have been determined. Labeling deficiencies are revealed in 1.3 % of the samples. A small, inaccessible font (less than 9 points) makes it difficult for the consumer to obtain complete information about the product. An excess of the mass fraction of glaze on average 0.7–0.8 % in pike perch samples has been revealed. The actual values of the mass fraction of phosphates have not exceeded the maximum allowable limits. The lowest content of phosphates has been noted in samples of pike perch (from 2.3 to 2.0 g/kg), the highest in pink salmon (from 5.0 to 4.1 g/kg) and salmon (5.2–4.7 g/kg). The content of histamine in all samples has been within the normal range. The smallest amount of histamine has been found in samples of mackerel (from 18.0 to 11.0 mg/kg) and pollock (17.0–11.0 mg/kg), the largest in pink salmon (25.0–16.0 mg/kg) and herring (22.0–19.0 mg/kg). The concentration of heavy metals has not exceeded the maximum allowable values. The results obtained are of practical importance for manufacturers in the development of labeling that satisfies consumer demand for information about the product and for consumers in the formation of the diet.
  • Development of methodology for creating technologies for processing low-grade semi-finished products of fish oils and fatty waste.

    Petrov, B. F. (2023)
    Vestnik of MSTU
    The development of fish oil production in Russia requires solving a number of environmental issues. It is necessary to develop technologies for processing low-grade semi-finished products of fish oils and fat waste. Currently, this problem remains unresolved. In the course of the study, the physicochemical properties of fat-containing objects (semi-finished product of technical fish oil with acid number of more than 20 units; soap stock after fish oil refining; fatty foam mass after flotation treatment of industrial wastewater from fish oil production) have been determined and rational directions for their use have been established. It is noted that these objects contain lipids with a high degree of hydrolysis and unsaturation. The developed methodology for creating private technologies for processing technical fish oils and fatty wastes into target products for technical purposes makes it possible to obtain an oil-in-water dispersed system and a fatty acid concentrate from the objects of study. The resulting products can be used as a basis for the production of anti-adhesive, surface-active, film-forming and anti-friction technical reagents for various industries (including food industry).
  • Investigation of the biopotential of products of hydrolysis of waste from cutting the white-legged shrimp Penaeus vannamei.

    Mezenova, O. Ya.; Agafonova, S. V.; Romanenko, N. Yu.; Kalinina, N. R.; Volkov, V. V.; Merzel, J.-T. (2023)
    Vestnik of MSTU
    The relevance of studying the biopotential of shrimp waste and their hydrolysates is due to the need for complex processing of secondary raw materials of aquatic organisms to obtain useful products. At the fish processing plant Vichyunai-Rus LLC when manufacturing food products from white-legged shrimp, up to 60 % of the mass of waste (cephalothorax, shell) remains. This raw material contains valuable organic components, but is not processed. The paper proposes its complex processing with the production of hydrolysates in two ways – high-temperature and enzymatic. During thermohydrolysis in the aquatic environment, three fractions are formed from shrimp waste (fatty, water-soluble and water-insoluble). After separation, the water-soluble fraction was sublimated, and the water-insoluble fraction was dried by convection. The fat fraction was further purified by washing in warm water. The general chemical composition of shrimp waste and hydrolysis products has been studied. It has been shown that water-soluble hydrolysates are a good source of protein components (66.6–71.6 %). In comparative studies of the amino acid composition of water-soluble hydrolysates, the presence of all essential amino acids is established with minor differences between the samples. Both hydrolysates are dominated by alanine, arginine, glycine, isoleucine, lysine, aspartic acid, tyrosine, valine (3.3–6.4 g/100 g of protein). In terms of formol-titratable nitrogen in fermentolisates, alkalase ferments shrimp waste more actively than collagenase. The fatty acid composition of lipids isolated by thermohydrolysis from shrimp waste has been analyzed. Shrimp oil is characterized by a high content of polyunsaturated fatty acids (44.7 %) with a relatively low content of omega-3 family acids (10.7 %) and a high content of omega-6 (33.9 %) at a ratio of 1 : 3.2 (close to the physiologically recommended). The organoleptic characteristics of water-soluble and water-insoluble shrimp hydrolysates have been studied. Due to the content of valuable biologically active components in hydrolyzates, their use as food and feed additives – sources of active peptides, high-molecular proteins, minerals and chitinous components – is recommended.
  • The use of fermented minced fish with probiotics in the recipe composition of dry-cured sausages.

    Glukharev, A. Yu.; Barabashina, S. I.; Volchenko, V. I.; Zhivlyantseva, Ju. V.; Poteshkina, V. A. (2023)
    Vestnik of MSTU
    The paper analyzes the effect of using fermented minced fish (FMF) with the L. plantarum probiotic in the formulation of dry-cured sausages on the quality characteristics of the finished product in comparison with sausages based on unprocessed minced fish. The microbiological, physico-chemical, structural-mechanical and organoleptic properties of the product have been evaluated. The results have shown that dry-cured sausage samples with FMF had a higher content of probiotics (2,5×108 CFU/g) compared to the control sample (6,3×106 CFU/g), which allows a person to fully meet the daily requirement in probiotics with just through the use of 40 g of such a product. The use of FMF in the dry-cured fish sausages provides a safe pH value (5.21) and significant increase in total acidity (1.39 %) compared to the control sample (pH – 6.80 and total acidity – 0.45 %). It has been established that using FMF in the technology of dry-cured fish sausages can reduce the time of their manufacture by increasing the average rate of dehydration of the product. It has been determined that samples of dry-cured sausages with FMF have higher values of hardness and cutting force. A comprehensive assessment of the quality of sausages with FMF has shown good results – 76.85 % of the maximum possible level. Thus, the possibility of using FMF with L. plantarum in the manufacture of dry-cured sausages has been determined. The proposed method makes it possible to obtain a product with a high protein content (32.31 %), enriched with L. plantarum probiotics, having a low pH value and a peculiar sour-milk taste and aroma. Based on the results of the study, normative and technical documentation for this type of product has been developed and approved.
  • New species of freshwater bryozoans Plumatella sibirica (Phylactolaemata), Western Siberia (Russia)

    Gontar, Valentina; Sharapova, Tatyana (2023)
    Vestnik of MSTU
    Western Siberia is the least studied region with respect to the distribution, ecology, and systematic composition of freshwater bryozoans. The collection of material on freshwater bryozoans of the West Siberian Plain was carried out as part of study of the zooperiphyton of the water bodies of the Tyumen region (including the Khanty-Mansiysk and Yamalo-Nenets Autonomous Districts) in 1987–2016. As a result of the collected material analysis, description of a new species of phylactolemic bryozoans (Bryozoa) Plumatella sibirica has been presented. The new species has autozooids in the form of tubules with a rounded cross section. Phlotoblasts are oval, with slightly narrowed poles. Size and surface morphology of flotoblasts and sessoblasts distinguish the species from related species Plumatella repens (Linn?) and P. buschnelli (Wood). The maximum biomass of zooperiphyton in forest-tundra lakes has been noted in communities dominated by large colonies of Plumatella sibirica, where this bryozoan is the absolute dominant. In the course of further studies, a new species of bryozoans Plumatella sibirica may also be found in other regions of Siberia.
  • Application of tonal audiometry methods to assess the hearing of grey seals in air and water environments

    Pakhomov, M. V.; Zaytsev, A. A.; Litvinov, Yu. V.; Troshichev, Alexandr (2023)
    Vestnik of MSTU
    Anthropogenic noise load on the traditional habitats of marine mammals continues to increase due to the active development of the Arctic zone. The study of the hearing of Arctic seals is of great importance for the development of measures to reduce the impact of technogenic noise. During the study, a group of ten grey seals of different ages and genders has been trained to press a special key when demonstrating a pure tone sound with a frequency from the standard and extended set of frequencies recommended for pure tone audiometry. The experiments have been carried out by placing the key and the sound source in air and water (at a depth of 2 m) environment. The main indicator is the reaction time of the seal to the demonstrated stimulus. For each seal, individual audiograms for hearing in air and in water have been compiled using 32 frequencies. An analysis of the data obtained has shown that the reaction time can serve as an individual indicator in the study of the hearing of grey seals reflecting their age characteristics. According to the response time to sounds with different tone frequencies it is possible to establish biologically significant and indifferent frequencies for grey seals.
  • Features of the population structure of Fucus vesiculosus L. (Phaeophyceae) in different areas of the Murmansk coast of the Barents Sea, 2021

    Malavenda, S. V.; Nikulina, Victoria (2023)
    Vestnik of MSTU
    The age, size-mass and reproductive structure of the Fucus vesiculosus population in the areas of the Murmansk coast has been studied on boulder soils of the middle horizon of the littoral with weakened surf. In the studied areas characterized by different temperature conditions and the degree of anthropogenic impact the biomass of F. vesiculosus does not differ statistically significantly. The minimum population size has been found in the middle knee of the Kola Bay, the maximum – at the eastern stations. In the warmer Pechenga and Retinskaya Bays, receptacles form on thalli with more branching than in the Zelenetskaya and Yarnyshnaya Bays; thalli in western Murman have a lower age of appearance of receptacles. The linear dimensions of thalli and their mass do not differ in the studied areas. The beginning of zygote germination judging by the size of seedlings is the same on the entire coast. Maximum fertility is observed at the age of 2.5–3 years. Differences between the coenopopulations of F. vesiculosus in Western and Eastern Murman indicate the important role of climate in shaping the appearance of littoral vegetation. The current level of pollution in the Kola Bay has a negative impact on the survival of fucus seedlings, however, it can be concluded that the life span of thalli is high and the population is stable.
  • The interaction of endogenous and exogenous factors in the biological rhythms of the Arabesque greenling Pleurogrammus azonus in the Primorie waters

    Vdovin, Alexander; Chetyrbotsky, Alexander; Izmyatinsky, Denis (2023)
    Vestnik of MSTU
    Arabesque greenling Pleurogrammus azonus is an important commercial species in the waters of Russia and Japan. In the Russian waters of the Japan Sea, regular study of its biology was conducted in the waters of the Primorsky Krai, where annual trawl surveys were performed. Material collections covered the entire calendar year. Endogenous rhythms (internal biological clocks) play a crucial role in the coordination of biorhythms of the Arabesque greenling Pleurogrammus azonus. This assumption is confirmed by the different duration of exogenous and endogenous rhythms: the dynamics of the temperature index has a pronounced periodization equal to one astronomical year, and the duration of the mixed rhythms in the dynamics of physiological processes and main components changes with age. The relationship of somatic and generative growth with temperature oscillation is subjected to age-related variability. In juveniles, this relationship is not clearly traceable. At the beginning of puberty period, significant connections are manifested. Then the dependence of growth indicators on the temperature oscillation is reduced, as the selective ability of the Arabesque greenling to choose the temperature range increases. Selective ability to environmental conditions is largely determined not by individual but by group behavior.
  • Populations of long-clawed crayfish Pontastacus leptodactylus: Effect of commercial fishing on the size and age structure

    Alekhnovich, Anatoly (2023)
    Vestnik of MSTU
    Fishing affects the population of crayfish, while it changes the size and age characteristics. The size and age parameters of two populations of the narrow-clawed crayfish Pontastacus leptodactylus in the Loktyshi (Brest Region) and Krasnoslobodskoe (Minsk Region) reservoirs in Belarus have been compared. The Krasnoslobodskoye reservoir is intensively exploited with an annual catch of 3–4 tons of crayfish. There is no commercial fishing in the Loktyshi reservoir. Studies show that the average size of individuals in an intensively exploited population is smaller in comparison with a population where there is no commercial fishing for crayfish. Since crayfish fishing is regulated by a commercial measure (10.5 cm of total length) in intensively exploited populations, the average sizes of individuals are close to these limiting values. The life expectancy of crayfish is somewhat higher in the Loktyshi reservoir, where only amateur crayfish fishing is noted. Intensive fishing increases the mortality of females, whose annual survival rate is 37 %, while in the absence of fishing, the survival of females increases up to 57 %. The annual survival rate of males is 41–49 %. The fishing pressure leads to decrease in the survival rate of individuals and disappearance of crayfish aged 9–10 years from the population.
  • Changes of inorganic nitrogen compounds concentration in a mining enterprise wastewater by the microalgae Chlorella vulgaris

    Shcheglov, Gleb (2023)
    Vestnik of MSTU
    Wastewater contamination by nitrogen compounds is a serious problem for the mining, industrial and utility companies. Nitrogen can enter quarry effluent when explosives containing ammonium nitrate are used in blasting operations. This nitrogen pollution of water leads to environmental damage and human disease, companies that exceed the legal limits for nitrogen pollution are subject to fines. Nitrogen is removed from wastewater by biological methods, but their efficiency is low in the Northern regions of Russia due to climatic factors that hinder the vital activity of organisms. Therefore, it is essential to develop wastewater treatment technologies for the removal of nitrogen compounds. This study focuses on the ability of the microalgae Chlorella vulgaris to absorb and utilize various inorganic nitrogen compounds in mining effluents using the example of effluents from the "Karelsky Okatysh" mine and tailings dam (Kostomuksha, Republic of Karelia). Concentrations of ammonium, nitrate and nitrite in water and microalgal biomass in water samples have been investigated. A novelty of the study is the evaluation of pollutant concentrations in parallel experiments with different cultivation conditions. It has been found that when Chlorella vulgaris is cultivated at 26 °C, aeration and artificial light, the concentration of ammonium decreases. These results show the promising application of bioreactor technologies for the treatment of ammonium polluted wastewater.
  • Reconstruction of the conditions for the formation of red-colored sandstones of the Tersky coast based on a comparative analysis of the structure of ancient and modern deposits (Kola Peninsula)

    Neradovsky, Yu. N. (2023)
    Vestnik of MSTU
    The paper presents the results of studying the Riphean red-colored sandstones of the Tersky coast of the White Sea. 21 structural elements characterizing the conditions of rock formation have been considered, including 15 ancient and 6 modern deposits. Observations were carried out for 10 years in two areas of the White Sea coast. The purpose of the research is to establish the reasons for the absence of organic matter, the origin of the hematite admixture in the Riphean sandstones, and to assess the climatic conditions during their formation. These issues are key to identifying the Proterozoic red formation. The data have shown that some rock structures are similar in ancient and modern deposits. Such structures include, for example, wave ripples repeating in detail the dimension, shape, and orientation in both epochs, and therefore can be used to assess ancient marine sedimentation conditions. However, most of the structures testify to fundamental differences in the conditions of rock formation. It has been established that takyrs were systematically formed in ancient rocks and hematite was deposited, which indicates the arid climate in the Riphean and the specific composition of sea water. The most important difference between ancient deposits is the absence of fauna and flora in them.
  • Experimental evaluation of toxic resistance of benthic microalgae Thalassiosira excentrica Cleve 1903 (Bacillariophyta) under the copper ions impact

    Petrov, Alexei; Nevrova, Elena (2023)
    Vestnik of MSTU
    With an increase in anthropogenic pressure on the ecosystem of the coastal zones of the sea, the relevance of assessing the state of plankton and benthos communities also increases. In the course of the study, the dynamics of the number of cells of the clone culture Thalassiosira excentrica Cleve 1903 (Bacillariophyta) has been determined under the influence of CuSO4·5H2O of various concentrations (32–1024 µg·L–1) under the conditions of 10-day experiments. In the control and at a low concentration of Cu2+, the proportion of living cells remains almost unchanged. The threshold concentration of copper ions for the survival of T. excentrica is 128 µg·L–1. At higher concentrations of Cu2+ (256–1024 µg·L–1), a sharp inhibition and death of the culture has been noted already within 1–3 days. The increase in the absolute number of cells at low concentrations of copper (32–64 µg·L–1) is described by the sigmoid response curve of the test-object. The growth values increase by 4–8 times on the 1st–5th day and decrease by 25–30 % by the 10th day. At Cu2+ concentrations of 128–256 µg·L–1, there is no positive increase in the number of cells on days 1–5; on subsequent days, it decreases by 2 times or drops to zero. The intensity of the specific cell growth significantly decreases depending on the increase in the concentration of the toxicant. It has been found that on days 1–5, the specific increase is positive in the range of copper concentrations of 32–128 µg·L–1 and negative – at concentrations of 256 µg·L–1 and higher. In the period of 5–10 days, for all concentrations of the toxicant, the values of the specific increase are negative. The obtained results make it possible to recommend T. excentrica as a promising test object for toxicological experiments.
  • Taxocene of polychaeta of the Laspi Bay water area (the Crimea, Black Sea)

    Kopiy, Vera (2023)
    Vestnik of MSTU
    The coastal zone of Laspi Bay (the Crimea, Black Sea) is attractive for the development of recreational activities. It can negatively affect the state of the bay ecosystem and adjacent waters. The aim of this study is to assess the current state of polychaetes inhabiting the loose soils of the littoral and sublittoral areas of Laspi Bay. In 2016–2019 the fauna of polychaetes was studied in the waters of Laspi Bay. Macrozoobenthos were collected on cruises 84, 86, 96, 108 aboard the research vessel Professor Vodyanitsky and in coastal expeditions. 89 samples were taken (19 deep-water, 70 coastal). 45 species of polychaetes were identified. The average abundance of Polychaeta was 2 368 ± 467 ind./m2. The average biomass was 44,128 ± 13,919 g/m2. Terebellides stroemii makes a significant contribution to the formation of these indicators. The ranked series by density index is headed by T. stroemii, Nephtys hombergii and Melinna palmata. The largest abundance of species is noted at a depth of 46 m where the soil is represented by sand and pebbles. The highest number is noted at depths of 93.5–98 m. Prionospio сirrifera makes the main contribution to the total number. The highest biomass is noted at depths of 53.5–58 m. T. stroemii makes the main contribution to the total biomass. In the Laspi Bay waters are recorded characteristic species – P. сirrifera and Micronephthys longicornis. They are found both in shallow waters and at great depths. Rare species found only at one station include 18 polychaete species. The results obtained give an idea of the taxonomic composition of polychaete worms in the waters of Laspi Bay and can be useful for further monitoring of this area.

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