No 2 (2024)

The results of a complex hydrochemical and hydrobiological study of salt lakes in the South-Eastern Transbaikalia during the period of moisture change are presented. The studied lakes, according to the geochemical classification, belong to the chloride and soda types. The taxonomic diversity of aquatic biota decreases while the salinity increases and the hydrochemical type of lakes changes from soda oligo-mesohaline (4–16 g/L) to chloride eu-hyperhaline (33–70 g/L) and to soda hyperhaline (128–231 g/L). In soda oligo-mesohaline and chloride lakes the phytoplankton taxonomic composition is similar and is represented by green and diatom algae, as well as cyanobacteria. Submerged aquatic plants are represented by Stuckenia pectinata in soda oligo-mesohaline lakes. Ruppia maritime was found in the Dabasa-Nor chloride lake. In zooplankton and zoobenthos, rotifers and chironomids dominated respectively. Quantitative characteristics of phytoplankton in oligo-mesohaline lakes are lower than in hyperhaline soda and eu-hyperhaline chloride lakes. The phytomass of submerged aquatic plants, on the contrary, is higher in oligo-mesohaline lakes. In the hypersaline soda lake Borzinskoye, zoobenthos and zooplankton organisms are represented by planktonobenthos species, namely Anostrica, with low abundance.

Japanese cattail (Typha japonica Miq., section Ebracteolatae) has been restored to its valid taxonomic status and listed as one of the floras of the outmost southern Sakhalin and Kuril Islands for the first time. These are the first records of T. japonica in Russia. With the unique geography and current molecular data (rpl32-trnL intergenic spacer), the latter cattail’s combination of morphological characters clearly distinguishes it from all other species of sect. Ebracteolatae (including T. caspica, T. elata, and T. tzvelevii), and also from all currently known bract-less species of Typha, including the Eastern cattail (T. orientalis C.Presl.), with which T. japonica was arbitrarily synonymized previously.

The bottom communities of a nearshore zone of Valaam archipelago (Ladoga Lake) have been investigated. The stations were located in the littoral, sublittoral and profundal on the depth 1–25 m. The three regions with different characteristics of the coast shore and relief were researched. The sampler-syringe was used to collect benthos because it works the whole of grounds variety in the nearshore. The quantative characteristics of the bottom communities had been optimally described with the depth ranges. The wave activity has significantly affected only on the numbers of zoobenthos in the upper 10 m. The changes of numbers and biomass have been described more preciously by the openness of the bays in depth from 1 to 10 m. There were the biggest numbers and biomass of zoobenthos in littoral of the close bay. In the semi-close bay and on the open coast the maximum abundance of benthic invertebrates shifted in sublittoral (depth >8 m), where waves less affected on the benthic communities. The types of ground had affected significantly only on taxonomical composition. In general, preferential effect on the quantity characteristics of benthos on the rocky slope zone have features of shore (openness and depth patterns). These data can be used for the analyses of next influences on the nearshore benthic community and for the analyses and modelling the commercial resources and their forage base.

Dependence in water bodies between the degree of anthropogenic impact and the composition of lipids and fatty acids (FA) separately liver, foot and body of L. stagnalis has been examined. The lake located within the city limits is susceptible to various types of pollution, the lake in the national park zone is clean. The ecological condition of the different lakes probably influenced the composition and content of total lipids and fatty acids of L. stagnalis. The highest lipids have been noted in the liver of the snail. In the body, liver and leg of the species the lipids phosphatidylcholine and phosphatidylethanolamine dominate, the FA — polyunsaturated acids. The change of the lipid and FA content of the L. stagnalis in lakes is probably due to the high concentration of organic compounds, heavy metals.

The main chemical composition and content of mercury in the muscles of freshwater fish species Xenentodon cancila, Notopterus notopterus, Anabas testudineus, Channa striata, Ch. gachua, Clarias batrachus from the rivers of the Cai South Vietnam, and their body sizes, was studied. A trend of more intensive accumulation of mercury, protein and fat in the muscle tissue of females compared to males was revealed. A significant relationship between the content of mercury and body size, as well as the content of mercury and the proportion of protein in the muscles, was not established in most of the studied individuals. Trophic patterns of mercury accumulation in fish muscles were confirmed: its content increased from euryphages to zoophages (facultative predators). An exception is the euryphage Clarias batrachus, which surpassed many facultative predators in mercury content. It is shown that individuals of the same species living in the biotopes of the Kai River with different hydrodynamic and hydrochemical conditions differ in weight, length, content of protein, fat and mercury in muscle tissue.

The influence of different types of microplastics (MP) and ash after burning a mixture of macroplastics selected in the supralittoral of the Barents Sea on the development of traditional test objects of the culture of the green microalgae Scenedesmus quadricauda and the culture of cladocerans Daphnia magna in chronic experiments was studied. In terms of inhibition of algal growth at a concentration of 3 mg/L MP, the PU sample showed the highest toxicity, followed by HDPE (white), HDPE (red) and contact EPS in descending order of toxicity. PP was non-toxic. Ash in the concentration range of 0.01-1000 mg/L did not significantly inhibit the growth of Scenedesmus quadricauda. For Daphnia magna a more expressed decrease in the average linear size was noted with the addition of intact EPS, and the stimulation of fertility was significantly higher in the presence of contact EPS. When comparing the effect of intact and contact PU on D. magna, the death of all individuals under the influence of intact PU was found, while adding PU, survival remained at the control level. MP particles and ash affect the trophic activity of daphnia when fed with chlorella, but this effect does not lead to changes in fertility and growth during long-term observation.

Plastic pollution of Asian rivers is one of the global problems of the region. Work was carried out to identify microplastic particles in the tissues of some species of hydrobionts from the Mekong Delta, one of the largest rivers in Southeast Asia. The method of tissue decomposition with 30% hydrogen peroxide was used. The presence of microplastic particles was revealed in 11 out of 12 fish species and in 6 crustaceans species. The dominant type of plastic in both fish and crustaceans was blue-violet fibers.

The results of the quantitative assessment of the microplastics (MPs) content in the Siberian Wood Frog (Rana amurensis) larvae and gastrointestinal tract (GIT) of adults from the floodplain of the Goloustnaya River flowing into Baikal Lake are presented. MP particles were found in the GITs of 83% (n = 18) of Siberian Wood Frogs aged 1+ to 4+. In the GITs of R. amurensis adults, MP particles were represented by microfibers (84.6%), microspheres (6.2%), microfilms (6.2%), and irregularly shaped fragments (3.0%). The sizes of MPs range from 0.3 to 5 mm. The average number of particles in frog’ GITs was 3.5 ± 3.6 per individual, with a spread from 0 to 11.6 particles. No significant correlations were found between the level of MP accumulation and the age of individuals of different sexes. No MP were found in R. amurensis larvae (n = 120), which is largely due to the low productivity of temporary shallow breeding water bodies in the floodplain of the Goloustnaya River, which are experiencing powerful anthropogenic pressure (transport, grazing, hay harvesting). The detection of MP in the GITs of adult Siberian Wood Frogs indirectly indicates contamination of the valley and the mouth of the Goloustnaya River, including the coast of the Baikal Lake. The data obtained in this study are the first evidence of the presence of MP in amphibians in the Russian Federation.

Our previous studies showed that the change in the plankton response to light could be an indicator of environmental pollution. This study experimentally reveals that the response of Daphnia magna Straus and Daphnia pulex plankton ensembles to photostimulation depends on the intensity of the attracting light. This makes it difficult to identify the occurrence and change of pollutant concentration. The large variability in the magnitude of the behavioral response is caused by the nonlinear response of plankton ensembles to the intensity of the attractor stimulus. As the intensity of the photostimulation increases, the variability of the phototropic response passes through increase, decrease and relative stabilization phases. The paper proposes a modification of the photostimulation method — paired photostimulation involving successive exposure to two photostimuli of increasing intensity. The first stimulus stabilizes the behavioral response, while the increase in response to the second stimulus makes it possible to more accurately assess the responsiveness of the plankton ensemble. The study demonstrates good reliability and increased sensitivity of this method of detecting changes in environmental toxicity compared to single photostimulation or traditional bioindication through the survival rate of test organisms.

During the study of the macrophytobenthos annual cycle of the aquatic component in the Cape Martyan Reserve, it has been found that sporophytes of the invasive transforming species Bonnemaisonia hamifera Hariot (Trailliella phase), naturalized in coastal waters off the Southern Coast of Crimea (SCC), abundantly form specialized organs of asexual reproduction. Mature tetrasporangia were registered in autumn at every zone of the phytal. Their morphology and morphometry, which have an important diagnostic value, were identified and measured. It was found that any thalli cells (except apical ones) could turn into sporangia, with the maximum number being formed in the terminal branches, where rows of up to 3–4 pcs are most common. Considering the fact that the formation of tetrasporangia occurs only in a narrow range of light-temperature conditions of a short day typical for autumn and spring, we showed that in the SCC the favorable period for this process lasts from the first decade of October to the second decade of December. In spring, in deep open water areas near the SCC, under modern climatic conditions, the formation of tetrasporangia is limited by water temperature, and therefore is unlikely. However, in relatively isolated shallow bays and lagoons, characteristic of other coastal regions of the Azov-Black Sea basin, it is possible due to local water temperature rise in the first half of March. Still, the ability of sporophyte thalli for vegetative reproduction by forming an unlimited number of fragments, that retain their viability and the potential for further fragmentation, remains likely the key factor ensuring the scale and rapid spread of B. hamifera in the SCC and in the Azov-Black Sea region as a whole.

The results of a study of the accumulation of microplastics in the caught alluvium of the river. Volga near the city of Tver. There were significant soil samples within the city, upstream and downstream of the river. Sample processing was carried out according to the modified method of the US Atmospheric and Oceanic Administration (NOAA). Microplastic particles are found in all samples, limiting the number of coverages in the inclusion area for the production and increase in the amount of plastic. It was found that films, granules and fragments of plastic particles ranging in size from 1 to 2.5 mm along the largest axis predominate in all selected samples.