Vol 11, No 2 (2018)

External morphological and genetic structures of 94 individuals of Canthocamptus staphylinus Jurine (Harpacticoida, Copepoda, Crustacea) from ten European water bodies differing in type, including species type locality, have been analyzed. Significant distinctions of populations on six morphological features and morphometric indexes are established. The variability of both morphological and genetic markers is noted. As a result, two main species morph forms are allocated, typical and small. According to nucleotide, the variety of mitochondrial DNA harpacticoid specimens falls into ten haplotypes and three clades on the phylogenetic tree. One of them corresponds with the group isolated on morphological features (harpacticoids from the Sysola River basin, Komi Republic). The same-sex population from Lake Pääjärvi (Finland), which is morphologically indistinguishable from the population from a type locality, is considerably divergent by nucleotide sequences of mtDNA. The role of geographical isolation and ecological factors in C. staphylinus microevolution is shown.

Morphological and physiological properties, the partial sequence of the 16S rRNA gene, and the ultrastructure of a novel halotolerant hydrocarbon oxidizing bacterium Kocuria sp. (strain ICIS A2.2) isolated from the association with the ciliate Cyclidium sp. have been characterized. Morphological and ultrastructural changes have been revealed in cells of the studied strain while growing in a media with different carbon sources (sucrose or diesel fuel). At the cellular level, the enlargement of the cells, changes in their shape, and the formation of aggregates occur. At the subcellular level, both the number and size of cytoplasmic membrane bodies increase and electron-transparent inclusions appear. These changes may be considered a result of adaptation to a medium containing hydrocarbons.

In 2014, for the first time in the last 55 years, phytoplankton of the water bodies of the Vychegda River Basin has been studied. The basis of plankton communities is made up of algae from Bacillariophyta, Chlorophyta, and Cyanoprokaryota divisions. In terms of quantitative indicators, leading groups with the prevalence of diatoms are identified. The range of abundance and biomass of algae is 3.92–27.82 million cells/L and 0.3–2.9 mg/L, respectively. The biomass of phytoplankton and hydrochemical indices make it possible to classify the studied water objects as second–fourth water-quality classes, with an increase in trophic status under conditions of an anthropogenic load increase.

Findings of the cladoceran Diaphanosoma mongolianum have been recorded in lakes Pleshcheevo (since 2004) and Nero (since 2007) in Yaroslavl oblast at the northern boundary of its range. Similar species D. brachyurum, previously described in both lakes, is found in insignificant numbers. In 2004–2015, the seasonal abundance, spatial distribution, and diel vertical migration of D. mongolianum were studied in deep mesotrophic Lake Pleshcheevo. The species was found in the plankton from early June until October, with the maximum abundance in July–August. The late appearance of males and gamogenetic females (September) is characteristic of its population. D. mongolianum was the most abundant in the epilimnion of the pelagic zone, where it performed diel vertical migrations, concentrating in the surface layer (0–2 m) at night and at a depth of 2–6 m during the day.

Data on the initial stage of macrozoobenthos formation in the Taishir and Durgun reservoirs in western Mongolia in 2010–2015 have been generalized. A taxonomic list of macrozoobenthos is presented; 15 species have been recorded in Mongolia for the first time. In the Durgun Reservoir, the formation of bottom sediments and communities of invertebrates in the near-dam part is accelerated due to the water-flow transport of reed beds and invertebrates from Lake Khar-Us. The macrozoobenthos in the Taishir Reservoir is formed first due to consumers of terrigenous organic matter (decaying terrestrial vegetation and soils), and then by inhabitants of sapropelic mud; complexes of filter feeders, Spongilla lacustris (L.), are formed in the profundal zone. The process of macrozoobenthos development in the reservoir is similar to that in lowland reservoirs. After the construction of the reservoir, quantitative characteristics of macrozoobenthos increased downstream of the dam in the Dzabhan River and rheophilic species were replaced by limnophilic ones.

The data of long-term ecological studies (1999–2014) are used for assessing the impact of a new Caspian invader Mnemiopsis leidyi A. Agassiz, 1865 on marine and anadromous fish species. The introduction of the ctenophore and its massive development in the Caspian Sea have mainly affected planktophagous fish, especially the most abundant species anchovy sprat (Clupeonella engrauliformis Borodin, 1904) and sturgeons (Family Acipenseridae). Mnemiopsis leidyi is one of the main negative factors preventing the restoration of the populations of Caspian fishes, especially anchovy tyulka. The critical state of the resources of the spawning parts of sturgeon populations (Family Acipenseridae) has been reinforced as a result of the massive development of M. leidyi.

The effect of environmental factors such as water temperature, experimental conditions (fish in control), toxicants (heavy metals, herbicides, insecticides, etc.), and features of physiological state (starvation, early ontogenesis, reproduction, and relationship) on the activity and content of lysozyme in serum/plasma and some immune organs in fishes of the family Cyprinidae have been reviewed. Similar and multidirectional reactions of the enzyme under the influence of the same factors, as well as a wide range of variation, various units, and dimensions of the studied parameter of nonspecific resistance, have been shown. This review presents research materials that have been published in the past 15 years.

The separate and combined effects of chronic 30-day exposure to the herbicide Roundup in a sublethal concentration of 2 μg/L and an increase in water temperature at a rate of 8°C/h on the parameters of red and white blood in juveniles of Amur sleeper Perccottus glenii Dybowski have been studied. The ratio of mature and immature erythrocytes in the peripheral blood do not change under the influence of the studied factors. An increase in temperature after chronic exposure to Roundup leads to a decrease in red blood cell sizes and increase in the share of abnormal cells. Exposure to the herbicide and the rise in water temperature have the opposite effect on the number of amitosis in erythrocytes and the ratio of leucocyte cells; an antagonistic effect is identified under the combined action of the factors. Changes in white blood correspond to a nonspecific stress response; changes in red blood indicate a reduction in compensatory responses to hypoxia.

Concentrations of organochloride pesticides (OCPs) and polychlorinated biphenyls (PCBs) that were obtained in landlocked kokanee salmon (Oncorhynchus nerka kennerlyi) from the Tolmachevskoye Reservoir, Kamchatka, correspond to the levels found in freshwater bodies of background areas around the world. The spatial distribution of PCBs and OCPs in kokanee at the spawning ground and in the deepwater part of the reservoir, as well as its distribution in the kokanee organs, indicate the atmospheric input of contaminants and the ongoing technogenic impact, which was generated during the establishment and operation of the Tolmachevskoye Reservoir. The contaminants that enter from these sources into the water column are incorporated into the food web of the water body. The permissible consumption of kokanee fillet from the Tolmachevskoye Reservoir and caviar from red salmon from the Kuril Lake by population is 10–26 kg and 1.2 kg per year respectively.

The diurnal dynamics of the activity of peptidases in fish larvae by the example of bleak Alburnus alburnus (L.) as the dominant species in the open and protected shallows of the Rybinsk Reservoir has been studied for the first time. Two peaks of enzyme activity in the intestinal mucosa of fish larvae are revealed: morning and night. The data on species composition and daily dynamics of number of fish larvae in the shallows of different types are presented.

The Black Sea snail Lithoglyphus naticoides (C. Pfieffer, 1828) (Mollusca: Gastropoda: Lithoglyphidae) was first recorded in the Uglich Reservoir in the summer of 2013. By 2015, several new local settlements of the snail had been found in the Uglich and Rybinsk reservoirs, indicating its successful naturalization in the Upper Volga basin. Parasitological studies of L. naticoides from these habitats reveal the parthenitae of three trematode species.