The diatom Thalassiosira tealata Takano 1980 has been identified using a scanning electron microscope, as a result of the study of phytoplankton in coastal waters of the Peter the Great Gulf, Sea of Japan, and noted for the first time in the seas of Russia. The T. tealata strain and the nucleotide sequence of the 18S rDNA gene used for molecular genetic analysis were obtained. A detailed description of the species is provided, along with microphotographs and data on its distribution.
For the flora of the Cape Martyan territorial aquatic reserve and the hydrobotanical “Southern Coast of Crimea” region of the Black Sea, the species Dasya hutchinsiae Harvey has been indicated for the first time. Its diagnostic features have been clarified and illustrated. It has been shown that four localities of D. hutchinsiae are currently known in four hydrobotanical regions in the Northern Black Sea region, including three directly off the coast of Crimea. The rarity of the species may be due to its belonging to the category of pulsating elements of the regional flora.
The only large synanthropic colony of the common kittiwake Rissa tridactyla (Linnaeus, 1758), located within the city of Murmansk, has been described for the first time on the Russian coast of the Barents Sea. The data have been provided on the geographic location of the settlement, the number and spatial distribution of birds, and productivity. Some aspects of environmental conditions during the nesting period (food availability, predation, and anthropogenic disturbance) and their possible impact on reproduction are discussed.
The linear dimensions of erythrocytes, their nuclei, and the number of cells and hemoglobin in the blood of the black scorpionfish Scorpaena porcus Linnaeus, 1758 were studied in the autumn–winter period, at water temperatures of 17, 13, 8, and 4°С. The results showed high and relatively equal hemoglobin contents and the number of erythrocytes in the blood of black scorpionfish at 17 and 13°C. However, the studied parameters at a water temperature of 13°С were taken as the physiological norm, since this temperature more corresponded with the autumn temperatures of the Karadag coast. Lowering the water temperature in the aquarium to 8°C reduced the hemoglobin level by 25% and the number of erythrocytes by 26% in the blood of S. porcus. The linear dimensions of erythrocytes did not change when the temperature dropped to 8°C. At a temperature of 4°C the number of erythrocytes and hemoglobin in the blood of S. porcus rapidly decreased by 57% and by 31%, respectively, and swelling of erythrocytes was observed. The large diameter of red blood cells increased by 11% and the small diameter by 25%. The linear dimensions of the nuclei of erythrocytes increased by 12% along the major and minor axes at a temperature of 8°С. At 4°C, the nuclei of erythrocytes decreased in size, along the major axis by 7%, and along the minor axis by 9%, indicating a disruption of the chromatin structure in the nuclear apparatus of the cell. The results we obtained made it possible to carry out a clear gradation of the temperature resistance of S. porcus. At water temperatures below 8°С, destructive processes occurred in the blood, indicating the exhaustion of protective reserves in this species. The data we obtained can be used in fish mariculture as indicators of resistance to temperature factors.
In recent years, marine viruses have evolved into a distinct branch of virology, yet they still represent a sort of “dark matter,” and their role and significance in the evolution and functioning of Earth’s biosphere remain unclear. The widespread implementation of primerless sequencing methods in routine laboratory practice has streamlined the development of marine virology from initial observations of virus-like particles in seawater, once deemed exotic, to comprehensive generalizations that reshape our understanding of global problems in the World Ocean. These include the continuous depletion of biological resources and diversity, marine pollution, and global climate change. Nevertheless, in terms of virology, the World Ocean remains a true aqua incognita, and marine virology, as a subset of general virology, and marine biology are just at the initial stages of their development, standing on the threshold of new discoveries. Those discoveries have the potential to reveal fundamental processes in the origin and evolution of life on Earth, to accelerate the development of novel technologies, and even foster innovative approaches to reshaping the noosphere. The aim of this review is to draw scientific attention to the numerous problematic aspects of viruses in the World Ocean. The review covers the main topics such as the current taxonomy of marine viruses, their role in marine ecosystems, the presence of viruses in marine species and related diseases, and the role of marine viruses in the context of global climate change, focusing on unexplored area and on directions for future research studies.
A comparative assessment of the contents of Fe, Zn, Cu, Cd, Mn, Pb, and Ni in the soft tissues of bivalve mollusks Mytilus trossulus, Mytilus galloprovincialis, and their hybrid forms from Minonosok Bay of Peter the Great Bay (Sea of Japan) has been made. No significant differences in the accumulation of Fe and Cd in the tissues of all studied groups of mollusks were found. It has been shown that the hybrid forms of these species had more intensive growth, and against this background they accumulated significantly lower concentrations of such metals as Cu, Mn, Pb, and Ni in their soft tissues compared to the parental species. A significant negative correlation has been found between the accumulation of these metals in the tissues of mollusks and the length and weight of their shells and whole soft tissues M. trossulus, which had a significantly lower weight of valves and soft tissues, differed from M. galloprovincialis in the accumulation of significantly higher concentrations of Zn, for which no relationship has been found between its content and all the studied size and weight characteristics. The conducted testing did not reveal any significant dependence of the accumulation of all studied metals, with the exception of Pb, in the tissues of mollusks on their condition index. The results we obtained indicate the need to take the above features of the trace metal composition of the soft tissues of the studied species into account when using them in monitoring environmental pollution with heavy metals.
Pilidia from the recurvatum group are usually sock-like larvae and include the following types: pilidium recurvatum, pilidium incurvatum, and pilidium prorecurvatum. The origin of these pilidia remains debated.The external morphology, musculature, and the nervous system of pilidium incurvatum from Nha Trang Bay are described using light and confocal laser scanning microscopy. The morphologies of p. recurvatum and p. incurvatum are not significantly different. Unlike pilidium prorecurvatum, p. incurvatum has a telotroch, two ventral nerves, and a double ventral muscle strand; the nerve and the muscular rings are located close to the telotroch. The Dawydoff’s hypothesis about the origin of pilidia ex gr. recurvatum from a typical hat-like pilidium is supported.
The paper considers the origin of segmentation, tentacles, limbs, and ciliary bands of larvae of Deuterostomia. The analysis of the expression of regulatory genes (along with the data of classical comparative anatomy) allows us to prove the homology of the pharyngeal plane of Anthozoa and the sagittal plane of triploblatic Bilateria and to confirm the origin of the coelomic segments from the peripheral gastric pockets of coelenterone. At the same time, an end-to-end homology of the segments is assumed within the Bilateria. The homology of the preoral segment and the tentacular segment in all Bilateria is emphasized. It is assumed that the ancestors of Bilateria had two circles of tentacles, labial and marginal. The marginal tentacles of the coelenterates are homologous to the metameric appendages of Bilateria, and the labial tentacles are homologous to the perioral ciliated tentacles and the ventral ciliated sole. The ciliary bands of larvae are homologous to the labial ciliated tentacles transferred to the larval stage. Possible homologues of metameric appendages and ciliated tentacles in Deuterostomia are discussed. In chordates (taking into account the “upside-down theory” of their origin), the radials of the median fin are considered as homologues of the labial tentacles, while the radials of paired fins are considered as homologues of the marginal tentacles. Two-phase expression of Hox genes allows us to prove the homology of tetrapod digits and fin radials of primitive fish. The similarity of the genetic mechanisms regulating the development of limbs makes it possible to stretch the threads of homology from the coelenterate tentacles to the limbs of vertebrates.
Rhynchospio glandulosa is a common polychaete living in silty tubes in soft sediments in temperate shallow waters in the Northwest Pacific. Worms are simultaneous hermaphrodites. Spermatogenesis occurs in the coelomic cavity. Spermatids are joined in 16-cell clusters. The spermatozoa have a dome-shaped acrosome 1.2 µm long, an elongated nucleus 2.9 µm long, midpiece 2.4 µm long with subspherical mitochondria, and a flagellum about 44 µm long. The acrosome is a complex structure with five internal parts. The nucleus is concave anteriorly and has a short fossa posteriorly which accommodates the basal body of the axoneme. The flagellum is strengthened by two circles of microtubules in addition to the central axoneme. Oogenesis is intraovarian. Developed oocytes are about 130 µm in diameter, with an envelope about 0.8 µm thick, consisting of three layers of extracellular matrix: the thickest basal layer penetrated by unbranched microvilli each about 0.4 µm long, a homogenous intermediate layer with the highest electron density, and the outer brush-like layer with numerous extensions each about 0.3 µm long. The oocytes are spawned to the parent’s dorsum where they are loosely held by flat branchiae and long dorsal capillaries. In this “hatchery” larvae develop until the four-segment stage, then leave the parent and continue development in sea water. The general morphology of long-headed spermatozoa and thin-envelope oocytes of R. glandulosa is similar to that of other brooding spionids, but the details of their gamete ultrastructure are different.
A study of four-armed plutei (96 h post-fertilization) of a commercially valuable sea urchin, Strongylocentrotus intermedius (A. Agassiz, 1864), showed a significant variability of larvae morphology between technical replicates within a biological replicate. Of the three larval characters studied—length of body rod, length of post-oral arms, and length of body midline—the length of post-oral arms was found to be the most variable in terms of mean and variance values. The relative difference in the post-oral arm length varied from 0.002 to 9.3% between the technical replicates within a cross and considerably differed in 5 out of 20 biological replicates. In contrast, the relative difference in the mean body rod length between the technical replicates ranged within 0.06–4.7%, and the relative difference in the mean body midline length was within 0.12–10.22%. Only one biological replicate showed a statistically significant difference in the mean body midline length between the technical replicates, and none of biological replicates had statistically significant differences in the mean body rod length between their technical replicates. Our results have shown that the degree of variability differs among larval characters. These observations can help estimate the degree of variability in certain characters of sea urchin larvae to be taken into account when planning, analyzing, and interpreting results of experimental studies. This is critical when the expected effect of a treatment is small and can interfere with or masked by the variability in the characters under study.
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