Russky Island (Sea of Japan) urbanization and the necessity to build an artificial channel between Novik and Ussuri Bays

Analysis of long-term data (1987–2019) was carried out on the morphology and autecology of the benthic colonial large-cell species Striatella unipunctata (Lyngbye) C. A. Agardh, 1832 in the microphytobenthos of the Black Sea and Sea of Japan, including water areas of specially protected natural areas of Russia. The species is widely found on natural and artificial substrates in the Black Sea year-round, and in the Sea of Japan, at a water temperature down to −1.5 °C. St. unipunctata quantitative data were determined by direct cell counting in the Goryaev camera under light microscopes (LMs) Biolam L-212, Axioskop 40, and Olympus BX41. Species morphology, phytogeography, and ecology are described. The cell size range of populations is presented: for the Black Sea, valves 25–148 µm long, 8–22 µm wide, frustules 36.3–50.4 µm wide, 18–24 fibulae in 10 µm, and 7–8 girdle bands in 10 µm; for the Sea of Japan, valves 85–125 µm long, 12–21 µm wide, 7–8 girdle bands in 10 µm, 20–25 fibulae in 10 µm, frustules 32.0–34.3 µm long, 10–11 µm wide, and 25 fibulae in 10 µm. For the first time, St. unipunctata valves and frustules were studied in vivo under LMs, and frustule ultrastructure, under a scanning electron microscope (SEM). For the first time, quantitative indicators of the species populations from the Black Sea and Sea of Japan were compared. The morphology of the frustule ultrastructure of St. unipunctata was studied under a Hitachi SEM, model SU3500 (Japan), in Leica EM ACE200 gold-palladium-coated samples. In the Kazachya Bay of the Black Sea near the Oceanarium, the absolute maximum abundance was recorded – 41.6·10³ cells·cm−2 with a biomass of 1.73 mg·cm−2 in January (t = +6.9 °C) in the epizoon of the cultured mussel Mytilus galloprovincialis Lamarck, 1819 at a depth of 0.5 m at excessive organic pollution of water. The minimum values were of 0.26·10³ cells·cm−2 and 0.011 mg·cm−2, respectively, in July (t = +23.5 °C) at a depth of 2.5 m. In the Paris Bay (Russky Island) of the Sea of Japan in the water area of the Marine Mammal Research Base of the Primorsky Oceanarium (Vladivostok), the abundance in the asbestos plates periphyton was of 207·10³ cells·cm−2 in the summer. For the first time, unique micrographs of the species in vivo were obtained under a LM, and of purified frustules – under a SEM.

Taxonomic and quantitative composition of Foraminifera assemblages in the Zhitkov Bay (Russky Island, Peter the Great Bay, Japan Sea) are described. In total, 52 species from 30 genera and 14 families of benthic foraminifera have been identified in bottom sediments. The most of them are represented by calcareous forms (38 species), with the highest abundance of families Elphidiidae, Discorbidae, and Buliminidae, other are 14 species of agglutinated foraminifera, including 2 common species of families Trochamminidae and Ataxophragmiidae. Population density of benthic foraminifera correlates well with the type of bottom sediments: the highest abundance is observed on alenric sediments and pebble-sandy grounds and the lowest abundance - on fine-grained pelitic sediments. Six assemblages of benthic foraminifera are determined for the Zhitkov Bay, taking into account the prevailing families.

The first assessment of the condition of coastal waters around Russky Island, Peter the Great Bay, in the vicinity of Vladivostok, has been made based on the data on concentrations of Fe, Zn, Cu, Cd, Pb, and Ni in the brown algae Sargassum miyabei and S. pallidum collected along the coast of the island in July and August 2016. It has been found that the concentrations of heavy metals in algae from waters off Russky Island mostly exceed their background levels in Sargassum algae from the northwestern Sea of Japan. On the southeastern side of the island, facing Ussuri Bay, which is distinguished by a rocky/bouldery coast and beds of S. pallidum, algae are characterized by lower concentrations of trace elements than those on the other sides.

The profile of infectious agents was studied in individual examination of ticks collected in the south of Primorsky Territory: on the islands of Petra Velikogo Bay in the Sea of Japan (Askold, Popova, Reineke, Rikorda, Russky) and the adjacent mainland territory (Botanical Garden FEB RAS in Vladivostok City). Ticks were collected from vegetation using a flag. On the mainland near the Botanical Garden in 2023–2024, three species of ixodid ticks (Ixodes persulcatus, I. pavlovskyi and Haemaphysalis japonica) were identified, with I. persulcatus predominating. We have shown that, compared to data from the first twenty years of the 20th century, the proportion of I. pavlovskyi in this area has increased from 3 % to 11 %. Five species of ticks were recorded on the islands studied: I. persulcatus, I. pavlovskyi, H. japonica, H. concinna, H. longicornis. Ticks of the genus Ixodes are dominant on Russky and Popov Islands, and Haemaphysalis on Askold Island. In all cases, tick communities are bidominant. Few ixodid ticks were collected due to poor weather on Reyneke and Rikord Islands, preventing a description of the community structure. This study of infectious agents profile in 460 speciments using individual PCR assay from five species (I. persulcatus, I. pavlovskyi, H. japonica, H. concinna, H. longicornis) of ixodid ticks collected in the south region of Primorsky Krai during 2023-2024. Infection with tick-borne encephalitis virus (0,8 %), Borrelia (20,8 %), Ehrlichia (0,4 %), and Anaplasma (1,9 %) was shown. Moreover, сo-infection of individual ticks with two pathogens simultaneously in 0,9 % cases was identified. In addition, tick-borne encephalitis virus and ixodid tick-borne borreliosis pathogens is higher in tick samples from Russky Island in contrast of another Island and on the mainland. Two tick-borne encephalitis virus isolates corresponding to Siberian subtype from ticks of the genus Ixodes that was collected on the Russky Island. One tick-borne encephalitis virus isolates from the I. pavlovskyi tick in Island Ricorda. On the territory of the Botanical Garden and Russian Island three types of pathogenic Borrelia have been identified: the group Borrelia burgdorferi s.l. (B. afzelii and B. garinii) and B. miyamotoi Two species of Rickettsia was identified: Candidatus R. tarasevichiae from I. persulcatus and Candidatus R. principis from the tick H. japonica.

The content and distribution of indicator groups of microorganisms were studied. Biotesting of water and aqueous extracts from bottom sediments of Novik Bay (Russky Island, Peter the Great Bay, Sea of Japan) was conducted. It was established that at the time of observation, the waters of the bay belonged to the category of α-β-mesosaprobic, and the obtained values of the oligotrophic index indicated the accumulation of easily accessible organic matter. The biological pollution of water was indicated by a high number of bacteria of the sanitary indicator group, exceeding permissible standards, and the activity of plant communities was indicated by the presence of large quantities of indicators of phenolic contamination of the environment. Nickel-resistant bacteria stood out in terms of numbers and distribution among the groups of metal-resistant microorganisms, which is due to the combustion of hydrocarbon fuels, confirming the widespread distribution of oil-oxidizing microorganisms. The bioassay showed that water and aqueous extracts from bottom sediments had a depressing effect on the Ph. tricornutum culture in the acute experiment, indicating the presence of pollutants in the environment that are toxic to microalgae. None of the water samples showed any toxic effects on the microalgae culture in the chronic experiment. However, bioassay of aqueous extracts from the soil revealed a stimulating effect, most likely due to the accumulation of organic matter in the bay's soils.

Oceanographic and ecological properties were measured in the Novik Bay of Russky Island (Japan Sea) in early spring (April) of 2023, the indicating groups of microorganisms were examined. Good ecological state of the bay waters was detected. Stable density stratification was already formed, with the water temperature range from 2.3oС at the bottom to 10.0oС on the sea surface and salinity from 33.6 to 31.1, respectively. Dissolved oxygen content was high in the bottom layer (9.6–10.8 mg/L). In the surface layer, the oxygen content was lower, as well as chlorophyll a concentration. Abundance of the colony-forming heterotrophic microorganisms was rather low, so the waters of the bay were characterized as oligosaprobic and pure that indicated accumulation of easily accessible organic matter (accumulation predominated over destruction), apparently due to development of production processes. Some exceptions with zero balance between the production and destruction were found in the Trud Inlet, in the inlet of Sports Club, and at Podnozhye village. Bacteria of the sanitary-indicative group were recorded in small quantities at two stations where they indicated biological and fecal pollution of the water. Microorganisms growing on media with crude oil were observed everywhere, although their number was not high, so the waters of the Novik Bay were identified as low-polluted, in general. However, high abundance of phenol-resistant microorganisms at most of the stations was a signal of significant pollution by phenols, that could have both natural and anthropogenic sources. Metal-resistant microorganisms were not abundant in the surface layer that showed the minimal level of technogenic pressure. Their dominant group was Ni-resistant heterotrophs associated with combustion of hydrocarbon fuel.

Method of thermal induction was tested for the first time in the practice of Far Eastern aquaculture to obtain polyploid Pacific oyster Crassostrea gigas. Experimental blocking of meiosis was performed 25 min after fertilisation by brief (3 min) exposure to the temperature of 32 oC. Efficiency of the method was evaluated with assessment of survival, growth and development of control and experimental larvae (groups 2N and 3N, respectively) in conditions of plant. Growth rate of juvenile Crassostrea gigas in Voyevoda Bay, Russky Island (Peter the Great Bay, the Sea of Japan) during two years was studied also. The content of DNA in haemocytes evaluated using flow cytometry revealed 35% triploids, 22.5% tetraploids and 40% heteroploids in the group 3N. The maximum weight increment in this group (0.34 g/day) was observed in summer at the second year of life, and the maximum linear growth rate (1.55 mm/day) – in September at the second year. The values for the group 2N were 0.31 g/day and 1.47 mm/day respectively. After 22 months, 57.9% of diploid and 80.9% of polyploid oysters reached their commercial size. The total weight of oysters in the group 3N was 124.6 ± 2.7 g, what was 43% more compared to the group 2N.

Seasonal Features of the Novik Bay Hydrological Regime (Russky Island, Peter the Great Bay, Sea of Japan)

Purpose. The paper is aimed at studying the hydrological regime of the Novik Bay (Russky Island, Peter the Great Bay, Sea of Japan). Methods and Results. Regular ship and ice cover CTD observations (more 1000 water column profiling stations) carried out in the Novik and Amur bays in 2013–2018 were used. Weather conditions in the region under study were analyzed based on the data of the Vladivostok weather station archive (WMO_ID=31960). Quantitative estimates of the drift and gradient currents in the bay are represented. Conclusions. Seasonal changes in the thermohaline stratification of the Peter the Great Bay coastal waters are conditioned by the monsoon climate features. The Novik Bay hydrological regime is additionally affected by its isolation and shallowness, as well as by the Russky Island relief. Weak water dynamics in the bay is observed during the summer monsoon (April – August) that is a result of the south winds blocking by the hills. The autumn-winter monsoon (when the north winds dominate) induces the water surge to the bay that, in its turn, blocks its circulation. The winter Siberian cold anticyclone forms the ice cover in the bay, and just in such an ice-forming season the salinity increase in the bottom layer is observed. In the shallow southern part of the Novik Bay, the process of ice formation begins. The downwelling flow of salty heavy water directed to the north out of the bay along the bottom relief is compensated by the counter flow of fresh waters from the Amur Bay which inflow to the upper sub-ice layer. The freeze-up period is most favorable for water renewal. The efficiency of this process is additionally influenced by a heat flow from bottom sediments and by the ice conditions in the adjacent water areas of the Peter the Great Bay

The morphologies of two species of Skeletonema Greville from Paris Bay (Russky Island, the Sea of Japan) were studied by light microscopy and transmission electron microscopy. The examined species were identified as S. grethae and S. japonicum; their occurrence in the seas of Russia was recorded for the first time. Detailed morphological descriptions are given for each species. The study of the development of S. grethae and S. japonicum in laboratory culture revealed differences in their life cycles.

Eleven polyketides that have been tested in laboratory and field conditions as growth stimulants of the spring barley (Hordeum vulgare L.) were educed from marine fungus Penicillium thomii Maire KMM 4675, which was obtained from mycobiota of the brown seaweed Sargassum pallidum (Novik Bay, Russky Island, Sea of Japan). Depending on the chemical structure, polyketides have different effects on the growth of barley sprouts. It is shown that the compounds pallidopenilline A, 1-acetoxy-pallidopenilline A, 1-deacetyl- pallidopenilline B, pallidopenilline E, pallidopenilline F, and pallidopenilline H have a stimulating effect on the growth of sprout roots (from 2 to 24%) and the compounds pallidopenilline A and 1-acetoxy-pallidopenilline A stimulate the productivity of the spring barley at concentrations of 1.0 μg/mL (17.1%) and 10.0 μg/mL (19.5%), respectively. Pallidopenilline A and its acetylized derivative 1-acetoxy-pallidopenilline A showed the maximum stimulatory effect (24 and 10%, respectively) on the growth of barley sprouts at a concentration of 0.01 μg/mL. Pallidopenilline A is recommended for wider use in the field conditions as a growth stimulant.

In this study, otolith shape analysis has been used to perform identification of two smelt species specimens (genus Hypomesus), H. japonicus and H. nipponensis, as well as differentiation of local gatherings in the first species, in the north-western Sea of Japan (SJ). Based on the otolith shape and using several multidimension statistical approaches obvious differences were defined for both inter- and intraspecies levels of otolith variation. Species discrimination by otolith shape indices and other variables extends well to within the species H. japonicus gatherings, the individuals sampled from the northern sample in Olga Bay (OB) are most similar morphologically to those from the coastal waters off the village of Terney to the north of OB. In contrast, the individuals of this species from the coastal waters off Russky Island (RI), including another southern sample and those from northern samples, manifest the greatest differences, thus providing evidence on the existence of at least two local stocks of the species in the waters of the north-western Sea of Japan.

Experiments were carried out on intravital otolith-tagging of juveniles of the ocellated blenny after transition to benthic life mode with Alizarin Red S. Marking at a dye concentration of 200 mg/L for 16–18 h at night, gave 100% formation of fluorescent marks with zero mortality of experimental individuals. Alizarin marks on the otoliths correspond to “stress” marks in the form of darker micro-increments, visible in transmitted light. The calculation of microincrements in the zone between two consecutive markings with an interval of 9 days confirmed the daily periodicity of their laying at this stage of development of the ocellated blenny. This allowed us to determine the period of hatching in natural conditions of juveniles in the Zhitkov Bay (Russky Island, the Peter the Great Bay, Japan sea). Hatching of larvae in 2017 in this species occurred, according to our estimates, from the last decade of March to the end of the second decade of April, with a peak in the first decade of April. Hatching begins even under the ice at a slightly negative water temperature of –1–0°C, but it proceeds mainly already at a temperature of 1–3°C, after the removal of ice from the bay. Taking into account the known timing of spawning of the ocellated blenny in the Peter the Great Bay (November–early December), we can state that the development of its eggs in this area is greatly slowed down at water temperatures below zero in December–March and can go on for 4–5 months, which is almost 3 times longer than the development time in more mild conditions of the south Hokkaido.

Chemical and ecological state of the Novik Bay waters is described on the data of surveys conducted in summer, autumn, winter, and spring of 2014-2015. Lowered content of dissolved oxygen is noted for summer, with occasional decreasing to 5-6 mg/L that is below the standard summer value for fishery ponds. However, the oxygen content restores quickly in autumn, up to 12 mg/L, that is conditioned by hydrodynamic activity, water temperature decreasing, and phytoplankton blooming. The latter process is confirmed by high values of BOD 5 (4.44-5.58 mgO 2 /L) in autumn. Winter conditions under the sea ice are satisfactory for marine organisms: dissolved oxygen content is > 4 mg/L in the whole water column that is close to the standard winter value for fishery ponds.

First data on concentrations of Fe, Zn, Cu, Cd, Pb, and Ni in brown algae Sargassum miyabei and S. pallidum in the coastal waters at Russky Island in Peter the Great Bay near Vladivostok are presented on the samples collected in July-August, 2016. S. pallidum that covers rocky southeastern coast (faced to the Ussuri Bay) is less polluted by the metals than the algae from other coasts of the Island. However, the elements concentrations in the algae at Russky Island, in general, mostly exceed their background levels for Sargassum algae in the northwestern Japan Sea.