The primary production of Amursky Bay (Sea of Japan) in the summer of 2008

In July 2015, the assimilation number (An) of phytoplankton in Amursky Bay was measured using optical dissolved oxygen sensors (Rinko). The primary production (PP) in the photic layer of Amursky Bay was calculated based on the measured An and chlorophyll vertical profiles obtained during a hydrochemical survey on August 23?28, 2008. The total production in the bay at that period was 840 tC/day. During a phytoplankton bloom, the excess production of biomass leading to the hypoxia of the bottom water was estimated to be approximately (1.0?2.0) × 10³ tC/day.     

Flora of planktonic microalgae of Amursky Bay, Sea of Japan

Long-term studies of the species composition of phytoplankton in Amursky Bay (Sea of Japan) carried out during the period from 1991 to 2006 revealed a total of 357 species of planktonic microalgae from eight divisions: Cyanophyta (8 species), Chrysophyta (8), Bacillariophyta (157), Cryptophyta (5), Dinophyta (143), Raphidophyta (3), Euglenophyta (11), and Chlorophyta (22 species). An annotated checklist of species is presented. In comparison with the late 1960s and early 1970s, the species richness of phytoplankton increased markedly; a greater number of bloom-forming species was recorded.     

Seasonal Dynamics of the Diatoms of the Genus Chaetoceros Ehrenberg in Amursky Bay (Sea of Japan)

The qualitative and quantitative composition of the Chaetoceros Ehr. species was studied in Amursky Bay (Sea of Japan) from January 1996 until May 1998. In all, 30 species, 1 variety, and 1 form of this genus were registered. The species Chaetoceros occurred in plankton throughout the year at a water temperature of –1.8–25°C and a salinity of 11–35. The numbers of Chaetoceros species varied between 100 and 1071000 cells/l, and the biomass varied between 0.9 × 10^–3 and 3.3 g/m³. The numbers were maximum in summer and minimum in the beginning of spring. The Chaetoceros species comprised 45–70 and 5–18% (winter), 68–98 and 65–95% (spring), 50% (summer), and 20% (autumn) of the total phytoplankton numbers and biomass. Six dominant species and 1 variety of Chaetoceros were found. Seasonal complexes formed by the Chaetoceros species were identified and described.     

Pelagic larvae of bivalve mollusks of Amursky Bay,Sea of Japan

Larvae of 63 Bivalvia taxa were found in Amursky Bay. Of these, 47 were identified to the species level. Larvae of 55 taxa were found throughout the bay. The highest species diversity was recorded in the northeastern part and in the center of the southern part of the bay, as well as at the exit from it. Larvae of Mactra chinensis, Mytilus coruscus, Crassostrea gigas, Teredo navalis, Mya japonica, and Mysella ventricosa were widely distributed in the bay. The maximum numbers of species were observed in July and September. A comparison of species lists using the set-theory method showed that the species complexes typical of different parts of Amursky Bay are formed under the influence of the Razdolnaya River runoff flow from the north and marine waters coming from the south. The mean density of larvae during the observation period was 1100 specimens/m³ in the northern and 735 specimens/m³ in the southern part of the bay. The highest density of larvae in Amursky Bay was observed at the end of June, the beginning of July, and in September; the minimal larval density occurred in April, May, and August. While the species diversity was similarly high, the density of larvae was significantly higher in Amursky Bay than in the nearby Ussuriisky Bay.     

Research of interrenal and chromaffin glands in barfin plaice Liopsetta pinnifasciata from Amursky Bay (Peter the Great Bay,Sea of Japan)

Studies of the barfin plaice Liopsetta pinnifasciata inhabiting Amursky Bay (Peter the Great Bay, Sea of Japan) performed in 1999–2005 showed a twofold reduction in the area of cell nuclei of the interrenal and chromaffin glands after 2001, which indicates a significant weakening of the damaging effect of the environment on fish. It is assumed that one of the main causes of the hypertrophy of both glands in barfin plaices before 2001 was the phenolic pollution of the environment. The study points to the sensitivity of the adrenal system of the barfin plaice to changes in the quality of environment.     

Production and hydrochemical characteristics of ice,under-ice water and sediments in the Razdolnaya River estuary (Amursky Bay,Sea of Japan) during the ice cover period

Production and hydrochemical characteristics of ice, under-ice water, and sediments in the Razdol’naya River estuary (Sea of Japan) were studied during the ice cover periods of the years 2007 and 2008. In 2007, snow cover was absent until mid-February and PAR levels under ice were sufficient for the development of phytoplankton. The chlorophyll a content in ice, under-ice water, and surface sediments was high, while nutrient levels were decreased. After a snowfall, the chlorophyll content in ice and under-ice water decreased sharply. In winter 2008, snow cover was formed immediately after freeze-up; therefore, PAR levels in the ice and under-ice water were significantly reduced. The chlorophyll content was lower, but nutrient levels were higher than in 2007. In both winter seasons, the greatest portion of chlorophyll (up to 85%) was contained in surface sediments. Diatoms were dominant in ice and under-ice water. In the absence of snow, primary production at the end of ice cover period may reach 1 g cal/(m² day). With snow cover present, this index was markedly reduced.     

Macrofouling of the Scallop Mizuhopecten yessoensisin the Polluted Area of Amursky Bay, Sea of Japan

The fouling structure of the Japanese scallop was studied in Amursky Bay near Vladivostok. Fifty-six species of hydrobionts were identified. Barnacles prevailed in biomass and population density, and algae dominated in the number of species. The change in the dominant barnacle species observed in the fouling was caused, apparently, by the reproductive strategy of Hesperibalanus hesperius, which is more labile than that of Balanus rostratus, and by the anthropogenic impact on the ecosystem of the bay. The fouling was marked by bivalve and sea anemone species resistant to silting and pollution. The main groups of epibionts were classified as suspension feeders, and as selective detritophages that are characterized by their type of feeding. The total infestation of shells of the Japanese scallop by boring polychaetes and the depressed condition of most mollusks and algae evidenced the unfavorable ecological situation in the area surveyed.     

Vertical distribution and cellular heat resistance of bottom animals from the Possyet Bay (Japan Sea)

Summary 1. Investigations on 15 mass species of bottom animals (Bivalvia, Gastropoda, Asteroidea, Ascidia), performed by means of aqualungs in semi-enclosed bays of the Possyet Bay (Peter the Great Bay of the Japan Sea), have revealed a clear zonality in their vertical distribution. This finding is in contrast to the situation found near islands and capes of Peter the Great Bay, where species distributions are weakly connected with depth, but to a considerable degree determined by the nature of substrate, degree of tides and presence of predators.2. These differences may be explained by differences in summer temperature conditions, considerable decrease of the temperature gradient with increase of depth in semi-enclosed bays, insignificant surface temperature differences and, in depths of about 20–30 m, by intensive water mixing near islands and capes.3. Comparison of the vertical distribution of species from the Possyet Bay with their cellular heat resistance (species-specific feature, used for characterizing genetic heat adaptation) reveals conformity between these indices.4. These results and literature data suggest that the differences in vertical distribution of the bottom invertebrates living in coastal waters are the result of the species-specific adaptation of their cells to environmental temperature; differences in protein structure of different animals are considered to provide the basis of this phenomenon.

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Vertikalverbreitung und zelluläre Hitzeresistenz von Bodentieren aus der Possjet-Bucht (Japanisches Meer)

Kurzfassung Die vertikale Zonierung verschiedener benthonischer Tiere, die in halbgeschlossenen Buchten des Japanischen Meeres untersucht wurden, weicht von den im gleichen Gebiet an Inseln und Steilabhängen festgestellten Tiefenverbreitungen ab. Diese Unterschiede können von der Art des Substrats, der Gezeitenwirkung, den Strömungsverhältnissen und insbesondere von den Temperaturbedingungen abhängen. Ein experimenteller Vergleich der zellulären Hitzeresistenz von Cilienepithelien verschiedener Muschel- und Ascidien-Arten und deren Vertikalverbreitung konnte vor allem den Einfluß der Temperatur deutlich machen. Es wird die Schlußfolgerung gezogen, daß artspezifische Anpassungen an die Umgebungstemperatur, die offensichtlich auf Unterschieden in der Proteinstruktur beruhen, die Vertikalverbreitung von Bodentieren entscheidend mitbestimmen.

     

Diatoms from surface sediments of Amurskiy Bay,Sea of Japan

The results of a study of diatoms from surface sediments (0–1 cm) of Amurskiy Bay are presented for the first time. The specific composition (221 species and intraspecific taxa) and ecological structure of the diatom flora were determined. The diatom species composition of phytoplankton, periphyton, and surface sediments is compared.     

Allozyme Diversity among Different Size Cohorts of Spat of Mytilus trossulus (Bivalvia,Mytilidae) Dwelling together in Amursky Bay,Sea of Japan

Allozyme variability in 16 polymorphic loci in two size cohorts of large (30.0 ± 6.3 mm) and small (9.8 ± 2.3 mm) spat of the mussel Mytilus trossulus (Gould) coinhabiting the intertidal zone in Brazhnikov Bay (Amursky Bay, Sea of Japan) was studied 1988–1989. It was determined that the size cohorts compared were highly similar genetically; Nei's minimum distances were 0.014 and 0.016 in 1988 and in 1989. However, statistically significant differences in allele frequencies were found at 2 loci, both in 1988 and in 1989. The loci differing by allele frequencies in 1988 did not coincide with those in 1989. Significant differences by heterozygosity between the cohorts were found only at the Idg-1 and Est-3 loci, 1988; and at the Aat-1, 6-Fgd, Est-3 loci, 1989; but the average heterozygosity was not significantly different in the cohorts for both years. A deficiency of heterozygotes (Dg) was observed almost at all loci in both cohorts. The mean Dg values were significantly higher in the cohort of small size individuals. Since the environmental conditions for both cohorts were similar, the allozyme differences between them were not a result of natural selection. A possible cause of the allozyme and size differences among the mussel cohorts is the gap in the settling time of larvae, which entails the formation of two size cohorts of mussels. Such a gap was caused by protraction of spawning period of M. trossulus and by the formation of segregate larval pools from various mussel populations differing in allele frequencies.     

Marine fungi in sediments of the Sea of Japan (Russian territory) and their biologically active metabolites

The most abundant marine fungi encountered in various regions of the Sea of Japan belong to the genera Penicillium, Aspergillus, Wardomyces, Trichoderma, Chrysosporium, and Chaetomium. Facultative marine fungi of the genera Scytalidium, Verticillium, and Oidiodendron and obligate marine fungi of the genus Dendryphiella are much less abundant. The composition of marine sediments and the anthropogenic load on them were found to influence the abundance and species diversity of fungi, as well as the occurrence of fungal strains producing hemolytically active substances. The biodiversity of mycobiota and the abundance of hemotoxin-producing fungi in marine sediments may be used to evaluate the anthropogenic load on marine biocenoses. Hemolytic compounds were produced by 57% of the fungi isolated from marine sediments. The hemolytic activity of Chaetomium spiculipilium was revealed in the fraction of the culture liquid containing extracellular fatty acids and pigments. The fatty acid composition of this marine fungus was determined.     

Distribution and Seasonal Dynamics of the Abundance of Centropages abdominalis Sato and C. tenuiremis Thompson et Scott (Copepoda) in Amursky Bay, Sea of Japan

The distribution and seasonal dynamics of Centropages abdominalis and C. tenuiremis (Copepoda) in Amursky Bay (Sea of Japan) were studied from May through November 1991. C. abdominalis occurred in plankton from May through August and in November, with a peak density of more than 40000 specimens/m³ in June, at a temperature of 15–18°C. C. tenuiremis occurred from late June through November, with a maximum total density of 6900 specimens/m³ in August, at 23°C. During the observation period, the distribution of species in the bay was irregular due to the hydrological regime and sanitary conditions of water.     

The Meroplankton of Amurskii Bay (Peter the Great Bay,Sea of Japan)

Russian Journal of Marine Biology - The composition and seasonal dynamics of meroplankton in Amurskii Bay (Sea of Japan) were studied for the first time. The total survey period exceeded two years....     

The distribution of cirripede larvae (Cirripedia: Thoracica) in the Amursky and Ussuriisky bays of the Sea of Japan

Based on data from plankton surveys that were carried out in the waters of the Amursky and Ussuriisky bays of the Sea of Japan from May to October 2007 and 2008, the species composition, time of occurrence, density, and distribution of cirripede larvae (Cirripedia: Thoracica) were studied. The larvae of five species of this group were revealed. Their average density does not exceed 400 ind./m3 and their proportion in the total meroplankton does not exceed 22%. In the summer season, the larvae of Amphibalanus improvisus prevailed and in the autumn season the nauplii of Balanus rostratus prevailed. The number of larvae of barnacles was higher in Amursky Bay, with deep-sea species nauplii being concentrated in its central part and shallow water ones in the northern and central parts, in the zones of costal gyres. In Ussuriisky Bay, the density of larvae of most species decreased seaward from the coast. The abundance of larvae of invasive species A. improvisus show that it has successfully become naturalized in Amursky Bay and is gradually replacing the native species Chthamalus dalli and Balanus crenatus in the lower littoral and upper sublittoral zones.     

An autumn bloom of diatoms of the genus Pseudo-nitzschia H. Peragallo, 1900 in Amursky Bay, the Sea of Japan

A bloom of potentially toxic diatoms of the genus Pseudo-nitzschia was observed in October?CNovember 2005 in the northeastern part of Amursky Bay in the vicinity of Vladivostok (northeastern Sea of Japan) at a salinity of 31?C33.5?? and a water temperature of 6?C12°C. The most intense peak of Pseudo-nitzschia spp. cell density (with a mean value of 1428.9 thousand cells/liter), which was recorded in the second half of October after heavy rains, was mainly caused by the massive development of P. multistriata (67% of the total density) and P. calliantha (9%). A negative correlation was found between Pseudo-nitzschia spp. cell density and water salinity and NH4 concentration; a positive correlation was observed between diatom population density and water temperature.     

The development of Porphyridium purpureum (Bory de Saint-Vincent) Drew et Ross, 1965 (Rhodophyta) from Amursky Bay,Sea of Japan,in a laboratory culture

The growth of the microscopic red alga Porphyridium purpureum was experimentally studied in different culture media and at various levels of water salinity. The ability of this species to recover after cryopreservation was analyzed. It was revealed that the growth rate and generation time of P. purpureum during the exponential growth phase did not significantly differ between cultures on f medium and those on Goldberg’s medium. The species has been found to withstand salinity variations ranging from 8 to 32 vol %. Cryopreservation of P. purpureum cells using three-step freezing with trehalose as a cryoprotectant showed that the dynamics of cell density after thawing insignificantly differed from the control ones.     

The Vibrioflora of Hydrobionts and Waters of the Sea of Japan (Peter the Great Bay) and the South China Sea (Nha Trang Bay)

Russian Journal of Marine Biology - Strains of Vibrio spp. isolated from samples of water and aquatic organisms of the temperate (173 strains) and tropical (124 strains) climatic zones...     

Discards in bottom trawl fishery in the Aegean Sea (Izmir Bay,Turkey)

Sampling was carried out on a seasonal basis during 2007–2009, using a conventional bottom trawl net with 44 mm codend mesh size in Izmir Bay, Aegean Sea. A total of 116 valid hauls: 27 in autumn, 28 in winter, 35 in spring and 26 in summer, were conducted at depths ranging from 30 to 70 m. A total of 112 species: 15 Chondrichthyes, 83 Osteichthyes, 11 Cephalopoda and 3 Crustacea were obtained in the trawl codend. All captures were separated into commercial (C) and non‐commercial (NC) species. The C ratio was 69.6%, while NC (i.e. discards) was 30.4%. Diplodus annularis was the most abundant species in all seasons, followed by Mullus barbatus, Merluccius merluccius, Citharus linguatula, Serranus hepatus, Lepidotrigla cavillone, Spicara maena, Myliobatis aquila, Diplodus vulgaris, and Trisopterus minutus in decreasing order of abundance. These top ten species constituted 75% of total catch weight. Biomass ratios of total discards to commercial species were 0.44 : 1.