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The genetic variation in the breeding concentrations of spotted seals (Phoca largha) inhabiting the Rimsky-Korsakov Archipelago (Peter the Great Bay, Sea of Japan) was studied using the control region of the mitochondrial genome. A total of 17 haplotypes in the control region and adjacent threonine and proline tRNA genes of 535 bp were identified in 32 largha underyearlings. The haplotype network revealed two mitochondrial lineages of spotted seals separated by fixed mutation steps. An analysis of molecular variation (AMOVA) and phylogenetic reconstruction showed significant genetic differentiation between two groups of individuals from the same pupping sites. The obtained results are compared with available data for other parts of the spotted seal range. Possible events in the last glacial that have led to the sympatry of distinct spotted seal lineages in Peter the Great Bay are discussed. [ABSTRACT FROM AUTHOR]

One specimen (38.3 mm SL) of Neoclinus lacunicola Fukao, 1980, belonging to the family Chaenopsidae, was first recorded from Ulleung Island, Korea (East Sea, otherwise known as the Sea of Japan) on 5 January 2021. This species was characterized by paired external pores of incomplete lateral line running from the upper margin of the opercle, seven pairs of supraorbital cirri arranged in two rows, occipital region with a pair of cirri, and 13 rays of pectoral fin. This species is morphologically similar to the Neoclinus toshimaensis Fukao, 1980, but differs in the number of cirri on the supraorbital (6--7 versus 9--11 cirri). This study documents the first report of N. lacunicola in Korean waters and proposes the new Korean name of 'eol-lug-bi-neul-be-do-la-chi' for the species. For the confirmation of the identity of the species, a partial gene sequence of the mt COI (570 bp) of N. lacunicola was obtained for the first time. [ABSTRACT FROM AUTHOR]

Marine gastrotrichs of the Pacific Ocean are poorly known. Here, we report on the finding of a marine chaetonotid gastrotrich of the genus Diuronotus from an intertidal beach within the Sea of Japan in Hokkaido (Japan). The Japanese individual shows a very close resemblance to Diuronotus aspetos. This new record is a consequential extension of its biogeographic range; previous records for representatives of this genus are confined to West Greenland, the North Sea and the east coast of North America. This rarely encountered, but seemingly widespread genus of marine gastrotrichs exemplifies our limited understanding of meiofaunal diversity and distribution patterns caused by sampling bias and insufficient knowledge on nominal species complexes. [ABSTRACT FROM AUTHOR]

We present the results of gas-geochemical surveys in the sea surface water layer, water column, and bottom sediments of the Tatar Strait (north of the Sea of Japan) in 2012, 2014, 2015, 2017, and 2018. The distribution of methane fluxes at the water-atmosphere interface is examined, and its relationship with the geologic structure of the Tatar Strait area is discussed. Methane emission has been revealed throughout most of the Tatar Strait area. The most intense methane fluxes at the water-atmosphere interface, up to 482 mol/(km2×day), are observed on the gas-bearing southwestern shelf and on the gas hydrate slope of Sakhalin Island. The high concentrations of methane in seawater and the high contents of methane, hydrogen, and helium in the shelf and slope bottom sediments are probably due to the seismotectonic activity in the region, the presence of gas hydrates, gas concentration zones, gas migration channels, and the regional deep structure. Application of the model for calculation of the flux and impurity transfer fields to the studied water area has shown high methane emission from the sea surface in areas of vertical gas migration from lithospheric sources. The contribution of hydrodynamic factors to the formation of such zones of high methane emission is less than that of geologic factors. The obtained data on methane flux at the water-atmosphere interface for a shallow sea gave a detailed insight into the main gas discharge zones in the southern Tatar Strait. [ABSTRACT FROM AUTHOR]

Molecular and morphological methods are used to describe Lernaeodiscus rybakovi , a new rhizocephalan species parasitizing the porcellanid crab Pachycheles stevensii Stimpson, 1858, collected in Russian waters of the Sea of Japan. Molecular analysis of three species, including the new one, confirms the monophyly of the genus Lernaeodicus Müller, 1862 and its recent transfer to the family Peltogastridae. The main morphological features of the new species are also common with characters of the other species of the genus Lernaeodiscus Müller, 1862. Externa of L. rybakovi differs from the well studied Lernaeodiscus porcellanae from the E. Pacific by molecular markers, color and the absence of pronounced marginal lobes. Retinacula on the internal cuticle of L. rybakovi are found in the genus Lernaeodiscus for the first time. Some of the female hosts with adult externae were unusual in also carrying their own eggs on the pleopods, a rare situation among rhizocephalans. The complete larval development in the genus Lernaeodiscus is described here for the first time and includes five naupliar and one cypris instar. The main morphological features of Lernaeodiscus nauplii (the presence of flotation collar, morphology of the frontolateral horns and furcal spines, and the arrangement of dorsal setae on the shield head) are common with those of other known peltogastrid larvae, but also resemble nauplii of Peltogasterella in the presence of naupliar eyes and thin structure of the flotation collar. The sizes of male and female cyprids of L. rybakovi overlap slightly. In summer months, larval sex ratio is male-biased. We briefly review important larval characters in the Rhizocephala. [ABSTRACT FROM AUTHOR]

Polyethylene (PE) and polyethylene terephthalate (PET) are among the most abundant plastics polluting the oceans. However, their environmental fate depends on how they have been weathered. Due to its unique geography, the Sea of Japan is a pollution hotspot where plastics accumulate. In this study, the structures of plastics, having drifted into the Sea of Japan coastline environment, were analyzed with a particular focus on examining polymer crystallization and carbonyl formation; two factors which influence microplastic formation and the adsorption of contaminants onto plastic surfaces. PE in the coastal environment did not show evidence of crystallization, although carbonyl formation did increase. By contrast, PET bottles were shown to not be uniform in structure, with unaged bottles being less crystalline in the neck component compared to the body. Because of this difference, in environmental PET bottles, it was the bottle neck that showed increases in crystallization and carbonyl group formation. [Display omitted] • Beached polyethylene was oxidized, though crystallization was not evident. • By contrast, PET bottles had increases in both crystallinity and carbonyl formation. • PET degradation depends on the bottle part; amorphous parts are more susceptible. • Plastics aged in the environment are not as degraded as those aged in lab studies. [ABSTRACT FROM AUTHOR]

90Sr and 137Cs activity concentrations in surface waters of the Sea of Japan (SOJ) decreased during the period of 1993–2010 with effective half-lives of 18 and 15 y, respectively. The longer effective half-life of 90Sr in the SOJ may suggest a surplus of 90Sr to SOJ surface waters, however, no clear evidence of possible 90Sr source has been found. After the Fukushima Dai-ichi Nuclear Power Plant (FDNPP) accident, temporal variations of 137Cs in the surface water of the SOJ have changed, while 90Sr variations followed the pre-accident trends. The 90Sr/137Cs ratios reveal that increases of 137Cs due to the FDNPP accident continued in surface waters of the SOJ until 2016. • 137Cs and 90Sr are useful tracers for studying processes in the Sea of Japan (SOJ). • Effective half-life of 90Sr in surface water of the SOJ is longer than expected. • 90Sr/137Cs activity ratios help to elucidate oceanic effects of the Fukushima accident. [ABSTRACT FROM AUTHOR]

Four heterochronous spore and pollen complexes (SPC) have been identified in the deposits of the submarine Yamato Rise: SPC-1 (Early Miocene), SPC-2 (the end of Early and the beginning of the Middle Miocene), SPC-3 (Middle-Late Miocene), and SPC-4 (Late Miocene). Pollen of various woody plants dominates in SPC-1; the families of gymnosperms (Pinaceae) also prevail in this complex. The climate was moderate and humid because of the proximity to the water area. The complex SPC-2 differs from SPC-1 in the highly increased role of thermophile angiosperms due to the impact of the climatic optimum between the Early and Middle Miocene. The complex SPC-3 is distinguished by the diversity and predominance of broad-leaved woody plants. Gymnosperms are mainly represented by pine families. The composition of palynoflora points to a dissected relief and the burial of pollen not far from the places of its growth. Gymnosperms with a predominance of the Taxodiaceae family are characteristic of SPC-4. The SPC-4 composition is indicative of humid habitat conditions, marshy shoreland, and pollen burial in places of plants growth. The climate was moderate and humid. Palynological investigation suggests the existence of a dry land in the area of the current Yamato Rise throughout the Miocene. The relief was highly dissected and mountainous in the Early and early Middle Miocene; then, the relief roughness and firm-land area reduced dramatically. [ABSTRACT FROM AUTHOR]

Abstract The concentrations and distributions of polycyclic aromatic hydrocarbons (PAHs) were examined from 2008 to 2014 in the surface waters of the Japan Sea region. PAH concentrations decreased in the Japan Sea and Tsushima Strait; consistent with improvements in atmospheric pollution from Japan. There were no changes in the Korean Strait, suggesting a continual influx of contamination separate from the Japan Sea. At all sites, PAHs in the dissolved phase were greater than in the particulate phase. A separate survey in 2011 studied whether contamination in the Kuroshio current accounted for the contamination in the Tsushima strait and Japan Sea. PAH concentrations increased as waters moved into the Tsushima strait and the Japan Sea, suggesting inputs were local and not from the Kuroshio current. This was however confounded by the greater influence of particulate phase PAHs, which are likely deposited by seasonal desert storms. Highlights • PAHs in the surface waters of the Japan Sea have been decreasing from 2008 to 2014. • PAH composition has shifted from petrogenic to combustion based sources. • PAH concentration and composition between the Tsushima and Korean currents differed. • The Kuroshio current is likely not the source of PAH contamination in the Japan Sea. [ABSTRACT FROM AUTHOR]

Abstract Levels and profiles of naturally produced halogenated bipyrroles (Br 4 Cl 2 -DBP and Cl 7 -MBP), methoxylated tetrabromodiphenyl ethers (6-MeO-BDE47), anthropogenic perfluoroalkyl substances (PFASs) and legacy persistent organic pollutants (POPs) were investigated in the livers of 14 cetaceans from the Sea of Japan and the North Pacific Ocean. The concentrations of Br 4 Cl 2 -DBP (4 to 4900 ng/g-wet), Cl 7 -MBP (16 to 3960 ng/g-wet) and 6-MeO-BDE47 (7 to 190 ng/g-wet) were higher in the order of killer whales > toothed whales > baleen whales. Profiles of PFASs were dominated by perfluoroundecanoic and perfluorotridecanoic acids (10 to 540 ng/g-wet), sum of which accounted for 70% of total measured PFASs. Regional difference was observed for Cl 7 -MBP and PFASs, which were higher in the Sea of Japan, whereas Br 4 Cl 2 -DBP was in the North Pacific Ocean. Specific accumulation pattern of these natural contaminants in cetaceans around northern Japan could help compare the exposure profile of PFASs and POPs among other geographic regions. Graphical abstract Unlabelled Image Highlights • Halogenated bipyrroles and methoxy-PBDEs accumulated in the livers of cetaceans. • Long-chained perfluoroalkyl carboxylates (PFCAs) largely exceeded the sulfonates. • No correlation was detected between natural products and long-chain PFCAs. • Bipyrrole and long-chain PFCA profiles differed in cetaceans from two regions. [ABSTRACT FROM AUTHOR]

Many species of Procellaridae are nocturnal on their breeding grounds, exhibiting reduced activity during fuller moonlight, perhaps to avoid predation by predators that use the full moon to hunt after sunset. Among these nocturnal species, Streaked Shearwaters Calonectris leucomelas have high wing loading and have difficulty taking off--especially with unfavorable wind conditions--thus potentially exacerbating moonlight avoidance. Effects of moonlight and wind conditions on the colony activity of this species, however, is poorly understood. We investigated the phenomenon by counting the departure and arrival of birds, and measuring ambient light intensity, local wind speed, and local wind direction at a breeding colony of Streaked Shearwaters on Awashima Island, Japan. Moon phase and ambient light had no significant effect on the frequency of arrivals or departures. Frequency of departures decreased significantly with increasing wind speed, but no effect was seen on arrivals, and wind direction had no effect on arrivals or departures. Our results indicate that: (1) wind speed may play an important role in Streaked Shearwater takeoff from the colony, and (2) moonlight avoidance is a plastic trait that may diminish in large-bodied shearwaters when few diurnal aerial predators are present. [ABSTRACT FROM AUTHOR]

Gaseous elemental mercury (Hg 0 ) is a prolific and persistent contaminant in the atmosphere. Atmospheric concentrations of Hg 0 were determined from 17 September to 7 October 2015 in the northwest Sea of Japan aboard the Russian research vessel Professor Gagarinsky. Simultaneous measurements of Hg 0 concentrations were performed 2 m and 20 m above the sea surface using automatic Hg 0 analysers RA-915M and RA-915+, respectively. Concentrations ranged from 0.3 to 25.9 ng/m 3 (n = 5207) and from 0.3 to 27.8 ng/m 3 (n = 4415), with medians of 1.7 and 1.6 ng/m 3 , respectively. Elevated Hg 0 was observed during three episodes from 19 to 22 September, likely caused by one or more of the following factors: 1) atmospheric transport of Hg 0 from the west and south-west (from N. Korea, China, and the Yellow Sea region); 2) Hg 0 emission from the sea due to pollution by water from the Tumannaya River; or 3) underwater geological activities. Increased Hg 0 concentration was observed during periods when air masses flowed from the south, and low concentrations were observed when air masses came from the north. A daytime increase of Hg 0 concentrations at a height of 2 m occurred simultaneously with decreasing Hg 0 at a height of 20 m. These diurnal variations suggest that two contrasting processes occur during the daytime in the marine boundary layer (MBL): Hg 0 emission from the sea surface and Hg 0 oxidation in the MBL by active halogens formed by photolysis. [ABSTRACT FROM AUTHOR]

We have first determined the contents of rare-earth elements and yttrium (REY) in four major mineral fractions of hydrothermal sedimentary ferromanganese crusts of the Sea of Japan. It is shown that REY are sorbed mostly by Fe oxyhydroxides (FeOOH). The REY content in the residual aluminosilicate fraction is the second most important factor determining the crust composition. The manganese fractions, composing more than 80 vol.% of the crusts, plays a subordinate role in REY accumulation. The REY pattern of hydrothermal sedimentary crusts in back-arc basins depicts the sum of the REY contents of the FeOOH fraction (hydrogenous) and residual fractions containing the total REY of the products of bedrock disintegration and endogenous (pyroclastic material) and exogenous (desert dust) components. [ABSTRACT FROM AUTHOR]

To study the environmental impact of the assessment technologies for the development of shallow methane hydrate zones in the Sea of Japan, deep-sea amphipods (Pseudorchomene sp. and Anonyx sp.) were collected from a depth of approximately 1000 m and were tested for H 2 S toxicity. At 0.57 mg L−1 H 2 S, all specimens of Pseudorchomene sp. were dead after 96 h, whereas all individuals survived at 0.18 mg L−1. Moreover, Anonyx sp. had a survival rate of 17 % after 96 h at 0.24 mg L−1. A similar toxicity test was conducted with the coastal amphipod Merita sp., a detritivore, and all individuals died within 24 h at 0.15 mg L−1. These results suggested that compared with coastal detritivorous amphipods, deep-sea detritivorous amphipods, which also live near biomats with sediment H 2 S concentrations exceeding 10 mg L−1, showed a higher tolerance to H 2 S. • Deep-sea amphipods collected from CH 4 hydrate zones were exposed to H 2 S. • Anonyx sp. and Pseudorchomene sp. were identified based on molecular analysis. • We were able to transport and experiment on Pseudorchomene sp. • Pseudorchomene sp. not exposed to H 2 S survived for >1 year. [ABSTRACT FROM AUTHOR]

A numerical model was established to reproduce the oceanic transport processes of microplastics and mesoplastics in the Sea of Japan. A particle tracking model, where surface ocean currents were given by a combination of a reanalysis ocean current product and Stokes drift computed separately by a wave model, simulated particle movement. The model results corresponded with the field survey. Modeled results indicated the micro- and mesoplastics are moved northeastward by the Tsushima Current. Subsequently, Stokes drift selectively moves mesoplastics during winter toward the Japanese coast, resulting in increased contributions of mesoplastics south of 39°N. Additionally, Stokes drift also transports micro- and mesoplastics out to the sea area south of the subpolar front where the northeastward Tsushima Current carries them into the open ocean via the Tsugaru and Soya straits. Average transit time of modeled particles in the Sea of Japan is drastically reduced when including Stokes drift in the model. [ABSTRACT FROM AUTHOR]

The geotectonic framework and the evolutionary history of the East Sikhote-Alin area (ESA) need revision in accordance with various geological and petrological evidence gathered in recent years. It has been suggested that the investigated region resulted from the subduction of the Izanagi (Kula) and Pacific oceanic plates that lasted from Late Cretaceous to Late Tertiary; however, only Late Cretaceous intermediate and silicic volcanics enriched in LILE and depleted in HFSE can be interpreted as typical subduction complexes. Changes in the Paleogene (Paleocene to early Miocene) magmatic style of the ESA area reflect variation in the Pacific plate – eastern Eurasian convergence parameter, the termination Late Cretaceous subduction, slab tearing, and injection of the oceanic asthenosphere of Pacific MORB type into subcontinental lithosphere. The Sea of Japan opening began in the Eocene with formation of small rift basins in the Tatar Strait, which accumulated coastal facies. From Eocene to early Miocene the extension zone, affected by oceanic asthenosphere, gradually moved eastward, i.e., to the modern Sea of Japan. The effect of oceanic asthenosphere on the continental margin ended in the late Miocene after the Sea of Japan had opened and new subduction initiated east of the Japan Islands. EM I signature of the late Miocene – Pliocene within-plate basalts is evidence for eastward asthenospheric flow. [ABSTRACT FROM AUTHOR]

We extensively reviewed the macrozoobenthos around Dokdo, Korea, by analyzing metadata collected over the past 50 years. The Dokdo macrozoobenthos was represented by 578 species belonging to 243 families from 12 phyla, where four major phyla (or classes) collectively accounted for 86% to total. Mollusks, arthropods, and cnidarians were semi-equally occurred in intertidal and subtidal areas, while polychetes dominated the subtidal zone. The northern most region of Dokdo had the greatest biodiversity (173 species). The taxonomic distinctness analysis (delta +) indicated a close association between species by region, although the number of species varied greatly. About half of the species did not occur cross the locations (n = 20), indicating strong habitat preferences of Dokdo macrofaunal assemblages. Overall, the diversity of Dokdo was greater than that of Ulleung Island (east coast), but comparable to that of the well-developed tidal flats in the western Korean waters, highlighting its status as a biodiversity hotspot. [ABSTRACT FROM AUTHOR]

Hard fragments (crushed only by a hammer) of manganese deposits differing strongly in appearance from the regional ferromanganese crusts were sampled from depths of 3500–3200 m during the dredging of an unnamed seamount in the Central Basin of the Sea of Japan. Their surface has a black carbonaceous coating; after its removal, the crusts become steel-gray. The specific weight of these crust fragments is 3.35 g/cm3, whereas the regional crusts have a specific weight of < 2 g/cm3. X-ray diffraction analysis showed that the sampled fragments consist of pure pyrolusite. There are also fragments of crusts formed by todorokite and birnessite. All pyrolusite samples have an abnormally high content of Mn (up to 63%). The Mn/Fe ratio reaches 9016. The conclusion is drawn that the manganese crusts formed on this seamount are of hydrothermal genesis. [ABSTRACT FROM AUTHOR]

In the middle of December 2014, a storm surge induced by explosive cyclone struck Nemuro, a city located in Hokkaido, Northern Japan, causing immense damage due to flooding. This explosive cyclone suddenly intensified along the east coast of Tohoku region and remained stationary near the Nemuro Bay due to the atmospheric blocking which existed over the Sea of Okhotsk. In this study, we analyze the moving velocity of explosive cyclones in 1960 to 1999 and they are compared with those of typhoons considered as another meteorological cause for storm surge. Furthermore, we discuss synoptic fields in which explosive cyclones move slowly in Northern Japan utilizing an atmospheric blocking diagnosis method. [ABSTRACT FROM AUTHOR]

New data on geology, geochemistry, and isotope systematics of lavas in the East Sikhote-Alin area, along with earlier published evidence for the Sea of Japan, provide insights into the dynamics of back-arc basins and their role in the tectonic and magmatic history of continental margins. Right-lateral strike-slip faulting, the key event in the Cenozoic history of East Sikhote-Alin, apparently had no relation with the subduction in post-Eocene time. At that time, the Late Cretaceous subduction ended and oceanic asthenosphere with Pacific-type MORB isotope signatures injected into the subcontinental mantle through slab windows. The Sea of Japan opening began in the Eocene with formation of small rift basins in the Tatar Strait, which accumulated coastal facies. During the main Miocene phase of activity, the zone affected by oceanic asthenosphere moved eastward, i.e., to the modern deepwater Sea of Japan. The effect of oceanic asthenosphere on the continental margin ended in the Late Miocene after the Sea of Japan had opened and new subduction initiated east of the Japan Islands. [ABSTRACT FROM AUTHOR]

This paper presents the relations between total length and weight for ten demersal fishes from eastern Korean waters: Alcichthys alcicornis (Steindachner 1881); Cleisthenes pinetorum Jordan et Starks, 1904; Dasycottus setiger Bean, 1890; Gadus macrocephalus Tilesius, 1810; Glyptocephalus stelleri (Schmidt, 1904); Gymnocanthus herzensteini Jordan et Starks, 1904; Gymnocanthus intermedius (Temminck et Schlegel, 1843); Liparis punctulatus (Tanaka, 1916); Lycodes tanakae Jordan et Thompson, 1914; and Pseudopleuronectes herzensteini (Jordan et Snyder, 1901). Fish samples were collected seasonally between 2011 and 2017 using bottom gill net and trammel net. The values of exponents a and b from the weight-length relations (WLRs) were estimated. The WLRs for A. alcicornis, G. herzensteini, G. intermedius, and L. punctulatus were estimated for the first time, and new maximum lengths were recorded for G. herzensteini and L. punctulatus. All the relations between total length and weight were statistically significant (all r2 > 0.937). The values of exponent b, estimated using simple linear least squares of log10-transformed weight and length data, ranged from 2.899 to 3.416. [ABSTRACT FROM AUTHOR]

Luminescence dating has long been used for chronological constraints on marine sediments due to the ubiquitous dating materials (quartz and feldspar grains) and its applicability over a relatively long time range. However, one of the main difficulties in luminescence dating on marine sediments is partial bleaching, which causes age overestimations. Especially, partial bleaching is typically difficult to be detected in the fine grain fraction (FG) of marine sediments. The recently developed feldspar post-IR IRSL (pIRIR) protocol can detect non-fading signals and thus avoid feldspar signal instability. In the current study, fine grains were extracted from a gravity core in the northern Sea of Japan, and the aim is to test the feasibility of using different luminescence signals with various bleaching rates to explore the bleaching conditions of fine grain fraction in marine sediments. The results suggest that the quartz OSL signal and polymineral pIRIR signals at stimulation temperatures of 150 °C and 225 °C (pIRIR 150 and pIRIR 225 ) of FG were well bleached prior to deposition. The OSL ages were used to establish a chronology for this sedimentary core and the resulting age-depth relationship is self-consistent and comparable with radiocarbon dates. We conclude that different luminescence signals with various bleaching rates can be used to test the bleaching conditions of fine grain fraction in marine sediments; and the luminescence dating can be applied to marine sediments with great potential. [ABSTRACT FROM AUTHOR]

We present herewith the relations between total length and weight (LWRs) for 29 fish species from the southern coast of the East Sea (=Sea of Japan), Korea: Conger myriaster (Brevoort, 1856); Coilia nasus Temminck et Schlegel, 1846; Engraulis japonicus Temminck et Schlegel, 1846; Clupea pallasii pallasii Valenciennes, 1847; Coelorinchus multispinulosus Katayama, 1942; Lophius litulon (Jordan, 1902); Zeus faber Linnaeus, 1758; Paracentropogon rubripinnis (Temminck et Schlegel, 1843); Lepidotrigla guentheri Hilgendorf, 1879; Liparis tanakae (Gilbert et Burke, 1912); Acropoma japonicum Günther, 1859; Doederleinia berycoides (Hilgendorf, 1879); Jaydia lineata (Temminck et Schlegel, 1842); Ostorhinchus semilineatus (Temminck et Schlegel, 1842); Sillago sihama (Forsskål, 1775); Trachurus japonicus (Temminck et Schlegel, 1844); Pagrus major (Temminck et Schlegel, 1843); Pennahia argentata (Houttuyn, 1782); Zoarces gillii Jordan et Starks, 1905; Callionymus lunatus Temminck et Schlegel, 1845; Callionymus valenciennei Temminck et Schlegel, 1845; Amblychaeturichthys hexanema (Bleeker, 1853); Amblychaeturichthys sciistius (Jordan et Snyder, 1901); Sphyraena pinguis Günther, 1874; Trichiurus lepturus Linnaeus, 1758; Psenopsis anomala (Temminck et Schlegel, 1844); Pseudorhombus pentophthalmus Günther, 1862; Pseudopleuronectes yokohamae (Günther, 1877); and Cynoglossus robustus Günther, 1873. The LWRs for 12 species are estimated for the fi rst time and new maximum lengths for six species are reported herewith. All of the relations between total length and weight were significant (all r² > 0.938). The values of exponent b, estimated using simple linear least squares of log-transformed weight and length data, ranged from 2.730 to 3.440. [ABSTRACT FROM AUTHOR]

Possible sources of gallium in hydrothermal-sedimentary ferromanganese crusts of the Belyaevsky Seamount (Central Basin, Sea of Japan) are considered. Studies with successive selective leaching have shown that ~ 80% of Ga are present in the manganese fraction. The Changbaishan Volcano ash with up to 35.3 ppm Ga has been found in the marine sediment column located in the immediate vicinity of the Belyaevsky Seamount. This suggests that Ga of the Fe–Mn crusts of the seamount was supplied with the ash of volcanic rocks containing up to 300 ppm Ga. [ABSTRACT FROM AUTHOR]

In the autumn of 2010, contrasting dispersion aureoles of atomic mercury were revealed in the northern Sea of Japan, in the vicinity of the Vityaz’ and Alpatov Rises. Based on the elimination method, the assumption is made that the aureoles resulted from the supply of mercury from hydrothermal or water-gas bottom sources through the sea water column, either in gas bubbles or as a result of diffusion and turbulent mixing. It is inferred that gas-mercury measurements can be used in geological research in sea water areas. [ABSTRACT FROM AUTHOR]

Concentrations of 13 phase-partitioned polycyclic aromatic hydrocarbons (PAHs) in seawater were monitored monthly off Oki Island, Japan, during 2015–2019 to elucidate seasonal variations, main source, and transport pathways of PAHs in the southwestern Sea of Japan. Total PAH (dissolved plus particulate) concentrations in surface seawater at 36°09.0′N, 133°17.3′E (site OK) were in the range 0.49–9.36 ng L−1 (mean 2.77, SD 2.05 ng L−1) with higher levels in summer–autumn, an order of magnitude lower than those in the East China Sea during 2005 and 2009–2011 and about one-third of those recorded in the Sea of Japan in 2008 and 2010. The main sources of dissolved and particulate PAHs were combustion products. Increasing dissolved PAH levels during July–October indicate that the area around southern Oki Island is impacted by PAH-rich summer continental-shelf water transported by the Tsushima Warm Current flowing from the East China Sea. • PAHs in surface seawater exhibited seasonal variation with high levels in summer–autumn. • Combustion products are the primary PAH source for surface seawater. • Seawater is impacted by PAH-rich summer continental-shelf water from the East China Sea. [ABSTRACT FROM AUTHOR]

The annual flow and stock of marine debris in the Sea of Korea was estimated by summarizing previous survey results and integrating them with other relevant information to underpin the national marine debris management plan. The annual inflow of marine debris was estimated to be 91,195 tons [32,825 tons (36% of the total) from sources on land and 58,370 tons (64%) from ocean sources]. As of the end of 2012, the total stock of marine debris on all South Korean coasts (12,029 tons), the seabed (137,761 tons), and in the water column (2451 tons) was estimated to be 152,241 tons. In 2012, 42,595 tons of marine debris was collected from coasts, seabeds, and the water column. This is a very rare case study that estimated the amount of marine debris at a national level, the results of which provide essential information for the development of efficient marine debris management policies. [ABSTRACT FROM AUTHOR]

We collected two subspecies of masu salmon: Oncorhynchus masou masou from four localities (southern Sea of Japan northward to Hokkaido) and O. masou ishikawae from upstream from Ise Bay close to a heavy industrial area. All 209 PCB congeners were analyzed using HRGC/HRMS. PCA ordination of congener concentrations divided data into three groups: (i) ssp. masou from Hokkaido, (ii) ssp. masou from the other regions and (iii) ssp. ishikawae. The highest Σ PCB concentration (40.39 ng/wet wt) was in ssp. ishikawae followed by ssp. masou from southern waters; however the TEQdioxin-like PCBs was highest in ssp. masou from southern water (1.96 pg-TEQdioxin-like PCBs/g wet wt.) due to the high proportion of congener #126 in its complement (#126 has the highest toxic equivalency factor among congeners). There is likely a contamination source offshore in the southern Sea of Japan and/or along the migratory route of ssp. masou. [ABSTRACT FROM AUTHOR]

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The article focuses on Japan-Korea relations as of 2012 as South Korea elected its first female head of state and Japanese voters returned the Liberal Democratic Party (LDP) to power. It says that although the elections caused both heads of state to focus on domestic economic issues, speculations abound on how the relations between the two would evolve, especially with the cooling of relations due to the territorial dispute over Dokdo/Takeshima off the Sea of Japan.

Squamamoeba japonica n. g. n. sp. was isolated and described from marine bottom sediments collected at a depth of ca. 2700 m in the Sea of Japan. Trophic amoebae of this species are elongated and flattened, with a wide anterior hyaloplasm producing numerous ventral subpseudopodia for adhesion to the substratum. The cell coat consists of flat oval scales tightly packed together to form a continuous layer separated from the plasma membrane. Amoebae can form cytoplasmic projections protruding through the scale layer and having tips covered only with the plasma membrane. Small subunit ribosomal RNA gene phylogeny shows that S. japonica forms a long branch in the amoebozoan tree, robustly grouping with the marine strain ‘Pessonella’ sp. PRA-29. Morphological data available for the latter, although scarce, give additional support for the relatedness of both species. The resulting clade comprising the two taxa shows no close relationships to other Amoebozoa and seems to be a novel lineage that developed an ability to temporarily liberate local areas of the plasma membrane from the cell coat independently from Himatismenida, Trichosida, Pellitida and Dermamoeba. [ABSTRACT FROM AUTHOR]

Abstract: For three decades, Iwaishima Islanders have rejected the proposal for a nuclear power plant to be built 3.5km from their home. Located in the Suo-nada Inland Sea, which has miraculously escaped contamination, dredging of sand, or reclamation that damaged the Seto Inland Sea after WWII, the islanders maintain their livelihood by marketing fresh fish and organic produce. Based on studies on the biodiversity and recent interviews, some underlying reasons for their unyielding struggle have come to light: (1) some worked in Fukushima Daiichi NPP, and knew its damaging effects on human health and the bioregion; (2) islanders exchange goods and services, with minimal dependence on cash; and (3) they have revived the 10-century-old Kanmai (divine dance) festival held every 4years. [Copyright &y& Elsevier]

Abstract: Polished sections of ferromanganese crusts on underwater rises in the Sea of Japan were studied with a JXA8100 microprobe analyser. Mineral phases of REE have been detected. They have Ln2O3 chemical composition, where Ln is La–Ce–Pr–Nd, La–Ce–Nd, or, much more rarely, La–Ce and La–Ce–Pr. With regard to the same chemical composition of REE grains in the ore crusts and basalts from Medvedev Volcano, it has been concluded that these REE were supplied during postvolcanic gas–hydrothermal processes. [Copyright &y& Elsevier]

The article focuses on the euphausiid Euphausia pacifica's ontogenetic diet shift in the East Sea (Japan Sea or Sea of Japan). Euphausia pacifica is one of the 4 species found in the region and studies about its morphology seems to be lacking. In the study conducted by the authors, they discovered that lower values of §15N are found in adults compared to values found in juveniles. This discovery reflects that as euphausiid E. pacifica matures, their diet turns detritivorous. According to the authors, the results can be useful in analyzing energy transfer in marine food chains.

Abstract: The eddy-resolving Japan Sea (East Sea) data assimilation affects the mid-level troposphere via vertical wind in the early stage of an explosively developing extratropical cyclone on 5–8 November 2006, and its influence further propagates toward the subpolar and polar regions. Two types of atmospheric responses (convective and gravity-wave patterns) to a sea surface temperature (SST) difference resulting from the ocean data assimilation are found in the early stage of the cyclone development over the western and central Japan Sea. A gravity-wave (convective) pattern appears when the near-surface atmosphere is stable (unstable). The atmospheric signals induced by the SST anomaly resulting from assimilation of the ocean circulation model are subject to advection and can deform with time owing to nonlinearity and instability. The differences in atmospheric and surface temperatures are widely and rapidly spread over the polar region by strong synoptic-scale cyclonic advection. On the other hand, the SST effects on vertical flow and precipitation are limited to narrow areas around the northern Japan Sea and the Pacific cold front in the fully developed stage. Such a developing cyclone is potentially important as a transporter of the meteorological influence over the Japan Sea toward the polar region. [Copyright &y& Elsevier]

Abstract: The distribution of Staphylococcus aureus and Listeria monocytogenes in the sea water and marine organisms of Peter the Great and Nha Trang bays, the phenotypic properties and antibiotic sensitivity of the isolates were studied. S. aureus was recorded from 9.3% samples in the Sea of Japan and from 20.4% samples in the South China Sea, L. monocytogenes respectively from 5.9 % and 5.8 % samples. S. aureus and L. monocytogenes found in the tropics differed in their phenotypic properties from those found in the temperate zone. Antibiotic resistance was detected in 81.8% and 71.8% of S. aureus strains and in 19% and 71.4% of L. monocytogenes strains respectively from Peter the Great Bay and from Vietnam. The results show that multiresistant strains of S. aureus and L. monocytogenes are widespread throughout Peter the Great and Nha Trang bays and present a hazard to the health of humans and marine animals. [Copyright &y& Elsevier]

The article discusses a study which investigated the natal origin of Pacific bluefin tuna Thunnus orientalis inferred from otolith oxygen isotope composition. The study demonstrated that otolith oxygen isotope values varied from -2.5 to -2.2% between the otolith core for age-0 tuna caught in the Japan Sea, while those caught in the Pacific Ocean varied between -2.8 and-2.2%. It was also observed that the temporal difference in experienced water temperatures produces an earlier increase of otolith oxygen isotope values for tuna caught in the Japan Sea than in the Pacific Ocean.

Abstract: The anthropogenic radionuclides, 137Cs, 90Sr, 108mAg, 239+240Pu, were measured in two Chionoecetes species, red queen crab (Chionoecetes japonicus) and snow crab (Chionoecetes opilio) collected around Japan during 1996–2007. There was no increase in the concentrations of these radionuclides and no large variation of the atom ratio of 240Pu/239Pu during this research period. These results indicated that the source of the radionuclides was not the radioactive wastes dumped by the former USSR and Russia and originated from past nuclear weapon tests. The higher atom ratio in the crab species than that from global fallout would be contributed by the Pacific Proving Grounds close-in fallout. The variability of the concentration of radionuclides in the crab species would result from the variability of the composition and quantity in the diet. However, the decrease in the concentration of radionuclides with sampling depth would depend on the concentration in the seawater and diet. [ABSTRACT FROM AUTHOR]

Abstract: Characteristics of drift and beaching of floating marine litter in the Japan Sea are examined numerically using the reanalysis data of the Japan Sea Forecasting System of Kyushu University. The residence time of model marine litter deployed uniformly over the surface of the Japan Sea strongly depends on the buoyancy ratio. However, almost all litter beaches or flows out through straits within 3years. Experiments with inputs of litter imposed at large cities and the Tsushima Straits as well as river basins of the Japan Sea exhibit a good agreement with beach surveys with regard to country ratios of beached litter along the Japanese coast in cases of lighters. In a case of lighter, almost all lighters originating from Japan beach along the Japanese coast, while almost all lighters originating from a country surrounding the Japan Sea except Japan beach along the coast of that country and the Japanese coast. [Copyright &y& Elsevier]

The article presents a study which assesses the contribution of cold-water octocorals (CWOC) to carbonate production on the Shiribeshi Seamount in the Sea of Japan. It states that remotely operated vehicle (ROV) dive video and Primnoa pacifica specimens that were collected in and prior to 2001 from the seamount were analyzed in the study. It says that the diameter of cross-sections of branches and the carbonate weight per volume of specimens were measured to estimate the weight of the carbonate per colony while the amount of carbonate standing stock (CCS) was calculated through the analysis of CWOC distribution and the specimen data. The study reveals that CWOC fauna is potentially the most important element that contributes to the formation of carbonate sediments or limestone.

The article explores the significant role of extensive hybridization with minimal introgression in the environmental circumstances of Mytilus trossulus and Mytilus galloprovincialis that exists in Hokkaido, Japan. It examines the similarity of the pattern between in other observed geographic locations and in hybridize Mytilus trossulus and Mytilus galloprovincialis. It presents the two independent hybrid zones that has been produced in the country. Furthermore, it describes the genetic structures of the hybrid populations in the southern and eastern cost of Sea of Japan.

The article explores the enzyme activation of the marine yeast collected from the Pacific Ocean and Japan Sea. It discovers that one of the collected marine yeasts from Pacific Ocean cited with high concentration of γ-aminobutyric acid (GABA) which about 7-10 times higher than other marine yeasts. It describes that the isolated Hachinohe No. 6 is discovered to have the largest catalytic activiity among the collected marine yeasts.

Abstract: The concentrations of 129I in seawater samples from two sites (off Sekine and the Toyama Bay) in the Japan Sea were determined by accelerator mass spectrometry. The observed concentrations exceed amounts expected from natural origin and globally distributed fallout due to nuclear weapons testing. Because the fraction of natural origin and global fallout is 2% and 8.9–13.8%, respectively, the residual more than 80% of the concentration must come primarily from nuclear fuel reprocessing plants. This result indicates a rapid distribution of 129I through atmospheric transport on a global scale. The depth distribution of 129I at the Toyama Bay in the Japan Sea shows that the 129I maximum is in the mixed layer and that concentrations decrease with depth. The inventory of 129I in water column is four times higher than that measured in the Gulf of Mexico which has almost the same depth at the Toyama Bay. This higher inventory probably reflects: (1) the rapid water sinking in the Japan Sea, (2) the difference of distance in sampling locations with respect to major 129I releasing plants and (3) the strong increase in emissions from nuclear fuel reprocessing plants after the profile of the Gulf of Mexico was taken. [Copyright &y& Elsevier]

Abstract: Cells of a taxon similar to the type species of Amphidiniopsis, Amphidiniopsis kofoidii, were found during the course of a study of marine sand-dwelling dinoflagellates in Peter the Great Bay, Sea of Japan, Russia. These specimens were examined in detail using light and scanning electron microscopy and were identified as Amphidiniopsis arenaria, a species known so far only from the North Sea, Germany. Morphological variability within the species and details of its sulcal construction are described here for the first time. [Copyright &y& Elsevier]

Tourism behavior decisions usually involve some interrelated choices among activities/trips over time. In this study, we developed a multidimensional timing decision model under the principle of random utility maximization. The derived model not only allows for the temporally varying utility of timing decision, but also incorporates sequential correlation between the neighboring timings. The model can also endogenously specify the sequences of activities/trips as well as heterogeneous preferences about the timing. Using a data collected from 1-day car tourists at a tourism region nearby the Sea of Japan, we empirically confirmed the effectiveness of the derived model in representing the complex decision-making mechanisms of tourism behavior. [ABSTRACT FROM AUTHOR]

A major heavy-oil spill from the Russian tanker Nakhodka occurred in the Sea of Japan on 2 January 1997. We investigated the impacts of this spill on a rocky intertidal ecosystem along the southern coast of the Sea of Japan. We selected Imago-Ura Cove as our study site to observe temporal changes along the oiled shore, because minimal cleaning effort was made in this area. Field surveys were conducted every autumn and spring from 1997 to 2000. We measured coverage by macroalgae in 1×1-m2 quadrats and counted the animals in 5×5-m2 quadrats along the intertidal zone. Changes in the ecosystem caused by the oil spill were analyzed by applying a geographical information system (GIS) to the Sea of Japan for the first time. The GIS showed that following the accident there were heavily oiled areas in sheltered regions, but these decreased over the three years. It also showed that coverage by macroalgae and the number of animals increased, although some species of algae with microscopic sporophyte generations, and some populations of perennial shellfish, remained stable or decreased during the study period. GIS was able to trace temporal changes in intertidal communities resulting from the impacts of heavy oil on flora and fauna at a spatial scale of 10–100 m. GIS is thus a practical tool for visualizing, analyzing, and monitoring changes in an ecosystem polluted by oil, taking into account topographic differences along the coastline. [Copyright &y& Elsevier]

Multivariate statistical analysis of data on environmental variables and benthic macrofauna, of 30 sites from four surveys done between 1986 and 1989 in Amursky Bay, is presented. The purpose of this study is to investigate a contamination gradient, assess effects on benthic fauna and evaluate quantitative and qualitative benthic parameters.Contamination was assessed using chemical data from PCA-ordination analysis. Clear patterns were found using three categories, moderate, severe and gross. Significant changes in the number of taxa, density and ecological indices are observed between severe and moderate levels. Changes in these parameters, excluding the number of species, were also detected between gross and moderate levels. Only biomass differs non-significantly. However results of cluster analysis and MDS ordination indicate that two benthic communities exist in Amursky Bay.The most “contaminant insensitive” species polychaetes are Tharyx pacifica, Dorvillea (Schistomeringos) japonica, Dipolydora cardalia, Capitella capitata, phoronid Phoronopsis harmeri. Contaminant sensitive species include Maldane sarsi, Lumbrineris sp. and Scoloplos armiger. [Copyright &y& Elsevier]

Focuses on a study which examined the species composition and quantitative indices of phytoplankton in the Amur Bay of the Sea of Japan near Vladivostok. Materials and Methods; Results; Discussion.

Provides information on a study that examined seasonal and inter-annual changes in plankton based on the analysis of many samples of plankton taken during some years in various sections of the Japan Sea differing in their oceanological conditions. Methodology of the study; Results and discussion on the study; Conclusion.