Tatar Strait Research Articles

Late Mesozoic and Cenozoic volcanism of the East Sikhote-Alin area (Russian Far East): A new synthesis of geological and petrological data

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.

Некоторые методические проблемы водолазных гидробиологических учетных съемок и пути их разрешения

Methods of SCUBA hydrobiological surveys are discussed on the base of the author’s 18-year experience in the western Tatar Strait (Japan Sea) and in the Okhotsk Sea. Typical errors of the assessments are analyzed. So far as the methods of underwater researches develop actively, there are no universal one in this field. Regular sampling and uniform assessment methods do not guarantee to avoid the errors but usually cause excessive volume of samples and man-hours. Optimal planning of the sampling should be based on statistical analysis of preliminary information about distribution of the assessed objects in the area of survey. Planned number and location of the sections, stations and samples should be adjusted on the spot, if necessary, following the principle of sufficiency for obtaining representative data. The sections should be performed taking into account types of the coast, the stations - in accordance with natural biotic stratification. Sampling tools and methods should be chosen in dependence on nature, size, density, and distribution patterns of the assessed objects and specific conditions of survey. Modern technical means of underwater video surveillance, echolocation and satellite navigation must be involved into practice of SCUBA surveys. Some original sampling tools developed by the author are presented. Their use can significantly reduce the SCUBA man-hours, and in some cases allows to manage without diving. Rational planning and competent conducting multiply effectiveness of SCUBA survey, allowing to reduce its labor and time costs.

On occurrence of northern fur seals in the Tatar Strait (Japan Sea)

Results of observations on northern fur seals in the Tatar Strait are presented. The mammals were observed from the Nevelskoy Strait in the north to Cape Krilyon in the south.

Pacific sardine (Sardinops melanostictus) migrations to the shores of Sakhalin Island in the 20th–early 21st centuries

Historical data for the period 1929−2011 were used to generalize information on the seasonal feeding migrations of Pacific sardine to the shores of Sakhalin Island. In the 20th century, the cyclicity of sardine occurrence in the Tatar Strait and southwestern part of the Sea of Okhotsk appeared to have a similar character. Sardine distribution patterns are considered in connection with the oceanological characteristics on these areas. A close correlated relationship was revealed between the SST anomalies and northern boundary of distribution of this subtropical fish. Besides the water temperature, Pacific sardine northern migrations have been formed under the influence of many other factors (by origin and impact), including fluctuations in abundance, index of stock biomass, food supply, state of marine ecosystems, and climatic conditions.

Latitudinal variations in the composition and structure of vegetation in the northwestern Tatar Strait

The pattern of the latitudinal distribution of the floristic composition and structure of the submerged vegetation cover in the western Tatar Strait (within Khabarovsk Krai) is studied using the published data and original materials. Irregularities of the floristic composition have been found within limited areas of bays in this region, where they do not form any distinct borders or gradients. In the vegetation cover, vice versa, borders and gradients have been shown to form various combinations. The specific biomasses of most of the dominant species are significantly increasing, whereas the width and depth of the vegetation belt decreases from the south to the north. Their regression lines intersect at the latitude of 50° N (Cape Syurkum). Discrete coenotic variations are manifested most clearly as well at this point, where the dominance of Saccharina japonica, observed south of the cape, changes for S. cichorioides north of it. This allows establishing the phytocoenotic border here. The revealed features correspond to the direction of the temperature gradient, as well as to the variations in topical conditions and the level of hydrodynamic load along the coast.

Movements of spotted seals (Phoca largha) in the Sea of Okhotsk according to satellite tagging data

For the first time, satellite tagging of spotted seals (Phoca largha) has been performed in three regions of the Sea of Okhotsk: Chkalov Island in Sakhalin Bay, Ptichy Island, and the Bolshaya River mouth on the western coast of Kamchatka. As a result, regions inhabited by the seals in different periods of their life cycle and differences in the pattern of water area use by animals from different regions have been revealed. The seals from the western Kamchatka coast have covered greater distances during the observation period, compared to the animals from Sakhalin Bay. In the reproductive period, the seals from the western coast spread over the entire northern part of the Sea of Okhotsk, whereas the animals from the Sakhalin Bay move only to the Tatar Strait, the Sea of Japan. None of tagged seals has been located in the “reproductive center” at the eastern coast of Sakhalin. The seals tagged in different regions of the Sea of Okhotsk have never been located in the same place during the entire annual cycle, suggesting that the sea is inhabited by two reproductively isolated groups of ringed seals.

Mantle diapirism at convergent boundaries (Sea of Japan)

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.

Distribution, resources, features of biology, and the first results of specialized fishery of shrimp <i>Pandalus goniurus</i> in the Tatar Strait

Shrimp Pandalus goniurus is poorly known in the Tatar Strait. Its distribution, state of stock, and features of biology are described on the data of 7 trawl surveys conducted by RV Buhoro in the western Tatar Strait in April-June 2009-2010 (227 trawls) and September-October 2011-2014 (589 trawls) and commercial catches obtained by fishing vessel Sovetskoye in May 2014 (50 trawls) and April 2015 (59 trawls). Horizontal opening of the scientific and commercial trawls was 16 and 35 m, respectively. About 14,000 individuals of the shrimp were subjected to biological analysis. P. goniurus was distributed along the whole continental coast of the strait northward from 47°20′ N and in spring concentrated at the depth from 50 to 120 m, rarely to 270-300 m, with single findings down to 340 m. Its stock fluctuated from 16 to 70 thousand t, on average 45,000 t (50-70 % within the territorial waters); possible annual catch was estimated as 5,000 t. Commercial fishery of this species was started in 2014 (mean CPUE 1.91 t/hour), the number of fishing vessels increased to 3 in 2015 (mean CPUE 3.26 t/hour, total landing 1160 t). The fishery is distinguished by easy hydroacoustic search of aggregations, long-time fishing within limited areas, high catches, including the catches in nighttime, and low bycatch. The highest concentration of P. goniurus was registered in April 2015: CPUE 11.86 t/hour, density 73.2 t/km 2 or 10 ind./m 2 . Size-weight parameters of P. goniurus in the Tatar Strait were the best for all its populations: their average values in commercial catches in 2014/2015 were: carapace length 20.4/22.4 mm, individual weight 5.7/7.4 g or 165/116 ind./kg. Its larvae hatching was observed in April-May, mass post-hatching molt of females was supposedly in June-July and breeding molt and spawning - in September-October. First results of the fishery are analyzed, its prospects are estimated, and measures for its regulation are proposed.

Features of the sea ice cover variability in the Tatar Strait (Japan Sea) in connection with the regional atmosphere circulation

Features of the sea ice cover variability in the Tatar Strait (Japan Sea) in connection with the regional atmosphere circulation

Distribution of organic matter, phytopigments and heterotrophic bacteria along the salinity gradient in the estuaries of small rivers of the Tatar Strait basin

Distribution of total organic matter and its dissolved and suspended forms was investigated in two small estuaries with different morphometric characteristics, as Muchke and Toki Lakes, in late July 2014 at the low tide phase. The time of survey was distinguished by low river discharge and high tides. Content of all forms of organic matter and hydrocarbons was higher in the estuarine waters, as compared with fresh river water, regardless of salinity. The dissolved form prevailed (79.7-98.6 % of the total organic matter content) with concentrations of 5.2-35.7 mg/l. Chlorophyll a dominated (up to 87 %) among phytopigments in both estuaries that corresponded to active development of microalgae. Toki Lake was distinguished by higher productivity and microplankton abundance. On the contrary, allochthonous organic matter was more abundant in Muchke Lake, where interrelation between destructors (heterotrophic bacteria number) and primary producers (Chl a concentration) was observed. Oil-oxidizing microorganisms were up to 60 % of the heterotrophic bacteria number. The hydrocarbons content exceeded the maximal permissible level: 3.6 and 4.5 MPL in Muchke and Toki Lakes, respectively. Both estuaries were subjected to chronic hydrocarbon pressure.

The first data on the biology and distribution of the Japanese fringed sculpin Porocottus japonicus Schmidt, 1935 (Scorpaeniformes: Cottidae) in the northwestern Sea of Japan

The Japanese fringed sculpin Porocottus japonicus Schmidt has been found in the Rynda (44°48′03″ N, 136°23′24″ E) and Vladimira (43°52′36″ N, 135°29′30″ E) (Sea of Japan, Primorskii krai) bays for the first time. This species was formerly known only from the northern Tatar Strait and Aniva Bay. In Primorskii krai, P. japonicus inhabits macrophyte beds in shallow sublittoral waters. It reaches a length of 112 mm during its lifespan of approximately 4 years. Spawning occurs in the winter. The species preys predominantly on polychaetes (82.3% of the food weight).

Distribution of helium and hydrogen in sediments and water on the Sakhalin slope

During the geological survey and prospecting, helium and hydrogen are recognized indicators of minerals, deep-seated faults, seismic activity, and ascending deep fluids. Their anomalous concentrations also serve as a marker of metamorphic processes. Helium survey is applied for tracing deep-seated faults and mapping permeable zones. In this work, the first results of gas geochemical survey in marine sediments and water to study the distribution of helium and hydrogen and their relation with the seismic activity of some geological structures in the southwestern Sea of Okhotsk and northern Sea of Japan. Anomalies of these gases (He up to 60 ppm, H up to 120 ppm) were identified in the hydrate-bearing sediments in the fault zones. It was also found that helium concentrations in the water column of the Tatar Strait are higher than in the studied area of the Sea of Okhotsk, possibly, due to the difference in geological structure and seismotectonic activation. Moreover, coal layers could be a significant source of methane in the gashydrate-bearing layers of the Tatar Strait.

Lead, cadmium, and arsenic in commercial algae of the Sea of Japan

The concentrations of toxic elements (arsenic, cadmium, lead) in commercial algae Saccharina japonica and Ahnfeltia tobuchiensis from different habitats of the Sea of Japan have been determined. Bioaccumulation of heavy metals has been analyzed with respect to the habitat and growth conditions. The lead content of Sascharina japonica from all habitats and arsenic content of the same alga species from the Ol’ga Bay, Kievka Bay, and Tatar Strait have been found to exceed maximum permissible levels. Increased lead concentrations have been detected in Ahnfeltia tobuchiensis. Samples of Ahnfeltia tobuchiensis collected from the bottom layer contain more toxic elements than those from the upper layer.

Peculiarities of the distribution of methane concentration and methane fluxes at the water-air interface in the Tatar Strait of the Sea of Japan

The spatial distribution ofthe methane content in the sea water in the Tatar Strait ofthe Sea of Japan is investigated using the data of expeditionary studies in 2012-2013. The developed model enabled computing methane fluxes at the water-air interface. Identified are the water areas of active methane emission in the area of underwater gas blowouts. Revealed is the abnormal concentration of methane in the areas of emission of natural gas bubbles on the western shelf and on the slope of Sakhalin Island. These bubbles give rise to the upwelling of bottom water to the overlying layers. It is discovered that the formation of the cold subsurface layer (CSL) of sea water being especially active in the area of gas blowouts is caused by phase transitions as a result of the hydrophobic hydration of natural gas molecules.

Trace elements and Sr isotopes in the crude oils from the Sakhalin offshore fields

Data on the concentrations of rare-earth elements and other metals in oils from Sakhalin fields were obtained by inductively coupled plasma mass spectrometry. The chemical preparation of the samples included the stages of acid digestion and ashing. In terms of the total metal contents; V, Ni, and Fe ratios; and Sr isotope ratios, the oil samples are divided into three groups. The crude oils from the extreme northeastern part of the island shelf, which are assigned to group I, differ from the other oils in the high contents of V and other metals, as well as the high V/Ni and V/Fe ratios. The crude oils of the group II fields located southward have elevated contents of REE and some other lithophile elements and moderate V/Ni and V/Fe ratios. Group III fields from the same area and from the Tatar Strait have low metal concentrations and low V/Ni and V/Fe ratios. The 87Sr/86Sr ratio is comparatively low in the group II oil (0.70838–0.70858) and elevated in the group III oil (0.70854–0.70911). The Sr isotope ratio of the crude oils of the Kaigan-Vasyukan deposit (group I) originated from marine organic matter (0.70867–0.70884) is correlated with 87Sr/86Sr ratios in sea-water with an age of 18.0–10.5 Ma. Based on the REE patterns, the V/Ni ratios, and the results of the multielement factor analysis, the crude oils of group III and, to a lesser extent, of group II are similar to the West Siberian crude oils.

Estimating Denitrification Rates in the East/Japan Sea Using Extended Optimum Multi-Parameter Analysis

Denitrification rates in the East/Japan Sea (EJS) were examined with extended Optimum Multi-Parameter (eOMP) analysis. The potential denitrification locations expected from the eOMP analysis occurred only in the Ulleung Basin (UB) and near the Tatar Strait (TtS) of the Eastern Japan Basin (EJB). Estimated denitrification rates were ~0.3-3 and ~4-11 μmol N m^(-2) d^(-1) in the UB and in the EJB, respectively. These rates agree with previous published results. The EJS's rates were lower than reported for other marginal seas. However, considering the rapid EJS response to climate change, we predict that denitrification may be enhanced in the near future.

The distribution, morphology, and taxonomic position of Psychrolutes pustulosus (Schmidt, 1937) (Scorpaeniformes: Psychrolutidae)

The external morphology, osteology, and distribution of a rare fish species Psychrolutes pustulosus (Scorpaeniformes: Psychrolutidae) is examined based on an extensive material for the first time. P. pustulosus shows an extreme degree of reduction of the skeleton among the Psychrolutidae. The comparative morpho� logical analysis confirms the placement of this species in the genus Psychrolutes rather than in Gilbertidia. The new data show that P. pustulosus is widespread in the Sea of Okhotsk. The occurrence of this species in the Sea of Japan (Tatar Strait, Peter the Great Bay) is recorded for the first time. Reports on the findings of P. pustulosus in the Bering Sea are erroneous.

Chlorinated pesticides in tissues and organs of spotted seals (Phoca largha Pallas, 1811) from the Sea of Japan

Concentrations of chlorinated hydrocarbons and their derivatives in the organs of spotted seals captured in the Sea of Japan are determined. Isomers of hexachlorocyclohexane (HCCH) and metabolites of dichlorodiphenyltrihlormetilmetan (DDT) are detected in all the studied animals in all the samples, but the highest concentrations are found in adipose tissue, which is a peculiar depot in which toxins are accumulated. Substantial differences in the extent of damage by toxins are discovered in seals of different populations, which is due to different intensities in the action of technogenic load on separate water areas. The level of accumulation of lipophilic xenobiotics in the tissues and organs of spotted seals of the Sea of Japan, particularly from the Peter the Great Bay (PGB), turn out to be very high (several orders of magnitude higher than that in spotted seals from the Tatar Strait and the coastal region of Hokkaido). Such a high level of chlorinated organic pesticides (COPs) has not yet been detected in any Pinnipeds inhabiting the northern part of the Pacific Ocean. The results of our studies allow us to state that COPs have been present in the ecosystem are the Sea of Japan for a long time and have undergone substantial transformation.

Infestation of walleye pollock with the parasitic copepod Haemobaphes diceraus Wilson, 1917 (Copepoda: Pennellidae) in waters of Sakhalin and the Kuril Islands

The infestation of walleye pollock with a parasitic copepod Haemobaphes diceraus at the coasts of Sakhalin and the Kuril Islands was studied during the spring of 2008. The extensiveness of the infestation in Pacific waters of the northern Kurils was 1.85–1.97%. In the southern Kurils it was from 2.0% (northeast of Iturup Island) to 7.41% (Prostor Bay), in the Tatar Strait it was 1.61%, and off northern Sakhalin Island it was 0.46%.

The Amur River runoff formation in the Amur liman

Periodical surface currents with the periods of 46.5, 61, and 91 days detected from the satellite data in the Tatar Strait and Sakhalin Bay are presented as an effect of the Amur River runoff transformation in the estuary. The estuary transforms the flow as a flip-flop directing the Amur runoff by turns to the Sea of Japan or to the Sea of Okhotsk. The flip-flop period is six months. From May 23 to November 10, the Amur River flows into the Sea of Okhotsk and from November 10 to May 25, into the Sea of Japan.