Shelf Zone Research Articles

Distribution of Fe isotopes in particles and colloids in the salinity gradient along the Lena River plume, Laptev Sea

Abstract. Riverine Fe input is the primary Fe source for the ocean. This study is focused on the distribution of Fe along the Lena River freshwater plume in the Laptev Sea using samples from a 600 km long transect in front of the Lena River mouth. Separation of the particulate (>0.22 µm), colloidal (0.22 µm–1 kDa), and truly dissolved (<1 kDa) fractions of Fe was carried out. The total Fe concentrations ranged from 0.2 to 57 µM with Fe dominantly as particulate Fe. The loss of >99 % of particulate Fe and about 90 % of the colloidal Fe was observed across the shelf, while the truly dissolved phase was almost constant across the Laptev Sea. Thus, the truly dissolved Fe could be an important source of bioavailable Fe for plankton in the central Arctic Ocean, together with the colloidal Fe. Fe-isotope analysis showed that the particulate phase and the sediment below the Lena River freshwater plume had negative δ56Fe values (relative to IRMM-14). The colloidal Fe phase showed negative δ56Fe values close to the river mouth (about −0.20 ‰) and positive δ56Fe values in the outermost stations (about +0.10 ‰). We suggest that the shelf zone acts as a sink for Fe particles and colloids with negative δ56Fe values, representing chemically reactive ferrihydrites. The positive δ56Fe values of the colloidal phase within the outer Lena River freshwater plume might represent Fe oxyhydroxides, which remain in the water column, and will be the predominant δ56Fe composition in the Arctic Ocean.

Morphotectonic analysis of the Sali River basin, Bankura district, West Bengal

Morphotectonic analysis of a drainage system is widely applied in evaluating the morphological evolution of a region in response to tectonic deformation as reflected by structural and morphometric parameters. Essentially, the combination of lithological, tectonic, and climate factors lead the development and the evolution of a drainage system regardless of the general geological setting of a region. The Sali River is developed in the westernmost part of the shelf zone of the Bengal Basin and adjusts its course depending on the underlying geological structure, climatic effects, and tectonic activities. In order to identify the tectonic activity of the study area, morphotectonic and geomorphic analyses have been carried out by performing a tectonic lineaments analysis and by evaluating different geomorphic indices, like hypsometric integral (Hi), elongation ratio (Re), stream length-gradient index (SL), river profile, ratio of valley floor width to valley height (Vf), stream sinuosity, etc. The structural and morphological (e.g., incised valleys and hanging paleochannels) features were able to hypothesize the influence of active tectonics on the Quaternary evolution of the landscape. On the basis of morphotectonic analysis, an attempt has been made to trace out the plausible phases of the geomorphic evolution of the Sali basin by using remote sensing and GIS techniques. Analysis of the all morphometric and geomorphic indices revealed that the upper catchment tectonic activity plays an important role in the development of watershed hydrology, whereas the basin that is located in lower altitude (where Pleistocene to Holocene deposits crop out) are affected by depositional and neotectonic activity.

Geological Conditions of Gas Accumulation in the Coastal–Shelf Zone of the Peter the Great Bay, Sea of Japan

The results of the study of natural gas in Peter the Great Bay from 2009 to 2014 are reported. The data on the distribution of natural gas in the water and bottom sediments are obtained. High concentrations of gas in the bottom water and sediments are registered in some areas of the bay. The probable sources of methane and other natural gases are suggested.

Soft-walled monothalamids (Rhizaria: foraminifera) of the Crimean shelf (Black Sea): taxonomic composition and inter-regional patterns of species diversity and distribution

ABSTRACTWe present new data on monothalamous (single-chambered) foraminifera from the Black Sea Crimean shelf zone between Karkinitsky Gulf in the west to the area near Kerch in the east. Within this region we recognized a total of 40 morphospecies; 8 are assigned, in some cases tentatively, to known species and another 9 to known genera, again sometimes tentatively. Twelve species (all undescribed) are reported here for the first time. The most abundant species are Psammophaga sp. (sensu Gooday et al. 2011), Goodayia rostellata Sergeeva & Anikeeva 2008 and Vellaria pellucida Gooday & Fernando 1992, each of which is evenly distributed in all studied areas. The highest species richness of monothalamous foraminifera was observed in the Yalta region. Based on a multivariate analysis of monothalamid assemblage structure and diversity indices [Shannon (H’), Margalef (D’), eveness Pielou (J’), Simpson (1-λ’) and rarefaction ES(n)], we recognized three groups of stations, corresponding to the Western, Southern and Eastern coasts of the Crimean peninsula. The monothalamid assemblages found in each of these coastal regions exhibit different structural features and are distinguished by certain characteristic species.

Interaction of elastic waves with ice layer in shelf zone

A theoretical model for the propagation of elastic waves of arbitrary wave sizes from 0.5 to 20 units in an ice layer has been developed. The calculation was based on Green’s function theory for Helmholtz equation. Special “directed” Green’s functions were introduced. They make it possible to anayze wave fields in closes volumes limited by different-angle impedances. The developed calculation algorithms allow one to anayze fields on medium-powered computers for 15 minutes. The suggested methods are capable of estimating elastic wave interactions with different impedances in bays, lakes and other volumes with limited wave sizes.

Clostridia in Commercial Fish of the Azov and Black Seas and in Aquaculture Facilities in the Southern Region of Russia

The paper presents studies on the infection with clostridia of fish with skin lesions and ulcers on the surface of the body. The objects of study were syrman goby from the eastern part of the Taganrog Bay of the Sea of Azov, turbot from the shelf zone of the north-eastern Black Sea and carps reared under aquaculture conditions. Using an Autoflex speed III Bruker Daltonics (Germany) mass spectrometer, by the MALDI-TOF mass spectrometry was showed that sulfite-reducing clostridia (Clostridium perfringens, C. sporogenes) have been shown to infect the organs and tissues of syrman goby with vibriosis and turbot with ulcerative skin lesions of unknown etiology. Species such as Clostridium difficile, Clostridium novyi are of clinical importance and were found in the parenchymal organs of carp suffering from chronic aeromonas infection on pond fish farms in the southern Russia. These bacteria are its cosmopolitan distribution ability them to generate heat-resistant spores and cause food poisoning, which makes control and prevention measures needed in the food chain.

Карбонатные постройки шельфовых зон как критерий прогнозирования залежей и поисков углеводородного сырья

Карбонатные постройки шельфовых зон как критерий прогнозирования залежей и поисков углеводородного сырья

ГАЗОГИДРАТЫ АЗЕРБАЙДЖАНСКОГО СЕКТОРА ЮЖНОГО КАСПИЯ: ТЕРМОДИНАМИКА, СЕЙСМОАКУСТИКА И ГАЗОПРОЯВЛЕНИЯ

Актуальность. Геологическое строение и батиметрия морского дна глубоководной части Каспийского моря указывают на возможность образования значительных объемов газогидратов. Анализ опубликованных и неопубликованных материалов по газогидратам Каспийского моря показал, что в основном все работы базируются лишь на изучении скопления газогидратов Элм, Боздаг, площади Абшерон, а также термодинамических факторах региона (без учета реальных значений температуры и давления) с целью определения возможной зоны их скопления. Цель исследования заключается в подсчете объема углеводородных газов газогидратов по термодинамическим данным, а также в изучении и прогнозировании их поступления в верхнюю часть разреза. Объектом исследования являются отложения верхней части разреза. Несмотря на большой фактический материал, имеющийся в различных организациях, верхняя часть разреза в связи с оценкой газоносности является наименее изученной и описанной в литературе зоной. Это связано с тем, что основной интервал исследований в Южном Каспии сосредоточен в участках с высоким потенциалом нефти и газа. Этим интервалом является продуктивная толща и подстилающие отложения, вошедшие в зону интенсивной генерации нефти и газа. Более молодые отложения, накопившиеся до абшеронского региояруса, в подавляющем случае состоящие из глинистых осадков, не представляли интереса. Во многих работах эта зона описывается как нерасчлененная толща четвертичных отложений. Методы исследования основаны на моделировании термодинамического равновесия углеводородных газов с целью установления зоны формирования газогидратов. В работе использованы данные температур и давления, замеренные в скважинах Южного Каспия, а также данные 160 сейсмоакустических профилей, разрезы интервальных скоростей и данные по нефтегазопроявлениям в пределах шельфовой зоны Южного Каспия. В результате исследования термодинамического равновесия рассчитаны объемы зон газогидратов. Исходя из расчетов установлено, что суммарные объемы газа для изучаемой площади отложений составляют 1,151013 м3газа. В результате интерпретации сейсмоакустических данных установлено, что интенсивность проявлений газа изменяется как по площади, так и с глубиной. В зонах, прилегающих к глубоководной части Южного Каспия, присутствие аномалий, характерных для газовых зон, увеличивается по сравнению с прибортовыми зонами. В результате анализа данных по газопроявлениям можно прийти к выводу, что верхняя часть разреза Южного Каспия сильно обогащена газом, причем интенсивность газопроявлений в нижней части наиболее высокая. Нефтепроявления на структурах Хали, Чилов адасы, Палчыг Пильпиля, Чираг указывают на то, что эти структуры более благоприятны для поисков нефтяных залежей. Пластовая вода зафиксирована в широком интервале глубин. Полученные выводы дают основание прогнозировать поступление значительных объемов флюидов в верхнюю часть разреза глубоководной части Южного Каспия.

EGE DENİZİ’NDEKİ KARASULARI SORUNUNUN TÜRK VE ULUSLARARASI DENİZ TİCARETİ’NE ETKİLERİ

In today's world, one of the most fundamental strategies of states is to develop their competitive power by controlling energy lines and energy resources. Turkey, has high competitive advantage when compared to other countries especially in terms of geographic location. For this reason, Turkey has an attractive position in terms of the sharing of freight transport and having key role with maritime trade policies. Although maritime trade routes are legally free, such as transit and innocent passage, they are affected by the problem of sovereignty of sea areas. In particular, commercial routes to be followed by ships in controversial maritime areas have the potential to be influenced by a number of measures in favor of the coastal state in relation to the transition regime. Although in theory the freedom of transition is accepted, the conflicts between the coastal states in practice constitute an indicator of the big problems that can be experienced in the future. There are many world-wide problems in the coastal states such as territorial waters, continental shelf and exclusive economic zone. One of the most well-known problem is the ongoing territorial waters matter in the Aegean Sea between Greece and Turkey. In this study, the possible effects of the developments related to the limitation of territorial waters in the Aegean Sea to the maritime trade of our country and international maritime trade were evaluated. Within the scope of the research, in-depth literature was searched, the current situation was examined through maps related to maritime trade routes, and the possible scenarios were discussed and the study was terminated by presenting future measures and predictions.

Uncharted biodiversity in the marine benthos: the void of the smallish with description of ten new Platyhelminth taxa from the well-studied North Sea

Most of our planet’s biodiversity is still unknown, particularly in the sea. Although around the island of Sylt in the North Sea, the small zoobenthos (meiofauna) has been studied intensively since the 1950s, repeating previous surveys revealed an unexpected wealth of new species in addition to the 330 species of free-living microturbellarians (non-parasitic Platyhelminthes) already known from this area. Extrapolation from well-known to less-known habitat types suggests that a total of some 520 Platyhelminth species should be expected around this island, about 670 in the North Sea ecoregion, and 830 in the ‘Northern European Sea’ ecoprovince. Assuming that the other biogeographic provinces of the planet harbour a similar diversity, a total of some 20,000 marine microturbellarian species is estimated for the global shelf zones. Less than 10% of these are known by now. As a contribution to fill that gap, ten new taxa are described: Coelogynopora minuta n. sp., Coelogynopora sopottehlersae n. sp., Cirrifera paraculeata n. sp., Boreocelis fragilis n. sp., Postbursoplana noldti n. sp., Promesostoma wehrenbergi n. sp., Ptyalorhynchus oculatus n. sp., Acrorhynchides canaliculatus n. sp., Dactyloplana n. gen., and Dactyloplana tridigitata n. sp.

Trophic Characteristics of Mnemiopsis leidyi and Its Impact on the Plankton Community in Black Sea Coastal Waters

The quantitative development of Mnemiopsis leidyi, the species structure of mesoplankton, and the food spectrum of ctenophores were studied in the shelf zone off the Crimean coast of the Black Sea during the summer seasons of 2013 and 2014. The feeding rate of the M. leidyi population and its predation pressure on the entire zooplankton community and certain species populations have been estimated from data on the diet composition, digestion time, and abundance of ctenophores. The volume of water cleared by M. leidyi varies by more than an order of magnitude depending on the systematic affiliation of the organisms consumed: it is maximum in the case of preying on Cladocera and Bivalvia veligers (up to 12 L ind.–1 h–1) and significantly lower for Copepoda (0.4–2.0 L ind.–1 h–1). The relationship between the value of the specific daily ration and carbon content in a M. leidyi body in the summer months of 2013 and 2014 is described by a parabolic equation with an exponent of –0.346 to –0.852. In 2014, the highest predation pressure, compared to other groups, was exerted on Copepoda and veligers of Bivalvia (on average 2.9 ± 1.5 and 2.2 ± 0.7% of biomass per day). The mean daily rate of predation on zooplankton in the Black Sea coastal zone was lower in 2014 (1.54 ± 0.58%) than in 2013 (3.94 ± 1.2% of zooplankton biomass) due to the low abundance of ctenophores. A comparative analysis of long-term data on the trophic role of the ctenophore in the plankton community has shown that the food spectrum, as well as the rate of predation on certain groups, varies from year to year. The low rate of predation on forage zooplankton by the M. leidyi population in recent years (2–5% of biomass per day) does not influence the interannual zooplankton dynamics in Black Sea coastal waters.

Virioplankton of the Kara Sea and the Yenisei River estuary in early spring

Here we present our research results on the virioplankton of the shelf zone of the Kara Sea. This is the first study of viruses and bacteria done in the Kara Sea in early spring when viruses can play an important role in the abundance and production control of the bacterioplankton. All other studies cover July–September, that is, when the Kara Sea is completely ice-free and the community of viruses and bacteria is in an absolutely different stage of development. The samples were collected and processed on board of the vessel “Norilskiy Nickel” (project Aker ACS 650) between March 29 and April 8, 2016 on the regular cruise Murmansk – Dudinka. The abundance of bacteria (NB) and viruses (NV) located both underneath the ice and in the open waters of the Kara Sea and the Yenisei River estuary varied within a range of (0.075–0.429) × 106 cells × ml−1 and (0.30–2.11) × 106 viral particles × ml−1, respectively, and the NV/NB ratio varied from 2.6 to 15.4. A positive correlation was found between NB and NV (R = 0.70, p = 0.05). Viruses with capsid diameter of 16–297 nm were registered in the water samples examined. The transmission electron microscopy data show that the fraction of the virus-infected bacterial cells is about 0.2–2.3% of total NB. The mean viral-induced mortality of the bacteria calculated from all the sampling stations in the Kara Sea and the Yenisei River estuary was 7.8 ± 1.2% (with a range from 1.4 to 20.2%) of the daily bacterioplankton production. Our results show that viruses play an important role in the abundance and production of bacterioplankton control in early spring.

DEVELOPMENT OF LOCAL COMMUNITIES ON THE BASIS OF EXPERIMENTAL BOTTOM STATIONS IN DIFFERENT ZONES OF THE NORTH-CASPIAN SHELF

Aim.On the basis of four experimental bottom stations installed at various depths of the North Caspian shelf, the local communities of marine organisms were formed, on various constructions and in close proximity to them were investigated. The aim of the work is to study the features of community development on the basis of bottom biological stations, to measure their quantitative characteristics, to assess the informative character of the structural and functional characteristics of local communities for analyzing the state of the marine environment. Methods. Experimental bottom stations were installed in various regions of the North Caspian shelf using diving equipment to study their impact on the environment. Control over the development of associated fauna was carried out with the help of traps and the method of direct accounting for the materials of photo-video surveys. Sampling of fouling was carried out by the method of registration sites. Based on the number of species of flora and fauna of local communities, a ballroom information system has been suggested, that can be used for monitoring. Results. Research materials indicate a significant difference in the species composition, biomass and the structure of communities of local cenoses formed at the bottom stations with the same design and ecological capacity at various depths of the North Caspian shelf. In the shallow shelf zone at depths of 6-8 m in the local community of the bottom station, the vegetation component is dominant. At great depths, the total biomass increases in local cenoses and animal communities, including filter-feeders, make significant contribution to the self-purification of the marine environment. Conclusions. The results indicate the possibility of using complex observations of the structure and functional characteristics of local communities formed on the base of bottom stations, as well as the development of species of indicators and objects of accumulation of toxicants for assessing the state of the marine environment. The development of this approach involves the experiments with different station costructioons and materials and use of biotechnology implantation of test organisms on the design of bottom stations.

Strong Variability of Sound Velocity in the Black Sea Shelf Zone Caused by Inertial Internal Waves

The paper presents research results on sound velocity variability in the water column based on long-term measurements conducted on stationary platforms on the Crimean and southeastern shelves of the Black Sea in the summer–fall seasons. Measurements consisted of long-term hourly soundings with a miniSVP sound velocity probe, continuous temperature recording with a thermistor chain, and current monitoring with ADCPs. A significant and frequently observed variability in the sound velocity fields was revealed during the passage of inertial internal waves and internal bores, both on the Crimean and Caucasian shelves.

The Geological History of the Kerch–Taman Area Based on a Reconstructed Regional Balanced Section

The geological framework and tectonics of the East Black Sea region is characterized through balancing a geological cross-section and paleoreconstruction during the Paleogene–Neogene period. The studied area includes the Kerch–Taman trough, the Anapa Swell (a continuation of the immersed part of the Greater Caucasus Orogen), the Tuapse trough, and the Shatsky Swell. This paper is mainly focused on the Russian shelf zone of the Black Sea. The results are important for understanding the trap formation time and the preservation of hydrocarbon deposits in the Russian sector of the Black Sea shelf.

Geological history of the Kerch-Taman area based on the reconstruction of the regional balanced section

The geological framework and tectonics of the Eastern Black Sea region is characterized through balancing a geological cross-section and paleoreconstruction during the Paleogene-Neogene period. Studied area includes the Kerch-Taman Trough, the Anapa Swell (the continuation of the immersed part of the Greater Caucasus Orogen), the Tuapse trough and the Shatsky Swell. The paper is mainly focused on the Russian shelf zone of the Black sea. The results are important for understanding of the trap formation time and the hydrocarbon deposits preservation in the Russian sector of the Black sea shelf.

Atmospheric Internal Gravity Waves Caused by Tsunamis over Kuril Islands

MODIS (Aqua and Terra) space images of the northwest part of the Pacific Ocean at instants of considerable tsunamis in 2009–2011 have been analyzed. Periodic cloud structures typical for internal gravity waves (IGWs) in the atmosphere have been revealed in the region of the Kuril Islands in five cases. It has been shown that the meteorological conditions observed during those events favored the appearance of such phenomena. The continuous oceanic upwelling in the region of the Kuril–Kamchatka Trench is a favorable factor for IGW generation due to the creation of temperature contrasts observed both in warm and cold seasons between the ground layer of the atmosphere and ocean surface. The estimate of the structure of cloud manifestations of atmospheric waves by satellite images testifies also to the influence of the Kuril Ridge orography on their appearance and propagation over the water area under study. The increase in amplitudes and duration of oscillations caused by the tsunami in the shelf zone can be an auxiliary factor for the IGW generation over coastal territories.

Distribution and Some Features of Biology of Gilbert’s Irish Lord Hemilepidotus gilberti (Cottidae) in the Russian Waters of the Sea of Japan

Main concentrations of Gilbert’s Irish lord Hemilepidotus gilberti in the Russian waters of the Sea of Japan are registered off the coasts of South and Central Primorye and western Sakhalin. During the course of the year, the representatives of the species are found at the depths between 9 and 668 m at a water temperature of the near-bottom layer from –1.8 to +16.1°С. In the summer, they prefer the upper and middle zones of the shelf with a temperature between 1.5 and 3.0°С, while the fishes are found in the lower part of the shelf and upper zone of the continental slope with low positive temperatures in the winter. The juveniles live at smaller depths than adult individuals and at the largest seasonal temperature fluctuations. The fishes 3–37 cm in body length are registered in the catches, and the size group 18–26 cm prevails. The females are more abundant in the population, and they reach a larger body size than the males. Mass spawning occurs in August and September at the depth of 30–80 m. In the waters of Primorye, Gilbert’s Irish lord feeds on mainly decapods, polychaetes, and amphipods. From April to November, the daily ration of the juveniles and adult fishes is equal to 5.0 and 3.0% of body weight, respectively. Two maximums are observed in the feeding intensity of adult fishes: prespawning (July) and postspawning (November). The biomass of Gilbert’s Irish lord in the Russian waters of the Sea of Japan is estimated as 1500 t.

Development of a mobile robot group for coastal monitoring

In Russian Federation rich oil and half of all gas reserves are distributed along the sea shelves. Severe weather conditions, frequent storms and intense sea waves, complicate exploring and mining of new shelf deposits. Therefore nowadays stationary automated systems are used for monitoring the environment in the shelf zone of the Sea of Okhotsk near Sakhalin Island. But they provide data only for specific areas of operation. Such restrictions can be removed by using groups of remotely controlled mobile robots. Moreover, mobile vehicles should be able to operate under any weather conditions. This paper summarizes the research results of the development and creation of efficient chassis designs for coastal areas of Sakhalin Island and adjacent waters. The technique for choosing vehicle design parameters and assessing the efficiency of the system as a whole is given. Data on physical and mechanical characteristics of soil and gravel bases in the coastal zone were used for estimating vehicles’ cross-country ability. To create a multi-agent coastal monitoring system we intend to use several ground, underwater and overwater robots able to exchange information in real time. We give an outline of a mobile robot group operation, the group being composed of ground, underwater and overwater robots. The use of mobile robots for performing the tasks mentioned above has the following advantages: expansion of the working area achieved by allocating the robots; highly probable accomplishment of the task due to the possibility of redistribution of targets among group members; the ability to take measurements at several locations simultaneously.

HYDRO-GEOBIOGENIC-MANTLE PARADIGM OF HYDROCARBON ORIGIN – BASIS OF DIRECT STUDY TECHNOLOGY OF STRUCTURAL-THERMO-ATMO-HYDROLOGICAL-GEOCHEMICAL RESEARCHES

In a set of two mutually complementary ideas and the unity of biogenic-mantle processes it is proposed to consider the hydro-geosynergic biogenic mantle theory as a unified forming paradigm of the origin of hydrocarbons. On this basis, it is proposed to adopt a new direct-search structural-thermo-atmo-hydrological-geochemical technology, which takes into account practically the entire genetic complex of the global cycle and allows reasonable use the unifying genetic bases of the operating paradigms that complement each other. The main mechanism of the hydrocarbon genesis is the global circulation of matter in nature − water, biota and geological processes (geodynamics, geochemistry, geothermics), which corresponds to predictive-search technology in oil and gas bearing areas of land, coastal slopes, shelf zones, coal-rock pools.