Akademik Oparin Research Articles

Expeditionary Studies of the Seas of Northeast Eurasia during Cruise 69 of the R/V Akademik Oparin

Expeditionary Studies of the Seas of Northeast Eurasia during Cruise 69 of the R/V Akademik Oparin

Study of Oceanographic Conditions in the Area of the Avachinskiy Bay, Kamchatka, in Winter during an Expedition on the R/V Akademik Oparin (Cruise 65)

Study of Oceanographic Conditions in the Area of the Avachinskiy Bay, Kamchatka, in Winter during an Expedition on the R/V Akademik Oparin (Cruise 65)

Formation of Abnormal Gas-Geochemical Fields and Dissolved Gases Transport at the Shallow Northeastern Shelf of Sakhalin Island in Warm Season: Expedition Data and Remote Sensing

Our paper deals with gas-geochemical measurements of CH4 and CO2, as well as the first measurements of dissolved H2 and He in the waters of the eastern shelf of Sakhalin Island, obtained during cruise 68 on the R/V Akademik Oparin (OP68) on 12–18 August 2023. The shallow eastern shelf has high concentrations of dissolved methane and helium in the water. The combined anomalies of methane and helium indicate the presence of an ascending deep fluid. The sources of methane in the studied area are the underlying oil- and gas-bearing rocks extending to the coast of the island. The deep faults of the region and the minor discontinuities that accompany them along the eastern coast of Sakhalin Island create a fluid-permeable geological environment both on the shallow shelf and on the coastal part of the island. East Sakhalin current and counter-current influence gases that migrate from lithospheric sources; these currents form a special hydrological regime that ensures high solubility of the gases released and their transfer under the lower boundary of the seasonal pycnocline to the east, where they are involved in the general circulation of the Sea of Okhotsk.

Manifestations of Authigenic Mineralization along the Continental Slope of the Sea of Japan and in the Tatar Strait (Cruise 61 on the R/V Akademik Oparin)

Manifestations of Authigenic Mineralization along the Continental Slope of the Sea of Japan and in the Tatar Strait (Cruise 61 on the R/V Akademik Oparin)

Screening of antibacterial and antioxidant activities of marine fungi isolated from the North Sea of Vietnam

Marine fungi are recognized as a rich source of pharmacologically active secondary metabolites, different from terrestrial fungi. This study aimed to assess the antimicrobial and antioxidant activities of 61 marine fungal strains isolated from 34 samples collected in the research journey of the Akademik Oparin vessel in the North Sea of Vietnam in 2021. Of these, 23 were from sponges, 21 from seaweeds, 15 from sediments, and only 2 from seawater. The antimicrobial screening results showed that 75.4% (n = 46) of fungal strains exhibited inhibitory activity against at least one test microorganism. The antioxidative properties results indicated the capacity for free DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2’-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) radical scavenging of crude extracts with 32.7% (n = 20) and 93.4% (n = 57), respectively. Six isolates with potent antibiotic and antioxidant activities were identified as belonging to the phylum Ascomycota and affiliated with five genera. Our findings indicated that these marine fungi could be impressive sources of multi-functional bioactive compounds and may find applications in the pharmaceutical industry.

ПРОЯВЛЕНИЯ АУТИГЕННОЙ МИНЕРАЛИЗАЦИИ ВДОЛЬ КОНТИНЕНТАЛЬНОГО СКЛОНА ЯПОНСКОГО МОРЯ И В ТАТАРСКОМ ПРОЛИВЕ (МАТЕРИАЛЫ 61 РЕЙСА НИС «АКАДЕМИК ОПАРИН»)

During the complex scientific research expedition in the Sea of Japan aboard the research vessel Akademik Oparin (Cruise 61), carbonate nodules were recovered by gravity coring, which were subsequently identified as pseudomorphs after ikaite (glendonite). The article presents the results of electron-probe and tomography studies of authigenic carbonates and gas-geochemical characteristics of host sediments occurring along the continental slope of the Sea of Japan and in the Tatar Strait.

STUDY OF METHANE CONCENTRATION VARIABILITY IN THE SURFACE LAYER OF THE SEA OF JAPAN IN THE CONTEXT OF SEISMIC EVENTS (BASED ON THE RESULTS OF EXPEDITION STUDIES IN 2017–2018)

A spatial distribution of methane dissolved in sea water is a critical but poorly understood factor in the context of seismic activity. Based on the results of the RV AKADEMIK OPARIN integrated geological-geophysical expedition (September 21 – October 31, 2017), this paper deals with the regularities of methane concentration variability in the surface layer of the Sea of Japan: the average growth and the average growth period were 70 % and 10 h, respectively, after each earthquake whereas a decrease in methane concentration in the sea water was 10–30 % 2–4 h before a seismic event. A decrease in methane concentration occurs irrespectively of the depth of an earthquake. The results obtained show good agreement with the published data and gaseous-geochemical monitoring materials, thus making it possible to associate seismic-related gaseous-geochemical regime not only with gas-saturated sediments but also with the water column of the Japan Basin (Sea of Japan).

A new species of <i>Boreotrophon </i>P. Fischer, 1884 (Gastropoda, Muricidae, Pagodulinae) from the Sea of Japan

Boreotrophon oparini sp. nov., found in the Sea of Japan, off Russian Maritime Territory, is described and illustrated. The type material was sampled at a depth of 40 m (holotype) and 110 m (paratype) during the 64th expedition of R/V Akademik Oparin. Boreotrophon oparini sp. nov . is compared with the sympatric B. candelabrum and other congeneric species.

Geological-Geophysical and Oceanographic Research in the Sea of Japan, Tatar Strait, on Cruise 61 of the R/V Akademik Oparin.

The paper presents brief results of comprehensive studies of the water area of the Tatar Strait and Sea of Japan obtained on cruise 61 of the R/V “Akademik Oparin” in November–December 2020. The bottom relief and geophysical and gas-geochemical fields were refined, and new features of the geochemistry and mineralogy of bottom sediments were revealed.

Expedition No. 63 to the Philippine and South China Seas on the research vessel “Akademik Oparin” (April-June 2021)

Expedition No. 63 to the Philippine and South China Seas on the research vessel “Akademik Oparin” (April-June 2021)

Study of the State and Variability of the Northwestern Japan Sea in the Autumn–Winter Period on Cruise 62 of the R/V Akademik Oparin

Study of the State and Variability of the Northwestern Japan Sea in the Autumn–Winter Period on Cruise 62 of the R/V Akademik Oparin

Study of the State and Variability of Marine Environment in the Japan/East Sea in Cruise 58 of the R/V Akademik Oparin

Study of the State and Variability of Marine Environment in the Japan/East Sea in Cruise 58 of the R/V Akademik Oparin

Geological Studies of the Upper Sedimentary Strata of Chaun Bay during Cruise 60 of the R/V Akademik Oparin

Geological Studies of the Upper Sedimentary Strata of Chaun Bay during Cruise 60 of the R/V Akademik Oparin

Integrated Expeditionary Research in the Sea of Japan and the Sea of Okhotsk on Cruise No. 55 of the R/V Akademik Oparin

According to the Plan of Complex Scientific Research of the World Ocean for 2017–2022, the V.I. Il’ichev Pacific Oceanological Institute, Far Eastern Branch, Russian Academy of Sciences, continues to study the northern part of the Sea of Japan and the Tatar Strait, carrying out a three-year plan of expeditionary research of this region. The expedition aboard the R/V Akademik Oparin (cruise no. 55) spanned from October 2 to 19, 2018. Geophysical and gas-geological study of the water area in the central and southern parts of the Tatar Strait was continued. On the rookery of Tyuleny Island, in the Sea of Okhotsk, information on sea lions and larghas were recorded, three individuals of northern fur seal were tagged with satellite trackers to study their migration routes. CTD observations of the upper layer (down to 600 m) were made on transects across mesoscale eddies in the northern part of the Sea of Japan. Expeditionary research was supported by the Council of the Earth’s Hydorsphere of the Ministry of Science and Higher Education of the Russian Federation.

Oceanographic Studies in the Northwest Pacific and Seas of Japan and Okhotsk on Cruise 73 of the R/V Professor Gagarinskiy and Cruise 53 of the R/V Akademik Oparin

During cruise 73 of the R/V Professor Gagarinskiy and cruise 53 of the R/V Akademik Oparin, oceanographic studies of the Sea of Japan and Sea of Okhotsk and the Northwest Pacific were carried out. New data were obtained on the seafloor structure, water structure, and slope convection features in the Sea of Japan.

Achievements in the Study of Marine Low-Molecular Weight Biologically Active Metabolites from the Vietnamese Territorial Waters as a Result of Expeditions aboard the Research Vessel 'Akademik Oparin' (2004-2017).

Until 2004, the secondary metabolites of marine organisms of the Vietnamese territorial waters had been studied very poorly. Only four new compounds were isolated from 1977 to 2003. Joint Russian-Vietnamese expeditions aboard the research vessel 'Akademik Oparin' made it possible to study in detail the chemical diversity of marine micro- and macroorganisms. As a result of five expeditions, more than 250 low-molecular weight natural compounds, including 117 new metabolites, were isolated from marine invertebrates and microfilamentous fungi. Their biological activities, such as cytotoxic, cytoprotective, and antioxidant activities, were investigated. Information about the structure and biological activity of the compounds, the source for their isolation and the geographical location of the objects is summarized in this review.

The integrated geological and geophysical expedition aboard the R/V Akademik Oparin to the Tatar Strait, Sea of Japan (cruise No. 54, 2017)

According to the Plan of Integrated Scientific Research of the World Ocean for 2017–2022, the Il’ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences (POI FEB RAS) began a comprehensive study of the northern part of the Sea of Japan and the Tatar Strait, having developed a three-year plan for expeditionary research in the area. The first expedition from the three-year expeditionary research cycle was carried out from September 21 to October 31, 2017 on the R/V “Akademik Oparin” (cruise № 54). The main goal of the expedition was to study the geological structure, conditions and mechanisms for the formation of the Tatar Strait, to study the correlation of the distribution of gas-fluid flows with a network of tectonic disturbances of different ranks in one of the seismic areas of Sakhalin Island, as well as the reaction of the Sea of Japan to climate change and increasing anthropogenic impacts.

SPECIES COMPOSITION AND DISTRIBUTION OF MOLLUSCA AND ECHINODERMATA ON CORAL REEFS IN SURVEY ON AKADEMIK OPARIN RC IN 2016–2017

A study on the species composition and distribution of Mollusca and Echinodermata on coral reefs from Quang Tri to Binh Thuan was conducted during the field survey between Vietnam and Russia on the AKADEMIK OPARIN RC vessel in 2016 and 2017 at 39 reef stations. 150 species were identified belonging to 100 genera, 50 families, 22 orders, 7 classes distributed on coral reefs. The species composition of mollusca and echinodermata was different between study areas.

Integrated Geological and Geophysical Expedition aboard the R/V Akademik Oparin to the Tatar Strait, Sea of Japan (Cruise 54, 2017)

According to the Plan of Integrated Scientific Research of the World Ocean for 2017–2022, the Il’ichev Pacific Oceanological Institute, Far Eastern Branch of the Russian Academy of Sciences (POI FEB RAS) began a comprehensive study of the northern part of the Sea of Japan and the Tatar Strait, having developed a three-year plan for expeditionary research in the area. The first expedition from the three-year expeditionary research cycle was carried out from September 21 to October 31, 2017 on the R/V “Akademik Oparin” (cruise № 54). The main goal of the expedition was to study the geological structure, conditions and mechanisms for the formation of the Tatar Strait, to study the correlation of the distribution of gas-fluid flows with a network of tectonic disturbances of different ranks in one of the seismic areas of Sakhalin Island, as well as the reaction of the Sea of Japan to climate change and increasing anthropogenic impacts.

The spatial-temporal variability and stability of Vietnamese reef communities

During expeditions in 2010 and 2013 on the R/V Akademik Oparin the individual coral reefs of Vietnam, whose species compositions and structures of benthic communities were first studied and described in the 1980s, were surveyed. The current state of the coral reefs was studied, significant changes in the abundances of certain hydrobionts were considered, and possible causes of these changes were discussed. It was determined that the general geomorphological zoning of the reefs, species composition, and the structure of the coral communities of the Con Dao, Lý Son (Cu Lao Re), and Thu islands have not changed significantly. However, negative changes have occurred in reefs of the Namsu (Gulf of Thailand) and Hon Mieu (Nha Trang Bay) islands as a result of increasing anthropogenic impacts. In reefs of the Cu Lao Cham and Tho Chau islands, which were almost completely destroyed or badly damaged by powerful typhoons in 2006 and 2009, signs of gradual recovery of the surviving coral and the formation of new coral populations were recorded.