Southwestward intrusion of korea strait bottom cold water observed in 2003 and 2004     

Chang?-Woong?ShinEmail author  Cheolsoo?Kim  Sang?-Kyung?Byun  Dongchull?Jeon  Sang?-Chull?Hwang 《Ocean Science Journal》2006,41(4):291-299

Hydrographic surveys were carried out four times in the western channel of the Korea Strait in March and August 2003 and in June and November 2004. The bottom cold water, which was lower than 10°C, appeared in the channel trough except in March 2003. It flowed southwestward along the shelf of Korean coasts in August 2003 and in November 2004. The width and the maximum speed of the intrusion current were about 20 km and approximately 25 cm s^-1, respectively, off Ulsan, Korea. The volume transport of the bottom cold water was estimated 0.019 Sv (Sv≡10⁶ m³ s^-1) in August 2003 and 0.026 Sv in November 2004.  相似文献   

Validation of Reference Genes for Quantitative Gene Expression Studies in Octopus minor     

Ilson Whang  Hyun-Sil Kang  Yucheol Kim 《Ocean Science Journal》2020,55(1):183-191

Widely distributed on tidal flats on the west and south coast of Korea, the long arm octopus Octopus minor is one of the important shellfish resources, as  相似文献   

Changes in Fish Assemblages after Dike Construction in the Saemangeum Area     

Jeong-Hui Kim  Sang-Hyeon Park  Seung-Ho Baek  Min-Ho Jang  Ju-Duk Yoon 《Ocean Science Journal》2020,55(1):129-142

In the Saemangeum area, construction of a dike began in 1991 and was completed in 2006; desalination is currently being conducted. In order to investigate  相似文献   

Assessing Cryptic Invasion State: Fine-Scale Genetic Analysis of Ciona savignyi Population in Putative Native Habitat of the Korean Coast     

Yi  Chang Ho  Kim  Won 《Ocean Science Journal》2020,55(1):99-113

The solitary ascidian, Ciona savignyi (Ascidiacea, Enterogona) is a notorious marine invader still expanding its habitat range worldwide. This species is considered native to the North West Pacific, but its indigeneity in Korean coastal waters has been questioned because of outdated taxonomic records and its inhabitation of oceanographically marginal areas. To clarify their cryptic invasion state, 247 individual C. savignyi samples were collected from 12 harbors and marinas on the Korean coast, and a 744 bp region of mitochondrial DNA (mtDNA) cytochrome c oxidase subunit I gene was sequenced and analyzed. Our analyses of population genetic structure and demographic history provided considerable pieces of evidence supporting their long-term establishment on the Korean coasts: differentiated population genetic structure, sequentially arrayed star-shape haplotype network, neutrality test results of past population expansions, and post-glacial colonization pattern of demography. Consequently, we concluded that C. savignyi populations on the Korean Coast are indigenous rather than exotic. These results could be used as reference data for further phylogeo graphic and demographic studies of problematic Ciona species, and to clarify and resolve similar cryptic invasion states of the other Korean coastal marine organisms. This study is the first to resolve the cryptic in vasion state of Korean marine organisms using genetic analysis.

  相似文献   

Tectonostratigraphic framework and depositional history of the deepwater Ulleung Basin,East Sea/Sea of Japan     

Kyoung-Jin Kim  Dong-Geun Yoo  Nyeon-Keon Kang  Bo-Yeon Yi 《Basin Research》2020,32(4):613-635

The Ulleung Basin, East Sea/Japan Sea, is a Neogene back-arc basin and occupies a tectonically crucial zone under the influence of relative motions between Eurasian, Pacific and Philippine Sea plates. However, the link between tectonics and sedimentation remains poorly understood in the back-arc Ulleung Basin, as it does in many other back-arc basins as well, because of a paucity of seismic data and controversy over the tectonic history of the basin. This paper presents an integrated tectonostratigraphic and sedimentary evolution in the deepwater Ulleung Basin using 2D multichannel seismic reflection data. The sedimentary succession within the deepwater Ulleung Basin is divided into four second-order seismic megasequences (MS1 to MS4). Detailed seismic stratigraphy interpretation of the four megasequences suggests the depositional history of the deepwater Ulleung Basin occurred in four stages, controlled by tectonic movement, volcanism, and sea-level fluctuations. In Stage 1 (late Oligocene through early Miocene), syn-rift sediment supplied to the basin was restricted to the southern base-of-slope, whereas the northern distal part of the basin was dominated by volcanic sills and lava flows derived from initial rifting-related volcanism. In Stage 2 (late early Miocene through middle Miocene), volcanic extrusion occurred through post-rift, chain volcanism in the earliest time, followed by hemipelagic and turbidite sedimentation in a quiescent open marine setting. In Stage 3 (late middle Miocene through late Miocene), compressional activity was predominant throughout the Ulleung Basin, resulting in regional uplift and sub-aerial erosion/denudation of the southern shelf of the basin, which provided enormous volumes of sediment into the basin through mass transport processes. In Stage 4 (early Pliocene through present), although the degree of tectonic stress decreased significantly, mass movement was still generated by sea-level fluctuations as well as compressional tectonic movement, resulting in stacked mass transport deposits along the southern basin margin. We propose a new depositional history model for the deepwater Ulleung Basin and provide a window into understanding how tectonic, volcanic and eustatic interactions control sedimentation in back-arc basins.  相似文献   

Climatically controlled lacustrine clinoforms: Theory and modelling results     

Jinyu Zhang  Cornel Olariu  Ronald Steel  Wonsuck Kim 《Basin Research》2020,32(2):240-250

Lacustrine basins and their deposits are good paleoclimate recorders and contain rich energy resources. Shelf-margin clinoforms do exist in deep lacustrine basins, but with striking differences from those in deep marine basins, caused by a correlation between the river-derived sediment supply and the lake level. This study uses empirical relationships to calculate the water and sediment discharge from rivers and coeval lake level during wet–dry cycles at 10 s of ky time scale. Sediment supply and lake-level changes are used for a stratigraphic forward model to understand how lacustrine clinoforms develop under different climate conditions. The results show that both wet and dry cycles can be associated with thick deep-water fan deposits, supporting the existing climate-driven lacustrine model proposed based on field data (e.g. Neogene Pannonian Basin and Eocene Uinta Basin). The wet period with high sediment supply and rising lake level creates the highly aggradational shelf, progradational slope and thick bottomset deposits. This is contrary from marine basin settings where the presence of rising shelf-margin trajectory commonly indicates limited deep-water fan deposits. This work suggests marine-based stratigraphic models cannot be directly applied to lacustrine basins.  相似文献   

Bathymetry enhancement by altimetry-derived gravity anomalies in the East Sea (Sea of Japan)   总被引：1，自引：0，他引：1  

Kwang Bae Kim  Yu-Shen Hsiao  Jeong Woo Kim  Bang Yong Lee  Yi Kyun Kwon  Chang Hwan Kim 《Marine Geophysical Researches》2010,31(4):285-298

The gravity-geologic method (GGM) was used to enhance the bathymetry of the East Sea (Sea of Japan) with satellite altimetry-derived free-air gravity anomalies and shipborne depth measurements. By comparison with the bathymetry model of Smith and Sandwell’s (SAS) approach (1994), GGM was found to have an advantage with short wavelength (≤12 km) components, while SAS better predicts longer wavelength (≥25 km) components, despite its dependency on density contrast. To mitigate this limitation, a tuning density contrast of 10.25 g/cm³ between seawater and the seafloor was primarily estimated by the downward continuation method and then validated by the check points method with GGM. Similarly, SAS is limited by the “A” value in low-pass part of the Wiener filter, which defines the effective range of the wavelength components on bathymetry. As a final result, we present an enhanced GGM bathymetry model by integrating all available data.  相似文献   

Distribution and expression of gas seeps in a gas hydrate province of the northeastern Sakhalin continental slope, Sea of Okhotsk   总被引：1，自引：0，他引：1  

Young Keun Jin  Young-Gyun Kim  Boris Baranov  Hitoshi Shoji  Anatoly Obzhirov 《Marine and Petroleum Geology》2011,28(10):1844-1855

Multidisciplinary surveys were conducted to investigate gas seepage and gas hydrate accumulation on the northeastern Sakhalin continental slope (NESS), Sea of Okhotsk, during joint Korean–Russian–Japanese expeditions conducted from 2003 to 2007 (CHAOS and SSGH projects). One hundred sixty-one gas seeps were detected in a 2000 km² area of the NESS (between 53°45′N and 54°45′N). Active gas seeps in a gas hydrate province on the NESS were evident from features in the water column, on the seafloor, and in the subsurface: well-defined hydroacoustic anomalies (gas flares), side-scan sonar structures with high backscatter intensity (seepage structures), bathymetric structures (pockmarks and mounds), gas- and gas-hydrate-related seismic features (bottom-simulating reflectors, gas chimneys, high-amplitude reflectors, and acoustic blanking), high methane concentrations in seawater, and gas hydrates in sediment near the seafloor. These expressions were generally spatially related; a gas flare would be associated with a seepage structure (mound), below which a gas chimney was present. The spatial distribution of gas seeps on the NESS is controlled by four types of geological structures: faults, the shelf break, seafloor canyons, and submarine slides. Gas chimneys that produced enhanced reflection on high-resolution seismic profiles are interpreted as active pathways for upward gas migration to the seafloor. The chimneys and gas flares are good indicators of active seepage.  相似文献   

A space-based decametric wavelength radio telescope concept     

K. Belov  A. Branch  S. Broschart  J. Castillo-Rogez  S. Chien  L. Clare  R. Dengler  J. Gao  D. Garza  A. Hegedus  S. Hernandez  S. Herzig  T. Imken  H. Kim  S. Mandutianu  A. Romero-Wolf  S. Schaffer  M. Troesch  E. J. Wyatt  J. Lazio 《Experimental Astronomy》2018,46(2):241-284

This paper reports a design study for a space-based decametric wavelength telescope. While not a new concept, this design study focused on many of the operational aspects that would be required for an actual mission. This design optimized the number of spacecraft to insure good visibility of approx. 80% of the radio galaxies– the primary science target for the mission. A 5,000 km lunar orbit was selected to guarantee minimal gravitational perturbations from Earth and lower radio interference. Optimal schemes for data downlink, spacecraft ranging, and power consumption were identified. An optimal mission duration of 1 year was chosen based on science goals, payload complexity, and other factors. Finally, preliminary simulations showing image reconstruction were conducted to confirm viability of the mission. This work is intended to show the viability and science benefits of conducting multi-spacecraft networked radio astronomy missions in the next few years.  相似文献   

Population Genetic Structure of Rock Bream (<Emphasis Type="Italic">Oplegnathus fasciatus</Emphasis> Temminck &amp; Schlegel, 1884) Revealed by mtDNA COI Sequence in Korea and China     

Hyun Suk Park  Choong-Gon Kim  Sung Kim  Yong-Joo Park  Hee-Jung Choi  Zhizhong Xiao  Jun Li  Yongshuang Xiao  Youn-Ho Lee 《Ocean Science Journal》2018,53(2):261-274

The rock bream, Oplegnathus fasciatus, is a common rocky reef game fish in East Asia and recently has become an aquaculture species. Despite its commercial importance, the population genetic structure of this fish species remains poorly understood. In this study, 163 specimens were collected from 6 localities along the coastal waters of Korea and China and their genetic variation was analyzed with mtDNA COI sequences. A total of 34 polymorphic sites were detected which determined 30 haplotypes. The genetic pattern reveals a low level of nucleotide diversity (0.04 ± 0.003) but a high level of haplotype diversity (0.83 ± 0.02). The 30 haplotypes are divided into two major genealogical clades: one that consists of only Zhoushan (ZS, East China Sea) specific haplotypes from the southern East China Sea and the other that consists of the remaining haplotypes from the northern East China Sea, Yellow Sea, Korea Strait, and East Sea/Sea of Japan. The two clades are separated by approximately 330~435 kyBP. Analyses of AMOVA and F_st show a significant population differentiation between the ZS sample and the other ones, corroborating separation of the two genealogical clades. Larval dispersal and the fresh Yangtze River plume are invoked as the main determining factors for this population genetic structure of O. fasciatus. Neutrality tests and mismatch distribution analyses indicate late Pleistocene population expansion along the coastal waters of Korea and China approximately 133–183 kyBP during which there were periodic cycles of glaciations and deglaciations. Such population information needs to be taken into account when stock enhancement and conservation measures are implemented for this fisheries species.  相似文献