Southeast Coast Of Korea Research Articles

A novel paramyxean parasite, Marteilia tapetis sp. nov. (Cercozoa) infecting the digestive gland of Manila clam Ruditapes philippinarum from the southeast coast of Korea.

Paramyxean parasites in the genus Marteilia deteriorate digestive tissues of the host organisms, resulting in mortality of oysters, cockles, and mussels. Most reports of infection by Marteilia spp. are from Europe, while a new species of Marteilia was identified recently in Japan. Here, we report a previously unidentified species in the genus Marteilia from digestive diverticula of Manila clam Ruditapes philippinarum from the south coast of Korea. Prevalence of the parasite was low, 0.5-3.3% in the study sites. We characterized this species using light and transmission electron microscopy (TEM), and analyzed the 18S rDNA sequence. Light microscopy revealed the sporulation process from uninucleated stage to spore in the epithelial tissues of the digestive gland. TEM revealed that the parasites produced four secondary cells containing four tri-cellular spores. An electron-dense haplosporosome-like structure and striated inclusions were evident in the spore and the primary cells, respectively, while refringent granules were rarely observed in the secondary cells. Phylogenetic analyses of the 18S rDNA sequence placed this isolate in the genus Marteilia, although it is not identical to other known species in the genus. Based on morphological and molecular characters, we describe this species as Marteilia tapetis sp. nov., the second Marteilia species reported parasitizing Manila clams in Asian waters.

Terminal Vitalization Strategy through Optimal Route Selection Adopting CFPR Methodology

Container shipping route selection strategy has become an important component in attracting additional cargo volumes and increasing terminal competitiveness of small and medium ports (SMPs). Shipping route selection relies upon decisions based on real industry data and expert judgments. There is scant research that places emphasis on container shipping route selection as a vital aspect of SMPs. This paper bridges the gap by utilizing Consistent Fuzzy Preference Relations (CFPR) methodology, which handles both qualitative and quantitative factors in order to select optimal routes for SMPs. Donghae port, which is located on the east coast of South Korea, is analyzed as a case study. The results illustrate that volume commitment ranks first among the 19 established selection factors, followed by incentive system risk and head-haul ratio. This study also reveals that Donghae-Hochiminh is the optimal route for the Donghae port, while the container shipping route of Donghae-Port Kelang is ranked in the middle, and Donghae-Jakarta is considered to be the least optimal route amongst the three alternatives.

Measurements of mid-frequency bottom-interacting signals and geoacoustic inversion in Jinhae Bay, Southeast Korea.

Measurements of bottom-interacting signals over a frequency range of 4-12 kHz were made at two different sites in shallow water off the southeast coast of Korea. Although the distance between the sites was less than 20 km, the geological properties of surficial sediments were different. The surficial sediment at the site located on the north side was dominated by mud, and the measured bottom loss showed typical characteristics of sediment with a sound speed lower than the water sound speed. In addition, some interesting arrivals, which seemed to be reflected from a sub-sediment interface, were observed immediately following bottom arrivals in the frequency range of 4-8 kHz of some datasets. In contrast, sediment at the site located to the south was dominated by sandy mud, and the bottom loss showed typical characteristics of sediment with a higher sound speed. Geoacoustic parameters of surficial sediment were estimated using a simulated annealing method with an objective function comparing the measured bottom loss data with the Rayleigh reflection model. Surficial layer thickness was estimated based on arrival-time differences between bottom reflected and sub-bottom reflected signals. Inversion results are discussed in comparison with a bottom model constructed based on seismic data and core samples.

Correlation between SST and CDOM during Summer Coastal Upwelling along the Southeast Coast of Korea

Min, S.-H.; Park, M.-O.; Kim, S.-W.; Han, I-S.; Kim, W., and Park, Y-J., 2018. Using GOCI Data for Detection of Coastal Upwelling at East/Japan Sea. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 1471–1475. Coconut Creek (Florida), ISSN 0749-0208.Recently emergence of cold water from coastal upwelling has caused frequent damages to the coastal aquaculture along the southeast coast of Korea. So, the necessity of early forecasting of cold water using satellite data has emerged. Coastal upwelling generally detected by meteorological satellites of sea surface temperature (SST) data. However, this study tries to seek a possibility of use of ocean color satellite data to find the cold water, by Chromophoric dissolved organic matter (CDOM) concentration of upwelled cold water. The concentration of CDOM will change if coastal upwelling occurs. That could be observed through the ocean color sensor. 2017 summer, SST and CDOM concentrations in the in-situ and satellite data were matched up, when coastal upwelling occurred. As a result, SST and CDOM were correlated positively in coastal area, meanwhile negative correlation was found in off shore. When upwelling occurs, it is considered that high concentration of CDOM on the coast and subsurface flow to the off shore along with cold middle water, and then relatively low CDOM is supplied.

Physical Envirionment Associated with Upwelling off the Southeast Coast of Korea

Data from the two bottom moorings of ADCP (acoustic doppler current profiler), coastal weather station and CTC (conductivity temperature depth) observations for 2001 were analyzed to describe the physical processes associated with upwelling off the southeast coast of Korea. Winds were favorable for ...

우리나라 동해안의 해안단구 형성시기와 융기율

우리나라 동해안의 해안단구 형성시기와 융기율

Pollen record of the mid- to late-Holocene centennial climate change on the East coast of South Korea and its influential factors

To understand historical climate change in western Pacific coastal areas, a sediment core (SOJ-2) from the stable sedimentary environment of the Songjiho Lagoon on the east coast of South Korea was obtained for centennial-resolution palynological analysis. The ages of the SOJ-2 core is well controlled by carbon 14 dating with high-resolution accelerator mass spectrometry (AMS), and the results indicated a general warm to cold climate trend from the mid-Holocene to the present, which can be divided into two different stages: a warmer stage between 6842 and 1297 cal yr BP and a colder stage from 1297 cal yr BP to the present, with fluctuations during these stages. The climate was wetter from 6842 to 6227 cal yr BP and 4520 to 1297 cal yr BP and was drier from 6227 to 4520 cal yr BP. The climate changed to cold and dry during the period from 1297–425 cal yr BP. The impact of human activity on the climate began at approximately 1297 cal yr BP and became pronounced starting in 425 cal yr BP. The general cooling trend may represent a response to decreasing solar insolation; however, the relative dryness or wetness of the climate may have been co-determined by westerlies and the East Asian summer monsoon (EASM). The climate had a teleconnection with the North Atlantic region, resulting from changes in solar activity. Nevertheless, EI Niño–Southern Oscillation (ENSO) activity played an important role in impacting the EASM changes in western Pacific coastal areas.

Storm Waves on the East Coast of Korea: 20 Years of Wave Hindcasting

ABSTRACT Chun, H. and Ahn, K., 2017. Storm waves on the east coast of Korea: 20 years of wave hindcasting. This paper presents 20 years of wave hindcasting in the East Sea (Sea of Japan) to estimate return periods of storm waves at the east coast of South Korea for coastal risk management. The numerical results were validated against the measured data obtained at eight wave stations in the East Sea. The comparison of correlation coefficients of significant wave heights and wave periods, 0.81–0.95 and 0.70–0.88, respectively, between the numerical results and the measured data shows good agreement. Note that the numerical results agree well with the measurements despite the large computational grid size used. The storm waves on February 2008 were successfully simulated in the present study, and the computed peak periods at Gangneung Port showed good agreement with those measured, even though the coefficients of whitecapping dissipation were not modified. On the basis of 20 years of wave hindcasting results...

An Observational and Numerical Study of Storm-Induced Morphologic Changes at Sanpo Beach, Korea

ABSTRACT Son, S.; Kim, J.; Yoon, H.-D.; Jung, T.-H.; Do, K., and Shin, S., 2017. An observational and numerical study of storm-induced morphologic changes at Sanpo Beach, Korea. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 334–338. Coconut Creek (Florida), ISSN 0749-0208. This study was conducted to investigate morphological changes at Sanpo Beach due to the storm through field observation and numerical simulation. Sanpo Beach located on the southeast coast of Korea had been significantly affected by typhoon Goni while some changes in beach profile was expected due to the strong storm-induced currents. Series of field observations on the beach topography, bottom bathymetries, shorelines, sand samples, and incident waves were carried out in order to investigate the morphological changes at Sanpo Beach during the typhoon season. In particular, Real Time Kinematic-Global Positionin...

Variation and Structure of the Cold Water Around Ganjeol Point Off the Southeast Coast of Korea

Variation and Structure of the Cold Water Around Ganjeol Point Off the Southeast Coast of Korea

Seismic site conditions in Gangneung, Korea, based on Rayleigh-wave dispersion curves and topographic data

To determine the near-surface shear wave velocities (Vs) and characterize seismic site conditions in Gangneung, on the east coast of South Korea, passive and active surface waves were recorded at 136 sites. Dispersion images of the Rayleigh waves were obtained by the spatial autocorrelation method and inverted to Vs models. From these one-dimensional Vs models, the depth to the soft bedrock, average Vs at the top of the bedrock, average Vs of the overburden layer, average Vs in the top 30-m interval (Vs30), and average resonance frequency were estimated to be 16 ± 1 m, 481 ± 14 m/s, 254 ± 5 m/s, 374 ± 16 m/s, and 5.5 ± 0.3 Hz, respectively. A lower estimate for Vs30 and a relatively thick overburden layer make the downtown and agricultural areas in the region more prone to significant ground amplifications. Multiple regression analysis of Vs30 yielded a correlation coefficient of 0.79 with respect to the variables of elevation and topographic slope. Using this proxy-based empirical relationship, Vs30 values were computed at 13,583 sites covering the entire city. A microzonation map, constructed based on the Vs30 data, indicates that the ground in Gangneung is categorized mainly into B (44%), C (39%), and D (15%) National Earthquake Hazards Reduction Program site classes, with minor constituents assigned to the A and E classes.

Physical processes leading to the development of an anomalously large Cochlodinium polykrikoides bloom in the East sea/Japan sea

An anomalously large Harmful Algal Bloom (HAB) was observed in the southwest coast of the East/Japan Sea (hereafter the East Sea) during the summer of 2013. During this time period, the presence of Cochlodinium polykrikoides (C. polykrikoides) was detected by the Geostationary Ocean Color Imager (GOCI) and validated by in-situ observations. GOCI observations have been available since 2011, thus allowingto examine various stages of the physical condition of the developing C. polykrikoides bloom, thereby other multi-satellite and buoy measurements obtained between 2011 and 2013. Research results indicate that this HAB is related to four processes: the transport of C. polykrikoides from the south coast of Korea to the HAB area; a relatively high insolation; continuous coastal upwelling; and a favorable Sea Surface Temperature (SST) for C.polykrikoide growth. In examination of the main transport mechanisms, geostrophic current measurements were used to estimate the flow trajectories, showing water from the south coast to the HAB area off the southeast coast of Korea. Result shows that ninety percent of the water from the south coast reached the HAB area in 2013. Furthermore, to examine the insolation mechanism, the Photosynthetically available radiation (PAR) value was derived from the Moderate Resolution Imaging Spectoradiometer (MODIS), showing that PAR values were relatively high in the HAB area during HAB period (47Einm−1day−1). Moreover, Upwelling age (UA) was calculated in order to investigate the strength of coastal upwelling events, which were found to support relatively high UA values during the HAB period. The mean UA value during the HAB period was 1.01, higher than those in 2011 and 2012 which were 0.61 and 0.76, respectively. Finally, SST in the HAB area was also analyzed to examine which conditions were most favorable for HAB growth. Therefore, the results of this study suggest that the four mechanisms can explain the relative contributions of the anomalously HAB development observed off the southeast coast of Korea.

Migration of Coastal Erosional Hotspots due to Coastal Protection Structures

ABSTRACT Choi, K. H. and Kim, J. S. and Lee, J.C., 2016. Migration of coastal erosional hotspots due to coastal protection structures. In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Special Issue, No. 75, pp. 1062 - 1066. Coconut Creek (Florida), ISSN 0749-0208. Measures to protect coasts with artificial structures have recently become popular for beach management, notably in the east coast of South Korea. In many cases, however, some structures induced unwanted effects on adjacent beaches. Yet local governments continue to build these kinds of structures to solve erosion problems. In this study, coastline changes due to such construction were investigated by comparing historical aerial photographs, taking two beaches (Gusan-Wolsong coast and Osan-Yeongsin coast) as examples. In these two beaches, submerged artificial breakwaters and groins were constructed to reduce erosi...

Change detection of ocean wave characteristics

In this paper, a novel feature extraction approach is proposed for identifying ocean wave characteristics in real time. The algorithm was developed through the integration of the fuzzy C-means clustering algorithm, statistics formulation, short-time Fourier transforms, high frequency radar data processing and window function analysis. This method provides new insight into the detection of ocean wave characteristics and provides a more direct and convenient way to detect changes in ocean wave characteristics than the conventional method. To demonstrate the proposed algorithm, two Wellen radar systems were installed in Samcheok City, Gangwon-do on the East Coast of South Korea. A data set was selected for training the proposed algorithm while three other data sets, not used for the training processes, were used to validate the proposed model. The testing results demonstrate that the proposed algorithm is effective in extracting characteristic features from a variety of ocean waves. It is expected that the proposed system will accurately predict natural hazards and provide adequate warning time for people to evacuate from threatened coastal area. Hence this approach will directly contribute to the reduction of injuries and deaths in natural disasters by supplying near real-time data of the environment around coastal areas.

Shoreline change assessment for various types of coasts using multi-temporal Landsat imagery of the east coast of South Korea

ABSTRACTShoreline change assessment is an important task for protecting coastal properties and preserving coastal environments. This research aimed to assess the shoreline changes using the multi-temporal Landsat imagery, acquired from the east coast of South Korea during 1994 and 2014. The procedure for the shoreline change assessment consists of the following steps: (i) generating the normalized difference water index (NDWI) map from each Landsat image; (ii) extracting the shorelines from each NDWI map through the thresholding method; and (iii) assessing the shoreline changes in the various types of coasts such as the sandy, rocky and harbour coasts using the checkpoints with 1 km intervals. The statistical results showed that 94% of the shorelines in the sandy coasts and 96% of the shorelines in the rocky coasts moved landward between 1994 and 2014 due to coastal erosions, while 91% of the shorelines in the harbour coasts moved seaward during the same period due to the land reclamation works. This research contributed to the assessment of the shoreline changes and the calculation of the erosion rates in the various coasts of the study area between 1994 and 2014.

外来種ナンオウフジツボ<i>Perforatus perforatus</i>の北九州市洞海湾における1992年の発見は東アジア初記録

Perforatus perforatus was originally distributed from England to the Mediterranean and West Africa. It was first reported from the East Asia following its discovery in three ports near Ulsan Port, Korea, on 24 June 2006 and some other ports along the southeast coast of Korea. In Japan, this species was first reported on the basis of specimens collected at 2012 from buoys for the cultivation of rock-oysters, and thereafter was found to be widely distributed in northern Honshu. Here we re-identify as Perforatus perforatus a Japanese specimen that had been collected on 11 May 1992 from the Dokai Bay of Kitakyushu in northern Kyushu. We also provide photographs of its calcareous plates. This specimen represents the oldest record of P. perforatus from the East Asia and thereby provides an excellent example of the importance of the preservation of historical collections and preserved in the Kitakyushu Museum of Natural History and Human History, Kitakyushu, Fukuoka, Japan (KMNH IvR 500844).

부산시 오륙도 주변 해역의 해조 군집

Marine algal flora and community structure were seasonally investigated at Oryukdo, on the southeast coast of Korea, from March 2011 to February 2014. A Total of 66 seaweed species including 6 green, 7 brown and 53 red algae were identified and 23 species were found throughout the survey period. Seaweed biomass was maximal during summer in 2012 (2276.2 g wet weight <TEX>$m^{-2}$</TEX>) and minimal in winter in 2012 (9.1 g wet weight <TEX>$m^{-2}$</TEX>). The dominant species in term of biomass were Undaria pinnatifida, Dictyopteris prolifera, Dictyota dichotoma, Sargassum horneri, Rhodymenia intricata, Acrosorium polyneurum, and Polyneura japonica during the suvery period. The flora could be classified into six functional groups: coarsely branched form (30.3%), filamentous form (24.2%), thick leather form (19.7%), sheet form (15.2%), jointed calcareous form (7.6%), and crustose form (3.0%). The numbers of marine algal species in the Oryukdo area were markedly reduced when compared with previous studies at Dongbaekseom in 1971. These results suggest possible future changes in the algal vegetation, considering the physical and chemical pollution loadings in the coastal marine environment of this area.

Rip Currents Generation by Geomorphological Change in Gyeongpo Beach, South Korea

ABSTRACT Cho, W.C.; Kim, J.H.; Hur, D.S., and Kim, I.H., 2014. Rip currents generation by geomorphological change in Gyeongpo Beach, South Korea. Most beaches in Gangwon-do, South Korea have topographic characteristics that are mainly influenced by waves and seabed conditions. Gyeongpo Beach is one of the most famous beaches as a tourist attraction in the east coast of South Korea, and many people have visited and enjoyed sea-bathing in this area during the summer holiday season. However, rip currents are often source of danger for the swimmers because rip currents drag the swimmers away from the beach and put them to death by drowning. As Gyeongpo Beach has a straight shoreline, it is directly exposed to high waves that induce a significant change of bottom topography. Sandbars are usually formed in the processes of topographical changes from the swash zone to the surf zone and increase the possibility of rip current occurrence. Therefore, the monitoring of the topographic changes in this region is impor...

한국 남동해 간절곶 주변해역의 열염구조와 시공간적 변동 특성

Temporal and spatial variations of temperature and salinity around Ganjeol Point during January, April, August and November 2011 were studied using the data from CTD observations and temperature monitoring buoys deployed at 20 stations in the southeast coast of Korea. Temperature and salinity were nearly homogeneous through the whole depth by mixing of the seawater in spring and winter related to the sea surface cooling. Stratification induced by the river runoff and the bottom cold water was clear in summer. In autumn, sea water had vertical mixing initiated from surface layer and weak stratification at the middle and bottom layers. Low temperature and high salinity emerged throughout the year near Ganjeol Point, which inferred from turbulent mixing and upwelling by its topographical effect. Major periods of 1/4~1.4 day temperature fluctuations were recorded for the most part of the stations. According to the cross spectral density analysis, high coherence and small time lag for temperature fluctuation between layers were shown at Ganjeol Point. However, those features at the northen area of Hoeya river were opposed to Ganjeol Point. From analyses, thermohaline structure and its fluctuation around Ganjeol Point were characterized into those three parts, the south of Ganjeol Point, Ganjeol Point and the north of Ganjeol Point.

On the phylogeny of Euryteinae (Crustacea, Copepoda, Cyclopoida), with description of one new species from Korea

Euryte koreana sp. nov. is described from the shallow littoral on the East Coast of South Korea, and represents the first record of the subfamily Euryteinae Monchenko, 1974 in the Pacific Ocean north of the tropics. It belongs to a group of species that have the caudal rami length/width ratio of around four, but differs from all congeners by a number of morphological features. Detailed drawings and extensive scanning electron micrographs of many characters of ornamentation provided for this species should serve as a benchmark for distinguishing closely related species in this subfamily with conservative macro-morphology. A morphologically distinct population from anchialine caves in Mallorca, identified previously as Euryte longicaudaPhilippi, 1843, is described as another new species: Euryte jaumei sp. nov. To test the phylogenetic relationships of its members and previous hypotheses about generic placement of two species associated with scleractinian corals, several cladistic analyses are performed on all 16 currently recognized species of Euryteinae and two outgroups, Neocyclops australiensisKaranovic, 2008 and Troglocyclops janstockiRocha and Iliffe, 1994, using 25 morphological characters. All resulting trees suggest a close relationship between the two commensal species and them as a sister clade to all other Euryteinae. They are transferred into a newly erected genus Coraleuryte gen. nov., as C. bellatula (Humes, 1991) comb. nov. and C. verecunda (Humes, 1992) comb. nov., and a revised diagnoses is provided for the genus EurytePhilippi, 1843. Obtained cladograms also show that AncheuryteHerbst, 1989 is nested deeply within the Euryte clade, so the genus is synonymized and its only species is transferred, as E. notabilis (Herbst, 1989) comb. nov. A key to species of Euryteinae is also provided.