West Coast Of Korea Research Articles

Community Structure and Health Assessment of Macrobenthos in Tidal Flats along the West Coast of Korea in Spring and Summer

Community Structure and Health Assessment of Macrobenthos in Tidal Flats along the West Coast of Korea in Spring and Summer

Negative Impacts of Perkinsus olseni Infection in Manila Clam Ruditapes philippinarum Observed from Tidal Flats in Anmyeondo Island on the West Coast of Korea During Post-Spawning Period

Negative Impacts of Perkinsus olseni Infection in Manila Clam Ruditapes philippinarum Observed from Tidal Flats in Anmyeondo Island on the West Coast of Korea During Post-Spawning Period

Spatial distribution and source identification of traditional and emerging persistent toxic substances in the offshore sediment of South Korea

While the coastal pollution of persistent toxic substances (PTSs) has been widely documented, information on offshore environments remains limited. Here, we investigated the spatial distribution and sources of PTSs in the offshore sediments (n = 34) of South Korea. Sediment samples collected from the Yellow Sea (n = 18), the South Sea (n = 10), and the East Sea (n = 6), in 2017–18 were analyzed for a total of 71 PTSs. Target compounds include 31 PCBs, 15 PAHs, 9 emerging PAHs (e-PAHs), 10 styrene oligomers (SOs), and 6 alkylphenols (APs). Sedimentary PCBs showed relatively low concentrations with no significant difference across the three seas (0.16–6.9 ng g−1 normalized organic carbon, OC). Low-chlorinated PCBs (tri- and tetra Cl-CBs) were predominant (mean: 77%), primarily indicating atmospheric inputs. PAHs widely accumulated in the three seas with low to moderate level (22–250 ng g−1 OC), and dominated by high molecular weight PAHs (4–6 rings). PMF analysis revealed coast-specific PAHs sources; i.e., originated from mainly coke production (77%) in the Yellow Sea, vehicle emissions (68%) in the South Sea, and fossil fuel combustion (49%) in the East Sea. SOs showed significant contamination than other PTSs, with elevated concentrations in the Yellow Sea (mean: 350 ng g−1 OC). APs showed a similar regional distribution to SOs, but concentrations were much lower (mean: 17 ng g−1 OC). SOs and APs seemed to be introduced from rivers and estuaries on the west coast of Korea, where industrial and municipal activities are concentrated, then might be transported to offshore through tide or currents. Overall, the novel data presented for various PTSs in offshore Korean sediments warrant the necessity of a long-term monitoring effort and urgent management practice to protect marine ecosystem.

Field Observation and Numerical Modelling for Morphological Response in the Macro-tidal Beach

This study investigated the sediment transport and bed level change in the macro-tidal beach using field observation and numerical modelling. The study area is Sinduri beach, located on the west coast of Korea, which developed a large scale multi-sand bar with a tidal range of 5 to 7 m. The multi-sand bar is destroyed in the high-wave conditions (winter) and developed in the low-wave conditions (summer), which have different characteristics from the wave-dominated beach. Therefore, this study measured the wave level, current, and bed level change using ADCP (Acoustic Doppler Current Profilers) and VRS-GSP (Virtual Reference Station Global Positioning Systems) to investigate the mechanism of the multi-sand bar formation. Then, this study simulated sediment transport and bed level change, coupled with the Delft3D-FLOW and Delft3D-WAVE model. The numerical results show that sediment transport and bed level change dominantly occurred under the shore-normal wave condition and tend to develop a multi-sand bar. However, the destruction of the multi-sand bar was not reproduced. Delft3D-FLOW model is based on the two-dimensional depth-averaged shallow water equation and it is not applicable to simulate the wave-induced current near the seabed. Also, the aeolian sediment transport by north-west wind can not involve in the numerical simulation. Keywords: wave, tide, macro-tidal beach, Delft3D, sediment transport

Temporal variation of sulfate concentration in PM2.5 and major factors enhancing sulfate concentration in the atmosphere of Seoul, Korea

Despite frequent observations of high particulate matter (PM) concentrations in Seoul, Korea, the sulfate (SO42−) concentrations in PM with an aerodynamic diameter below or equal to 2.5 μm (PM2.5) in Seoul have been reduced during the 1990s. However, there has been no decreasing trend during the 2000s. Despite the very low ambient SO2 concentrations, high SO42− concentration episodes frequently occur in Seoul; however, the reasons for this remain poorly understood. In the present study, we sought to determine the major factors that enhance sulfur oxidation in Seoul by analyzing measurement data from an intensive air quality monitoring station in the Seoul metropolitan area acquired in 2015. Additionally, we aimed to distinguish the contributions of local sources and long-range transport to the elevated SO42− concentrations in PM2.5 in Seoul. In some cases in March and October 2015, the molar ratio of SO42− to SO2, which reflects sulfur partitioning between the particle and gas phases, showed an exponential increase with an increase of relative humidity (RH). However, despite the fact that the RH was high during August 2015, no statistically significant relationship was observed between RH and the molar ratio of SO42− to SO2 during this month. In August 2015, the molar ratio of SO42− to SO2 showed an exponential increase with increasing O3 concentration. Therefore, under sufficient RH, the concentrations of radical oxidants might be the most important factor that underlies the increase in ambient SO42− concentrations. No significant relationship was observed between the molar ratio of SO42− to SO2 and O3 in October. Furthermore, using Potential Source Density Function (PSDF) and backward trajectory analysis, the high SO42− concentrations in March 2015 were found to be caused by the transportation of air pollutants from China and local sources around Seoul. The high SO42− concentrations in August 2015 are concluded to have been greatly affected by these power plant emissions in the Taean area on the west coast of Korea. The high SO42− concentrations in October 2015 appear to have been caused by the transportation of air pollutants from North Korea. In summary, the high SO42− concentration in Seoul is affected by long-range transport from China and by the emissions from around the Seoul metropolitan area, such as Taean or North Korea.

서해안 대기 중 비래염분 및 콘크리트 내 염화물 침투량 상관성 분석

본 연구에서는 콘크리트 내부 침투염화물량에 미치는 비래염분의 영향을 배합 및 해안거리에 따라 분석하기 위하여 서해안 고창지역에서 옥외노출시험을 5년간 실시하였다. 다양한 물-시멘트비를 가지는 콘크리트 시험체를 제작하여 10~5,000 m 해안거리에 위치시킨 다음, 대기 중 비래염분량, 시험체 표면 및 깊이별 염분량을 측정하여 비래염분과 표면염화물량, 침투염화 물량간의 상관성을 분석하였다. 비래염분량과 표면염화물량은 거듭제곱모형을, 표면염화물량과 침투염화물량은 선형모형을 사용하여 상관성 분석을 수행하였으며, 이로부터 비래염분 환경조건을 통해 표면염화물량 및 침투염화물량을 예측함으로써 선제적으로 염해에 대응할 수 있다는 가능성을 확인하였다.

Weather-Driven Coastal Dynamics in a Tide-Dominated Area: Cases from Spring 2016 along the West Coast of Korea

Kim, B.-J.; Lee, D.E.; Ro, Y.-J., and Jeong, K.-Y., 2021. Weather-driven coastal dynamics in a tide-dominated area: Cases from Spring 2016 along the west coast of Korea. Journal of Coastal Research, 37(3), 494–505. Coconut Creek (Florida), ISSN 0749-0208.Analyses of current dynamics recorded using multilayer current meters in Spring 2016 (15 April–17 May, 32 d) at two stations near Kkotji Beach in Anmyeon-do, Yellow Sea, Korea, are presented. Harmonic analysis is applied to identify tidal characteristics in the study area. A slightly rotational current pattern is detected at ST01, while oscillations predominantly in north–south orientation are detected at ST02. Nontidal residual currents and the concurrent surface atmosphere data are analyzed together. Residual currents converge (diverge) between ST01 and ST02 following the increase (decrease) in thickness between two stations. Using advanced statistical methods, the spatial patterns of such dynamic events are shown with their association with surface atmosphere. Complex correlation analysis reveals that residual currents are significantly correlated with abrupt surface wind fluctuations associated with extratropical cyclones. The characteristics of residual currents and surface wind vectors are further analyzed, using complex empirical orthogonal functions (CEOF). The first residual current mode (R1) accounts for 46.8% of the total variation, while the second mode (R2) accounts for 24.9%. R1 represents a wind-induced component in the longshore direction, while R2 represents a bottom-driven component in the opposite direction. Both the modes correlate significantly with the first wind mode (W1, longshore wind), which leads the associated residual current modes by a few hours. Spectral analysis indicates that the two significant periods of surface wind and residual current modes are well matched to each other, exhibiting cycles of 1.6 and 4 days.

Middle Holocene Coastal Environmental and Climate Change on the Southern Coast of Korea

We obtained a 15 m drill core from Deukryang Bay on the southwest coast of Korea, which is now an area of reclaimed land used for agriculture. We investigated changes in the depositional environment and hydrological climate responses to sea level changes using sedimentary facies, radiocarbon ages, grain-size analysis, total organic carbon (TOC), total sulfur (TS), and stable carbon isotopes (δ13C). Sediment deposition began at 12,000 cal yr BP and was divided into four stages based on changes from fluvial to intertidal environments related to Holocene marine transgression events. Stage 1 (>10,000 cal yr BP) is represented by fluvial sediments; Stage 2 (10,000–7080 cal yr BP) is represented by the deposition of mud facies in an intertidal zone in response to sea level rise; Stage 3 (7080–3300 cal yr BP) was a period of gradually descending sea level following the Holocene maximum sea level and is characterized by gradual changes in TOC, TS, and C/S ratios compared with the mud facies of Stage 2. Stage 4 (3300 to present) was deposited in a supratidal zone and contains low TS and an abundance of TOC. Based on our TS and C/S ratio results, the south coast of Korea was mainly affected by sea level rise between 7000 and 3000 cal yr BP, during the middle Holocene. At 3000 cal yr BP, sea level began to stabilize or gradually decrease. In addition, changes in δ13C values are clearly observed since ca. 5000 cal yr BP, in particular, large hydrological changes via freshwater input are confirmed in 4000–3000 cal yr BP. We consider these shifts in freshwater input indicators of an increased influence of El Niño and La Niña conditions, related to the weakening of the East Asian Summer Monsoon (EASM) and changes in sea surface temperature (SST) of the Western Pacific Ocean during the middle Holocene climatic optimum (between 7800 and 5000 cal yr BP). The cooling periods of SST in East Asia between 8400 and 6600 cal yr BP reported from the west coast of Korea are related closely to changes in vegetation (as evidenced by δ13C) from 7700 cal yrs BP to the present in the southwest coast of Korea. We interpret the freshwater input events at 4000–3000 cal yr BP to be related to changes in SST in response to the weakening of the EASM on the southwest coast of Korea. However, additional research is needed to study the southward migration effect of the westerly jet related to SST and atmospheric circulation controlling terrestrial climate in the middle Holocene.

The Effect of Laver-Farming on the Distribution of Copepod Community in the West Coast of Korea

Kim, S,-K.; Kim, J.-C., and Choi, J.-Y., 2020. The effect of laver-farming on the distribution of copepod community in the west coast of Korea. In: Jung, H.-S.; Lee, S.; Ryu, J.-H., and Cui, T. (eds.), Advances in Geospatial Research of Coastal Environments. Journal of Coastal Research, Special Issue No. 102, pp. 63-68. Coconut Creek (Florida), ISSN 0749-0208.To understand the effect of farms on copepod communities in the coastal marine environment, this study investigated the environmental variables and copepod communities in June 2016 in the coastal region adjacent to the Geum River estuary. Copepod communities were more abundant in laver farms than in areas not covered by laver farms, due to the availability of various food sources and low predation risks. Although laver farms had low abundance (cells/mL) of phytoplankton, they were observed to have high species diversity. This provides an environment in which a variety of food items is available for copepod communities. Moreover, fishes were more abundant in the areas not occupied by farms than in laver farms. the complex habitat structure created by abundant laver, as well as frequent human interference in laver farms, has a negative impact on the distribution of fish communities. However, the abundance of copepod communities in laver farms is important for a continuous supplement to the diet of fishes in the marine environment, where food sources are likely to be depleted. Thus, the positive effects of laver farms on copepod communities can greatly contribute to the population growth of fishes and to the sustainability of copepod communities in the coastal marine environment. However, the artificial disturbances that frequently occur in laver farms are likely to lead to eutrophication and various types of water pollution in the coastal marine environment, so proper control and management of human activity are required.

Are Juvenile Manila Clam Ruditapes philippinarum Free from Perkinsus olseni Infection in Korean Waters?

As a suspension feeder, Manila clam Ruditapes philippinarum (A. Adams and Reeve 1850) plays a crucial role in the coastal soft bottom ecosystem in the temperate region, linking the benthic primary production to the upper trophic level. Manila clam density on tidal flats on the west coast of Korea has been declining for the past decades, and infection by the protozoan parasite Perkinsus olseni (Lester and Davis 1981) is one of the major causes for the decline. Recent studies carried out in Japan revealed that P. olseni induces mortalities of the juveniles in their natural habitats, which may lead to the recruitment failure and subsequent decline in the clam population. In this study, we surveyed P. olseni infection in juvenile Manila clam occurring on two tidal flats on the Taean coast. Ray’s fluid thioglycollate medium assay (RFTM) revealed that P. olseni infection was not limited to the adult clams, and the juvenile and small-sized clams are also infected by P. olseni. As young as four-month-old juveniles from Jugyo tidal flat were infected by P. olseni, with the prevalence (i.e., percentage of the infected individuals) of 75.0% and the intensity of 7.77 × 105 cells g−1 wet tissue weight (WT). The adult Manila clams (SL > 30 mm) from Jugyo tidal flat showed a prevalence of 96.0%, and the intensity as 5.80 × 10 cells g−1 WT. The observed infection prevalence and intensity of the juvenile are somewhat comparable to those of the adult clams, suggesting that a high level of P. olseni infection in the juveniles may lead to mortality and a long term decline in the clam population density.

Oxidation of Hydrogen sulfide, Ammonia nitrogen and Nitrite nitrogen by Bacillus sp. Isolated from West Coast of Korea

In the aquaculture industry, the biological treatment using probiotics for eliminating hydrogen sulfide, ammonia nitrogen and nitrite nitrogen is receiving attention. In this study, Bacillus sp. TO-3, Bacillus sp. TO-10 and Bacillus sp. TO-12 were isolated from the west coast of Korea and oxidation ability of hydrogen sulfide, ammonia nitrogen and nitrite nitrogen were analyzed. Bacillus sp. TO-10 had high oxidation toward hydrogen sulfide by oxidizing 100% and Bacillus sp. TO-3 and TO-12 each had hydrogen sulfide oxidation of 49.53% and 69.03%. Bacillus sp. TO-10 and Bacillus sp. TO-12 had ammonia nitrogen oxidation approximately of 32.7 mg/L, while Bacillus sp. TO-3 had 11.4 mg/L of ammonia nitrogen oxidation. Bacillus sp. TO-3, Bacillus sp. TO-10 and Bacillus sp. TO-12 all had high oxidation toward nitrite nitrogen by oxidizing 100% of 137.46 mg/L nitrite nitrogen. Therefore, Bacillus sp. TO-3, Bacillus sp. TO-10 and Bacillus sp. TO-12 are possible probiotics used as water quality improvement of eliminating hydrogen sulfide, ammonia nitrogen and nitrite nitrogen.

Diversity and Plant Growth-Promoting Effects of Fungal Endophytes Isolated from Salt-Tolerant Plants.

Fungal endophytes are symbiotic microorganisms that are often found in asymptomatic plants. This study describes the genetic diversity of the fungal endophytes isolated from the roots of plants sampled from the west coast of Korea. Five halophytic plant species, Limonium tetragonum, Suaeda australis, Suaeda maritima, Suaeda glauca Bunge, and Phragmites australis, were collected from a salt marsh in Gochang and used to isolate and identify culturable, root-associated endophytic fungi. The fungal internal transcribed spacer (ITS) region ITS1-5.8S-ITS2 was used as the DNA barcode for the classification of these specimens. In total, 156 isolates of the fungal strains were identified and categorized into 23 genera and two phyla (Ascomycota and Basidiomycota), with Dothideomycetes and Sordariomycetes as the predominant classes. The genus Alternaria accounted for the largest number of strains, followed by Cladosporium and Fusarium. The highest diversity index was obtained from the endophytic fungal group associated with the plant P. australis. Waito-C rice seedlings were treated with the fungal culture filtrates to analyze their plant growth-promoting capacity. A bioassay of the Sm-3-7-5 fungal strain isolated from S. maritima confirmed that it had the highest plant growth-promoting capacity. Molecular identification of the Sm-3-7-5 strain revealed that it belongs to Alternaria alternata and is a producer of gibberellins. These findings provided a fundamental basis for understanding the symbiotic interactions between plants and fungi.

Molecular characterization of Urosporidium tapetis sp. nov., a haplosporidian hyperparasite infecting metacercariae of Parvatrema duboisi (Dollfus 1923), a trematode parasite of Manila clam Ruditapes philippinarum on the west coast of Korea

Recently, a putative new hyperparasitic haplosporidian in the genus Urosporidium was identified from metacercariae of the trematode Parvatrema duboisi infecting Manila clam Ruditapes philippinarum on the west coast of Korea. In this study, we applied small subunit ribosomal DNA (SSU rDNA) sequences as a marker to substantiate the phylogenetic relationship of the unidentified Urosporidium within the Order Haplosporida. In our phylogenetic analysis, the 1890 bp of SSU rDNA sequences obtained were closely related to a haplosporidian parasite forming a sister clade to Urosporidium group, although the gene sequences were only 89.22–89.70% similar to Urosporidium spp. Such molecular phylogenetic distance within the genus suggested that the unidentified Urosporidium is a new member of the genus. Accordingly, we report the unidentified haplosporidian hyperparasite as Urosporidium tapetis sp. nov.

Impact of derelict fishing gear on the seafloor integrity and benthic communities in the macrotidal flats from northern Gyeonggi Bay, west coast of Korea

Derelict fishing gear (DFG) is increasingly common in the Korean tidal flats due to intensive fishing activity and the lack of monitoring system to remove the DFG from the tidal flats. Despite the widespread occurrence of DFG in the tidal flats, little is known about DFG in terms of quantity, types, distribution, and the impact on the benthic ecosystem. Unmanned aviation vehicle (UAV)-assisted photogrammetry and high-precision leveling were conducted to characterize DFG in the macrotidal flat, south of Gangwha Island, west coast of Korea. High concentration of DFG occurs preferentially in the channel where nets with stakes were installed for catching fishes. Topographic relief around DFG is more rugged and pronounced in the lower intertidal zone than in the middle intertidal zone, suggesting more dynamic sedimentary processes related to DFG in the lower intertidal zone. The density of benthic species is nearly identical in the middle intertidal zone regardless of the presence of DFG. In contrast, the density of macrofauna in the lower intertidal zone nearly doubles at the area free of DFG compared to the area affected by DFG. The biomass and primary production of the microphytobenthos (MPB) are smaller in the lower intertidal zone than the middle intertidal zone but show no discernible trend related to the presence of DFG. Strong tidal currents in the lower intertidal zone induce larger vortices over DFG and promote rapid deposition and erosion around DFG, resulting in a more hostile condition for the benthic ecosystem. The present study showcased that UAV-assisted mapping provides an effective tool to characterize the distribution and physical disturbance caused by DFG in the macrotidal flats, which will be a breakthrough for the sustainable management of rapidly deteriorating tidal flats with poor accessibility.

Short Sea Shipping on the West Coast of Korea: Keys to Activating the Shipping Industry in Preparation for Korea Unification Era

This study aims to analyze information on vessel traffic between the two Koreas with a probability distribution for each route/vessel type. The study will then conduct an estimate for maritime transport patterns of inter-Korean trade in the future. To analyze the flow of inter-Korean coastal shipping, this study conducted visualization analysis of shipping status between North and South Korea by year, ship type, and port using navigation data of three years from Port Logistics Information System (Port-MIS) sources during 2006 to 2008, which saw the most active exchanges between the two governments. Also, this study analyzes shipping status between the two governments as a probability distribution for each port and provides the prospects for future maritime transport for inter-Korean trade by means of Bayesian Networks and simulation. The results of the analysis are as follows: i) when North-South routes are reopened, the import volume for sand from North Korea will be increased; ii) investment in the modernization of ports in North Korea is required so that shipping companies can generate profit through economies of scale; iii) the number of the operating vessels including container ships between the two governments is expected to increase like when the tensions and conflict on the Korean Peninsula was release, especially between Busan port in South Korea and Nampo port in North Korea; and iv) among container ships, transshipment containers imported and exported through Busan Port will be shipped to North Korea by feeder transportation.

Application of pseudo-3D Chirp sub-bottom profiler survey: a case study of ancient wooden shipwreck site, west coast of Korea

Chirp sub-bottom profilers (SBP) provide centi-to-decimetre resolution, seismic data with applications for various geophysical and geological purposes. To verify the field application of imaging of a buried target with a cost-effective and easy-to-apply pseudo-3D Chirp SBP survey, we explored the buried site of an ancient wooden shipwreck off the west coast of Korea before underwater excavations. The survey was conducted using a commercial 2D Chirp SBP system with a newly devised recording system that preserved the true polarity of the chirp signal. To produce high-resolution 3D Chirp SBP data from 2D Chirp SBP datasets recorded by the novel system, an optimal data processing sequence, consisting of a first phase of 2D data processing and a second phase of 3D data processing was designed. The first, 2D phase, included the estimation of a source sweep signature, cross-correlation, and deconvolution using an inverse filter. The resulting resolution of the 2D Chirp SBP data was better than that of the enveloped data provided by the commercial acquisition system. The second phase of 3D data processing included gathering 3D datasets, redistributing of ping positions, and static correction. To improve the consistency of the seismic events and reduce the repetitive corrections (swell, tidal, tie, and residual corrections), a static correction was based on multi-beam echo sounder data. The amplitude variation near the shipwreck was clearly apparent in the time slice from the final pseudo-3D Chirp SBP dataset with a bin size of 2.0 m (crossline) × 0.6 m (inline). Through 3D rendering, the buried ancient shipwreck with dimensions of 5 m (width) × 12 m (length) × 2 m (depth) was imaged successfully.

Effect of Open Boundary Conditions and Bottom Roughness on Tidal Modeling around the West Coast of Korea

The aim of this study was to investigate the effect of open boundary conditions and bottom roughness on the tidal elevations around the West Coast of Korea (WCK) using an open-source computational fluids dynamics tool, the TELEMAC model. To obtain a detailed tidal forcing at open boundaries, three well-known assimilated tidal models—the Finite Element Solution (FES2014), the Oregon State University TOPEX/Poseidon Global Inverse Solution Tidal Model (TPXO9.1) and the National Astronomical Observatory of Japan (NAO.99Jb)—have been applied to interpolate the offshore tidal boundary conditions. A number of numerical simulations have been performed for different offshore open boundary conditions, as well as for various uniform and non-uniform bottom roughness coefficients. The numerical results were calibrated against observations to determine the best fit roughness values for different sub-regions within WCK. In order to find out the dependence of the tidal elevation around the WCK on the variations of open boundary forcing, a sensitivity analysis of coastal tide elevation was carried out. Consequently, it showed that the tidal elevation around the WCK was strongly affected by local characteristics, rather than by the offshore open boundary conditions. Eventually, the numerical results can provide better quantitative and qualitative tidal information around the WCK than the data obtained from assimilated tidal models.

Protective effects of extracts from six local strains of <italic>Pyropia yezoensis</italic> against oxidative damage <italic>in vitro</italic> and in zebrafish model

Pyropia yezoensis has been used as functional food in East Asia, especially in Korea and Japan, for more than five hundred years. This study aims to evaluate the antioxidant effect of polyphenols and proteins-rich extracts from P. yezoensis (PPPs) against 2,2′-azobis (2-amidinopropane) dihydrochloride (AAPH)-induced oxidative cell damage. Among six Korean local strains obtained from Jinhae (JiH), Haenam (HN), Jangheung (JaH), Jindo (JD), Wando (WD), and Sinan (SA) areas, the extracts of P. yezoensis from SA and JD are relatively higher in polyphenols and proteins contents. SA showed the lowest IC50 scavenging activities against 1,1-diphenyl-2-picryl-hydrazyl and alkyl radicals and displayed protective effects against reactive oxygen species (ROS) in AAPH-induced Vero cells. Especially, the PPPs extracts from SA and JD showed protective activities against AAPH-induced apoptosis, as observed by nuclear staining with Hoechst 33342. Furthermore, in vivo studies of the SA extract in zebrafish showed significantly reduced ROS generation, lipid peroxidation, and cell damage. This is the first study, to our knowledge, to evaluate the antioxidant bioactivity of PPP in the Korean Peninsula using a zebrafish model. Due to SA and JD both located in the west coast of Korea, we deduced that the chemical content of the different PPP extracts was mildly influenced by their geographic location, and this alga has potential of protective activity against AAPH-induced ROS both in vitro and in vivo. Key words: antioxidant effect; Gim; polyphenols; proteins; Pyropia yezoensis; zebrafish

Short Sea Shipping on the West Coast of Korea: Keys to Activating the Shipping Industry in Preparation for Korea Unification Era

This study aims to analyze information on vessel traffic between the two Koreas with a probability distribution for each route/vessel type. The study will then conduct an estimate for maritime transport patterns of inter-Korean trade in the future. To analyze the flow of inter-Korean coastal shipping, this study conducted visualization analysis of shipping status between North and South Korea by year, ship type, and port using navigation data of three years from Port Logistics Information System (Port-MIS) sources during 2006 to 2008, which saw the most active exchanges between the two governments. Also, this study analyzes shipping status between the two governments as a probability distribution for each port and provides the prospects for future maritime transport for inter-Korean trade by means of Bayesian Networks and simulation. The results of the analysis are as follows: i) when North-South routes are reopened, the import volume for sand from North Korea will be increased; ii) investment in the modernization of ports in North Korea is required so that shipping companies can generate profit through economies of scale; iii) the number of the operating vessels including container ships between the two governments is expected to increase like when the tensions and conflict on the Korean Peninsula was release, especially between Busan port in South Korea and Nampo port in North Korea; and iv) among container ships, transshipment containers imported and exported through Busan Port will be shipped to North Korea by feeder transportation.

Rapid Change in Sedimentary Facies from Wave- to Tide-dominated Macrotidal Flat in the Sinduri Bay, West Coast of Korea

Yoon, H.H.; Chun, S.S., and Hong, S.H., 2020. Rapid change in sedimentary facies from wave- to tide-dominated macrotidal flat in the Sinduri Bay, west coast of Korea. In: Malvarez, G. and Navas, F. (eds.), Global Coastal Issues of 2020. Journal of Coastal Research, Special Issue No. 95, pp. 728-732. Coconut Creek (Florida), ISSN 0749-0208.Macrotidal wave-dominated coastal environments are widely distributed on the western open coasts of Korea, although various muddy intertidal flats occur also in the inner part of embayed areas influenced strongly by geomorphological factor. The surface sediment of wave-dominated sandflat and tidal beach, which are developed on the northern Sinduri Bay coast, consists mostly of very well sorted medium to fine sand. Swash bars, which are parallel to the coastline and continuously migrating landward, play the important role in the formation of this macrotidal sandflat. The surface sedimentary facies in this southern embayed area consists mostly of mud. The mud flat is very gentle in slope with slight concave-up profile, and dominantly shows a highly bioturbated mud facies. The distribution of surface sedimentary facies, slope profile, hydrodynamic analysis and the transport pattern of coarse-grained sediment show a rapid change in sedimentary facies with very narrow transition zone from wave-dominated sandflat facies to tide-dominated mudflat facies. Both wave- and tide-dominated coasts have been formed together within a small single geomorphological unit. The co-occurrence of different types of coasts and the rapid shift of sedimentary facies can be indicative of one of characteristics in the macrotidal open-coast depositional environment in which geomorphology, sediment supply and hydrodynamic factors have been closely associated within a relatively small bay area. Sedimentary processes in the two coastal sytems are separated and independent each other. The development of separated depositional systems are also evident even in cored sediments, indicating that the recent depositional setting has been continued much longer time.