West Coast Of Korea Research Articles

Verification of Beach Erosion in West Coast of Korea

Lee, Y.B.; Kim, H.D., and Kwak, K., 2018. Verification of Beach Erosion in West Coast of Korea. 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. 256–260. Coconut Creek (Florida), ISSN 0749-0208.The factors that cause the coastal erosion are different depending on where the wave field dominates and where the tide effect is large; however, most coastal erosion studies have been conducted on areas where waves are dominant. The west coast of Korea has maximum tide difference of more than 9 m. This study aided to examine the relationship between coastal erosion and the area where the effect on tide is large. The selected study field, Kkotji Beach, is a representative coastal tourist location on the west coast of Korea. Due to serious coastal erosion, sandy beach has been graveled and the number of tourist has decreased which resulted in great economic loss. In this study, field observations and numerical simulations were used simultaneously. For the field observations, beach profile measurement, sediment observation, wave observation, and tide and current observations were conducted to investigate and analyze the causes of the coastal erosion. Numerical simulations were used to consider both wave and tide by reproducing the coastal erosion phenomenon and compare to the field observations. The effects of the tide on coastal erosion were presented through the simulations. As a result, the suspected causes of the erosion of the Kkotji Beach are the W direction induced wave during the winter, reduction of the erosion control forest due to coastal development, and large tide difference.

The Community Structure and Grazing Rates of Meiobenthos in Chunsu Bay, West Coast of Korea

Min, W.-G.; Kwon, K.-G.; Rho, H.S., and Kim, D., 2018. The Community Structure and Grazing Rates of Meiobenthos in Chunsu Bay, West Coast of Korea. 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. 401–405. Coconut Creek (Florida), ISSN 0749-0208.The community structure and grazing rates of meiobenthos was studied in Chunsu bay on west coast of Korea. To examine feeding habit of major meiofaunal groups, grazing rate of nematodes and harpacticoid copepods was measured using the isotope-tracer (3H thymidine, 14C amino acid) method at 3 stations in subtidal area and 1 station in intertidal area of Chunsu bay. Time-serial measurement of grazing rate was made to elucidate the effects of day/night and tidal cycle on diel feeding rhythm of the animals. The number of culturable bacteria fluctuated from 1.73±0.25×105 to 18.23±1.17×105 CFU/cm3 during the study period, and was highest in October. The Concentration of Chl.a in the sediment at the study site was 18.0~168.2 mg/m2 in April and 36.6~111.0 mg/m2 in October. The most abundant meiobenthos was nematodes and followed by sarcomastigophorans, harpacticoid copepods. Density of meiobenthos were 5~1632 inds./10cm2 during the study period. The grazing rates of nematode varied 0.5~57.2%/h on bacteria and 0.4~53.3%/h on microalgae at the station in tidal flat. The grazing rates of harpacticoid copepods were 0.2~14.2%/h on bacteria and 0.3~12.2%/h on benthic microalgae at the station in tidal flat. In the subtidal area, the grazing rates of nematode were 33.4~82.5%/h on bacteria and 10.3~71.5%/h on microalgae and harpacticoid copepods were 0.2~14.2%/h on bacteria and 0.3~12.2%/h on benthic microalgae.

Plume Current Change by Seawall Construction for a Harbor Development in South Korea

Kim, M.-J.; Kim, C.-S.; Choi, B.-J., and Lee, S.-H., 2018. Plume Current Change by Seawall Construction for a Harbor Development in South Korea. 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. 126–130. Coconut Creek (Florida), ISSN 0749-0208.The present study investigates the effects of a seawall construction on the nearfield plume dispersal and surface circulation in the west coast of Korea where the Saemangeum tide dike (33 km long) had been constructed from 1993 to 2006 to reclaim the wide tidal flat in the riverine estuary. The plume water has since flowed out by the gate operation from the two sluices (11 km apart) in the southern dike to the offshore, which altered source location of the plume in the coastal sea. Recently a 3.5 km long seawall was constructed at 4 km offshore from the northern sluice. The changes of the plume current and surface circulation near the newly constructed seawall were examined using data set of High Frequency Radar-derived current (HFR-current), wind and sluice-outflow velocity in summer 2010 (before the seawall construction) and summer 2014 (under the seawall construction). It was found that construction of seawall evidently changed tidal plume dispersal pattern and nearfield distribution of monthly-mean plume current. Complex correlation and Empirical Orthogonal Function (EOF) analyses on the subinertial surface current, wind, and sluice-outflow velocity in summer 2010 and summer 2014 revealed that wind and outflow velocity are dominant factors controlling variations of the plume extension and coastal current.

Implications of Estuarine and Coastal Management in the Growth of Porphyra sp. in the Geum River Estuary, South Korea: A Modeling Study

Kim, H.-C.; Song, Y.-S.; Kim, Y.H.; Son, S.; Cho, J.-G.; Chang, W.K.; Lee, C.-H.; Nam, J., and Ryu, J., 2018. Implications of esuarine and coastal management in the growth of Porphyra sp. in the Geum River Estuary, South Korea: A modeling study. 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. 396–400. Coconut Creek (Florida), ISSN 0749-0208.Laver (Porphyra sp.) is one of macroalgae species that has been cultivated for the purpose of food consumption in the coastal areas of Korean Peninsula. In specific, Porphyra tenera Kjellman and Porphyra yezonensis Ueda are two major commercial species for aquaculture in the west coast of Korea. In this study authors employed an ecosystem modeling approach (Hadley et al., 2014) to simulate the nutrient physiology and growth of the laver in aquaculture facilities located in the vicinities of Geum River Estuary. Some of model coefficients and parameterizations were modified from the original version based on laboratory experiments, if necessary. In addition, authors calibrated and validated the Delft3D (https://oss.deltares.nl/web/delft3d) with long-term time series data from the area. The Delft3D is an open source modeling suite that can simulate hydrodynamics (temperature, salinity, flow fields), sediment transport and water quality variables (inorganic nutrients). As one of the end-point goals of the present study is to develop decision supporting tools that can be used by coastal managers, the macroalgae growth model was coupled with the Delft3D in order to predict effects of episodic climatic events and/or upstream water management decisions on the estuarine ecosystem. Temperature, salinity and nitrogen loadings estimated from the Delft3D were used as input to the ecosystem model, and subsequent responses from Porphyra sp. were numerically simulated. Given thirteen scenario-based simulations, it is found that model simulated dissolved inorganic nitrogen concentrations do not change significantly for the same climatic condition. However, the maximum potential annual production of macroalgae is found to be more dependent on ammonium ion concentration.

The Application of Dynamic Tidal Power in Korea

Park, Y.H., 2018. The Application of Dynamic Tidal Power in Korea 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. 1306–1310. Coconut Creek (Florida), ISSN 0749-0208.Tidal power is attractive as a predictable renewable energy, but it requires a high tidal range. The west coast of Korea is a place where the extreme tidal range is observed, so various studies have been conducted. The largest tidal power, Sihwa Tidal Power Station was successfully built and operated there. However, subsequent projects have been postponed or cancelled due to environmental issues. Dynamic Tidal power (DTP) is an alternative way to a conventional tidal barrage system. Because DTP has to be a huge structure to produce diffraction of tides, it was tested by a numerical model. The 2D numerical model ADCIRC was used in the simulation. DTP was simulated in the largest tidal range of the Korean coast and it was examined in various ways. DTP generates power by the phase difference of tide and it is available even in a small tidal range. The tidal difference between the front and back of DTP becomes maximized on 180 degrees out of phase theoretically. Though the phase difference also increased with the length of DTP structure, it could not reach 180 degrees out of phase even at the DTP length of 50 km. Because the length of DTP structure should be longer than tens of kilometers considering the length of tide, it may cause economic and environmental issues. The phase difference was varied along DTP and it was increasing as the location of measurement moved closer to the coast. When the required length of DTP is optimized, it would be more practical. The study focused on the reduction of the DTP length and some shapes were suggested finally.

The Effects of Nourishments Using the Grain-Size Trend Analysis on the Intertidal Zone at a Sandy Macrotidal Beach

ABSTRACT Choi, T.-J.; Choi, J.-Y.; Park, J.-Y.; Um, H.-Y., and Choi, J.-H., 2018. The Effects of Nourishments Using the Grain-Size Trend Analysis on the Intertidal Zone at a Sandy Macrotidal Beach. 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. 426–430. Coconut Creek (Florida), ISSN 0749-0208. Byeonsan Beach is a typical macrotidal beach located at the west coast of Korea, which has been eroded continuously over the past decade since the construction of Saemangeum Dike. Starting from 2011, beach nourishment has been conducted annually on the Beach, with about 8 × 103 m3 of well sorted medium sands over the intertidal flat area. Primary purposes of this study are to understand the pattern of sediment transport using the grain-size trend analysis (GSTA) proposed by Gao and Collins (1992), and to evaluate the effect of nourishment procedures. Because of the mons...

한국 서해안 적황색 반고결 퇴적층의 특징과 형성 연대에 관한 논의: 증도 우전해안 퇴적층과의 대비

한국 서해안 적황색 반고결 퇴적층의 특징과 형성 연대에 관한 논의: 증도 우전해안 퇴적층과의 대비

서해안 중남부 바지락 어장의 서식환경과 종패 발생 특성

서해안 중남부 바지락 어장의 서식환경과 종패 발생 특성

Plant distribution along an elevational gradient in a macrotidal salt marsh on the west coast of Korea

The distribution of halophytes in salt marshes is generally determined by environmental gradients, and it is important to identify the principal factors involved. This study recorded how marsh plants, which have received limited attention, were distributed along elevational gradients, and investigated the environmental factors affecting their distribution on the Siheung Tidal Flat, which has one of the largest tidal ranges in the world. Plant and soil samples were collected in September 2015 from 203 plots that had been randomly selected in the intertidal zone. Soil salinity in the high-elevation plots varied over a wide range. Each halophyte species had a distinct zonation according to elevation. Cluster analysis classified plots into four clusters reflecting plant community composition (Cluster 1 at high elevation, defined by Suaeda glauca, Zoysia sinica, and Phragmites australis; Cluster 2 at mid-high elevation, defined by Phacelurus latifolius; Cluster 3 at low elevation, defined by Suaeda japonica; Cluster 4 at mid-high elevation, defined by Carex scabrifolia). Non-metric multidimensional scaling indicated that the distribution of S. japonica was strongly influenced by elevation and flood frequency, whereas that of P. latifolius was negatively influenced by soil salinity and soil cations (Na+, Mg2+, K+, Ca2+). Understanding the relationship between halophyte distribution and environmental factors along elevational gradients in a natural salt marsh provides important ecological information that may contribute to salt marsh restoration.

High parasite burden increases the surfacing and mortality of the Manila clam (Ruditapes philippinarum) in intertidal sandy mudflats on the west coast of Korea during hot summer

BackgroundOver the past few decades, mass mortality events of Manila clams have been reported from several tidal flats on the west coast of Korea during hot summers. During such mortality events, once clams simultaneously surface, they fail to re-burrow, perishing within a week. The present study aimed to identify the possible causes of the mass mortality of this clam species by investigating the Perkinsus olseni parasite burden and immune parameters of surfaced clams (SC) and normal buried clams (NBCs) when sea water or sediment temperature in the study area varied from 25 °C to 34 °C from late July through mid-August 2015.ResultsWe collected 2 groups of clams distributed within a 10-m2 area when a summer clam mortality event occurred around Seonyu-do Island on the west coast of Korea in 2015. The clams were collected 2 days after they surfaced on the sediment and still looked healthy without any gaping. The clams were transported to the laboratory, and we compared P. olseni infection intensity and cell-mediated hemocyte parameters between the NBCs and SCs. SCs showed significantly higher levels of P. olseni burden, lower condition index, and lower levels of cell-mediated immune functions than those of NBCs.ConclusionsOur study suggests that high P. olseni infection weakens Manila clams’ resistance against thermal stress, causing them to surface. We surmise that the summer mass mortality of Manila clams on the west coast of Korea is caused by the combined effects of high P. olseni infection levels and abnormally high water temperature stress.

Flux and distribution of methane (CH4) in the Gunsan Basin of the southeastern Yellow Sea, off the Western Korea

ABSTRACTThe flux and distribution of methane (CH4) was investigated in the seawater column at 14 stations in the Gunsan Basin, the southeastern part of Yellow Sea from 2013 to 2015. Here CH4 is concentrated 2.4–4.7 (3.4 ± 0.7) nM in the surface and 2.5–7.4 (5.2 ± 1.7) nM in the bottom layer. The CH4 saturation ratios ranged from 65.5% to 295.5% (162.6 ± 68.7), comprising the mean sea-to-air CH4 flux of 3.8 to 25.3 (15.6 ± 5.5) µM m−2d−1. Methane concentration was largely different in the upper and the lower seawater layers that is separated by the thermocline of which depth is variable (20–60 m) depending on the time of sampling. The concentration of seawater dissolved CH4 is high between the bottom surface of the thermocline layer and the sea floor. Generally it tends to decrease from the south-westernmost part of the basin toward the west coast of Korea. This distribution pattern of CH4 seems to result from the CH4 supply by decomposition of organic matters produced in the upper seawater layer that is superimposed by the larger supply from the underlying sediment layer especially beneath the thermocline. The latter is manifested by ubiquitous CH4 seeps from the seafloor sediments.

New Records of the Diatom Species (Bacillariophyta) from the Seaweed and Tidal Flats in Korea

This research was conducted to find the indigenous diatom species unrecorded in Korea from February to December 2016. The samples were taken at 28 sites of the coastal regions on the west coast of Korea and Jeju Island. Diatoms were collected mostly from sand and mud of tidal flats, including gravel, seaweed on the bottom and macrophytes floating in the seawater. Diatom specimens were observed by means of light and scanning electron microscopy. Twenty one species were discovered and added as new specimens to the Korean diatom flora, which are divided into 9 orders, 12 families, and 16 genera. The list and photographs of the species are included with the description of the morphological characteristics and distribution in Korea.

The role of fluid mud in the formation of extensive mud sheets during summer on the Duuri macrotidal flat, west coast of Korea

On the Duuri macrotidal flat along the west coast of Korea, mud sheets exceeding 20 cm in thickness form during summer, and are completely eliminated in the course of the following winter. This cyclical seasonal deposition/erosion of mud on the extensive intertidal flat of Korea has to date not been plausibly explained. To elucidate the responsible mechanism, vertical profiles of suspended sediment concentrations (SSCs) were obtained from March to August 2008 using an ASM-IV, which comprises a vertical array of OBS sensors mounted within a 1.44-m-long pole. The measurements reveal that a high-concentration mud layer begins to develop in mid-May, and reaches concentrations over 10 g/l (fluid mud) by August. SSCs are observed to be generally higher at spring tide than at neap tide. The fluid mud (SSCs >10 g/l) clearly responds to wave action: the calm period being characterized by a two-layer profile, whereas a gradational one-layer profile during the rough summer season. The fluid mud sheet blanketing the exposed flat is supposed to be semi-consolidated mainly by organic processes and solar radiation during low-water slack tide. The differential response of the fluid mud to the variable seasonal wave-energy conditions thus plays a key role in the rapid and widespread formation of ephemeral mud flats in the study area during summer. The available evidence, however, suggests that the summer mud sheet has a very low potential for preservation in the rock record.

Two new species of the genus Emertonia Wilson, 1932 from Korean waters (Copepoda, Harpacticoida, Paramesochridae).

Two new species of the genus Emertonia were found from the west coast of Korea. The first new species, E. koreana sp. n., is closely related to E. acutifurcata. However, the new species is clearly distinguished by the presence of two modified pinnate setae on the P5 baseoendopodal lobe. All body somites of the new species except for the last two urosomites have strongly developed hyaline frills forming quadrilateral lappets. The second new species, E. simplex sp. n., superficially resembles E. mielkei in the structure of antennary exopod (with five setae), and the shape of P5. However, this new species differs from its congener mainly by having a caudal ramus 3.5 times as long as width, and P1 enp-2 with two claw-like setae. In addition, a key to the worldwide species of Emertonia is provided.

Temporal and Spatial Variations in Sea Surface Temperature Around Boryeong off the West Coast of Korea From 2011-2012

Temporal and Spatial Variations in Sea Surface Temperature Around Boryeong off the West Coast of Korea From 2011-2012

Progressive change of tidal wave characteristics from the eastern Yellow Sea to the Asan Bay, a strongly convergent bay in the west coast of Korea

Although there have been studies on the tide in convergent bay (or estuary), the tide change in terms of phase speed, amplitude, and phase difference between elevation and tidal current from a coastal ocean to a convergent bay has not been clearly shown so far. This study systematically examines the change of tidal wave characteristics from the eastern Yellow Sea to the Asan Bay, a strongly convergent bay on the west coast of Korea, using observations and an analytical model. As the tidal wave propagates from the eastern Yellow Sea into the Asan Bay, the phase speed, amplitude, and phase difference between elevation and tidal current increase along the channel. Such a phenomenon represents a unique example of tide change from a coastal ocean to a convergent bay, indicating dominance of convergence over friction in the Asan Bay. Both analytically computed tidal amplitude and travelling time compare well with observations. In the Asan Bay, the influence of the reflected wave is only felt in the upper one fifth of the bay and is almost unperceivable in the rest of the bay. The analytical analyses presented in this paper are particularly useful for understanding the relative importance of channel convergence, bottom friction, and reflected wave on the tidal characteristics change along the channel and the proposed method could be applicable to other estuaries.

Environmental Impacts and Recovery After the Hebei Spirit Oil Spill in Korea.

The Hebei Spirit oil spill (HSOS) on December 7, 2007 was the worst oil spill recorded in Korea, with the release of approximately 10,900tons of crude oil and 375km of coastline polluted along the west coast of Korea. Cleanup operation was conducted by official and contract responders as well as volunteers for massive oil containment and removal of heavy accumulations of stranded oil. Together with the oil cleanup, a long-term environmental impact assessment (EIA) of the HSOS was initiated based on the Marine Environmental Management Act, which covers oil contamination in a multimedia environment, toxic effects on organisms, and ecosystem injury. This review summarizes the long-term monitoring results of HSOS EIA focused on (1) pollution status of seawater, sediment, and bivalves, (2) ecotoxicological effects, and (3) ecosystem recovery. Overall, concentrations of petroleum hydrocarbons in the environment indicated that their concentrations were well down to at or near background or pre-spill contamination levels at most sites after 1year. The potential toxic effects of residual oils in sediments have decreased to background levels in most coastal areas of Taean. The entire ecosystem in the most affected area of the Taean coasts appear to be considerably, but not fully, recovered at present, namely after 8years of the HSOS. The presence of lingering oil and elevated contamination levels at several sites still require continuous long-term monitoring.

Long-Term Monitoring of PAH Contamination in Sediment and Recovery After the Hebei Spirit Oil Spill.

Approximately 10,900t of crude oil was released 10km off the west coast of Korea after the collision between the oil tanker Hebei Spirit and a barge carrying a crane in December 2007. To assess the areal extent and temporal trends of PAH contamination, 428 sediment samples were collected from December 2007 through May 2015 for PAH analysis. Sedimentary PAH concentrations measured immediately after the spill ranged from 3.2 to 71,200ngg-1, with a mean of 3800ngg-1. Increases in PAH concentrations were observed at stations 7-23, which were heavily oiled due to tidal currents and northwesterly wind that transported the spilled oil to these locations. Mean and maximum PAH concentrations decreased drastically from 3800 to 88.5 and 71,200 to 1700ngg-1, respectively, 4months after the spill. PAH concentrations highly fluctuated until September 2008 and then decreased slowly to background levels. Reduction rate was much faster at the sandy beaches (k=0.016) than in the muddy sites (k=0.001). In muddy sediments, low attenuation due to low flushing rate in the mostly anaerobic sediment possibly contributed the persistence of PAHs. By May 2015 (~7.5years after the spill), mean and maximum PAH concentrations decreased by 54 and 481 times, respectively, compared with the peak concentrations. The sedimentary PAH concentrations in the monitoring area have returned to regional background levels.

Identification of a Bioactive Compound, Violacein, from Microbulbifer sp. Isolated from a Marine Sponge Hymeniacidon sinapium on the West Coast of Korea

오늘날 해양생물로부터 얻어진 미생물유래의 이차대사물질은 구조적, 생물학적으로 새로운 화합물의 주요한 자원이다. 그 중에서 해면동물과 미생물 관계는 생리활성 물질을 탐색하는데 가장 흥미있는 자원 중 하나로서 주목받아 왔다. 본 연구에서는 서해안 조간대에서 채집된 주황해변해면(Hymeniacidon sinapium)으로부터 분리된 세균 균주(Microbulbifer sp., 127CP-12)를 검토하였다. 배양된 세균은 자주색 색소를 생산하였으며, 색소생산의 최적 배양조건을 조사하였다. 최대 색소생산을 위한 미생물 배양조건은 25℃, pH 6.0, 3% NaCl임을 알 수 있었다. 추출용매는 에탄올과 메탄올에 비해 아세톤이 더 적절한 것으로 나타났다. 추출된 색소의 주요성분은 HLPC, NMR, MS, 그리고 UV 스펙트럼의 구조 분석을 통해 유용한 생리활성물질인 비올라세인으로 밝혀졌다. 본 연구는 해양미생물이 관여한 대사물질로부터 생리활성물질을 조사하는 연구기법을 서술함과 동시에 오늘날 변화하는 해양환경에서 해면동물과 미생물 관계의 생태학적 의의를 제시하고 있다.

Sediment reworking by a polychaete, Perinereis aibuhitensis, in the intertidal sediments of the Gomso Bay, Korea

Bioturbation, especially sediment reworking by the activities of macroinvertebrates, such as feeding and burrowing, is one of the major processes that affect the physical, chemical, and biological characteristics of marine sediments. Given the importance of sediment reworking, this study was designed to evaluate the sediment reworking rate of a polychaete, Perinereis aibuhitensis, which is dominant in the upper tidal flats on the west coast of Korea, based on quantification of pellet production during spring and fall surveys. The density of individuals was higher in fall than in spring, whereas, due to a difference in the proportion of adults between the two seasons, the morphometric dimensions of the worm and its pellets were significantly longer and heavier in the spring. Hourly pellet production per inhabitant and density were closely related, with pellet production gradually decreasing as density increased. Daily pellet production was much higher in spring than in fall, mostly due to an increase in daytime production. The sediment reworking rate of Perinereis was similar in the two seasons in which observations were made and depended on its density and the sediment reworking rate per individual. The overall sediment reworking rate of Perinereis was 31 mm yr−1 based on its density in the study area.