West Coast Of South Korea Research Articles

Response Prediction and Monitoring Feasibility of a Stow Net System Using Measured Environmental Data in the Southwest Coast of Korea

This paper investigates the response characteristics of a stow net under wave and current excitations, as well as the feasibility of its monitoring system to check net functionality and prevent loss of fishing gears. The stow-net model is based on one of existing types used in southwest coast of South Korea. The measured wave and current data there are acquired and inputted as environmental loads for numerical simulations. The Morison equation for a moving object with equivalent net model is utilized as the external-force estimator, which has been validated by many researchers regarding fish-cage studies. Since the modelling of all the net elements is inefficient in terms of computational time in time-domain simulations, cruder equivalent-drag net elements are devised with equivalent wet mass, projected area, and axial stiffness. The performance of stow net is highly influenced by current velocity. Stow nets submerge more in stronger currents, which results in less wave forces. The proposed monitoring system can provide useful information, such as net functionality and loss of stow net, using the minimum number of monitoring sensors.

Application of a Conceptual Ecological Model to Predict the Effects of Sand Mining around Chilsan Island Group in the West Coast of Korea

Chilsan Island Group, located on the west coast of South Korea, has been recognized as a critical breeding and nursery ground for endangered seabirds because food is abundant and human activity is low. Chilsan Island Group has been under protection as a Natural Monument (Article no. 389) since 1997, but attempts were made in 2004 to exploit the coastal sands around the islands. A conceptual ecological model (CEM) was employed with energy flow diagram (EFD) to predict the effects of sand mining on the islands’ ecosystem. The results showed that sand mining activities caused long-term damage to benthic ecosystems and threatened seabird communities by reducing fish populations throughout the food web. The changes in energy flow in the ecosystem due to sand mining operations predict that reduction in secondary production of benthic animal communities might reduce energy transfer to humans and seabirds by 30%. Different ranges of uncertainty provided by the Monte Carlo simulation lead to the conclusion that sand mining could bring about undesirable consequences. One concern is that such negative consequences would have a much more severe impact on seabirds than humans because seabirds cannot compete effectively against humans for the limited food sources. In this study, the complex interrelationships between ecosystem members were simplified and a CEM was established to clearly identify which elements would be affected. The CEM with EFD was found to be helpful in promoting communication between stakeholders, and it is expected to be widely used as a decisionmaking tool by public officials.

Annual spatio-temporal migration patterns of Hooded Cranes wintering in Izumi based on satellite tracking and their implications for conservation

BackgroundThe Hooded Crane (Grus monacha) is listed as a vulnerable species by IUCN. Knowledge about the migration of the Hooded Crane is still limited. Here we reported the spatio-temporal migration patterns of Hooded Cranes wintering in Izumi, Japan, as well as important stopover areas for their conservation.MethodsFour adult and five subadult cranes, all wintering in Izumi, Japan, were fitted with satellite transmitters (GPS–GSM system) at their stopover sites in northeastern China in 2014 and 2015. We analyzed the time and duration of adults and subadults in spring and autumn migration, as well as the time and duration they stayed in breeding and wintering ground. In addition, we analyzed the land use of the cranes in stopover areas.ResultsAdult cranes took much longer time to migrate both north in spring (mean = 44.3 days) and south in fall (mean = 54.0 days) compared with subadult cranes (15.3 and 5.2 days, respectively). However, the subadults had longer wintering (mean = 149.8 days) and nomadic (breeding season for adults) seasons (mean = 196.8 days) compared with adults (133.8 and 122.3 days, respectively). Three important stopover areas have been identified: the region around Muraviovka Park in Russia, the Songnen Plain in China, and the west coast of South Korea, where cranes spent most of their migration time (62.2 and 85.7% in spring and autumn, respectively). During migration, nomadic period and winter, Hooded Cranes usually stay in croplands for resting and feeding. In non-wintering season, less than 6% of stopover sites were located within protected areas.ConclusionOverall, our results contribute to understanding the annual spatio-temporal migration patterns of Hooded Cranes in the eastern flyway, and planning conservation measures for this species.

한국 탄도만 낙지 (Octopus minor) 의 자원생물학적 연구

한국 탄도만 낙지 (Octopus minor) 의 자원생물학적 연구

On the Response of Shallow-water Tidal Regime by Geological Characteristic of Waterway and Man-made Structures in a Macrotidal Estuary: Han River Estuary (Korea)

Yoon, B.I. and Woo, S.-B., 2018. On the response of shallow-water tidal regime by geological characteristic of waterway and man-made structures in a macrotidal estuary: Han River estuary (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. 16–20. Coconut Creek (Florida), ISSN 0749-0208.To understanding shallow-water (short- and long-term period than semidiurnal tide) tidal regime in a macrotidal estuary, Han River estuary (HRE), located on the west coast of South Korea, tidal harmonic constituents of 20 stations were analysed. The semidiurnal tide dominated HRE consists of two main waterways, which have complex geological characteristics. The shallow and narrow characteristics of waterway transform propagating astronomical tides from the open-sea to shallow tidal components such as overtides and compound tides. The shallow tide (e.g., M4, MS4, and MSf) is important factors, which is determined water and mass circulation in a macrotidal estuary. To find shallow-water tidal regime characteristic in this study, we suggest short- and long-term period of tidal form number using shallow tidal constituents. The short-term period of tidal form number covers a range from 0.02 to 0.43, and it increase 10 times larger in the upstream estuary than the open-sea. The long-period of tidal form number is small in the open-sea, but going upward to the estuary, the value increases by 10 times, and it shows 100 times greater than that of the open-sea at the upper region of Han River. Due to complex geological characteristics of waterway, the amplitude of astronomical tidal constituent rapidly decrease and shallow water tidal constituent sharply increase. The other rapid change of tidal constituent is caused by the influence of man-made structures (Singok underwater dam) in the lower tidal river. It is apparent that regional characteristic of tidal regime caused by geological effect and influence of man-made structure.

Feasibility study of new hybrid piled concrete foundation for offshore wind turbine

Offshore wind turbine energy has recently attracted significant attention and many researchers have attempted to develop cost-efficient offshore wind turbine support structures to reduce capital costs. This paper proposes a new hybrid support structure using driven piles that eliminates the disadvantages of conventional support structures for offshore wind turbines. The hybrid support structure proposed here is a piled concrete foundation (PCF) structure, which combines a concrete base with a steel shaft and is supported not only by gravity type foundations but also by driven piles. The soil was modeled as an elastic foundation, and the added mass was calculated using the Added mass method to determine the effects of water surrounding the support structure. To evaluate the feasibility of the PCF, quasi-static analysis, natural frequency analysis and seismic analysis were performed using environmental conditions at the Southwest Coast of Korea. In quasi-static analysis, the lateral displacement did not exceed the allowable displacement, and natural frequency analysis confirmed the superiority of the dynamic behavior of the PCF. Seismic evaluation through response spectrum analysis and time-history analysis demonstrated that the PCF is safe. The proposed PCF was confirmed to have sufficient structural stability for applications in real-site conditions in Korea. Optimization of the structure using the preliminary design resulted in an efficient structure that reasonably reduces fabrication costs.

Holocene relative sea-level changes inferred from multiple proxies on the west coast of South Korea

Understanding past relative sea-level (RSL) changes is crucial for predicting future coastal evolution, particularly within the context of accelerated melting of polar ice sheets due to global warming. RSL records are scarce in many regions along the Pacific coast. Here, we present a Holocene RSL curve for the west coast of South Korea based on detailed analyses of four sediment cores and the synthesis of existing sea-level index points without correction by tectonic, sediment compaction and other effects. Our record shows that the local sea level rose rapidly during the early Holocene and then fell gradually toward the present position during the late Holocene. An apparent sea-level highstand of ca. 1–2 m occurred 7–4 cal kyr B.P. A rapid sea-level rise of ~1.4 cm yr−1 during the early Holocene is a manifestation of polar ice sheet decay, while the apparent mid-Holocene sea-level highstand appears to be a signal of the hydro-isostasy of the far-field continental shelf. The result was confirmed by a glacial isostatic adjustment (GIA) model. Holocene RSL change on the west coast of South Korea was closely linked to global temperature and ice sheet decay, especially during the early Holocene. There is a close relationship between sea-level change in the study area and Laurentide Ice Sheet (LIS) decay.

Relationship between halophyte distribution and soil environmental factors in the west coast of South Korea

BackgroundThe objective of this study was to determine the relationship between soil environmental factors and halophyte distribution in the west coast of South Korea. Soils of our study sites were categorized into two groups: salt marsh and estuary marsh.ResultsSalinity was higher in the salt marsh group than that in the estuary marsh group. However, total nitrogen, silt, and clay contents were higher in the estuary marsh group than those in the salt marsh group. Although altitude had a wider range in the salt marsh group, the mean altitude was higher in the estuary marsh group than that in the salt marsh group. Annual halophytes of seed propagation species were distributed parallel to the coast line on salt marsh. Higher coverage of vegetation was found in the area closer to the coast line. Plant density was higher near dead parental plants in estuary marsh, showing less difference in area that was more distant from the coast line.ConclusionsResults of canonical correspondence analysis (CCA) for vegetation distribution and sediment environmental factors and germination analysis in the coast line showed significant relationship with halophyte distribution. Therefore, they can be used as an indicator of coastal plant movement due to sea level rise.

Growth, reproduction and recruitment of Silvetia siliquosa (Fucales, Phaeophyceae) transplants using polyethylene rope and natural rock methods

Silvetia siliquosa is an ecologically and commercially important brown alga that is harvested from its natural habitats, but its population has recently been diminishing along the Korean coast. To develop new techniques for algal population restoration, we tested two newly developed transplantation methods (using polyethylene ropes and natural rock pieces) at two study sites, Gwanmaedo and Yeongsando, on the southwest coast of Korea, from May to November 2014. The transplants on polyethylene ropes showed significantly greater survival, maturity, and growth than those on natural rocks at both study sites. Newly recruited juveniles (<3 cm) of S. siliquosa increased remarkably from May to December near the transplants on polyethylene ropes and natural rocks. Therefore, we suggest that transplantation using polyethylene ropes is more effective than using natural rocks to restore the population of S. siliquosa in Korea.

Integrated sedimentological and ichnological characteristics of a wave-dominated, macrotidal coast: a case study from the intertidal shoreface of the Dongho coast, southwest Korea

Generalized coastal facies models invariably assume that tidal flats and intertidally exposed shorefaces along macrotidal coasts are tide-dominated. Recent advances in coastal sedimentology, however, have revealed that wave-dominated macrotidal flats also occur in a wide range of coastal settings, in particular where tidal modulation forces the lateral translation of the wave-affected zone across the tidally exposed shoreface with the rising tide. Despite tidal modulation, the depositional character in the latter case (abundant storm deposits) exhibits a high degree of similarity with conventional subtidal shorefaces, implying that it is inherently difficult to distinguish between the two coastal systems in the rock record. In the present study, integrated sedimentological and ichnological data from the Dongho coast, which is located along the southwest coast of Korea, provide valuable information for the establishment of facies criteria that can assist in the recognition of such coastal deposits. In fact, the sedimentary character of the study area, which is dominated by an abundance of wave-formed structures, resembles that generally associated with subtidal shorefaces. In addition, the depositional processes responsible for sediment accumulation are, in the present case, also strongly influenced by pronounced seasonal variations in wave energy. In this context, the study has revealed a number of major features that appear to be characteristic of wave-dominated intertidal flats and shorefaces: (1) firmground muds may be encountered on the beach face, where intense swash-backwash motions are dominant; (2) the thickness of storm deposits decreases landward, reflecting the progressive decrease in wave energy; (3) ichnologically, there is an offshore shift in the dominance of trace fossils from the Skolithos ichnofacies, including Ophiomorpha, Thalassinoides and Psilonichnus, to a proximal expression of the Cruziana ichnofacies, which includes Siphonichnus and Asterosoma; (4) compared with subtidal shorefaces, the overall ichnological suite is represented by a substantial reduction in diversity and less uniformly distributed burrows. Although these findings have not yet been applied to the rock record, they should nevertheless assist in the distinction between corresponding coastal deposits.

Impact of Salinity Change on Water Quality Variables from the Sediment of an Artificial Lake under Anaerobic Conditions

Artificial reservoirs are created by dike construction in coastal areas to secure the agricultural water supply on the west coast of South Korea. These systems are found to retain brackish characteristics until total desalination is achieved. To evaluate the effects of salinity on the organic substances released from the sediment, a laboratory water-sediment column experiment was conducted to assess associated changes in water quality variables such as the sediment oxygen demand (SOD), chemical oxygen demand (COD), and concentrations of nitrogen (N) and phosphorus (P). Under high salinity conditions, the release of N from the sediment was promoted with the enhancement of SOD and COD. This trend was accounted for by the response of the microorganisms (cell breakdown of algae and suppression of metabolic activity). Our results suggest that chemicals (N, P, and COD) released from sediment and its overall impact on the water quality of a brackish lake should vary depending on the temporal and spatial dynamics of the salinity.

Last interglacial to Holocene sedimentation on intertidal to subtidal flats revealed by seismic and deep-core sediment analyses, southwest coast of Korea

Over the past two decades, tidal flats in the west coast of Korea (eastern Yellow Sea) have been extensively investigated to reveal sedimentation and stratigraphic evolution coupled with sea level changes. In spite of such efforts, their sedimentary record and evolution pattern particularly in the deeper subtidal area are relatively little documented. To expand and fulfill our knowledge on sedimentation history from last interglacial to the Holocene, three drilled cores (up to ca. 28 m in length) and Chirp seismic profiles obtained from the subtidal zones along the southwestern coast of Korea were examined, with supplementary OSL and 14C-AMS age dates. Based on the sedimentary facies analysis correlated with seismic units, the subtidal deposits can be divided into four units: Unit I) basal fluvial deposit (MIS 6?), Unit II) tidal deposits (MIS 5e), Unit III) transition deposits between salt marsh and oxidized inland coastal dune (early Holocene), and Unit IV) Holocene tidal deposits, in ascending order. These units can be then grouped into two sedimentary sequences, a lower sequence S1 (Unit I and II) and an upper S2 (Unit III and IV) separated by an unconformable surface, being responded to two cycles in sea-level fluctuations. Each sequence started with non-marine deposits formed during lowstand in sea-level, and then overlain by tidal successions deposited during transgression. The feature thus indicates two tidal deposits, i.e., last interglacial and the Holocene in ages, preserved in the macrotidal west coast of Korea, possibly being major constituents of coastal successions to be survived in the records. This can be used to correlate with other marine strata in the western (Chinese) Yellow Sea since the last interglacial.

Holocene environmental change inferred from multiple proxies in the mouth of Gomso Bay on the west coast of South Korea

AbstractA sediment core (14DH-C01) obtained from the mouth of Gomso Bay, on the west coast of South Korea, was used to obtain high-resolution palynomorph, grain-size, and14C age data to investigate the Holocene sedimentary environment. The results indicated a transgressive depositional process with four stages controlled by sea-level change, as follows: river-dominated fluvial deposition from the early Holocene to 8.48 cal ka BP; tide-dominated tidal channel fill transgression from 8.48 to 8.08 cal ka BP; tide- to wave-dominated tidal channel fill transgression from 8.08 to 6.98 cal ka BP; and wave-dominated marine transgression from 6.98 cal ka BP to the present. Tidal channel filling was the primary mid-Holocene depositional process, accounting for the high sedimentation rate observed. The different hydrodynamics of the river-dominated, tide-dominated, tide- to wave-dominated, and wave-dominated processes following the changes in sea level may have controlled the transgressive depositional process. This transgressive sedimentary model differs from those of other large river mouth areas (e.g., the Changjiang River) since the mid-Holocene, perhaps resulting from the limited sediment supply in the study area.

Integrated change detection and temporal trajectory analysis of coastal wetlands using high spatial resolution Korean Multi-Purpose Satellite series imagery

A series of multispectral high-resolution Korean Multi-Purpose Satellite (KOMPSAT) images was used to detect the geographical changes in four different tidal flats between the Yellow Sea and the west coast of South Korea. The method of unsupervised classification was used to generate a series of land use/land cover (LULC) maps from satellite images, which were then used as input for temporal trajectory analysis to detect the temporal change of coastal wetlands and its association with natural and anthropogenic activities. The accurately classified LULC maps of KOMPSAT images, with overall accuracy ranging from 83.34% to 95.43%, indicate that these multispectral high-resolution satellite data are highly applicable to the generation of high-quality thematic maps for extracting wetlands. The result of the trajectory analysis showed that, while the variation of the tidal flats in the Gyeonggi and Jeollabuk provinces was well correlated with the regular tidal regimes, the reductive trajectory of the wetland areas belonging to the Saemangeum province was caused by a high degree of human-induced activities including large reclamation and urbanization. The conservation of the Jeungdo Wetland Protected Area in the Jeollanam province revealed that effective social and environmental policies could help in protecting coastal wetlands from degradation.

Genetic diversity and population structure of the Black-faced Spoonbill (Platalea minor) among its breeding sites in South Korea: Implication for conservation

The endangered Black-faced Spoonbill Platalea minor has experienced drastic reductions in population size, geographic distribution, and habitat availability throughout East Asia. In the present study, we examined population genetic structure and genetic diversity of Black-faced Spoonbills inhabiting five sites off the west coast of South Korea encompassing a few of its major breeding sites. Ten microsatellite loci and the mitochondrial sequence were used to assess patterns of genetic variation based on 63 individuals. Three ND2 haplotypes were found among 61 individuals; the remaining two were identified as Eurasian Spoonbills, revealing an unexpected hybridization between these two species having different ecological niches in South Korea—the Eurasian Spoonbill overwinters in inland areas, whereas the Black-faced Spoonbill inhabits coastal areas during the summer. Analyses of microsatellite variation revealed no discrete population structure among the five breeding sites but very weak genetic differentiation among geographically distant regions. Assignment tests identified several possible migrants among sites. Our findings suggested that Black-faced Spoonbills from the five breeding sites could be managed as a single population and highlighted the importance of conserving the populations from Maedo, Suhaam, and Namdong reservoir, which are geographically close and have retained high levels of genetic diversity and large populations.

Subtidal Macrobenthic Community in Shia Sea, Southwest Coast of Korea

Subtidal Macrobenthic Community in Shia Sea, Southwest Coast of Korea

Urinary oxidative stress biomarkers among local residents measured 6years after the Hebei Spirit oil spill.

In December 2007, the Hebei Spirit oil spill occurred on the west coast of South Korea. Association between crude oil exposure and the levels of urinary oxidative stress biomarkers was reported among the local residents, 1.5years after the accident. The aim of this study was to follow-up possible longer-term effects of the oil spill among the residents near the oil spill. Six years after the accident, urinary oxidative stress biomarkers of the residents were associated with surrogates of oil exposure. The target subjects were divided into two groups based on the distance of their residence to the spill site, i.e., those near the spill site ('Near' group, n=476), and those far from the spill ('Far' group, n=152). A questionnaire was administered by trained interviewers or self-reporting, and demographic information and other parameters of the participants, such as socioeconomic status, smoking and drinking behaviors, disease history, and duration of clean-up activities after the spill, were collected. The participants' levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA) in 12 h urine samples were measured as indicators of oxidative DNA damage and lipid peroxidation, respectively. A general linear model was used for statistical analysis. Urinary MDA and 8-OHdG levels measured from 'Near' group, i.e., geometric mean of 2.19μmol/g creatinine, and 5.41μg/g creatinine, respectively, were higher than those of 'Far' group. Especially, urinary 8-OHdG levels in the 'Near' group were significantly higher than those of 'Far' after adjusting relevant covariates. In addition, the duration of clean-up activities showed a significant association with both urinary 8-OHdG and MDA levels. Even 6years after the oil spill, positive associations between oxidative stress biomarkers and surrogates of oil exposure were evident. While the present study design lacks biomarkers of exposure, the results of this study suggest that the consequences of oil pollution may last for years.

Assessment of potential biological activities and distributions of endocrine-disrupting chemicals in sediments of the west coast of South Korea

The west coast of Korea has experienced environmental deterioration for more than half a century. In the present study, we specifically aimed to: i) evaluate potential toxicities of contaminants in sediments that cause effects mediated through the aryl hydrocarbon receptor (AhR) and estrogen receptor (ER); ii) determine spatio-temporal distributions of polycyclic aromatic hydrocarbons (PAHs) and alkylphenols (APs); and iii) identify causes of greater potencies of samples. From 2010 to 2014, sediments were collected from 12 major estuarine and coastal regions along the west coast of South Korea. In vitro cell bioassays were performed to determine AhR- and ER-mediated potencies using H4IIE-luc and MVLN cells, respectively. Fifteen PAHs and six APs in sediments were identified by GC/MSD. Results of bioassays generally showed a low-to-moderate degree of contamination, however, greater AhR- and ER-mediated potencies were measured at some locations. Concentrations of PAHs and APs varied among locations, which indicated that sources were independently affected by the surrounding environment (e.g., industrial complex and cities). Results of bioassays were generally well correlated with concentrations of putative causative chemicals. Benzo[k]fluoranthene, dibenz[a,h]anthracene, and benzo[b]fluoranthene were the major AhR agonists, explaining approximately 30% of the bioassay-derived benzo[a]pyrene equivalent concentration (BaP-EQ). Unknown AhR and ER agonists and potential mixture effects remain in question. Overall, the present study provides baseline information on chemical contaminations and potential toxicity of sediments in a fairly wide geographical region of the west coast of South Korea.

The radius of influence of a combined method of in situ air sparging and soil vapor extraction in the intertidal sediments of Gomso Bay on the west coast of South Korea.

BackgroundIn situ air sparging (IAS) was undertaken at sites in the tidal flats of Mandol and Hajeon, on the west coast of South Korea, to estimate variations in the radius of influence (ROI).ResultsThe Mandol core sample consisted of sand and muddy sand 1.6–3.4 Phi (average 2.3 Phi) and contained water (average 15.10 %). The Hajeon core sample consisted of muddy sand, sandy silt, and muddy sandy gravel 1.31–4.44 Phi (average 3.11 Phi) and contained water (average 19.77 %). These sites differ in their sedimentary and geochemical characteristics. At the Mandol site, no H2S or combustible gas was detected during a 48-h sampling period, except for some volatile organic compounds (0.1–2.0 ppm) at the monitoring well during the initial 30 min. At the soil vapor extraction wells, CO2 and O2 varied by 850 ppm (690–1540 ppm) and 0.5 % (20.4–20.9 %), respectively. At the Hajeon site, CO2 and O2 varied from 580 to 1250 ppm and 20.6 to 20.9 %, respectively, during the 48-h sampling period.ConclusionsAt the Mandol site, an oxygen concentration of 20.6 % was assumed as the effective concentration, and the ROI was estimated to be 128.0 cm. However, at the Hajeon site the ROI was estimated to be 85.7 cm. The smaller effective ROI at the Hajeon site was likely caused by the thin aquifer and thin screens of the sparing well. This estimated ROI show that the remediation effectiveness varies greatly as a heterogeneities and anisotropies in the porous sediments. Besides, injection pressure, flow rate, pulsing or continuous mode, and the range of intrinsic permeability for most important characteristic of sediment (soil) type impacted the ROI. Therefore, the IAS method is more effective at a pervasive air flow sediments such as Mandol, which consists of sand and muddy sand than at a channelized site such as Hajeon.Electronic supplementary materialThe online version of this article (doi:10.1186/s40064-016-3026-3) contains supplementary material, which is available to authorized users.

Respiratory Health of the Children in the Hebei Spirit Oil Spill

Introduction In December 2007, The oil spill from the Hebei Spirit contaminated the west Coast of South Korea. We evaluated the respiratory effects of oil spill exposure on children who were born in accident site (Taean). Methods Study subjects consisted of 80 children (49 boys, 31 girls) born in Taean and 25 children (10 boys, 15 girls) born in others city. All subjects completed a modified International Study of Asthma and Allergies in Childhood questionnaire. A health examination, pulmonary function test such as FVC and FEV1 administered. Results Mean of Forced Vital Capacity (FVC) were 93.8±0.19%, 98.5±0.15% the children born in Taean and other city, respectively. Mean of Forced Expiratory Volume in one second (FEV1) were 94.4±0.22%, 98.7±0.17% the children born in Taean and other city, respectively. The FVC and FEV1 was lower distribution in children who were born oil spill area than in those who born other city, but not significantly different between the two groups. Conclusions Our study did not show a significant difference between high exposed group(born Taean) and low exposed group. It is still important to have investigated children respiratory health effect long-term. Therefore continuous monitoring of children in Taean is needed.