• Korean Journal of Ecology and Environment
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• v.54 no.3
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• pp.209-220
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• 2021

Pacific herring, Clupea pallasii, a keystone species with significant ecological and commercial importance, is declining globally throughout much of its range. While traditional fishing equipment methods remain limited, new sensitive and rapid detection methods should be developed to monitor fisheries resources. To monitor the presence and quantity of C. pallasii from environmental DNA (eDNA) extracted from seawater samples, a pair of primers and a TaqMan^® probe specific to this fish based on mitochondrial cytochrome b (COB) sequences were designed for the real-time PCR (qPCR) assay. The combination of our molecular markers showed high specificity in the qPCR assay, which affirmed the success of presenting a positive signal only in the C. pallasii specimens. The markers also showed a high sensitivity for detecting C. pallasii genomic DNA in the range of 1 pg~100 ng rxn^-1 and its DNA plasmid containing COB amplicon in the range of 1~100,000copies rxn^-1, which produced linear standard calibration curves (r²=0.99). We performed a qPCR assay for environmental water samples obtained from 29 sampling stations in the southeastern coastal regions of South Korea using molecular markers. The assay successfully detected the C. pallasii eDNA from 14 stations (48.2%), with the highest mean concentration in Jinhae Bay with a value of 76.09±18.39 pg L^-1 (246.20±58.58 copies L^-1). Our preliminary application of molecular monitoring of C. pallasii will provide essential information for efficient ecological control and management of this valuable fisheries resource.

• Korean Journal of Remote Sensing
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• v.37 no.5_2
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• pp.1229-1234
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• 2021

GOCI-II, which succeeded the mission of GOCI, was successfully launched in February 2020 and is in operation. GOCI-II is expected to be highly useful in a wide range of fields, including detailed changes in the coastal seawater environment using improved spatial and spectral resolution, increased number of observation and full disk observation mode. This special issue introduces the assessment of the current GOCI-II data quality and the studies on the accuracy improvement and applications at this time of one year after launch and data disclosure. We expect that this issue can be an opportunity for GOCI-II data to be actively utilized not only in the ocean but also in various fields of land and atmosphere.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.57 no.3
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• pp.214-227
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• 2021

The distribution of tidal current and tidal induced residual current, topographical eddies and tidal residual circulation in the waters surrounding the Geumo Island-An Island channel were identified through numerical model experiments and vorticity balance analysis. Tidal current flows southwest at flood and northeast at ebb along the channel. The maximum flow velocity was about 100-150 cm/s in neap and spring tide. During the flood current in the neap tide, clockwise small eddies were formed in the waters west of Sobu Island and southwest of Daebu Island, and a more grown eddy was formed in the southern waters of Geumo Island in the spring tide. A small eddy that existed in the western waters of Chosam Island during the ebb in neap tide appeared to be a more grown topographical eddy in the northeastern waters of Chosam Island in spring tide. Tidal ellipses were generally reciprocating and were almost straight in the channel. These topographical eddies are made of vorticity caused by coastal friction when tidal flow passes through the channel. They gradually grow in size as they are transported and accumulated at the end of the channel. When the current becomes stronger, the topographic eddies move, settle, spread to the outer sea and grow as a counterclockwise or clockwise tidal residual circulation depending on the surrounding terrain. In the waters surrounding the channel, there were counterclockwise small tidal residual circulations in the central part of the channel, clockwise from the northeast end of the channel to northwest inner bay of An Island, and clockwise and counterclockwise between Daebu Island and An Island. The circulation flow rate was up to 20-30 cm/s. In the future, it is necessary to conduct an experimental study to understand the growth process of the tidal residual circulation in more detail due to the convergence and divergence of seawater around the channel.

• Journal of Hydrogen and New Energy
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• v.30 no.3
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• pp.282-288
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• 2019

When liquefied natural gas (LNG) is vaporized to form natural gas for industrial and household consumption, a tremendous amount of cold energy is transferred from LNG to seawater as a part of the phase-change process. This heat exchange loop is not only a waste of cold energy, but causes thermal pollution to coastal fishery areas by dumping the cold energy into the sea. This project describes an innovative new design for reclaiming cold energy for use by cold storage warehouses (operating in the 35 to $62^{\circ}C$ range). Conventionally, warehouse cooling is done by mechanical refrigeration systems that consume large amounts of electricity for the maintenance of low temperatures. Here, a closed loop LNG heat exchange system was designed (by simulator) to replace mechanical or vapor-compression refrigeration systems. The software PRO II with PROVISION V9.4 was used to simulate LNG cold energy, gas re-liquefaction, and the vaporized process under various conditions. The effects on sensible and latent heats from changes to the array type of heat exchangers have been investigated, as well as an examination of the optimum.

• Journal of Ocean Engineering and Technology
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• v.35 no.1
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• pp.82-90
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• 2021

Owing to the advantages of assuring the best views and seawater exchange, submerged breakwaters have been widely installed along the eastern coast of Korea in recent years. It significantly contributes to promoting the advancement of shorelines by partially inhibiting incident wave energy. Observations were carried out by a pressure-type wave gauge in the Bongpo Beach to evaluate the coefficients of wave transmission via a submerged breakwater, and the results obtained were compared with those of existing conventional equations on the transmission coefficient derived from hydraulic experiments. After reviewing the existing equations, we proposed a transmission coefficient equation in terms of an error function. Although it exhibited robust relationships with the crest height and breaking coefficient, deviations from the observed data were evident and considered to be triggered by the difference in the incident wave climate. Therefore, in this study, we conducted a numerical experiment to verify the influence of wave period on the coefficients of wave transmission, in which we adopted a parabolic-type mild-slope equation model. Consequently, the deviation from calculated results appears to practically cover all deviation range in the observed data. The wave period and direction of the incident wave increased, the transmission coefficient decreased, and the wave direction was determined to demonstrate a relatively significant influence on the transmission coefficient. It was inferred that this numerical study is expected to be used practically in evaluating the design achievement of the submerged breakwater, which is adopted as a countermeasure to coastal beach erosion.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.615-625
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• 2021

The coastal areas around Palau Island and Tonga Island, near the Pacific equator, consist of coral reefs, mangrove and seaweed. In particular, understanding the optical properties of sea surface water in coral reef habitats helps improve the accuracy of remote sensing based habitat mapping and identify tropical ecosystem characteristics. Here, we collected spectral characteristics of sea surface water of Palau Island and Tonga Island and analyzed the concentration of suspended matters, absorption coefficient, and remote sensing reflectance to understand the seawater characteristics of the coral reef habitats. Based on the results of the suspended matter concentration analysis, we developed and verified an empirical algorithm to derive the concentration from satellite data using remote sensing reflectance of three bands, 555, 625, 660 nm, showed a high determinant coefficient, 0.98. In conclusion, coral reef habitats in tropical regions are characterized by CASE-I water in terms of the marine optics with oligotrophic properties, and require monitoring using continuous collection and analysis of field data.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.4
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• pp.462-472
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• 2023

We investigated the physio-chemical and geochemical parameters in the spraying shellfish aquacultures (Yeoja and Gangjin Bay) to establish the systematic strategy for effective environmental management. Spatial variation of each parameter showed partially significant difference (P<0.05) between Yeoja and Ganjin Bay, inferring the discriminative progress (i.e., accumulation and degradation) of the autochthonous organic matter within the aquaculture environments. We additionally integrated various properties (e.g., water/sediment quality, natural hazard, and biological health) which may affect the biological growth within the aquaculture habitats based on the biogeochemical cycles related to environmental components and aquaculture species. We used a screening approach (i.e., one out-all out; OOAO) which can permit the assessment of the health levels of aquaculture species, the scoring for other parameters (seawater, sediment, and natural hazard) as three levels (excellent, moderate and poor) depending on the complex interactive properties occurring in the aquaculture environments. Actual, discriminative scores obtained via our case studies may confirm that these stepwise processes are effectively evaluated for optimal health conditions within the aquaculture habitats. Thus, this approach may provide valuable insights for effective environmental management and sustainable growth of aquaculture operation.

• Journal of Korea Water Resources Association
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• v.56 no.3
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• pp.165-171
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• 2023

The Nakdong Estuary Barrage is a tidal river environment where freshwater and seawater meet. This requires systematic monitoring of both surface water discharged from the estuary barrage and submarine groundwater discharge. In this study, upstream hydrograph and water balance analysis were used to calculate the change in water storage and discharge of the Nakdong Estuary Barrage. Submarine groundwater discharge was also calculated based on remote sensing-based digital elevation model data and hydrological modeling data, and compared with the estimated surface water discharge for analysis. Our proposed method can be efficiently applied to water resource management by utilizing remote sensing-based altimeter data other than field measurement. Because submarine groundwater discharge plays a significant role on the coastal environment as well as surface water discharge from an estuary barrage, studies on groundwatersurface water interactions in a river estuary should be sufficiently considered in monitoring the ecosystem of the Nakdong Estuary Barrage.

• Journal of the Health Care and Life Science
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• v.11 no.2
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• pp.465-470
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• 2023

This study aims to understand marine therapy through an overall review of the marine therapy industry and provide basic data for policy establishment on marine therapy based on this. Talasotherapy refers to the medical use of marine climate, seawater, marine mud, algae, sand and other marine extracts, which are beneficial components of the ocean for preventive and therapeutic purposes. Centers in Taean, Goseong, Uljin, and other marine healing pilot projects should be well combined with programs within rehabilitation clinics so that local tourism and marine healing programs can be combined, and how well the existing marine infrastructure is established is a very important factor. Establish legal and institutional foundations, inter-ministerial and central-local cooperative governance by reorganizing laws and regulations related to marine healing and establishing a cooperative system between ministries and regions. It is necessary to expand the function of the marine therapy R&D project to play a role as a marine therapy center for each coastal region.

• The Journal of Engineering Geology
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• v.10 no.3
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• pp.247-261
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• 2000

The geostatistical analyses for the chemical components of pH, TS, KMnO4 Demand, Cl, SO$_4$ and NO$_3$-N are carried out to understand the groundwater contamination in Pusan. The average values of each component are 7.2 for pH, 336.4mg/$\ell$ for TS, 2.3mg/$\ell$ for KMnO$_4$ Demand, 44.3mg/$\ell$ for Cl, 36.0mg/$\ell$ for SO$_4$, and 4.6mg/$\ell$ for NO$_3$-N. The ratios over the drinking standard of each component are 0.34% for pH, 2.27% for TS, 1.55% for KMnO$_4$ Demand, 1.59% for Cl, 0.57% for SO$_4$, and 3.7% for NO$_3$-N. The highest ratio of NO$_3$-N results from the municipal sewage and exhaust gas of vehicles. The isopleth maps of 6 chemical components show that the high values of groundwater contamination come from the inland of Pusan, and that some high values appear at the coastal area. The isopleth maps of Cl and SO$_4$ related with seawater intrusion also show that the high values appear only at the particular coastal area, not at the whole area. On the isopleth maps of Cl and SO$_4$, the anomalies of the concentration contours were compared with the directions of two large fault zones, the Ilkwang Fault and the Dongrae Fault. Apparently, they don't have the particular correlation. Therefore, it is concluded that the main source of groundwater contamination in Pusan is not the seawater, but the municipal sewage and other sources such as the exhaust gas of vehicles, the contaminated surface water, the waste water of factories, and the leachate of waste landfills.