• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.4
• /
• pp.938-945
• /
• 2004

On the relationship between the red tide occurrence and the oceanographic factors in the middle coastal area in the South Sea of Korea, the favorable oceanographic conditions for the red tide formation are considered as follows； the calm weather increases sea water temperature in summer and early-fall which the red tide occurs frequently, and the heavy precipitation brings some riverine water to ween: low salinity, high suspended solid, low phosphorus and high nitrogen, respectively. We decided the potential areas in the coastal zones vulnerable to the red tide occurrence based on the limited factors controlling the growth of phytoplankton. By using GIS through the overlap for three subject figures (phosphorus, nitrogen and suspended solids), it was founded that the potential areas are the Yeosu∼Dolsan coast, the Gamak bay, the Namhae coast, the Narodo coast, the Goheung and Deukryang bay. This result has very well coincided to the results of the satellite and in-situ data.

• Journal of Aquaculture
• /
• v.9 no.3
• /
• pp.239-245
• /
• 1996

As one of the red tide control method, montmorillonite was used to eliminate the causative organisms in Korea and Japan. We assayed the loess to replace the montmorillonite because it distribute in large quantity and nearby the red tide occurrence in South Coast of Korea. By using the mixture of loess and coal ashes, we examined the decreasing level of nutrients such as ammonia and phosphate, the elimination of causative organisms as a chlorophyll a content, and the harmful effect on aquaculture orgarnisms in cage culture farms. Half of the ammonium and phosphate was adsorbed by the loess particles, but only $25\%$ of ammonium was adsorbed by the coal ashes particles. In water column test, the particles of loess and coal ashes were settled down by $80\%$ in 20 minutes, the red tide organisms was eliminated by $80\%$ after 2 hours in 1,000 ppm of loess suspension, but the organisms were eliminated only $30\%$ by the same concentration of coal ashes. The harmful test of fishes and invertbrates, we observed any other negative effects of test animals than a tint deceleration in yellowtail.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.11 no.3
• /
• pp.113-123
• /
• 2008

We have analyzed a long term data of marine environments, red tide information and meteorology acquired by NFRDI and KMA, in order to understand the characteristics of marine environments in the Narodo coastal waters which is known to be the first outbreak region of Cochlodinium polykrikoides blooms. During the period of from 1992 to 2007, Cochlodinium polykrikoides blooms have first occurred more often in August. However, the outbreak time of the blooms tended to be earlier annually, and in addition, the surface salinity also had a tendency to increase. Consequently, it suggested that there might be a relationship between the transition of the outbreak time of the blooms and salinity. On the other hand, insolation was relatively rich but precipitation was relatively scarce in Gohung Province, compared to Yeosu or Tongyeong, when Cochlodinium polykrikoides blooms first occur in Narodo coastal waters. Average water temperature and salinity in August in Narodo coastal waters were all higher than those in Gamak and Jinhae bays, suggesting that Narodo coastal waters are a region of relatively high water temperature and high salinity. Also, concentrations of nutrients and chlorophyll- a were significantly low than those in Jinhae Bay, which is known to be a eutrophicated region, while the overall water quality seemed to be similar to Gamak Bay. The results of PCA(Principal Component Analysis) proved that insolation and water temperature are the most important factors for the outbreak of Cochlodinium polykrikoides blooms in Narodo coastal waters while concentrations of COD and dissolved oxygen are secondly important. Furthermore, typhoons also appeared to be one of most important factors for the outbreak of Cochlodinium polykrikoides blooms.

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.14 no.1
• /
• pp.19-31
• /
• 2011

This study has examined the water quality environment of six areas in the mid-southern coastal waters of Korea in order to find the significance between water quality and algal blooms of the area, based on the last 17 years of data offered by the National Fisheries Research and Development Institute. Water temperature in these areas fluctuated with a three to five year of period, and revealed little yearly variations at the surface layer while slowly decreasing at the bottom layer. On the other hand, salinity tended to increase both the surface and bottom layers. Algal blooms had a tendency to decrease in their outbreaks and causative species, with a peak of the middle of 1990s. C. polykrikoides prevailed in the entire areas, and in particular, almost annually appeared in Goheung coastal area since 1995. C. polykrikoides blooms occurred when a mean water temperature was approximately $26^{\circ}C$, and salinities were between 31.00 and 31.50 but exceptionally 28.68 in Yeosu Coast. However, the concentrations of DIN, DIP, TN, TP, including DO, turned out not to be such significant factors for the outbreaks of C. polykrikoides blooms. Therefore, water temperature was judged as the most controlling factor for the outbreak of C. polykrikoides blooms.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.20 no.4
• /
• pp.335-344
• /
• 2014

To understand the drift-diffusion of HAB(Harmful Algal Bloom) in this paper, we used three-dimensional hydrodynamic model POM(Pringceton Ocean Model) and Lagrangian particle track module. First, the results of residual flow that considered tide, wind, temperature, salinity, and TWC(Tsushima Warm Current) effect was tend to northeast in the coastal area and the flow in the offshore region showed results similar to TWC. To understand of HAB's movement, released each area that southern Kamak bay(Case 1), Mijo coast(Case 2), and southern Mireukdo coast(Case 3) assumption that red tide occurred. The areas where the HAB occurs frequently. As a result of HAB occurred in southern Kamak Bay(Case 1), mainly drifts to Narodo coast and Yeoja bay that located on the west side. Case 2 was mainly drifts to Yokjido coast and Saryangdo coast Especially, HAB occurred in Mireukdo coast(Case 3) relatively many particles drift to eastward as the influence of the TWC.

• Journal of Marine Life Science
• /
• v.7 no.2
• /
• pp.171-179
• /
• 2022

The present study investigated the survival rate, respiration rate, plasma stress index, and histological changes according to exposure time of cultured red seabream (Pagrus major) and olive flounder (Paralichthys olivaceus) exposed to Cochlodinium polykrikoides red tide. Fish cultured in natural seawater were used as the control group. Cochlodinium polykrikoides density was set to 5,500±200 cells·ml^-1 in the experimental groups. All red seabreams died within 1 hour of exposure to red tide, whereas all olive flounders died within 5 hours of exposure. Analysis of physiological response revealed that in red seabream, plasma glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), catalase (CAT), and glutathione peroxidase (GPx) concentrations were increased; plasma glucose and superoxide dismutase (SOD) concentration were decreased. Meanwhile, in olive flounders, plasma cortisol, GOT, and GPT concentrations were increased; plasma glucose concentrations were increased during the first hour of exposure, followed by decrease after 5 hours; and plasma SOD, CAT, and GPx concentrations decreased during the first hour of exposure. Histological analysis revealed structural damage to the gills of both red seabream and olive flounder. In conclusion, the exposure of red seabream and olive flounder to Cochlodinium polykrikoides red tide at the density of 5,500 cells·ml^-1 induces oxidative stress, which activates antioxidant defense mechanisms, ultimately leading to liver and gill damage.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.2 no.4
• /
• pp.179-190
• /
• 1998

All brick masonry buildings are constructed without any structural limitation under earthquake load, in Korea. However, it is necessary to evaluate response for seismic loads since the number of earthquake occurances in Korea is increasing. In this paper, the load resisting capacities of brick masonry buildings are investigated by finite element analysis method and the response due to seismic load are analyzed by applying 0.12g earthquake load. It was observed that the two story masonry building is not safe under the 0.12g earthquake load, especially at the first floor. The cracks were occurred under the bond beam and around the openings due to the stress concentration.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.21 no.1
• /
• pp.44-47
• /
• 2016

Real-time PCR was applied to early warning of red tide. For early warning of red tide at $10cells\;mL^{-1}$, Cochlodinium polykrikoides specific real-time PCR was used as a complement of microscopy that has a lower detection sensitivity. C. polykrikoides appeared extensively in Tongyeong, Namhae waters at low densities in the end of June, and early warning of C. polyrkrikoides blooms was issued on 2 August 2015.

• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.23 no.6
• /
• pp.468-474
• /
• 1990

Eight species, 6 Dinophyceae and 2 Raphidophyceae, caused a bloom in the southeastern coastal waters mainly in Chinhae Bay in Korea from March to September since 1982. Scrippsiella trochoidea and Heterocapsa triquetra bloomed in March then ensued a vernal species Heterosigma akashiwo. And Cochlodinium sp. and Alexandrium affine were occurred as causative organism in fall next to the estival dinoflagellates Gyrodinium instriatum and Pheopolykrikos hartmannii. Among them, spatio-temporal similarity of outbreak was significant in Heterosigma akashiwo since 1983, and a bit apparent for Cochlodinium sp.. The density was in the level from $10^3\;to\;10^5\;cells/ml$ and was dependent on the cell size rather than environmental characteristics.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.3 no.3 s.10
• /
• pp.173-181
• /
• 2003

Because of the gravitation of population toward large cities, a number of masonry buildings have been constructed since 1960's. They have been rapidly deteriorated as time passed by. Therefore the purpose of this paper is to present basic data on timeworn masonry buildings which were managed by the Jung, Mapo and Dobong district in Seoul Metropolitan and to analyse their deterioration factors as well as interrelation. Through this study, masonry buildings have many problems with foundation and crack is the most effective to deterioration. Also, the store buildings are the weakest structure type and the structure grade have an interrelation with occupancy type mere than any other factors.