• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.455-462
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• 2011

The accident in the Fukushima nuclear plant caused by the Great East Japan Earthquake on March 11, 2011 is raising voices concerning over radioactive contamination losses. In particular, radioactive contamination losses threaten the safe navigation of vessels, and may impair seafarers' safety and impede the healthy growth of world economy through marine transportation. In case vessels or cargos suffer radioactive contamination losses, it will take a high cost to remove the radioactive contaminants, and in worse cases the contaminated vessels or cargos may have to be abandoned. Furthermore, if seamen are exposed to radioactivity, their treatment can be raised as a crucial issue. Nevertheless, it has not been reviewed clearly by what method and on what ground such losses should be covered in case radioactive contamination losses take place. Thus, this study purposed to review coverage for radioactive contamination losses in marine insurance as an ex post preparation for damages caused by radioactive contamination.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.601-609
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• 2021

Erythrobacter species are extensively studied marine bacteria that produce various carotenoids. Due to their photoheterotrophic ability, it has been suggested that they play a crucial role in marine ecosystems. It is essential to identify the genome sequence and the genes of the species to predict their role in the marine ecosystem. In this study, we report the complete genome sequence of the marine bacterium Erythrobacter sp. 3-20A1M. The genome size was 3.1 Mbp and its GC content was 64.8%. In total, 2998 genetic features were annotated, of which 2882 were annotated as functional coding genes. Using the genetic information of Erythrobacter sp. 3-20A1M, we performed pan-genome analysis with other Erythrobacter species. This revealed highly conserved secondary metabolite biosynthesis-related COG functions across Erythrobacter species. Through subsequent secondary metabolite biosynthetic gene cluster prediction and KEGG analysis, the carotenoid biosynthetic pathway was proven conserved in all Erythrobacter species, except for the spheroidene and spirilloxanthin pathways, which are only found in photosynthetic Erythrobacter species. The presence of virulence genes, especially the plant-algae cell wall degrading genes, revealed that Erythrobacter sp. 3-20A1M is a potential marine plant-algae scavenger.

• Journal of Environmental Impact Assessment
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• v.9 no.4
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• pp.301-314
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• 2000

Marine surface sediments in the vicinity of Samcheonpo coal-fired power plant were analyzed by a total analysis($HF+HNO_3+HClO_4$) and sequential extraction procedure for heavy metals in order to investigate the total concentrations and geochemical phases of heavy metals. The result showed that the concentrations of Cr, Cu, Fe and Zn were within ranges typical for coastal areas, which reflected the mineralogical composition of the sediments in the studied area. However, the distributions of Cd, Co, Mn, Ni and Pb were rather different from the former, indicating that these heavy metals had a different origin, or that they were affected by a different geochemical mechanism. Chemical partitioning of heavy metals using sequential extraction procedure revealed that Cu, Fe, Pb, Zn were significantly bound to the residual phases of the sediments, whereas carbonate phases contained considerable amounts of Mn. The significant association of Pb with the exchangeable fraction also indicated that Pb was more mobile and bioavailable than Cu, Fe, Mn, Zn.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.20 no.5
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• pp.381-390
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• 1987

To evaluate the effects of the cooling water system on the primary production of marine phytoplankton, a series of experiments were made at the cooling water system of Samchonpo Power Plant from May 1985 to May 1986. Mechanical and physiological perturbations of the entrained process are the most detrimental to the primary production of marine phytoplankton. Nevertheless the primary production is increased by the heated water within the upper limit of temperature tolerence of the phytoplankton. The cooling water system, on the average, reduces the gross production and net production by 4.6 to 12.1 and 8.4 to $11.9\;mgC/m^3/h$, respectively.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2006.06a
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• pp.67-68
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• 2006

This study suggests a precision flow control system that enables fluid injection of a few grams at a time in a few ms time duration. The fluid injection system suggested here consists of a high pressure fluid pump, a 3 way 3 position directional control valve, an injector and an orifice. The orifice is located between the directional control valve and the injector. By supplying current signal to the directional control valve, the prescribed small amount of fluid can be supplied to a plant through the injector. The control robustness of the suggested system against the disturbances like the pressure change in a plant and the viscosity variation of the injected fluid is secured easily by using an orifice with very small inside diameter and setting the supply pressure with comparatively high value. The control performances of the suggested system are verified by numerical simulations and experiments. The outcomes of this research could be applied to the common rail injection control of lubrication oil for large size marine diesel engines, and other industrial plants.

• Journal of the Korean Society of Marine Environment & Safety
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• v.8 no.2
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• pp.39-44
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• 2002

In order to study the change of pollution loads flowing into Mokpo harbour after the operation of Mokpo Municipal Sewage Treatment Plant (MMSTP) and to evaluate the contribution of MMSTP operation to the improvement of marine water quality of Mokpo harbour, the pollution loads flowing into Mokpo harbour from land in dry weather were surveyed and estimated on the bases of the seasonal flow rates and the seasonal water qualities of streams and effluents located around Mokpo harbour from summer, 1997 to spring, 1998 before the operation of MMSTP, and the pollution loads of the inflow and the effluent of MMSTP were also surveyed and estimated from winter, 1998 to spring, 1999 after the operation of MMSTP. The treatment rates of MMSTP were shown to be about 49% in COD, 76% in TSS, 79% in VSS, 3% in T-N, 7% in DIP, 29% in T-P and -32% in DIN. The change rates of pollution loads flowing into the inner harbour of Mokpo due to the operation of MMSTP were shown to be about 56% In COD, 78% in TSS, 84% in VSS, 45% in DIN, 22% in T-N, 34% in T-P and -14% in DIP. The contribution rates of MMSTP operation to the reduction of total pollution loads flowing into the entire Mokpo harbour were found to be about 3% in COD, 3% in 755,5% in VSS,1% in DIP, 3% in T-P and -1% in DIN.

• Molecular & Cellular Toxicology
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• v.5 no.3
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• pp.265-271
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• 2009

Concentrations of industrial, agricultural and natural chemicals have been increasing in secondary effluents without their combined sub-lethal effects having been elucidated. In this study, two assays (the comet and acetylcholinesterase assays) were combined to evaluate the genotoxic and neurotoxic effects of effluent from the Noksan wastewater treatment plant (WWTP) on two local marine fish species (flounder and sea eel). The fish were exposed to WWTP secondary effluent that had been diluted with filtered seawater to final concentrations of 1%, 10% and 50%. Analysis of fish samples collected 3 and 5 days after exposure showed that DNA damage occurred in flounder exposed to 50% effluent and in sea eels exposed to 10% or 50% effluent. Furthermore, it was found that acetylcholinesterase (EC:3.1.1.7, AChE) activity decreased in both species when exposed to 10% effluent, indicating the presence of large amounts of genotoxic and neurotoxic chemicals in the effluent. Our results indicate that the comet and AChE assays are promising tools for biomonitoring of secondary effluents.

• Journal of Korean Society of Water and Wastewater
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• v.30 no.1
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• pp.9-17
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• 2016

Disinfectant/oxidation process is a crucial process in water treatment for supplying safe drinking water. Chlorination is still widely used for water treatment area due to its effectiveness on microbial inactivation and economic feasibility. Recently, disinfection concern in marine environment is increasing, for example, movement of hazardous marine organism due to ballast water, marine environmental degradation due to power plant cooling water discharge, and increase of the amount of disinfectant in the offshore plant. It is needed to conduct the assessment of disinfectant behavior and the development of disinfectant prediction model in seawater. The appropriate prediction model for disinfectant behavior is not yet provided. The objective of the study is to develop chlorine decay model in seawater. Various model types were applied to develop the seawater chlorine decay model, such as first order decay model, EPA model, and two-phase model. The model simulation indicated that chlorine decay in seawater is influenced by both organic and inorganic matter in seawater. While inorganic matter has a negative correlation with the chlorine decay, organic matter has a positive correlation with the chlorine decay.

• ALGAE
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• v.35 no.1
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• pp.79-89
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• 2020

Pythium species are ubiquitous organisms known to be pathogens to terrestrial plants and marine algae. While several Pythium species (hereafter, Pythium) are described as pathogens to marine red algae, little is known about the pathogenicity of Pythium on marine green algae. A strain of a Pythium was isolated from a taxonomically unresolved filamentous Ulva collected in an intertidal area of Oslo fjord. Its pathogenicity to a euryhaline Ulva intestinalis collected in the same area was subsequently tested under salinities of 0, 15, and 30 parts per thousand (ppt). The Pythium isolate readily infected U. intestinalis and decimated the filaments at 0 ppt. Mycelium survived on U. intestinalis filaments for at least 2 weeks at 15 and 30 ppt, but the infection did not progress. Sporulation was not observed in the infected algal filaments at any salinity. Conversely, Pythium sporulated on infected grass pieces at 0, 15, and 30 ppt. High salinity retarded sporulation, but did not prevent it. Our Pythium isolate produced filamentous non-inflated sporangia. The sexual stage was never observed and phylogenetic analysis using internal transcribed spacer suggest this isolate belongs to the clade B2. We conclude that the Pythium found in the Oslo fjord was a pathogen of U. intestinalis under low salinity.

• Journal of the Korean Magnetic Resonance Society
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• v.25 no.2
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• pp.24-32
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• 2021

Two new sesterterpenes, including a known sesterterpene, were isolated from the marine sponge Haliclona sp. collected in the Gageo island, Korea. One of the new sesterterpenes (1) was an unusual compound possessing a spiroketal moiety and the other (2) represented a four ring-fused skeleton. The planar structure of compound 1 was identical to gombaspiroketals A and B isolated from the marine sponge Clathria gombawuiensis, but the configuration for the two chiral centers was different each other. On the other hand, the skeletal structure of compound 2 was similar to that of phorone A isolated from Phorbas sp. and a compound from C. gombawuiensis, except for one configuration at C-8. However, in comparing the ¹H and ¹³C NMR spectral data, the proton and carbon chemical shifts for the three compounds were almost consistent. The NOESY spectrum revealed that the C-8 configuration of 2 was reversed to that of the two reported compounds. The configuration for compound 2 was supported by quantum mechanical calculation for the carbon chemical shifts and DP4+ probability for the protons and carbons of 2.