• Environmental Analysis Health and Toxicology
• /
• v.22 no.4
• /
• pp.321-327
• /
• 2007

4-nonylphenol (4-NP)이 해산어류인 조피볼락, Sebastes schlegeli의 혈장 vitellogenin (VTG), alkaline-labile protein phosphorus (ALPP), calcium(Ca), glutamate pyruvate transaminase (GPT) 및 hepatosomatic index (HSI)에 미치는 영향을 조사하였다. 실험어에 3일간격으로 $estradiol-17{\beta}$ ($E_2$, 5 mg/kg B.W.) 또는 4-NP(0, 10, 50, 100및 200 mg/kg B.W.)을 복강에 2번 주사한 후, 7일째에 채혈과 적출을 통해 혈장과 간장을 수집해 분석이 실시되었다. 대조 실험어에는 용매로 사용된 70% 에탄올만이 투여되었다. $E_2$ 투여 실험어의 혈장 단백질을 전기 영동상으로 분석한 결과 약 170 kDa의 위치에서 짙은 VTG 밴드가 관찰되었으나, 용매만 투여한 대조 실험어의 혈장에서는 동일 밴드가 관찰되지 않았다. 4-NP 투여한 모든 실험어의 혈장 단백질에서는 $E_2$ 투여 실험어와 동일한 VTG 밴드가 관찰되었다. 혈장 ALPP와 Ca 농도도 4-NP 투여 실험어에서 $E_2$ 투여 실험어와 유사하게 증가하였으며, 이들 농도 변화는 VTG 합성과 더불어 증가하는 경향을 나타냈다. 혈장 전위효소인 GPT와 HSI도 $E_2$ 투여 실험어와 유사하게 4-NP가 투여된 모든 실험어에서 급격히 증가하였다. 이상의 결과로부터 연안생태계 내에서 서식하는 어류가 4-NP과 같은 내분비 장애물질(Endocrine Disrupting compounds, EDCs)에 의해 영향을 받는지를 규명하기 위한 생물학적 지표로서 VTG와 더불어 혈장 ALPP와 Ca이 사용가능 할 것으로 판단된다. 또한, 조피볼락과 같은 해산어가 EDCs에 노출되어 VTG가 합성될 때 간장 기능의 손상으로 혈장 전위효소인 GPT가 일시적으로 종가하고 간장도 비대해져 HSI가 높아지는 것으로 판단된다.

• Geophysics and Geophysical Exploration
• /
• v.14 no.2
• /
• pp.127-132
• /
• 2011

We acquired and interpreted more than 650 km of high-resolution seismic reflection profiles in the Hupo Basin, offshore east coast of Korea at $37^{\circ}N$ in the East Sea (Japan Sea) to image shallow and basement deformation. The seismic profiles reveal that the main depocenter of the Hupo Basin in the study area is bounded by the large offset Hupo Fault on the east and an antithetic fault on the west; however, the antithetic fault is much smaller both in horizontal extension and in vertical displacement than the Hupo Fault. Sediment infill in the Hupo Basin consists of syn-rift (late Oligocene. early Miocene) and post-rift (middle Miocene.Holocene) units. The Hupo Fault and other faults newly defined in the Hupo Basin strike dominantly north and show a sense of normal displacement. Considering that the East Sea has been subjected to compression since the middle Miocene, we interpret that these normal faults were created during continental rifting in late Oligocene to early Miocene times. We suggest that the current ENE direction of maximum principal compressive stress observed in and around the Korean peninsula associated with the motion of the Amurian Plate induces the faults in the Hupo Basin to have reverse and right-lateral, strike-slip motion, when reactivated. A recent earthquake positioned on the Hupo Fault indicates that in the study area and possibly further in the eastern Korean margin, earthquakes would occur on the faults created during continental rifting in the Tertiary.

• Journal of Advanced Marine Engineering and Technology
• /
• v.40 no.4
• /
• pp.282-287
• /
• 2016

Recently in order to protect the ocean environment and to reduce energy consumption, shipbuilders have been developing highly economized ships. This research analyzed the possibility of adopting the onshore absorption refrigerator to offshore ships having a cooling system with refrigerant by using the waiste heat of the engine jacket cooling water instead of compression refrigerators. The results showed that R236fa could be a suitable medium for absorbing the heat of the absorber and condenser in an absorption refrigerator. The cooling system using R236fa achieved a high COP of 0.798, which is 15% and 5% higher than an air cooling system with a cooling tower and a water cooling system with a heat exchanger, respectively. The cooling system with R236fa achieved high efficiency with a 25% reduction in flow rate of LiBr solution and only 15.7% flow rate of cooling medium as compared to the water cooling system. The heating of sea water by the engine jacket water flowing out from the generator can prevent the crystallization of LiBr solution due to the low temperature of sea water.

• Korean Journal of Ecology and Environment
• /
• v.33 no.4 s.92
• /
• pp.358-365
• /
• 2000

To evaluate the influences of stocking and removal of silver carp on plankton communities and physicochemical parameters, fish biomanipulation was conducted in six enclosures constructed on the coast of a hypertrophic lake during the summer of 1997. Of these, three enclosures were established for the fish-stocking experiment; one fishless enclosure used as a control and two enclosures with high and low densities of fish. The other three enclosures for the fish-removal experiment were prepared in an entirely converse process compared to that for fish stocking. The results of randomized intervention analysis (${\alpha}=0.05$) showed significant changes in several physicochemical parameters and plankton communities after fish stocking and removal. Fish stocking decreased water transparency, DO, pH and chi-a (> $40\;{\mu}m$), while increasing the concentration of nitrogen and chi-a (<$2\;{\mu}m$). However, water transparency did not increase by fish removal. Small plankton communities, such as picocyanobacteria, eukaryotic picoplankton and ciliates (<$2\;{\mu}m$) showed significant reciprocal changes after both fish treatments: increase by the presence of fish and decrease by the absence of fish. No count of large sized phytoplankton and zooplankton showed significant change in the presence of fish, while large zooplankton, Diaphanosoma, Cyclopida and nauplii were significantly increased by fish removal. Although the frequent heavy-winds and endless supply of phosphorus from the lake sediment strongly disturbed the fish behavior and enclosure management, the stocking and removal of silver carp showed an obvious reciprocal influences on plankton communities and its physico-chemical parameters in a shallow-hypertrophic lake.

• Journal of the Korean Society of Fisheries and Ocean Technology
• /
• v.36 no.4
• /
• pp.314-321
• /
• 2000

In order to obtain the fundamental data on the auditory thresholds of fishes for catching method using low frequency sound, the auditory thresholds of coralfish Chromis notatus were measured in the presence of masking noise in the spectrum level range of 73~83dB re l$\mu$Pa/√Hz by heartbeat conditioning technique using pure tones coupled with a delayed electric shock. Critical ratios were about 23~41dB at measurement frequency, The critical ratio increased almost linearly with increasing frequency from 500Hz. The noise spectrum level at the start of masking was about 60~65dB. This suggests that hearing of coralfish is masked in the natural environment with the noise spectrum level above 60dB. The sound pressure level of which the signal sound of 300Hz is recognized by coralfish under the ambient noise is above 88dB and the critical ratio of them is above 23dB. The hearing index of coralfish with ambient noise was 81.

• Journal of Navigation and Port Research
• /
• v.30 no.8 s.114
• /
• pp.649-655
• /
• 2006

Waves progressing into the coastal area can be amplified, swashed and overtopped by a wave overtopping control structure, and it converts the kinetic energy of the waves to the potential energy with a hydraulic head above the mean sea level by conserving the overflow in a reservoir. Then the potential energy in the form of hydraulic head can be converted to electric power utilizing extremely low-head hydraulic turbine. This study aims to find the most optimal shape of wave overtopping structure which maximizes overtopping volume rate of sea water. Laboratory experiments for the performance evaluation of wave overtopping control structures were carried out in three dimensional wave tank, and the three dimensional structure models with planar wave concentration shapes(B/b) were manufactured into five classes, which were optimized by cross sectional parameters of the structure, ie, length of ramp(l), gradient of inclined ramp($cot{\phi}$) and freeboard height of the wave overtopping structure($h_e$) proposed by Shin and Hong(2005). The wave overtopping discharges were investigated with 20 incident wave conditions and wave directions of $0^{\circ},\;15^{\circ},\;30^{\circ}$.

• Journal of Fisheries and Marine Sciences Education
• /
• v.18 no.3
• /
• pp.293-301
• /
• 2006

This study was undertaken to prolonging the freshness in Squid(Todarodes pacificus) on the effects of ice storage methods(tap water ice, electrolytic water ice) using stainless diaphragm electrolytic instrument and also test an efficiency of instrument. Basically, stainless diaphragm electrolytic instrument studied for changes of pH on difference water flow and ampere. The lower water flower and higher ampere made low pH on acid part of electrolytic instrument. Squid samples were stored in tap water ice, acid part of electrolytic water and base part of electrolytic water and used in studying the changes of VBN and skin color through storage. Acid water had strong sterilization effects and VBN was lower levels of acid water than the others. Base water had not sterilization effects. Tap water ice storage was more sterilizing effects than base water ice storage but less effects than acid water ice storage. Lightness of Squid skin showed getting decrease at storage of ice water of all storage methods but acid water ice storage showed more retarding than the other two storage. From these results, it could be suggested that acid electric water ice storage is effective in extendance the shelf-life of squid at chilled storage.

• Journal of the Korean earth science society
• /
• v.35 no.2
• /
• pp.104-114
• /
• 2014

The variation of acidity, conductivity, and ion components in precipitation depending on the dominant wind direction was investigated from January, 2009 to December 2009 in Busan, Korea. Both southwesterly and northeasterly winds were dominant in Busan area. The volume-weighted mean acidity showed pH 7, and the high conductivity indicated 200 ${\mu}scm^{-1}$ in westerly wind. The volume-weighted mean equivalent concentration showed higher value of $K^+$ and $Cl^-$ in all wind directions. The composition ratio of $NO{_3}^-/SO{_4}^{2-}$ showed over 3 in northerly wind. The neutralization factors have been found to have higher value for potassium ion in northeasterly, easterly, southwesterly, and westerly winds compared with different wind directions, which indicated significant neutralization of acidic components over the region by potassium. Also, the concentration of sea salt has been found over 800 ${\mu}sm^{-3}$ in northeasterly and southwesterly winds. Air masses passing through Manchuria, Inner Mongolia plateau, China, and Russia in spring, autumn, and winter covered Busan, Korea in northerly, westerly, and northwesterly winds. However, air masses passing through the ocean in summer covered Busan, Korea in easterly, northeasterly, and southwesterly winds. Therefore, the variation of acidity, conductivity, and ionic components contained in precipitation shows each seasonal characteristics with prevailing wind systems between the continental and coastal area in Busan, Korea.

• Environmental and Resource Economics Review
• /
• v.30 no.1
• /
• pp.79-105
• /
• 2021

In the circumstance of standing out the climate change issue, the purpose of this study is to compare the efficiency of offshore and coastal fisheries according to whether or not greenhouse gas (GHG) emissions are considered, and then to present policy alternatives based on the analysis results. For analysis, the traditional data envelopment analysis (DEA), the slacks-based measure (SBM) and the SBM-undesirable models were used, and robust analysis of variance (ANOVA) and Wilcoxon Signed-rank tests were performed. As a result, the study showed that the average efficiency of fisheries decreased as the traditional DEA extended to the SBM model considering the slack and the SBM-undesirable model including the GHG emissions. Specifically, the average efficiency of the traditional DEA model, SBM model, and SBM-undesirable model was analyzed as 0.7350, 0.5820 and 0.4976 respectively. In addition, the results of the robust ANOVA and Wilcoxon Signed-rank tests all showed that there are statistically significant differences in efficiency between offshore and coastal fisheries as well as among traditional DEA, SBM and SBM-undesirable models. As a policy alternative to the analysis, it was suggested that to improve the efficiency of coastal and offshore fisheries, it is necessary to actively implement the new fishing vessel project and develop smart and electric hybrid fishing vessels.

• Korean Journal of Remote Sensing
• /
• v.38 no.6_1
• /
• pp.1541-1555
• /
• 2022

Red tide has potential to harm marine ecology and aquaculture. Research on detecting red tide using various optical remote sensors has been conducted, but most of existing algorithms for detecting red tide has limitations, especially in shallow coastal waters with high levels of suspended sediment. For enhanced understanding of the optical behavior of red tide waters, analysis on remote sensing reflectance and water constituent is becoming increasingly important. This study analyzed the optical remote sensing data and water quality variables(Chl-a_(Spec), SPM, a_ph, a_d, Turbidity, Chl-a_(HPLC), Dominant species) of red tide waters. The data were collected from ship-based campaigns. In addition to the research on detecting red tide, the remote sensing reflectance and extinction coefficients for mesodinium and cochlodinium species were also analyzed. Through the analysis, it was possible to estimate the red tide chlorophyll concentration based on a specific wavelength of the remote sensing reflectance. The study found that chlorophyll concentration and phytoplankton absorption coefficient were highly correlated(R²=0.9), and that the RE_diff formula provided a more accurate estimate of red tide concentration than the B-G ratio.