• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.3
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• pp.134-139
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• 2005

The purpose of this study is to quantify the penetration behavior of spilled weathered oil and dispersed oil and to evaluate the influence of the penetrated oils on seawater infiltration in tidal flat environment. The penetration depths of the spilled oils into the tidal flat sediments were gradually deeper according to increase the stranded oil volume. The penetration depth of stranded oil were abruptly dropped at first falling tide, but were not significantly fluctuated after that. Moreover, hydrocarbon concentration was most high within the upper 2 cm. Seawater infiltration was decreased in proportion to the stranded oil volume. Dispersed oil was easily permitted the seawater infiltration than weathered oil and crude oil. Therefore, quick cleaning actions fur penetrated oil will be required far recovery of seawater infiltration, because the seawater contains oxygen and nutrients required for the survival of benthic organisms in tidal flat.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.5
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• pp.411-422
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• 1986

Diets of the rock trout, Agrammus agrammus, in the shore area of Tongbaeksom, Pusan over the period of July 1981 to June 1982 were studied. Specimens were sampled by angling. Stomach analysis showed that the rock trout fed mainly on epibenthic food in the littoral zone along the coast of Tongbaeksom. The food organisms of the enviornment were studied by means of underwater sampling around the angling area for this study. Although the food items of the fish changed slightly with season and age-group, main food items were Amphipoda (Gammaridae, Caprellidae) and Isopoda (Sphaeromidae, Idotheidae). This suggests that the diets of A. agrammus mainly comprised epibenthic food. Food diversity increased with age. The fish almost consummed on smaller food in size, but had selective predation according to food size, i. e. on larger food as age increases. These data provide additional support for the importance of the detritus-benthos-consummer type food chain.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.3
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• pp.219-226
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• 2012

The International Maritime Organization (IMO) adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments in 2004 to prevent the transfer of aquatic organisms via ballast water. Thirty-four ballast water treatment systems were granted IMO active substance basic approval, among which twenty systems were granted final approval. This paper is an in-depth consideration of the mechanism principles of the treatment systems that received active substance basic or final approval from IMO, and on the concentration of Total Residual Oxidant (TRO). The TRO maximum allowable discharge concentration was reduced by neutralization equipment, resulting with a concentration lower than 0.2 ppm. However, between various treatment systems TRO maximum allowable dosage showed large differences, ranging from 1 to 15 ppm. The discrepancies of treatment allowable dosage concentration between different treatment systems are largely due to the properties of species and water conditions such as the temperature and turbidity, rather than the characteristics of treatment systems and the type or presence of filters etc.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.225-229
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• 2003

Plant ash and soil drainage, derived by frequent mountain fires during winter, might cause biological contamination to seaweeds at seashore and river mouse area. To thalli of Ulva pertusa, maximum non-lethal concentration(MNLC), lethal concentration 50 $(LC_{50})$ and minimum lethal concentration (MLC) of pine needle ash were shown as 60, 350 and 550 mg/mL, respectively. The yellow loess and granite sand did not damage at concentrations of 20 and 200 mg/mL, respectively To thalli of Porphyra yezoensis, the MNLC, LC5O, MLC of pine needle ash were shown as 0.08, 0.4 and 1.0 mg/mL, respectively. Effects of yellow loess and granite sand were approximately 1/2 and 1/10 of the ash. To thalli of Undaria pinnatifida, the pine needle ash, yellow loess and granite sand did not damage at the concentration range of 20 to 40 mg/mL. Change of pigments $(chlorophyll\;\alpha,\;lutein,\;\beta-carotene,\;phycoerthrin)$ was also determined at the MNLC, $LC-{50}$ and MLC of pine needle ash. Among three seaweeds tested, P. yezoensis produced the most 2.7-fold of lutein and 2.3-fold of $\beta-carotene$ at $LC-{50}$ of the ash. Thus the P. yezoensis, appeared as a sensitive indicator, could be used as one of test organisms for determination of the biological effect of pollutants contaminated in marine environment.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.6
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• pp.139-147
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• 2014

The ballast water may be discharged into another sea area with marine organisms, it caused problems to disturb the marine ecosystem. So, in order to remove these environmental risk factors, the IMO has mandated the installation of BWTS to the all ships. Our monitoring system diagnose and predict a failure of BWTS by analyzing the sensor information of BWTS collected from which the ships scattered in the ocean of several. This paper presents the design and implementation of communication modules for BWTS remote monitoring considering the satellite communication charge fee. In the our study, we implemented the safety and cost-saving communication modules by LabVIEW program. The collected sensor informations is encrypted and compressed by LabVIEW modules running on RIO. Then they will be transfer to the land server and will be decrypt to enable monitoring in the land server. For the verification, we build the test modules which can verify from collecting the sensor data to consuming them in the monitoring server. We carried out 20 times for the data pattern in all of case. So, we verified the excellent functionality and reliability through the experimental result.

• ALGAE
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• v.31 no.4
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• pp.373-378
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• 2016

Cochlodinium polykrikoides is a red-tide forming dinoflagellate that causes significant worldwide impacts on aquaculture industries and the marine ecosystem. There have been extensive studies on managing and preventing C. polykrikoides blooms, but it has been difficult to identify an effective method to control the bloom development. There is also limited genome information on the molecular mechanisms involved in its various ecophysiology and metabolism processes. Thus, comprehensive genome information is required to better understand harmful algal blooms caused by C. polykrikoides. We estimated the C. polykrikoides genome size using flow cytometry, with detection of the fluorescence of DNA stained with propidium iodide (PI). The nuclear genome size of C. polykrikoides was 100.97 Gb, as calculated by comparing its mean fluorescence intensity (MFI) to the MFI of Mus musculus, which is 2.8 Gb. The exceptionally large genome size of C. polykrikoides might indicate its complex physiological and metabolic characteristics. Our optimized protocol for estimating the nuclear genome size of a dinoflagellate using flow cytometry with PI can be applied in studies of other marine organisms.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.1
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• pp.1-13
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• 2016

Physiological response of fish and bivalve was estimated to identify the physiological changes of test species by lowering water temperature due to the abrupt stop of cooling water discharge from power plant. The experiment was conducted by two conditions; fall and winter by decreasing water temperature ($2^{\circ}C$/2 days) from $26^{\circ}C$ to $17^{\circ}C$ for fall scenario and from $15^{\circ}C$ to $9^{\circ}C$ for winter scenario, respectively. Test organisms were parrot fish (Oplegnathus fasciantus) and bivalve (Gomphina melanaegis), and end points were mortality for both species, hematocrit and cortisol for fish, and hemolymph and superoxide dismutase(SOD) for bivalve. 48/96hr mortality test revealed no mortality for fish and 47% mortality for bivalve at 96hr/$26^{\circ}C$ only. Significant increases of hematocrit and cortisol were found at fishes exposed to $26^{\circ}C$ (high temperature) and lower temperature ($9{\sim}13^{\circ}C$), respectively. Hemolymph and SOD for bivalve tended to decrease by lowering water temperature from 15 to $9^{\circ}C$ (winter scenario) and no changes from 26 to $17^{\circ}C$ (fall scenario). Fall scenario (from 15 to $9^{\circ}C$) showed more significant changes of physiological response than winter cases (26 to $17^{\circ}C$).

• Proceedings of the Korean Environmental Sciences Society Conference
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• 2006.11a
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• pp.285-289
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• 2006

In screening of algicidal bacteria, we isolated a marine bacterium which had potent algicidal effects on harmful algal bloom (HAB) species. This organism was identified as a strain very close to Bacillus subtilisby 16S rRNA gene sequencing. This bacterium, Bacillus sp. SY-1, produces very active algicidal compounds against the harmful dinoflagellate Cochlodinium polykrikoides. We isolated three algicidal compounds (MS 1056, 1070, 1084) and identified them by amino acid analyses, fast atom bombardment mass spectrometry (FAB-MS), infrared spectroscopy (IR), $^1H$, $^{13}C$, and extensive two-dimensional nuclear magnetic resonance (2D NMR) techniques including $^1H-^{15}N$ HMBC analysis. One of them, MS 1056, contains a b-amino acid residue with an alkyl side chain of $C_{15}$. MS 1056, 1070, and 1084 showed algicidal activities against C. polykrikoides with an $LC_{50}$ (6 hrs) of 2.3, 0.8, $0.6\;{\mu}g/ml$, respectively. These compounds also showed significant algicidal activities against other harmful dinoflagellates and raphidophytes. In contrast, MS 1084 showed no significant growth inhibition against various organisms coexisting with HAB species in natural environments, including bacteria, eukaryotic microalgae, and cyanobacteria, although it inhibited growth of some fungi and yeasts. These observations imply that algicidal bacterium Bacillus sp. SY-1 and its algicidal compounds could play an important role in regulating the onset and development of HABs in the natural environments.

• ALGAE
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• v.31 no.3
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• pp.243-256
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• 2016

Concerns about how ocean acidification will impact marine organisms have steadily increased in recent years, but there is a lack of knowledge on the responses of macroalgae. Here, we adopt an outdoor continuous-flowing mesocosm system designed for ocean acidification experiment that allows high CO₂ conditions to vary with natural fluctuations in the environment. Following the establishment of the mesocosm, five species of macroalgae that are common along the coast of Korea (namely Ulva pertusa, Codium fragile, Sargassum thunbergii, S. horneri, and Prionitis cornea) were exposed to three different CO₂ concentrations: ambient (×1) and elevated CO₂ (2× and 4× ambient), over two-week period, and their ecophysiological traits were measured. Results indicated that both photosynthesis and growth exhibited species-specific responses to the different CO₂ concentrations. Most notably, photosynthesis and growth increased in S. thunbergii when exposed to elevated CO₂ conditions but decreased in P. cornea. The preference for different inorganic carbon species (CO₂ and HCO₃⁻), which were estimated by gross photosynthesis in the presence and absence of the external carbonic anhydrase (eCA) inhibitor acetazolamide, were also found to vary among species and CO₂ treatments. Specifically, the two Sargassum species exhibited decreased eCA inhibition of photosynthesis with increased growth when exposed to high CO₂ conditions. In contrast, growth of U. pertusa and C. fragile were not notably affected by increased CO₂. Together, these results suggest that the five species of macroalgae may respond differently to changes in ocean acidity, with species-specific responses based on their differentiated photosynthetic acclimation. Understanding these physiological changes might allow us to better predict future changes in macroalgal communities in a more acidic ocean.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.53 no.4
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• pp.506-514
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• 2020

We investigated seed management and feeding regime of larval red spotted grouper Epinephelus akaara using live food organisms. Fertilized eggs were produced in March 2020 by manipulating photoperiod and water temperature. Broodstock (F0) produced approximately 0.30×10⁶ eggs, of which 0.25×10⁶ were fertilized; first-generation broodstock (F1) produced 2.00×10⁶ eggs, of which 1.90×10⁶ were fertilized. Larvae were reared at temperatures of 21.0-24.5℃. The feeding regime consisted of rotifers Artemia, and commercial pellet feed. From 5-8 days after hatching (dah), rotifers collected from high-density incubation tanks were fed to grouper larvae at a density of 10-20 individuals/mL. From 9-30 dah, rotifers collected from low-density incubation tanks were fed to larvae at a density of 10-20 individuals/mL. Newly hatched Artemia were provided from 20-24 dah and enriched Artemia from 25-50 dah. Commercial pellet feed was given starting at 13 dah. The average mouth size in hatchlings was 263.4±3.7 ㎛ at 5 dah, 406.7±21.0 ㎛ at 11 dah, and 856.9±136.6 ㎛ at 21 dah. At 1 dah, larvae had a mean total length of 1.95±0.06 mm. At 66 dah, the mean TL was 4.0 cm. The final number of surviving red spotted grouper larvae was 218,380 fishes.