• Korean Journal of Ichthyology
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• v.1 no.1_2
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• pp.9-18
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• 1989

Blenniid fish, Istiblennius stellifer(jordan et Snyder) is distributed in the coastal waters of south-eastern Korea and Japan. Matured adults of blenniid fish were collected from the rocky shore of Namchun-dong, Nam-gu, Pusan, Korea on May 15, 1988. The fertilized eggs were incubated and the larvae were reared in laboratory. The eggs of this species were demersal and adhesive, and their diameters varied from 0.84 to 0.88 mm(mean 0.86 mm, n=30). They have a number of small oil globules. The water temperature throughout incubation ranged from 18.5 to $23.3^{\circ}C$ and salinity was maintained at $28.2-29.5\;^{\circ}/_{\circ\circ}$. The hatching took place in 130 hours after fertilization. The newly hatched larvae were 2.70 mm in total length with 11 (abdominal)+22~25 (caudal)=33-36 myomeres. The larvae absorbed the yolk material and oil globule completely in 10 days after hatching and became postlarvae. Total lengths of the larvae reached 4.65 and 5.75 mm in 10 and 13 days after the hatching, respectively.

• Korean Journal of Ecology and Environment
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• v.39 no.1 s.115
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• pp.85-92
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• 2006

To evaluate the primary production and nutrient uptake of macrophytes in Lake Paldang, this study investigate the vegetation areas of six dominant aquatic plants including Typha angustifolia, Zizania latifolia, Phragmites australis, Trapa japonica, Nelumbo nucifera and Savinia natans, and contents of carbon, nitrogen and phosphorus of each macrophyte. Total vegetation area of six dominant aquatic plants was 1.37 $km^2$. Among them, Typha angustifolia was the most wide-distributed species which occupied the 46.7% of total vegetation area. Littoral zone of South Han river had the largest vegetation area with 0.458 $km^2$, and North Han river, Kyungan river and confluence area in the order named. The results of the contents of carbon, nitrogen and phosphorus of macrophytes showed that the carbon contents of emergent macrophytes was higher than that of other life-forms. The nitrogen content of Salvinia natans, free-floating macrophyte was highest and that of Typha angustifolia, emergent macrophyte was lowest. The phosphorus content of Trapa japonica showed the highest content of phosphorus among six macrophytes and emergent macrophytes such as Zizania latifolia and Phragmites australis showed lower contents of phosphorus than other life-forms. The annual net primary production of macrophytes in Lake Paldang, 2004, was calculated as 758.4 ton C $yr^{-1}$ and the annual net nitrogen and phosphorus uptake of macrophyte was 16,921 kg $yr^{-1}$ and 1,841.0 kg P $yr^{-1}$ respectively. Comparing the total budget of organic carbon, nitrogen and phosphorus in Lake Paldang, the amount of primary production and nutrient uptake by macrophytes take a small portion in total budget implying macrophytes do not play an important role in budget of matters in river-type lake, Lake Paldang.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.2
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• pp.118-126
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• 1986

Vibrio vulnificus is a recently recognized halophilic organism that nay cause serious human infections. Patients infected with V. vulnificus often have a history of exposure to the sea, suggesting that the organism may be common inhabitant of marine environment. The purpose of this experiment is to investigate the distribution and bacteriological characteristics of V. vulnificus. The strain used in this experiment was isolated from sea water and sea products such as common octopus (Octopus variabilis), ark shell (Anadara broughtonii), blue crab (Ericheir japonica), and sea squirt (Synthia roretzi) collected in Pusan area from July to October in 1985. V. vulnificus was frequently isolated in August when temperature of sea water was around $26^{\circ}C$ and rarely isolated in October when temperature of sea water was around $18.5^{\circ}C$. The distinctive biochemical characteristics of V. vulnificus were ONPG hydrolysis positive and fermented lactose and not grown in peptone water contained $8\%$ NaCl. The optical density at 660 nm of the growth of V. vulnificus was reached maximum level after 8 hours of culture at $35^{\circ}C$ in brain heart infusion broth but that of V. vulnificus was little increased at $15^{\circ}C$ for 14 hours. Optimum temperature and pH for the growth of V. vulnificus were around $35^{\circ}C$ and 8.0. The specific growth rate and the generation time of V. vulnificus isolated from the samples were $1.21\;hr^{-1}$, 34 min at $35^{\circ}C$ and $0.61\;hr^{-1}$, 69 min at $25^{\circ}C$, respectively. V. vulnificus did not grow on eosin-methylene-blue agar, salmonella-shigella agar, deoxycholate agar but grew well on Endo agar, xylose-lysine-deoxycholate agar and hektoen enteric agar. On Endo agar, the colonies of V. vulnificus were red and achieved a diameter of 2 to 4 mm as a feature enabling differentiation of V. vulnificus from other Vibrio spp. V. vulnificus grow well on TCBS agar forming green colonies. V. vulnificus refrigerated at $4^{\circ}C$ exhibited a linear decline of its viablity as 1 log cycle in every 16 hours storage, while V. vulnificus freezed at $-18^{\circ}C$ almost became extinct.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.1
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• pp.87-97
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• 1995

Acute and chronic toxicity of phenol on the mortality, long-term survival and respiration rates of the mysid, Archaeomysis kokuboi adult and juvenile were examined. This experiment was condurted by static bioassay procedure with the different salinity at $25^{\circ}C$ In lethal test, the test animals were exposed to 6 different phenol concentrations to determine $LC_{50}$ and I$LT_{50}$ (median lethal concentration and time) values. The $LC_{50}$ values with the exposure time for the mysid adult ranged from 31.31ppm to 1.49ppm phenol and for the mysid juvenile ranged from 6.90ppm to 0.26ppm in all experimental groups. Mortality was increased with the decrease of salinity, The $96hr-LC_{50}$ values at 16, 24 and $32\%o$ salinity for the mysid adult were 1.49, 2.71 and 4.53ppm phenol, white the values for the mysid juvenile were 0.26, 0.56 and 0.71ppm, respectively. The ratios of $96hr-LC_{50}$ values for the mysid adult to those for the mysid juvenile at 16, 24 and $32\%p$ salinity were 5.73, 4.84 and 6.38, respectively. The mysid juveniles were more sensitive to phenol than the mysid adults. Compared $LT_{50}$ values for the mysid adult with those for the mysid juvenile, the $LT_{50}$ values for the mysid adult ranged from 384.7 to 29.0 hours at 1.7-127ppm phenol concentrations and for the mysid juvenile ranged from 132.2 to 18.7 hours at 0.5~6.Oppm phenol concentrations. The lowest $LT_{50}$ values for the mysid adult and juvenile were showed at the combination of the highest experimental concentration of phenol and the lowest experimental salinity. The mysid juveniles showed lower $LT_{50}$ values than those of adults. The chronic effects of phenol on the mysid at the sublethal effective concentration of phenol were lower in the $32\%o$ salinitr group than 16 or $24\%o$ salinity groups. Oxygen consumption rates of the mysid adult were decreased with the increase of phenol concentration and exposure time, and decreased significantly in lower salinity at the same concentration or phenol.

• The Korean Journal of Petroleum Geology
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• v.12 no.1
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• pp.27-33
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• 2006

The possibility of oil reserve has been conformed because the oil has been produced by 450 barrel per day in the West Korea Bay basin of the North Korea. There is also possibility of giant oil reserve since it is geographically close to one of the biggest oil fields of Bohai Basin, China. Based on the on-going oil exploration and the present condition of investment, the areas of ongoing oil exploration are three: West Korea Bay B&C prospect explored by Swedish Taurus, the north of West Korea Bay and Anju basin explored by Canadian SOCO, and East Korea Bay explored by Australian Beach Petroleum. However, there is little or no possibility of oil reserve in the rest sea areas of three. Even though oil reserves were discovered in the some parts of land areas such as Kilju and Myungcheon, it was presumed to have no economical efficiency. Geology in West Korea Bay off the North Korea is similar to that in Bohai Bay off China. The basement consists of thick carbonate rock of the Late Proterozoic and Early Paleozoic overlain by Mesozoic ($6,000{\sim}10,000\;m$) and Cenozoic ($4,000{\sim}5,000\;m$) units. Source rocks are Jurassic black shale (3,000 m or more), Cretaceous black shale ($1,000{\sim}2,000\;m$), and pre-Mesozoic carbonates (several thousand meters). Reservoir rocks are Mesozoic-Cenozoic sandstone with high porosity and pre-Mesozoic fractured carbonate rocks. Petroleum raps are of the anticline, fault sealed, buried hill, and stratigraphic types. It absolutely needs to take up a positive attitude, the activation of ocean science and technology exchange, and the joint research and development of modern MT (Marine Technology) considering the state of establishing new international ocean order forcing on building up 200 nautical mile EEZ (exclusive economic zone) among coastal nations. Both South and North Koreas should extend the ocean jurisdiction and contiguity, and MT development dealing with the same sea areas. It is more urgent problem to find a way to have the North Korea participated in, and then to develop ocean management and ocean industry individually.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.5 no.3
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• pp.208-215
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• 2000

The estimated total material transports through the Cheju Strait using all data which investigated in 1997 and 1999 are as follows; A large amount of suspended sediments and dissovted inorganic nutrients are carried tothe South Sea through the Cheju Strait by a persistent eastward flow (Cheju Current) from the Y311ow Sea andthe East China Sea. The annual material Oanspous by the Cheju Current are as follows; 22.9${\times}$10$^6$ ton yr$^{-1}$(SS), 0.52${\times}$10$^{10}$ mol yr$^{-1}$ (NH$_4\;^+$), 6.05${\times}$10$^{10}$ mol yr$^{-1}$ (NO$_3\;^-$), 0.36${\times}$10$^{10}$ mol yr$^{-1}$ (PO$_4\;^{3-}$), 10.27${\times}$10$^{10}$ mol yr$^{-1}$ (Si(OH)$_4$). The annual suspended sediment flux per water transport in the Cheju Strait (44.48${\times}$10$^6$ ton yr$^{-1}$ Sv$^{-1}$) is about 1.7 larger than that in the Korean Strait (26.08${\times}$10$^6$ ton yr$^{-1}$ Sv$^{-1}$). The annual nitrate flux per water transport (11.60${\times}$10$^{10}$ mol yr$^{-1}$ Sv$^{-1}$) is about 1.2 larger than that in the Korean Strait (9.72${\times}$10$^{10}$ mol yr$^{-1}$ Sv$^{-1}$) and 2/3 of that by Kuroshio in the East China Sea (18.55${\times}$10$^{10}$ ton yr$^{-1}$ Sv$^{-1}$). It suggests that chemical rich Cheju Current will play a significant role in the biogeochemical processes in the South Sea where the huge land-based waste are introduced.

• Economic and Environmental Geology
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• v.45 no.6
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• pp.685-695
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• 2012

We studied the detailed bathymetry and the geophysical characteristics of the summit of the Dokdo volcano using mutibeam echosounding and geophysical survey data. The bathymetry around the main east and west islets of the Dokdo volcano shows very shallow within about 10 m water depth. From near islets to about 30 m b.s.l., the shallow water area has very steep slope and many irregular sunken rocks. The area from about 30 m to about 80 m b.s.l. shows gentle rises and falls, and less steep slope. The area from 80 m b.s.l. has gradually flat undulation and smooth slope seabaed and is extended to offshore. The main islets of the Dokdo volcano and the rocky sea bottom elongated from the islets might be the residual part of the eroded and collapsed main crater of the Dokdo volcano. The bathymetry and the seafloor image(from backscattering) data show small craters, assumed to be formed by the eruption of later volcanism. The seafloor images propose that, except some areas with shallow sand sedimentary deposits, there are typical rocky bottom such as rocky protrusions and lack of sediments in the main morphology of the survey area. The stepped slopes of the seabed are deduced to be submarine terraces. The several prominent submarine terraces are found at the summit of the Dokdo volcano, suggesting repetition of sea level changes(transgressions and regressions) in the Quaternary. The results of the magnetic anomaly and the analytic signal have a good coherence with other geophysical consequences regarding to the location of the residual crater.

• Korean Journal of Environmental Biology
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• v.36 no.1
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• pp.43-49
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• 2018

The toxic assessment of the PBDEs (BDE-47, BDE-209) has been comprehensively investigated by using the rates of survival and population growth in the marine rotifer, Brachionus plicatilis. Chiefly, the survival rate was determined after a measurement of 24 hours of exposure to the BDE-47 (2,2'4,4'-Tetrabromodiphenyl ether) and the BDE-209 (2,2',4,4'-Decabromodiphenyl ether) was performed. The BDE-47 reduced survival rate in dose-dependent manner and a significant reduction were noted to have occurred at a concentration of greater than $3.9mg\;L^{-1}$, but the BDE-209 had no effect which was subsequently observed in this study. The population growth rate (r) was determined after 72 hours of exposure to toxicants in the study. It was observed that the r value in the controls (absence PBDEs) was greater than 0.5, and that it decreased as the dose-dependent manner as recorded. The survival rate when exposed to BDE-47 and BDE-209, $EC_{50}$ value was $13mg\;L^{-1}$ and $>1,000mg\;L^{-1}$, and population growth rate was $3.67mg\;L^{-1}$ and $862.75mg\;L^{-1}$, respectively. Therefore, the BDE-47 is considered to be 76-235 times more harmful than the BDE-209 as noted. In this study, the ecotoxicological bioassay using a noted survival rate and population growth rate of B. plicatilis can be used as a baseline data for the continued establishment of the environmental quality standard of the incidences of the BDE-47 and BDE-209 in a marine environment.

• Korean Journal of Environmental Biology
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• v.37 no.3
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• pp.372-379
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• 2019

We evaluated the toxic effects of phenanthrene (PHE) and zinc undecylenate (ZU) on the population growth rate (r) of the marine diatom, Skeletonema costatum. The r of S. costatum was determined after 96 hrs of exposure to PHE (0, 25, 50, 100, 200 and 300 mg L^-1) and ZU (0, 5, 10, 15, 20 and 25 mg L^-1). The results showed that r in the control (the absence of PHE and ZU) was greater than 0.04, while r in the treatment groups decreased with increasing PHE and ZU concentrations. PHE and ZU were shown to reduce r in a dose-dependent manner, with significant decreases occurring at concentrations above 50 and 10 mg L^-1, respectively. The EC₅₀ values of r in PHE and ZU exposure were 136.13 and 16.95 mg L^-1, respectively. The no observed effect concentrations (NOEC) were 25 and 5 mg L^-1, and the lowest observed effect concentrations (LOEC) were 50 and 10 mg L^-1. These results indicated that concentrations of greater than 50 mg L^-1 of PHE and 10 mg L^-1 of ZU in marine ecosystems induced a toxic effect on the r of S. costatum. These results can serve as useful baseline data for the establishment of safety concentrations of PHE and ZU in marine ecosystems.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.4
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• pp.199-213
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• 2008

Saemangeum salt-water Lake has been created by the completion of the sea-dike in April 2006. To monitor the water qualities of the lake during the sea-dike construction, salinity, SS, nutrients(DIN, DIP, DISi), and chlorophyll-$\alpha$ was analyzed for the surface water from 1999 to 2007. Due to the dike construction, weaker tidal current and lesser resuspension of bottom sediment resulted in the marked decrease of the concentrations of SS in the lake water. Consequently the clearer lake water has provided better condition for primary production with deeper penetration of sunlight into the water column and sufficient nutrient content in the water. Finally the chlorophyll-$\alpha$ content became approximately double in the concentration after the dike construction. Highly stimulated algal production with the marked decrease of the concentrations of SS was decreased the concentration of DIP in the surface water. On the other hand the concentration of DIN and DISi in surface water was increased after dike construction due to the expansion of the freshwater and the supply from bottom layer. As a result, the lake revealed an extremely high NIP ratio and a DIP-limited ecosystem. The lake has been transformed from a typical coastal ecosystem to a brackish one. Since the dike completion, the lake has shown a similar change pattern to the Geum River estuary. Due to the salt-wedge intrusion of seawater, it is highly probable to expect the formation of low-oxygen zone at the bottom layer near the river-mouth area of the lake during the summer. Therefore we need a continuous sentinel monitoring of bottom water qualities in the near future.