• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.266-274
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• 1999

Vertical CTDT measurement at one point near tidewater glacier of fjord-head in Marian Cove, a tributary embayment of Maxwell Bay, South Shetland Islands was performed for 24 hours during the austral summer (January 21-22, 1998) to present water-column properties and SPM (suspended particulate matter) dispersal pattern in subpolar glaciomarine setting. Marian Cove shows three distinct water layers: 1) cold, freshened, and highly turbid surface plume in the upper 2 m, 2) warm, saline, and relatively clean Maxwell Bay water between 15-35 m in water depth, and 3) cold and turbid mid plume between 40-65 m in water depth. The surface plume is composed of silt-sized clastie particles mixed with flocculated biogenic detritus, and appears to originate from either supraglacial discharge by meltwater streams along the coast or water fall of ice cliff. Freshened and turbid mid plume consists exclusively of silt-sized clastic particles, resulting from subglacial discharge beneath the tidewater glacier. The disappearance of the two turbid plumes during the earlier period of measurement seems to be largely due to the breakup of the plumes by upwelling caused by strong easterly wind (> 8 m $sec^{-1}$). Thus, wind coupling over tidal effects regionally plays a major role in dispersal pattern of SPM as well as water exchange in Marian Cove.

• Journal of Aquaculture
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• v.19 no.1
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• pp.25-32
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• 2006

An experiment was carried out to investigate changing of water quality during the seed production of dark-banded rockfish Sebastes inermis in large scale tanks. Ten broodstock of dark-banded rockfish were held in three circular tanks (diameter 6.5 m; depth 2 m; water volume 50 ton) each (stocking density $0.061kg/m^3$). During the experiment the temperature ranged from 14.2 to $16.1^{\circ}C$. The fingerlings were 134 with rotifers only during 1 to 9 days after parturition, rotifers with Artemia nauplii during 10 to 20 days after parturition, Artemia nauplii only during 21 to 35 days after parturition, Artemia nauplii with commercial diet during 36 to 80 days after parturition and commercial diet only during 81 to 85 days after parturition. Water quality (dissolved oxygen, pH, $NH_4^+-N,\;NO_2^--N,\;NO_3^--N\;and\;PO_4^{3-}-P$) in rearing tanks measured every 5 days in long term monitoring investigation or every 2 hours in diurnal monitoring investigation. In 85 days after parturition, the body weight of fish grew up to 0.88 f and specific growth rate was 8.0%/day in body weight. In long term monitoring investigation, with the increase of the amount of supplied commercial diet, the concentration of dissolved oxygen (DO) and pH decreased, but the concentration of $NH_4^+-N\;(4.5\;to\;76.3{\mu}M),\;NO_2^--N\;(0.02\;to\;0.06{\mu}M),\;NO_3^--N\;(3.0\;to\;5.9{\mu}M)$, and $PO_4^{3-}-P\;(0.41\;to\;0.59{\mu}M)$ increased. In the diurnal monitoring investigation, the concentration of $NH_4^+-N$ showed great fluctuation and ranged from 3.0 to $9.1{\mu}M$ when fed rotifers, 16.3 to $45.8{\mu}M$ when fed Artemia nauplii and 36.5 to $120.1{\mu}M$ when fed commercial diet. After daily feeding with each of feed, the amount of dissolved inorganic nitrogen (DIN) and phosphorus (P) wastage were 7.0 g and 0.7 g when fed rotifers, 24.7 g and 0.7 g when fed Artemia nauplii and 140.9 g and 2.2 g when 134 commercial diet. The amount of DIN and phosphorous wastage during 134 commercial diet was significantly higher than that of fed rotifer and Artemia nauplii (P<0.05). Results will provide valuable information far water quality management and culture of dark-banded rockfish in commercial seed production systems.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.26 no.2
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• pp.141-149
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• 1993

The seasonal variation of lipid content was mostly attributed to diet, water temperature and period of reproduction etc. The lipid mainly consisted of neutral lipid and phospholipid. Nonpolar lipid content was higher in between late spring and summer, while polar lipid content lower during the period. The composition of neutral, glyco, and phospholipid of the total lipid: in average was 53.88, 10.09 and $36.03\%$, respectively. The neutral lipids were composed of triglycride($51.88\%$) and free sterol($23.21\%$) as major component and a little quantity of diglycerides, monoglycerides, esterified sterols and hydrocarbon, free fatty acid were also identified. The phospholipids of each fraction were mainly occupied by phosphatidyl choline($55.5\%$), followed by phosphatidyl ethanolamine($27.8\%$), phosphatidyl inositol($8.65\%$) and phosphatidyl serine($4.85\%$). The major fatty acids of the total lipid in ascidian were $C_{20:5},\;C_{22:6},\;C_{16:6}\;and\;C_{18:1}$, respectively. The fatty acid composition of phospholipid and neutral lipid showed a similar tendency to that of the total lipid. The major fatty acids in the fraction of glycolipid, however, appeared $C_{16:0},\;C_{20:1},\;C_{18:0}\;and\;C_{18:1}$ in order.

• Journal of Korea Soil Environment Society
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• v.2 no.2
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• pp.9-24
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• 1997

Surfactant-aided in situ soil flushing has been proposed as an alternative for the expensive and time consuming 'pump and treat' technology in remediation of contaminated soil and groundwater Injected surfactants can effectively solubilize contaminants sorbed to the soil matrix or nonaqueous phase liquids(NAPLs) in residual saturation. The contaminants solubilized in groundwater are recovered and treated further. The theoretical background of the technology and the results of the field operations, mostly in the US. were summarized. In addition, the factors crucial to the successful application of the technology were discussed. Cost analyses and technical limitations in current applications were also discussed. In conclusion, it is likely that in situ surfactant flushing become a viable option for soil remediation in limited cases. Currently, further advances with respect to operation cost and to treatment efficiency are required for more extensive application of the technology. However, the current trends in soil remediation, specially the growing emphasis on risk based corrective action and natural attenuation, will increase the competitiveness of the technology. For example, removal of easily washable contaminants by short term soil flushing followed by long term monitoring and natural attenuation can greatly reduce the operation cost and time.

• Journal of Aquaculture
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• v.4 no.1
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• pp.1-12
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• 1991

A series of rearing experiments were conducted to determine the growth rates and feed conversion efficiencies of tilapia in accordance with body size or age in nearly total closed system glass aquariums ($270\;\ell$ each in water volume) and concrete tanks ($4000\;\ell$) from April 10 to October 16, 1987. The fish used for the experiments was a Japanese strain of Oreochromis niloticus, and the size of the fish ranged from 7 g to more than 1,000 g in body weight. The starting stocking rates for each experimental lot were 10 to 20 kg in the glass aquarium ($3.7{\%}$ to $7.4{\%}$ of water volume) and 200 kg in the concrete tank ($5{\%}$ of water volume). A single experimental rearing term was 14 days with slight variations on occasions. Water temperature was designed to be kept at $26^{\circ}C$ but slight fluctuations were inevitable. Dissolved oxygen level was designed to be maintained at around $3\;mg/\ell$, but it also showed some variations. The ammonia level in the glass aquarium section once reached up to $18\;mg/\ell$, but generally remained at around $4\;mg/\ell$, and in the concrete tank section it was maintained at around $1\;mg/ell$. The feed was composed of mainly soybean meal with a small amount of fish meal as the protein source, and the crude protein content was about $32{\%}$. Mean daily growth rate was $3.5{\%}$ of body weight with 0.9 in food conversion ratio in the glass aquarium when the mean weight of fish was around 10 g with gradually reduced performances as the fish grew bigger. When the mean weight was 800 g, mean daily growth rate was $0.5{\%}$ with about 1.5 in food coversion for fish in the glass aquarium, and $0.8{\%}$ and 1.6 for fish in the concrete tank, respectively. According to the mean growth rate obtained from this experiment, it was calculated that the fish reared in the concrete tank require 223 days from 50 g to reach 1,000 g which is the ideal size for market in Korea, at the conditions provided as above, and 302 days from 10 g fingerlings to 800 g fish in the glass aquarium conditions of the closed recirculating water system.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.19 no.6
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• pp.563-574
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• 1986

The structure of gonads, gametogenesis and reproductive cycle of the jackknife clams, Solen strictus and Solen gordonis were investigated mainly by histological observation. The first species used were monthly sampled at the coastal area of Dadaepo, Pusan, Korea and Naechodo, Kunsan, Korea for one year from February 1982 to January 1983. The second species were monthly sampled at the sand beach of Dadaepo, Pusan, Korea, from February 1982 to January 1983. Sexualities of Solen strictus and Solen gordonis are dioecious, and these species are oviparous. The gonads are irregularly arranged from the subregion of mid-intestinal gland in visceral cavity to reticular connective tissue of foot. The ovary was composed of a number of small ovarian sacs and the testis was composed of several testicular lobuli which from the tubular structure. Early multiplicating oogonium was about $10{\mu}m$ in diamater. Nucleus and nucleolus, at that time, were distinct in appearance. Each of the early growing oocytes made an egg-stalk, connected to the germinal epithelium of the ovarian sac. A great number of undifferentiated mesenchymal tissue and eosinophilic granular cells are abundantly distributed in the ovarian sacs in the early development stages. With the further development of gonad, these tissue and cells gradually disappeared. Then the undifferentiated mesenchymal tissue and eosinophilic granular cells function as nutritive cells in the formation and development of the early stage germ cells. Mature oocytes were free in the lumen of ovarian sacs and gradually become round or oval. Ripe oocyte was about 80 to $90{\mu}m$ in diameter. With the further development of testis, each of the testicular lobuli formed stratified layers composed of spermatogonia, spermatocytes, spermatids and spermatozoa in groups on the germinal epithelium. After spawning, the gonad gradually degenerated, and disorganized completely. Then new differentiated tissues were rearranged next year. The annual reproductive cycle of those species could be classified into five stages; multiplicative, growing, mature, spent, degenerative and resting stage. It seems that the spawning season is closely related to the water temperature, and the spawning of Solen strictus occurs from June to July at above $20^{\circ}C$ in water temperature. The peak spawning season appeared in June at Dadaepo and in July at Kunsan, The spawning of Solen gordonis occurs from May to June with the peak spawning season in June. Percentages of the first maturity in female of Solen strictus ranging from 5.1-6.0 cm and 7.1-8.0 cm in shell length were $50\%$ and $100\%$, respectively.

• Korean Journal of Ichthyology
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• v.26 no.4
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• pp.310-321
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• 2014

Change in fish species composition after the Hebei Spirit oil spill in December 2007 off Taean were determined by analysis of samples collected in Mailpo beach, 10 km south from the oil spill site and polluted by the crude oil. Fish samples were collected by a beach seine in the shallow water at Malipo beach during the low tide of the new moon from February 2008 to December 2009. Five seine hauls were made during the day and the night in each sampling time. Monthly day and night samples did not show the significant differences in species composition. A total of 21 species, 1,032 individuals and 6,544 g of fish were collected in 2008, and 31 species, 4,206 individuals and 35,659 g of fish in 2009. The species collected were composed of the small-sized fish or juveniles. Abundant fishes were the resident species in coastal water, and the migrants were low in abundance. Among the fish occurred, Chelon haematochelius, Sebastes schlegelii, Takifugu niphobles and Pleuronectes yokohamae were predominated in abundance of both years. Monthly fish abundance and species diversity in 2008 were significantly lower than those in 2009. A few number of resident fish were collected from February to June 2008 showing the lowest in May 2008, and fish abundance increased from July 2008. The number of species and abundance of fish in 2009 were increased in spring as the temperature raised, showed a peak in summer and decreased in autumn. This monthly variation in fish species composition and abundance was similar to those in the non-polluted water in other temperate waters. Low fish abundance during several months after oil spill was considered to be related to the residual oil in the water and habitat disturbance due to oil cleaning activity in the beach. Monthly fish species compositions after September 2008 were similar to those of 2009 suggested that the impact on the shallow water fish by the oil residuals was not too significant at least to the fish species composition after September 2008.

• Journal of the Korean Society of Marine Environment & Safety
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• v.23 no.6
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• pp.669-676
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• 2017

To understand the relationship between environmental factors and phytoplankton community structures and why early outbreaks of Cochlodinium polykrikoides occur in the inner bay of Korea, short-term investigations were conducted at 17 stations in the eastern part of the South Sea of Korea, with sessions every two weeks from July 7 to August 24, 2016. The water temperature increased from $22.3^{\circ}C$ in the first survey to $28.4^{\circ}C$ in the fourth survey, which was a rise of about $6.01^{\circ}C$. Salinity was relatively high at Stns. 8 13 in the inner bay. In the first survey, rainfall of about 150 mm was observed, so nutrients were supplied at a high level and a high concentrate of Chl. a was observed. Cryptophyta (Crpytomonas spp.) represented 58.3 % of the community, followed by Bacillariophyta at 33.8 %. In particular, at Stn. 5, Dinophyta Prorocentrum spp. accounted for a very high percentage, 32.2 %. In the second survey, low phytoplankton populations were observed, and Bacillariophyta (Chaetoceros spp.) accounted for 61.0 %. At Stn. 4, Skeletonema spp. showed high populations but did not appear at other stations even at a low density. In the third and fourth surveys, phytoplankton populations were very low. Bacillariophyta represented 78.0 % in the third study and 73.3 % in the fourth. Interestingly, although the appearance of C. polykrikoides was investigated at the beginning of the red tide in the coastal area, they were not observed inshore, implying that the likelihood of inflow by the germination of resting cysts was low for the inner bay during this study period. In addition, environmental characteristics such as salinity and nutrient presence were significantly different between sampling stations due to the existence of a semi-closed bay in the southern sea, resulting in dominant phytoplankton species and community composition differing in these short-term investigations.

• Journal of Environmental Impact Assessment
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• v.27 no.6
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• pp.674-684
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• 2018

The purpose of this study is to construct ecological pond using LID technique in order to create naturally comfortable community space in urban idle space. The specification of the ecological pond is $110m^2$ of surface area, $0.45{\pm}0.02m$ of average depth, and bed material is composed of gravel (diameter ${\leq}60mm$), sand (diameter ${\leq}2mm$) and bentonite. Rainfall and water depth monitoring were conducted to determine the annual characteristics of inflow of the water for the ecological pond, result of total rainfall was 1,287 mm and showed a seasonal imbalance that accounted for 71.3% (918 mm) during July to August, but the annual mean water depth was kept constant at $0.45{\pm}0.02m$ due to the secondary water source. Annual trends of basic water quality showed a significant changes according to the season, such as water temperature ($5.2{\sim}28.8^{\circ}C$), DO (5.0 ~ 13.8 mg/L), EC ($113{\sim}265{\mu}S/cm$). BOD, COD, TN, and TP in physicochemical water quality tended to increase after October, but the ion parameters such as $NH_3$ and $PO_4{^{3-}}$ were generally low. Phytoplankton indicators Chl-a and BGA (blue green algae) showed a sharp increase from July to August, and green algae (Selenastrum bibraianum, Pediastrum boryanum etc.) and filamentous blue green algae (Phormidium sp.) emerged as a dominant species. The ion parameters ($F^-$, $Na^+$, $K^+$, $Mg^{2+}$, $Ca^{2+}$) were strongly correlated with the $Cl^-$ as a conservative substance (R=0.70~0.97, p<0.05). Water quality was influenced by the ambient environment such as seasonal changes or rainfall, and it was closely related to fluctuation of the inflow of the water. In the future, it is necessary to consider ecological connections by referring to the characteristics surveyed in this study in order to effectively manage the water quality and biodiversity of the ecological pond in idle space.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.591-600
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• 2018

The objective of this study was to determine the changes in phytoplankton and long-term water quality of Juksan-Weir in Yeongsan River that took place between April 2010 and December 2015. The number of species used in this study was 288, which consisted of 6% of Cyanophyta, 26% of Bacillariophyta, 53% of Chlorophyta and the others (15%). The standing crops of phytoplankton ranged from $500cells{\cdot}mL^{-1}-29,950cells{\cdot}mL^{-1}$ with an average of $7,885cells{\cdot}mL^{-1}$. At the two site, 20 dominant genera of found. The dominant genera were 6 of Bacillariophyta, 6 of Cyanophyta, 7 of Chlorophyta and 1 of Cryptophyta. The most dominant genus among the phytoplankton was Stephanodiscus sp. (Total 59%, each 54% and 63%). The most dominant genus among the Cyanophyta was Microcystis sp., which had a cell abundance ratio of 17%. The results of two sites were 21% and 13%, and the upstream was higher than the downstream.