• Proceedings of the Korean Environmental Sciences Society Conference
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• 2003.05a
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• pp.85-87
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• 2003

문헌 32편에서 조사된 출현종수는 43종에서 200종까지였고, 그 중에서 주요종수는 2종에서 27종까지로 조사되었다. 본 조사에서 기록한 주요종은 모두 50속 116종이었고, 규조류 34속 89종(76.6%), 와편모조류 11속 22종(18.9%), 황갈색조류 2속 2종(1.7%), 남조류, 라피도조류, 유글레나조류가 각각 1속 1종(0.9%)이었다. 생태적 특성을 반영하는 주요종으로서는 우점종이 Actinoptychus serunius를 비롯하여 79종, 출현빈번종이 Coscinodiscus centralis를 비롯하여 50종, 적조원인종이 Cochlodinium polykrikoides를 비롯한 36종이었다. 또한 3가지의 주요 특성을 모두 지닌 종은 Prorocentrum micans를 비롯한 11종이었다. 여러 문헌에서 주요종으로 언급했던 종은 규조류인 Skeletonema costatum이었고 단일 속(genus)으로서 18종의 많은 종이 조사된 속은 Chaetoceros속이었다.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.469-472
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• 2006

The primary objective of this study was to gain insight into the characteristics of algal blooms in relation to the marine environment of the Korean Southern Coast, using more than 22 years worth of data since the first known occurrence of algal blooms. Algal blooms tend to occur when the precipitation or water temperature for a ten-day period prior to the annual bloom exceeds the long-term mean value. There are three notable causative species in six different inner bays, namely Prorocentrum sp., Skeletonema costatum, and Heterosigma akashiwo, and in addition, these three species appeared in different conditions of water temperature and salinity at each region.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.3
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• pp.154-163
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• 2005

Irregular discharges of freshwater through the water gates of the Keum River Estuarine Weir, Korea, whose construction had been completed in 1998 with its water gates being operated as late as August 1994, drastically modified the estuarine environment. Sharp decrease of salinity along with the altered concentrations of inorganic nutrients are accompanied with the irregular discharges of freshwater into the estuary under the influence of regular semi-diurnal tidal effect. Field sampling was carried out on the time of high tide at 2 fixed stations(St.1 near the Estuarine Weir and St.2 off Kunsan Ferry Station) every other day for 4 months from mid-February 2004 to investigate into the semi-weekly variation of spring phytoplankton community in relation to the freshwater discharges from Keum River Estuarine Weir. CV(coefficient of variation) of salinity measurements was roughly 2 times greater in St.1 than that in St.2, reflecting extreme salinity variation in St.1 Among inorganic nutrients, concentrations of N-nutrients($NO_3^-,\;NO_2^-$ and $NH_4^+$) were clearly higher in St.1, to imply the more drastic changes of the nutrient concentrations in St.1. than St.2 following the freshwater discharges. As a component of phytoplankton community, diatoms were among the top dominants in terms of species richness as well as biomass. Solitary centric diatom, Cyclotella meneghiniana, and chain-forming centric diatom, Skeletonema costatum, dominated over the phytoplankton community in order for S-6 weeks each (Succession Interval I and II), and the latter succeeded to the former from the time of <$10^{\circ}C$ of water temperature. Cyanobacterial species, Aphanizomenon Posaquae and Phormidium sp., which might be transported into the estuary along with the discharged freshwater, occupied high portion of total biomass during Succession Interval III(mid-April to late-May). During this period, freshwater species exclusively dominated over the phytoplankton community except the low concentrations of the co-occurring 2 estuarine diatoms, Cyclotella meneghiniana and Skeletonema costatum. During the 4th Succession Interval when the water temperature was over $18^{\circ}C$, the diatom, Guinardia delicatula, was predominant for a week with the highest dominance of $75\%$ in discrete samples. To summarize, during all the Succession Intervals other than Succession Interval III characterized by the extreme variation of salinity under cooler water temperature than $18^{\circ}C$, the diatoms were the most important dominants for species succession in spring. If the scale and frequency of the freshwater discharge could have been adjusted properly even during the Succession Interval III, the dominant species would quite possibly be replaced by other estuarine diatom species rather than the two freshwater cyanobacteria, Aphanizomenon flosaquae and Phormidium sp.. The scheme of field sampling every other day for the present study was concluded to be the minimal requirement in order to adequately explore the phytoplankton succession in such estuarine environment as in Keum River Estuary: which is stressed by the unpredictable and unavoidable discharges of freshwater under the regular semi-diurnal tide.

• KSBB Journal
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• v.25 no.6
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• pp.527-532
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• 2010

A thiazolidinedione derivative, TD49 with the highly selective algicide to red tide was newly synthesized and its acute toxicity was examined in order to evaluate the effect on aquatic ecosystems of coast. Major three species having important role in the food chain of marine ecosystem, such as Skeletonema costatum of microalgae, Daphnia magna of crustacea, Paralichthys olivaceus of flatfish fingerling were employed for the acute toxicity assessment. $EC_50$ or $LC_50$ as the assessment criterion was investigated to each specie, and NOEC (No Observed Effect Concentration) and PNEC (Predicted No Effect Concentration) from most sensitive specie to toxicity of TD49 were further calculated. $EC_50$ of S. costatum in 96-hour, $EC_50$ of D. magna in 48-hour, and $LC_50$ of P. olivaceus in 72-hour for TD49 were $0.34\;{\mu}M$, $0.68\;{\mu}M$, and $0.58\;{\mu}M$, respectively. NOEC from the results of S. costatum was estimated to be $0.20\;{\mu}M$ and PNEC was estimated as 3.40 nM by applying factor value of 100 to $EC_50$ $0.34\;{\mu}M$ of S. costatum. In addition, it was revealed that Solutol used as the dispersing agent of TD49 had very little toxic influence under the concentration range of $0{\sim}0.4\;{\mu}M$ used in TD49 toxicity experiment. Although the estimated concentration of TD49 that will be sprayed onto the coastal field for the algicide is higher than NOEC value, it is considered that the spraying concentration would not be a considerable problem due to a dilution effect by tide at the opened coast.

• Korean Journal of Environmental Biology
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• v.27 no.2
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• pp.205-215
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• 2009

In order to understand on the seasonal dynamics of phytoplankton in the mouth parts of Gamak Bay, Korea, we investigated from one station during June 2005 to June 2006. Samples were collected every week during the high water temperature (${\geq}20^{\circ}C$), and every two weeks during the low water temperature (${\leq}20^{\circ}C$). The phytoplankton community were composed of 76 genera, 208 species in the surface layer, and 72 genera, 186 species in the bottom layer (total: 77 genera, 214 species). The number of occurring species fluctuated greatly throughout the year from 27 species (March 15, 2006) to 121 species (Aug. 16, 2005). High number of species showed between June and September (>70 species), whereas the low number of species showed during the period of the low water temperature below $20^{\circ}C$ (ca. 40 species). The predominant species were diatom Skeletonema costatum during whole year, and two naked dinoflagellates, Cochlodinium polykrikoides and Polykrikos kofoidii during high temperature seasons. However, centric diatoms, Chaetoceros curvisetus, Chaetoceros debilis and Eucampia zodiacus were dominant species during low temperature seasons. Standing crops of dinoflagellate showed great fluctuations, which were ranged from $3.0{\times}10^5\;cells\;L^{-1}$ (April 17, 2006) to $7.3{\times}10^5\;cells\;L^{-1}$ (Aug. 2, 2005) in the surface layer and from $1.5{\times}10^3\;cells\;L^{-1}$ (Nov. 9, 2005) to $3.9{\times}10^5\;cells\;L^{-1}$ (Aug. 16, 2005) in the bottom layer, and showed high during high temperature seasons such as the number of species. The fluctuations were greater in the surface layer than in the bottom layer. Moreover, the variation of Cochlodinium polykrikoides, is affected by Polykrikos kofoidii grazing.

• Journal of the Korean Society for Marine Environment & Energy
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• v.15 no.4
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• pp.281-291
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• 2012

In this study, WET (whole effluent toxicity) test with Skeletonema costatum, Tigriopus japonicus and Paralichthys olivaceus and ERA (environmental risk assessment) were conducted to assess the unacceptable effect on marine ecosystem by emitting the treated discharge water from 'ARA Plasma BWTS' BWMS (ballast water management system) using filtration, Plasma and MPUV module. 34 psu treated discharge water from ARA Plasma BWTS shown slight chronic toxicity effect on the P. olivaceus ($7d-LC_{50}{\Rightarrow}100.00%$ treated discharge water, $7d-LC_{25}{\Rightarrow}85.15%$ treated discharge water). Bromobenzene, chlorobenzene and 4-chlorotoluene in 34 psu treated discharge water from ARA Plasma BWTS were higher than in the background original content of seawater. The PECs (predictive environmental concentrations) of bromobenzene, chlorobenzene and 4-chlorotoluene calculated by MAMPEC (marine antifoulant model to predict environmental concentrations) program (ver. 3.0) were 3.34E-03, 2.10E-03 and 1.73E-03 ${\mu}g\;L^{-1}$, respectively and PNECs (predicted no effect concentrations) of them were 1.6, 0.5 and 1.9 ${\mu}g\;L^{-1}$. The PEC/PNEC ratio of bromobenzene, chlorobenzene and 4-chlorotoluene did not exceed one and 3 substances did not consider as persistence, bioaccumulative and toxic. Therefore, it was suggested that treated discharge water from ARA Plasma BWTS did not pose unacceptable effect on marine ecosystem.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.1
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• pp.37-46
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• 2016

This study describes the spatio-temporal distributions in phytoplankton community such as species composition, standing crops and dominant species from April to November 2008 in the Uljin Marine Ranching Area (UMRA). A total of 123 species of phytoplankton belonging to 67 genera was identified. In particular, diatoms and dinoflagellates were occupied more than 60.5% and 34.6% of total species, respectively. The annual dominant species were Thalassiosira sp., Pseudo-nitzschia pungens in spring, Leptocylindrus danicus, Guinardia striata in early summer, Cheatoceros cirvisetus, Ch. decipiens in early autumn and Skeletonema costatum -ls (like species), Pn. pungens in autumn. Phytoplankton cell density fluctuated with an annual mean of $48cells{\cdot}mL^{-1}$ between the lowest value of $1.8cells{\cdot}mL^{-1}$ in early autumn and the highest value of $240cells{\cdot}mL^{-1}$ in spring. According to the cluster analysis, the phytoplankton community of the UMRA was characterized by the nutrient supply from land side and water movement as current.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.2
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• pp.93-102
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• 2001

Biomass and species composition of phytoplankton and zooplankton along the salinity gradients in the Seomjin River estuary were investigated in March, July, September and November, 1999. The locations of sampling sites were set based on the surface salinity during each cruise rather than geographic locations. A total of 96 phytoplankton species were identified with 60 diatom species in the study area. The species number of green algae was relatively high in low salinity region while the number of dinoflagellates increased in high salinity areas. Monthly mean of phytoplankton biomass ranged from 183 cells/ml to 833 cells/ml. There was a diatom bloom of Skeletonema costatum in November at the 5-15 psu salinity region and sharp decrease of biomass in very low salinity region occurred in March. During the rainy season in July with the salinity less than 8.1 psu, the green algae dominated in most of the study areas. Chroomonas spp. were highly dominant in March and September and the biomass increased towards the high salinity regions. A total of 83 zooplankton taxa were identified with 72 marine and 11 freshwater taxa. Major group of marine form was copepods with34 taxonomic groups. Most freshwater taxa were aquatic insects. Threshold salinities of freshwater zooplankton appearance were 8.1 psu in July, 4.7 psu in September, and 0.2 psu in November. The number of taxa appeared and abundances of zooplanktons were minimal in the middle of salinity gradients in this estuary.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.2
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• pp.219-226
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• 1995

A study was made of the concentration of the naturally occurring radionuclide $^{210}Po$ in seawater, plankton and fishes collected from Yongil Bay, Korea, in summer 1993. The mean value of the $^{210}Po$ concentration in sea water was determined to be about 1.9 mBq/l, with the proportion of the dissolved forms being about $46\%$. The mean $^{210}Po$ concentration factor in the centric diatom Skeletonema costatum, comprises > $95\%$ of the total phytoplankton cell number, was $7.6\times10^4$. Of five species of zooplankton examined, four species (two copepods and two mysids) had $^{210}Po$ concentrations in the range of $^{210}Po$ mBq/g dry weight. A copepod Labidocera bipinnata, however, was exceptional with a particularly high $^{210}Po$ level of 2,070 mBq/g. This indicates that L. bipinnata is primarily a raptorial feeder. The concentration of $^{210}Po$ in the pyloric caecum of pelagic fishes was 2,979-3,811 mBq/g, with the concentration factors of $3.4-4.3\times10^6$. The food chain concentration of $^{210}Po$ occurred as follows: phytoplankton < filter feeding copepods < omnivorous mysids < raptorial copepod < pelagic fishes.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.1
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• pp.441-453
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• 2017

This paper described the spatio-temporal distributions in the phytoplankton community, such as species composition, standing crops, and dominant species, from July 2012 to April 2013 in the Coastal Waters of Central South Sea (CWoCSS) of Korea. A total of 87 species of phytoplankton belonging to 52 genera were identified. In particular, diatoms and phytoflagellates comprised more than 62.1% and 37.9% of the total species, respectively. The phytoplankton cell density fluctuated with an annual mean of $7.9{\times}10^4cells{\cdot}L^{-1}$ between the lowest value of $1.0{\times}10^3cells{\cdot}L^{-1}$ in spring and the highest value of $4.5{\times}10^5cells{\cdot}L^{-1}$ in winter. The seasonal succession of the dominant species were Chaetoceros curvisetus, Ch. debilis in summer, Eucampia zodiacus in autumn, E. zodiacus, Thalassiosira curviseriata in winter and Skeletonema costatum -ls (like species), Leptocylindrus danicus in spring. According to principal component analysis, the phytoplankton community of the CWoCSS was characterized by the mixing rate between the freshwater inflow from Somjin River and the seawater of the South Sea, Korea.