• Korean Journal of Environmental Biology
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• v.34 no.4
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• pp.292-303
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• 2016

This study described the spatial distributions of marine environmental factors such as water temperature, salinity, chlorophyll a concentration and turbidity, and characteristics of phytoplankton community such as species composition, standing crops and dominant species at 19 fishing ports around Jeju Island during the early summer of 2016. I analyzed bio-oceanographical characteristics using principal component analysis (PCA) of the environmental factors and biological parameters. Water temperature, salinity, chlorophyll a and turbidity ranged from 17.6 to $20.7^{\circ}C$, from 26.19 to 32.33 psu, from 0.76 to $7.13{\mu}g\;L^{-1}$, and from 0.51 to 14.49 FTU, respectively. A total of 51 species of phytoplankton belonging to 35 genera were identified. In particular, diatoms and dinoflagellates accounted for more than 56.8% and 27.4% of all the species, respectively. Moreover, the number of phytoplankton species was controlled by salinity. Phytoplankton cell density ranged from $2.9cells\;mL^{-1}$ to $185.9cells\;mL^{-1}$. The dominant species were Navicula spp. Stephanopyxis turris, Eutreptiella gymnastica and Mesodinium rubrum. Environmental factors and the phytoplankton community varied greatly between sampling sites. According to PCA, the biological oceanographic characteristics of the around Jeju Island were characterized by meteorological factors such as air temperature, precipitation and discharge of ground water during early summer.

• Korean Journal of Ecology and Environment
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• v.48 no.4
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• pp.263-271
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• 2015

To evaluate the relationship between dynamics of cyanobacteria and odorous compounds, a monthly monitoring of water quality and phytoplankton were conducted at the three serial lakes (Lake Ui-am, Lake Cheong-pyeong and Lake Pal-dang) in the North Han River for 11 times from May 2014 to March 2015. In the three serial lakes, phytoplankton communities showed that seasonal changes in Bacillariophyceae-Cyanophyceae-Bacillariophyceae. Anabaena and Pseudanabaena were dominant species in August and September 2014. At the same time the odors (Geosmin, 2-MIB) were also detected with high concentration. Relationship between environmental factors and cyanobacterial abundance showed a significant correlation with Anabaena circinalis and geosmin (r=0.983, p<0.01). In the case of Pseudanabaena limnetica showed a significant correlation of total nitrogen (r=0.685, p<0.01) and NO3-N (r=0.723, p<0.01). In addition, similarly Pseudanabaena limnetica and 2-MIB (r=0.717, p<0.01) was high. The odorous compounds appeared in the North Han River water were considered to be a direct relationship with cyanobacteria.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.111-120
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• 2003

To describe dinoflagellate cysts from Gwangyang Bay, surface sediment samples were collected at 20 sites by the TFO core sampler on 24 August 2001, in coupled with a phytoplankton investigation by surface seawater sampling. More than 17 genera, 36 species of dinoflagellate cysts were Identified from the sediment samples of Gwangyang Bay, consisting of 14 species of gonyaulacoid, 14 species of protoperidinioid, 3 species of diplopsalid, 2 species of gymnodinioid, 1 species of tuberculodinioid and calciodinellid, respectively. Cyst concentrations in Gwangyang Bay varied from 115 to 2,188 cysts/g, and generally increased toward a western part of the study area. The highest cyst concentration was observed at St. 11 located in the northwestern region with 11 genera and 19 species(2,188 cysts/g), while the lowest value with 6 genera and 9 species(115 cysts/g) was observed at St. 3 located in the center of the study area. The predominant dinoflagellate cyst was Spiniferites bulloideus, followed by Alexandrium sp., Brigantedinium simplex and S. delicatus. The motile forms of eight dinoflagellate cysts recorded in the sediment samples were also observed in the seawater: Polykrikos swartzii/kofoidii complex, Scripssiella trochoidea, Protoperidinium claudicans(cyst name: Votadinium spinosum), P. pentagonum(: Trinovantedinium capitatum capitatum), P. conicum(: Selenopemphix quanta), P. leonis(: Quinquecuspis concretum), P. conicoides(: Brigantedinium simplex), Gonyaulax spp.(: Spiniferites spp.). In this study, heterotrophic dinoflagellate cysts show the highest concentration at St. 6 where the highest density of diatoms simultaneously observed from surface water sample. This result suggests that the grazing of heterotrophic dinoflagellates on the diatoms in high concentration caused the higher concentration of heterotrophic dinoflagellate cysts.

• 한국해양학회지
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• v.21 no.3
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• pp.184-192
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• 1986

A study on the fine structure of the marine diatom has been carried out for taxonomical purpose during the period from Fib. 1982 to Feb. 1986 in Korean coastal waters. Fine structure of small Thalassiosira (Bacillariophyceae) was studied by means of light and scanning electron microscopy. Firstly, four species of Thalassiosira were identified and described. Of these Thalassiosira weissflogii, T.minima and T.oestrupii var venrickae were new records for Korean coastal waters.

• Proceedings of the Korean Aquaculture Society Conference
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• 2003.10a
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• pp.86-87
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• 2003

본 실험은 전복 종묘생산 시 먹이생물로 적합한 부착 규조를 파악하기 위하여 실시하였다. 부경대학교 한국해양 미세 조류 은행에서 보유한 부착 규조종 중, 해역, 크기, 부착력, 영양분석 결과를 고려하여, 11종의 부착 규조를 선택하였다. 각 부착 규조를 f/2 배지로 파판에 배양 한 후 평균 각장 7mm의 까막전복 치패를 대상으로 26일 간 먹이 효율을 조사하였다. 또 이 실험의 결과를 토대로 먹이 효율이 좋은 4종의 부착 규조를 선택하여 참전복 유생의 부착율과 먹이 효율을 조사하였다. 참전복 유생은 수정 후 56 시간이 지난 veliger유생을 이용하여 각 규조에 따른 유생의 부착율, 사망률, 변태율, 성장률을 측정하였다. 까막전복 치패를 대상으로 규조종별 먹이 효율을 실험한 결과, 생존율은 Caloneis schroder가 37.1%, Nitzchia sp. 35.0%, Navicula sp.가 31.4%로 대체로 높은 생존율을 보인 반면에, Navicula elegans이 6.4%, Cylidrotheca closterium.은 11.7%로 낮은 생존율을 보였다. 실험 종료후, 까막전복 각장의 성장을 측정한 결과, Cocconeis californica가 9.33 mm, Achnanthes sp.은 9.27 mm으로 대체로 높은 성장을 보였다. 이에 반해 Navicula elegans은 8.60 mm으로 낮은 성장을 보였다. 전복 전중과 육중은 Amphora sp.에서 각각 87.7mg, 35.2mg 으로 가장 높았으며, Cocconeis californica와 Achnanthes sp.에서도 대체적으로 높게 나타났다. Navicula elegans는 각장의 성장에서와 같이 가장 낮은 증육을 보였다. 규조 4종을 대상으로 한 참전복 유생의 부착율 에서는 수정 후 152시간 후 Cocconies califonica에서 47.3%로 가장 높은 반면, Caloneis schroder 에서 23.8%로 가장 낮았다. 실험 9일째 사망률은 Cocconeis californica에서 63.6%로 가장 낮게 나타났고, Nitzchia sp.에서 90.4%로 가장 높게 나타났다. 유생의 변태율은 Cocconeis californica에서 98.5%로 가장 높은 결과를 보였다. 유생의 일간 성장율 역시 Cocconeis californica에서 25.4 $\mu\textrm{m}$/day로 높았고, Nitzchia sp.에서 13.9 $\mu\textrm{m}$/day로 낮았다. 실험 24일째 참전복 유생의 최종 생존율은 변태율과 일간 성장률이 높았던, Cocconeis californica에서 7.8%로 가장 높게 나타났다.

• ALGAE
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• v.17 no.4
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• pp.217-233
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• 2002

• 수도
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• v.24 no.1 s.82
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• pp.41-47
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• 1997

• Ecology and Resilient Infrastructure
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• v.3 no.1
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• pp.22-34
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• 2016

We developed a biologically-derived substance naphthoquinone (NQ) derivate for the eco-safe mitigation of harmful cyanobacteria blooms such as Microcystis and Dolichospermum. NQ was reacted with various substituents ($R_n$) to produce different NQ derivatives. We tested a total of 92 algicidal compounds based on the algicidal activity of Microcystis and Dolichospermum. 22 compounds of NQ were selected as candidates (algicidal activity >80% at $1{\mu}M$). Among them, NQ 40 compound showed the highest algicidal activity of 99.6% and 100% at the optimal concentration of $1{\mu}M$ on Microcystis and Dolichospermum, respectively. No algicidal effects of NQ 40 ($1{\mu}M$) were observed against non-target algae such as Stephanodiscus, Cyclotella and Peridinium. According to the results of acute eco-toxicity assessment, the $EC_{50}$ values of NQ 40 compound for Selenastrum capricornutum and Daphnia magna were 3.2 and $14.5{\mu}M$, respectively, and the $LC_{50}$ for Danio rerio was $15.7{\mu}M$. In addition, for D. magna chronic eco-toxicity assessment, no toxicity toward survival, growth and reproduction was observed. Therefore, we suggested the NQ 40 ($1{\mu}M$) compound as an alternative eco-safe algicidal substance to effectively mitigate harmful cyanobacteria blooms.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.380-386
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• 2000

Alkaline phosphatase ($AP_{ase}$) activity was studied for the pure cultures and natural communities of phytoplankton. The Michaelis-Menten constant ($K_m$) showed large variation with species. Some green algae showed large $K_m$ ($650\;{\mu}M$ for Selenastrum capriconutum). Chlorella sp. and Nitzschia palea showed smaller Km (respectively1.7, 2.0 HM) than those of other species examined. The extracellular free enzyme in the filtrate of Anabaena flos-aquae showed smaller Km ($52\;{\mu}M$) than that of cellbound form ($276\;{\mu}M$). The $K_m$ ($12.0\;{\mu}M$) of summer phytoplankton in Lake Soyang. when Anabaena sp. was dominant species, was larger than that (1.5 HM) of spring phytoplankton when Asterionella sp. was the dominant. Although maximum activity($V_{max}$) in Lake Soyang was affected by the concentration of DIP within the lake, but the $V_{max}$ always varied not with the DIP concentration of the lake. Induction of $AP_{ase}$ may be more affected by the phosphate content within the cell of phytoplankton than by the concentration of DIP within the lake, The extracellular free $AP_{ase}$ activity accounted for $36{\sim}97%$ of total activity from fall to spring turnover in Lake Soyang. The $K_m$ ($1.1{\mu}3.5\;M$) of extracelluar free enzyme were simillar to those ($0.7{\mu}3.5\;M$) of the total activity. This indicates that the extracelluar free enzyme was derived from phytoplankton.

• 한국해양학회지
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• v.26 no.1
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• pp.67-76
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• 1991

Masan Bay is infamous for its severe eutrophication, exemplified by frequent red tide incidences and anoxic conditions. We carried out daily observations for 16 days at one site immediately after the summer rainy season in 1988 on the basis that shorter observation intervals be necessary to observe a process with high turnover rate. in spite of the relatively short survey period, we could observe dramatic changes in abundance and composition of the phytoplankton populations. Cell densities and chlorophyll concentrations changed in the magnitude of 70 and 10 times, respectively, Skeletonema costatum, a diatom species, dominated the first peak of phytoplankton biomass and was followed by Prorocentrum minimum, a dinoflagellate species, which occurred dominantly in the second peak after about a week, form the viewpoint of time scale, we suggest that at least a weekly sampling might be appropriate in complex coastal environments as Masan Bay. While stratification enabled high production in the surface layer, it hindered the transport of silicate from bottom to the surface, which in turn limited the prolonged growth of diatoms. Ensued second peaks of silicate and diatom abundance in the surface layer suggest periodic flux of silicate from bottom across the discontinuity driven by tidal currents.