• Korean Journal of Ecology and Environment
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• v.50 no.4
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• pp.441-451
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• 2017

The present study was conducted from August to December 2016 in a cylindrical water tank with a diameter of 1 m, a height of 4 m and a capacity of 3,000 L. The field water and sediment from the Nakdong River were also sampled for the experimental culture (field water+sediment) and control culture (field water), respectively. In this study, we aimed to investigate phytoplankton succession pattern using the phytoplankton functional group in the enclosed culture system. A total of 50 species in 27 genera including Chlorophyceae (30 species), Bacillariophyceae (11 species), Cyanophyceae (7 species), and Cryptophyceae (2 species) were identified in the experimental and control culture systems. A total of 19 phytoplankton functional groups (PFGs) were identified, and these groups include B, C, D, F, G, H1, J, K, Lo, M, MP, N, P, S1, $T_B$, $W_0$, X1, X2 and Y. In particular, $W_0$, J and M groups exhibited the marked succession in the experimental culture system with higher biovolumes compared to those of the control culture system, which may be related to the internal cycling of nutrients by sediment in the experimental culture system. The principal component analyses demonstrated that succession patterns in PFG were associated with the main environmental factors such as nutrients(N, P), water temperature and light intensity in two culture systems. In conclusion, the present study showed the potential applicability of the functional group for understanding the adaptation strategies and ecological traits of the phytoplankton succession in the water bodies of Korea.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.6 no.3
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• pp.152-163
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• 2001

Based upon the sedimentological, geochemical and micropaleontological analyses of two sediment cores from the Antarctic Peninsula (AP), three distinct lithological units can be recognized: (1) ice-proximal an/or ice-distal diamictons in the lower part of the cores, accumulated just seaward of the grounding line of the ice shlef until 11,000 yrs BP; (2) diatomaceous mud between 6,000 and 2,500 yrs BP in the middle part, resulted from a large influx of organic materials by enhanced production of open marine condition; (3) diatomaceous sandy mud since 2,500 yrs BP, characterized by an increase in sand content and decrease in TOC and diatom abundance in the lower layers, which reflects the formation of more extensive and seasonally persistent sea ice. Based on the C-14 radiocarbon dating, the sub-ice shlef deposition of the diamicton on the AP western shelf completed around 11,000 yrs BP. Colder condition was reinstated between 12,800 and 11,600 BP with a dropin TOC content and diatom abundance, which is coincident with the Younger Dryas event in the North Atlanticregion. At this time, the ice shelf, that is now absent in the study area, appears to advance as evidenced by an abrupt increase in sea-ice taxa. A climatic optimum is recognized between 9,000 and 2,500 BP, coincide witha mid-Holocene climatic optimum 'Hypsithermal Warm Period' from the other Antarctic sites. During this time, diatomaceous mud accumulated by a large influx of organic materials by enhanced production occurred in openmarine condition. Around 2,500 BP, diatomaceous sandy mud reflects the formation of more extensive and seasonally persistent sea ice, coincident with the onset of the Neoglacial in the Antarctic. Our results provide evidence of climatic change from the Antarctic Peninsula`s western shelf that helps in determining the existence and timing of Holocene milennial-scale climatic events in the Southern Hemisphere.

• Korean Journal of Ecology and Environment
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• v.50 no.1
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• pp.57-69
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• 2017

Overwintering and succession of phytoplankton community with physicochemical and biological characteristics were investigated in pilot culture system. Water and phytoplankton samples were collected twice a week from February 23 to June 28, 2016. A total of 17 overwintering taxa including cyanophyceae, chlorophyceae, bacillariophyceae were identified in the experimental group in winter (February), and these overwintering species showed a marked succession pattern along with environment changes. In the process of phytoplankton succession, a total of 56 species in 28 genera were identified in two (experimental, control) pilot culture system. In the experimental group, 52 phytoplankton species in 24 genera were identified, and the number of taxa was highest in chlorophyceae (35 species), followed by Bacillariophyceae (9 species), Cyanophyceae (5 species) and others (3 species). In the control group, 25 phytoplankton species in 14 genera were classified and these taxa consisted of 17 chlorophyceae, 3 cyanophyceae, 2 Bacillariophyceae and 3 others. The standing crops ranged from 40 to $325,450cells\;mL^{-1}$ in the experimental group, and from 900 to $37,100cells\;mL^{-1}$ in the control group, respectively. The dominant species were represented by Monoraphidium minutum, Microcystis aeruginosa, Rhodomonas lacustris, Ankyra judai and Chlorella vulgaris in the experimental group; and M. minutum and Coenochloris cf. pyrenoidosa in the control group. In conclusion, overwintering and succession of predominant phytoplankton species developed due to interactions of internal environmental factors(physicochemical and biological factors) in the pilot culture system.

• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.311-321
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• 2018

The purpose of this study is to investigate effect of stream channel naturalness on ecological health by using environmental factors and Fish Assessment Index (FAI) in the Han River of South Korea. These samples and data have been released from the research project titled Stream/River Ecosystem Survey and Health Assessment, which was conducted in 444 sites in the Han river watershed from 2008 to 2016. All samples were classified into five groups according to a degree of morphological changes of stream. Water chemistry analyses indicated a decline in water quality by decreasing stream channel naturalness, it is assumed that channelized stream was vulnerable to aquatic pollution compared to the natural meandering stream. In the result of frequency of dominant species, sensitive species and insectivore such as Zacco koreanus, Rhynchocypris kumgangensis and Pungtungia herzi were frequently dominated in the natural meandering stream while tolerant species and omnivores such as Carassius auratus and Cyprinus carpio were more dominated in the channelized streams. The FAI in the channelized stream shows decline to average of $46{\pm}25$ compared with that of the natural meandering stream ($80{\pm}20$). The decrease in FAI was highly influenced by changes in matrixes of fish assemblage structure such as number of sensitive species (M3), portion of omnivores (M5) and insectivores (M6). Moreover, annual average FAIs from 2008 to 2016 were significantly correlated with water chemistry, especially TN, TP and BOD ($r^2=0.59$, p<0.0001). Taken together, all the results suggest that the stream channelization could negatively impact on the water quality and fish assemblage structure, leading to degradation in aquatic ecosystem health.

• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.331-344
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• 2018

Lotic organisms in streams are affected by natural and anthropogenic disturbances such as increase of heavy rainfall event caused by climate change and flow regime change caused by weir constructions. Based on domestic and foreign literature, 157 Korean benthic macroinvertebrate taxa were selected species as potential lotic candidates. Three shoreline sites (total 54 samples) were surveyed consecutively before ('08~'09), during ('10~'12) and after ('13~'16) the construction of the weirs (Gangcheon, Yeoju and Ipo weir) in the Namhan-River for tracing changes of lotic communities. As a result, water flow of the Ipo-wier and water quality variables such as T-N, T-P, BOD5, etc. of the weir section revealed no significant changes. Physical habitat conditions such as the flow velocity and streambed substrate evidently changed. Particulary, flow velocity measured at sampling points along with each microhabitat drastically decreased and particle size of streambed substrate steadily decreased after weir constructions. Lotic organisms also decreased after construction, especially Hydropsychidae (insecta: Trichoptera) acutely decreased from $3,526ind.\;m^{-2}$ to $2ind.\;m^{-2}$ As a result of CCA, lotic species such as Hydropsyche valvata, Hydropsyche kozhantschikovi, Cheumatopsyche brevilineata, Cheumatopsyche KUa, Macrostemum radiatum, etc. correlated with the flow velocity, streambed substrate. Therefore, the decrease of the flow velocity and substrate size after weir construction seemed to be closely related to the decrease of the individual abundances of the lotic organisms independently of water quality. In order to evaluate the influence of the ecosystem on the flow regime change more accurately, it is necessary to study the indicator species based on the resistance or preference of the flow.

• Journal of Haehwa Medicine
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• v.27 no.1
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• pp.9-20
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• 2018

Objectives : Ten heavenly stems(10天干) and Twelve earthly branches(12地支) are symbols exposing change order in heaven and earth, and are a very important sign in studying oriental philosophy and oriental medicine. Especially, 10 heavenly stems(10天干) and 12 earthly branches(12地支) are indispensable for the study of Five Circuits And Six Qi(오운육기), and a deep study is needed. Methods : I have examined Yin Yang combination(음양배합), Five elements combination(오행배합), Six Qi 3Yin 3Yang combination(육기삼음삼양배합), viscera combination(장부배합), Mutual collision(상충), Six combination(육합), Three combination(삼합), etc. of 12 earthly branches(12지지) by referring to books such as "Yellow Emperor Internal Classic" ("黃帝內經") and "Principle of universe change" ("우주변화의 원리"). Results & Conclusions : Zi Yin Chen Wu Shen Xu(子 寅 辰 午 申 戌) become Yang(陽), Chou Mao Si Wei You Hai(丑 卯 巳 未 酉 亥) become Yin(陰), Zi Si Yin Mao Chen Si(子 丑 寅 卯 辰 巳) become Yang, and Wu Wei Shen You Xu Hai(午 未 申 酉 戌 亥) become Yin. Twelve earthly branches can be divided into five movements by its original meaning, where YinMao(인묘) is tree, SiWu(사오) is a fire, ShenYou(신유) is a gold, HaiZi(해자) is water, and ChenXuChouWei(진술축미) mediate in the middle of four movements So they become soil(土). SiHai(巳亥) is JueYin Wind Tree(궐음 풍목), ZiWu(子午) is ShaoYin Monarch Fire(소음 군화), ChouWei(丑未) is TaiYin Humid Soil(태음 습토), YinShen(寅申) is ShaoYang Ministerial Fire(소양 상화), MaoYou(卯酉) is YangMing Dry Gold(양명 조금), and ChenXu(辰戌) is TaiYang Cold Water(태양 한수). Viscera combination(장부배합) combines Zi(子) and Bile(膽), Chou(丑) and Liver(肝), Yin(寅) and Lung(肺), Mao(卯) and Large intestine(大腸), Chen(辰) and Stomach(胃), Si(巳) and Spleen(脾), Wu(午) and Heart(心), Wei(未) and Small intestine(小腸), Shen(申) and Bladder(膀胱), You(酉) and Kidney(腎), Xu(戌) and Pericardium(心包), Hai(亥) and Tri-energizer(三焦), Which means that the function of the viscera and channels is the most active at that time. Twelve earthly branches mutual collisions collide with Zi(子) and Wu(午), Chou(丑) and Wei(未), Yin(寅) and Shen(申), Mao(卯) and You(酉), Chen(辰) and Xu(戌), and Si(巳) and Hai(亥). The two colliding earthly branches are on opposite sides, facing each other and restricting each other by the relation of Yin-Yin and Yang-Yang it rejects each other so a collision occurs. Six Correspondences(六合) coincide with Zi(子) and Chou(丑), Yin(寅) and Hai (亥), Mao(卯) and Xu(戌), Chen(辰) and You(酉) and Si(巳) and Shen(申) Wu(午) and Wei(未). Three combination(三合) is composed of ShenZiChen(申子辰), SiYouChou(巳酉丑), YinWuXu(寅午戌), and HaiMaoWei(亥卯未). Three combination(三合) is composed of ShenZiChen(申子辰), SiYouChou(巳酉丑), YinWuXu(寅午戌), and HaiMaoWei(亥卯未). This is because the time Six Qi(六氣) shifts in these three years are the same.

• Korean Journal of Ecology and Environment
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• v.55 no.2
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• pp.120-131
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• 2022

Microcystins (MCs) are cyano-toxins mainly produced by cyanobacteria in the genera of Microcystis, Anabaena, and Oscillatoria. The concentrations of MCs in the water bodies and fish tissues taken from the four weirs (Ipo, Gangjeong-goryeong, Baekje, and Juksan) in the four main rivers in Korea, and the health risk of human due to consumption of toxin-detected fish was examined. The maximum values of MCs concentration in the water samples were as follows: Juksan (3.261 ㎍ L^-1), Gangjeong-goryeong (1.014 ㎍ L^-1), Baekje (0.759 ㎍ L^-1), and Ipo (0.266 ㎍ L^-1) weirs. The MC-RR concentration was the highest among the MCs, and MC-YR was not detected. MCs of 0.222~9.808 ㎍ g^-1 dry weight were detected in the liver of 3 out of 215 fishes of 16 species, and below the detection limit in muscle. As a result of comparing the feeding characteristics of the collected fishes and toxin concentrations in water and fish tissue, it was concluded that the biomagnification of MCs through the food chain did not occur. It was judged that there was no health risk due to the consumption of the fish detected the toxin, based on the amount of the fish intake of the Korean people and the allowable daily intake of MCs. However, in order to reduce the health risk due to MCs, further studies should be conducted to analyze the concentration of MCs contained in fish tissues collected at various times in the area dominated by harmful cyanobacteria to obtain data on the exposure of MCs due to fish consumption. In addition, it is necessary to establish the management guidelines for MCs in fish tissues.