• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.4
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• pp.2951-2957
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• 2015

The development of worldwide harmful algal blooms(HAB) is a serious problem for public health and fisheries industries. To evaluate the algicidal impact on the HAB species, algicide thiazolidinedione derivative (TD49) and yellow clay were examined, which is focus on assess the algicidal effects and inhibition to photosynthesis of HAB species. To obtain the detailed information, we analyzed the viability of target species related to activity Chl. a, photosynthetic efficiency($F_v/F_m$), and electron transport rate(ETR). Culture experiment was conducted to evaluate the algicidal effects of three harmful species(raphidophyceae Heterosigma akashiwo, Chattonella marina, and dinophyceae Heterocapsa circularisquama) and one non-harmful species (cryptophyceae Rhodomonas salina). Our experiments revealed that three HAB species were easily destroyed of the cell walls after TD49 dosing. Also, they had significantly reducing values of active Chl. a, $F_v/F_m$, and ETR, due to the damage of photosystem II by inter-cellular disturbance. As a result, the algicidal effect(%) for the three HABs were as follows, in the order of greatest to the least: H. circularisquama> C. marina> H. akashiwo. However, the algicidal effect for yellow clay remained to be <30% (p>0.01), implying that it may not have damaged the photosystem II. On the other hand, non-HAB R. salina was promoted at both TD49 and yellow clay treatments. Our results demonstrated that the TD49 is a good agent for the control of HABs H. akashiwo, C. marina, and H. circularisquama, whereas the yellow clay would not be suitable for the field application based on our experimental results.

• Journal of Life Science
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• v.30 no.1
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• pp.26-31
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• 2020

Heterosigma akashiwo is a globally distributed raphidophyte that forms blooms and causes significant losses to the aquaculture industry in many coastal countries. The development of a fast and sensitive detection method is therefore required to facilitate the appropriate warning of harmful algal blooms. In this study, a nuclease protection integrated with sandwich hybridization (NPA-SH) assay was developed to both qualitatively and quantitatively detect H. akashiwo. The NPA, capture and signal probes were designed by nucleotide sequencing of H. akashiwo. The applicability of NPA-SH was evaluated using cultured H. akashiwo cells and field samples collected at Goseong Bay, Korea. The results show that this method has good applicability and effectiveness in analyzing cultured cells and field samples. A linear regression equation for the quantitative analysis of H. akashiwo was obtained, and the lower detection limit of the assay was 1×10⁴ cells/ml. There was no statistically significant difference in the results of H. akashiwo quantitation using NPA-SH compared to those obtained using a microscope. These results indicate that NPA-SH can be a good alternative to the traditional microscopic method used to monitor H. akashiwo.

• Korean Journal of Microbiology
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• v.52 no.1
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• pp.40-48
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• 2016

This study mainly focused on isolation of marine algicidal bacteria associated with phytoplankton blooms and characterization of algicidal activity against harmful algae. Harmful algal blooms (HABs) found naturally in surface waters have caused many environmental problems worldwide. In this study, forty bacterial strains that have capability of inhibiting harmful algal growth were isolated from Masan Bay, Jinhae Bay, Dol Island, Jangmok Bay, and the Tongyeong Sea, Republic of Korea. The bacteria were screened furthermore for the characteristics on algicidal activities against Cochlodinium polykrikoides, Chattonella marina, Skeletonema costatum, Heterosigma akashiwo, Heterocapsa triquetra, Prorocentrum minimum, and Scrippsiella trochoidea. As a result, the algicidal bacteria that were screened from double over layer agar and microscopic counts tests belonged to genera Pseudomonas, Vibrio, Bacillus, Pseudoalteromonas, Ruegeria, Joostella, Marinomonas, Stakelama, Porphyrobacter, and Albirhodobacter. One of the most important HAB species is Co. polykrikoides and the strongest algicidal activity against the dinoflagellate was 94.00% after 6 h treatment with 10% bacterial culture filtrate. In this study, Marinomonas sp. M Jin 1-8, Stakelama sp. ZB Yeonmyeong 1-11 & 1-13, Porphyrobacter sp. M Yeonmyeong 2-22, and Albirhodobacter sp. 6-R Jin 6-1 were found to be as new genera of bacteria having anti-algal activity. These results suggest that these bacteria might play an important role in controlling phytoplankton blooms.

• Journal of the East Asian Society of Dietary Life
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• v.4 no.1
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• pp.1-18
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• 1994

This study is designed to delve into the measuring systems of different periods so as to help with more exact representations of cultures of different periods. The basis of the measuring system in china stems from the huangjong (Huangzhong : the yellow bell) of the period of Huangdi, the length of the bell being the width of 90 black millet grains. Do (Du : width) ; 1 bun=the width of one black millet grain, 1 Chon=10 Buns, 1 Chuk=10 Chons, 1 Jang=10 Cheoks, 1 In=10 Jangs. Ryang (Lyang : volume) ; 1 Yak=the weight of 1,200 grains in the yellow bell, 1 Hab=2 Yaks, 1Seung=10 habs, 1 Du=10 Seungs, 1 Gok=10 Dus. Hyung (Hung : weight) ; 12 Jus=the weight of 1 Yak, 1Yang=24 Jus are equal 1 Hab in weight, 1 Geun=16 Ryangs, 1 Jo=30 Geuns, 1 Seo=4 Jo. In the era of Eun (In) it was decided that the 9-chon length of the Yellowbell shall be 1 Cheok. The Cheok of Ju was set at 4/5 of the length of the yellow bell. The Cheok of Ju breaks into Yongjocheok, Joryegicheok, Pogeumcheok. Yongjocheok, arising from Rohbancheok of the Ju period, is part of Gokcheok also used as a measuring tool for wooden works. The Han cheok has the same length as the yellow bell. The Sang Cheok is 4/5 of the length of the yellow bell. The Tang Cheok was originally the same as the Sang cheok but became longer and longer to be the Long cheok (31.3cm). The length-measuring system used in the three-nation era of Korea includes the gijeom cheil (35.52cm), Ju cheok (25.45cm), sunje Cheok (23.5cm), the Long Tang Cehok (29.706 cm), making 10 Bun 1 Chon and 10 Chon 1 Cheok. The volume-measuring system(Seung) was 198.81 ㎤ before 681 BC in the shilla Dynasty and was 596.42 ㎤ after that. In the seventh year of Kng Munjong of the Koryo dynasty the standard measuring system with the Long Tang Cheok as its basis was adopted, and the standard volume-measuring tools were used under the name of Migok, Daesodugok, Mijangdu, (29.706 cm), making 10 Bun 1 Chon and 10 Chon 1 Cheok. The volume-measuring system(Seung) was 198.81㎤ before 681 BC in the shilla dynasty and was 596.42 ㎤ after that. In the seventh year of King Munjong of the Koryo dynasty the standard measuring system with the Long Tang Cheok as its basis was adopted, and the standard volume-measuring tools were used under the name of Migok, Daesodugok, Kijangdu, Habseung and gokseok. The 1 Seung volumes of theses toolas were 596,447,927 and 1053㎤, respectively. were called Migok, Daesodugok, Mijangdu, Habseung and Gokseok, being respectively 596,447,927, 1053 ㎤, respectively. In the Chosun Dynasty the length of the Yeongjocheos was 27.6 cm or 31.220 in the Sejong era, 29.8 from Heonjong through Gojong, and 30.3 cm after the 6th year of King Kwangmu, and the volume of Du(Mal) also changed like 4.121 or 5.964, 5.187, 23.08 $\ell$, and the 1-Jeonjung also changed like 2.66 or bout 4, 3.45, 3.75 in line with the changes of the length system.

• Journal of Korea Water Resources Association
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• v.48 no.2
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• pp.79-90
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• 2015

In this study, the water quality parameters of Geum-river were estimated using Landsat 8 satellite image data which had launched in March 2013. The goal of this research is to predict HAB and to monitor spatial pattern of total nitrogen (TN) and total phosphorus (TP) because both TN and TP are the dominant factors of the growth of harmful algal blooms (HABs). To investigate the relationship between satellite band reflectance and in situ measurement value, Pearson' correlation coefficient analysis was used. The band2, 3, 4 and 5 reflectance values among 11 bands of Landsat 8 were used which was highly associated with detecting TN and TP. The 20 in situ data set with satellite's overpass time were identified. TN showed positive relation with band 2 (0.48), band3 (0.62), band4 (0.57) at a significance level of p<0.05. TP also showed high correlation for band2 (0.59), band3 (0.59), band4 (0.58) at a significance level of p<0.01. The optimal regression equation models were constructed for TN and TP based on multiple regression equations. The estimated concentration based on derived regression equations of TN and TP were compared with in situ measurement data. Finally, the spatial pattern of the two parameters was able be monitored through mapping on November 12, 2013 and April 21, 2014.

• Journal of Marine Life Science
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• v.5 no.2
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• pp.72-80
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• 2020

A sea dike in the Yeongsan River estuary was constructed in 1981 to supply water and reclaim tidal flats for agriculture, separating the estuary into the freshwater and seawater zones. However, the sluice gates are frequently opened and freshwater is discharged in summer when more rainfall is recorded than other seasons, then converting the estuary to brackish water system. In this study, the direct effect of freshwater discharge was investigated by monitoring daily variation in water properties and phytoplankton size structure before and after the freshwater discharge events from 2013 to 2015. Freshwater discharge resulted in a sharp decrease in salinity and dissolved oxygen (DO) at surface water whereas it increased the turbidity of water column. However, salinity did not decrease sharply in 2014 when freshwater was discharged one day before the monitoring and salinity remained low prior to the monitoring. Levels of nutrients especially dissolved inorganic nitrogen (DIN) increased after the discharge and this contributed to potential limitation of nutrients such as P or Si rather than N in the estuary. Freshwater discharge also caused the changes in phytoplankton biomass (chlorophyll a) and size structure although their responses were different between years. The changes may affect growth of grazers and thus structure of marine food web by alternating food availability in the Yeongsan River estuary.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.2
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• pp.141-151
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• 2010

Harmful algal blooms (HABs), commonly known as red tides, are aquatic phenomena caused by the rapid growth and accumulation of certain microalgae, which can lead to marked discoloration of surface waters, and severe impacts on public health, commerce, and the environment. In South Korea, the red tides have been a serious and recurrent problem, especially along the south coast. Plenty of yellow loess was used to control an outbreak of the red tides for 15 years from 1996 until now. Yellow loess was almost sprayed in the vicinity of a large fish farming industry. In this research, the distribution characteristics and density distribution of zooplankton were investigated in autumn (Oct. 2008) and spring (Apr. 2009) using volume backscattering strength (SV) calculated by the zooplankton collected with north pacific standard (NORPAC) net and the echo intensity measured with ADCP at stations on the study area in the spraying ocean of yellow loess (SOYL), and the non-spraying ocean of yellow ocean (NOYL) by the red tide generating every year. The species number and the individuals per unit volume of the zooplankton collected in NOYL was high and it which was collected in SOYL was low. As a result of comparing the volume backscattering strength ($SV_c$) calculated by species and length of the zooplankton collected with NORPAC net with the volume backscattering strength ($SV_m$) calculated by the echo intensity measured with ADCP at stations on the study area, although $SV_c$ and $SV_m$ of NOYL were generally in agreement, $SV_m$ of SOYL was higher than $SV_c$ 4.3dB, i.e. ADCP is greatly influenced by suspended solid in SOYL. The horizontal distribution map of $SV_m$ at the study area in autumn (Oct. 2008) and spring (Apr. 2009) was drawn. $SV_m$ of SOYL is higher than NOYL and autumn is higher than spring. $SV_m$ can suppress the overestimate or underestimate of $SV_c$.