• ALGAE
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• v.33 no.1
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• pp.21-35
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• 2018

The phototrophic dinoflagellate genus Scrippsiella is known to have a worldwide distribution. Here, we report for the first time, the occurrence of Scrippsiella lachrymosa in Korean waters. Unlike the other stains of S. lachrymosa whose cultures had been established from cysts in the sediments, the clonal culture of the Korean strain of S. lachrymosa was established from motile cells. When the sulcal plates of S. lachrymosa, which have not been fully described to date, were carefully examined using scanning electron microscopy, the Korean strain of S. lachrymosa clearly exhibited the anterior sulcal plate (s.a.), right sulcal plate (s.d.), left sulcal plate (s.s.), median sulcal plate (s.m.), and posterior sulcal plate (s.p.). When properly aligned, the large subunit (LSU) rDNA sequence of the Korean strain of S. lachrymosa was ca. 1% different from those of two Norwegian strains of S. lachrymosa, the only strains for which LSU sequences have been reported. The internal transcribed spacer (ITS) rDNA sequence of the Korean strain of S. lachrymosa was also ca. 1% different from those of the Scottish and Chinese strains and 3% different from those of the Canadian, German, Greek, and Portuguese strains. Thus, the Korean S. lachrymosa strain has unique LSU and ITS sequences. The abundances of S. lachrymosa in the waters of 28 stations, located in the East, West, and South Sea of Korea, were quantified in four seasons from January 2016 to October 2017, using quantitative real-time polymerase chain reaction method and newly designed specific primer-probe sets. Its abundances were >$0.1cells\;mL^{-1}$ at eight stations in January and March 2016 and March 2017, and its highest abundance in Korean waters was $26cells\;mL^{-1}$. Thus, S. lachrymosa has a nationwide distribution in Korean waters as motile cells.

• Journal of Korean Society of Water and Wastewater
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• v.17 no.4
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• pp.534-541
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• 2003

Membrane processes are now frequently considered for application in drinking water treatment. The biggest impediment for applying membrane processes is fouling that comes from mass flux (such as particle and organic matter) to the membrane surface and its pores due to convection flow through the membrane. Natural organic matter (NOM) has been reported as the most detrimental foulant. Some research also indicated that particles were often the dominant cause of fouling. Therefore, both NOM and particle fouling need to be examined to better understand fouling in ultrafiltration. Two waters from natural sources, Lake Austin water and Missouri River water, were selected. Both waters are relatively hard waters but has significantly different particle concentrations, which will elucidate effects of particles on membrane fouling. Precipitative softening is traditionally designed to remove hardness ions in hard waters but it can also remove particles and organic matter. Therefore, the integrated water treatment with softening and ultrafiltration is proposed as a promising option for hard waters. The three levels of softening were used to represent different degrees of pretreatment to ultrafiltration in terms of organic matter (i.e., NOM fouling) and precipitates (i.e., particle fouling by further precipitation). Results showed that natural particles in Missouri River water was detrimental foulants of ultrafiltration. As the levels of softening were increased, NOM and particle removal was increased, and thus fouling was decreased. Direct images of the surface of the membranes by scanning electron microscopy allowed observation of the different properties of particles caught in fibril networks of natural organic matter.

• Journal of Environmental Science International
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• v.17 no.8
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• pp.833-840
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• 2008

Deoxygenation process in which CBOD(carbonaceous BOD) is biochemically oxidized to reduced inorganic compounds is of great significance in the oxygen demand of stream waters. The CBOD decay rate has traditionally been determined in a laboratory by CBOD bottle incubation method. But in this study, CBOD decay rates were obtained by laboratory incubation method and natural waters experiment. Average CBOD decay rate for the Nakdong river(upper zone) in natural waters were 0.553 $day^{-1}$ during April 2005 to January 2007. The values in the middle and down parts of the Nakdong river in natural waters were 0.384 $day^{-1}$ and 0.252 $day^{-1}$ at the same period of time, respectively. Average CBOD decay rates using by incubation method in the upper/middle/down parts of the main stream in the Nakdong river basin was 0.270 $day^{-1}$, and 0.289 $day^{-1}$, and 0.283 $day^{-1}$ during April 2005 to January 2007, respectively.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.3
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• pp.370-374
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• 2015

Pacific herring Clupea pallasii eggs were attached to the gill net in Korean coastal waters off Busan. To conservation and management the eggs attached to the gill net, we followed the natural hatching in coastal waters from five days after fertilization to the hatching finished, where the temperature was $9^{\circ}C$. The diameter of fertilized eggs was 1.24-1.55 mm (n= 50), and had a segmented pale yellow yolk, no oil globule. Natural hatching had started by 10 days after fertilization. Mass hatching occurred around 11-12 days after fertilization, most of eggs separated from the gill net. Therefore, when the Pacific herring eggs attached in gill net, should be natural hatching-induced in coastal waters during 12-14 days.

• ALGAE
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• v.35 no.3
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• pp.225-236
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• 2020

Gymnodinium smaydae is a newly described mixotrophic dinoflagellate that feeds on only Heterocapsa spp. and Scrippsiella acuminata among 19 tested algal prey. It is one of the fastest growing dinoflagellates when feeding, but does not grow well without prey. To investigate its spatial-temporal distributions in Korean waters, we quantified its abundance in water samples that were seasonally collected from 28 stations along the Korean Peninsula from April 2015 to October 2018, using quantitative real-time polymerase chain reactions. This dinoflagellate had a wide distribution, as reflected by the detection of G. smaydae cells at 23 of the sampling stations. However, this distribution had a strong seasonality; it was detected at 21 stations in the summer and only one station in winter. The abundance of G. smaydae was significantly and positively correlated with chlorophyll a concentration as well as with water temperature. However, there were no significant correlations between the abundance of G. smaydae and salinity, concentrations of nutrients, or dissolved oxygen concentration. During the study period, G. smaydae was present when water temperatures were 7.6-28.0℃, salinities were 9.6-34.1, concentrations of NO₃ were not detectable-106.0 μM, and concentrations of PO₄ were not detectable-3.4 μM. The highest abundance of G. smaydae was 18.5 cells mL^-1 in the coastal waters of Jinhae in July 2017 when the chlorophyll a concentration was 127 mg m^-3 and water temperature was 23.8℃. Therefore, the spatial-temporal distribution of G. smaydae in Korean coastal waters may be affected by chlorophyll a concentration and water temperature.

• ALGAE
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• v.39 no.1
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• pp.1-16
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• 2024

Many dinoflagellates produce bioluminescence. To estimate the intensity of bioluminescence produced by populations of the heterotrophic dinoflagellates Noctiluca scintillans and Polykrikos kofoidii and autotrophic dinoflagellate Alexandrium mediterraneum in Korean waters, we measured cellular bioluminescence intensity as a function of water temperature and calculated population bioluminescence intensity with cell abundances and water temperature. The mean 200-second-integrated bioluminescence intensity per cell (BL_cell) of N. scintillans satiated with the chlorophyte Dunaliella salina decreased continuously with increasing water temperature from 5 to 25℃. However, the BL_cell of P. kofoidii satiated with the mixotrophic dinoflagellate Alexandrium minutum continuously increased from 5 to 15℃ but decreased at temperatures exceeding this (to 30℃). Similarly, the BL_cell of A. mediterraneum continuously increased from 10 to 20℃ but decreased between 20 and 30℃. The difference between highest and lowest BL_cell of N. scintillans, P. kofoidii, and A. mediterraneum at the tested water temperatures was 3.5, 11.8, and 21.0 times, respectively, indicating that water temperature clearly affected BL_cell. The highest estimated population bioluminescence intensity (BL_popul) of N. scintillans in Korean waters in 1998-2022 was 4.22 × 10¹³ relative light unit per liter (RLU L^-1), which was 1,850 and 554,000 times greater than that of P. kofoidii and A. mediterraneum, respectively. This indicates that N. scintillans populations produced much brighter bioluminescence in Korean waters than the populations of P. kofoidii or A. mediterraneum.

• The Korean Journal of Zoology
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• v.37 no.2
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• pp.262-266
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• 1994

The three species, Synolpheus tumidomanus, Spirontocaris orcuota, Heptacarpus futilirostris, are added to the shrimp fauna of the Ulreung Island.S. turn idomanus was reported one time in Korean waters without redescription, and the present report is the second. Heptocawus futilirostris is newly recorded from the East Sea in Korean waters. With the five previously known species, the total eight species are listed and 5. tumidomanus is redescribed.

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.90-94
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• 2001

Wondonins A and B, aromatic alkaloids of an unprecedented skeletal class have been isolated form and association of the sponges Poecillastra wondoensis and Jaspis sp. In addition, four novel bromotyrosine-derived metabolites, psammaplins $A_1$ and $A_2$, aplysinellins A and B, have been isolated from the tropical sponge Aplysinella rhax. The structures of these compounds have been determined on the basis of combined chemical and spectral analyses. The new compounds exhibited significant cytotoxicity and antiangiogenic activity as well as inhibitory activities against farnesyl protein transferase and leucine aminopeptidase. In addition to these compounds, several bioactive metabolites have been isolated from sponges of Korean and tropical waters.

• Ocean and Polar Research
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• v.35 no.1
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• pp.63-68
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• 2013

The European Common Barnacle Balanus perforatus Brugiere (Crustacea, Cirripedia) has been introduced into the east coast of Korea, presumably via the ballast water of ships. The species has since been spreading along both the northern and southern coast to the east, most likely due to alongshore currents. We predicted the potential range expansion of Balanus perforatus in Korean waters using Genetic Algorithm for Rule-set Prediction (GARP), an environmental niche modeling technique. The results show that much of the southern coastal waters of Korea could be colonized by the spread of the nonindigenous species, but that the west coast is unlikely to be invaded. More sampling on the west coast would enhance the predictability of the model. To our knowledge, this is the first report of its kind for predicting marine nonindigenous species in Korean waters using GARP modeling.

• Ocean and Polar Research
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• v.36 no.3
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• pp.235-246
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• 2014

The thalassinidean upogebiid Upogebia yokoyai Makarov, 1938 was first collected and described based on the specimens from the upper tidal flat of sandy shores of Jeju Island, Korea. Although this species was already reported in Japan and Russia, this is the first report of its occurrence in Korea. Upogebia yokoyai differs clearly from other upogebiid species previously recorded in Korean waters, U. major and U. issaeffi, by spinulation of the dactylus and propodus of pereiopod 1. In addition, some morphological comparisons are provided for identification of the three Upogebia species in Korean waters.