• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1660-1665
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• 2015

Oats (Avena sativa L.) were evaluated in recent years as a promising crop for increasing the nutritional quality of foods, due to their abundance in many bioactive compounds. The objectives of this study were to determine antioxidant compounds and antioxidant activities of nine oat cultivars and investigate the relationships between antioxidant compounds and antioxidant activities in oat cultivars. The contents of total polyphenolics and vitamin E in oat cultivars were analyzed by spectrophotometric methods and normal phase HPLC, respectively. 2,2'-Azino-bis-(3-ethylbenzothiazoline- 6-sulphonic acid) (ABTS) radical and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activities, reducing power, and chelating effects were used to compare the relative antioxidant activities of oat cultivars. In this study, total polyphenolic and vitamin E contents of oat cultivars ranged from 83.41 to 130.59 mg gallic acid equivalents/100 g and 0.54 to 1.90 mg/100 g, respectively. High levels of ABTS radical (116.14 mg Trolox equivalent antioxidant capacity (TEAC)/100 g) and DPPH radical (38.58 mg TEAC/100 g) scavenging activities and reducing power ($A_{700}=0.922$) were found in Daeyang. Significant correlation was evaluated between total polyphenolic contents and their antioxidant activities, namely ABTS and DPPH radical scavenging activities and reducing power. A low correlation was observed between vitamin E contents and their antioxidant activities. The results of this study could have an impact on oat consumption by enhancing consumer awareness of the health benefits of oats.

• Korean Journal of Soil Science and Fertilizer
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• v.34 no.1
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• pp.33-41
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• 2001

Enormous volumes of mining wastes from the abandoned and closed mines are disposed without a proper treatment in the upper Okdong River basin at Southeastern part of Kangwon Province. Erosion of these wastes contaminates soil, surface water, and sediments with heavy metals. Objectives of this research were to fractionate heavy metals in the mine tailing stored in the Sangdong Tungsten tailing dams and to assess the potential pollution index of each metal fraction. Tailing samples were collected from tailing dams at different depth and analyzed for physical and chemical properties. pH of tailings ranged from 7.3 to 7.9. Contents of total N and organic matter were in the ranges of 3.2~5.5%, and 1.3~9.1%, respectively. Heavy metals in the tailings were higher in the newly constructed tailing dam than those in the old dam. Total concentrations of metals in the tailings were in the orders of Zn > Cu > Pb > Ni > Cd, exceeded the corrective action level of the Soil Environment Conservation Law and higher than the natural abundance levels reported from uncontaminated soils. Relative distribution of heavy metal fractions was residual > organic > reducible > carbonate > adsorbed, reversing the degree of metal bioavailability. Mobile fractions of metals were relatively small compared to the total concentrations. Distribution of metals in the tailing dam profiles was metal specific. Concentrations of Cu at the surface of tailing dams were higher than those at the bottom. Pollution index (PI) values of each fraction of metals were ranged from 4.27 to 8.51 based on total concentrations. PI values of mobile fractions were lower than those of immobile fractions. Results on metal fractions and PI values of the tailing samples indicate that tailing samples were contaminated with heavy metals and had potential to cause a detrimental effects on soil and water environment in the lower part of the stream. A prompt countermeasure to prevent surface of tailings in the dams from water and wind erosions is urgently needed.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.1
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• pp.128-138
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• 2019

Effects of feeding type and food resource availability on community structure of mollusks inhabiting hard-bottom subtidal areas were investigated. By following guidance from several references, mollusks observed in this study were divided into 5 groups according to feeding type - 1) grazing, 2) filter feeding, 3) deposit feeding, 4) omnivorous and 5) predation. The results showed that both grazing and filter feeders were the most numerous, explaining grazing type in the East Sea accounting for 47.9%, 32.6% in the South Sea and 29.6% for filter feeding, and filter feeding as a dominant feeding type in Yellow Sea accounting for 42.3%. Results of this study showed distinctive difference in community structure depending on mechanism of feeding type and geographical areas where sampling took place. With the results, attempts were made to understand whether community structure could be affected by feeding type or feeding availability and found out that community structure depended heavily on food resource availability. In the East Sea where marine algal density was high, the algal community in the forms of thick-leathery and sheet often occurred in water column with high transparency which provides proper environment for growth. In the South Sea where grazing and filter feeding types were predominated similarly, the algal density was high, but had the relative highest phytoplankton density. Whereas in the Yellow Sea showing the lowest algal biomass compared to the one in the East and the South Sea, and phytoplankton density was similar to those. It might be a adequate environment for filter feeders than grazers. This study concluded that community structure of mollusks showing high abundance was present where food resource availability with types and quantity was high.

• Journal of Apiculture
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• v.32 no.3
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• pp.139-146
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• 2017

Floral scent emitted from many plants is the critical factors for pollinator attraction and defense for adaptation in environments. The fragrance components of flowers are different in composition by geographical origins, climate factors and the development stages of flowers. In the present study, we investigated the volatile-floral compounds in flowers of Robinia pseudoacacia L. and defined the chemical contribution for flowering periods. The volatile compounds analysis was performed by gas chromatography with mass selective detector after solid phase microextraction (SPME). We reported different compositional features of fragrance compounds according to flowering periods. The abundant compounds identified in stage 1 were ${\alpha}$-pinene (66.80%) and ${\beta}$-pinene (26.53%). Those of the stage 2 were (Z)-${\beta}$-ocimene (37.57%), ${\alpha}$-pinene (15.16%), benzaldehyde (16.63%), linalool (12.13%). The volatiles of stage 3 comprised an abundance of (Z)-${\beta}$-ocimene (64.94%), ${\alpha}$-pinene (9.84%), linalool (8.92%), benzaldehyde (1.71%). Leaf volatiles were distinct from those in the reproductive plant parts by their high relative amount of (E)-${\beta}$-ocimene (23.50%) and (Z)-3-Hexenyl acetate (27.87%). Differences in flower scents of the different stages and leaves are discussed in light of biochemical constraints on volatile chemical synthesis and of the role of flower scent in evolutionary ecology of R. pseudoacacia.

• Korean Journal of Environmental Biology
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• v.39 no.2
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• pp.195-206
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• 2021

In 2020, South Korea initiated research and development of a longitudinal connectivity evaluation between upstream and downstream based on stream ecosystem health. This study analyzed the migration of upstream and downstream migratory fish species, fish distribution characteristics, trophic guilds, tolerance guilds, and species composition changes from 2015 to 2020 at Songrim weir in Yeongok stream, where the cross-structure of an ice harbor-type fishway for fish movement was recently improved. A total of 5,136 fish, including 36 species, were collected and three major migratory fishes were identified, namely, Tribolodon hakonensis, Plecoglossus altivelis altivelis, and Oncorhynchus keta. According to the comparative analysis before (Pre-I) and after (Post-I) improvement of the fishway, the relative abundance of primary freshwater fish increased in the upstream section, while the number of migratory fishes decreased. The fish species that used the fishway in the Songrim weir were Tribolodon hakonensis (58.4%) and Plecoglossus altivelis altivelis(11.8%). According to the Wilcoxon Signed-Rank Test migratory fish showed a statistically significant difference (p<0.05) in the upstream and downstream, showing a biological improvement effect of the crossstructure. On the other hand, the annual change of migratory fish based on the MannKendall trend test did not significantly increase or decrease (p>0.05). Therefore, in the fish passage improvement project, it is necessary not only for physical, hydrological, and structural tests, but also for pre- and post-biological tests on the use and improvement effect of fishway.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.346-362
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• 2021

A sediment control dam is an artificial structure built to prolong sedimentation in the main dam by reducing the inflow of suspended solids. These dams can affect changes in dissolved organic matter (DOM) in the water body by changing the river flow regime. The main DOM component for Yeongju Dam sediment control of the Naeseongcheon River was analyzed through 3D excitation-emission matrix (EEM) and parallel factor (PARAFAC) analyses. As a result, four humic-like components (C1~C3, C5), and three proteins, tryptophan-like components (C2, C6~C7) were detected. Among DOM components, humic-like components (autochthonous: C1, allochthonous: C2~C3) were found to be dominant during the sampling period. The total amount of DOM components and the composition ratio of each component did not show a difference for each depth according to the amount of available light (100%, 12%, and 1%). Throughout the study period, the allochthonous organic matter was continuously decomposing and converting into autochthonous organic matter; the DOM indices (fluorescence index, humification index, and freshness index) indicated the dominance of autochthonous organic matter in the river. Considering the relative abundance of cyanobacteria and that the number of bacteria cells and rotifers increased as autochthonous organic matter increased, it was suggested that the algal bloom and consequent activation of the microbial food web was affected by the composition of DOM in the water body. Research on DOM characteristics is important not only for water quality management but also for understanding the cycling of matter through microbial food web activity.

• Journal of Korea Water Resources Association
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• v.55 no.12
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• pp.1041-1052
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• 2022

This study is to estimate the optimal ecological flow and analysis the spatial distribution of fish habitat for Andong dam downstream reach (4,565.7 km²) using PHABSIM (Physical Habiat Simulation System) and River2D. To establish habitat models, the cross-section informations and hydraulic input data were collected uisng the Nakdong river basic plan report. The establishment range of PHABSIM was set up about 410.0 m from Gudam streamflow gauging station (GD) and about 6.0 km including GD for River2D. To select representative fish species and construct HSI (Habitat Suitability Index), the fish survey was performed at Pungji bridge where showed well the physical characteristics of target stream located downstream of GD. As a result of the fish survey, Zacco platypus was showed highly relative abundance resulting in selecting as the representative fish species, and HSI was constructed using physical habitat characteristics of the Zacco platypus. The optimal range of HSI was 0.3~0.5 m/s at the velocity suitability index, 0.4~0.6 m at the depth suitability index, and the substrate was sand to fine gravel. As a result of estimating the optimal ecological flow by applying HSI to PHABSIM, the optimal ecological flow for target stream was 20.0 m³/sec. As a result of analysis two-dimensional spatial analysis of fish habitat using River2D, WUA (Weighted Usable Area) was estimated 107,392.0 m²/1000 m under the ecological flow condition and it showed the fish habitat was secured throughout the target stream compared with Q₃₅₅ condition.

• Korean Journal of Ecology and Environment
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• v.56 no.1
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• pp.57-69
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• 2023

The objectives of this study were to analyze the fish community structures and distribution characteristics of fisheries resources in the Osip Stream and Wangpi Stream, fishery resources protection areas. For the study, we conducted fish samplings four times in the two streams from April to October 2019. In Osip Stream and Wangpi Stream, we sampled 31 species and 29 species and the dominant species were Zacco platypus (28.6%) and Squalidus multimaculatus(41.7%), respectively. According to the life type of fish species, primary freshwater species were collected 18 species(58.1%) and 21 species(72.4%), and migration fishes were sampled 4 species (12.9%) and 6 species (20.7%) in Osip Stream and Wangpi Stream, respectively. Fisheries resources species showed high relative abundance in June, and the fish biomass was highest in October. As a results of comparing the previous studies with this study, both rivers showed high biodiversity and were found to maintain stable populations of fishes. According to analysis of tolerance guilds, the proportion of tolerant species, based on the number of individuals, was composed of 14.4% and 1.1% in Osip Stream and Wangpi Stream, respectively. This very low ratio of tolerant species confirmed that both streams have very good physiochemical environment conditions. From the above results, it was judged that the fishery resource protection areas of Osip Stream and Wangpi Stream have high ecological function and preservation value. For sustainable use and management of fishery resource protection areas of Osip Stream and Wangpi Stream, it is suggested that biological disturbance management, fish discharge projects considering environmental capacity, efforts to improve the habitat environment, and establishing a fishery resource protection areas management system were necessary as considerations.

• Korean Journal of Environment and Ecology
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• v.37 no.2
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• pp.151-162
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• 2023

This study investigated the characteristics of fish communities and inhabiting status of the endangered species, Rhodeus pseudosericeus, in the Geumdang Stream in Korea from March to October 2021. A total of 1,698 fish in 5 families and 25 species were collected from 7 survey stations during the survey period. The dominant species was Zacco platypus (relative abundance, 46.5%), and the subdominant species was Squalidus gracilis majimae (16.7%), followed by Rhynchocypris oxycephalus (12.0%), Z. koreanus (5.7%), Pungtungia herzi (3.2%), R. pseudosericeus (2.0%), R. notatus (1.9%), and Acheilognathus rhombeus (1.8%). Nine Korean endemic species (36.0%) were collected, including R. pseudosericeus, R. uyekii, Sarcocheilichthys variegatus wakiyae, Microphysogobio yaluensis, S. gracilis majimae, Z. koreanus, Cobitis nalbanti, Iksookimia koreensis, and Odontobutis interrupta. An exotic species, Micropterus salmoides, designated as an invasive alien species (IAS), was collected downstream. The investigation of the habitat patterns of the endangered species (class II), Rhodeus pseudosericeus, showed a habitat range of about 6 to 7 km in the middle of Geumdang Stream (RP-1 to RP-4), and this species inhabited the edge with water depths of 0.3 through 1.0 m with slow water flow and many aquatic plants. According to the community analysis results, the overall dominance and evenness indexes were low, while diversity and richness indexes were high, and the cluster structure was largely divided into upstream and middle-downstream areas. The river health (fish assessment index) evaluated using fish was assessed as good (3 stations), normal (3 stations), and bad (1 station), and water quality was evaluated as good both upstream and downstream. Compared to previous studies, the number of species was relatively similar, and among the species that appeared in the past, 13 species did not appear in this survey, while 6 species appeared for the first time in this survey. Disturbance factors included river construction, many weirs, and the appearance of the ecosystem-disturbing species, M. salmoides. Since Geumdang Strem has high conservation value because it is home to many species in the Acheilognathinae subfamily, including the endangered species R. pseudosericeus, continuous attention and systematic conservation measures are required.

• Korean Journal of Ichthyology
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• v.34 no.3
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• pp.160-171
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• 2022

This study investigated the characteristics of fish communities, habitat characteristics and the age of Lefua costata in the Jusucheon of Gangneung-si, Korea from January to December 2013. The survey collected 23 species belonging to ten families from 6 survey stations. The dominant and subdominant species were Zacco koreanus (relative abundance, 22.1%) and Rhynchocypris steindachneri (20.1%), respectively. The next most abundant species were Tridentiger brevispinis (10.7%), Orthrias nudus (9.7%), Zacco platypus (8.6%), Lefua costata (7.9%), Iksookimia koreensis (6.0%) and Pungitius sinensis (3.0%). Among the fish species collected, one species, P. sinensis, was class II endangered wildlife by the Ministry of Environment, and four species (Z. koreanus, I. koreensis, Silurus microdorsalis and Cottus koreanus), were endemic to Korea. Additionally, five migration fish species (Tribolodon hakonensis, Hypomesus nipponensis, Gasterosteus aculeatus, Oncorhynchus keta and Plecoglossus altivelis) were collected. The similarity index based on species composition and numbers separated fish communites in the Jusucheon according to main section, i.e., uppermost(St. 1), upper (St. 2~4), middle (St. 5), lower (St. 6). Ecosystem health of Jusucheon Stream (fish assessement index) evaluated using fish was assessed as very good (5 stations) and good (1 station). The main inhabit of L. costata was the middle-lower stream of aquatic plants habitats with mud bottoms, very slow water velocity and water depth 40~80 cm. The age groups for L. costata (female) estimated by the frequency distribution of total length in the spawning season (May) indicated that the 24~37 mm is 1-year old, the 38~51 mm group is 2-year old, the 52~63 mm is 3-year old, 64~77 mm is 4-year old and the 80~91 mm is more than 5-year old. Finally, characteristics of fish communities, habitat characteristics and the age of Lefua costata in the Jusucheon was discussed.