• Korean Journal of Ecology and Environment
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• v.54 no.3
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• pp.151-155
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• 2021

The application of environmental DNA in the domestic ecosystem is also accelerating, but the processing and analysis of the produced data is limited, and doubts are raised about the reliability of the analyzed and produced biological taxa identification data, and the sample medium (target sample, water, air, sediment, Gastric contents, feces, etc.) and quantification and improvement of analysis methods are also needed. Therefore, in order to secure the reliability and accuracy of biodiversity research using the environmental DNA of the domestic ecosystem, it is a process of actively using the database accumulated through ecological taxonomy and undergoing verification procedures, and experts verifying the resolution of the data increased by gene sequence analysis. This is absolutely necessary. Environmental DNA research cannot be solved only by applying molecular biology technology, and interdisciplinary research cooperation such as ecology-taxa identification-genetics-informatics is important to secure the reliability of the produced data, and researchers dealing with various media can approach it together. It is an area in desperate need of an information sharing platform that can do this, and the speed of development will proceed rapidly, and the accumulated data is expected to grow as big data within a few years.

• Korean Journal of Ecology and Environment
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• v.54 no.4
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• pp.363-373
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• 2021

An ecological niche is defined as the specific role of a species influenced by time, space, and other resources. By investigating overlaps between ecological niches of different species, we could estimate the degrees of interspecific competition. Such studies often use geographic information systems (GIS) to discover niche overlaps between species. In this study, we used GIS to estimate the spatial niches of two Korean frog species(Pelophylax nigromaculatus and P. chosenicus). This enabled us to predict their geographic distributions in order to identify their coexistence regions and distribution patterns. The results confirmed that altitude was an important variable for predicting their distribution, with a correlation with their climatic range. Spatial distributions of the two frog species were highly overlapped, as the distribution range for P. nigromaculatus included most of the range of P. chosenicus, showing a sympatric distribution pattern. Within the coexisting regions, however, the presence sites for the two species did not overlap, implying weak competition. To confirm the principal factors influencing their competitive relationship and reasons for their sympatric distribution pattern, we need more detailed in-depth studies on the diverse environmental variables within the regions where the two species coexist. By doing so, we would be able to identify various mechanisms for avoiding competition in sympatric frog species.

• Korean Journal of Food Science and Technology
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• v.50 no.6
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• pp.601-607
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• 2018

We examined the physicochemical characteristics of radish kimchi supplemented with either 10% boneless or boned sliced gizzard shad (BLGS and BGS, respectively) and compared them to those of untreated kimchi during an eight-week fermentation period. BLGS- and BGS-containing kimchi showed higher acidity, amino nitrogen, and Lactobacillus levels than control kimchi. Furthermore, BGS-containing kimchi showed higher acidity, amino nitrogen, and Lactobacillus levels, and lower reducing sugar contents than BLGS at the optimum- and over-ripened stage. Higher amino nitrogen serves as a good medium for microorganism growth, which produce organic acids, consequently decreasing the reducing sugar, pH levels and increasing the acidity. The preference test showed that the control kimchi was the most preferred at the unripened stage, while the BLGS- and BGS-supplemented kimchi samples in the ripened and over-ripened stages showed similar preferences. In conclusion, our results indicate that gizzard shad-supplemented kimchi shows positive health characteristics, such as low salinity, high amino nitrogen and Lactobacillus levels.

• Korean Journal of Heritage: History & Science
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• v.43 no.1
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• pp.236-259
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• 2010

The examination of sediment distribution in Seongryu Cave shows existence of rocks contrasting with Joseon Supergroup contrary to existing knowledge. Contrasting especially with the Taeback Group, Daegi Formation, Hwajeol Formation, and Dongjeom Formation has been observed. Unlike Taeback area where Dumugol Formation and Makgol Formation are observed on top of Dongjeom Formation, the rocks of this area are not clear in its separation between the two, so that it was named Geunnam Formation. Seongryu Cave has been developed in this Ordovician Geunnam Formation of the Joseon Supergroup. The cave, mostly horizontal, runs in the NE-SW direction, and contains three lakes. The main passage and branches are about 330 m and 540 m, respectively, making the total length of the cave about 870 m (show cave area = 270 m). Through underwater examination, about 85 m-long underwater passage was newly discovered. Various speleothem such as soda straw, stalactite, stalagmite, column, flowstone, rimston, cave shield, cave coral, curtain, bacon sheet, cave pearl, cave flower, helictite and calcite raft can be found in the cave. There are sections with constant flow of cavern water, but the majority of cavern water in the cave come from the ceiling. The most important discovery in this study is the presence of various speleothem in the submerged part of cave passages. Traces of corrosion and/or erosion can be observed in the speleothem in the submerge passage.

• Journal of Food Hygiene and Safety
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• v.34 no.4
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• pp.396-403
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• 2019

Ion-exchange chromatography and ultrafiltration were used to extract anserine from salmon (Oncorhynchus keta). The salmon anserine showed DPPH radical scavenging activity in the range of 7.30% to 31.05% in a dose-dependent manner. This reducing power of salmon anserine also increased as the concentration increased. Metal chelate activity, superoxide dismutase - like activity, and thiobarbituric acid reactive substances assay showed similar results. The anserine also suppressed the increment of the peroxide value and linoleic acid during storage periods. These results suggest that salmon anserine might be useful as a natural antioxidant in various foodstuffs.

• Korean Journal of Heritage: History & Science
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• v.42 no.1
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• pp.40-61
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• 2009

The Cretaceous Gyeongsang Supergroup, composed of clastic sediments mostly deposited in the lacustrine and fluvial environment, is widely distributed in the southern part of the Korean Peninsula. Diverse fossils of plants, molluscs, insects, footprints of dinosaurs, pterosaurs and birds, and eggs, bones, and teeth of dinosaurs have been found from the Gyeongsang Supergroup. New types of dinosaur, pterosaur, and bird tracks recently discovered from the Gyeongsang Supergroup attract great attention from the world. Several tracksites of dinosaurs and birds were designated as Natural Monument and nationally conserved, and many efforts have given to them for nomination of UNESCO World Heritage. Bird tracks from the Gyeonsang Supergroup are Koreanaornis hamanensis, Jindongornipes kimi, Goseongornipes markjonesi, Ignotornis yangi, Uhangrichnus chuni, and Hwangsanipes choughi, which correspond approximately one third of Mesozoic bird tracks recorded from the world. The Gyeongsang Basin of the Korean Peninsula yields world most diverse bird tracks which may be called a paradise of Mesozoic birds and they are important natural heritage providing significant information about evolution and paleogeographic distribution of birds.

• Journal of the Korean Society of Marine Environment & Safety
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• v.25 no.2
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• pp.237-243
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• 2019

Floating platforms made of PE (PolyEthylene) are often located in shallows of seas, rivers or lakes. They are widely used for marine pensions, marine pontoons, marine bridges, etc. These products are characterized by good flexibility, recyclability, chemical resistance and weatherability with corrosion resistance. Existing PE floating platforms have a simple structure in which one pipe is fastened to one bracket, but this has limited application, even if a user modifies the arrangement. Therefore, we developed a structure that allows buoyancy pipes of various sizes to be fastened to one bracket and verified the structural safety of the product using the finite element method. From the results of structural analysis for buoyancy pipes of different diameters, the maximum stress ratio was 0.78 compared with allowable criteria of 1.0, which represented sufficient safety for a model with 500 mm diameter pipes. Based on the results of this study, further research to evaluate the structural safety of various floating platforms can be carried out in the further; it will also be necessary to establish related evaluation criteria.

• Korean Journal of Heritage: History & Science
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• v.40
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• pp.5-34
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• 2007

Archaeological Heritage is material testimony of national and regional history, and it is one of the tourist's attractions. So it has very important meaning and identical value for a local residents. Public concern on the heritage site elevate higher day by day. They are willing to use it for a multiful purpose, cultural, educational, and even commercial one. But Archaeological Heritage is fragile, and visitors can impact negatively for protection and management of the authenticity on the heritage site. In this research I try to compare legal and administrative measure for the protection, management, and culturalization of Archaeological Heritage in many countries. And I suppose sustainable and practical strategies for keeping integrity of heritage.

• Korean Journal of Ecology and Environment
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• v.51 no.4
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• pp.253-258
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• 2018

Phytoplankton community was studied in relation to a typhoon at Bok-gyo Bridge area in Juam Lake, Korea. In August 31, 2000, a typhoon (Prapiroon) was passed by Juam Lake with great power enough to destroy summer stratification of Juam Lake. Destratification resulted in temporal mixing of the whole water column and changed the physical and chemical properties of water bodies, and caused the changes of the biological properties. The transparency decreased from 195 cm before the typhoon to 84 cm after the typhoon with the resuspension of the bottom sediment. In the vertical distribution of the phytoplankton population, the maximum population was measured at depth of 2 m before the typhoon. However, immediately after the typhoon, the population distributed evenly throughout the entire water layers. The carbon biomass of the phytoplankton was also highest at the depth of 2 m before the typhoon, but immediately after the typhoon, it was uniformly distributed throughout the whole water layers. The vertical profiles of the concentrations of chlorophyll a, however, did not show a significant difference before and after the typhoon. The typhoon induced destratification and restratification altered the taxa of the phytoplankton. The major dominant phytoplankton taxa before the typhoon was diatoms including Aulacoseira granulata, but the green algae overwhelmed the diatoms in cell number and biomass after the typhoon. The chlorophycean dominance was replaced by cyanophycean dominance with the heavy rain and descent of water temperture at the end of September.

• Korean Journal of Ecology and Environment
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• v.52 no.2
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• pp.94-104
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• 2019

In this study, we investigated the spatial variation in land use and topographic effects on water quality at the Geum river watershed in South Korea, using the ordinary least squares(OLS) and geographically weighted regression (GWR) models. Understanding the complex interactions between land use, slope, elevation, and water quality is essential for water pollution control and watershed management. We monitored four water quality indicators -total phosphorus, total nitrogen, biochemical oxygen demand, and dissolved oxygen levels - across three land use types (urban, agricultural, and forested) and two topographic features (elevation and mean slope). Results from GWR modeling revealed that land use and topography did not affect water quality consistently through space, but instead exhibited substantial spatial non-stationarity. The GWR model performed better than the OLS model as it produced a higher adjusted $R^2$ value. Spatial variation in interactions among variables could be visualized by mapping $R^2$ values from the GWR model at fine spatial resolution. Using the GWR model, we were able to identify local pollution sources, determine habitat status, and recommend appropriate land-use planning policies for watershed management.