• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.1
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• pp.76-87
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• 2014

Chlorophyll a in seawater which is an indicator of phytoplankton biomass and primary production is determined by High Performance Liquid Chromatography (HPLC), Fluorometry and Spectrophotometry. In this study, various methods for chlorophyll a determination in seawater are compared using in situ seawater samples from Korean seas. Three inter-laboratory comparison campaigns were carried out using chlorophyll a standard samples (R0) and in situ seawater samples, collected from the East China Sea (R1) and the East Sea (R2). 6 laboratories by HPLC methods, 4 laboratories by fluorometry, and 3 laboratories by spectrophotometry participated. Precisions, defined as the coefficient of variation (CV) were within 9% in standard samples, 0.8~20% (average: 6.1%) in R1, 4~21% (average: 13.2%) in R2. Discrepancy in three methods was approximately 20% within the range of the sample homogeneity intended the laboratory precision (R1: 8%, R2: 15%). The discrepancy in laboratories was greater than the discrepancy in methods. The chlorophyll a concentrations can be produced within 20% discrepancy in spite of using different methods. It is recommended to consider this 20% discrepancy when using the chlorophyll a data produced by different laboratories and different methods.

• Korean Journal of Environmental Biology
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• v.32 no.3
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• pp.243-249
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• 2014

In this study, we evaluated the toxic effects of heavy metals (Cd, Cu, Zn) on the population growth rate (r) of the marine diatom, Skeletonema costatum. S. costatum. The population growth rate (r) of the species was determined after 96 hrs. of exposure to Cd (0, 0.63, 1.25, 2.50, 5.00, 10.00 ppm), Cu (0, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50 ppm) and Zn (0, 0.31, 0.63, 1.25, 2.00, 2.50, 5.00 ppm). It was observed that 'r' in the control (absence of Cd, Cu and Zn) were greater than 0.05, however suddenly decreased with increased heavy metal concentrations. Cd, Cu and Zn reduced 'r' in a dose-dependent manner and a significant reduction were occurred at concentration of greater than 1.25, 1.25 and 2.50 ppm, respectively. Based on the toxicity, the heavy metal were ranked as Cu>Zn>Cd, with EC50 values of 1.11, 2.13 and 6.84 ppm, respectively. The lowest-observed-effective-concentration (LOEC) of 'r' in exposed to Cd, Cu and Zn were 1.25, 1.00, 2.00 ppm, respectively. Precisely, a concentration of greater than 1.25 ppm of Cd, 1.00 ppm of Cu and 2.00 ppm of Zn in marine ecosystems induced toxic effect on the 'r' of S. costatum. Based on our results, we suggested that the 'r' of S. costatum might be a useful bio indicator for the toxicity assessment of heavy metals in marine ecosystems.

• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.217-231
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• 2018

Planktonic ciliates play an important role in the food web of marine ecosystem as well as a bio-indicator for invasive species from ballast waters or from changing flow of ocean currents due to climate changes. This study was carried out to find some evidences for introduction of such invasive species using ciliate plankton in four major international ports of Korea. We surveyed the seasonal species composition of planktonic ciliate to find out the evidence for the invasive species at Busan, Ulsan, Gwangyang and Incheon ports from February 2007 to November 2008. A total of 45 ciliates species, belonging to 15 genera, were identified during the study period: 33 species occurred at Busan, 31 at Gwangyang, 30 at Ulsan, 18 at Incheon. The abundance of naked ciliates ranged from 566 to $65,151cells\;L^{-1}$ and that of tintinnids 10 to $5,973cells\;L^{-1}$. Based on vector species of ciliates reported from Coos Bay in Oregon, 13 vector species of tinitinnids were identified as follows, Eutintinnus lususundae, E. tubulosus, Favella ehrenbergii, F. taraikaensis, Helicostomella subulata, Stenosemella nivalis, Tintinnopsis ampla, T. beroidea, T. cylindrica, T. directa, T. lohmanni, T. radix, T. rapa. All vector species occurred at Gwangyang port. Most tintinnids were mainly neritic species throughout the survey, while warm water species occurred only in short period at Busan, Ulsan and Gwangyang ports that might be affected seasonally by Tsushima warm current.

• Economic and Environmental Geology
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• v.50 no.6
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• pp.537-544
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• 2017

Stable carbon isotope ratio of carbon dioxide (${\delta}^{13}C_{CO2}$) is used as an important indicator in the researches for global climate change and carbon capture and sequestration technology. The ${\delta}^{13}C$ value has been usually analyzed with Isotope Ratio Mass Spectrometer (IRMS). Recently, the use of Laser Absorption Spectrometry (LAS) is increasing because of the cost efficiency and field applicability. The purpose of this study was to suggest practical procedures to prepare laboratory reference gases for ${\delta}^{13}C_{CO2}$ analysis using LAS. $CO_2$ gas was adjusted to have the concentrations within the analytical range. Then, the concentration of $CO_2$ was assessed in a lab approved by the Korea Laboratory Accreditation Scheme and the ${\delta}^{13}C_{CO2}$ value was measured by IRMS. When the instrument ran over 12 hours, the ${\delta}^{13}C$ values were drifted up to ${\pm}10$‰ if the concentration of $CO_2$ was shifted up to 1.0% of relative standard deviation. Therefore, periodical investigation of analytical suitability and correction should be conducted. Because ${\delta}^{13}C_{CO2}$ showed the dependency on $CO_2$ concentration, we suggested the equation for calibrating the concentration effect. After calibration, ${\delta}^{13}C_{CO2}$ was well matched with the result of IRMS within ${\pm}0.52$‰.

• Korean Journal of Environmental Biology
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• v.20 no.4
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• pp.366-377
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• 2002

This study investigated the ecological environment of Dongguneung, which royal tombs of the Joseon Dynasty aye in. The aim of this study is to do an effective preservation, management and restoration of the royal tomb and garden of the Joseon Dynasty distributed in Seoul and Kyunggi Province through using the data of Dongguneung. In general, Dongguneung contains the predominant Oak class such as Quercus serrata-Quercus mongolica community, while a flatland surrounding its control office, which is often flooded with the rainy season in summer, is mainly Alnus japonica community, Pinus densiflora community ranges around the royal tomb. The subcommunity of Quercus serrata -Quereus mongolica community is distributed into Robinia pseudo-acacia, Pinus rigida, Pinus koraiensis, Carpinus laxiflora and typical subcommunity and so on. In particular, Robinia pseudo -acacia, Pinus rigida and Pinus koraiensis subcommunity, and Alnus japonica community were forested. The soil class of Dongguneung was mainly a sandy loam and its pH was an average of 4.67 (from 4.36 to 5.68). The content of heavy metals including Cu, Pb and Zn etc. in the soil was about twice as much as the natural content in the forest soil. The content of organism and total nitrogen in the topsoil layer was the average of 4.87% and 0.21% respectively, slightly higher than those (organism； 4.55%, total nitrogen； 0.20%) of the forest soil generated from granite bedrock. Cation exchange capacity as the indicator of soil fertility was 15.0 cmol $kg^{-1}$, higher than that in the granite forest soil. However among base exchangeable cations, contents of $Ca^{2+}$ (2.07 cmol $kg^{-1}$), $Mg^{2+}$ (0.40 cmol $kg^{-1}$) and K+ (0.25 cmol $kg^{-1}$) were slightly lower than that. The above results could reflect the need of soil fertilization and liming for the improvement of nutritional status and buffer process.

• Korean Journal of Environmental Biology
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• v.22 no.3
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• pp.351-368
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• 2004

Following the previous experiments, a starvation experiment was conducted to determine the influence of feeding and starvation on the histological and biochemical changes, the morphormetric changes in the sectioned body and the morphometric changes in Rhynchocypris oxycephalus (Sauvage and Dabry). The influence of starvation on nutritional conditions of the histological changes of hepatocyte and intestinal epithelium as hepatosmatic index (HSI), protein, RNA and DNA concentrations of liver in R. oxycephalus was tested. Although the starved group showed higher concentrations of protein, DNA and RNA than the fed group, food deprivation resulted in a decrease in the HSI, hepatocyte nucleus size and nuclear height of the intestinal epithelium. The RNA - DNA ratio appears to be a useful index of nutritional status in R. oxycephalus and may be useful for determining if R. oxycephalus is in a period of rapid or slow growth at the time of sampling. Additionally, the data have been interpreted in detail and some biologically important relationships discussed. The effects of starvation on the morphometrical changes in sectioned body traits, condition factor, viscera index and dressing percentage were determined for evaluating nutritional conditions of R. oxycephalus. Starvation for nine weeks resulted in a decrease in most sectioned traits as well as in condition factor and viscera index (P<0.05). These findings suggest that nutritional parameters used in this study appear to be a useful index for nutritional status in this species. The data has been interpreted in detail and some important body sectioned values of interest to commercial growers discussed. A 75-day study was conducted to determine the effect of starvation on classical and truss parameters in R. oxycephalus. Truss dimensions of almost the entire head and trunk region as well as the abdomen were increased significantly through feeding or starvation (P<0.05). Truss dimensions of the caudal region generally decreased through feeding or starvation, particularly those dimensions at the hind part of the trunk. There were some significant decreases in classical dimensions of the head region during feeding, in relation to body depth characteristics in the trunk and caudal region during starvation, whereas there was only one decreasing classical dimension in the caudal region during feeding. The results of this study indicate that application of the truss network as a character set enforces classical coverage across the body form, discrimination among experimental groups thus being enhanced. Considering that the dimension of the lower part of the head and some truss and classical dimensions were least affected by feeding and starvation, these dimensions may then be useful as a taxonomical indicator to discriminate the species of Rhynchocypris sp. The value of trunk region dimensions with a large component of body depth in R. oxycephalus is most likely to be compromised by variability related to differences in feeding regimes of fish in different habitats.

• Journal of the Korean Institute of Landscape Architecture
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• v.42 no.6
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• pp.60-71
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• 2014

In this study, on the assumption that the urban park originally is imbued with a public welfare ideology, said public welfare ideology and its characteristics were attended to among the various social roles that the urban park currently fulfills. Aspects of welfare meaning in urban parks were attempted to be identified with the former history of urban parks and the movements of the connections between modern parks and welfare territories. The ideologies, benefits and practices regarding the welfare role that the urban park has played from the past to the present were examined and the backgrounds and contexts within which the welfare ideologies have been expressed in the urban park were examined. In order to examine the implicated public welfare ideologies of the urban park, case studies were conducted to identify how they are expressed and practiced in the present times and the facilitation of these parks and public welfare both in the U.S. and the South Korea. The study results of the cases show that expressions of public welfare in urban parks are composed of more specific and visible programs and strategies in the present times, which are different from the simple proclamatory ways in the past. Particularly, in order to visibly practice a public welfare ideology, many-sided integrated designs are conducted along with various public welfare institutions and programs inside and outside of the urban park. The conclusions from this study are as follows. First, the urban park plays a role as a space to realize public welfare ideology, to create welfare benefits and to realize social welfare. Modern urban parks are used as an indicator to measure the actual conditions of social welfare and are a social environmental commodity that can offer universal benefits to urban residents. Second, many-sided integrated designs are tried along with various public welfare institutions at urban parks, which visibly practice public welfare ideologies in the present. In addition, public welfare institutions greatly influence the consistent development of the resources in the urban park. Third, if the detailed utilization of the regional facilities infrastructure could be brought along with multidimensional approaches about the resources in the urban park, it could be much closer to the lives of residents and could secure a space for increasing resident quality of life.

• Journal of Korea Water Resources Association
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• v.54 no.8
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• pp.577-587
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• 2021

Drought is generally considered to be a natural disaster caused by accumulated water shortages over a long period of time, taking months or years and slowly occurring. However, climate change has led to rapid changes in weather and environmental factors that directly affect agriculture, and extreme weather conditions have led to an increase in the frequency of rapidly developing droughts within weeks to months. This phenomenon is defined as 'Flash Drought', which is caused by an increase in surface temperature over a relatively short period of time and abnormally low and rapidly decreasing soil moisture. The detection and analysis of flash drought is essential because it has a significant impact on agriculture and natural ecosystems, and its impacts are associated with agricultural drought impacts. In South Korea, there is no clear definition of flash drought, so the purpose of this study is to identify and analyze its characteristics. In this study, flash drought detection condition was presented based on the satellite-derived drought index Evaporative Stress Index (ESI) from 2014 to 2018. ESI is used as an early warning indicator for rapidly-occurring flash drought a short period of time due to its similar relationship with reduced soil moisture content, lack of precipitation, increased evaporative demand due to low humidity, high temperature, and strong winds. The flash droughts were analyzed using hydrometeorological characteristics by comparing Standardized Precipitation Index (SPI), soil moisture, maximum temperature, relative humidity, wind speed, and precipitation. The correlation was analyzed based on the 8 weeks prior to the occurrence of the flash drought, and in most cases, a high correlation of 0.8(-0.8) or higher(lower) was expressed for ESI and SPI, soil moisture, and maximum temperature.

• Journal of the Korean Institute of Landscape Architecture
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• v.52 no.2
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• pp.79-95
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• 2024

The purpose of this study was to find the changes in the habitat of wild birds caused by climate change in urban rivers and protected areas that greatly require ecological functions. In the future, this study can be used as a management index to protect the urban river ecosystem and maintain the health of sustainable urban rivers, thereby ensuring biodiversity. The Tancheon Ecological and Landscape Conservation Area, selected as a target site, has been affected by climate change. The four seasons of Korea have a distinct temperate climate, but the average annual temperature in Seoul has risen by 2.4-2.8℃ over the last 40 years. Winter temperatures tended to gradually increase. Precipitation, which was concentrated from June to August, is now changing into localized torrential rain and a uniform precipitation pattern of several months. Climate change causes irregular and unforeseen features. Climate change has been shown to have various effects on urban river ecosystems. The decrease in the area of water surface and sedimentary land impacted river shape change and has led to large-scale terrestrialization. Plants showed disturbance, and the vegetation was simplified. The emergence of national climate change indicator species, the development of foreign herbaceous plants, the change of dry land native herbaceous species, and wet intelligence vegetation were developed. Wild birds appeared in the territory of winter-summer migratory. In addition, species change and the populations of migratory birds also occurred. It was judged that fluctuations in temperature and precipitation and non-predictive characteristics affect the hydrological environment, plant ecology, and wild birds connecting with the river ecosystem. The results of this study were to analyze how climate change affects the habitat of wild birds and to develop a management index for river ecological and landscape conservation areas where environmental and ecological functions in cities operate. This study can serve as a basic study at the level of ecosystem services to improve the health of urban rivers and create a foundation for biodiversity.

• Journal of Wetlands Research
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• v.26 no.1
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• pp.62-71
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• 2024

To assess the ecological changes of Korean fir (Abies koreana E. H. Wilson) under climate change conditions, growth and physiological responses were analyzed over a 5-year period in a control group (outdoors) and in a treatment group where the temperature and CO2 levels were elevated to closely resemble RCP 4.5 conditions. The results showed an increasing trend in annual branch length of A.koreana in the climate change treatment group over time. While climate change conditions did not significantly impact the morphological differences of A.koreana leaves, they did influence the biomass of the leaves, suggesting that as climate change progresses, the productivity of A.koreana leaves may decline. On the other hand, the chlorophyll content in A.koreana under climate change conditions was higher in the climate change treatment group, whereas the photosynthesis rate, transpiration rate, water use efficiency and stomatal conductance was higher in the control group. This suggests that an environment with elevated temperature and CO2 could influence an increase in stomatal density, but having a negative impact on photosynthetic reactions. Further research on stomatal density under each environmental treatment will be required to confirm this hypothesis. Additionally, as this study only observed changes in leaf biomass, further empirical research should be considered to understand the changes in biomass of A.koreana under climate change conditions. In conclusion, the environmental adaptability of A.koreana is expected to weaken in the long term under elevated temperatures and CO2.