• Korean Journal of Ecology and Environment
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• v.53 no.4
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• pp.365-373
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• 2020

Biomonitoring Survey and Assessment Manual for lake ecosystem suggest zooplankton collection methods to compare relatively the number of species, population density, and community indices, taking into account the convenience of the field sampling according to the sites' water depth. In this study, the oblique towing and 20 m vertical towing methods presented in the manual were respectively compared with the whole water column-vertical towing and we analyzed the differences and characteristics of zooplankton community information gathered by each collection method. For community indices, there was no difference in the comparison of oblique/vertical towing methods in the shallow lake, but in the deep lake, the diversity and richness indices increased when vertically towing through whole water column rather than when limiting the towing depth to 20 m. In addition, the total zooplankton density collected by the oblique/20 m vertical towing methods was about three times higher than the whole water column-vertical towing method, which means that the density of zooplankton community can be overestimated depending on the collection methods. It appears to be results of differences in the zooplankton density by water layer arising from their vertical distribution and in filtered raw water quantity according to the towing depth/distance. Hence, for zooplankton community information to be used as a functional quantitative indicator representing the entire lake, it would be more appropriate to apply the whole water column-vertical towing method with considering the distribution of zooplankton density by depth and contribution rate of each water layer when converting total zooplankton density.

• Korean Journal of Heritage: History & Science
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• v.55 no.1
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• pp.63-84
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• 2022

One of the ancient nomadic cultures, the Saka is generally regarded as an important intermediary in the ancient Eurasian cultural network. This study is the reinterpretation of the excavations conducted on the Katartobe tombs site of the Saka culture through a joint three-year-long project by the National Research Institute of Cultural Heritage in Korea in collaboration with the Cultural Heritage Research Institute under the National Museum of the Republic of Kazakhstan. The main discussion of the study deals with the burial rituals performed by the community who built the Katartobe tombs by the comparison and review of the various researches on the Saka tombs based on the archaeological artifacts discovered during excavation. The research has shown that the Saka tribes maintained the tradition of burying domesticated animals, such as horses, with its owner and performed burial rituals which often involved the use of fire. The archaeological remains of the Saka also show that the burial rituals like these formed the key aspect of their cultural heritage. The archaeological discoveries also show that the Saka mourners built wooden cists under a single mound when they needed to bury multiple corpses at once and sustained the practice of excarnation when burying the bodies of those who died in the different periods of time. Some burials included a tomb passage which was used not only for carrying the deceased but also for a separate burial ritual. The main discussion of this study also deals with the remnants of bones of animals buried with their deceased owners in the same kurgan, as well as the animal species and their locations in the kurgan, resulting in the discovery of diverse meanings connected with them. The pottery buried in the tombs were largely ceremonial offering vessels, just like others excavated at nearby Saka tombs and located around the buried corpse's head facing toward the west. The excavation of the tombs also shows that two vessels were arranged at the corners of the coffin where the feet are located, revealing the characteristic features of the burial practices maintained by the tribe who built the Katartobe tombs. It may be too early to come to a definite conclusion on the burial practices of the Saka due to the relative lack of research on the kurgans across Central Asia. Excavations so far show that the kurgans clustered in a single archaeological site tend to display differences as well as uniformities. In conclusion, the ancient Central Asian tombs need more detailed surveys and researches to be able to make strides in an effort to restore the cultural heritage of the ancient Central Asian tribes who played a crucial role in the Eurasian cultural landscape.

• Ecology and Resilient Infrastructure
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• v.9 no.4
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• pp.259-268
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• 2022

In this study, seeds of Festuca ovina var. coreana growing in waste coal landfills exposed to heavy metal contamination for a long time were collected, and growth characteristics and heavy metal accumulation capacity were evaluated through greenhouse cultivation experiments with germinated seedlings, and was conducted for the applicability of phytoremediation technology. Concentration gradients of arsenic-treated artificial soil were 25, 62.5, 125, and 250 mg/kg, respectively, lead concentrations were 200, 500, 1000, and 2000 mg/kg, and cadmium concentrations were 15, 30, 60, and 100 mg/kg, respectively In the arsenic, lead, and cadmium-treated experimental groups, the number of leaves of F. ovina var. coreana decreased in all compared to the control group except for the lead-treated groups (200, 500, and 1000 mg/kg). Length growth of the shoot part was increased in all of the arsenic treatment groups compared to the control group, but decreased in all of the root parts. In the 1000 and 2000 mg/kg lead treatment groups, lengths increased compared to the control group, but in the other treatments, they were shorter than the control group. In the case of the cadmium treatment group, all of the shoot parts were increased compared to the control group, and all of the root parts were decreased. In the case of arsenic treatment, the biomass was decreased at all parts and all concentrations compared to the control group. The 200, 500, and 1000 mg/kg lead treatments showed larger biomass than the control group in both shoot and root parts. In the cadmium treatment group, the biomass of both shoot and root parts decreased compared to the control group. As the concentration of heavy metal treatment increased, both the number of leaves and the biomass by plant parts tended to decrease, and the length growth of the shoot part tended to increase slightly, but the root part tended to decrease slightly. The arsenic accumulation concentrations of the shoot and root parts of the 62.5 mg/kg arsenic treatment area were 9.4 mg/kg and 253.3 mg/kg, respectively. While the shoot part of the 250 mg/kg arsenic treatment area withered away, the arsenic accumulation concentration in the root part was analyzed to be 859.1 mg/kg, In the 2,000 mg/kg lead treatment area, the shoot and root parts accumulated 10,308.1 and 11,012.0 mg/kg, which were 1.1 times higher than the root parts. At 100 mg/kg cadmium treatment, the shoot and root parts were 176.0 and 287.2 mg/kg, and the root part accumulated 1.6 times higher than the shoot part. As a result of tolerance evaluation of F. ovina var. coreana, multi-tolerance to three heavy metals was confirmed by maintaining growth without dying in all treatment groups of arsenic, lead, and cadmium. Plant extraction (phytoextraction) of F. ovina var. coreana was verified as a species that can be applied up to 2,000 mg/kg of soil lead contamination.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.4
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• pp.489-495
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• 1996

Seedling emergences of four rice varieties (Dongjinbyeo, Dadajo, Galsaekggarak-sharebyeo, and Italiconaverneco) and three barnyardgrass species(Echjnochloa oryzjcola, E. crus-gali var. crus gali E. crus-gali var. praticola) were evaluated in relation to soil strength. Soil strength was varied by compressing the entire volume of soil with a hydraulic jack so as to be 0.5, 1, 2, 3, 6kg /$\textrm{cm}^2$. Soil strength was measured with a penetrometer (Yamanaka type) and soil covering above the seed was 4cm deep. Experiments were conducted at two air temperature conditions of 17 and $25^{\circ}C$. At a soil strength of up to 2kg/$\textrm{cm}^2$, little or no decrease in seedling emergence occurred in all rice varieties and barnyardgrasses tested. Above that value, seedling emergence decreased progressively as the soil strength increased. The degree of decrease was greatest in Dongjinbyeo and smallest in Dadajo among tested rice varieties, and greatest in Echinochloa oryzicola among barnyardgrasses, being greater in barnyardgrasses than rice. Seedling emergence was delayed almost linearly as the soil strength increased. The delay was greatest in Dongjinbyeo among rice varieties and in Echinochloa oryzicola among barnyardgrasses. Mesocotyl length increased as soil strength increased up to 2 to 3kg / $\textrm{cm}^2$ in Dongjinbyeo and Dadajo in 17$^{\circ}C$ and $25^{\circ}C$, and up to 6kg/$\textrm{cm}^2$ in Galsaekggaraksharebyeo and Italiconaverneco in $25^{\circ}C$. Dongjinbyeo showed the least elongation of mesocotyl among rice varieties in any soil strength. The total length of mesotyl, first internode and incomplete leaf showed little variation with soil strength. The total length was longer than the 4cm covering depth in other varieties except Dongjinbyeo. This might have caused the lower emergence rate in Dongjinbyeo than other varieties in higher soil strength.

• Korean Journal of Environment and Ecology
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• v.37 no.1
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• pp.86-93
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• 2023

This study investigated the ecological characteristics of Odontobutis interrupta at the Geumdang Stream from January to December 2021. The riverbed structure of the species habitat was rich in sand and mud. The water was deep, ranging from 21 to 124 cm, with an average of 48 cm. The stream velocity was slow at 0.24 (0.08-0.36) m/sec. The ratio of females to males was 1:0.98, and the total length of collected individuals ranged from 23 mm to 162 mm. The age according to the total length-frequency distribution as of May indicated that the group with a total length of 23-59 mm was one year old, the group with 60-99 mm was two years old, the group with 100-139 mm was three years old, and the group with 140-162 mm was four years old. As a secondary gender characteristic, the females genital papilla had a cylindrical shape, a hollow inside of the tip, and a longer diameter than males. The males had a cone shape with a pointed end. Sexually mature males had the nuptial color, with a black abdomen and whole body. Some females with a length ranging from 60 to 69 mm and all females 70 mm longer were sexually mature. Some males with a length ranging from 70 to 79 mm and all males 80 mm longer were sexually mature. The spawning season was from May to July, and the water temperature was between 19.6℃ to 29℃ during that period. The prosperous spawning season was June (26℃). The average number of eggs in the ovaries was 2,473 (883-4,955) per matured female, and the matured eggs were yellowish and spherical with a mean diameter of 1.42 (1.20-0.54) mm. The correlation between total length and weight was BW=0.0000006TL^3.21 with the constant a as 0.0000006 and parameter b as 3.21. The condition factor (K) was 1.67 (1.18-2.43) on average, and the slope was 0.116.

• Journal of Wetlands Research
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• v.25 no.3
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• pp.184-195
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• 2023

To develop an effective management plan for Ambrosia trifida L., an invasive alien plant in Korea, we assessed the potential of Ophraella communa LeSage as a biological control agent. This involved investigating the host specificity of the herbivore Ophraella communa LeSage, its annual travel distance, and the impact of this insect on the fitness of Ambrosia trifida L. We confirmed the host plant preference of Ophraella communa LeSage. The travel distance of this insect was determined by monitoring its appearance in selected Ambrosia trifida L. communities without these insects at distances of 10, 20, 30, and 100 meters, based on the locations where the presence of Ophraella communa LeSage was observed. The growth, reproductive, and physiological responses of Ambrosia trifida L. were measured according to feeding by Ophraella communa LeSage. As a result, Ophraella communa LeSage fed on only three taxa and moved short distances within a radius of 30 m per year from the host. The feeding behavior of the herbivore had a negative impact on the growth, reproductive, and physiological responses of Ambrosia trifida L. And the plant's growth and reproduction improved with increasing distance from the herbivore. Furthermore, the introduction of herbivores was able to control over 90% of Ambrosia trifida L. when the coverage of the Ambrosia trifida L. group was below 50%. However, the effectiveness of the removal decreased when the coverage exceeded 90%. These results are likely to be utilized by Ophraella communa LeSage as an ecological control agent. It is advantageous to introduce them in spring (May) when the coverage is low to maximize the effectiveness of control.

• Journal of Life Science
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• v.32 no.3
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• pp.202-209
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• 2022

The green alga Chlamydomonas reinhardtii, a unicellular haploid eukaryote, has long been used by researchers and industries as a cell factory to produce high value-added microalgae substances using genetic modification. Microalga K01, presumed to be Chlamydomonas, was isolated from 12 freshwater samples from the Chungcheong and Jeolla regions to replace C. reinhardtii, an introduced species currently used in most basic and industrial research. The isolated K01 strain was identified as C. reinhardtii through morphological and phylogenetic studies of the 18S rDNA gene sequence (NCBI accession number KC166137). The growth and lipid content of the isolated C. reinhardtii K01 were compared with three wild and four mutant strains in TAP medium, and it was found that the K01 strain could produce 1.74×10⁷ cells/ml by the third day of culture. The growth rate of C. reinhardtii K01 was 1.5 times faster than UTEX2244, which showed the highest number of cells (1.20×10⁷ cells/ml) among the compared strains. The lipid content of the isolated C. reinhardtii K01 (20.67%) was similar to those of the wild strains, although the fatty acid oleate C18:1 was not detected in the isolated strain but was identified in the seven others. The cell density of the isolated strain increased to 0.87 g/l during a six-day culture in BG11 medium, where nitrate (NaNO₃) was introduced as a nitrogen source, while the seven acquired strains showed almost no cell proliferation.

• Economic and Environmental Geology
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• v.56 no.3
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• pp.301-310
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• 2023

Ferrihydrite is an iron oxide mineral that is easily found in the natural environment, including acid mine drainage, and has a low crystallinity and high specific surface area, resulting in high reactivity with other ions, and can remove environmentally hazardous substances. However, because ferrihydrite is a metastable mineral, there is a possibility of releasing adsorbed ions by phase transformation to other minerals having low surface area and high crystallinity. In this study, the adsorption characteristics of arsenate, chromate, and selenate on ferrihydrite and the oxyanion removal efficiency of ferrihydrite were studied considering mineral phase transformation. At both pH 4 and 8, the adsorption of oxyanions used in the study were in good agreement with both Langmuir and Freundlich adsorption models except for selenate at pH 8. Due to the difference in surface charge according to pH, at pH 4 a higher amount of ions were adsorbed than at pH 8. The adsorption amount were in the order of arsenate, chromate, and selenate. These different adsorption models and adsorption amounts were due to different adsorption mechanisms for each oxyanions on the surface of ferrihydrite. These adsorption characteristics were closely related to changes in the mineral phase. At pH 4, a phase transformation to goethite or hematite was observed, but only a phase transformation to hematite was observed at pH 8. Among the oxyanion species on ferrihydrite, arsenate showed the highest adsorption capacity and hardly caused phase transformation during the experimental period after adsorption. Contrary to this, chromate and selenate showed faster mineral phase transformation than arsenate, and selenate had the lowest retardation effect among the three oxyanions. Ferrihydrite can effectively remove arsenate due to its high adsorption capacity and low phase transformation rate. However, the removal efficiency for other two oxyanions were low by the low adsorption amount and additional mineral phase transformation. For chromate, the efficient removal is expected only at low concentrations in low pH environments.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.426-441
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• 2023

This study investigated the predictive accuracy of a model of landslide displacement in Jecheon-si, where a great number of landslides were triggered by heavy rain on both natural (non-clear-cut) and clear-cut slopes during August 2020. This was accomplished by applying three flow direction methods (single flow direction, SFD; multiple flow direction, MFD; infinite flow direction, IFD) and the degree of root cohesion to an infinite slope stability equation. The application assumed that the soil saturation and any changes in root cohesion occurred following the timber harvest (clear-cutting). In the study area, 830 landslide locations were identified via landslide inventory mapping from satellite images and 25 cm resolution aerial photographs. The results of the landslide modeling comparison showed the accuracy of the models that considered changes in the root cohesion following clear-cutting to be improved by 1.3% to 2.6% when compared with those not considered in the area under the receiver operating characteristics (AUROC) analysis. Furthermore, the accuracy of the models that used the MFD algorithm improved by up to 1.3% when compared with the models that used the other algorithms in the AUROC analysis. These results suggest that the discriminatory application of the root cohesion, which considers changes in the vegetation condition, and the selection of the flow direction method may influence the accuracy of landslide predictive modeling. In the future, the results of this study should be verified by examining the root cohesion and its dynamic changes according to the tree species using the field hydrological monitoring technique.

• Journal of Korean Society of Forest Science
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• v.112 no.4
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• pp.417-425
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• 2023

The aim of this study was to derive stem taper equations for Quercus acuta, one of main evergreen broad-leaved tree species found in warm temperate regions, and to prepare a stem volume table using those stem taper equations. A total of 688 individual trees were used in the analysis, which were collected from Jeonnam-do, Gyeongnam-do, and Jeju-do. The stem taper models applied to derive the stem curve pattern were the Max and Burkhart, Kozak, and Lee models. Among the three stem taper models, the best explanation of the stem curve shape of Q. acuta was found to be given by the Kozak model, which showed a fitness index of 0.9583, bias of 0.0352, percentage of estimated standard error of 1.1439, and mean absolute deviation of 0.6751. Thus, the stem taper of Q. acuta was estimated using the Kozak model. Moreover,thestemvolumecalculationwasperforme d by applying the Smalian formula to the diameter and height of each stem interval. In addition, an analysis of variance (ANOVA) was conducted to compare the two existing Q. acuta stem volume tables (2007 and 2010) and the newly created stem volume table (2023). This analysis revealed that the stem volume table constructed in the Wando region in 2007 included about twice as much as the stem volume tables constructed in 2010 and 2023. The stem volume table (2023) developed in this study is not only based on the regional collection range and number of utilized trees but also on a sound scientific basis. Therefore, it can be used at the national level as an official stem volume table for Q. acuta.