• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.34-42
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• 2016

In order to prepare for the type approval test for the United States Coast Guard (USCG) Phase-II of Ballast Water Treatment System (BWTS), a phytoplankton mass culture was conducted in a mesocosm enclosure. We evaluated the response of the phytoplankton community after nutrient addition (+N, +P, and +NP) and investigated the development of the species with increasing culture time. After nutrient dosing, the phytoplankton population significantly (p < 0.05) increased from day 1 to day 3, depending on the nutrient treatments In particular, the specific growth rate of the phytoplankton community in the case of +NP treatment and + N treatment were estimated to be $2.47d^{-1}$ and $1.98d^{-1}$, respectively. The phytoplankton population density in the case of + NP treatment was approximately 50 times higher than that of the control group, suggesting that these treatments could be useful for mass culturing phytoplankton (> 75% of natural community) for the approval regulation of USCG Phase-II. In the phytoplankton community of the mesocosm, Pseudo-nitzchia spp. dominated in the logarithmic growth phase. The cell density decreased significantly (p < 0.05) with increasing time, coinciding with the nutrient limitation. At that time, the dominance of Pseudo-nitzchia spp. shifted to that of Cylindrotheca closterium. Therefore, the optimum nutrient concentration ($N:30{\mu}M$, $P:3{\mu}M$) and reasonable harvesting time (after 3 days in summer) found in this study for the mass culturing of phytoplankton may be helpful to meet the USCG Phase-II biological criteria to be used in BWTS.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.41 no.5
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• pp.619-624
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• 1996

An experiment was carried out to find out the effects of water foxtail on weed control and rice yield as well as on the reduction of nitrogen application in no tillage transplanted paddy field. Paddy field was dominated by water foxtail whose soil covering degree was adjusted from 8 to 6 by treatment of paraquat (70 l /10a of solution diluted by 1, 000 times). Thirty five-day old seedling was mechanically transplanted and reduced nitrogen, 80% of conventional application was applied at the paddy field. The higher failure in seedling stand was observed at higher degree of soil covering by water foxtail. The failure of seedling stand with covering degree of 8(no paraquat) was 37.4%, while that of covering degree of 6(paraquat-treated) was 12.3%. However, the seedling stand failure was completely recovered at covering degree of six at two weeks after transplanting. The mechanical transplanting made water foxtail in the paddy field fall on the ground whose panicle part was recovered from falling sometimes after transplanting and whole plant died with slow scenesence untill the late of June. But the water foxtail affected by paraquat produced the new panicle from uppernode of stem with dead leaves at early of June and it become die slowly untill the early of July. Though several rice field weeds were observed in the order of Echinochloa crusgallis, Cyperus serotinus, Lemma paucicostata during the active tillering stage of rice, the value of weed control due to the dominance of water foxtail was 77~78%. The death and subsequent decay of water foxtail during the active tillering stage of rice induced the soil reduction which again defect the growth of rice root. The more vigerous rice growth was observed in the plot dominated with water foxtails, than control plot. The yields of rice in the water foxtail (degree 6) plot was 629kg per l0a as brown rice, the same as that of control plot. In conclusion, the no-tillage transplanting with control of covering degree of water foxtail (to degree 6) was effective in reduction of input cost such as herbicide and nitrogen fertilizer, as well as weed control without reduction of rice yield.

• Korean Journal of Ecology and Environment
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• v.39 no.4 s.118
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• pp.498-507
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• 2006

The main objective of present study was to evaluate how seasonal rainfall influenced natural habitat conditions of 10 metric habitat variables along with ionic conditions and suspended solids in the Woopo Wetland during August 2002-July 2003. Largest spatial variabilities in total suspended solids (TSS) occurred during the summer monsoon and the inorganic suspended solids (ISS), expressed as a inorganic proportion of total solids, showed linearly increasing trend from the upstream to downstream. This phenomenon was mainly attributed to counter flow of turbid water from the main Nakdong-River. During the flooding, ISS : TSS ratio showed large increases (92%) in the downstream than the upstream (43%). For this reason, transparency declined (mean=0.13 m, range=0.08-0.21 m) largely in the downstream reach and thus, chlorophyll-a concentration showed low values (range: $4.2-8.6\;{\mu}g\;L^{-1}$), indicating a direct influence on primary productivity or algal growth by inorganic turbidity. In the 2nd survey, ISS averaged 4.0 mg $L^{-1}$ (3.3-4.8 mg $L^{-1}$), thus the ISS decreased by 14 fold, compared to the ISS in the 1st survey during the flooding, while organic suspended solids (OSS) values were greater than those of ISS, indicating a dominance of organic solids. This condition was similar to solid contents in the 3rd survey, but showed a large difference compared to the 4th survey during the growing season. Habitat health assessments, based on 10 metric habitat variables, showed that QHEI values were greatest in the growing season (May) than any other seasons and largest spatial variations occurred in the 2nd survey. Overall, dataset suggest that seasonal episodic flooding during the monsoon may largely contribute nutrient cycling and sediment contents in the Woopo Wetland and Topyung Stream.

• Korean Journal of Ecology and Environment
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• v.35 no.2 s.98
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• pp.63-70
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• 2002

Long-term changes of the fish fauna and its community structure from the Jungrang Creek of the Han River system in Seoul were investigeted from 1990 to 2000. Total species occurred during the survey period were 14 species in 6 families, and total individual number was 108,366. Fishes at the Jungrang Creek had not been distributed in the 1980s and 1990 because of heavy water pollution as well as environmental damage in the riparian areas. However, Cyprinus carpio and Carassius auratus in cyprinidae were rehabitated since the early 1990s when the water quality was improved because of foundation of sewage division pipe. Species nombers gradually increased to 6 species in 1996, 9 species in 1998, and 11 species in 2000. Individual numbers rapidly increased to 164 individuals in 1996, 146 individuals in 1998, and 108,094 individuals in 2000. A large number of Cyprinus carpio and Carassius auratus, which are abundantly distributed in the main course of the Han River, were found when they migrate to the upper reaches of the Jungrang Creek for spawning. Mass fish floatings were occurred on the 21st of April and the 11th of June in 2000 due to DO depletion at the lower site (Site 4) of discharging point of Jungrang sewage treatment plant and stagnant spot(Site 3) of dammed pool. Major dominant species were Cyprinus carpio and Carassius auratus (Cyprinidae). Others dominant species were Pseudorasbora lab대 (Cyprinidae) and Silurus asotus (Siluridae). Dominance indices were relatively high (0.79 to 1.00). Species diversity andrichness indices were relatively low (0 to 1.66and 0 to 1.41, respectively). Species diversity and richness indices were slightly higher at the middle reaches (Site 2 and Site 3) than the upper reaches and the mouth of the Jungrang Creek. However, the fish fauna of the Jungrang Creek was very poor and its community structure was very simple.

• Korean Journal of Ecology and Environment
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• v.39 no.2 s.116
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• pp.145-156
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• 2006

The objective of this study was to evaluate biological health conditions and physicochemical status using multi-metric models at five sites of the Keum-Ho River during August 2004 and June 2005. The research approach was based on a qualitative habitat evaluation index (QHEI), index of biological integrity (IBI) using fish assemblage, and long-term chemical data (1995 ${\sim}$ 2004), which was obtained from the Ministry of Environment, Korea. For the biological health assessments, regional model of the IBI in Korea (An,2003), was applied for this study. Mean IBI in the river was 30 and varied from 23 to 48 depending on the sampling sites. The river health was judged to be "fair condition", according to the stream health criteria of US EPA (1993) and Barbour et al. (1999). According to the analysis of the chemical water quality data of the river, BOD, COD, conductivity, TP, TN, and TSS largely varied epending on the sampling sites, seasons and years. Variabilities of some parameters including BOD, COD, TP, TN, and conductivity were greater in the downstream than in the upstream reach. This phenomenon was evident in the dilution by the rain during the monsoon. This indicates that precipitation is a very important factor of the chemical variations of water quality. Community analyses showed that species diversity index was highest (H=0.78) in the site 1, while community dominance index was highest in the site 3, where Opsariichthys uncirostris largely dominated. In contrast, the proportions of omnivore and tolerant species were greater in the downstream reach, than in the upstream reach. Overall, this study suggests that some sites in the downstream reach may need to restore the aquatic ecosystem for better biological health.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.190-198
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• 2010

This study was conducted to examine the effects of dams on benthic macroinvertebrate communities in Korean streams and rivers. Four low-head dams and three large dams were studied throughout South Korea. Sampling was taken at immediately upper (impoundment), lower (riffle area), and control (riffle area) sites from the dams during 2004-2007. The upper sites, of which substrate heterogeneity and velocity were relatively low, showed a lower degree of species richness, density, and diversity indices, which is very different from the lower and control sites. Heavily polluted streams showed a lesser degree of community differences between the upper and lower sites. In the large dams, the upper and lower sites showed very low values of species diversity indices and very high values of dominance indices compared to the control sites. In the low-head dams, however, the difference of degree of the values was relatively smaller. Compositions of the functional feeding groups and the habitat orientation groups were relatively simpler at the upper sites than at the lower sites and the degree of difference was greater in the large dams. Species richness and community indices of benthic macroinvertebrates were more significantly affected by habitat characteristics than water quality at the upper sites; however, those were more significantly related with water quality at the lower sites. In conclusion, large and low-head dams could simplify stream habitats particularly at the upper sites (impoundment), and they negatively affected on the benthic macroinvertebrate communities inhabited the habitats. The impact was larger in the large dams than in the low-head dams.

• Journal of Life Science
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• v.20 no.6
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• pp.825-830
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• 2010

Two diallelic markers at candidate gene loci, the prolactin receptor 3 (PRLR3) gene and the retinol-binding protein 4 (RBP4) gene were evaluated for their association with growth and litter size traits in Berkshire. Genetic evaluation was conducted for 5,919 pigs with pedigree information, which included 3,480 growth performance records and 775 litter size records of 224 sows. From the same herd, genotyping was carried out on 144 and 156 animals for PRLR3 and RBP4, respectively. After assigning a genotype to subjects in which both parents had a homozygous genotype, numbers of genotyped animals increased to 474 and 338, for the PRLR3 gene and RBP4 gene, respectively. The genotype effects of two markers were estimated with breeding values of the genotyped animals. The additive effects of total number of piglets born and number of piglets born alive in the PRLR3 locus were -0.28 and -0.13, respectively. The dominance effect of the RBP4 locus on average daily gain was -10.58 g. However, the polymorphism of the RBP4 locus in total number of piglets born and number of piglets born alive has shown -0.34 and -0.33 of the additive genetic effects. In view of the results, MAS (marker-assisted selection) favoring B alleles of RBP4 and PRLR3 loci could potentially accelerate the rate of the genetic improvement in the litter size traits.

• The Korean Journal of Air & Space Law and Policy
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• v.33 no.1
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• pp.147-174
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• 2018

The air transportation industry is a field where control and interference of the state are generalized compared to other industries. However, the premise for national intervention in the air transportation industry is the determination of the nationality of the aircraft or airline company concerned. This is because it is necessary to clarify the distinction between the domestic and foreign carriers so that they can exercise airspace sovereignty. The purpose of this paper is to compare the current status and contents of Korean law and regulations on the determination of nationality with the foreign legal system. To this end, the starting point of the discussion is to look at the history of nationality restrictions on the US air transport industry and the issues that arise in the content and operation of the system today. In addition, this paper examined the provisions of the Japanese aviation law, which is very similar to that of Korea, and then compared the current legal provisions of the United States, Japan and Korea. As a conclusion, this paper sought the direction of revision of the Korean law on the basis of the foreign status of the restriction of nationality in the air transportation industry. Compared with our law, the US and Japan are generally regarded to be more concerned with the contents of their own airline companies than those of foreigners or non-citizen. In spite of the fact that there are many laws and regulations in the United States regarding the de facto dominance of domestic airline companies by foreigners, there have been a lot of controversies in this matter. By the way, Japan has been stipulating regulations on holding companies and affiliated companies. In the global era, it would be meaningful to check the status of the nationality restrictions in the aviation industry, which is based on internationality. I hope that this study will be able to build a legal institutional basis for Korea's aviation industry development from a reasonable protectionist point of view rather than a narrow nationalism in a rapidly changing era.

• Korean Journal of Environment and Ecology
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• v.29 no.4
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• pp.570-579
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• 2015

Lindera sericea, which belongs to genus Lindera in the Lauraceae family, is labeled under Least Concerned (LC) among Korean rare plants, floristics specific species IV grade and also flagpole species of the Mudeung National Park. It is distributed in Mt. Mudeung, Mt. Cheonbong and Mt. Chogye within gradients from $12^{\circ}$ to $51^{\circ}$. The slope area is from northeast to northwest sides and the altitude range of distribution site is between 220 m and 533 m. The vascular plants in the quadrate where Lindera sericea were studied were identified as a total of 72 taxa; 37 families, 54 genera, 66 species, 5 variants and 1 forma. Among the floristics specific species, IV grade species was Lindera sericea and III grade species were Stewartia pseudocamellia and Acer palmatum. Korean endemic species were Stewartia pseudocamellia and Carex okamotoi. As for the vegetation group, Quercus mongolica and Q. serratak - Lindera sericea, Styrax japonicus populations were found in Mt. Mudeung area where Lindera sericea appeared, Stewartia pseudocamellia-Lindera sericea and Sasa borealis populations were found in Mt. Cheonbong areas, Carpinus laxiflora - Lindera sericea and Sasa borealis populations were found in Mt. Chogye area, and Stewartia pseudocamellia-Lindera sericea and Sasa borealis populations were found in Songgwangsa area. A total number of 662 Lindera sericea individuals were examined. The number of trees with 1 trunk including younger individuals was 353 (53.32%), and the number of trees with 2 to 5 stems was 270 (40.79%). The number of trees with the greatest number of sprouts was 27. Of 662 trees in total, the total number of sprouts was 1,198. Among these, 699 trees (58.34%) were between 50 cm and 150 cm in height. The tallest tree was 585 cm. The most common root-collar diameter of sprouts (992, 82.81%) was under 1 cm, followed by the sprouts with collar diameter from 1.0 to 1.5 cm(156, 13.2%). Among them, the largest root-collar diameter was 3.2 cm. This Lindera sericea specimen had the tallest trunk (565 cm) which was torn lengthwise on one side. Its root and breast parts were decayed by 50% and 25 respectively. Some branches of the three trunks that were more than 4 m in length were dead in the apical portion. Therefore, it is proposed that the Korean Lindera sericea maintains an apical dominance tree type while showing morphological adaptation as a typical shrub because it autonomously decays some branches and trunks over a certain height while increasing the number of its sprouts.

• Korean Journal of Environment and Ecology
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• v.24 no.2
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• pp.147-156
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• 2010

This study was conducted from April, 2002 to March 2006, using three urban streams(Gap Stream, Yudeung Stream and Daejeon Stream) in Daejeon Metropolitan City. 12,027 individual birds summed by the peak count in 126 species, 34 families, and 13 orders were observed from three stream sites. Dominant species were of Anas poecilorhyncha, Anas crecca, Columba livia, Passer montanus, and Egretta garzetta(in that order). The groups of birds were classified into six types. The most frequent group were the arbor birds(54 species), while the smallest group was the diving ducks(7 species). As for the number of individuals, the shrub bird group had 721 individuals while the dabbling ducks observed had 4,974 individuals. Regarding the distribution of birds appeareing in each stream, 14,885 individual numbers in 114 species were observed at Gap Stream, 6,642 individuals in 90 species at Yudeung Stream and 4,202 individuals in 69 species at Daejeon Stream. Various indices of the birds were analyzed with respects to the similarities between streams. Gap Stream had similar characteristics to Yudeung Stream, and the latter was similar to Daejeon Stream. However, Gap Stream and Daejeon Stream showed different characteristics. The dominance index of each section was calculated using ten dominant bird species top-down. Subsequently, the birds and their preferred environment were analyzed. The results showed that shrub birds and arbor birds preferred the upper stream of every stream, while herons and dabbling ducks inhabited the midstream. Dabbling ducks and some diving ducks appeared downstream.