• 한국해양학회지
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• v.24 no.1
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• pp.15-28
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• 1989

A study on quantitative phytoplankton samples, hydrographic conditions (temperature, salinity, dissolved oxygen), and nutrients has been performed in the southern waters of the Korean East Sea in early spring. Phytoplankton community showed close correlation with hydrographic conditions. This study area could be divided into three phytohydrographic regions; 1) East Korean Warm Water Region (a branch of Tsushima Current), 2) North Korean Cold Water Region, and 3) offshore water region not affected by other two water regions. Vertical distribution of phytoplankton is dependent upon stability of water column and nutrient concentration. Nutrient concentration shows characteristic distribution according to water masses. N/P ratio of ca. 3 in surface layer indicates that nitrogen is the major limiting nutrient in this area. N/P removal ratio was 12.54 ($r^2$ = 0.96), consistent with the Redified ratio. Primary nitrite maxima at the nitracline depths are thought to be formed by phytoplankton exudation. Secondary nitrite maximum was observed in coastal area with dissolved oxygen content of >5.2 ml/l much higher than <0.25 ml/l in other areas. The mechanism of secondary maximum is different from that of other regions, and whether it may be due to in situ degradation of organic matter by bacterial activity is still open to discuss.

• Korean Journal of Remote Sensing
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• v.14 no.1
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• pp.37-52
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• 1998

The NSCAT(NASA Scatterometer) carried by the japanese Advanced Earth Observing Satellite(ADEOS) was the first high resolution(25 km) device for the direct wind measurement over the ocean. Even it was ceased to operate in lune of 1977 because of the power failure, it gave the first opportunity to the marine meteorologists to study the direct measured ocean wind during its 9 months of operation, especially around Korea. This study is to show monthly mean ocean wind and wind stress curl fields around Korea from January, 1997 to June, 1997. Mean ocean winds in January are predominantly northwesterly and the strongest wind(12 m/s) is found near Vladivostok. The winds in the western East Sea are strongly inf1uenced by the mountain range in Korea and these topographically influenced winds make about five times larger wind stress curl fields than previous estimates based on the weather maps. The calculation of Sverdrup transport in the East Sea shows the possibility of the directional change of the East Korean Cold Current from southward to northward direction caused by the winter wind. The downwelling area near North Korea has maximum estimated speed of 45 m in january and this wind induced downwelling makes good condition for the formation of Intermediate East Sea Water together with vigorous mixing by the strong wind.

• Atmosphere
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• v.15 no.2
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• pp.75-90
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• 2005

This study examines the impacts of land cover changes on the East Asia summer monsoon with the National Center for Atmospheric Research Regional Climate Model (NCAR RegCM2), coupled with Biosphere Atmosphere Transfer Scheme (BATS). To assess the goals, two types of land cover maps were used in the simulation of summer climate. One type was NCAR land cover map (CTL) and the other was current land cover map derived from satellite data (land cover: LCV). Warm and cold surface temperature biases of $1-3^{\circ}C$ occurred over central China and Mongolia in CTL. The model produced excessive precipitation over northern land area but less over southern ocean of the model domain. Changes of biophysical parameters, such as albedo, minimum stomatal resistance and roughness length, due to the land cover changes resulted in the alteration of land-atmosphere interactions. Latent heat flux and wind speed in LCV increased noticeably over central China where deciduous broad leaf trees have been replaced by mixed farm and irrigated crop. As a result, the systematic warm biases over central China were greatly reduced in LCV. Strong cooling of central China decreased pressure gradient between East Asian continent and Pacific Ocean. The decreased pressure gradient suppressed the northward transport of moisture from south China and South China Sea. These changes reduced not only the excessive precipitation over north China and Mongolia but also less precipitation over south China. However, the land cover changes increased the precipitation over the Korean Peninsula and the Japan Islands, especially in July and August.

• Cross-Cultural Studies
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• v.44
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• pp.373-391
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• 2016

Since the 2000's, interest toward Africa in Korea has increased rapidly. Korea's interest in Africa began in the second half of the 1960's. However, this interest in the 1960's was motivated by political and diplomatic necessity at the time rather than the needs of indigenous groups in Africa. Korea had to oppose North Korea's diplomatic expansion in Africa to gain the support of international organizations like the United Nations. This interest in Africa motivated by diplomatic needs vanished quickly after the end of the cold war in the 1990's. Authentic Korean interest in Africa began to emerge in the 2000's. Korea's rising international status based on economic development led to a natural interest in Africa, which was the last frontier on earth. As a result, African studies in Korea increased significantly after 2010. The increase in the number of theses, articles and books was remarkable from 2010-2016, in comparison with 1957-2010. In spite of the increase in the quantity of thesis, articles, and books, the problem with Korea's African studies is above all, its preponderance. Over 75% of thesis and 70% of articles are concentrated in the domain of politics and economics. This reflects the fact that Korea's interest in Africa is based on short term political and economic interest, indicating that Korea's African studies did not deviate from the rudimentary phase in its quantity and quality. Another problem with Korea's African studies is the lack of integration of different types of research. African studies in Korea has three components, government funded research centers, university laboratories and individual researchers. The government funded research centers focus on the overview of African nations and their political and economic information. University laboratories mainly perform research on the theoretical aspects of politics, economics, human sciences and culture in Africa. Individual researchers are concerned with various categories. However, these three groups have failed to achieve a synergic effect on African studies in Korea and most of the research on Africa does not extend beyond each academic area. To overcome this problem, first of all, a live exchange may be necessary between domestic researchers.

• Journal of the Korean earth science society
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• v.41 no.5
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• pp.504-519
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• 2020

Oceanic fronts, which are areas where sea water with different properties meet in the ocean, play an important role in controlling weather and climate change through air-sea interactions and marine dynamics such as heat and momentum exchange and processes by which properties of sea water are mixed. Such oceanic fronts have long been described in secondary school textbooks with the term 'Jokyung water zone (JWC hereafter) or oceanic front', meaning areas where the different currents met, and were related to fishing grounds in the East Sea. However, higher education materials and marine scientists have not used this term for the past few decades; therefore, the appropriateness of the term needs to be analyzed to remove any misconceptions presented. This study analyzed 11 secondary school textbooks (5 middle school textbooks and 6 high school textbooks) based on the revised 2015 curriculum. A survey of 30 secondary school science teachers was also conducted to analyze their awareness of the problems. An analysis of the textbook contents related to the JWC and fishing grounds found several errors and misconceptions that did not correspond with scientific facts. Although the textbooks mainly uses the concept of the JWC to represent the meeting of cold and warm currents, it would be reasonable to replace it with the more comprehensive term 'oceanic front', which would indicate an area where different properties of sea water-such as its temperature, salinity, density, and velocity-interact. In the textbooks, seasonal changes in the fishing grounds are linked to seasonal changes in the North Korean Cold Current (NKCC), which moves southwards in winter and northwards in summer; this is the complete opposite of previous scientific knowledge, which describes it strengthening in summer. Fishing grounds are not limited to narrow coastal zones; they are widespread throughout the East Sea. The results of the survey of teachers demonstrated that this misconception has persisted for decades. This study emphasized the importance of using scientific knowledge to correct misconceptions related to the JWC, fishing grounds, and the NKCC and addressed the importance of transferring procedures to the curriculum. It is expected that the conclusions of this study will have an important role on textbook revision and teacher education in the future.

• Korean Journal of Ecology and Environment
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• v.51 no.1
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• pp.71-85
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• 2018

A recent topic of interest within ecology is ecosystem services that are importantly connected with biodiversity. Biodiversity is a fundamental component of ecological studies and has been the subject of many studies worldwide. However, studies on the diversity and distribution of freshwater fish were not undertaken in earnest until 2000, and the number of internationally available studies is therefore still limited. In this study, we used data from "The Survey and Evaluation of Aquatic Ecosystem Health (hereafter SEAEH)" within the framework of which whole water systems on the Korean peninsula are annually monitored to investigate and determine the current status of the diversity and distribution of freshwater fish, as well as to elucidate major factors impacting freshwater fish. A total of 130 species from 28 families were identified at around 953 sites in the SEAEH investigation of 2014. The species Zacco platypus (relative abundance: 28.2%) and Z. koreanus (19.3%) were identified as the most abundant species on the Korean peninsula, and besides these 20 endangered species, 51 endemic species and 4 exotic species were also collected. Highest (96 species) and lowest (72 species) diversity were identified in the Han River Watershed and the Yeongsan/Seomjin River Watershed, respectively. The mean endemic rate was 32.7%, which is higher than the previous rate determined in 1995. The exotic species Micropterus salmoides, Lepomis macrochirus and Carassius cuvieri were found in the whole river system except north Yeongdong, whereas Oreochromis niloticus occurred only at three sites due to the cold water temperatures in winter. Totally, 28 species were found to be translocated to different water systems not connected with known original habitats, most translocations occurring in the Nakdong River and the Yeongdong region. Among the translocated species, Opsariichthys uncirostris amurensis, and Erythroculter erythropterus were dominantly distributed in the mid- to lower reaches of Nakdong River where they may be harmful to the native fish assemblages due to their strong predation. The construction of weirs in connection with the "4 River Project" generated changes in fish assemblages before, during and after the project, resulting in altered habitat condition. Especially, a decrease in the number of endemic species and an increase in the abundance of lentic species were seen. Human-induced global warming will allow exotic species requiring high water temperatures to adapt to the environmental conditions of the Korean peninsula, which may enhance the diversity of native fishes and create changes in distribution. For the establishment of realistic and efficient management and protection strategies for Korean freshwater fish, SEAEH, which produces fundamental and quantitative data for Korean streams, is an important and necessary tool.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.4
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• pp.292-302
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• 2012

This paper reviews comparison analysis of current and latest application for stock identification methods of Todarodes pacificus, and the pros and cons of each method and consideration of how to compensate for each other. Todarodes pacificus which migrates wide areas in western North Pacific is important fishery resource ecologically and commercially. Todarodes pacificus is also considered as 'biological indicator' of ocean environmental changes. And changes in its short and long term catch and distribution area occur along with environmental changes. For example, while the catch of pollack, a cold water fish, has dramatically decreased until today after the climate regime shift in 1987/1988, the catch of Todarodes pacificus has been dramatically increased. Regarding the decrease in pollack catch, overfishing and climate changes were considered as the main causes, but there has been no definite reason until today. One of the reasons why there is no definite answer is related with no proper analysis about ecological and environmental aspects based on stock identification. Subpopulation is a group sharing the same gene pool through sexual reproduction process within limited boundaries having similar ecological characteristics. Each individual with same stock might be affected by different environment in temporal and spatial during the process of spawning, recruitment and then reproduction. Thereby, accurate stock analysis about the species can play an efficient alternative to comply with effective resource management and rapid changes. Four main stock analysis were applied to Todarodes pacificus: Morphologic Method, Ecological Method, Tagging Method, Genetic Method. Ecological method is studies for analysis of differences in spawning grounds by analysing the individual ecological change, distribution, migration status, parasitic state of parasite, kinds of parasite and parasite infection rate etc. Currently the method has been studying lively can identify the group in the similar environment. However It is difficult to know to identify the same genetic group in each other. Tagging Method is direct method. It can analyse cohort's migration, distribution and location of spawning, but it is very difficult to recapture tagged squids and hard to tag juveniles. Genetic method, which is for useful fishery resource stock analysis has provided the basic information regarding resource management study. Genetic method for stock analysis is determined according to markers' sensitivity and need to select high multiform of genetic markers. For stock identification, isozyme multiform has been used for genetic markers. Recently there is increase in use of makers with high range variability among DNA sequencing like mitochondria, microsatellite. Even the current morphologic method, tagging method and ecological method played important rolls through finding Todarodes pacificus' life cycle, migration route and changes in spawning grounds, it is still difficult to analyze the stock of Todarodes pacificus as those are distributed in difference seas. Lately, by taking advantages of each stock analysis method, more complicated method is being applied. If based on such analysis and genetic method for improvement are played, there will be much advance in management system for the resource fluctuation of Todarodes pacificus.