• Korean journal of applied entomology
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• v.15 no.3 s.28
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• pp.111-126
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• 1976

Regional differences in economic importance of the four species of rice leafhoppers, viz., Laodelphax striatellus, Nephotettix cincticeps, Nilaparvata Iugens and Sogatella furcifera, were analyzed and discussed based on population surveys conducted in Suweon and in southern and south-western coastal areas. The economic importance of L. striatellus and N. cincticeps, which are found throughout the year in Korea, seems to be less in middle regions. This is believed due to effective natural control through severe winter climate, cultural practices in rice and barley growing, and natural enemies such as spiders. However, the economic importance of these two species is significantly greater in southern regions with a less severe winter climate, and where cultural practices in rice and barley favour synchronization between the life cycles of insects and the seasonal succession of host plants. with regard to N. lugens and S. furcifera, which cannot overwinter in Korea, initial populations are the result of long distance migration across the East China Sea. Weather elements related to their migration result in more abundant immigrants of these two species in southern than in middle regions. Thus, different policies are needed for the integrated control of rice leafhoppers in middle and southern Korea.

• Korean Journal of Ichthyology
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• v.19 no.4
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• pp.378-386
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• 2007

To study the composition of the developmental stages of Maurolicus japonicus eggs distributed in the western Korea Strait, we investigated the water temperature, salinity, eggs and larvae in December 2002. The Korea Strait Bottom Cold Water (KSBCW) lower than $10^{\circ}C$ was found in off the Ulsan and Busan where M. japonicus eggs were the most abundant. The composition of the developmental stages of M. japonicus eggs at each station were composed of 37.7~89.5% in the first stage, 8.5~37.8% in the middle stage and 0.0~24.7% in the last stage respectively. In the southern area where the KSBCW appeared, the first stage eggs occupied 73.3~89.5%. The high percentage of the first stage eggs indicated that the eggs should be transported by the cold water lower than $10^{\circ}C$ from the Ulleung Basin in the East Sea. In the northern area where the KSBCW was not found, the first, middle and last stage eggs were composed of 37.5%, 37.8% and 24.7% respectively. The ratios of middle and last stage eggs were much higher than those in the southern area with the KSBCW, which implies that the eggs are recruited into the northern area from the southern area with the KSBCW by the Tsushima Warm Current. The pre-larvae found only in the middle and northern part of the study area would be hatched during the transport of eggs from the southern area with the KSBCW by the Tsushima Warm Current.

• 한국해양학회지
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• v.27 no.2
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• pp.164-172
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• 1992

This study was carried out to investigate the benthic polchaete community in the southern area of Kyeonggi Bay, Korea. The species composition was examined in Asan Bay in 1985, the coastal area near Yibug in 1987, the area between Daeranjido and Asan Bay for 1988-1989, and the offshore south of Deogjeogdo in 1992. Polychaetes, the dominant faunal group occupying 57.4% in total density, comprised a total of 124 species with a mean density of 211 indiv.m/SUP -2/. The dominant polychaete was Prionospio sp. (28.8%), followed by Nephtys polybranchia (6.0%), Tharyx sp. (4.8%) Stermaspis scutata (4.4%), Lumbrineris longifolia (3.9%). The Number of species and density were higher in the coastal area near Yibug, Asan Bay and the mouth of Namyang Bay, while lower in the channels of offshore region. The cluster analysis revealed that the study area could be divided into 5 regions, which were distributed serially along the coast from Asan Bay to open sea. Each region sustained its specific Bay, Stermaspis-Heteromastus assemblage from Asan Bay to Daeranjido, Hemipodus assemblage in the channels of offshore, Lumbrineris assemblage on the coastal area o Yibug and Prionospio assemblage in the coastal area south of Yibug. Tharyx-Chone assemblage had the highest species number of 75 spp. and Prionospio assemblage had the highest density of 3,695 indiv.m/SUP -2/ due to the predominance of prionospio sp.. Hemipodus assemblage with the lowest density occupied the largest area in offshore region. The southern Kyeonggi Bay showed higher species number and lower density than the northern Kyeonggi Bay. But the dominant Polychaetes were similar between the southern Bay and the channel regions of the northern Bay.

• Journal of the Korean Society for Marine Environment & Energy
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• v.3 no.1
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• pp.52-61
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• 2000

The field surveys and the seawater analyses were conducted over the southern waters of Cheju island every month from July 1997 to June 1988. The distributions of dissolved inorganic nitrogen(DIN), dissolved inorganic phosphorus(DIP), chemical oxygen demand(COD) and dissolved oxygen(DO) in the southern water area of Cheju island were simulated and reproduced by an ecosystem model. In order to estimate the environmental capacity of the southern coastal area of Cheju island, the simulations for predicting the situation of unfavorable environment in which marine water quality might not be satisfied with Korean standards were performed with an ecosystem model by controlling quantitatively the pollution loads of discharge sources including streams flowing into the sea. The more the loads of 4 major pollution sources flowing into model region increase, the more evident appear the increases of COD, DIN and DIP concentrations around the water areas adjacent to pollution sources. In case the pollution loads of all 4 discharge sources including streams become 3 times as high as the present loads, the concentration of DIN at near-shore waters appears to be increased to about 14.5mmol/m³(=0.20mg/ℓ) which is the third class criterion of Korean standards for marine water quality. In case of 10 times as high as the present loads, COD at near-shore waters appears to be increased to about 1.0mg/ℓ which is the first class criterion of Korean standards. In case of 20 times as high as the present loads, DIP at near-shore waters appears to be increased to about 0.50mmol/m³(=0.015mg/ℓ) which is the second class criterion of Korean standards.

• Journal of the Mineralogical Society of Korea
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• v.23 no.1
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• pp.15-23
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• 2010

The absolute clay mineral compositions and regional distribution of the 131 bulk marine surface sediments around the Jeju Island was compared to their relative compositions and distribution using quantitative X-ray diffraction analysis. Average absolute clay mineral composition is illite 15.3% (0.5~40.5%), chlorite 2.6% (0~7.9%), and kaolinite 1% (0~5.6%). Total contents of the clay minerals are very high in the South Sea of Korea, northwestern part and southern offshore of Jeju Island. The average relative composition is illite 70.9% (16.7~89%), chlorite 21.5% (8.4~68.5%), and kaolinite 7.6% (0~29.3%). Relative illite contents are high in the northwestern and southeastern part of study area, and southern part of Jeju Island. Chlorite contents are high in the eastern part of study area and western part of Jeju Island. Kaolinite contents are high in the western and southern part of Jeju Island, and southern offshore of Jeju Isand. Absolute Distribution patterns are very similar to those of fine-grained (from clay to silt) sediment, whereas relative distribution patterns do not show any relationship with those of fine-grained sediment.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.8 no.2
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• pp.138-150
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• 2003

In the mid-west coast of Korea where Mankyung and Dongjin rivers discharge fresh water, Saemangeum tidal dyke of 33 km long is under construction to reclaim the very shallow estuary region of 41,000ha. Main source of freshwater in this coastal area is Keum River locating closely north of the dyke. At present, the dyke connected with Gogunsan-Gundo separates this area into three regions; northwestern, southwestern and eastern (Saemangeum) region of the dyke, and the water in Saemangeum region is exchanged through one gap in the northern dyke and two gaps in the southern dyke. We have observed distributions and structures of temperature and salinity to examine the summer circulation related with low-salinity water in this coastal area in 1998 and 1999. In the surface layer off the northern dyke a tongue-like distribution of low-salinity extends 60 km long from Keum River estuary mouth to the northwest, forming plume front bounded by offshore water. In the inner region of Saemangeum dykes salinity distributions show that two river waters are merged together and the low salinity water is deflected toward northern gap of the dyke. In the surface layer off the southern dyke we observed small tongue-like distribution of another low-salinity water extending to the north from Gomso Bay. Based on the analysis of distributions of low-salinity water and frontal structures, we can suggest an anticlockwise circulation of coastal water around the dyke, composed by the estuarine water outgoing from the inner region of the dyke through the northern dyke's gap and the inflow through two gaps of southern dyke from offshore. After completing the dyke construction, this coastal circulation around the dyke will be, however, changed because fresh water discharge of Mankyung and Dongjin rivers will be routed artificially and directly into the area offshore of the southern dyke.

• Journal of the Korea Convergence Society
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• v.10 no.2
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• pp.133-139
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• 2019

A Convergence Research Study of Southern Fujian Region in China during the Song Dynasty analyzing the Export of Ceramics During the Song Dynasty in China ceramics made in the Southern Fujian (also known as Minnan) region were exported to different countries in Southeast Asia including the Philippines, Thailand and more. They were even exported to Korea, Japan and through trade they traveled as far as Africa. Ceramics was one of the three main sea route export item of China at the time and there were active commercial trading between Korea as well as other countries, enabling ceramics to develop rapidly. The harmonious reciprocal relationship between the geographical, political, cultural, economical characteristics of Southern Fujian enabled a unique type of celadon ware widely recognized to develop. Ceramics of this region is one of a kind in terms of history when we relate it to research on integrating different elements. It suggests a unique convergence of culture when we study its forms and its industrial characteristics. The study attempts to analyze the influence of geography, politics, economy and culture on the different phenomena found in ceramics. Different paradigms associated with changes of environment reflect on continued development in the field of ceramics.

• Fisheries and Aquatic Sciences
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• v.9 no.2
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• pp.83-90
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• 2006

This paper provides descriptions and illustrations of two hippolytid shrimps, Eualus macilentus ($Kr{\phi}yer$, 1841) and E. leptognathus (Stimpson, 1860). This is the first record of E. macilentus collected in Korean waters; it was found in the East Sea at a depth of 300 m. Eualus leptognathus has been collected previously from various locations in southern and eastern Korea, but no detailed description has been reported. This study provides a key to the six species of Eualus in Korean waters.

• Animal Systematics, Evolution and Diversity
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• v.27 no.3
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• pp.239-245
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• 2011

We describe and illustrate two pontoniine shrimps, Cuapetes grandis and Periclimenes ornatus, for the first time in Korea. C. grandis was collected in an artifical reef of Dadae, Geojedo Island by SCUBA diving in 15-20 m depth. This species was found in an oyster within an artificial reef and appeared to be free-living. P. ornatus was collected from Seongsanpo, Jejudo Island by SCUBA diving in 10 m depth. This species had a symbiotic relationship with sea anemone. This record extends their previously known range from southern Japan to the Korean peninsula and the number of known pontoniine species in Korea to four.

• 한국석유지질학회:학술대회논문집
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• spring
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• pp.56-65
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• 1998

Methane hydrate is ice-like solid compound consisting of mainly methane and water, and is stable under specific low temperature and high pressure conditions (HSZ : methane hydrate stability zone) that occurs in permafrost regions and in the ocean floor sediments. Geophysical survey was implemented in the southern area of the East Sea, and the HSZ of the study area is determined by the temperature, pressure and local heat flow obtained from the survey and well data. In the study area, methane hydrates could exist in the sediments below the water depths of about $300{\cal}m$, and the base of HSZ is about 600m beneath the seafloor. The acoustically blanking zones in the sediment and phenomena of gas seepage were detected from the seismic section. These sediments have the sufficient physical condition for the formation of methane hydrate. The temperature and pressure conditions were experimentally measured for the dissociation of methane and propane hydrates in Pure water. Equilibrium conditions of methane and propane hydrates were obtained in the pressure range up to 19050Kpa and 401.3Kpa. Under same temperature condition, propane hydrate was dissociated at lower pressure than that of methane hydrate.