• Korean Journal of Fisheries and Aquatic Sciences
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• v.24 no.4
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• pp.237-247
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• 1991

To characterize the community structure and spatial distribution of phytoplankton, observations on seawater temperature, salinity, nutrients, primary productivity and abundance and species composition of phytoplankton were made in the polar front region and its neighborhood off the east coast of Korea in summer 1990. Among the 96 taxa identified, Rhizosolenia setigera and Thalassionema nitzschioides were the most dominant species. The assemblage at the surface and 50 m depth was quite different in the northern inshore part of the study area but similar in the southern and offshore part. Principal component analysis by the species abundance showed that the phytoplankton consisted of the communities representing the surface of the northern inshore part with the neritic-warm dinoflagellates, the Northern Korean Cold Water with the cold water diatoms and the southern and offshore part, which seems to represent the Eastern Korean Warm Water, with the warm water diatoms. At the frontal region, diatoms were mixed with warm and cold water species. Primary productivity and phytoplankton standing crops were higher at the front than the neighboring waters. Nutrients were markedly high at the Northern Korean Cold Water. Horizontal advection of the Northern Korean Cold Water accompanied by nutrient supply seems to contribute to the high phytoplankton biomass at the front.

• The Science & Technology
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• v.35 no.8 s.399
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• pp.43-66
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• 2002

[통치자의 과학기술 리더십] 정책조정자형 과학기술 리더십 전환시급, 체계적 보좌기초 목표달성체제 구축해야/ [국내 역대대통령의 과학기술 정책] 박정희대통령 과학기술 초석놓고 전두환 이어 김대중대통령 변화기 진입/[외국 역대대통치자의 과학기술 정책/미국] 역대 대통령 '과학기술은 국력' 인식, 레이건은 '스타워즈'로 소련붕괴 불러와/[외국 역대대통치자의 과학기술 정책/일본] 역대 총리 6명이 과학기술청 장관 출신, '나카소네수상' 원자력 선진국 기틀 마련/[외국 역대대통치자의 과학기술 정책/중국]'모택동' 국방기술 개발에 총력 핵탄 완성, '등소평' 과학기술은 제일의 생산력 강조/[외국 역대대통치자의 과학기술 정책/영ㆍ독ㆍ불ㆍ러]프랑스 - 과학기술 선진국 나폴레옹과 드골 초석, 러시아 - 레닌 이후 모든 통치자 科技 위해 정책 펴

• The Bimonthly Magazine for Agrochemicals and Plant Protection
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• v.11 no.1 s.94
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• pp.88-95
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• 1990

축산업에서 성패를 좌우하는 요인으로 빼놓을 수 없는 것 중의 하나는 가축의 먹이 공급원인 목초를 얼마만큼 잘 안정되게 생산해낼 수 있느냐 하는 것이다. 목초의 생산에는 지력과 작물자체의 생산력 뿐만 아니라 생산에 장애를 일으키는 병해충을 정확히 파악하여 그들에 의한 피해를 감소시키는 것도 매우 중요한 일이다. 목초의 해충은 발아당시의 해충, 줄기와 잎을 가해하는 해충, 토양해충, 채종시의 해충 등으로 구분할 수 있다. 우리나라에서는 목초의 잎과 줄기를 가해하는 멸강나방과 땅속에서 목초의 뿌리를 갉아먹어 피해를 주는 굼벵이(풍뎅이의 유충)가 주요 해충으로 알려져 있다. 멸강나방에 대해서는 이미 많은 연구결과가 발표되었으나 굼벵이에 대해서는 극히 미약한 연구만이 수행되어 이 해충에 대하여는 참고자료가 전무한 상태이다. 따라서 필자는 그동안의 연구결과 중 일부를 정리발표하여 굼벵이의 생태 및 방제연구에 기초자료를 제공함은 물론 축산농가에 도움을 주고자 한다.

• Journal of Ocean Engineering and Technology
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• v.26 no.1
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• pp.78-83
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• 2012

The abundant nutrients contained in deep seawater are delivered by natural upwellings from the deep sea to the surface sea. However, the natural upwelling phenomenon is limited to specific areas of the sea; in other areas, the thermocline separates the surface sea from the lower layer. Thus, the surface layer is often deficient in nutritive salts, causing the deterioration of its primary productivity and ultimately leading to an imbalance in the marine ecosystem. Without a consistent supply of nitrogenous nutritive salts, they are absorbed by phytoplankton, resulting in a considerable problem in primary productivity. To solve this issue, a floating type of artificial upwelling system is suggested to artificially pump up, distribute, and diffuse deep seawater containing rich nutritive salts. The key technologies for developing such a floating artificial upwelling system are a floating offshore structure with a large diameter riser, self-supplying energy system, density current generating system, method for estimating the emission and absorption of CO2, and way to evaluate the primary production variation. Strengthening the primary production of the sea by supplying deep seawater to the sea surface will result in a sea environment with abundant fishery resources.

• Korean Journal of Ecology and Environment
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• v.40 no.1
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• pp.61-71
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• 2007

The photosynthetic characteristics and primary production by phytoplankton in open waters of two wetlands (the Banwol and the Donghwa wetland) of Sihwa Constructed Wetland with different water chemistry were investigated to provide the information for the wetland management considering the water treatment efficiency. During the study period (from March to October, 2005) the primary productivity in open waters ranged from 481 to 11,275 mgC $m^{-2}$ $day^{-1}$, which is very high compared with the eutrophic level of 600mgC $m^{-2}$ $day^{-1}$. From the analysis of the photosynthesis-irradiance (P-I) model parameters, the photosynthetic characteristics may be affected by different concentration and ratio of nutrient (N and P) between two wetlands. Assimilation number (AN) was higher in the Donghwa wetland (average AN: 8.5gC $gChl^{-1}$ $hr^{-1}$) with high P and low N/P ratio than the Banwol wetland (average AN: 5.8gC $gChl^{-1}$ $hr^{-1}$) with high N and high N/P ratio. This result indicates that AN may be concerned with phosphorus than nitrogen and low NIP ratio. Positive correlation (R=0.81) was observed between the initial slope and AN, implying that AN was high in case of phytoplankton having more active photosynthesis ability under low light. On the other hand, maximum photosynthesis (Pmax) was related positively with chlorophyll a concentration showing correlation coefficient of 0.47. In this study, considering the high primary production through phytoplankton photosynthesis in open waters of Sihwa Constructed Wetland, the produced organic matter by phytoplankton may affect the water quality within wetland and its efficiency of water treatment. Also, the photosynthetic characteristics may be affected by different nutrient enrichment (especially phosphorus) of wetlands. This study suggests that the production by phytoplankton and its characteristics in open water of constructed wetland for water treatment should be considered to improve the removal efficiency of organic matter.

• Korean Journal of Soil Science and Fertilizer
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• v.19 no.3
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• pp.211-216
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• 1986

To establish a suitability grouping system of paddy soils for double or multiple cropping with rice which is intensively practiced in the southern parts of Korea, a few basic experiments were carried out for two years. The results are summarized as follows; 1. The potential productivities of the paddy soils which were tested without any fertilizer in the pots of subsoil samples by the double cropping of rice and other upland crops were resulted that the soils of "Moderately well drained" fine silty textured were the highest while the soils of "Poorly drained" sandy were the lowest, and the productivities could be clearly comparable according to the differences of soil conditions. 2. The decomposability of organic matter also was higher in the soils of "Moderately well drained" than the "Imperfectly drained". The coarse loamy and coarse silty textured soils were high in the upland condition and in the early stages of submerging while the fine loamy and fine silty textured soils were high at the late stage of submerging in the rates of organic matter decomposition. 3. The days to be reached to tillable condition after rainfall in fine loamy textured soils were about 5 days earlier than the clayey soils. The period of tillable condition of fine clayey soils with "Moderately well drained" was the longest and that of the fine loamy textured soils was the shortest. But the soils with "Imperfectly drained" were not clear among soil textural classes. 4. The lower the ground water table the higher was the productivity indices. The variation of ground water table in the medium textured soils was higher than the both of coarse and fine textured soils among "Moderately well drained". But it was observed the opposite in the soils of "Imperfectly drained".

• Journal of Korean Society for Geospatial Information Science
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• v.1 no.1 s.1
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• pp.153-158
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• 1993

The direction of land use for the subject district (Zuksan-myun, Anseong-gun, Kyeonggi-do) were analyzed as the basic model of new rural land management system connected to production and living. General land use planning was presented by land suitability classification which was applied to geographical information system(software ARC/INFO). The course of analysis of land suitability using the geographical information system were generalized and the results of analysis for paddy and upland fields and settlement were presented as 5 criteria of the suitability rank. It was found out that the analysis of land suitability is able to use as primary data of rural land use planning.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.23 no.6
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• pp.417-424
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• 1990

Effect of physical processes on the surface distributions of chlorophyll-a and nutrients was investigated in the southern sea of Korea during summer season. The northwestern area of Cheju Island had higher concentrations of the chlorophyll-a and nutrients than its southeastern area. A nutrient-rich patch was observed in the western area of Cheju Island and the northern area of $34^{\circ}N$ respectively. It seems that the patch in the western area of Cheju Island is formed by horizontal extension of the low-saline Coastal Water of China Contiental(CWCC), while the patch in the northern area of $34^{\circ}N$ by vertical mixing. Also, the high chlorophyll-a in the vicinity of Cheju Island appears to be ascribed to sufficient supply of nutrient from bottom water by coastal upwelling.

• 한국해양학회지
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• v.12 no.2
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• pp.57-66
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• 1977

Chlorophyll concentrations of phytoplankton were determined by 5 meters interval from surface to bottom layers in Yeongil Bay water of Korea, late October 1973. The contents of phytoplankton chlorophyll decreased outward from the inner part to the entrance of the Bay. It seemed to be caused by incoming land waters which are rich in nutrients. And vertical distribution pattern of the chlorophyll showed three layer zones in the middle and outer parts, and two layers in the inner part of the Bay. These phenomena suggest that there are two different water masses, the one is bottom cold water originated from offshore, the other is surface warm water. And they are mixed together in the middle layer The correlationship between the contents of chlorophyll a and chlorophyll c represented perfect positive relation with coefficient of r 0.999 from the extracted data. In general, chlorophyll a percent-content of total chlorophyll varied in the range of 14.64∼19.83% (mean value; 18.74%) and chlorophyll c content was about as much as four times compared with chlorophyll a content.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.29 no.5
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• pp.709-715
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• 1996

In order to estimate the carrying capacity of oyster culture ground in Kamak Bay, primary productivity was calculated using the ecosystem model. The allowable maximum oyster production, namely, the carrying capacity of Kamak Bay was estimated by using the annual phytoplankton production and conversion coefficient to oyster meat. On the environmental conditions of oyster culture period from lune, 1994 to March, 1995, phytoplankton production, the allowable maximum oyster production were estimated to be 181,594 tons of carbon and 287,033 tons of oyster meat, respectively. The allowable maximum oyster production was estimated to be 15,443 tons in the actual culture ground where oyster culture facilities are installed in Kamak Bay. In 1994 4,532 tons of actual oyster meat production was equivalent to ra. $29\%$ of carrying capacity, and in 1987 it was 14,592 tons equivalent to ca. $95\%$.