• 한국양식학회지
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• 제12권3호
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• pp.193-196
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• 1999

In order to obtain the basic data for the effective seed production of Ureshis unicinctus sediment preference, burrow shape and burrowing depth in sediment were investigated in the laboratory. The highest valus in both sediment preference and burrowing rate of U. unicinctus were shown at fine and (0.11~0.50mm in the mean diameter). U. unicinctus made various types of burrows, such as J, L, S and U shapes. Generally only one individual inhabits in burrow with head-up.

• 한국양식학회지
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• 제16권1호
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• pp.24-30
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• 2003

수정된 난은 분리침성란으로 저면에 침하하였으나, 해수의 유동에 의하여 쉽게 부상하는 성질이 있었다. 또 난의 모양은 완전한 구형으로 구경은 평균 150 $\mu\textrm{m}$ 정도였다. 각 발생 단계의 소요시간을 보면 8세포기까지 1.9시간, 상실기까지 7.9시간, 낭배기까지 27시간이 소요되었다. 담륜자 유생까지의 발생소요시간은 68시간이었는데 이 기간에는 섭이를 위해 활발하게 유영운동을 하였으며, 이때 유생의 체장은 평균63 $\mu\textrm{m}$였다. 평균체장 163 $\mu\textrm{m}$인 담륜자 유생이 7체절기로 성장하는데는 18일이 걸렸고, 13체절기까지의 소요시간은 29일었으며, 이 시기부터는 저면에서 연동운동에 의한 이동이 관찰되었다. 그리고 32일 경과시에는 평균체장은 768 $\mu\textrm{m}$인 치충으로 저질에 굴을 파고 잠입하였다. 60일 후 개불 치충의 평균체장은 1,108 $\mu\textrm{m}$였고, 90일 후에는 1.835 $\mu\textrm{m}$였으며, 체색은 투명하였다. 또한 120일 이후에는 평균체장이 3.7cm로 성장하였고, 체색은 적황색이었으며, 입 주위에 강모가 생성되어 완전한 성체의 모습을 갖추었다. 사육일수와 체장에 관한 상대성장식은 BL=0.2097 $e^{0.048}$4RD/ ($r^2$=0.9299)이었고(Fig. 2), 체장과 체폭의 상대성장식은 BB=0.2033BL-383.21($r^2$=0.9518)이었다. 저질선택성 실험개시 30일 경과 후, 펄에서 31마리, 조개껍질과 모래의 혼합구에서 23마리, 펄과 모래의 혼합구에서 21마리, 펄과 모래와 조개껍질의 혼합구에서 32마리가 관찰된 것에 반해 모래구에서는 한 마리도 관찰되지 않았다. 또한 개불의 잠입깊이 실험 결과, 2.5~5cm, 5~7.5cm구간에서 각각 10마리가 관찰되었다.

• 한국수산과학회지
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• 제30권4호
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• pp.634-639
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• 1997

한국산 갯지렁이류 중에서 산업적으로 가장 중요한 청충의 양식기법 개발에 관한 기초자료를 얻기 위하여, 청충의 서식생태에 관하여 조사한 결과는 다음과 같다. 1. 청충은 입경이 0.10mm 이하인 저질에서 가장 좋은 일간 성장률과 생존율을 보였다. 2. 유리 수조 실험 결과, 청충이 저질 속에 잠입하여 만든 굴의 형태는 J형, L형, O형, S형, Y형 및 I형 등이 었고, 한 개의 굴에 한 개체가 서식하는 것이 일반적이었으며, 배설시 청충의 체위는 굴 속에서 두부와 미부를서로 반전하여 항문을 굴밖의 저질 표면에 노출 시킨채로 배설하였다. 3. 청충이 저질속에 잠입하는 깊이는 10cm 전후의 저질이며, 먹이를 먹기 위해서는 굴 밖으로 몸체를 완전히 이탈하여 이동하였다.

• 한국환경과학회지
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• 제11권9호
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• pp.961-969
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• 2002

This study was performed : 1) to establish the experimental analysis conditions for the sorption and desorption of toxic organic contaminants to/from the activated sludge, sediment, and clay, and 2) to determine the sorption and desorption equilibrium coefficients of some representative halogenated aliphatic compounds. Through the preliminary sorption test using Azo dye, a setting of quantitative experimental conditions to determine the sorption and desorption characteristics was decided as follows; equilibration time of 180 minutes, centrifuge for 15 minutes at 5000$\times$g, and 500mg/$\ell$ of TOC concentration. The sorption and desorption characteristics of halogenated aliphatic compounds onto activated sludge, sediment and clay could be described very well using the Freundlich isotherm. The preference of the average sorption capacity of the overall compounds showed in the sequence sediment 0.26mg/g, clay 0.23mg/g, and activated sludge 0.11 mg/g. The desorption rate of the sorbed compounds onto activated sludge, sediment and clay was approximately 89.8%, 35.3%, and 66.4%, respectively.

• 한국환경과학회지
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• 제3권1호
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• pp.65-76
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• 1994

자연호소의 혐기성 저질을 특정한 chlorophenol(CP)에 적응시킨 후 다른 구조물 가진 CP에 대한 탈염소 특성을 검토하였다. CP에 노출되지 않는 혐기성 저질에서는 mono-CP의 경우 ortho > meta > para-염소의 손으로 di-CP의 경우는 ortho > par > meta- 염소의 순서로 짧은 지체기를 거친 후 탈염소가 발생하였다. Mono-CP 중 2-CP에 적응된 저질은 4-CP와 3,4DCP를 제외하고, 3-CP에 적응시킨 저질은 4-CP를 제외한 모든 시험물질에 대하여 지체기 없이 탈염소 특성을 나타내었다. DCP에 적응된 모든 저질은 2-CP, 2,3,-, 2,4-, and 3,4-DCP를 지체기 없이 탈염소가 발생하지 않았다. 이 결과에서 볼 때 mono-와 di-CP를 탈염소시키는 혐기성 미생물의 종류가 다양함을 알 수 있다.

• 한국식품영양과학회지
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• 제27권6호
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• pp.1100-1104
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• 1998

The preference test of cowpea mook(gel prepared with air-dried sediment of cowpea) indicated that the optimum concentration and heating temperature for mook-making were 8% at 95$^{\circ}C$ or 9% at 90$^{\circ}$and 95$^{\circ}C$ with continuous heating method(A), and 8% at 85$^{\circ}C$ or 7% at 9$0^{\circ}C$ with instantaneous heating method(B). Among the samples the mook made from 9% at 95$^{\circ}C$ with the method A was the most preferable. The degree of increase in hardness of mook prepared by the method B stored at 6$^{\circ}C$ for 8hr was much slower than that by the method A. the preference test of the mook stored at 6$^{\circ}C$ for 1 day revealed that the mook by the method A with 8%(95$^{\circ}C$) and by the method B with 7 and 8% (85$^{\circ}C$) were not significantly different.

• 한국수자원학회논문집
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• 제41권4호
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• pp.365-377
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• 2008

본 논문에서는 다기준 의사결정 방법의 하나인 PROMETHEE(Preference Ranking Organization METHod for Enrichment Evaluations)를 적용하여 도시유역내 소유역간의 상대적 침수위험도를 산정하였다. 이를 위해 도시유역의 침수에 영향을 미치는 인자를 선정하여 이를 PROMETHEE 적용을 위한 평가기준으로 활용하였다. 침수발생에 영향을 미치는 인자로는 유역의 평균고도, 평균경사, 관밀도, 인구수, 단위면적당 유사발생량으로 선정하였다. 선정된 인자를 바탕으로 PROMETHEE를 적용하여 산정된 소유역간 상대적 침수위험도를 '98년 침수실적 결과와 유사발생에 따른 상대적 침수위험도와 비교 분석하였다. 유사발생량만을 근거로 한 침수위험도에 비해 다양한 인자를 고려하여 산정된 소유역간 침수위험도가 '98년 침수실적 결과와 더 일치하는 것으로 나타났다. 본 논문에서 적용된 PROMETHEE에 의한 평가방법은 침수 예상지역의 사전 예방을 위한 정비 사업 계획 추진에 있어서 우선순위에 대한 방향을 결정하는데 있어서 기초자료가 될 수 있을 것이다.

• 한국수산과학회지
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• 제37권6호
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• pp.469-477
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• 2004

This study examined distributional patterns of Asterias amurensis in Tongyeong, the central South Sea of Korea. The density of the sea star was estimated at 10 chosen sites in the inner and the outer parts of the Tongyeong coast from December 2000. The mean density of the species in this area was $2.4ind./m^{2}$. The seasonal surveys conducted at 3 arbitrary chosen sites (i.e., sea cage, reef and soft sediment) also showed that the abundance of the species at the sea cage site $(density:\;3.6\;ind./m^{2};\;biomass:\;250.7\;gwwt/m^{2})$ was significantly higher than at the reef site $(density:\;1.7\;ind./m^{2};\;biomass:\;63.5\;gwwt/m^{2})$ and the soft sediment site $(density:\;0.4\;ind./m^{2};\;biomass:\;18.9\;gwwt/m^{2})$. Densities were higher at sea cages areas than at reefs and soft bottom sites. At sea cage site, A. amurensis population exhibited a strong aggregated distributional pattern. In contrast, at reef and soft bottom sites, A. amurensis population showed a random distributional pattern. The spatial difference in prey species and its abundance was the primary factor determining the spatial heterogeneity of the sea star in its behavior characteristics. Experiments on the feeding preference indicated that A. amurensis had a strong selectivity on its prey, but this selectivity varied between populations living in different sites. In particular, A. amurensis populations at the reef site showed a strong selectivity on various sessile and mobile animals living in reef areas, suggesting that these animal groups may play a role as "windows for the survival of A. amurensis". These results suggest that the distribution of A. amurensis in Tongyeong is closely associated with abundance of prey species and the bottom composition.

• Mycobiology
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• 제50권5호
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• pp.326-344
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• 2022

The fungal-like family Saprolegniaceae (Oomycota), also called "water mold," includes mostly aquatic saprophytes as well as notorious aquatic animal pathogens. Most studies on Saprolegniaceae have been biased toward pathogenic species that are important to aquaculture rather than saprotrophic species, despite the latter's crucial roles in carbon cycling of freshwater ecosystems. Few attempts have been made to study the diversity and ecology of Saprolegniaceae; thus, their ecological role is not well-known. During a survey of oomycetes between 2016 and 2021, we investigated the diversity and distribution of culturable Saprolegniaceae species in freshwater ecosystems of Korea. In the present study, members of Saprolegniaceae were isolated and identified at species level based on their cultural, morphological, and molecular phylogenetic analyses. Furthermore, substrate preference and seasonal dynamics for each were examined. Most of the species were previously reported as animal pathogens; however, in the present study, they were often isolated from other freshwater substrates, such as plant debris, algae, water, and soil sediment. The relative abundance of Saprolegniaceae was higher in the cold to cool season than that in the warm to hot season of Korea. This study enhances our understanding of the diversity and ecological attributes of Saprolegniaceae in freshwater ecosystems.

• Ocean and Polar Research
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• 제27권3호
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• pp.299-309
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• 2005

The community structure of meiobenthos was studied in the sediment of Kongfjorden, Spitsbergen of Svalbard Island in the Arctic Sea. Samples of meiobenthos were collected in August, 2003. Meiobenthic organisms were collected by SCUBA and van veen grab or acryl sub-corers 34mm in internal diameter, and were taken from upper sediment to a depth of 3cm at each station. A total of 26 meiofaunal groups were found in the sediment of Spitsbergen in Svalbard Island. Nematodes were the most dominant faunal group. Sarcomastigophorans, benthic harpacticoids, and nauplius larvae of crustaceans, were also important components of the meiobenthic community of Kongsfjorden. All of these low faunal groups were comprised of more than 90% of total meiobenthos at every station. The total density of meiobenthos at each station was highest at station MeG 6 $(3,583{\pm}1,137inds./10cm^2)$, and lowest at station $MeG9(28{\pm}1inds./10cm^2)$. Meiobenthos in general showed the highest density in the upper 1cm layer. This may be associated with food and oxygen supply to subsurface. Harpacticoids showed extreme preference at the surface and little presence in layers deeper than 2cm. These animals may be less resistant to oxygen deficiency, and nauplius also showed the same trend. However, in St. MeG 8 and 9, meiobenthos were dense at depths of more than 0-1cm, at especially at depths of 2-3m because of relatively easy penetration of oxygen. Based on the results of cluster analysis, three meiobenthos assemblages were distinguished: one was in the outer and two were in the inner fjord. Station SCU 5 was grouped with the meiobenthos assemblage located in the outer fjord. The outer ford community was characterised by : 1) a relatively low mean number of meiobenthos taxa, 2) a relatively high density of harpacticods and nauplius. One of the inner ford communities (a group of four nation: MeG 2, 3, 8, 9) was in the proximity of the glaciers. Specifically, it was characterised by : 1) a low mean number of meiobenthos taxa, 2) a low density. The other inner ford community was characterised by both a high density and great mean number of meiofaunal taxa.