• 미생물학회지
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• 제40권3호
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• pp.244-247
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• 2004

이산화탄소 농도의 증가가 습지토양의 탈질세균 군집구조에 미치는 영향을 살펴보기 위하여 자연농도 (370 ppm)와 고농도 (740 ppm)의 이산화탄소조건의 습지생태계를 조성하여 110일 이상 배양한 후 토양 내 미생물 군집구조의 변화양상을 관찰하였다. 미생물 군집군조 분석은 탈질과정에 관여하는 효소중하나인 nitrite reductase의 유전자인 nirS 유전자를 대상으로 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) 분석기법을 이용하여 수행하였다. PCR 결과 모든 토양시료에서 nirS 유전자가 검출되었고, RFLP분석을 통해 자연농도의 이산화탄소조건에서 83개, 고농도 조건에서 95개의 phylotype을 획득하여 조성된 습지토양에서 탈질과정이 광범위하게 일어날 수 있음을 확인할 수 있었다. 두 경우 모두 두 종류 (type 1과 type 2)의 phylotype의 우점하고 있었고, 고농도 조건의 탈질세균 군집의 풍부도가 저농도 조건에 비해 더 높고, phylotype의 종류가 현저하게 변화되는 경향을 확인하였다. 본 연구결과는 습지토양의 탈질세균 군집이 매우 다양한 종류로 이루어져 있고, 이산화탄소의 증가에도 큰 영향을 받지 않는 상당히 안정적인 우점 개체군이 존재하고 있는 반면, 전체 phylotype의 약 60％는 이산화탄소 증가에 따라 민감하게 변화함을 보여주었다.

• 한국토양비료학회지
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• 제44권6호
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• pp.1089-1094
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• 2011

주암호 상수원 상류지역인 송광천에 위치한 봉산 인공습지의 수생태학적 효율 향상을 위한 관리 방안을 제시하기 위하여 시기별, 처리단계별 및 오염물질 부하량별 수처리 효율을 평가하였다. 유입원수의 BOD, SS, T-N 및 T-P의 평균 함량은 $1.87mg\;L^{-1}$, $1.62mg\;L^{-1}$, $11.47mg\;L^{-1}$ 및 $4.40mg\;L^{-1}$이었으며, 연평균 처리효율은 BOD, SS, T-N 및 T-P가 각각 26%, 18%, 16% 및 9%로서 전반적으로 처리효율이 낮았으나 유입수 농도가 높아서 오염물질의 제거량은 매우 높은 편이었다. 인공습지 처리단계별 BOD, SS, T-N 및 T-P 변화를 조사한 결과는 모든 항목에서 침강지의 처리효율이 가장 높았고 BOD와 T-P는 습지 II > 습지 I, SS와 T-N은습지 I > 습지 II 순으로 처리효율이 높았다. 인공습지 구성 시스템별 오염물질 부하량에 따른 오염물질 처리량은 BOD는 침강지 > 습지 I > 습지 II, SS는 침강지 > 습지 II > 습지 I, T-N은 습지 I > 침강지 > 습지 II, T-P는 습지 II > 침강지 > 습지 I 순으로 높았다.

• Journal of Ecology and Environment
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• 제42권3호
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• pp.90-102
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• 2018

Background: We sought to understand the relationship between the seed bank and vegetation in abandoned rice paddies in South Korea, in order to guide management of these sites. We investigated the floristic composition and species richness of the soil seed bank and ground vegetation in former paddies along three seral gradients (wet meadow, young forest, and mature forest) in Gwangneung Forest Biosphere Reserve. Results: Seed bank samples contained 59 species, of which the dominant families were Cyperaceae, Gramineae, and Polygonaceae. Species richness and seedling density (59 taxa and 19,121 germinants from all samples) were high. Carex spp. (11, 921 germinants) were the dominant taxa. The species composition in the seed bank changed gradually as the land transitioned from wet meadow to mature forest. Sørensen's index of similarity between above- and below-ground vegetation was 29.3% for wet meadow, 10.8% for young forest, and 2.1% for mature forest. Germinant density also declined, with 10, 256 germinants for wet meadow, 6445 germinants for young forest, and 2420 germinants for mature forest. Conclusions: Changes in aboveground environment and life history traits such as amphicarpic plants, likely affect the composition of soil seed bank species. Abandoned paddy fields may be good sites for restoration of wetland forest and conservation of wetland habitat. Some intervention may be required to promote the recovery of a natural species assemblage.

• 한국농공학회지
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• 제44권4호
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• pp.139-148
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• 2002

Pilot study was performed to examine the feasibility of the pond system for further polishing of treatment wetland effluent from December 2000 to June 2001. The wetland system used for the experiment was highly effective to treat the sewage during the growing season, but it was less effective and its effluent was still high to discharge to the receiving water body. Therefore, the wetland effluent may need further treatment to prevent water quality degradation. Pond system could be used to hold and further polish the wetland effluent during the winter season and ots feasibility was evaluated in this study. Additional water quality improvement was apparent in the pond system during winter season, and the pond effluent could be good enough to meet the effluent water quality standards if it is properly managed. Timing of the pond effluent discharge appears to be critical for pond system management because it is a closed system and whole water quality constituents are affected by physical, chemical, and biological pond environments. Once algae started to grow in mid-April, constituents in the pond water column interact each other actively and its control becomes more complicated. Therefore, upper layer of the pond water column which is clearer than the lower layer my need be discharged in March right after ice cover melted. In the experiment, water quality of the upper water column was markedly clear in March than ant other times probably because of freezing-thawing effect. The remaining lower water column could be further treated by natural purification as temperature goes up or diluted with better quality of wetland effluent for appropriate water uses. This study demonstrated the feasibility of pond system for subsequent management of wetland effluent during the winter season, however, more study is needed for field application.

• Journal of Ecology and Environment
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• 제34권3호
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• pp.323-331
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• 2011

Biodiversity and the community composition of micro-eukaryotic organisms were investigated in the Upo wetland in Korea using molecular analysis. Molecular identification was performed using cytochrome oxidase I (COI) and small subunit ribosomal DNA (SSU rDNA). The genomic DNA was isolated directly from soil samples. The COI and SSU rDNA regions were amplified using universal primers and then sequenced after cloning. In a similarity search of the obtained sequences with BLAST in the Genbank database, the closely related sequences from NCBI were used to identify the amplified sequences. A total of six eukaryotic groups (Annelida, Arthropoda, Rotifera, Chlorophyta, Bacillariophyta, and Stramenopiles) with COI and six groups (Annelida, Arthropoda, Rotifera, Alveolata, Fungi, and Apicomplexa) with SSU rDNA genes were determined in the Upo wetland. Among 38 taxa in 20 genera, which are closely related to the amplified sequences, 10 genera (50%) were newly reported in Korea and five genera (25%) were shown to be distributed in the Upo wetland. This approach is applicable to the development of an efficient method for monitoring biodiversity without traditional taxonomic processes and is expected to produce more accurate results in depositing molecular barcode data in the near future.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2005년도 학술발표논문집
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• pp.557-562
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• 2005

The field scale experiment was performed to examine the effect of plant coverage on the constructed wetland performance and recommend the optimum development and management of macrophyte communities. Four sets(each set of 0.88ha) of wetland (0.8ha) and pond(0.08ha) systems were used. Water flowing into the Seokmoon estuarine reservoir from the Dangjin stream was pumped into wetland system. Water depth was maintained at $0.3{\sim}0.5m$ and hydraulic retention time was managed to about $2{\sim}5$ days; emergent plants were allowed to grow in the wetlands. After three growing seasons of the construction of wetlands, plant coverage was about 95%, even with no plantation, from bare soil surfaces at the initial stage. Dead vegetation affected nitrogen removal during winter because it is a source of organic carbon which is an essential parameter in denitrification. Biomass harvesting is not a realistic management option for most constructed wetland systems because it could only slightly increase the removal rate and provide a minor nitrogen removal pathway due to lack of organic carbon.

• 한국토양비료학회지
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• 제45권1호
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• pp.20-24
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• 2012

Denitrification rate was determined for various freshwater wetland types in the Mississippi River Coastal delta plain. Site 1 and 4 were collected from forested-tupelo dominated wetland, and site 2 and 3 were from floating emergent marsh. The maximum $N_2O$ emission was $7.47mg\;N\;m^{-2}$ for site 1 at day 6 after the addition of nitrate, $6.96mg\;N\;m^{-2}$ for site 2 at day 4, $6.63mg\;N\;m^{-2}$ for site 3 at day 3, and $9.64mg\;N\;m^{-2}$ for site 4 at day 4. The denitrification rate was determined using the acetylene inhibition method $1.24mg\;N\;m^{-2}d^{-1}$ for site 1, $1.93mg\;N\;m^{-2}d^{-1}$ for site 2, $2.24mg\;N\;m^{-2}d^{-1}$ for site 3, and $2.78mg\;N\;m^{-2}d^{-1}$ for site 4. The maximum denitrification rate was in the order of site 4 > site 3 > site 2 > site 1.

• Journal of Biosystems Engineering
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• 제26권1호
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• pp.1-10
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• 2001

Interactions between cage wheel and soil under the wet paddy field condition were analyzed. The cage wheel as a traction aid to driving tires of tractor was attached to the outside of the tires. The driving torque transmitted only to the cage wheel was measured and its effect on the total driving torque by both the tires and cage wheel was analyzed. Mathematical models were developed to predict the soil thrusts y a single lug and by the cage wheel with many lugs, respectively. Experimental results showed that as the diameter of cage wheel increased, positive effects of the cage wheel on the traction also increased. About 33-40% of the total traction force was obtained by the cage wheel with a diameter 1,182mm and 49-55% with a diameter 1,222mm. The peak thrust of the single lug of cage wheel increased by 31% and 59%, respectively when the diameter of the cage wheel increased from 1,182mm to 1,222mm and 1,262mm. The thrust by the cage wheel was estimated by using the developed mathematical models and the results were proved that the models are reliable for the estimation of the traction by the cage wheels.

• 한국농공학회지
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• 제42권3호
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• pp.66-75
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• 2000

Effect of reclaimed sewage on the paddy rice culture was examined by field experiment for two consecutive years. The domestic sewage was treated by the constructed wetland and the effluent of the treatment wetland was used for irrigation water. The reclaimed sewage was diluted before irrigation in the first year and it was used without dilution in the second year experiment. Growth components and yields were compared against the control plot where conventional method was applied. And also soil characteristics of the plots before and after reclaimed sewage irrigation were analyzed Generally addition of the reclaimed sewage irrigation didn't affect paddy rice culture adversely and even enhancement was observed. Fertilization was thought to be important factor for rice culture rather than irrigation water quality. Conventional fertilization and reclaimed sewage irrigation which contained high nutrient concentration resulted in better growth and more yield. Unlike widespread concern lodging did not happen even in the case of irrigation with average 90mg/L of T-N and conventional fertilization. Soil characteristics changed after irrigation and significant EC increasing was observed for the reclaimed sewage irrigation plots. From soil analyses salt accumulation could be a more potential problem than nutrients like nitrogen and phosphorus in the use of reclaimed sewage irrigation. Overall reclaimed sewage irrigation was thought to be one of practical alternatives for the ultimate disposal of sewage in rural area.

• 한국환경복원기술학회지
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• 제5권6호
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• pp.24-29
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• 2002

Nitrate removal rate in three cattail wetland cells was investigated. They were a part of a pond-wetland system for stream water treatment demonstration. The system was composed of two ponds and six wetland cells. The acreage of each cell was approximately $150m^2$. The earth works for the system were finished from April 2000 to May 2000 and cattails were planted in the three cells in June 2000. Waters of Sinyang Stream flowing into Kohung Estuarine Lake were pumped into a primary pond, whose effluent was discharged into a secondary pond. The reservoir was formed by a tidal marsh reclamation project and located in southern coastal area of Korean Peninsula. Effluents from the secondary pond were funneled into the three cells. Volumes and water quality of inflow and outflow were analyzed from July 2000 through January 2001. Inflow and outflow averaged $20.2m^3/day$ and $19.8m^3/day$, respectively. Hydraulic retention time was about 1.6 days. Average influent and effluent nitrate concentration was $1.98mg/{\ell}$, $1.38mg/{\ell}$, respectively. Nitrate removal rate averaged $82.6mg\;m^{-2}\;day^{-1}$. Seasonal changes of nitrate retention rates were closely related to those of wetland cell temperatures. The average nitrate removal rate in the cells was a little lower, compared with that of $125.0mg\;m^{-2}\;day^{-1}$ for the wetlands operating in North America. This could be attributed to the initial stage of the cells and inclusion of three cold months into the seven-month study period. Root rhizosphere in wetland soils and litter-soil layers on cell bottoms could not developed. Increase of standing density of cattails within a few years will establish both root zones suitable for the nitrification of ammonia to nitrates and substrates beneficial to the denitrification of nitrates into nitrogen gases, which may lead to increase of the nitrate retention rate.