• Animal cells and systems
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• 제6권1호
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• pp.59-64
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• 2002

To restore the forest ecosystem severely damaged by air pollution around industrial complexes, plants tolerant to the polluted environment were selected by transplant and pot culture experiments. A restoration plan by arranging those tolerant species was prepared based on the ecological diagnostic results on an area that requires restoration. Transplant experiment in Ulsan and Yeocheon areas, the representative industrial complexes in Korea, selected eight tolerant species of Quercus aliena, Q. acutissima, Q. dentata, Q. mongolica, Q. serrata, Ligustrum japonicum, Styrax japonica, and Poncirus trifoliata. Cultivation in the polluted soil transported from the Ulsan and Yeocheon industrial complexes chose five tolerant plants of Q. aliena, Q. acutissima, Q. serrata, Styrax japonica, and Alnus firma. A plan to restore the forest ecosystem of Mt. Dotjil, which experienced the severest ecosystem degradation in the Ulsan industrial complex, was prepared by applying those tolerant species along with treatment for soil amelioration. Arrangement of the tolerant species was designed by considering their ecological characteristics including distribution range on topography and shade tolerance. Soil amelioration was focused on the improvement of fertility and moisture conditions.

• Journal of Ecology and Environment
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• 제43권1호
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• pp.61-72
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• 2019

Background: Organic carbon stored in coastal wetlands, which comprises the major part of oceanic "blue carbon," is a subject of growing interest and concern. In this study, organic carbon storage in coastal wetlands and its economic value were estimated using the raw data of 25 studies related to soil carbon storage. Data were collected from three tidal flats (one protected and two developed areas) and two estuarine salt marshes (one protected and one restored area). Bulk density, soil organic matter content, and standing biomass of vegetation were all considered, with Monte Carlo simulation applied to estimate the uncertainty. Results: Mean carbon storage in two salt marshes ranged between 14.6 and $25.5kg\;C\;m^{-2}$. Mean carbon storage in tidal flats ranged from 18.2 to $28.6kg\;C\;m^{-2}$, with variability possibly related to soil texture. The economic value of stored carbon was estimated by comparison with the price of carbon in the emission trading market. The value of US $ $6600\;ha^{-1}$ is ~ 45% of previously estimated ecosystem services from fishery production and water purification functions in coastal areas. Conclusions: Although our study sites do not cover all types of large marine ecosystem, this study highlights the substantial contribution of coastal wetlands as carbon sinks and the importance of conserving these habitats to maximize their ecosystem services.

• Journal of Ecology and Environment
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• 제42권4호
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• pp.155-162
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• 2018

Background: In ecosystem carbon cycle studies, distinguishing between $CO_2$ emitted by roots and by microbes remains very difficult because it is mixed before being released into the atmosphere. Currently, no method for quantifying root and microbial respiration is effective. Therefore, this study investigated the relationship between soil respiration and underground root biomass at varying distances from the tree and tested possibilities for measuring root and microbial respiration. Methods: Soil respiration was measured by the closed chamber method, in which acrylic collars were placed at regular intervals from the tree base. Measurements were made irregularly during one season, including high temperatures in summer and low temperatures in autumn; the soil's temperature and moisture content were also collected. After measurements, roots of each plot were collected, and their dry matter biomass measured to analyze relationships between root biomass and soil respiration. Results: Apart from root biomass, which affects soil's temperature and moisture, no other factors affecting soil respiration showed significant differences between measuring points. At each point, soil respiration showed clear seasonal variations and high exponential correlation with increasing soil temperatures. The root biomass decreased exponentially with increasing distance from the tree. The rate of soil respiration was also highly correlated exponentially with root biomass. Based on these results, the average rate of root respiration in the soil was estimated to be 34.4% (26.6~43.1%). Conclusions: In this study, attempts were made to differentiate the root respiration rate by analyzing the distribution of root biomass and resulting changes in soil respiration. As distance from the tree increased, root biomass and soil respiration values were shown to strongly decrease exponentially. Root biomass increased logarithmically with increases in soil respiration. In addition, soil respiration and underground root biomass were logarithmically related; the calculated root-breathing rate was around 44%. This study method is applicable for determining root and microbial respiration in forest ecosystem carbon cycle research. However, more data should be collected on the distribution of root biomass and the correlated soil respiration.

• 한국환경복원기술학회지
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• 제3권1호
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• pp.70-79
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• 2000

Arbuscular mycorrhizal(AM) fungi have significant role for ecosystem structure and function. They are the major component of forest soil ecosystems and critically important for water and nutrient cycling in the system. To understand the ecology of AM fungi the fungal spores were collected, identified and counted in forest soils under various climatic and edaphic conditions. In relation to soil depth 90% of AM fungi spores and mycorrhizas distributed within 15cm soil depth. Number of spores per $100m{\ell}$ forest soil volume was 5 to 36 spores from 1 to 3 fungal species. AM fungal species diversity was higher in warmer climates, and more moist and fertile soils. The most frequently found species were Gigaspora decipiens irrespective of soil moisture and Gi. gigantea irrespective of soil fertility. In the Jeju island the soils of Cryptomeria japonica plantations and Miscanthus sinensis var. purpurascens meadow had more AM spores than the other soils. We suggest AM fungi be considered as keystones species when restoring a disturbed forest ecosystem.

• 농약과학회지
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• 제2권3호
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• pp.96-106
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• 1998

Micro-ecosystem (pot)중 quinclorac 토양잔류물의 행적을 구명하기 위하여 이화학적 특성이 상이하고 quinclorac의 신생 및 숙성 잔류물을 함유한 2종의 논토양에 42일간 벼를 재배하였다. 벼의 재배 유무와 무관하게 quinclorac 신생잔류물과 숙성 잔류물을 함유한 토양으로부터 방출된 $^{14}CO_{2}$의 양은 두 토양 모두에서 총처리 방사능의 2.2% 미만으로서 토앙 미생물에 의한 분해가 용이하지 않았음을 시사하였다. 서로 다른 quinclorac 토양잔류물을 함유한 두 토양에서 벼에 흡수 이행된 $^{14}C$의 양은 토양 A보다 유기물 함량과 점토의 함량이 적은 토양 B에서 더 많았고, quinclorac 잔류물의 흡수이행은 신생잔류물을 처리한 토양에서 보다 숙성 잔류물을 함유한 토양에서 적었다. 벼 수확 후 신생잔류물과 숙성잔류물을 함유한 토양 A에 잔류하는 $^{14}C$는 각각 총처리 방사능의 84.5와 86.3%로 비슷하였으며, 토양 B에서는 각각 61.8과 67.7%였다. 반면 벼를 재배하지 않은 토양중에서는 98.3%이상이 잔류하여 quinclorac이 화학적으로나 미생물적으로 비교적 안정한 화합물임을 입증하였다. Quinclorac의 추출불가 토양속박 잔류물은 토양 유기물에 강력하게 흡착 또는 결합되어 있고 대부분이 fulvic acid에 혼입되어 있었다.

• Journal of Ginseng Research
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• 제40권1호
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• pp.28-37
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• 2016

Background: Panax ginseng cannot be cultivated on the same land consecutively for an extended period, and the underlying mechanism regarding microorganisms is still being explored. Methods: Polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) and BIO-LOG methods were used to evaluate the microbial genetic and functional diversity associated with the P. ginseng rhizosphere soil in various cultivation ages and modes. Results: The analysis of microbial diversity using PCR-DGGE showed that microbial communities were significantly variable in composition, of which six bacterial phyla and seven fungal classes were detected in P. ginseng soil. Among them, Proteobacteria and Hypocreales dominated. Fusarium oxysporum, a soilborne pathogen, was found in all P. ginseng soil samples except R0. The results from functional diversity suggested that the microbial metabolic diversity of fallow soil abandoned in 2003was the maximum and transplanted soil was higher than direct-seeding soil and the forest soil uncultivated P. ginseng, whereas the increase in cultivation ages in the same mode led to decreases in microbial diversity in P. ginseng soil. Carbohydrates, amino acids, and polymers were the main carbon sources utilized. Furthermore, the microbial diversity index and multivariate comparisons indicated that the augmentation of P. ginseng cultivation ages resulted in decreased bacterial diversity and increased fungal diversity, whereas microbial diversity was improved strikingly in transplanted soil and fallow soil abandoned for at least one decade. Conclusion: The key factors for discontinuous P. ginseng cultivation were the lack of balance in rhizosphere microbial communities and the outbreak of soilborne diseases caused by the accumulation of its root exudates.

• Genomics & Informatics
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• 제11권3호
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• pp.114-120
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• 2013

The microbial diversity in soil ecosystems is higher than in any other microbial ecosystem. The majority of soil microorganisms has not been characterized, because the dominant members have not been readily culturable on standard cultivation media; therefore, the soil ecosystem is a great reservoir for the discovery of novel microbial enzymes and bioactivities. The soil metagenome, the collective microbial genome, could be cloned and sequenced directly from soils to search for novel microbial resources. This review summarizes the microbial diversity in soils and the efforts to search for microbial resources from the soil metagenome, with more emphasis on the potential of bioprospecting metagenomics and recent discoveries.

• 농업과학연구
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• 제33권1호
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• pp.85-95
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• 2006

A model experiment has been performed to get the heat transfer coefficient on the soil surface in the closed ecosystem. The heat flux on the soil surface was measured and the heat transfer coefficient was derived in the following two cases with 5-stepped control of inside air current speed. One case was that heat flowed from air to soil and the other case was that heat flowed from soil to air. Three dimensional CFD model has been set to simulate thermal environment in the closed ecosystem including soil layers. The standard $k-{\varepsilon}$ model of the CFD program was chosen for turbulence model and heating wire buried in the soil layers was set as heat source option to simulate the case when the temperature of soil surface was higher than that of inside air in the closed ecosystem. Between one case that heat flowed from air to soil and the other case that heat flowed from soil to air, there were big differences in the temperature distribution of soil layers and the heat transfer coefficient of the soil surface. The increasing rate of heat transfer coefficient on each case according to the increase of inside air current speed was similar to each other and it respectively increased linearly. But the heat transfer coefficient on the case that heat flowed from soil to air was much bigger than that of the other case. The model was validated by comparing simulated values of CFD model with measured values of the model experiment. Simulated and measured temperature of inside air and soil layers, and heat transfer coefficient of the soil surface were well accorded and the range of corrected $R^2$ was 0.664 to 0.875. The developed CFD model was well simulated in parts of the temperature of inside air and soil layers, the distribution of the inside air current speed, and heat transfer coefficient of the soil surface were able to be quantitatively analyzed by using this model. Therefore, the model would be applied and used for analysis of heat transfer coefficient between air and surface in various agricultural facilities.

• 한국산림과학회지
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• 제86권1호
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• pp.98-104
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• 1997

대기오염의 장기화에 따라 토양오염이 심화된 것으로 추측되는 서울 남산의 토양을 대기오염이 심하지 않은 것으로 판단되는 계방산 토양의 화학적 특성과 비교하여 남산토양의 오염도를 평가하며, 질소 및 황의 무기화에 관여하는 미생물을 동시에 정량하여 질소 및 황의 무기화에 관여하는 미생물군을 토양오염도 평가기준으로 활용할 수 있는지 알아보았다. 남산의 토양은 계방산에 비하여 10배 이상 수소이온의 농도가 높아 토양 산성화가 상대적으로 심하였다. 특히, 남산토양은 양이온의 용탈이 심하고 치환성 알루미늄은 많아져 남산지역 토양 생태계에 큰 문제가 발생하였음을 나타냈다. 토양 산성화의 주요인은 황산화물의 집적으로 추정되지만 황산환원균의 활성은 지역간에 유의차를 발견할 수 없어서 미생물 동태가 단순한 인자만이 아닌 복합적인 요인에 의하여 조절됨을 짐작할 수 있었다. 반면, 탈질기작에 관여하는 세균의 동태는 남산의 소나무림에 비하여 계방산의 소나무림에서 활발한 것으로 평가되어 토양생태계의 전반적인 미생물 활성도나 건전도의 지표로 질소의 무기화에 관여하는 미생물의 정량기법을 검토해 볼만하다.

• 대한원격탐사학회지
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• 제34권2_1호
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• pp.179-190
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• 2018

본 연구는 하천 유역의 정비사업 전 후의 토양유실위험도를 비교하기 위하여 GIS 및 디지타이징 자료를 토대로 수정범용토양유실공식(RUSLE)을 활용하여 분석하였다. 토양유실량을 파악하기 위하여 토지피복지도, 지형도, 토양도, 강수량 등의 자료들을 이용하였으며, 금호강 유역의 수변지역을 범위로 디지타이징한 후, 유역을 행정구역 단위로 분할하여 분석하였다. 하천 정비 전('8)과 후('16)로 토양유실이 전혀 일어나지 않는 지역(클래스 1)에서 심하게 일어나는 지역(클래스 5) 등 총 5단계로 구분하여 분석한 결과, 사업('16) 후 전체지역에 대하여 1, 5 클래스는 감소, 2~4 클래스는 증가한 것으로 나타났다. 대구와 영천은 5 클래스의 면적이 감소하였고, 경산은 5 클래스의 지역이 존재하지 않았다. 이러한 원인은 공원조성과 인공시설물 확대, 농경지 감소 등으로 인하여 5 클래스의 지역이 감소한 것으로 판단되며, 수변지역의 준설 및 공원조성을 위한 하안선 단순화는 하천 유량 및 유속에 의한 토양유실량 증가가 일어난 것으로 추정된다.