• 한국환경과학회지
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• 제4권5호
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• pp.83-83
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• 1995

The increase of population and industrial activities had brought into eutrophication in the Nakdong river. A remarkable acceleration of eutrophication brought about serious problems for water supply. Therefore, for the purpose of conservation of water quality in the Nakdong river it is necessary to control nutrients. MBOD method was use to evaluate algal growth limiting factor and algal growth potential in the Nakdong river from June to August 1994. The modified biochemical oxygen demand(MBOD) depends on the amount of available inorganic nutrient and organic substrate during 5 day incubation in the dark at 20$^{circ}C$. The MBOD assay depends on inorganic nutrients such as P and N as well as reduced carbon and called the MBOD, the MBOD-P, and the MBOD-N, respectively. The results of bioassay by MBOD(Modified BOD) method showed that the MBOD, MBOD-P and MBOD-N value were found to be in the ranges of 3.8∼96.0 mg$O_2$/l, 5.6∼94.0 mg$O_2$/l and 42.0∼220 mg$O_2$/l, respectively. And the the bioassay value was found to be the highest in Koryong area and the lowest in Waekwan area throughout the Nakdong river. The variations of MBOD-P and MBOD-N value showed similar tendencies to the variations of phosphorus and nitrogen value, respectively. By MBOD method, the relationships of MBOD, MBOD-P and MBOD-N value were MBOD ≒ MBOD-P 《 MBOD-N. The MBOD value was nearly equal to the MBOD-P value, and the MBOD-N value was 3 to 20 times more than the MBOD-P value, approximately. Therefore, in the Nakdong river, phosphorus was the limiting factor for algal growth during summer season. The algal growth potential as the concentration of chlorophyll-a in the summer was maximum 5 times more than standing crop as it.

• 한국수자원학회논문집
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• 제46권7호
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• pp.697-706
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• 2013

최근 한국은 기후변화로 인한 기온 및 수온 상승, 빈번한 집중호우와 친수공간 조성에 따른 적극적인 하천의 활용 등으로 인하여 하천 및 저수지 내 수질관리에 있어 해결해야 하는 많은 문제점을 가지고 있다. 본 연구는 효율적인 수질관리를 위하여 인공신경망을 이용한 단기조류예측모형 구축에 관한 연구이다. 대상지역으로 조류가 번식하기 좋은 조건을 지니고 있는 금강유역 내 대청호를 선정하였고 설치되어 있는 수질 자동측정망의 일 단위자료를 이용하였다. 다층전방향신경망의 역전파 알고리즘을 이용하여 단기(1일, 3일, 7일) 조류를 예측할 수 있는 모형을 구축하였다. 본 모형에서는 대청호 내 수문 및 수질성분을 교차상관분석을 기초하여 단기조류예측모형의 입력 성분을 선정한 후 다양한 조류예측 신경망 모형을 구축하여 결과에 대한 검증을 실시하였다. 구축된 단기조류예측모형은 자연발생적인 기작과 유사한 현상을 재현할 수 있는 다양한 수질인자를 고려하여 단기조류예측모형을 구축한 경우 예측의 정확도가 높게 도출되었다. 본 연구는 신경망모형의 최대 장점인 비선형성 및 간편성 등을 고려하였을 때 우리나라의 수질예측에 적합한 신경망 모형을 구축할 수 있으며 이를 통한 하천 및 호수 내 효율적인 수질관리 방안을 제시할 수 있을 것이다.

• 생태와환경
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• 제43권2호
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• pp.221-231
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• 2010

국내에서 널리 분포하여 쉽게 구할 수 있는 천연재료인 상수리나무, 밤나무, 녹차, 황토, 맥반석, 제올라이트와 혼합물 등 7가지 물질의 남조와 녹조류 성장 억제능을 파악하기 위하여, 단순 추출법을 이용하여 얻은 각 물질을 농도별(1, 5, 10 mg $L^{-1}$)로 배양조류에 처리하고 각 조류의 성장 특성을 조사하였다. 분리형 남조 Microcystis aeruginosa, 군체형 M. aeruginosa 등은 저농도의 상수리나무, 밤나무, 제오라이트에 의해서 60% 이상의 높은 조류억제능을 보였으며, 녹조 Scenedesmus quadricauda는 녹차, 상수리나무에서 50% 이하의 억제능을 보였으며, 제오라이트에서는 65% 이상 성장이 억제되었다. 녹차를 포함한 대부분의 물질에서 낮은 농도인 1 mg $L^{-1}$에서 녹조 Chlorella vulgaris의 성장을 촉진하였으며, 황토는 S. quadricauda 성장을 촉진하였다. 따라서 부영양호수에서 흔히 발생되는 남조발생 억제에는 상수리나무, 밤나무, 제올라이트가 적합할 것으로 판단되었으며, 녹차, 황토나 맥반석 등은 녹조류 대량배양이나 배지로서 이용 가능성이 높다고 사료되었다.

• 환경영향평가
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• 제25권4호
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• pp.248-260
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• 2016

본 연구의 목적은 대청호의 녹조발생 저감을 위해 우심지역인 추소수역과 그 상류 소옥천 유역에서의 다양한 수질개선 대책들을 제시하고, 대책 시행 시 저수지 수질개선 효과를 평가하는데 있다. 대책별 모의 시나리오는 유역대책과 저수지 내 대책으로 분류하였으며, 시나리오별 녹조저감 효과는 2차원 수리 수질모델을 적용하여 모의하였다. 유역 대책은 점오염원, 비점오염원, 복합 대책으로 시나리오를 구성하였으며, 호내 대책은 추소수역의 퇴적물 처리 및 소옥천 유입수의 인 처리시설 설치를 고려하였다. 연구결과, 개별 대책의 녹조저감 효과는 수문상황에 따라 다르게 나타났으며, 강우가 많은 해에는 비점오염 부하량이 증가하여 비점오염원 저감대책(NPS1~NPS4)이 효과적인 것으로 평가되었으며, 강우가 적은 해에는 평상시 호 내로 유입하는 인의 유입부하를 저감하는 화학적 인처리시설 설치(LS2)가 효과적인 것으로 평가되었다. 특히, 유역에서 발생되는 축산 분뇨를 전량 수거 처리하고 농경지에는 표준시비량만을 적용한 방안(NPS1)이 수질개선에 가장 효과적인 것으로 나타났다.

• 생태와환경
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• 제33권2호통권90호
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• pp.136-144
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• 2000

팔당호 주변에서 자생하는 식물체를 이용하여 실험실 내에서 배양된 남조류에 투여하여 조류증식 억제 효율을 조사하였다. 조류 성장 억제 효과에 있어 육상식물을 이용하는 경우 조류 밀도가 10$^{4}$ cells/ml 범위에서의 0.5g/l 투여량은 전혀 효과를 나타내지 못했던 반면, 2.5 g/l 투여량에서는 95% 이상의 효과를 보였다. 조류 밀도가 10$^{6}$ cells/ml 범위에서의 육상식물 투여량은 2.5 g/l 이상이 필요했다. 조류성장 억제에 육상식물은 잣잎, 수생식물은 애기마름이 큰 효과를 보였다. 애기마름 투여조는 조류 밀도가 10$^{6}$ cells/ml 범위에서도 2.5 g/l 투여량으로 50%의 억제 효율이 나타났다. 식물을 이용한 조류 증식 억제 효과는 식물 투여 후 7일째 후 가장 효과가 좋은 것으로 나타났다. 습체, 건체, 추출물 비교시 추출물이 가장 효과가 좋은 것으로 육상식물 투여조의 경우 1.25 g/l 투여량에 비해 2.5 g/l 투여량에서 현저한 효과를 보였고, 애기마름은 1.25 g/l 투여량에서도 99%의 효과를 보였다. 건체식물은 습체식물에 비해 초기에도 높은 효과를 보였다. 조류의 비증식속도로 보았을 때도 식물체 추출물을 투여했을 때 가장 효과가 좋았고 다음으로 건체, 습체식물 투여순으로 조류 증식억제 효과를 나타내었다.

• 한국환경과학회지
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• 제25권7호
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• pp.937-950
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• 2016

Algal blooming in 4 major rivers introduces substantial impacts to water front activity. Concentrations of algae are increasing at major points along the Geum River. Ecosystem food webs can be affected by algal blooming because blue-green algae release toxic materials. Even though there have been many studies on blue-green algae, its causality to environmental factors has not been completely determined yet. This study analyzed the exclusive correlation between various hydrometeorological, water quality, and hydrologic variables and the cell number of cyanobacteria to understand causality of blue-green algae in the Geum River. A prewhitening process was introduced to remove the autocorrelation structure and periodicity, which is useful to evaluate the effective relationship between two time series.

• ALGAE
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• 제38권4호
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• pp.203-215
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• 2023

Oomycete pathogens are one of the most serious threats to the rapidly growing global algae aquaculture industry but research into how they spread and how algae respond to infection is unresolved, let alone a proper classification of the pathogens. Even the taxonomy of the genera Pythium and Olpidiopsis, which contain the most economically damaging pathogens in red algal aquaculture, and are among the best studied, needs urgent clarification, as existing morphological classifications and molecular evidence are often inconsistent. Recent studies have reported a number of genes involved in defense responses against oomycete pathogens in red algae, including pattern-triggered immunity and effector-triggered immunity. Accumulating evidence also suggests that calcium-mediated reactive oxygen species signaling plays an important role in the response of red algae to oomycete pathogens. Current management strategies to control oomycete pathogens in aquaculture are based on the high resistance of red algae to abiotic stress, these have environmental consequences and are not fully effective. Here, we compile a revised list of oomycete pathogens known to infect marine red algae and outline the current taxonomic situation. We also review recent research on the molecular and cellular responses of red algae to oomycete infection that has only recently begun, and outline the methods currently used to control disease in the field.

• ALGAE
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• 제30권3호
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• pp.217-222
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• 2015

Pythium species (Pythiales, Oomycetes) are well known as the algal pathogen that causes red rot disease in Pyropia / Porphyra species (Bangiales, Rhodophyta). Accurate species identification of the pathogen is important to finding a scientific solution for the disease and to clarify the host-parasite relationship. In Korea, only Pythium porphyrae has been reported from Pyropia species, with identifications based on culture and genetic analysis of the nuclear internal transcribed spacer (ITS) region. Recent fungal DNA barcoding studies have shown the low taxonomic resolution of the ITS region and suggested the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene as an alternative molecular marker to identify Pythium species. In this study, we applied an analysis of both the ITS and cox1 regions to clarify the taxonomic relationships of Korean Pythium species. From the results, the two closely related Pythium species (P. chondricola and P. porphyrae) showed the same ITS sequence, while the cox1 marker successfully discriminated P. chondricola from P. porphyrae. This is the first report of the presence of P. chondricola from the infected blade of Pyropia yezoensis in Asia. This finding of the algal pathogen provides important information for identifying and determining the distribution of Pythium species. Further studies are also needed to confirm whether P. chondricola and P. porphyrae are coexisting as algal pathogens of Pyropia species in Korea.

• Journal of Microbiology and Biotechnology
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• 제23권9호
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• pp.1260-1268
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• 2013

A series of experiments were carried out with three native strains of microalgae to measure growth rates, biomass, and lipid productivities. Scenedesmus sp. IMMTCC-6 had better biomass growth rate and higher lipid production. The growth, lipid accumulation, and carbon dioxide ($CO_2$) consumption rate of Scenedesmus sp. IMMTCC-6 were tested under different NaOH concentrations in modified BBM. The algal strain showed the maximum specific growth rate (0.474/day), biomass productivity (110.9 mg $l^{-1}d^{-1}$), and $CO_2$ consumption rate (208.4 mg $l^{-1}d^{-1}$) with an NaOH concentration of 0.005 M on the $8^{th}$ day of cultivation. These values were 2.03-, 6.89-, and 6.88-fold more than the algal cultures grown in control conditions (having no NaOH and $CO_2$). The $CO_2$ fixing efficiency of the microalga with other alternative carbon sources like $Na_2CO_3$ and $NaHCO_3$ was also investigated and compared. The optimized experimental parameters at shake-flask scale were implemented for scaling up the process in a self-engineered photobioreactor. A significant increase in lipid accumulation (14.23% to 31.74%) by the algal strain from the logarithmic to stationary phases was obtained. The algal lipids were mainly composed of $C_{16}/C_{18}$ fatty acids, and are desirable for biodiesel production. The study suggests that microalga Scenedesmus sp. IMMTCC-6 is an efficient strain for biodiesel production and $CO_2$ biofixation using stripping solution of NaOH in a cyclic process.

• Journal of Microbiology and Biotechnology
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• 제30권7호
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• pp.1072-1081
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• 2020

Screening suitable strains with high temperature adaptability is of great importance for reducing the cost of temperature control in microalgae cultivation, especially in summer. To obtain high temperature-tolerant diatoms, water samples were collected in summer from 7 different regions of China across the Northeast, North and East. A total of 731 water samples was collected and from them 131 diatom strains were isolated and identified based on the 18S rRNA sequences. Forty-nine strains out of the 131 diatoms could survive at 30℃, and 6 strains with relatively high biomass and lipid content at high temperature were selected and were found to be able to grow at 35℃. Cyclotella sp. HB162 had the highest dry biomass of 0.46 g/l and relatively high triacylglycerol (TAG) content of 237.4 mg/g dry biomass. The highest TAG content of 246.4 mg/g dry biomass was obtained in Fistulifera sp. HB236, while Nitzschia palea HB170 had high dry biomass (0.33 g/l) but relatively low TAG content (105.9 mg/g dry biomass). N. palea HB170 and Fistulifera sp. HB236 presented relatively stable growth rates and lipid yields under fluctuating temperatures ranging from 28 to 35℃, while Cyclotella HB162 maintained high lipid yield at temperatures below 25℃. The percentage of saturated fatty acids and monounsaturated fatty acids in all the 6 strains was 84-91% in total lipids and 90-94% in TAGs, which makes them the ideal feedstock for biodiesel.